IXTA96P085T TRL - IXYS - Datasheet.Live

PIC18F87J50 Family

Data Sheet

64/80-Pin High-Performance,

1-Mbit Flash USB Microcontrollers

with nanoWatt Technology

Information contained in this publication regarding device

applications and the like is provided only for your convenience

and may be superseded by updates. It is your responsibility to

ensure that your application meets with your specifications.

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suits, or expenses resulting from such use. No licenses are

conveyed, implicitly or otherwise, under any Microchip

intellectual property rights.

Trademarks

The Microchip name and logo, the Microchip logo, dsPIC,

KEELOQ, KEELOQ logo, MPLAB, PIC, PICmicro, PICSTART,

rfPIC and UNI/O are registered trademarks of Microchip

Technology Incorporated in the U.S.A. and other countries.

FilterLab, Hampshire, HI-TECH C, Linear Active Thermistor,

MXDEV, MXLAB, SEEVAL and The Embedded Control

Solutions Company are registered trademarks of Microchip

Technology Incorporated in the U.S.A.

Analog-for-the-Digital Age, Application Maestro, CodeGuard,

dsPICDEM, dsPICDEM.net, dsPICworks, dsSPEAK, ECAN,

ECONOMONITOR, FanSense, HI-TIDE, In-Circuit Serial

Programming, ICSP, Mindi, MiWi, MPASM, MPLAB Certified

logo, MPLIB, MPLINK, mTouch, Octopus, Omniscient Code

Generation, PICC, PICC-18, PICDEM, PICDEM.net, PICkit,

PICtail, PIC32 logo, REAL ICE, rfLAB, Select Mode, Total

Endurance, TSHARC, UniWinDriver, WiperLock and ZENA

are trademarks of Microchip Technology Incorporated in the

U.S.A. and other countries.

SQTP is a service mark of Microchip Technology Incorporated

in the U.S.A.

All other trademarks mentioned herein are property of their

respective companies.

Printed on recycled paper.

Note the following details of the code protection feature on Microchip devices:

• Microchip products meet the specification contained in their particular Microchip Data Sheet.

• Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the

intended manner and under normal conditions.

• There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our

knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip’s Data

Sheets. Most likely, the person doing so is engaged in theft of intellectual property.

• Microchip is willing to work with the customer who is concerned about the integrity of their code.

• Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not

mean that we are guaranteeing the product as “unbreakable.”

Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our

products. Attempts to break Microchip’s code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts

allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act.

Microchip received ISO/TS-16949:2002 certification for its worldwide

headquarters, design and wafer fabrication facilities in Chandler and

Tempe, Arizona; Gresham, Oregon and design centers in California

and India. The Company’s quality system processes and procedures

are for its PIC® MCUs and dsPIC® DSCs, KEELOQ® code hopping

devices, Serial EEPROMs, microperipherals, nonvolatile memory and

analog products. In addition, Microchip’s quality system for the design

and manufacture of development systems is ISO 9001:2000 certified.

PIC18F87J50 FAMILY

Universal Serial Bus Features:

• USB V2.0 Compliant SIE

• Low Speed (1.5 Mb/s) and Full Speed (12 Mb/s)

• Supports Control, Interrupt, Isochronous and

Bulk Transfers

• Supports up to 32 Endpoints (16 bidirectional)

• 3.9-Kbyte Dual Access RAM for USB

• On-Chip USB Transceiver

Flexible Oscillator Structure:

• High-Precision PLL for USB

• Two External Clock modes, up to 48 MHz

• Internal 31 kHz Oscillator, Tunable Internal

Oscillator, 31 kHz to 8 MHz

• Secondary Oscillator using Timer1 @ 32 kHz

• Fail-Safe Clock Monitor:

- Allows for safe shutdown if any clock stops

Peripheral Highlights:

• High-Current Sink/Source 25 mA/25mA

(PORTB and PORTC)

• Four Programmable External Interrupts

• Four Input Change Interrupts

• Two Capture/Compare/PWM (CCP) modules

• Three Enhanced Capture/Compare/PWM (ECCP)

modules:

- One, two or four PWM outputs

- Selectable polarity

- Programmable dead time

- Auto-shutdown and auto-restart

• Two Master Synchronous Serial Port (MSSP)

modules supporting 3-Wire SPI (all 4 modes) and

I2C™ Master and Slave modes

• 8-Bit Parallel Master Port/Enhanced Parallel

Slave Port with 16 Address Lines

• Dual Analog Comparators with Input Multiplexing

Peripheral Highlights (continued):

• 10-Bit, up to 12-Channel Analog-to-Digital (A/D)

Converter module:

- Auto-acquisition capability

- Conversion available during Sleep

• Two Enhanced USART modules:

- Supports RS-485, RS-232 and LIN 1.2

- Auto-wake-up on Start bit

- Auto-Baud Detect

External Memory Bus

(80-pin devices only):

• Address Capability of up to 2 Mbytes

• 8-Bit or 16-Bit Interface

• 12-Bit, 16-Bit and 20-Bit Addressing modes

Special Microcontroller Features:

• 5.5V Tolerant Inputs (digital-only pins)

• Low-Power, High-Speed CMOS Flash Technology

• C Compiler Optimized Architecture for

Re-Entrant Code

• Power Management Features:

- Run: CPU on, peripherals on

- Idle: CPU off, peripherals on

- Sleep: CPU off, peripherals off

• Priority Levels for Interrupts

• Self-Programmable under Software Control

• 8 x 8 Single-Cycle Hardware Multiplier

• Extended Watchdog Timer (WDT):

- Programmable period from 4 ms to 131s

• Single-Supply In-Circuit Serial Programming™

(ICSP™) via Two Pins

• In-Circuit Debug (ICD) with 3 Breakpoints via

Two Pins

• Operating Voltage Range of 2.0V to 3.6V

• On-Chip 2.5V Regulator

• Flash Program Memory of 10000 Erase/Write

Cycles and 20-Year Data Retention

64/80-Pin High-Performance, 1-Mbit Flash USB

Microcontrollers with nanoWatt Technology

PIC18F87J50 FAMILY

Pin Diagrams

Device Flash Program

Memory (bytes)

SRAM Data

Memory

(bytes)

I/O 10-Bit

A/D (ch)

CCP/

ECCP

(PWM)

MSSP

EUSART

Comparators

Timers

8/16-Bit

External Bus

PMP/PSP

SPI Master

I2C™

PIC18F65J50 32K 3904* 49 8 2/3 2 Y Y 2 2 2/3 N Y

PIC18F66J50 64K 3904* 49 8 2/3 2 Y Y 2 2 2/3 N Y

PIC18F66J55 96K 3904* 49 8 2/3 2 Y Y 2 2 2/3 N Y

PIC18F67J50 128K 3904* 49 8 2/3 2 Y Y 2 2 2/3 N Y

PIC18F85J50 32K 3904* 65 12 2/3 2 Y Y 2 2 2/3 Y Y

PIC18F86J50 64K 3904* 65 12 2/3 2 Y Y 2 2 2/3 Y Y

PIC18F86J55 96K 3904* 65 12 2/3 2 Y Y 2 2 2/3 Y Y

PIC18F87J50 128K 3904* 65 12 2/3 2 Y Y 2 2 2/3 Y Y

* Includes the dual access RAM used by the USB module which is shared with data memory.

64-Pin TQFP

PIC18F6XJ5X

RE2/PMBE/P2B

RE3/PMA13/P3C/REFO

RE4/PMA12/P3B

RE5/PMA11/P1C

RE6/PMA10/P1B

RE7/PMA9/ECCP2(1)/P2A(1)

RD0/PMD0

VDD

VSS

RD1/PMD1

RD2/PMD2

RD3/PMD3

RD4/PMD4/SDO2

RD5/PMD5/SDI2/SDA2

RD6/PMD6/SCK2/SCL2

RD7/PMD7/SS2

RE1/PMWR/P2C

RE0/PMRD/P2D

RG0/PMA8/ECCP3/P3A

RG1/PMA7/TX2/CK2

RG2/PMA6/RX2/DT2

RG3/PMCS1/CCP4/P3D

MCLR

RG4/PMCS2/CCP5/P1D

VSS

VDDCORE/VCAP

RF7/SS1/C1OUT

RF6/AN11/C1INA

RF5/AN10/C1INB/CVREF

RF4/D+

RF3/D-

RF2/PMA5/AN7/C2INB

RB0/FLT0/INT0

RB1/INT1/PMA4

RB2/INT2/PMA3

RB3/INT3/PMA2

RB4/KBI0/PMA1

RB5/KBI1/PMA0

RB6/KBI2/PGC

VSS

OSC2/CLKO/RA6

OSC1/CLKI/RA7

VDD

RB7/KBI3/PGD

RC4/SDI1/SDA1

RC3/SCK1/SCL1

RC2/ECCP1/P1A

ENVREG

VUSB

AVDD

AVSS

RA3/AN3/VREF+

RA2/AN2/VREF-

RA1/AN1

RA0/AN0

VSS

VDD

RA4/T0CKI

RA5/AN4/C2INA

RC1/T1OSI/ECCP2(1)/P2A(1)

RC0/T1OSO/T13CKI

RC7/RX1/DT1

RC6/TX1/CK1

RC5/SDO1/C2OUT

Note 1: The ECCP2/P2A pin placement depends on the setting of the CCP2MX Configuration bit.

PIC18F87J50 FAMILY

Pin Diagrams (Continued)

80-Pin TQFP

PIC18F8XJ5X

RE2/AD10/PMBE(3)/P2B

RE3/AD11/PMA13/P3C(2)/REFO

RE4/AD12/PMA12/P3B(2)

RE5/AD13/PMA11/P1C(2)

RE6/AD14/PMA10/P1B(2)

RE7/AD15/PMA9/ECCP2(1)/P2A(1)

RD0/AD0/PMD0

VDD

VSS

RD1/AD1/PMD1(3)

RD2/AD2/PMD2(3)

RD3/AD3/PMD3(3)

RD4/AD4/PMD4(3)/SDO2

RD5/AD5/PMD5(3)/SDI2/SDA2

RD6/AD6/PMD6(3)/SCK2/SCL2

RD7/AD7/PMD7(3)/SS2

RE1/AD9/PMWR(3)/P2C

RE0/AD8/PMRD(3)/P2D

RG0/PMA8/ECCP3/P3A

RG1/PMA7/TX2/CK2

RG2/PMA6/RX2/DT2

RG3/PMCS1/CCP4/P3D

MCLR

RG4/PMCS2/CCP5/P1D

VSS

VDDCORE/VCAP

RF7/PMD0(4)/SS1/C1OUT

RB0/FLT0/INT0

RB1/INT1/PMA4

RB2/INT2/PMA3

RB3/INT3/ECCP2(1)/

RB4/KBI0/PMA1

RB5/KBI1/PMA0

RB6/KBI2/PGC

VSS

OSC2/CLKO/RA6

OSC1/CLKI/RA7

VDD

RB7/KBI3/PGD

RC4/SDI1/SDA1

RC3/SCK1/SCL1

RC2/ECCP1/P1A

ENVREG

VUSB

AVDD

AVSS

RA3/AN3/VREF+

RA2/AN2/VREF-

RA1/AN1

RA0/AN0

VSS

VDD

RA4/PMD5(4)/T0CKI

RA5/PMD4(4)/AN4/C2INA

RC1/T1OSI/ECCP2(1)/P2A(1)

RC0/T1OSO/T13CKI

RC7/RX1/DT1

RC6/TX1/CK1

RC5/SDO1/C2OUT

RJ0/ALE

RJ1/OE

RH1/A17

RH0/A16

RH2/A18/PMD7(4)

RH3/A19/PMD6(4)

RH7/PMWR(4)/AN15/P1B(2)

RH6/PMRD(4)/AN14/

RH5/PMBE(4)/AN13/P3B(2)/C2IND

RH4/PMD3(4)/AN12/P3C(2)/C2INC

RJ5/CE

RJ4/BA0

RJ7/UB

RJ6/LB

RJ2/WRL

RJ3/WRH

Note 1: The ECCP2/P2A pin placement depends on the setting of the CCP2MX Configuration bit and the program memory mode.

2: P1B, P1C, P3B and P3C pin placement depends on the setting of the ECCPMX Configuration bit.

3: PMP pin placement when PMPMX = 1.

4: PMP pin placement when PMPMX = 0.

RF5/PMD2(4)/AN10/

RF4/D+

RF3/D-

RF2/PMA5/AN7/C2INB

RF6/PMD1(4)/AN11/C1INA

C1INB/CVREF

P1C(2)/C1INC

P2A(1)/PMA2

PIC18F87J50 FAMILY

Table of Contents

1.0 Device Overview .......................................................................................................................................................................... 9

2.0 Oscillator Configurations ............................................................................................................................................................ 35

3.0 Power-Managed Modes ............................................................................................................................................................. 47

4.0 Reset .......................................................................................................................................................................................... 55

5.0 Memory Organization ................................................................................................................................................................. 69

6.0 Flash Program Memory.............................................................................................................................................................. 97

7.0 External Memory Bus ............................................................................................................................................................... 107

8.0 8 x 8 Hardware Multiplier.......................................................................................................................................................... 119

9.0 Interrupts .................................................................................................................................................................................. 121

10.0 I/O Ports ................................................................................................................................................................................... 137

11.0 Parallel Master Port.................................................................................................................................................................. 167

12.0 Timer0 Module ......................................................................................................................................................................... 191

13.0 Timer1 Module ......................................................................................................................................................................... 195

14.0 Timer2 Module ......................................................................................................................................................................... 201

15.0 Timer3 Module ......................................................................................................................................................................... 203

16.0 Timer4 Module ......................................................................................................................................................................... 207

17.0 Capture/Compare/PWM (CCP) Modules ................................................................................................................................. 209

18.0 Enhanced Capture/Compare/PWM (ECCP) Module................................................................................................................ 217

19.0 Master Synchronous Serial Port (MSSP) Module .................................................................................................................... 233

20.0 Enhanced Universal Synchronous Asynchronous Receiver Transmitter (EUSART) ............................................................... 279

21.0 10-bit Analog-to-Digital Converter (A/D) Module ...................................................................................................................... 301

22.0 Universal Serial Bus (USB) ...................................................................................................................................................... 311

23.0 Comparator Module.................................................................................................................................................................. 337

24.0 Comparator Voltage Reference Module................................................................................................................................... 345

25.0 Special Features of the CPU.................................................................................................................................................... 349

26.0 Instruction Set Summary .......................................................................................................................................................... 365

27.0 Development Support............................................................................................................................................................... 415

28.0 Electrical Characteristics .......................................................................................................................................................... 419

29.0 Packaging Information.............................................................................................................................................................. 459

Appendix A: Revision History............................................................................................................................................................. 463

Appendix B: Device Differences......................................................................................................................................................... 463

The Microchip Web Site..................................................................................................................................................................... 477

Customer Change Notification Service .............................................................................................................................................. 477

Customer Support .............................................................................................................................................................................. 477

Reader Response .............................................................................................................................................................................. 478

Product Identification System............................................................................................................................................................. 479

PIC18F87J50 FAMILY

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It is our intention to provide our valued customers with the best documentation possible to ensure successful use of your Microchip

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If you have any questions or comments regarding this publication, please contact the Marketing Communications Department via

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welcome your feedback.

Most Current Data Sheet

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You can determine the version of a data sheet by examining its literature number found on the bottom outside corner of any page.

The last character of the literature number is the version number, (e.g., DS30000A is version A of document DS30000).

Errata

An errata sheet, describing minor operational differences from the data sheet and recommended workarounds, may exist for current

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of silicon and revision of document to which it applies.

To determine if an errata sheet exists for a particular device, please check with one of the following:

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• Your local Microchip sales office (see last page)

When contacting a sales office, please specify which device, revision of silicon and data sheet (include literature number) you are

using.

Customer Notification System

PIC18F87J50 FAMILY

NOTES:

PIC18F87J50 FAMILY

1.0 DEVICE OVERVIEW

This document contains device-specific information for

the following devices:

This family introduces a new line of low-voltage USB

microcontrollers with the main traditional advantage of

all PIC18 microcontrollers – namely, high computa-

tional performance and a rich feature set – at an

extremely competitive price point. These features

make the PIC18F87J10 family a logical choice for

many high-performance applications, where cost is a

primary consideration.

1.1 Core Features

1.1.1 nanoWatt TECHNOLOGY

All of the devices in the PIC18F87J10 family incorporate

a range of features that can significantly reduce power

consumption during operation. Key items include:

•Alternate Run Modes: By clocking the controller

from the Timer1 source or the internal RC oscilla-

tor, power consumption during code execution

can be reduced by as much as 90%.

•Multiple Idle Modes: The controller can also run

with its CPU core disabled but the peripherals still

active. In these states, power consumption can be

reduced even further, to as little as 4% of normal

operation requirements.

•On-the-Fly Mode Switching: The

power-managed modes are invoked by user code

during operation, allowing the user to incorporate

power-saving ideas into their application’s

software design.

1.1.2 UNIVERSAL SERIAL BUS (USB)

Devices in the PIC18F87J10 family incorporate a

fully-featured Universal Serial Bus communications

module with a built-in transceiver that is compliant with

the USB Specification Revision 2.0. The module

supports both low-speed and full-speed communication

for all supported data transfer types.

1.1.3 OSCILLATOR OPTIONS AND

FEATURES

All of the devices in the PIC18F87J10 family offer five

different oscillator options, allowing users a range of

choices in developing application hardware. These

include:

• Two Crystal modes, using crystals or ceramic

resonators.

• Two External Clock modes, offering the option of

a divide-by-4 clock output.

• An internal oscillator block which provides an

8 MHz clock and an INTRC source (approxi-

mately 31 kHz, stable over temperature and VDD),

as well as a range of 6 user-selectable clock

frequencies, between 125 kHz to 4 MHz, for a

total of 8 clock frequencies. This option frees an

oscillator pin for use as an additional general

purpose I/O.

• A Phase Lock Loop (PLL) frequency multiplier,

available to the high-speed crystal, external

oscillator and internal oscillator, providing a clock

speed up to 48 MHz.

• Dual clock operation, allowing the USB module to

run from a high-frequency oscillator while the rest

of the microcontroller is clocked at a different

frequency.

The internal oscillator block provides a stable reference

source that gives the family additional features for

robust operation:

•Fail-Safe Clock Monitor: This option constantly

monitors the main clock source against a reference

signal provided by the internal oscillator. If a clock

failure occurs, the controller is switched to the

internal oscillator, allowing for continued low-speed

operation or a safe application shutdown.

•Two-Speed Start-up: This option allows the

internal oscillator to serve as the clock source

from Power-on Reset, or wake-up from Sleep

mode, until the primary clock source is available.

1.1.4 EXPANDED MEMORY

The PIC18F87J10 family provides ample room for

application code, from 32 Kbytes to 128 Kbytes of code

space. The Flash cells for program memory are rated

to last in excess of 10000 erase/write cycles. Data

retention without refresh is conservatively estimated to

be greater than 20 years.

The Flash program memory is readable and writable

during normal operation. The PIC18F87J10 family also

provides plenty of room for dynamic application data

with up to 3904 bytes of data RAM.

• PIC18F65J50 • PIC18F85J50

• PIC18F66J50 • PIC18F86J50

• PIC18F66J55 • PIC18F86J55

• PIC18F67J50 • PIC18F87J50

PIC18F87J50 FAMILY

1.1.5 EXTERNAL MEMORY BUS

In the event that 128 Kbytes of memory are inadequate

for an application, the 80-pin members of the

PIC18F87J10 family also implement an External Mem-

ory Bus (EMB). This allows the controller’s internal

program counter to address a memory space of up to

2 Mbytes, permitting a level of data access that few

8-bit devices can claim. This allows additional memory

options, including:

• Using combinations of on-chip and external

memory up to the 2-Mbyte limit

• Using external Flash memory for reprogrammable

application code or large data tables

• Using external RAM devices for storing large

amounts of variable data

1.1.6 EXTENDED INSTRUCTION SET

The PIC18F87J10 family implements the optional

extension to the PIC18 instruction set, adding 8 new

instructions and an Indexed Addressing mode.

Enabled as a device configuration option, the extension

has been specifically designed to optimize re-entrant

application code originally developed in high-level

languages, such as ‘C’.

1.1.7 EASY MIGRATION

Regardless of the memory size, all devices share the

same rich set of peripherals, allowing for a smooth

migration path as applications grow and evolve.

The consistent pinout scheme used throughout the

entire family also aids in migrating to the next larger

device. This is true when moving between the 64-pin

members, between the 80-pin members, or even

jumping from 64-pin to 80-pin devices.

The PIC18F87J10 family is also pin compatible with

other PIC18 families, such as the PIC18F87J10,

PIC18F87J11, PIC18F8720 and PIC18F8722. This

allows a new dimension to the evolution of applications,

allowing developers to select different price points

within Microchip’s PIC18 portfolio, while maintaining

the same feature set.

1.2 Other Special Features

•Communications: The PIC18F87J10 family

incorporates a range of serial and parallel com-

munication peripherals, including a fully featured

Universal Serial Bus communications module that

is compliant with the USB Specification

Revision 2.0. This device also includes 2 indepen-

dent Enhanced USARTs and 2 Master SSP

modules, capable of both SPI and I2C™ (Master

and Slave) modes of operation. The device also

has a parallel port and can be configured to serve

as either a Parallel Master Port or as a Parallel

Slave Port.

•CCP Modules: All devices in the family incorporate

two Capture/Compare/PWM (CCP) modules and

three Enhanced CCP modules to maximize

flexibility in control applications. Up to four different

time bases may be used to perform several

different operations at once. Each of the three

ECCPs offers up to four PWM outputs, allowing for

a total of 12 PWMs. The ECCPs also offer many

beneficial features, including polarity selection,

programmable dead time, auto-shutdown and

restart and Half-Bridge and Full-Bridge Output

modes.

•10-Bit A/D Converter: This module incorporates

programmable acquisition time, allowing for a

channel to be selected and a conversion to be

initiated without waiting for a sampling period, and

thus, reducing code overhead.

•Extended Watchdog Timer (WDT): This

enhanced version incorporates a 16-bit prescaler,

allowing an extended time-out range that is stable

across operating voltage and temperature. See

Section 28.0 “Electrical Characteristics” for

time-out periods.

1.3 Details on Individual Family

Members

Devices in the PIC18F87J10 family are available in

64-pin and 80-pin packages. Block diagrams for the

two groups are shown in Figure 1-1 and Figure 1-2.

The devices are differentiated from each other in two

ways:

1. Flash program memory (six sizes, ranging from

32 Kbytes for PIC18FX5J50 devices to

128 Kbytes for PIC18FX7J50).

2. I/O ports (7 bidirectional ports on 64-pin devices,

9 bidirectional ports on 80-pin devices).

All other features for devices in this family are identical.

These are summarized in Table 1-1 and Table 1-2.

The pinouts for all devices are listed in Table 1-3 and

Table 1-4.

PIC18F87J50 FAMILY

TABLE 1-1: DEVICE FEATURES FOR THE PIC18F6XJ5X (64-PIN DEVICES)

TABLE 1-2: DEVICE FEATURES FOR THE PIC18F8XJ5X (80-PIN DEVICES)

Features PIC18F65J50 PIC18F66J50 PIC18F66J55 PIC18F67J50

Operating Frequency DC – 48 MHz DC – 48 MHz DC – 48 MHz DC – 48 MHz

Program Memory (Bytes) 32K 64K 96K 128K

Program Memory (Instructions) 16384 32768 49152 65536

Data Memory (Bytes) 3904 3904 3904 3904

Interrupt Sources 30

I/O Ports Ports A, B, C, D, E, F, G

Timers 5

Capture/Compare/PWM Modules 2

Enhanced Capture/

Compare/PWM Modules

Serial Communications MSSP (2), Enhanced USART (2), USB

Parallel Communications (PMP) Yes

10-Bit Analog-to-Digital Module 8 Input Channels

Resets (and Delays) POR, BOR, RESET Instruction, Stack Full, Stack Underflow, MCLR, WDT

(PWRT, OST)

Instruction Set 75 Instructions, 83 with Extended Instruction Set Enabled

Packages 64-Pin TQFP

Features PIC18F85J50 PIC18F86J50 PIC18F86J55 PIC18F87J50

Operating Frequency DC – 48 MHz DC – 48 MHz DC – 48 MHz DC – 48 MHz

Program Memory (Bytes) 32K 64K 96K 128K

Program Memory (Instructions) 16384 32768 49152 65536

Data Memory (Bytes) 3904 3904 3904 3904

Interrupt Sources 30

I/O Ports Ports A, B, C, D, E, F, G, H, J

Timers 5

Capture/Compare/PWM Modules 2

Enhanced Capture/

Compare/PWM Modules

Serial Communications MSSP (2), Enhanced USART (2), USB

Parallel Communications (PMP) Yes

10-Bit Analog-to-Digital Module 12 Input Channels

Resets (and Delays) POR, BOR, RESET Instruction, Stack Full, Stack Underflow, MCLR, WDT

(PWRT, OST)

Instruction Set 75 Instructions, 83 with Extended Instruction Set Enabled

Packages 80-Pin TQFP

PIC18F87J50 FAMILY

FIGURE 1-1: PIC18F6XJ5X (64-PIN) BLOCK DIAGRAM

Instruction

Decode and

Control

PORTA

Data Latch

Data Memory

(3.9 Kbytes)

Address Latch

Data Address<12>

Access

BSR FSR0

FSR1

FSR2

inc/dec

logic

Address

412 4

PCH PCL

PCLATH

31 Level Stack

Program Counter

PRODLPRODH

8 x 8 Multiply

BITOP

ALU<8>

Address Latch

Program Memory

(32-128 Kbytes)

Data Latch

Table Pointer<21>

inc/dec logic

Data Bus<8>

Table Latch

PCLATU

PCU

Note 1: See Table 1-3 for I/O port pin descriptions.

2: BOR functionality is provided when the on-board voltage regulator is enabled.

EUSART1

Comparators

MSSP1

Timer2Timer1 Timer3Timer0

ECCP1

ADC

10-Bit

Instruction Bus <16>

STKPTR Bank

State Machine

Control Signals

Decode

EUSART2

ECCP2

ROM Latch

ECCP3 MSSP2CCP4 CCP5

PORTC

PORTD

PORTE

PORTF

PORTG

RA0:RA5(1)

RC0:RC7(1)

RD0:RD7(1)

RE0:RE7(1)

RF2:RF7(1)

RG0:RG4(1)

PORTB

RB0:RB7(1)

Timer4

OSC1/CLKI

OSC2/CLKO

VDD,

8 MHz

INTOSC

VSS MCLR

Power-up

Timer

Oscillator

Start-up Timer

Power-on

Reset

Watchdog

Timer

Brown-out

Reset(2)

Precision

Reference

Band Gap

INTRC

Oscillator

Regulator

Voltage

VDDCORE/VCAP

ENVREG

USB

PMP

Timing

Generation

USB

Module

VUSB

PIC18F87J50 FAMILY

FIGURE 1-2: PIC18F8XJ5X (80-PIN) BLOCK DIAGRAM

PRODLPRODH

8 x 8 Multiply

BITOP

ALU<8>

Instruction

Decode &

Control

Data Latch

Address Latch

Data Address<12>

Access

BSR FSR0

FSR1

FSR2

inc/dec

logic

Address

412 4

PCH PCL

PCLATH

31 Level Stack

Program Counter

Address Latch

Program Memory

(32-128 Kbytes)

Data Latch

Table Pointer<21>

inc/dec logic

Data Bus<8>

Tab l e Latch

ROM Latch

PCLATU

PCU

Instruction Bus <16>

STKPTR Bank

State Machine

Control Signals

Decode

System Bus Interface

AD15:AD0, A19:A16

(Multiplexed with PORTD,

PORTE and PORTH)

PORTA

PORTC

PORTD

PORTE

PORTF

PORTG

RA0:RA5(1)

RC0:RC7(1)

RD0:RD7(1)

RE0:RE7(1)

RF2:RF7(1)

RG0:RG4(1)

PORTB

RB0:RB7(1)

PORTH

RH0:RH7(1)

PORTJ

RJ0:RJ7(1)

EUSART1

Comparators

MSSP1

Timer2Timer1 Timer3Timer0

ECCP1

ADC

10-Bit

EUSART2

ECCP2 ECCP3 MSSP2CCP4 CCP5

Timer4

Note 1: See Table 1-4 for I/O port pin descriptions.

2: BOR functionality is provided when the on-board voltage regulator is enabled.

Data Memory

(3.9 Kbytes)

USB

PMP

OSC1/CLKI

OSC2/CLKO

VDD,

8 MHz

INTOSC

VSS MCLR

Power-up

Timer

Oscillator

Start-up Timer

Power-on

Reset

Watchdog

Timer

Brown-out

Reset(2)

Precision

Reference

Band Gap

INTRC

Oscillator

Regulator

Voltage

VDDCORE/VCAP

ENVREG

Timing

Generation

USB

Module

VUSB

PIC18F87J50 FAMILY

TABLE 1-3: PIC18F6XJ5X PINOUT I/O DESCRIPTIONS

Pin Name

Pin Number Pin

Type

Buffer

Type Description

64-TQFP

MCLR 7 I ST Master Clear (Reset) input. This pin is an active-low Reset

to the device.

OSC1/CLKI/RA7

OSC1

CLKI

RA7(3)

I/O

CMOS

TTL

Oscillator crystal or external clock input.

Oscillator crystal input or external clock source input.

ST buffer when configured in RC mode; CMOS

otherwise.

Main oscillator input connection.

External clock source input. Always associated

with pin function OSC1. (See related OSC1/CLKI,

OSC2/CLKO pins.)

Main clock input connection.

General purpose I/O pin.

OSC2/CLKO/RA6

OSC2

CLKO

RA6(3)

I/O

—

TTL

Oscillator crystal or clock output.

Oscillator crystal output. Connects to crystal or

resonator in Crystal Oscillator mode.

Main oscillator feedback output connection.

In RC mode, OSC2 pin outputs CLKO which has

1/4 the frequency of OSC1 and denotes the

instruction cycle rate.

System cycle clock output (FOSC/4).

General purpose I/O pin.

Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output

ST = Schmitt Trigger input with CMOS levels Analog = Analog input

I = Input O = Output

P = Power OD = Open-Drain (no P diode to VDD)

Note 1: Default assignment for ECCP2/P2A when CCP2MX Configuration bit is set.

2: Alternate assignment for ECCP2/P2A when CCP2MX Configuration bit is cleared.

3: RA7 and RA6 will be disabled if OSC1 and OSC2 are used for the clock function.

PIC18F87J50 FAMILY

PORTA is a bidirectional I/O port.

RA0/AN0

RA0

AN0

I/O

TTL

Analog

Digital I/O.

Analog input 0.

RA1/AN1

RA1

AN1

I/O

TTL

Analog

Digital I/O.

Analog input 1.

RA2/AN2/VREF-

RA2

AN2

VREF-

I/O

TTL

Analog

Digital I/O.

Analog input 2.

A/D reference voltage (low) input.

RA3/AN3/VREF+

RA3

AN3

VREF+

I/O

TTL

Analog

Digital I/O.

Analog input 3.

A/D reference voltage (high) input.

RA4/T0CKI

RA4

T0CKI

I/O

Digital I/O.

Timer0 external clock input.

RA5/AN4/C2INA

RA5

AN4

C2INA

I/O

—

TTL

Analog

Digital I/O.

Analog input 4.

Comparator 2 input A

RA6

RA7

—

See the OSC2/CLKO/RA6 pin.

See the OSC1/CLKI/RA7 pin.

TABLE 1-3: PIC18F6XJ5X PINOUT I/O DESCRIPTIONS (CONTINUED)

Pin Name

Pin Number Pin

Type

Buffer

Type Description

64-TQFP

Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output

ST = Schmitt Trigger input with CMOS levels Analog = Analog input

I = Input O = Output

P = Power OD = Open-Drain (no P diode to VDD)

Note 1: Default assignment for ECCP2/P2A when CCP2MX Configuration bit is set.

2: Alternate assignment for ECCP2/P2A when CCP2MX Configuration bit is cleared.

3: RA7 and RA6 will be disabled if OSC1 and OSC2 are used for the clock function.

PIC18F87J50 FAMILY

PORTB is a bidirectional I/O port. PORTB can be software

programmed for internal weak pull-ups on all inputs.

RB0/FLT0/INT0

RB0

FLT0

INT0

I/O

TTL

Digital I/O.

ECCP1/2/3 Fault input.

External interrupt 0.

RB1/INT1/PMA4

RB1

INT1

PMA4

I/O

TTL

—

Digital I/O.

External interrupt 1.

Parallel Master Port address.

RB2/INT2/PMA3

RB2

INT2

PMA3

I/O

TTL

—

Digital I/O.

External interrupt 2.

Parallel Master Port address.

RB3/INT3/PMA2

RB3

INT3

PMA2

I/O

TTL

—

Digital I/O.

External interrupt 3.

Parallel Master Port address.

RB4/KBI0/PMA1

RB4

KBI0

PMA1

I/O

TTL

—

Digital I/O.

Interrupt-on-change pin.

Parallel Master Port address.

RB5/KBI1/PMA0

RB5

KBI1

PMA0

I/O

TTL

—

Digital I/O.

Interrupt-on-change pin.

Parallel Master Port address.

RB6/KBI2/PGC

RB6

KBI2

PGC

I/O

TTL

Digital I/O.

Interrupt-on-change pin.

In-Circuit Debugger and ICSP™ programming clock pin.

RB7/KBI3/PGD

RB7

KBI3

PGD

I/O

TTL

Digital I/O.

Interrupt-on-change pin.

In-Circuit Debugger and ICSP programming data pin.

TABLE 1-3: PIC18F6XJ5X PINOUT I/O DESCRIPTIONS (CONTINUED)

Pin Name

Pin Number Pin

Type

Buffer

Type Description

64-TQFP

Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output

ST = Schmitt Trigger input with CMOS levels Analog = Analog input

I = Input O = Output

P = Power OD = Open-Drain (no P diode to VDD)

Note 1: Default assignment for ECCP2/P2A when CCP2MX Configuration bit is set.

2: Alternate assignment for ECCP2/P2A when CCP2MX Configuration bit is cleared.

3: RA7 and RA6 will be disabled if OSC1 and OSC2 are used for the clock function.

PIC18F87J50 FAMILY

PORTC is a bidirectional I/O port.

RC0/T1OSO/T13CKI

RC0

T1OSO

T13CKI

I/O

—

Digital I/O.

Timer1 oscillator output.

Timer1/Timer3 external clock input.

RC1/T1OSI/ECCP2/P2A

RC1

T1OSI

ECCP2(1)

P2A(1)

I/O

CMOS

—

Digital I/O.

Timer1 oscillator input.

Capture 2 input/Compare 2 output/PWM2 output.

ECCP2 PWM output A.

RC2/ECCP1/P1A

RC2

ECCP1

P1A

I/O

—

Digital I/O.

Capture 1 input/Compare 1 output/PWM1 output.

ECCP1 PWM output A.

RC3/SCK1/SCL1

RC3

SCK1

SCL1

I/O

Digital I/O.

Synchronous serial clock input/output for SPI mode.

Synchronous serial clock input/output for I2C™ mode.

RC4/SDI1/SDA1

RC4

SDI1

SDA1

I/O

Digital I/O.

SPI data in.

I2C data I/O.

RC5/SDO1/C2OUT

RC5

SDO1

C2OUT

I/O

—

TTL

Digital I/O.

SPI data out.

Comparator 2 output.

RC6/TX1/CK1

RC6

TX1

CK1

I/O

—

Digital I/O.

EUSART1 asynchronous transmit.

EUSART1 synchronous clock (see related RX1/DT1).

RC7/RX1/DT1

RC7

RX1

DT1

I/O

Digital I/O.

EUSART1 asynchronous receive.

EUSART1 synchronous data (see related TX1/CK1).

TABLE 1-3: PIC18F6XJ5X PINOUT I/O DESCRIPTIONS (CONTINUED)

Pin Name

Pin Number Pin

Type

Buffer

Type Description

64-TQFP

Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output

ST = Schmitt Trigger input with CMOS levels Analog = Analog input

I = Input O = Output

P = Power OD = Open-Drain (no P diode to VDD)

Note 1: Default assignment for ECCP2/P2A when CCP2MX Configuration bit is set.

2: Alternate assignment for ECCP2/P2A when CCP2MX Configuration bit is cleared.

3: RA7 and RA6 will be disabled if OSC1 and OSC2 are used for the clock function.

PIC18F87J50 FAMILY

PORTD is a bidirectional I/O port.

RD0/PMD0

RD0

PMD0

I/O

TTL

Digital I/O.

Parallel Master Port data.

RD1/PMD1

RD1

PMD1

I/O

TTL

Digital I/O.

Parallel Master Port data.

RD2/PMD2

RD2

PMD2

I/O

TTL

Digital I/O.

Parallel Master Port data.

RD3/PMD3

RD3

PMD3

I/O

TTL

Digital I/O.

Parallel Master Port data.

RD4/PMD4/SDO2

RD4

PMD4

SDO2

I/O

TTL

—

Digital I/O.

Parallel Master Port data.

SPI data out.

RD5/PMD5/SDI2/SDA2

RD5

PMD5

SDI2

SDA2

I/O

TTL

Digital I/O.

Parallel Master Port data.

SPI data in.

I2C™ data I/O.

RD6/PMD6/SCK2/SCL2

RD6

PMD6

SCK2

SCL2

I/O

TTL

Digital I/O.

Parallel Master Port data.

Synchronous serial clock input/output for SPI mode.

Synchronous serial clock input/output for I2C mode.

RD7/PMD7/SS2

RD7

PMD7

SS2

I/O

TTL

Digital I/O.

Parallel Master Port data.

SPI slave select input.

TABLE 1-3: PIC18F6XJ5X PINOUT I/O DESCRIPTIONS (CONTINUED)

Pin Name

Pin Number Pin

Type

Buffer

Type Description

64-TQFP

Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output

ST = Schmitt Trigger input with CMOS levels Analog = Analog input

I = Input O = Output

P = Power OD = Open-Drain (no P diode to VDD)

Note 1: Default assignment for ECCP2/P2A when CCP2MX Configuration bit is set.

2: Alternate assignment for ECCP2/P2A when CCP2MX Configuration bit is cleared.

3: RA7 and RA6 will be disabled if OSC1 and OSC2 are used for the clock function.

PIC18F87J50 FAMILY

PORTE is a bidirectional I/O port.

RE0/PMRD/P2D

RE0

PMRD

P2D

I/O

—

Digital I/O.

Parallel Master Port read strobe.

ECCP2 PWM output D.

RE1/PMWR/P2C

RE1

PMWR

P2C

I/O

—

Digital I/O.

Parallel Master Port write strobe.

ECCP2 PWM output C.

RE2/PMBE/P2B

RE2

PMBE

P2B

I/O

—

Digital I/O.

Parallel Master Port byte enable

ECCP2 PWM output B.

RE3/PMA13/P3C/REFO

RE3

PMA13

P3C

REFO

I/O

—

Digital I/O.

Parallel Master Port address.

ECCP3 PWM output C.

Reference clock out.

RE4/PMA12/P3B

RE4

PMA12

P3B

I/O

—

Digital I/O.

Parallel Master Port address.

ECCP3 PWM output B.

RE5/PMA11/P1C

RE5

PMA11

P1C

I/O

—

Digital I/O.

Parallel Master Port address.

ECCP1 PWM output C.

RE6/PMA10/P1B

RE6

PMA10

P1B

I/O

—

Digital I/O.

Parallel Master Port address.

ECCP1 PWM output B.

RE7/PMA9/ECCP2/P2A

RE7

PMA9

ECCP2(2)

P2A(2)

I/O

—

Digital I/O.

Parallel Master Port address.

Capture 2 input/Compare 2 output/PWM2 output.

ECCP2 PWM output A.

TABLE 1-3: PIC18F6XJ5X PINOUT I/O DESCRIPTIONS (CONTINUED)

Pin Name

Pin Number Pin

Type

Buffer

Type Description

64-TQFP

Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output

ST = Schmitt Trigger input with CMOS levels Analog = Analog input

I = Input O = Output

P = Power OD = Open-Drain (no P diode to VDD)

Note 1: Default assignment for ECCP2/P2A when CCP2MX Configuration bit is set.

2: Alternate assignment for ECCP2/P2A when CCP2MX Configuration bit is cleared.

3: RA7 and RA6 will be disabled if OSC1 and OSC2 are used for the clock function.

PIC18F87J50 FAMILY

PORTF is a bidirectional I/O port.

RF2/PMA5/AN7/C2INB

RF2

PMA5

AN7

C2INB

I/O

—

Analog

Digital I/O.

Parallel Master Port address.

Analog input 7.

Comparator 2 input B.

RF3/D-

RF3

D-

I/O

—

Digital input.

USB differential minus line (input/output).

RF4/D+

RF4

D+

I/O

—

Digital input.

USB differential plus line (input/output).

RF5/AN10/C1INB/CVREF

RF5

AN10

C1INB

CVREF

Analog

Digital input.

Analog input 10.

Comparator 1 input B.

Comparator reference voltage output.

RF6/AN11/C1INA

RF6

AN11

C1INA

I/O

Analog

Digital I/O.

Analog input 11.

Comparator 1 input A.

RF7/SS1/C1OUT

RF7

SS1

C1OUT

I/O

TTL

Digital I/O.

SPI slave select input.

Comparator 1 output.

TABLE 1-3: PIC18F6XJ5X PINOUT I/O DESCRIPTIONS (CONTINUED)

Pin Name

Pin Number Pin

Type

Buffer

Type Description

64-TQFP

Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output

ST = Schmitt Trigger input with CMOS levels Analog = Analog input

I = Input O = Output

P = Power OD = Open-Drain (no P diode to VDD)

Note 1: Default assignment for ECCP2/P2A when CCP2MX Configuration bit is set.

2: Alternate assignment for ECCP2/P2A when CCP2MX Configuration bit is cleared.

3: RA7 and RA6 will be disabled if OSC1 and OSC2 are used for the clock function.

PIC18F87J50 FAMILY

PORTG is a bidirectional I/O port.

RG0/PMA8/ECCP3/P3A

RG0

PMA8

ECCP3

P3A

I/O

—

Digital I/O.

Parallel Master Port address.

Capture 3 input/Compare 3 output/PWM3 output.

ECCP3 PWM output A.

RG1/PMA7/TX2/CK2

RG1

PMA7

TX2

CK2

I/O

—

Digital I/O.

Parallel Master Port address.

EUSART2 asynchronous transmit.

EUSART2 synchronous clock (see related RX2/DT2).

RG2/PMA6/RX2/DT2

RG2

PMA6

RX2

DT2

I/O

—

Digital I/O.

Parallel Master Port address.

EUSART2 asynchronous receive.

EUSART2 synchronous data (see related TX2/CK2).

RG3/PMCS1/CCP4/P3D

RG3

PMCS1

CCP4

P3D

I/O

—

Digital I/O.

Parallel Master Port chip select 1.

Capture 4 input/Compare 4 output/PWM4 output.

ECCP3 PWM output D.

RG4/PMCS2/CCP5/P1D

RG4

PMCS2

CCP5

P1D

I/O

—

Digital I/O.

Parallel Master Port chip select 2.

Capture 5 input/Compare 5 output/PWM5 output.

ECCP1 PWM output D.

VSS 9, 25, 41, 56 P — Ground reference for logic and I/O pins.

VDD 26, 38, 57 P — Positive supply for peripheral digital logic and I/O pins.

AVSS 20 P — Ground reference for analog modules.

AVDD 19 P — Positive supply for analog modules.

ENVREG 18 I ST Enable for on-chip voltage regulator.

VDDCORE/VCAP

VDDCORE

VCAP

—

Core logic power or external filter capacitor connection.

Positive supply for microcontroller core logic

(regulator disabled).

External filter capacitor connection (regulator

enabled).

VUSB 17 P — USB voltage input pin.

TABLE 1-3: PIC18F6XJ5X PINOUT I/O DESCRIPTIONS (CONTINUED)

Pin Name

Pin Number Pin

Type

Buffer

Type Description

64-TQFP

Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output

ST = Schmitt Trigger input with CMOS levels Analog = Analog input

I = Input O = Output

P = Power OD = Open-Drain (no P diode to VDD)

Note 1: Default assignment for ECCP2/P2A when CCP2MX Configuration bit is set.

2: Alternate assignment for ECCP2/P2A when CCP2MX Configuration bit is cleared.

3: RA7 and RA6 will be disabled if OSC1 and OSC2 are used for the clock function.

PIC18F87J50 FAMILY

TABLE 1-4: PIC18F8XJ5X PINOUT I/O DESCRIPTIONS

Pin Name

Pin Number Pin

Type

Buffer

Type Description

80-TQFP

MCLR 9 I ST Master Clear (Reset) input. This pin is an active-low Reset

to the device.

OSC1/CLKI/RA7

OSC1

CLKI

RA7(8)

I/O

CMOS

TTL

Oscillator crystal or external clock input.

Oscillator crystal input or external clock source input.

ST buffer when configured in RC mode; CMOS

otherwise.

Main oscillator input connection.

External clock source input. Always associated

with pin function OSC1. (See related OSC1/CLKI,

OSC2/CLKO pins.)

Main clock input connection.

General purpose I/O pin.

OSC2/CLKO/RA6

OSC2

CLKO

RA6(8)

I/O

—

TTL

Oscillator crystal or clock output.

Oscillator crystal output. Connects to crystal or

resonator in Crystal Oscillator mode.

Main oscillator feedback output connection.

In RC mode, OSC2 pin outputs CLKO which has

1/4 the frequency of OSC1 and denotes the

instruction cycle rate.

System cycle clock output (FOSC/4).

General purpose I/O pin.

Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output

ST = Schmitt Trigger input with CMOS levels Analog = Analog input

I = Input O = Output

P = Power OD = Open-Drain (no P diode to VDD)

Note 1: Alternate assignment for ECCP2/P2A when CCP2MX Configuration bit is cleared (Extended Microcontroller

mode).

2: Default assignment for ECCP2/P2A for all devices in all operating modes (CCP2MX is set).

3: Default assignments for P1B/P1C/P3B/P3C (ECCPMX Configuration bit is set).

4: Alternate assignment for ECCP2/P2A when CCP2MX is cleared (Microcontroller mode).

5: Alternate assignments for P1B/P1C/P3B/P3C (ECCPMX Configuration bit is cleared).

6: Pin placement when PMPMX = 1.

7: Pin placement when PMPMX = 0.

8: RA7 and RA6 will be disabled if OSC1 and OSC2 are used for the clock function.

PIC18F87J50 FAMILY

PORTA is a bidirectional I/O port.

RA0/AN0

RA0

AN0

I/O

TTL

Analog

Digital I/O.

Analog input 0.

RA1/AN1

RA1

AN1

I/O

TTL

Analog

Digital I/O.

Analog input 1.

RA2/AN2/VREF-

RA2

AN2

VREF-

I/O

TTL

Analog

Digital I/O.

Analog input 2.

A/D reference voltage (low) input.

RA3/AN3/VREF+

RA3

AN3

VREF+

I/O

TTL

Analog

Digital I/O.

Analog input 3.

A/D reference voltage (high) input.

RA4/PMD5/T0CKI

RA4

PMD5(7)

T0CKI

I/O

TTL

Digital I/O.

Parallel Master Port data.

Timer0 external clock input.

RA5/PMD4/AN4/C2INA

RA5

PMD4(7)

AN4

C2INA

I/O

TTL

Analog

Digital I/O.

Parallel Master Port data.

Analog input 4.

Comparator 2 input A.

RA6

RA7

—

See the OSC2/CLKO/RA6 pin.

See the OSC1/CLKI/RA7 pin.

TABLE 1-4: PIC18F8XJ5X PINOUT I/O DESCRIPTIONS (CONTINUED)

Pin Name

Pin Number Pin

Type

Buffer

Type Description

80-TQFP

Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output

ST = Schmitt Trigger input with CMOS levels Analog = Analog input

I = Input O = Output

P = Power OD = Open-Drain (no P diode to VDD)

Note 1: Alternate assignment for ECCP2/P2A when CCP2MX Configuration bit is cleared (Extended Microcontroller

mode).

2: Default assignment for ECCP2/P2A for all devices in all operating modes (CCP2MX is set).

3: Default assignments for P1B/P1C/P3B/P3C (ECCPMX Configuration bit is set).

4: Alternate assignment for ECCP2/P2A when CCP2MX is cleared (Microcontroller mode).

5: Alternate assignments for P1B/P1C/P3B/P3C (ECCPMX Configuration bit is cleared).

6: Pin placement when PMPMX = 1.

7: Pin placement when PMPMX = 0.

8: RA7 and RA6 will be disabled if OSC1 and OSC2 are used for the clock function.

PIC18F87J50 FAMILY

PORTB is a bidirectional I/O port. PORTB can be software

programmed for internal weak pull-ups on all inputs.

RB0/FLT0/INT0

RB0

FLT0

INT0

I/O

TTL

Digital I/O.

ECCP1/2/3 Fault input.

External interrupt 0.

RB1/INT1/PMA4

RB1

INT1

PMA4

I/O

TTL

—

Digital I/O.

External interrupt 1.

Parallel Master Port address.

RB2/INT2/PMA3

RB2

INT2

PMA3

I/O

TTL

—

Digital I/O.

External interrupt 2.

Parallel Master Port address.

RB3/INT3/ECCP2/

P2A/PMA2

RB3

INT3

ECCP2(1)

P2A(1)

PMA2

I/O

TTL

—

Digital I/O.

External interrupt 3.

Capture 2 input/Compare 2 output/PWM2 output.

ECCP2 PWM output A.

Parallel Master Port address.

RB4/KBI0/PMA1

RB4

KBI0

PMA1

I/O

TTL

—

Digital I/O.

Interrupt-on-change pin.

Parallel Master Port address.

RB5/KBI1/PMA0

RB5

KBI1

PMA0

I/O

TTL

—

Digital I/O.

Interrupt-on-change pin.

Parallel Master Port address.

RB6/KBI2/PGC

RB6

KBI2

PGC

I/O

TTL

Digital I/O.

Interrupt-on-change pin.

In-Circuit Debugger and ICSP™ programming clock pin.

RB7/KBI3/PGD

RB7

KBI3

PGD

I/O

TTL

Digital I/O.

Interrupt-on-change pin.

In-Circuit Debugger and ICSP programming data pin.

TABLE 1-4: PIC18F8XJ5X PINOUT I/O DESCRIPTIONS (CONTINUED)

Pin Name

Pin Number Pin

Type

Buffer

Type Description

80-TQFP

Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output

ST = Schmitt Trigger input with CMOS levels Analog = Analog input

I = Input O = Output

P = Power OD = Open-Drain (no P diode to VDD)

Note 1: Alternate assignment for ECCP2/P2A when CCP2MX Configuration bit is cleared (Extended Microcontroller

mode).

2: Default assignment for ECCP2/P2A for all devices in all operating modes (CCP2MX is set).

3: Default assignments for P1B/P1C/P3B/P3C (ECCPMX Configuration bit is set).

4: Alternate assignment for ECCP2/P2A when CCP2MX is cleared (Microcontroller mode).

5: Alternate assignments for P1B/P1C/P3B/P3C (ECCPMX Configuration bit is cleared).

6: Pin placement when PMPMX = 1.

7: Pin placement when PMPMX = 0.

8: RA7 and RA6 will be disabled if OSC1 and OSC2 are used for the clock function.

PIC18F87J50 FAMILY

PORTC is a bidirectional I/O port.

RC0/T1OSO/T13CKI

RC0

T1OSO

T13CKI

I/O

—

Digital I/O.

Timer1 oscillator output.

Timer1/Timer3 external clock input.

RC1/T1OSI/ECCP2/P2A

RC1

T1OSI

ECCP2(2)

P2A(2)

I/O

CMOS

—

Digital I/O.

Timer1 oscillator input.

Capture 2 input/Compare 2 output/PWM2 output.

ECCP2 PWM output A.

RC2/ECCP1/P1A

RC2

ECCP1

P1A

I/O

—

Digital I/O.

Capture 1 input/Compare 1 output/PWM1 output.

ECCP1 PWM output A.

RC3/SCK1/SCL1

RC3

SCK1

SCL1

I/O

Digital I/O.

Synchronous serial clock input/output for SPI mode.

Synchronous serial clock input/output for I2C™ mode.

RC4/SDI1/SDA1

RC4

SDI1

SDA1

I/O

Digital I/O.

SPI data in.

I2C data I/O.

RC5/SDO1/C2OUT

RC5

SDO1

C2OUT

I/O

—

TTL

Digital I/O.

SPI data out.

Comparator 2 output.

RC6/TX1/CK1

RC6

TX1

CK1

I/O

—

Digital I/O.

EUSART1 asynchronous transmit.

EUSART1 synchronous clock (see related RX1/DT1).

RC7/RX1/DT1

RC7

RX1

DT1

I/O

Digital I/O.

EUSART1 asynchronous receive.

EUSART1 synchronous data (see related TX1/CK1).

TABLE 1-4: PIC18F8XJ5X PINOUT I/O DESCRIPTIONS (CONTINUED)

Pin Name

Pin Number Pin

Type

Buffer

Type Description

80-TQFP

Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output

ST = Schmitt Trigger input with CMOS levels Analog = Analog input

I = Input O = Output

P = Power OD = Open-Drain (no P diode to VDD)

Note 1: Alternate assignment for ECCP2/P2A when CCP2MX Configuration bit is cleared (Extended Microcontroller

mode).

2: Default assignment for ECCP2/P2A for all devices in all operating modes (CCP2MX is set).

3: Default assignments for P1B/P1C/P3B/P3C (ECCPMX Configuration bit is set).

4: Alternate assignment for ECCP2/P2A when CCP2MX is cleared (Microcontroller mode).

5: Alternate assignments for P1B/P1C/P3B/P3C (ECCPMX Configuration bit is cleared).

6: Pin placement when PMPMX = 1.

7: Pin placement when PMPMX = 0.

8: RA7 and RA6 will be disabled if OSC1 and OSC2 are used for the clock function.

PIC18F87J50 FAMILY

PORTD is a bidirectional I/O port.

RD0/AD0/PMD0

RD0

AD0

PMD0(6)

I/O

TTL

Digital I/O.

External memory address/data 0.

Parallel Master Port data.

RD1/AD1/PMD1

RD1

AD1

PMD1(6)

I/O

TTL

Digital I/O.

External memory address/data 1.

Parallel Master Port data.

RD2/AD2/PMD2

RD2

AD2

PMD2(6)

I/O

TTL

Digital I/O.

External memory address/data 2.

Parallel Master Port data.

RD3/AD3/PMD3

RD3

AD3

PMD3(6)

I/O

TTL

Digital I/O.

External memory address/data 3.

Parallel Master Port data.

RD4/AD4/PMD4/

SDO2

RD4

AD4

PMD4(6)

SDO2

I/O

TTL

—

Digital I/O.

External memory address/data 4.

Parallel Master Port data.

SPI data out.

RD5/AD5/PMD5/

SDI2/SDA2

RD5

AD5

PMD5(6)

SDI2

SDA2

I/O

TTL

Digital I/O.

External memory address/data 5.

Parallel Master Port data.

SPI data in.

I2C™ data I/O.

TABLE 1-4: PIC18F8XJ5X PINOUT I/O DESCRIPTIONS (CONTINUED)

Pin Name

Pin Number Pin

Type

Buffer

Type Description

80-TQFP

Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output

ST = Schmitt Trigger input with CMOS levels Analog = Analog input

I = Input O = Output

P = Power OD = Open-Drain (no P diode to VDD)

Note 1: Alternate assignment for ECCP2/P2A when CCP2MX Configuration bit is cleared (Extended Microcontroller

mode).

2: Default assignment for ECCP2/P2A for all devices in all operating modes (CCP2MX is set).

3: Default assignments for P1B/P1C/P3B/P3C (ECCPMX Configuration bit is set).

4: Alternate assignment for ECCP2/P2A when CCP2MX is cleared (Microcontroller mode).

5: Alternate assignments for P1B/P1C/P3B/P3C (ECCPMX Configuration bit is cleared).

6: Pin placement when PMPMX = 1.

7: Pin placement when PMPMX = 0.

8: RA7 and RA6 will be disabled if OSC1 and OSC2 are used for the clock function.

PIC18F87J50 FAMILY

PORTD is a bidirectional I/O port (continued).

RD6/AD6/PMD6/

SCK2/SCL2

RD6

AD6

PMD6(6)

SCK2

SCL2

I/O

TTL

Digital I/O.

External memory address/data 6.

Parallel Master Port data.

Synchronous serial clock input/output for SPI mode.

Synchronous serial clock input/output for I2C™ mode.

RD7/AD7/PMD7/SS2

RD7

AD7

PMD7(6)

SS2

I/O

TTL

Digital I/O.

External memory address/data 7.

Parallel Master Port data.

SPI slave select input.

TABLE 1-4: PIC18F8XJ5X PINOUT I/O DESCRIPTIONS (CONTINUED)

Pin Name

Pin Number Pin

Type

Buffer

Type Description

80-TQFP

Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output

ST = Schmitt Trigger input with CMOS levels Analog = Analog input

I = Input O = Output

P = Power OD = Open-Drain (no P diode to VDD)

Note 1: Alternate assignment for ECCP2/P2A when CCP2MX Configuration bit is cleared (Extended Microcontroller

mode).

2: Default assignment for ECCP2/P2A for all devices in all operating modes (CCP2MX is set).

3: Default assignments for P1B/P1C/P3B/P3C (ECCPMX Configuration bit is set).

4: Alternate assignment for ECCP2/P2A when CCP2MX is cleared (Microcontroller mode).

5: Alternate assignments for P1B/P1C/P3B/P3C (ECCPMX Configuration bit is cleared).

6: Pin placement when PMPMX = 1.

7: Pin placement when PMPMX = 0.

8: RA7 and RA6 will be disabled if OSC1 and OSC2 are used for the clock function.

PIC18F87J50 FAMILY

PORTE is a bidirectional I/O port.

RE0/AD8/PMRD/P2D

RE0

AD8

PMRD(6)

P2D

I/O

TTL

—

Digital I/O.

External memory address/data 8.

Parallel Master Port read strobe.

ECCP2 PWM output D.

RE1/AD9/PMWR/P2C

RE1

AD9

PMWR(6)

P2C

I/O

TTL

—

Digital I/O.

External memory address/data 9.

Parallel Master Port write strobe.

ECCP2 PWM output C.

RE2/AD10/PMBE/P2B

RE2

AD10

PMBE(6)

P2B

I/O

TTL

—

Digital I/O.

External memory address/data 10.

Parallel Master Port byte enable.

ECCP2 PWM output B.

RE3/AD11/PMA13/

P3C/REFO

RE3

AD11

PMA13

P3C(3)

REFO

I/O

TTL

—

Digital I/O.

External memory address/data 11.

Parallel Master Port address.

ECCP3 PWM output C.

Reference Clock out.

RE4/AD12/PMA12/P3B

RE4

AD12

PMA12

P3B(3)

I/O

TTL

—

Digital I/O.

External memory address/data 12.

Parallel Master Port address.

ECCP3 PWM output B.

RE5/AD13/PMA11/P1C

RE5

AD13

PMA11

P1C(3)

I/O

TTL

—

Digital I/O.

External memory address/data 13.

Parallel Master Port address.

ECCP1 PWM output C.

TABLE 1-4: PIC18F8XJ5X PINOUT I/O DESCRIPTIONS (CONTINUED)

Pin Name

Pin Number Pin

Type

Buffer

Type Description

80-TQFP

Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output

ST = Schmitt Trigger input with CMOS levels Analog = Analog input

I = Input O = Output

P = Power OD = Open-Drain (no P diode to VDD)

Note 1: Alternate assignment for ECCP2/P2A when CCP2MX Configuration bit is cleared (Extended Microcontroller

mode).

2: Default assignment for ECCP2/P2A for all devices in all operating modes (CCP2MX is set).

3: Default assignments for P1B/P1C/P3B/P3C (ECCPMX Configuration bit is set).

4: Alternate assignment for ECCP2/P2A when CCP2MX is cleared (Microcontroller mode).

5: Alternate assignments for P1B/P1C/P3B/P3C (ECCPMX Configuration bit is cleared).

6: Pin placement when PMPMX = 1.

7: Pin placement when PMPMX = 0.

8: RA7 and RA6 will be disabled if OSC1 and OSC2 are used for the clock function.

PIC18F87J50 FAMILY

PORTE is a bidirectional I/O port (continued).

RE6/AD14/PMA10/P1B

RE6

AD14

PMA10

P1B(3)

I/O

TTL

—

Digital I/O.

External memory address/data 14.

Parallel Master Port address.

ECCP1 PWM output B.

RE7/AD15/PMA9/

ECCP2/P2A

RE7

AD15

PMA9

ECCP2(4)

P2A(4)

I/O

TTL

—

Digital I/O.

External memory address/data 15.

Parallel Master Port address.

Capture 2 input/Compare 2 output/PWM2 output.

ECCP2 PWM output A.

TABLE 1-4: PIC18F8XJ5X PINOUT I/O DESCRIPTIONS (CONTINUED)

Pin Name

Pin Number Pin

Type

Buffer

Type Description

80-TQFP

Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output

ST = Schmitt Trigger input with CMOS levels Analog = Analog input

I = Input O = Output

P = Power OD = Open-Drain (no P diode to VDD)

Note 1: Alternate assignment for ECCP2/P2A when CCP2MX Configuration bit is cleared (Extended Microcontroller

mode).

2: Default assignment for ECCP2/P2A for all devices in all operating modes (CCP2MX is set).

3: Default assignments for P1B/P1C/P3B/P3C (ECCPMX Configuration bit is set).

4: Alternate assignment for ECCP2/P2A when CCP2MX is cleared (Microcontroller mode).

5: Alternate assignments for P1B/P1C/P3B/P3C (ECCPMX Configuration bit is cleared).

6: Pin placement when PMPMX = 1.

7: Pin placement when PMPMX = 0.

8: RA7 and RA6 will be disabled if OSC1 and OSC2 are used for the clock function.

PIC18F87J50 FAMILY

PORTF is a bidirectional I/O port.

RF2/PMA5/AN7/C2INB

RF2

PMA5

AN7

C2INB

I/O

—

Analog

Digital I/O.

Parallel Master Port address.

Analog input 7.

Comparator 2 input B.

RF3/D-

RF3

D-

I/O

—

Digital I/O.

Analog input 8.

RF4/D+

RF4

D+

I/O

—

Digital I/O.

Analog input 9.

RF5/PMD2/AN10/

C1INB/CVREF

RF5

PMD2(7)

AN10

C1INB

CVREF

I/O

TTL

Analog

Digital I/O.

Parallel Master Port address.

Analog input 10.

Comparator 1 input B.

Comparator reference voltage output.

RF6/PMD1/AN11/C1INA

RF6

PMD1(7)

AN11

C1INA

I/O

TTL

Analog

Digital I/O.

Parallel Master Port address.

Analog input 11.

Comparator 1 input A.

RF7/PMD0/SS1/C1OUT

RF7

PMD0(7)

SS1

C1OUT

I/O

TTL

—

Digital I/O.

Parallel Master Port address.

SPI slave select input.

Comparator 1 output.

TABLE 1-4: PIC18F8XJ5X PINOUT I/O DESCRIPTIONS (CONTINUED)

Pin Name

Pin Number Pin

Type

Buffer

Type Description

80-TQFP

Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output

ST = Schmitt Trigger input with CMOS levels Analog = Analog input

I = Input O = Output

P = Power OD = Open-Drain (no P diode to VDD)

Note 1: Alternate assignment for ECCP2/P2A when CCP2MX Configuration bit is cleared (Extended Microcontroller

mode).

2: Default assignment for ECCP2/P2A for all devices in all operating modes (CCP2MX is set).

3: Default assignments for P1B/P1C/P3B/P3C (ECCPMX Configuration bit is set).

4: Alternate assignment for ECCP2/P2A when CCP2MX is cleared (Microcontroller mode).

5: Alternate assignments for P1B/P1C/P3B/P3C (ECCPMX Configuration bit is cleared).

6: Pin placement when PMPMX = 1.

7: Pin placement when PMPMX = 0.

8: RA7 and RA6 will be disabled if OSC1 and OSC2 are used for the clock function.

PIC18F87J50 FAMILY

PORTG is a bidirectional I/O port.

RG0/PMA8/ECCP3/P3A

RG0

PMA8

ECCP3

P3A

I/O

—

Digital I/O.

Parallel Master Port address.

Capture 3 input/Compare 3 output/PWM3 output.

ECCP3 PWM output A.

RG1/PMA7/TX2/CK2

RG1

PMA7

TX2

CK2

I/O

—

Digital I/O.

Parallel Master Port address.

EUSART2 asynchronous transmit.

EUSART2 synchronous clock (see related RX2/DT2).

RG2/PMA6/RX2/DT2

RG2

PMA6

RX2

DT2

I/O

—

Digital I/O.

Parallel Master Port address.

EUSART2 asynchronous receive.

EUSART2 synchronous data (see related TX2/CK2).

RG3/PMCS1/CCP4/P3D

RG3

PMCS1

CCP4

P3D

I/O

—

Digital I/O.

Parallel Master Port chip select 1.

Capture 4 input/Compare 4 output/PWM4 output.

ECCP3 PWM output D.

RG4/PMCS2/CCP5/P1D

RG4

PMCS2

CCP5

P1D

I/O

—

Digital I/O.

Parallel Master Port chip select 2.

Capture 5 input/Compare 5 output/PWM5 output.

ECCP1 PWM output D.

TABLE 1-4: PIC18F8XJ5X PINOUT I/O DESCRIPTIONS (CONTINUED)

Pin Name

Pin Number Pin

Type

Buffer

Type Description

80-TQFP

Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output

ST = Schmitt Trigger input with CMOS levels Analog = Analog input

I = Input O = Output

P = Power OD = Open-Drain (no P diode to VDD)

Note 1: Alternate assignment for ECCP2/P2A when CCP2MX Configuration bit is cleared (Extended Microcontroller

mode).

2: Default assignment for ECCP2/P2A for all devices in all operating modes (CCP2MX is set).

3: Default assignments for P1B/P1C/P3B/P3C (ECCPMX Configuration bit is set).

4: Alternate assignment for ECCP2/P2A when CCP2MX is cleared (Microcontroller mode).

5: Alternate assignments for P1B/P1C/P3B/P3C (ECCPMX Configuration bit is cleared).

6: Pin placement when PMPMX = 1.

7: Pin placement when PMPMX = 0.

8: RA7 and RA6 will be disabled if OSC1 and OSC2 are used for the clock function.

PIC18F87J50 FAMILY

PORTH is a bidirectional I/O port.

RH0/A16

RH0

A16

I/O

TTL

Digital I/O.

External memory address/data 16.

RH1/A17

RH1

A17

I/O

TTL

Digital I/O.

External memory address/data 17.

RH2/A18/PMD7

RH2

A18

PMD7(7)

I/O

TTL

Digital I/O.

External memory address/data 18.

Parallel Master Port data.

RH3/A19/PMD6

RH3

A19

PMD6(7)

I/O

TTL

Digital I/O.

External memory address/data 19.

Parallel Master Port data.

RH4/PMD3/AN12/

P3C/C2INC

RH4

PMD3(7)

AN12

P3C(5)

C2INC

I/O

TTL

Analog

—

Analog

Digital I/O.

Parallel Master Port address.

Analog input 12.

ECCP3 PWM output C.

Comparator 2 input C.

RH5/PMBE/AN13/

P3B/C2IND

RH5

PMBE(7)

AN13

P3B(5)

C2IND

I/O

—

Analog

—

Analog

Digital I/O.

Parallel Master Port byte enable.

Analog input 13.

ECCP3 PWM output B.

Comparator 2 input D.

RH6/PMRD/AN14/

P1C/C1INC

RH6

PMRD(7)

AN14

P1C(5)

C1INC

I/O

—

Analog

—

Analog

Digital I/O.

Parallel Master Port read strobe.

Analog input 14.

ECCP1 PWM output C.

Comparator 1 input C.

TABLE 1-4: PIC18F8XJ5X PINOUT I/O DESCRIPTIONS (CONTINUED)

Pin Name

Pin Number Pin

Type

Buffer

Type Description

80-TQFP

Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output

ST = Schmitt Trigger input with CMOS levels Analog = Analog input

I = Input O = Output

P = Power OD = Open-Drain (no P diode to VDD)

Note 1: Alternate assignment for ECCP2/P2A when CCP2MX Configuration bit is cleared (Extended Microcontroller

mode).

2: Default assignment for ECCP2/P2A for all devices in all operating modes (CCP2MX is set).

3: Default assignments for P1B/P1C/P3B/P3C (ECCPMX Configuration bit is set).

4: Alternate assignment for ECCP2/P2A when CCP2MX is cleared (Microcontroller mode).

5: Alternate assignments for P1B/P1C/P3B/P3C (ECCPMX Configuration bit is cleared).

6: Pin placement when PMPMX = 1.

7: Pin placement when PMPMX = 0.

8: RA7 and RA6 will be disabled if OSC1 and OSC2 are used for the clock function.

PIC18F87J50 FAMILY

PORTH is a bidirectional I/O port (continued).

RH7/PMWR/AN15/P1B

RH7

PMWR(7)

AN15

P1B(5)

I/O

—

Analog

—

Digital I/O.

Parallel Master Port write strobe.

Analog input 15.

ECCP1 PWM output B.

TABLE 1-4: PIC18F8XJ5X PINOUT I/O DESCRIPTIONS (CONTINUED)

Pin Name

Pin Number Pin

Type

Buffer

Type Description

80-TQFP

Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output

ST = Schmitt Trigger input with CMOS levels Analog = Analog input

I = Input O = Output

P = Power OD = Open-Drain (no P diode to VDD)

Note 1: Alternate assignment for ECCP2/P2A when CCP2MX Configuration bit is cleared (Extended Microcontroller

mode).

2: Default assignment for ECCP2/P2A for all devices in all operating modes (CCP2MX is set).

3: Default assignments for P1B/P1C/P3B/P3C (ECCPMX Configuration bit is set).

4: Alternate assignment for ECCP2/P2A when CCP2MX is cleared (Microcontroller mode).

5: Alternate assignments for P1B/P1C/P3B/P3C (ECCPMX Configuration bit is cleared).

6: Pin placement when PMPMX = 1.

7: Pin placement when PMPMX = 0.

8: RA7 and RA6 will be disabled if OSC1 and OSC2 are used for the clock function.

PIC18F87J50 FAMILY

PORTJ is a bidirectional I/O port.

RJ0/ALE

RJ0

ALE

I/O

—

Digital I/O.

External memory address latch enable.

RJ1/OE

RJ1

I/O

—

Digital I/O.

External memory output enable.

RJ2/WRL

RJ2

WRL

I/O

—

Digital I/O.

External memory write low control.

RJ3/WRH

RJ3

WRH

I/O

—

Digital I/O.

External memory write high control.

RJ4/BA0

RJ4

BA0

I/O

—

Digital I/O.

External memory byte address 0 control.

RJ5/CE

RJ5

I/O

—

Digital I/O

External memory chip enable control.

RJ6/LB

RJ6

I/O

—

Digital I/O.

External memory low byte control.

RJ7/UB

RJ7

I/O

—

Digital I/O.

External memory high byte control.

VSS 11, 31, 51, 70 P — Ground reference for logic and I/O pins.

VDD 32, 48, 71 P — Positive supply for peripheral digital logic and I/O pins.

AVSS 26 P — Ground reference for analog modules.

AVDD 25 P — Positive supply for analog modules.

ENVREG 24 I ST Enable for on-chip voltage regulator.

VDDCORE/VCAP

VDDCORE

VCAP

—

Core logic power or external filter capacitor connection.

Positive supply for microcontroller core logic

(regulator disabled).

External filter capacitor connection (regulator enabled).

VUSB 23 P — USB voltage input pin.

TABLE 1-4: PIC18F8XJ5X PINOUT I/O DESCRIPTIONS (CONTINUED)

Pin Name

Pin Number Pin

Type

Buffer

Type Description

80-TQFP

Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output

ST = Schmitt Trigger input with CMOS levels Analog = Analog input

I = Input O = Output

P = Power OD = Open-Drain (no P diode to VDD)

Note 1: Alternate assignment for ECCP2/P2A when CCP2MX Configuration bit is cleared (Extended Microcontroller

mode).

2: Default assignment for ECCP2/P2A for all devices in all operating modes (CCP2MX is set).

3: Default assignments for P1B/P1C/P3B/P3C (ECCPMX Configuration bit is set).

4: Alternate assignment for ECCP2/P2A when CCP2MX is cleared (Microcontroller mode).

5: Alternate assignments for P1B/P1C/P3B/P3C (ECCPMX Configuration bit is cleared).

6: Pin placement when PMPMX = 1.

7: Pin placement when PMPMX = 0.

8: RA7 and RA6 will be disabled if OSC1 and OSC2 are used for the clock function.

PIC18F87J50 FAMILY

2.0 OSCILLATOR

CONFIGURATIONS

2.1 Overview

Devices in the PIC18F87J10 family incorporate a

different oscillator and microcontroller clock system

than general purpose PIC18F devices. The addition of

the USB module, with its unique requirements for a

stable clock source, make it necessary to provide a

separate clock source that is compliant with both USB

low-speed and full-speed specifications.

The PIC18F87J50 family has additional prescalers and

postscalers which have been added to accommodate a

wide range of oscillator frequencies. An overview of the

oscillator structure is shown in Figure 2-1.

Other oscillator features used in PIC18 enhanced

microcontrollers, such as the internal oscillator block

and clock switching, remain the same. They are

discussed later in this chapter.

2.1.1 OSCILLATOR CONTROL

The operation of the oscillator in PIC18F87J10 family

devices is controlled through three Configuration regis-

ters and two control registers. Configuration registers,

CONFIG1L, CONFIG1H and CONFIG2L, select the

oscillator mode, PLL prescaler and CPU divider options.

As Configuration bits, these are set when the device is

programmed and left in that configuration until the

device is reprogrammed.

The OSCCON register (Register 2-2) selects the Active

Clock mode; it is primarily used in controlling clock

switching in power-managed modes. Its use is

discussed in Section 2.4.1 “Oscillator Control

The OSCTUNE register (Register 2-1) is used to trim

the INTOSC frequency source, as well as select the

low-frequency clock source that drives several special

features. The OSCTUNE register is also used to

activate or disable the PLL. Its use is described in

Section 2.2.5.1 “OSCTUNE Register”.

2.2 Oscillator Types

PIC18F87J10 family devices can be operated in eight

distinct oscillator modes. Users can program the

FOSC2:FOSC0 Configuration bits to select one of the

modes listed in Table 2-1. For oscillator modes which

produce a clock output, “CLKO”, on pin RA6, the output

frequency will be one fourth of the peripheral clock

frequency. The clock output will stop when in Sleep

mode, but will continue during Idle mode (see

Figure 2-1).

TABLE 2-1: OSCILLATOR MODES

Mode Description

ECPLL External Clock Input mode, the PLL can

be enabled or disabled, CLKO on RA6,

apply external clock signal to RA7

EC External Clock Input mode, the PLL is

always disabled, CLKO on RA6, apply

external clock signal to RA7

HSPLL High-Speed Crystal/Resonator mode,

PLL can be enabled or disabled, crystal/

resonator connected between RA6 and

RA7

HS High-Speed Crystal/Resonator mode,

PLL always disabled, crystal/resonator

connected between RA6 and RA7

INTOSCPLLO Internal Oscillator mode, PLL can be

enabled or disabled, CLKO on RA6, port

function on RA7, the internal oscillator

block is used to derive both the primary

clock source and the postscaled internal

clock

INTOSCPLL Internal Oscillator mode, PLL can be

enabled or disabled, port function on

RA6 and RA7, the internal oscillator

block is used to derive both the primary

clock source and the postscaled internal

clock

INTOSCO Internal Oscillator mode, PLL is always

disabled, CLKO on RA6, port function on

RA7, the output of the INTOSC

postscaler serves as both the postscaled

internal clock and the primary clock

source

INTOSC Internal Oscillator mode, PLL is always

disabled, port function on RA6 and RA7,

the output of the INTOSC postscaler

serves as both the postscaled internal

clock and the primary clock source

PIC18F87J50 FAMILY

2.2.1 OSCILLATOR MODES AND

USB OPERATION

Because of the unique requirements of the USB module,

a different approach to clock operation is necessary. In

order to use the USB module, a fixed 6 MHz or 48 MHz

clock must be internally provided to the USB module for

operation in either Low-Speed or Full-Speed mode,

respectively. The microcontroller core need not be

clocked at the same frequency as the USB module.

A network of MUXes, clock dividers and a fixed 96 MHz

output PLL have been provided which can be used to

derive various microcontroller core and USB module

frequencies. The oscillator structure of the

PIC18F87J50 family of devices is best understood by

referring to Figure 2-1.

FIGURE 2-1: PIC18F87J50 FAMILY CLOCK DIAGRAM

OSC1

OSC2

Primary Oscillator

CPU

Peripherals

IDLE

INTOSC Postscaler

8 MHz

4 MHz

2 MHz

1 MHz

500 kHz

125 kHz

250 kHz

111

110

101

100

011

010

001

000

31 kHz

INTRC

31 kHz

Internal

Oscillator

Block

8 MHz

OSCTUNE<7>

PLLDIV2:PLLDIV0

CPU Divider

÷ 1

÷ 2

÷ 3

÷ 6

USB Module

4 MHz

WDT, PWRT, FSCM

and Two-Speed Start-up

OSCCON<6:4>

PLLEN

FOSC2

PLL Prescaler

96 MHz

PLL(1) ÷ 2

FSEN

÷ 8 10

÷ 4

CPDIV1:CPDIV0

(Note 2)

FOSC2:FOSC1

Other

OSCCON<1:0>

÷ 4

RA6

CLKO

Enabled Modes

Timer1 Clock(3)

Postscaled

Internal Clock

T1OSI

T1OSO

Secondary Oscillator

T1OSCEN

Clock

Needs 48 MHz for FS

Needs 6 MHz for LS

Note 1: The PLL requires a 4 MHz input and it produces a 96 MHz output. The PLL will not be available until the PLLEN bit

in the OSCTUNE register is set. Once the PLLEN bit is set, the PLL requires up to 2 ms to lock.

2: In order to use the USB module in Full-Speed mode, this node must be run at 48 MHz. For Low-Speed mode, this

node may be run at either 48 MHz or 24 MHz, but the CPDIV bits must be set such that the USB module is clocked

at 6 MHz.

3: Selecting the Timer1 clock or postscaled internal clock will turn off the primary oscillator (unless required by the

reference clock of Section 2.5 “Reference Clock Output”) and PLL.

4: The USB module cannot be used to communicate unless the primary clock source is selected.

÷ 12

÷ 10

÷ 6

÷ 5

÷ 4

÷ 3

÷ 2

÷ 1

000

001

010

011

100

101

110

111

48 MHz

Primary Clock

Source(4)

PIC18F87J50 FAMILY

2.2.2 CRYSTAL OSCILLATOR/CERAMIC

RESONATORS

In HS and HSPLL Oscillator modes, a crystal or

ceramic resonator is connected to the OSC1 and

OSC2 pins to establish oscillation. Figure 2-2 shows

the pin connections.

The oscillator design requires the use of a parallel cut

crystal.

FIGURE 2-2: CRYSTAL/CERAMIC

RESONATOR OPERATION

(XT, HS OR HSPLL

CONFIGURATION)

TABLE 2-2: CAPACITOR SELECTION FOR

CERAMIC RESONATORS

TABLE 2-3: CAPACITOR SELECTION FOR

CRYSTAL OSCILLATOR

An internal postscaler allows users to select a clock

frequency other than that of the crystal or resonator.

Frequency division is determined by the CPDIV

Configuration bits. Users may select a clock frequency

of the oscillator frequency, or 1/2, 1/3 or 1/6 of the

frequency.

An external clock may also be used when the micro-

controller is in HS Oscillator mode. In this case, the

OSC2/CLKO pin is left open (Figure 2-3).

Note: Use of a series cut crystal may give a fre-

quency out of the crystal manufacturer’s

specifications.

Typical Capacitor Values Used:

Mode Freq OSC1 OSC2

HS 8.0 MHz

16.0 MHz

27 pF

22 pF

27 pF

22 pF

Capacitor values are for design guidance only.

These capacitors were tested with the resonators

listed below for basic start-up and operation. These

values are not optimized.

Different capacitor values may be required to produce

acceptable oscillator operation. The user should test

the performance of the oscillator over the expected

VDD and temperature range for the application.

See the notes following Table 2-3 for additional

information.

Resonators Used:

4.0 MHz

8.0 MHz

16.0 MHz

Note 1: See Table 2-2 and Table 2-3 for initial values of

C1 and C2.

2: A series resistor (RS) may be required for AT

strip cut crystals.

3: RF varies with the oscillator mode chosen.

C1(1)

C2(1)

XTAL

OSC2

OSC1

RF(3)

Sleep

Logic

PIC18F87J50

RS(2)

Internal

Osc Type Crystal

Freq

Typical Capacitor Values

Tested:

C1 C2

HS 4 MHz 27 pF 27 pF

8 MHz 22 pF 22 pF

20 MHz 15 pF 15 pF

Capacitor values are for design guidance only.

These capacitors were tested with the crystals listed

below for basic start-up and operation. These values

are not optimized.

Different capacitor values may be required to produce

acceptable oscillator operation. The user should test

the performance of the oscillator over the expected

VDD and temperature range for the application.

See the notes following this table for additional

information.

Crystals Used:

4 MHz

8 MHz

20 MHz

Note 1: Higher capacitance increases the stability

of oscillator but also increases the

start-up time.

2: When operating below 3V VDD, or when

using certain ceramic resonators at any

voltage, it may be necessary to use the

HS mode or switch to a crystal oscillator.

3: Since each resonator/crystal has its own

characteristics, the user should consult

the resonator/crystal manufacturer for

appropriate values of external

components.

4: Rs may be required to avoid overdriving

crystals with low drive level specification.

5: Always verify oscillator performance over

the VDD and temperature range that is

expected for the application.

PIC18F87J50 FAMILY

FIGURE 2-3: EXTERNAL CLOCK INPUT

OPERATION (HS OSC

CONFIGURATION)

2.2.3 EXTERNAL CLOCK INPUT

The EC and ECPLL Oscillator modes require an exter-

nal clock source to be connected to the OSC1 pin.

There is no oscillator start-up time required after a

Power-on Reset or after an exit from Sleep mode.

In the EC and ECPLL Oscillator modes, the oscillator

frequency divided by 4 is available on the OSC2 pin.

This signal may be used for test purposes or to

synchronize other logic. Figure 2-4 shows the pin

connections for the EC Oscillator mode.

FIGURE 2-4: EXTERNAL CLOCK INPUT

OPERATION (EC AND

ECPLL CONFIGURATION)

2.2.4 PLL FREQUENCY MULTIPLIER

PIC18F87J10 family devices include a Phase Locked

Loop (PLL) circuit. This is provided specifically for USB

applications with lower speed oscillators and can also

be used as a microcontroller clock source.

The PLL can be enabled in HSPLL, ECPLL,

INTOSCPLL and INTOSCPLLO Oscillator modes by

setting the PLLEN bit (OSCTUNE<6>). It is designed

to produce a fixed 96 MHz reference clock from a

fixed 4 MHz input. The output can then be divided and

used for both the USB and the microcontroller core

clock. Because the PLL has a fixed frequency input

and output, there are eight prescaling options to

match the oscillator input frequency to the PLL. This

prescaler allows the PLL to be used with crystals, res-

onators and external clocks, which are integer multiple

frequencies of 4 MHz. For example, a 12 MHz crystal

could be used in a prescaler divide by three mode to

drive the PLL.

There is also a CPU divider which can be used to derive

the microcontroller clock from the PLL. This allows the

USB peripheral and microcontroller to use the same

oscillator input and still operate at different clock speeds.

The CPU divider can reduce the incoming frequency by

a factor of 1, 2, 3 or 6.

2.2.5 INTERNAL OSCILLATOR BLOCK

The PIC18F87J10 family devices include an internal

oscillator block which generates two different clock sig-

nals; either can be used as the microcontroller’s clock

source. The internal oscillator may eliminate the need

for external oscillator circuits on the OSC1 and/or

OSC2 pins.

The main output (INTOSC) is an 8 MHz clock source

which can be used to directly drive the device clock. It

also drives the INTOSC postscaler which can provide a

range of clock frequencies from 31 kHz to 8 MHz.

Additionally, the INTOSC may be used in conjunction

with the PLL to generate clock frequencies up to

48 MHz.

The other clock source is the internal RC oscillator

(INTRC) which provides a nominal 31 kHz output.

INTRC is enabled if it is selected as the device clock

source. It is also enabled automatically when any of the

following are enabled:

• Power-up Timer

• Fail-Safe Clock Monitor

• Watchdog Timer

• Two-Speed Start-up

These features are discussed in greater detail in

Section 25.0 “Special Features of the CPU”.

The clock source frequency (INTOSC direct, INTRC

direct or INTOSC postscaler) is selected by configuring

the IRCF bits of the OSCCON register (page 44).

OSC1

OSC2

Open

Clock from

Ext. System PIC18F87J50

(HS Mode)

OSC1/CLKI

OSC2/CLKO

FOSC/4

Clock from

Ext. System PIC18F87J50

PIC18F87J50 FAMILY

2.2.5.1 OSCTUNE Register

The internal oscillator’s output has been calibrated at

the factory but can be adjusted in the user’s applica-

tion. This is done by writing to the OSCTUNE register

(Register 2-1). The tuning sensitivity is constant

throughout the tuning range.

When the OSCTUNE register is modified, the INTOSC

and INTRC frequencies will begin shifting to the new

frequency. The INTRC clock will reach the new

frequency within 8 clock cycles (approximately,

8*32μs = 256 μs). The INTOSC clock will stabilize

within 1 ms. Code execution continues during this shift.

There is no indication that the shift has occurred.

The OSCTUNE register also contains the INTSRC bit.

The INTSRC bit allows users to select which internal

oscillator provides the clock source when the 31 kHz

frequency option is selected. This is covered in greater

detail in Section 2.4.1 “Oscillator Control Register”.

The PLLEN bit, contained in the OSCTUNE register,

can be used to enable or disable the internal 96 MHz

PLL when running in one of the PLL type oscillator

modes (e.g., INTOSCPLL). Oscillator modes that do

not contain “PLL” in their name cannot be used with

the PLL. In these modes, the PLL is always disabled

regardless of the setting of the PLLEN bit.

When configured for one of the PLL enabled modes,

setting the PLLEN bit does not immediately switch the

device clock to the PLL output. The PLL requires up to

two milliseconds to start up and lock during which time

the device continues to be clocked. Once the PLL out-

put is ready, the microcontroller core will automatically

switch to the PLL derived frequency.

2.2.5.2 Internal Oscillator Output Frequency

and Drift

The internal oscillator block is calibrated at the factory

to produce an INTOSC output frequency of 8.0 MHz.

However, this frequency may drift as VDD or tempera-

ture changes, which can affect the controller operation

in a variety of ways.

The low-frequency INTRC oscillator operates indepen-

dently of the INTOSC source. Any changes in INTOSC

across voltage and temperature are not necessarily

reflected by changes in INTRC and vice versa.

2.2.5.3 Compensating for INTOSC Drift

It is possible to adjust the INTOSC frequency by

modifying the value in the OSCTUNE register. This has

no effect on the INTRC clock source frequency.

Tuning the INTOSC source requires knowing when to

make the adjustment, in which direction it should be

made and in some cases, how large a change is

needed. When using the EUSART, for example, an

adjustment may be required when it begins to generate

framing errors or receives data with errors while in

Asynchronous mode. Framing errors indicate that the

device clock frequency is too high; to adjust for this,

decrement the value in OSCTUNE to reduce the clock

frequency. On the other hand, errors in data may sug-

gest that the clock speed is too low; to compensate,

increment OSCTUNE to increase the clock frequency.

It is also possible to verify device clock speed against

a reference clock. Two timers may be used: one timer

is clocked by the peripheral clock, while the other is

clocked by a fixed reference source, such as the

Timer1 oscillator. Both timers are cleared but the timer

clocked by the reference generates interrupts. When

an interrupt occurs, the internally clocked timer is read

and both timers are cleared. If the internally clocked

timer value is greater than expected, then the internal

oscillator block is running too fast. To adjust for this,

decrement the OSCTUNE register.

Finally, a CCP module can use free-running Timer1 (or

Timer3), clocked by the internal oscillator block and an

external event with a known period (i.e., AC power

frequency). The time of the first event is captured in the

CCPRxH:CCPRxL registers and is recorded for use

later. When the second event causes a capture, the

time of the first event is subtracted from the time of the

second event. Since the period of the external event is

known, the time difference between events can be

calculated.

If the measured time is much greater than the calcu-

lated time, the internal oscillator block is running too

fast; to compensate, decrement the OSCTUNE register.

If the measured time is much less than the calculated

time, the internal oscillator block is running too slow; to

compensate, increment the OSCTUNE register.

PIC18F87J50 FAMILY

2.3 Oscillator Settings for USB

When the PIC18F87J10 family is used for USB

connectivity, a 6 MHz or 48 MHz clock must be

provided to the USB module for operation in either

Low-Speed or Full-Speed modes, respectively. This

may require some forethought in selecting an oscillator

frequency and programming the device.

The full range of possible oscillator configurations

compatible with USB operation is shown in Table 2-5.

2.3.1 LOW-SPEED OPERATION

The USB clock for Low-Speed mode is derived from the

primary oscillator or from the 96 MHz PLL. In order to

operate the USB module in Low-Speed mode, a 6 MHz

clock must be provided to the USB module. Due to the

way the clock dividers have been implemented in the

PIC18F87J50 family, the microcontroller core must run

at 24 MHz in order for the USB module to get the 6 MHz

clock needed for low-speed USB operation. Several

clocking schemes could be used to meet these two

required conditions. See Table 2-4 and Table 2-5 for

possible combinations which can be used for

low-speed USB operation.

TABLE 2-4: CLOCK FOR LOW-SPEED

USB

R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

INTSRC PLLEN TUN5 TUN4 TUN3 TUN2 TUN1 TUN0

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 INTSRC: Internal Oscillator Low-Frequency Source Select bit

1 = 31.25 kHz device clock derived from 8 MHz INTOSC source (divide-by-256 enabled)

0 = 31 kHz device clock derived directly from INTRC internal oscillator

bit 6 PLLEN: Frequency Multiplier Enable bit

1 = 96 MHz PLL is enabled

0 = 96 MHz PLL is disabled

bit 5-0 TUN5:TUN0: Frequency Tuning bits

011111 = Maximum frequency

011110

• •

000001

000000 = Center frequency. Oscillator module is running at the calibrated frequency.

111111

• •

100000 = Minimum frequency

Clock

Input

CPU

Clock CPDIV<1:0> USB Clock

48 24 <1, 1> 48/8 = 6 MHz

24 24 <1, 0> 24/4 = 6 MHz

PIC18F87J50 FAMILY

TABLE 2-5: OSCILLATOR CONFIGURATION OPTIONS FOR USB OPERATION

Input Oscillator

Frequency

PLL Division

(PLLDIV2:PLLDIV0)

Clock Mode

(FOSC2:FOSC0)

MCU Clock Division

(CPDIV1:CPDIV0)

Microcontroller

Clock Frequency

48 MHz N/A EC

None (11)48MHz

÷2 (10)24 MHz

÷3 (01)16MHz

÷6 (00)8MHz

48 MHz ÷12 (000)ECPLL

None (11)48MHz

÷2 (10)24 MHz

÷3 (01)16MHz

÷6 (00)8MHz

40 MHz ÷10 (001)ECPLL

None (11)48MHz

÷2 (10)24 MHz

÷3 (01)16MHz

÷6 (00)8MHz

24 MHz ÷6 (010) HSPLL, ECPLL

None (11)48MHz

÷2 (10)24 MHz

÷3 (01)16MHz

÷6 (00)8MHz

24 MHz N/A(1) EC, HS

None (11)24 MHz

÷2 (10)12MHz

÷3 (01)8MHz

÷6 (00)4MHz

20 MHz ÷5 (011) HSPLL, ECPLL

None (11)48MHz

÷2 (10)24 MHz

÷3 (01)16MHz

÷6 (00)8MHz

16 MHz ÷4 (100) HSPLL, ECPLL

None (11)48MHz

÷2 (10)24 MHz

÷3 (01)16MHz

÷6 (00)8MHz

12 MHz ÷3 (101) HSPLL, ECPLL

None (11)48MHz

÷2 (10)24 MHz

÷3 (01)16MHz

÷6 (00)8MHz

8MHz ÷2 (110) HSPLL, ECPLL

None (11)48MHz

÷2 (10)24 MHz

÷3 (01)16MHz

÷6 (00)8MHz

4MHz ÷1 (111) HSPLL, ECPLL

None (11)48MHz

÷2 (10)24 MHz

÷3 (01)16MHz

÷6 (00)8MHz

Legend: All clock frequencies, except 24 MHz, are exclusively associated with full-speed USB operation (USB clock of 48 MHz).

Bold is used to highlight clock selections that are compatible with low-speed USB operation (system clock of 24 MHz,

USB clock of 6 MHz).

Note 1: Only valid for low-speed USB operation.

PIC18F87J50 FAMILY

2.4 Clock Sources and Oscillator

Switching

Like previous PIC18 enhanced devices, the

PIC18F87J10 family includes a feature that allows the

device clock source to be switched from the main

oscillator to an alternate, low-frequency clock source.

PIC18F87J10 family devices offer two alternate clock

sources. When an alternate clock source is enabled,

the various power-managed operating modes are

available.

Essentially, there are three clock sources for these

devices:

• Primary oscillators

• Secondary oscillators

• Internal oscillator block

The primary clock sources include the External

Crystal and Resonator modes, the External Clock

modes and the internal oscillator block. The particular

mode is defined by the FOSC2:FOSC0 Configuration

bits. The details of these modes are covered earlier in

this chapter.

The secondary oscillators are those external sources

not connected to the OSC1 or OSC2 pins. These

sources may continue to operate even after the

controller is placed in a power-managed mode.

PIC18F87J10 family devices offer the Timer1 oscillator

as a secondary oscillator. This oscillator, in all

power-managed modes, is often the time base for

functions such as a Real-Time Clock (RTC). Most

often, a 32.768 kHz watch crystal is connected

between the RC0/T1OSO/T13CKI and RC1/T1OSI/

ECCP2/P2A pins. Like the HS Oscillator mode circuits,

loading capacitors are also connected from each pin to

ground. The Timer1 oscillator is discussed in greater

detail in Section 13.3 “Timer1 Oscillator”.

In addition to being a primary clock source, the

postscaled internal clock is available as a

power-managed mode clock source. The INTRC

source is also used as the clock source for several

special features, such as the WDT and Fail-Safe Clock

Monitor.

2.4.1 OSCILLATOR CONTROL REGISTER

The OSCCON register (Register 2-2) controls several

aspects of the device clock’s operation, both in

full-power operation and in power-managed modes.

The System Clock Select bits, SCS1:SCS0, select the

clock source. The available clock sources are the

primary clock (defined by the FOSC2:FOSC0 Configu-

ration bits), the secondary clock (Timer1 oscillator) and

the postscaled internal clock.The clock source changes

immediately, after one or more of the bits is written to,

following a brief clock transition interval. The SCS bits

are cleared on all forms of Reset.

The Internal Oscillator Frequency Select bits,

IRCF2:IRCF0, select the frequency output provided on

the postscaled internal clock line. The choices are the

INTRC source, the INTOSC source (8 MHz) or one of

the frequencies derived from the INTOSC postscaler

(31 kHz to 4 MHz). If the postscaled internal clock is

supplying the device clock, changing the states of these

bits will have an immediate change on the internal oscil-

lator’s output. On device Resets, the default output

frequency of the INTOSC postscaler is set at 4 MHz.

When an output frequency of 31 kHz is selected

(IRCF2:IRCF0 = 000), users may choose which inter-

nal oscillator acts as the source. This is done with the

INTSRC bit in the OSCTUNE register (OSCTUNE<7>).

Setting this bit selects INTOSC as a 31.25 kHz clock

source by enabling the divide-by-256 output of the

INTOSC postscaler. Clearing INTSRC selects INTRC

(nominally 31 kHz) as the clock source.

This option allows users to select the tunable and more

precise INTOSC as a clock source, while maintaining

power savings with a very low clock speed. Regardless

of the setting of INTSRC, INTRC always remains the

clock source for features such as the Watchdog Timer

and the Fail-Safe Clock Monitor.

The OSTS and T1RUN bits indicate which clock source

is currently providing the device clock. The OSTS bit

indicates that the Oscillator Start-up Timer (OST) has

timed out and the primary clock is providing the device

clock in primary clock modes. The T1RUN bit

(T1CON<6>) indicates when the Timer1 oscillator is

providing the device clock in secondary clock modes. In

power-managed modes, only one of these bits will be set

at any time. If none of these bits are set, the INTRC is

providing the clock or the internal oscillator block has just

started and is not yet stable.

The IDLEN bit determines if the device goes into Sleep

mode, or one of the Idle modes, when the SLEEP

instruction is executed.

PIC18F87J50 FAMILY

The use of the flag and control bits in the OSCCON

“Power-Managed Modes”.

2.4.2 OSCILLATOR TRANSITIONS

PIC18F87J10 family devices contain circuitry to

prevent clock “glitches” when switching between clock

sources. A short pause in the device clock occurs dur-

ing the clock switch. The length of this pause is the sum

of two cycles of the old clock source and three to four

cycles of the new clock source. This formula assumes

that the new clock source is stable.

Clock transitions are discussed in greater detail in

Section 3.1.2 “Entering Power-Managed Modes”.

Note 1: The Timer1 oscillator must be enabled to

select the Timer1 clock. The Timer1 oscil-

lator is enabled by setting the T1OSCEN

bit in the Timer1 Control register

(T1CON<3>). If the Timer1 oscillator is not

enabled, then any attempt to select the

Timer1 clock source will be ignored.

2: It is recommended that the Timer1

oscillator be operating and stable prior to

switching to it as the clock source; other-

wise, a very long delay may occur while

the Timer1 oscillator starts.

PIC18F87J50 FAMILY

R/W-0 R/W-1 R/W-1 R/W-0 R-1(2) U-1 R/W-0 R/W-0

IDLEN IRCF2 IRCF1 IRCF0 OSTS —SCS1SCS0

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 IDLEN: Idle Enable bit

1 = Device enters Idle mode on SLEEP instruction

0 = Device enters Sleep mode on SLEEP instruction

bit 6-4 IRCF2:IRCF0: Internal Oscillator Frequency Select bits

111 = 8 MHz (INTOSC drives clock directly)

110 = 4 MHz(3)

101 = 2 MHz

100 = 1 MHz

011 = 500 kHz

010 = 250 kHz

001 = 125 kHz

000 = 31 kHz (from either INTOSC/256 or INTRC directly)(4)

bit 3 OSTS: Oscillator Start-up Time-out Status bit(2)

1 = Oscillator Start-up Timer time-out has expired; primary oscillator is running

0 = Oscillator Start-up Timer time-out is running; primary oscillator is not ready

bit 2 Unimplemented: Read as ‘1’

bit 1-0 SCS1:SCS0: System Clock Select bits

11 = Postscaled internal clock (INTRC/INTOSC derived)

10 = Reserved

01 = Timer1 oscillator

00 = Primary clock source (INTOSC postscaler output when FOSC2:FOSC0 = 001 or 000)

00 = Primary clock source (CPU divider output for other values of FOSC2:FOSC0)

Note 1: Default (legacy) SFR at this address, available when WDTCON<4> = 0.

Reset value is ‘

’ when Two-Speed Start-up is enabled and ‘

’ if disabled.

3: Default output frequency of INTOSC on Reset (4 MHz).

4: Source selected by the INTSRC bit (OSCTUNE<7>), see text.

PIC18F87J50 FAMILY

2.5 Reference Clock Output

In addition to the peripheral clock/4 output in certain

oscillator modes, the device clock in the PIC18F87J10

family can also be configured to provide a reference

clock output signal to a port pin. This feature is avail-

able in all oscillator configurations and allows the user

to select a greater range of clock submultiples to drive

external devices in the application.

This reference clock output is controlled by the

REFOCON register (Register 2-3). Setting the ROON

bit (REFOCON<7>) makes the clock signal available

on the REFO (RE3) pin. The RODIV3:RODIV0 bits

enable the selection of 16 different clock divider

options.

The ROSSLP and ROSEL bits (REFOCON<5:4>) con-

trol the availability of the reference output during Sleep

mode. The ROSEL bit determines if the oscillator on

OSC1 and OSC2, or the current system clock source,

is used for the reference clock output. The ROSSLP bit

determines if the reference source is available on RE3

when the device is in Sleep mode.

To use the reference clock output in Sleep mode, both

the ROSSLP and ROSEL bits must be set. The device

clock must also be configured for an EC or HS mode;

otherwise, the oscillator on OSC1 and OSC2 will be

powered down when the device enters Sleep mode.

Clearing the ROSEL bit allows the reference output

frequency to change as the system clock changes

during any clock switches.

The REFOCON register is an alternate SFR and

shares the same memory address as the OSCCON

(WDTCON<4>) in the WDTCON register (see

R/W-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

ROON — ROSSLP ROSEL RODIV3 RODIV2 RODIV1 RODIV0

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 ROON: Reference Oscillator Output Enable bit

1 = Reference oscillator enabled on REFO pin

0 = Reference oscillator disabled

bit 6 Unimplemented: Read as ‘0’

bit 5 ROSSLP: Reference Oscillator Output Stop in Sleep bit

1 = Reference oscillator continues to run in Sleep

0 = Reference oscillator is disabled in Sleep

bit 4 ROSEL: Reference Oscillator Source Select bit

1 = Primary oscillator used as the base clock. Note that the crystal oscillator must be enabled using

the FOSC2:FOSC0 bits; crystal maintains the operation in Sleep mode.

0 = System clock used as the base clock; base clock reflects any clock switching of the device

bit 3-0 RODIV3:RODIV0: Reference Oscillator Divisor Select bits

1111 = Base clock value divided by 32,768

1110 = Base clock value divided by 16,384

1101 = Base clock value divided by 8,192

1100 = Base clock value divided by 4,096

1011 = Base clock value divided by 2,048

1010 = Base clock value divided by 1,024

1001 = Base clock value divided by 512

1000 = Base clock value divided by 256

0111 = Base clock value divided by 128

0110 = Base clock value divided by 64

0101 = Base clock value divided by 32

0100 = Base clock value divided by 16

0011 = Base clock value divided by 8

0010 = Base clock value divided by 4

0001 = Base clock value divided by 2

0000 = Base clock value

PIC18F87J50 FAMILY

2.6 Effects of Power-Managed Modes

on the Various Clock Sources

When PRI_IDLE mode is selected, the designated

primary oscillator continues to run without interruption.

For all other power-managed modes, the oscillator

using the OSC1 pin is disabled. Unless the USB

module is enabled, the OSC1 pin (and OSC2 pin if

used by the oscillator) will stop oscillating.

In secondary clock modes (SEC_RUN and

SEC_IDLE), the Timer1 oscillator is operating and

providing the device clock. The Timer1 oscillator may

also run in all power-managed modes if required to

clock Timer1 or Timer3.

In internal oscillator modes (RC_RUN and RC_IDLE),

the internal oscillator block provides the device clock

source. The 31 kHz INTRC output can be used directly

to provide the clock and may be enabled to support

various special features regardless of the

power-managed mode (see Section 25.2 “Watchdog

Timer (WDT)”, Section 25.4 “Two-Speed Start-up”

and Section 25.5 “Fail-Safe Clock Monitor” for more

information on WDT, Fail-Safe Clock Monitor and

Two-Speed Start-up). The INTOSC output at 8 MHz

may be used directly to clock the device or may be

divided down by the postscaler. The INTOSC output is

disabled if the clock is provided directly from the INTRC

output.

If the Sleep mode is selected, all clock sources which

are no longer required are stopped. Since all the tran-

sistor switching currents have been stopped, Sleep

mode achieves the lowest current consumption of the

device (only leakage currents).

Sleep mode should not be invoked while the USB mod-

ule is enabled and operating in full-power mode. Before

Sleep mode is selected, the USB module should be put

in the suspend state. This is accomplished by setting

the SUSPND bit in the UCON register.

Enabling any on-chip feature that will operate during

Sleep will increase the current consumed during Sleep.

The INTRC is required to support WDT operation. The

Timer1 oscillator may be operating to support a

Real-Time Clock. Other features may be operating that

do not require a device clock source (i.e., MSSP slave,

PMP, INTx pins and others). Peripherals that may add

significant current consumption are listed in

Section 28.2 “DC Characteristics: Power-Down and

Supply Current”.

2.7 Power-up Delays

Power-up delays are controlled by two timers so that no

external Reset circuitry is required for most applications.

The delays ensure that the device is kept in Reset until

the device power supply is stable under normal circum-

stances and the primary clock is operating and stable.

For additional information on power-up delays, see

Section 4.6 “Power-up Timer (PWRT)”.

The first timer is the Power-up Timer (PWRT), which

provides a fixed delay on power-up (parameter 33,

Table 28-13).

The second timer is the Oscillator Start-up Timer

(OST), intended to keep the chip in Reset until the

crystal oscillator is stable (HS mode). The OST does

this by counting 1024 oscillator cycles before allowing

the oscillator to clock the device.

There is a delay of interval, TCSD (parameter 38,

Table 28-13), following POR, while the controller

becomes ready to execute instructions. This delay runs

concurrently with any other delays. This may be the

only delay that occurs when any of the EC or internal

oscillator modes are used as the primary clock source.

PIC18F87J50 FAMILY

3.0 POWER-MANAGED MODES

The PIC18F87J10 family devices provide the ability to

manage power consumption by simply managing clock-

ing to the CPU and the peripherals. In general, a lower

clock frequency and a reduction in the number of circuits

being clocked constitutes lower consumed power. For

the sake of managing power in an application, there are

three primary modes of operation:

• Run mode

• Idle mode

• Sleep mode

These modes define which portions of the device are

clocked and at what speed. The Run and Idle modes

may use any of the three available clock sources

(primary, secondary or internal oscillator block); the

Sleep mode does not use a clock source.

The power-managed modes include several

power-saving features offered on previous PIC®

devices. One is the clock switching feature, offered in

other PIC18 devices, allowing the controller to use the

Timer1 oscillator in place of the primary oscillator. Also

included is the Sleep mode, offered by all PIC devices,

where all device clocks are stopped.

3.1 Selecting Power-Managed Modes

Selecting a power-managed mode requires two

decisions: if the CPU is to be clocked or not and which

clock source is to be used. The IDLEN bit

(OSCCON<7>) controls CPU clocking, while the

SCS1:SCS0 bits (OSCCON<1:0>) select the clock

source. The individual modes, bit settings, clock

sources and affected modules are summarized in

Table 3-1.

3.1.1 CLOCK SOURCES

The SCS1:SCS0 bits allow the selection of one of three

clock sources for power-managed modes. They are:

• The primary clock source, as defined by the

FOSC2:FOSC0 Configuration bits

• The Timer1 clock (provided by the secondary

oscillator)

• The postscaled internal clock (derived from the

internal oscillator block)

3.1.2 ENTERING POWER-MANAGED

MODES

Switching from one power-managed mode to another

begins by loading the OSCCON register. The

SCS1:SCS0 bits select the clock source and determine

which Run or Idle mode is to be used. Changing these

bits causes an immediate switch to the new clock

source, assuming that it is running. The switch may

also be subject to clock transition delays. These are

discussed in Section 3.1.3 “Clock Transitions and

Status Indicators” and subsequent sections.

Entry to the power-managed Idle or Sleep modes is

triggered by the execution of a SLEEP instruction. The

actual mode that results depends on the status of the

IDLEN bit.

Depending on the current mode and the mode being

switched to, a change to a power-managed mode does

not always require setting all of these bits. Many

transitions may be done by changing the oscillator

select bits, or changing the IDLEN bit, prior to issuing a

SLEEP instruction. If the IDLEN bit is already

configured correctly, it may only be necessary to

perform a SLEEP instruction to switch to the desired

mode.

TABLE 3-1: POWER-MANAGED MODES

Mode

OSCCON<7,1:0> Module Clocking

Available Clock and Oscillator Source

IDLEN(1) SCS1:SCS0 CPU Peripherals

Sleep 0N/A Off Off None – All clocks are disabled

PRI_RUN N/A 00 Clocked Clocked Primary clock source (defined by FOSC2:FOSC0);

this is the normal full-power execution mode

SEC_RUN N/A 01 Clocked Clocked Secondary – Timer1 oscillator

RC_RUN N/A 11 Clocked Clocked Postscaled internal clock

PRI_IDLE 100Off Clocked Primary clock source (defined by FOSC2:FOSC0)

SEC_IDLE 101Off Clocked Secondary – Timer1 oscillator

RC_IDLE 111Off Clocked Postscaled internal clock

Note 1: IDLEN reflects its value when the SLEEP instruction is executed.

PIC18F87J50 FAMILY

3.1.3 CLOCK TRANSITIONS AND STATUS

INDICATORS

The length of the transition between clock sources is

the sum of two cycles of the old clock source and three

to four cycles of the new clock source. This formula

assumes that the new clock source is stable.

Two bits indicate the current clock source and its

status: OSTS (OSCCON<3>) and T1RUN

(T1CON<6>). In general, only one of these bits will be

set while in a given power-managed mode. When the

OSTS bit is set, the primary clock is providing the

device clock. When the T1RUN bit is set, the Timer1

oscillator is providing the clock. If neither of these bits

is set, INTRC is clocking the device.

3.1.4 MULTIPLE SLEEP COMMANDS

The power-managed mode that is invoked with the

SLEEP instruction is determined by the setting of the

IDLEN bit at the time the instruction is executed. If

another SLEEP instruction is executed, the device will

enter the power-managed mode specified by IDLEN at

that time. If IDLEN has changed, the device will enter

the new power-managed mode specified by the new

setting.

3.2 Run Modes

In the Run modes, clocks to both the core and

peripherals are active. The difference between these

modes is the clock source.

3.2.1 PRI_RUN MODE

The PRI_RUN mode is the normal, full-power execu-

tion mode of the microcontroller. This is also the default

mode upon a device Reset unless Two-Speed Start-up

is enabled (see Section 25.4 “Two-Speed Start-up”

for details). In this mode, the OSTS bit is set. (see

Section 2.4.1 “Oscillator Control Register”).

3.2.2 SEC_RUN MODE

The SEC_RUN mode is the compatible mode to the

“clock switching” feature offered in other PIC18

devices. In this mode, the CPU and peripherals are

clocked from the Timer1 oscillator. This gives users the

option of lower power consumption while still using a

high-accuracy clock source.

SEC_RUN mode is entered by setting the SCS1:SCS0

bits to ‘01’. The device clock source is switched to the

Timer1 oscillator (see Figure 3-1), the primary oscilla-

tor is shut down, the T1RUN bit (T1CON<6>) is set and

the OSTS bit is cleared.

Note: Executing a SLEEP instruction does not

necessarily place the device into Sleep

mode. It acts as the trigger to place the

controller into either the Sleep mode, or

one of the Idle modes, depending on the

setting of the IDLEN bit.

PIC18F87J50 FAMILY

On transitions from SEC_RUN mode to PRI_RUN

mode, the peripherals and CPU continue to be clocked

from the Timer1 oscillator while the primary clock is

started. When the primary clock becomes ready, a

clock switch back to the primary clock occurs (see

Figure 3-2). When the clock switch is complete, the

T1RUN bit is cleared, the OSTS bit is set and the

primary clock is providing the clock. The IDLEN and

SCS bits are not affected by the wake-up; the Timer1

oscillator continues to run.

FIGURE 3-1: TRANSITION TIMING FOR ENTRY TO SEC_RUN MODE

FIGURE 3-2: TRANSITION TIMING FROM SEC_RUN MODE TO PRI_RUN MODE (HSPLL)

Note: The Timer1 oscillator should already be

running prior to entering SEC_RUN mode.

If the T1OSCEN bit is not set when the

SCS1:SCS0 bits are set to ‘01’, entry to

SEC_RUN mode will not occur. If the

Timer1 oscillator is enabled, but not yet

running, device clocks will be delayed until

the oscillator has started. In such situa-

tions, initial oscillator operation is far from

stable and unpredictable operation may

result.

Q4Q3Q2

OSC1

Peripheral

Program

T1OSI

Counter

Clock

CPU

Clock

PC + 2PC

123

n-1

Clock Transition

Q4Q3Q2 Q1 Q3Q2

PC + 4

Q1 Q3 Q4

OSC1

Peripheral

Program PC

T1OSI

PLL Clock

PC + 4

Output

Q3 Q4 Q1

CPU Clock

PC + 2

Clock

Counter

Q2 Q2 Q3

Note 1: TOST = 1024 TOSC; TPLL = 2 ms (approx). These intervals are not shown to scale.

SCS1:SCS0 Bits Changed

TPLL(1)

12 n-1n

Clock

OSTS Bit Set

Transition

TOST(1)

PIC18F87J50 FAMILY

3.2.3 RC_RUN MODE

In RC_RUN mode, the CPU and peripherals are

clocked from the internal oscillator; the primary clock is

shut down. This mode provides the best power conser-

vation of all the Run modes while still executing code.

It works well for user applications which are not highly

timing sensitive or do not require high-speed clocks at

all times.

This mode is entered by setting the SCS1:SCS0 bits

(OSCCON<1:0>) to ‘11’. When the clock source is

switched to the internal oscillator block (see

Figure 3-3), the primary oscillator is shut down and the

OSTS bit is cleared.

On transitions from RC_RUN mode to PRI_RUN mode,

the device continues to be clocked from the INTOSC

block while the primary clock is started. When the

primary clock becomes ready, a clock switch to the

primary clock occurs (see Figure 3-4). When the clock

switch is complete, the OSTS bit is set and the primary

clock is providing the device clock. The IDLEN and

SCS bits are not affected by the switch. The INTRC

block source will continue to run if either the WDT or the

Fail-Safe Clock Monitor is enabled.

FIGURE 3-3: TRANSITION TIMING TO RC_RUN MODE

FIGURE 3-4: TRANSITION TIMING FROM RC_RUN MODE TO PRI_RUN MODE

Q4Q3Q2

OSC1

Peripheral

Program

INTRC

Counter

Clock

CPU

Clock

PC + 2PC

123 n-1n

Clock Transition

Q4Q3Q2 Q1 Q3Q2

PC + 4

Q1 Q3 Q4

OSC1

Peripheral

Program PC

INTRC

PLL Clock

PC + 4

Output

Q3 Q4 Q1

CPU Clock

PC + 2

Clock

Counter

Q2 Q2 Q3

Note 1: TOST = 1024 TOSC; TPLL = 2 ms (approx). These intervals are not shown to scale.

SCS1:SCS0 Bits Changed

TPLL(1)

12 n-1n

Clock

OSTS Bit Set

Transition

TOST(1)

PIC18F87J50 FAMILY

3.3 Sleep Mode

The power-managed Sleep mode is identical to the leg-

acy Sleep mode offered in all other PIC devices. It is

entered by clearing the IDLEN bit (the default state on

device Reset) and executing the SLEEP instruction.

This shuts down the selected oscillator (Figure 3-5). All

clock source status bits are cleared.

Entering the Sleep mode from any other mode does not

require a clock switch. This is because no clocks are

needed once the controller has entered Sleep. If the

WDT is selected, the INTRC source will continue to

operate. If the Timer1 oscillator is enabled, it will also

continue to run.

When a wake event occurs in Sleep mode (by interrupt,

Reset or WDT time-out), the device will not be clocked

until the clock source selected by the SCS1:SCS0 bits

becomes ready (see Figure 3-6), or it will be clocked

from the internal oscillator if either the Two-Speed

Start-up or the Fail-Safe Clock Monitor are enabled

(see Section 25.0 “Special Features of the CPU”). In

either case, the OSTS bit is set when the primary clock

is providing the device clocks. The IDLEN and SCS bits

are not affected by the wake-up.

3.4 Idle Modes

The Idle modes allow the controller’s CPU to be

selectively shut down while the peripherals continue to

operate. Selecting a particular Idle mode allows users

to further manage power consumption.

If the IDLEN bit is set to ‘1’ when a SLEEP instruction is

executed, the peripherals will be clocked from the clock

source selected using the SCS1:SCS0 bits; however, the

CPU will not be clocked. The clock source status bits are

not affected. Setting IDLEN and executing a SLEEP

instruction provides a quick method of switching from a

given Run mode to its corresponding Idle mode.

If the WDT is selected, the INTRC source will continue

to operate. If the Timer1 oscillator is enabled, it will also

continue to run.

Since the CPU is not executing instructions, the only

exits from any of the Idle modes are by interrupt, WDT

time-out or a Reset. When a wake event occurs, CPU

execution is delayed by an interval of TCSD

(parameter 38, Table 28-13) while it becomes ready to

execute code. When the CPU begins executing code,

it resumes with the same clock source for the current

Idle mode. For example, when waking from RC_IDLE

mode, the internal oscillator block will clock the CPU

and peripherals (in other words, RC_RUN mode). The

IDLEN and SCS bits are not affected by the wake-up.

While in any Idle mode or the Sleep mode, a WDT

time-out will result in a WDT wake-up to the Run mode

currently specified by the SCS1:SCS0 bits.

FIGURE 3-5: TRANSITION TIMING FOR ENTRY TO SLEEP MODE

FIGURE 3-6: TRANSITION TIMING FOR WAKE FROM SLEEP (HSPLL)

Q4Q3Q2

OSC1

Peripheral

Sleep

Program

Q1Q1

Counter

Clock

CPU

Clock

PC + 2PC

Q3 Q4 Q1 Q2

OSC1

Peripheral

Program PC

PLL Clock

Q3 Q4

Output

CPU Clock

Q1 Q2 Q3 Q4 Q1 Q2

Clock

Counter PC + 6PC + 4

Q1 Q2 Q3 Q4

Wake Event

Note1: TOST = 1024 TOSC; TPLL = 2 ms (approx). These intervals are not shown to scale.

TOST(1) TPLL(1)

OSTS Bit Set

PC + 2

PIC18F87J50 FAMILY

3.4.1 PRI_IDLE MODE

This mode is unique among the three low-power Idle

modes, in that it does not disable the primary device

clock. For timing sensitive applications, this allows for

the fastest resumption of device operation with its more

accurate primary clock source, since the clock source

does not have to “warm up” or transition from another

oscillator.

PRI_IDLE mode is entered from PRI_RUN mode by

setting the IDLEN bit and executing a SLEEP instruc-

tion. If the device is in another Run mode, set IDLEN

first, then set the SCS bits to ‘00’ and execute SLEEP.

Although the CPU is disabled, the peripherals continue

to be clocked from the primary clock source specified

by the FOSC1:FOSC0 Configuration bits. The OSTS

bit remains set (see Figure 3-7).

When a wake event occurs, the CPU is clocked from the

primary clock source. A delay of interval TCSD is

required between the wake event and when code exe-

cution starts. This is required to allow the CPU to

become ready to execute instructions. After the

wake-up, the OSTS bit remains set. The IDLEN and

SCS bits are not affected by the wake-up (see

Figure 3-8).

3.4.2 SEC_IDLE MODE

In SEC_IDLE mode, the CPU is disabled but the

peripherals continue to be clocked from the Timer1

oscillator. This mode is entered from SEC_RUN by set-

ting the IDLEN bit and executing a SLEEP instruction. If

the device is in another Run mode, set IDLEN first, then

set SCS1:SCS0 to ‘01’ and execute SLEEP. When the

clock source is switched to the Timer1 oscillator, the

primary oscillator is shut down, the OSTS bit is cleared

and the T1RUN bit is set.

When a wake event occurs, the peripherals continue to

be clocked from the Timer1 oscillator. After an interval

of TCSD following the wake event, the CPU begins exe-

cuting code being clocked by the Timer1 oscillator. The

IDLEN and SCS bits are not affected by the wake-up;

the Timer1 oscillator continues to run (see Figure 3-8).

FIGURE 3-7: TRANSITION TIMING FOR ENTRY TO IDLE MODE

FIGURE 3-8: TRANSITION TIMING FOR WAKE FROM IDLE TO RUN MODE

Note: The Timer1 oscillator should already be

running prior to entering SEC_IDLE mode.

If the T1OSCEN bit is not set when the

SLEEP instruction is executed, the SLEEP

instruction will be ignored and entry to

SEC_IDLE mode will not occur. If the

Timer1 oscillator is enabled, but not yet

running, peripheral clocks will be delayed

until the oscillator has started. In such

situations, initial oscillator operation is far

from stable and unpredictable operation

may result.

Peripheral

Program PC PC + 2

OSC1

Q3 Q4 Q1

CPU Clock

Clock

Counter

OSC1

Peripheral

Program PC

CPU Clock

Q1 Q3 Q4

Clock

Counter

Wake Event

TCSD

PIC18F87J50 FAMILY

3.4.3 RC_IDLE MODE

In RC_IDLE mode, the CPU is disabled but the

peripherals continue to be clocked from the internal

oscillator block. This mode allows for controllable

power conservation during Idle periods.

From RC_RUN, this mode is entered by setting the

IDLEN bit and executing a SLEEP instruction. If the

device is in another Run mode, first set IDLEN, then

clear the SCS bits and execute SLEEP. When the clock

source is switched to the INTOSC block, the primary

oscillator is shut down and the OSTS bit is cleared.

When a wake event occurs, the peripherals continue to

be clocked from the internal oscillator block. After a

delay of TCSD following the wake event, the CPU

begins executing code being clocked by the INTRC.

The IDLEN and SCS bits are not affected by the

wake-up. The INTRC source will continue to run if

either the WDT or the Fail-Safe Clock Monitor is

enabled.

3.5 Exiting Idle and Sleep Modes

An exit from Sleep mode, or any of the Idle modes, is

triggered by an interrupt, a Reset or a WDT time-out.

This section discusses the triggers that cause exits

from power-managed modes. The clocking subsystem

actions are discussed in each of the power-managed

modes sections (see Section 3.2 “Run Modes”,

Section 3.3 “Sleep Mode” and Section 3.4 “Idle

Modes”).

3.5.1 EXIT BY INTERRUPT

Any of the available interrupt sources can cause the

device to exit from an Idle mode, or the Sleep mode, to

a Run mode. To enable this functionality, an interrupt

source must be enabled by setting its enable bit in one

of the INTCON or PIE registers. The exit sequence is

initiated when the corresponding interrupt flag bit is set.

On all exits from Idle or Sleep modes by interrupt, code

execution branches to the interrupt vector if the

GIE/GIEH bit (INTCON<7>) is set. Otherwise, code

execution continues or resumes without branching

(see Section 9.0 “Interrupts”).

A fixed delay of interval, TCSD, following the wake event

is required when leaving Sleep and Idle modes. This

delay is required for the CPU to prepare for execution.

Instruction execution resumes on the first clock cycle

following this delay.

3.5.2 EXIT BY WDT TIME-OUT

A WDT time-out will cause different actions depending

on which power-managed mode the device is in when

the time-out occurs.

If the device is not executing code (all Idle modes and

Sleep mode), the time-out will result in an exit from the

power-managed mode (see Section 3.2 “Run

Modes” and Section 3.3 “Sleep Mode”). If the device

is executing code (all Run modes), the time-out will

result in a WDT Reset (see Section 25.2 “Watchdog

Timer (WDT)”).

The Watchdog Timer and postscaler are cleared by one

of the following events:

• Executing a SLEEP or CLRWDT instruction

• The loss of a currently selected clock source (if

the Fail-Safe Clock Monitor is enabled)

3.5.3 EXIT BY RESET

Exiting an Idle or Sleep mode by Reset automatically

forces the device to run from the INTRC.

3.5.4 EXIT WITHOUT AN OSCILLATOR

START-UP DELAY

Certain exits from power-managed modes do not

invoke the OST at all. There are two cases:

• PRI_IDLE mode, where the primary clock source

is not stopped; and

• the primary clock source is either the EC or

ECPLL mode.

In these instances, the primary clock source either

does not require an oscillator start-up delay, since it is

already running (PRI_IDLE), or normally does not

require an oscillator start-up delay (EC). However, a

fixed delay of interval, T

CSD, following the wake event

is still required when leaving Sleep and Idle modes to

allow the CPU to prepare for execution. Instruction

execution resumes on the first clock cycle following this

delay.

PIC18F87J50 FAMILY

NOTES:

PIC18F87J50 FAMILY

4.0 RESET

The PIC18F87J10 family of devices differentiate

between various kinds of Reset:

a) Power-on Reset (POR)

b) MCLR Reset during normal operation

c) MCLR Reset during power-managed modes

d) Watchdog Timer (WDT) Reset (during

execution)

e) Configuration Mismatch (CM)

f) Brown-out Reset (BOR)

g) RESET Instruction

h) Stack Full Reset

i) Stack Underflow Reset

This section discusses Resets generated by MCLR,

POR and BOR, and covers the operation of the various

start-up timers. Stack Reset events are covered in

Section 5.1.6.4 “Stack Full and Underflow Resets”.

WDT Resets are covered in Section 25.2 “Watchdog

Timer (WDT)”.

A simplified block diagram of the on-chip Reset circuit

is shown in Figure 4-1.

4.1 RCON Register

Device Reset events are tracked through the RCON

occurred. In most cases, these bits can only be set by

the event and must be cleared by the application after

the event. The state of these flag bits, taken together,

can be read to indicate the type of Reset that just

occurred. This is described in more detail in

Section 4.7 “Reset State of Registers”.

The RCON register also has a control bit for setting

interrupt priority (IPEN). Interrupt priority is discussed

in Section 9.0 “Interrupts”.

FIGURE 4-1: SIMPLIFIED BLOCK DIAGRAM OF ON-CHIP RESET CIRCUIT

External Reset

MCLR

VDD

WDT

Time-out

VDD Rise

Detect

PWRT

INTRC

POR Pulse

Chip_Reset

Brown-out

Reset(1)

RESET Instruction

Stack

Pointer

Stack Full/Underflow Reset

Sleep

( )_IDLE

32 μs

Note 1: The ENVREG pin must be tied high to enable Brown-out Reset. The Brown-out Reset is provided by the on-chip

voltage regulator when there is insufficient source voltage to function properly.

PWRT

11-Bit Ripple Counter

66 ms

Configuration Word Mismatch

PIC18F87J50 FAMILY

R/W-0 U-0 R/W-1 R/W-1 R-1 R-1 R/W-0 R/W-0

IPEN —CMRI TO PD POR BOR

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 IPEN: Interrupt Priority Enable bit

1 = Enable priority levels on interrupts

0 = Disable priority levels on interrupts (PIC16CXXX Compatibility mode)

bit 6 Unimplemented: Read as ‘0’

bit 5 CM: Configuration Mismatch Flag bit

1 = A Configuration Mismatch Reset has not occurred

0 = A Configuration Mismatch Reset has occurred (must be set in software after a Configuration

Mismatch Reset occurs)

bit 4 RI: RESET Instruction Flag bit

1 = The RESET instruction was not executed (set by firmware only)

0 = The RESET instruction was executed causing a device Reset (must be set in software after a

Brown-out Reset occurs)

bit 3 TO: Watchdog Time-out Flag bit

1 = Set by power-up, CLRWDT instruction or SLEEP instruction

0 = A WDT time-out occurred

bit 2 PD: Power-Down Detection Flag bit

1 = Set by power-up or by the CLRWDT instruction

0 = Set by execution of the SLEEP instruction

bit 1 POR: Power-on Reset Status bit

1 = A Power-on Reset has not occurred (set by firmware only)

0 = A Power-on Reset occurred (must be set in software after a Power-on Reset occurs)

bit 0 BOR: Brown-out Reset Status bit

1 = A Brown-out Reset has not occurred (set by firmware only)

0 = A Brown-out Reset occurred (must be set in software after a Brown-out Reset occurs)

Note 1: It is recommended that the POR bit be set after a Power-on Reset has been detected, so that subsequent

Power-on Resets may be detected.

2: If the on-chip voltage regulator is disabled, BOR remains ‘0’ at all times. See Section 4.4.1 “Detecting

BOR” for more information.

3: Brown-out Reset is said to have occurred when BOR is ‘0’ and POR is ‘1’ (assuming that POR was set to

‘1’ by software immediately after a Power-on Reset).

PIC18F87J50 FAMILY

4.2 Master Clear (MCLR)

The MCLR pin provides a method for triggering a hard

external Reset of the device. A Reset is generated by

holding the pin low. PIC18 extended microcontroller

devices have a noise filter in the MCLR Reset path

which detects and ignores small pulses.

The MCLR pin is not driven low by any internal Resets,

including the WDT.

4.3 Power-on Reset (POR)

A Power-on Reset condition is generated on-chip

whenever VDD rises above a certain threshold. This

allows the device to start in the initialized state when

VDD is adequate for operation.

To take advantage of the POR circuitry, tie the MCLR

pin through a resistor (1 kΩ to 10 kΩ) to VDD. This will

eliminate external RC components usually needed to

create a Power-on Reset delay. A minimum rise rate for

VDD is specified (parameter D004). For a slow rise

time, see Figure 4-2.

When the device starts normal operation (i.e., exits the

Reset condition), device operating parameters

(voltage, frequency, temperature, etc.) must be met to

ensure operation. If these conditions are not met, the

device must be held in Reset until the operating

conditions are met.

POR events are captured by the POR bit (RCON<1>).

The state of the bit is set to ‘0’ whenever a Power-on

Reset occurs; it does not change for any other Reset

event. POR is not reset to ‘1’ by any hardware event.

To capture multiple events, the user manually resets

the bit to ‘1’ in software following any Power-on Reset.

4.4 Brown-out Reset (BOR)

The PIC18F87J10 family of devices incorporates a

simple BOR function when the internal regulator is

enabled (ENVREG pin is tied to VDD). Any drop of VDD

below VBOR (parameter D005) for greater than time

TBOR (parameter 35) will reset the device. A Reset may

or may not occur if VDD falls below VBOR for less than

TBOR. The chip will remain in Brown-out Reset until

VDD rises above VBOR.

Once a BOR has occurred, the Power-up Timer will

keep the chip in Reset for TPWRT (parameter 33). If

VDD drops below VBOR while the Power-up Timer is

running, the chip will go back into a Brown-out Reset

and the Power-up Timer will be initialized. Once VDD

rises above VBOR, the Power-up Timer will execute the

additional time delay.

FIGURE 4-2: EXTERNAL POWER-ON

RESET CIRCUIT (FOR

SLOW VDD POW ER-UP)

4.4.1 DETECTING BOR

The BOR bit always resets to ‘0’ on any Brown-out

Reset or Power-on Reset event. This makes it difficult

to determine if a Brown-out Reset event has occurred

just by reading the state of BOR alone. A more reliable

method is to simultaneously check the state of both

POR and BOR. This assumes that the POR bit is reset

to ‘1’ in software immediately after any Power-on Reset

event. If BOR is ‘0’ while POR is ‘1’, it can be reliably

assumed that a Brown-out Reset event has occurred.

If the voltage regulator is disabled, Brown-out Reset

functionality is disabled. In this case, the BOR bit

cannot be used to determine a Brown-out Reset event.

The BOR bit is still cleared by a Power-on Reset event.

4.5 Configuration Mismatch (CM)

The Configuration Mismatch (CM) Reset is designed to

detect and attempt to recover from random, memory

corrupting events. These include Electrostatic

Discharge (ESD) events, which can cause widespread

single-bit changes throughout the device, and result in

catastrophic failure.

In PIC18FXXJ Flash devices, the device Configuration

registers (located in the configuration memory space)

are continuously monitored during operation by com-

paring their values to complimentary shadow registers.

If a mismatch is detected between the two sets of

registers, a CM Reset automatically occurs. These

events are captured by the CM bit (RCON<5>). The

state of the bit is set to ‘0’ whenever a CM event occurs;

it does not change for any other Reset event.

Note 1: External Power-on Reset circuit is required

only if the VDD power-up slope is too slow.

The diode D helps discharge the capacitor

quickly when VDD powers down.

2: R < 40 kΩ is recommended to make sure that

the voltage drop across R does not violate

the device’s electrical specification.

3: R1 ≥ 1 kΩ will limit any current flowing into

MCLR from external capacitor C, in the event

of MCLR/VPP pin breakdown, due to

Electrostatic Discharge (ESD) or Electrical

Overstress (EOS).

VDD

MCLR

PIC18F87J50

VDD

PIC18F87J50 FAMILY

A CM Reset behaves similarly to a Master Clear Reset,

RESET instruction, WDT time-out or Stack Event

Resets. As with all hard and power Reset events, the

device Configuration Words are reloaded from the

Flash Configuration Words in program memory as the

device restarts.

4.6 Power-up Timer (PWRT)

PIC18F87J10 family devices incorporate an on-chip

Power-up Timer (PWRT) to help regulate the Power-on

Reset process. The PWRT is always enabled. The

main function is to ensure that the device voltage is

stable before code is executed.

The Power-up Timer (PWRT) of the PIC18F87J10 fam-

ily devices is an 11-bit counter which uses the INTRC

source as the clock input. This yields an approximate

time interval of 2048 x 32 μs = 66 ms. While the PWRT

is counting, the device is held in Reset.

The power-up time delay depends on the INTRC clock

and will vary from chip-to-chip due to temperature and

process variation. See DC parameter 33 for details.

4.6.1 TIME-OUT SEQUENCE

The PWRT time-out is invoked after the POR pulse has

cleared. The total time-out will vary based on the status

of the PWRT. Figure 4-3, Figure 4-4, Figure 4-5 and

Figure 4-6 all depict time-out sequences on power-up

with the Power-up Timer.

Since the time-outs occur from the POR pulse, if MCLR

is kept low long enough, the PWRT will expire. Bringing

MCLR high will begin execution immediately if a clock

source is available (Figure 4-5). This is useful for

testing purposes, or to synchronize more than one

PIC18FXXXX device operating in parallel.

FIGURE 4-3: TIME-OUT SEQUENCE ON POWER-UP (MCLR TIED TO VDD, VDD RISE < TPWRT)

FIGURE 4-4: TIME-OUT SEQUENCE ON POWER-UP (MCLR NOT TIED TO VDD): CASE 1

TPWRT

VDD

MCLR

INTERNAL POR

PWRT TIME-OUT

INTERNAL RESET

TPWRT

VDD

MCLR

INTERNAL POR

PWRT TIME-OUT

INTERNAL RESET

PIC18F87J50 FAMILY

FIGURE 4-5: TIME-OUT SEQUENCE ON POWER-UP (MCLR NOT TIED TO VDD): CASE 2

FIGURE 4-6: SLOW RISE TIME (MCLR TIED TO VDD, VDD RISE > TPWRT)

VDD

MCLR

INTERNAL POR

PWRT TIME-OUT

INTERNAL RESET

TPWRT

VDD

MCLR

INTERNAL POR

PWRT TIME-OUT

INTERNAL RESET

0V 1V

3.3V

TPWRT

PIC18F87J50 FAMILY

4.7 Reset State of Registers

Most registers are unaffected by a Reset. Their status

is unknown on POR and unchanged by all other

Resets. The other registers are forced to a “Reset

state” depending on the type of Reset that occurred.

Most registers are not affected by a WDT wake-up,

since this is viewed as the resumption of normal

operation. Status bits from the RCON register (CM, RI,

TO, PD, POR and BOR) are set or cleared differently in

different Reset situations, as indicated in Table 4-1.

These bits are used in software to determine the nature

of the Reset.

Table 4-2 describes the Reset states for all of the

Special Function Registers. These are categorized by

Power-on and Brown-out Resets, Master Clear and

WDT Resets and WDT wake-ups.

TABLE 4-1: STATUS BITS, THEIR SIGNIFICANCE AND THE INITIALIZATION CONDITION FOR

RCON REGISTER

Condition Program

Counter(1)

RCON Register STKPTR Register

CM RI TO PD POR BOR STKFUL STKUNF

Power-on Reset 0000h 111100 0 0

RESET instruction 0000h u0uuuu u u

Brown-out Reset 0000h 1111u0 u u

Configuration Mismatch Reset 0000h 0uuuuu u u

MCLR Reset during

power-managed Run modes

0000h uu1uuu u u

MCLR Reset during

power-managed Idle modes and

Sleep mode

0000h uu10uu u u

MCLR Reset during full-power

execution

0000h uuuuuu u u

Stack Full Reset (STVREN = 1) 0000h uuuuuu 1 u

Stack Underflow Reset

(STVREN = 1)

0000h uuuuuu u 1

Stack Underflow Error (not an

actual Reset, STVREN = 0)

0000h uuuuuu u 1

WDT time-out during full-power

or power-managed Run modes

0000h uu0uuu u u

WDT time-out during

power-managed Idle or Sleep

modes

PC + 2 uu00uu u u

Interrupt exit from

power-managed modes

PC + 2 uuu0uu u u

Legend: u = unchanged

Note 1: When the wake-up is due to an interrupt and the GIEH or GIEL bit is set, the PC is loaded with the interrupt

vector (0008h or 0018h).

PIC18F87J50 FAMILY

TABLE 4-2: INITIALIZATION CONDITIONS FOR ALL REGISTERS

Brown-out Reset

MCLR Resets

WDT Reset

RESET Instruction

Stack Resets

CM Resets

Wake-up via WDT

or Interrupt

TOSU Feature1 PIC18F8XJ5X ---0 0000 ---0 0000 ---0 uuuu(1)

TOSH Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu(1)

TOSL Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu(1)

STKPTR Feature1 PIC18F8XJ5X 00-0 0000 uu-0 0000 uu-u uuuu(1)

PCLATU Feature1 PIC18F8XJ5X ---0 0000 ---0 0000 ---u uuuu

PCLATH Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

PCL Feature1 PIC18F8XJ5X 0000 0000 0000 0000 PC + 2(2)

TBLPTRU Feature1 PIC18F8XJ5X --00 0000 --00 0000 --uu uuuu

TBLPTRH Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

TBLPTRL Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

TABLAT Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

PRODH Feature1 PIC18F8XJ5X xxxx xxxx uuuu uuuu uuuu uuuu

PRODL Feature1 PIC18F8XJ5X xxxx xxxx uuuu uuuu uuuu uuuu

INTCON Feature1 PIC18F8XJ5X 0000 000x 0000 000u uuuu uuuu(3)

INTCON2 Feature1 PIC18F8XJ5X 1111 1111 1111 1111 uuuu uuuu(3)

INTCON3 Feature1 PIC18F8XJ5X 1100 0000 1100 0000 uuuu uuuu(3)

INDF0 Feature1 PIC18F8XJ5X N/A N/A N/A

POSTINC0 Feature1 PIC18F8XJ5X N/A N/A N/A

POSTDEC0 Feature1 PIC18F8XJ5X N/A N/A N/A

PREINC0 Feature1 PIC18F8XJ5X N/A N/A N/A

PLUSW0 Feature1 PIC18F8XJ5X N/A N/A N/A

FSR0H Feature1 PIC18F8XJ5X ---- xxxx ---- uuuu ---- uuuu

FSR0L Feature1 PIC18F8XJ5X xxxx xxxx uuuu uuuu uuuu uuuu

WREG Feature1 PIC18F8XJ5X xxxx xxxx uuuu uuuu uuuu uuuu

INDF1 Feature1 PIC18F8XJ5X N/A N/A N/A

POSTINC1 Feature1 PIC18F8XJ5X N/A N/A N/A

POSTDEC1 Feature1 PIC18F8XJ5X N/A N/A N/A

PREINC1 Feature1 PIC18F8XJ5X N/A N/A N/A

PLUSW1 Feature1 PIC18F8XJ5X N/A N/A N/A

FSR1H Feature1 PIC18F8XJ5X ---- xxxx ---- uuuu ---- uuuu

FSR1L Feature1 PIC18F8XJ5X xxxx xxxx uuuu uuuu uuuu uuuu

BSR Feature1 PIC18F8XJ5X ---- 0000 ---- 0000 ---- uuuu

Legend: u = unchanged, x = unknown, - = unimplemented bit, read as ‘0’, q = value depends on condition.

Shaded cells indicate conditions do not apply for the designated device.

Note 1: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are

updated with the current value of the PC. The STKPTR is modified to point to the next location in the

hardware stack.

2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the interrupt

vector (0008h or 0018h).

3: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).

4: See Table 4-1 for Reset value for specific condition.

PIC18F87J50 FAMILY

INDF2 Feature1 PIC18F8XJ5X N/A N/A N/A

POSTINC2 Feature1 PIC18F8XJ5X N/A N/A N/A

POSTDEC2 Feature1 PIC18F8XJ5X N/A N/A N/A

PREINC2 Feature1 PIC18F8XJ5X N/A N/A N/A

PLUSW2 Feature1 PIC18F8XJ5X N/A N/A N/A

FSR2H Feature1 PIC18F8XJ5X ---- xxxx ---- uuuu ---- uuuu

FSR2L Feature1 PIC18F8XJ5X xxxx xxxx uuuu uuuu uuuu uuuu

STATUS Feature1 PIC18F8XJ5X ---x xxxx ---u uuuu ---u uuuu

TMR0H Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

TMR0L Feature1 PIC18F8XJ5X xxxx xxxx uuuu uuuu uuuu uuuu

T0CON Feature1 PIC18F8XJ5X 1111 1111 1111 1111 uuuu uuuu

OSCCON Feature1 PIC18F8XJ5X 0110 q100 0110 q100 0110 q10u

REFOCON Feature1 PIC18F8XJ5X 0-00 0000 u-uu uuuu u-uu uuuu

CM1CON Feature1 PIC18F8XJ5X 0001 1111 uuuu uuuu uuuu uuuu

CM2CON Feature1 PIC18F8XJ5X 0001 1111 uuuu uuuu uuuu uuuu

RCON(4) Feature1 PIC18F8XJ5X 0-11 1100 0-qq qquu u-qq qquu

TMR1H Feature1 PIC18F8XJ5X xxxx xxxx uuuu uuuu uuuu uuuu

ODCON1 Feature1 PIC18F8XJ5X ---0 0000 ---u uuuu ---u uuuu

TMR1L Feature1 PIC18F8XJ5X xxxx xxxx uuuu uuuu uuuu uuuu

ODCON2 Feature1 PIC18F8XJ5X ---- --00 ---- --uu ---- --uu

T1CON Feature1 PIC18F8XJ5X 0000 0000 u0uu uuuu uuuu uuuu

ODCON3 Feature1 PIC18F8XJ5X ---- --00 ---- --uu ---- --uu

TMR2 Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

PADCFG1 Feature1 PIC18F8XJ5X ---- ---0 ---- ---u ---- ---u

PR2 Feature1 PIC18F8XJ5X 1111 1111 1111 1111 1111 1111

MEMCON Feature1 PIC18F8XJ5X 0-00 --00 0-00 --00 u-uu --uu

T2CON Feature1 PIC18F8XJ5X -000 0000 -000 0000 -uuu uuuu

SSP1BUF Feature1 PIC18F8XJ5X xxxx xxxx uuuu uuuu uuuu uuuu

SSP1ADD Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

SSP1MSK Feature1 PIC18F8XJ5X 1111 1111 uuuu uuuu uuuu uuuu

SSP1STAT Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

SSP1CON1 Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

SSP1CON2 Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

TABLE 4-2: INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)

Brown-out Reset

MCLR Resets

WDT Reset

RESET Instruction

Stack Resets

CM Resets

Wake-up via WDT

or Interrupt

Legend: u = unchanged, x = unknown, - = unimplemented bit, read as ‘0’, q = value depends on condition.

Shaded cells indicate conditions do not apply for the designated device.

Note 1: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are

updated with the current value of the PC. The STKPTR is modified to point to the next location in the

hardware stack.

2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the interrupt

vector (0008h or 0018h).

3: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).

4: See Table 4-1 for Reset value for specific condition.

PIC18F87J50 FAMILY

ADRESH Feature1 PIC18F8XJ5X xxxx xxxx uuuu uuuu uuuu uuuu

ADRESL Feature1 PIC18F8XJ5X xxxx xxxx uuuu uuuu uuuu uuuu

ADCON0 Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

ADCON1 Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

ANCON0 Feature1 PIC18F8XJ5X 0--0 0000 u--u uuuu u--u uuuu

ANCON1 Feature1 PIC18F8XJ5X 0000 00-- uuuu uu-- uuuu uu--

WDTCON Feature1 PIC18F8XJ5X 0x-0 ---0 0x-u ---0 ux-u ---u

ECCP1AS Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

ECCP1DEL Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

CCPR1H Feature1 PIC18F8XJ5X xxxx xxxx uuuu uuuu uuuu uuuu

CCPR1L Feature1 PIC18F8XJ5X xxxx xxxx uuuu uuuu uuuu uuuu

CCP1CON Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

ECCP2AS Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

ECCP2DEL Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

CCPR2H Feature1 PIC18F8XJ5X xxxx xxxx uuuu uuuu uuuu uuuu

CCPR2L Feature1 PIC18F8XJ5X xxxx xxxx uuuu uuuu uuuu uuuu

CCP2CON Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

ECCP3AS Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

ECCP3DEL Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

CCPR3H Feature1 PIC18F8XJ5X xxxx xxxx uuuu uuuu uuuu uuuu

CCPR3L Feature1 PIC18F8XJ5X xxxx xxxx uuuu uuuu uuuu uuuu

CCP3CON Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

SPBRG1 Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

RCREG1 Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

TXREG1 Feature1 PIC18F8XJ5X xxxx xxxx uuuu uuuu uuuu uuuu

TXSTA1 Feature1 PIC18F8XJ5X 0000 0010 0000 0010 uuuu uuuu

RCSTA1 Feature1 PIC18F8XJ5X 0000 000x 0000 000x uuuu uuuu

SPBRG2 Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

RCREG2 Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

TXREG2 Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

TXSTA2 Feature1 PIC18F8XJ5X 0000 0010 0000 0010 uuuu uuuu

EECON2 Feature1 PIC18F8XJ5X ---- ---- ---- ---- ---- ----

EECON1 Feature1 PIC18F8XJ5X --00 x00- --00 u00- --00 u00-

TABLE 4-2: INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)

Brown-out Reset

MCLR Resets

WDT Reset

RESET Instruction

Stack Resets

CM Resets

Wake-up via WDT

or Interrupt

Legend: u = unchanged, x = unknown, - = unimplemented bit, read as ‘0’, q = value depends on condition.

Shaded cells indicate conditions do not apply for the designated device.

Note 1: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are

updated with the current value of the PC. The STKPTR is modified to point to the next location in the

hardware stack.

2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the interrupt

vector (0008h or 0018h).

3: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).

4: See Table 4-1 for Reset value for specific condition.

PIC18F87J50 FAMILY

IPR3 Feature1 PIC18F8XJ5X 1111 1111 1111 1111 uuuu uuuu

PIR3 Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu(3)

PIE3 Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

IPR2 Feature1 PIC18F8XJ5X 1111 1111 1111 1111 uuuu uuuu

PIR2 Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu(3)

PIE2 Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

IPR1 Feature1 PIC18F8XJ5X 1111 1111 1111 1111 uuuu uuuu

PIR1 Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu(3)

PIE1 Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

RCSTA2 Feature1 PIC18F8XJ5X 0000 000x 0000 000x uuuu uuuu

OSCTUNE Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

TRISJ Feature1 PIC18F8XJ5X 1111 1111 1111 1111 uuuu uuuu

TRISH Feature1 PIC18F8XJ5X 1111 1111 1111 1111 uuuu uuuu

TRISG Feature1 PIC18F8XJ5X ---1 1111 ---1 1111 ---u uuuu

TRISF Feature1 PIC18F8XJ5X 111- -1-- 111- -1-- uuu- -u--

TRISE Feature1 PIC18F8XJ5X 1111 1111 1111 1111 uuuu uuuu

TRISD Feature1 PIC18F8XJ5X 1111 1111 1111 1111 uuuu uuuu

TRISC Feature1 PIC18F8XJ5X 1111 1111 1111 1111 uuuu uuuu

TRISB Feature1 PIC18F8XJ5X 1111 1111 1111 1111 uuuu uuuu

TRISA Feature1 PIC18F8XJ5X --11 1111 --11 1111 --uu uuuu

LATJ Feature1 PIC18F8XJ5X xxxx xxxx uuuu uuuu uuuu uuuu

LATH Feature1 PIC18F8XJ5X xxxx xxxx uuuu uuuu uuuu uuuu

LATG Feature1 PIC18F8XJ5X ---x xxxx ---u uuuu ---u uuuu

LATF Feature1 PIC18F8XJ5X xxxx xx-- uuuu uu-- uuuu uu--

LATE Feature1 PIC18F8XJ5X xxxx xxxx uuuu uuuu uuuu uuuu

LATD Feature1 PIC18F8XJ5X xxxx xxxx uuuu uuuu uuuu uuuu

LATC Feature1 PIC18F8XJ5X xxxx xxxx uuuu uuuu uuuu uuuu

LATB Feature1 PIC18F8XJ5X xxxx xxxx uuuu uuuu uuuu uuuu

LATA Feature1 PIC18F8XJ5X --xx xxxx --uu uuuu --uu uuuu

TABLE 4-2: INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)

Brown-out Reset

MCLR Resets

WDT Reset

RESET Instruction

Stack Resets

CM Resets

Wake-up via WDT

or Interrupt

Legend: u = unchanged, x = unknown, - = unimplemented bit, read as ‘0’, q = value depends on condition.

Shaded cells indicate conditions do not apply for the designated device.

Note 1: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are

updated with the current value of the PC. The STKPTR is modified to point to the next location in the

hardware stack.

2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the interrupt

vector (0008h or 0018h).

3: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).

4: See Table 4-1 for Reset value for specific condition.

PIC18F87J50 FAMILY

PORTJ Feature1 PIC18F8XJ5X xxxx xxxx uuuu uuuu uuuu uuuu

PORTH Feature1 PIC18F8XJ5X 0000 xxxx uuuu uuuu uuuu uuuu

PORTG Feature1 PIC18F8XJ5X 000x xxxx 000u uuuu uuuu uuuu

PORTF Feature1 PIC18F8XJ5X x00x x0-- u00u u0-- u00u u0--

PORTE Feature1 PIC18F8XJ5X xxxx xxxx uuuu uuuu uuuu uuuu

PORTD Feature1 PIC18F8XJ5X xxxx xxxx uuuu uuuu uuuu uuuu

PORTC Feature1 PIC18F8XJ5X xxxx xxxx uuuu uuuu uuuu uuuu

PORTB Feature1 PIC18F8XJ5X xxxx xxxx uuuu uuuu uuuu uuuu

PORTA Feature1 PIC18F8XJ5X --0x 0000 --0u 0000 --uu uuuu

SPBRGH1 Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

BAUDCON1 Feature1 PIC18F8XJ5X 0100 0-00 0100 0-00 uuuu u-uu

SPBRGH2 Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

BAUDCON2 Feature1 PIC18F8XJ5X 0100 0-00 0100 0-00 uuuu u-uu

TMR3H Feature1 PIC18F8XJ5X xxxx xxxx uuuu uuuu uuuu uuuu

TMR3L Feature1 PIC18F8XJ5X xxxx xxxx uuuu uuuu uuuu uuuu

T3CON Feature1 PIC18F8XJ5X 0000 0000 uuuu uuuu uuuu uuuu

TMR4 Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

PR4 Feature1 PIC18F8XJ5X 1111 1111 1111 1111 1111 1111

CVRCON Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

T4CON Feature1 PIC18F8XJ5X -000 0000 -000 0000 -uuu uuuu

CCPR4H Feature1 PIC18F8XJ5X xxxx xxxx uuuu uuuu uuuu uuuu

CCPR4L Feature1 PIC18F8XJ5X xxxx xxxx uuuu uuuu uuuu uuuu

CCP4CON Feature1 PIC18F8XJ5X --00 0000 --00 0000 --uu uuuu

CCPR5H Feature1 PIC18F8XJ5X xxxx xxxx uuuu uuuu uuuu uuuu

CCPR5L Feature1 PIC18F8XJ5X xxxx xxxx uuuu uuuu uuuu uuuu

CCP5CON Feature1 PIC18F8XJ5X --00 0000 --00 0000 --uu uuuu

SSP2BUF Feature1 PIC18F8XJ5X xxxx xxxx uuuu uuuu uuuu uuuu

SSP2ADD Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

SSP2MSK Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

SSP2STAT Feature1 PIC18F8XJ5X 1111 1111 1111 1111 uuuu uuuu

SSP2CON1 Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

SSP2CON2 Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

CMSTAT Feature1 PIC18F8XJ5X ---- --11 ---- --11 ---- --uu

TABLE 4-2: INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)

Brown-out Reset

MCLR Resets

WDT Reset

RESET Instruction

Stack Resets

CM Resets

Wake-up via WDT

or Interrupt

Legend: u = unchanged, x = unknown, - = unimplemented bit, read as ‘0’, q = value depends on condition.

Shaded cells indicate conditions do not apply for the designated device.

Note 1: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are

updated with the current value of the PC. The STKPTR is modified to point to the next location in the

hardware stack.

2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the interrupt

vector (0008h or 0018h).

3: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).

4: See Table 4-1 for Reset value for specific condition.

PIC18F87J50 FAMILY

PMADDRH Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

PMDOUT1H Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

PMADDRL Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

PMDOUT1L Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

PMDIN1H Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

PMDIN1L Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

UCON Feature1 PIC18F8XJ5X -0x0 000- -0x0 000- -uuu uuu-

USTAT Feature1 PIC18F8XJ5X -xxx xxx- -xxx xxx- -uuu uuu-

UEIR Feature1 PIC18F8XJ5X 0--0 0000 0--0 0000 u--u uuuu

UIR Feature1 PIC18F8XJ5X -000 0000 -000 0000 -uuu uuuu

UFRMH Feature1 PIC18F8XJ5X ---- -xxx ---- -xxx ---- -uuu

UFRML Feature1 PIC18F8XJ5X xxxx xxxx xxxx xxxx uuuu uuuu

UCFG Feature1 PIC18F8XJ5X 00-0 0000 00-0 0000 uu-u uuuu

UADDR Feature1 PIC18F8XJ5X -000 0000 -uuu uuuu -uuu uuuu

UEIE Feature1 PIC18F8XJ5X 0--0 0000 0--0 0000 u--u uuuu

UIE Feature1 PIC18F8XJ5X -000 0000 -000 0000 -uuu uuuu

UEP15 Feature1 PIC18F8XJ5X ---0 0000 ---0 0000 ---u uuuu

UEP14 Feature1 PIC18F8XJ5X ---0 0000 ---0 0000 ---u uuuu

UEP13 Feature1 PIC18F8XJ5X ---0 0000 ---0 0000 ---u uuuu

UEP12 Feature1 PIC18F8XJ5X ---0 0000 ---0 0000 ---u uuuu

UEP11 Feature1 PIC18F8XJ5X ---0 0000 ---0 0000 ---u uuuu

UEP10 Feature1 PIC18F8XJ5X ---0 0000 ---0 0000 ---u uuuu

UEP9 Feature1 PIC18F8XJ5X ---0 0000 ---0 0000 ---u uuuu

UEP8 Feature1 PIC18F8XJ5X ---0 0000 ---0 0000 ---u uuuu

UEP7 Feature1 PIC18F8XJ5X ---0 0000 ---0 0000 ---u uuuu

UEP6 Feature1 PIC18F8XJ5X ---0 0000 ---0 0000 ---u uuuu

UEP5 Feature1 PIC18F8XJ5X ---0 0000 ---0 0000 ---u uuuu

UEP4 Feature1 PIC18F8XJ5X ---0 0000 ---0 0000 ---u uuuu

UEP3 Feature1 PIC18F8XJ5X ---0 0000 ---0 0000 ---u uuuu

UEP2 Feature1 PIC18F8XJ5X ---0 0000 ---0 0000 ---u uuuu

UEP1 Feature1 PIC18F8XJ5X ---0 0000 ---0 0000 ---u uuuu

UEP0 Feature1 PIC18F8XJ5X ---0 0000 ---0 0000 ---u uuuu

PMCONH Feature1 PIC18F8XJ5X 0-00 0000 0-00 0000 u-uu uuuu

TABLE 4-2: INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)

Brown-out Reset

MCLR Resets

WDT Reset

RESET Instruction

Stack Resets

CM Resets

Wake-up via WDT

or Interrupt

Legend: u = unchanged, x = unknown, - = unimplemented bit, read as ‘0’, q = value depends on condition.

Shaded cells indicate conditions do not apply for the designated device.

Note 1: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are

updated with the current value of the PC. The STKPTR is modified to point to the next location in the

hardware stack.

2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the interrupt

vector (0008h or 0018h).

3: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).

4: See Table 4-1 for Reset value for specific condition.

PIC18F87J50 FAMILY

PMCONL Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

PMMODEH Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

PMMODEL Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

PMDOUT2H Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

PMDOUT2L Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

PMDIN2H Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

PMDIN2L Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

PMEH Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

PMEL Feature1 PIC18F8XJ5X 0000 0000 0000 0000 uuuu uuuu

PMSTATH Feature1 PIC18F8XJ5X 00-- 0000 00-- 0000 uu-- uuuu

PMSTATL Feature1 PIC18F8XJ5X 10-- 1111 10-- 1111 uu-- uuuu

TABLE 4-2: INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)

Brown-out Reset

MCLR Resets

WDT Reset

RESET Instruction

Stack Resets

CM Resets

Wake-up via WDT

or Interrupt

Legend: u = unchanged, x = unknown, - = unimplemented bit, read as ‘0’, q = value depends on condition.

Shaded cells indicate conditions do not apply for the designated device.

Note 1: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are

updated with the current value of the PC. The STKPTR is modified to point to the next location in the

hardware stack.

2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the interrupt

vector (0008h or 0018h).

3: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).

4: See Table 4-1 for Reset value for specific condition.

PIC18F87J50 FAMILY

NOTES:

PIC18F87J50 FAMILY

5.0 MEMORY ORGANIZATION

There are two types of memory in PIC18 Flash

microcontroller devices:

• Program Memory

• Data RAM

As Harvard architecture devices, the data and program

memories use separate busses; this allows for

concurrent access of the two memory spaces.

Additional detailed information on the operation of the

Flash program memory is provided in Section 6.0

“Flash Program Memory”.

5.1 Program Memory Organization

PIC18 microcontrollers implement a 21-bit program

counter which is capable of addressing a 2-Mbyte

program memory space. Accessing a location between

the upper boundary of the physically implemented

memory and the 2-Mbyte address will return all ‘0’s (a

NOP instruction).

The entire PIC18F87J10 family offers a range of

on-chip Flash program memory sizes, from 64 Kbytes

(up to 16,384 single-word instructions) to 128 Kbytes

(65,536 single-word instructions). The program

memory maps for individual family members are shown

in Figure 5-3.

FIGURE 5-1: MEMORY MAPS FOR PIC18F87J50 FAMILY DEVICES

Note: Sizes of memory areas are not to scale. Sizes of program memory areas are enhanced to show detail.

Unimplemented

Read as ‘0’

Unimplemented

Read as ‘0’

Unimplemented

Read as ‘0’

000000h

1FFFFFF

PIC18FX5J50 PIC18FX6J50 PIC18FX6J55 PIC18FX7J50

007FFFh

00FFFFh

017FFFh

PC<20:0>

Stack Level 1

•

Stack Level 31

•

CALL, CALLW, RCALL,

RETURN, RETFIE, RETLW,

User Memory Space

On-Chip

Memory

On-Chip

Memory

On-Chip

Memory

On-Chip

Memory

ADDULNK, SUBULNK

Config. Words

Config. Words 01FFFFh

Unimplemented

Read as ‘0’

PIC18F87J50 FAMILY

5.1.1 HARD MEMORY VECTORS

All PIC18 devices have a total of three hard-coded

return vectors in their program memory space. The

Reset vector address is the default value to which the

program counter returns on all device Resets; it is

located at 0000h.

PIC18 devices also have two interrupt vector

addresses for the handling of high-priority and

low-priority interrupts. The high-priority interrupt vector

is located at 0008h and the low-priority interrupt vector

is at 0018h. Their locations in relation to the program

memory map are shown in Figure 5-2.

FIGURE 5-2: HARD VECTOR AND

CONFIGURATION WORD

LOCATIONS FOR

PIC18F87J50 FAMILY

DEVICES

5.1.2 FLASH CONFIGURATION WORDS

Because PIC18F87J10 family devices do not have per-

sistent configuration memory, the top four words of

on-chip program memory are reserved for configuration

information. On Reset, the configuration information is

copied into the Configuration registers.

The Configuration Words are stored in their program

memory location in numerical order, starting with the

lower byte of CONFIG1 at the lowest address and end-

ing with the upper byte of CONFIG4. For these devices,

only Configuration Words, CONFIG1 through

CONFIG3, are used; CONFIG4 is reserved. The actual

addresses of the Flash Configuration Word for devices

in the PIC18F87J10 family are shown in Table 5-1.

Their location in the memory map is shown with the

other memory vectors in Figure 5-2.

Additional details on the device Configuration Words

are provided in Section 25.1 “Configuration Bits”.

TABLE 5-1: FLASH CONFIGURATION

WORD FOR PIC18F87J50

FAMILY DEVICES

Reset Vector

Low-Priority Interrupt Vector

0000h

0018h

On-Chip

Program Memory

High-Priority Interrupt Vector 0008h

1FFFFFh

(Top of Memory)

(Top of Memory-7)

Flash Configuration Words

Read as ‘0’

Legend: (Top of Memory) represents upper boundary

of on-chip program memory space (see

Figure 5-1 for device-specific values).

Shaded area represents unimplemented

memory. Areas are not shown to scale.

Device

Program

Memory

(Kbytes)

Configuration

Word

Addresses

PIC18F65J50 32 7FF8h to 7FFFh

PIC18F85J50

PIC18F66J50 64 FFF8h to FFFFh

PIC18F86J50

PIC18F66J55 96 17FF8h to

17FFFh

PIC18F86J55

PIC18F67J50 128 1FFF8h to

1FFFFh

PIC18F87J50

PIC18F87J50 FAMILY

5.1.3 PIC18F87J50 FAMILY PROGRAM

MEMORY MODES

The 80-pin devices in this family can address up to a

total of 2 Mbytes of program memory. This is achieved

through the External Memory Bus. There are two

distinct operating modes available to the controllers:

• Microcontroller (MC)

• Extended Microcontroller (EMC)

The program memory mode is determined by setting

the EMB Configuration bits (CONFIG3L<5:4>), as

shown in Register 5-1. (See also Section 25.1

“Configuration Bits” for additional details on the

device Configuration bits.)

The program memory modes operate as follows:

•The Microcontroller Mode accesses only on-chip

Flash memory. Attempts to read above the top of

on-chip memory causes a read of all ‘0’s (a NOP

instruction).

The Microcontroller mode is also the only operating

mode available to 64-pin devices.

•The Extended Microcontroller Mode allows

access to both internal and external program

memories as a single block. The device can

access its entire on-chip program memory; above

this, the device accesses external program

memory up to the 2-Mbyte program space limit.

Execution automatically switches between the

two memories as required.

The setting of the EMB Configuration bits also controls

the address bus width of the External Memory Bus.

This is covered in more detail in Section 7.0 “External

Memory Bus”.

In all modes, the microcontroller has complete access

to data RAM.

Figure 5-3 compares the memory maps of the different

program memory modes. The differences between

on-chip and external memory access limitations are

more fully explained in Table 5-2.

R/WO-1 R/WO-1 R/WO-1 R/WO-1 R/WO-1 U-0 U-0 U-0

WAIT(1) BW(1) EMB1(1) EMB0(1) EASHFT(1) — — —

bit 7 bit 0

Legend:

R = Readable bit WO = Write-Once bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 WAIT: External Bus Wait Enable bit(1)

1 = Wait states on the external bus are disabled

0 = Wait states on the external bus are enabled and selected by MEMCON<5:4>

bit 6 BW: Data Bus Width Select bit(1)

1 = 16-Bit Data Width modes

0 = 8-Bit Data Width modes

bit 5-4 EMB1:EMB0: External Memory Bus Configuration bits(1)

11 = Microcontroller mode, external bus disabled

10 = Extended Microcontroller mode, 12-bit address width for external bus

01 = Extended Microcontroller mode, 16-bit address width for external bus

00 = Extended Microcontroller mode, 20-bit address width for external bus

bit 3 EASHFT: External Address Bus Shift Enable bit(1)

1 = Address shifting enabled – external address bus is shifted to start at 000000h

0 = Address shifting disabled – external address bus reflects the PC value

bit 2-0 Unimplemented: Read as ‘0’

Note 1: Implemented only on 80-pin devices.

PIC18F87J50 FAMILY

5.1.4 EXTENDED MICROCONTROLLER

MODE AND ADDRESS SHIFTING

By default, devices in Extended Microcontroller mode

directly present the program counter value on the

external address bus for those addresses in the range

of the external memory space. In practical terms, this

means addresses in the external memory device below

the top of on-chip memory are unavailable.

To avoid this, the Extended Microcontroller mode

implements an address shifting option to enable auto-

matic address translation. In this mode, addresses

presented on the external bus are shifted down by the

size of the on-chip program memory and are remapped

to start at 0000h. This allows the complete use of the

external memory device’s memory space.

FIGURE 5-3: MEMORY MAPS FOR PIC18F87J50 FAMILY PROGRAM MEMORY MODES

TABLE 5-2: MEMORY ACCESS FOR PIC18F8XJ5X PROGRAM MEMORY MODES

External

Memory

On-Chip

Program

Memory

Microcontroller Mode(1)

000000h

On-Chip

Program

Memory

1FFFFFh

Reads

‘0’s

External On-Chip

Memory Memory

(Top of Memory)

(Top of Memory) + 1

Legend: (Top of Memory) represents upper boundary of on-chip program memory space (see Figure 5-1 for device-specific

values). Shaded areas represent unimplemented, or inaccessible areas, depending on the mode.

Note 1: This mode is the only available mode on 64-pin devices and the default on 80-pin devices.

2: These modes are only available on 80-pin devices.

3: Addresses starting at the top of the program memory are translated to start at 0000h of the external device

whenever the EASHFT Configuration bit is set.

Extended Microcontroller Mode(2)

000000h

1FFFFFh

(Top of Memory)

(Top of Memory) + 1 External

Memory

On-Chip

Program

Memory

000000h

1FFFFFh

(Top of Memory)

(Top of Memory) + 1(3)

Access

Space

On-Chip

Memory

Space

External On-Chip

Memory Memory

Space

Mapped

External

Memory

Space

Space Space

Mapped

External

Memory

Space (Top of Memory)

Extended Microcontroller Mode

with Address Shifting(2)

1FFFFFh –

Operating Mode

Internal Program Memory External Program Memory

Execution

From

Table Read

From

Table Write

Execution

From

Table Read

From

Table Write

Microcontroller Yes Yes Yes No Access No Access No Access

Extended Microcontroller Yes Yes Yes Yes Yes Yes

PIC18F87J50 FAMILY

5.1.5 PROGRAM COUNTER

The Program Counter (PC) specifies the address of the

instruction to fetch for execution. The PC is 21 bits wide

and is contained in three separate 8-bit registers. The

low byte, known as the PCL register, is both readable

and writable. The high byte, or PCH register, contains

the PC<15:8> bits; it is not directly readable or writable.

Updates to the PCH register are performed through the

PCLATH register. The upper byte is called PCU. This

directly readable or writable. Updates to the PCU

The contents of PCLATH and PCLATU are transferred

to the program counter by any operation that writes

PCL. Similarly, the upper two bytes of the program

counter are transferred to PCLATH and PCLATU by an

operation that reads PCL. This is useful for computed

offsets to the PC (see Section 5.1.8.1 “Computed

GOTO”).

The PC addresses bytes in the program memory. To

prevent the PC from becoming misaligned with word

instructions, the Least Significant bit of PCL is fixed to

a value of ‘0’. The PC increments by 2 to address

sequential instructions in the program memory.

The CALL, RCALL, GOTO and program branch

instructions write to the program counter directly. For

these instructions, the contents of PCLATH and

PCLATU are not transferred to the program counter.

5.1.6 RETURN ADDRESS STACK

The return address stack allows any combination of up

to 31 program calls and interrupts to occur. The PC is

pushed onto the stack when a CALL or RCALL instruc-

tion is executed, or an interrupt is Acknowledged. The

PC value is pulled off the stack on a RETURN, RETLW

or a RETFIE instruction (and on ADDULNK and

SUBULNK instructions if the extended instruction set is

enabled). PCLATU and PCLATH are not affected by

any of the RETURN or CALL instructions.

The stack operates as a 31-word by 21-bit RAM and a

5-bit Stack Pointer, STKPTR. The stack space is not

part of either program or data space. The Stack Pointer

is readable and writable and the address on the top of

the stack is readable and writable through the

Top-of-Stack Special Function Registers. Data can also

be pushed to, or popped from the stack, using these

registers.

A CALL type instruction causes a push onto the stack.

The Stack Pointer is first incremented and the location

pointed to by the Stack Pointer is written with the

contents of the PC (already pointing to the instruction

following the CALL). A RETURN type instruction causes

a pop from the stack. The contents of the location

pointed to by the STKPTR are transferred to the PC

and then the Stack Pointer is decremented.

The Stack Pointer is initialized to ‘00000’ after all

Resets. There is no RAM associated with the location

corresponding to a Stack Pointer value of ‘00000’; this

is only a Reset value. Status bits indicate if the stack is

full, has overflowed or has underflowed.

5.1.6.1 Top-of-Stack Access

Only the top of the return address stack (TOS) is read-

able and writable. A set of three registers,

TOSU:TOSH:TOSL, hold the contents of the stack

location pointed to by the STKPTR register

(Figure 5-4). This allows users to implement a software

stack if necessary. After a CALL, RCALL or interrupt

(and ADDULNK and SUBULNK instructions if the

extended instruction set is enabled), the software can

read the pushed value by reading the

TOSU:TOSH:TOSL registers. These values can be

placed on a user-defined software stack. At return time,

the software can return these values to

TOSU:TOSH:TOSL and do a return.

The user must disable the global interrupt enable bits

while accessing the stack to prevent inadvertent stack

corruption.

FIGURE 5-4: RETURN ADDRESS STACK AND ASSOCIATED REGISTERS

00011

001A34h

11111

11110

11101

00010

00001

00000

00010

Return Address Stack <20:0>

To p - o f - St ac k

000D58h

TOSLTOSHTOSU

34h1Ah00h

STKPTR<4:0>

Top-of-Stack Registers Stack Pointer

PIC18F87J50 FAMILY

5.1.6.2 Return Stack Pointer (STKPTR)

The STKPTR register (Register 5-2) contains the Stack

Pointer value, the STKFUL (Stack Full) status bit and

the STKUNF (Stack Underflow) status bits. The value

of the Stack Pointer can be 0 through 31. The Stack

Pointer increments before values are pushed onto the

stack and decrements after values are popped off the

stack. On Reset, the Stack Pointer value will be zero.

The user may read and write the Stack Pointer value.

This feature can be used by a Real-Time Operating

System (RTOS) for return stack maintenance.

After the PC is pushed onto the stack 31 times (without

popping any values off the stack), the STKFUL bit is

set. The STKFUL bit is cleared by software or by a

POR.

The action that takes place when the stack becomes

full depends on the state of the STVREN (Stack Over-

flow Reset Enable) Configuration bit. (Refer to

Section 25.1 “Configuration Bits” for a description of

the device Configuration bits.) If STVREN is set

(default), the 31st push will push the (PC + 2) value

onto the stack, set the STKFUL bit and reset the

device. The STKFUL bit will remain set and the Stack

Pointer will be set to zero.

If STVREN is cleared, the STKFUL bit will be set on the

31st push and the Stack Pointer will increment to 31.

Any additional pushes will not overwrite the 31st push

and the STKPTR will remain at 31.

When the stack has been popped enough times to

unload the stack, the next pop will return a value of zero

to the PC and set the STKUNF bit, while the Stack

Pointer remains at zero. The STKUNF bit will remain

set until cleared by software or until a POR occurs.

5.1.6.3 PUSH and POP Instructions

Since the Top-of-Stack is readable and writable, the

ability to push values onto the stack and pull values off

the stack, without disturbing normal program execu-

tion, is a desirable feature. The PIC18 instruction set

includes two instructions, PUSH and POP, that permit

the TOS to be manipulated under software control.

TOSU, TOSH and TOSL can be modified to place data

or a return address on the stack.

The PUSH instruction places the current PC value onto

the stack. This increments the Stack Pointer and loads

the current PC value onto the stack.

The POP instruction discards the current TOS by

decrementing the Stack Pointer. The previous value

pushed onto the stack then becomes the TOS value.

Note: Returning a value of zero to the PC on an

underflow has the effect of vectoring the

program to the Reset vector, where the

stack conditions can be verified and

appropriate actions can be taken. This is

not the same as a Reset, as the contents

of the SFRs are not affected.

R/C-0 R/C-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

STKFUL(1) STKUNF(1) — SP4 SP3 SP2 SP1 SP0

bit 7 bit 0

Legend: C = Clearable only bit

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 STKFUL: Stack Full Flag bit(1)

1 = Stack became full or overflowed

0 = Stack has not become full or overflowed

bit 6 STKUNF: Stack Underflow Flag bit(1)

1 = Stack underflow occurred

0 = Stack underflow did not occur

bit 5 Unimplemented: Read as ‘0’

bit 4-0 SP4:SP0: Stack Pointer Location bits

Note 1: Bit 7 and bit 6 are cleared by user software or by a POR.

PIC18F87J50 FAMILY

5.1.6.4 Stack Full and Underflow Resets

Device Resets on stack overflow and stack underflow

conditions are enabled by setting the STVREN bit in

Configuration Register 1L. When STVREN is set, a full

or underflow condition will set the appropriate STKFUL

or STKUNF bit and then cause a device Reset. When

STVREN is cleared, a full or underflow condition will set

the appropriate STKFUL or STKUNF bit, but not cause

a device Reset. The STKFUL or STKUNF bits are

cleared by the user software or a Power-on Reset.

5.1.7 FAST REGISTER STACK

A Fast Register Stack is provided for the STATUS,

WREG and BSR registers to provide a “fast return”

option for interrupts. This stack is only one level deep

and is neither readable nor writable. It is loaded with the

current value of the corresponding register when the

processor vectors for an interrupt. All interrupt sources

will push values into the Stack registers. The values in

the registers are then loaded back into the working

registers if the RETFIE, FAST instruction is used to

return from the interrupt.

If both low and high-priority interrupts are enabled, the

Stack registers cannot be used reliably to return from

low-priority interrupts. If a high-priority interrupt occurs

while servicing a low-priority interrupt, the Stack

be overwritten. In these cases, users must save the key

registers in software during a low-priority interrupt.

If interrupt priority is not used, all interrupts may use the

Fast Register Stack for returns from interrupt. If no

interrupts are used, the Fast Register Stack can be

used to restore the STATUS, WREG and BSR registers

at the end of a subroutine call. To use the Fast Register

Stack for a subroutine call, a CALL label, FAST

instruction must be executed to save the STATUS,

WREG and BSR registers to the Fast Register Stack. A

RETURN, FAST instruction is then executed to restore

these registers from the Fast Register Stack.

Example 5-1 shows a source code example that uses

the Fast Register Stack during a subroutine call and

return.

EXAMPLE 5-1: FAST REGISTER STACK

CODE EXAMPLE

5.1.8 LOOK-UP TABLES IN PROGRAM

MEMORY

There may be programming situations that require the

creation of data structures, or look-up tables, in

program memory. For PIC18 devices, look-up tables

can be implemented in two ways:

• Computed GOTO

• Table Reads

5.1.8.1 Computed GOTO

A computed GOTO is accomplished by adding an offset

to the program counter. An example is shown in

Example 5-2.

A look-up table can be formed with an ADDWF PCL

instruction and a group of RETLW nn instructions. The

W register is loaded with an offset into the table before

executing a call to that table. The first instruction of the

called routine is the ADDWF PCL instruction. The next

instruction executed will be one of the RETLW nn

instructions that returns the value ‘nn’ to the calling

function.

The offset value (in WREG) specifies the number of

bytes that the program counter should advance and

should be multiples of 2 (LSb = 0).

In this method, only one data byte may be stored in

each instruction location and room on the return

address stack is required.

EXAMPLE 5-2: COMPUTED GOTO USING

AN OFFSET VALUE

5.1.8.2 Table Reads

A better method of storing data in program memory

allows two bytes of data to be stored in each instruction

location.

Look-up table data may be stored two bytes per

program word while programming. The Table Pointer

(TBLPTR) specifies the byte address and the Table

Latch (TABLAT) contains the data that is read from the

program memory. Data is transferred from program

memory one byte at a time.

Table read operation is discussed further in

Section 6.1 “Table Reads and Table Writes”.

CALL SUB1, FAST ;STATUS, WREG, BSR

;SAVED IN FAST REGISTER

;STACK

•

SUB1 •

•

RETURN FAST ;RESTORE VALUES SAVED

;IN FAST REGISTER STACK

MOVF OFFSET, W

CALL TABLE

ORG nn00h

TABLE ADDWF PCL

RETLW nnh

PIC18F87J50 FAMILY

5.2 PIC18 Instruction Cycle

5.2.1 CLOCKING SCHEME

The microcontroller clock input, whether from an

internal or external source, is internally divided by four

to generate four non-overlapping quadrature clocks

(Q1, Q2, Q3 and Q4). Internally, the program counter is

incremented on every Q1; the instruction is fetched

from the program memory and latched into the Instruc-

tion Register (IR) during Q4. The instruction is decoded

and executed during the following Q1 through Q4. The

clocks and instruction execution flow are shown in

Figure 5-5.

5.2.2 INSTRUCTION FLOW/PIPELINING

An “Instruction Cycle” consists of four Q cycles, Q1

through Q4. The instruction fetch and execute are pipe-

lined in such a manner that a fetch takes one instruction

cycle, while the decode and execute takes another

instruction cycle. However, due to the pipelining, each

instruction effectively executes in one cycle. If an

instruction causes the program counter to change (e.g.,

GOTO), then two cycles are required to complete the

instruction (Example 5-3).

A fetch cycle begins with the Program Counter (PC)

incrementing in Q1.

In the execution cycle, the fetched instruction is latched

into the Instruction Register (IR) in cycle Q1. This

instruction is then decoded and executed during the

Q2, Q3 and Q4 cycles. Data memory is read during Q2

(operand read) and written during Q4 (destination

write).

FIGURE 5-5: CLOCK/INSTRUCTION CYCLE

EXAMPLE 5-3: INSTRUCTION PIPELINE FLOW

Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4

OSC1

OSC2/CLKO

(RC mode)

PC PC + 2 PC + 4

Fetch INST (PC)

Execute INST (PC – 2)

Fetch INST (PC + 2)

Execute INST (PC)

Fetch INST (PC + 4)

Execute INST (PC + 2)

Internal

Phase

Clock

All instructions are single cycle, except for any program branches. These take two cycles since the fetch instruction

is “flushed” from the pipeline while the new instruction is being fetched and then executed.

TCY0TCY1TCY2TCY3TCY4TCY5

1. MOVLW 55h Fetch 1 Execute 1

2. MOVWF PORTB Fetch 2 Execute 2

3. BRA SUB_1 Fetch 3 Execute 3

4. BSF PORTA, BIT3 (Forced NOP) Fetch 4 Flush (NOP)

5. Instruction @ address SUB_1 Fetch SUB_1 Execute SUB_1

PIC18F87J50 FAMILY

5.2.3 INSTRUCTIONS IN PROGRAM

MEMORY

The program memory is addressed in bytes. Instruc-

tions are stored as two bytes or four bytes in program

memory. The Least Significant Byte of an instruction

word is always stored in a program memory location

with an even address (LSB = 0). To maintain alignment

with instruction boundaries, the PC increments in steps

of 2 and the LSB will always read ‘0’ (see Section 5.1.5

“Program Counter”).

Figure 5-6 shows an example of how instruction words

are stored in the program memory.

The CALL and GOTO instructions have the absolute

program memory address embedded into the instruc-

tion. Since instructions are always stored on word

boundaries, the data contained in the instruction is a

word address. The word address is written to PC<20:1>

which accesses the desired byte address in program

memory. Instruction #2 in Figure 5-6 shows how the

instruction, GOTO 0006h, is encoded in the program

memory. Program branch instructions, which encode a

relative address offset, operate in the same manner. The

offset value stored in a branch instruction represents the

number of single-word instructions that the PC will be

offset by. Section 26.0 “Instruction Set Summary”

provides further details of the instruction set.

FIGURE 5-6: INSTRUCTIONS IN PROGRAM MEMORY

5.2.4 TWO-WORD INSTRUCTIONS

The standard PIC18 instruction set has four two-word

instructions: CALL, MOVFF, GOTO and LSFR. In all

cases, the second word of the instructions always has

‘1111’ as its four Most Significant bits; the other 12 bits

are literal data, usually a data memory address.

The use of ‘1111’ in the 4 MSbs of an instruction

specifies a special form of NOP. If the instruction is

executed in proper sequence – immediately after the

first word – the data in the second word is accessed

and used by the instruction sequence. If the first word

is skipped for some reason and the second word is

executed by itself, a NOP is executed instead. This is

necessary for cases when the two-word instruction is

preceded by a conditional instruction that changes the

PC. Example 5-4 shows how this works.

EXAMPLE 5-4: TWO-WORD INSTRUCTIONS

Word Address

LSB = 1LSB = 0↓

Program Memory

Byte Locations →

000000h

000002h

000004h

000006h

Instruction 1: MOVLW 055h 0Fh 55h 000008h

Instruction 2: GOTO 0006h EFh 03h 00000Ah

F0h 00h 00000Ch

Instruction 3: MOVFF 123h, 456h C1h 23h 00000Eh

F4h 56h 000010h

000012h

000014h

Note: See Section 5.5 “Program Memory and

the Extended Instruction Set” for

information on two-word instructions in the

extended instruction set.

CASE 1:

Object Code Source Code

0110 0110 0000 0000 TSTFSZ REG1 ; is RAM location 0?

1100 0001 0010 0011 MOVFF REG1, REG2 ; No, skip this word

1111 0100 0101 0110 ; Execute this word as a NOP

0010 0100 0000 0000 ADDWF REG3 ; continue code

CASE 2:

Object Code Source Code

0110 0110 0000 0000 TSTFSZ REG1 ; is RAM location 0?

1100 0001 0010 0011 MOVFF REG1, REG2 ; Yes, execute this word

1111 0100 0101 0110 ; 2nd word of instruction

0010 0100 0000 0000 ADDWF REG3 ; continue code

PIC18F87J50 FAMILY

5.3 Data Memory Organization

The data memory in PIC18 devices is implemented as

static RAM. Each register in the data memory has a

12-bit address, allowing up to 4096 bytes of data

memory. The memory space is divided into as many as

16 banks that contain 256 bytes each. The

PIC18F87J10 family implements all available banks

and provides 3904 bytes of data memory available to

the user. Figure 5-7 shows the data memory

organization for the devices.

The data memory contains Special Function Registers

(SFRs) and General Purpose Registers (GPRs). The

SFRs are used for control and status of the controller

and peripheral functions, while GPRs are used for data

storage and scratchpad operations in the user’s

application. Any read of an unimplemented location will

read as ‘0’s.

The instruction set and architecture allow operations

across all banks. The entire data memory may be

accessed by Direct, Indirect or Indexed Addressing

modes. Addressing modes are discussed later in this

section.

To ensure that commonly used registers (select SFRs

and select GPRs) can be accessed in a single cycle,

PIC18 devices implement an Access Bank. This is a

256-byte memory space that provides fast access to

select SFRs and the lower portion of GPR Bank 0 with-

out using the BSR. Section 5.3.3 “Access Bank”

provides a detailed description of the Access RAM.

5.3.1 USB RAM

The entire data memory is actually mapped to a special

dual access RAM. When the USB module is disabled,

the GPRs in these banks are used like any other GPR

in the data memory space.

When the USB module is enabled, the memory in these

banks is allocated as buffer RAM for USB operation.

This area is shared between the microcontroller core

and the USB Serial Interface Engine (SIE) and is used

to transfer data directly between the two.

It is theoretically possible to use the areas of USB RAM

that are not allocated as USB buffers for normal

scratchpad memory or other variable storage. In

practice, the dynamic nature of buffer allocation makes

this risky at best. Additionally, Bank 4 is used for USB

buffer management when the module is enabled and

should not be used for any other purposes during that

time. Additional information on USB RAM and buffer

operation is provided in Section 22.0 “Universal

Serial Bus (USB)”

5.3.2 BANK SELECT REGISTER

Large areas of data memory require an efficient

addressing scheme to make rapid access to any

address possible. Ideally, this means that an entire

address does not need to be provided for each read or

write operation. For PIC18 devices, this is accom-

plished with a RAM banking scheme. This divides the

memory space into 16 contiguous banks of 256 bytes.

Depending on the instruction, each location can be

addressed directly by its full 12-bit address, or an 8-bit

low-order address and a 4-bit Bank Pointer.

Most instructions in the PIC18 instruction set make use

of the Bank Pointer, known as the Bank Select Register

(BSR). This SFR holds the 4 Most Significant bits of a

location’s address; the instruction itself includes the

8 Least Significant bits. Only the four lower bits of the

BSR are implemented (BSR3:BSR0). The upper four

bits are unused; they will always read ‘0’ and cannot be

written to. The BSR can be loaded directly by using the

MOVLB instruction.

The value of the BSR indicates the bank in data mem-

ory. The 8 bits in the instruction show the location in the

bank and can be thought of as an offset from the bank’s

lower boundary. The relationship between the BSR’s

value and the bank division in data memory is shown in

Figure 5-8.

Since up to 16 registers may share the same low-order

address, the user must always be careful to ensure that

the proper bank is selected before performing a data

read or write. For example, writing what should be

program data to an 8-bit address of F9h while the BSR

is 0Fh, will end up resetting the program counter.

While any bank can be selected, only those banks that

are actually implemented can be read or written to.

Writes to unimplemented banks are ignored, while

reads from unimplemented banks will return ‘0’s. Even

so, the STATUS register will still be affected as if the

operation was successful. The data memory map in

Figure 5-7 indicates which banks are implemented.

In the core PIC18 instruction set, only the MOVFF

instruction fully specifies the 12-bit address of the

source and target registers. This instruction ignores the

BSR completely when it executes. All other instructions

include only the low-order address as an operand and

must use either the BSR or the Access Bank to locate

their target registers.

Note: The operation of some aspects of data

memory are changed when the PIC18

extended instruction set is enabled. See

Section 5.6 “Data Memory and the

Extended Instruction Set” for more

information.

PIC18F87J50 FAMILY

FIGURE 5-7: DATA MEMORY MAP FOR PIC18F87J50 FAMILY DEVICES

Bank 0

Bank 1

Bank 14

Bank 15

Data Memory Map

BSR<3:0>

= 0000

= 0001

= 1111

060h

05Fh

F5Fh

FFFh

00h

5Fh

60h

FFh

Access Bank

When a = 0:

The BSR is ignored and the

Access Bank is used.

The first 96 bytes are general

purpose RAM (from Bank 0).

The remaining 160 bytes are

Special Function Registers

(from Bank 15).

When a = 1:

The BSR specifies the bank

used by the instruction.

F3Fh

F00h

EFFh

1FFh

100h

0FFh

000h

Access RAM

FFh

00h

FFh

00h

FFh

00h

GPR(1)

SFR(2)

Access RAM High

Access RAM Low

Bank 2

= 0010

(SFRs)

2FFh

200h

Bank 3

FFh

00h

GPR(1)

FFh

= 0011

= 1101

GPR(1)

GPR, BDT(1)

GPR(1)

4FFh

400h

5FFh

500h

3FFh

300h

FFh

00h

FFh

00h

FFh

00h

FFh

00h

FFh

00h

FFh

00h

FFh

00h

FFh

00h

FFh

00h

FFh

00h

FFh

00h

GPR(1)

= 0110

= 0111

= 1010

= 1100

= 1000

= 0101

= 1001

= 1011

= 0100 Bank 4

Bank 5

Bank 6

Bank 7

Bank 8

Bank 9

Bank 10

Bank 11

Bank 12

Bank 13

= 1110

6FFh

600h

7FFh

700h

8FFh

800h

9FFh

900h

AFFh

A00h

BFFh

B00h

CFFh

C00h

DFFh

D00h

E00h

Note 1: These banks also serve as RAM buffers for USB operation. See Section 5.3.1 “USB RAM” for more information.

2: Addresses, F40h through F5Fh, are not part of the Access Bank, therefore, specifying a BSR should be used to

access these registers.

40h

60h

Access RAM

PIC18F87J50 FAMILY

FIGURE 5-8: USE OF THE BANK SELECT REGISTER (DIRECT ADDRESSING)

5.3.3 ACCESS BANK

While the use of the BSR with an embedded 8-bit

address allows users to address the entire range of

data memory, it also means that the user must always

ensure that the correct bank is selected. Otherwise,

data may be read from or written to the wrong location.

This can be disastrous if a GPR is the intended target

of an operation, but an SFR is written to instead.

Verifying and/or changing the BSR for each read or

write to data memory can become very inefficient.

To streamline access for the most commonly used data

memory locations, the data memory is configured with

an Access Bank, which allows users to access a

mapped block of memory without specifying a BSR.

The Access Bank consists of the first 96 bytes of

memory (00h-5Fh) in Bank 0 and the last 160 bytes of

memory (60h-FFh) in Bank 15. The lower half is known

as the “Access RAM” and is composed of GPRs. The

upper half is where the device’s SFRs are mapped.

These two areas are mapped contiguously in the

Access Bank and can be addressed in a linear fashion

by an 8-bit address (Figure 5-7).

The Access Bank is used by core PIC18 instructions

that include the Access RAM bit (the ‘a’ parameter in

the instruction). When ‘a’ is equal to ‘1’, the instruction

uses the BSR and the 8-bit address included in the

opcode for the data memory address. When ‘a’ is ‘0’,

however, the instruction is forced to use the Access

Bank address map; the current value of the BSR is

ignored entirely.

Using this “forced” addressing allows the instruction to

operate on a data address in a single cycle without

updating the BSR first. For 8-bit addresses of 60h and

above, this means that users can evaluate and operate

on SFRs more efficiently. The Access RAM below 60h

is a good place for data values that the user might need

to access rapidly, such as immediate computational

results or common program variables. Access RAM

also allows for faster and more code efficient context

saving and switching of variables.

The mapping of the Access Bank is slightly different

when the extended instruction set is enabled (XINST

Configuration bit = 1). This is discussed in more detail

in Section 5.6.3 “Mapping the Access Bank in

Indexed Literal Offset Mode”.

5.3.4 GENERAL PURPOSE

PIC18 devices may have banked memory in the GPR

area. This is data RAM which is available for use by all

instructions. GPRs start at the bottom of Bank 0

(address 000h) and grow upwards towards the bottom

of the SFR area. GPRs are not initialized by a

Power-on Reset and are unchanged on all other

Resets.

Note 1: The Access RAM bit of the instruction can be used to force an override of the selected bank (BSR<3:0>) to

the registers of the Access Bank.

2: The MOVFF instruction embeds the entire 12-bit address in the instruction.

Data Memory

Bank Select(2)

From Opcode(2)

0000

000h

100h

200h

300h

F00h

E00h

FFFh

Bank 0

Bank 1

Bank 2

Bank 14

Bank 15

00h

FFh

00h

FFh

00h

FFh

00h

FFh

00h

FFh

00h

FFh

Bank 3

through

Bank 13

0010 11111 111

BSR(1)

11111111

PIC18F87J50 FAMILY

5.3.5 SPECIAL FUNCTION REGISTERS

The Special Function Registers (SFRs) are registers

used by the CPU and peripheral modules for controlling

the desired operation of the device. These registers are

implemented as static RAM. SFRs start at the top of

data memory (FFFh) and extend downward to occupy

more than the top half of Bank 15 (F40h to FFFh). A list

of these registers is given inTable 5-3, Table 5-4 and

Table 5-5.

The SFRs can be classified into two sets: those

associated with the “core” device functionality (ALU,

Resets and interrupts) and those related to the

peripheral functions. The Reset and interrupt registers

are described in their respective chapters, while the

ALU’s STATUS register is described later in this

section. Registers related to the operation of the

peripheral features are described in the chapter for that

peripheral.

The SFRs are typically distributed among the

peripherals whose functions they control. Unused SFR

locations are unimplemented and read as ‘0’s

Note: Addresses, F40h through F5Fh, are not

part of the Access Bank, therefore specify-

ing a BSR should be used to access these

registers.

TABLE 5-3: SPECIAL FUNCTION REGISTER MAP FOR PIC18F87J50 FAMILY DEVICES

Address Name Address Name Address Name Address Name Address Name Address Name

FFFh TOSU FDFh INDF2

(1)

FBFh ECCP1AS F9Fh IPR1 F7Fh SPBRGH1 F5Fh UCFG

FFEh TOSH FDEh POSTINC2

(1)

FBEh ECCP1DEL F9Eh PIR1 F7Eh BAUDCON1 F5Eh UADDR

FFDh TOSL FDDh POSTDEC2

(1)

FBDh CCPR1H F9Dh PIE1 F7Dh SPBRGH2 F5Dh UEIE

FFCh STKPTR FDCh PREINC2

(1)

FBCh CCPR1L F9Ch RCSTA2 F7Ch BAUDCON2 F5Ch UIE

FFBh PCLATU FDBh PLUSW2

(1)

FBBh CCP1CON F9Bh OSCTUNE F7Bh TMR3H F5Bh UEP15

FFAh PCLATH FDAh FSR2H FBAh ECCP2AS F9Ah TRISJ

(2)

F7Ah TMR3L F5Ah UEP14

FF9h PCL FD9h FSR2L FB9h ECCP2DEL F99h TRISH

(2)

F79h T3CON F59h UEP13

FF8h TBLPTRU FD8h STATUS FB8h CCPR2H F98h TRISG F78h TMR4 F58h UEP12

FF7h TBLPTRH FD7h TMR0H FB7h CCPR2L F97h TRISF F77h PR4

(3)

F57h UEP11

FF6h TBLPTRL FD6h TMR0L FB6h CCP2CON F96h TRISE F76h T4CON F56h UEP10

FF5h TABLAT FD5h T0CON FB5h ECCP3AS F95h TRISD F75h CCPR4H F55h UEP9

FF4h PRODH FD4h FB4h ECCP3DEL F94h TRISC F74h CCPR4L F54h UEP8

FF3h PRODL FD3h OSCCON

(3)

FB3h CCPR3H F93h TRISB F73h CCP4CON F53h UEP7

FF2h INTCON FD2h CM1CON FB2h CCPR3L F92h TRISA F72h CCPR5H F52h UEP6

FF1h INTCON2 FD1h CM2CON FB1h CCP3CON F91h LATJ

(2)

F71h CCPR5L F51h UEP5

FF0h INTCON3 FD0h RCON FB0h SPBRG1 F90h LATH

(2)

F70h CCP5CON F50h UEP4

FEFh INDF0

(1)

FCFh TMR1H

(3)

FAFh RCREG1 F8Fh LATG F6Fh SSP2BUF F4Fh UEP3

FEEh POSTINC0

(1)

FCEh TMR1L

(3)

FAEh TXREG1 F8Eh LATF F6Eh SSP2ADD F4Eh UEP2

FEDh POSTDEC0

(1)

FCDh T1CON

(3)

FADh TXSTA1 F8Dh LATE F6Dh SSP2STAT F4Dh UEP1

FECh PREINC0

(1)

FCCh TMR2

(3)

FACh RCSTA1 F8Ch LATD F6Ch SSP2CON1 F4Ch UEP0

FEBh PLUSW0

(1)

FCBh PR2

(3)

FABh SPBRG2 F8Bh LATC F6Bh SSP2CON2 F4Bh PMCONH

FEAh FSR0H FCAh T2CON FAAh RCREG2 F8Ah LATB F6Ah CMSTAT F4Ah PMCONL

FE9h FSR0L FC9h SSP1BUF FA9h TXREG2 F89h LATA F69h PMADDRH

(4)

F49h PMMODEH

FE8h WREG FC8h SSP1ADD FA8h TXSTA2 F88h PORTJ

(2)

F68h PMADDRL

(4)

F48h PMMODEL

FE7h INDF1

(1)

FC7h SSP1STAT FA7h EECON2 F87h PORTH

(2)

F67h PMDIN1H F47h PMDOUT2H

FE6h POSTINC1

(1)

FC6h SSP1CON1 FA6h EECON1 F86h PORTG F66h PMDIN1L F46h PMDOUT2L

FE5h POSTDEC1

(1)

FC5h SSP1CON2 FA5h IPR3 F85h PORTF F65h UCON F45h PMDIN2H

FE4h PREINC1

(1)

FC4h ADRESH FA4h PIR3 F84h PORTE F64h USTAT F44h PMDIN2L

FE3h PLUSW1

(1)

FC3h ADRESL FA3h PIE3 F83h PORTD F63h UEIR F43h PMEH

FE2h FSR1H FC2h ADCON0

(3)

FA2h IPR2 F82h PORTC F62h UIR F42h PMEL

FE1h FSR1L FC1h ADCON1

(3)

FA1h PIR2 F81h PORTB F61h UFRMH F41h PMSTATH

FE0h BSR FC0h WDTCON FA0h PIE2 F80h PORTA F60h UFRML F40h PMSTATL

Note 1: This is not a physical register.

2: This register is not available on 64-pin devices.

3: This register shares the same address with another register (see Table 5-4 for alternate register).

4: PMADDRH and PMDOUTH share the same address and PMADDRL and PMDOUTL share the same address. PMADDRx is used in Master

modes and PMDOUTx is used in Slave modes.

PIC18F87J50 FAMILY

5.3.5.1 Shared Address SFRs

In several locations in the SFR bank, a single address

is used to access two different hardware registers. In

these cases, a “legacy” register of the standard PIC18

SFR set (such as OSCCON, T1CON, etc.) shares its

address with an alternate register. These alternate reg-

isters are associated with enhanced configuration

options for peripherals, or with new device features not

included in the standard PIC18 SFR map. A complete

list of shared register addresses and the registers

associated with them is provided in Table 5-4.

Access to the alternate registers is enabled in software

by setting the ADSHR bit in the WDTCON register

(Register 5-3). ADSHR must be manually set or

cleared to access the alternate or legacy registers, as

required. Since the bit remains in a given state until

changed, users should always verify the state of

ADSHR before writing to any of the shared SFR

addresses.

5.3.5.2 Context Defined SFRs

In addition to the shared address SFRs, there are sev-

eral registers that share the same address in the SFR

space, but are not accessed with the ADSHR bit.

Instead, the register’s definition and use depends on

the operating mode of its associated peripheral. These

registers are:

• SSPxADD and SSPxMSK: These are two sepa-

rate hardware registers, accessed through a

single SFR address. The operating mode of the

MSSP modules determines which register is

being accessed. See Section 19.4.3.4 “7-Bit

Address Masking Mode” for additional details.

• PMADDRH/L and PMDOUT2H/L: In this case,

these named buffer pairs are actually the same

physical registers. The PMP module’s operating

mode determines what function the registers take

on. See Section 11.1.2 “Data Registers” for

additional details.

TABLE 5-4: SHARED SFR ADDRESSES FOR PIC18F87J50 FAMILY DEVICES

Address Name Address Name Address Name

FD3h (D) OSCCON

FCDh

(D) T1CON FC2h (D) ADCON0

(A) REFOCON (A) ODCON3 (A) ANCON1

FCFh (D) TMR1H

FCCh

(D) TMR2 FC1h (D) ADCON1

(A) ODCON1 (A) PADCFG1 (A) ANCON0

FCEh (D) TMR1L

FCBh

(D) PR2 F77h (D) PR4

(A) ODCON2 (A) MEMCON(1) (A) CVRCON

Legend: (D) = Default SFR, accessible only when ADSHR = 0; (A) = Alternate SFR, accessible only when ADSHR = 1.

Note 1: Implemented in 80-pin devices only.

R/W-0 R-x U-0 R/W-0 U-0 U-0 U-0 U-0

REGSLP LVDSTAT — ADSHR — — —SWDTEN

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 REGSLP: Voltage Regulator Low-Power Operation Enable bit

For details of bit operation, see Register 25-9 on page 359.

bit 6 LVDSTAT: Low-Voltage Detect Status bit

1 = VDDCORE > 2.45V nominal

0 = VDDCORE < 2.45V nominal

bit 5 Unimplemented: Read as ‘0’

bit 4 ADSHR: Shared Address SFR Select bit

1 = Alternate SFR is selected

0 = Default (legacy) SFR is selected

bit 3-1 Unimplemented: Read as ‘0’

bit 0 SWDTEN: Software Controlled Watchdog Timer Enable bit

For details of bit operation, see Register 25-9.

PIC18F87J50 FAMILY

TABLE 5-5: REGISTER FILE SUMMARY (PIC18F87J50 FAMILY)

File Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on

POR, BOR

Details

Page:

TOSU — — — Top-of-Stack Upper Byte (TOS<20:16>) ---0 0000 61, 73

TOSH Top-of-Stack High Byte (TOS<15:8>) 0000 0000 61, 73

TOSL Top-of-Stack Low Byte (TOS<7:0>) 0000 0000 61, 73

STKPTR STKFUL STKUNF — SP4 SP3 SP2 SP1 SP0 00-0 0000 61, 74

PCLATU ——bit 21

(1) Holding Register for PC<20:16> ---0 0000 61, 73

PCLATH Holding Register for PC<15:8> 0000 0000 61, 73

PCL PC Low Byte (PC<7:0>) 0000 0000 61, 73

TBLPTRU —— bit 21 Program Memory Table Pointer Upper Byte (TBLPTR<20:16>) --00 0000 61, 106

TBLPTRH Program Memory Table Pointer High Byte (TBLPTR<15:8>) 0000 0000 61, 106

TBLPTRL Program Memory Table Pointer Low Byte (TBLPTR<7:0>) 0000 0000 61, 106

TABLAT Program Memory Table Latch 0000 0000 61, 106

PRODH Product Register High Byte xxxx xxxx 61, 119

PRODL Product Register Low Byte xxxx xxxx 61, 119

INTCON GIE/GIEH PEIE/GIEL TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 0000 000x 61, 123

INTCON2 RBPU INTEDG0 INTEDG1 INTEDG2 INTEDG3 TMR0IP INT3IP RBIP 1111 1111 61, 123

INTCON3 INT2IP INT1IP INT3IE INT2IE INT1IE INT3IF INT2IF INT1IF 1100 0000 61, 123

INDF0 Uses contents of FSR0 to address data memory – value of FSR0 not changed (not a physical register) N/A 61, 91

POSTINC0 Uses contents of FSR0 to address data memory – value of FSR0 post-incremented (not a physical register) N/A 61, 92

POSTDEC0 Uses contents of FSR0 to address data memory – value of FSR0 post-decremented (not a physical register) N/A 61, 92

PREINC0 Uses contents of FSR0 to address data memory – value of FSR0 pre-incremented (not a physical register) N/A 61, 92

PLUSW0 Uses contents of FSR0 to address data memory – value of FSR0 pre-incremented (not a physical register) –

value of FSR0 offset by W

N/A 61, 92

FSR0H — — — — Indirect Data Memory Address Pointer 0 High Byte ---- xxxx 61, 91

FSR0L Indirect Data Memory Address Pointer 0 Low Byte xxxx xxxx 61, 91

WREG Working Register xxxx xxxx 61, 75

INDF1 Uses contents of FSR1 to address data memory – value of FSR1 not changed (not a physical register) N/A 61, 91

POSTINC1 Uses contents of FSR1 to address data memory – value of FSR1 post-incremented (not a physical register) N/A 61, 92

POSTDEC1 Uses contents of FSR1 to address data memory – value of FSR1 post-decremented (not a physical register) N/A 61, 92

PREINC1 Uses contents of FSR1 to address data memory – value of FSR1 pre-incremented (not a physical register) N/A 61, 92

PLUSW1 Uses contents of FSR1 to address data memory – value of FSR1 pre-incremented (not a physical register) –

value of FSR1 offset by W

N/A 61, 92

FSR1H — — — — Indirect Data Memory Address Pointer 1 High Byte ---- xxxx 61, 91

FSR1L Indirect Data Memory Address Pointer 1 Low Byte xxxx xxxx 61, 91

BSR — — — — Bank Select Register ---- 0000 61, 78

INDF2 Uses contents of FSR2 to address data memory – value of FSR2 not changed (not a physical register) N/A 62, 91

POSTINC2 Uses contents of FSR2 to address data memory – value of FSR2 post-incremented (not a physical register) N/A 62, 92

POSTDEC2 Uses contents of FSR2 to address data memory – value of FSR2 post-decremented (not a physical register) N/A 62, 92

PREINC2 Uses contents of FSR2 to address data memory – value of FSR2 pre-incremented (not a physical register) N/A 62, 92

PLUSW2 Uses contents of FSR2 to address data memory – value of FSR2 pre-incremented (not a physical register) –

value of FSR2 offset by W

N/A 62, 92

FSR2H — — — — Indirect Data Memory Address Pointer 2 High Byte ---- xxxx 62, 91

Legend: x = unknown, u = unchanged, - = unimplemented, q = value depends on condition. Bold indicates shared-access SFRs.

Note 1: Bit 21 of the PC is only available in Serial Programming modes.

2: Default (legacy) SFR at this address, available when WDTCON<4> = 0.

3: Configuration SFR, overlaps with default SFR at this address; available only when WDTCON<4> = 1.

4: Reset value is ‘0’ when Two-Speed Start-up is enabled and ‘1’ if disabled.

5: The SSPxMSK registers are only accessible when SSPxCON2<3:0> = 1001.

6: Alternate names and definitions for these bits when the MSSP module is operating in I2C™ Slave mode. See Section 19.4.3.2 “Address

Masking Modes” for details

7: These bits and/or registers are only available in 80-pin devices; otherwise, they are unimplemented and read as ‘0’. Reset values are

shown for 80-pin devices.

8: The PMADDRH/PMDOUT1H and PMADDRL/PMDOUT1L register pairs share the physical registers and addresses, but have different

functions determined by the module’s operating mode. See Section 11.1.2 “Data Registers” for more information.

PIC18F87J50 FAMILY

FSR2L Indirect Data Memory Address Pointer 2 Low Byte xxxx xxxx 62, 91

STATUS — — —NOVZDCC---x xxxx 62, 89

TMR0H Timer0 Register High Byte 0000 0000 62, 193

TMR0L Timer0 Register Low Byte xxxx xxxx 62, 193

T0CON TMR0ON T08BIT T0CS T0SE PSA T0PS2 T0PS1 T0PS0 1111 1111 62, 192

OSCCON(2)/ IDLEN IRCF2 IRCF1 IRCF0 OSTS(4) — SCS1 SCS0 0110 q100 62, 44

REFOCON(3) ROON — ROSSLP ROSEL RODIV3 RODIV2 RODIV1 RODIV0 0-00 0000 62, 45

CM1CON CON COE CPOL EVPOL1 EVPOL0 CREF CCH1 CCH0 0001 1111 62, 345

CM2CON CON COE CPOL EVPOL1 EVPOL0 CREF CCH1 CCH0 0001 1111 62, 345

RCON IPEN —CMRI TO PD POR BOR 0-11 1100 60, 62,

135

TMR1H(2)/ Timer1 Register High Byte xxxx xxxx 62, 196

ODCON1(3) — — — CCP5OD CCP4OD ECCP3OD ECCP2OD ECCP1OD ---0 0000 62, 139

TMR1L(2)/ Timer1 Register Low Byte xxxx xxxx 62, 196

ODCON2(3) —————— U2OD U1OD ---- --00 62, 139

T1CON(2)/ RD16 T1RUN T1CKPS1 T1CKPS0 T1OSCEN T1SYNC TMR1CS TMR1ON 0000 0000 62, 196

ODCON3(3) —————— SPI2OD SPI1OD ---- --00 62, 139

TMR2(2)/ Timer2 Register 0000 0000 62, 201

PADCFG1(3) ———————PMPTTL---- ---0 62, 140

PR2(2)/ Timer2 Period Register 1111 1111 62, 201

MEMCON(3) EDBIS —WAIT1WAIT0——WM1WMO0-00 --00 62, 108

T2CON — T2OUTPS3 T2OUTPS2 T2OUTPS1 T2OUTPS0 TMR2ON T2CKPS1 T2CKPS0 -000 0000 62, 201

SSP1BUF MSSP1 Receive Buffer/Transmit Register xxxx xxxx 62, 243,

278

SSP1ADD/ MSSP1 Address Register (I2C™ Slave mode), MSSP1 Baud Rate Reload Register (I2C™ Master mode) 0000 0000 62, 248

SSP1MSK(5) MSK7 MSK6 MSK5 MSK4 MSK3 MSK2 MSK1 MSK0 1111 1111 62, 250

SSP1STAT SMP CKE D/A PSR/WUA BF 0000 0000 62, 233,

244

SSP1CON1 WCOL SSPOV SSPEN CKP SSPM3 SSPM2 SSPM1 SSPM0 0000 0000 62, 233,

245

SSP1CON2 GCEN ACKSTAT ACKDT ACKEN RCEN PEN RSEN SEN 0000 0000 62, 233,

246

GCEN ACKSTAT ADMSK5(6) ADMSK4(6) ADMSK3(6) ADMSK2(6) ADMSK1(6) SEN

ADRESH A/D Result Register High Byte xxxx xxxx 63, 310

ADRESL A/D Result Register Low Byte xxxx xxxx 63, 310

ADCON0(2)/ VCFG1 VCFG0 CHS3 CHS2 CHS1 CHS0 GO/DONE ADON 0000 0000 63, 301

ANCON1(3) PCFG15 PCFG14 PCFG13 PCFG12 PCFG11 PCFG10 — — 0000 00-- 63, 301

ADCON1(2)/ ADFM ADCAL ACQT2 ACQT1 ACQT0 ADCS2 ADCS1 ADCS0 0000 0000 63, 301

ANCON0(3) PCFG7 —— PCFG4 PCFG3 PCFG2 PCFG1 PCFG0 0--0 0000 63, 301

WDTCON REGSLP LVDSTAT —ADSHR———SWDTEN0x-0 ---0 63, 358

TABLE 5-5: REGISTER FILE SUMMARY (PIC18F87J50 FAMILY) (CONTINUED)

File Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on

POR, BOR

Details

Page:

Legend: x = unknown, u = unchanged, - = unimplemented, q = value depends on condition. Bold indicates shared-access SFRs.

Note 1: Bit 21 of the PC is only available in Serial Programming modes.

2: Default (legacy) SFR at this address, available when WDTCON<4> = 0.

3: Configuration SFR, overlaps with default SFR at this address; available only when WDTCON<4> = 1.

4: Reset value is ‘0’ when Two-Speed Start-up is enabled and ‘1’ if disabled.

5: The SSPxMSK registers are only accessible when SSPxCON2<3:0> = 1001.

6: Alternate names and definitions for these bits when the MSSP module is operating in I2C™ Slave mode. See Section 19.4.3.2 “Address

Masking Modes” for details

7: These bits and/or registers are only available in 80-pin devices; otherwise, they are unimplemented and read as ‘0’. Reset values are

shown for 80-pin devices.

8: The PMADDRH/PMDOUT1H and PMADDRL/PMDOUT1L register pairs share the physical registers and addresses, but have different

functions determined by the module’s operating mode. See Section 11.1.2 “Data Registers” for more information.

PIC18F87J50 FAMILY

ECCP1AS ECCP1ASE ECCP1AS2 ECCP1AS1 ECCP1AS0 PSS1AC1 PSS1AC0 PSS1BD1 PSS1BD0 0000 0000 63, 232

ECCP1DEL P1RSEN P1DC6 P1DC5 P1DC4 P1DC3 P1DC2 P1DC1 P1DC0 0000 0000 63, 232

CCPR1H Capture/Compare/PWM Register 1 HIgh Byte xxxx xxxx 63, 232

CCPR1L Capture/Compare/PWM Register 1 Low Byte xxxx xxxx 63, 232

CCP1CON P1M1 P1M0 DC1B1 DC1B0 CCP1M3 CCP1M2 CCP1M1 CCP1M0 0000 0000 63, 232

ECCP2AS ECCP2ASE ECCP2AS2 ECCP2AS1 ECCP2AS0 PSS2AC1 PSS2AC0 PSS2BD1 PSS2BD0 0000 0000 63, 232

ECCP2DEL P2RSEN P2DC6 P2DC5 P2DC4 P2DC3 P2DC2 P2DC1 P2DC0 0000 0000 63, 232

CCPR2H Capture/Compare/PWM Register 2 High Byte xxxx xxxx 63, 232

CCPR2L Capture/Compare/PWM Register 2 Low Byte xxxx xxxx 63, 232

CCP2CON P2M1 P2M0 DC2B1 DC2B0 CCP2M3 CCP2M2 CCP2M1 CCP2M0 0000 0000 63, 232

ECCP3AS ECCP3ASE ECCP3AS2 ECCP3AS1 ECCP3AS0 PSS3AC1 PSS3AC0 PSS3BD1 PSS3BD0 0000 0000 63, 232

ECCP3DEL P3RSEN P3DC6 P3DC5 P3DC4 P3DC3 P3DC2 P3DC1 P3DC0 0000 0000 63, 232

CCPR3H Capture/Compare/PWM Register 3 High Byte xxxx xxxx 63, 232

CCPR3L Capture/Compare/PWM Register 3 Low Byte xxxx xxxx 63, 232

CCP3CON P3M1 P3M0 DC3B1 DC3B0 CCP3M3 CCP3M2 CCP3M1 CCP3M0 0000 0000 63, 232

SPBRG1 EUSART1 Baud Rate Generator Register Low Byte 0000 0000 63, 283

RCREG1 EUSART1 Receive Register 0000 0000 63, 291,

292

TXREG1 EUSART1 Transmit Register xxxx xxxx 63, 289,

290

TXSTA1 CSRC TX9 TXEN SYNC SENDB BRGH TRMT TX9D 0000 0010 63, 289

RCSTA1 SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 0000 000x 63, 291

SPBRG2 EUSART2 Baud Rate Generator Register Low Byte 0000 0000 63, 283

RCREG2 EUSART2 Receive Register 0000 0000 63, 291,

292

TXREG2 EUSART2 Transmit Register 0000 0000 63, 289,

290

TXSTA2 CSRC TX9 TXEN SYNC SENDB BRGH TRMT TX9D 0000 0010 63, 289

EECON2 Program Memory Control Register 2 (not a physical register) ---- ---- 63, 98

EECON1 —— WPROG FREE WRERR WREN WR —--00 x00- 63, 98

IPR3 SSP2IP BCL2IP RC2IP TX2IP TMR4IP CCP5IP CCP4IP CCP3IP 1111 1111 64, 132

PIR3 SSP2IF BCL2IF RC2IF TX2IF TMR4IF CCP5IF CCP4IF CCP3IF 0000 0000 64, 126

PIE3 SSP2IE BCL2IE RC2IE TX2IE TMR4IE CCP5IE CCP4IE CCP3IE 0000 0000 64, 129

IPR2 OSCFIP CM2IP CM1IP USBIP BCL1IP LVDIP TMR3IP CCP2IP 1111 1111 64, 132

PIR2 OSCFIF CM2IF CM1IF USBIF BCL1IF LVDIF TMR3IF CCP2IF 0000 0000 64, 126

PIE2 OSCFIE CM2IE CM1IE USBIE BCL1IE LVDIE TMR3IE CCP2IE 0000 0000 64, 129

IPR1 PMPIP ADIP RC1IP TX1IP SSP1IP CCP1IP TMR2IP TMR1IP 1111 1111 64, 132

PIR1 PMPIF ADIF RC1IF TX1IF SSP1IF CCP1IF TMR2IF TMR1IF 0000 0000 64, 126

PIE1 PMPIE ADIE RC1IE TX1IE SSP1IE CCP1IE TMR2IE TMR1IE 0000 0000 64, 129

RCSTA2 SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 0000 000x 64, 291

OSCTUNE INTSRC PLLEN TUN5 TUN4 TUN3 TUN2 TUN1 TUN0 0000 0000 64, 39

TABLE 5-5: REGISTER FILE SUMMARY (PIC18F87J50 FAMILY) (CONTINUED)

File Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on

POR, BOR

Details

Page:

Legend: x = unknown, u = unchanged, - = unimplemented, q = value depends on condition. Bold indicates shared-access SFRs.

Note 1: Bit 21 of the PC is only available in Serial Programming modes.

2: Default (legacy) SFR at this address, available when WDTCON<4> = 0.

3: Configuration SFR, overlaps with default SFR at this address; available only when WDTCON<4> = 1.

4: Reset value is ‘0’ when Two-Speed Start-up is enabled and ‘1’ if disabled.

5: The SSPxMSK registers are only accessible when SSPxCON2<3:0> = 1001.

6: Alternate names and definitions for these bits when the MSSP module is operating in I2C™ Slave mode. See Section 19.4.3.2 “Address

Masking Modes” for details

7: These bits and/or registers are only available in 80-pin devices; otherwise, they are unimplemented and read as ‘0’. Reset values are

shown for 80-pin devices.

8: The PMADDRH/PMDOUT1H and PMADDRL/PMDOUT1L register pairs share the physical registers and addresses, but have different

functions determined by the module’s operating mode. See Section 11.1.2 “Data Registers” for more information.

PIC18F87J50 FAMILY

TRISJ(7) TRISJ7 TRISJ6 TRISJ5 TRISJ4 TRISJ3 TRISJ2 TRISJ1 TRISJ0 1111 1111 64, 165

TRISH(7) TRISH7 TRISH6 TRISH5 TRISH4 TRISH3 TRISH2 TRISH1 TRISH0 1111 1111 64, 163

TRISG — — — TRISG4 TRISG3 TRISG2TRISG1TRISG0---1 1111 64, 160

TRISF TRISF7 TRISF6 TRISF5 TRISF4 TRISF3 TRISF2 — — 111- -1-- 64, 157

TRISE TRISE7 TRISE6 TRISE5 TRISE4 TRISE3 TRISE2 TRISE1 TRISE0 1111 1111 64, 154

TRISD TRISD7 TRISD6 TRISD5 TRISD4 TRISD3 TRISD2 TRISD1 TRISD0 1111 1111 64, 151

TRISC TRISC7 TRISC6 TRISC5 TRISC4 TRISC3 TRISC2 TRISC1 TRISC0 1111 1111 64, 148

TRISB TRISB7 TRISB6 TRISB5 TRISB4 TRISB3 TRISB2 TRISB1 TRISB0 1111 1111 64, 145

TRISA —— TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 --11 1111 64, 142

LATJ(7) LATJ7LATJ6LATJ5LATJ4LATJ3LATJ2LATJ1LATJ0xxxx xxxx 64, 165

LATH(7) LATH7 LATH6 LATH5 LATH4 LATH3 LATH2 LATH1 LATH0 xxxx xxxx 64, 163

LATG — — — L ATG4 LATG3 LATG 2 L AT G1 LATG0 ---x xxxx 64, 160

LATF LATF7 LATF6 LATF5 LATF4 LATF3 LATF2 — — xxxx xx-- 64, 157

LATE LATE7 LATE6 LATE5 LATE4 LATE3 LATE2 LATE1 LATE0 xxxx xxxx 64, 154

LATD LATD7 LATD6 LATD5 LATD4 LATD3 LATD2 LATD1 LATD0 xxxx xxxx 64, 151

LATC LATC7 LATC6 LATC5 LATC4 LATC3 LATC2 LATC1 LATC0 xxxx xxxx 64, 148

LATB LATB7 LATB6 LATB5 LATB4 LATB3 LATB2 LATB1 LATB0 xxxx xxxx 64, 145

LATA —— LATA5 LATA4 LATA3 LATA2 LATA1 LATA0 --xx xxxx 64, 142

PORTJ(7) RJ7 RJ6 RJ5 RJ4 RJ3 RJ2 RJ1 RJ0 xxxx xxxx 65, 165

PORTH(7) RH7 RH6 RH5 RH4 RH3 RH2 RH1 RH0 0000 xxxx 65, 163

PORTG RDPU REPU RJPU(7) RG4 RG3 RG2 RG1 RG0 000x xxxx 65, 160

PORTF RF7 RF6 RF5 RF4 RF3 RF2 — — x00x x0-- 65, 157

PORTE RE7 RE6 RE5 RE4 RE3 RE2 RE1 RE0 xxxx xxxx 65, 154

PORTD RD7 RD6 RD5 RD4 RD3 RD2 RD1 RD0 xxxx xxxx 65, 151

PORTC RC7 RC6 RC5 RC4 RC3 RC2 RC1 RC0 xxxx xxxx 65, 148

PORTB RB7 RB6 RB5 RB4 RB3 RB2 RB1 RB0 xxxx xxxx 65, 145

PORTA —— RA5 RA4 RA3 RA2 RA1 RA0 --0x 0000 65, 142

SPBRGH1 EUSART1 Baud Rate Generator Register High Byte 0000 0000 65, 283

BAUDCON1 ABDOVF RCIDL DTRXP SCKP BRG16 — WUE ABDEN 0100 0-00 65, 283

SPBRGH2 EUSART2 Baud Rate Generator Register High Byte 0000 0000 65, 283

BAUDCON2 ABDOVF RCIDL DTRXP SCKP BRG16 — WUE ABDEN 0100 0-00 65, 283

TMR3H Timer3 Register High Byte xxxx xxxx 65, 208

TMR3L Timer3 Register Low Byte xxxx xxxx 65, 208

T3CON RD16 T3CCP2 T3CKPS1 T3CKPS0 T3CCP1 T3SYNC TMR3CS TMR3ON 0000 0000 65, 208

TMR4 Timer4 Register 0000 0000 65, 207

PR4(2)/ Timer4 Period Register 1111 1111 65, 208

CVRCON(3) CVREN CVROE CVRR CVRSS CVR3 CVR2 CVR1 CVR0 0000 0000 65, 346

T4CON — T4OUTPS3 T4OUTPS2 T4OUTPS1 T4OUTPS0 TMR4ON T4CKPS1 T4CKPS0 -000 0000 65, 207

TABLE 5-5: REGISTER FILE SUMMARY (PIC18F87J50 FAMILY) (CONTINUED)

File Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on

POR, BOR

Details

Page:

Legend: x = unknown, u = unchanged, - = unimplemented, q = value depends on condition. Bold indicates shared-access SFRs.

Note 1: Bit 21 of the PC is only available in Serial Programming modes.

2: Default (legacy) SFR at this address, available when WDTCON<4> = 0.

3: Configuration SFR, overlaps with default SFR at this address; available only when WDTCON<4> = 1.

4: Reset value is ‘0’ when Two-Speed Start-up is enabled and ‘1’ if disabled.

5: The SSPxMSK registers are only accessible when SSPxCON2<3:0> = 1001.

6: Alternate names and definitions for these bits when the MSSP module is operating in I2C™ Slave mode. See Section 19.4.3.2 “Address

Masking Modes” for details

7: These bits and/or registers are only available in 80-pin devices; otherwise, they are unimplemented and read as ‘0’. Reset values are

shown for 80-pin devices.

8: The PMADDRH/PMDOUT1H and PMADDRL/PMDOUT1L register pairs share the physical registers and addresses, but have different

functions determined by the module’s operating mode. See Section 11.1.2 “Data Registers” for more information.

PIC18F87J50 FAMILY

CCPR4H Capture/Compare/PWM Register 4 High Byte xxxx xxxx 65, 210

CCPR4L Capture/Compare/PWM Register 4 Low Byte xxxx xxxx 65, 210

CCP4CON —— DC4B1 DC4B0 CCP4M3 CCP4M2 CCP4M1 CCP4M0 --00 0000 65, 210

CCPR5H Capture/Compare/PWM Register 5 High Byte xxxx xxxx 65, 210

CCPR5L Capture/Compare/PWM Register 5 Low Byte xxxx xxxx 65, 210

CCP5CON —— DC5B1 DC5B0 CCP5M3 CCP5M2 CCP5M1 CCP5M0 --00 0000 65, 210

SSP2BUF MSSP2 Receive Buffer/Transmit Register xxxx xxxx 65, 243,

278

SSP2ADD/ MSSP2 Address Register (I2C™ Slave mode), MSSP2 Baud Rate Reload Register (I2C Master mode) 0000 0000 65, 243

SSP2MSK(5) MSK7 MSK6 MSK5 MSK4 MSK3 MSK2 MSK1 MSK0 0000 0000 65, 250

SSP2STAT SMP CKE D/A PSR/WUA BF 1111 1111 65, 233,

244

SSP2CON1 WCOL SSPOV SSPEN CKP SSPM3 SSPM2 SSPM1 SSPM0 0000 0000 65, 233,

245

SSP2CON2 GCEN ACKSTAT ACKDT ACKEN RCEN PEN RSEN SEN 0000 0000 65, 233,

245

GCEN ACKSTAT ADMSK5(6) ADMSK4(6) ADMSK3(6) ADMSK2(6) ADMSK1(6) SEN

CMSTAT — — — — — — COUT2 COUT1 ---- --11 65, 339

PMADDRH/ CS2 CS1 Parallel Master Port Address High Byte 0000 0000 66, 174

PMDOUT1H(8) Parallel Port Out Data High Byte (Buffer 1) 0000 0000 66, 177

PMADDRL/ Parallel Master Port Address Low Byte 0000 0000 66, 174

PMDOUT1L(8) Parallel Port Out Data Low Byte (Buffer 0) 0000 0000 66, 174

PMDIN1H Parallel Port In Data High Byte (Buffer 1) 0000 0000 66, 174

PMDIN1L Parallel Port In Data Low Byte (Buffer 0) 0000 0000 66, 174

UCON — PPBRST SE0 PKTDIS USBEN RESUME SUSPND —-0x0 000- 66, 312

USTAT — ENDP3 ENDP2 ENDP1 ENDP0 DIR PPBI —-xxx xxx- 66, 316

UEIR BTSEF —— BTOEF DFN8EF CRC16EF CRC5EF PIDEF 0--0 0000 66, 329

UIR — SOFIF STALLIF IDLEIF TRNIF ACTVIF UERRIF URSTIF -000 0000 66, 326

UFRMH — — — — — FRM10 FRM9 FRM8 ---- -xxx 66, 318

UFRML FRM7 FRM6 FRM5 FRM4 FRM3 FRM2 FRM1 FRM0 xxxx xxxx 66, 318

UCFG UTEYE —— UPUEN UTRDIS FSEN PPB1 PPB0 00-0 0000 66, 313

UADDR — ADDR6 ADDR5 ADDR4 ADDR3 ADDR2 ADDR1 ADDR0 -000 0000 66, 318

UEIE BTSEE —— BTOEE DFN8EE CRC16EE CRC5EE PIDEE 0--0 0000 66, 330

UIE — SOFIE STALLIE IDLEIE TRNIE ACTVIE UERRIE URSTIE -000 0000 66, 328

UEP15 — — — EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL ---0 0000 66, 317

UEP14 — — — EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL ---0 0000 66, 317

UEP13 — — — EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL ---0 0000 66, 317

UEP12 — — — EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL ---0 0000 66, 317

UEP11 — — — EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL ---0 0000 66, 317

UEP10 — — — EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL ---0 0000 66, 317

UEP9 — — — EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL ---0 0000 66, 317

UEP8 — — — EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL ---0 0000 66, 317

TABLE 5-5: REGISTER FILE SUMMARY (PIC18F87J50 FAMILY) (CONTINUED)

File Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on

POR, BOR

Details

Page:

Legend: x = unknown, u = unchanged, - = unimplemented, q = value depends on condition. Bold indicates shared-access SFRs.

Note 1: Bit 21 of the PC is only available in Serial Programming modes.

2: Default (legacy) SFR at this address, available when WDTCON<4> = 0.

3: Configuration SFR, overlaps with default SFR at this address; available only when WDTCON<4> = 1.

4: Reset value is ‘0’ when Two-Speed Start-up is enabled and ‘1’ if disabled.

5: The SSPxMSK registers are only accessible when SSPxCON2<3:0> = 1001.

6: Alternate names and definitions for these bits when the MSSP module is operating in I2C™ Slave mode. See Section 19.4.3.2 “Address

Masking Modes” for details

7: These bits and/or registers are only available in 80-pin devices; otherwise, they are unimplemented and read as ‘0’. Reset values are

shown for 80-pin devices.

8: The PMADDRH/PMDOUT1H and PMADDRL/PMDOUT1L register pairs share the physical registers and addresses, but have different

functions determined by the module’s operating mode. See Section 11.1.2 “Data Registers” for more information.

PIC18F87J50 FAMILY

UEP7 — — — EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL ---0 0000 66, 317

UEP6 — — — EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL ---0 0000 66, 317

UEP5 — — — EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL ---0 0000 66, 317

UEP4 — — — EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL ---0 0000 66, 317

UEP3 — — — EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL ---0 0000 66, 317

UEP2 — — — EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL ---0 0000 66, 317

UEP1 — — — EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL ---0 0000 66, 317

UEP0 — — — EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL ---0 0000 66, 317

PMCONH PMPEN — PSIDL ADRMUX1 ADRMUX0 PTBEEN PTWREN PTRDEN 0-00 0000 66, 168

PMCONL CSF1 CSF0 ALP CS2P CS1P BEP WRSP RDSP 0000 0000 67, 169

PMMODEH BUSY IRQM1 IRQM0 INCM1 INCM0 MODE16 MODE1 MODE0 0000 0000 67, 170

PMMODEL WAITB1 WAITB0 WAITM3 WAITM2 WAITM1 WAITM0 WAITE1 WAITE0 0000 0000 67, 171

PMDOUT2H Parallel Port Out Data High Byte (Buffer 3) 0000 0000 67, 174

PMDOUT2L Parallel Port Out Data Low Byte (Buffer 2) 0000 0000 67, 174

PMDIN2H Parallel Port In Data High Byte (Buffer 3) 0000 0000 67, 174

PMDIN2L Parallel Port In Data Low Byte (Buffer 2) 0000 0000 67, 174

PMEH PTEN15 PTEN14 PTEN13 PTEN12 PTEN11 PTEN10 PTEN9 PTEN8 0000 0000 67, 171

PMEL PTEN7 PTEN6 PTEN5 PTEN4 PTEN3 PTEN2 PTEN1 PTEN0 0000 0000 67, 172

PMSTATH IBF IBOV —— IB3F IB2F IB1F IB0F 00-- 0000 67, 172

PMSTATL OBE OBUF —— OB3E OB2E OB1E OB0E 10-- 1111 67, 173

TABLE 5-5: REGISTER FILE SUMMARY (PIC18F87J50 FAMILY) (CONTINUED)

File Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on

POR, BOR

Details

Page:

Legend: x = unknown, u = unchanged, - = unimplemented, q = value depends on condition. Bold indicates shared-access SFRs.

Note 1: Bit 21 of the PC is only available in Serial Programming modes.

2: Default (legacy) SFR at this address, available when WDTCON<4> = 0.

3: Configuration SFR, overlaps with default SFR at this address; available only when WDTCON<4> = 1.

4: Reset value is ‘0’ when Two-Speed Start-up is enabled and ‘1’ if disabled.

5: The SSPxMSK registers are only accessible when SSPxCON2<3:0> = 1001.

6: Alternate names and definitions for these bits when the MSSP module is operating in I2C™ Slave mode. See Section 19.4.3.2 “Address

Masking Modes” for details

7: These bits and/or registers are only available in 80-pin devices; otherwise, they are unimplemented and read as ‘0’. Reset values are

shown for 80-pin devices.

8: The PMADDRH/PMDOUT1H and PMADDRL/PMDOUT1L register pairs share the physical registers and addresses, but have different

functions determined by the module’s operating mode. See Section 11.1.2 “Data Registers” for more information.

PIC18F87J50 FAMILY

5.3.6 STATUS REGISTER

The STATUS register, shown in Register 5-4, contains

the arithmetic status of the ALU. The STATUS register

can be the operand for any instruction, as with any

other register. If the STATUS register is the destination

for an instruction that affects the Z, DC, C, OV or N bits,

then the write to these five bits is disabled.

These bits are set or cleared according to the device

logic. Therefore, the result of an instruction with the

STATUS register as destination may be different than

intended. For example, CLRF STATUS will set the Z bit

but leave the other bits unchanged. The STATUS

mended, therefore, that only BCF, BSF, SWAPF,

MOVFF and MOVWF instructions are used to alter the

STATUS register because these instructions do not

affect the Z, C, DC, OV or N bits in the STATUS

For other instructions not affecting any Status bits, see

the instruction set summaries in Table 26-2 and

Table 26-3.

Note: The C and DC bits operate as a borrow and

digit borrow bit respectively, in subtraction.

U-0 U-0 U-0 R/W-x R/W-x R/W-x R/W-x R/W-x

— — —NOVZDC

(1) C(2)

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7-5 Unimplemented: Read as ‘0’

bit 4 N: Negative bit

This bit is used for signed arithmetic (2’s complement). It indicates whether the result was

negative (ALU MSB = 1).

1 = Result was negative

0 = Result was positive

bit 3 OV: Overflow bit

This bit is used for signed arithmetic (2’s complement). It indicates an overflow of the

7-bit magnitude which causes the sign bit (bit 7) to change state.

1 = Overflow occurred for signed arithmetic (in this arithmetic operation)

0 = No overflow occurred

bit 2 Z: Zero bit

1 = The result of an arithmetic or logic operation is zero

0 = The result of an arithmetic or logic operation is not zero

bit 1 DC: Digit carry/borrow bit(1)

For ADDWF, ADDLW, SUBLW and SUBWF instructions:

1 = A carry-out from the 4th low-order bit of the result occurred

0 = No carry-out from the 4th low-order bit of the result

bit 0 C: Carry/borrow bit(2)

For ADDWF, ADDLW, SUBLW and SUBWF instructions:

1 = A carry-out from the Most Significant bit of the result occurred

0 = No carry-out from the Most Significant bit of the result occurred

Note 1: For borrow, the polarity is reversed. A subtraction is executed by adding the 2’s complement of the second

operand. For rotate (RRF, RLF) instructions, this bit is loaded with either bit 4 or bit 3 of the source

2: For borrow, the polarity is reversed. A subtraction is executed by adding the 2’s complement of the second

operand. For rotate (RRF, RLF) instructions, this bit is loaded with either the high or low-order bit of the

source register.

PIC18F87J50 FAMILY

5.4 Data Addressing Modes

While the program memory can be addressed in only

one way – through the program counter – information

in the data memory space can be addressed in several

ways. For most instructions, the addressing mode is

fixed. Other instructions may use up to three modes,

depending on which operands are used and whether or

not the extended instruction set is enabled.

The addressing modes are:

• Inherent

• Literal

•Direct

•Indirect

An additional addressing mode, Indexed Literal Offset,

is available when the extended instruction set is

enabled (XINST Configuration bit = 1). Its operation is

discussed in greater detail in Section 5.6.1 “Indexed

Addressing with Literal Offset”.

5.4.1 INHERENT AND LITERAL

ADDRESSING

Many PIC18 control instructions do not need any

argument at all; they either perform an operation that

globally affects the device, or they operate implicitly on

one register. This addressing mode is known as

Inherent Addressing. Examples include SLEEP, RESET

and DAW.

Other instructions work in a similar way, but require an

additional explicit argument in the opcode. This is

known as Literal Addressing mode, because they

require some literal value as an argument. Examples

include ADDLW and MOVLW, which respectively, add or

move a literal value to the W register. Other examples

include CALL and GOTO, which include a 20-bit

program memory address.

5.4.2 DIRECT ADDRESSING

Direct Addressing specifies all or part of the source

and/or destination address of the operation within the

opcode itself. The options are specified by the

arguments accompanying the instruction.

In the core PIC18 instruction set, bit-oriented and

byte-oriented instructions use some version of Direct

Addressing by default. All of these instructions include

some 8-bit Literal Address as their Least Significant

Byte. This address specifies either a register address in

one of the banks of data RAM (Section 5.3.4 “General

Purpose Register File”), or a location in the Access

Bank (Section 5.3.3 “Access Bank”) as the data

source for the instruction.

The Access RAM bit ‘a’ determines how the address is

interpreted. When ‘a’ is ‘1’, the contents of the BSR

(Section 5.3.2 “Bank Select Register”) are used with

the address to determine the complete 12-bit address

of the register. When ‘a’ is ‘0’, the address is interpreted

as being a register in the Access Bank. Addressing that

uses the Access RAM is sometimes also known as

Direct Forced Addressing mode.

A few instructions, such as MOVFF, include the entire

12-bit address (either source or destination) in their

opcodes. In these cases, the BSR is ignored entirely.

The destination of the operation’s results is determined

by the destination bit ‘d’. When ‘d’ is ‘1’, the results are

stored back in the source register, overwriting its origi-

nal contents. When ‘d’ is ‘0’, the results are stored in

the W register. Instructions without the ‘d’ argument

have a destination that is implicit in the instruction; their

destination is either the target register being operated

on or the W register.

5.4.3 INDIRECT ADDRESSING

Indirect Addressing allows the user to access a location

in data memory without giving a fixed address in the

instruction. This is done by using File Select Registers

(FSRs) as pointers to the locations to be read or written

to. Since the FSRs are themselves located in RAM as

Special Function Registers, they can also be directly

manipulated under program control. This makes FSRs

very useful in implementing data structures such as

tables and arrays in data memory.

The registers for Indirect Addressing are also

implemented with Indirect File Operands (INDFs) that

permit automatic manipulation of the pointer value with

auto-incrementing, auto-decrementing or offsetting

with another value. This allows for efficient code using

loops, such as the example of clearing an entire RAM

bank in Example 5-5. It also enables users to perform

Indexed Addressing and other Stack Pointer

operations for program memory in data memory.

EXAMPLE 5-5: HOW TO CLEAR RAM

(BANK 1) USING

INDIRECT ADDRESSING

Note: The execution of some instructions in the

core PIC18 instruction set are changed

when the PIC18 extended instruction set is

enabled. See Section 5.6 “Data Memory

and the Extended Instruction Set” for

more information.

LFSR FSR0, 100h ;

NEXT CLRF POSTINC0 ; Clear INDF

; register then

; inc pointer

BTFSS FSR0H, 1 ; All done with

; Bank1?

BRA NEXT ; NO, clear next

CONTINUE ; YES, continue

PIC18F87J50 FAMILY

5.4.3.1 FSR Registers and the

INDF Operand

At the core of Indirect Addressing are three sets of

registers: FSR0, FSR1 and FSR2. Each represents a

pair of 8-bit registers, FSRnH and FSRnL. The four

upper bits of the FSRnH register are not used, so each

FSR pair holds a 12-bit value. This represents a value

that can address the entire range of the data memory

in a linear fashion. The FSR register pairs, then, serve

as pointers to data memory locations.

Indirect Addressing is accomplished with a set of

Indirect File Operands, INDF0 through INDF2. These

can be thought of as “virtual” registers: they are

mapped in the SFR space but are not physically imple-

mented. Reading or writing to a particular INDF register

actually accesses its corresponding FSR register pair.

A read from INDF1, for example, reads the data at the

address indicated by FSR1H:FSR1L. Instructions that

use the INDF registers as operands actually use the

contents of their corresponding FSR as a pointer to the

instruction’s target. The INDF operand is just a

convenient way of using the pointer.

Because Indirect Addressing uses a full 12-bit address,

data RAM banking is not necessary. Thus, the current

contents of the BSR and the Access RAM bit have no

effect on determining the target address.

FIGURE 5-9: INDIRECT ADDRESSING

FSR1H:FSR1L

Data Memory

000h

100h

200h

300h

F00h

E00h

FFFh

Bank 0

Bank 1

Bank 2

Bank 14

Bank 15

Bank 3

through

Bank 13

ADDWF, INDF1, 1

Using an instruction with one of the

Indirect Addressing registers as the

operand....

...uses the 12-bit address stored in

the FSR pair associated with that

...to determine the data memory

location to be used in that operation.

In this case, the FSR1 pair contains

FCCh. This means the contents of

location FCCh will be added to that

of the W register and stored back in

FCCh.

xxxx1111 11001100

PIC18F87J50 FAMILY

5.4.3.2 FSR Registers and POSTINC,

POSTDEC, PREINC and PLUSW

In addition to the INDF operand, each FSR register pair

also has four additional indirect operands. Like INDF,

these are “virtual” registers that cannot be indirectly

read or written to. Accessing these registers actually

accesses the associated FSR register pair, but also

performs a specific action on its stored value. They are:

• POSTDEC: accesses the FSR value, then

automatically decrements it by ‘1’ afterwards

• POSTINC: accesses the FSR value, then

automatically increments it by ‘1’ afterwards

• PREINC: increments the FSR value by ‘1’, then

uses it in the operation

• PLUSW: adds the signed value of the W register

(range of -127 to 128) to that of the FSR and uses

the new value in the operation

In this context, accessing an INDF register uses the

value in the FSR registers without changing them.

Similarly, accessing a PLUSW register gives the FSR

value offset by the value in the W register; neither value

is actually changed in the operation. Accessing the

other virtual registers changes the value of the FSR

registers.

Operations on the FSRs with POSTDEC, POSTINC

and PREINC affect the entire register pair; that is, roll-

overs of the FSRnL register from FFh to 00h carry over

to the FSRnH register. On the other hand, results of

these operations do not change the value of any flags

in the STATUS register (e.g., Z, N, OV, etc.).

The PLUSW register can be used to implement a form

of Indexed Addressing in the data memory space. By

manipulating the value in the W register, users can

reach addresses that are fixed offsets from pointer

addresses. In some applications, this can be used to

implement some powerful program control structure,

such as software stacks, inside of data memory.

5.4.3.3 Operations by FSRs on FSRs

Indirect Addressing operations that target other FSRs

or virtual registers represent special cases. For exam-

ple, using an FSR to point to one of the virtual registers

will not result in successful operations. As a specific

case, assume that FSR0H:FSR0L contains FE7h, the

address of INDF1. Attempts to read the value of the

INDF1, using INDF0 as an operand, will return 00h.

Attempts to write to INDF1, using INDF0 as the

operand, will result in a NOP.

On the other hand, using the virtual registers to write to

an FSR pair may not occur as planned. In these cases,

the value will be written to the FSR pair but without any

incrementing or decrementing. Thus, writing to INDF2

or POSTDEC2 will write the same value to the

FSR2H:FSR2L.

Since the FSRs are physical registers mapped in the

SFR space, they can be manipulated through all direct

operations. Users should proceed cautiously when

working on these registers, particularly if their code

uses Indirect Addressing.

Similarly, operations by Indirect Addressing are gener-

ally permitted on all other SFRs. Users should exercise

the appropriate caution that they do not inadvertently

change settings that might affect the operation of the

device.

5.5 Program Memory and the

Extended Instruction Set

The operation of program memory is unaffected by the

use of the extended instruction set.

Enabling the extended instruction set adds five

additional two-word commands to the existing PIC18

instruction set: ADDFSR, CALLW, MOVSF, MOVSS and

SUBFSR. These instructions are executed as described

in Section 5.2.4 “Two-Word Instructions”.

PIC18F87J50 FAMILY

5.6 Data Memory and the Extended

Instruction Set

Enabling the PIC18 extended instruction set (XINST

Configuration bit = 1) significantly changes certain

aspects of data memory and its addressing. Specifi-

cally, the use of the Access Bank for many of the core

PIC18 instructions is different. This is due to the intro-

duction of a new addressing mode for the data memory

space. This mode also alters the behavior of Indirect

Addressing using FSR2 and its associated operands.

What does not change is just as important. The size of

the data memory space is unchanged, as well as its

linear addressing. The SFR map remains the same.

Core PIC18 instructions can still operate in both Direct

and Indirect Addressing mode; inherent and literal

instructions do not change at all. Indirect Addressing

with FSR0 and FSR1 also remains unchanged.

5.6.1 INDEXED ADDRESSING WITH

LITERAL OFFSET

Enabling the PIC18 extended instruction set changes

the behavior of Indirect Addressing using the FSR2

proper conditions, instructions that use the Access

Bank – that is, most bit-oriented and byte-oriented

instructions – can invoke a form of Indexed Addressing

using an offset specified in the instruction. This special

addressing mode is known as Indexed Addressing with

Literal Offset, or Indexed Literal Offset mode.

When using the extended instruction set, this

addressing mode requires the following:

• The use of the Access Bank is forced (‘a’ = 0);

and

• The file address argument is less than or equal to

5Fh.

Under these conditions, the file address of the

instruction is not interpreted as the lower byte of an

address (used with the BSR in Direct Addressing) or as

an 8-bit address in the Access Bank. Instead, the value

is interpreted as an offset value to an Address Pointer

specified by FSR2. The offset and the contents of

FSR2 are added to obtain the target address of the

operation.

5.6.2 INSTRUCTIONS AFFECTED BY

INDEXED LITERAL OFFSET MODE

Any of the core PIC18 instructions that can use Direct

Addressing are potentially affected by the Indexed

Literal Offset Addressing mode. This includes all

byte-oriented and bit-oriented instructions, or almost

one-half of the standard PIC18 instruction set. Instruc-

tions that only use Inherent or Literal Addressing

modes are unaffected.

Additionally, byte-oriented and bit-oriented instructions

are not affected if they use the Access Bank (Access

RAM bit is ‘1’) or include a file address of 60h or above.

Instructions meeting these criteria will continue to

execute as before. A comparison of the different possi-

ble addressing modes when the extended instruction

set is enabled is shown in Figure 5-10.

Those who desire to use byte-oriented or bit-oriented

instructions in the Indexed Literal Offset mode should

note the changes to assembler syntax for this mode.

This is described in more detail in Section 26.2.1

“Extended Instruction Syntax”.

PIC18F87J50 FAMILY

FIGURE 5-10: COMPARING ADDRESSING OPTIONS FOR BIT-ORIENTED AND

BYTE-ORIENTED INSTRUCTIONS (EXTENDED INSTRUCTION SET ENABLED)

EXAMPLE INSTRUCTION: ADDWF, f, d, a (Opcode: 0010 01da ffff ffff)

When a = 0 and f ≥ 60h:

The instruction executes in

Direct Forced mode. ‘f’ is

interpreted as a location in the

Access RAM between 060h

and FFFh. This is the same as

locations F60h to FFFh

(Bank 15) of data memory.

Locations below 060h are not

available in this addressing

mode.

When a = 0 and f ≤ 5Fh:

The instruction executes in

Indexed Literal Offset mode. ‘f’

is interpreted as an offset to the

address value in FSR2. The

two are added together to

obtain the address of the target

address can be anywhere in

the data memory space.

Note that in this mode, the

correct syntax is now:

ADDWF [k], d

where ‘k’ is the same as ‘f’.

When a = 1 (all values of f):

The instruction executes in

Direct mode (also known as

Direct Long mode). ‘f’ is

interpreted as a location in

one of the 16 banks of the data

memory space. The bank is

designated by the Bank Select

can be in any implemented

bank in the data memory

space.

000h

060h

100h

F00h

F60h

FFFh

Valid range

00h

60h

FFh

Data Memory

Access RAM

Bank 0

Bank 1

through

Bank 14

Bank 15

SFRs

000h

060h

100h

F00h

F60h

FFFh

Data Memory

Bank 0

Bank 1

through

Bank 14

Bank 15

SFRs

FSR2H FSR2L

ffffffff001001da

000h

060h

100h

F00h

F60h

FFFh

Data Memory

Bank 0

Bank 1

through

Bank 14

Bank 15

SFRs

for ‘f’

BSR

00000000

PIC18F87J50 FAMILY

5.6.3 MAPPING THE ACCESS BANK IN

INDEXED LITERAL OFFSET MODE

The use of Indexed Literal Offset Addressing mode

effectively changes how the lower part of Access RAM

(00h to 5Fh) is mapped. Rather than containing just the

contents of the bottom part of Bank 0, this mode maps

the contents from Bank 0 and a user-defined “window”

that can be located anywhere in the data memory

space. The value of FSR2 establishes the lower bound-

ary of the addresses mapped into the window, while the

upper boundary is defined by FSR2 plus 95 (5Fh).

Addresses in the Access RAM above 5Fh are mapped

as previously described (see Section 5.3.3 “Access

Bank”). An example of Access Bank remapping in this

addressing mode is shown in Figure 5-11.

Remapping of the Access Bank applies only to opera-

tions using the Indexed Literal Offset mode. Operations

that use the BSR (Access RAM bit is ‘1’) will continue

to use Direct Addressing as before. Any Indirect or

Indexed Addressing operation that explicitly uses any

of the indirect file operands (including FSR2) will con-

tinue to operate as standard Indirect Addressing. Any

instruction that uses the Access Bank, but includes a

Addressing and the normal Access Bank map.

5.6.4 BSR IN INDEXED LITERAL

OFFSET MODE

Although the Access Bank is remapped when the

extended instruction set is enabled, the operation of the

BSR remains unchanged. Direct Addressing, using the

BSR to select the data memory bank, operates in the

same manner as previously described.

FIGURE 5-11: REMAPPING THE ACCESS BANK WITH INDEXED LITERAL

OFFSET ADDRESSING

Data Memory

000h

100h

200h

F60h

F00h

FFFh

Bank 1

Bank 15

Bank 2

through

Bank 14

SFRs

05Fh

ADDWF f, d, a

FSR2H:FSR2L = 120h

Locations in the region

from the FSR2 Pointer

(120h) to the pointer plus

05Fh (17Fh) are mapped

to the bottom of the

Access RAM (000h-05Fh).

Special Function Registers

at F60h through FFFh are

mapped to 60h through

FFh, as usual.

Bank 0 addresses below

5Fh are not available in

this mode. They can still

be addressed by using the

BSR.

Access Bank

00h

FFh

Bank 0

SFRs

Bank 1 “Window”

Not Accessible

Window

Example Situation:

120h

17Fh

5Fh

60h

PIC18F87J50 FAMILY

NOTES:

PIC18F87J50 FAMILY

6.0 FLASH PROGRAM MEMORY

The Flash program memory is readable, writable and

erasable during normal operation over the entire VDD

range.

A read from program memory is executed on one byte

at a time. A write to program memory is executed on

blocks of 64 bytes at a time or two bytes at a time. Pro-

gram memory is erased in blocks of 1024 bytes at a

time. A bulk erase operation may not be issued from

user code.

Writing or erasing program memory will cease

instruction fetches until the operation is complete. The

program memory cannot be accessed during the write

or erase, therefore, code cannot execute. An internal

programming timer terminates program memory writes

and erases.

A value written to program memory does not need to be

a valid instruction. Executing a program memory

location that forms an invalid instruction results in a

NOP.

6.1 Table Reads and Table Writes

In order to read and write program memory, there are

two operations that allow the processor to move bytes

between the program memory space and the data RAM:

• Table Read (TBLRD)

• Table Write (TBLWT)

The program memory space is 16 bits wide, while the

data RAM space is 8 bits wide. Table reads and table

writes move data between these two memory spaces

through an 8-bit register (TABLAT).

Table read operations retrieve data from program

memory and place it into the data RAM space.

Figure 6-1 shows the operation of a table read with

program memory and data RAM.

Table write operations store data from the data memory

space into holding registers in program memory. The

procedure to write the contents of the holding registers

into program memory is detailed in Section 6.5 “Writing

to Flash Program Memory”. Figure 6-2 shows the

operation of a table write with program memory and data

RAM.

Table operations work with byte entities. A table block

containing data, rather than program instructions, is not

required to be word-aligned. Therefore, a table block can

start and end at any byte address. If a table write is being

used to write executable code into program memory,

program instructions will need to be word-aligned.

FIGURE 6-1: TABLE READ OPERATION

Table Pointer(1)

Table Latch (8-bit)

Program Memory

TBLPTRH TBLPTRL

TABLAT

TBLPTRU

Instruction: TBLRD*

Note 1: Table Pointer register points to a byte in program memory.

Program Memory

(TBLPTR)

PIC18F87J50 FAMILY

FIGURE 6-2: TABLE WRITE OPERATION

6.2 Control Registers

Several control registers are used in conjunction with

the TBLRD and TBLWT instructions. These include the:

• EECON1 register

• EECON2 register

• TABLAT register

• TBLPTR registers

6.2.1 EECON1 AND EECON2 REGISTERS

The EECON1 register (Register 6-1) is the control

not a physical register; it is used exclusively in the

memory write and erase sequences. Reading

EECON2 will read all ‘0’s.

The WPROG bit, when set, will allow programming

two bytes per word on the execution of the WR com-

mand. If this bit is cleared, the WR command will result

in programming on a block of 64 bytes.

The FREE bit, when set, will allow a program memory

erase operation. When FREE is set, the erase

operation is initiated on the next WR command. When

FREE is clear, only writes are enabled.

The WREN bit, when set, will allow a write operation.

On power-up, the WREN bit is clear. The WRERR bit is

set in hardware when the WR bit is set and cleared

when the internal programming timer expires and the

write operation is complete.

The WR control bit initiates write operations. The bit

cannot be cleared, only set, in software. It is cleared in

hardware at the completion of the write operation.

Table Pointer(1) Table Latch (8-bit)

TBLPTRH TBLPTRL TABLAT

Program Memory

(TBLPTR)

TBLPTRU

Instruction: TBLWT*

Note 1: Table Pointer actually points to one of 64 holding registers, the address of which is determined by

TBLPTRL<5:0>. The process for physically writing data to the program memory array is discussed in

Section 6.5 “Writing to Flash Program Memory”.

Holding Registers

Program Memory

Note: During normal operation, the WRERR is

read as ‘1’. This can indicate that a write

operation was prematurely terminated by

a Reset, or a write operation was

attempted improperly.

PIC18F87J50 FAMILY

U-0 U-0 R/W-0 R/W-0 R/W-x R/W-0 R/S-0 U-0

—— WPROG FREE WRERR(1) WREN WR —

bit 7 bit 0

Legend: S = Settable only bit (cannot be cleared in software)

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7-6 Unimplemented: Read as ‘0’

bit 5 WPROG: One Word-Wide Program bit

1 = Program 2 bytes on the next WR command

0 = Program 64 bytes on the next WR command

bit 4 FREE: Flash Row Erase Enable bit

1 = Erase the program memory row addressed by TBLPTR on the next WR command

(cleared by completion of erase operation)

0 = Perform write only

bit 3 WRERR: Flash Program Error Flag bit(1)

1 = A write operation is prematurely terminated (any Reset during self-timed programming in normal

operation, or an improper write attempt)

0 = The write operation completed

bit 2 WREN: Flash Program Write Enable bit

1 = Allows write cycles to Flash program memory

0 = Inhibits write cycles to Flash program memory

bit 1 WR: Write Control bit

1 = Initiates a program memory erase cycle or write cycle

(The operation is self-timed and the bit is cleared by hardware once write is complete.

The WR bit can only be set (not cleared) in software.)

0 = Write cycle is complete

bit 0 Unimplemented: Read as ‘0’

Note 1: When a WRERR occurs, the EEPGD and CFGS bits are not cleared. This allows tracing of the error

condition.

PIC18F87J50 FAMILY

6.2.2 TABLE LATCH REGISTER (TABLAT)

The Table Latch (TABLAT) is an 8-bit register mapped

into the SFR space. The Table Latch register is used to

hold 8-bit data during data transfers between program

memory and data RAM.

6.2.3 TABLE POINTER REGISTER

(TBLPTR)

The Table Pointer (TBLPTR) register addresses a byte

within the program memory. The TBLPTR is comprised

of three SFR registers: Table Pointer Upper Byte, Table

Pointer High Byte and Table Pointer Low Byte

(TBLPTRU:TBLPTRH:TBLPTRL). These three regis-

ters join to form a 22-bit wide pointer. The low-order

21 bits allow the device to address up to 2 Mbytes of

program memory space. The 22nd bit allows access to

the device ID, the user ID and the Configuration bits.

The Table Pointer register, TBLPTR, is used by the

TBLRD and TBLWT instructions. These instructions can

update the TBLPTR in one of four ways based on the

table operation. These operations are shown in

Table 6-1. These operations on the TBLPTR only affect

the low-order 21 bits.

6.2.4 TABLE POINTER BOUNDARIES

TBLPTR is used in reads, writes and erases of the

Flash program memory.

When a TBLRD is executed, all 22 bits of the TBLPTR

determine which byte is read from program memory

into TABLAT.

When a TBLWT is executed, the seven LSbs of the

Table Pointer register (TBLPTR<6:0>) determine which

of the 64 program memory holding registers is written

to. When the timed write to program memory begins

(via the WR bit), the 12 MSbs of the TBLPTR

(TBLPTR<21:10>) determine which program memory

block of 1024 bytes is written to. For more detail, see

Section 6.5 “Writing to Flash Program Memory”.

When an erase of program memory is executed, the

12 MSbs of the Table Pointer register point to the

1024-byte block that will be erased. The Least

Significant bits are ignored.

Figure 6-3 describes the relevant boundaries of

TBLPTR based on Flash program memory operations.

TABLE 6-1: TABLE POINTER OPERATIONS WITH TBLRD AND TBLWT INSTRUCTIONS

FIGURE 6-3: TABLE POINTER BOUNDARIES BASED ON OPERATION

Example Operation on Table Pointer

TBLRD*

TBLWT* TBLPTR is not modified

TBLRD*+

TBLWT*+ TBLPTR is incremented after the read/write

TBLRD*-

TBLWT*- TBLPTR is decremented after the read/write

TBLRD+*

TBLWT+* TBLPTR is incremented before the read/write

21 16 15 87 0

ERASE: TBLPTR<20:10>

TABLE WRITE: TBLPTR<20:6>

TABLE READ: TBLPTR<21:0>

TBLPTRLTBLPTRH

TBLPTRU

PIC18F87J50 FAMILY

6.3 Reading the Flash Program

Memory

The TBLRD instruction is used to retrieve data from

program memory and places it into data RAM. Table

reads from program memory are performed one byte at

a time.

TBLPTR points to a byte address in program space.

Executing TBLRD places the byte pointed to into

TABLAT. In addition, TBLPTR can be modified

automatically for the next table read operation.

The internal program memory is typically organized by

words. The Least Significant bit of the address selects

between the high and low bytes of the word. Figure 6-4

shows the interface between the internal program

memory and the TABLAT.

FIGURE 6-4: READS FROM FLASH PROGRAM MEMORY

EXAMPLE 6-1: READING A FLASH PROGRAM MEMORY WORD

(Even Byte Address)

Program Memory

(Odd Byte Address)

TBLRD TABLAT

TBLPTR = xxxxx1

FETCH

Instruction Register

(IR) Read Register

TBLPTR = xxxxx0

MOVLW CODE_ADDR_UPPER ; Load TBLPTR with the base

MOVWF TBLPTRU ; address of the word

MOVLW CODE_ADDR_HIGH

MOVWF TBLPTRH

MOVLW CODE_ADDR_LOW

MOVWF TBLPTRL

READ_WORD

TBLRD*+ ; read into TABLAT and increment

MOVF TABLAT, W ; get data

MOVWF WORD_EVEN

TBLRD*+ ; read into TABLAT and increment

MOVF TABLAT, W ; get data

MOVWF WORD_ODD

PIC18F87J50 FAMILY

6.4 Erasing Flash Program Memory

The minimum erase block is 512 words or 1024 bytes.

Only through the use of an external programmer, or

through ICSP control, can larger blocks of program

memory be bulk erased. Word erase in the Flash array

is not supported.

When initiating an erase sequence from the micro-

controller itself, a block of 1024 bytes of program

memory is erased. The Most Significant 12 bits of the

TBLPTR<21:10> point to the block being erased.

TBLPTR<9:0> are ignored.

The EECON1 register commands the erase operation.

The WREN bit must be set to enable write operations.

The FREE bit is set to select an erase operation. For

protection, the write initiate sequence for EECON2

must be used.

A long write is necessary for erasing the internal Flash.

Instruction execution is halted while in a long write

cycle. The long write will be terminated by the internal

programming timer.

6.4.1 FLASH PROGRAM MEMORY

ERASE SEQUENCE

The sequence of events for erasing a block of internal

program memory location is:

1. Load Table Pointer register with address of row

being erased.

2. Set the WREN and FREE bits (EECON1<2,4>)

to enable the erase operation.

3. Disable interrupts.

4. Write 55h to EECON2.

5. Write 0AAh to EECON2.

6. Set the WR bit. This will begin the row erase

cycle.

7. The CPU will stall for duration of the erase for

TIW (see parameter D133A).

8. Re-enable interrupts.

EXAMPLE 6-2: ERASING A FLASH PROGRAM MEMORY ROW

MOVLW CODE_ADDR_UPPER ; load TBLPTR with the base

MOVWF TBLPTRU ; address of the memory block

MOVLW CODE_ADDR_HIGH

MOVWF TBLPTRH

MOVLW CODE_ADDR_LOW

MOVWF TBLPTRL

ERASE_ROW

BSF EECON1, WREN ; enable write to memory

BSF EECON1, FREE ; enable Row Erase operation

BCF INTCON, GIE ; disable interrupts

Required MOVLW 55h

Sequence MOVWF EECON2 ; write 55h

MOVLW 0AAh

MOVWF EECON2 ; write 0AAh

BSF EECON1, WR ; start erase (CPU stall)

BSF INTCON, GIE ; re-enable interrupts

PIC18F87J50 FAMILY

6.5 Writing to Flash Program Memory

The programming block is 32 words or 64 bytes.

Programming one word or two bytes at a time is also

supported.

Table writes are used internally to load the holding

registers needed to program the Flash memory. There

are 64 holding registers used by the table writes for

programming.

Since the Table Latch (TABLAT) is only a single byte, the

TBLWT instruction may need to be executed 64 times for

each programming operation (if WPROG = 0). All of the

table write operations will essentially be short writes

because only the holding registers are written. At the

end of updating the 64 holding registers, the EECON1

programming operation with a long write.

The long write is necessary for programming the inter-

nal Flash. Instruction execution is halted while in a long

write cycle. The long write will be terminated by the

internal programming timer.

The on-chip timer controls the write time. The

write/erase voltages are generated by an on-chip

charge pump, rated to operate over the voltage range

of the device.

FIGURE 6-5: TABLE WRITES TO FLASH PROGRAM MEMORY

6.5.1 FLASH PROGRAM MEMORY WRITE

SEQUENCE

The sequence of events for programming an internal

program memory location should be:

1. Read 1024 bytes into RAM.

2. Update data values in RAM as necessary.

3. Load Table Pointer register with address being

erased.

4. Execute the row erase procedure.

5. Load Table Pointer register with address of first

byte being written, minus 1.

6. Write the 64 bytes into the holding registers with

auto-increment.

7. Set the WREN bit (EECON1<2>) to enable byte

writes.

8. Disable interrupts.

9. Write 55h to EECON2.

10. Write 0AAh to EECON2.

11. Set the WR bit. This will begin the write cycle.

12. The CPU will stall for duration of the write for TIW

(see parameter D133A).

13. Re-enable interrupts.

14. Repeat steps 6 through 13 until all 1024 bytes

are written to program memory.

15. Verify the memory (table read).

An example of the required code is shown in

Example 6-3 on the following page.

Note 1: Unlike previous PIC® devices, members

of the PIC18F87J10 family do not reset

the holding registers after a write occurs.

The holding registers must be cleared or

overwritten before a programming

sequence.

2: To maintain the endurance of the program

memory cells, each Flash byte should not

be programmed more than one time

between erase operations. Before

attempting to modify the contents of the

target cell a second time, a row erase of

the target row, or a bulk erase of the entire

memory, must be performed.

TABLAT

TBLPTR = xxxx3FTBLPTR = xxxxx1TBLPTR = xxxxx0

Write Register

TBLPTR = xxxxx2

Program Memory

Holding Register Holding Register Holding Register Holding Register

88 8 8

Note: Before setting the WR bit, the Table

Pointer address needs to be within the

intended address range of the 64 bytes in

the holding register.

PIC18F87J50 FAMILY

EXAMPLE 6-3: WRITING TO FLASH PROGRAM MEMORY

MOVLW CODE_ADDR_UPPER ; Load TBLPTR with the base address

MOVWF TBLPTRU ; of the memory block, minus 1

MOVLW CODE_ADDR_HIGH

MOVWF TBLPTRH

MOVLW CODE_ADDR_LOW

MOVWF TBLPTRL

ERASE_BLOCK

BSF EECON1, WREN ; enable write to memory

BSF EECON1, FREE ; enable Row Erase operation

BCF INTCON, GIE ; disable interrupts

MOVLW 55h

MOVWF EECON2 ; write 55h

MOVLW 0AAh

MOVWF EECON2 ; write 0AAh

BSF EECON1, WR ; start erase (CPU stall)

BSF INTCON, GIE ; re-enable interrupts

MOVLW D'16'

MOVWF WRITE_COUNTER ; Need to write 16 blocks of 64 to write

; one erase block of 1024

RESTART_BUFFER

MOVLW D'64'

MOVWF COUNTER

MOVLW BUFFER_ADDR_HIGH ; point to buffer

MOVWF FSR0H

MOVLW BUFFER_ADDR_LOW

MOVWF FSR0L

FILL_BUFFER

... ; read the new data from I2C, SPI,

; PSP, USART, etc.

WRITE_BUFFER

MOVLW D’64 ; number of bytes in holding register

MOVWF COUNTER

WRITE_BYTE_TO_HREGS

MOVFF POSTINC0, WREG ; get low byte of buffer data

MOVWF TABLAT ; present data to table latch

TBLWT+* ; write data, perform a short write

; to internal TBLWT holding register.

DECFSZ COUNTER ; loop until buffers are full

BRA WRITE_BYTE_TO_HREGS

PROGRAM_MEMORY

BSF EECON1, WREN ; enable write to memory

BCF INTCON, GIE ; disable interrupts

MOVLW 55h

Required MOVWF EECON2 ; write 55h

Sequence MOVLW 0AAh

MOVWF EECON2 ; write 0AAh

BSF EECON1, WR ; start program (CPU stall)

BSF INTCON, GIE ; re-enable interrupts

BCF EECON1, WREN ; disable write to memory

DECFSZ WRITE_COUNTER ; done with one write cycle

BRA RESTART_BUFFER ; if not done replacing the erase block

PIC18F87J50 FAMILY

6.5.2 FLASH PROGRAM MEMORY WRITE

SEQUENCE (WORD PRORAMMING).

The PIC18F87J10 family of devices have a feature that

allows programming a single word (two bytes). This

feature is enabled when the WPROG bit is set. If the

memory location is already erased, the following

sequence is required to enable this feature:

1. Load the Table Pointer register with the address

of the data to be written. (It must be an even

address.)

2. Write the 2 bytes into the holding registers by

performing table writes. (Do not post-increment

on the second table write.)

3. Set the WREN bit (EECON1<2>) to enable

writes and the WPROG bit (EECON1<5>) to

select Word Write mode.

4. Disable interrupts.

5. Write 55h to EECON2.

6. Write AAh to EECON2.

7. Set the WR bit. This will begin the write cycle.

8. The CPU will stall for duration of the write for TIW

(see parameter D133A).

9. Re-enable interrupts.

EXAMPLE 6-4: SINGLE WORD WRITE TO FLASH PROGRAM MEMORY

MOVLW CODE_ADDR_UPPER ; Load TBLPTR with the base address

MOVWF TBLPTRU

MOVLW CODE_ADDR_HIGH

MOVWF TBLPTRH

MOVLW CODE_ADDR_LOW ; The table pointer must be loaded with an even

address

MOVWF TBLPTRL

MOVLW DATA0 ; LSB of word to be written

MOVWF TABLAT

TBLWT*+

MOVLW DATA1 ; MSB of word to be written

MOVWF TABLAT

TBLWT* ; The last table write must not increment the table

pointer! The table pointer needs to point to the

MSB before starting the write operation.

PROGRAM_MEMORY

BSF EECON1, WPROG ; enable single word write

BSF EECON1, WREN ; enable write to memory

BCF INTCON, GIE ; disable interrupts

MOVLW 55h

Required MOVWF EECON2 ; write 55h

Sequence MOVLW 0AAh

MOVWF EECON2 ; write 0AAh

BSF EECON1, WR ; start program (CPU stall)

BSF INTCON, GIE ; re-enable interrupts

BCF EECON1, WPROG ; disable single word write

BCF EECON1, WREN ; disable write to memory

PIC18F87J50 FAMILY

6.5.3 WRITE VERIFY

Depending on the application, good programming

practice may dictate that the value written to the

memory should be verified against the original value.

This should be used in applications where excessive

writes can stress bits near the specification limit.

6.5.4 UNEXPECTED TERMINATION OF

WRITE OPERATION

If a write is terminated by an unplanned event, such as

loss of power or an unexpected Reset, the memory

location just programmed should be verified and repro-

grammed if needed. If the write operation is interrupted

by a MCLR Reset or a WDT time-out Reset during

normal operation, the user can check the WRERR bit

and rewrite the location(s) as needed.

6.6 Flash Program Operation During

Code Protection

See Section 25.6 “Program Verification and Code

Protection” for details on code protection of Flash

program memory.

TABLE 6-2: REGISTERS ASSOCIATED WITH PROGRAM FLASH MEMORY

Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Reset

Values on

Page:

TBLPTRU —— bit 21 Program Memory Table Pointer Upper Byte (TBLPTR<20:16>) 61

TBPLTRH Program Memory Table Pointer High Byte (TBLPTR<15:8>) 61

TBLPTRL Program Memory Table Pointer Low Byte (TBLPTR<7:0>) 61

TABLAT Program Memory Table Latch 61

INTCON GIE/GIEH PEIE/GIEL TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 61

EECON2 Program Memory Control Register 2 (not a physical register) 63

EECON1 —— WPROG FREE WRERR WREN WR —63

Legend: — = unimplemented, read as ‘0’. Shaded cells are not used during Flash program memory access.

PIC18F87J50 FAMILY

7.0 EXTERNAL MEMORY BUS

The External Memory Bus (EMB) allows the device to

access external memory devices (such as Flash,

EPROM, SRAM, etc.) as program or data memory. It

supports both 8 and 16-Bit Data Width modes and

three address widths of up to 20 bits.

The bus is implemented with 28 pins, multiplexed

across four I/O ports. Three ports (PORTD, PORTE

and PORTH) are multiplexed with the address/data bus

for a total of 20 available lines, while PORTJ is

multiplexed with the bus control signals.

A list of the pins and their functions is provided in

Table 7-1.

TABLE 7-1: PIC18F87J50 FAMILY EXTERNAL BUS – I/O PORT FUNCTIONS

Note: The External Memory Bus is not

implemented on 64-pin devices.

Name Port Bit External Memory Bus Function

RD0/AD0 PORTD 0 Address bit 0 or Data bit 0

RD1/AD1 PORTD 1 Address bit 1 or Data bit 1

RD2/AD2 PORTD 2 Address bit 2 or Data bit 2

RD3/AD3 PORTD 3 Address bit 3 or Data bit 3

RD4/AD4 PORTD 4 Address bit 4 or Data bit 4

RD5/AD5 PORTD 5 Address bit 5 or Data bit 5

RD6/AD6 PORTD 6 Address bit 6 or Data bit 6

RD7/AD7 PORTD 7 Address bit 7 or Data bit 7

RE0/AD8 PORTE 0 Address bit 8 or Data bit 8

RE1/AD9 PORTE 1 Address bit 9 or Data bit 9

RE2/AD10 PORTE 2 Address bit 10 or Data bit 10

RE3/AD11 PORTE 3 Address bit 11 or Data bit 11

RE4/AD12 PORTE 4 Address bit 12 or Data bit 12

RE5/AD13 PORTE 5 Address bit 13 or Data bit 13

RE6/AD14 PORTE 6 Address bit 14 or Data bit 14

RE7/AD15 PORTE 7 Address bit 15 or Data bit 15

RH0/A16 PORTH 0 Address bit 16

RH1/A17 PORTH 1 Address bit 17

RH2/A18 PORTH 2 Address bit 18

RH3/A19 PORTH 3 Address bit 19

RJ0/ALE PORTJ 0 Address Latch Enable (ALE) Control pin

RJ1/OE PORTJ 1 Output Enable (OE) Control pin

RJ2/WRL PORTJ 2 Write Low (WRL) Control pin

RJ3/WRH PORTJ 3 Write High (WRH) Control pin

RJ4/BA0 PORTJ 4 Byte Address bit 0 (BA0)

RJ5/CE PORTJ 5 Chip Enable (CE) Control pin

RJ6/LB PORTJ 6 Lower Byte Enable (LB) Control pin

RJ7/UB PORTJ 7 Upper Byte Enable (UB) Control pin

Note: For the sake of clarity, only I/O port and external bus assignments are shown here. One or more additional

multiplexed features may be available on some pins.

PIC18F87J50 FAMILY

7.1 External Memory Bus Control

The operation of the interface is controlled by the

MEMCON register (Register 7-1). This register is

available in all program memory operating modes

except Microcontroller mode. In this mode, the register

is disabled and cannot be written to.

The EBDIS bit (MEMCON<7>) controls the operation

of the bus and related port functions. Clearing EBDIS

enables the interface and disables the I/O functions of

the ports, as well as any other functions multiplexed to

those pins. Setting the bit enables the I/O ports and

other functions, but allows the interface to override

everything else on the pins when an external memory

operation is required. By default, the external bus is

always enabled and disables all other I/O.

The operation of the EBDIS bit is also influenced by the

program memory mode being used. This is discussed

in more detail in Section 7.5 “Program Memory

Modes and the External Memory Bus”.

The WAIT bits allow for the addition of wait states to

external memory operations. The use of these bits is

discussed in Section 7.3 “Wait States”.

The WM bits select the particular operating mode used

when the bus is operating in 16-Bit Data Width mode.

These are discussed in more detail in Section 7.6

“16-Bit Data Width Modes”. These bits have no effect

when an 8-Bit Data Width mode is selected.

The MEMCON register (see Register 7-1) shares the

same memory space as the PR2 register and can be

alternately selected based on the designation of the

ADSHR bit in the WDTCON register (see

R/W-0 U-0 R/W-0 R/W-0 U-0 U-0 R/W-0 R/W-0

EBDIS —WAIT1WAIT0——WM1WM0

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 EBDIS: External Bus Disable bit

1 = External bus enabled when microcontroller accesses external memory; otherwise, all external bus

drivers are mapped as I/O ports

0 = External bus always enabled, I/O ports are disabled

bit 6 Unimplemented: Read as ‘0’

bit 5-4 WAIT1:WAIT0: Table Reads and Writes Bus Cycle Wait Count bits

11 = Table reads and writes will wait 0 TCY

10 = Table reads and writes will wait 1 TCY

01 = Table reads and writes will wait 2 TCY

00 = Table reads and writes will wait 3 TCY

bit 3-2 Unimplemented: Read as ‘0’

bit 1-0 WM1:WM0: TBLWT Operation with 16-Bit Data Bus Width Select bits

1x = Word Write mode: TABLAT word output, WRH active when TABLAT is written

01 = Byte Select mode: TABLAT data copied on both MSB and LSB, WRH and (UB or LB) will activate

00 = Byte Write mode: TABLAT data copied on both MSB and LSB, WRH or WRL will activate

PIC18F87J50 FAMILY

7.2 Address and Data Width

The PIC18F87J10 family of devices can be indepen-

dently configured for different address and data widths

on the same memory bus. Both address and data width

are set by Configuration bits in the CONFIG3L register.

As Configuration bits, this means that these options

can only be configured by programming the device and

are not controllable in software.

The BW bit selects an 8-bit or 16-bit data bus width.

Setting this bit (default) selects a data width of 16 bits.

The EMB1:EMB0 bits determine both the program

memory operating mode and the address bus width.

The available options are 20-bit, 16-bit and 12-bit, as

well as Microcontroller mode (external bus disabled).

Selecting a 16-bit or 12-bit width makes a correspond-

ing number of high-order lines available for I/O

functions. These pins are no longer affected by the

setting of the EBDIS bit. For example, selecting a

16-Bit Addressing mode (EMB1:EMB0 = 01) disables

A19:A16 and allows PORTH<3:0> to function without

interruptions from the bus. Using the smaller address

widths allows users to tailor the memory bus to the size

of the external memory space for a particular design

while freeing up pins for dedicated I/O operation.

Because the EMB bits have the effect of disabling pins

for memory bus operations, it is important to always

select an address width at least equal to the data width.

If a 12-bit address width is used with a 16-bit data

width, the upper four bits of data will not be available on

the bus.

All combinations of address and data widths require

multiplexing of address and data information on the

same lines. The address and data multiplexing, as well

as I/O ports made available by the use of smaller

address widths, are summarized in Table 7-2.

7.2.1 ADDRESS SHIFTING ON THE

EXTERNAL BUS

By default, the address presented on the external bus

is the value of the PC. In practical terms, this means

that addresses in the external memory device below

the top of on-chip memory are unavailable to the micro-

controller. To access these physical locations, the glue

logic between the microcontroller and the external

memory must somehow translate addresses.

To simplify the interface, the external bus offers an

extension of Extended Microcontroller mode that

automatically performs address shifting. This feature is

controlled by the EASHFT Configuration bit. Setting

this bit offsets addresses on the bus by the size of the

microcontroller’s on-chip program memory and sets

the bottom address at 0000h. This allows the device to

use the entire range of physical addresses of the

external memory.

7.2.2 21-BIT ADDRESSING

As an extension of 20-bit address width operation, the

External Memory Bus can also fully address a 2-Mbyte

memory space. This is done by using the Bus Address

bit 0 (BA0) control line as the Least Significant bit of the

address. The UB and LB control signals may also be

used with certain memory devices to select the upper

and lower bytes within a 16-bit wide data word.

This addressing mode is available in both 8-Bit and

certain 16-Bit Data Width modes. Additional details are

provided in Section 7.6.3 “16-Bit Byte Select Mode”

and Section 7.7 “8-Bit Data Width Mode”.

TABLE 7-2: ADDRESS AND DATA LINES FOR DIFFERENT ADDRESS AND DATA WIDTHS

Data Width Address Width

Multiplexed Data and

Address Lines (and

Corresponding Ports)

Address Only

Lines (and

Corresponding Ports)

Ports Available

for I/O

8-bit

12-bit

AD7:AD0

(PORTD<7:0>)

AD11:AD8

(PORTE<3:0>)

PORTE<7:4>,

All of PORTH

16-bit AD15:AD8

(PORTE<7:0>) All of PORTH

20-bit

A19:A16, AD15:AD8

(PORTH<3:0>,

PORTE<7:0>)

—

16-bit

16-bit AD15:AD0

(PORTD<7:0>,

PORTE<7:0>)

— All of PORTH

20-bit A19:A16

(PORTH<3:0>) —

PIC18F87J50 FAMILY

7.3 Wait States

While it may be assumed that external memory devices

will operate at the microcontroller clock rate, this is

often not the case. In fact, many devices require longer

times to write or retrieve data than the time allowed by

the execution of table read or table write operations.

To compensate for this, the External Memory Bus can

be configured to add a fixed delay to each table opera-

tion using the bus. Wait states are enabled by setting

the WAIT Configuration bit. When enabled, the amount

of delay is set by the WAIT1:WAIT0 bits

(MEMCON<5:4>). The delay is based on multiples of

microcontroller instruction cycle time and are added

following the instruction cycle when the table operation

is executed. The range is from no delay to 3 TCY

(default value).

7.4 Port Pin Weak Pull-ups

With the exception of the upper address lines,

A19:A16, the pins associated with the External Memory

Bus are equipped with weak pull-ups. The pull-ups are

controlled by the upper three bits of the PORTG

REPU and RJPU and control pull-ups on PORTD,

PORTE and PORTJ, respectively. Setting one of these

bits enables the corresponding pull-ups for that port. All

pull-ups are disabled by default on all device Resets.

In Extended Microcontroller mode, the port pull-ups

can be useful in preserving the memory state on the

external bus while the bus is temporarily disabled

(EBDIS = ‘1’).

7.5 Program Memory Modes and the

External Memory Bus

The PIC18F87J10 family of devices is capable of

operating in one of two program memory modes, using

combinations of on-chip and external program memory.

The functions of the multiplexed port pins depend on

the program memory mode selected, as well as the

setting of the EBDIS bit.

In Microcontroller Mode, the bus is not active and the

pins have their port functions only. Writes to the

MEMCOM register are not permitted. The Reset value

of EBDIS (‘0’) is ignored and EMB pins behave as I/O

ports.

In Extended Microcontroller Mode, the external

program memory bus shares I/O port functions on the

pins. When the device is fetching or doing table

read/table write operations on the external program

memory space, the pins will have the external bus

function.

If the device is fetching and accessing internal program

memory locations only, the EBDIS control bit will

change the pins from external memory to I/O port

functions. When EBDIS = 0, the pins function as the

external bus. When EBDIS = 1, the pins function as I/O

ports.

If the device fetches or accesses external memory

while EBDIS = 1, the pins will switch to external bus. If

the EBDIS bit is set by a program executing from exter-

nal memory, the action of setting the bit will be delayed

until the program branches into the internal memory. At

that time, the pins will change from external bus to I/O

ports.

If the device is executing out of internal memory when

EBDIS = 0, the memory bus address/data and control

pins will not be active. They will go to a state where the

active address/data pins are tri-state; the CE, OE,

WRH, WRL, UB and LB signals are ‘1’ and ALE and

BA0 are ‘0’. Note that only those pins associated with

the current address width are forced to tri-state; the

other pins continue to function as I/O. In the case of

16-bit address width, for example, only AD<15:0>

(PORTD and PORTE) are affected; A19:A16

(PORTH<3:0>) continue to function as I/O.

In all external memory modes, the bus takes priority

over any other peripherals that may share pins with it.

This includes the Parallel Master Port and serial

communication modules which would otherwise take

priority over the I/O port.

7.6 16-Bit Data Width Modes

In 16-Bit Data Width mode, the external memory

interface can be connected to external memories in

three different configurations:

• 16-Bit Byte Write

• 16-Bit Word Write

• 16-Bit Byte Select

The configuration to be used is determined by the

WM1:WM0 bits in the MEMCON register

(MEMCON<1:0>). These three different configurations

allow the designer maximum flexibility in using both

8-bit and 16-bit devices with 16-bit data.

For all 16-bit modes, the Address Latch Enable (ALE)

pin indicates that the address bits, AD<15:0>, are avail-

able on the external memory interface bus. Following

the address latch, the Output Enable signal (OE) will

enable both bytes of program memory at once to form

a 16-bit instruction word. The Chip Enable signal (CE)

is active at any time that the microcontroller accesses

external memory, whether reading or writing; it is

inactive (asserted high) whenever the device is in

Sleep mode.

In Byte Select mode, JEDEC standard Flash memories

will require BA0 for the byte address line and one I/O

line to select between Byte and Word mode. The other

16-bit modes do not need BA0. JEDEC standard static

RAM memories will use the UB or LB signals for byte

selection.

PIC18F87J50 FAMILY

7.6.1 16-BIT BYTE WRITE MODE

Figure 7-1 shows an example of 16-Bit Byte Write

mode for PIC18F87J10 family devices. This mode is

used for two separate 8-bit memories connected for

16-bit operation. This generally includes basic EPROM

and Flash devices. It allows table writes to byte-wide

external memories.

During a TBLWT instruction cycle, the TABLAT data is

presented on the upper and lower bytes of the

AD15:AD0 bus. The appropriate WRH or WRL control

line is strobed on the LSb of the TBLPTR.

FIGURE 7-1: 16-BIT BYTE WRITE MODE EXAMPLE

AD<7:0>

A<19:16>(1)

ALE

D<15:8>

373 A<x:0>

D<7:0>

A<19:0> A<x:0>

D<7:0>

373

WRH

OE OE

WR(2) WR(2)

CE CE

Note 1: Upper order address lines are used only for 20-bit address widths.

2: This signal only applies to table writes. See Section 6.1 “Table Reads and Table Writes”.

WRL

D<7:0>

(LSB)

(MSB)

PIC18F87J50

D<7:0>

AD<15:8>

Address Bus

Data Bus

Control Lines

PIC18F87J50 FAMILY

7.6.2 16-BIT WORD WRITE MODE

Figure 7-2 shows an example of 16-Bit Word Write

mode for PIC18F87J10 family devices. This mode is

used for word-wide memories which include some of

the EPROM and Flash-type memories. This mode

allows opcode fetches and table reads from all forms of

16-bit memory and table writes to any type of

word-wide external memories. This method makes a

distinction between TBLWT cycles to even or odd

addresses.

During a TBLWT cycle to an even address

(TBLPTR<0> = 0), the TABLAT data is transferred to a

holding latch and the external address data bus is

tri-stated for the data portion of the bus cycle. No write

signals are activated.

During a TBLWT cycle to an odd address

(TBLPTR<0> = 1), the TABLAT data is presented on

the upper byte of the AD15:AD0 bus. The contents of

the holding latch are presented on the lower byte of the

AD15:AD0 bus.

The WRH signal is strobed for each write cycle; the

WRL pin is unused. The signal on the BA0 pin indicates

the LSb of the TBLPTR, but it is left unconnected.

Instead, the UB and LB signals are active to select both

bytes. The obvious limitation to this method is that the

table write must be done in pairs on a specific word

boundary to correctly write a word location.

FIGURE 7-2: 16-BIT WORD WRITE MODE EXAMPLE

AD<7:0>

PIC18F87J50

AD<15:8>

ALE

373 A<20:1>

373

WRH

A<19:16>(1)

A<x:0>

D<15:0>

OE WR(2)

D<15:0>

JEDEC Word

EPROM Memory

Address Bus

Data Bus

Control Lines

Note 1: Upper order address lines are used only for 20-bit address widths.

2: This signal only applies to table writes. See Section 6.1 “Table Reads and Table Writes”.

PIC18F87J50 FAMILY

7.6.3 16-BIT BYTE SELECT MODE

Figure 7-3 shows an example of 16-Bit Byte Select

mode. This mode allows table write operations to

word-wide external memories with byte selection

capability. This generally includes both word-wide

Flash and SRAM devices.

During a TBLWT cycle, the TABLAT data is presented

on the upper and lower byte of the AD15:AD0 bus. The

WRH signal is strobed for each write cycle; the WRL

pin is not used. The BA0 or UB/LB signals are used to

select the byte to be written, based on the Least

Significant bit of the TBLPTR register.

Flash and SRAM devices use different control signal

combinations to implement Byte Select mode. JEDEC

standard Flash memories require that a controller I/O

port pin be connected to the memory’s BYTE/WORD

pin to provide the select signal. They also use the BA0

signal from the controller as a byte address. JEDEC

standard static RAM memories, on the other hand, use

the UB or LB signals to select the byte.

FIGURE 7-3: 16-BIT BYTE SELECT MODE EXAMPLE

AD<7:0>

PIC18F87J50

AD<15:8>

ALE

373 A<20:1>

373

WRH

A<19:16>(2)

WRL

BA0

JEDEC Word

A<x:1>

D<15:0>

A<20:1>

D<15:0>

I/O

OE WR(1)

BYTE/WORD

FLASH Memory

JEDEC Word

A<x:1>

D<15:0>

OE WR(1)

SRAM Memory

138(3)

Address Bus

Data Bus

Control Lines

Note 1: This signal only applies to table writes. See Section 6.1 “Table Reads and Table Writes”.

2: Upper order address lines are used only for 20-bit address width.

3: Demultiplexing is only required when multiple memory devices are accessed.

PIC18F87J50 FAMILY

7.6.4 16-BIT MODE TIMING

The presentation of control signals on the External

Memory Bus is different for the various operating

modes. Typical signal timing diagrams are shown in

Figure 7-4 and Figure 7-5.

FIGURE 7-4: EXTERNAL MEMORY BUS TIMING FOR TBLRD (EXTENDED

MICROCONTROLLER MODE)

FIGURE 7-5: EXTERNAL MEMORY BUS TIMING FOR SLEEP (EXTENDED

MICROCONTROLLER MODE)

Q2Q1 Q3 Q4 Q2Q1 Q3 Q4 Q2Q1 Q3 Q4

A<19:16>

ALE

AD<15:0>

Opcode Fetch Opcode Fetch Opcode Fetch

TBLRD *

TBLRD Cycle 1

ADDLW 55h

from 000100h

Q2Q1 Q3 Q4

0Ch

CF33h

TBLRD 92h

from 199E67h

9256h

from 000104h

Memory

Cycle

Instruction

Execution INST(PC – 2) TBLRD Cycle 2

MOVLW 55h

from 000102h

MOVLW

Q2Q1 Q3 Q4 Q2Q1 Q3 Q4

A<19:16>

ALE

3AAAh

AD<15:0>

00h 00h

Opcode Fetch Opcode Fetch

SLEEP

from 007554h

Bus Inactive

0003h

3AABh

0E55h

Memory

Cycle

Instruction

Execution INST(PC – 2)

Sleep Mode,

MOVLW 55h

from 007556h

PIC18F87J50 FAMILY

7.7 8-Bit Data Width Mode

In 8-Bit Data Width mode, the External Memory Bus

operates only in Multiplexed mode; that is, data shares

the 8 Least Significant bits of the address bus.

Figure 7-6 shows an example of 8-Bit Multiplexed

mode for 80-pin devices. This mode is used for a single

8-bit memory connected for 16-bit operation. The

instructions will be fetched as two 8-bit bytes on a

shared data/address bus. The two bytes are sequen-

tially fetched within one instruction cycle (TCY).

Therefore, the designer must choose external memory

devices according to timing calculations based on

1/2 TCY (2 times the instruction rate). For proper mem-

ory speed selection, glue logic propagation delay times

must be considered, along with setup and hold times.

The Address Latch Enable (ALE) pin indicates that the

address bits, AD<15:0>, are available on the external

memory interface bus. The Output Enable signal (OE)

will enable one byte of program memory for a portion of

the instruction cycle, then BA0 will change and the

second byte will be enabled to form the 16-bit instruc-

tion word. The Least Significant bit of the address, BA0,

must be connected to the memory devices in this

mode. The Chip Enable signal (CE) is active at any

time that the microcontroller accesses external

memory, whether reading or writing. It is inactive

(asserted high) whenever the device is in Sleep mode.

This generally includes basic EPROM and Flash

devices. It allows table writes to byte-wide external

memories.

FIGURE 7-6: 8-BIT MULTIPLEXED MODE EXAMPLE

AD<7:0>

A<19:16>(1)

ALE D<15:8>

373 A<19:0> A<x:1>

D<7:0>

OE WR(2)

Note 1: Upper order address bits are only used for 20-bit address width. The upper AD byte is used for all

address widths except 8-bit.

2: This signal only applies to table writes. See Section 6.1 “Table Reads and Table Writes”.

WRL

D<7:0>

PIC18F87J50

AD<15:8>(1)

Address Bus

Data Bus

Control Lines

BA0

PIC18F87J50 FAMILY

7.7.1 8-BIT MODE TIMING

The presentation of control signals on the External

Memory Bus is different for the various operating

modes. Typical signal timing diagrams are shown in

Figure 7-7 and Figure 7-8.

FIGURE 7-7: EXTERNAL MEMORY BUS TIMING FOR TBLRD (EXTENDED

MICROCONTROLLER MODE)

FIGURE 7-8: EXTERNAL MEMORY BUS TIMING FOR SLEEP (EXTENDED

MICROCONTROLLER MODE)

Q2Q1 Q3 Q4 Q2Q1 Q3 Q4 Q2Q1 Q3 Q4

A<19:16>

ALE

AD<7:0>

Opcode Fetch Opcode Fetch Opcode Fetch

TBLRD *

TBLRD Cycle 1

ADDLW 55h

from 000100h

Q2Q1 Q3 Q4

0Ch

33h

TBLRD 92h

from 199E67h

92h

from 000104h

Memory

Cycle

Instruction

Execution INST(PC – 2) TBLRD Cycle 2

MOVLW 55h

from 000102h

MOVLW

AD<15:8> CFh

Q2Q1 Q3 Q4 Q2Q1 Q3 Q4

A<19:16>

ALE

AAh

AD<7:0>

00h 00h

Opcode Fetch Opcode Fetch

SLEEP

from 007554h

Bus Inactive

00h ABh 55h

Memory

Cycle

Instruction

Execution INST(PC – 2)

Sleep Mode,

MOVLW 55h

from 007556h

AD<15:8> 3Ah 3Ah

03h 0Eh

BA0

PIC18F87J50 FAMILY

7.8 Operation in Power-Managed

Modes

In alternate, power-managed Run modes, the external

bus continues to operate normally. If a clock source

with a lower speed is selected, bus operations will run

at that speed. In these cases, excessive access times

for the external memory may result if wait states have

been enabled and added to external memory opera-

tions. If operations in a lower power Run mode are

anticipated, users should provide in their applications

for adjusting memory access times at the lower clock

speeds.

In Sleep and Idle modes, the microcontroller core does

not need to access data; bus operations are

suspended. The state of the external bus is frozen, with

the address/data pins and most of the control pins hold-

ing at the same state they were in when the mode was

invoked. The only potential changes are the CE, LB

and UB pins, which are held at logic high.

PIC18F87J50 FAMILY

NOTES:

PIC18F87J50 FAMILY

8.0 8 x 8 HARDWARE MULTIPLIER

8.1 Introduction

All PIC18 devices include an 8 x 8 hardware multiplier

as part of the ALU. The multiplier performs an unsigned

operation and yields a 16-bit result that is stored in the

product register pair, PRODH:PRODL. The multiplier’s

operation does not affect any flags in the STATUS

Making multiplication a hardware operation allows it to

be completed in a single instruction cycle. This has the

advantages of higher computational throughput and

reduced code size for multiplication algorithms and

allows the PIC18 devices to be used in many applica-

tions previously reserved for digital signal processors.

A comparison of various hardware and software

multiply operations, along with the savings in memory

and execution time, is shown in Table 8-1.

8.2 Operation

Example 8-1 shows the instruction sequence for an 8 x 8

unsigned multiplication. Only one instruction is required

when one of the arguments is already loaded in the

WREG register.

Example 8-2 shows the sequence to do an 8 x 8 signed

multiplication. To account for the sign bits of the argu-

ments, each argument’s Most Significant bit (MSb) is

tested and the appropriate subtractions are done.

EXAMPLE 8-1: 8 x 8 UNSIGNED

MULTIPLY ROUTINE

EXAMPLE 8-2: 8 x 8 SIGNED MULTIPLY

ROUTINE

TABLE 8-1: PERFORMANCE COMPARISON FOR VARIOUS MULTIPLY OPERATIONS

MOVF ARG1, W ;

MULWF ARG2 ; ARG1 * ARG2 ->

; PRODH:PRODL

MOVF ARG1, W

MULWF ARG2 ; ARG1 * ARG2 ->

; PRODH:PRODL

BTFSC ARG2, SB ; Test Sign Bit

SUBWF PRODH, F ; PRODH = PRODH

; - ARG1

MOVF ARG2, W

BTFSC ARG1, SB ; Test Sign Bit

SUBWF PRODH, F ; PRODH = PRODH

; - ARG2

Routine Multiply Method

Program

Memory

(Words)

Cycles

(Max)

Time

@ 48 MHz @ 10 MHz @ 4 MHz

8 x 8 unsigned Without hardware multiply 13 69 5.7 μs27.6 μs69 μs

Hardware multiply 1 1 83.3 ns 400 ns 1 μs

8 x 8 signed Without hardware multiply 33 91 7.5 μs36.4 μs91 μs

Hardware multiply 6 6 500 ns 2.4 μs6 μs

16 x 16 unsigned Without hardware multiply 21 242 20.1 μs96.8 μs242 μs

Hardware multiply 28 28 2.3 μs 11.2 μs28 μs

16 x 16 signed Without hardware multiply 52 254 21.6 μs 102.6 μs254 μs

Hardware multiply 35 40 3.3 μs16.0 μs40 μs

PIC18F87J50 FAMILY

Example 8-3 shows the sequence to do a 16 x 16

unsigned multiplication. Equation 8-1 shows the

algorithm that is used. The 32-bit result is stored in four

registers (RES3:RES0).

EQUATION 8-1: 16 x 16 UNSIGNED

MULTIPLICATION

ALGORITHM

EXAMPLE 8-3: 16 x 16 UNSIGNED

MULTIPLY ROUTINE

Example 8-4 shows the sequence to do a 16 x 16

signed multiply. Equation 8-2 shows the algorithm

used. The 32-bit result is stored in four registers

(RES3:RES0). To account for the sign bits of the

arguments, the MSb for each argument pair is tested

and the appropriate subtractions are done.

EQUATION 8-2: 16 x 16 SIGNED

MULTIPLICATION

ALGORITHM

EXAMPLE 8-4: 16 x 16 SIGNED

MULTIPLY ROUTINE

RES3:RES0 = ARG1H:ARG1L • ARG2H:ARG2L

= (ARG1H • ARG2H • 216) +

(ARG1H • ARG2L • 28) +

(ARG1L • ARG2H • 28) +

(ARG1L • ARG2L)

MOVF ARG1L, W

MULWF ARG2L ; ARG1L * ARG2L->

; PRODH:PRODL

MOVFF PRODH, RES1 ;

MOVFF PRODL, RES0 ;

;

MOVF ARG1H, W

MULWF ARG2H ; ARG1H * ARG2H->

; PRODH:PRODL

MOVFF PRODH, RES3 ;

MOVFF PRODL, RES2 ;

;

MOVF ARG1L, W

MULWF ARG2H ; ARG1L * ARG2H->

; PRODH:PRODL

MOVF PRODL, W ;

ADDWF RES1, F ; Add cross

MOVF PRODH, W ; products

ADDWFC RES2, F ;

CLRF WREG ;

ADDWFC RES3, F ;

;

MOVF ARG1H, W ;

MULWF ARG2L ; ARG1H * ARG2L->

; PRODH:PRODL

MOVF PRODL, W ;

ADDWF RES1, F ; Add cross

MOVF PRODH, W ; products

ADDWFC RES2, F ;

CLRF WREG ;

ADDWFC RES3, F ;

RES3:RES0 = ARG1H:ARG1L • ARG2H:ARG2L

= (ARG1H • ARG2H • 216) +

(ARG1H • ARG2L • 28) +

(ARG1L • ARG2H • 28) +

(ARG1L • ARG2L) +

(-1 • ARG2H<7> • ARG1H:ARG1L • 216) +

(-1 • ARG1H<7> • ARG2H:ARG2L • 216)

MOVF ARG1L, W

MULWF ARG2L ; ARG1L * ARG2L ->

; PRODH:PRODL

MOVFF PRODH, RES1 ;

MOVFF PRODL, RES0 ;

;

MOVF ARG1H, W

MULWF ARG2H ; ARG1H * ARG2H ->

; PRODH:PRODL

MOVFF PRODH, RES3 ;

MOVFF PRODL, RES2 ;

;

MOVF ARG1L, W

MULWF ARG2H ; ARG1L * ARG2H ->

; PRODH:PRODL

MOVF PRODL, W ;

ADDWF RES1, F ; Add cross

MOVF PRODH, W ; products

ADDWFC RES2, F ;

CLRF WREG ;

ADDWFC RES3, F ;

;

MOVF ARG1H, W ;

MULWF ARG2L ; ARG1H * ARG2L ->

; PRODH:PRODL

MOVF PRODL, W ;

ADDWF RES1, F ; Add cross

MOVF PRODH, W ; products

ADDWFC RES2, F ;

CLRF WREG ;

ADDWFC RES3, F ;

;

BTFSS ARG2H, 7 ; ARG2H:ARG2L neg?

BRA SIGN_ARG1 ; no, check ARG1

MOVF ARG1L, W ;

SUBWF RES2 ;

MOVF ARG1H, W ;

SUBWFB RES3

;

SIGN_ARG1

BTFSS ARG1H, 7 ; ARG1H:ARG1L neg?

BRA CONT_CODE ; no, done

MOVF ARG2L, W ;

SUBWF RES2 ;

MOVF ARG2H, W ;

SUBWFB RES3

;

CONT_CODE

PIC18F87J50 FAMILY

9.0 INTERRUPTS

Members of the PIC18F87J10 family of devices have

multiple interrupt sources and an interrupt priority

feature that allows most interrupt sources to be

assigned a high-priority level or a low-priority level. The

high-priority interrupt vector is at 0008h and the

low-priority interrupt vector is at 0018h. High-priority

interrupt events will interrupt any low-priority interrupts

that may be in progress.

There are thirteen registers which are used to control

interrupt operation. These registers are:

• RCON

•INTCON

• INTCON2

• INTCON3

• PIR1, PIR2, PIR3

• PIE1, PIE2, PIE3

• IPR1, IPR2, IPR3

It is recommended that the Microchip header files

supplied with MPLAB® IDE be used for the symbolic bit

names in these registers. This allows the

assembler/compiler to automatically take care of the

placement of these bits within the specified register.

In general, interrupt sources have three bits to control

their operation. They are:

•Flag bit to indicate that an interrupt event

occurred

•Enable bit that allows program execution to

branch to the interrupt vector address when the

flag bit is set

•Priority bit to select high priority or low priority

The interrupt priority feature is enabled by setting the

IPEN bit (RCON<7>). When interrupt priority is

enabled, there are two bits which enable interrupts

globally. Setting the GIEH bit (INTCON<7>) enables all

interrupts that have the priority bit set (high priority).

Setting the GIEL bit (INTCON<6>) enables all

interrupts that have the priority bit cleared (low priority).

When the interrupt flag, enable bit and appropriate

global interrupt enable bit are set, the interrupt will

vector immediately to address 0008h or 0018h,

depending on the priority bit setting. Individual

interrupts can be disabled through their corresponding

enable bits.

When the IPEN bit is cleared (default state), the

interrupt priority feature is disabled and interrupts are

compatible with PIC® mid-range devices. In

Compatibility mode, the interrupt priority bits for each

source have no effect. INTCON<6> is the PEIE bit

which enables/disables all peripheral interrupt sources.

INTCON<7> is the GIE bit which enables/disables all

interrupt sources. All interrupts branch to address

0008h in Compatibility mode.

When an interrupt is responded to, the global interrupt

enable bit is cleared to disable further interrupts. If the

IPEN bit is cleared, this is the GIE bit. If interrupt priority

levels are used, this will be either the GIEH or GIEL bit.

High-priority interrupt sources can interrupt a

low-priority interrupt. Low-priority interrupts are not

processed while high-priority interrupts are in progress.

The return address is pushed onto the stack and the

PC is loaded with the interrupt vector address (0008h

or 0018h). Once in the Interrupt Service Routine, the

source(s) of the interrupt can be determined by polling

the interrupt flag bits. The interrupt flag bits must be

cleared in software before re-enabling interrupts to

avoid recursive interrupts.

The “return from interrupt” instruction, RETFIE, exits

the interrupt routine and sets the GIE bit (GIEH or GIEL

if priority levels are used) which re-enables interrupts.

For external interrupt events, such as the INTx pins or

the PORTB input change interrupt, the interrupt latency

will be three to four instruction cycles. The exact

latency is the same for one or two-cycle instructions.

Individual interrupt flag bits are set regardless of the

status of their corresponding enable bit or the GIE bit.

Note: Do not use the MOVFF instruction to modify

any of the interrupt control registers while

any interrupt is enabled. Doing so may

cause erratic microcontroller behavior.

PIC18F87J50 FAMILY

FIGURE 9-1: PIC18F87J50 FAMILY INTERRUPT LOGIC

TMR0IE

GIE/GIEH

PEIE/GIEL

Wake-up if in

Interrupt to CPU

Vector to Location

0008h

INT2IF

INT2IE

INT2IP

INT1IF

INT1IE

INT1IP

TMR0IF

TMR0IE

TMR0IP

RBIF

RBIE

RBIP

IPEN

TMR0IF

TMR0IP

INT1IF

INT1IE

INT1IP

INT2IF

INT2IE

INT2IP

RBIF

RBIE

RBIP

INT0IF

INT0IE

PEIE/GIEL

Interrupt to CPU

Vector to Location

IPEN

0018h

PIR1<7:0>

PIE1<7:0>

IPR1<7:0>

High-Priority Interrupt Generation

Low-Priority Interrupt Generation

Idle or Sleep modes

GIE/GIEH

INT3IF

INT3IE

INT3IP

INT3IF

INT3IE

INT3IP

PIR2<7:0>

PIE2<7:0>

IPR2<7:0>

PIR3<7:0>

PIE3<7:0>

IPR3<7:0>

PIR1<7:0>

PIE1<7:0>

IPR1<7:0>

PIR2<7:0>

PIE2<7:0>

IPR2<7:0>

PIR3<7:0>

PIE3<7:0>

IPR3<7:0>

IPEN

PIC18F87J50 FAMILY

9.1 INTCON Registers

The INTCON registers are readable and writable

registers which contain various enable, priority and flag

bits.

Note: Interrupt flag bits are set when an interrupt

condition occurs regardless of the state of

its corresponding enable bit or the global

interrupt enable bit. User software should

ensure the appropriate interrupt flag bits

are clear prior to enabling an interrupt.

This feature allows for software polling.

R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-x

GIE/GIEH PEIE/GIEL TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF(1)

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 GIE/GIEH: Global Interrupt Enable bit

When IPEN = 0:

1 = Enables all unmasked interrupts

0 = Disables all interrupts

When IPEN = 1:

1 = Enables all high-priority interrupts

0 = Disables all interrupts

bit 6 PEIE/GIEL: Peripheral Interrupt Enable bit

When IPEN = 0:

1 = Enables all unmasked peripheral interrupts

0 = Disables all peripheral interrupts

When IPEN = 1:

1 = Enables all low-priority peripheral interrupts

0 = Disables all low-priority peripheral interrupts

bit 5 TMR0IE: TMR0 Overflow Interrupt Enable bit

1 = Enables the TMR0 overflow interrupt

0 = Disables the TMR0 overflow interrupt

bit 4 INT0IE: INT0 External Interrupt Enable bit

1 = Enables the INT0 external interrupt

0 = Disables the INT0 external interrupt

bit 3 RBIE: RB Port Change Interrupt Enable bit

1 = Enables the RB port change interrupt

0 = Disables the RB port change interrupt

bit 2 TMR0IF: TMR0 Overflow Interrupt Flag bit

1 = TMR0 register has overflowed (must be cleared in software)

0 = TMR0 register did not overflow

bit 1 INT0IF: INT0 External Interrupt Flag bit

1 = The INT0 external interrupt occurred (must be cleared in software)

0 = The INT0 external interrupt did not occur

bit 0 RBIF: RB Port Change Interrupt Flag bit(1)

1 = At least one of the RB7:RB4 pins changed state (must be cleared in software)

0 = None of the RB7:RB4 pins have changed state

Note 1: A mismatch condition will continue to set this bit. Reading PORTB will end the mismatch condition and

allow the bit to be cleared.

PIC18F87J50 FAMILY

R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1

RBPU INTEDG0 INTEDG1 INTEDG2 INTEDG3 TMR0IP INT3IP RBIP

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 RBPU: PORTB Pull-up Enable bit

1 = All PORTB pull-ups are disabled

0 = PORTB pull-ups are enabled by individual port latch values

bit 6 INTEDG0: External Interrupt 0 Edge Select bit

1 = Interrupt on rising edge

0 = Interrupt on falling edge

bit 5 INTEDG1: External Interrupt 1 Edge Select bit

1 = Interrupt on rising edge

0 = Interrupt on falling edge

bit 4 INTEDG2: External Interrupt 2 Edge Select bit

1 = Interrupt on rising edge

0 = Interrupt on falling edge

bit 3 INTEDG3: External Interrupt 3 Edge Select bit

1 = Interrupt on rising edge

0 = Interrupt on falling edge

bit 2 TMR0IP: TMR0 Overflow Interrupt Priority bit

1 =High priority

0 = Low priority

bit 1 INT3IP: INT3 External Interrupt Priority bit

1 =High priority

0 = Low priority

bit 0 RBIP: RB Port Change Interrupt Priority bit

1 =High priority

0 = Low priority

Note: Interrupt flag bits are set when an interrupt condition occurs regardless of the state of its corresponding

enable bit or the global interrupt enable bit. User software should ensure the appropriate interrupt flag bits

are clear prior to enabling an interrupt. This feature allows for software polling.

PIC18F87J50 FAMILY

R/W-1 R/W-1 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

INT2IP INT1IP INT3IE INT2IE INT1IE INT3IF INT2IF INT1IF

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 INT2IP: INT2 External Interrupt Priority bit

1 =High priority

0 = Low priority

bit 6 INT1IP: INT1 External Interrupt Priority bit

1 =High priority

0 = Low priority

bit 5 INT3IE: INT3 External Interrupt Enable bit

1 = Enables the INT3 external interrupt

0 = Disables the INT3 external interrupt

bit 4 INT2IE: INT2 External Interrupt Enable bit

1 = Enables the INT2 external interrupt

0 = Disables the INT2 external interrupt

bit 3 INT1IE: INT1 External Interrupt Enable bit

1 = Enables the INT1 external interrupt

0 = Disables the INT1 external interrupt

bit 2 INT3IF: INT3 External Interrupt Flag bit

1 = The INT3 external interrupt occurred (must be cleared in software)

0 = The INT3 external interrupt did not occur

bit 1 INT2IF: INT2 External Interrupt Flag bit

1 = The INT2 external interrupt occurred (must be cleared in software)

0 = The INT2 external interrupt did not occur

bit 0 INT1IF: INT1 External Interrupt Flag bit

1 = The INT1 external interrupt occurred (must be cleared in software)

0 = The INT1 external interrupt did not occur

Note: Interrupt flag bits are set when an interrupt condition occurs regardless of the state of its corresponding

enable bit or the global interrupt enable bit. User software should ensure the appropriate interrupt flag bits

are clear prior to enabling an interrupt. This feature allows for software polling.

PIC18F87J50 FAMILY

9.2 PIR Registers

The PIR registers contain the individual flag bits for the

peripheral interrupts. Due to the number of peripheral

interrupt sources, there are three Peripheral Interrupt

Request (Flag) registers (PIR1, PIR2, PIR3).

Note 1: Interrupt flag bits are set when an interrupt

condition occurs regardless of the state of

its corresponding enable bit or the Global

Interrupt Enable bit, GIE (INTCON<7>).

2: User software should ensure the

appropriate interrupt flag bits are cleared

prior to enabling an interrupt and after

servicing that interrupt.

R/W-0 R/W-0 R-0 R-0 R/W-0 R/W-0 R/W-0 R/W-0

PMPIF ADIF RC1IF TX1IF SSP1IF CCP1IF TMR2IF TMR1IF

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 PMPIF: Parallel Master Port Read/Write Interrupt Flag bit

1 = A read or a write operation has taken place (must be cleared in software)

0 =No read or write has occurred

bit 6 ADIF: A/D Converter Interrupt Flag bit

1 = An A/D conversion completed (must be cleared in software)

0 = The A/D conversion is not complete

bit 5 RC1IF: EUSART1 Receive Interrupt Flag bit

1 = The EUSART1 receive buffer, RCREG1, is full (cleared when RCREG1 is read)

0 = The EUSART1 receive buffer is empty

bit 4 TX1IF: EUSART1 Transmit Interrupt Flag bit

1 = The EUSART1 transmit buffer, TXREG1, is empty (cleared when TXREG1 is written)

0 = The EUSART1 transmit buffer is full

bit 3 SSP1IF: Master Synchronous Serial Port Interrupt Flag bit (MSSP1 module)

1 = The transmission/reception is complete (must be cleared in software)

0 = Waiting to transmit/receive

bit 2 CCP1IF: ECCP1 Interrupt Flag bit

Capture mode:

1 = A TMR1/TMR3 register capture occurred (must be cleared in software)

0 = No TMR1/TMR3 register capture occurred

Compare mode:

1 = A TMR1/TMR3 register compare match occurred (must be cleared in software)

0 = No TMR1/TMR3 register compare match occurred

PWM mode:

Unused in this mode.

bit 1 TMR2IF: TMR2 to PR2 Match Interrupt Flag bit

1 = TMR2 to PR2 match occurred (must be cleared in software)

0 = No TMR2 to PR2 match occurred

bit 0 TMR1IF: TMR1 Overflow Interrupt Flag bit

1 = TMR1 register overflowed (must be cleared in software)

0 = TMR1 register did not overflow

PIC18F87J50 FAMILY

R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

OSCFIF CM2IF CM1IF USBIF BCL1IF LVDIF TMR3IF CCP2IF

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 OSCFIF: Oscillator Fail Interrupt Flag bit

1 = Device oscillator failed, clock input has changed to INTOSC (must be cleared in software)

0 = Device clock operating

bit 6 CM2IF: Comparator 2 Interrupt Flag bit

1 = Comparator input has changed (must be cleared in software)

0 = Comparator input has not changed

bit 5 CM1IF: Comparator 1 Interrupt Flag bit

1 = Comparator input has changed (must be cleared in software)

0 = Comparator input has not changed

bit 4 USBIF: USB Interrupt Flag bit

1 = USB has requested an interrupt (must be cleared in software)

0 = No USB interrupt request

bit 3 BCL1IF: Bus Collision Interrupt Flag bit (MSSP1 module)

1 = A bus collision occurred (must be cleared in software)

0 = No bus collision occurred

bit 2 LVDIF: Low-Voltage Detect Interrupt Flag bit

1 = A low-voltage condition occurred (must be cleared in software)

0 =Device V

DDCORE voltage is above the regulator low-voltage trip point (above 2.45V)

bit 1 TMR3IF: TMR3 Overflow Interrupt Flag bit

1 = TMR3 register overflowed (must be cleared in software)

0 = TMR3 register did not overflow

bit 0 CCP2IF: ECCP2 Interrupt Flag bit

Capture mode:

1 = A TMR1/TMR3 register capture occurred (must be cleared in software)

0 = No TMR1/TMR3 register capture occurred

Compare mode:

1 = A TMR1/TMR3 register compare match occurred (must be cleared in software)

0 = No TMR1/TMR3 register compare match occurred

PWM mode:

Unused in this mode.

PIC18F87J50 FAMILY

R/W-0 R/W-0 R-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

SSP2IF BCL2IF RC2IF TX2IF TMR4IF CCP5IF CCP4IF CCP3IF

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 SSP2IF: Master Synchronous Serial Port 2 Interrupt Flag bit

1 = The transmission/reception is complete (must be cleared in software)

0 = Waiting to transmit/receive

bit 6 BCL2IF: Bus Collision Interrupt Flag bit (MSSP2 module)

1 = A bus collision occurred (must be cleared in software)

0 = No bus collision occurred

bit 5 RC2IF: EUSART2 Receive Interrupt Flag bit

1 = The EUSART2 receive buffer, RCREG2, is full (cleared when RCREG2 is read)

0 = The EUSART2 receive buffer is empty

bit 4 TX2IF: EUSART2 Transmit Interrupt Flag bit

1 = The EUSART2 transmit buffer, TXREG2, is empty (cleared when TXREG2 is written)

0 = The EUSART2 transmit buffer is full

bit 3 TMR4IF: TMR4 to PR4 Match Interrupt Flag bit

1 = TMR4 to PR4 match occurred (must be cleared in software)

0 = No TMR4 to PR4 match occurred

bit 2 CCP5IF: CCP5 Interrupt Flag bit

Capture mode:

1 = A TMR1/TMR3 register capture occurred (must be cleared in software)

0 = No TMR1/TMR3 register capture occurred

Compare mode:

1 = A TMR1/TMR3 register compare match occurred (must be cleared in software)

0 = No TMR1/TMR3 register compare match occurred

PWM mode:

Unused in this mode.

bit 1 CCP4IF: CCP4 Interrupt Flag bit

Capture mode:

1 = A TMR1/TMR3 register capture occurred (must be cleared in software)

0 = No TMR1/TMR3 register capture occurred

Compare mode:

1 = A TMR1/TMR3 register compare match occurred (must be cleared in software)

0 = No TMR1/TMR3 register compare match occurred

PWM mode:

Unused in this mode.

bit 0 CCP3IF: ECCP3 Interrupt Flag bit

Capture mode:

1 = A TMR1/TMR3 register capture occurred (must be cleared in software)

0 = No TMR1/TMR3 register capture occurred

Compare mode:

1 = A TMR1/TMR3 register compare match occurred (must be cleared in software)

0 = No TMR1/TMR3 register compare match occurred

PWM mode:

Unused in this mode.

PIC18F87J50 FAMILY

9.3 PIE Registers

The PIE registers contain the individual enable bits for

the peripheral interrupts. Due to the number of

peripheral interrupt sources, there are three Peripheral

Interrupt Enable registers (PIE1, PIE2, PIE3). When

IPEN = 0, the PEIE bit must be set to enable any of

these peripheral interrupts.

R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

PMPIE ADIE RC1IE TX1IE SSP1IE CCP1IE TMR2IE TMR1IE

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 PMPIE: Parallel Master Port Read/Write Interrupt Enable bit

1 = Enables the PM read/write interrupt

0 = Disables the PM read/write interrupt

bit 6 ADIE: A/D Converter Interrupt Enable bit

1 = Enables the A/D interrupt

0 = Disables the A/D interrupt

bit 5 RC1IE: EUSART1 Receive Interrupt Enable bit

1 = Enables the EUSART1 receive interrupt

0 = Disables the EUSART1 receive interrupt

bit 4 TX1IE: EUSART1 Transmit Interrupt Enable bit

1 = Enables the EUSART1 transmit interrupt

0 = Disables the EUSART1 transmit interrupt

bit 3 SSP1IE: Master Synchronous Serial Port Interrupt Enable bit (MSSP1 module)

1 = Enables the MSSP1 interrupt

0 = Disables the MSSP1 interrupt

bit 2 CCP1IE: ECCP1 Interrupt Enable bit

1 = Enables the ECCP1 interrupt

0 = Disables the ECCP1 interrupt

bit 1 TMR2IE: TMR2 to PR2 Match Interrupt Enable bit

1 = Enables the TMR2 to PR2 match interrupt

0 = Disables the TMR2 to PR2 match interrupt

bit 0 TMR1IE: TMR1 Overflow Interrupt Enable bit

1 = Enables the TMR1 overflow interrupt

0 = Disables the TMR1 overflow interrupt

PIC18F87J50 FAMILY

R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

OSCFIE CM2IE CM1IE USBIE BCL1IE LVDIE TMR3IE CCP2IE

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 OSCFIE: Oscillator Fail Interrupt Enable bit

1 = Enabled

0 = Disabled

bit 6 CM2IE: Comparator 2 Interrupt Enable bit

1 = Enabled

0 = Disabled

bit 5 CM1IE: Comparator 1 Interrupt Enable bit

1 = Enabled

0 = Disabled

bit 4 USBIE: USB Interrupt Enable bit

1 = Enabled

0 = Disabled

bit 3 BCL1IE: Bus Collision Interrupt Enable bit (MSSP1 module)

1 = Enabled

0 = Disabled

bit 2 LVDIE: Low-Voltage Detect Interrupt Enable bit

1 = Enabled

0 = Disabled

bit 1 TMR3IE: TMR3 Overflow Interrupt Enable bit

1 = Enabled

0 = Disabled

bit 0 CCP2IE: ECCP2 Interrupt Enable bit

1 = Enabled

0 = Disabled

PIC18F87J50 FAMILY

R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

SSP2IE BCL2IE RC2IE TX2IE TMR4IE CCP5IE CCP4IE CCP3IE

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 SSP2IE: Master Synchronous Serial Port 2 Interrupt Enable bit

1 = Enabled

0 = Disabled

bit 6 BCL2IE: Bus Collision Interrupt Enable bit (MSSP2 module)

1 = Enabled

0 = Disabled

bit 5 RC2IE: EUSART2 Receive Interrupt Enable bit

1 = Enabled

0 = Disabled

bit 4 TX2IE: EUSART2 Transmit Interrupt Enable bit

1 = Enabled

0 = Disabled

bit 3 TMR4IE: TMR4 to PR4 Match Interrupt Enable bit

1 = Enabled

0 = Disabled

bit 2 CCP5IE: CCP5 Interrupt Enable bit

1 = Enabled

0 = Disabled

bit 1 CCP4IE: CCP4 Interrupt Enable bit

1 = Enabled

0 = Disabled

bit 0 CCP3IE: ECCP3 Interrupt Enable bit

1 = Enabled

0 = Disabled

PIC18F87J50 FAMILY

9.4 IPR Registers

The IPR registers contain the individual priority bits for

the peripheral interrupts. Due to the number of

peripheral interrupt sources, there are three Peripheral

Interrupt Priority registers (IPR1, IPR2, IPR3). Using

the priority bits requires that the Interrupt Priority

Enable (IPEN) bit be set.

R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1

PMPIP ADIP RC1IP TX1IP SSP1IP CCP1IP TMR2IP TMR1IP

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 PMPIP: Parallel Master Port Read/Write Interrupt Priority bit

1 =High priority

0 = Low priority

bit 6 ADIP: A/D Converter Interrupt Priority bit

1 =High priority

0 = Low priority

bit 5 RC1IP: EUSART1 Receive Interrupt Priority bit

1 =High priority

0 = Low priority

bit 4 TX1IP: EUSART1 Transmit Interrupt Priority bit

1 =High priority

0 = Low priority

bit 3 SSP1IP: Master Synchronous Serial Port Interrupt Priority bit (MSSP1 module)

1 =High priority

0 = Low priority

bit 2 CCP1IP: ECCP1 Interrupt Priority bit

1 =High priority

0 = Low priority

bit 1 TMR2IP: TMR2 to PR2 Match Interrupt Priority bit

1 =High priority

0 = Low priority

bit 0 TMR1IP: TMR1 Overflow Interrupt Priority bit

1 =High priority

0 = Low priority

PIC18F87J50 FAMILY

R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1

OSCFIP CM2IP CM1IP USBIP BCL1IP LVDIP TMR3IP CCP2IP

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 OSCFIP: Oscillator Fail Interrupt Priority bit

1 =High priority

0 = Low priority

bit 6 CM2IP: Comparator 2 Interrupt Priority bit

1 =High priority

0 = Low priority

bit 5 C12IP: Comparator 1 Interrupt Priority bit

1 =High priority

0 = Low priority

bit 4 USBIP: USB Interrupt Priority bit

1 =High priority

0 = Low priority

bit 3 BCL1IP: Bus Collision Interrupt Priority bit (MSSP1 module)

1 =High priority

0 = Low priority

bit 2 LVDIP: Low-Voltage Detect Interrupt Priority bit

1 =High priority

0 = Low priority

bit 1 TMR3IP: TMR3 Overflow Interrupt Priority bit

1 =High priority

0 = Low priority

bit 0 CCP2IP: ECCP2 Interrupt Priority bit

1 =High priority

0 = Low priority

PIC18F87J50 FAMILY

R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1

SSP2IP BCL2IP RC2IP TX2IP TMR4IP CCP5IP CCP4IP CCP3IP

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 SSP2IP: Master Synchronous Serial Port 2 Interrupt Priority bit

1 =High priority

0 = Low priority

bit 6 BCL2IP: Bus Collision Interrupt Priority bit (MSSP2 module)

1 =High priority

0 = Low priority

bit 5 RC2IP: EUSART2 Receive Interrupt Priority bit

1 =High priority

0 = Low priority

bit 4 TX2IP: EUSART2 Transmit Interrupt Priority bit

1 =High priority

0 = Low priority

bit 3 TMR4IE: TMR4 to PR4 Interrupt Priority bit

1 =High priority

0 = Low priority

bit 2 CCP5IP: CCP5 Interrupt Priority bit

1 =High priority

0 = Low priority

bit 1 CCP4IP: CCP4 Interrupt Priority bit

1 =High priority

0 = Low priority

bit 0 CCP3IP: ECCP3 Interrupt Priority bit

1 =High priority

0 = Low priority

PIC18F87J50 FAMILY

9.5 RCON Register

The RCON register contains bits used to determine the

cause of the last Reset or wake-up from Idle or Sleep

modes. RCON also contains the bit that enables

interrupt priorities (IPEN).

R/W-0 U-0 R/W-1 R/W-1 R-1 R-1 R/W-0 R/W-0

IPEN —CMRI TO PD POR BOR

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 IPEN: Interrupt Priority Enable bit

1 = Enable priority levels on interrupts

0 = Disable priority levels on interrupts (PIC16CXXX Compatibility mode)

bit 6 Unimplemented: Read as ‘0’

bit 5 CM: Configuration Mismatch Flag bit

For details of bit operation, see Register 4-1.

bit 4 RI: RESET Instruction Flag bit

For details of bit operation, see Register 4-1.

bit 3 TO: Watchdog Timer Time-out Flag bit

For details of bit operation, see Register 4-1.

bit 2 PD: Power-Down Detection Flag bit

For details of bit operation, see Register 4-1.

bit 1 POR: Power-on Reset Status bit

For details of bit operation, see Register 4-1.

bit 0 BOR: Brown-out Reset Status bit

For details of bit operation, see Register 4-1.

PIC18F87J50 FAMILY

9.6 INTx Pin Interrupts

External interrupts on the RB0/INT0, RB1/INT1,

RB2/INT2 and RB3/INT3 pins are edge-triggered. If the

corresponding INTEDGx bit in the INTCON2 register is

set (= 1), the interrupt is triggered by a rising edge; if

the bit is clear, the trigger is on the falling edge. When

a valid edge appears on the RBx/INTx pin, the

corresponding flag bit, INTxIF, is set. This interrupt can

be disabled by clearing the corresponding enable bit,

INTxIE. Flag bit, INTxIF, must be cleared in software in

the Interrupt Service Routine before re-enabling the

interrupt.

All external interrupts (INT0, INT1, INT2 and INT3) can

wake-up the processor from the power-managed

modes if bit INTxIE was set prior to going into the

power-managed modes. If the Global Interrupt Enable

bit, GIE, is set, the processor will branch to the interrupt

vector following wake-up.

Interrupt priority for INT1, INT2 and INT3 is determined

by the value contained in the interrupt priority bits,

INT1IP (INTCON3<6>), INT2IP (INTCON3<7>) and

INT3IP (INTCON2<1>). There is no priority bit

associated with INT0. It is always a high-priority

interrupt source.

9.7 TMR0 Interrupt

In 8-bit mode (which is the default), an overflow in the

TMR0 register (FFh →00h) will set flag bit, TMR0IF. In

16-bit mode, an overflow in the TMR0H:TMR0L register

pair (FFFFh →0000h) will set TMR0IF. The interrupt

can be enabled/disabled by setting/clearing enable bit,

TMR0IE (INTCON<5>). Interrupt priority for Timer0 is

determined by the value contained in the interrupt prior-

ity bit, TMR0IP (INTCON2<2>). See Section 12.0

“Timer0 Module” for further details on the Timer0

module.

9.8 PORTB Interrupt-on-Change

An input change on PORTB<7:4> sets flag bit, RBIF

(INTCON<0>). The interrupt can be enabled/disabled

by setting/clearing enable bit, RBIE (INTCON<3>).

Interrupt priority for PORTB interrupt-on-change is

determined by the value contained in the interrupt

priority bit, RBIP (INTCON2<0>).

9.9 Context Saving During Interrupts

During interrupts, the return PC address is saved on

the stack. Additionally, the WREG, STATUS and BSR

registers are saved on the Fast Return Stack. If a fast

return from interrupt is not used (see Section 5.3

“Data Memory Organization”), the user may need to

save the WREG, STATUS and BSR registers on entry

to the Interrupt Service Routine. Depending on the

user’s application, other registers may also need to be

saved. Example 9-1 saves and restores the WREG,

STATUS and BSR registers during an Interrupt Service

Routine.

EXAMPLE 9-1: SAVING STATUS, WREG AND BSR REGISTERS IN RAM

MOVWF W_TEMP ; W_TEMP is in virtual bank

MOVFF STATUS, STATUS_TEMP ; STATUS_TEMP located anywhere

MOVFF BSR, BSR_TEMP ; BSR_TMEP located anywhere

;

; USER ISR CODE

;

MOVFF BSR_TEMP, BSR ; Restore BSR

MOVF W_TEMP, W ; Restore WREG

MOVFF STATUS_TEMP, STATUS ; Restore STATUS

PIC18F87J50 FAMILY

10.0 I/O PORTS

Depending on the device selected and features

enabled, there are up to nine ports available. Some

pins of the I/O ports are multiplexed with an alternate

function from the peripheral features on the device. In

general, when a peripheral is enabled, that pin may not

be used as a general purpose I/O pin.

Each port has three memory-mapped registers for its

operation:

• TRIS register (Data Direction register)

• PORT register (reads the levels on the pins of the

device)

• LAT register (Output Latch register)

Reading the PORT register reads the current status of

the pins, whereas writing to the PORT register writes to

the output latch (LAT) register.

Setting a TRIS bit (= 1) makes the corresponding

PORT pin an input (i.e., put the corresponding output

driver in a high-impedance mode). Clearing a TRIS bit

(= 0) makes the corresponding PORT pin an output

(i.e., put the contents of the corresponding LAT bit on

the selected pin).

The Data Latch (LAT register) is useful for

read-modify-write operations on the value that the I/O

pins are driving. Read-modify-write operations on the

LAT register read and write the latched output value for

PORT register.

A simplified model of a generic I/O port, without the

interfaces to other peripherals, is shown in Figure 10-1.

FIGURE 10-1: GENERIC I/O PORT

OPERATION

10.1 I/O Port Pin Capabilities

When developing an application, the capabilities of the

port pins must be considered. Outputs on some pins

have higher output drive strength than others. Similarly,

some pins can tolerate higher than VDD input levels.

10.1.1 INPUT PINS AND VOLTAGE

CONSIDERATIONS

The voltage tolerance of pins used as device inputs is

dependent on the pin’s input function. Pins that are used

as digital only inputs are able to handle DC voltages up

to 5.5V, a level typical for digital logic circuits. In contrast,

pins that also have analog input functions of any kind

(such as A/D and comparator inputs) can only tolerate

voltages up to VDD. Voltage excursions beyond VDD on

these pins should be avoided.

Table 10-1 summarizes the input capabilities. Refer to

Section 28.0 “Electrical Characteristics” for more

details.

TABLE 10-1: INPUT VOLTAGE LEVELS

10.1.2 PIN OUTPUT DRIVE

When used as digital I/O, the output pin drive strengths

vary for groups of pins intended to meet the needs for

a variety of applications. In general, there are three

classes of output pins in terms of drive capability.

PORTB and PORTC, as well as PORTA<7:6>, are

designed to drive higher current loads, such as LEDs.

PORTD, PORTE and PORTJ are capable of driving

digital circuits associated with external memory

devices. They can also drive LEDs, but only those with

smaller current requirements. PORTF, PORTG and

PORTH, along with PORTA<5:0>, have the lowest

drive level, but are capable of driving normal digital

circuit loads with a high input impedance.

Data

Bus

WR LAT

WR TRIS

RD PORT

Data Latch

TRIS Latch

RD TRIS

Input

Buffer

I/O pin

RD LAT

or PORT

Port or Pin Tolerated

Input Description

PORTA<5:0> VDD Only VDD input levels

tolerated.

PORTC<1:0>

PORTF<6:1>

PORTH<7:4>(1)

PORTB<7:0> 5.5V Tolerates input levels

above VDD, useful for

most standard logic.

PORTC<7:2>

PORTD<7:0>

PORTE<7:0>

PORTF<7>

PORTG<4:0>

PORTH<3:0>(1)

PORTJ<7:0>(1)

Note 1: These ports are not available on 64-pin

devices.

PIC18F87J50 FAMILY

Table 10-2 summarizes the output capabilities of the

ports. Refer to the “Absolute Maximum Ratings” in

Section 28.0 “Electrical Characteristics” for more

details.

TABLE 10-2: OUTPUT DRIVE LEVELS

10.1.3 PULL-UP CONFIGURATION

Four of the I/O ports (PORTB, PORTD, PORTE and

PORTJ) implement configurable weak pull-ups on all

pins. These are internal pull-ups that allow floating

digital input signals to be pulled to a consistent level,

without the use of external resistors.

The pull-ups are enabled with a single bit for each of the

ports: RBPU (INTCON2<7>) for PORTB, and RDPU,

REPU and RJPU (PORTG<7:5>) for the other ports.

10.1.4 OPEN-DRAIN OUTPUTS

The output pins for several peripherals are also

equipped with a configurable open-drain output option.

This allows the peripherals to communicate with

external digital logic operating at a higher voltage level,

without the use of level translators.

The open-drain option is implemented on port pins

specifically associated with the data and clock outputs

of the EUSARTs, the MSSP modules (in SPI mode) and

the CCP and ECCP modules. It is selectively enabled

by setting the open-drain control bit for the correspond-

ing module in the ODCON registers (Register 10-1,

is discussed in more detail with the individual port

where these peripherals are multiplexed.

The ODCON registers all reside in the SFR configuration

space, and share the same SFR addresses as the Timer1

registers (see

Section 5.3.5.1 “Shared Address SFRs”

for more details). The ODCON registers are accessed by

setting the ADSHR bit (WDTCON<4>).

When the open-drain option is required, the output pin

must also be tied through an external pull-up resistor

provided by the user to a higher voltage level, up to

5.5V (Figure 10-2). When a digital logic high signal is

output, it is pulled up to the higher voltage level.

FIGURE 10-2: USING THE OPEN-DRAIN

OUTPUT (USART SHOWN

AS EXAMPLE)

10.1.5 TTL INPUT BUFFER OPTION

Many of the digital I/O ports use Schmitt Trigger (ST)

input buffers. While this form of buffering works well

with many types of input, some applications may

require TTL level signals to interface with external logic

devices. This is particularly true with the EMB and the

Parallel Master Port (PMP), which are particularly likely

to be interfaced to TTL level logic or memory devices.

The inputs for the PMP can be optionally configured for

TTL buffers with the PMPTTL bit in the PADCFG1 reg-

ister (Register 10-4). Setting this bit configures all data

and control input pins for the PMP to use TTL buffers.

By default, these PMP inputs use the port’s ST buffers.

As with the ODCON registers, the PADCFG1 register

resides in the SFR configuration space; it shares the

same memory address as the TMR2 register.

PADCFG1 is accessed by setting the ADSHR bit

(WDTCON<4>).

Port Drive Description

PORTA Minimum Intended for indication.

PORTF

PORTG

PORTH(1)

PORTD Medium Sufficient drive levels for

external memory interfacing

as well as indication.

PORTE

PORTJ(1)

PORTB High Suitable for direct LED drive

levels.

PORTC

Note 1: These ports are not available on 64-pin

devices.

Note: RJPU is implemented on 80-pin devices

only.

TXX

PIC18F87J50

+5V

(at logic ‘1’)

3.3V

VDD 5V

PIC18F87J50 FAMILY

U-0 U-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

— — — CCP5OD CCP4OD ECCP3OD ECCP2OD ECCP1OD

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7-5 Unimplemented: Read as ‘0’

bit 4-3 CCP5OD:CCP4OD: CCPx Open-Drain Output Enable bits

1 = Open-drain output on CCPx pin (Capture/PWM modes) enabled

0 = Open-drain output disabled

bit 2-0 ECCP3OD:ECCP1OD: ECCPx Open-Drain Output Enable bits

1 = Open-drain output on ECCPx pin (Capture mode) enabled

0 = Open-drain output disabled

U-0 U-0 U-0 U-0 U-0 U-0 R/W-0 R/W-0

— — — — — — U2OD U1OD

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7-2 Unimplemented: Read as ‘0’

bit 1-0 U2OD:U1OD: EUSARTx Open-Drain Output Enable bits

1 = Open-drain output on TXx/CKx pin enabled

0 = Open-drain output disabled

U-0 U-0 U-0 U-0 U-0 U-0 R/W-0 R/W-0

— — — — — — SPI2OD SPI1OD

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7-2 Unimplemented: Read as ‘0’

bit 1-0 SPI2OD:SPI1OD: SPI Open-Drain Output Enable bits

1 = Open-drain output on SDOx pin enabled

0 = Open-drain output disabled

PIC18F87J50 FAMILY

10.2 PORTA, TRISA and

LATA Registers

PORTA is a 6-bit wide, bidirectional port. The

corresponding Data Direction register is TRISA. The

corresponding Output Latch register is LATA.

The RA4 pin is multiplexed with the Timer0 module clock

input to become the RA4/T0CKI pin. It is also multi-

plexed as the Parallel Master Port Data pin. The other

PORTA pins are multiplexed with the analog VREF+ and

VREF- inputs. The operation of pins RA5:RA0 as A/D

Converter inputs is selected by clearing or setting the

control bits in the ANCON0 register.

The RA4/T0CKI pin is a Schmitt Trigger input. All other

PORTA pins have TTL input levels and full CMOS

output drivers.

The TRISA register controls the direction of the PORTA

pins, even when they are being used as analog inputs.

The user must ensure the bits in the TRISA register are

maintained set when using them as analog inputs.

OSC2/CLKO/RA6 and OSC1/CLKI/RA7 normally

serve as the external circuit connections for the

external (primary) oscillator circuit (HS and HSPLL

Oscillator modes), or the external clock input (EC and

ECPLL Oscillator modes). In these cases, RA6 and

RA7 are not available as digital I/O and their

corresponding TRIS and LAT bits are read as ‘0’.

For INTOSCx and INTOSCPLLx Oscillator modes

(FOSC2 Configuration bit is ‘0’), either RA7, or both

RA6 and RA7, automatically become available as digi-

tal I/O, depending on the oscillator mode selected.

When RA6 is not configured as a digital I/O, in these

cases, it provides a clock output at FOSC/4. A list of the

possible configurations for RA6 and RA7, based on

oscillator mode, is provided in Register 10-3. For these

pins, the corresponding PORTA, TRISA and LATA bits

are only defined when the pins are configured as I/O.

TABLE 10-3: FUNCTION OF RA7:RA6 IN

INTOSC AND INTOSCPLL

MODES

EXAMPLE 10-1: INITIALIZING PORTA

U-0 U-0 U-0 U-0 U-0 U-0 U-0 R/W-0

— — — — — — —PMPTTL

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7-1 Unimplemented: Read as ‘0’

bit 0 PMPTTL: PMP Module TTL Input Buffer Select bit

1 = PMP module uses TTL input buffers

0 = PMP module uses Schmitt Trigger input buffers

Note 1: The RA5 (RA5/PMD4/AN4/C2INA) pin is a

multiplexed A/D convertor, Parallel Master

Port data and also a Comparator 2 input A.

(PMP pin placement depends on the

PMPMX Configuration bit.)

2: RA5 and RA3:RA0 are configured as

analog inputs on any Reset and are read

as ‘0’. RA4 is configured as a digital input.

Oscillator Mode

(FOSC2:FOSC0 Configuration bits) RA6 RA7

INTOSCPLLO (011) CLKO I/O

INTOSCPLL (010) I/O I/O

INTOSCO (001) CLKO I/O

INTOSC (000) I/O I/O

Legend: CLKO = FOSC/4 clock output; I/O = digital

port.

CLRF PORTA ; Initialize PORTA by

; clearing output

; data latches

CLRF LATA ; Alternate method to

; clear data latches

BSF WDTCON,ADSHR ; Enable write/read to

; the shared SFR

MOVLW 1Fh ; Configure A/D

MOVWF ANCON0 ; for digital inputs

BCF WDTCON,ADSHR ; Disable write/read

; to the shared SFR

MOVLW 0CFh ; Value used to

; initialize

; data direction

MOVWF TRISA ; Set RA<3:0> as inputs,

; RA<5:4> as outputs

PIC18F87J50 FAMILY

TABLE 10-4: PORTA FUNCTIONS

Pin Name Function TRIS

Setting I/O I/O

Type Description

RA0/AN0 RA0 0O DIG LATA<0> data output; not affected by analog input.

1I TTL PORTA<0> data input; disabled when analog input enabled.

AN0 1I ANA A/D input channel 0. Default input configuration on POR; does not

affect digital output.

RA1/AN1 RA1 0O DIG LATA<1> data output; not affected by analog input.

1I TTL PORTA<1> data input; disabled when analog input enabled.

AN1 1I ANA A/D input channel 1. Default input configuration on POR; does not

affect digital output.

RA2/AN2/VREF-RA2 0O DIG LATA<2> data output; not affected by analog input. Disabled when

CVREF output enabled.

1I TTL PORTA<2> data input. Disabled when analog functions enabled;

disabled when CVREF output enabled.

AN2 1I ANA A/D input channel 2 . Default input configuration on POR; not affected

by analog output.

VREF-1I ANA A/D low reference voltage input.

RA3/AN3/VREF+RA3 0O DIG LATA<3> data output; not affected by analog input.

1I TTL PORTA<3> data input; disabled when analog input enabled.

AN3 1I ANA A/D input channel 3. Default input configuration on POR.

VREF+1I ANA A/D high reference voltage input.

RA4/T0CKI/

PMD5

RA4 0O DIG LATA<4> data output.

1I ST PORTA<4> data input; default configuration on POR.

T0CKI xI ST Timer0 clock input.

PMD5(1,2) xO DIG Parallel Master Port data output.

xI TTL Parallel Master Port data output.

RA5/PMD4/

AN4/C2INA

RA5 0O DIG LATA<5> data output; not affected by analog input.

1I TTL PORTA<5> data input; disabled when analog input enabled.

PMD4(1,2) xO DIG Parallel Master Port data output.

xI TTL Parallel Master Port data output.

AN4 1I ANA A/D input channel 4. Default configuration on POR.

C2INA 1I ANA Comparator2 input A.

Legend: O = Output, I = Input, ANA = Analog Signal, DIG = Digital Output, ST = Schmitt Buffer Input, TTL = TTL Buffer Input,

x = Don’t care (TRIS bit does not affect port direction or is overridden for this option).

Note 1: When PMPMX = 0.

2: Available on 80-pin devices only.

PIC18F87J50 FAMILY

TABLE 10-5: SUMMARY OF REGISTERS ASSOCIATED WITH PORTA

Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Reset

Values

on Page:

PORTA —— RA5 RA4 RA3 RA2 RA1 RA0 65

LATA —— LATA5 LATA4 LATA3 LATA2 LATA1 LATA0 64

TRISA —— TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 64

ANCON0(1) PCFG7 —— PCFG4 PCFG3 PCFG2 PCFG1 PCFG0 63

Legend: — = unimplemented, read as ‘0’. Shaded cells are not used by PORTA.

Note 1: Configuration SFR, overlaps with default SFR at this address; available only when WDTCON<4> = 1.

PIC18F87J50 FAMILY

10.3 PORTB, TRISB and

LATB Registers

PORTB is an 8-bit wide, bidirectional port. The corre-

sponding Data Direction register is TRISB. All pins on

PORTB are digital only and tolerate voltages up to

5.5V.

Each of the PORTB pins has a weak internal pull-up. A

single control bit can turn on all the pull-ups. This is

performed by clearing bit, RBPU (INTCON2<7>). The

weak pull-up is automatically turned off when the port

pin is configured as an output. The pull-ups are

disabled on a Power-on Reset.

Four of the PORTB pins (RB7:RB4) have an

interrupt-on-change feature. Only pins configured as

inputs can cause this interrupt to occur (i.e., any

RB7:RB4 pin configured as an output is excluded from

the interrupt-on-change comparison). The input pins

(of RB7:RB4) are compared with the old value latched

on the last read of PORTB. The “mismatch” outputs of

RB7:RB4 are ORed together to generate the RB Port

Change Interrupt with Flag bit, RBIF (INTCON<0>).

This interrupt can wake the device from

power-managed modes. The user, in the Interrupt

Service Routine, can clear the interrupt in the following

manner:

a) Any read or write of PORTB (except with the

MOVFF (ANY), PORTB instruction). This will

end the mismatch condition.

b) Clear flag bit, RBIF.

A mismatch condition will continue to set flag bit, RBIF.

Reading PORTB will end the mismatch condition and

allow flag bit, RBIF, to be cleared.

The interrupt-on-change feature is recommended for

wake-up on key depression operation and operations

where PORTB is only used for the interrupt-on-change

feature. Polling of PORTB is not recommended while

using the interrupt-on-change feature.

For 80-pin devices, RB3 can be configured as the

alternate peripheral pin for the ECCP2 module and

Enhanced PWM output 2A by clearing the CCP2MX

Configuration bit. This applies only to 80-pin devices

operating in Extended Microcontroller mode. If the

device is in Microcontroller mode, the alternate

assignment for ECCP2 is RE7. As with other ECCP2

configurations, the user must ensure that the TRISB<3>

bit is set appropriately for the intended operation. Ports,

RB1, RB2, RB3, RB4 and RB5, are multiplexed with

the Parallel Master Port address.

EXAMPLE 10-2: INITIALIZING PORTB

CLRF PORTB ; Initialize PORTB by

; clearing output

; data latches

CLRF LATB ; Alternate method to clear

; output data latches

MOVLW 0CFh ; Value used to initialize

; data direction

MOVWF TRISB ; Set RB<3:0> as inputs

; RB<5:4> as outputs

; RB<7:6> as inputs

PIC18F87J50 FAMILY

TABLE 10-6: PORTB FUNCTIONS

Pin Name Function TRIS

Setting I/O I/O

Type Description

RB0/FLT0/INT0 RB0 0O DIG LATB<0> data output.

1I TTL PORTB<0> data input; weak pull-up when RBPU bit is cleared.

FLT0 1I ST Enhanced PWM Fault input (ECCP1 module); enabled in software.

INT0 1I ST External interrupt 0 input.

RB1/INT1/

PMA4

RB1 0O DIG LATB<1> data output.

1I TTL PORTB<1> data input; weak pull-up when RBPU bit is cleared.

INT1 1I ST External interrupt 1 input.

PMA4 xO — Parallel Master Port address out.

RB2/INT2/

PMA3

RB2 0O DIG LATB<2> data output.

1I TTL PORTB<2> data input; weak pull-up when RBPU bit is cleared.

INT2 1I ST External interrupt 2 input.

PMA3 xO — Parallel Master Port address out.

RB3/INT3/

ECCP2/P2A/

PMA2

RB3 0O DIG LATB<3> data output.

1I TTL PORTB<3> data input; weak pull-up when RBPU bit is cleared.

INT3 1I ST External interrupt 3 input.

ECCP2(1) 0O DIG ECCP2 compare output and ECCP2 PWM output; takes priority over port

data.

1I ST ECCP2 capture input.

P2A(1) 0O DIG ECCP2 Enhanced PWM output, channel A. May be configured for tri-state

during Enhanced PWM shutdown events. Takes priority over port data.

PMA2 xO — Parallel Master Port address out.

RB4/KBI0/

PMA1

RB4 0O DIG LATB<4> data output.

1I TTL PORTB<4> data input; weak pull-up when RBPU bit is cleared.

KBI0 I TTL Interrupt-on-pin change.

PMA1 xO — Parallel Master Port address out.

RB5/KBI1/

PMA0

RB5 0O DIG LATB<5> data output.

1I TTL PORTB<5> data input; weak pull-up when RBPU bit is cleared.

KBI1 I TTL Interrupt-on-pin change.

PMA0 xO — Parallel Master Port address out.

RB6/KBI2/PGC RB6 0O DIG LATB<6> data output.

1I TTL PORTB<6> data input; weak pull-up when RBPU bit is cleared.

KBI2 1I TTL Interrupt-on-pin change.

PGC xI ST Serial execution (ICSP™) clock input for ICSP and ICD operation.(2)

RB7/KBI3/PGD RB7 0O DIG LATB<7> data output.

1I TTL PORTB<7> data input; weak pull-up when RBPU bit is cleared.

KBI3 1I TTL Interrupt-on-pin change.

PGD xO DIG Serial execution data output for ICSP and ICD operation.(2)

xI ST Serial execution data input for ICSP and ICD operation.(2)

Legend: O = Output, I = Input, DIG = Digital Output, ST = Schmitt Buffer Input, TTL = TTL Buffer Input,

x = Don’t care (TRIS bit does not affect port direction or is overridden for this option).

Note 1: Alternate assignment for ECCP2/P2A when the CCP2MX Configuration bit is cleared (Extended Microcontroller mode,

80-pin devices only). Default assignment is RC1.

2: All other pin functions are disabled when ICSP™ or ICD are enabled.

PIC18F87J50 FAMILY

TABLE 10-7: SUMMARY OF REGISTERS ASSOCIATED WITH PORTB

Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Reset

Values

on Page:

PORTB RB7 RB6 RB5 RB4 RB3 RB2 RB1 RB0 65

LATB LATB7 LATB6 LATB5 LATB4 LATB3 LATB2 LATB1 LATB0 64

TRISB TRISB7 TRISB6 TRISB5 TRISB4 TRISB3 TRISB2 TRISB1 TRISB0 64

INTCON GIE/GIEH PEIE/GIEL TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 61

INTCON2 RBPU INTEDG0 INTEDG1 INTEDG2 INTEDG3 TMR0IP INT3IP RBIP 61

INTCON3 INT2IP INT1IP INT3IE INT2IE INT1IE INT3IF INT2IF INT1IF 61

Legend: Shaded cells are not used by PORTB.

PIC18F87J50 FAMILY

10.4 PORTC, TRISC and

LATC Registers

PORTC is an 8-bit wide, bidirectional port. Only

PORTC pins, RC2 through RC7, are digital only pins

and can tolerate input voltages up to 5.5V.

PORTC is multiplexed with CCP, MSSP and EUSART

peripheral functions (Table 10-8). The pins have

Schmitt Trigger input buffers. The pins for CCP, SPI

and EUSART are also configurable for open-drain out-

put whenever these functions are active. Open-drain

configuration is selected by setting the SPIxOD,

ECCPxOD and UxOD control bits in the ODCON regis-

ters (see Section 10.1.3 “Pull-up Configuration” for

more information).

RC1 is normally configured as the default peripheral

pin for the ECCP2 module. Assignment of ECCP2 is

controlled by Configuration bit, CCP2MX (default state,

CCP2MX = 1).

When enabling peripheral functions, care should be

taken in defining TRIS bits for each PORTC pin. Some

peripherals override the TRIS bit to make a pin an output,

while other peripherals override the TRIS bit to make a

pin an input. The user should refer to the corresponding

peripheral section for the correct TRIS bit settings.

The contents of the TRISC register are affected by

peripheral overrides. Reading TRISC always returns

the current contents, even though a peripheral device

may be overriding one or more of the pins.

EXAMPLE 10-3: INITIALIZING PORTC

Note: These pins are configured as digital inputs

on any device Reset.

CLRF PORTC ; Initialize PORTC by

; clearing output

; data latches

CLRF LATC ; Alternate method to clear

; output data latches

MOVLW 0CFh ; Value used to initialize

; data direction

MOVWF TRISC ; Set RC<3:0> as inputs

; RC<5:4> as outputs

; RC<7:6> as inputs

PIC18F87J50 FAMILY

TABLE 10-8: PORTC FUNCTIONS

Pin Name Function TRIS

Setting I/O I/O

Type Description

RC0/T1OSO/

T13CKI

RC0 0O DIG LATC<0> data output.

1I ST PORTC<0> data input.

T1OSO xO ANA Timer1 oscillator output; enabled when Timer1 oscillator enabled. Disables

digital I/O.

T13CKI 1I ST Timer1/Timer3 counter input.

RC1/T1OSI/

ECCP2/P2A

RC1 0O DIG LATC<1> data output.

1I ST PORTC<1> data input.

T1OSI xI ANA Timer1 oscillator input; enabled when Timer1 oscillator enabled. Disables

digital I/O.

ECCP2(1) 0O DIG ECCP2 compare output and ECCP2 PWM output; takes priority over port

data.

1I ST ECCP2 capture input.

P2A(1) 0O DIG ECCP2 Enhanced PWM output, channel A. May be configured for tri-state

during Enhanced PWM shutdown events. Takes priority over port data.

RC2/ECCP1/

P1A

RC2 0O DIG LATC<2> data output.

1I ST PORTC<2> data input.

ECCP1 0O DIG ECCP1 compare output and ECCP1 PWM output; takes priority over port

data.

1I ST ECCP1 capture input.

P1A 0O DIG ECCP1 Enhanced PWM output, channel A. May be configured for tri-state

during Enhanced PWM shutdown events. Takes priority over port data.

RC3/SCK1/

SCL1

RC3 0O DIG LATC<3> data output.

1I ST PORTC<3> data input.

SCK1 0O DIG SPI clock output (MSSP1 module); takes priority over port data.

1I ST SPI clock input (MSSP1 module).

SCL1 0ODIGI

2C™ clock output (MSSP1 module); takes priority over port data.

1ISTI

2C clock input (MSSP1 module); input type depends on module setting.

RC4/SDI1/

SDA1

RC4 0O DIG LATC<4> data output.

1I ST PORTC<4> data input.

SDI1 1I ST SPI data input (MSSP1 module).

SDA1 1ODIGI

2C data output (MSSP1 module); takes priority over port data.

1ISTI

2C data input (MSSP1 module); input type depends on module setting.

RC5/SDO1/

C2OUT

RC5 0O DIG LATC<5> data output.

1I ST PORTC<5> data input.

SDO1 0O DIG SPI data output (MSSP1 module); takes priority over port data.

C2OUT xO DIG Comparator 2 output.

RC6/TX1/CK1 RC6 0O DIG LATC<6> data output.

1I ST PORTC<6> data input.

TX1 1O DIG Synchronous serial data output (EUSART1 module); takes priority over port data.

CK1 1O DIG Synchronous serial data input (EUSART1 module). User must configure as

an input.

1I ST Synchronous serial clock input (EUSART1 module).

Legend: O = Output, I = Input, ANA = Analog Signal, DIG = Digital Output, ST = Schmitt Buffer Input,

x = Don’t care (TRIS bit does not affect port direction or is overridden for this option).

Note 1: Default assignment for ECCP2/P2A when CCP2MX Configuration bit is set.

PIC18F87J50 FAMILY

TABLE 10-9: SUMMARY OF REGISTERS ASSOCIATED WITH PORTC

RC7/RX1/DT1 RC7 0O DIG LATC<7> data output.

1I ST PORTC<7> data input.

RX1 1I ST Asynchronous serial receive data input (EUSART1 module).

DT1 1O DIG Synchronous serial data output (EUSART1 module); takes priority over

port data.

1I ST Synchronous serial data input (EUSART1 module). User must configure as

an input.

TABLE 10-8: PORTC FUNCTIONS (CONTINUED)

Pin Name Function TRIS

Setting I/O I/O

Type Description

Legend: O = Output, I = Input, ANA = Analog Signal, DIG = Digital Output, ST = Schmitt Buffer Input,

x = Don’t care (TRIS bit does not affect port direction or is overridden for this option).

Note 1: Default assignment for ECCP2/P2A when CCP2MX Configuration bit is set.

Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Reset

Values

on Page:

PORTC RC7 RC6 RC5 RC4 RC3 RC2 RC1 RC0 65

LATC LATC7 LATBC6 LATC5 LATCB4 LATC3 LATC2 LATC1 LATC0 64

TRISC TRISC7 TRISC6 TRISC5 TRISC4 TRISC3 TRISC2 TRISC1 TRISC0 64

PIC18F87J50 FAMILY

10.5 PORTD, TRISD and

LATD Registers

PORTD is an 8-bit wide, bidirectional port. All pins on

PORTD are digital only and tolerate voltages up to

5.5V.

All pins on PORTD are implemented with Schmitt

Trigger input buffers. Each pin is individually

configurable as an input or output.

On 80-pin devices, PORTD is multiplexed with the

system bus as part of the external memory interface.

I/O port and other functions are only available when the

interface is disabled by setting the EBDIS bit

(MEMCON<7>). When the interface is enabled,

PORTD is the low-order byte of the multiplexed

address/data bus (AD7:AD0). The TRISD bits are also

overridden.

PORTD can also be configured to function as an 8-bit

wide Parallel Master Port data. In this mode, Parallel

Master Port takes priority over the other digital I/O (but

not the external memory interface). This multiplexing is

available when PMPMX = 1. When the Parallel Master

Port is active, the input buffers are TTL. For more

information, refer to Section 11.0 “Parallel Master

Port”

Each of the PORTD pins has a weak internal pull-up.

The pull-ups are provided to keep the inputs at a known

state for the external memory interface while powering

up. A single control bit can turn off all the pull-ups. This

is performed by clearing bit, RDPU (PORTG<7>). The

weak pull-up is automatically turned off when the port

pin is configured as an output. The pull-ups are

disabled on all device Resets.

EXAMPLE 10-4: INITIALIZING PORTD

Note: These pins are configured as digital inputs

on any device Reset.

CLRF PORTD ; Initialize PORTD by

; clearing output

; data latches

CLRF LATD ; Alternate method to clear

; output data latches

MOVLW 0CFh ; Value used to initialize

; data direction

MOVWF TRISD ; Set RD<3:0> as inputs

; RD<5:4> as outputs

; RD<7:6> as inputs

PIC18F87J50 FAMILY

TABLE 10-10: PORTD FUNCTIONS

Pin Name Function TRIS

Setting I/O I/O

Type Description

RD0/AD0/

PMD0

RD0 0O DIG LATD<0> data output.

1I ST PORTD<0> data input.

AD0(2) xO DIG External memory interface, address/data bit 0 output.(1)

xI TTL External memory interface, data bit 0 input.(1)

PMD0(3) xO DIG Parallel Master Port data out.

xI TTL Parallel Master Port data input.

RD1/AD1/

PMD1

RD1 0O DIG LATD<1> data output.

1I ST PORTD<1> data input.

AD1(2) xO DIG External memory interface, address/data bit 1 output.(1)

xI TTL External memory interface, data bit 1 input.(1)

PMD1(3) xO DIG Parallel Master Port data out.

xI TTL Parallel Master Port data input.

RD2/AD2/

PMD2

RD2 0O DIG LATD<2> data output.

1I ST PORTD<2> data input.

AD2(2) xO DIG External memory interface, address/data bit 2 output.(1)

xI TTL External memory interface, data bit 2 input.(1)

PMD2(3) xO DIG Parallel Master Port data out.

xI TTL Parallel Master Port data input.

RD3/AD3/

PMD3

RD3 0O DIG LATD<3> data output.

1I ST PORTD<3> data input.

AD3(2) xO DIG External memory interface, address/data bit 3 output.(1)

xI TTL External memory interface, data bit 3 input.(1)

PMD3(3) xO DIG Parallel Master Port data out.

xI TTL Parallel Master Port data input.

RD4/AD4/

PMD4/SDO2

RD4 0O DIG LATD<4> data output.

1I ST PORTD<4> data input.

AD4(2) xO DIG External memory interface, address/data bit 4 output.(1)

xI TTL External memory interface, data bit 4 input.(1)

PMD4(3) xO DIG Parallel Master Port data out.

xI TTL Parallel Master Port data input.

SDO2 0O DIG SPI data output (MSSP2 module); takes priority over port data.

RD5/AD5/

PMD5/SDI2/

SDA2

RD5 0O DIG LATD<5> data output.

1I ST PORTD<5> data input.

AD5(2) xO DIG External memory interface, address/data bit 5 output.(1)

xI TTL External memory interface, data bit 5 input.(1)

PMD5(3) xO DIG Parallel Master Port data out.

xI TTL Parallel Master Port data input.

SDI2 1I ST SPI data input (MSSP2 module).

SDA2 1ODIGI

2C™ data output (MSSP2 module); takes priority over port data.

1ISTI

2C data input (MSSP2 module); input type depends on module setting.

Legend: O = Output, I = Input, DIG = Digital Output, ST = Schmitt Buffer Input, TTL = TTL Buffer Input,

x = Don’t care (TRIS bit does not affect port direction or is overridden for this option).

Note 1: External memory interface I/O takes priority over all other digital and PMP I/O.

2: Available on 80-pin devices only.

3: When PMPMX = 1.

PIC18F87J50 FAMILY

TABLE 10-11: SUMMARY OF REGISTERS ASSOCIATED WITH PORTD

RD6/AD6/

PMD6/SCK2/

SCL2

RD6 0O DIG LATD<6> data output.

1I ST PORTD<6> data input.

AD6(2) xO DIG-3 External memory interface, address/data bit 6 output.(1)

xI TTL External memory interface, data bit 6 input.(1)

PMD6(3) xO DIG Parallel Master Port data out.

xI TTL Parallel Master Port data input.

SCK2 0O DIG SPI clock output (MSSP2 module); takes priority over port data.

1I ST SPI clock input (MSSP2 module).

SCL2 0ODIGI

2C™ clock output (MSSP2 module); takes priority over port data.

1ISTI

2C clock input (MSSP2 module); input type depends on module

setting.

RD7/AD7/

PMD7/SS2

RD7 0O DIG LATD<7> data output.

1I ST PORTD<7> data input.

AD7(2) xO DIG External memory interface, address/data bit 7 output.(1)

xI TTL External memory interface, data bit 7 input.(1)

PMD7(3) xO DIG Parallel Master Port data out.

xI TTL Parallel Master Port data input.

SS2 xI TTL Slave select input for MSSP (MSSP2 module).

TABLE 10-10: PORTD FUNCTIONS (CONTINUED)

Pin Name Function TRIS

Setting I/O I/O

Type Description

Legend: O = Output, I = Input, DIG = Digital Output, ST = Schmitt Buffer Input, TTL = TTL Buffer Input,

x = Don’t care (TRIS bit does not affect port direction or is overridden for this option).

Note 1: External memory interface I/O takes priority over all other digital and PMP I/O.

2: Available on 80-pin devices only.

3: When PMPMX = 1.

Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Reset

Values

on Page:

PORTD RD7 RD6 RD5 RD4 RD3 RD2 RD1 RD0 65

LATD LATD7 LATD6 LATD5 LATD4 LATD3 LATD2 LATD1 LATD0 64

TRISD TRISD7 TRISD6 TRISD5 TRISD4TRISD3TRISD2TRISD1TRISD0 64

PORTG RDPU REPU RJPU(1) RG4 RG3 RG2 RG1 RG0 65

Legend: Shaded cells are not used by PORTD.

Note 1: Unimplemented on 64-pin devices, read as ‘0’.

PIC18F87J50 FAMILY

10.6 PORTE, TRISE and

LATE Registers

PORTE is an 8-bit wide, bidirectional port. All pins on

PORTE are digital only and tolerate voltages up to

5.5V.

All pins on PORTE are implemented with Schmitt

Trigger input buffers. Each pin is individually

configurable as an input or output.

On 80-pin devices, PORTE is multiplexed with the

system bus as part of the external memory interface.

I/O port and other functions are only available when the

interface is disabled, by setting the EBDIS bit

(MEMCON<7>). When the interface is enabled,

PORTE is the high-order byte of the multiplexed

address/data bus (AD15:AD8). The TRISE bits are also

overridden.

Each of the PORTE pins has a weak internal pull-up. A

single control bit can turn off all the pull-ups. This is

performed by clearing bit REPU (PORTG<6>). The

weak pull-up is automatically turned off when the port

pin is configured as an output. The pull-ups are

disabled on any device Reset.

PORTE is also multiplexed with Enhanced PWM

outputs B and C for ECCP1 and ECCP3 and outputs B,

C and D for ECCP2. For all devices, their default

assignments are on PORTE<6:3>. On 80-pin devices,

the multiplexing for the outputs of ECCP1 and ECCP3

is controlled by the ECCPMX Configuration bit.

Clearing this bit reassigns the P1B/P1C and P3B/P3C

outputs to PORTH.

For devices operating in Microcontroller mode, pin RE7

can be configured as the alternate peripheral pin for the

ECCP2 module and Enhanced PWM output 2A. This is

done by clearing the CCP2MX Configuration bit.

PORTE is also multiplexed with the Parallel Master

Port address lines. When PMPMX = 0, RE1 and RE0

are multiplexed with the control signals, PMPWR and

PMPRD.

RE3 can also be configured as the Reference Clock

Output (REFO) from the system clock. for further

details on this, refer to Section 2.5 “Reference Clock

Output”.

EXAMPLE 10-5: INITIALIZING PORTE

Note: These pins are configured as digital inputs

on any device Reset.

CLRF PORTE ; Initialize PORTE by

; clearing output

; data latches

CLRF LATE ; Alternate method to clear

; output data latches

MOVLW 03h ; Value used to initialize

; data direction

MOVWF TRISE ; Set RE<1:0> as inputs

; RE<7:2> as outputs

PIC18F87J50 FAMILY

TABLE 10-12: PORTE FUNCTIONS

Pin Name Function TRIS

Setting I/O I/O

Type Description

RE0/AD8/

PMRD/P2D

RE0 0O DIG LATE<0> data output.

1I ST PORTE<0> data input.

AD8(3) xO DIG External memory interface, address/data bit 8 output.(2)

xI TTL External memory interface, data bit 8 input.(2)

PMRD(5) xO DIG Parallel Master Port read strobe pin.

xI TTL Parallel Master Port read pin.

P2D 0O DIG ECCP2 Enhanced PWM output, channel D; takes priority over port

and PMP data. May be configured for tri-state during Enhanced PWM

shutdown events.

RE1/AD9/

PMWR/P2C

RE1 0O DIG LATE<1> data output.

1I ST PORTE<1> data input.

AD9(3) xO DIG External memory interface, address/data bit 9 output.(2)

xI TTL External memory interface, data bit 9 input.(2)

PMWR(5) xO DIG Parallel Master Port write strobe pin.

xI TTL Parallel Master Port write pin.

P2C 0O DIG ECCP2 Enhanced PWM output, channel C; takes priority over port

and PMP data. May be configured for tri-state during Enhanced PWM

shutdown events.

RE2/AD10/

PMBE/P2B

RE2 0O DIG LATE<2> data output.

1I ST PORTE<2> data input.

AD10(3) xO DIG External memory interface, address/data bit 10 output.(2)

xI TTL External memory interface, data bit 10 input.(2)

PMBE(5) xO DIG Parallel Master Port byte enable.

P2B 0O DIG ECCP2 Enhanced PWM output, channel B; takes priority over port and

PMP data. May be configured for tri-state during Enhanced PWM

shutdown events.

RE3/AD11/

PMA13/P3C/

REFO

RE3 0O DIG LATE<3> data output.

1I ST PORTE<3> data input.

AD11(3) xO DIG External memory interface, address/data bit 11 output.(2)

xI TTL External memory interface, data bit 11 input.(2)

PMA13 xO DIG Parallel Master Port address.

P3C(1) 0O DIG ECCP3 Enhanced PWM output, channel C; takes priority over port

and PMP data. May be configured for tri-state during Enhanced PWM

shutdown events.

REFO xO DIG Reference output clock.

RE4/AD12/

PMA12/P3B

RE4 0O DIG LATE<4> data output.

1I ST PORTE<4> data input.

AD12(3) xO DIG External memory interface, address/data bit 12 output.(2)

xI TTL External memory interface, data bit 12 input.(2)

PMA12 xO DIG Parallel Master Port address.

P3B(1) 0O DIG ECCP3 Enhanced PWM output, channel B; takes priority over port and

PMP data. May be configured for tri-state during Enhanced PWM

shutdown events.

Legend: O = Output, I = Input, DIG = Digital Output, ST = Schmitt Buffer Input, TTL = TTL Buffer Input,

x = Don’t care (TRIS bit does not affect port direction or is overridden for this option).

Note 1: Default assignments for P1B/P1C and P3B/P3C when ECCPMX Configuration bit is set (80-pin devices only).

2: External memory interface I/O takes priority over all other digital and PMP I/O.

3: Available on 80-pin devices only.

4: Alternate assignment for ECCP2/P2A when ECCP2MX Configuration bit is cleared (all devices in Microcontroller

mode).

5: Default configuration for PMP (PMPMX Configuration bit = 1).

PIC18F87J50 FAMILY

TABLE 10-13: SUMMARY OF REGISTERS ASSOCIATED WITH PORTE

RE5/AD13/

PMA11/P1C

RE5 0O DIG LATE<5> data output.

1I ST PORTE<5> data input.

AD13(3) xO DIG External memory interface, address/data bit 13 output.(2)

xI TTL External memory interface, data bit 13 input.(2)

PMA11 xO DIG Parallel Master Port address.

P1C(1) 0O DIG ECCP1 Enhanced PWM output, channel C; takes priority over port

and PMP data. May be configured for tri-state during Enhanced PWM

shutdown events.

RE6/AD14/

PMA10/P1B

RE6 0O DIG LATE<6> data output.

1I ST PORTE<6> data input.

AD14(3) xO DIG External memory interface, address/data bit 14 output.(2)

xI TTL External memory interface, data bit 14 input.(2)

PMA10 xO DIG Parallel Master Port address.

P1B(1) 0O DIG ECCP1 Enhanced PWM output, channel B; takes priority over port and

PMP data. May be configured for tri-state during Enhanced PWM

shutdown events.

RE7/AD15/

PMA9/ECCP2/

P2A

RE7 0O DIG LATE<7> data output.

1I ST PORTE<7> data input.

AD15(3) xO DIG External memory interface, address/data bit 15 output.(2)

xI TTL External memory interface, data bit 15 input.(2)

PMA9 xO DIG Parallel Master Port address.

ECCP2(4) 0O DIG ECCP2 compare output and ECCP2 PWM output; takes priority over

port data.

1I ST ECCP2 capture input.

P2A(4) 0O DIG ECCP2 Enhanced PWM output, channel A; takes priority over port and

PMP data. May be configured for tri-state during Enhanced PWM

shutdown events.

TABLE 10-12: PORTE FUNCTIONS (CONTINUED)

Pin Name Function TRIS

Setting I/O I/O

Type Description

Legend: O = Output, I = Input, DIG = Digital Output, ST = Schmitt Buffer Input, TTL = TTL Buffer Input,

x = Don’t care (TRIS bit does not affect port direction or is overridden for this option).

Note 1: Default assignments for P1B/P1C and P3B/P3C when ECCPMX Configuration bit is set (80-pin devices only).

2: External memory interface I/O takes priority over all other digital and PMP I/O.

3: Available on 80-pin devices only.

4: Alternate assignment for ECCP2/P2A when ECCP2MX Configuration bit is cleared (all devices in Microcontroller

mode).

5: Default configuration for PMP (PMPMX Configuration bit = 1).

Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Reset

Values

on Page:

PORTE RE7 RE6 RE5 RE4 RE3 RE2 RE1 RE0 65

LATE LATE7 LATE6 LATE5 LATE4 LATE3 LATE2 LATE1 LATE0 64

TRISE TRISE7 TRISE6 TRISE5 TRISE4 TRISE3 TRISE2 TRISE1 TRISE0 64

PORTG RDPU REPU RJPU(1) RG4 RG3 RG2 RG1 RG0 65

Legend: Shaded cells are not used by PORTE.

Note 1: Unimplemented on 64-pin devices, read as ‘0’.

PIC18F87J50 FAMILY

10.7 PORTF, LATF and TRISF Registers

PORTF is a 6-bit wide, bidirectional port. RF2, RF5 and

RF6 are analog inputs. These ports are configured as

analog inputs on a device Reset.

All pins on PORTF are implemented with Schmitt Trig-

ger input buffers. Each pin is individually configurable

as an input or output.

Pins, RF3 and RF4, are multiplexed with the USB mod-

ule. Depending on the configuration of the module, they

can serve as the differential data lines for the on-chip

USB transceiver. Both RF3 and RF4 have Schmitt

Trigger input buffers. As digital ports, they can only

function as digital inputs; the on-chip USB transceiver

must be disabled (UTRDIS (UCFG<3>) bit = 1) to use

the pin as digital inputs. When configured for USB oper-

ation, the data direction is determined automatically by

the configuration and status of the USB module at any

given time.

When Configuration bit, PMPMX = 0, PORTF is multi-

plexed with Parallel Master data port. This multiplexing

is available only in 80 pin devices.

EXAMPLE 10-6: INITIALIZING PORTF

Note 1: On device Resets, pins RF2, RF5 and

RF6 are configured as analog inputs and

are read as ‘0’.

2: To configure PORTF as digital I/O, set the

corresponding bits in ANCON0 and

ANCON1.

CLRF PORTF ; Initialize PORTF by

; clearing output

; data latches

CLRF LATF ; Alternate method to

; clear output latches

BSF WDTCON,ADSHR ; Enable write/read to

; the shared SFR

MOVLW 80h ; make RF2 digital

MOVWF ANCON0 ;

MOVLW 0Ch ; make RF<6:5> digital

MOVWF ANCON1 ;

BCF WDTCON,ADSHR ; Disable write/read to

; the shared SFR

MOVLW C0h ;

MOVWF TRISF ; Set RF5:RF2 as outputs,

; RF<7:6> as inputs

PIC18F87J50 FAMILY

TABLE 10-14: PORTF FUNCTIONS

Pin Name Function TRIS

Setting I/O I/O

Type Description

RF2/PMA5/

AN7/C2INB

RF2 0O DIG LATF<2> data output; not affected by analog input.

1I ST PORTF<2> data input; disabled when analog input enabled.

PMA5 xO DIG Parallel Master Port address.

AN7 1I ANA A/D input channel 7. Default configuration on POR.

C2INB xI ANA Comparator 2 input B.

RF3/D- RF3 1I ST PORTF<3> data input; disabled when analog input enabled.

D- O XVCR USB bus differential minus line output (internal transceiver).

I XVCR USB bus differential minus line input (internal transceiver).

RF4/D+ RF4 1I ST PORTF<4> data input; disabled when analog input enabled.

D+ O XVCR USB bus differential plus line output (internal transceiver).

I XVCR USB bus differential plus line input (internal transceiver).

RF5/PMD2/

AN10/C1INB/

CVREF

RF5 0O DIG LATF<5> data output; not affected by analog input. Disabled when

CVREF output enabled.

1I ST PORTF<5> data input; disabled when analog input enabled. Disabled

when CVREF output enabled.

PMD2(1) xO DIG Parallel Master Port data out.

xI TTL Parallel Master Port data input.

AN10 1I ANA A/D input channel 10 and Comparator C1+ input. Default input

configuration on POR.

C1INB xI ANA Comparator 1 input B.

CVREF xO ANA Comparator voltage reference output. Enabling this feature disables

digital I/O.

RF6/PMD1/

AN11/C1INA

RF6 0O DIG LATF<6> data output; not affected by analog input.

1I ST PORTF<6> data input; disabled when analog input enabled.

PMD1(1) xO DIG Parallel Master Port data out.

xI TTL Parallel Master Port data input.

AN11 1I ANA A/D input channel 11 and Comparator C1- input. Default input

configuration on POR; does not affect digital output.

C1INA xI ANA Comparator 1 input A.

RF7/PMD0/

SS1/C1OUT

RF7 0O DIG LATF<7> data output.

1I ST PORTF<7> data input.

PMD0(1) xO DIG Parallel Master Port data out.

xI TTL Parallel Master Port data input.

SS1 1I TTL Slave select input for MSSP1.

C1OUT xO DIG Comparator 1 output.

Legend: O = Output, I = Input, ANA = Analog Signal, DIG = Digital Output, ST = Schmitt Buffer Input, TTL = TTL Buffer Input,

XVCR = USB Transceiver, x = Don’t care (TRIS bit does not affect port direction or is overridden for this option).

Note 1: Alternate PMP configuration when the PMPMX Configuration bit = 0; available on 80-pin devices only.

PIC18F87J50 FAMILY

TABLE 10-15: SUMMARY OF REGISTERS ASSOCIATED WITH PORTF

Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Reset

Values

on Page:

PORTF RF7 RF6 RF5 RF4 RF3 RF2 ——65

LATF LATF7 LATF6 LATF5 LATF4 LATF3 LATF2 ——64

TRISF TRISF7 TRISF6 TRISF5 TRISF4 TRISF3 TRISF2 ——64

ANCON0(1) PCFG7 — — PCFG4 PCFG3 PCFG2 PCFG1 PCFG0 63

ANCON1(1) PCFG15 PCFG14 PCFG13 PCFG12 PCFG11 PCFG10 ——63

Legend: — = unimplemented, read as ‘0’. Shaded cells are not used by PORTF.

Note 1: Configuration SFR, overlaps with default SFR at this address; available only when WDTCON<4> = 1.

PIC18F87J50 FAMILY

10.8 PORTG, TRISG and

LATG Registers

PORTG is a 5-bit wide, bidirectional port. The corre-

sponding Data Direction register is TRISG. All pins on

PORTG are digital only and tolerate voltages up to

5.5V.

PORTG is multiplexed with EUSART2 functions

(Table 10-16). PORTG pins have Schmitt Trigger input

buffers. PORTG has pins multiplexed with the Parallel

Master Port.

When enabling peripheral functions, care should be

taken in defining TRIS bits for each PORTG pin. Some

peripherals override the TRIS bit to make a pin an

output, while other peripherals override the TRIS bit to

make a pin an input. The user should refer to the

corresponding peripheral section for the correct TRIS

bit settings. The pin override value is not loaded into

the TRIS register. This allows read-modify-write of the

TRIS register without concern due to peripheral

overrides.

Although the port itself is only five bits wide,

PORTG<7:5> bits are still implemented. These are

used to control the weak pull-ups on the I/O ports

associated with the External Memory Bus (PORTD,

PORTE and PORTJ). Setting these bits enables the

pull-ups. Since these are control bits and are not

associated with port I/O, the corresponding TRISG and

LATG bits are not implemented.

EXAMPLE 10-7: INITIALIZING PORTG

CLRF PORTG ; Initialize PORTG by

; clearing output

; data latches

CLRF LATG ; Alternate method to clear

; output data latches

MOVLW 04h ; Value used to initialize

; data direction

MOVWF TRISG ; Set RG1:RG0 as outputs

; RG2 as input

; RG4:RG3 as outputs

PIC18F87J50 FAMILY

TABLE 10-16: PORTG FUNCTIONS

Pin Name Function TRIS

Setting I/O I/O

Type Description

RG0/PMA8/

ECCP3/P3A

RG0 0O DIG LATG<0> data output.

1I ST PORTG<0> data input.

PMA8 xO DIG Parallel Master Port address.

ECCP3 O DIG ECCP3 compare and PWM output; takes priority over port data.

I ST ECCP3 capture input.

P3A 0O DIG ECCP3 Enhanced PWM output, channel A; takes priority over port and

PMP data. May be configured for tri-state during Enhanced PWM

shutdown events.

RG1/PMA7/

TX2/CK2/

RG1 0O DIG LATG<1> data output.

1I ST PORTG<1> data input.

PMA7 xO DIG Parallel Master Port address.

TX2 1O DIG Synchronous serial data output (EUSART2 module); takes priority over

port data.

CK2 1O DIG Synchronous serial data input (EUSART2 module). User must configure

as an input.

1I ST Synchronous serial clock input (EUSART2 module).

RG2/PMA6/

RX2/DT2

RG2 0O DIG LATG<2> data output.

1I ST PORTG<2> data input.

PMA6 xO DIG Parallel Master Port address.

RX2 1I ST Asynchronous serial receive data input (EUSART2 module).

DT2 1O DIG Synchronous serial data output (EUSART2 module); takes priority over

port data.

1I ST Synchronous serial data input (EUSART2 module). User must configure

as an input.

RG3/PMCS1/

CCP4/P3D

RG3 0O DIG LATG<3> data output.

1I ST PORTG<3> data input.

PMCS1 xO DIG Parallel Master Port address chip select 1

xI TTL Parallel Master Port address chip select 1 in.

CCP4 0O DIG CCP4 compare output and CCP4 PWM output; takes priority over port data.

1I ST CCP4 capture input.

P3D 0O DIG ECCP3 Enhanced PWM output, channel D; takes priority over port and

PMP data. May be configured for tri-state during Enhanced PWM

shutdown events.

RG4/PMCS2/

CCP5/P1D

RG4 0O DIG LATG<4> data output.

1I ST PORTG<4> data input.

PMCS2 xO DIG Parallel Master Port address chip select 2

CCP5 0O DIG CCP5 compare output and CCP5 PWM output; takes priority over port data.

1I ST CCP5 capture input.

P1D 0O DIG ECCP1 Enhanced PWM output, channel D; takes priority over port and

PMP data. May be configured for tri-state during Enhanced PWM

shutdown events.

Legend: O = Output, I = Input, DIG = Digital Output, ST = Schmitt Buffer Input, TTL = TTL Buffer Input,

x = Don’t care (TRIS bit does not affect port direction or is overridden for this option).

PIC18F87J50 FAMILY

TABLE 10-17: SUMMARY OF REGISTERS ASSOCIATED WITH PORTG

Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Reset

Values on

Page:

PORTG RDPU REPU RJPU(1) RG4 RG3 RG2 RG1 RG0 65

LATG — — — LATG4 LATG3 LATG2 LATG1 LATG0 64

TRISG — — — TRISG4 TRISG3 TRISG2 TRISG1 TRISG0 64

Legend: — = unimplemented, read as ‘0’. Shaded cells are not used by PORTG.

Note 1: Unimplemented on 64-pin devices, read as ‘0’.

PIC18F87J50 FAMILY

10.9 PORTH, LATH and

TRISH Registers

PORTH is an 8-bit wide, bidirectional I/O port. PORTH

pins <3:0> are digital only and tolerate voltages up to

5.5V.

All pins on PORTH are implemented with Schmitt

Trigger input buffers. Each pin is individually

configurable as an input or output.

When the external memory interface is enabled, four of

the PORTH pins function as the high-order address

lines for the interface. The address output from the

interface takes priority over other digital I/O. The

corresponding TRISH bits are also overridden. PORTH

pins, RH4 through RH7, are multiplexed with analog

converter inputs. The operation of these pins as analog

inputs is selected by clearing or setting the

corresponding bits in the ANCON1 register. RH3 to

RH6 is multiplexed with Parallel Master Port and RH4

to RH6 are multiplexed as comparator pins.

PORTH can also be configured as the alternate

Enhanced PWM output channels B and C for the

ECCP1 and ECCP3 modules. This is done by clearing

the ECCPMX Configuration bit.

EXAMPLE 10-8: INITIALIZING PORTH

Note: PORTH is available only on 80-pin

devices.

CLRF PORTH ; Initialize PORTH by

; clearing output

; data latches

CLRF LATH ; Alternate method to

; clear output latches

BSF WDTCON,ADSHR; Enable write/read to

; the shared SFR

MOVLW F0h ; Configure PORTH as

MOVWF ANCON1 ; digital I/O

BCF WDTCON,ADSHR; Disable write/read to

; the shared SFR

MOVLW 0CFh ; Value used to initialize

; data direction

MOVWF TRISH ; Set RH3:RH0 as inputs

; RH5:RH4 as outputs

; RH7:RH6 as inputs

PIC18F87J50 FAMILY

TABLE 10-18: PORTH FUNCTIONS

Pin Name Function TRIS

Setting I/O I/O

Type Description

RH0/A16 RH0 0O DIG LATH<0> data output.

1I ST PORTH<0> data input.

A16 xO DIG External memory interface, address line 16. Takes priority over port data.

RH1/A17 RH1 0O DIG LATH<1> data output.

1I ST PORTH<1> data input.

A17 xO DIG External memory interface, address line 17. Takes priority over port data.

RH2/A18/

PMD7

RH2 0O DIG LATH<2> data output.

1I ST PORTH<2> data input.

A18 xO DIG External memory interface, address line 18. Takes priority over port data.

PMD7(2) xO DIG Parallel Master Port data out.

xI TTL Parallel Master Port data input.

RH3/A19/

PMD6

RH3 0O DIG LATH<3> data output.

1I ST PORTH<3> data input.

A19 xO DIG External memory interface, address line 19. Takes priority over port data.

PMD6(2) xO DIG Parallel Master Port data out.

xI TTL Parallel Master Port data input.

RH4/PMD3/

AN12/P3C/

C2INC

RH4 0O DIG LATH<4> data output.

1I ST PORTH<4> data input.

PMD3(2) XI TTL Parallel Master Port data out.

XO DIG Parallel Master Port data input.

AN12 I ANA A/D input channel 12. Default input configuration on POR; does not affect

digital output.

P3C(1) 0O DIG ECCP3 Enhanced PWM output, channel C; takes priority over port and PMP

data. May be configured for tri-state during Enhanced PWM shutdown events.

C2INC xI ANA Comparator 2 input C.

RH5/PMBE/

AN13/P3B/

C2IND

RH5 0O DIG LATH<5> data output.

1I ST PORTH<5> data input.

PMBE(2) xO DIG Parallel Master Port Data byte enable.

AN13 I ANA A/D input channel 13. Default input configuration on POR; does not affect

digital output.

P3B(1) 0O DIG ECCP3 Enhanced PWM output, channel B; takes priority over port and PMP

data. May be configured for tri-state during Enhanced PWM shutdown events.

C2IND xI ANA Comparator 2 input D.

RH6/PMRD/

AN14/P1C/

C1INC

RH6 0O DIG LATH<6> data output.

1I ST PORTH<6> data input.

PMRD(2) xO DIG Parallel Master Port read strobe.

xI TTL Parallel Master Port read in.

AN14 I ANA A/D input channel 14. Default input configuration on POR; does not affect

digital output.

P1C(1) 0O DIG ECCP1 Enhanced PWM output, channel C; takes priority over port and PMP

data. May be configured for tri-state during Enhanced PWM shutdown events.

C1INC xI ANA Comparator 1 input C.

Legend: O = Output, I = Input, ANA = Analog Signal, DIG = Digital Output, ST = Schmitt Buffer Input,

TTL = TTL Buffer Input, x = Don’t care (TRIS bit does not affect port direction or is overridden for this option).

Note 1: Alternate assignments for P1B/P1C and P3B/P3C when ECCPMX Configuration bit is cleared. Default assignments are

PORTE<6:3>.

2: When PMPMX = 0.

PIC18F87J50 FAMILY

TABLE 10-19: SUMMARY OF REGISTERS ASSOCIATED WITH PORTH

RH7/PMWR/

AN15/P1B/

RH7 0O DIG LATH<7> data output.

1I ST PORTH<7> data input.

PMWR(2) xO DIG Parallel Master Port write strobe.

xI TTL Parallel Master Port write in.

AN15 I ANA A/D input channel 15. Default input configuration on POR; does not affect

digital output.

P1B(1) 0O DIG ECCP1 Enhanced PWM output, channel B; takes priority over port and PMP

data. May be configured for tri-state during Enhanced PWM shutdown events.

TABLE 10-18: PORTH FUNCTIONS (CONTINUED)

Pin Name Function TRIS

Setting I/O I/O

Type Description

Legend: O = Output, I = Input, ANA = Analog Signal, DIG = Digital Output, ST = Schmitt Buffer Input,

TTL = TTL Buffer Input, x = Don’t care (TRIS bit does not affect port direction or is overridden for this option).

Note 1: Alternate assignments for P1B/P1C and P3B/P3C when ECCPMX Configuration bit is cleared. Default assignments are

PORTE<6:3>.

2: When PMPMX = 0.

Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Reset

Values

on Page:

PORTH(1) RH7 RH6 RH5 RH4 RH3 RH2 RH1 RH0 64

LATH(1) LATH7 LATH6 LATH5 LATH4 LATH3 LATH2 LATH1 LATH0 65

TRISH(1) TRISH7 TRISH6 TRISH5 TRISH4 TRISH3 TRISH2 TRISH1 TRISH0 64

ANCON1(2) PCFG15 PCFG14 PCFG13 PCFG12 PCFG11 PCFG10 ——63

Legend: Shaded cells are not used by PORTH.

Note 1: Unimplemented on 64-pin devices, read as ‘0’.

2: Configuration SFR, overlaps with default SFR at this address; available only when WDTCON<4> = 1.

PIC18F87J50 FAMILY

10.10 PORTJ, TRISJ and

LATJ Registers

PORTJ is an 8-bit wide, bidirectional port. All pins on

PORTJ are digital only and tolerate voltages up to 5.5V.

All pins on PORTJ are implemented with Schmitt

Trigger input buffers. Each pin is individually

configurable as an input or output.

When the external memory interface is enabled, all of

the PORTJ pins function as control outputs for the

interface. This occurs automatically when the interface

is enabled by clearing the EBDIS control bit

(MEMCON<7>). The TRISJ bits are also overridden.

Each of the PORTJ pins has a weak internal pull-up.

The pull-ups are provided to keep the inputs at a known

state for the external memory interface while powering

up. A single control bit can turn off all the pull-ups. This

is performed by clearing bit RJPU (PORTG<5>). The

weak pull-up is automatically turned off when the port

pin is configured as an output. The pull-ups are

disabled on any device Reset.

EXAMPLE 10-9: INITIALIZING PORTJ

Note: PORTJ is available only on 80-pin devices.

Note: These pins are configured as digital inputs

on any device Reset.

CLRF PORTJ ; Initialize PORTG by

; clearing output

; data latches

CLRF LATJ ; Alternate method to clear

; output data latches

MOVLW 0CFh ; Value used to initialize

; data direction

MOVWF TRISJ ; Set RJ3:RJ0 as inputs

; RJ5:RJ4 as output

; RJ7:RJ6 as inputs

PIC18F87J50 FAMILY

TABLE 10-20: PORTJ FUNCTIONS

TABLE 10-21: SUMMARY OF REGISTERS ASSOCIATED WITH PORTJ

Pin Name Function TRIS

Setting I/O I/O

Type Description

RJ0/ALE RJ0 0O DIG LATJ<0> data output.

1I ST PORTJ<0> data input.

ALE xO DIG External memory interface address latch enable control output; takes

priority over digital I/O.

RJ1/OE RJ1 0O DIG LATJ<1> data output.

1I ST PORTJ<1> data input.

OE xO DIG External memory interface output enable control output; takes priority

over digital I/O.

RJ2/WRL RJ2 0O DIG LATJ<2> data output.

1I ST PORTJ<2> data input.

WRL xO DIG External Memory Bus write low byte control; takes priority over

digital I/O.

RJ3/WRH RJ3 0O DIG LATJ<3> data output.

1I ST PORTJ<3> data input.

WRH xO DIG External memory interface write high byte control output; takes priority

over digital I/O.

RJ4/BA0 RJ4 0O DIG LATJ<4> data output.

1I ST PORTJ<4> data input.

BA0 xO DIG External memory interface byte address 0 control output; takes priority

over digital I/O.

RJ5/CE RJ5 0O DIG LATJ<5> data output.

1I ST PORTJ<5> data input.

CE xO DIG External memory interface chip enable control output; takes priority

over digital I/O.

RJ6/LB RJ6 0O DIG LATJ<6> data output.

1I ST PORTJ<6> data input.

LB xO DIG External memory interface lower byte enable control output; takes

priority over digital I/O.

RJ7/UB RJ7 0O DIG LATJ<7> data output.

1I ST PORTJ<7> data input.

UB xO DIG External memory interface upper byte enable control output; takes

priority over digital I/O.

Legend: O = Output, I = Input, DIG = Digital Output, ST = Schmitt Buffer Input, TTL = TTL Buffer Input,

x = Don’t care (TRIS bit does not affect port direction or is overridden for this option).

Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Reset

Values

on Page:

PORTJ(1) RJ7 RJ6 RJ5 RJ4 RJ3 RJ2 RJ1 RJ0 65

LATJ(1) LATJ7 LATJ6 LATJ5 LATJ4 LATJ3 LATJ2 LATJ1 LATJ0 64

TRISJ(1) TRISJ7 TRISJ6 TRISJ5 TRISJ4 TRISJ3 TRISJ2 TRISJ1 TRISJ0 64

PORTG RDPU REPU RJPU(1) RG4 RG3 RG2 RG1 RG0 65

Legend: Shaded cells are not used by PORTJ.

Note 1: Unimplemented on 64-pin devices, read as ‘0’.

PIC18F87J50 FAMILY

NOTES:

PIC18F87J50 FAMILY

11.0 PARALLEL MASTER PORT

The Parallel Master Port module (PMP) is a parallel,

8-bit I/O module, specifically designed to communicate

with a wide variety of parallel devices, such as commu-

nication peripherals, LCDs, external memory devices

and microcontrollers. Because the interface to parallel

peripherals varies significantly, the PMP is highly

configurable. The PMP module can be configured to

serve as either a Parallel Master Port or as a Parallel

Slave Port.

Key features of the PMP module include:

• Up to 16 Programmable Address Lines

• Up to Two Chip Select Lines

• Programmable Strobe Options

- Individual Read and Write Strobes or;

- Read/Write Strobe with Enable Strobe

• Address Auto-Increment/Auto-Decrement

• Programmable Address/Data Multiplexing

• Programmable Polarity on Control Signals

• Legacy Parallel Slave Port Support

• Enhanced Parallel Slave Support

- Address Support

- 4-Byte Deep, Auto-Incrementing Buffer

• Programmable Wait States

• Selectable Input Voltage Levels

FIGURE 11-1: PMP MODULE OVERVIEW

PMA<0>

PMA<14>

PMA<15>

PMBE

PMRD

PMWR

PMD<7:0>

PMENB

PMRD/PMWR

PMCS1

PMA<1>

PMA<13:2>

PMALL

PMALH

PMA<7:0>

PMA<15:8>

PMCS2

EEPROM

Address Bus

Data Bus

Control Lines

PIC18

LCD FIFO

Microcontroller

8-Bit Data

Up to 16-Bit Address

Parallel Master Port

Buffer

PIC18F87J50 FAMILY

11.1 Module Registers

The PMP module has a total of 14 Special Function

Registers for its operation, plus one additional register

to set configuration options. Of these, 8 registers are

used for control and 6 are used for PMP data transfer.

11.1.1 CONTROL REGISTERS

The eight PMP Control registers are:

• PMCONH and PMCONL

• PMMODEH and PMMODEL

• PMSTATL and PMSTATH

• PMEH and PMEL

The PMCON registers (Register 11-1 and

ing turning the module on or off. They also configure

address multiplexing and control strobe configuration.

The PMMODE registers (Register 11-3 and

operating modes, the data width and interrupt

generation.

The PMEH and PMEL registers (Register 11-5 and

hardware (I/O pin) level.

The PMSTAT registers (Register 11-5 and

input and output buffers, depending on the operating

mode.

R/W-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

PMPEN — PSIDL

ADRMUX1 ADRMUX0

PTBEEN PTWREN PTRDEN

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 PMPEN: Parallel Master Port Enable bit

1 = PMP enabled

0 = PMP disabled, no off-chip access performed

bit 6 Unimplemented: Read as ‘0’

bit 5 PSIDL: Stop in Idle Mode bit

1 = Discontinue module operation when device enters Idle mode

0 = Continue module operation in Idle mode

bit 4-3 ADRMUX1:ADRMUX0: Address/Data Multiplexing Selection bits

11 = Reserved

10 = All 16 bits of address are multiplexed on PMD<7:0> pins

01 = Lower 8 bits of address are multiplexed on PMD<7:0> pins, upper 8 bits are on PMA<15:8>

00 = Address and data appear on separate pins

bit 2 PTBEEN: Byte Enable Port Enable bit (16-Bit Master mode)

1 = PMBE port enabled

0 = PMBE port disabled

bit 1 PTWREN: Write Enable Strobe Port Enable bit

1 = PMWR/PMENB port enabled

0 = PMWR/PMENB port disabled

bit 0 PTRDEN: Read/Write Strobe Port Enable bit

1 = PMRD/PMWR port enabled

0 = PMRD/PMWR port disabled

PIC18F87J50 FAMILY

R/W-0 R/W-0 R/W-0(1) R/W-0(1) R/W-0(1) R/W-0 R/W-0 R/W-0

CSF1 CSF0 ALP CS2P CS1P BEP WRSP RDSP

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7-6 CSF1:CSF0: Chip Select Function bits

11 = Reserved

10 = PMCS1 and PMCS2 function as chip select

01 = PMCS2 functions as chip select, PMCS1 used as address bit 14 (PMADDRH address bit 6)

00 = PMCS2 and PMCS1 used as address bits 15 and 14 (PMADDRH address bits 7 and 6)

bit 5 ALP: Address Latch Polarity bit(1)

1 = Active-high (PMALL and PMALH)

0 = Active-low (PMALL and PMALH)

bit 4 CS2P: Chip Select 2 Polarity bit(1)

1 = Active-high (PMCS2)

0 =Active-low (PMCS2

)

bit 3 CS1P: Chip Select 1 Polarity bit(1)

1 = Active-high (PMCS1/PMCS)

0 =Active-low (PMCS1

/PMCS)

bit 2 BEP: Byte Enable Polarity bit

1 = Byte enable active-high (PMBE)

0 = Byte enable active-low (PMBE)

bit 1 WRSP: Write Strobe Polarity bit

For Slave modes and Master Mode 2 (PMMODEH<1:0> = 00,01,10):

1 = Write strobe active-high (PMWR)

0 = Write strobe active-low (PMWR)

For Master Mode 1 (PMMODEH<1:0> = 11):

1 = Enable strobe active-high (PMENB)

0 = Enable strobe active-low (PMENB)

bit 0 RDSP: Read Strobe Polarity bit

For Slave modes and Master Mode 2 (PMMODEH<1:0> = 00,01,10):

1 = Read strobe active-high (PMRD)

0 = Read strobe active-low (PMRD)

For Master Mode 1 (PMMODEH<1:0> = 11):

1 = Read/write strobe active-high (PMRD/PMWR)

0 = Read/write strobe active-low (PMRD/PMWR)

Note 1: These bits have no effect when their corresponding pins are used as address lines.

PIC18F87J50 FAMILY

R-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

BUSY IRQM1 IRQM0 INCM1 INCM0 MODE16 MODE1 MODE0

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 BUSY: Busy bit (Master mode only)

1 = Port is busy

0 = Port is not busy

bit 6-5 IRQM1:IRQM0: Interrupt Request Mode bits

11 = Interrupt generated when read buffer 3 is read or write buffer 3 is written (Buffered PSP mode)

or on a read or write operation when PMA<1:0> = 11 (Addressable PSP mode only)

10 = No interrupt generated, processor stall activated

01 = Interrupt generated at the end of the read/write cycle

00 = No interrupt generated

bit 4-3 INCM1:INCM0: Increment Mode bits

11 = PSP read and write buffers auto-increment (Legacy PSP mode only)

10 = Decrement ADDR<15,13:0> by 1 every read/write cycle

01 = Increment ADDR<15,13:0> by 1 every read/write cycle

00 = No increment or decrement of address

bit 2 MODE16: 8/16-Bit Mode bit

1 = 16-Bit mode: data register is 16 bits, a read or write to the data register invokes two 8-bit transfers

0 = 8-Bit mode: data register is 8 bits, a read or write to the data register invokes one 8-bit transfer

bit 1-0 MODE1:MODE0: Parallel Port Mode Select bits

11 = Master Mode 1 (PMCSx, PMRD/PMWR, PMENB, PMBE, PMA<x:0> and PMD<7:0>)

10 = Master Mode 2 (PMCSx, PMRD, PMWR, PMBE, PMA<x:0> and PMD<7:0>)

01 = Enhanced PSP, control signals (PMRD, PMWR, PMCS, PMD<7:0> and PMA<1:0>)

00 = Legacy Parallel Slave Port, control signals (PMRD, PMWR, PMCS and PMD<7:0>)

PIC18F87J50 FAMILY

R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

WAITB1(1) WAITB0(1) WAITM3 WAITM2 WAITM1 WAITM0 WAITE1(1) WAITE0(1)

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7-6 WAITB1:WAITB0: Data Setup to Read/Write Wait State Configuration bits(1)

11 = Data wait of 4 TCY; multiplexed address phase of 4 TCY

10 = Data wait of 3 TCY; multiplexed address phase of 3 TCY

01 = Data wait of 2 TCY; multiplexed address phase of 2 TCY

00 = Data wait of 1 TCY; multiplexed address phase of 1 TCY

bit 5-2 WAITM3:WAITM0: Read to Byte Enable Strobe Wait State Configuration bits

1111 = Wait of additional 15 TCY

...

0001 = Wait of additional 1 T

0000 = No additional wait cycles (operation forced into one TCY)

bit 1-0 WAITE1:WAITE0: Data Hold After Strobe Wait State Configuration bits(1)

11 = Wait of 4 TCY

10 = Wait of 3 TCY

01 = Wait of 2 TCY

00 = Wait of 1 TCY

Note 1: WAITB and WAITE bits are ignored whenever WAITM3:WAITM0 = 0000.

R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

PTEN15 PTEN14 PTEN13 PTEN12 PTEN11 PTEN10 PTEN9 PTEN8

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7-6 PTEN15:PTEN14: PMCSx Strobe Enable bits

1 = PMA15 and PMA14 function as either PMA<15:14> or PMCS2 and PMCS1

0 = PMA15 and PMA14 function as port I/O

bit 5-0 PTEN13:PTEN8: PMP Address Port Enable bits

1 = PMA<13:8> function as PMP address lines

0 = PMA<13:8> function as port I/O

PIC18F87J50 FAMILY

R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

PTEN7 PTEN6 PTEN5 PTEN4 PTEN3 PTEN2 PTEN1 PTEN0

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7-2 PTEN7:PTEN2: PMP Address Port Enable bits

1 = PMA<7:2> function as PMP address lines

0 = PMA<7:2> function as port I/O

bit 1-0 PTEN1:PTEN0: PMALH/PMALL Strobe Enable bits

1 = PMA1 and PMA0 function as either PMA<1:0> or PMALH and PMALL

0 = PMA1 and PMA0 pads functions as port I/O

R-0 R/W-0 U-0 U-0 R-0 R-0 R-0 R-0

IBF IBOV —— IB3F IB2F IB1F IB0F

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 IBF: Input Buffer Full Status bit

1 = All writable input buffer registers are full

0 = Some or all of the writable input buffer registers are empty

bit 6 IBOV: Input Buffer Overflow Status bit

1 = A write attempt to a full input byte register occurred (must be cleared in software)

0 = No overflow occurred

bit 5-4 Unimplemented: Read as ‘0’

bit 3-0 IB3F:IB0F: Input Buffer x Status Full bits

1 = Input buffer contains data that has not been read (reading buffer will clear this bit)

0 = Input buffer does not contain any unread data

PIC18F87J50 FAMILY

R-1 R/W-0 U-0 U-0 R-1 R-1 R-1 R-1

OBE OBUF —— OB3E OB2E OB1E OB0E

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 OBE: Output Buffer Empty Status bit

1 = All readable output buffer registers are empty

0 = Some or all of the readable output buffer registers are full

bit 6 OBUF: Output Buffer Underflow Status bit

1 = A read occurred from an empty output byte register (must be cleared in software)

0 = No underflow occurred

bit 5-4 Unimplemented: Read as ‘0’

bit 3-0 OB3E:OB0E: Output Buffer x Status Empty bits

1 = Output buffer is empty (writing data to the buffer will clear this bit)

0 = Output buffer contains data that has not been transmitted

PIC18F87J50 FAMILY

11.1.2 DATA REGISTERS

The PMP module uses 6 registers for transferring data

into and out of the microcontroller. They are arranged

as three pairs to allow the option of 16-bit data

operations:

• PMDIN1H and PMDIN1L

• PMDIN2H and PMDIN2L

• PMADDRH/PMDOUT1H and PMADDRL/PMDOUT1L

• PMDOUT2H and PMDOUT2L

The PMDIN1 register is used for incoming data in Slave

modes, and both input and output data in Master

modes. The PMDIN2 register is used for buffering input

data in select Slave modes.

The PMADDRx/PMDOUT1x registers are actually a

single register pair; the name and function is dictated

by the module’s operating mode. In Master modes, the

registers functions as the PMADDRH and PMADDRL

registers, and contain the address of any incoming or

outgoing data. In Slave modes, the registers function

as PMDOUT1H and PMDOUT1L and are used for

outgoing data.

PMADDRH differs from PMADDRL in that it can also

have limited PMP control functions. When the module

is operating in select Master mode configurations, the

upper two bits of the register can be used to determine

the operation of chip select signals. If chip select

signals are not used, PMADDR simply functions to hold

the upper 8 bits of the address. The function of the

individual bits in PMADDRH is shown in Register 11-9.

The PMDOUT2H and PMDOUT2L registers are only

used in Buffered Slave modes and serve as a buffer for

outgoing data.

11.1.3 PAD CONFIGURATION CONTROL

In addition to the module level configuration options,

the PMP module can also be configured at the I/O pin

for electrical operation. This option allows users to

select either the normal Schmitt Trigger input buffer on

digital I/O pins shared with the PMP, or use TTL level

compatible buffers instead. Buffer configuration is

controlled by the PMPTTL bit in the PADCFG1 register.

The PADCFG1 register is one of the shared address

SFRs, and has the same address as the TMR2 regis-

ter. PADCFG1 is accessed by setting the ADSHR bit

(WDTCON<4>). Refer to Section 5.3.5.1 “Shared

Address SFRs” for more information.

HIGH BYTE (MASTER MODES ONLY)(1)

R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

CS2 CS1 ADDR<13:8>

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 CS2: Chip Select 2 bit

If PMCON<7:6> = 10 or 01:

1 = Chip select 2 is active

0 = Chip select 2 is inactive

If PMCON<7:6> = 11 or 00:

Bit functions as ADDR<15>.

bit 6 CS1: Chip Select 1 bit

If PMCON<7:6> = 10:

1 = Chip select 1 is active

0 = Chip select 1 is inactive

If PMCON<7:6> = 11 or 0x:

Bit functions as ADDR<14>.

bit 5-0 ADDR5:ADDR0: Parallel Port Destination Address bits

Note 1: In Enhanced Slave mode, PMADDRH functions as PMDOUT1H, one of the Output Data Buffer registers.

PIC18F87J50 FAMILY

11.1.4 PMP MULTIPLEXING

OPTIONS(80-PINS DEVICES)

By default, the PMP and the External Memory Bus

(EMB) multiplex some of their signals to the same I/O

pins on PORTD and PORTE. It is possible that some

applications may require the use of both modules at the

same time. For these instances, the 80-pin devices can

be configured to multiplex the PMP to different I/O

ports. PMP configuration is determined by the PMPMX

Configuration bit setting; by default, the PMP and EMB

modules share PORTD and PORTE. The optional pin

configuration is shown in Table 11-1.

TABLE 11-1: PMP PIN MULTIPLEXING

80-PIN DEVICES

11.2 Slave Port Modes

The primary mode of operation for the module is con-

figured using the MODE1:MODE0 bits in the

PMMODEH register. The setting affects whether the

module acts as a slave or a master and it determines

the usage of the control pins.

11.2.1 LEGACY MODE (PSP)

In Legacy mode (PMMODEH<1:0> = 00 and

PMPEN = 1), the module is configured as a Parallel

Slave Port with the associated enabled module pins

dedicated to the module. In this mode, an external

device, such as another microcontroller or micro-

processor, can asynchronously read and write data

using the 8-bit data bus (PMD<7:0>), the read (PMRD),

write (PMWR) and chip select (PMCS1) inputs. It acts

as a slave on the bus and responds to the read/write

control signals.

Figure 11-2 shows the connection of the Parallel Slave

Port. When chip select is active and a write strobe

occurs (PMCS = 1 and PMWR = 1), the data from

PMD<7:0> is captured into the PMDIN1L register.

FIGURE 11-2: LEGACY PARALLEL SLAVE PORT EXAMPLE

PMP

Function

Pin Assignment

PMPMX = 1PMPMX= 0

PMD0 PORTD<0> PORTF<7>

PMD1 PORTD<1> PORTF<6>

PMD2 PORTD<2> PORTF<5>

PMD3 PORTD<3> PORTH<4>

PMD4 PORTD<4> PORTA<5>

PMD5 PORTD<5> PORTA<4>

PMD6 PORTD<6> PORTH<3>

PMD7 PORTD<7> PORTH<2>

PMBE PORTE<2> PORTH<5>

PMWR PORTE<1> PORTH<7>

PMRD PORTE<0> PORTH<6>

PMD<7:0>

PMRD

PMWR

Master Address Bus

Data Bus

Control Lines

PMCS

PMD<7:0>

PMRD

PMWR

PIC18 Slave

PMCS1

PIC18F87J50 FAMILY

11.2.2 WRITE TO SLAVE PORT

When chip select is active and a write strobe occurs

(PMCS = 1 and PMWR = 1), the data from PMD<7:0>

is captured into the lower PMDIN1L register. The

PMPIF and IBF flag bits are set when the write

ends.The timing for the control signals in Write mode is

shown in Figure 11-3. The polarity of the control signals

are configurable.

11.2.3 READ FROM SLAVE PORT

When chip select is active and a read strobe occurs

(PMCS = 1 and PMRD = 1), the data from the

PMDOUTL1 register (PMDOUTL1<7:0>) is presented

onto PMD<7:0>.The timing for the control signals in

Read mode is shown in Figure 11-4.

FIGURE 11-3: PARALLEL SLAVE PORT WRITE WAVEFORMS

FIGURE 11-4: PARALLEL SLAVE PORT READ WAVEFORMS

PMCS1

| Q4 | Q1 | Q2 | Q3 | Q4

PMWR

PMRD

PMD<7:0>

IBF

OBE

PMPIF

PMCS1

| Q4 | Q1 | Q2 | Q3 | Q4

PMWR

PMRD

PMD<7:0>

IBF

OBE

PMPIF

PIC18F87J50 FAMILY

11.2.4 BUFFERED PARALLEL SLAVE

PORT MODE

Buffered Parallel Slave Port mode is functionally iden-

tical to the legacy Parallel Slave Port mode with one

exception: the implementation of 4-level read and write

buffers. Buffered PSP mode is enabled by setting the

INCM bits in the PMMODEH register. If the INCM<1:0>

bits are set to ‘11’, the PMP module will act as the

buffered Parallel Slave Port.

When the Buffered mode is active, the PMDIN1L,

PMDIN1H, PMDIN2L and PMDIN2H registers become

the write buffers and the PMDOUT1L, PMDOUT1H,

PMDOUT2L and PMDOUT2H registers become the

read buffers. Buffers are numbered 0 through 3, start-

ing with the lower byte of PMDIN1L to PMDIN2H as the

read buffers and PMDOUT1L to PMDOUT2H as the

write buffers.

11.2.4.1 READ FROM SLAVE PORT

For read operations, the bytes will be sent out sequen-

tially, starting with Buffer 0 (PMDOUT1L<7:0>) and

ending with Buffer 3 (PMDOUT2H<7:0>) for every read

strobe. The module maintains an internal pointer to

keep track of which buffer is to be read. Each of the

buffers has a corresponding read status bit, OBxE, in

the PMSTATL register. This bit is cleared when a buffer

contains data that has not been written to the bus, and

is set when data is written to the bus. If the current

buffer location being read from is empty, a buffer under-

flow is generated, and the Buffer Overflow flag bit

OBUF is set. If all four OBxE status bits are set, then

the Output Buffer Empty flag (OBE) will also be set.

11.2.4.2 WRITE TO SLAVE PORT

For write operations, the data is be stored sequentially,

starting with Buffer 0 (PMDIN1L<7:0>) and ending with

Buffer 3 (PMDIN2H<7:0). As with read operations, the

module maintains an internal pointer to the buffer that

is to be written next.

The input buffers have their own write status bits, IBxF

in the PMSTATH register. The bit is set when the buffer

contains unread incoming data, and cleared when the

data has been read. The flag bit is set on the write

strobe. If a write occurs on a buffer when its associated

IBxF bit is set, the Buffer Overflow flag, IBOV, is set;

any incoming data in the buffer will be lost. If all four

IBxF flags are set, the Input Buffer Full Flag (IBF) is set.

In Buffered Slave mode, the module can be configured

to generate an interrupt on every read or write strobe

(IRQM1:IRQM0 = 01). It can be configured to generate

an interrupt on a read from Read Buffer 3 or a write to

Write Buffer 3, which is essentially an interrupt every

fourth read or write strobe (RQM1:IRQM0 = 11). When

interrupting every fourth byte for input data, all input

buffer registers should be read to clear the IBxF flags.

If these flags are not cleared, then there is a risk of

hitting an overflow condition.

FIGURE 11-5: PARALLEL MASTER/SLAVE CONNECTION BUFFERED EXAMPLE

PMD<7:0>

PMRD

PMWR

PMCS

Data Bus

Control Lines

PMRD

PMWR

PIC18 Slave

PMCS1

PMDOUT1L (0)

PMDOUT1H (1)

PMDOUT2L (2)

PMDOUT2H (3)

PMDIN1L (0)

PMDIN1H (1)

PMDIN2L (2)

PMDIN2H (3)

PMD<7:0> Write

Address

Pointer

Read

Address

Pointer

Master

PIC18F87J50 FAMILY

11.2.5 ADDRESSABLE PARALLEL SLAVE

PORT MODE

In the Addressable Parallel Slave Port mode

(PMMODEH<1:0> = 01), the module is configured with

two extra inputs, PMA<1:0>, which are the address

lines 1 and 0. This makes the 4-byte buffer space

directly addressable as fixed pairs of read and write

buffers. As with legacy Buffered mode, data is output

from PMDOUT1L, PMDOUT1H, PMDOUT2L and

PMDOUT2H, and is read in PMDIN1L, PMDIN1H,

PMDIN2L and PMDIN2H. Table 11-2 shows the buffer

addressing for the incoming address to the input and

output registers.

TABLE 11-2: SLAVE MODE BUFFER

ADDRESSING

FIGURE 11-6: PARALLEL MASTER/SLAVE CONNECTION ADDRESSED BUFFER EXAMPLE

PMADDR<1:0>

Output

(Buffer)

Input Register

(Buffer)

00 PMDOUT1L (0) PMDIN1L (0)

01 PMDOUT1H (1) PMDIN1H (1)

10 PMDOUT2L (2) PMDIN2L (2)

11 PMDOUT2H((3) PMDIN2H (3)

PMD<7:0>

PMRD

PMWR

Master

PMCS

PMA<1:0>

Address Bus

Data Bus

Control Lines

PMRD

PMWR

PIC18F Slave

PMCS1

PMDOUT1L (0)

PMDOUT1H (1)

PMDOUT2L (2)

PMDOUT2H (3)

PMDIN1L (0)

PMDIN1H (1)

PMDIN2L (2)

PMDIN2H (3)

PMD<7:0> Write

Address

Decode

Read

Address

Decode

PMA<1:0>

PIC18F87J50 FAMILY

11.2.5.1 READ FROM SLAVE PORT

When chip select is active and a read strobe occurs

(PMCS = 1 and PMRD = 1), the data from one of the

four output bytes is presented onto PMD<7:0>. Which

byte is read depends on the 2-bit address placed on

ADDR[1:0]. Table 11-2 shows the corresponding

output registers and their associated address. When an

output buffer is read, the corresponding OBxE bit is set.

The OBxE flag bit is set when all the buffers are empty.

If any buffer is already empty, OBxE = 1, the next read

to that buffer will generate an OBUF event.

FIGURE 11-7: PARALLEL SLAVE PORT READ WAVEFORMS

11.2.5.2 WRITE TO SLAVE PORT

When chip select is active and a write strobe occurs

(PMCS = 1 and PMWR = 1), the data from PMD<7:0>

is captured into one of the four input buffer bytes.

Which byte is written depends on the 2-bit address

placed on ADDRL[1:0]. Table 11-2 shows the corre-

sponding input registers and their associated address.

When an input buffer is written, the corresponding IBxF

bit is set. The IBF flag bit is set when all the buffers are

written. If any buffer is already written (IBxF = 1), the

next write strobe to that buffer will generate an OBUF

event and the byte will be discarded.

FIGURE 11-8: PARALLEL SLAVE PORT WRITE WAVEFORMS

PMCS

| Q4 | Q1 | Q2 | Q3 | Q4

PMWR

PMRD

PMD<7:0>

PMA<1:0>

OBE

PMPIF

PMCS

| Q4 | Q1 | Q2 | Q3 | Q4

PMWR

PMRD

PMD<7:0>

IBF

PMPIF

PMA<1:0>

PIC18F87J50 FAMILY

11.3 MASTER PORT MODES

In its Master modes, the PMP module provides an 8-bit

data bus, up to 16 bits of address, and all the necessary

control signals to operate a variety of external parallel

devices, such as memory devices, peripherals and

slave microcontrollers. To use the PMP as a master,

the module must be enabled (PMPEN = 1) and the

mode must be set to one of the two possible Master

modes (PMMODEH<1:0> = 10 or 11).

Because there are a number of parallel devices with a

variety of control methods, the PMP module is

designed to be extremely flexible to accommodate a

range of configurations. Some of these features

include:

• 8 and 16-Bit Data modes on an 8-bit data bus

• Configurable address/data multiplexing

• Up to two chip select lines

• Up to 16 selectable address lines

• Address auto-increment and auto-decrement

• Selectable polarity on all control lines

• Configurable wait states at different stages of the

read/write cycle

11.3.1 PMP AND I/O PIN CONTROL

Multiple control bits are used to configure the presence

or absence of control and address signals in the mod-

ule. These bits are PTBEEN, PTWREN, PTRDEN, and

PTEN<15:0>. They give the user the ability to conserve

pins for other functions and allow flexibility to control

the external address. When any one of these bits is set,

the associated function is present on its associated pin;

when clear, the associated pin reverts to its defined I/O

port function.

Setting a PTEN bit will enable the associated pin as an

address pin and drive the corresponding data con-

tained in the PMADDR register. Clearing the PTENx bit

will force the pin to revert to its original I/O function.

For the pins configured as chip select (PMCS1 or

PMCS2) with the corresponding PTENx bit set. The

PTEN0 and PTEN1 bits also control the PMALL and

PMALH signals. When multiplexing is used, the

associated address latch signals should be enabled.

11.3.2 READ/WRITE CONTROL

The PMP module supports two distinct read/write

signaling methods. In Master Mode 1, read and write

strobe are combined into a single control line,

PMRD/PMWR. A second control line, PMENB, deter-

mines when a read or write action is to be taken. In

Master Mode 2, separate Read and Write strobes

(PMRD and PMWR) are supplied on separate pins.

All control signals (PMRD, PMWR, PMBE, PMENB,

PMAL and PMCSx) can be individually configured as

either positive or negative polarity. Configuration is

controlled by separate bits in the PMCONL register.

Note that the polarity of control signals that share the

same output pin (for example, PMWR and PMENB) are

controlled by the same bit; the configuration depends

on which Master Port mode is being used.

11.3.3 DATA WIDTH

The PMP supports data widths of both 8 and 16 bits.

The data width is selected by the MODE16 bit

(PMMODEH<2>). Because the data path into and out

of the module is only 8 bits wide, 16-bit operations are

always handled in a multiplexed fashion, with the Least

Significant Byte of data being presented first. To differ-

entiate data bytes, the Byte Enable control strobe,

PMBE, is used to signal when the Most Significant Byte

of data is being presented on the data lines.

11.3.4 ADDRESS MULTIPLEXING

In either of the Master modes (PMMODEH<1:0> = 1x),

the user can configure the address bus to be multiplexed

together with the data bus. This is accomplished using

the ADRMUX1:ADRMUX0 bits (PMCONH<4:3>). There

are three address multiplexing modes available; typical

pinout configurations for these modes are shown in

Figure 11-9, Figure 11-10 and Figure 11-11.

In Demultiplexed mode (PMCONH<4:3> = 00), data

and address information are completely separated.

Data bits are presented on PMD<7:0>, and address

bits are presented on PMADDRH<7:0> and

PMADDRL<7:0>

In Partially Multiplexed mode (PMCONH<4:3> = 01),

the lower eight bits of the address are multiplexed with

the data pins on PMD<7:0>. The upper eight bits of

address are unaffected and are presented on

PMADDRH<7:0>. The PMA0 pin is used as an

Address Latch, and presents the Address Latch Low

enable strobe (PMALL). The read and write sequences

are extended by a complete CPU cycle during which

the address is presented on the PMD<7:0> pins.

In Fully Multiplexed mode (PMCONH<4:3> = 10), the

entire 16 bits of the address are multiplexed with the

data pins on PMD<7:0>. The PMA0 and PMA1 pins are

used to present Address Latch Low enable (PMALL)

and Address Latch High enable (PMALH) strobes,

respectively. The read and write sequences are

extended by two complete CPU cycles. During the first

cycle, the lower eight bits of the address are presented

on the PMD<7:0> pins with the PMALL strobe active.

During the second cycle, the upper eight bits of the

address are presented on the PMD<7:0> pins with the

PMALH strobe active. In the event the upper address

bits are configured as chip select pins, the

corresponding address bits are automatically forced

to ‘0’.

PIC18F87J50 FAMILY

FIGURE 11-9: DEMULTIPLEXED ADDRESSING MODE (SEPARATE READ AND WRITE

STROBES, TWO CHIP SELECTS)

FIGURE 11-10: PARTIALLY MULTIPLEXED ADDRESSING MODE (SEPARATE READ AND

WRITE STROBES, TWO CHIP SELECTS)

FIGURE 11-11: FULLY MULTIPLEXED ADDRESSING MODE (SEPARATE READ AND WRITE

STROBES, TWO CHIP SELECTS)

PMRD

PMWR

PMD<7:0>

PMCS1

PMA<13:0>

PMCS2

PIC18F

Address Bus

Data Bus

Control Lines

PMRD

PMWR

PMD<7:0>

PMCS1

PMA<13:8>

PMALL

PMA<7:0>

PMCS2

PIC18F

Address Bus

Multiplexed

Data and

Address Bus

Control Lines

PMRD

PMWR

PMD<7:0>

PMCS1

PMALH

PMA<13:8>

PMCS2

PIC18F

Multiplexed

Data and

Address Bus

Control Lines

PMALL

PIC18F87J50 FAMILY

11.3.5 CHIP SELECT FEATURES

Up to two chip select lines, PMCS1 and PMCS2, are

available for the Master modes of the PMP. The two

chip select lines are multiplexed with the Most Signifi-

cant bits of the address bus (PMADDRH<6> and

PMADDRH<7>). When a pin is configured as a chip

select, it is not included in any address auto-increment/

decrement. The function of the chip select signals is

configured using the chip select function bits

(PMCONL<7:6>).

11.3.6 AUTO-INCREMENT/DECREMENT

While the module is operating in one of the Master

modes, the INCM bits (PMMODEH<3:4>) control the

behavior of the address value. The address can be

made to automatically increment or decrement after

each read and write operation. The address increments

once each operation is completed and the BUSY bit

goes to ‘0’. If the chip select signals are disabled and

configured as address bits, the bits will participate in

the increment and decrement operations; otherwise,

the CS2 and CS1 bit values will be unaffected.

11.3.7 WAIT STATES

In Master mode, the user has control over the duration

of the read, write and address cycles by configuring the

module wait states. Three portions of the cycle, the

beginning, middle and end, are configured using the

corresponding WAITBx, WAITMx and WAITEx bits in

the PMMODEL register.

The WAITB bits (PMMODEL<7:6>) set the number of

wait cycles for the data setup prior to the PMRD/PMWT

strobe in Mode 10, or prior to the PMENB strobe in

Mode 11. The WAITM bits (PMMODEL<5:2>) set the

number of wait cycles for the PMRD/PMWT strobe in

Mode 10, or for the PMENB strobe in Mode 11. When

this wait state setting is 0 then WAITB and WAITE have

no effect. The WAITE bits (PMMODEL<1:0>) define

the number of wait cycles for the data hold time after

the PMRD/PMWT strobe in Mode 10, or after the

PMENB strobe in Mode 11.

11.3.8 READ OPERATION

To perform a read on the Parallel Master Port, the user

reads the PMDIN1L register. This causes the PMP to

output the desired values on the chip select lines and

the address bus. Then the read line (PMRD) is strobed.

The read data is placed into the PMDIN1L register.

If the 16-bit mode is enabled (MODE16 = 1), the read

of the low byte of the PMDIN1L register will initiate two

bus reads. The first read data byte is placed into the

PMDIN1L register, and the second read data is placed

into the PMDIN1H.

Note that the read data obtained from the PMDIN1L

read operation. Hence, the first user read will be a

dummy read to initiate the first bus read and fill the read

ready until after the BUSY bit is observed low. Thus, in

a back-to-back read operation, the data read from the

of the register will yield the new value.

11.3.9 WRITE OPERATION

To perform a write onto the parallel bus, the user writes

to the PMDIN1L register. This causes the module to

first output the desired values on the chip select lines

and the address bus. The write data from the PMDIN1L

the write line (PMWR) is strobed. If the 16-bit mode is

enabled (MODE16 = 1), the write to the PMDIN1L reg-

ister will initiate two bus writes. First write will consist of

the data contained in PMDIN1L and the second write

will contain the PMDIN1H.

11.3.10 PARALLEL MASTER PORT STATUS

11.3.10.1 The BUSY Bit

In addition to the PMP interrupt, a BUSY bit is provided

to indicate the status of the module. This bit is only

used in Master mode. While any read or write operation

is in progress, the BUSY bit is set for all but the very last

CPU cycle of the operation. In effect, if a single-cycle

read or write operation is requested, the BUSY bit will

never be active. This allows back-to-back transfers.

While the bit is set, any request by the user to initiate a

new operation will be ignored (i.e., writing or reading

the lower byte of the PMDIN1L register will not initiate

either a read nor a write).

11.3.10.2 INTERRUPTS

When the PMP module interrupt is enabled for Master

mode, the module will interrupt on every completed

read or write cycle; otherwise, the BUSY bit is available

to query the status of the module.

PIC18F87J50 FAMILY

11.3.11 MASTER MODE TIMING

This section contains a number of timing examples that

represent the common Master mode configuration

options. These options vary from 8-bit to 16-bit data,

fully demultiplexed to fully multiplexed address, as well

as wait states.

FIGURE 11-12: READ AND WRITE TIMING, 8-BIT DATA, DEMULTIPLEXED ADDRESS

FIGURE 11-13: READ TIMING, 8-BIT DATA, PARTIALLY MULTIPLEXED ADDRESS

FIGURE 11-14: READ TIMING, 8-BIT DATA, WAIT STATES ENABLED,

PARTIALLY MULTIPLEXED ADDRESS

PMCS2

PMWR

PMRD

PMPIF

PMD<7:0>

PMCS1

PMA<13:0>

Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1

BUSY

Q2 Q3 Q4Q1

PMCS2

PMWR

PMRD

PMALL

PMD<7:0>

PMCS1

PMA<13:8>

Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1

PMPIF

BUSY

Address<7:0> Data

PMCS2

PMRD

PMWR

PMALL

PMD<7:0>

PMCS1

PMA<13:8>

Q1- - -

PMPIF

Q1- - - Q1- - - Q1- - - Q1- - - Q1- - - Q1- - - Q1- - - Q1- - - Q1- - - Q1- - - Q1- - - Q1- - - Q1- - -

WAITM<3:0> = 0010

WAITE<1:0> = 00

WAITB<1:0> = 01

BUSY

Address<7:0> Data

PIC18F87J50 FAMILY

FIGURE 11-15: WRITE TIMING, 8-BIT DATA, PARTIALLY MULTIPLEXED ADDRESS

FIGURE 11-16: WRITE TIMING, 8-BIT DATA, WAIT STATES ENABLED,

PARTIALLY MULTIPLEXED ADDRESS

FIGURE 11-17: READ TIMING, 8-BIT DATA, PARTIALLY MULTIPLEXED ADDRESS,

ENABLE STROBE

PMCS2

PMWR

PMRD

PMALL

PMD<7:0>

PMCS1

PMA<13:8>

Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1

PMPIF

Data

BUSY

Address<7:0>

PMCS2

PMWR

PMRD

PMALL

PMD<7:0>

PMCS1

PMA<13:8>

Q1- - -

PMPIF

Data

Q1- - - Q1- - - Q1- - - Q1- - - Q1- - - Q1- - - Q1- - - Q1- - - Q1- - - Q1- - - Q1- - - Q1- - - Q1- - -

WAITM<3:0> = 0010

WAITE<1:0> = 00

WAITB<1:0> = 01

BUSY

Address<7:0>

PMCS2

PMRD/PMWR

PMENB

PMALL

PMD<7:0>

PMCS1

PMA<13:8>

Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1

PMPIF

BUSY

Address<7:0> Data

PIC18F87J50 FAMILY

FIGURE 11-18: WRITE TIMING, 8-BIT DATA, PARTIALLY MULTIPLEXED ADDRESS,

ENABLE STROBE

FIGURE 11-19: READ TIMING, 8-BIT DATA, FULLY MULTIPLEXED 16-BIT ADDRESS

FIGURE 11-20: WRITE TIMING, 8-BIT DATA, FULLY MULTIPLEXED 16-BIT ADDRESS

PMCS2

PMRD/PMWR

PMENB

PMALL

PMD<7:0>

PMCS1

PMA<13:8>

Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1

PMPIF

Data

BUSY

Address<7:0>

PMCS2

PMWR

PMRD

PMALL

PMD<7:0>

PMCS1

Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1

PMALH

Data

PMPIF

BUSY

Address<7:0> Address<15:8>

PMCS2

PMWR

PMRD

PMALL

PMD<7:0>

PMCS1

Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1

PMALH

Data

PMPIF

BUSY

Address<7:0> Address<15:8>

PIC18F87J50 FAMILY

FIGURE 11-21: READ TIMING, 16-BIT DATA, DEMULTIPLEXED ADDRESS

FIGURE 11-22: WRITE TIMING, 16-BIT DATA, DEMULTIPLEXED ADDRESS

FIGURE 11-23: READ TIMING, 16-BIT MULTIPLEXED DATA,

PARTIALLY MULTIPLEXED ADDRESS

PMCS2

PMWR

PMRD

PMD<7:0>

PMCS1

PMA<13:0>

Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1

PMPIF

PMBE

BUSY

MSBLSB

PMCS2

PMWR

PMRD

PMD<7:0>

PMCS1

PMA<13:0>

Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1

PMPIF

LSB MSB

PMBE

BUSY

PMCS2

PMWR

PMRD

PMALL

PMD<7:0>

PMCS1

PMA<13:8>

Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1

PMPIF

PMBE

BUSY

Address<7:0> LSB MSB

PIC18F87J50 FAMILY

FIGURE 11-24: WRITE TIMING, 16-BIT MULTIPLEXED DATA,

PARTIALLY MULTIPLEXED ADDRESS

FIGURE 11-25: READ TIMING, 16-BIT MULTIPLEXED DATA,

FULLY MULTIPLEXED 16-BIT ADDRESS

FIGURE 11-26: WRITE TIMING, 16-BIT MULTIPLEXED DATA,

FULLY MULTIPLEXED 16-BIT ADDRESS

PMCS2

PMWR

PMRD

PMALL

PMD<7:0>

PMCS1

PMA<13:8>

Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1

PMPIF

LSB MSB

PMBE

BUSY

Address<7:0>

PMCS2

PMWR

PMRD

PMBE

PMD<7:0>

PMCS1

Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1

PMALH

PMPIF

PMALL

BUSY

Q2 Q3 Q4Q1

Address<7:0> LSBAddress<15:8> MSB

PMCS2

PMWR

PMRD

PMBE

PMD<7:0>

PMCS1

Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1

PMALH

PMALL

MSBLSB

PMPIF

BUSY

Q2 Q3 Q4Q1

Address<7:0> Address<15:8>

PIC18F87J50 FAMILY

11.4 Application Examples

This section introduces some potential applications for

the PMP module.

11.4.1 MULTIPLEXED MEMORY OR

PERIPHERAL

Figure 11-27 demonstrates the hookup of a memory or

another addressable peripheral in Full Multiplex mode.

Consequently, this mode achieves the best pin saving

from the microcontroller perspective. However, for this

configuration, there needs to be some external latches

to maintain the address.

FIGURE 11-27: EXAMPLE OF A MULTIPLEXED ADDRESSING APPLICATION

11.4.2 PARTIALLY MULTIPLEXED

MEMORY OR PERIPHERAL

Partial multiplexing implies using more pins; however,

for a few extra pins, some extra performance can be

achieved. Figure 11-28 shows an example of a mem-

ory or peripheral that is partially multiplexed with an

external latch. If the peripheral has internal latches, as

shown in Figure 11-29, then no extra circuitry is

required except for the peripheral itself.

FIGURE 11-28: EXAMPLE OF A PARTIALLY MULTIPLEXED ADDRESSING APPLICATION

FIGURE 11-29: EXAMPLE OF AN 8-BIT MULTIPLEXED ADDRESS AND DATA APPLICATION

PMD<7:0>

PMALH

D<7:0>

373 A<15:0>

D<7:0>

A<7:0>

373

PMRD

PMWR

OE WR

PIC18F

Address Bus

Data Bus

Control Lines

PMCS

PMALL

A<15:8>

PMA<14:7>

D<7:0>

373 A<14:0>

D<7:0>

A<7:0>

PMRD

PMWR

OE WR

PIC18F

Address Bus

Data Bus

Control Lines

PMCS

PMALL

A<14:8>

PMD<7:0>

ALE

PMRD

PMWR

PIC18F

Address Bus

Data Bus

Control Lines

PMCS

PMALL

AD<7:0>

Parallel Peripheral

PMD<7:0>

PIC18F87J50 FAMILY

11.4.3 PARALLEL EEPROM EXAMPLE

Figure 11-30 shows an example connecting parallel

EEPROM to the PMP. Figure 11-31 shows a slight

variation to this, configuring the connection for 16-bit

data from a single EEPROM.

FIGURE 11-30: PARALLEL EEPROM EXAMPLE (UP TO 15-BIT ADDRESS, 8-BIT DATA)

FIGURE 11-31: PARALLEL EEPROM EXAMPLE (UP TO 15-BIT ADDRESS, 16-BIT DATA)

11.4.4 LCD CONTROLLER EXAMPLE

The PMP module can be configured to connect to a

typical LCD controller interface, as shown in

Figure 11-32. In this case the PMP module is config-

ured for active-high control signals since common LCD

displays require active-high control.

FIGURE 11-32: LCD CONTROL EXAMPLE (BYTE MODE OPERATION)

PMA<n:0> A<n:0>

D<7:0>

PMRD

PMWR

PIC18F

Address Bus

Data Bus

Control Lines

PMCS

PMD<7:0>

Parallel EEPROM

PMA<n:0> A<n:1>

D<7:0>

PMRD

PMWR

PIC18F

Address Bus

Data Bus

Control Lines

PMCS

PMD<7:0>

Parallel EEPROM

PMBE A0

PMRD/PMWR

D<7:0>

PIC18F

Address Bus

Data Bus

Control Lines

PMA0

R/W

LCD Controller

PMCS

PM<7:0>

PIC18F87J50 FAMILY

TABLE 11-3: REGISTERS ASSOCIATED WITH PMP MODULE

Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Reset

Values

on Page:

INTCON GIE/GIEH PEIE/GIEL TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 61

PIR1 PMPIF ADIF RC1IF TX1IF SSP1IF CCP1IF TMR2IF TMR1IF 64

PIE1 PMPIE ADIE RC1IE TX1IE SSP1IE CCP1IE TMR2IE TMR1IE 64

IPR1 PMPIP ADIP RC1IP TX1IP SSP1IP CCP1IP TMR2IP TMR1IP 64

PMCONH PMPEN — PSIDL ADRMUX1 ADRMUX0 PTBEEN PTWREN PTRDEN 66

PMCONL CSF1 CSF0 ALP CS2P CS1P BEP WRSP RDSP 67

PMADDRH(1)/ CS2 CS1 Parallel Master Port Address, High Byte 66

PMDOUT1H(1) Parallel Port Out Data, High Byte (Buffer 1) 66

PMADDRL(1)/ Parallel Master Port Address, Low Byte 66

PMDOUT1L(1) Parallel Port Out Data, Low Byte (Buffer 0) 66

PMDOUT2H Parallel Port Out Data, High Byte (Buffer 3) 66

PMDOUT2L Parallel Port Out Data, Low Byte (Buffer 2) 66

PMDIN1H Parallel Port In Data, High Byte (Buffer 1) 66

PMDIN1L Parallel Port In Data, Low Byte (Buffer 0) 66

PMDIN2H Parallel Port In Data, High Byte (Buffer 3) 67

PMDIN2L Parallel Port In Data, Low Byte (Buffer 2) 67

PMMODEH BUSY IRQM1 IRQM0 INCM1 INCM0 MODE16 MODE1 MODE0 67

PMMODEL WAITB1 WAITB0 WAITM3 WAITM2 WAITM1 WAITM0 WAITE1 WAITE0 67

PMEH PTEN15 PTEN14 PTEN13 PTEN12 PTEN11 PTEN10 PTEN9 PTEN8 67

PMEL PTEN7 PTEN6 PTEN5 PTEN4 PTEN3 PTEN2 PTEN1 PTEN0 67

PMSTATH IBF IBOV —— IB3F IB2F IB1F IB0F 67

PMSTATL OBE OBUF —— OB3E OB2E OB1E OB0E 67

PADCFG1(2) — — — — — — — PMPTTL 62

Legend: — = unimplemented, read as ‘0’. Shaded cells are not used during ECCP operation.

Note 1: The PMADDRH/PMDOUT1H and PMADDRL/PMDOUT1L register pairs share the physical registers and

addresses, but have different functions determined by the module’s operating mode.

2: Configuration SFR, overlaps with default SFR at this address; available only when WDTCON<4> = 1.

PIC18F87J50 FAMILY

12.0 TIMER0 MODULE

The Timer0 module incorporates the following features:

• Software selectable operation as a timer or

counter in both 8-bit or 16-bit modes

• Readable and writable registers

• Dedicated 8-bit, software programmable

prescaler

• Selectable clock source (internal or external)

• Edge select for external clock

• Interrupt-on-overflow

The T0CON register (Register 12-1) controls all

aspects of the module’s operation, including the

prescale selection. It is both readable and writable.

A simplified block diagram of the Timer0 module in 8-bit

mode is shown in Figure 12-1. Figure 12-2 shows a

simplified block diagram of the Timer0 module in 16-bit

mode.

R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1

TMR0ON T08BIT T0CS T0SE PSA T0PS2 T0PS1 T0PS0

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 TMR0ON: Timer0 On/Off Control bit

1 = Enables Timer0

0 = Stops Timer0

bit 6 T08BIT: Timer0 8-Bit/16-Bit Control bit

1 = Timer0 is configured as an 8-bit timer/counter

0 = Timer0 is configured as a 16-bit timer/counter

bit 5 T0CS: Timer0 Clock Source Select bit

1 = Transition on T0CKI pin

0 = Internal instruction cycle clock (CLKO)

bit 4 T0SE: Timer0 Source Edge Select bit

1 = Increment on high-to-low transition on T0CKI pin

0 = Increment on low-to-high transition on T0CKI pin

bit 3 PSA: Timer0 Prescaler Assignment bit

1 = TImer0 prescaler is not assigned. Timer0 clock input bypasses prescaler.

0 = Timer0 prescaler is assigned. Timer0 clock input comes from prescaler output.

bit 2-0 T0PS2:T0PS0: Timer0 Prescaler Select bits

111 = 1:256 Prescale value

110 = 1:128 Prescale value

101 = 1:64 Prescale value

100 = 1:32 Prescale value

011 = 1:16 Prescale value

010 = 1:8 Prescale value

001 = 1:4 Prescale value

000 = 1:2 Prescale value

PIC18F87J50 FAMILY

12.1 Timer0 Operation

Timer0 can operate as either a timer or a counter. The

mode is selected with the T0CS bit (T0CON<5>). In

Timer mode (T0CS = 0), the module increments on

every clock by default unless a different prescaler value

is selected (see Section 12.3 “Prescaler”). If the

TMR0 register is written to, the increment is inhibited

for the following two instruction cycles. The user can

work around this by writing an adjusted value to the

TMR0 register.

The Counter mode is selected by setting the T0CS bit

(= 1). In this mode, Timer0 increments either on every

rising or falling edge of pin RA4/T0CKI. The increment-

ing edge is determined by the Timer0 Source Edge

Select bit, T0SE (T0CON<4>); clearing this bit selects

the rising edge. Restrictions on the external clock input

are discussed below.

An external clock source can be used to drive Timer0;

however, it must meet certain requirements to ensure

that the external clock can be synchronized with the

internal phase clock (T

OSC). There is a delay between

synchronization and the onset of incrementing the

timer/counter.

12.2 Timer0 Reads and Writes in

16-Bit Mode

TMR0H is not the actual high byte of Timer0 in 16-bit

mode. It is actually a buffered version of the real high

byte of Timer0 which is not directly readable nor writ-

able (refer to Figure 12-2). TMR0H is updated with the

contents of the high byte of Timer0 during a read of

TMR0L. This provides the ability to read all 16 bits of

Timer0 without having to verify that the read of the high

and low byte were valid, due to a rollover between

successive reads of the high and low byte.

Similarly, a write to the high byte of Timer0 must also

take place through the TMR0H Buffer register. The high

byte is updated with the contents of TMR0H when a

write occurs to TMR0L. This allows all 16 bits of Timer0

to be updated at once.

FIGURE 12-1: TIMER0 BLOCK DIAGRAM (8-BIT MODE)

FIGURE 12-2: TIMER0 BLOCK DIAGRAM (16-BIT MODE)

Note: Upon Reset, Timer0 is enabled in 8-bit mode with clock input from T0CKI max. prescale.

T0CKI pin

T0SE

T0CS

FOSC/4

Programmable

Prescaler

Sync with

Internal

Clocks

TMR0L

(2 TCY Delay)

Internal Data Bus

PSA

T0PS2:T0PS0

Set

TMR0IF

on Overflow

Note: Upon Reset, Timer0 is enabled in 8-bit mode with clock input from T0CKI max. prescale.

T0CKI pin

T0SE

T0CS

FOSC/4

Sync with

Internal

Clocks

TMR0L

(2 TCY Delay)

Internal Data Bus

PSA

T0PS2:T0PS0

Set

TMR0IF

on Overflow

TMR0

TMR0H

High Byte

Read TMR0L

Write TMR0L

Programmable

Prescaler

PIC18F87J50 FAMILY

12.3 Prescaler

An 8-bit counter is available as a prescaler for the Timer0

module. The prescaler is not directly readable or writable.

Its value is set by the PSA and T0PS2:T0PS0 bits

(T0CON<3:0>) which determine the prescaler

assignment and prescale ratio.

Clearing the PSA bit assigns the prescaler to the

Timer0 module. When it is assigned, prescale values

from 1:2 through 1:256 in power-of-2 increments are

selectable.

When assigned to the Timer0 module, all instructions

writing to the TMR0 register (e.g., CLRF TMR0, MOVWF

TMR0, BSF TMR0, etc.) clear the prescaler count.

12.3.1 SWITCHING PRESCALER

ASSIGNMENT

The prescaler assignment is fully under software

control and can be changed “on-the-fly” during program

execution.

12.4 Timer0 Interrupt

The TMR0 interrupt is generated when the TMR0

from FFFFh to 0000h in 16-bit mode. This overflow sets

the TMR0IF flag bit. The interrupt can be masked by

clearing the TMR0IE bit (INTCON<5>). Before

re-enabling the interrupt, the TMR0IF bit must be

cleared in software by the Interrupt Service Routine.

Since Timer0 is shut down in Sleep mode, the TMR0

interrupt cannot awaken the processor from Sleep.

TABLE 12-1: REGISTERS ASSOCIATED WITH TIMER0

Note: Writing to TMR0 when the prescaler is

assigned to Timer0 will clear the prescaler

count but will not change the prescaler

assignment.

Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Reset

Values

on Page:

TMR0L Timer0 Register Low Byte 62

TMR0H Timer0 Register High Byte 62

INTCON GIE/GIEH PEIE/GIEL TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 61

T0CON TMR0ON T08BIT T0CS T0SE PSA T0PS2 T0PS1 T0PS0 62

TRISA — — TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 64

Legend: — = unimplemented, read as ‘0’. Shaded cells are not used by Timer0.

PIC18F87J50 FAMILY

NOTES:

PIC18F87J50 FAMILY

13.0 TIMER1 MODULE

The Timer1 timer/counter module incorporates these

features:

• Software selectable operation as a 16-bit timer or

counter

• Readable and writable 8-bit registers (TMR1H

and TMR1L)

• Selectable clock source (internal or external) with

device clock or Timer1 oscillator internal options

• Interrupt on overflow

• Reset on CCP Special Event Trigger

• Device clock status flag (T1RUN)

A simplified block diagram of the Timer1 module is

shown in Figure 13-1. A block diagram of the module’s

operation in Read/Write mode is shown in Figure 13-2.

The module incorporates its own low-power oscillator

to provide an additional clocking option. The Timer1

oscillator can also be used as a low-power clock source

for the microcontroller in power-managed operation.

Timer1 can also be used to provide Real-Time Clock

(RTC) functionality to applications with only a minimal

addition of external components and code overhead.

Timer1 is controlled through the T1CON Control

Oscillator Enable bit (T1OSCEN). Timer1 can be

enabled or disabled by setting or clearing control bit,

TMR1ON (T1CON<0>).

R/W-0 R-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

RD16 T1RUN T1CKPS1 T1CKPS0

T1OSCEN

T1SYNC TMR1CS TMR1ON

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 RD16: 16-Bit Read/Write Mode Enable bit

1 = Enables register read/write of TImer1 in one 16-bit operation

0 = Enables register read/write of Timer1 in two 8-bit operations

bit 6 T1RUN: Timer1 System Clock Status bit

1 = Device clock is derived from Timer1 oscillator

0 = Device clock is derived from another source

bit 5-4 T1CKPS1:T1CKPS0: Timer1 Input Clock Prescale Select bits

11 = 1:8 Prescale value

10 = 1:4 Prescale value

01 = 1:2 Prescale value

00 = 1:1 Prescale value

bit 3 T1OSCEN: Timer1 Oscillator Enable bit

1 = Timer1 oscillator is enabled

0 = Timer1 oscillator is shut off

The oscillator inverter and feedback resistor are turned off to eliminate power drain.

bit 2 T1SYNC: Timer1 External Clock Input Synchronization Select bit

When TMR1CS = 1:

1 = Do not synchronize external clock input

0 = Synchronize external clock input

When TMR1CS = 0:

This bit is ignored. Timer1 uses the internal clock when TMR1CS = 0.

bit 1 TMR1CS: Timer1 Clock Source Select bit

1 = External clock from pin RC0/T1OSO/T13CKI (on the rising edge)

0 = Internal clock (FOSC/4)

bit 0 TMR1ON: Timer1 On bit

1 = Enables Timer1

0 =Stops Timer1

Note 1: Default (legacy) SFR at this address, available when WDTCON<4> = 0.

PIC18F87J50 FAMILY

13.1 Timer1 Operation

Timer1 can operate in one of these modes:

•Timer

• Synchronous Counter

• Asynchronous Counter

The operating mode is determined by the clock select

bit, TMR1CS (T1CON<1>). When TMR1CS is cleared

(= 0), Timer1 increments on every internal instruction

cycle (FOSC/4). When the bit is set, Timer1 increments

on every rising edge of the Timer1 external clock input

or the Timer1 oscillator, if enabled.

When Timer1 is enabled, the RC1/T1OSI and

RC0/T1OSO/T13CKI pins become inputs. This means

the values of TRISC<1:0> are ignored and the pins are

read as ‘0’.

FIGURE 13-1: TIMER1 BLOCK DIAGRAM

FIGURE 13-2: TIMER1 BLOCK DIAGRAM (16-BIT READ/WRITE MODE)

T1SYNC

TMR1CS

T1CKPS1:T1CKPS0

Sleep Input

T1OSCEN(1)

FOSC/4

Internal

Clock

On/Off

Prescaler

1, 2, 4, 8

Synchronize

Detect

T1OSO/T13CKI

T1OSI

TMR1ON

TMR1L

Set

TMR1IF

on Overflow

TMR1

High Byte

Clear TMR1

(ECCPx Special Event Trigger)

Timer1 Oscillator

Note 1: When enable bit, T1OSCEN, is cleared, the inverter and feedback resistor are turned off to eliminate power drain.

On/Off

Timer1

Timer1 Clock Input

T1SYNC

TMR1CS

T1CKPS1:T1CKPS0

Sleep Input

T1OSCEN(1)

FOSC/4

Internal

Clock

Prescaler

1, 2, 4, 8

Synchronize

Detect

T1OSO/T13CKI

T1OSI

Note 1: When enable bit, T1OSCEN, is cleared, the inverter and feedback resistor are turned off to eliminate power drain.

TMR1L

Internal Data Bus

Set

TMR1IF

on Overflow

TMR1

TMR1H

High Byte

Read TMR1L

Write TMR1L

TMR1ON

Clear TMR1

(ECCPx Special Event Trigger)

Timer1 Oscillator

On/Off

Timer1

Timer1 Clock Input

PIC18F87J50 FAMILY

13.2 Timer1 16-Bit Read/Write Mode

Timer1 can be configured for 16-bit reads and writes

(see Figure 13-2). When the RD16 control bit,

T1CON<7>, is set, the address for TMR1H is mapped

to a buffer register for the high byte of Timer1. A read

from TMR1L will load the contents of the high byte of

Timer1 into the Timer1 High Byte Buffer register. This

provides the user with the ability to accurately read all

16 bits of Timer1 without having to determine whether

a read of the high byte, followed by a read of the low

byte, has become invalid due to a rollover between

reads.

A write to the high byte of Timer1 must also take place

through the TMR1H Buffer register. The Timer1 high

byte is updated with the contents of TMR1H when a

write occurs to TMR1L. This allows a user to write all

16 bits to both the high and low bytes of Timer1 at once.

The high byte of Timer1 is not directly readable or

writable in this mode. All reads and writes must take

place through the Timer1 High Byte Buffer register.

Writes to TMR1H do not clear the Timer1 prescaler.

The prescaler is only cleared on writes to TMR1L.

13.3 Timer1 Oscillator

An on-chip crystal oscillator circuit is incorporated

between pins T1OSI (input) and T1OSO (amplifier

output). It is enabled by setting the Timer1 Oscillator

Enable bit, T1OSCEN (T1CON<3>). The oscillator is a

low-power circuit rated for 32 kHz crystals. It will

continue to run during all power-managed modes. The

circuit for a typical LP oscillator is shown in Figure 13-3.

Table 13-1 shows the capacitor selection for the Timer1

oscillator.

The user must provide a software time delay to ensure

proper start-up of the Timer1 oscillator.

FIGURE 13-3: EXTERNAL

COMPONENTS FOR THE

TIMER1 LP OSCILLATOR

TABLE 13-1: CAPACITOR SELECTION FOR

THE TIMER OSCILLATOR(2,3,4)

13.3.1 USING TIMER1 AS A

CLOCK SOURCE

The Timer1 oscillator is also available as a clock source

in power-managed modes. By setting the clock select

bits, SCS1:SCS0 (OSCCON<1:0>), to ‘01’, the device

switches to SEC_RUN mode; both the CPU and

peripherals are clocked from the Timer1 oscillator. If the

IDLEN bit (OSCCON<7>) is cleared and a SLEEP

instruction is executed, the device enters SEC_IDLE

mode. Additional details are available in Section 3.0

“Power-Managed Modes”.

Whenever the Timer1 oscillator is providing the clock

source, the Timer1 system clock status flag, T1RUN

(T1CON<6>), is set. This can be used to determine the

controller’s current clocking mode. It can also indicate

the clock source being currently used by the Fail-Safe

Clock Monitor. If the Clock Monitor is enabled and the

Timer1 oscillator fails while providing the clock, polling

the T1RUN bit will indicate whether the clock is being

provided by the Timer1 oscillator or another source.

13.3.2 TIMER1 OSCILLATOR LAYOUT

CONSIDERATIONS

The Timer1 oscillator circuit draws very little power

during operation. Due to the low-power nature of the

oscillator, it may also be sensitive to rapidly changing

signals in close proximity.

The oscillator circuit, shown in Figure 13-3, should be

located as close as possible to the microcontroller.

There should be no circuits passing within the oscillator

circuit boundaries other than VSS or VDD.

Note: See the Notes with Table 13-1 for additional

information about capacitor selection.

XTAL

PIC18F87J50

T1OSI

T1OSO

32.768 kHz

27 pF

Oscillator

Type Freq. C1 C2

LP 32 kHz 27 pF(1) 27 pF(1)

Note 1: Microchip suggests these values as a

starting point in validating the oscillator

circuit.

2: Higher capacitance increases the stability

of the oscillator but also increases the

start-up time.

3: Since each resonator/crystal has its own

characteristics, the user should consult

the resonator/crystal manufacturer for

appropriate values of external

components.

4: Capacitor values are for design guidance

only.

PIC18F87J50 FAMILY

If a high-speed circuit must be located near the oscilla-

tor (such as the ECCP1 pin in Output Compare or PWM

mode, or the primary oscillator using the OSC2 pin), a

grounded guard ring around the oscillator circuit, as

shown in Figure 13-4, may be helpful when used on a

single-sided PCB or in addition to a ground plane.

FIGURE 13-4: OSCILLATOR CIRCUIT

WITH GROUNDED

GUARD RING

13.4 Timer1 Interrupt

The TMR1 register pair (TMR1H:TMR1L) increments

from 0000h to FFFFh and rolls over to 0000h. The

Timer1 interrupt, if enabled, is generated on overflow

which is latched in interrupt flag bit, TMR1IF

(PIR1<0>). This interrupt can be enabled or disabled

by setting or clearing the Timer1 Interrupt Enable bit,

TMR1IE (PIE1<0>).

13.5 Resetting Timer1 Using the ECCP

Special Event Trigger

If ECCP1 or ECCP2 is configured to use Timer1 and to

generate a Special Event Trigger in Compare mode

(CCPxM3:CCPxM0 = 1011), this signal will reset

Timer3. The trigger from ECCP2 will also start an A/D

conversion if the A/D module is enabled (see

Section 18.2.1 “Special Event Trigger” for more

information).

The module must be configured as either a timer or a

synchronous counter to take advantage of this feature.

When used this way, the CCPRxH:CCPRxL register

pair effectively becomes a period register for Timer1.

If Timer1 is running in Asynchronous Counter mode,

this Reset operation may not work.

In the event that a write to Timer1 coincides with a

Special Event Trigger, the write operation will take

precedence.

13.6 Using Timer1 as a Real-Time Clock

Adding an external LP oscillator to Timer1 (such as the

one described in Section 13.3 “Timer1 Oscillator”)

gives users the option to include RTC functionality to

their applications. This is accomplished with an inex-

pensive watch crystal to provide an accurate time base

and several lines of application code to calculate the

time. When operating in Sleep mode and using a

battery or supercapacitor as a power source, it can

completely eliminate the need for a separate RTC

device and battery backup.

The application code routine, RTCisr, shown in

Example 13-1, demonstrates a simple method to

increment a counter at one-second intervals using an

Interrupt Service Routine. Incrementing the TMR1

the routine which increments the seconds counter by

one. Additional counters for minutes and hours are

incremented as the previous counter overflows.

Since the register pair is 16 bits wide, counting up to

overflow the register directly from a 32.768 kHz clock

would take 2 seconds. To force the overflow at the

required one-second intervals, it is necessary to pre-

load it. The simplest method is to set the MSb of

TMR1H with a BSF instruction. Note that the TMR1L

introduce cumulative error over many cycles.

For this method to be accurate, Timer1 must operate in

Asynchronous mode and the Timer1 overflow interrupt

must be enabled (PIE1<0> = 1) as shown in the

routine, RTCinit. The Timer1 oscillator must also be

enabled and running at all times.

13.7 Considerations in Asynchronous

Counter Mode

Following a Timer1 interrupt and an update to the

TMR1 registers, the Timer1 module uses a falling edge

on its clock source to trigger the next register update on

the rising edge. If the update is completed after the

clock input has fallen, the next rising edge will not be

counted.

If the application can reliably update TMR1 before the

timer input goes low, no additional action is needed.

Otherwise, an adjusted update can be performed

following a later Timer1 increment. This can be done by

monitoring TMR1L within the interrupt routine until it

increments, and then updating the TMR1H:TMR1L reg-

ister pair while the clock is low, or one-half of the period

of the clock source. Assuming that Timer1 is being

used as a Real-Time Clock, the clock source is a

32.768 kHz crystal oscillator. In this case, one-half

period of the clock is 15.25 μs.

VDD

OSC1

VSS

OSC2

RC0

RC1

RC2

Note: Not drawn to scale.

Note: The Special Event Triggers from the

ECCPx module will not set the TMR1IF

interrupt flag bit (PIR1<0>).

PIC18F87J50 FAMILY

The Real-Time Clock application code in Example 13-1

shows a typical ISR for Timer1, as well as the optional

code required if the update cannot be done reliably

within the required interval.

EXAMPLE 13-1: IMPLEMENTING A REAL-TIME CLOCK USING A TIMER1 INTERRUPT SERVICE

RTCinit

MOVLW 80h ; Preload TMR1 register pair

MOVWF TMR1H ; for 1 second overflow

CLRF TMR1L

MOVLW b’00001111’ ; Configure for external clock,

MOVWF T1CON ; Asynchronous operation, external oscillator

CLRF secs ; Initialize timekeeping registers

CLRF mins ;

MOVLW .12

MOVWF hours

BSF PIE1, TMR1IE ; Enable Timer1 interrupt

RETURN

RTCisr

; Insert the next 4 lines of code when TMR1

; can not be reliably updated before clock pulse goes low

BTFSC TMR1L,0 ; wait for TMR1L to become clear

BRA $-2 ; (may already be clear)

BTFSS TMR1L,0 ; wait for TMR1L to become set

BRA $-2 ; TMR1 has just incremented

; If TMR1 update can be completed before clock pulse goes low

; Start ISR here

BSF TMR1H, 7 ; Preload for 1 sec overflow

BCF PIR1, TMR1IF ; Clear interrupt flag

INCF secs, F ; Increment seconds

MOVLW .59 ; 60 seconds elapsed?

CPFSGT secs

RETURN ; No, done

CLRF secs ; Clear seconds

INCF mins, F ; Increment minutes

MOVLW .59 ; 60 minutes elapsed?

CPFSGT mins

RETURN ; No, done

CLRF mins ; clear minutes

INCF hours, F ; Increment hours

MOVLW .23 ; 24 hours elapsed?

CPFSGT hours

RETURN ; No, done

CLRF hours ; Reset hours

RETURN ; Done

PIC18F87J50 FAMILY

TABLE 13-2: REGISTERS ASSOCIATED WITH TIMER1 AS A TIMER/COUNTER

Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Reset

Values

on Page:

INTCON GIE/GIEH PEIE/GIEL TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 61

PIR1 PMPIF ADIF RC1IF TX1IF SSP1IF CCP1IF TMR2IF TMR1IF 64

PIE1 PMPIE ADIE RC1IE TX1IE SSP1IE CCP1IE TMR2IE TMR1IE 64

IPR1 PMPIP ADIP RC1IP TX1IP SSP1IP CCP1IP TMR2IP TMR1IP 64

TMR1L(1) Timer1 Register Low Byte 62

TMR1H(1) Timer1 Register High Byte 62

T1CON(1) RD16 T1RUN T1CKPS1 T1CKPS0 T1OSCEN T1SYNC TMR1CS TMR1ON 62

Legend: Shaded cells are not used by the Timer1 module.

Note 1: Default (legacy) SFR at this address, available when WDTCON<4> = 0.

PIC18F87J50 FAMILY

14.0 TIMER2 MODULE

The Timer2 module incorporates the following features:

• 8-Bit Timer and Period registers (TMR2 and PR2,

respectively)

• Readable and writable (both registers)

• Software programmable prescaler

(1:1, 1:4 and 1:16)

• Software programmable postscaler

(1:1 through 1:16)

• Interrupt on TMR2 to PR2 match

• Optional use as the shift clock for the

MSSP modules

The module is controlled through the T2CON register

(Register 14-1) which enables or disables the timer and

configures the prescaler and postscaler. Timer2 can be

shut off by clearing control bit, TMR2ON (T2CON<2>),

to minimize power consumption.

A simplified block diagram of the module is shown in

Figure 14-1.

14.1 Timer2 Operation

In normal operation, TMR2 is incremented from 00h on

each clock (FOSC/4). A 4-bit counter/prescaler on the

clock input gives direct input, divide-by-4 and

divide-by-16 prescale options. These are selected by

the prescaler control bits, T2CKPS1:T2CKPS0

(T2CON<1:0>). The value of TMR2 is compared to that

of the Period register, PR2, on each clock cycle. When

the two values match, the comparator generates a

match signal as the timer output. This signal also resets

the value of TMR2 to 00h on the next cycle and drives

the output counter/postscaler (see Section 14.2

“Timer2 Interrupt”).

The TMR2 and PR2 registers are both directly readable

and writable. The TMR2 register is cleared on any

device Reset, while the PR2 register initializes at FFh.

Both the prescaler and postscaler counters are cleared

on the following events:

• a write to the TMR2 register

• a write to the T2CON register

• any device Reset (Power-on Reset, MCLR Reset,

Watchdog Timer Reset or Brown-out Reset)

TMR2 is not cleared when T2CON is written.

U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

— T2OUTPS3 T2OUTPS2 T2OUTPS1 T2OUTPS0 TMR2ON T2CKPS1 T2CKPS0

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 Unimplemented: Read as ‘0’

bit 6-3 T2OUTPS3:T2OUTPS0: Timer2 Output Postscale Select bits

0000 = 1:1 Postscale

0001 = 1:2 Postscale

•

1111 = 1:16 Postscale

bit 2 TMR2ON: Timer2 On bit

1 = Timer2 is on

0 = Timer2 is off

bit 1-0 T2CKPS1:T2CKPS0: Timer2 Clock Prescale Select bits

00 = Prescaler is 1

01 = Prescaler is 4

1x = Prescaler is 16

PIC18F87J50 FAMILY

14.2 Timer2 Interrupt

Timer2 can also generate an optional device interrupt.

The Timer2 output signal (TMR2 to PR2 match) pro-

vides the input for the 4-bit output counter/postscaler.

This counter generates the TMR2 match interrupt flag

which is latched in TMR2IF (PIR1<1>). The interrupt is

enabled by setting the TMR2 Match Interrupt Enable

bit, TMR2IE (PIE1<1>).

A range of 16 postscale options (from 1:1 through 1:16

inclusive) can be selected with the postscaler control

bits, T2OUTPS3:T2OUTPS0 (T2CON<6:3>).

14.3 Timer2 Output

The unscaled output of TMR2 is available primarily to

the ECCP modules, where it is used as a time base for

operations in PWM mode.

Timer2 can be optionally used as the shift clock source

for the MSSP modules operating in SPI mode.

Additional information is provided in Section 19.0

“Master Synchronous Serial Port (MSSP) Module”.

FIGURE 14-1: TIMER2 BLOCK DIAGRAM

TABLE 14-1: REGISTERS ASSOCIATED WITH TIMER2 AS A TIMER/COUNTER

Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Reset

Values

on Page:

INTCON GIE/GIEH PEIE/GIEL TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 61

PIR1 PMPIF ADIF RC1IF TX1IF SSP1IF CCP1IF TMR2IF TMR1IF 64

PIE1 PMPIE ADIE RC1IE TX1IE SSP1IE CCP1IE TMR2IE TMR1IE 64

IPR1 PMPIP ADIP RC1IP TX1IP SSP1IP CCP1IP TMR2IP TMR1IP 64

TMR2(1) Timer2 Register 62

T2CON — T2OUTPS3 T2OUTPS2 T2OUTPS1 T2OUTPS0 TMR2ON T2CKPS1 T2CKPS0 62

PR2(1) Timer2 Period Register 62

Legend: — = unimplemented, read as ‘0’. Shaded cells are not used by the Timer2 module.

Note 1: Default (legacy) SFR at this address, available when WDTCON<4> = 0.

Comparator

TMR2 Output

TMR2

Postscaler

Prescaler PR2

FOSC/4

1:1 to 1:16

1:1, 1:4, 1:16

T2OUTPS3:T2OUTPS0

T2CKPS1:T2CKPS0

Set TMR2IF

Internal Data Bus

Reset

TMR2/PR2

(to PWM or MSSPx)

Match

PIC18F87J50 FAMILY

15.0 TIMER3 MODULE

The Timer3 timer/counter module incorporates these

features:

• Software selectable operation as a 16-bit timer or

counter

• Readable and writable 8-bit registers (TMR3H

and TMR3L)

• Selectable clock source (internal or external) with

device clock or Timer1 oscillator internal options

• Interrupt-on-overflow

• Module Reset on ECCP Special Event Trigger

A simplified block diagram of the Timer3 module is

shown in Figure 15-1. A block diagram of the module’s

operation in Read/Write mode is shown in Figure 15-2.

The Timer3 module is controlled through the T3CON

options for the CCP and ECCP modules; see

Section 17.1.1 “CCP Modules and Timer

Resources” for more information.

R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

RD16 T3CCP2 T3CKPS1 T3CKPS0 T3CCP1 T3SYNC TMR3CS TMR3ON

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 RD16: 16-Bit Read/Write Mode Enable bit

1 = Enables register read/write of Timer3 in one 16-bit operation

0 = Enables register read/write of Timer3 in two 8-bit operations

bit 6,3 T3CCP2:T3CCP1: Timer3 and Timer1 to ECCPx/CCPx Enable bits

11 = Timer3 and Timer4 are the clock sources for all ECCP/CCP modules

10 = Timer3 and Timer4 are the clock sources for ECCP3, CCP4 and CCP5;

Timer1 and Timer2 are the clock sources for ECCP1 and ECCP2

01 = Timer3 and Timer4 are the clock sources for ECCP2, ECCP3, CCP4 and CCP5;

Timer1 and Timer2 are the clock sources for ECCP1

00 = Timer1 and Timer2 are the clock sources for all ECCP/CCP modules

bit 5-4 T3CKPS1:T3CKPS0: Timer3 Input Clock Prescale Select bits

11 = 1:8 Prescale value

10 = 1:4 Prescale value

01 = 1:2 Prescale value

00 = 1:1 Prescale value

bit 2 T3SYNC: Timer3 External Clock Input Synchronization Control bit

(Not usable if the device clock comes from Timer1/Timer3.)

When TMR3CS = 1:

1 = Do not synchronize external clock input

0 = Synchronize external clock input

When TMR3CS = 0:

This bit is ignored. Timer3 uses the internal clock when TMR3CS = 0.

bit 1 TMR3CS: Timer3 Clock Source Select bit

1 = External clock input from Timer1 oscillator or T13CKI (on the rising edge after the first

falling edge)

0 = Internal clock (FOSC/4)

bit 0 TMR3ON: Timer3 On bit

1 = Enables Timer3

0 = Stops Timer3

PIC18F87J50 FAMILY

15.1 Timer3 Operation

Timer3 can operate in one of three modes:

•Timer

• Synchronous Counter

• Asynchronous Counter

The operating mode is determined by the clock select

bit, TMR3CS (T3CON<1>). When TMR3CS is cleared

(= 0), Timer3 increments on every internal instruction

cycle (FOSC/4). When the bit is set, Timer3 increments

on every rising edge of the Timer1 external clock input

or the Timer1 oscillator, if enabled.

As with Timer1, the RC1/T1OSI and

RC0/T1OSO/T13CKI pins become inputs when the

Timer1 oscillator is enabled. This means the values of

TRISC<1:0> are ignored and the pins are read as ‘0’.

FIGURE 15-1: TIMER3 BLOCK DIAGRAM

FIGURE 15-2: TIMER3 BLOCK DIAGRAM (16-BIT READ/WRITE MODE)

T3SYNC

TMR3CS

T3CKPS1:T3CKPS0

Sleep Input

T1OSCEN(1)

FOSC/4

Internal

Clock

Prescaler

1, 2, 4, 8

Synchronize

Detect

T1OSO/T13CKI

T1OSI

TMR3ON

TMR3L Set

TMR3IF

on Overflow

TMR3

High Byte

Timer1 Oscillator

Note 1: When enable bit, T1OSCEN, is cleared, the inverter and feedback resistor are turned off to eliminate power drain.

On/Off

Timer3

ECCPx Special Event Trigger

ECCPx Select from T3CON<6,3>

Clear TMR3

Timer1 Clock Input

T3SYNC

TMR3CS

T3CKPS1:T3CKPS0

Sleep Input

T1OSCEN(1)

FOSC/4

Internal

Clock

Prescaler

1, 2, 4, 8

Synchronize

Detect

T13CKI/T1OSO

T1OSI

Note 1: When enable bit, T1OSCEN, is cleared, the inverter and feedback resistor are turned off to eliminate power drain.

TMR3L

Internal Data Bus

Set

TMR3IF

on Overflow

TMR3

TMR3H

High Byte

Read TMR1L

Write TMR1L

TMR3ON

ECCPx Special Event Trigger

Timer1 Oscillator

On/Off

Timer3

Timer1 Clock Input

ECCPx Select from T3CON<6,3>

Clear TMR3

PIC18F87J50 FAMILY

15.2 Timer3 16-Bit Read/Write Mode

Timer3 can be configured for 16-bit reads and writes

(see Figure 15-2). When the RD16 control bit

(T3CON<7>) is set, the address for TMR3H is mapped

to a buffer register for the high byte of Timer3. A read

from TMR3L will load the contents of the high byte of

Timer3 into the Timer3 High Byte Buffer register. This

provides the user with the ability to accurately read all

16 bits of Timer1 without having to determine whether

a read of the high byte, followed by a read of the low

byte, has become invalid due to a rollover between

reads.

A write to the high byte of Timer3 must also take place

through the TMR3H Buffer register. The Timer3 high

byte is updated with the contents of TMR3H when a

write occurs to TMR3L. This allows a user to write all

16 bits to both the high and low bytes of Timer3 at once.

The high byte of Timer3 is not directly readable or

writable in this mode. All reads and writes must take

place through the Timer3 High Byte Buffer register.

Writes to TMR3H do not clear the Timer3 prescaler.

The prescaler is only cleared on writes to TMR3L.

15.3 Using the Timer1 Oscillator as the

Timer3 Clock Source

The Timer1 internal oscillator may be used as the clock

source for Timer3. The Timer1 oscillator is enabled by

setting the T1OSCEN (T1CON<3>) bit. To use it as the

Timer3 clock source, the TMR3CS bit must also be set.

As previously noted, this also configures Timer3 to

increment on every rising edge of the oscillator source.

The Timer1 oscillator is described in Section 13.0

“Timer1 Module”.

15.4 Timer3 Interrupt

The TMR3 register pair (TMR3H:TMR3L) increments

from 0000h to FFFFh and overflows to 0000h. The

Timer3 interrupt, if enabled, is generated on overflow

and is latched in interrupt flag bit, TMR3IF (PIR2<1>).

This interrupt can be enabled or disabled by setting or

clearing the Timer3 Interrupt Enable bit, TMR3IE

(PIE2<1>).

15.5 Resetting Timer3 Using the ECCP

Special Event Trigger

If ECCP1 or ECCP2 is configured to use Timer3 and to

generate a Special Event Trigger in Compare mode

(CCPxM3:CCPxM0 = 1011), this signal will reset

Timer3. The trigger from ECCP2 will also start an A/D

conversion if the A/D module is enabled (see

Section 18.2.1 “Special Event Trigger” for more

information).

The module must be configured as either a timer or

synchronous counter to take advantage of this feature.

When used this way, the CCPRxH:CCPRxL register

pair effectively becomes a period register for Timer3.

If Timer3 is running in Asynchronous Counter mode,

the Reset operation may not work.

In the event that a write to Timer3 coincides with a

Special Event Trigger from an ECCP module, the write

will take precedence.

TABLE 15-1: REGISTERS ASSOCIATED WITH TIMER3 AS A TIMER/COUNTER

Note: The Special Event Triggers from the

ECCPx module will not set the TMR3IF

interrupt flag bit (PIR1<0>).

Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Reset

Values

on Page:

INTCON GIE/GIEH PEIE/GIEL TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 61

PIR2 OSCFIF CM2IF CM1IF USBIF BCL1IF LVDIF TMR3IF CCP2IF 64

PIE2 OSCFIE CM2IE CM1IE USBIE BCL1IE LVDIE TMR3IE CCP2IE 64

IPR2 OSCFIP CM2IP CM1IP USBIP BCL1IP LVDIP TMR3IP CCP2IP 64

TMR3L Timer3 Register Low Byte 65

TMR3H Timer3 Register High Byte 65

T1CON(1) RD16 T1RUN T1CKPS1 T1CKPS0 T1OSCEN T1SYNC TMR1CS TMR1ON 62

T3CON RD16 T3CCP2 T3CKPS1 T3CKPS0 T3CCP1 T3SYNC TMR3CS TMR3ON 65

Legend: — = unimplemented, read as ‘0’. Shaded cells are not used by the Timer3 module.

Note 1: Default (legacy) SFR at this address, available when WDTCON<4> = 0.

PIC18F87J50 FAMILY

NOTES:

PIC18F87J50 FAMILY

16.0 TIMER4 MODULE

The Timer4 timer module has the following features:

• 8-bit timer register (TMR4)

• 8-bit period register (PR4)

• Readable and writable (both registers)

• Software programmable prescaler (1:1, 1:4, 1:16)

• Software programmable postscaler (1:1 to 1:16)

• Interrupt on TMR4 match of PR4

Timer4 has a control register shown in Register 16-1.

Timer4 can be shut off by clearing control bit, TMR4ON

(T4CON<2>), to minimize power consumption. The

prescaler and postscaler selection of Timer4 are also

controlled by this register. Figure 16-1 is a simplified

block diagram of the Timer4 module.

16.1 Timer4 Operation

Timer4 can be used as the PWM time base for the

PWM mode of the ECCP/CCP modules. The TMR4

device Reset. The input clock (FOSC/4) has a prescale

option of 1:1, 1:4 or 1:16, selected by control bits

T4CKPS1:T4CKPS0 (T4CON<1:0>). The match out-

put of TMR4 goes through a 4-bit postscaler (which

gives a 1:1 to 1:16 scaling inclusive) to generate a

TMR4 interrupt, latched in flag bit, TMR4IF (PIR3<3>).

The prescaler and postscaler counters are cleared

when any of the following occurs:

• a write to the TMR4 register

• a write to the T4CON register

• any device Reset (Power-on Reset, MCLR Reset,

Watchdog Timer Reset or Brown-out Reset)

TMR4 is not cleared when T4CON is written.

U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

— T4OUTPS3 T4OUTPS2 T4OUTPS1 T4OUTPS0 TMR4ON T4CKPS1 T4CKPS0

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 Unimplemented: Read as ‘0’

bit 6-3 T4OUTPS3:T4OUTPS0: Timer4 Output Postscale Select bits

0000 = 1:1 Postscale

0001 = 1:2 Postscale

•

1111 = 1:16 Postscale

bit 2 TMR4ON: Timer4 On bit

1 = Timer4 is on

0 = Timer4 is off

bit 1-0 T4CKPS1:T4CKPS0: Timer4 Clock Prescale Select bits

00 = Prescaler is 1

01 = Prescaler is 4

1x = Prescaler is 16

PIC18F87J50 FAMILY

16.2 Timer4 Interrupt

The Timer4 module has an 8-bit period register, PR4,

which is both readable and writable. Timer4 increments

from 00h until it matches PR4 and then resets to 00h on

the next increment cycle. The PR4 register is initialized

to FFh upon Reset.

16.3 Output of TMR4

The output of TMR4 (before the postscaler) is used

only as a PWM time base for the ECCP/CCP modules.

It is not used as a baud rate clock for the MSSP

modules as is the Timer2 output.

FIGURE 16-1: TIMER4 BLOCK DIAGRAM

TABLE 16-1: REGISTERS ASSOCIATED WITH TIMER4 AS A TIMER/COUNTER

Comparator

TMR4 Output

TMR4

Postscaler

Prescaler PR4

FOSC/4

1:1 to 1:16

1:1, 1:4, 1:16

T4OUTPS3:T4OUTPS0

T4CKPS1:T4CKPS0

Set TMR4IF

Internal Data Bus

Reset

TMR4/PR4

(to PWM)

Match

Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Reset

Values

on Page:

INTCON GIE/GIEH PEIE/GIEL TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 61

IPR3 SSP2IP BCL2IP RC2IP TX2IP TMR4IP CCP5IP CCP4IP CCP3IP 64

PIR3 SSP2IF BCL2IF RC2IF TX2IF TMR4IF CCP5IF CCP4IF CCP3IF 64

PIE3 SSP2IE BCL2IE RC2IE TX2IE TMR4IE CCP5IE CCP4IE CCP3IE 64

TMR4 Timer4 Register 65

T4CON — T4OUTPS3 T4OUTPS2 T4OUTPS1 T4OUTPS0 TMR4ON T4CKPS1 T4CKPS0 65

PR4(1) Timer4 Period Register 65

Legend: — = unimplemented, read as ‘0’. Shaded cells are not used by the Timer4 module.

Note 1: Default (legacy) SFR at this address, available when WDTCON<4> = 0.

PIC18F87J50 FAMILY

17.0 CAPTURE/COMPARE/PWM

(CCP) MODULES

Members of the PIC18F87J10 family of devices all have

a total of five CCP (Capture/Compare/PWM) modules.

Two of these (CCP4 and CCP5) implement standard

Capture, Compare and Pulse-Width Modulation (PWM)

modes and are discussed in this section. The other three

modules (ECCP1, ECCP2, ECCP3) implement

standard Capture and Compare modes, as well as

Enhanced PWM modes. These are discussed in

Section 18.0 “Enhanced Capture/Compare/PWM

(ECCP) Module”.

Each CCP/ECCP module contains a 16-bit register

which can operate as a 16-bit Capture register, a 16-bit

Compare register or a PWM Master/Slave Duty Cycle

tion in the following sections is described with respect

to CCP4, but is equally applicable to CCP5.

Capture and Compare operations described in this

chapter apply to all standard and Enhanced CCP

modules. The operations of PWM mode, described in

Section 17.4 “PWM Mode”, apply to CCP4 and CCP5

only.

Note: Throughout this section and Section 18.0

“Enhanced Capture/Compare/PWM (ECCP)

Module”, references to register and bit names

that may be associated with a specific CCP

module are referred to generically by the use of

‘x’ or ‘y’ in place of the specific module number.

Thus, “CCPxCON” might refer to the control

CCP5.

U-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

—— DCxB1 DCxB0 CCPxM3 CCPxM2 CCPxM1 CCPxM0

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7-6 Unimplemented: Read as ‘0’

bit 5-4 DCxB1:DCxB0: PWM Duty Cycle bit 1 and bit 0 for CCPx Module

Capture mode:

Unused.

Compare mode:

Unused.

PWM mode:

These bits are the two Least Significant bits (bit 1 and bit 0) of the 10-bit PWM duty cycle. The eight

Most Significant bits (DCx9:DCx2) of the duty cycle are found in CCPRxL.

bit 3-0 CCPxM3:CCPxM0: CCPx Module Mode Select bits

0000 = Capture/Compare/PWM disabled (resets CCPx module)

0001 = Reserved

0010 = Compare mode: toggle output on match (CCPxIF bit is set)

0011 = Reserved

0100 = Capture mode: every falling edge

0101 = Capture mode: every rising edge

0110 = Capture mode: every 4th rising edge

0111 = Capture mode: every 16th rising edge

1000 = Compare mode: initialize CCPx pin low; on compare match, force CCPx pin high

(CCPxIF bit is set)

1001 = Compare mode: initialize CCPx pin high; on compare match, force CCPx pin low

(CCPxIF bit is set)

1010 = Compare mode: generate software interrupt on compare match (CCPxIF bit is set,

CCPx pin reflects I/O state)

1011 = Compare mode: trigger special event, reset timer, start A/D conversion on

CCPx match (CCPxIF bit is set)

11xx =PWM mode

PIC18F87J50 FAMILY

17.1 CCP Module Configuration

Each Capture/Compare/PWM module is associated

with a control register (generically, CCPxCON) and a

data register (CCPRx). The data register, in turn, is

comprised of two 8-bit registers: CCPRxL (low byte)

and CCPRxH (high byte). All registers are both

readable and writable.

17.1.1 CCP MODULES AND TIMER

RESOURCES

The ECCP/CCP modules utilize Timers 1, 2, 3 or 4,

depending on the mode selected. Timer1 and Timer3

are available to modules in Capture or Compare

modes, while Timer2 and Timer4 are available for

modules in PWM mode.

TABLE 17-1: CCP MODE – TIMER

RESOURCE

The assignment of a particular timer to a module is

determined by the timer to CCP enable bits in the

T3CON register (Register 15-1, page 203). Depending

on the configuration selected, up to four timers may be

active at once, with modules in the same configuration

(Capture/Compare or PWM) sharing timer resources.

The possible configurations are shown in Figure 17-1.

17.1.2 OPEN-DRAIN OUTPUT OPTION

When operating in Output mode (i.e., in Compare or

PWM modes), the drivers for the CCPx pins can be

optionally configured as open-drain outputs. This fea-

ture allows the voltage level on the pin to be pulled to

a higher level through an external pull-up resistor, and

allows the output to communicate with external cir-

cuits without the need for additional level shifters. For

more information, see Section 10.1.4 “Open-Drain

Outputs”.

The open-drain output option is controlled by the bits in

the ODCON1 register. Setting the appropriate bit con-

figures the pin for the corresponding module for

open-drain operation. The ODCON1 memory shares

the same address space as TMR1H. The ODCON1

the WDTCON register(WDTCON<4>).

FIGURE 17-1: ECCP/CCP AND TIMER INTERCONNECT CONFIGURATIONS

CCP Mode Timer Resource

Capture

Compare

PWM

Timer1 or Timer3

Timer2 or Timer4

TMR1

CCP5

TMR2

TMR3

TMR4

CCP4

ECCP3

ECCP2

ECCP1

TMR1

TMR2

TMR3

CCP5

TMR4

CCP4

ECCP3

ECCP2

ECCP1

TMR1

TMR2

TMR3

CCP5

TMR4

CCP4

ECCP3

ECCP2

ECCP1

TMR1

TMR2

TMR3

CCP5

TMR4

CCP4

ECCP3

ECCP2

ECCP1

T3CCP<2:1> = 00 T3CCP<2:1> = 01 T3CCP<2:1> = 10 T3CCP<2:1> = 11

Timer1 is used for all Capture

and Compare operations for

all CCP modules. Timer2 is

used for PWM operations for

all CCP modules. Modules

may share either timer

resource as a common time

base.

Timer3 and Timer4 are not

available.

Timer1 and Timer2 are used

for Capture and Compare or

PWM operations for ECCP1

only (depending on selected

mode).

All other modules use either

Timer3 or Timer4. Modules

may share either timer

resource as a common time

base if they are in

Capture/Compare or PWM

modes.

Timer1 and Timer2 are used

for Capture and Compare or

PWM operations for ECCP1

and ECCP2 only (depending

on the mode selected for each

module). Both modules may

use a timer as a common time

base if they are both in

Capture/Compare or PWM

modes.

The other modules use either

Timer3 or Timer4. Modules

may share either timer

resource as a common time

base if they are in

Capture/Compare or PWM

modes.

Timer3 is used for all Capture

and Compare operations for

all CCP modules. Timer4 is

used for PWM operations for

all CCP modules. Modules

may share either timer

resource as a common time

base.

Timer1 and Timer2 are not

available.

PIC18F87J50 FAMILY

17.2 Capture Mode

In Capture mode, the CCPRxH:CCPRxL register pair

captures the 16-bit value of the TMR1 or TMR3

registers when an event occurs on the corresponding

CCPx pin. An event is defined as one of the following:

• every falling edge

• every rising edge

• every 4th rising edge

• every 16th rising edge

The event is selected by the mode select bits,

CCPxM3:CCPxM0 (CCPxCON<3:0>). When a capture

is made, the interrupt request flag bit, CCPxIF, is set; it

must be cleared in software. If another capture occurs

before the value in register CCPRx is read, the old

captured value is overwritten by the new captured value.

17.2.1 CCPx PIN CONFIGURATION

In Capture mode, the appropriate CCPx pin should be

configured as an input by setting the corresponding

TRIS direction bit.

17.2.2 TIMER1/TIMER3 MODE SELECTION

The timers that are to be used with the capture feature

(Timer1 and/or Timer3) must be running in Timer mode or

Synchronized Counter mode. In Asynchronous Counter

mode, the capture operation will not work. The timer to be

used with each CCP module is selected in the T3CON

Resources”).

17.2.3 SOFTWARE INTERRUPT

When the Capture mode is changed, a false capture

interrupt may be generated. The user should keep the

CCPxIE interrupt enable bit clear to avoid false

interrupts. The interrupt flag bit, CCPxIF, should also be

cleared following any such change in operating mode.

17.2.4 CCP PRESCALER

There are four prescaler settings in Capture mode.

They are specified as part of the operating mode

selected by the mode select bits (CCPxM3:CCPxM0).

Whenever the CCPx module is turned off or Capture

mode is disabled, the prescaler counter is cleared. This

means that any Reset will clear the prescaler counter.

Switching from one capture prescaler to another may

generate an interrupt. Also, the prescaler counter will

not be cleared; therefore, the first capture may be from

a non-zero prescaler. Example 17-1 shows the

recommended method for switching between capture

prescalers. This example also clears the prescaler

counter and will not generate the “false” interrupt.

EXAMPLE 17-1: CHANGING BETWEEN

CAPTURE PRESCALERS

(CCP5 SHOWN)

FIGURE 17-2: CAPTURE MODE OPERATION BLOCK DIAGRAM

Note: If RG4/CCP5 is configured as an output, a

write to the port can cause a capture

condition.

CLRF CCP5CON ; Turn CCP module off

MOVLW NEW_CAPT_PS ; Load WREG with the

; new prescaler mode

; value and CCP ON

MOVWF CCP5CON ; Load CCP5CON with

; this value

CCPR4H CCPR4L

TMR1H TMR1L

Set CCP4IF

TMR3

Enable

Q1:Q4

CCP4CON<3:0>

CCP4 pin

Prescaler

÷ 1, 4, 16

and

Edge Detect

TMR1

Enable

T3CCP2

CCPR5H CCPR5L

TMR1H TMR1L

Set CCP5IF

TMR3

Enable

CCP5CON<3:0>

CCP5 pin

Prescaler

÷ 1, 4, 16

TMR3H TMR3L

TMR1

Enable

T3CCP2

T3CCP1

T3CCP2

T3CCP1

TMR3H TMR3L

and

Edge Detect

PIC18F87J50 FAMILY

17.3 Compare Mode

In Compare mode, the 16-bit CCPRx register value is

constantly compared against either the TMR1 or TMR3

can be:

• driven high

• driven low

• toggled (high-to-low or low-to-high)

• remains unchanged (that is, reflects the state of

the I/O latch)

The action on the pin is based on the value of the mode

select bits (CCPxM3:CCPxM0). At the same time, the

interrupt flag bit, CCPxIF, is set.

17.3.1 CCPx PIN CONFIGURATION

The user must configure the CCPx pin as an output by

clearing the appropriate TRIS bit.

17.3.2 TIMER1/TIMER3 MODE SELECTION

Timer1 and/or Timer3 must be running in Timer mode

or Synchronized Counter mode if the CCPx module is

using the compare feature. In Asynchronous Counter

mode, the compare operation may not work.

17.3.3 SOFTWARE INTERRUPT MODE

When the Generate Software Interrupt mode is chosen

(CCPxM3:CCPxM0 = 1010), the corresponding CCPx

pin is not affected. Only a CCP interrupt is generated,

if enabled and the CCPxIE bit is set.

FIGURE 17-3: COMPARE MODE OPERATION BLOCK DIAGRAM

Note: Clearing the CCP5CON register will force

the RG4 compare output latch (depend-

ing on device configuration) to the default

low level. This is not the PORTB or

PORTC I/O data latch.

CCPR4H CCPR4L

TMR1H TMR1L

Comparator QS

Output

Logic

Set CCP4IF

CCP4 pin

TRIS

CCP4CON<3:0>

Output Enable

TMR3H TMR3L

CCPR5H CCPR5L

Comparator

T3CCP2

T3CCP1

Set CCP5IF

Compare

Output

Logic

CCP5 pin

TRIS

CCP5CON<3:0>

Output Enable

Match

Compare

Match

PIC18F87J50 FAMILY

TABLE 17-2: REGISTERS ASSOCIATED WITH CAPTURE, COMPARE, TIMER1 AND TIMER3

Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Reset

Values

on Page:

INTCON GIE/GIEH PEIE/GIEL TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 61

RCON IPEN —CM RI TO PD POR BOR 62

PIR1 PMPIF ADIF RC1IF TX1IF SSP1IF CCP1IF TMR2IF TMR1IF 64

PIE1 PMPIE ADIE RC1IE TX1IE SSP1IE CCP1IE TMR2IE TMR1IE 64

IPR1 PMPIP ADIP RC1IP TX1IP SSP1IP CCP1IP TMR2IP TMR1IP 64

PIR2 OSCFIF CM2IF CM1IF USBIF BCL1IF LVDIF TMR3IF CCP2IF 64

PIE2 OSCFIE CM2IE CM1IE USBIE BCL1IE LVDIE TMR3IE CCP2IE 64

IPR2 OSCFIP CM2IP CM1IP USBIP BCL1IP LVDIP TMR3IP CCP2IP 64

PIR3 SSP2IF BCL2IF RC2IF TX2IF TMR4IF CCP5IF CCP4IF CCP3IF 64

PIE3 SSP2IE BCL2IE RC2IE TX2IE TMR4IE CCP5IE CCP4IE CCP3IE 64

IPR3 SSP2IP BCL2IP RC2IP TX2IP TMR4IP CCP5IP CCP4IP CCP3IP 64

TRISG — — — TRISG4 TRISG3 TRISG2 TRISG1 TRISG0 64

TMR1L(1) Timer1 Register Low Byte 62

TMR1H(1) Timer1 Register High Byte 62

ODCON1(2) — — — CCP5OD CCP4OD ECCP3OD ECCP2OD ECCP1OD 62

T1CON(1) RD16 T1RUN T1CKPS1 T1CKPS0 T1OSCEN T1SYNC TMR1CS TMR1ON 62

TMR3H Timer3 Register High Byte 65

TMR3L Timer3 Register Low Byte 65

T3CON RD16 T3CCP2 T3CKPS1 T3CKPS0 T3CCP1 T3SYNC TMR3CS TMR3ON 65

CCPR4L Capture/Compare/PWM Register 4 Low Byte 65

CCPR4H Capture/Compare/PWM Register 4 High Byte 65

CCPR5L Capture/Compare/PWM Register 5 Low Byte 65

CCPR5H Capture/Compare/PWM Register 5 High Byte 65

CCP4CON —— DC4B1 DC4B0 CCP4M3 CCP4M2 CCP4M1 CCP4M0 65

CCP5CON —— DC5B1 DC5B0 CCP5M3 CCP5M2 CCP5M1 CCP5M0 65

Legend: — = unimplemented, read as ‘0’. Shaded cells are not used by Capture/Compare, Timer1 or Timer3.

Note 1: Default (legacy) SFR at this address, available when WDTCON<4> = 0.

2: Configuration SFR, overlaps with default SFR at this address; available only when WDTCON<4> = 1.

PIC18F87J50 FAMILY

17.4 PWM Mode

In Pulse-Width Modulation (PWM) mode, the CCPx pin

produces up to a 10-bit resolution PWM output. Since

the CCP4 and CCP5 pins are multiplexed with a

PORTG data latch, the appropriate TRISG bit must be

cleared to make the CCP4 or CCP5 pin an output.

Figure 17-4 shows a simplified block diagram of the

CCP module in PWM mode.

For a step-by-step procedure on how to set up a CCP

module for PWM operation, see Section 17.4.3

“Setup for PWM Operation”.

FIGURE 17-4: SIMPLIFIED PWM BLOCK

DIAGRAM

A PWM output (Figure 17-5) has a time base (period)

and a time that the output stays high (duty cycle).

The frequency of the PWM is the inverse of the

period (1/period).

FIGURE 17-5: PWM OUTPUT

17.4.1 PWM PERIOD

The PWM period is specified by writing to the PR2

(PR4) register. The PWM period can be calculated

using Equation 17-1:

EQUATION 17-1:

PWM frequency is defined as 1/[PWM period].

When TMR2 (TMR4) is equal to PR2 (PR4), the

following three events occur on the next increment

cycle:

• TMR2 (TMR4) is cleared

• The CCPx pin is set (exception: if PWM duty

cycle = 0%, the CCPx pin will not be set)

• The PWM duty cycle is latched from CCPRxL into

CCPRxH

17.4.2 PWM DUTY CYCLE

The PWM duty cycle is specified by writing to the

CCPRxL register and to the CCPxCON<5:4> bits. Up

to 10-bit resolution is available. The CCPRxL contains

the eight MSbs and the CCPxCON<5:4> contains the

two LSbs. This 10-bit value is represented by

CCPRxL:CCPxCON<5:4>. Equation 17-2 is used to

calculate the PWM duty cycle in time.

EQUATION 17-2:

CCPRxL and CCPxCON<5:4> can be written to at any

time, but the duty cycle value is not latched into

CCPRxH until after a match between PR2 (PR4) and

TMR2 (TMR4) occurs (i.e., the period is complete). In

PWM mode, CCPRxH is a read-only register.

Note: Clearing the CCP4CON or CCP5CON

latch (depending on device configuration)

to the default low level. This is not the

PORTG I/O data latch.

CCPRxL

Comparator

PRx

CCPxCON<5:4>

RCCPx

TRIS

Output Enable

CCPRxH

TMRx

2 LSbs latched

from Q clocks

Reset

Match

TMRx = PRx

Latch

(1)

Note 1: The two LSbs of the Duty Cycle register are held by a

2-bit latch that is part of the module’s hardware. It is

physically separate from the CCPRx registers.

Duty Cycle Register

Set CCPx pin

Duty Cycle

Period

Duty Cycle

TMR2 (TMR4) = PR2 (TMR4)

TMR2 (TMR4) = Duty Cycle

TMR2 (TMR4) = PR2 (PR4)

Note: The Timer2 and Timer 4 postscalers (see

Section 14.0 “Timer2 Module” and

Section 16.0 “Timer4 Module”) are not

used in the determination of the PWM

frequency. The postscaler could be used

to have a servo update rate at a different

frequency than the PWM output.

PWM Period = [(PR2) + 1] • 4 • TOSC •

(TMR2 Prescale Value)

PWM Duty Cycle = (CCPRXL:CCPXCON<5:4>) •

TOSC • (TMR2 Prescale Value)

PIC18F87J50 FAMILY

The CCPRxH register and a 2-bit internal latch are

used to double-buffer the PWM duty cycle. This

double-buffering is essential for glitchless PWM

operation.

When the CCPRxH and 2-bit latch match TMR2

(TMR4), concatenated with an internal 2-bit Q clock or

2 bits of the TMR2 (TMR4) prescaler, the CCPx pin is

cleared.

The maximum PWM resolution (bits) for a given PWM

frequency is given by Equation 17-3:

EQUATION 17-3:

17.4.3 SETUP FOR PWM OPERATION

The following steps should be taken when configuring

the CCP module for PWM operation:

1. Set the PWM period by writing to the PR2 (PR4)

2. Set the PWM duty cycle by writing to the

CCPRxL register and CCPxCON<5:4> bits.

3. Make the CCPx pin an output by clearing the

appropriate TRIS bit.

4. Set the TMR2 (TMR4) prescale value, then

enable Timer2 (Timer4) by writing to T2CON

(T4CON).

5. Configure the CCPx module for PWM operation.

TABLE 17-3: EXAMPLE PWM FREQUENCIES AND RESOLUTIONS AT 40 MHz

Note: If the PWM duty cycle value is longer than

the PWM period, the CCPx pin will not be

cleared.

log(FPWM

log(2)

FOSC )bitsPWM Resolution (max) =

PWM Frequency 2.44 kHz 9.77 kHz 39.06 kHz 156.25 kHz 312.50 kHz 416.67 kHz

Timer Prescaler (1, 4, 16)1641111

PR2 Value FFh FFh FFh 3Fh 1Fh 17h

Maximum Resolution (bits) 10 10 10 8 7 6.58

PIC18F87J50 FAMILY

TABLE 17-4: REGISTERS ASSOCIATED WITH PWM, TIMER2 AND TIMER4

Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Reset

Values

on Page:

INTCON GIE/GIEH PEIE/GIEL TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 61

RCON IPEN —CM RI TO PD POR BOR 62

PIR1 PMPIF ADIF RC1IF TX1IF SSP1IF CCP1IF TMR2IF TMR1IF 64

PIE1 PMPIE ADIE RC1IE TX1IE SSP1IE CCP1IE TMR2IE TMR1IE 64

IPR1 PMPIP ADIP RC1IP TX1IP SSP1IP CCP1IP TMR2IP TMR1IP 64

PIR3 SSP2IF BCL2IF RC2IF TX2IF TMR4IF CCP5IF CCP4IF CCP3IF 64

PIE3 SSP2IE BCL2IE RC2IE TX2IE TMR4IE CCP5IE CCP4IE CCP3IE 64

IPR3 SSP2IP BCL2IP RC2IP TX2IP TMR4IP CCP5IP CCP4IP CCP3IP 64

TRISG — — — TRISG4 TRISG3 TRISG2 TRISG1 TRISG0 64

TMR2(1) Timer2 Register 62

PR2(1) Timer2 Period Register 62

T2CON — T2OUTPS3 T2OUTPS2 T2OUTPS1 T2OUTPS0 TMR2ON T2CKPS1 T2CKPS0 62

TMR4 Timer4 Register 65

PR4(1) Timer4 Period Register 65

T4CON — T4OUTPS3 T4OUTPS2 T4OUTPS1 T4OUTPS0 TMR4ON T4CKPS1 T4CKPS0 65

CCPR4L Capture/Compare/PWM Register 4 Low Byte 65

CCPR4H Capture/Compare/PWM Register 4 High Byte 65

CCPR5L Capture/Compare/PWM Register 5 Low Byte 65

CCPR5H Capture/Compare/PWM Register 5 High Byte 65

CCP4CON —— DC4B1 DC4B0 CCP4M3 CCP4M2 CCP4M1 CCP4M0 65

CCP5CON —— DC5B1 DC5B0 CCP5M3 CCP5M2 CCP5M1 CCP5M0 65

ODCON1(2) — — — CCP5OD CCP4OD ECCP3OD ECCP2OD ECCP1OD 62

Legend: — = unimplemented, read as ‘0’. Shaded cells are not used by PWM, Timer2 or Timer4.

Note 1: Default (legacy) SFR at this address, available when WDTCON<4> = 0.

2: Configuration SFR, overlaps with default SFR at this address; available only when WDTCON<4> = 1.

PIC18F87J50 FAMILY

18.0 ENHANCED CAPTURE/

COMPARE/PWM (ECCP)

MODULE

In the PIC18F87J10 family of devices, three of the CCP

modules are implemented as standard CCP modules

with Enhanced PWM capabilities. These include the

provision for 2 or 4 output channels, user-selectable

polarity, dead-band control and automatic shutdown

and restart. The Enhanced features are discussed in

detail in Section 18.4 “Enhanced PWM Mode”.

Capture, Compare and single-output PWM functions of

the ECCP module are the same as described for the

standard CCP module.

The control register for the Enhanced CCP module is

shown in Register 18-1. It differs from the CCP4CON/

CCP5CON registers in that the two Most Significant

bits are implemented to control PWM functionality.

In addition to the expanded range of modes available

through the Enhanced CCPxCON register, the ECCP

modules each have two additional registers associated

with Enhanced PWM operation and auto-shutdown

features. They are:

• ECCPxDEL (ECCPx PWM Delay)

• ECCPxAS (ECCPx Auto-Shutdown Control)

R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

PxM1 PxM0 DCxB1 DCxB0 CCPxM3 CCPxM2 CCPxM1 CCPxM0

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7-6 PxM1:PxM0: Enhanced PWM Output Configuration bits

If CCPxM3:CCPxM2 = 00, 01, 10:

xx = PxA assigned as Capture/Compare input/output; PxB, PxC, PxD assigned as port pins

If CCPxM3:CCPxM2 = 11:

00 = Single output: PxA modulated; PxB, PxC, PxD assigned as port pins

01 = Full-bridge output forward: P1D modulated; P1A active; P1B, P1C inactive

10 = Half-bridge output: P1A, P1B modulated with dead-band control; P1C, P1D assigned as port pins

11 = Full-bridge output reverse: P1B modulated; P1C active; P1A, P1D inactive

bit 5-4 DCxB1:DCxB0: PWM Duty Cycle bit 1 and bit 0

Capture mode:

Unused.

Compare mode:

Unused.

PWM mode:

These bits are the two LSbs of the 10-bit PWM duty cycle. The eight MSbs of the duty cycle are found in CCPRxL.

bit 3-0 CCPxM3:CCPxM0: ECCPx Module Mode Select bits

0000 = Capture/Compare/PWM off (resets ECCPx module)

0001 = Reserved

0010 = Compare mode: toggle output on match

0011 = Capture mode

0100 = Capture mode: every falling edge

0101 = Capture mode: every rising edge

0110 = Capture mode: every 4th rising edge

0111 = Capture mode, every 16th rising edge

1000 = Compare mode: initialize ECCPx pin low; set output on compare match (set CCPxIF)

1001 = Compare mode: initialize ECCPx pin high; clear output on compare match (set CCPxIF)

1010 = Compare mode: generate software interrupt only; ECCPx pin reverts to I/O state

1011 = Compare mode: trigger special event (ECCPx resets TMR1 or TMR3, sets CCPxIF bit, ECCP2

trigger also starts A/D conversion if A/D module is enabled)(1)

1100 = PWM mode: PxA, PxC active-high; PxB, PxD active-high

1101 = PWM mode: PxA, PxC active-high; PxB, PxD active-low

1110 = PWM mode: PxA, PxC active-low; PxB, PxD active-high

1111 = PWM mode: PxA, PxC active-low; PxB, PxD active-low

Note 1: Implemented only for ECCP1 and ECCP2; same as ‘1010’ for ECCP3.

PIC18F87J50 FAMILY

18.1 ECCP Outputs and Configuration

Each of the Enhanced CCP modules may have up to

four PWM outputs, depending on the selected operat-

ing mode. These outputs, designated PxA through

PxD, are multiplexed with various I/O pins. Some

ECCP pin assignments are constant, while others

change based on device configuration. For those pins

that do change, the controlling bits are:

• CCP2MX Configuration bit

• ECCPMX Configuration bit (80-pin devices only)

• Program Memory Operating mode, set by the

EMB Configuration bits (80-pin devices only)

The pin assignments for the Enhanced CCP modules

are summarized in Table 18-1, Table 18-2 and

Table 18-3. To configure the I/O pins as PWM outputs,

the proper PWM mode must be selected by setting the

PxMx and CCPxMx bits (CCPxCON<7:6> and <3:0>,

respectively). The appropriate TRIS direction bits for

the corresponding port pins must also be set as

outputs.

18.1.1 ECCP1/ECCP3 OUTPUTS AND

PROGRAM MEMORY MODE

In 80-pin devices, the use of Extended Microcontroller

mode has an indirect effect on the use of ECCP1 and

ECCP3 in Enhanced PWM modes. By default, PWM

outputs, P1B/P1C and P3B/P3C, are multiplexed to

PORTE pins along with the high-order byte of the

External Memory Bus. When the bus is active in

Extended Microcontroller mode, it overrides the

Enhanced CCP outputs and makes them unavailable.

Because of this, ECCP1 and ECCP3 can only be used

in compatible (single output) PWM modes when the

device is in Extended Microcontroller mode and default

pin configuration.

An exception to this configuration is when a 12-bit

address width is selected for the external bus

(EMB1:EMB0 Configuration bits = 01). In this case, the

upper pins of PORTE continue to operate as digital I/O,

even when the external bus is active. P1B/P1C and

P3B/P3C remain available for use as Enhanced PWM

outputs.

If an application requires the use of additional PWM

outputs during enhanced microcontroller operation, the

P1B/P1C and P3B/P3C outputs can be reassigned to

the upper bits of PORTH. This is done by clearing the

ECCPMX Configuration bit.

18.1.2 ECCP2 OUTPUTS AND PROGRAM

MEMORY MODES

For 80-pin devices, the program memory mode of the

device (Section 5.1.3 “PIC18F87J50 Family Program

Memory Modes”) also impacts pin multiplexing for the

module. The ECCP2 input/output (ECCP2/P2A) can be

multiplexed to one of three pins. The default assignment

(CCP2MX Configuration bit is set) for all devices is

RC1. Clearing CCP2MX reassigns ECCP2/P2A to RE7.

An additional option exists for 80-pin devices. When

these devices are operating in Microcontroller mode,

the multiplexing options described above still apply. In

Extended Microcontroller mode, clearing CCP2MX

reassigns ECCP2/P2A to RB3.

Changing the pin assignment of ECCP2 does not auto-

matically change any requirements for configuring the

port pin. Users must always verify that the appropriate

TRIS register is configured correctly for ECCP2

operation regardless of where it is located.

18.1.3 USE OF CCP4 AND CCP5 WITH

ECCP1 AND ECCP3

Only the ECCP2 module has four dedicated output pins

that are available for use. Assuming that the I/O ports

or other multiplexed functions on those pins are not

needed, they may be used whenever needed without

interfering with any other CCP module.

ECCP1 and ECCP3, on the other hand, only have

three dedicated output pins: ECCPx/PxA, PxB and

PxC. Whenever these modules are configured for

Quad PWM mode, the pin normally used for CCP4 or

CCP5 becomes the PxD output pins for ECCP3 and

ECCP1, respectively. The CCP4 and CCP5 modules

remain functional but their outputs are overridden.

18.1.4 ECCP MODULES AND TIMER

RESOURCES

Like the standard CCP modules, the ECCP modules

can utilize Timers 1, 2, 3 or 4, depending on the mode

selected. Timer1 and Timer3 are available for modules

in Capture or Compare modes, while Timer2 and

Timer4 are available for modules in PWM mode.

Additional details on timer resources are provided in

Section 17.1.1 “CCP Modules and Timer

Resources”.

18.1.5 OPEN-DRAIN OUTPUT OPTION

When operating in compare or standard PWM modes,

the drivers for the ECCPx pins can be optionally config-

ured as open-drain outputs. This feature allows the

voltage level on the pin to be pulled to a higher level

through an external pull-up resistor, and allows the out-

put to communicate with external circuits without the

need for additional level shifters. For more information,

see Section 10.1.4 “Open-Drain Outputs”.

The open-drain output option is controlled by the bits in

the ODCON1 register. Setting the appropriate bit con-

figures the pin for the corresponding module for

open-drain operation. The ODCON1 memory shares

the same address space as of TMR1H. The ODCON1

the WDTCON register (WDTCON<4>).

PIC18F87J50 FAMILY

TABLE 18-1: PIN CONFIGURATIONS FOR ECCP1

TABLE 18-2: PIN CONFIGURATIONS FOR ECCP2

ECCP Mode CCP1CON

Configuration RC2 RE6 RE5 RG4 RH7 RH6

All Feature1 Devices:

Compatible CCP 00xx 11xx ECCP1 RE6 RE5 RG4/CCP5 N/A N/A

Dual PWM 10xx 11xx P1A P1B RE5 RG4/CCP5 N/A N/A

Quad PWM(1) x1xx 11xx P1A P1B P1C P1D N/A N/A

PIC18F8XJ5X Devices, ECCPMX = 0, Microcontroller mode:

Compatible CCP 00xx 11xx ECCP1 RE6/AD14 RE5/AD13 RG4/CCP5 RH7/AN15 RH6/AN14

Dual PWM 10xx 11xx P1A RE6/AD14 RE5/AD13 RG4/CCP5 P1B RH6/AN14

Quad PWM(1) x1xx 11xx P1A RE6/AD14 RE5/AD13 P1D P1B P1C

PIC18F8XJ5X Devices, ECCPMX = 1, Extended Microcontroller mode, 16-Bit or 20-Bit Address Width:

Compatible CCP 00xx 11xx ECCP1 RE6/AD14 RE5/AD13 RG4/CCP5 RH7/AN15 RH6/AN14

PIC18F8XJ5X Devices, ECCPMX = 1,

Microcontroller mode or Extended Microcontroller mode, 12-Bit Address Width:

Compatible CCP 00xx 11xx ECCP1 RE6/AD14 RE5/AD13 RG4/CCP5 RH7/AN15 RH6/AN14

Dual PWM 10xx 11xx P1A P1B RE5/AD13 RG4/CCP5 RH7/AN15 RH6/AN14

Quad PWM(1) x1xx 11xx P1A P1B P1C P1D RH7/AN15 RH6/AN14

Legend: x = Don’t care, N/A = Not Available. Shaded cells indicate pin assignments not used by ECCP1 in a given mode.

Note 1: With ECCP1 in Quad PWM mode, CCP5’s output is overridden by P1D; otherwise, CCP5 is fully operational.

ECCP Mode CCP2CON

Configuration RB3 RC1 RE7 RE2 RE1 RE0

All Devices, CCP2MX = 1, Either Operating mode:

Compatible CCP 00xx 11xx RB3/INT3 ECCP2 RE7 RE2 RE1 RE0

Dual PWM 10xx 11xx RB3/INT3 P2A RE7 P2B RE1 RE0

Quad PWM x1xx 11xx RB3/INT3 P2A RE7 P2B P2C P2D

All Devices, CCP2MX = 0, Microcontroller mode:

Compatible CCP 00xx 11xx RB3/INT3 RC1/T1OS1 ECCP2 RE2 RE1 RE0

Dual PWM 10xx 11xx RB3/INT3 RC1/T1OS1 P2A P2B RE1 RE0

Quad PWM x1xx 11xx RB3/INT3 RC1/T1OS1 P2A P2B P2C P2D

PIC18F8XJ5X Devices, CCP2MX = 0, Extended Microcontroller mode:

Compatible CCP 00xx 11xx ECCP2 RC1/T1OS1 RE7/AD15 RE2/CS RE1/WR RE0/RD

Dual PWM 10xx 11xx P2A RC1/T1OS1 RE7/AD15 P2B RE1/WR RE0/RD

Quad PWM x1xx 11xx P2A RC1/T1OS1 RE7/AD15 P2B P2C P2D

Legend: x = Don’t care. Shaded cells indicate pin assignments not used by ECCP2 in a given mode.

PIC18F87J50 FAMILY

TABLE 18-3: PIN CONFIGURATIONS FOR ECCP3

18.2 Capture and Compare Modes

Except for the operation of the Special Event Trigger

discussed below, the Capture and Compare modes of

the ECCP module are identical in operation to that of

CCP4. These are discussed in detail in Section 17.2

“Capture Mode” and Section 17.3 “Compare

Mode”.

18.2.1 SPECIAL EVENT TRIGGER

ECCP1 and ECCP2 incorporate an internal hardware

trigger that is generated in Compare mode on a match

between the CCPRx register pair and the selected

timer. This can be used in turn to initiate an action. This

mode is selected by setting CCPxCON<3:0> to ‘1011’.

The Special Event Trigger output of either ECCP1 or

ECCP2 resets the TMR1 or TMR3 register pair, depend-

ing on which timer resource is currently selected. This

allows the CCPRx register pair to effectively be a 16-bit

programmable period register for Timer1 or Timer3. In

addition, the ECCP2 Special Event Trigger will also start

an A/D conversion if the A/D module is enabled.

Special Event Triggers are not implemented for

ECCP3, CCP4 or CCP5. Selecting the Special Event

Trigger mode for these modules has the same effect as

selecting the Compare with Software Interrupt mode

(CCPxM3:CCPxM0 = 1010).

18.3 Standard PWM Mode

When configured in Single Output mode, the ECCP

module functions identically to the standard CCP

module in PWM mode, as described in Section 17.4

“PWM Mode”. This is also sometimes referred to as

“Compatible CCP” mode as in Tables 18-1

through 18-3.

ECCP Mode CCP3CON

Configuration RG0 RE4 RE3 RG3 RH5 RH4

Feature1 Devices:

Compatible CCP 00xx 11xx ECCP3 RE4 RE3 RG3/CCP4 N/A N/A

Dual PWM 10xx 11xx P3A P3B RE3 RG3/CCP4 N/A N/A

Quad PWM(1) x1xx 11xx P3A P3B P3C P3D N/A N/A

PIC18F8XJ5X Devices, ECCPMX = 0, Microcontroller mode:

Compatible CCP 00xx 11xx ECCP3 RE6/AD14 RE5/AD13 RG3/CCP4 RH7/AN15 RH6/AN14

Dual PWM 10xx 11xx P3A RE6/AD14 RE5/AD13 RG3/CCP4 P3B RH6/AN14

Quad PWM(1) x1xx 11xx P3A RE6/AD14 RE5/AD13 P3D P3B P3C

PIC18F8XJ5X Devices, ECCPMX = 1, Extended Microcontroller mode, 16-Bit or 20-Bit Address Width:

Compatible CCP 00xx 11xx ECCP3 RE6/AD14 RE5/AD13 RG3/CCP4 RH7/AN15 RH6/AN14

PIC18F8XJ5X Devices, ECCPMX = 1,

Microcontroller mode or Extended Microcontroller mode, 12-Bit Address Width:

Compatible CCP 00xx 11xx ECCP3 RE4/AD12 RE3/AD11 RG3/CCP4 RH5/AN13 RH4/AN12

Dual PWM 10xx 11xx P3A P3B RE3/AD11 RG3/CCP4 RH5/AN13 RH4/AN12

Quad PWM(1) x1xx 11xx P3A P3B P3C P3D RH5/AN13 RH4/AN12

Legend: x = Don’t care, N/A = Not Available. Shaded cells indicate pin assignments not used by ECCP3 in a given mode.

Note 1: With ECCP3 in Quad PWM mode, CCP4’s output is overridden by P1D; otherwise, CCP4 is fully operational.

Note: The Special Event Trigger from ECCP2

will not set the Timer1 or Timer3 interrupt

flag bits.

Note: When setting up single output PWM

operations, users are free to use either of

the processes described in Section 17.4.3

“Setup for PWM Operation” or

Section 18.4.9 “Setup for PWM Opera-

tion”. The latter is more generic but will

work for either single or multi-output PWM.

PIC18F87J50 FAMILY

18.4 Enhanced PWM Mode

The Enhanced PWM mode provides additional PWM

output options for a broader range of control applica-

tions. The module is a backward compatible version of

the standard CCP module and offers up to four outputs,

designated PxA through PxD. Users are also able to

select the polarity of the signal (either active-high or

active-low). The module’s output mode and polarity

are configured by setting the PxM1:PxM0 and

CCPxM3CCPxM0 bits of the CCPxCON register

(CCPxCON<7:6> and CCPxCON<3:0>, respectively).

For the sake of clarity, Enhanced PWM mode operation

is described generically throughout this section with

respect to the ECCP1 and TMR2 modules. Control reg-

ister names are presented in terms of ECCP1. All three

Enhanced modules, as well as the two timer resources,

can be used interchangeably and function identically.

TMR2 or TMR4 can be selected for PWM operation by

selecting the proper bits in T3CON.

Figure 18-1 shows a simplified block diagram of PWM

operation. All control registers are double-buffered and

are loaded at the beginning of a new PWM cycle (the

period boundary when Timer2 resets) in order to

prevent glitches on any of the outputs. The exception is

the ECCPx PWM Delay register, ECCPxDEL, which is

loaded at either the duty cycle boundary or the bound-

ary period (whichever comes first). Because of the

buffering, the module waits until the assigned timer

resets instead of starting immediately. This means that

Enhanced PWM waveforms do not exactly match the

standard PWM waveforms, but are instead offset by

one full instruction cycle (4 TOSC).

As before, the user must manually configure the

appropriate TRIS bits for output.

18.4.1 PWM PERIOD

The PWM period is specified by writing to the PR2

equation:

EQUATION 18-1:

PWM frequency is defined as 1/[PWM period]. When

TMR2 is equal to PR2, the following three events occur

on the next increment cycle:

•TMR2 is cleared

• The ECCP1 pin is set (if PWM duty cycle = 0%,

the ECCP1 pin will not be set)

• The PWM duty cycle is copied from CCPR1L into

CCPR1H

FIGURE 18-1: SIMPLIFIED BLOCK DIAGRAM OF THE ENHANCED PWM MODULE

Note: The Timer2 postscaler (see Section 14.0

“Timer2 Module”) is not used in the

determination of the PWM frequency. The

postscaler could be used to have a servo

update rate at a different frequency than

the PWM output.

PWM Period = [(PR2) + 1] • 4 • TOSC •

(TMR2 Prescale Value)

CCPR1L

CCPR1H (Slave)

Comparator

TMR2

Comparator

PR2

(Note 1)

Duty Cycle Registers CCP1CON<5:4>

Clear Timer,

set ECCP1 pin and

latch D.C.

Note: The 8-bit TMR2 register is concatenated with the 2-bit internal Q clock, or 2 bits of the prescaler, to create the 10-bit time

base.

TRISx<x>

ECCP1/P1A

TRISx<x>

P1B

TRISx<x>

P1D

Output

Controller

P1M1<1:0>

CCP1M<3:0>

ECCP1DEL

ECCP1/P1A

P1B

P1C

P1D

P1C

PIC18F87J50 FAMILY

18.4.2 PWM DUTY CYCLE

The PWM duty cycle is specified by writing to the

CCPR1L register and to the CCP1CON<5:4> bits. Up

to 10-bit resolution is available. The CCPR1L contains

the eight MSbs and the CCP1CON<5:4> contains the

two LSbs. This 10-bit value is represented by

CCPR1L:CCP1CON<5:4>. The PWM duty cycle is

calculated by the following equation:

EQUATION 18-2:

CCPR1L and CCP1CON<5:4> can be written to at any

time but the duty cycle value is not copied into

CCPR1H until a match between PR2 and TMR2 occurs

(i.e., the period is complete). In PWM mode, CCPR1H

is a read-only register.

The CCPR1H register and a 2-bit internal latch are

used to double-buffer the PWM duty cycle. This

double-buffering is essential for glitchless PWM opera-

tion. When the CCPR1H and 2-bit latch match TMR2,

concatenated with an internal 2-bit Q clock or two bits

of the TMR2 prescaler, the ECCP1 pin is cleared. The

maximum PWM resolution (bits) for a given PWM

frequency is given by the equation:

EQUATION 18-3:

18.4.3 PWM OUTPUT CONFIGURATIONS

The P1M1:P1M0 bits in the CCP1CON register allow

one of four configurations:

• Single Output

• Half-Bridge Output

• Full-Bridge Output, Forward mode

• Full-Bridge Output, Reverse mode

The Single Output mode is the standard PWM mode

discussed in Section 18.4 “Enhanced PWM Mode”.

The Half-Bridge and Full-Bridge Output modes are

covered in detail in the sections that follow.

The general relationship of the outputs in all

configurations is summarized in Figure 18-2.

TABLE 18-4: EXAMPLE PWM FREQUENCIES AND RESOLUTIONS AT 40 MHz

PWM Duty Cycle = (CCPR1L:CCP1CON<5:4>) •

TOSC • (TMR2 Prescale Value)

( )

PWM Resolution (max) =

FOSC

FPWM

log

log(2) bits

Note: If the PWM duty cycle value is longer than

the PWM period, the ECCP1 pin will not

be cleared.

PWM Frequency 2.44 kHz 9.77 kHz 39.06 kHz 156.25 kHz 312.50 kHz 416.67 kHz

Timer Prescaler (1, 4, 16)1641111

PR2 Value FFh FFh FFh 3Fh 1Fh 17h

Maximum Resolution (bits) 10 10 10 8 7 6.58

PIC18F87J50 FAMILY

FIGURE 18-2: PWM OUTPUT RELATIONSHIPS (ACTIVE-HIGH STATE)

FIGURE 18-3: PWM OUTPUT RELATIONSHIPS (ACTIVE-LOW STATE)

Period

SIGNAL PR2 + 1

CCP1CON<7:6>

P1A Modulated

P1B Modulated

P1A Active

P1B Inactive

P1C Inactive

P1D Modulated

P1A Inactive

P1B Modulated

P1C Active

P1D Inactive

Duty

Cycle

(Single Output)

(Half-Bridge)

(Full-Bridge,

Forward)

(Full-Bridge,

Reverse)

Delay(1) Delay(1)

Period

SIGNAL PR2 + 1

CCP1CON<7:6> Duty

Cycle

(Single Output)

(Half-Bridge)

(Full-Bridge,

Forward)

(Full-Bridge,

Reverse)

Delay(1) Delay(1)

Relationships:

• Period = 4 * TOSC * (PR2 + 1) * (TMR2 Prescale Value)

• Duty Cycle = T

OSC * (CCPR1L<7:0>:CCP1CON<5:4>) * (TMR2 Prescale Value)

• Delay = 4 * T

OSC * (ECCP1DEL<6:0>)

Note 1: Dead-band delay is programmed using the ECCP1DEL register (Section 18.4.6 “Programmable

Dead-Band Delay”).

P1A Modulated

P1B Modulated

P1A Active

P1B Inactive

P1C Inactive

P1D Modulated

P1A Inactive

P1B Modulated

P1C Active

P1D Inactive

PIC18F87J50 FAMILY

18.4.4 HALF-BRIDGE MODE

In the Half-Bridge Output mode, two pins are used as

outputs to drive push-pull loads. The PWM output

signal is output on the P1A pin, while the complemen-

tary PWM output signal is output on the P1B pin

(Figure 18-4). This mode can be used for half-bridge

applications, as shown in Figure 18-5, or for full-bridge

applications, where four power switches are being

modulated with two PWM signals.

In Half-Bridge Output mode, the programmable

dead-band delay can be used to prevent shoot-through

current in half-bridge power devices. The value of bits

P1DC6:P1DC0 sets the number of instruction cycles

before the output is driven active. If the value is greater

than the duty cycle, the corresponding output remains

inactive during the entire cycle. See Section 18.4.6

“Programmable Dead-Band Delay” for more details

on dead-band delay operations.

Since the P1A and P1B outputs are multiplexed with

the PORTC<2> and PORTE<6> data latches, the

TRISC<2> and TRISE<6> bits must be cleared to

configure P1A and P1B as outputs.

FIGURE 18-4: HALF-BRIDGE PWM

OUTPUT

FIGURE 18-5: EXAMPLES OF HALF-BRIDGE OUTPUT MODE APPLICATIONS

Period

Duty Cycle

(1)

P1A(2)

P1B(2)

td = Dead Band Delay

Period

(1) (1)

Note 1: At this time, the TMR2 register is equal to the

PR2 register.

2: Output signals are shown as active-high.

PIC18F87J50

P1A

P1B

FET

Driver

FET

Driver

V+

V-

Load

FET

Driver

FET

Driver

V+

V-

Load

FET

Driver

FET

Driver

PIC18F87J50

P1A

P1B

Standard Half-Bridge Circuit (“Push-Pull”)

Half-Bridge Output Driving a Full-Bridge Circuit

PIC18F87J50 FAMILY

18.4.5 FULL-BRIDGE MODE

In Full-Bridge Output mode, four pins are used as

outputs; however, only two outputs are active at a time.

In the Forward mode, pin P1A is continuously active

and pin P1D is modulated. In the Reverse mode, pin

P1C is continuously active and pin P1B is modulated.

These are illustrated in Figure 18-6.

P1A, P1B, P1C and P1D outputs are multiplexed with

the port pins as described in Table 18-1, Table 18-2

and Table 18-3. The corresponding TRIS bits must be

cleared to make the P1A, P1B, P1C and P1D pins

outputs.

FIGURE 18-6: FULL-BRIDGE PWM OUTPUT

Period

Duty Cycle

P1A(2)

P1B(2)

P1C(2)

P1D(2)

Forward Mode

(1)

Period

Duty Cycle

P1A(2)

P1C(2)

P1D(2)

P1B(2)

Reverse Mode

(1)

Note 1: At this time, the TMR2 register is equal to the PR2 register.

Note 2: Output signal is shown as active-high.

PIC18F87J50 FAMILY

FIGURE 18-7: EXAMPLE OF FULL-BRIDGE OUTPUT APPLICATION

18.4.5.1 Direction Change in Full-Bridge

Output Mode

In the Full-Bridge Output mode, the P1M1 bit in the

CCP1CON register allows users to control the forward/

reverse direction. When the application firmware

changes this direction control bit, the module will

assume the new direction on the next PWM cycle.

Just before the end of the current PWM period, the

modulated outputs (P1B and P1D) are placed in their

inactive state, while the unmodulated outputs (P1A and

P1C) are switched to drive in the opposite direction.

This occurs in a time interval of (4 TOSC * (Timer2

Prescale Value) before the next PWM period begins.

The Timer2 prescaler will be either 1, 4 or 16, depend-

ing on the value of the T2CKPS bits (T2CON<1:0>).

During the interval from the switch of the unmodulated

outputs to the beginning of the next period, the

modulated outputs (P1B and P1D) remain inactive.

This relationship is shown in Figure 18-8.

Note that in the Full-Bridge Output mode, the ECCP1

module does not provide any dead-band delay. In gen-

eral, since only one output is modulated at all times,

dead-band delay is not required. However, there is a

situation where a dead-band delay might be required.

This situation occurs when both of the following

conditions are true:

1. The direction of the PWM output changes when

the duty cycle of the output is at or near 100%.

2. The turn-off time of the power switch, including

the power device and driver circuit, is greater

than the turn-on time.

Figure 18-9 shows an example where the PWM direc-

tion changes from forward to reverse at a near 100%

duty cycle. At time t1, the outputs, P1A and P1D,

become inactive, while output, P1C, becomes active. In

this example, since the turn-off time of the power

devices is longer than the turn-on time, a shoot-through

current may flow through power devices, QC and QD

(see Figure 18-7), for the duration of ‘t’. The same

phenomenon will occur to power devices, QA and QB,

for PWM direction change from reverse to forward.

If changing PWM direction at high duty cycle is required

for an application, one of the following requirements

must be met:

1. Reduce PWM for a PWM period before

changing directions.

2. Use switch drivers that can drive the switches off

faster than they can drive them on.

Other options to prevent shoot-through current may

exist.

PIC18F87J50

P1A

P1C

FET

Driver

FET

Driver

V+

V-

Load

FET

Driver

FET

Driver

P1B

P1D

QB QD

PIC18F87J50 FAMILY

FIGURE 18-8: PWM DIRECTION CHANGE

FIGURE 18-9: PWM DIRECTION CHANGE AT NEAR 100% DUTY CYCLE

Period(1)

SIGNAL

Note 1: The direction bit in the ECCP1 Control register (CCP1CON<7>) is written at any time during the PWM cycle.

2: When changing directions, the P1A and P1C signals switch before the end of the current PWM cycle at intervals

of 4 TOSC, 16 TOSC or 64 TOSC, depending on the Timer2 prescaler value. The modulated P1B and P1D signals

are inactive at this time.

Period

(Note 2)

P1A (Active-High)

P1B (Active-High)

P1C (Active-High)

P1D (Active-High)

Forward Period Reverse Period

P1A(1)

tON(2)

tOFF(3)

t = tOFF – tON(2,3)

P1B(1)

P1C(1)

P1D(1)

External Switch D(1)

Potential

Shoot-Through

Current(1)

Note 1: All signals are shown as active-high.

2: tON is the turn-on delay of power switch QC and its driver.

3: tOFF is the turn-off delay of power switch QD and its driver.

External Switch C(1)

PIC18F87J50 FAMILY

18.4.6 PROGRAMMABLE DEAD-BAND

DELAY

In half-bridge applications, where all power switches

are modulated at the PWM frequency at all times, the

power switches normally require more time to turn off

than to turn on. If both the upper and lower power

switches are switched at the same time (one turned on

and the other turned off), both switches may be on for

a short period of time until one switch completely turns

off. During this brief interval, a very high current

(shoot-through current) may flow through both power

switches, shorting the bridge supply. To avoid this

potentially destructive shoot-through current from flow-

ing during switching, turning on either of the power

switches is normally delayed to allow the other switch

to completely turn off.

In the Half-Bridge Output mode, a digitally program-

mable, dead-band delay is available to avoid

shoot-through current from destroying the bridge

power switches. The delay occurs at the signal

transition from the non-active state to the active state

(see Figure 18-4 for illustration). The lower seven bits of

the ECCP1DEL register (Register 18-2) set the delay

period in terms of microcontroller instruction cycles

CY or 4 TOSC).

18.4.7 ENHANCED PWM

AUTO-SHUTDOWN

When the ECCP1 is programmed for any of the

Enhanced PWM modes, the active output pins may be

configured for auto-shutdown. Auto-shutdown immedi-

ately places the Enhanced PWM output pins into a

defined shutdown state when a shutdown event

occurs.

A shutdown event can be caused by either of the two

comparator modules or the FLT0 pin (or any combina-

tion of these three sources). The comparators may be

used to monitor a voltage input proportional to a current

being monitored in the bridge circuit. If the voltage

exceeds a threshold, the comparator switches state and

triggers a shutdown. Alternatively, a low-level digital sig-

nal on the FLT0 pin can also trigger a shutdown. The

auto-shutdown feature can be disabled by not selecting

any auto-shutdown sources. The auto-shutdown

sources to be used are selected using the

ECCP1AS2:ECCP1AS0 bits (ECCP1AS<6:4>).

When a shutdown occurs, the output pins are

asynchronously placed in their shutdown states,

specified by the PSS1AC1:PSS1AC0 and

PSS1BD1:PSS1BD0 bits (ECCP1AS3:ECCP1AS0).

Each pin pair (P1A/P1C and P1B/P1D) may be set to

drive high, drive low or be tri-stated (not driving). The

ECCP1ASE bit (ECCP1AS<7>) is also set to hold the

Enhanced PWM outputs in their shutdown states.

The ECCP1ASE bit is set by hardware when a

shutdown event occurs. If automatic restarts are not

enabled, the ECCP1ASE bit is cleared by firmware

when the cause of the shutdown clears. If automatic

restarts are enabled, the ECCP1ASE bit is automati-

cally cleared when the cause of the auto-shutdown has

cleared.

If the ECCP1ASE bit is set when a PWM period begins,

the PWM outputs remain in their shutdown state for that

entire PWM period. When the ECCP1ASE bit is

cleared, the PWM outputs will return to normal

operation at the beginning of the next PWM period.

Note: Writing to the ECCP1ASE bit is disabled

while a shutdown condition is active.

R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

PxRSEN PxDC6 PxDC5 PxDC4 PxDC3 PxDC2 PxDC1 PxDC0

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 PxRSEN: PWM Restart Enable bit

1 = Upon auto-shutdown, the ECCPxASE bit clears automatically once the shutdown event goes

away; the PWM restarts automatically

0 = Upon auto-shutdown, ECCPxASE must be cleared in software to restart the PWM

bit 6-0 PxDC6:PxDC0: PWM Delay Count bits

Delay time, in number of FOSC/4 (4 * TOSC) cycles, between the scheduled and actual time for a PWM

signal to transition to active.

PIC18F87J50 FAMILY

18.4.7.1 Auto-Shutdown and Automatic

Restart

The auto-shutdown feature can be configured to allow

automatic restarts of the module following a shutdown

event. This is enabled by setting the P1RSEN bit of the

ECCP1DEL register (ECCP1DEL<7>).

In Shutdown mode with P1RSEN = 1 (Figure 18-10),

the ECCP1ASE bit will remain set for as long as the

cause of the shutdown continues. When the shutdown

condition clears, the ECCP1ASE bit is cleared. If

P1RSEN = 0 (Figure 18-11), once a shutdown condi-

tion occurs, the ECCP1ASE bit will remain set until it is

cleared by firmware. Once ECCP1ASE is cleared, the

Enhanced PWM will resume at the beginning of the

next PWM period.

Independent of the P1RSEN bit setting, if the

auto-shutdown source is one of the comparators, the

shutdown condition is a level. The ECCP1ASE bit

cannot be cleared as long as the cause of the shutdown

persists.

The Auto-Shutdown mode can be forced by writing a ‘1’

to the ECCP1ASE bit.

18.4.8 START-UP CONSIDERATIONS

When the ECCP1 module is used in the PWM mode,

the application hardware must use the proper external

pull-up and/or pull-down resistors on the PWM output

pins. When the microcontroller is released from Reset,

all of the I/O pins are in the high-impedance state. The

external circuits must keep the power switch devices in

the OFF state until the microcontroller drives the I/O

pins with the proper signal levels, or activates the PWM

output(s).

R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

ECCPxASE ECCPxAS2 ECCPxAS1 ECCPxAS0 PSSxAC1 PSSxAC0 PSSxBD1 PSSxBD0

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 ECCPxASE: ECCPx Auto-Shutdown Event Status bit

0 = ECCPx outputs are operating

1 = A shutdown event has occurred; ECCPx outputs are in shutdown state

bit 6-4 ECCPxAS2:ECCPxAS0: ECCPx Auto-Shutdown Source Select bits

000 = Auto-shutdown is disabled

001 = Comparator 1 output

010 = Comparator 2 output

011 = Either Comparator 1 or 2

100 =FLT0

101 = FLT0 or Comparator 1

110 = FLT0 or Comparator 2

111 = FLT0 or Comparator 1 or Comparator 2

bit 3-2 PSSxAC1:PSSxAC0: Pins A and C Shutdown State Control bits

00 = Drive Pins A and C to ‘0’

01 = Drive Pins A and C to ‘1’

1x = Pins A and C tri-state

bit 1-0 PSSxBD1:PSSxBD0: Pins B and D Shutdown State Control bits

00 = Drive Pins B and D to ‘0’

01 = Drive Pins B and D to ‘1’

1x = Pins B and D tri-state

Note: Writing to the ECCP1ASE bit is disabled

while a shutdown condition is active.

PIC18F87J50 FAMILY

The CCP1M1:CCP1M0 bits (CCP1CON<1:0>) allow

the user to choose whether the PWM output signals are

active-high or active-low for each pair of PWM output

pins (P1A/P1C and P1B/P1D). The PWM output

polarities must be selected before the PWM pins are

configured as outputs. Changing the polarity configura-

tion while the PWM pins are configured as outputs is

not recommended since it may result in damage to the

application circuits.

The P1A, P1B, P1C and P1D output latches may not be

in the proper states when the PWM module is initialized.

Enabling the PWM pins for output at the same time as

the ECCP1 module may cause damage to the applica-

tion circuit. The ECCP1 module must be enabled in the

proper output mode and complete a full PWM cycle

before configuring the PWM pins as outputs. The

completion of a full PWM cycle is indicated by the

TMR2IF bit being set as the second PWM period

begins.

FIGURE 18-10: PWM AUTO-SHUTDOWN (P1RSEN = 1, AUTO-RESTART ENABLED)

FIGURE 18-11: PWM AUTO-SHUTDOWN (P1RSEN = 0, AUTO-RESTART DISABLED)

Shutdown

PWM

ECCP1ASE bit

Activity

Event

Shutdown

Event Occurs

Shutdown

Event Clears

PWM

Resumes

Normal PWM

Start of

PWM Period

Shutdown

PWM

ECCP1ASE bit

Activity

Event

Shutdown

Event Occurs

Shutdown

Event Clears

PWM

Resumes

Normal PWM

Start of

PWM Period

ECCP1ASE

Cleared by

Firmware

PWM Period

PIC18F87J50 FAMILY

18.4.9 SETUP FOR PWM OPERATION

The following steps should be taken when configuring

the ECCPx module for PWM operation:

1. Configure the PWM pins PxA and PxB (and PxC

and PxD, if used) as inputs by setting the

corresponding TRIS bits.

2. Set the PWM period by loading the PR2 (PR4)

3. Configure the ECCPx module for the desired

PWM mode and configuration by loading the

CCPxCON register with the appropriate values:

• Select one of the available output

configurations and direction with the

PxM1:PxM0 bits.

• Select the polarities of the PWM output

signals with the CCPxM3:CCPxM0 bits.

4. Set the PWM duty cycle by loading the CCPRxL

5. For auto-shutdown:

• Disable auto-shutdown; ECCPxASE = 0

• Configure auto-shutdown source

• Wait for Run condition

6. For Half-Bridge Output mode, set the

dead-band delay by loading ECCPxDEL<6:0>

with the appropriate value.

7. If auto-shutdown operation is required, load the

ECCPxAS register:

• Select the auto-shutdown sources using the

ECCPxAS2:ECCPxAS0 bits.

• Select the shutdown states of the PWM

output pins using the PSSxAC1:PSSxAC0

and PSSxBD1:PSSxBD0 bits.

• Set the ECCPxASE bit (ECCPxAS<7>).

8. If auto-restart operation is required, set the

PxRSEN bit (ECCPxDEL<7>).

9. Configure and start TMRn (TMR2 or TMR4):

• Clear the TMRn interrupt flag bit by clearing

the TMRnIF bit (PIR1<1> for Timer2 or

PIR3<3> for Timer4).

• Set the TMRn prescale value by loading the

TnCKPS bits (TnCON<1:0>).

• Enable Timer2 (or Timer4) by setting the

TMRnON bit (TnCON<2>).

10. Enable PWM outputs after a new PWM cycle

has started:

• Wait until TMRn overflows (TMRnIF bit is set).

• Enable the ECCPx/PxA, PxB, PxC and/or

PxD pin outputs by clearing the respective

TRIS bits.

• Clear the ECCPxASE bit (ECCPxAS<7>).

18.4.10 EFFECTS OF A RESET

Both Power-on Reset and subsequent Resets will force

all ports to Input mode and the ECCP registers to their

Reset states.

This forces the Enhanced CCP module to reset to a

state compatible with the standard CCP module.

PIC18F87J50 FAMILY

TABLE 18-5: REGISTERS ASSOCIATED WITH ECCP MODULES AND TIMER1 TO TIMER4

Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Reset

Values

on Page:

INTCON GIE/GIEH PEIE/GIEL TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 61

RCON IPEN —CM RI TO PD POR BOR 62

PIR1 PMPIF ADIF RC1IF TX1IF SSP1IF CCP1IF TMR2IF TMR1IF 64

PIE1 PMPIE ADIE RC1IE TX1IE SSP1IE CCP1IE TMR2IE TMR1IE 64

IPR1 PMPIP ADIP RC1IP TX1IP SSP1IP CCP1IP TMR2IP TMR1IP 64

PIR2 OSCFIF CM2IF CM1IF USBIF BCL1IF LVDIF TMR3IF CCP2IF 64

PIE2 OSCFIE CM2IE CM1IE USBIE BCL1IE LVDIE TMR3IE CCP2IE 64

IPR2 OSCFIP CM2IP CM1IP USBIP BCL1IP LVDIP TMR3IP CCP2IP 64

PIR3 SSP2IF BCL2IF RC2IF TX2IF TMR4IF CCP5IF CCP4IF CCP3IF 64

PIE3 SSP2IE BCL2IE RC2IE TX2IE TMR4IE CCP5IE CCP4IE CCP3IE 64

IPR3 SSP2IP BCL2IP RC2IP TX2IP TMR4IP CCP5IP CCP4IP CCP3IP 64

TRISB TRISB7 TRISB6 TRISB5 TRISB4 TRISB3 TRISB2 TRISB1 TRISB0 64

TRISC TRISC7 TRISC6 TRISC5 TRISC4 TRISC3 TRISC2 TRISC1 TRISC0 64

TRISE TRISE7 TRISE6 TRISE5 TRISE4 TRISE3 TRISE2 TRISE1 TRISE0 64

TRISG — — — TRISG4 TRISG3 TRISG2 TRISG1 TRISG0 64

TRISH(1) TRISH7 TRISH6 TRISH5 TRISH4 TRISH3 TRISH2 TRISH1 TRISH0 64

TMR1L(3) Timer1 Register Low Byte 62

TMR1H(3) Timer1 Register High Byte 62

T1CON(3) RD16 T1RUN T1CKPS1 T1CKPS0 T1OSCEN T1SYNC TMR1CS TMR1ON 62

TMR2(3) Timer2 Register 62

T2CON — T2OUTPS3 T2OUTPS2 T2OUTPS1 T2OUTPS0 TMR2ON T2CKPS1 T2CKPS0 62

PR2(3) Timer2 Period Register 62

TMR3L Timer3 Register Low Byte 65

TMR3H Timer3 Register High Byte 65

T3CON RD16 T3CCP2 T3CKPS1 T3CKPS0 T3CCP1 T3SYNC TMR3CS TMR3ON 65

TMR4 Timer4 Register 65

T4CON — T4OUTPS3 T4OUTPS2 T4OUTPS1 T4OUTPS0 TMR4ON T4CKPS1 T4CKPS0 65

PR4(3) Timer4 Period Register 65

CCPRxL(2) Capture/Compare/PWM Register x Low Byte 63

CCPRxH(2) Capture/Compare/PWM Register x High Byte 63,

CCPxCON(2) PxM1 PxM0 DCxB1 DCxB0 CCPxM3 CCPxM2 CCPxM1 CCPxM0 63

ECCPxAS(2) ECCPxASE ECCPxAS2 ECCPxAS1 ECCPxAS0 PSSxAC1 PSSxAC0 PSSxBD1 PSSxBD0 63, 63, 63

ECCPxDEL(2) PxRSEN PxDC6 PxDC5 PxDC4 PxDC3 PxDC2 PxDC1 PxDC0 63, 63, 63

Legend: — = unimplemented, read as ‘0’. Shaded cells are not used during ECCP operation.

Note 1: Available on 80-pin devices only.

2: Generic term for all of the identical registers of this name for all Enhanced CCP modules, where ‘x’ identifies the

individual module (ECCP1, ECCP2 or ECCP3). Bit assignments and Reset values for all registers of the same

generic name are identical.

3: Default (legacy) SFR at this address, available when WDTCON<4> = 0.

PIC18F87J50 FAMILY

19.0 MASTER SYNCHRONOUS

SERIAL PORT (MSSP)

MODULE

19.1 Master SSP (MSSP) Module

Overview

The Master Synchronous Serial Port (MSSP) module is

a serial interface, useful for communicating with other

peripheral or microcontroller devices. These peripheral

devices may be serial EEPROMs, shift registers,

display drivers, A/D Converters, etc. The MSSP

module can operate in one of two modes:

• Serial Peripheral Interface (SPI)

• Inter-Integrated Circuit (I2C™)

- Full Master mode

- Slave mode (with general address call)

The I2C interface supports the following modes in

hardware:

•Master mode

• Multi-Master mode

• Slave mode with 5-bit and 7-bit address masking

(with address masking for both 10-bit and 7-bit

addressing)

All members of the PIC18F87J10 family have two

MSSP modules, designated as MSSP1 and MSSP2.

Each module operates independently of the other.

19.2 Control Registers

Each MSSP module has three associated control regis-

ters. These include a status register (SSPxSTAT) and

two control registers (SSPxCON1 and SSPxCON2). The

use of these registers and their individual configuration

bits differ significantly depending on whether the MSSP

module is operated in SPI or I2C mode.

Additional details are provided under the individual

sections.

19.3 SPI Mode

The SPI mode allows 8 bits of data to be synchronously

transmitted and received simultaneously. All four

modes of SPI are supported. To accomplish

communication, typically three pins are used:

• Serial Data Out (SDOx) – RC5/SDO1 or

RD4/SDO2

• Serial Data In (SDIx) – RC4/SDI1/SDA1 or

RD5/SDI2/SDA2

• Serial Clock (SCKx) – RC3/SCK1/SCL1 or

RD6/SCK2/SCL2

Additionally, a fourth pin may be used when in a Slave

mode of operation:

• Slave Select (SSx) – RF7/SS1 or RD7/SS2

Figure 19-1 shows the block diagram of the MSSP

module when operating in SPI mode.

FIGURE 19-1: MSSPx BLOCK DIAGRAM

(SPI MODE)

Note: Throughout this section, generic refer-

ences to an MSSP module in any of its

operating modes may be interpreted as

being equally applicable to MSSP1 or

MSSP2. Register names and module I/O

signals use the generic designator ‘x’ to

indicate the use of a numeral to distinguish

a particular module when required. Control

bit names are not individuated.

Note: In devices with more than one MSSP

module, it is very important to pay close

attention to SSPxCON register names.

SSP1CON1 and SSP1CON2 control

different operational aspects of the same

module, while SSP1CON1 and

SSP2CON1 control the same features for

two different modules.

( )

Read Write

Internal

Data Bus

SSPxSR reg

SSPM3:SSPM0

bit 0 Shift

Clock

SSxControl

Enable

Edge

Select

Clock Select

TMR2 Output

TOSC

Prescaler

4, 16, 64

Edge

Select

Data to TXx/RXx in SSPxSR

TRIS bit

SMP:CKE

SDOx

SSPxBUF reg

SDIx

SSx

SCKx

Note: Only port I/O names are used in this diagram for

the sake of brevity. Refer to the text for a full list of

multiplexed functions.

PIC18F87J50 FAMILY

19.3.1 REGISTERS

Each MSSP module has four registers for SPI mode

operation. These are:

• MSSPx Control Register 1 (SSPxCON1)

• MSSPx Status Register (SSPxSTAT)

• Serial Receive/Transmit Buffer Register

(SSPxBUF)

• MSSPx Shift Register (SSPxSR) – Not directly

accessible

SSPxCON1 and SSPxSTAT are the control and status

registers in SPI mode operation. The SSPxCON1

the SSPxSTAT are read-only. The upper two bits of the

SSPxSTAT are read/write.

SSPxSR is the shift register used for shifting data in or

out. SSPxBUF is the buffer register to which data

bytes are written to or read from.

In receive operations, SSPxSR and SSPxBUF

together create a double-buffered receiver. When

SSPxSR receives a complete byte, it is transferred to

SSPxBUF and the SSPxIF interrupt is set.

During transmission, the SSPxBUF is not

double-buffered. A write to SSPxBUF will write to both

SSPxBUF and SSPxSR.

R/W-0 R/W-0 R-0 R-0 R-0 R-0 R-0 R-0

SMP CKE(1) D/A PSR/WUA BF

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 SMP: Sample bit

SPI Master mode:

1 = Input data sampled at end of data output time

0 = Input data sampled at middle of data output time

SPI Slave mode:

SMP must be cleared when SPI is used in Slave mode.

bit 6 CKE: SPI Clock Select bit(1)

1 = Transmit occurs on transition from active to Idle clock state

0 = Transmit occurs on transition from Idle to active clock state

bit 5 D/A: Data/Address bit

Used in I2C mode only.

bit 4 P: Stop bit

Used in I2C mode only. This bit is cleared when the MSSP module is disabled, SSPEN is cleared.

bit 3 S: Start bit

Used in I2C mode only.

bit 2 R/W: Read/Write Information bit

Used in I2C mode only.

bit 1 UA: Update Address bit

Used in I2C mode only.

bit 0 BF: Buffer Full Status bit (Receive mode only)

1 = Receive complete, SSPxBUF is full

0 = Receive not complete, SSPxBUF is empty

Note 1: Polarity of clock state is set by the CKP bit (SSPxCON1<4>).

PIC18F87J50 FAMILY

R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

WCOL SSPOV(1) SSPEN(2) CKP SSPM3(3) SSPM2(3) SSPM1(3) SSPM0(3)

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 WCOL: Write Collision Detect bit

1 = The SSPxBUF register is written while it is still transmitting the previous word (must be cleared in

software)

0 = No collision

bit 6 SSPOV: Receive Overflow Indicator bit(1)

SPI Slave mode:

1 = A new byte is received while the SSPxBUF register is still holding the previous data. In case of over-

flow, the data in SSPxSR is lost. Overflow can only occur in Slave mode. The user must read the

SSPxBUF, even if only transmitting data, to avoid setting overflow (must be cleared in software).

0 = No overflow

bit 5 SSPEN: Master Synchronous Serial Port Enable bit(2)

1 = Enables serial port and configures SCKx, SDOx, SDIx and SSx as serial port pins

0 = Disables serial port and configures these pins as I/O port pins

bit 4 CKP: Clock Polarity Select bit

1 = Idle state for clock is a high level

0 = Idle state for clock is a low level

bit 3-0 SSPM3:SSPM0: Master Synchronous Serial Port Mode Select bits(3)

0101 = SPI Slave mode, clock = SCKx pin, SSx pin control disabled, SSx can be used as I/O pin

0100 = SPI Slave mode, clock = SCKx pin, SSx pin control enabled

0011 = SPI Master mode, clock = TMR2 output/2

0010 = SPI Master mode, clock = FOSC/64

0001 = SPI Master mode, clock = FOSC/16

0000 = SPI Master mode, clock = FOSC/4

Note 1: In Master mode, the overflow bit is not set since each new reception (and transmission) is initiated by

writing to the SSPxBUF register.

2: When enabled, this pin must be properly configured as input or output.

3: Bit combinations not specifically listed here are either reserved or implemented in I2C™ mode only.

PIC18F87J50 FAMILY

19.3.2 OPERATION

When initializing the SPI, several options need to be

specified. This is done by programming the appropriate

control bits (SSPxCON1<5:0> and SSPxSTAT<7:6>).

These control bits allow the following to be specified:

• Master mode (SCKx is the clock output)

• Slave mode (SCKx is the clock input)

• Clock Polarity (Idle state of SCKx)

• Data Input Sample Phase (middle or end of data

output time)

• Clock Edge (output data on rising/falling edge of

SCKx)

• Clock Rate (Master mode only)

• Slave Select mode (Slave mode only)

Each MSSP module consists of a transmit/receive shift

The SSPxSR shifts the data in and out of the device,

MSb first. The SSPxBUF holds the data that was written

to the SSPxSR until the received data is ready. Once the

8 bits of data have been received, that byte is moved to

the SSPxBUF register. Then, the Buffer Full detect bit,

BF (SSPxSTAT<0>) and the interrupt flag bit, SSPxIF,

are set. This double-buffering of the received data

(SSPxBUF) allows the next byte to start reception before

reading the data that was just received. Any write to the

SSPxBUF register during transmission/reception of data

will be ignored and the Write Collision Detect bit, WCOL

(SSPxCON1<7>), will be set. User software must clear

the WCOL bit so that it can be determined if the following

write(s) to the SSPxBUF register completed

successfully.

When the application software is expecting to receive

valid data, the SSPxBUF should be read before the next

byte of data to transfer is written to the SSPxBUF. The

Buffer Full bit, BF (SSPxSTAT<0>), indicates when

SSPxBUF has been loaded with the received data

(transmission is complete). When the SSPxBUF is read,

the BF bit is cleared. This data may be irrelevant if the

SPI is only a transmitter. Generally, the MSSP interrupt

is used to determine when the transmission/reception

has completed. If the interrupt method is not going to be

used, then software polling can be done to ensure that a

write collision does not occur. Example 19-1 shows the

loading of the SSPxBUF (SSPxSR) for data

transmission.

The SSPxSR is not directly readable or writable and

can only be accessed by addressing the SSPxBUF

the various status conditions.

19.3.3 OPEN-DRAIN OUTPUT OPTION

The drivers for the SDOx output and SCKx clock pins

can be optionally configured as open-drain outputs.

This feature allows the voltage level on the pin to be

pulled to a higher level through an external pull-up

resistor, and allows the output to communicate with

external circuits without the need for additional level

shifters. For more information, see Section 10.1.4

“Open-Drain Outputs”.

The open-drain output option is controlled by the

SPI2OD and SPI1OD bits (ODCON3<1:0>. Setting an

SPIxOD bit configures both SDO and SCK pins for the

corresponding open-drain operation.

The ODCON3 register shares the same address as the

T1CON register. The ODCON3 register is accessed by

setting the ADSHR bit in the WDTCON register

(WDTCON<4>).

EXAMPLE 19-1: LOADING THE SSP1BUF (SSP1SR) REGISTER

LOOP BTFSS SSP1STAT, BF ;Has data been received (transmit complete)?

BRA LOOP ;No

MOVF SSP1BUF, W ;WREG reg = contents of SSP1BUF

MOVWF RXDATA ;Save in user RAM, if data is meaningful

MOVF TXDATA, W ;W reg = contents of TXDATA

MOVWF SSP1BUF ;New data to xmit

PIC18F87J50 FAMILY

19.3.4 ENABLING SPI I/O

To enable the serial port, MSSP Enable bit, SSPEN

(SSPxCON1<5>), must be set. To reset or reconfigure

SPI mode, clear the SSPEN bit, reinitialize the

SSPxCON registers and then set the SSPEN bit. This

configures the SDIx, SDOx, SCKx and SSx pins as

serial port pins. For the pins to behave as the serial port

function, some must have their data direction bits (in

the TRIS register) appropriately programmed as

follows:

• SDIx is automatically controlled by the

SPI module

• SDOx must have the TRISC<5> or TRISD<4> bit

cleared

• SCKx (Master mode) must have the TRISC<3> or

TRISD<6>bit cleared

• SCKx (Slave mode) must have the TRISC<3> or

TRISD<6> bit set

• SSx must have the TRISF<7> or TRISD<7> bit

set

Any serial port function that is not desired may be

overridden by programming the corresponding Data

Direction (TRIS) register to the opposite value.

19.3.5 TYPICAL CONNECTION

Figure 19-2 shows a typical connection between two

microcontrollers. The master controller (Processor 1)

initiates the data transfer by sending the SCKx signal.

Data is shifted out of both shift registers on their pro-

grammed clock edge and latched on the opposite edge

of the clock. Both processors should be programmed to

the same Clock Polarity (CKP), then both controllers

would send and receive data at the same time.

Whether the data is meaningful (or dummy data)

depends on the application software. This leads to

three scenarios for data transmission:

• Master sends data – Slave sends dummy data

• Master sends data – Slave sends data

• Master sends dummy data – Slave sends data

FIGURE 19-2: SPI MASTER/SLAVE CONNECTION

Serial Input Buffer

(SSPxBUF)

Shift Register

(SSPxSR)

MSb LSb

SDOx

SDIx

PROCESSOR 1

SCKx

SPI Master SSPM3:SSPM0 = 00xxb

Serial Input Buffer

(SSPxBUF)

Shift Register

(SSPxSR)

LSb

MSb

SDIx

SDOx

PROCESSOR 2

SCKx

SPI Slave SSPM3:SSPM0 = 010xb

Serial Clock

PIC18F87J50 FAMILY

19.3.6 MASTER MODE

The master can initiate the data transfer at any time

because it controls the SCKx. The master determines

when the slave (Processor 1, Figure 19-2) is to

broadcast data by the software protocol.

In Master mode, the data is transmitted/received as

soon as the SSPxBUF register is written to. If the SPI

is only going to receive, the SDOx output could be dis-

abled (programmed as an input). The SSPxSR register

will continue to shift in the signal present on the SDIx

pin at the programmed clock rate. As each byte is

received, it will be loaded into the SSPxBUF register as

if a normal received byte (interrupts and status bits

appropriately set). This could be useful in receiver

applications as a “Line Activity Monitor” mode.

The clock polarity is selected by appropriately

programming the CKP bit (SSPxCON1<4>). This then,

would give waveforms for SPI communication as

shown in Figure 19-3, Figure 19-5 and Figure 19-6,

where the MSB is transmitted first. In Master mode, the

SPI clock rate (bit rate) is user programmable to be one

of the following:

•F

OSC/4 (or TCY)

•FOSC/16 (or 4 • TCY)

•F

OSC/64 (or 16 • TCY)

• Timer2 output/2

This allows a maximum data rate (at 40 MHz) of

10.00 Mbps.

Figure 19-3 shows the waveforms for Master mode.

When the CKE bit is set, the SDOx data is valid before

there is a clock edge on SCKx. The change of the input

sample is shown based on the state of the SMP bit. The

time when the SSPxBUF is loaded with the received

data is shown.

FIGURE 19-3: SPI MODE WAVEFORM (MASTER MODE)

SCKx

(CKP = 0

SCKx

(CKP = 1

SCKx

(CKP = 0

SCKx

(CKP = 1

4 Clock

Modes

Input

Sample

Input

Sample

SDIx

bit 7 bit 0

SDOx bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0

bit 7

SDIx

SSPxIF

(SMP = 1)

(SMP = 0)

(SMP = 1)

CKE = 1)

CKE = 0)

CKE = 1)

CKE = 0)

(SMP = 0)

Write to

SSPxBUF

SSPxSR to

SSPxBUF

SDOx bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0

(CKE = 0)

(CKE = 1)

Next Q4 Cycle

after Q2↓

bit 0

PIC18F87J50 FAMILY

19.3.7 SLAVE MODE

In Slave mode, the data is transmitted and received as

the external clock pulses appear on SCKx. When the

last bit is latched, the SSPxIF interrupt flag bit is set.

While in Slave mode, the external clock is supplied by

the external clock source on the SCKx pin. This exter-

nal clock must meet the minimum high and low times

as specified in the electrical specifications.

While in Sleep mode, the slave can transmit/receive

data. When a byte is received, the device can be

configured to wake-up from Sleep.

19.3.8 SLAVE SELECT

SYNCHRONIZATION

The SSx pin allows a Synchronous Slave mode. The

SPI must be in Slave mode with the SSx pin control

enabled (SSPxCON1<3:0> = 04h). When the SSx pin

is low, transmission and reception are enabled and the

SDOx pin is driven. When the SSx pin goes high, the

SDOx pin is no longer driven, even if in the middle of a

transmitted byte and becomes a floating output. Exter-

nal pull-up/pull-down resistors may be desirable

depending on the application.

When the SPI module resets, the bit counter is forced

to ‘0’. This can be done by either forcing the SSx pin to

a high level or clearing the SSPEN bit.

To emulate two-wire communication, the SDOx pin can

be connected to the SDIx pin. When the SPI needs to

operate as a receiver, the SDOx pin can be configured

as an input. This disables transmissions from the

SDOx. The SDIx can always be left as an input (SDIx

function) since it cannot create a bus conflict.

FIGURE 19-4: SLAVE SYNCHRONIZATION WAVEFORM

Note 1: When the SPI is in Slave mode

with SSx pin control enabled

(SSPxCON1<3:0> = 0100), the SPI

module will reset if the SSx pin is set to VDD.

2: If the SPI is used in Slave mode with CKE

set, then the SSx pin control must be

enabled.

SCKx

(CKP = 1

SCKx

(CKP = 0

Input

Sample

SDIx

bit 7

SDOx bit 7 bit 6 bit 7

SSPxIF

Interrupt

(SMP = 0)

CKE = 0)

(SMP = 0)

Write to

SSPxBUF

SSPxSR to

SSPxBUF

SSx

Flag

bit 0

bit 7

bit 0

Next Q4 Cycle

after Q2

↓

PIC18F87J50 FAMILY

FIGURE 19-5: SPI MODE WAVEFORM (SLAVE MODE WITH CKE = 0)

FIGURE 19-6: SPI MODE WAVEFORM (SLAVE MODE WITH CKE = 1)

SCKx

(CKP = 1

SCKx

(CKP = 0

Input

Sample

SDIx

bit 7

SDOx bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0

SSPxIF

Interrupt

(SMP = 0)

CKE = 0)

(SMP = 0)

Write to

SSPxBUF

SSPxSR to

SSPxBUF

SSx

Flag

Optional

Next Q4 Cycle

after Q2↓

bit 0

SCKx

(CKP = 1

SCKx

(CKP = 0

Input

Sample

SDIx

bit 7 bit 0

SDOx bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0

SSPxIF

Interrupt

(SMP = 0)

CKE = 1)

(SMP = 0)

Write to

SSPxBUF

SSPxSR to

SSPxBUF

SSx

Flag

Not Optional

Next Q4 Cycle

after Q2↓

PIC18F87J50 FAMILY

19.3.9 OPERATION IN POWER-MANAGED

MODES

In SPI Master mode, module clocks may be operating

at a different speed than when in full power mode; in

the case of the Sleep mode, all clocks are halted.

In Idle modes, a clock is provided to the peripherals.

That clock can be from the primary clock source, the

secondary clock (Timer1 oscillator) or the INTOSC

source. See Section 2.4 “Clock Sources and

Oscillator Switching” for additional information.

In most cases, the speed that the master clocks SPI

data is not important; however, this should be

evaluated for each system.

If MSSP interrupts are enabled, they can wake the con-

troller from Sleep mode, or one of the Idle modes, when

the master completes sending data. If an exit from

Sleep or Idle mode is not desired, MSSP interrupts

should be disabled.

If the Sleep mode is selected, all module clocks are

halted and the transmission/reception will remain in

that state until the device wakes. After the device

returns to Run mode, the module will resume

transmitting and receiving data.

In SPI Slave mode, the SPI Transmit/Receive Shift

allows the device to be placed in any power-managed

mode and data to be shifted into the SPI Trans-

mit/Receive Shift register. When all 8 bits have been

received, the MSSP interrupt flag bit will be set and if

enabled, will wake the device.

19.3.10 EFFECTS OF A RESET

A Reset disables the MSSP module and terminates the

current transfer.

19.3.11 BUS MODE COMPATIBILITY

Table 19-1 shows the compatibility between the

standard SPI modes and the states of the CKP and

CKE control bits.

TABLE 19-1: SPI BUS MODES

There is also an SMP bit which controls when the data

is sampled.

19.3.12 SPI CLOCK SPEED AND MODULE

INTERACTIONS

Because MSSP1 and MSSP2 are independent

modules, they can operate simultaneously at different

data rates. Setting the SSPM3:SSPM0 bits of the

SSPxCON1 register determines the rate for the

corresponding module.

An exception is when both modules use Timer2 as a

time base in Master mode. In this instance, any

changes to the Timer2 module’s operation will affect

both MSSP modules equally. If different bit rates are

required for each module, the user should select one of

the other three time base options for one of the

modules.

Standard SPI Mode

Terminology

Control Bits State

CKP CKE

0, 0 0 1

0, 1 0 0

1, 0 1 1

1, 1 1 0

PIC18F87J50 FAMILY

TABLE 19-2: REGISTERS ASSOCIATED WITH SPI OPERATION

Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Reset

Values

on Page:

INTCON GIE/GIEH PEIE/GIEL TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 61

PIR1 PMPIF ADIF RC1IF TX1IF SSP1IF CCP1IF TMR2IF TMR1IF 64

PIE1 PMPIE ADIE RC1IE TX1IE SSP1IE CCP1IE TMR2IE TMR1IE 64

IPR1 PMPIP ADIP RC1IP TX1IP SSP1IP CCP1IP TMR2IP TMR1IP 64

PIR3 SSP2IF BCL2IF RC2IF TX2IF TMR4IF CCP5IF CCP4IF CCP3IF 64

PIE3 SSP2IE BCL2IE RC2IE TX2IE TMR4IE CCP5IE CCP4IE CCP3IE 64

IPR3 SSP2IP BCL2IP RC2IP TX2IP TMR4IP CCP5IP CCP4IP CCP3IP 64

TRISC TRISC7 TRISC6 TRISC5 TRISC4 TRISC3 TRISC2 TRISC1 TRISC0 64

TRISD TRISD7 TRISD6 TRISD5 TRISD4 TRISD3 TRISD2 TRISD1 TRISD0 64

TRISF TRISF7 TRISF6 TRISF5 TRISF4 TRISF3 TRISF2 ——64

SSP1BUF MSSP1 Receive Buffer/Transmit Register 62

SSPxCON1 WCOL SSPOV SSPEN CKP SSPM3 SSPM2 SSPM1 SSPM0 62, 65

SSPxSTAT SMP CKE D/A P S R/W UA BF 62, 65

SSP2BUF MSSP2 Receive Buffer/Transmit Register 65

ODCON3(1) — — — — — —SPI2ODSPI1OD62

Legend: Shaded cells are not used by the MSSP module in SPI mode.

Note 1: Configuration SFR, overlaps with default SFR at this address; available only when WDTCON<4> = 1.

PIC18F87J50 FAMILY

19.4 I2C Mode

The MSSP module in I2C mode fully implements all

master and slave functions (including general call

support), and provides interrupts on Start and Stop bits

in hardware to determine a free bus (multi-master

function). The MSSP module implements the standard

mode specifications, as well as 7-bit and 10-bit

addressing.

Two pins are used for data transfer:

• Serial Clock (SCLx) – RC3/SCK1/SCL1 or

RD6/SCK2/SCL2

• Serial Data (SDAx) – RC4/SDI1/SDA1 or

RD5/SDI2/SDA2

The user must configure these pins as inputs by setting

the associated TRIS bits.

FIGURE 19-7: MSSPx BLOCK DIAGRAM

(I2C™ MODE)

19.4.1 REGISTERS

The MSSP module has six registers for I2C operation.

These are:

• MSSPx Control Register 1 (SSPxCON1)

• MSSPx Control Register 2 (SSPxCON2)

• MSSPx Status Register (SSPxSTAT)

• Serial Receive/Transmit Buffer Register

(SSPxBUF)

• MSSPx Shift Register (SSPxSR) – Not directly

accessible

• MSSPx Address Register (SSPxADD)

• MSSPx 7-Bit Address Mask Register (SSPxMSK)

SSPxCON1, SSPxCON2 and SSPxSTAT are the

control and status registers in I2C mode operation. The

SSPxCON1 and SSPxCON2 registers are readable and

writable. The lower 6 bits of the SSPxSTAT are

read-only. The upper two bits of the SSPxSTAT are

read/write.

SSPxSR is the shift register used for shifting data in or

out. SSPxBUF is the buffer register to which data

bytes are written to or read from.

SSPxADD contains the slave device address when the

MSSP is configured in I2C Slave mode. When the

MSSP is configured in Master mode, the lower seven

bits of SSPxADD act as the Baud Rate Generator

reload value.

SSPxMSK holds the slave address mask value when

the module is configured for 7-bit Address Masking

mode. While it is a separate register, it shares the same

SFR address as SSPxADD; it is only accessible when

the SSPM3:SSPM0 bits are specifically set to permit

access. Additional details are provided in

Section 19.4.3.4 “7-Bit Address Masking Mode”.

In receive operations, SSPxSR and SSPxBUF

together, create a double-buffered receiver. When

SSPxSR receives a complete byte, it is transferred to

SSPxBUF and the SSPxIF interrupt is set.

During transmission, the SSPxBUF is not

double-buffered. A write to SSPxBUF will write to both

SSPxBUF and SSPxSR.

Read Write

SSPxSR reg

Match Detect

SSPxADD reg

SSPxBUF reg

Internal

Data Bus

Addr Match

Set, Reset

S, P bits

(SSPxSTAT reg)

Shift

Clock

MSb LSb

Note: Only port I/O names are used in this diagram for

the sake of brevity. Refer to the text for a full list of

multiplexed functions.

SCLx

SDAx

Start and

Stop bit Detect

Address Mask

PIC18F87J50 FAMILY

R/W-0 R/W-0 R-0 R-0 R-0 R-0 R-0 R-0

SMP CKE D/A P(1) S(1) R/W(2,3) UA BF

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 SMP: Slew Rate Control bit

In Master or Slave mode:

1 = Slew rate control disabled for Standard Speed mode (100 kHz and 1 MHz)

0 = Slew rate control enabled for High-Speed mode (400 kHz)

bit 6 CKE: SMBus Select bit

In Master or Slave mode:

1 = Enable SMBus specific inputs

0 = Disable SMBus specific inputs

bit 5 D/A: Data/Address bit

In Master mode:

Reserved.

In Slave mode:

1 = Indicates that the last byte received or transmitted was data

0 = Indicates that the last byte received or transmitted was address

bit 4 P: Stop bit(1)

1 = Indicates that a Stop bit has been detected last

0 = Stop bit was not detected last

bit 3 S: Start bit(1)

1 = Indicates that a Start bit has been detected last

0 = Start bit was not detected last

bit 2 R/W: Read/Write Information bit(2,3)

In Slave mode:

1 = Read

0 = Write

In Master mode:

1 = Transmit is in progress

0 = Transmit is not in progress

bit 1 UA: Update Address bit (10-Bit Slave mode only)

1 = Indicates that the user needs to update the address in the SSPxADD register

0 = Address does not need to be updated

bit 0 BF: Buffer Full Status bit

In Transmit mode:

1 = SSPxBUF is full

0 = SSPxBUF is empty

In Receive mode:

1 = SSPxBUF is full (does not include the ACK and Stop bits)

0 = SSPxBUF is empty (does not include the ACK and Stop bits)

Note 1: This bit is cleared on Reset and when SSPEN is cleared.

2: This bit holds the R/W bit information following the last address match. This bit is only valid from the

address match to the next Start bit, Stop bit or not ACK bit.

3: ORing this bit with SEN, RSEN, PEN, RCEN or ACKEN will indicate if the MSSP is in Active mode.

PIC18F87J50 FAMILY

R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

WCOL SSPOV SSPEN(1) CKP SSPM3(2) SSPM2(2) SSPM1(2) SSPM0(2)

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 WCOL: Write Collision Detect bit

In Master Transmit mode:

1 = A write to the SSPxBUF register was attempted while the I2C conditions were not valid for a

transmission to be started (must be cleared in software)

0 = No collision

In Slave Transmit mode:

1 = The SSPxBUF register is written while it is still transmitting the previous word (must be cleared in

software)

0 = No collision

In Receive mode (Master or Slave modes):

This is a “don’t care” bit.

bit 6 SSPOV: Receive Overflow Indicator bit

In Receive mode:

1 = A byte is received while the SSPxBUF register is still holding the previous byte (must be cleared in

software)

0 = No overflow

In Transmit mode:

This is a “don’t care” bit in Transmit mode.

bit 5 SSPEN: Master Synchronous Serial Port Enable bit(1)

1 = Enables the serial port and configures the SDAx and SCLx pins as the serial port pins

0 = Disables serial port and configures these pins as I/O port pins

bit 4 CKP: SCKx Release Control bit

In Slave mode:

1 = Releases clock

0 = Holds clock low (clock stretch), used to ensure data setup time

In Master mode:

Unused in this mode.

bit 3-0 SSPM3:SSPM0: Master Synchronous Serial Port Mode Select bits(2)

1111 = I2C Slave mode, 10-bit address with Start and Stop bit interrupts enabled

1110 = I2C Slave mode, 7-bit address with Start and Stop bit interrupts enabled

1011 = I2C Firmware Controlled Master mode (Slave Idle)

1001 = Load SSPMSK register at SSPADD SFR address(3,4)

1000 = I2C Master mode, clock = FOSC/(4 * (SSPxADD + 1))

0111 = I2C Slave mode, 10-bit address

0110 = I2C Slave mode, 7-bit address

Note 1: When enabled, the SDAx and SCLx pins must be configured as inputs.

2: Bit combinations not specifically listed here are either reserved or implemented in SPI mode only.

3: When SSPM3:SSPM0 = 1001, any reads or writes to the SSPxADD SFR address actually accesses the

SSPMSK register.

4: This mode is only available when 7-bit Address Masking mode is selected (MSSPMSK Configuration bit is

‘1’).

PIC18F87J50 FAMILY

R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

GCEN ACKSTAT ACKDT(1) ACKEN(2) RCEN(2) PEN(2) RSEN(2) SEN(2)

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 GCEN: General Call Enable bit (Slave mode only)

1 = Enable interrupt when a general call address (0000h) is received in the SSPxSR

0 = General call address disabled

bit 6 ACKSTAT: Acknowledge Status bit (Master Transmit mode only)

1 = Acknowledge was not received from slave

0 = Acknowledge was received from slave

bit 5 ACKDT: Acknowledge Data bit (Master Receive mode only)(1)

1 = Not Acknowledge

0 = Acknowledge

bit 4 ACKEN: Acknowledge Sequence Enable bit(2)

1 = Initiates Acknowledge sequence on SDAx and SCLx pins and transmit ACKDT data bit.

Automatically cleared by hardware.

0 = Acknowledge sequence Idle

bit 3 RCEN: Receive Enable bit (Master Receive mode only)(2)

1 = Enables Receive mode for I2C

0 = Receive Idle

bit 2 PEN: Stop Condition Enable bit(2)

1 = Initiates Stop condition on SDAx and SCLx pins. Automatically cleared by hardware.

0 = Stop condition Idle

bit 1 RSEN: Repeated Start Condition Enable bit(2)

1 = Initiates Repeated Start condition on SDAx and SCLx pins. Automatically cleared by hardware.

0 = Repeated Start condition Idle

bit 0 SEN: Start Condition Enable bit(2)

1 = Initiates Start condition on SDAx and SCLx pins. Automatically cleared by hardware.

0 = Start condition Idle

Note 1: Value that will be transmitted when the user initiates an Acknowledge sequence at the end of a receive.

2: If the I2C module is active, these bits may not be set (no spooling) and the SSPxBUF may not be written

(or writes to the SSPxBUF are disabled).

PIC18F87J50 FAMILY

R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

GCEN ACKSTAT ADMSK5 ADMSK4 ADMSK3 ADMSK2 ADMSK1 SEN

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 GCEN: General Call Enable bit (Slave mode only)

1 = Enables interrupt when a general call address (0000h) is received in the SSPxSR

0 = General call address disabled

bit 6 ACKSTAT: Acknowledge Status bit

Unused in Slave mode.

bit 5-2 ADMSK5:ADMSK2: Slave Address Mask Select bits (5-Bit Address Masking)

1 = Masking of corresponding bits of SSPxADD enabled

0 = Masking of corresponding bits of SSPxADD disabled

bit 1 ADMSK1: Slave Address Least Significant bit(s) Mask Select bit

In 7-Bit Addressing mode:

1 = Masking of SSPxADD<1> only enabled

0 = Masking of SSPxADD<1> only disabled

In 10-Bit Addressing mode:

1 = Masking of SSPxADD<1:0> enabled

0 = Masking of SSPxADD<1:0> disabled

bit 0 SEN: Start Condition Enable/Stretch Enable bit(1)

1 = Clock stretching is enabled for both slave transmit and slave receive (stretch enabled)

0 = Clock stretching is disabled

Note 1: If the I2C module is active, these bits may not be set (no spooling) and the SSPxBUF may not be written

(or writes to the SSPxBUF are disabled).

R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1

MSK7 MSK6 MSK5 MSK4 MSK3 MSK2 MSK1 MSK0(2)

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7-0 MSK7:MSK0: Slave Address Mask Select bit

1 = Masking of corresponding bit of SSPxADD enabled

0 = Masking of corresponding bit of SSPxADD disabled

Note 1: This register shares the same SFR address as SSPxADD, and is only addressable in select MSSP

operating modes. See Section 19.4.3.4 “7-Bit Address Masking Mode” for more details.

2: MSK0 is not used as a mask bit in 7-bit addressing.

PIC18F87J50 FAMILY

19.4.2 OPERATION

The MSSP module functions are enabled by setting the

MSSP Enable bit, SSPEN (SSPxCON1<5>).

The SSPxCON1 register allows control of the I2C

operation. Four mode selection bits (SSPxCON1<3:0>)

allow one of the following I2C modes to be selected:

•I

2C Master mode, clock

•I

2C Slave mode (7-bit address)

•I

2C Slave mode (10-bit address)

•I

2C Slave mode (7-bit address) with Start and

Stop bit interrupts enabled

•I

2C Slave mode (10-bit address) with Start and

Stop bit interrupts enabled

•I

2C Firmware Controlled Master mode, slave is

Idle

Selection of any I2C mode with the SSPEN bit set

forces the SCLx and SDAx pins to be open-drain,

provided these pins are programmed as inputs by

setting the appropriate TRISC or TRISD bits. To ensure

proper operation of the module, pull-up resistors must

be provided externally to the SCLx and SDAx pins.

19.4.3 SLAVE MODE

In Slave mode, the SCLx and SDAx pins must be

configured as inputs (TRISC<4:3> set). The MSSP

module will override the input state with the output data

when required (slave-transmitter).

The I2C Slave mode hardware will always generate an

interrupt on an address match. Address masking will

allow the hardware to generate an interrupt for more

than one address (up to 31 in 7-bit addressing and up

to 63 in 10-bit addressing). Through the mode select

bits, the user can also choose to interrupt on Start and

Stop bits.

When an address is matched, or the data transfer after

an address match is received, the hardware auto-

matically will generate the Acknowledge (ACK) pulse

and load the SSPxBUF register with the received value

currently in the SSPxSR register.

Any combination of the following conditions will cause

the MSSP module not to give this ACK pulse:

• The Buffer Full bit, BF (SSPxSTAT<0>), was set

before the transfer was received.

• The overflow bit, SSPOV (SSPxCON1<6>), was

set before the transfer was received.

In this case, the SSPxSR register value is not loaded

into the SSPxBUF, but bit SSPxIF is set. The BF bit is

cleared by reading the SSPxBUF register, while bit

SSPOV is cleared through software.

The SCLx clock input must have a minimum high and

low for proper operation. The high and low times of the

I2C specification, as well as the requirement of the

MSSP module, are shown in timing parameter 100 and

parameter 101.

19.4.3.1 Addressing

Once the MSSP module has been enabled, it waits for

a Start condition to occur. Following the Start condition,

the 8 bits are shifted into the SSPxSR register. All

incoming bits are sampled with the rising edge of the

clock (SCLx) line. The value of register, SSPxSR<7:1>,

is compared to the value of the SSPxADD register. The

address is compared on the falling edge of the eighth

clock (SCLx) pulse. If the addresses match and the BF

and SSPOV bits are clear, the following events occur:

1. The SSPxSR register value is loaded into the

SSPxBUF register.

2. The Buffer Full bit, BF, is set.

3. An ACK pulse is generated.

4. The MSSP Interrupt Flag bit, SSPxIF, is set (and

interrupt is generated, if enabled) on the falling

edge of the ninth SCLx pulse.

In 10-Bit Addressing mode, two address bytes need to

be received by the slave. The five Most Significant bits

(MSbs) of the first address byte specify if this is a 10-bit

address. Bit R/W (SSPxSTAT<2>) must specify a write

so the slave device will receive the second address

byte. For a 10-bit address, the first byte would equal

‘11110 A9 A8 0’, where ‘A9’ and ‘A8’ are the two

MSbs of the address. The sequence of events for 10-bit

addressing is as follows, with steps 7 through 9 for the

slave-transmitter:

1. Receive first (high) byte of address (bits SSPxIF,

BF and UA are set on address match).

2. Update the SSPxADD register with second (low)

byte of address (clears bit UA and releases the

SCLx line).

3. Read the SSPxBUF register (clears bit, BF) and

clear flag bit, SSPxIF.

4. Receive second (low) byte of address (bits

SSPxIF, BF and UA are set).

5. Update the SSPxADD register with the first

(high) byte of address. If match releases SCLx

line, this will clear bit UA.

6. Read the SSPxBUF register (clears bit BF) and

clear flag bit SSPxIF.

7. Receive Repeated Start condition.

8. Receive first (high) byte of address (bits SSPxIF

and BF are set).

9. Read the SSPxBUF register (clears bit BF) and

clear flag bit, SSPxIF.

PIC18F87J50 FAMILY

19.4.3.2 Address Masking Modes

Masking an address bit causes that bit to become a

“don't care”. When one address bit is masked, two

addresses will be Acknowledged and cause an

interrupt. It is possible to mask more than one address

bit at a time, which greatly expands the number of

addresses Acknowledged.

The I2C Slave behaves the same way whether address

masking is used or not. However, when address

masking is used, the I2C slave can Acknowledge

multiple addresses and cause interrupts. When this

occurs, it is necessary to determine which address

caused the interrupt by checking SSPxBUF.

The PIC18F87J10 family of devices is capable of using

two different Address Masking modes in I2C Slave

operation: 5-Bit Address Masking and 7-Bit Address

Masking. The Masking mode is selected at device

configuration using the MSSPMSK Configuration bit.

The default device configuration is 7-bit Address

Masking.

Both Masking modes, in turn, support address masking

of 7-bit and 10-bit addresses. The combination of

Masking modes and addresses provide different

ranges of Acknowledgable addresses for each

combination.

While both Masking modes function in roughly the

same manner, the way they use address masks are

different.

19.4.3.3 5-Bit Address Masking Mode

As the name implies, 5-Bit Address Masking mode

uses an address mask of up to 5 bits to create a range

of addresses to be Acknowledged, using bits 5 through

1 of the incoming address. This allows the module to

Acknowledge up to 31 addresses when using 7-bit

addressing, or 63 addresses with 10-bit addressing

(see Example 19-2). This Masking mode is selected

when the MSSPMSK Configuration bit is programmed

(‘0’).

The address mask in this mode is stored is stored in the

SSPxCON2 register, which stops functioning as a

control register in I2C Slave mode (Register 19-6). In

7-Bit Address Masking mode, address mask bits,

ADMSK<5:1> (SSPxCON2<5:1>), mask the

corresponding address bits in the SSPxADD register.

For any ADMSK bits that are set (ADMSK<n> = 1), the

corresponding address bit is ignored

(SSPxADD<n> = x). For the module to issue an

address Acknowledge, it is sufficient to match only on

addresses that do not have an active address mask.

In 10-Bit Address Masking mode, bits ADMSK<5:2>

mask the corresponding address bits in the SSPxADD

the two LSbs of the address (SSPxADD<1:0>). For any

ADMSK bits that are active (ADMSK<n> = 1), the cor-

responding address bit is ignored (SPxADD<n> = x).

Also note that although in 10-Bit Address Masking

mode, the upper address bits reuse part of the

SSPxADD register bits. The address mask bits do not

interact with those bits; they only affect the lower

address bits.

EXAMPLE 19-2: ADDRESS MASKING EXAMPLES IN 5-BIT MASKING MODE

Note 1: ADMSK1 masks the two Least Significant

bits of the address.

2: The two Most Significant bits of the

address are not affected by address

masking.

7-Bit Addressing:

SSPADD<7:1>= A0h (1010000) (SSPADD<0> is assumed to be 0)

ADMSK<5:1> = 00111

Addresses Acknowledged: A0h, A2h, A4h, A6h, A8h, AAh, ACh, AEh

10-Bit Addressing:

SSPADD<7:0> = A0h (10100000) (The two MSb of the address are ignored in this example, since they

are not affected by masking)

ADMSK<5:1> = 00111

Addresses Acknowledged: A0h, A1h, A2h, A3h, A4h, A5h, A6h, A7h, A8h, A9h, AAh, ABh, ACh, ADh,

AEh, AFh

PIC18F87J50 FAMILY

19.4.3.4 7-Bit Address Masking Mode

Unlike 5-Bit Address Masking mode, 7-Bit Address

Masking mode uses a mask of up to 8 bits (in 10-bit

addressing) to define a range of addresses than can be

Acknowledged, using the lowest bits of the incoming

address. This allows the module to Acknowledge up to

127 different addresses with 7-bit addressing, or 255

with 10-bit addressing (see Example 19-3). This mode

is the default configuration of the module, and is

selected when MSSPMSK is unprogrammed (‘1’).

The address mask for 7-Bit Address Masking mode is

stored in the SSPxMSK register, instead of the

SSPxCON2 register. SSPxMSK is a separate hard-

ware register within the module, but it is not directly

addressable. Instead, it shares an address in the SFR

space with the SSPxADD register. To access the

SSPxMSK register, it is necessary to select MSSP

mode, ‘1001’ (SSPCON1<3:0> = 1001), and then read

or write to the location of SSPxADD.

To use 7-Bit Address Masking mode, it is necessary to

initialize SSPxMSK with a value before selecting the

I2C Slave Addressing mode. Thus, the required

sequence of events is:

1. Select SSPxMSK Access mode

(SSPxCON2<3:0> = 1001).

2. Write the mask value to the appropriate

SSPADD register address (FC8h for MSSP1,

F6Eh for MSSP2).

3. Set the appropriate I2C Slave mode

(SSPxCON2<3:0> = 0111 for 10-bit addressing,

0110 for 7-bit addressing).

Setting or clearing mask bits in SSPxMSK behaves in

the opposite manner of the ADMSK bits in 5-Bit

Address Masking mode. That is, clearing a bit in

SSPxMSK causes the corresponding address bit to be

masked; setting the bit requires a match in that

position. SSPxMSK resets to all ‘1’s upon any Reset

condition and, therefore, has no effect on the standard

MSSP operation until written with a mask value.

With 7-Bit Address Masking mode, SSPxMSK<7:1>

bits mask the corresponding address bits in the

SSPxADD register. For any SSPxMSK bits that are

active (SSPxMSK<n> = 0), the corresponding

SSPxADD address bit is ignored (SSPxADD<n> = x).

For the module to issue an address Acknowledge, it is

sufficient to match only on addresses that do not have

an active address mask.

With 10-Bit Address Masking mode, SSPxMSK<7:0>

bits mask the corresponding address bits in the

SSPxADD register. For any SSPxMSK bits that are

active (= 0), the corresponding SSPxADD address bit

is ignored (SSPxADD<n> = x).

EXAMPLE 19-3: ADDRESS MASKING EXAMPLES IN 7-BIT MASKING MODE

Note: The two Most Significant bits of the

address are not affected by address

masking.

7-Bit Addressing:

SSPxADD<7:1> = 1010 000

SSPxMSK<7:1> = 1111 001

Addresses Acknowledged = A8h, A6h, A4h, A0h

10-Bit Addressing:

SSPxADD<7:0> = 1010 0000 (The two MSb are ignored in this example since they are not affected)

SSPxMSK<5:1> = 1111 0

Addresses Acknowledged = A8h, A6h, A4h, A0h

PIC18F87J50 FAMILY

19.4.3.5 Reception

When the R/W bit of the address byte is clear and an

address match occurs, the R/W bit of the SSPxSTAT

the SSPxBUF register and the SDAx line is held low

(ACK).

When the address byte overflow condition exists, then

the no Acknowledge (ACK) pulse is given. An overflow

condition is defined as either bit, BF (SSPxSTAT<0>),

is set or bit, SSPOV (SSPxCON1<6>), is set.

An MSSP interrupt is generated for each data transfer

byte. The interrupt flag bit, SSPxIF, must be cleared in

software. The SSPxSTAT register is used to determine

the status of the byte.

If SEN is enabled (SSPxCON2<0> = 1), SCLx will be

held low (clock stretch) following each data transfer.

The clock must be released by setting bit, CKP

(SSPxCON1<4>). See Section 19.4.4 “Clock

Stretching” for more details.

19.4.3.6 Transmission

When the R/W bit of the incoming address byte is set

and an address match occurs, the R/W bit of the

SSPxSTAT register is set. The received address is

loaded into the SSPxBUF register. The ACK pulse will

be sent on the ninth bit and pin SCLx is held low regard-

less of SEN (see Section 19.4.4 “Clock Stretching”

for more details). By stretching the clock, the master

will be unable to assert another clock pulse until the

slave is done preparing the transmit data. The transmit

data must be loaded into the SSPxBUF register which

also loads the SSPxSR register. Then, pin SCLx should

be enabled by setting bit, CKP (SSPxCON1<4>). The

eight data bits are shifted out on the falling edge of the

SCLx input. This ensures that the SDAx signal is valid

during the SCLx high time (Figure 19-10).

The ACK pulse from the master-receiver is latched on

the rising edge of the ninth SCLx input pulse. If the

SDAx line is high (not ACK), then the data transfer is

complete. In this case, when the ACK is latched by the

slave, the slave logic is reset (resets the SSPxSTAT

of the Start bit. If the SDAx line was low (ACK), the next

transmit data must be loaded into the SSPxBUF

bit, CKP.

An MSSP interrupt is generated for each data transfer

byte. The SSPxIF bit must be cleared in software and

the SSPxSTAT register is used to determine the status

of the byte. The SSPxIF bit is set on the falling edge of

the ninth clock pulse.

PIC18F87J50 FAMILY

FIGURE 19-8: I2C™ SLAVE MODE TIMING WITH SEN = 0 (RECEPTION, 7-BIT ADDRESS)

SDAx

SCLx

SSPxIF (PIR1<3> or PIR3<7>)

BF (SSPxSTAT<0>)

SSPOV (SSPxCON1<6>)

S1 234 567 89 1 2 345 67 89 1 23 45 7 89 P

A7 A6 A5 A4 A3 A2 A1 D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5 D4 D3 D1 D0

ACK

Receiving Data

ACK

Receiving Data

R/W = 0

ACK

Receiving Address

Cleared in software

SSPxBUF is read

Bus master

terminates

transfer

SSPOV is set

because SSPxBUF is

still full. ACK is not sent.

CKP (SSPxCON1<4>)

(CKP does not reset to ‘0’ when SEN = 0)

PIC18F87J50 FAMILY

FIGURE 19-9: I2C™ SLAVE MODE TIMING WITH SEN = 0 AND ADMSK<5:1> = 01011

(RECEPTION, 7-BIT ADDRESS)

SDAx

SCLx

SSPxIF (PIR1<3> or PIR3<7>)

BF (SSPxSTAT<0>)

SSPOV (SSPxCON1<6>)

S12345678912345678912345 789 P

A7 A6 A5 X A3 X X D7D6D5D4D3D2D1 D0 D7D6D5D4D3 D1D0

ACK

Receiving Data

ACK

Receiving Data

R/W = 0

ACK

Receiving Address

Cleared in software

SSPxBUF is read

Bus master

terminates

transfer

SSPOV is set

because SSPxBUF is

still full. ACK is not sent.

CKP (SSPxCON1<4>)

(CKP does not reset to ‘0’ when SEN = 0)

Note 1: x = Don’t care (i.e., address bit can either be a ‘1’ or a ‘0’).

2: In this example, an address equal to A7.A6.A5.X.A3.X.X will be Acknowledged and cause an interrupt.

PIC18F87J50 FAMILY

FIGURE 19-10: I2C™ SLAVE MODE TIMING (TRANSMISSION, 7-BIT ADDRESS)

SDAx

SCLx

BF (SSPxSTAT<0>)

A6 A5 A4 A3 A2 A1 D6 D5 D4 D3 D2 D1 D0

1 2 3 4 5 6 7 8 2 3 4 5 6 7 8 9

SSPxBUF is written in software

Cleared in software

Data in

sampled

ACK

Transmitting Data

R/W = 0

ACK

Receiving Address

A7 D7

9 1

D6 D5 D4 D3 D2 D1 D0

2 3 4 5 6 7 8 9

SSPxBUF is written in software

Cleared in software

From SSPxIF ISR

Transmitting Data

CKP

(SSPxCON1<4>)

ACK

CKP is set in software CKP is set in software

SCLx held low

while CPU

responds to SSPxIF

SSPxIF (PIR1<3> or PIR3<7>)

From SSPxIF ISR

PIC18F87J50 FAMILY

FIGURE 19-11: I2C™ SLAVE MODE TIMING WITH SEN = 0 AND ADMSK<5:1> = 01001

(RECEPTION, 10-BIT ADDRESS)

SDAx

SCLx

SSPxIF (PIR1<3> or PIR3<7>)

BF (SSPxSTAT<0>)

S123456789 123456789 12345 789 P

1 1 1 1 0 A9 A8 A7 A6 A5 X A3 A2 X X D7 D6 D5 D4 D3 D1 D0

Receive Data Byte

ACK

R/W = 0

ACK

Receive First Byte of Address

Cleared in software

Receive Second Byte of Address

Cleared by hardware

when SSPxADD is updated

with low byte of address

UA (SSPxSTAT<1>)

Clock is held low until

update of SSPxADD has

taken place

UA is set indicating that

the SSPxADD needs to be

updated

UA is set indicating that

SSPxADD needs to be

updated

Cleared by hardware when

SSPxADD is updated with high

byte of address

SSPxBUF is written with

contents of SSPxSR

Dummy read of SSPxBUF

to clear BF flag

ACK

CKP (SSPxCON1<4>)

12345 789

D7 D6 D5 D4 D3 D1 D0

Receive Data Byte

Bus master

terminates

transfer

ACK

Cleared in software Cleared in software

SSPOV (SSPxCON1<6>)

SSPOV is set

because SSPxBUF is

still full. ACK is not sent.

(CKP does not reset to ‘0’ when SEN = 0)

Clock is held low until

update of SSPxADD has

taken place

Note 1: x = Don’t care (i.e., address bit can either be a ‘1’ or a ‘0’).

2: In this example, an address equal to A9.A8.A7.A6.A5.X.A3.A2.X.X will be Acknowledged and cause an interrupt.

3: Note that the Most Significant bits of the address are not affected by the bit masking.

PIC18F87J50 FAMILY

FIGURE 19-12: I2C™ SLAVE MODE TIMING WITH SEN = 0 (RECEPTION, 10-BIT ADDRESS)

SDAx

SCLx

SSPxIF (PIR1<3> or PIR3<7>)

BF (SSPxSTAT<0>)

S123456789 123456789 12345 789 P

1 1 1 1 0 A9A8 A7 A6A5 A4A3A2A1 A0 D7 D6D5D4D3 D1D0

Receive Data Byte

ACK

R/W = 0

ACK

Receive First Byte of Address

Cleared in software

Receive Second Byte of Address

Cleared by hardware

when SSPxADD is updated

with low byte of address

UA (SSPxSTAT<1>)

Clock is held low until

update of SSPxADD has

taken place

UA is set indicating that

the SSPxADD needs to be

updated

UA is set indicating that

SSPxADD needs to be

updated

Cleared by hardware when

SSPxADD is updated with high

byte of address

SSPxBUF is written with

contents of SSPxSR

Dummy read of SSPxBUF

to clear BF flag

ACK

CKP (SSPxCON1<4>)

12345 789

D7 D6 D5 D4 D3 D1 D0

Receive Data Byte

Bus master

terminates

transfer

ACK

Cleared in software Cleared in software

SSPOV (SSPxCON1<6>)

SSPOV is set

because SSPxBUF is

still full. ACK is not sent.

(CKP does not reset to ‘0’ when SEN = 0)

Clock is held low until

update of SSPxADD has

taken place

PIC18F87J50 FAMILY

FIGURE 19-13: I2C™ SLAVE MODE TIMING (TRANSMISSION, 10-BIT ADDRESS)

SDAx

SCLx

SSPxIF (PIR1<3> or PIR3<7>)

BF (SSPxSTAT<0>)

S1234 5 6789 1 23 45 678 9 12345 7 89 P

1 1 1 1 0 A9A8 A7 A6A5A4A3A2A1A0 1 1 1 1 0 A8

R/W = 1

ACK

R/W = 0

ACK

Receive First Byte of Address

Cleared in software

Bus master

terminates

transfer

Receive Second Byte of Address

Cleared by hardware when

SSPxADD is updated with low

byte of address

UA (SSPxSTAT<1>)

Clock is held low until

update of SSPxADD has

taken place

UA is set indicating that

the SSPxADD needs to be

updated

UA is set indicating that

SSPxADD needs to be

updated

Cleared by hardware when

SSPxADD is updated with high

byte of address.

SSPxBUF is written with

contents of SSPxSR

Dummy read of SSPxBUF

to clear BF flag

Receive First Byte of Address

12345 789

D7 D6 D5 D4 D3 D1

ACK

Transmitting Data Byte

Dummy read of SSPxBUF

to clear BF flag

Cleared in software

Write of SSPxBUF

initiates transmit

Cleared in software

Completion of

clears BF flag

CKP (SSPxCON1<4>)

CKP is set in software

CKP is automatically cleared in hardware, holding SCLx low

Clock is held low until

update of SSPxADD has

taken place

data transmission

Clock is held low until

CKP is set to ‘1’

third address sequence

BF flag is clear

at the end of the

PIC18F87J50 FAMILY

19.4.4 CLOCK STRETCHING

Both 7-Bit and 10-Bit Slave modes implement

automatic clock stretching during a transmit sequence.

The SEN bit (SSPxCON2<0>) allows clock stretching

to be enabled during receives. Setting SEN will cause

the SCLx pin to be held low at the end of each data

receive sequence.

19.4.4.1 Clock Stretching for 7-Bit Slave

Receive Mode (SEN = 1)

In 7-Bit Slave Receive mode, on the falling edge of the

ninth clock at the end of the ACK sequence, if the BF

bit is set, the CKP bit in the SSPxCON1 register is

automatically cleared, forcing the SCLx output to be

held low. The CKP bit being cleared to ‘0’ will assert

the SCLx line low. The CKP bit must be set in the

user’s ISR before reception is allowed to continue. By

holding the SCLx line low, the user has time to service

the ISR and read the contents of the SSPxBUF before

the master device can initiate another receive

sequence. This will prevent buffer overruns from

occurring (see Figure 19-15).

19.4.4.2 Clock Stretching for 10-Bit Slave

Receive Mode (SEN = 1)

In 10-Bit Slave Receive mode during the address

sequence, clock stretching automatically takes place

but CKP is not cleared. During this time, if the UA bit is

set after the ninth clock, clock stretching is initiated.

The UA bit is set after receiving the upper byte of the

10-bit address and following the receive of the second

byte of the 10-bit address with the R/W bit cleared to

‘0’. The release of the clock line occurs upon updating

SSPxADD. Clock stretching will occur on each data

receive sequence as described in 7-bit mode.

19.4.4.3 Clock Stretching for 7-Bit Slave

Transmit Mode

The 7-Bit Slave Transmit mode implements clock

stretching by clearing the CKP bit after the falling edge

of the ninth clock if the BF bit is clear. This occurs

regardless of the state of the SEN bit.

The user’s ISR must set the CKP bit before transmis-

sion is allowed to continue. By holding the SCLx line

low, the user has time to service the ISR and load the

contents of the SSPxBUF before the master device

can initiate another transmit sequence (see

Figure 19-10).

19.4.4.4 Clock Stretching for 10-Bit Slave

Transmit Mode

In 10-Bit Slave Transmit mode, clock stretching is

controlled during the first two address sequences by

the state of the UA bit, just as it is in 10-Bit Slave

Receive mode. The first two addresses are followed

by a third address sequence, which contains the

high-order bits of the 10-bit address and the R/W bit

set to ‘1’. After the third address sequence is

performed, the UA bit is not set, the module is now

configured in Transmit mode and clock stretching is

controlled by the BF flag as in 7-Bit Slave Transmit

mode (see Figure 19-13).

Note 1: If the user reads the contents of the

SSPxBUF before the falling edge of the

ninth clock, thus clearing the BF bit, the

CKP bit will not be cleared and clock

stretching will not occur.

2: The CKP bit can be set in software

regardless of the state of the BF bit. The

user should be careful to clear the BF bit

in the ISR before the next receive

sequence in order to prevent an overflow

condition.

Note: If the user polls the UA bit and clears it by

updating the SSPxADD register before the

falling edge of the ninth clock occurs, and

if the user hasn’t cleared the BF bit by

reading the SSPxBUF register before that

time, then the CKP bit will still NOT be

asserted low. Clock stretching on the basis

of the state of the BF bit only occurs during

a data sequence, not an address

sequence.

Note 1: If the user loads the contents of

SSPxBUF, setting the BF bit before the

falling edge of the ninth clock, the CKP bit

will not be cleared and clock stretching

will not occur.

2: The CKP bit can be set in software

regardless of the state of the BF bit.

PIC18F87J50 FAMILY

19.4.4.5 Clock Synchronization and

the CKP bit

When the CKP bit is cleared, the SCLx output is forced

to ‘0’. However, clearing the CKP bit will not assert the

SCLx output low until the SCLx output is already

sampled low. Therefore, the CKP bit will not assert the

SCLx line until an external I2C master device has

already asserted the SCLx line. The SCLx output will

remain low until the CKP bit is set and all other

devices on the I2C bus have deasserted SCLx. This

ensures that a write to the CKP bit will not violate the

minimum high time requirement for SCLx (see

Figure 19-14).

FIGURE 19-14: CLOCK SYNCHRONIZATION TIMING

SDAx

SCLx

DX – 1

Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4

SSPxCON1

CKP

Master device

deasserts clock

Master device

asserts clock

PIC18F87J50 FAMILY

FIGURE 19-15: I2C™ SLAVE MODE TIMING WITH SEN = 1 (RECEPTION, 7-BIT ADDRESS)

SDAx

SCLx

SSPxIF (PIR1<3> or PIR3<7>)

BF (SSPxSTAT<0>)

SSPOV (SSPxCON1<6>)

S1 234 56 7 89 1 2345 67 89 1 23 45 7 89 P

A7 A6 A5 A4 A3 A2 A1 D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5 D4 D3 D1 D0

ACK

Receiving Data

ACK

Receiving Data

R/W = 0

ACK

Receiving Address

Cleared in software

SSPxBUF is read

Bus master

terminates

transfer

SSPOV is set

because SSPxBUF is

still full. ACK is not sent.

CKP (SSPxCON1<4>)

CKP

written

to ‘1’ in

If BF is cleared

prior to the falling

edge of the 9th clock,

CKP will not be reset

to ‘0’ and no clock

stretching will occur

software

Clock is held low until

CKP is set to ‘1’

Clock is not held low

because buffer full bit is

clear prior to falling edge

of 9th clock

Clock is not held low

because ACK =

BF is set after falling

edge of the 9th clock,

CKP is reset to ‘0’ and

clock stretching occurs

PIC18F87J50 FAMILY

FIGURE 19-16: I2C™ SLAVE MODE TIMING WITH SEN = 1 (RECEPTION, 10-BIT ADDRESS)

SDAx

SCLx

SSPxIF (PIR1<3> or PIR3<7>)

BF (SSPxSTAT<0>)

S123456789 123456789 12345 789 P

1 1 1 1 0 A9A8 A7 A6 A5A4A3A2A1 A0 D7D6D5D4D3 D1D0

Receive Data Byte

ACK

R/W = 0

ACK

Receive First Byte of Address

Cleared in software

Receive Second Byte of Address

Cleared by hardware when

SSPxADD is updated with low

byte of address after falling edge

UA (SSPxSTAT<1>)

Clock is held low until

update of SSPxADD has

taken place

UA is set indicating that

the SSPxADD needs to be

updated

UA is set indicating that

SSPxADD needs to be

updated

Cleared by hardware when

SSPxADD is updated with high

byte of address after falling edge

SSPxBUF is written with

contents of SSPxSR Dummy read of SSPxBUF

to clear BF flag

ACK

CKP (SSPxCON1<4>)

12345 789

D7 D6 D5 D4 D3 D1 D0

Receive Data Byte

Bus master

terminates

transfer

ACK

Cleared in software Cleared in software

SSPOV (SSPxCON1<6>)

CKP written to

‘

’

Note: An update of the SSPxADD register before

the falling edge of the ninth clock will have no

effect on UA and UA will remain set.

Note: An update of the SSPxADD

edge of the ninth clock will

have no effect on UA and

UA will remain set.

in software

Clock is held low until

update of SSPxADD has

taken place

of ninth clock

SSPOV is set

because SSPxBUF is

still full. ACK is not sent.

Dummy read of SSPxBUF

to clear BF flag

Clock is held low until

CKP is set to

‘

’

Clock is not held low

because ACK =

PIC18F87J50 FAMILY

19.4.5 GENERAL CALL ADDRESS

SUPPORT

The addressing procedure for the I2C bus is such that

the first byte after the Start condition usually

determines which device will be the slave addressed by

the master. The exception is the general call address

which can address all devices. When this address is

used, all devices should, in theory, respond with an

Acknowledge.

The general call address is one of eight addresses

reserved for specific purposes by the I2C protocol. It

consists of all ‘0’s with R/W = 0.

The general call address is recognized when the

General Call Enable bit, GCEN, is enabled

(SSPxCON2<7> set). Following a Start bit detect, 8 bits

are shifted into the SSPxSR and the address is

compared against the SSPxADD. It is also compared to

the general call address and fixed in hardware.

If the general call address matches, the SSPxSR is

transferred to the SSPxBUF, the BF flag bit is set

(eighth bit), and on the falling edge of the ninth bit (ACK

bit), the SSPxIF interrupt flag bit is set.

When the interrupt is serviced, the source for the

interrupt can be checked by reading the contents of the

SSPxBUF. The value can be used to determine if the

address was device-specific or a general call address.

In 10-bit mode, the SSPxADD is required to be updated

for the second half of the address to match and the UA

bit is set (SSPxSTAT<1>). If the general call address is

sampled when the GCEN bit is set, while the slave is

configured in 10-Bit Addressing mode, then the second

half of the address is not necessary, the UA bit will not

be set and the slave will begin receiving data after the

Acknowledge (Figure 19-17).

FIGURE 19-17: SLAVE MODE GENERAL CALL ADDRESS SEQUENCE

(7 OR 10-BIT ADDRESSING MODE)

SDAx

SCLx

SSPxIF

BF (SSPxSTAT<0>)

SSPOV (SSPxCON1<6>)

Cleared in software

SSPxBUF is read

R/W = 0

ACK

General Call Address

Address is compared to General Call Address

GCEN (SSPxCON2<7>)

Receiving Data ACK

123456789123456789

D7 D6 D5 D4 D3 D2 D1 D0

after ACK, set interrupt

‘0’

‘1’

PIC18F87J50 FAMILY

19.4.6 MASTER MODE

Master mode is enabled by setting and clearing the

appropriate SSPM bits in SSPxCON1 and by setting

the SSPEN bit. In Master mode, the SCLx and SDAx

lines are manipulated by the MSSP hardware if the

TRIS bits are set.

Master mode of operation is supported by interrupt

generation on the detection of the Start and Stop con-

ditions. The Stop (P) and Start (S) bits are cleared from

a Reset or when the MSSP module is disabled. Control

of the I2C bus may be taken when the P bit is set, or the

bus is Idle, with both the S and P bits clear.

In Firmware Controlled Master mode, user code

conducts all I2C bus operations based on Start and

Stop bit conditions.

Once Master mode is enabled, the user has six

options.

1. Assert a Start condition on SDAx and SCLx.

2. Assert a Repeated Start condition on SDAx and

SCLx.

3. Write to the SSPxBUF register initiating

transmission of data/address.

4. Configure the I2C port to receive data.

5. Generate an Acknowledge condition at the end

of a received byte of data.

6. Generate a Stop condition on SDAx and SCLx.

The following events will cause the MSSP Interrupt

Flag bit, SSPxIF, to be set (and MSSP interrupt, if

enabled):

• Start condition

• Stop condition

• Data transfer byte transmitted/received

• Acknowledge transmitted

• Repeated Start

FIGURE 19-18: MSSPx BLOCK DIAGRAM (I2C™ MASTER MODE)

Note: The MSSP module, when configured in

I2C Master mode, does not allow queueing

of events. For instance, the user is not

allowed to initiate a Start condition and

immediately write the SSPxBUF register to

initiate transmission before the Start

condition is complete. In this case, the

SSPxBUF will not be written to and the

WCOL bit will be set, indicating that a write

to the SSPxBUF did not occur.

Read Write

SSPxSR

Start bit, Stop bit,

SSPxBUF

Internal

Data Bus

Set/Reset S, P (SSPxSTAT), WCOL (SSPxCON1)

Shift

Clock

MSb LSb

SDAx

Acknowledge

Generate

Stop bit Detect

Write Collision Detect

Clock Arbitration

State Counter for

End of XMIT/RCV

SCLx

SCLx In

Bus Collision

SDAx In

Receive Enable

Clock Cntl

Clock Arbitrate/WCOL Detect

(hold off clock source)

SSPxADD<6:0>

Baud

Set SSPxIF, BCLxIF

Reset ACKSTAT, PEN (SSPxCON2)

Rate

Generator

SSPM3:SSPM0

Start bit Detect

PIC18F87J50 FAMILY

19.4.6.1 I2C Master Mode Operation

The master device generates all of the serial clock

pulses and the Start and Stop conditions. A transfer is

ended with a Stop condition or with a Repeated Start

condition. Since the Repeated Start condition is also

the beginning of the next serial transfer, the I2C bus will

not be released.

In Master Transmitter mode, serial data is output

through SDAx while SCLx outputs the serial clock. The

first byte transmitted contains the slave address of the

receiving device (7 bits) and the Read/Write (R/W) bit.

In this case, the R/W bit will be logic ‘0’. Serial data is

transmitted 8 bits at a time. After each byte is transmit-

ted, an Acknowledge bit is received. Start and Stop

conditions are output to indicate the beginning and the

end of a serial transfer.

In Master Receive mode, the first byte transmitted

contains the slave address of the transmitting device

(7 bits) and the R/W bit. In this case, the R/W bit will be

logic ‘1’. Thus, the first byte transmitted is a 7-bit slave

address, followed by a ‘1’ to indicate the receive bit.

Serial data is received via SDAx, while SCLx outputs

the serial clock. Serial data is received 8 bits at a time.

After each byte is received, an Acknowledge bit is

transmitted. Start and Stop conditions indicate the

beginning and end of transmission.

The Baud Rate Generator, used for the SPI mode

operation, is used to set the SCLx clock frequency for

either 100 kHz, 400 kHz or 1 MHz I2C operation. See

Section 19.4.7 “Baud Rate” for more details.

A typical transmit sequence would go as follows:

1. The user generates a Start condition by setting

the Start Enable bit, SEN (SSPxCON2<0>).

2. SSPxIF is set. The MSSP module will wait the

required start time before any other operation

takes place.

3. The user loads the SSPxBUF with the slave

address to transmit.

4. Address is shifted out the SDAx pin until all 8 bits

are transmitted.

5. The MSSP module shifts in the ACK bit from the

slave device and writes its value into the

SSPxCON2 register (SSPxCON2<6>).

6. The MSSP module generates an interrupt at the

end of the ninth clock cycle by setting the

SSPxIF bit.

7. The user loads the SSPxBUF with eight bits of

data.

8. Data is shifted out the SDAx pin until all 8 bits

are transmitted.

9. The MSSP module shifts in the ACK bit from the

slave device and writes its value into the

SSPxCON2 register (SSPxCON2<6>).

10. The MSSP module generates an interrupt at the

end of the ninth clock cycle by setting the

SSPxIF bit.

11. The user generates a Stop condition by setting

the Stop Enable bit, PEN (SSPxCON2<2>).

12. Interrupt is generated once the Stop condition is

complete.

PIC18F87J50 FAMILY

19.4.7 BAUD RATE

In I2C Master mode, the Baud Rate Generator (BRG)

reload value is placed in the lower 7 bits of the

SSPxADD register (Figure 19-19). When a write

occurs to SSPxBUF, the Baud Rate Generator will

automatically begin counting. The BRG counts down to

0 and stops until another reload has taken place. The

BRG count is decremented twice per instruction cycle

CY) on the Q2 and Q4 clocks. In I2C Master mode, the

BRG is reloaded automatically.

Once the given operation is complete (i.e., transmis-

sion of the last data bit is followed by ACK), the internal

clock will automatically stop counting and the SCLx pin

will remain in its last state.

Table 19-3 demonstrates clock rates based on

instruction cycles and the BRG value loaded into

SSPxADD.

19.4.7.1 Baud Rate and Module

Interdependence

Because MSSP1 and MSSP2 are independent, they

can operate simultaneously in I2C Master mode at

different baud rates. This is done by using different

BRG reload values for each module.

Because this mode derives its basic clock source from

the system clock, any changes to the clock will affect

both modules in the same proportion. It may be

possible to change one or both baud rates back to a

previous value by changing the BRG reload value.

FIGURE 19-19: BAUD RATE GENERATOR BLOCK DIAGRAM

TABLE 19-3: I2C™ CLOCK RATE w/BRG

SSPM3:SSPM0

BRG Down Counter

CLKO FOSC/4

SSPxADD<6:0>

SSPM3:SSPM0

SCLx

Reload

Control

Reload

FOSC FCY FCY * 2 BRG Value FSCL

(2 Rollovers of BRG)

40 MHz 10 MHz 20 MHz 18h 400 kHz(1)

40 MHz 10 MHz 20 MHz 1Fh 312.5 kHz

40 MHz 10 MHz 20 MHz 63h 100 kHz

16 MHz 4 MHz 8 MHz 09h 400 kHz(1)

16 MHz 4 MHz 8 MHz 0Ch 308 kHz

16 MHz 4 MHz 8 MHz 27h 100 kHz

4 MHz 1 MHz 2 MHz 02h 333 kHz(1)

4 MHz 1 MHz 2 MHz 09h 100 kHz

4 MHz 1 MHz 2 MHz 00h 1 MHz(1)

Note 1: The I2C interface does not conform to the 400 kHz I2C specification (which applies to rates greater than

100 kHz) in all details, but may be used with care where higher rates are required by the application.

PIC18F87J50 FAMILY

19.4.7.2 Clock Arbitration

Clock arbitration occurs when the master, during any

receive, transmit or Repeated Start/Stop condition,

deasserts the SCLx pin (SCLx allowed to float high).

When the SCLx pin is allowed to float high, the Baud

Rate Generator (BRG) is suspended from counting

until the SCLx pin is actually sampled high. When the

SCLx pin is sampled high, the Baud Rate Generator is

reloaded with the contents of SSPxADD<6:0> and

begins counting. This ensures that the SCLx high time

will always be at least one BRG rollover count in the

event that the clock is held low by an external device

(Figure 19-20).

FIGURE 19-20: BAUD RATE GENERATOR TIMING WITH CLOCK ARBITRATION

SDAx

SCLx

SCLx deasserted but slave holds

DX – 1DX

BRG

SCLx is sampled high, reload takes

place and BRG starts its count

03h 02h 01h 00h (hold off) 03h 02h

Reload

BRG

Value

SCLx low (clock arbitration)

SCLx allowed to transition high

BRG decrements on

Q2 and Q4 cycles

PIC18F87J50 FAMILY

19.4.8 I2C MASTER MODE START

CONDITION TIMING

To initiate a Start condition, the user sets the Start

Enable bit, SEN (SSPxCON2<0>). If the SDAx and

SCLx pins are sampled high, the Baud Rate Generator

is reloaded with the contents of SSPxADD<6:0> and

starts its count. If SCLx and SDAx are both sampled

high when the Baud Rate Generator times out (TBRG),

the SDAx pin is driven low. The action of the SDAx

being driven low while SCLx is high is the Start condi-

tion and causes the S bit (SSPxSTAT<3>) to be set.

Following this, the Baud Rate Generator is reloaded

with the contents of SSPxADD<6:0> and resumes its

count. When the Baud Rate Generator times out

(TBRG), the SEN bit (SSPxCON2<0>) will be

automatically cleared by hardware. The Baud Rate

Generator is suspended, leaving the SDAx line held low

and the Start condition is complete.

19.4.8.1 WCOL Status Flag

If the user writes the SSPxBUF when a Start sequence

is in progress, the WCOL bit is set and the contents of

the buffer are unchanged (the write doesn’t occur).

FIGURE 19-21: FIRST START BIT TIMING

Note: If, at the beginning of the Start condition,

the SDAx and SCLx pins are already sam-

pled low or if during the Start condition, the

SCLx line is sampled low before the SDAx

line is driven low, a bus collision occurs,

the Bus Collision Interrupt Flag, BCLxIF, is

set, the Start condition is aborted and the

I2C module is reset into its Idle state.

Note: Because queueing of events is not

allowed, writing to the lower 5 bits of

SSPxCON2 is disabled until the Start

condition is complete.

SDAx

SCLx

TBRG

1st bit 2nd bit

TBRG

SDAx = 1, At completion of Start bit,

SCLx = 1

Write to SSPxBUF occurs here

TBRG

hardware clears SEN bit

TBRG

Write to SEN bit occurs here Set S bit (SSPxSTAT<3>)

and sets SSPxIF bit

PIC18F87J50 FAMILY

19.4.9 I2C MASTER MODE REPEATED

START CONDITION TIMING

A Repeated Start condition occurs when the RSEN bit

(SSPxCON2<1>) is programmed high and the I2C logic

module is in the Idle state. When the RSEN bit is set,

the SCLx pin is asserted low. When the SCLx pin is

sampled low, the Baud Rate Generator is loaded with

the contents of SSPxADD<5:0> and begins counting.

The SDAx pin is released (brought high) for one Baud

Rate Generator count (TBRG). When the Baud Rate

Generator times out, and if SDAx is sampled high, the

SCLx pin will be deasserted (brought high). When

SCLx is sampled high, the Baud Rate Generator is

reloaded with the contents of SSPxADD<6:0> and

begins counting. SDAx and SCLx must be sampled

high for one TBRG. This action is then followed by

assertion of the SDAx pin (SDAx = 0) for one TBRG

while SCLx is high. Following this, the RSEN bit

(SSPxCON2<1>) will be automatically cleared and the

Baud Rate Generator will not be reloaded, leaving the

SDAx pin held low. As soon as a Start condition is

detected on the SDAx and SCLx pins, the S bit

(SSPxSTAT<3>) will be set. The SSPxIF bit will not be

set until the Baud Rate Generator has timed out.

Immediately following the SSPxIF bit getting set, the

user may write the SSPxBUF with the 7-bit address in

7-bit mode, or the default first address in 10-bit mode.

After the first eight bits are transmitted and an ACK is

received, the user may then transmit an additional eight

bits of address (10-bit mode) or eight bits of data (7-bit

mode).

19.4.9.1 WCOL Status Flag

If the user writes the SSPxBUF when a Repeated Start

sequence is in progress, the WCOL is set and the

contents of the buffer are unchanged (the write doesn’t

occur).

FIGURE 19-22: REPEATED START CONDITION WAVEFORM

Note 1: If RSEN is programmed while any other

event is in progress, it will not take effect.

2: A bus collision during the Repeated Start

condition occurs if:

• SDAx is sampled low when SCLx

goes from low-to-high.

• SCLx goes low before SDAx is

asserted low. This may indicate that

another master is attempting to

transmit a data ‘1’.

Note: Because queueing of events is not

allowed, writing of the lower 5 bits of

SSPxCON2 is disabled until the Repeated

Start condition is complete.

SDAx

SCLx

Sr = Repeated Start

Write to SSPxCON2

Write to SSPxBUF occurs here

on falling edge of ninth clock,

end of XMIT

At completion of Start bit,

hardware clears RSEN bit

1st bit

S bit set by hardware

TBRG

SDAx = 1,

SCLx (no change).

SCLx = 1

occurs here:

and sets SSPxIF

RSEN bit set by hardware

TBRG

TBRG TBRG TBRG

PIC18F87J50 FAMILY

19.4.10 I2C MASTER MODE TRANSMISSION

Transmission of a data byte, a 7-bit address or the

other half of a 10-bit address, is accomplished by sim-

ply writing a value to the SSPxBUF register. This action

will set the Buffer Full flag bit, BF, and allow the Baud

Rate Generator to begin counting and start the next

transmission. Each bit of address/data will be shifted

out onto the SDAx pin after the falling edge of SCLx is

asserted (see data hold time specification

parameter 106). SCLx is held low for one Baud Rate

Generator rollover count (TBRG). Data should be valid

before SCLx is released high (see data setup time

specification parameter 107). When the SCLx pin is

released high, it is held that way for TBRG. The data on

the SDAx pin must remain stable for that duration and

some hold time after the next falling edge of SCLx.

After the eighth bit is shifted out (the falling edge of the

eighth clock), the BF flag is cleared and the master

releases SDAx. This allows the slave device being

addressed to respond with an ACK bit during the ninth

bit time if an address match occurred, or if data was

received properly. The status of ACK is written into the

ACKDT bit on the falling edge of the ninth clock. If the

master receives an Acknowledge, the Acknowledge

Status bit, ACKSTAT, is cleared; if not, the bit is set.

After the ninth clock, the SSPxIF bit is set and the

master clock (Baud Rate Generator) is suspended until

the next data byte is loaded into the SSPxBUF, leaving

SCLx low and SDAx unchanged (Figure 19-23).

After the write to the SSPxBUF, each bit of the address

will be shifted out on the falling edge of SCLx until all

seven address bits and the R/W bit are completed. On

the falling edge of the eighth clock, the master will

deassert the SDAx pin, allowing the slave to respond

with an Acknowledge. On the falling edge of the ninth

clock, the master will sample the SDAx pin to see if the

address was recognized by a slave. The status of the

ACK bit is loaded into the ACKSTAT status bit

(SSPxCON2<6>). Following the falling edge of the

ninth clock transmission of the address, the SSPxIF

flag is set, the BF flag is cleared and the Baud Rate

Generator is turned off until another write to the

SSPxBUF takes place, holding SCLx low and allowing

SDAx to float.

19.4.10.1 BF Status Flag

In Transmit mode, the BF bit (SSPxSTAT<0>) is set

when the CPU writes to SSPxBUF and is cleared when

all 8 bits are shifted out.

19.4.10.2 WCOL Status Flag

If the user writes the SSPxBUF when a transmit is

already in progress (i.e., SSPxSR is still shifting out a

data byte), the WCOL bit is set and the contents of the

buffer are unchanged (the write doesn’t occur) after

CY after the SSPxBUF write. If SSPxBUF is rewritten

within 2 TCY, the WCOL bit is set and SSPxBUF is

updated. This may result in a corrupted transfer.

The user should verify that the WCOL bit is clear after

each write to SSPxBUF to ensure the transfer is correct.

In all cases, WCOL must be cleared in software.

19.4.10.3 ACKSTAT Status Flag

In Transmit mode, the ACKSTAT bit (SSPxCON2<6>)

is cleared when the slave has sent an Acknowledge

(ACK =0) and is set when the slave does not Acknowl-

edge (ACK = 1). A slave sends an Acknowledge when

it has recognized its address (including a general call),

or when the slave has properly received its data.

19.4.11 I2C MASTER MODE RECEPTION

Master mode reception is enabled by programming the

Receive Enable bit, RCEN (SSPxCON2<3>).

The Baud Rate Generator begins counting and on each

rollover, the state of the SCLx pin changes

(high-to-low/low-to-high) and data is shifted into the

SSPxSR. After the falling edge of the eighth clock, the

receive enable flag is automatically cleared, the con-

tents of the SSPxSR are loaded into the SSPxBUF, the

BF flag bit is set, the SSPxIF flag bit is set and the Baud

Rate Generator is suspended from counting, holding

SCLx low. The MSSP is now in Idle state awaiting the

next command. When the buffer is read by the CPU,

the BF flag bit is automatically cleared. The user can

then send an Acknowledge bit at the end of reception

by setting the Acknowledge Sequence Enable bit,

ACKEN (SSPxCON2<4>).

19.4.11.1 BF Status Flag

In receive operation, the BF bit is set when an address

or data byte is loaded into SSPxBUF from SSPxSR. It

is cleared when the SSPxBUF register is read.

19.4.11.2 SSPOV Status Flag

In receive operation, the SSPOV bit is set when 8 bits

are received into the SSPxSR and the BF flag bit is

already set from a previous reception.

19.4.11.3 WCOL Status Flag

If the user writes the SSPxBUF when a receive is

already in progress (i.e., SSPxSR is still shifting in a

data byte), the WCOL bit is set and the contents of the

buffer are unchanged (the write doesn’t occur).

Note: The MSSP module must be in an inactive

state before the RCEN bit is set or the

RCEN bit will be disregarded.

PIC18F87J50 FAMILY

FIGURE 19-23: I2C™ MASTER MODE WAVEFORM (TRANSMISSION, 7 OR 10-BIT ADDRESS)

SDAx

SCLx

SSPxIF

BF (SSPxSTAT<0>)

SEN

A7 A6 A5 A4 A3 A2 A1 ACK = 0D7 D6 D5 D4 D3 D2 D1 D0

ACK

Transmitting Data or Second Half

R/W = 0Transmit Address to Slave

123456789 123456789 P

Cleared in software service routine

SSPxBUF is written in software

from MSSP interrupt

After Start condition, SEN cleared by hardware

SSPxBUF written with 7-bit address and R/W,

start transmit

SCLx held low

while CPU

responds to SSPxIF

SEN = 0

of 10-bit Address

Write SSPxCON2<0> (SEN = 1),

Start condition begins From slave, clear ACKSTAT bit (SSPxCON2<6>)

ACKSTAT in

SSPxCON2 = 1

Cleared in software

SSPxBUF written

PEN

R/W

Cleared in software

PIC18F87J50 FAMILY

FIGURE 19-24: I2C™ MASTER MODE WAVEFORM (RECEPTION, 7-BIT ADDRESS)

D3D4

D6D7

A7 A6 A5 A4 A3 A2 A1

SDAx

SCLx 12

345678912345678 9 1234

Bus master

terminates

transfer

ACK

Receiving Data from Slave

D3D4

D6D7

ACK

R/W = 0

Transmit Address to Slave

SSPxIF

ACK is not sent

Write to SSPxCON2<0> (SEN = 1),

Write to SSPxBUF occurs here, ACK from Slave

Master configured as a receiver

by programming SSPxCON2<3> (RCEN = 1)

PEN bit = 1

written here

Data shifted in on falling edge of CLK

Cleared in software

start XMIT

SEN = 0

SSPOV

SDAx = 0, SCLx = 1,

while CPU

(SSPxSTAT<0>)

ACK

Cleared in software

Set SSPxIF interrupt

at end of receive

Set P bit

(SSPxSTAT<4>)

and SSPxIF

ACK from master,

Set SSPxIF at end

Set SSPxIF interrupt

at end of Acknowledge

sequence

Set SSPxIF interrupt

at end of Acknowledge

sequence

of receive

Set ACKEN, start Acknowledge sequence,

SDAx = ACKDT = 1

RCEN cleared

automatically

RCEN = 1, start

next receive

Write to SSPxCON2<4>

to start Acknowledge sequence,

SDAx = ACKDT (SSPxCON2<5>) = 0

RCEN cleared

automatically

responds to SSPxIF

ACKEN

begin Start condition

Cleared in software

SDAx = ACKDT = 0

Last bit is shifted into SSPxSR and

contents are unloaded into SSPxBUF

Cleared in

software

SSPOV is set because

SSPxBUF is still full

PIC18F87J50 FAMILY

19.4.12 ACKNOWLEDGE SEQUENCE

TIMING

An Acknowledge sequence is enabled by setting the

Acknowledge Sequence Enable bit, ACKEN

(SSPxCON2<4>). When this bit is set, the SCLx pin is

pulled low and the contents of the Acknowledge data bit

are presented on the SDAx pin. If the user wishes to

generate an Acknowledge, then the ACKDT bit should

be cleared. If not, the user should set the ACKDT bit

before starting an Acknowledge sequence. The Baud

Rate Generator then counts for one rollover period

(TBRG) and the SCLx pin is deasserted (pulled high).

When the SCLx pin is sampled high (clock arbitration),

the Baud Rate Generator counts for TBRG; the SCLx pin

is then pulled low. Following this, the ACKEN bit is auto-

matically cleared, the Baud Rate Generator is turned off

and the MSSP module then goes into an inactive state

(Figure 19-25).

19.4.12.1 WCOL Status Flag

If the user writes the SSPxBUF when an Acknowledge

sequence is in progress, then WCOL is set and the

contents of the buffer are unchanged (the write doesn’t

occur).

19.4.13 STOP CONDITION TIMING

A Stop bit is asserted on the SDAx pin at the end of a

receive/transmit by setting the Stop Sequence Enable

bit, PEN (SSPxCON2<2>). At the end of a

receive/transmit, the SCLx line is held low after the

falling edge of the ninth clock. When the PEN bit is set,

the master will assert the SDAx line low. When the

SDAx line is sampled low, the Baud Rate Generator is

reloaded and counts down to 0. When the Baud Rate

Generator times out, the SCLx pin will be brought high

and one TBRG (Baud Rate Generator rollover count)

later, the SDAx pin will be deasserted. When the SDAx

pin is sampled high while SCLx is high, the P bit

(SSPxSTAT<4>) is set. A TBRG later, the PEN bit is

cleared and the SSPxIF bit is set (Figure 19-26).

19.4.13.1 WCOL Status Flag

If the user writes the SSPxBUF when a Stop sequence

is in progress, then the WCOL bit is set and the

contents of the buffer are unchanged (the write doesn’t

occur).

FIGURE 19-25: ACKNOWLEDGE SEQUENCE WAVEFORM

FIGURE 19-26: STOP CONDITION RECEIVE OR TRANSMIT MODE

Note: TBRG = one Baud Rate Generator period.

SDAx

SCLx

SSPxIF set at

Acknowledge sequence starts here,

write to SSPxCON2, ACKEN automatically cleared

Cleared in

TBRG TBRG

the end of receive

ACKEN = 1, ACKDT = 0

SSPxIF

software SSPxIF set at the end

of Acknowledge sequence

Cleared in

software

ACK

SCLx

SDAx

SDAx asserted low before rising edge of clock

Write to SSPxCON2,

set PEN

Falling edge of

SCLx = 1 for TBRG, followed by SDAx = 1 for TBRG

9th clock

SCLx brought high after TBRG

Note: TBRG = one Baud Rate Generator period.

TBRG TBRG

after SDAx sampled high. P bit (SSPxSTAT<4>) is set

TBRG

to set up Stop condition

ACK

TBRG

PEN bit (SSPxCON2<2>) is cleared by

hardware and the SSPxIF bit is set

PIC18F87J50 FAMILY

19.4.14 SLEEP OPERATION

While in Sleep mode, the I2C module can receive

addresses or data and when an address match or

complete byte transfer occurs, wake the processor

from Sleep (if the MSSP interrupt is enabled).

19.4.15 EFFECTS OF A RESET

A Reset disables the MSSP module and terminates the

current transfer.

19.4.16 MULTI-MASTER MODE

In Multi-Master mode, the interrupt generation on the

detection of the Start and Stop conditions allows the

determination of when the bus is free. The Stop (P) and

Start (S) bits are cleared from a Reset or when the

MSSP module is disabled. Control of the I2C bus may

be taken when the P bit (SSPxSTAT<4>) is set, or the

bus is Idle, with both the S and P bits clear. When the

bus is busy, enabling the MSSP interrupt will generate

the interrupt when the Stop condition occurs.

In multi-master operation, the SDAx line must be

monitored for arbitration to see if the signal level is the

expected output level. This check is performed in

hardware with the result placed in the BCLxIF bit.

The states where arbitration can be lost are:

• Address Transfer

• Data Transfer

• A Start Condition

• A Repeated Start Condition

• An Acknowledge Condition

19.4.17 MULTI -MASTER COMMUNICATION,

BUS COLLISION AND BUS

ARBITRATION

Multi-Master mode support is achieved by bus arbitra-

tion. When the master outputs address/data bits onto

the SDAx pin, arbitration takes place when the master

outputs a ‘1’ on SDAx, by letting SDAx float high and

another master asserts a ‘0’. When the SCLx pin floats

high, data should be stable. If the expected data on

SDAx is a ‘1’ and the data sampled on the SDAx

pin = 0, then a bus collision has taken place. The

master will set the Bus Collision Interrupt Flag, BCLxIF

and reset the I2C port to its Idle state (Figure 19-27).

If a transmit was in progress when the bus collision

occurred, the transmission is halted, the BF flag is

cleared, the SDAx and SCLx lines are deasserted and

the SSPxBUF can be written to. When the user services

the bus collision Interrupt Service Routine and if the I2C

bus is free, the user can resume communication by

asserting a Start condition.

If a Start, Repeated Start, Stop or Acknowledge condition

was in progress when the bus collision occurred, the con-

dition is aborted, the SDAx and SCLx lines are

deasserted and the respective control bits in the

SSPxCON2 register are cleared. When the user services

the bus collision Interrupt Service Routine, and if the I2C

bus is free, the user can resume communication by

asserting a Start condition.

The master will continue to monitor the SDAx and SCLx

pins. If a Stop condition occurs, the SSPxIF bit will be set.

A write to the SSPxBUF will start the transmission of

data at the first data bit regardless of where the

transmitter left off when the bus collision occurred.

In Multi-Master mode, the interrupt generation on the

detection of Start and Stop conditions allows the deter-

mination of when the bus is free. Control of the I2C bus

can be taken when the P bit is set in the SSPxSTAT

cleared.

FIGURE 19-27: BUS COLLISION TIMING FOR TRANSMIT AND ACKNOWLEDGE

SDAx

SCLx

BCLxIF

SDAx released

SDAx line pulled low

by another source

Sample SDAx. While SCLx is high,

data doesn’t match what is driven

bus collision has occurred

Set bus collision

interrupt (BCLxIF)

by the master;

by master

Data changes

while SCLx = 0

PIC18F87J50 FAMILY

19.4.17.1 Bus Collision During a Start

Condition

During a Start condition, a bus collision occurs if:

a) SDAx or SCLx is sampled low at the beginning

of the Start condition (Figure 19-28).

b) SCLx is sampled low before SDAx is asserted

low (Figure 19-29).

During a Start condition, both the SDAx and the SCLx

pins are monitored.

If the SDAx pin is already low, or the SCLx pin is

already low, then all of the following occur:

• the Start condition is aborted,

• the BCLxIF flag is set and

• the MSSP module is reset to its inactive state

(Figure 19-28)

The Start condition begins with the SDAx and SCLx

pins deasserted. When the SDAx pin is sampled high,

the Baud Rate Generator is loaded from

SSPxADD<6:0> and counts down to 0. If the SCLx pin

is sampled low while SDAx is high, a bus collision

occurs because it is assumed that another master is

attempting to drive a data ‘1’ during the Start condition.

If the SDAx pin is sampled low during this count, the

BRG is reset and the SDAx line is asserted early

(Figure 19-30). If, however, a ‘1’ is sampled on the

SDAx pin, the SDAx pin is asserted low at the end of

the BRG count. The Baud Rate Generator is then

reloaded and counts down to 0. If the SCLx pin is

sampled as ‘0’ during this time, a bus collision does not

occur. At the end of the BRG count, the SCLx pin is

asserted low.

FIGURE 19-28: BUS COLLISION DURING START CONDITION (SDAx ONLY)

Note: The reason that bus collision is not a factor

during a Start condition is that no two bus

masters can assert a Start condition at the

exact same time. Therefore, one master

will always assert SDAx before the other.

This condition does not cause a bus colli-

sion because the two masters must be

allowed to arbitrate the first address

following the Start condition. If the address

is the same, arbitration must be allowed to

continue into the data portion, Repeated

Start or Stop conditions.

SDAx

SCLx

SEN

SDAx sampled low before

SDAx goes low before the SEN bit is set.

S bit and SSPxIF set because

MSSP module reset into Idle state.

SEN cleared automatically because of bus collision.

S bit and SSPxIF set because

Set SEN, enable Start

condition if SDAx = 1, SCLx = 1

SDAx = 0, SCLx = 1.

BCLxIF

SSPxIF

SDAx = 0, SCLx = 1.

SSPxIF and BCLxIF are

cleared in software

SSPxIF and BCLxIF are

cleared in software

Set BCLxIF,

Start condition. Set BCLxIF.

PIC18F87J50 FAMILY

FIGURE 19-29: BUS COLLISION DURING START CONDITION (SCLx = 0)

FIGURE 19-30: BRG RESET DUE TO SDAx ARBITRATION DURING START CONDITION

SDAx

SCLx

SEN bus collision occurs. Set BCLxIF.

SCLx = 0 before SDAx = 0,

Set SEN, enable Start

sequence if SDAx = 1, SCLx = 1

TBRG TBRG

SDAx = 0, SCLx = 1

BCLxIF

SSPxIF

Interrupt cleared

in software

bus collision occurs. Set BCLxIF.

SCLx = 0 before BRG time-out,

‘0’‘0’

SDAx

SCLx

SEN

Set S

Less than TBRG TBRG

SDAx = 0, SCLx = 1

BCLxIF

SSPxIF

Interrupts cleared

in software

set SSPxIF

SDAx = 0, SCLx = 1,

SCLx pulled low after BRG

time-out

Set SSPxIF

‘0’

SDAx pulled low by other master.

Reset BRG and assert SDAx.

Set SEN, enable Start

sequence if SDAx = 1, SCLx = 1

PIC18F87J50 FAMILY

19.4.17.2 Bus Collision During a Repeated

Start Condition

During a Repeated Start condition, a bus collision

occurs if:

a) A low level is sampled on SDAx when SCLx

goes from a low level to a high level.

b) SCLx goes low before SDAx is asserted low,

indicating that another master is attempting to

transmit a data ‘1’.

When the user deasserts SDAx and the pin is allowed

to float high, the BRG is loaded with SSPxADD<6:0>

and counts down to 0. The SCLx pin is then deasserted

and when sampled high, the SDAx pin is sampled.

If SDAx is low, a bus collision has occurred (i.e., another

master is attempting to transmit a data ‘0’, see

Figure 19-31). If SDAx is sampled high, the BRG is

reloaded and begins counting. If SDAx goes from

high-to-low before the BRG times out, no bus collision

occurs because no two masters can assert SDAx at

exactly the same time.

If SCLx goes from high-to-low before the BRG times

out and SDAx has not already been asserted, a bus

collision occurs. In this case, another master is

attempting to transmit a data ‘1’ during the Repeated

Start condition (see Figure 19-32).

If, at the end of the BRG time-out, both SCLx and SDAx

are still high, the SDAx pin is driven low and the BRG is

reloaded and begins counting. At the end of the count,

regardless of the status of the SCLx pin, the SCLx pin is

driven low and the Repeated Start condition is complete.

FIGURE 19-31: BUS COLLISION DURING A REPEATED START CONDITION (CASE 1)

FIGURE 19-32: BUS COLLISION DURING REPEATED START CONDITION (CASE 2)

SDAx

SCLx

RSEN

BCLxIF

SSPxIF

Sample SDAx when SCLx goes high.

If SDAx = 0, set BCLxIF and release SDAx and SCLx.

Cleared in software

‘0’

SDAx

SCLx

BCLxIF

RSEN

SSPxIF

Interrupt cleared

in software

SCLx goes low before SDAx,

set BCLxIF. Release SDAx and SCLx.

TBRG TBRG

‘0’

PIC18F87J50 FAMILY

19.4.17.3 Bus Collision During a Stop

Condition

Bus collision occurs during a Stop condition if:

a) After the SDAx pin has been deasserted and

allowed to float high, SDAx is sampled low after

the BRG has timed out.

b) After the SCLx pin is deasserted, SCLx is

sampled low before SDAx goes high.

The Stop condition begins with SDAx asserted low.

When SDAx is sampled low, the SCLx pin is allowed to

float. When the pin is sampled high (clock arbitration),

the Baud Rate Generator is loaded with

SSPxADD<6:0> and counts down to 0. After the BRG

times out, SDAx is sampled. If SDAx is sampled low, a

bus collision has occurred. This is due to another

master attempting to drive a data ‘0’ (Figure 19-33). If

the SCLx pin is sampled low before SDAx is allowed to

float high, a bus collision occurs. This is another case

of another master attempting to drive a data ‘0’

(Figure 19-34).

FIGURE 19-33: BUS COLLISION DURING A STOP CONDITION (CASE 1)

FIGURE 19-34: BUS COLLISION DURING A STOP CONDITION (CASE 2)

SDAx

SCLx

BCLxIF

PEN

SSPxIF

TBRG TBRG TBRG

SDAx asserted low

SDAx sampled

low after TBRG,

set BCLxIF

‘0’

SDAx

SCLx

BCLxIF

PEN

SSPxIF

TBRG TBRG TBRG

Assert SDAx SCLx goes low before SDAx goes high,

set BCLxIF

‘0’

PIC18F87J50 FAMILY

TABLE 19-4: REGISTERS ASSOCIATED WITH I2C™ OPERATION

Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Reset

Values

on Page:

INTCON GIE/GIEH PEIE/GIEL TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 61

PIR1 PMPIF ADIF RC1IF TX1IF SSP1IF CCP1IF TMR2IF TMR1IF 64

PIE1 PMPIE ADIE RC1IE TX1IE SSP1IE CCP1IE TMR2IE TMR1IE 64

IPR1 PMPIP ADIP RC1IP TX1IP SSP1IP CCP1IP TMR2IP TMR1IP 64

PIR2 OSCFIF CM2IF CM1IF USBIF BCL1IF LVDIF TMR3IF CCP2IF 64

PIE2 OSCFIE CM2IE CM1IE USBIE BCL1IE LVDIE TMR3IE CCP2IE 64

IPR2 OSCFIP CM2IP CM1IP USBIP BCL1IP LVDIP TMR3IP CCP2IP 64

PIR3 SSP2IF BCL2IF RC2IF TX2IF TMR4IF CCP5IF CCP4IF CCP3IF 64

PIE3 SSP2IE BCL2IE RC2IE TX2IE TMR4IE CCP5IE CCP4IE CCP3IE 64

IPR3 SSP2IP BCL2IP RC2IP TX2IP TMR4IP CCP5IP CCP4IP CCP3IP 64

TRISC TRISC7 TRISC6 TRISC5 TRISC4 TRISC3 TRISC2 TRISC1 TRISC0 64

TRISD TRISD7 TRISD6 TRISD5 TRISD4 TRISD3 TRISD2 TRISD1 TRISD0 64

SSP1BUF MSSP1 Receive Buffer/Transmit Register 62

SSP1ADD MSSP1 Address Register (I2C™ Slave mode), MSSP1 Baud Rate Reload Register (I2C Master mode) 65

SSPxMSK(1) MSK7 MSK6 MSK5 MSK4 MSK3 MSK2 MSK1 MSK0 65

SSPxCON1 WCOL SSPOV SSPEN CKP SSPM3 SSPM2 SSPM1 SSPM0 62, 65

SSPxCON2 GCEN ACKSTAT ACKDT ACKEN RCEN PEN RSEN SEN 62, 65

GCEN ACKSTAT ADMSK5(2) ADMSK4(2) ADMSK3(2) ADMSK2(2) ADMSK1(2) SEN

SSPxSTAT SMP CKE D/A PSR/WUA BF 62, 65

SSP2BUF MSSP2 Receive Buffer/Transmit Register 62

SSP2ADD MSSP2 Address Register (I2C Slave mode), MSSP2 Baud Rate Reload Register (I2C Master mode) 65

Legend: — = unimplemented, read as ‘0’. Shaded cells are not used by the MSSP module in I2C™ mode.

Note 1: SSPxMSK shares the same address in SFR space as SSPxADD, but is only accessible in certain I2C™ Slave

operating modes in 7-bit Masking mode. See Section 19.4.3.4 “7-Bit Address Masking Mode” for more details.

2: Alternate bit definitions for use in I2C Slave mode operations only.

PIC18F87J50 FAMILY

20.0 ENHANCED UNIVERSAL

SYNCHRONOUS

ASYNCHRONOUS RECEIVER

TRANSMITTER (EUSART)

The Enhanced Universal Synchronous Asynchronous

Receiver Transmitter (EUSART) module is one of two

serial I/O modules. (Generically, the EUSART is also

known as a Serial Communications Interface or SCI.)

The EUSART can be configured as a full-duplex

asynchronous system that can communicate with

peripheral devices, such as CRT terminals and

personal computers. It can also be configured as a

half-duplex synchronous system that can communicate

with peripheral devices, such as A/D or D/A integrated

circuits, serial EEPROMs, etc.

The Enhanced USART module implements additional

features, including automatic baud rate detection and

calibration, automatic wake-up on Sync Break recep-

tion and 12-bit Break character transmit. These make it

ideally suited for use in Local Interconnect Network bus

(LIN bus) systems.

All members of the PIC18F87J10 family are equipped

with two independent EUSART modules, referred to as

EUSART1 and EUSART2. They can be configured in

the following modes:

• Asynchronous (full duplex) with:

- Auto-wake-up on character reception

- Auto-baud calibration

- 12-bit Break character transmission

• Synchronous – Master (half duplex) with

selectable clock polarity

• Synchronous – Slave (half duplex) with selectable

clock polarity

The pins of EUSART1 and EUSART2 are multiplexed

with the functions of PORTC (RC6/TX1/CK1 and

RC7/RX1/DT1) and PORTG (RG1/TX2/CK2 and

RG2/RX2/DT2), respectively. In order to configure

these pins as an EUSART:

• For EUSART1:

- bit SPEN (RCSTA1<7>) must be set (= 1)

- bit TRISC<7> must be set (= 1)

- bit TRISC<6> must be cleared (= 0) for

Asynchronous and Synchronous Master

modes

- bit TRISC<6> must be set (= 1) for

Synchronous Slave mode

• For EUSART2:

- bit SPEN (RCSTA2<7>) must be set (= 1)

- bit TRISG<2> must be set (= 1)

- bit TRISG<1> must be cleared (= 0) for

Asynchronous and Synchronous Master

modes

- bit TRISC<6> must be set (= 1) for

Synchronous Slave mode

The TXx/CKx I/O pins have an optional open-drain out-

put capability. By default, when this pin is used by the

EUSART as an output, it will function as a standard

push-pull CMOS output. The TXx/CKx I/O pins’

open-drain, output feature can be enabled by setting

the corresponding UxOD bit in the ODCON2 register.

For more details, see Section 10.1.4 “Open-Drain

Outputs”.

The operation of each Enhanced USART module is

controlled through three registers:

• Transmit Status and Control (TXSTAx)

• Receive Status and Control (RCSTAx)

• Baud Rate Control (BAUDCONx)

These are detailed on the following pages in

respectively.

Note: The EUSART control will automatically

reconfigure the pin from input to output as

needed.

Note: Throughout this section, references to

ated with a specific EUSART module are

referred to generically by the use of ‘x’ in

place of the specific module number.

Thus, “RCSTAx” might refer to the

Receive Status register for either

EUSART1 or EUSART2.

PIC18F87J50 FAMILY

R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R-1 R/W-0

CSRC TX9 TXEN(1) SYNC SENDB BRGH TRMT TX9D

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 CSRC: Clock Source Select bit

Asynchronous mode:

Don’t care.

Synchronous mode:

1 = Master mode (clock generated internally from BRG)

0 = Slave mode (clock from external source)

bit 6 TX9: 9-Bit Transmit Enable bit

1 = Selects 9-bit transmission

0 = Selects 8-bit transmission

bit 5 TXEN: Transmit Enable bit(1)

1 = Transmit enabled

0 = Transmit disabled

bit 4 SYNC: EUSART Mode Select bit

1 = Synchronous mode

0 = Asynchronous mode

bit 3 SENDB: Send Break Character bit

Asynchronous mode:

1 = Send Sync Break on next transmission (cleared by hardware upon completion)

0 = Sync Break transmission completed

Synchronous mode:

Don’t care.

bit 2 BRGH: High Baud Rate Select bit

Asynchronous mode:

1 = High speed

0 = Low speed

Synchronous mode:

Unused in this mode.

bit 1 TRMT: Transmit Shift Register Status bit

1 = TSR empty

0 = TSR full

bit 0 TX9D: 9th bit of Transmit Data

Can be address/data bit or a parity bit.

Note 1: SREN/CREN overrides TXEN in Sync mode.

PIC18F87J50 FAMILY

R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R-0 R-0 R-x

SPEN RX9 SREN CREN ADDEN FERR OERR RX9D

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 SPEN: Serial Port Enable bit

1 = Serial port enabled (configures RXx/DTx and TXx/CKx pins as serial port pins)

0 = Serial port disabled (held in Reset)

bit 6 RX9: 9-Bit Receive Enable bit

1 = Selects 9-bit reception

0 = Selects 8-bit reception

bit 5 SREN: Single Receive Enable bit

Asynchronous mode:

Don’t care.

Synchronous mode – Master:

1 = Enables single receive

0 = Disables single receive

This bit is cleared after reception is complete.

Synchronous mode – Slave:

Don’t care.

bit 4 CREN: Continuous Receive Enable bit

Asynchronous mode:

1 = Enables receiver

0 = Disables receiver

Synchronous mode:

1 = Enables continuous receive until enable bit CREN is cleared (CREN overrides SREN)

0 = Disables continuous receive

bit 3 ADDEN: Address Detect Enable bit

Asynchronous mode 9-Bit (RX9 = 1):

1 = Enables address detection, enables interrupt and loads the receive buffer when RSR<8> is set

0 = Disables address detection, all bytes are received and ninth bit can be used as parity bit

Asynchronous mode 9-Bit (RX9 = 0):

Don’t care.

bit 2 FERR: Framing Error bit

1 = Framing error (can be updated by reading RCREGx register and receiving next valid byte)

0 = No framing error

bit 1 OERR: Overrun Error bit

1 = Overrun error (can be cleared by clearing bit CREN)

0 = No overrun error

bit 0 RX9D: 9th bit of Received Data

This can be address/data bit or a parity bit and must be calculated by user firmware.

PIC18F87J50 FAMILY

R/W-0 R-1 R/W-0 R/W-0 R/W-0 U-0 R/W-0 R/W-0

ABDOVF RCIDL DTRXP SCKP BRG16 — WUE ABDEN

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 ABDOVF: Auto-Baud Acquisition Rollover Status bit

1 = A BRG rollover has occurred during Auto-Baud Rate Detect mode

(must be cleared in software)

0 = No BRG rollover has occurred

bit 6 RCIDL: Receive Operation Idle Status bit

1 = Receive operation is Idle

0 = Receive operation is active

bit 5 DTRXP: Data/Receive Polarity Select bit

Asynchronous mode:

1 = Receive data (RXx) is inverted (active low)

0 = Receive data (RXx) is not inverted (active high)

Synchronous mode:

1 = Data (DTx) is inverted (active low)

0 = Data (DTx) is not inverted (active high)

bit 4 SCKP: Synchronous Clock Polarity Select bit

Asynchronous mode:

1 = Idle state for transmit (TXx) is a low level

0 = Idle state for transmit (TXx) is a high level

Synchronous mode:

1 = Idle state for clock (CKx) is a high level

0 = Idle state for clock (CKx) is a low level

bit 3 BRG16: 16-Bit Baud Rate Register Enable bit

1 = 16-bit Baud Rate Generator – SPBRGHx and SPBRGx

0 = 8-bit Baud Rate Generator – SPBRGx only (Compatible mode), SPBRGHx value ignored

bit 2 Unimplemented: Read as ‘0’

bit 1 WUE: Wake-up Enable bit

Asynchronous mode:

1 = EUSART will continue to sample the RXx pin – interrupt generated on falling edge; bit cleared in

hardware on following rising edge

0 = RXx pin not monitored or rising edge detected

Synchronous mode:

Unused in this mode.

bit 0 ABDEN: Auto-Baud Detect Enable bit

Asynchronous mode:

1 = Enable baud rate measurement on the next character. Requires reception of a Sync field (55h);

cleared in hardware upon completion.

0 = Baud rate measurement disabled or completed

Synchronous mode:

Unused in this mode.

PIC18F87J50 FAMILY

20.1 Baud Rate Generator (BRG)

The BRG is a dedicated, 8-bit or 16-bit generator that

supports both the Asynchronous and Synchronous

modes of the EUSART. By default, the BRG operates

in 8-bit mode; setting the BRG16 bit (BAUDCONx<3>)

selects 16-bit mode.

The SPBRGHx:SPBRGx register pair controls the period

of a free-running timer. In Asynchronous mode, bits

BRGH (TXSTAx<2>) and BRG16 (BAUDCONx<3>) also

control the baud rate. In Synchronous mode, BRGH is

ignored. Table 20-1 shows the formula for computation of

the baud rate for different EUSART modes which only

apply in Master mode (internally generated clock).

Given the desired baud rate and FOSC, the nearest

integer value for the SPBRGHx:SPBRGx registers can

be calculated using the formulas in Table 20-1. From this,

the error in baud rate can be determined. An example

calculation is shown in Example 20-1. Typical baud rates

and error values for the various Asynchronous modes

are shown in Table 20-2. It may be advantageous to use

the high baud rate (BRGH = 1) or the 16-bit BRG to

reduce the baud rate error, or achieve a slow baud rate

for a fast oscillator frequency.

Writing a new value to the SPBRGHx:SPBRGx regis-

ters causes the BRG timer to be reset (or cleared). This

ensures the BRG does not wait for a timer overflow

before outputting the new baud rate.

20.1.1 OPERATION IN POWER-MANAGED

MODES

The device clock is used to generate the desired baud

rate. When one of the power-managed modes is

entered, the new clock source may be operating at a

different frequency. This may require an adjustment to

the value in the SPBRGx register pair.

20.1.2 SAMPLING

The data on the RXx pin (either RC7/RX1/DT1 or

RG2/RX2/DT2) is sampled three times by a majority

detect circuit to determine if a high or a low level is

present at the RXx pin.

TABLE 20-1: BAUD RATE FORMULAS

Configuration Bits BRG/EUSART Mode Baud Rate Formula

SYNC BRG16 BRGH

000 8-bit/Asynchronous FOSC/[64 (n + 1)]

001 8-bit/Asynchronous FOSC/[16 (n + 1)]

010 16-bit/Asynchronous

011 16-bit/Asynchronous

FOSC/[4 (n + 1)]10x 8-bit/Synchronous

11x 16-bit/Synchronous

Legend: x = Don’t care, n = value of SPBRGHx:SPBRGx register pair

PIC18F87J50 FAMILY

EXAMPLE 20-1: CALCULATING BAUD RATE ERROR

TABLE 20-2: REGISTERS ASSOCIATED WITH BAUD RATE GENERATOR

For a device with Fosc of 16 MHz, desired baud rate of 9600, Asynchronous mode, and 8-bit BRG:

Desired Baud Rate = FOSC/(64 ([SPBRGHx:SPBRGx] + 1))

Solving for SPBRGHx:SPBRGx:

X=((FOSC/Desired Baud Rate)/64) – 1

= ((16000000/9600)/64) – 1

= [25.042] = 25

Calculated Baud Rate = 16000000/(64 (25 + 1))

= 9615

Error = (Calculated Baud Rate – Desired Baud Rate)/Desired Baud Rate

= (9615 – 9600)/9600 = 0.16%

Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Reset Values

on Page:

TXSTAx CSRC TX9 TXEN SYNC SENDB BRGH TRMT TX9D 63

RCSTAx SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 63

BAUDCONx ABDOVF RCIDL DTRXP SCKP BRG16 —WUE ABDEN 65

SPBRGHx EUSARTx Baud Rate Generator Register High Byte 65

SPBRGx EUSARTx Baud Rate Generator Register Low Byte 65

Legend: — = unimplemented, read as ‘0’. Shaded cells are not used by the BRG.

PIC18F87J50 FAMILY

TABLE 20-3: BAUD RATES FOR ASYNCHRONOUS MODES

BAUD

RATE

(K)

SYNC = 0, BRGH = 0, BRG16 = 0

FOSC = 40.000 MHz FOSC = 20.000 MHz FOSC = 10.000 MHz FOSC = 8.000 MHz

Actual

Rate

(K)

Error

SPBRG

value

(decimal)

Actual

Rate

(K)

Error

SPBRG

value

(decimal)

Actual

Rate

(K)

Error

SPBRG

value

(decimal)

Actual

Rate

(K)

Error

SPBRG

value

(decimal)

0.3————————————

1.2 — — — 1.221 1.73 255 1.202 0.16 129 1.201 -0.16 103

2.4 2.441 1.73 255 2.404 0.16 129 2.404 0.16 64 2.403 -0.16 51

9.6 9.615 0.16 64 9.766 1.73 31 9.766 1.73 15 9.615 -0.16 12

19.2 19.531 1.73 31 19.531 1.73 15 19.531 1.73 7 — — —

57.6 56.818 -1.36 10 62.500 8.51 4 52.083 -9.58 2 — — —

115.2 125.000 8.51 4 104.167 -9.58 2 78.125 -32.18 1 — — —

BAUD

RATE

(K)

SYNC = 0, BRGH = 0, BRG16 = 0

FOSC = 4.000 MHz FOSC = 2.000 MHz FOSC = 1.000 MHz

Actual

Rate

(K)

Error

SPBRG

value

(decimal)

Actual

Rate

(K)

Error

SPBRG

value

(decimal)

Actual

Rate

(K)

Error

SPBRG

value

(decimal)

0.3 0.300 0.16 207 0.300 -0.16 103 0.300 -0.16 51

1.2 1.202 0.16 51 1.201 -0.16 25 1.201 -0.16 12

2.4 2.404 0.16 25 2.403 -0.16 12 — — —

9.6 8.929 -6.99 6 — — — — — —

19.2 20.833 8.51 2 — — — — — —

57.6 62.500 8.51 0 — — — — — —

115.2 62.500 -45.75 0 — — — — — —

BAUD

RATE

(K)

SYNC = 0, BRGH = 1, BRG16 = 0

FOSC = 40.000 MHz FOSC = 20.000 MHz FOSC = 10.000 MHz FOSC = 8.000 MHz

Actual

Rate

(K)

Error

SPBRG

value

(decimal)

Actual

Rate

(K)

Error

SPBRG

value

(decimal)

Actual

Rate

(K)

Error

SPBRG

value

(decimal)

Actual

Rate

(K)

Error

SPBRG

value

(decimal)

0.3————————————

1.2————————————

2.4 — — — — — — 2.441 1.73 255 2.403 -0.16 207

9.6 9.766 1.73 255 9.615 0.16 129 9.615 0.16 64 9615. -0.16 51

19.2 19.231 0.16 129 19.231 0.16 64 19.531 1.73 31 19.230 -0.16 25

57.6 58.140 0.94 42 56.818 -1.36 21 56.818 -1.36 10 55.555 3.55 8

115.2 113.636 -1.36 21 113.636 -1.36 10 125.000 8.51 4 — — —

BAUD

RATE

(K)

SYNC = 0, BRGH = 1, BRG16 = 0

FOSC = 4.000 MHz FOSC = 2.000 MHz FOSC = 1.000 MHz

Actual

Rate

(K)

Error

SPBRG

value

(decimal)

Actual

Rate

(K)

Error

SPBRG

value

(decimal)

Actual

Rate

(K)

Error

SPBRG

value

(decimal)

0.3 — — — — — — 0.300 -0.16 207

1.2 1.202 0.16 207 1.201 -0.16 103 1.201 -0.16 51

2.4 2.404 0.16 103 2.403 -0.16 51 2.403 -0.16 25

9.6 9.615 0.16 25 9.615 -0.16 12 — — —

19.2 19.231 0.16 12 — — — — — —

57.6 62.500 8.51 3 — — — — — —

115.2 125.000 8.51 1 — — — — — —

PIC18F87J50 FAMILY

BAUD

RATE

(K)

SYNC = 0, BRGH = 0, BRG16 = 1

FOSC = 40.000 MHz FOSC = 20.000 MHz FOSC = 10.000 MHz FOSC = 8.000 MHz

Actual

Rate

(K)

Error

SPBRG

value

(decimal)

Actual

Rate

(K)

Error

SPBRG

value

(decimal)

Actual

Rate

(K)

Error

SPBRG

value

(decimal)

Actual

Rate

(K)

Error

SPBRG

value

(decimal)

0.3 0.300 0.00 8332 0.300 0.02 4165 0.300 0.02 2082 0.300 -0.04 1665

1.2 1.200 0.02 2082 1.200 -0.03 1041 1.200 -0.03 520 1.201 -0.16 415

2.4 2.402 0.06 1040 2.399 -0.03 520 2.404 0.16 259 2.403 -0.16 207

9.6 9.615 0.16 259 9.615 0.16 129 9.615 0.16 64 9.615 -0.16 51

19.2 19.231 0.16 129 19.231 0.16 64 19.531 1.73 31 19.230 -0.16 25

57.6 58.140 0.94 42 56.818 -1.36 21 56.818 -1.36 10 55.555 3.55 8

115.2 113.636 -1.36 21 113.636 -1.36 10 125.000 8.51 4 — — —

BAUD

RATE

(K)

SYNC = 0, BRGH = 0, BRG16 = 1

FOSC = 4.000 MHz FOSC = 2.000 MHz FOSC = 1.000 MHz

Actual

Rate

(K)

Error

SPBRG

value

(decimal)

Actual

Rate

(K)

Error

SPBRG

value

(decimal)

Actual

Rate

(K)

Error

SPBRG

value

(decimal)

0.3 0.300 0.04 832 0.300 -0.16 415 0.300 -0.16 207

1.2 1.202 0.16 207 1.201 -0.16 103 1.201 -0.16 51

2.4 2.404 0.16 103 2.403 -0.16 51 2.403 -0.16 25

9.6 9.615 0.16 25 9.615 -0.16 12 — — —

19.2 19.231 0.16 12 — — — — — —

57.6 62.500 8.51 3 — — — — — —

115.2 125.000 8.51 1 — — — — — —

BAUD

RATE

(K)

SYNC = 0, BRGH = 1, BRG16 = 1 or SYNC = 1, BRG16 = 1

FOSC = 40.000 MHz FOSC = 20.000 MHz FOSC = 10.000 MHz FOSC = 8.000 MHz

Actual

Rate

(K)

Error

SPBRG

value

(decimal)

Actual

Rate

(K)

Error

SPBRG

value

(decimal)

Actual

Rate

(K)

Error

SPBRG

value

(decimal)

Actual

Rate

(K)

Error

SPBRG

value

(decimal)

0.3 0.300 0.00 33332 0.300 0.00 16665 0.300 0.00 8332 0.300 -0.01 6665

1.2 1.200 0.00 8332 1.200 0.02 4165 1.200 0.02 2082 1.200 -0.04 1665

2.4 2.400 0.02 4165 2.400 0.02 2082 2.402 0.06 1040 2.400 -0.04 832

9.6 9.606 0.06 1040 9.596 -0.03 520 9.615 0.16 259 9.615 -0.16 207

19.2 19.193 -0.03 520 19.231 0.16 259 19.231 0.16 129 19.230 -0.16 103

57.6 57.803 0.35 172 57.471 -0.22 86 58.140 0.94 42 57.142 0.79 34

115.2 114.943 -0.22 86 116.279 0.94 42 113.636 -1.36 21 117.647 -2.12 16

BAUD

RATE

(K)

SYNC = 0, BRGH = 1, BRG16 = 1 or SYNC = 1, BRG16 = 1

FOSC = 4.000 MHz FOSC = 2.000 MHz FOSC = 1.000 MHz

Actual

Rate

(K)

Error

SPBRG

value

(decimal)

Actual

Rate

(K)

Error

SPBRG

value

(decimal)

Actual

Rate

(K)

Error

SPBRG

value

(decimal)

0.3 0.300 0.01 3332 0.300 -0.04 1665 0.300 -0.04 832

1.2 1.200 0.04 832 1.201 -0.16 415 1.201 -0.16 207

2.4 2.404 0.16 415 2.403 -0.16 207 2.403 -0.16 103

9.6 9.615 0.16 103 9.615 -0.16 51 9.615 -0.16 25

19.2 19.231 0.16 51 19.230 -0.16 25 19.230 -0.16 12

57.6 58.824 2.12 16 55.555 3.55 8 — — —

115.2 111.111 -3.55 8 — — — — — —

TABLE 20-3: BAUD RATES FOR ASYNCHRONOUS MODES (CONTINUED)

PIC18F87J50 FAMILY

20.1.3 AUTO-BAUD RATE DETECT

The Enhanced USART module supports the automatic

detection and calibration of baud rate. This feature is

active only in Asynchronous mode and while the WUE

bit is clear.

The automatic baud rate measurement sequence

(Figure 20-1) begins whenever a Start bit is received

and the ABDEN bit is set. The calculation is

self-averaging.

In the Auto-Baud Rate Detect (ABD) mode, the clock to

the BRG is reversed. Rather than the BRG clocking the

incoming RXx signal, the RXx signal is timing the BRG.

In ABD mode, the internal Baud Rate Generator is

used as a counter to time the bit period of the incoming

serial byte stream.

Once the ABDEN bit is set, the state machine will clear

the BRG and look for a Start bit. The Auto-Baud Rate

Detect must receive a byte with the value 55h (ASCII

“U”, which is also the LIN bus Sync character) in order to

calculate the proper bit rate. The measurement is taken

over both a low and a high bit time in order to minimize

any effects caused by asymmetry of the incoming signal.

After a Start bit, the SPBRGx begins counting up, using

the preselected clock source on the first rising edge of

RXx. After eight bits on the RXx pin or the fifth rising

edge, an accumulated value totalling the proper BRG

period is left in the SPBRGHx:SPBRGx register pair.

Once the 5th edge is seen (this should correspond to the

Stop bit), the ABDEN bit is automatically cleared.

If a rollover of the BRG occurs (an overflow from FFFFh

to 0000h), the event is trapped by the ABDOVF status

bit (BAUDCONx<7>). It is set in hardware by BRG roll-

overs and can be set or cleared by the user in software.

ABD mode remains active after rollover events and the

ABDEN bit remains set (Figure 20-2).

While calibrating the baud rate period, the BRG regis-

ters are clocked at 1/8th the preconfigured clock rate.

Note that the BRG clock will be configured by the

BRG16 and BRGH bits. Independent of the BRG16 bit

setting, both the SPBRGx and SPBRGHx will be used

as a 16-bit counter. This allows the user to verify that

no carry occurred for 8-bit modes by checking for 00h

in the SPBRGHx register. Refer to Table 20-4 for coun-

ter clock rates to the BRG.

While the ABD sequence takes place, the EUSART

state machine is held in Idle. The RCxIF interrupt is set

once the fifth rising edge on RXx is detected. The value

in the RCREGx needs to be read to clear the RCxIF

interrupt. The contents of RCREGx should be

discarded.

TABLE 20-4: BRG COUNTER

CLOCK RATES

20.1.3.1 ABD and EUSART Transmission

Since the BRG clock is reversed during ABD acquisi-

tion, the EUSART transmitter cannot be used during

ABD. This means that whenever the ABDEN bit is set,

TXREGx cannot be written to. Users should also

ensure that ABDEN does not become set during a

transmit sequence. Failing to do this may result in

unpredictable EUSART operation.

Note 1: If the WUE bit is set with the ABDEN bit,

Auto-Baud Rate Detection will occur on

the byte following the Break character.

2: It is up to the user to determine that the

incoming character baud rate is within the

range of the selected BRG clock source.

Some combinations of oscillator frequency

and EUSART baud rates are not possible

due to bit error rates. Overall system tim-

ing and communication baud rates must

be taken into consideration when using the

Auto-Baud Rate Detection feature.

BRG16 BRGH BRG Counter Clock

00 FOSC/512

01 FOSC/128

10 FOSC/128

11 FOSC/32

Note: During the ABD sequence, SPBRGx and

SPBRGHx are both used as a 16-bit counter,

independent of BRG16 setting.

PIC18F87J50 FAMILY

FIGURE 20-1: AUTOMATIC BAUD RATE CALCULATION

FIGURE 20-2: BRG OVERFLOW SEQUENCE

BRG Value

RXx pin

ABDEN bit

RCxIF bit

Bit 0 Bit 1

(Interrupt)

Read

RCREGx

BRG Clock

Start

Auto-Cleared

Set by User

XXXXh 0000h

Edge #1

Bit 2 Bit 3

Edge #2

Bit 4 Bit 5

Edge #3

Bit 6 Bit 7

Edge #4

001Ch

Note: The ABD sequence requires the EUSART module to be configured in Asynchronous mode and WUE = 0.

SPBRGx XXXXh 1Ch

SPBRGHx XXXXh 00h

Edge #5

Stop Bit

Start Bit 0

XXXXh 0000h 0000h

FFFFh

BRG Clock

ABDEN bit

RXx pin

ABDOVF bit

BRG Value

PIC18F87J50 FAMILY

20.2 EUSART Asynchronous Mode

The Asynchronous mode of operation is selected by

clearing the SYNC bit (TXSTAx<4>). In this mode, the

EUSART uses standard Non-Return-to-Zero (NRZ)

format (one Start bit, eight or nine data bits and one Stop

bit). The most common data format is 8 bits. An on-chip

dedicated 8-bit/16-bit Baud Rate Generator can be used

to derive standard baud rate frequencies from the

oscillator.

The EUSART transmits and receives the LSb first. The

EUSART’s transmitter and receiver are functionally

independent but use the same data format and baud

rate. The Baud Rate Generator produces a clock, either

x16 or x64 of the bit shift rate, depending on the BRGH

and BRG16 bits (TXSTAx<2> and BAUDCONx<3>).

Parity is not supported by the hardware but can be

implemented in software and stored as the 9th data bit.

When operating in Asynchronous mode, the EUSART

module consists of the following important elements:

• Baud Rate Generator

• Sampling Circuit

• Asynchronous Transmitter

• Asynchronous Receiver

• Auto-Wake-up on Sync Break Character

• 12-Bit Break Character Transmit

• Auto-Baud Rate Detection

20.2.1 EUSART ASYNCHRONOUS

TRANSMITTER

The EUSART transmitter block diagram is shown in

Figure 20-3. The heart of the transmitter is the Transmit

(Serial) Shift Register (TSR). The Shift register obtains

its data from the Read/Write Transmit Buffer register,

TXREGx. The TXREGx register is loaded with data in

software. The TSR register is not loaded until the Stop

bit has been transmitted from the previous load. As

soon as the Stop bit is transmitted, the TSR is loaded

with new data from the TXREGx register (if available).

Once the TXREGx register transfers the data to the TSR

CY), the TXREGx register is

empty and the TXxIF flag bit is set. This interrupt can be

enabled or disabled by setting or clearing the interrupt

enable bit, TXxIE. TXxIF will be set regardless of the

state of TXxIE; it cannot be cleared in software. TXxIF is

also not cleared immediately upon loading TXREGx, but

becomes valid in the second instruction cycle following

the load instruction. Polling TXxIF immediately following

a load of TXREGx will return invalid results.

While TXxIF indicates the status of the TXREGx regis-

ter; another bit, TRMT (TXSTAx<1>), shows the status

of the TSR register. TRMT is a read-only bit which is set

when the TSR register is empty. No interrupt logic is

tied to this bit so the user has to poll this bit in order to

determine if the TSR register is empty.

To set up an Asynchronous Transmission:

1. Initialize the SPBRGHx:SPBRGx registers for

the appropriate baud rate. Set or clear the

BRGH and BRG16 bits, as required, to achieve

the desired baud rate.

2. Enable the asynchronous serial port by clearing

bit SYNC and setting bit, SPEN.

3. If interrupts are desired, set enable bit, TXxIE.

4. If 9-bit transmission is desired, set transmit bit

TX9. Can be used as address/data bit.

5. Enable the transmission by setting bit, TXEN,

which will also set bit, TXxIF.

6. If 9-bit transmission is selected, the ninth bit

should be loaded in bit, TX9D.

7. Load data to the TXREGx register (starts

transmission).

8. If using interrupts, ensure that the GIE and PEIE

bits in the INTCON register (INTCON<7:6>) are

set.

FIGURE 20-3: EUSART TRANSMIT BLOCK DIAGRAM

Note 1: The TSR register is not mapped in data

memory, so it is not available to the user.

2: Flag bit TXxIF is set when enable bit,

TXEN, is set.

TXxIF

TXxIE

Interrupt

TXEN Baud Rate CLK

SPBRGx

Baud Rate Generator TX9D

MSb LSb

Data Bus

TXREGx Register

TSR Register

(8) 0

TX9

TRMT SPEN

TXx pin

Pin Buffer

and Control

• • •

SPBRGHx

BRG16

PIC18F87J50 FAMILY

FIGURE 20-4: ASYNCHRONOUS TRANSMISSION

FIGURE 20-5: ASYNCHRONOUS TRANSMISSION (BACK-TO-BACK)

TABLE 20-5: REGISTERS ASSOCIATED WITH ASYNCHRONOUS TRANSMISSION

Word 1

Transmit Shift Reg

Start bit bit 0 bit 1 bit 7/8

Write to TXREGx

BRG Output

(Shift Clock)

TXx (pin)

TXxIF bit

(Transmit Buffer

Reg. Empty Flag)

TRMT bit

(Transmit Shift

Reg. Empty Flag)

1 TCY

Stop bit

Word 1

Transmit Shift Reg.

Write to TXREGx

BRG Output

(Shift Clock)

TXx (pin)

TXxIF bit

(Interrupt Reg. Flag)

TRMT bit

(Transmit Shift

Reg. Empty Flag)

Word 1 Word 2

Stop bit Start bit

Transmit Shift Reg.

Word 1 Word 2

bit 0 bit 1 bit 7/8 bit 0

Note: This timing diagram shows two consecutive transmissions.

1 TCY

Start bit

Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Reset

Values

on Page:

INTCON GIE/GIEH PEIE/GIEL TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 61

PIR1 PMPIF ADIF RC1IF TX1IF SSP1IF CCP1IF TMR2IF TMR1IF 64

PIE1 PMPIE ADIE RC1IE TX1IE SSP1IE CCP1IE TMR2IE TMR1IE 64

IPR1 PMPIP ADIP RC1IP TX1IP SSP1IP CCP1IP TMR2IP TMR1IP 64

PIR3 SSP2IF BCL2IF RC2IF TX2IF TMR4IF CCP5IF CCP4IF CCP3IF 64

PIE3 SSP2IE BCL2IE RC2IE TX2IE TMR4IE CCP5IE CCP4IE CCP3IE 64

IPR3 SSP2IP BCL2IP RC2IP TX2IP TMR4IP CCP5IP CCP4IP CCP3IP 64

RCSTAx SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 63

TXREGx EUSARTx Transmit Register 63

TXSTAx CSRC TX9 TXEN SYNC SENDB BRGH TRMT TX9D 63

BAUDCONx ABDOVF RCIDL DTRXP SCKP BRG16 —WUE ABDEN 65

SPBRGHx EUSARTx Baud Rate Generator Register High Byte 65

SPBRGx EUSARTx Baud Rate Generator Register Low Byte 65

ODCON2 — — — — U2OD U1OD 62

Legend: — = unimplemented locations read as ‘0’. Shaded cells are not used for asynchronous transmission.

PIC18F87J50 FAMILY

20.2.2 EUSART ASYNCHRONOUS

RECEIVER

The receiver block diagram is shown in Figure 20-6.

The data is received on the RXx pin and drives the data

recovery block. The data recovery block is actually a

high-speed shifter operating at x16 times the baud rate,

whereas the main receive serial shifter operates at the

bit rate or at FOSC. This mode would typically be used

in RS-232 systems.

To set up an Asynchronous Reception:

1. Initialize the SPBRGHx:SPBRGx registers for

the appropriate baud rate. Set or clear the

BRGH and BRG16 bits, as required, to achieve

the desired baud rate.

2. Enable the asynchronous serial port by clearing

bit, SYNC, and setting bit, SPEN.

3. If interrupts are desired, set enable bit, RCxIE.

4. If 9-bit reception is desired, set bit, RX9.

5. Enable the reception by setting bit, CREN.

6. Flag bit, RCxIF, will be set when reception is

complete and an interrupt will be generated if

enable bit, RCxIE, was set.

7. Read the RCSTAx register to get the 9th bit (if

enabled) and determine if any error occurred

during reception.

8. Read the 8-bit received data by reading the

RCREGx register.

9. If any error occurred, clear the error by clearing

enable bit, CREN.

10. If using interrupts, ensure that the GIE and PEIE

bits in the INTCON register (INTCON<7:6>) are

set.

20.2.3 SETTING UP 9-BIT MODE WITH

ADDRESS DETECT

This mode would typically be used in RS-485 systems.

To set up an Asynchronous Reception with Address

Detect Enable:

1. Initialize the SPBRGHx:SPBRGx registers for

the appropriate baud rate. Set or clear the

BRGH and BRG16 bits, as required, to achieve

the desired baud rate.

2. Enable the asynchronous serial port by clearing

the SYNC bit and setting the SPEN bit.

3. If interrupts are required, set the RCEN bit and

select the desired priority level with the RCxIP bit.

4. Set the RX9 bit to enable 9-bit reception.

5. Set the ADDEN bit to enable address detect.

6. Enable reception by setting the CREN bit.

7. The RCxIF bit will be set when reception is

complete. The interrupt will be Acknowledged if

the RCxIE and GIE bits are set.

8. Read the RCSTAx register to determine if any

error occurred during reception, as well as read

bit 9 of data (if applicable).

9. Read RCREGx to determine if the device is

being addressed.

10. If any error occurred, clear the CREN bit.

11. If the device has been addressed, clear the

ADDEN bit to allow all received data into the

receive buffer and interrupt the CPU.

FIGURE 20-6: EUSARTx RECEIVE BLOCK DIAGRAM

x64 Baud Rate CLK

Baud Rate Generator

RXx

Pin Buffer

and Control

SPEN

Data

Recovery

CREN OERR FERR

RSR Register

MSb LSb

RX9D RCREGx Register

FIFO

Interrupt RCxIF

RCxIE

Data Bus

÷ 64

÷ 16

Stop Start

(8) 7 1 0

RX9

• • •

SPBRGxSPBRGHx

BRG16

÷ 4

PIC18F87J50 FAMILY

FIGURE 20-7: ASYNCHRONOUS RECEPTION

TABLE 20-6: REGISTERS ASSOCIATED WITH ASYNCHRONOUS RECEPTION

20.2.4 AUTO-WAKE-UP ON SYNC BREAK

CHARACTER

During Sleep mode, all clocks to the EUSART are

suspended. Because of this, the Baud Rate Generator

is inactive and a proper byte reception cannot be per-

formed. The auto-wake-up feature allows the controller

to wake-up due to activity on the RXx/DTx line while the

EUSART is operating in Asynchronous mode.

The auto-wake-up feature is enabled by setting the

WUE bit (BAUDCONx<1>). Once set, the typical

receive sequence on RXx/DTx is disabled and the

EUSART remains in an Idle state, monitoring for a

wake-up event independent of the CPU mode. A

wake-up event consists of a high-to-low transition on

the RXx/DTx line. (This coincides with the start of a

Sync Break or a Wake-up Signal character for the LIN

protocol.)

Following a wake-up event, the module generates an

RCxIF interrupt. The interrupt is generated synchro-

nously to the Q clocks in normal operating modes

(Figure 20-8) and asynchronously if the device is in

Sleep mode (Figure 20-9). The interrupt condition is

cleared by reading the RCREGx register.

The WUE bit is automatically cleared once a

low-to-high transition is observed on the RXx line

following the wake-up event. At this point, the EUSART

module is in Idle mode and returns to normal operation.

This signals to the user that the Sync Break event is

over.

Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Reset

Values

on Page:

INTCON GIE/GIEH PEIE/GIEL TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 61

PIR1 PMPIF ADIF RC1IF TX1IF SSP1IF CCP1IF TMR2IF TMR1IF 64

PIE1 PMPIE ADIE RC1IE TX1IE SSP1IE CCP1IE TMR2IE TMR1IE 64

IPR1 PMPIP ADIP RC1IP TX1IP SSP1IP CCP1IP TMR2IP TMR1IP 64

PIR3 SSP2IF BCL2IF RC2IF TX2IF TMR4IF CCP5IF CCP4IF CCP3IF 64

PIE3 SSP2IE BCL2IE RC2IE TX2IE TMR4IE CCP5IE CCP4IE CCP3IE 64

IPR3 SSP2IP BCL2IP RC2IP TX2IP TMR4IP CCP5IP CCP4IP CCP3IP 64

RCSTAx SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 63

RCREGx EUSARTx Receive Register 63

TXSTAx CSRC TX9 TXEN SYNC SENDB BRGH TRMT TX9D 63

BAUDCONx ABDOVF RCIDL DTRXP SCKP BRG16 — WUE ABDEN 65

SPBRGHx EUSARTx Baud Rate Generator Register High Byte 65

SPBRGx EUSARTx Baud Rate Generator Register Low Byte 65

Legend: — = unimplemented locations read as ‘0’. Shaded cells are not used for asynchronous reception.

Start

bit bit 7/8

bit 1bit 0 bit 7/8 bit 0

Stop

bit

Start

bit

Start

bit

bit 7/8 Stop

bit

RXx (pin)

Rcv Buffer Reg

Rcv Shift Reg

Read Rcv

Buffer Reg

RCREGx

RCxIF

(Interrupt Flag)

OERR bit

CREN

Word 1

RCREGx

Word 2

RCREGx

Stop

bit

Note: This timing diagram shows three words appearing on the RXx input. The RCREGx (Receive Buffer) is read after the third word

causing the OERR (Overrun) bit to be set.

PIC18F87J50 FAMILY

20.2.4.1 Special Considerations Using

Auto-Wake-up

Since auto-wake-up functions by sensing rising edge

transitions on RXx/DTx, information with any state

changes before the Stop bit may signal a false

End-of-Character (EOC) and cause data or framing

errors. To work properly, therefore, the initial character

in the transmission must be all ‘0’s. This can be 00h (8

bytes) for standard RS-232 devices or 000h (12 bits) for

LIN bus.

Oscillator start-up time must also be considered,

especially in applications using oscillators with longer

start-up intervals (i.e., HS or HSPLL mode). The Sync

Break (or Wake-up Signal) character must be of

sufficient length and be followed by a sufficient interval

to allow enough time for the selected oscillator to start

and provide proper initialization of the EUSART.

20.2.4.2 Special Considerations Using

the WUE Bit

The timing of WUE and RCxIF events may cause some

confusion when it comes to determining the validity of

received data. As noted, setting the WUE bit places the

EUSART in an Idle mode. The wake-up event causes a

receive interrupt by setting the RCxIF bit. The WUE bit

is cleared after this when a rising edge is seen on

RXx/DTx. The interrupt condition is then cleared by

reading the RCREGx register. Ordinarily, the data in

RCREGx will be dummy data and should be discarded.

The fact that the WUE bit has been cleared (or is still

set) and the RCxIF flag is set should not be used as an

indicator of the integrity of the data in RCREGx. Users

should consider implementing a parallel method in

firmware to verify received data integrity.

To assure that no actual data is lost, check the RCIDL

bit to verify that a receive operation is not in process. If

a receive operation is not occurring, the WUE bit may

then be set just prior to entering the Sleep mode.

FIGURE 20-8: AUTO-WAKE-UP BIT (WUE) TIMINGS DURING NORMAL OPERATION

FIGURE 20-9: AUTO-WAKE-UP BIT (WUE) TIMINGS DURING SLEEP

Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4

OSC1

WUE bit(1)

RXx/DTx Line

RCxIF

Note 1: The EUSART remains in Idle while the WUE bit is set.

Bit set by user

Cleared due to user read of RCREGx

Auto-Cleared

Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4

OSC1

WUE bit(2)

RXx/DTx Line

RCxIF

Cleared due to user read of RCREGx

SLEEP Command Executed

Note 1: If the wake-up event requires long oscillator warm-up time, the auto-clear of the WUE bit can occur before the oscillator is ready. This

sequence should not depend on the presence of Q clocks.

2: The EUSART remains in Idle while the WUE bit is set.

Sleep Ends

Note 1

Auto-Cleared

Bit set by user

PIC18F87J50 FAMILY

20.2.5 BREAK CHARACTER SEQUENCE

The EUSART module has the capability of sending the

special Break character sequences that are required by

the LIN bus standard. The Break character transmit

consists of a Start bit, followed by twelve ‘0’ bits and a

Stop bit. The Frame Break character is sent whenever

the SENDB and TXEN bits (TXSTAx<3> and

TXSTAx<5>) are set while the Transmit Shift Register

is loaded with data. Note that the value of data written

to TXREGx will be ignored and all ‘0’s will be

transmitted.

The SENDB bit is automatically reset by hardware after

the corresponding Stop bit is sent. This allows the user

to preload the transmit FIFO with the next transmit byte

following the Break character (typically, the Sync

character in the LIN specification).

Note that the data value written to the TXREGx for the

Break character is ignored. The write simply serves the

purpose of initiating the proper sequence.

The TRMT bit indicates when the transmit operation is

active or Idle, just as it does during normal transmis-

sion. See Figure 20-10 for the timing of the Break

character sequence.

20.2.5.1 Break and Sync Transmit Sequence

The following sequence will send a message frame

header made up of a Break, followed by an Auto-Baud

Sync byte. This sequence is typical of a LIN bus

master.

1. Configure the EUSART for the desired mode.

2. Set the TXEN and SENDB bits to set up the

Break character.

3. Load the TXREGx with a dummy character to

initiate transmission (the value is ignored).

4. Write ‘55h’ to TXREGx to load the Sync

character into the transmit FIFO buffer.

5. After the Break has been sent, the SENDB bit is

reset by hardware. The Sync character now

transmits in the preconfigured mode.

When the TXREGx becomes empty, as indicated by

the TXxIF, the next data byte can be written to

TXREGx.

20.2.6 RECEIVING A BREAK CHARACTER

The Enhanced USART module can receive a Break

character in two ways.

The first method forces configuration of the baud rate

at a frequency of 9/13 the typical speed. This allows for

the Stop bit transition to be at the correct sampling

location (13 bits for Break versus Start bit and 8 data

bits for typical data).

The second method uses the auto-wake-up feature

described in Section 20.2.4 “Auto-Wake-up on Sync

Break Character”. By enabling this feature, the

EUSART will sample the next two transitions on

RXx/DTx, cause an RCxIF interrupt and receive the

next data byte followed by another interrupt.

Note that following a Break character, the user will

typically want to enable the Auto-Baud Rate Detect

feature. For both methods, the user can set the ABDEN

bit once the TXxIF interrupt is observed.

FIGURE 20-10: SEND BREAK CHARACTER SEQUENCE

Write to TXREGx

BRG Output

(Shift Clock)

Start Bit Bit 0 Bit 1 Bit 11 Stop Bit

Break

TXxIF bit

(Transmit Buffer

Reg. Empty Flag)

TXx (pin)

TRMT bit

(Transmit Shift

Reg. Empty Flag)

SENDB bit

(Transmit Shift

Reg. Empty Flag)

SENDB sampled here Auto-Cleared

Dummy Write

PIC18F87J50 FAMILY

20.3 EUSART Synchronous

Master Mode

The Synchronous Master mode is entered by setting

the CSRC bit (TXSTAx<7>). In this mode, the data is

transmitted in a half-duplex manner (i.e., transmission

and reception do not occur at the same time). When

transmitting data, the reception is inhibited and vice

versa. Synchronous mode is entered by setting bit,

SYNC (TXSTAx<4>). In addition, enable bit, SPEN

(RCSTAx<7>), is set in order to configure the TXx and

RXx pins to CKx (clock) and DTx (data) lines,

respectively.

The Master mode indicates that the processor trans-

mits the master clock on the CKx line. Clock polarity is

selected with the SCKP bit (BAUDCONx<4>). Setting

SCKP sets the Idle state on CKx as high, while clearing

the bit sets the Idle state as low. This option is provided

to support Microwire devices with this module.

20.3.1 EUSART SYNCHRONOUS MASTER

TRANSMISSION

The EUSART transmitter block diagram is shown in

Figure 20-3. The heart of the transmitter is the Transmit

(Serial) Shift Register (TSR). The Shift register obtains

its data from the Read/Write Transmit Buffer register,

TXREGx. The TXREGx register is loaded with data in

software. The TSR register is not loaded until the last

bit has been transmitted from the previous load. As

soon as the last bit is transmitted, the TSR is loaded

with new data from the TXREGx (if available).

Once the TXREGx register transfers the data to the

TSR register (occurs in one TCY), the TXREGx is empty

and the TXxIF flag bit is set. The interrupt can be

enabled or disabled by setting or clearing the interrupt

enable bit, TXxIE. TXxIF is set regardless of the state

of enable bit, TXxIE; it cannot be cleared in software. It

will reset only when new data is loaded into the

TXREGx register.

While flag bit, TXxIF, indicates the status of the TXREGx

status of the TSR register. TRMT is a read-only bit which

is set when the TSR is empty. No interrupt logic is tied to

this bit, so the user must poll this bit in order to determine

if the TSR register is empty. The TSR is not mapped in

data memory so it is not available to the user.

To set up a Synchronous Master Transmission:

1. Initialize the SPBRGHx:SPBRGx registers for the

appropriate baud rate. Set or clear the BRG16

bit, as required, to achieve the desired baud rate.

2. Enable the synchronous master serial port by

setting bits, SYNC, SPEN and CSRC.

3. If interrupts are desired, set enable bit, TXxIE.

4. If 9-bit transmission is desired, set bit, TX9.

5. Enable the transmission by setting bit, TXEN.

6. If 9-bit transmission is selected, the ninth bit

should be loaded in bit, TX9D.

7. Start transmission by loading data to the

TXREGx register.

8. If using interrupts, ensure that the GIE and PEIE

bits in the INTCON register (INTCON<7:6>) are

set.

FIGURE 20-11: SYNCHRONOUS TRANSMISSION

bit 0 bit 1 bit 7

Word 1

Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q3 Q4 Q1 Q2 Q3 Q4 Q1Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4

bit 2 bit 0 bit 1 bit 7RC7/RX1/DT1

RC6/TX1/CK1 pin

Write to

TXREG1 Reg

TX1IF bit

(Interrupt Flag)

TXEN bit ‘1’ ‘1’

Word 2

TRMT bit

Write Word 1 Write Word 2

Note: Sync Master mode, SPBRGx = 0, continuous transmission of two 8-bit words. This example is equally applicable to EUSART2

(RG1/TX2/CK2 and RG2/RX2/DT2).

RC6/TX1/CK1 pin

(SCKP = 0)

(SCKP = 1)

PIC18F87J50 FAMILY

FIGURE 20-12: SYNCHRONOUS TRANSMISSION (THROUGH TXEN)

TABLE 20-7: REGISTERS ASSOCIATED WITH SYNCHRONOUS MASTER TRANSMISSION

RC7/RX1/DT1 pin

RC6/TX1/CK1 pin

Write to

TXREG1 reg

TX1IF bit

TRMT bit

bit 0 bit 1 bit 2 bit 6 bit 7

TXEN bit

Note: This example is equally applicable to EUSART2 (RG1/TX2/CK2 and RG2/RX2/DT2).

Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Reset

Values

on Page:

INTCON GIE/GIEH PEIE/GIEL TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 61

PIR1 PMPIF ADIF RC1IF TX1IF SSP1IF CCP1IF TMR2IF TMR1IF 64

PIE1 PMPIE ADIE RC1IE TX1IE SSP1IE CCP1IE TMR2IE TMR1IE 64

IPR1 PMPIP ADIP RC1IP TX1IP SSP1IP CCP1IP TMR2IP TMR1IP 64

PIR3 SSP2IF BCL2IF RC2IF TX2IF TMR4IF CCP5IF CCP4IF CCP3IF 64

PIE3 SSP2IE BCL2IE RC2IE TX2IE TMR4IE CCP5IE CCP4IE CCP3IE 64

IPR3 SSP2IP BCL2IP RC2IP TX2IP TMR4IP CCP5IP CCP4IP CCP3IP 64

RCSTAx SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 63

TXREGx EUSARTx Transmit Register 63

TXSTAx CSRC TX9 TXEN SYNC SENDB BRGH TRMT TX9D 63

BAUDCONx ABDOVF RCIDL DTRXP SCKP BRG16 —WUE ABDEN 65

SPBRGHx EUSARTx Baud Rate Generator Register High Byte 65

SPBRGx EUSARTx Baud Rate Generator Register Low Byte 65

ODCON2 — — — — U2OD U1OD 62

Legend: — = unimplemented, read as ‘0’. Shaded cells are not used for synchronous master transmission.

PIC18F87J50 FAMILY

20.3.2 EUSART SYNCHRONOUS

MASTER RECEPTION

Once Synchronous mode is selected, reception is

enabled by setting either the Single Receive Enable bit,

SREN (RCSTAx<5>) or the Continuous Receive

Enable bit, CREN (RCSTAx<4>). Data is sampled on

the RXx pin on the falling edge of the clock.

If enable bit, SREN, is set, only a single word is

received. If enable bit, CREN, is set, the reception is

continuous until CREN is cleared. If both bits are set,

then CREN takes precedence.

To set up a Synchronous Master Reception:

1. Initialize the SPBRGHx:SPBRGx registers for the

appropriate baud rate. Set or clear the BRG16

bit, as required, to achieve the desired baud rate.

2. Enable the synchronous master serial port by

setting bits, SYNC, SPEN and CSRC.

3. Ensure bits, CREN and SREN, are clear.

4. If interrupts are desired, set enable bit, RCxIE.

5. If 9-bit reception is desired, set bit, RX9.

6. If a single reception is required, set bit, SREN.

For continuous reception, set bit, CREN.

7. Interrupt flag bit, RCxIF, will be set when recep-

tion is complete and an interrupt will be generated

if the enable bit, RCxIE, was set.

8. Read the RCSTAx register to get the 9th bit (if

enabled) and determine if any error occurred

during reception.

9. Read the 8-bit received data by reading the

RCREGx register.

10. If any error occurred, clear the error by clearing

bit, CREN.

11. If using interrupts, ensure that the GIE and PEIE bits

in the INTCON register (INTCON<7:6>) are set.

FIGURE 20-13: SYNCHRONOUS RECEPTION (MASTER MODE, SREN)

CREN bit

RC7/RX1/DT1

RC6/TX1/CK1 pin

Write to

bit SREN

SREN bit

RC1IF bit

(Interrupt)

Read

RCREG1

Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4Q2 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4

‘

’

bit 0 bit 1 bit 2 bit 3 bit 4 bit 5 bit 6 bit 7

‘

’

Q1 Q2 Q3 Q4

Note: Timing diagram demonstrates Sync Master mode with bit SREN = 1 and bit BRGH = 0. This example is equally applicable to EUSART2

(RG1/TX2/CK2 and RG2/RX2/DT2).

RC6/TX1/CK1 pin

(SCKP = 0)

(SCKP = 1)

PIC18F87J50 FAMILY

TABLE 20-8: REGISTERS ASSOCIATED WITH SYNCHRONOUS MASTER RECEPTION

20.4 EUSART Synchronous

Slave Mode

Synchronous Slave mode is entered by clearing bit,

CSRC (TXSTAx<7>). This mode differs from the

Synchronous Master mode in that the shift clock is sup-

plied externally at the CKx pin (instead of being supplied

internally in Master mode). This allows the device to

transfer or receive data while in any low-power mode.

20.4.1 EUSART SYNCHRONOUS

SLAVE TRANSMISSION

The operation of the Synchronous Master and Slave

modes is identical, except in the case of Sleep mode.

If two words are written to the TXREGx and then the

SLEEP instruction is executed, the following will occur:

a) The first word will immediately transfer to the

TSR register and transmit.

b) The second word will remain in the TXREGx

c) Flag bit, TXxIF, will not be set.

d) When the first word has been shifted out of TSR,

the TXREGx register will transfer the second

word to the TSR and flag bit, TXxIF, will now be

set.

e) If enable bit, TXxIE, is set, the interrupt will wake

the chip from Sleep. If the global interrupt is

enabled, the program will branch to the interrupt

vector.

To set up a Synchronous Slave Transmission:

1. Enable the synchronous slave serial port by

setting bits, SYNC and SPEN, and clearing bit,

CSRC.

2. Clear bits, CREN and SREN.

3. If interrupts are desired, set enable bit, TXxIE.

4. If 9-bit transmission is desired, set bit, TX9.

5. Enable the transmission by setting enable bit,

TXEN.

6. If 9-bit transmission is selected, the ninth bit

should be loaded in bit, TX9D.

7. Start transmission by loading data to the

TXREGx register.

8. If using interrupts, ensure that the GIE and PEIE

bits in the INTCON register (INTCON<7:6>) are

set.

Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Reset Values

on Page:

INTCON GIE/GIEH PEIE/GIEL TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 61

PIR1 PMPIF ADIF RC1IF TX1IF SSP1IF CCP1IF TMR2IF TMR1IF 64

PIE1 PMPIE ADIE RC1IE TX1IE SSP1IE CCP1IE TMR2IE TMR1IE 64

IPR1 PMPIP ADIP RC1IP TX1IP SSP1IP CCP1IP TMR2IP TMR1IP 64

PIR3 SSP2IF BCL2IF RC2IF TX2IF TMR4IF CCP5IF CCP4IF CCP3IF 64

PIE3 SSP2IE BCL2IE RC2IE TX2IE TMR4IE CCP5IE CCP4IE CCP3IE 64

IPR3 SSP2IP BCL2IP RC2IP TX2IP TMR4IP CCP5IP CCP4IP CCP3IP 64

RCSTAx SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 63

RCREGx EUSARTx Receive Register 63

TXSTAx CSRC TX9 TXEN SYNC SENDB BRGH TRMT TX9D 63

BAUDCONx ABDOVF RCIDL DTRXP SCKP BRG16 —WUE ABDEN 65

SPBRGHx EUSARTx Baud Rate Generator Register High Byte 65

SPBRGx EUSARTx Baud Rate Generator Register Low Byte 65

ODCON2 — — — — U2OD U1OD 62

Legend: — = unimplemented, read as ‘0’. Shaded cells are not used for synchronous master reception.

PIC18F87J50 FAMILY

TABLE 20-9: REGISTERS ASSOCIATED WITH SYNCHRONOUS SLAVE TRANSMISSION

20.4.2 EUSART SYNCHRONOUS SLAVE

RECEPTION

The operation of the Synchronous Master and Slave

modes is identical, except in the case of Sleep, or any

Idle mode and bit, SREN, which is a “don’t care” in

Slave mode.

If receive is enabled by setting the CREN bit prior to

entering Sleep or any Idle mode, then a word may be

received while in this low-power mode. Once the word

is received, the RSR register will transfer the data to the

RCREGx register. If the RCxIE enable bit is set, the

interrupt generated will wake the chip from the

low-power mode. If the global interrupt is enabled, the

program will branch to the interrupt vector.

To set up a Synchronous Slave Reception:

1. Enable the synchronous master serial port by

setting bits, SYNC and SPEN, and clearing bit,

CSRC.

2. If interrupts are desired, set enable bit, RCxIE.

3. If 9-bit reception is desired, set bit, RX9.

4. To enable reception, set enable bit, CREN.

5. Flag bit, RCxIF, will be set when reception is

complete. An interrupt will be generated if

enable bit, RCxIE, was set.

6. Read the RCSTAx register to get the 9th bit (if

enabled) and determine if any error occurred

during reception.

7. Read the 8-bit received data by reading the

RCREGx register.

8. If any error occurred, clear the error by clearing

bit, CREN.

9. If using interrupts, ensure that the GIE and PEIE

bits in the INTCON register (INTCON<7:6>) are

set.

Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Reset

Values

on Page:

INTCON GIE/GIEH PEIE/GIEL TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 61

PIR1 PMPIF ADIF RC1IF TX1IF SSP1IF CCP1IF TMR2IF TMR1IF 64

PIE1 PMPIE ADIE RC1IE TX1IE SSP1IE CCP1IE TMR2IE TMR1IE 64

IPR1 PMPIP ADIP RC1IP TX1IP SSP1IP CCP1IP TMR2IP TMR1IP 64

PIR3 SSP2IF BCL2IF RC2IF TX2IF TMR4IF CCP5IF CCP4IF CCP3IF 64

PIE3 SSP2IE BCL2IE RC2IE TX2IE TMR4IE CCP5IE CCP4IE CCP3IE 64

IPR3 SSP2IP BCL2IP RC2IP TX2IP TMR4IP CCP5IP CCP4IP CCP3IP 64

RCSTAx SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 63

TXREGx EUSARTx Transmit Register 63

TXSTAx CSRC TX9 TXEN SYNC SENDB BRGH TRMT TX9D 63

BAUDCONx ABDOVF RCIDL DTRXP SCKP BRG16 —WUE ABDEN 65

SPBRGHx EUSARTx Baud Rate Generator Register High Byte 65

SPBRGx EUSARTx Baud Rate Generator Register Low Byte 65

Legend: — = unimplemented, read as ‘0’. Shaded cells are not used for synchronous slave transmission.

PIC18F87J50 FAMILY

TABLE 20-10: REGISTERS ASSOCIATED WITH SYNCHRONOUS SLAVE RECEPTION

Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Reset

Values

on Page:

INTCON GIE/GIEH PEIE/GIEL TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 61

PIR1 PMPIF ADIF RC1IF TX1IF SSP1IF CCP1IF TMR2IF TMR1IF 64

PIE1 PMPIE ADIE RC1IE TX1IE SSP1IE CCP1IE TMR2IE TMR1IE 64

IPR1 PMPIP ADIP RC1IP TX1IP SSP1IP CCP1IP TMR2IP TMR1IP 64

PIR3 SSP2IF BCL2IF RC2IF TX2IF TMR4IF CCP5IF CCP4IF CCP3IF 64

PIE3 SSP2IE BCL2IE RC2IE TX2IE TMR4IE CCP5IE CCP4IE CCP3IE 64

IPR3 SSP2IP BCL2IP RC2IP TX2IP TMR4IP CCP5IP CCP4IP CCP3IP 64

RCSTAx SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 63

RCREGx EUSARTx Receive Register 63

TXSTAx CSRC TX9 TXEN SYNC SENDB BRGH TRMT TX9D 63

BAUDCONx ABDOVF RCIDL DTRXP SCKP BRG16 —WUE ABDEN 65

SPBRGHx EUSARTx Baud Rate Generator Register High Byte 65

SPBRGx EUSARTx Baud Rate Generator Register Low Byte 65

Legend: — = unimplemented, read as ‘0’. Shaded cells are not used for synchronous slave reception.

PIC18F87J50 FAMILY

21.0 10-BIT ANALOG-TO-DIGITAL

CONVERTER (A/D) MODULE

The Analog-to-Digital (A/D) Converter module has

8 inputs for the 64-pin devices and 12 for the 80-pin

devices. This module allows conversion of an analog

input signal to a corresponding 10-bit digital number.

The module has six registers:

• A/D Control Register 0 (ADCON0)

• A/D Control Register 1 (ADCON1)

• A/D Port Configuration Register 2 (ANCON0)

• A/D Port Configuration Register 1 (ANCON1)

• A/D Result Registers (ADRESH and ADRESL)

The ADCON0 register, shown in Register 21-1, controls

the operation of the A/D module. The ADCON1 register,

shown in Register 21-2, configures the A/D clock source,

programmed acquisition time and justification.

The ANCON0 and ANCON1 registers, shown in

functions of the port pins.

R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

VCFG1 VCFG0 CHS3 CHS2 CHS1 CHS0 GO/DONE ADON

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7-6 VCFG1: Voltage Reference Configuration bit (VREF- source)

1 = VREF- (AN2)

0 = AVSS

bit VCFG0: Voltage Reference Configuration bit (VREF+ source)

1 = VREF+ (AN3)

0 = AVDD

bit 5-2 CHS3:CHS0: Analog Channel Select bits

0000 = Channel 00 (AN0)

0001 = Channel 01 (AN1)

0010 = Channel 02 (AN2)

0011 = Channel 03 (AN3)

0100 = Channel 04 (AN4)

0101 = Unused

0110 = Unused

0111 = Channel 07 (AN7)

1000 = Unused

1001 = Unused

1010 = Channel 10 (AN10)

1011 = Channel 11 (AN11)

1100 = Channel 12 (AN12)(2,3)

1101 = Channel 13 (AN13)(2,3)

1110 = Channel 14 (AN14)(2,3)

1111 =Channel 15 (AN15)(2,3)

bit 1 GO/DONE: A/D Conversion Status bit

When ADON = 1:

1 = A/D conversion in progress

0 = A/D Idle

bit 0 ADON: A/D On bit

1 = A/D Converter module is enabled

0 = A/D Converter module is disabled

Note 1: Default (legacy) SFR at this address, available when WDTCON<4> = 0.

2: These channels are not implemented on 64-pin devices.

3: Performing a conversion on unimplemented channels will return random values.

PIC18F87J50 FAMILY

R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

ADFM ADCAL ACQT2 ACQT1 ACQT0 ADCS2 ADCS1 ADCS0

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 ADFM: A/D Result Format Select bit

1 = Right justified

0 = Left justified

bit 6 ADCAL: A/D Calibration bit

1 = Calibration is performed on next A/D conversion

0 = Normal A/D Converter operation (no conversion is performed)

bit 5-3 ACQT2:ACQT0: A/D Acquisition Time Select bits

111 = 20 T

110 = 16 TAD

101 = 12 TAD

100 = 8 TAD

011 = 6 TAD

010 = 4 TAD

001 = 2 TAD

000 = 0 TAD(2)

bit 2-0 ADCS2:ADCS0: A/D Conversion Clock Select bits

111 = FRC (clock derived from A/D RC oscillator)(2)

110 = FOSC/64

101 = FOSC/16

100 = FOSC/4

011 = FRC (clock derived from A/D RC oscillator)(2)

010 = FOSC/32

001 = FOSC/8

000 = FOSC/2

Note 1: Default (legacy) SFR at this address, available when WDTCON<4> = 0.

2: If the A/D FRC clock source is selected, a delay of one TCY (instruction cycle) is added before the A/D

clock starts. This allows the SLEEP instruction to be executed before starting a conversion.

PIC18F87J50 FAMILY

The ANCON0 and ANCON1 registers are used to

configure the operation of the I/O pin associated with

each analog channel. Setting any one of the PCFG bits

configures the corresponding pin to operate as a digital

only I/O. Clearing a bit configures the pin to operate as

an analog input for either the A/D Converter or the com-

parator module; all digital peripherals are disabled, and

digital inputs read as ‘0’. As a rule, I/O pins that are

multiplexed with analog inputs default to analog

operation on device Resets.

ANCON0 and ANCON1 are shared address SFRs, and

use the same addresses as the ADCON1 and

ADCON0 registers. The ANCON registers are

accessed by setting the ADSHR bit (WDTCON<4>).

See Section 5.3.5.1 “Shared Address SFRs” for

more information.

R/W-0 U-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

PCFG7 —— PCFG4 PCFG3 PCFG2 PCFG1 PCFG0

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 PCFG7: Analog Port Configuration bits (AN7)

1 = Pin configured as a digital port

0 = Pin configured as an analog channel - digital input disabled and reads ‘0’

bit 6-5 Unimplemented: Read as ‘0’

bit 4-0 PCFG4:PCFG0: Analog Port Configuration bits (AN4-AN0)

1 = Pin configured as a digital port

0 = Pin configured as an analog channel - digital input disabled and reads ‘0’

R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 U-0 U-0

PCFG15 PCFG14 PCFG13 PCFG12 PCFG11 PCFG10 — —

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7-2 PCFG15:PCFG10: Analog Port Configuration bits (AN15-AN10)(1)

1 = Pin configured as a digital port

0 = Pin configured as an analog channel - digital input disabled and reads ‘0’

bit 1-0 Unimplemented: Read as ‘0’

Note 1: AN15 through AN12 are available only in 80-pin devices.

PIC18F87J50 FAMILY

The analog reference voltage is software selectable to

either the device’s positive and negative supply voltage

(AVDD and AVSS), or the voltage level on the

RA3/AN3/VREF+ and RA2/AN2/VREF- pins.

The A/D Converter has a unique feature of being able

to operate while the device is in Sleep mode. To

operate in Sleep, the A/D conversion clock must be

derived from the A/D’s internal RC oscillator.

The output of the sample and hold is the input into the

Converter, which generates the result via successive

approximation.

Each port pin associated with the A/D Converter can be

configured as an analog input or as a digital I/O. The

ADRESH and ADRESL registers contain the result of

the A/D conversion. When the A/D conversion is com-

plete, the result is loaded into the ADRESH:ADRESL

cleared and A/D Interrupt Flag bit, ADIF, is set.

A device Reset forces all registers to their Reset state.

This forces the A/D module to be turned off and any

conversion in progress is aborted. The value in the

ADRESH:ADRESL register pair is not modified for a

Power-on Reset. These registers will contain unknown

data after a Power-on Reset.

The block diagram of the A/D module is shown in

Figure 21-1.

FIGURE 21-1: A/D BLOCK DIAGRAM

(Input Voltage)

VAIN

VREF+

Reference

Voltage

VDD(2)

VCFG1:VCFG0

CHS3:CHS0

AN7

AN4

AN3

AN2

AN1

AN0

0111

0100

0011

0010

0001

0000

10-Bit

A/D

VREF-

VSS(2)

Converter

AN15(1)

AN14(1)

AN13(1)

AN12(1)

AN11

AN10

1111

1110

1101

1100

1011

1010

Note 1: Channels AN15 through AN12 are not available on 64-pin devices.

2: I/O pins have diode protection to VDD and VSS.

PIC18F87J50 FAMILY

After the A/D module has been configured as desired,

the selected channel must be acquired before the

conversion is started. The analog input channels must

have their corresponding TRIS bits selected as an

input. To determine acquisition time, see Section 21.1

“A/D Acquisition Requirements”. After this acquisi-

tion time has elapsed, the A/D conversion can be

started. An acquisition time can be programmed to

occur between setting the GO/DONE bit and the actual

start of the conversion.

The following steps should be followed to do an A/D

conversion:

1. Configure the A/D module:

• Configure the required ADC pins as analog

pins using ANCON0, ANCON1

• Set voltage reference using ADCON0

• Select A/D input channel (ADCON0)

• Select A/D acquisition time (ADCON1)

• Select A/D conversion clock (ADCON1)

• Turn on A/D module (ADCON0)

2. Configure A/D interrupt (if desired):

• Clear ADIF bit

• Set ADIE bit

• Set GIE bit

3. Wait the required acquisition time (if required).

4. Start conversion:

• Set GO/DONE bit (ADCON0<1>)

5. Wait for A/D conversion to complete, by either:

• Polling for the GO/DONE bit to be cleared

• Waiting for the A/D interrupt

6. Read A/D Result registers (ADRESH:ADRESL);

clear bit, ADIF, if required.

7. For next conversion, go to step 1 or step 2, as

required. The A/D conversion time per bit is

defined as T

AD. A minimum wait of 2 TAD is

required before next acquisition starts.

FIGURE 21-2: ANALOG INPUT MODEL

VAIN CPIN

RSANx

5 pF

VDD

VT = 0.6V

VT = 0.6V ILEAKAGE

RIC ≤ 1k

Sampling

Switch

SS RSS

CHOLD = 25 pF

VSS

Sampling Switch

123 4

(kΩ)

VDD

±100 nA

Legend: CPIN

ILEAKAGE

RIC

CHOLD

= input capacitance

= threshold voltage

= leakage current at the pin due to

= interconnect resistance

= sampling switch

= sample/hold capacitance (from DAC)

various junctions

= sampling switch resistanceRSS

PIC18F87J50 FAMILY

21.1 A/D Acquisition Requirements

For the A/D Converter to meet its specified accuracy,

the charge holding capacitor (CHOLD) must be allowed

to fully charge to the input channel voltage level. The

Analog Input model is shown in Figure 21-2. The

source impedance (RS) and the internal sampling

switch (RSS) impedance directly affect the time

required to charge the capacitor CHOLD. The sampling

switch (RSS) impedance varies over the device voltage

(VDD). The source impedance affects the offset voltage

at the analog input (due to pin leakage current). The

maximum recommended impedance for analog

sources is 2.5 kΩ. After the analog input channel is

selected (changed), the channel must be sampled for

at least the minimum acquisition time before starting a

conversion.

To calculate the minimum acquisition time,

Equation 21-1 may be used. This equation assumes

that 1/2 LSb error is used (1024 steps for the A/D). The

1/2 LSb error is the maximum error allowed for the A/D

to meet its specified resolution.

Equation 21-3 shows the calculation of the minimum

required acquisition time, T

ACQ. This calculation is

based on the following application system

assumptions:

CHOLD =25 pF

Rs = 2.5 kΩ

Conversion Error ≤1/2 LSb

VDD =3V→Rss = 2 kΩ

Temperature = 85°C (system max.)

EQUATION 21-1: ACQUISITION TIME

EQUATION 21-2: A/D MINIMUM CHARGING TIME

EQUATION 21-3: CALCULATING THE MINIMUM REQUIRED ACQUISITION TIME

Note: When the conversion is started, the

holding capacitor is disconnected from the

input pin.

TACQ = Amplifier Settling Time + Holding Capacitor Charging Time + Temperature Coefficient

AMP + TC + TCOFF

VHOLD = (VREF – (VREF/2048)) • (1 – e(-TC/CHOLD(RIC + RSS + RS)))

TC = -(CHOLD)(RIC + RSS + RS) ln(1/2048)

TACQ =TAMP + TC + TCOFF

TAMP =0.2 μs

TCOFF = (Temp – 25°C)(0.02 μs/°C)

(85°C – 25°C)(0.02 μs/°C)

1.2 μs

Temperature coefficient is only required for temperatures > 25°C. Below 25°C, TCOFF = 0 ms.

TC = -(CHOLD)(RIC + RSS + RS) ln(1/2048) μs

-(25 pF) (1 kΩ + 2 kΩ + 2.5 kΩ) ln(0.0004883) μs

1.05 μs

TACQ =0.2 μs + 1.05 μs + 1.2 μs

2.45 μs

PIC18F87J50 FAMILY

21.2 Selecting and Configuring

Automatic Acquisition Time

The ADCON1 register allows the user to select an

acquisition time that occurs each time the GO/DONE

bit is set.

When the GO/DONE bit is set, sampling is stopped and

a conversion begins. The user is responsible for ensur-

ing the required acquisition time has passed between

selecting the desired input channel and setting the

GO/DONE bit. This occurs when the ACQT2:ACQT0

bits (ADCON1<5:3>) remain in their Reset state (‘000’)

and is compatible with devices that do not offer

programmable acquisition times.

If desired, the ACQT bits can be set to select a pro-

grammable acquisition time for the A/D module. When

the GO/DONE bit is set, the A/D module continues to

sample the input for the selected acquisition time, then

automatically begins a conversion. Since the acquisi-

tion time is programmed, there may be no need to wait

for an acquisition time between selecting a channel and

setting the GO/DONE bit.

In either case, when the conversion is completed, the

GO/DONE bit is cleared, the ADIF flag is set and the

A/D begins sampling the currently selected channel

again. If an acquisition time is programmed, there is

nothing to indicate if the acquisition time has ended or

if the conversion has begun.

21.3 Selecting the A/D Conversion

Clock

The A/D conversion time per bit is defined as TAD. The

A/D conversion requires 11 T

AD per 10-bit conversion.

The source of the A/D conversion clock is software

selectable.

There are seven possible options for TAD:

•2 T

OSC

•4 TOSC

•8 TOSC

•16 TOSC

•32 TOSC

•64 T

OSC

• Internal RC Oscillator

For correct A/D conversions, the A/D conversion clock

AD) must be as short as possible but greater than the

minimum TAD (see parameter 130 in Table 28-29 for

more information).

Table 21-1 shows the resultant T

AD times derived from

the device operating frequencies and the A/D clock

source selected.

TABLE 21-1: TAD vs. DEVICE OPERATING

FREQUENCIES

21.4 Configuring Analog Port Pins

The ANCON0, ANCON1, TRISA, TRISF and TRISH

registers control the operation of the A/D port pins. The

port pins needed as analog inputs must have their cor-

responding TRIS bits set (input). If the TRIS bit is

cleared (output), the digital output level (VOH or VOL)

will be converted.

The A/D operation is independent of the state of the

CHS3:CHS0 bits and the TRIS bits.

AD Clock Source (TAD)Maximum

Device

Frequency

Operation ADCS2:ADCS0

2 T

OSC 000 2.86 MHz

4 T

OSC 100 5.71 MHz

8 TOSC 001 11.43 MHz

16 TOSC 101 22.86 MHz

32 TOSC 010 45.71 MHz

64 TOSC 110 48.0 MHz

RC(2) x11 1.00 MHz(1)

Note 1: The RC source has a typical TAD time of

4μs.

2: For device frequencies above 1 MHz, the

device must be in Sleep mode for the

entire conversion or the A/D accuracy may

be out of specification.

Note 1: When reading the PORT register, all pins

configured as analog input channels will

read as cleared (a low level). Pins config-

ured as digital inputs will convert an

analog input. Analog levels on a digitally

configured input will be accurately

converted.

2: Analog levels on any pin defined as a

digital input may cause the digital input

buffer to consume current out of the

device’s specification limits.

PIC18F87J50 FAMILY

21.5 A/D Conversions

Figure 21-3 shows the operation of the A/D Converter

after the GO/DONE bit has been set and the

ACQT2:ACQT0 bits are cleared. A conversion is

started after the following instruction to allow entry into

Sleep mode before the conversion begins.

Figure 21-4 shows the operation of the A/D Converter

after the GO/DONE bit has been set, the

ACQT2:ACQT0 bits are set to ‘010’ and selecting a

4TAD acquisition time before the conversion starts.

Clearing the GO/DONE bit during a conversion will

abort the current conversion. The A/D Result register

pair will NOT be updated with the partially completed

A/D conversion sample. This means the

ADRESH:ADRESL registers will continue to contain

the value of the last completed conversion (or the last

value written to the ADRESH:ADRESL registers).

After the A/D conversion is completed or aborted, a

AD wait is required before the next acquisition can be

started. After this wait, acquisition on the selected

channel is automatically started.

21.6 Use of the ECCP2 Trigger

An A/D conversion can be started by the “Special Event

Trigger” of the ECCP2 module. This requires that the

CCP2M3:CCP2M0 bits (CCP2CON<3:0>) be

programmed as ‘1011’ and that the A/D module is

enabled (ADON bit is set). When the trigger occurs, the

GO/DONE bit will be set, starting the A/D acquisition

and conversion, and the Timer1 (or Timer3) counter will

be reset to zero. Timer1 (or Timer3) is reset to auto-

matically repeat the A/D acquisition period with minimal

software overhead (moving ADRESH/ADRESL to the

desired location). The appropriate analog input

channel must be selected and the minimum acquisition

period is either timed by the user, or an appropriate

TACQ time is selected before the Special Event Trigger

sets the GO/DONE bit (starts a conversion).

If the A/D module is not enabled (ADON is cleared), the

Special Event Trigger will be ignored by the A/D

module but will still reset the Timer1 (or Timer3)

counter.

FIGURE 21-3: A/D CONVERSION TAD CYCLES (ACQT2:ACQT0 = 000, TACQ = 0)

FIGURE 21-4: A/D CONVERSION TAD CYCLES (ACQT2:ACQT0 = 010, TACQ = 4 TAD)

Note: The GO/DONE bit should NOT be set in

the same instruction that turns on the A/D.

TAD1 TAD2TAD3TAD4 TAD5TAD6 TAD7TAD8TAD11

Set GO/DONE bit

Holding capacitor is disconnected from analog input (typically 100 ns)

TAD9 TAD10

TCY - TAD

Next Q4: ADRESH/ADRESL is loaded, GO/DONE bit is cleared,

ADIF bit is set, holding capacitor is connected to analog input.

Conversion starts

b9 b6 b5 b4 b3 b2 b1

b8 b7

1234567811

Set GO/DONE bit

(Holding capacitor is disconnected)

910

Next Q4: ADRESH:ADRESL is loaded, GO/DONE bit is cleared,

ADIF bit is set, holding capacitor is reconnected to analog input.

Conversion starts

123 4

(Holding capacitor continues

acquiring input)

TACQT Cycles TAD Cycles

Automatic

Acquisition

Time

b0b9 b6 b5 b4 b3 b2 b1

b8 b7

PIC18F87J50 FAMILY

21.7 A/D Converter Calibration

The A/D Converter in the PIC18F87J10 family of

devices includes a self-calibration feature which com-

pensates for any offset generated within the module.

The calibration process is automated and is initiated by

setting the ADCAL bit (ADCON1<6>). The next time

the GO/DONE bit is set, the module will perform a

“dummy” conversion (that is, with reading none of the

input channels) and store the resulting value internally

to compensate for the offset. Thus, subsequent offsets

will be compensated. An example of a calibration

routine is shown in Example 21-1.

The calibration process assumes that the device is in a

relatively steady-state operating condition. If A/D

calibration is used, it should be performed after each

device Reset or if there are other major changes in

operating conditions.

21.8 Operation in Power-Managed

Modes

The selection of the automatic acquisition time and A/D

conversion clock is determined in part by the clock

source and frequency while in a power-managed

mode.

If the A/D is expected to operate while the device is in

a power-managed mode, the ACQT2:ACQT0 and

ADCS2:ADCS0 bits in ADCON1 should be updated in

accordance with the power-managed mode clock that

will be used. After the power-managed mode is entered

(either of the power-managed Run modes), an A/D

acquisition or conversion may be started. Once an

acquisition or conversion is started, the device should

continue to be clocked by the same power-managed

mode clock source until the conversion has been com-

pleted. If desired, the device may be placed into the

corresponding power-managed Idle mode during the

conversion.

If the power-managed mode clock frequency is less

than 1 MHz, the A/D RC clock source should be

selected.

Operation in the Sleep mode requires the A/D RC clock

to be selected. If bits, ACQT2:ACQT0, are set to ‘000’

and a conversion is started, the conversion will be

delayed one instruction cycle to allow execution of the

SLEEP instruction and entry to Sleep mode. The IDLEN

and SCS bits in the OSCCON register must have

already been cleared prior to starting the conversion.

EXAMPLE 21-1: SAMPLE A/D CALIBRATION ROUTINE

BSF WDTCON,ADSHR ;Enable write/read to the shared SFR

BCF ANCON0,PCFG0 ;Make Channel 0 analog

BCF WDTCON,ADSHR ;Disable write/read to the shared SFR

BSF ADCON0,ADON ;Enable A/D module

BSF ADCON1,ADCAL ;Enable Calibration

BSF ADCON0,GO ;Start a dummy A/D conversion

CALIBRATION ;

BTFSC ADCON0,GO ;Wait for the dummy conversion to finish

BRA CALIBRATION ;

BCF ADCON1,ADCAL ;Calibration done, turn off calibration enable

;Proceed with the actual A/D conversion

PIC18F87J50 FAMILY

TABLE 21-2: SUMMARY OF A/D REGISTERS

Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Reset

Values

on Page:

INTCON GIE/GIEH PEIE/GIEL TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 61

PIR1 PMPIF ADIF RC1IF TX1IF SSP1IF CCP1IF TMR2IF TMR1IF 64

PIE1 PMPIE ADIE RC1IE TX1IE SSP1IE CCP1IE TMR2IE TMR1IE 64

IPR1 PMPIP ADIP RC1IP TX1IP SSP1IP CCP1IP TMR2IP TMR1IP 64

PIR2 OSCFIF CM2IF CM1IF USBIF BCL1IF LVDIF TMR3IF CCP2IF 64

PIE2 OSCFIE CM2IE CM1IE USBIE BCL1IE LVDIE TMR3IE CCP2IE 64

IPR2 OSCFIP CM2IP CM1IP USBIP BCL1IP LVDIP TMR3IP CCP2IP 64

ADRESH A/D Result Register High Byte 63

ADRESL A/D Result Register Low Byte 63

ADCON0(1) VCFG1 VCFG0 CHS3 CHS3 CHS1 CHS0 GO/DONE ADON 63

ANCON0(2) PCFG7 —— PCFG4 PCFG3 PCFG2 PCFG1 PCFG0 63

ADCON1(1) ADFM ADCAL ACQT2 ACQT1 ACQT0 ADCS2 ADCS1 ADCS0 63

ANCON1(2) PCFG15 PCFG14 PCFG13 PCFG12 PCFG11 PCFG10 ——63

CCP2CON P2M1 P2M0 DC2B1 DC2B0 CCP2M3 CCP2M2 CCP2M1 CCP2M0 63

PORTA —— RA5 RA4 RA3 RA2 RA1 RA0 65

TRISA —— TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 64

PORTF RF7 RF6 RF5 RF4 RF3 RF2 ——65

TRISF TRISF5 TRISF4 TRISF5 TRISF4 TRISF3 TRISF2 ——64

PORTH(3) RH7 RH6 RH5 RH4 RH3 RH2 RH1 RH0 65

TRISH(3) TRISH7 TRISH6 TRISH5 TRISH4 TRISH3 TRISH2 TRISH1 TRISH0 64

Legend: — = unimplemented, read as ‘0’. Shaded cells are not used for A/D conversion.

Note 1: Default (legacy) SFR at this address, available when WDTCON<4> = 0.

2: Configuration SFR, overlaps with default SFR at this address; available only when WDTCON<4> = 1.

3: This register is not implemented on 64-pin devices.

PIC18F87J50 FAMILY

22.0 UNIVERSAL SERIAL BUS

(USB)

This section describes the details of the USB

peripheral. Because of the very specific nature of the

module, knowledge of USB is expected. Some

high-level USB information is provided in Section 22.9

“Overview of USB” only for application design refer-

ence. Designers are encouraged to refer to the official

specification published by the USB Implementers

Forum (USB-IF) for the latest information. USB Speci-

fication Revision 2.0 is the most current specification at

the time of publication of this document.

22.1 Overview of the USB Peripheral

PIC18F87J10 family devices contain a full-speed and

low-speed, compatible USB Serial Interface Engine

(SIE) that allows fast communication between any USB

host and the PIC® microcontroller. The SIE can be

interfaced directly to the USB, utilizing the internal

transceiver.

Some special hardware features have been included to

improve performance. Dual access port memory in the

device’s data memory space (USB RAM) has been

supplied to share direct memory access between the

microcontroller core and the SIE. Buffer descriptors are

also provided, allowing users to freely program end-

point memory usage within the USB RAM space.

Figure 22-1 presents a general overview of the USB

peripheral and its features.

FIGURE 22-1: USB PERIPHERAL AND OPTIONS

3.9 Kbyte

USB RAM

USB

SIE

USB Control and

Transceiver

D+

D-

Internal Pull-ups

External 3.3V

Supply

FSEN

UPUEN

UTRDIS

USB Clock from the

Oscillator Module

Optional

External

Pull-ups(1)

(Low

(Full

PIC18F87J50 Family

USB Bus

Speed) Speed)

Note 1: The internal pull-up resistors should be disabled (UPUEN = 0) if external pull-up resistors are used.

Configuration

VUSB

PIC18F87J50 FAMILY

22.2 USB Status and Control

The operation of the USB module is configured and

managed through three control registers. In addition, a

total of 22 registers are used to manage the actual USB

transactions. The registers are:

• USB Control register (UCON)

• USB Configuration register (UCFG)

• USB Transfer Status register (USTAT)

• USB Device Address register (UADDR)

• Frame Number registers (UFRMH:UFRML)

• Endpoint Enable registers 0 through 15 (UEPn)

22.2.1 USB CONTROL REGISTER (UCON)

The USB Control register (Register 22-1) contains bits

needed to control the module behavior during transfers.

The register contains bits that control the following:

• Main USB Peripheral Enable

• Ping-Pong Buffer Pointer Reset

• Control of the Suspend mode

• Packet Transfer Disable

In addition, the USB Control register contains a status

bit, SE0 (UCON<5>), which is used to indicate the

occurrence of a single-ended zero on the bus. When

the USB module is enabled, this bit should be moni-

tored to determine whether the differential data lines

have come out of a single-ended zero condition. This

helps to differentiate the initial power-up state from the

USB Reset signal.

The overall operation of the USB module is controlled

by the USBEN bit (UCON<3>). Setting this bit activates

the module and resets all of the PPBI bits in the Buffer

Descriptor Table to ‘0’. This bit also activates the inter-

nal pull-up resistors, if they are enabled. Thus, this bit

can be used as a soft attach/detach to the USB.

Although all status and control bits are ignored when

this bit is clear, the module needs to be fully preconfig-

ured prior to setting this bit. This bit cannot be set until

the USB module is supplied with an active clock

source. If the PLL is being used, it should be enabled

at least two milliseconds (enough time for the PLL to

lock) before attempting to set the USBEN bit.

U-0 R/W-0 R-x R/C-0 R/W-0 R/W-0 R/W-0 U-0

— PPBRST SE0 PKTDIS USBEN(1) RESUME SUSPND —

bit 7 bit 0

Legend: C = Clearable bit

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 Unimplemented: Read as ‘0’

bit 6 PPBRST: Ping-Pong Buffers Reset bit

1 = Reset all Ping-Pong Buffer Pointers to the Even Buffer Descriptor (BD) banks

0 = Ping-Pong Buffer Pointers not being reset

bit 5 SE0: Live Single-Ended Zero Flag bit

1 = Single-ended zero active on the USB bus

0 = No single-ended zero detected

bit 4 PKTDIS: Packet Transfer Disable bit

1 = SIE token and packet processing disabled, automatically set when a SETUP token is received

0 = SIE token and packet processing enabled

bit 3 USBEN: USB Module Enable bit(1)

1 = USB module and supporting circuitry enabled (device attached)

0 = USB module and supporting circuitry disabled (device detached)

bit 2 RESUME: Resume Signaling Enable bit

1 = Resume signaling activated

0 = Resume signaling disabled

bit 1 SUSPND: Suspend USB bit

1 = USB module and supporting circuitry in Power Conserve mode, SIE clock inactive

0 = USB module and supporting circuitry in normal operation, SIE clock clocked at the configured rate

bit 0 Unimplemented: Read as ‘0’

Note 1: This bit cannot be set if the USB module does not have an appropriate clock source.

PIC18F87J50 FAMILY

The PPBRST bit (UCON<6>) controls the Reset status

when Double-Buffering mode (ping-pong buffering) is

used. When the PPBRST bit is set, all Ping-Pong

Buffer Pointers are set to the Even buffers. PPBRST

has to be cleared by firmware. This bit is ignored in

buffering modes not using ping-pong buffering.

The PKTDIS bit (UCON<4>) is a flag indicating that the

SIE has disabled packet transmission and reception.

This bit is set by the SIE when a SETUP token is

received to allow setup processing. This bit cannot be

set by the microcontroller, only cleared; clearing it

allows the SIE to continue transmission and/or

reception. Any pending events within the Buffer

Descriptor Table will still be available, indicated within

the USTAT register’s FIFO buffer.

The RESUME bit (UCON<2>) allows the peripheral to

perform a remote wake-up by executing Resume

signaling. To generate a valid remote wake-up,

firmware must set RESUME for 10 ms and then clear

the bit. For more information on Resume signaling, see

Sections 7.1.7.5, 11.4.4 and 11.9 in the USB 2.0

specification.

The SUSPND bit (UCON<1>) places the module and

supporting circuitry in a low-power mode. The input

clock to the SIE is also disabled. This bit should be set

by the software in response to an IDLEIF interrupt. It

should be reset by the microcontroller firmware after an

ACTVIF interrupt is observed. When this bit is active,

the device remains attached to the bus but the trans-

ceiver outputs remain Idle. The voltage on the VUSB pin

may vary depending on the value of this bit. Setting this

bit before a IDLEIF request will result in unpredictable

bus behavior.

22.2.2 USB CONFIGURATION REGISTER

(UCFG)

Prior to communicating over USB, the module’s

associated internal and/or external hardware must be

configured. Most of the configuration is performed with

the UCFG register (Register 22-2).The UFCG register

contains most of the bits that control the system level

behavior of the USB module. These include:

• Bus Speed (full speed versus low speed)

• On-Chip Pull-up Resistor Enable

• On-Chip Transceiver Enable

• Ping-Pong Buffer Usage

The UCFG register also contains two bits which aid in

module testing, debugging and USB certifications.

These bits control output enable state monitoring and

eye pattern generation.

22.2.2.1 Internal Transceiver

The USB peripheral has a built-in, USB 2.0, full-speed

and low-speed capable transceiver, internally con-

nected to the SIE. This feature is useful for low-cost,

single chip applications. The UTRDIS bit (UCFG<3>)

controls the transceiver; it is enabled by default

(UTRDIS = 0). The FSEN bit (UCFG<2>) controls the

transceiver speed; setting the bit enables full-speed

operation.

The on-chip USB pull-up resistors are controlled by the

UPUEN bit (UCFG<4>). They can only be selected

when the on-chip transceiver is enabled.

The internal USB transceiver obtains power from the

VUSB pin. In order to meet USB signalling level specifi-

cations, VUSB must be supplied with a voltage source

between 3.0V and 3.6V. The best electrical signal qual-

ity is obtained when a 3.3V supply is used and locally

bypassed with a high quality ceramic capacitor. The

capacitor should be placed as close as possible to the

VUSB and VSS pins found on the same edge of the

package (i.e., route ground of the capacitor to VSS

pin 25 on 64-lead TQFP packaged parts, or pin 31 on

80-lead TQFP parts).

VUSB should be held to within +/-300 mV of VDD. For

most applications, VUSB and VDD should be connected

together and powered from a nominal 3.3V source.

When the USB module is not being used, VUSB should

still be connected to VDD, but VUSB/VDD may be

connected to a 2.0V to 3.6V source.

The D+ and D- signal lines can be routed directly to

their respective pins on the USB connector or cable (for

hard-wired applications). No additional resistors,

capacitors, or magnetic components are required as

the D+ and D- drivers have controlled slew rate and

output impedance intended to match with the

characteristic impedance of the USB cable.

In order to meet the USB specifications, the traces

should be less than 30 cm long. Ideally, these traces

should be designed to have a characteristic impedance

matching that of the USB cable.

Note: While in Suspend mode, a typical

bus-powered USB device is limited to

500 μA of current. This is the complete

current which may be drawn by the PIC

device and its supporting circuitry. Care

should be taken to assure minimum

current draw when the device enters

Suspend mode.

Note: The USB speed, transceiver and pull-up

should only be configured during the mod-

ule setup phase. It is not recommended to

switch these settings while the module is

enabled.

PIC18F87J50 FAMILY

R/W-0 U-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

UTEYE —— UPUEN(1,2) UTRDIS(1) FSEN(1) PPB1 PPB0

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 UTEYE: USB Eye Pattern Test Enable bit

1 = Eye pattern test enabled

0 = Eye pattern test disabled

bit 6 Unimplemented: Always should be programmed to ‘0’(3)

bit 5 Unimplemented: Read as ‘0’

bit 4 UPUEN: USB On-Chip Pull-up Enable bit(1,2)

1 = On-chip pull-up enabled (pull-up on D+ with FSEN = 1 or D- with FSEN = 0)

0 = On-chip pull-up disabled

bit 3 UTRDIS: On-Chip Transceiver Disable bit(1)

1 = On-chip transceiver disabled

0 = On-chip transceiver active

bit 2 FSEN: Full-Speed Enable bit(1)

1 = Full-speed device: controls transceiver edge rates; requires input clock at 48 MHz

0 = Low-speed device: controls transceiver edge rates; requires input clock at 6 MHz

bit 1-0 PPB1:PPB0: Ping-Pong Buffers Configuration bits

11 = Even/Odd ping-pong buffers enabled for Endpoints 1 to 15

10 = Even/Odd ping-pong buffers enabled for all endpoints

01 = Even/Odd ping-pong buffer enabled for OUT Endpoint 0

00 = Even/Odd ping-pong buffers disabled

Note 1: The UPUEN, UTRDIS and FSEN bits should never be changed while the USB module is enabled. These

values must be preconfigured prior to enabling the module.

2: This bit is only valid when the on-chip transceiver is active (UTRDIS = 0); otherwise, it is ignored.

3: Firmware should never set this bit. Doing so may cause unexpected behavior.

PIC18F87J50 FAMILY

22.2.2.2 Internal Pull-up Resistors

The PIC18F87J10 family devices have built-in pull-up

resistors designed to meet the requirements for

low-speed and full-speed USB. The UPUEN bit

(UCFG<4>) enables the internal pull-ups. Figure 22-1

shows the pull-ups and their control.

22.2.2.3 External Pull-up Resistors

External pull-up may also be used. The VUSB pin may be

used to pull up D+ or D-. The pull-up resistor must be

1.5 kΩ (±5%) as required by the USB specifications.

Figure 22-2 shows an example.

FIGURE 22-2: EXTERNAL CIRCUITRY

22.2.2.4 Ping-Pong Buffer Configuration

The usage of ping-pong buffers is configured using the

PPB1:PPB0 bits. Refer to Section 22.4.4 “Ping-Pong

Buffering” for a complete explanation of the ping-pong

buffers.

22.2.2.5 Eye Pattern Test Enable

An automatic eye pattern test can be generated by the

module when the UCFG<7> bit is set. The eye pattern

output will be observable based on module settings,

meaning that the user is first responsible for configuring

the SIE clock settings, pull-up resistor and Transceiver

mode. In addition, the module has to be enabled.

Once UTEYE is set, the module emulates a switch from

a receive to transmit state and will start transmitting a

J-K-J-K bit sequence (K-J-K-J for full speed). The

sequence will be repeated indefinitely while the Eye

Pattern Test mode is enabled.

Note that this bit should never be set while the module

is connected to an actual USB system. This Test mode

is intended for board verification to aid with USB certi-

fication tests. It is intended to show a system developer

the noise integrity of the USB signals which can be

affected by board traces, impedance mismatches and

proximity to other system components. It does not

properly test the transition from a receive to a transmit

state. Although the eye pattern is not meant to replace

the more complex USB certification test, it should aid

during first order system debugging.

Note: The official USB specifications require that

USB devices must never source any cur-

rent onto the +5V VBUS line of the USB

cable. Additionally, USB devices must

never source any current on the D+ and D-

data lines whenever the +5V VBUS line is

less than 1.17V. In order to meet this

requirement, applications which are not

purely bus powered should monitor the

VBUS line and avoid turning on the USB

module and the D+ or D- pull-up resistor

until VBUS is greater than 1.17V. VBUS can

be connected to and monitored by any 5V

tolerant I/O pin for this purpose.

PIC®

Microcontroller Host

Controller/HUB

VUSB

D+

D-

Note: The above setting shows a typical connection

for a full-speed configuration using an on-chip

regulator and an external pull-up resistor.

1.5 kΩ

PIC18F87J50 FAMILY

22.2.3 USB STATUS REGISTER (USTAT)

The USB Status register reports the transaction status

within the SIE. When the SIE issues a USB transfer

complete interrupt, USTAT should be read to determine

the status of the transfer. USTAT contains the transfer

endpoint number, direction and Ping-Pong Buffer

Pointer value (if used).

The USTAT register is actually a read window into a

four-byte status FIFO, maintained by the SIE. It allows

the microcontroller to process one transfer while the

SIE processes additional endpoints (Figure 22-3).

When the SIE completes using a buffer for reading or

writing data, it updates the USTAT register. If another

USB transfer is performed before a transaction

complete interrupt is serviced, the SIE will store the

status of the next transfer into the status FIFO.

Clearing the transfer complete flag bit, TRNIF, causes

the SIE to advance the FIFO. If the next data in the

FIFO holding register is valid, the SIE will reassert the

interrupt within 6 T

CY of clearing TRNIF. If no additional

data is present, TRNIF will remain clear; USTAT data

will no longer be reliable.

FIGURE 22-3: USTAT FIFO

Note: The data in the USB Status register is valid

only when the TRNIF interrupt flag is

asserted.

Note: If an endpoint request is received while the

USTAT FIFO is full, the SIE will

automatically issue a NAK back to the

host.

Data Bus

USTAT from SIE

4-Byte FIFO

for USTAT

Clearing TRNIF

Advances FIFO

U-0 R-x R-x R-x R-x R-x R-x U-0

— ENDP3 ENDP2 ENDP1 ENDP0 DIR PPBI(1) —

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 Unimplemented: Read as ‘0’

bit 6-3 ENDP3:ENDP0: Encoded Number of Last Endpoint Activity bits

(represents the number of the BDT updated by the last USB transfer)

1111 = Endpoint 15

1110 = Endpoint 14

....

0001 = Endpoint 1

0000 = Endpoint 0

bit 2 DIR: Last BD Direction Indicator bit

1 = The last transaction was an IN token

0 = The last transaction was an OUT or SETUP token

bit 1 PPBI: Ping-Pong BD Pointer Indicator bit(1)

1 = The last transaction was to the Odd BD bank

0 = The last transaction was to the Even BD bank

bit 0 Unimplemented: Read as ‘0’

Note 1: This bit is only valid for endpoints with available Even and Odd BD registers.

PIC18F87J50 FAMILY

22.2.4 USB ENDPOINT CONTROL

Each of the 16 possible bidirectional endpoints has its

own independent control register, UEPn (where ‘n’ rep-

resents the endpoint number). Each register has an

identical complement of control bits. The prototype is

shown in Register 22-4.

The EPHSHK bit (UEPn<4>) controls handshaking for

the endpoint; setting this bit enables USB handshaking.

Typically, this bit is always set except when using

isochronous endpoints.

The EPCONDIS bit (UEPn<3>) is used to enable or

disable USB control operations (SETUP) through the

endpoint. Clearing this bit enables SETUP transac-

tions. Note that the corresponding EPINEN and

EPOUTEN bits must be set to enable IN and OUT

transactions. For Endpoint 0, this bit should always be

cleared since the USB specifications identify

Endpoint 0 as the default control endpoint.

The EPOUTEN bit (UEPn<2>) is used to enable or dis-

able USB OUT transactions from the host. Setting this

bit enables OUT transactions. Similarly, the EPINEN bit

(UEPn<1>) enables or disables USB IN transactions

from the host.

The EPSTALL bit (UEPn<0>) is used to indicate a

STALL condition for the endpoint. If a STALL is issued

on a particular endpoint, the EPSTALL bit for that end-

point pair will be set by the SIE. This bit remains set

until it is cleared through firmware, or until the SIE is

reset.

U-0 U-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

— — — EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL(1)

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7-5 Unimplemented: Read as ‘0’

bit 4 EPHSHK: Endpoint Handshake Enable bit

1 = Endpoint handshake enabled

0 = Endpoint handshake disabled (typically used for isochronous endpoints)

bit 3 EPCONDIS: Bidirectional Endpoint Control bit

If EPOUTEN = 1 and EPINEN = 1:

1 = Disable Endpoint n from control transfers; only IN and OUT transfers allowed

0 = Enable Endpoint n for control (SETUP) transfers; IN and OUT transfers also allowed

bit 2 EPOUTEN: Endpoint Output Enable bit

1 = Endpoint n output enabled

0 = Endpoint n output disabled

bit 1 EPINEN: Endpoint Input Enable bit

1 = Endpoint n input enabled

0 = Endpoint n input disabled

bit 0 EPSTALL: Endpoint Stall Enable bit(1)

1 = Endpoint n is stalled

0 = Endpoint n is not stalled

Note 1: Valid only if Endpoint n is enabled; otherwise, the bit is ignored.

PIC18F87J50 FAMILY

22.2.5 USB ADDRESS REGISTER

(UADDR)

The USB Address register contains the unique USB

address that the peripheral will decode when active.

UADDR is reset to 00h when a USB Reset is received,

indicated by URSTIF, or when a Reset is received from

the microcontroller. The USB address must be written

by the microcontroller during the USB setup phase

(enumeration) as part of the Microchip USB firmware

support.

22.2.6 USB FRAME NUMBER REGISTERS

(UFRMH:UFRML)

The Frame Number registers contain the 11-bit frame

number. The low-order byte is contained in UFRML,

while the three high-order bits are contained in

UFRMH. The register pair is updated with the current

frame number whenever a SOF token is received. For

the microcontroller, these registers are read-only. The

Frame Number registers are primarily used for

isochronous transfers. The contents of the UFRMH and

UFRML registers are only valid when the 48 MHz SIE

clock is active (i.e., contents are inaccurate when

SUSPND (UCON<1>) bit = 1).

22.3 USB RAM

USB data moves between the microcontroller core and

the SIE through a memory space known as the USB

RAM. This is a special dual access memory that is

mapped into the normal data memory space in Banks

0 through 15 (60h to F3Fh) for a total of 3.9 Kbyte

(Figure 22-4).

Bank 4 (400h through 4FFh) is used specifically for

endpoint buffer control, while Banks 0 through Bank3

and Banks 5 through Bank15 are available for USB

data. Depending on the type of buffering being used, all

but 8 bytes of Bank 4 may also be available for use as

USB buffer space.

Although USB RAM is available to the microcontroller

as data memory, the sections that are being accessed

by the SIE should not be accessed by the

microcontroller. A semaphore mechanism is used to

determine the access to a particular buffer at any given

time. This is discussed in Section 22.4.1.1 “Buffer

Ownership”.

FIGURE 22-4: IMPLEMENTATION OF

USB RAM IN DATA

MEMORY SPACE

400h

4FFh

500h

USB Data or

Buffer Descriptors,

USB Data or User Data

User Data

USB Data or

SFRs

3FFh

000h

F60h

FFFh

Banks 0

(USB RAM)

F5Fh

to 15

Access Ram

060h

05Fh

F40h

F3Fh

F00h

User Data

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22.4 Buffer Descriptors and the Buffer

Descriptor Table

The registers in Bank 4 are used specifically for end-

point buffer control in a structure known as the Buffer

Descriptor Table (BDT). This provides a flexible method

for users to construct and control endpoint buffers of

various lengths and configuration.

The BDT is composed of Buffer Descriptors (BD) which

are used to define and control the actual buffers in the

USB RAM space. Each BD, in turn, consists of four reg-

isters, where n represents one of the 64 possible BDs

(range of 0 to 63):

• BDnSTAT: BD Status register

• BDnCNT: BD Byte Count register

• BDnADRL: BD Address Low register

• BDnADRH: BD Address High register

BDs always occur as a four-byte block in

the sequence,

BDnSTAT:BDnCNT:BDnADRL:BDnADRH.

The address

of BDnSTAT is always an offset of (4n – 1) (in hexa-

decimal) from 400h, with n being the buffer descriptor

number.

Depending on the buffering configuration used

(Section 22.4.4 “Ping-Pong Buffering”), there are up

to 32, 33 or 64 sets of buffer descriptors. At a minimum,

the BDT must be at least 8 bytes long. This is because

the USB specification mandates that every device must

have Endpoint 0 with both input and output for initial

setup. Depending on the endpoint and buffering

configuration, the BDT can be as long as 256 bytes.

Although they can be thought of as Special Function

Registers, the Buffer Descriptor Status and Address

registers are not hardware mapped, as conventional

microcontroller SFRs in Bank 15 are. If the endpoint cor-

responding to a particular BD is not enabled, its registers

are not used. Instead of appearing as unimplemented

addresses, however, they appear as available RAM.

Only when an endpoint is enabled by setting the

UEPn<1> bit does the memory at those addresses

become functional as BD registers. As with any address

in the data memory space, the BD registers have an

indeterminate value on any device Reset.

An example of a BD for a 64-byte buffer, starting at

500h, is shown in Figure 22-5. A particular set of BD

registers is only valid if the corresponding endpoint has

been enabled using the UEPn register. All BD registers

are available in USB RAM. The BD for each endpoint

should be set up prior to enabling the endpoint.

22.4.1 BD STATUS AND CONFIGURATION

Buffer descriptors not only define the size of an end-

point buffer, but also determine its configuration and

control. Most of the configuration is done with the BD

Status register, BDnSTAT. Each BD has its own unique

and correspondingly numbered BDnSTAT register.

FIGURE 22-5: EXAMPLE OF A BUFFER

DESCRIPTOR

Unlike other control registers, the bit configuration for

the BDnSTAT register is context sensitive. There are

two distinct configurations, depending on whether the

microcontroller or the USB module is modifying the BD

and buffer at a particular time. Only three bit definitions

are shared between the two.

22.4.1.1 Buffer Ownership

Because the buffers and their BDs are shared between

the CPU and the USB module, a simple semaphore

mechanism is used to distinguish which is allowed to

update the BD and associated buffers in memory.

This is done by using the UOWN bit (BDnSTAT<7>) as

a semaphore to distinguish which is allowed to update

the BD and associated buffers in memory. UOWN is the

only bit that is shared between the two configurations

of BDnSTAT.

When UOWN is clear, the BD entry is “owned” by the

microcontroller core. When the UOWN bit is set, the BD

entry and the buffer memory are “owned” by the USB

peripheral. The core should not modify the BD or its

corresponding data buffer during this time. Note that

the microcontroller core can still read BDnSTAT while

the SIE owns the buffer and vice versa.

The buffer descriptors have a different meaning based

on the source of the register update. Prior to placing

ownership with the USB peripheral, the user can con-

figure the basic operation of the peripheral through the

BDnSTAT bits. During this time, the byte count and

buffer location registers can also be set.

When UOWN is set, the user can no longer depend on

the values that were written to the BDs. From this point,

the SIE updates the BDs as necessary, overwriting the

original BD values. The BDnSTAT register is updated

by the SIE with the token PID and the transfer count,

BDnCNT, is updated.

400h

USB Data

Buffer

BD0STAT

BD0CNT

BD0ADRL

BD0ADRH

401h

402h

403h

500h

53Fh

Descriptor

Note: Memory regions not to scale.

40h

00h

05h Starting

Size of Block

(xxh)

RegistersAddress Contents

Address

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The BDnSTAT byte of the BDT should always be the

last byte updated when preparing to arm an endpoint.

The SIE will clear the UOWN bit when a transaction

has completed.

No hardware mechanism exists to block access when

the UOWN bit is set. Thus, unexpected behavior can

occur if the microcontroller attempts to modify memory

when the SIE owns it. Similarly, reading such memory

may produce inaccurate data until the USB peripheral

returns ownership to the microcontroller.

22.4.1.2 BDnSTAT Register (CPU Mode)

When UOWN = 0, the microcontroller core owns the

BD. At this point, the other seven bits of the register

take on control functions.

The Data Toggle Sync Enable bit, DTSEN

(BDnSTAT<3>), controls data toggle parity checking.

Setting DTSEN enables data toggle synchronization by

the SIE. When enabled, it checks the data packet’s par-

ity against the value of DTS (BDnSTAT<6>). If a packet

arrives with an incorrect synchronization, the data will

essentially be ignored. It will not be written to the USB

RAM and the USB transfer complete interrupt flag will

not be set. The SIE will send an ACK token back to the

host to Acknowledge receipt, however. The effects of

the DTSEN bit on the SIE are summarized in

Table 22-1.

The Buffer Stall bit, BSTALL (BDnSTAT<2>), provides

support for control transfers, usually one-time stalls on

Endpoint 0. It also provides support for the

SET_FEATURE/CLEAR_FEATURE commands speci-

fied in Chapter 9 of the USB specification; typically,

continuous STALLs to any endpoint other than the

default control endpoint.

The BSTALL bit enables buffer stalls. Setting BSTALL

causes the SIE to return a STALL token to the host if a

received token would use the BD in that location. The

EPSTALL bit in the corresponding UEPn control regis-

ter is set and a STALL interrupt is generated when a

STALL is issued to the host. The UOWN bit remains set

and the BDs are not changed unless a SETUP token is

received. In this case, the STALL condition is cleared

and the ownership of the BD is returned to the

microcontroller core.

The BD9:BD8 bits (BDnSTAT<1:0>) store the two most

significant digits of the SIE byte count; the lower 8 digits

are stored in the corresponding BDnCNT register. See

Section 22.4.2 “BD Byte Count” for more

information.

TABLE 22-1: EFFECT OF DTSEN BIT ON ODD/EVEN (DATA0/DATA1) PACKET RECEPTION

OUT Packet

from Host

BDnSTAT Settings Device Response after Receiving Packet

DTSEN DTS Handshake UOWN TRNIF BDnSTAT and USTAT Status

DATA0 10ACK 01 Updated

DATA1 10ACK 10 Not Updated

DATA0 11ACK 10 Not Updated

DATA1 11ACK 01 Updated

Either 0xACK 01 Updated

Either, with error xxNAK 10 Not Updated

Legend: x = don’t care

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BD63STAT), CPU MODE (DATA IS WRITTEN TO THE SIDE)

R/W-x R/W-x U-0 U-0 R/W-x R/W-x R/W-x R/W-x

UOWN(1) DTS(2) —(3) —(3) DTSEN BSTALL BC9 BC8

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 UOWN: USB Own bit(1)

0 = The microcontroller core owns the BD and its corresponding buffer

bit 6 DTS: Data Toggle Synchronization bit(2)

1 = Data 1 packet

0 = Data 0 packet

bit 5-4 Unimplemented: These bits should always be programmed to ‘0’(3).

bit 3 DTSEN: Data Toggle Synchronization Enable bit

1 = Data toggle synchronization is enabled; data packets with incorrect Sync value will be ignored

except for a SETUP transaction, which is accepted even if the data toggle bits do not match

0 = No data toggle synchronization is performed

bit 2 BSTALL: Buffer Stall Enable bit

1 = Buffer stall enabled; STALL handshake issued if a token is received that would use the BD in the

given location (UOWN bit remains set, BD value is unchanged)

0 = Buffer stall disabled

bit 1-0 BC9:BC8: Byte Count 9 and 8 bits

The byte count bits represent the number of bytes that will be transmitted for an IN token or received

during an OUT token. Together with BC<7:0>, the valid byte counts are 0-1023.

Note 1: This bit must be initialized by the user to the desired value prior to enabling the USB module.

2: This bit is ignored unless DTSEN = 1.

3: If these bits are set, USB communication may not work. Hence, these bits should always be maintained as

‘0’.

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22.4.1.3 BDnSTAT Register (SIE Mode)

When the BD and its buffer are owned by the SIE, most

of the bits in BDnSTAT take on a different meaning. The

configuration is shown in Register 22-6. Once UOWN

is set, any data or control settings previously written

there by the user will be overwritten with data from the

SIE.

The BDnSTAT register is updated by the SIE with the

token Packet Identifier (PID) which is stored in

BDnSTAT<5:3>. The transfer count in the correspond-

ing BDnCNT register is updated. Values that overflow

the 8-bit register carry over to the two most significant

digits of the count, stored in BDnSTAT<1:0>.

22.4.2 BD BYTE COUNT

The byte count represents the total number of bytes

that will be transmitted during an IN transfer. After an IN

transfer, the SIE will return the number of bytes sent to

the host.

For an OUT transfer, the byte count represents the

maximum number of bytes that can be received and

stored in USB RAM. After an OUT transfer, the SIE will

return the actual number of bytes received. If the

number of bytes received exceeds the corresponding

byte count, the data packet will be rejected and a NAK

handshake will be generated. When this happens, the

byte count will not be updated.

The 10-bit byte count is distributed over two registers.

The lower 8 bits of the count reside in the BDnCNT

This represents a valid byte range of 0 to 1023.

22.4.3 BD ADDRESS VALIDATION

The BD Address register pair contains the starting RAM

address location for the corresponding endpoint buffer.

No mechanism is available in hardware to validate the

BD address.

If the value of the BD address does not point to an

address in the USB RAM, or if it points to an address

within another endpoint’s buffer, data is likely to be lost

or overwritten. Similarly, overlapping a receive buffer

(OUT endpoint) with a BD location in use can yield

unexpected results. When developing USB

applications, the user may want to consider the

inclusion of software-based address validation in their

code.

BD63STAT), SIE MODE (DATA RETURNED BY THE SIDE TO THE MCU)

R/W-x U-x R/W-x R/W-x R/W-x R/W-x R/W-x R/W-x

UOWN — PID3 PID2 PID1 PID0 BC9 BC8

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 UOWN: USB Own bit

1 = The SIE owns the BD and its corresponding buffer

bit 6 Reserved: Not written by the SIE

bit 5-2 PID3:PID0: Packet Identifier bits

The received token PID value of the last transfer (IN, OUT or SETUP transactions only).

bit 1-0 BC9:BC8: Byte Count 9 and 8 bits

These bits are updated by the SIE to reflect the actual number of bytes received on an OUT transfer

and the actual number of bytes transmitted on an IN transfer.

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22.4.4 PING-PONG BUFFERING

An endpoint is defined to have a ping-pong buffer when

it has two sets of BD entries: one set for an Even

transfer and one set for an Odd transfer. This allows the

CPU to process one BD while the SIE is processing the

other BD. Double-buffering BDs in this way allows for

maximum throughput to/from the USB.

The USB module supports four modes of operation:

• No ping-pong support

• Ping-pong buffer support for OUT Endpoint 0 only

• Ping-pong buffer support for all endpoints

• Ping-pong buffer support for all other Endpoints

except Endpoint 0

The ping-pong buffer settings are configured using the

PPB1:PPB0 bits in the UCFG register.

The USB module keeps track of the Ping-Pong Pointer

individually for each endpoint. All pointers are initially

reset to the Even BD when the module is enabled. After

the completion of a transaction (UOWN cleared by the

SIE), the pointer is toggled to the Odd BD. After the

completion of the next transaction, the pointer is

toggled back to the Even BD and so on.

The Even/Odd status of the last transaction is stored in

the PPBI bit of the USTAT register. The user can reset

all Ping-Pong Pointers to Even using the PPBRST bit.

Figure 22-6 shows the four different modes of

operation and how USB RAM is filled with the BDs.

BDs have a fixed relationship to a particular endpoint,

depending on the buffering configuration. The mapping

of BDs to endpoints is detailed in Table 22-2. This

relationship also means that gaps may occur in the

BDT if endpoints are not enabled contiguously. This

theoretically means that the BDs for disabled endpoints

could be used as buffer space. In practice, users

should avoid using such spaces in the BDT unless a

method of validating BD addresses is implemented.

FIGURE 22-6: BUFFER DESCRIPTOR TABLE MAPPING FOR BUFFERING MODES

EP1 IN Even

EP1 OUT Even

EP1 OUT Odd

EP1 IN Odd

Descriptor

EP1 IN

EP15 IN

EP1 OUT

EP0 OUT

PPB1:PPB0 = 00

EP0 IN

EP1 IN

No Ping-Pong

EP15 IN

EP0 IN

EP0 OUT Even

PPB1:PPB0 = 01

EP0 OUT Odd

EP1 OUT

Ping-Pong Buffer

EP15 IN Odd

EP0 IN Even

EP0 OUT Even

PPB1:PPB0 = 10

EP0 OUT Odd

EP0 IN Odd

Ping-Pong Buffers

Descriptor

400h

4FFh 4FFh 4FFh

400h 400h

47Fh

483h

Available

Data RAM Available

Data RAM

Maximum Memory

Used: 128 bytes

Maximum BDs:

32 (BD0 to BD31)

Maximum Memory

Used: 132 bytes

Maximum BDs:

33 (BD0 to BD32)

Maximum Memory

Used: 256 bytes

Maximum BDs: 6

4 (BD0 to BD63)

Note: Memory area not shown to scale.

Descriptor

Buffers on EP0 OUT on all EPs

EP1 IN Even

EP1 OUT Even

EP1 OUT Odd

EP1 IN Odd

Descriptor

EP15 IN Odd

EP0 OUT

PPB1:PPB0 = 11

EP0 IN

Ping-Pong Buffers

Descriptor

4FFh

400h

Maximum Memory

Used: 248 bytes

Maximum BDs:

62 (BD0 to BD61)

on all other EPs

except EP0

Available

Data RAM

4F7h

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TABLE 22-2: ASSIGNMENT OF BUFFER DESCRIPTORS FOR THE DIFFERENT

BUFFERING MODES

TABLE 22-3: SUMMARY OF USB BUFFER DESCRIPTOR TABLE REGISTERS

Endpoint

BDs Assigned to Endpoint

Mode 0

(No Ping-Pong)

Mode 1

(Ping-Pong on EP0 OUT)

Mode 2

(Ping-Pong on all EPs)

Mode 3

(Ping-Pong on all other EPs,

except EP0)

Out In Out In Out In Out In

0 0 1 0 (E), 1 (O) 2 0 (E), 1 (O) 2 (E), 3 (O) 0 1

1 2 3 3 4 4 (E), 5 (O) 6 (E), 7 (O) 2 (E), 3 (O) 4 (E), 5 (O)

2 4 5 5 6 8 (E), 9 (O) 10 (E), 11 (O) 6 (E), 7 (O) 8 (E), 9 (O)

3 6 7 7 8 12 (E), 13 (O) 14 (E), 15 (O) 10 (E), 11 (O) 12 (E), 13 (O)

4 8 9 9 10 16 (E), 17 (O) 18 (E), 19 (O) 14 (E), 15 (O) 16 (E), 17 (O)

5 10 11 11 12 20 (E), 21 (O) 22 (E), 23 (O) 18 (E), 19 (O) 20 (E), 21 (O)

6 12 13 13 14 24 (E), 25 (O) 26 (E), 27 (O) 22 (E), 23 (O) 24 (E), 25 (O)

7 14 15 15 16 28 (E), 29 (O) 30 (E), 31 (O) 26 (E), 27 (O) 28 (E), 29 (O)

8 16 17 17 18 32 (E), 33 (O) 34 (E), 35 (O) 30 (E), 31 (O) 32 (E), 33 (O)

9 18 19 19 20 36 (E), 37 (O) 38 (E), 39 (O) 34 (E), 35 (O) 36 (E), 37 (O)

10 20 21 21 22 40 (E), 41 (O) 42 (E), 43 (O) 38 (E), 39 (O) 40 (E), 41 (O)

11 22 23 23 24 44 (E), 45 (O) 46 (E), 47 (O) 42 (E), 43 (O) 44 (E), 45 (O)

12 24 25 25 26 48 (E), 49 (O) 50 (E), 51 (O) 46 (E), 47 (O) 48 (E), 49 (O)

13 26 27 27 28 52 (E), 53 (O) 54 (E), 55 (O) 50 (E), 51 (O) 52 (E), 53 (O)

14 28 29 29 30 56 (E), 57 (O) 58 (E), 59 (O) 54 (E), 55 (O) 56 (E), 57 (O)

15 30 31 31 32 60 (E), 61 (O) 62 (E), 63 (O) 58 (E), 59 (O) 60 (E), 61 (O)

Legend: (E) = Even transaction buffer, (O) = Odd transaction buffer

Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

BDnSTAT(1) UOWN DTS(4) PID3(2) PID2(2) PID1(2)

DTSEN(3)

PID0(2)

BSTALL(3)

BC9 BC8

BDnCNT(1) Byte Count

BDnADRL(1) Buffer Address Low

BDnADRH(1) Buffer Address High

Note 1: For buffer descriptor registers, n may have a value of 0 to 63. For the sake of brevity, all 64 registers are

shown as one generic prototype. All registers have indeterminate Reset values (xxxx xxxx).

2: Bits 5 through 2 of the BDnSTAT register are used by the SIE to return PID3:PID0 values once the register

is turned over to the SIE (UOWN bit is set). Once the registers have been under SIE control, the values

written for DTSEN and BSTALL are no longer valid.

3: Prior to turning the buffer descriptor over to the SIE (UOWN bit is cleared), bits 5 through 2 of the

BDnSTAT register are used to configure the DTSEN and BSTALL settings.

4: This bit is ignored unless DTSEN = 1.

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22.5 USB Interrupts

The USB module can generate multiple interrupt con-

ditions. To accommodate all of these interrupt sources,

the module is provided with its own interrupt logic

structure, similar to that of the microcontroller. USB

interrupts are enabled with one set of control registers

and trapped with a separate set of flag registers. All

sources are funneled into a single USB interrupt

request, USBIF (PIR2<4>), in the microcontroller’s

interrupt logic.

Figure 22-7 shows the interrupt logic for the USB

module. There are two layers of interrupt registers in

the USB module. The top level consists of overall USB

status interrupts; these are enabled and flagged in the

UIE and UIR registers, respectively. The second level

consists of USB error conditions, which are enabled

and flagged in the UEIR and UEIE registers. An

interrupt condition in any of these triggers a USB Error

Interrupt Flag (UERRIF) in the top level.

Interrupts may be used to trap routine events in a USB

transaction. Figure 22-8 shows some common events

within a USB frame and their corresponding interrupts.

FIGURE 22-7: USB INTERRUPT LOGIC FUNNEL

FIGURE 22-8: EXAMPLE OF A USB TRANSACTION AND INTERRUPT EVENTS

BTSEF

BTSEE

BTOEF

BTOEE

DFN8EF

DFN8EE

CRC16EF

CRC16EE

CRC5EF

CRC5EE

PIDEF

PIDEE

SOFIF

SOFIE

TRNIF

TRNIE

IDLEIF

IDLEIE

STALLIF

STALLIE

ACTVIF

ACTVIE

URSTIF

URSTIE

UERRIF

UERRIE

USBIF

Second Level USB Interrupts

(USB Error Conditions)

UEIR (Flag) and UEIE (Enable) Registers

Top Level USB Interrupts

(USB Status Interrupts)

UIR (Flag) and UIE (Enable) Registers

USB Reset

SOFRESET SETUP DATA STATUS SOF

SETUP Token Data ACK

OUT Token Empty Data ACK

Start-of-Frame (SOF)

IN Token Data ACK

SOFIF

URSTIF

1 ms Frame

Differential Data

From Host From Host To H os t

From Host To Host From Host

From Host From Host To H o s t

Transaction

Control Transfer(1)

Transaction

Complete

Note 1: The control transfer shown here is only an example showing events that can occur for every transaction. Typical control transfers

will spread across multiple frames.

Set TRNIF

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22.5.1 USB INTERRUPT STATUS

The USB Interrupt Status register (Register 22-7) con-

tains the flag bits for each of the USB status interrupt

sources. Each of these sources has a corresponding

interrupt enable bit in the UIE register. All of the USB

status flags are ORed together to generate the USBIF

interrupt flag for the microcontroller’s interrupt funnel.

Once an interrupt bit has been set by the SIE, it must

be cleared by software by writing a ‘0’. The flag bits

can also be set in software which can aid in firmware

debugging.

U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R-0 R/W-0

— SOFIF STALLIF IDLEIF(1) TRNIF(2) ACTVIF(3) UERRIF(4) URSTIF

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 Unimplemented: Read as ‘0’

bit 6 SOFIF: Start-of-Frame Token Interrupt bit

1 = A Start-of-Frame token received by the SIE

0 = No Start-of-Frame token received by the SIE

bit 5 STALLIF: A STALL Handshake Interrupt bit

1 = A STALL handshake was sent by the SIE

0 = A STALL handshake has not been sent

bit 4 IDLEIF: Idle Detect Interrupt bit(1)

1 = Idle condition detected (constant Idle state of 3 ms or more)

0 = No Idle condition detected

bit 3 TRNIF: Transaction Complete Interrupt bit(2)

1 = Processing of pending transaction is complete; read USTAT register for endpoint information

0 = Processing of pending transaction is not complete or no transaction is pending

bit 2 ACTVIF: Bus Activity Detect Interrupt bit(3)

1 = Activity on the D+/D- lines was detected

0 = No activity detected on the D+/D- lines

bit 1 UERRIF: USB Error Condition Interrupt bit(4)

1 = An unmasked error condition has occurred

0 = No unmasked error condition has occurred.

bit 0 URSTIF: USB Reset Interrupt bit

1 = Valid USB Reset occurred; 00h is loaded into UADDR register

0 = No USB Reset has occurred

Note 1: Once an Idle state is detected, the user may want to place the USB module in Suspend mode.

2: Clearing this bit will cause the USTAT FIFO to advance (valid only for IN, OUT and SETUP tokens).

3: This bit is typically unmasked only following the detection of a UIDLE interrupt event.

4: Only error conditions enabled through the UEIE register will set this bit. This bit is a status bit only and

cannot be set or cleared by the user.

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22.5.1.1 Bus Activity Detect Interrupt Bit

(ACTVIF)

The ACTVIF bit cannot be cleared immediately after

the USB module wakes up from Suspend or while the

USB module is suspended. A few clock cycles are

required to synchronize the internal hardware state

machine before the ACTVIF bit can be cleared by

firmware. Clearing the ACTVIF bit before the internal

hardware is synchronized may not have an effect on

the value of ACTVIF. Additionally, if the USB module

uses the clock from the 96 MHz PLL source, then after

clearing the SUSPND bit, the USB module may not be

immediately operational while waiting for the 96 MHz

PLL to lock. The application code should clear the

ACTVIF flag as shown in Example 22-1.

Only one ACTVIF interrupt is generated when resum-

ing from the USB bus Idle condition. If user firmware

clears the ACTVIF bit, the bit will not immediately

become set again, even when there is continuous bus

traffic. Bus traffic must cease long enough to generate

another IDLEIF condition before another ACTVIF

interrupt can be generated.

EXAMPLE 22-1: CLEARING ACTVIF BIT (UIR<2>)

Assembly:

BCF UCON, SUSPND

LOOP:

BTFSS UIR, ACTVIF

BRA DONE

BCF UIR, ACTVIF

BRA LOOP

DONE:

UCONbits.SUSPND = 0;

while (UIRbits.ACTVIF) { UIRbits.ACTVIF = 0; }

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22.5.2 USB INTERRUPT ENABLE

The USB Interrupt Enable register (Register 22-8)

contains the enable bits for the USB status interrupt

sources. Setting any of these bits will enable the

respective interrupt source in the UIR register.

The values in this register only affect the propagation

of an interrupt condition to the microcontroller’s inter-

rupt logic. The flag bits are still set by their interrupt

conditions, allowing them to be polled and serviced

without actually generating an interrupt.

U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

— SOFIE STALLIE IDLEIE TRNIE ACTVIE UERRIE URSTIE

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 Unimplemented: Read as ‘0’

bit 6 SOFIE: Start-of-Frame Token Interrupt Enable bit

1 = Start-of-Frame token interrupt enabled

0 = Start-of-Frame token interrupt disabled

bit 5 STALLIE: STALL Handshake Interrupt Enable bit

1 = STALL interrupt enabled

0 = STALL interrupt disabled

bit 4 IDLEIE: Idle Detect Interrupt Enable bit

1 = Idle detect interrupt enabled

0 = Idle detect interrupt disabled

bit 3 TRNIE: Transaction Complete Interrupt Enable bit

1 = Transaction interrupt enabled

0 = Transaction interrupt disabled

bit 2 ACTVIE: Bus Activity Detect Interrupt Enable bit

1 = Bus activity detect interrupt enabled

0 = Bus activity detect interrupt disabled

bit 1 UERRIE: USB Error Interrupt Enable bit

1 = USB error interrupt enabled

0 = USB error interrupt disabled

bit 0 URSTIE: USB Reset Interrupt Enable bit

1 = USB Reset interrupt enabled

0 = USB Reset interrupt disabled

PIC18F87J50 FAMILY

22.5.3 USB ERROR INTERRUPT STATUS

The USB Error Interrupt Status register (Register 22-9)

contains the flag bits for each of the error sources

within the USB peripheral. Each of these sources is

controlled by a corresponding interrupt enable bit in

the UEIE register. All of the USB error flags are ORed

together to generate the USB Error Interrupt Flag

(UERRIF) at the top level of the interrupt logic.

Each error bit is set as soon as the error condition is

detected. Thus, the interrupt will typically not

correspond with the end of a token being processed.

Once an interrupt bit has been set by the SIE, it must

be cleared by software by writing a ‘0’.

R/C-0 U-0 U-0 R/C-0 R/C-0 R/C-0 R/C-0 R/C-0

BTSEF —— BTOEF DFN8EF CRC16EF CRC5EF PIDEF

bit 7 bit 0

Legend:

R = Readable bit C = Clearable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 BTSEF: Bit Stuff Error Flag bit

1 = A bit stuff error has been detected

0 = No bit stuff error

bit 6-5 Unimplemented: Read as ‘0’

bit 4 BTOEF: Bus Turnaround Time-out Error Flag bit

1 = Bus turnaround time-out has occurred (more than 16 bit times of Idle from previous EOP elapsed)

0 = No bus turnaround time-out

bit 3 DFN8EF: Data Field Size Error Flag bit

1 = The data field was not an integral number of bytes

0 = The data field was an integral number of bytes

bit 2 CRC16EF: CRC16 Failure Flag bit

1 = The CRC16 failed

0 = The CRC16 passed

bit 1 CRC5EF: CRC5 Host Error Flag bit

1 = The token packet was rejected due to a CRC5 error

0 = The token packet was accepted

bit 0 PIDEF: PID Check Failure Flag bit

1 = PID check failed

0 = PID check passed

PIC18F87J50 FAMILY

22.5.4 USB ERROR INTERRUPT ENABLE

The USB Error Interrupt Enable register

(Register 22-10) contains the enable bits for each of

the USB error interrupt sources. Setting any of these

bits will enable the respective error interrupt source in

the UEIR register to propagate into the UERR bit at

the top level of the interrupt logic.

As with the UIE register, the enable bits only affect the

propagation of an interrupt condition to the micro-

controller’s interrupt logic. The flag bits are still set by

their interrupt conditions, allowing them to be polled

and serviced without actually generating an interrupt.

R/W-0 U-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

BTSEE —— BTOEE DFN8EE CRC16EE CRC5EE PIDEE

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 BTSEE: Bit Stuff Error Interrupt Enable bit

1 = Bit stuff error interrupt enabled

0 = Bit stuff error interrupt disabled

bit 6-5 Unimplemented: Read as ‘0’

bit 4 BTOEE: Bus Turnaround Time-out Error Interrupt Enable bit

1 = Bus turnaround time-out error interrupt enabled

0 = Bus turnaround time-out error interrupt disabled

bit 3 DFN8EE: Data Field Size Error Interrupt Enable bit

1 = Data field size error interrupt enabled

0 = Data field size error interrupt disabled

bit 2 CRC16EE: CRC16 Failure Interrupt Enable bit

1 = CRC16 failure interrupt enabled

0 = CRC16 failure interrupt disabled

bit 1 CRC5EE: CRC5 Host Error Interrupt Enable bit

1 = CRC5 host error interrupt enabled

0 = CRC5 host error interrupt disabled

bit 0 PIDEE: PID Check Failure Interrupt Enable bit

1 = PID check failure interrupt enabled

0 = PID check failure interrupt disabled

PIC18F87J50 FAMILY

22.6 USB Power Modes

Many USB applications will likely have several different

sets of power requirements and configuration. The

most common power modes encountered are Bus

Power Only, Self-Power Only and Dual Power with

Self-Power Dominance. The most common cases are

presented here. Also provided is a means of estimating

the current consumption of the USB transceiver.

22.6.1 BUS POWER ONLY

In Bus Power Only mode, all power for the application

is drawn from the USB (Figure 22-9). This is effectively

the simplest power method for the device.

In order to meet the inrush current requirements of the

USB 2.0 specifications, the total effective capacitance

appearing across VBUS and ground must be no more

than 10 µF. If not, some kind of inrush liming is

required. For more details, see section 7.2.4 of the

USB 2.0 specification.

According to the USB 2.0 specification, all USB devices

must also support a Low-Power Suspend mode. In the

USB Suspend mode, devices must consume no more

than 500 μA (or 2.5 mA for high powered devices that

are remote wake-up capable) from the 5V VBUS line of

the USB cable.

The host signals the USB device to enter the Suspend

mode by stopping all USB traffic to that device for more

than 3 ms. This condition will cause the IDLEIF bit in

the UIR register to become set.

During the USB Suspend mode, the D+ or D- pull-up

resistor must remain active, which will consume some

of the allowed suspend current: 500 μA/2.5 mA budget.

FIGURE 22-9: BUS POWER ONLY

22.6.2 SELF-POWER ONLY

In Self-Power Only mode, the USB application provides

its own power, with very little power being pulled from

the USB. Figure 22-10 shows an example. Note that an

attach indication is added to indicate when the USB

has been connected and the host is actively powering

VBUS.

In order to meet compliance specifications, the USB

module (and the D+ or D- pull-up resistor) should not

be enabled until the host actively drives VBUS high. One

of the 5.5V tolerant I/O pins may be used for this

purpose.

The application should never source any current onto

the 5V VBUS pin of the USB cable.

FIGURE 22-10: SELF-POWER ONLY

VDD

VUSB

VSS

VBUS

~5V

3.3V

Low IQ Regulator

VDD

VUSB

VSS

VSELF

~3.3V

Attach Sense

100 kΩ

VBUS

~5V

5.5V Tolerant

I/O pin

PIC18F87J50 FAMILY

22.6.3 DUAL POWER WITH SELF-POWER

DOMINANCE

Some applications may require a dual power option.

This allows the application to use internal power prima-

rily, but switch to power from the USB when no internal

power is available. Figure 22-11 shows a simple Dual

Power with Self-Power Dominance mode example,

which automatically switches between Self-Power Only

and USB Bus Power Only modes.

Dual power devices must also meet all of the special

requirements for inrush current and Suspend mode

current and must not enable the USB module until

VBUS is driven high. See Section 22.6.1 “Bus Power

Only” and Section 22.6.2 “Self-Power Only” for

descriptions of those requirements. Additionally, dual

power devices must never source current onto the 5V

VBUS pin of the USB cable.

FIGURE 22-11: DUAL POWER EXAMPLE

22.6.4 USB TRANSCEIVER CURRENT

CONSUMPTION

The USB transceiver consumes a variable amount of

current depending on the characteristic impedance of

the USB cable, the length of the cable, the VUSB supply

voltage and the actual data patterns moving across the

USB cable. Longer cables have larger capacitances

and consume more total energy when switching output

states.

Data patterns that consist of “IN” traffic consume far

more current than “OUT” traffic. IN traffic requires the

PIC® device to drive the USB cable, whereas OUT

traffic requires that the host drive the USB cable.

The data that is sent across the USB cable is NRZI

encoded. In the NRZI encoding scheme, ‘0’ bits cause

a toggling of the output state of the transceiver (either

from a “J” state to a “K” state, or vise versa). With the

exception of the effects of bit-stuffing, NRZI encoded ‘1’

bits do not cause the output state of the transceiver to

change. Therefore, IN traffic consisting of data bits of

value, ‘0’, cause the most current consumption, as the

transceiver must charge/discharge the USB cable in

order to change states.

More details about NRZI encoding and bit-stuffing can

be found in the USB 2.0 specification’s section 7.1,

although knowledge of such details is not required to

make USB applications using the PIC18F87J10 family

of microcontrollers. Among other things, the SIE han-

dles bit-stuffing/unstuffing, NRZI encoding/decoding

and CRC generation/checking in hardware.

The total transceiver current consumption will be

application-specific. However, to help estimate how

much current actually may be required in full-speed

applications, Equation 22-1 can be used.

Example 22-2 shows how this equation can be used for

a theoretical application.

Note: Users should keep in mind the limits for

devices drawing power from the USB.

According to USB Specification 2.0, this

cannot exceed 100 mA per low-power

device or 500 mA per high-power device.

VDD

VUSB

I/O pin

VSS

Attach Sense

VBUS

VSELF

100 kΩ

~3.3V

~5V

100 kΩ

3.3V

Low IQ

Regulator

PIC18F87J50 FAMILY

EQUATION 22-1: ESTIMATING USB TRANSCEIVER CURRENT CONSUMPTION

EXAMPLE 22-2: CALCULATING USB TRANSCEIVER CURRENT†

For this example, the following assumptions are made about the application:

• 3.3V will be applied to VUSB and VDD, with the core voltage regulator enabled.

• This is a full-speed application that uses one interrupt IN endpoint that can send one packet of 64 bytes every

1 ms, with no restrictions on the values of the bytes being sent. The application may or may not have additional

traffic on OUT endpoints.

• A regular USB “B” or “mini-B” connector will be used on the application circuit board.

In this case, PZERO = 100% = 1, because there should be no restriction on the value of the data moving through the

IN endpoint. All 64 kBps of data could potentially be bytes of value, 00h. Since ‘0’ bits cause toggling of the output

state of the transceiver, they cause the USB transceiver to consume extra current charging/discharging the cable. In

this case, 100% of the data bits sent can be of value ‘0’. This should be considered the “max” value, as normal data

will consist of a fair mix of ones and zeros.

This application uses 64 kBps for IN traffic out of the total bus bandwidth of 1.5 MBps (12 Mbps), therefore:

Since a regular “B” or “mini-B” connector is used in this application, the end user may plug in any type of cable up to

the maximum allowed 5 m length. Therefore, we use the worst-case length:

LCABLE = 5 meters

Assume IPULLUP = 2.2 mA. The actual value of IPULLUP will likely be closer to 218 μA, but allow for the worst-case.

USB bandwidth is shared between all the devices which are plugged into the root port (via hubs). If the application is

plugged into a USB 1.1 hub that has other devices plugged into it, your device may see host to device traffic on the

bus, even if it is not addressed to your device. Since any traffic, regardless of source, can increase the IPULLUP current

above the base 218 μA, it is safest to allow for the worst case of 2.2 mA.

Therefore:

† The calculated value should be considered an approximation and additional guardband or applica-

tion-specific product testing is recommended. The transceiver current is “in addition to” the rest of the

current consumed by the PIC18F87J10 family device that is needed to run the core, drive the other I/O

lines, power the various modules, etc.

IXCVR =+ IPULLUP

(60 mA • VUSB • PZERO • PIN • LCABLE)

(3.3V • 5m)

Legend: VUSB – Voltage applied to the VUSB pin in volts. (Should be 3.0V to 3.6V.)

PZERO – Percentage (in decimal) of the IN traffic bits sent by the PIC® device that are a value of ‘0’.

PIN – Percentage (in decimal) of total bus bandwidth that is used for IN traffic.

LCABLE – Length (in meters) of the USB cable. The USB 2.0 specification requires that full-speed

applications use cables no longer than 5m.

IPULLUP – Current which the nominal, 1.5 kΩ pull-up resistor (when enabled) must supply to the USB

cable. On the host or hub end of the USB cable, 15 kΩ nominal resistors (14.25 kΩ to 24.8 kΩ) are

present which pull both the D+ and D- lines to ground. During bus Idle conditions (such as between

packets or during USB Suspend mode), this results in up to 218 μA of quiescent current drawn at 3.3V.

IPULLUP is also dependant on bus traffic conditions and can be as high as 2.2 mA when the USB bandwidth

is fully utilized (either IN or OUT traffic) for data that drives the lines to the “K” state most of the time.

Pin = 64 kBps

1.5 MBps = 4.3% = 0.043

IXCVR = + 2.2 mA = 4.8 mA

(60 mA • 3.3V • 1 • 0.043 • 5m)

(3.3V • 5m)

PIC18F87J50 FAMILY

22.7 Oscillator

The USB module has specific clock requirements. For

full-speed operation, the clock source must be 48 MHz.

Even so, the microcontroller core and other peripherals

are not required to run at that clock speed. Available

clocking options are described in detail in Section 2.3

“Oscillator Settings for USB”.

22.8 USB Firmware and Drivers

Microchip provides a number of application-specific

resources, such as USB firmware and driver support.

Refer to www.microchip.com for the latest firmware and

driver support.

TABLE 22-4: REGISTERS ASSOCIATED WITH USB MODULE OPERATION(1)

Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Details on

Page:

INTCON GIE/GIEH PEIE/GIEL TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 81

IPR2 OSCFIP CM2IP CM1IP USBIP BCL1IP LVDIP TMR3IP CCP2IP 85

PIR2 OSCFIF CM2IF CM1IF USBIF BCL1IF LVDIF TMR3IF CCP2IF 85

PIE2 OSCFIE CM2IE CM1IE USBIE BCL1IE LVDIE TMR3IE CCP2IE 85

UCON — PPBRST SE0 PKTDIS USBEN RESUME SUSPND —87

UCFG UTEYE —— UPUEN UTRDIS FSEN PPB1 PPB0 87

USTAT — ENDP3 ENDP2 ENDP1 ENDP0 DIR PPBI —87

UADDR — ADDR6 ADDR5 ADDR4 ADDR3 ADDR2 ADDR1 ADDR0 87

UFRML FRM7 FRM6 FRM5 FRM4 FRM3 FRM2 FRM1 FRM0 87

UFRMH ————— FRM10 FRM9 FRM8 87

UIR — SOFIF STALLIF IDLEIF TRNIF ACTVIF UERRIF URSTIF 87

UIE — SOFIE STALLIE IDLEIE TRNIE ACTVIE UERRIE URSTIE 87

UEIR BTSEF —— BTOEF DFN8EF CRC16EF CRC5EF PIDEF 87

UEIE BTSEE —— BTOEE DFN8EE CRC16EE CRC5EE PIDEE 87

UEP0 ——— EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL 88

UEP1 ——— EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL 88

UEP2 ——— EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL 88

UEP3 ——— EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL 88

UEP4 ——— EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL 88

UEP5 ——— EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL 88

UEP6 ——— EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL 88

UEP7 ——— EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL 88

UEP8 ——— EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL 87

UEP9 ——— EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL 87

UEP10 ——— EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL 87

UEP11 ——— EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL 87

UEP12 ——— EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL 87

UEP13 ——— EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL 87

UEP14 ——— EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL 87

UEP15 ——— EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL 87

Legend: — = unimplemented, read as ‘0’. Shaded cells are not used by the USB module.

Note 1: This table includes only those hardware mapped SFRs located in Bank 15 of the data memory space. The Buffer

Descriptor registers, which are mapped into Bank 4 and are not true SFRs, are listed separately in Table 22-3.

PIC18F87J50 FAMILY

22.9 Overview of USB

This section presents some of the basic USB concepts

and useful information necessary to design a USB

device. Although much information is provided in this

section, there is a plethora of information provided

within the USB specifications and class specifications.

Thus, the reader is encouraged to refer to the USB

specifications for more information (www.usb.org). If

you are very familiar with the details of USB, then this

section serves as a basic, high-level refresher of USB.

22.9.1 LAYERED FRAMEWORK

USB device functionality is structured into a layered

framework graphically shown in Figure 22-12. Each

level is associated with a functional level within the

device. The highest layer, other than the device, is the

configuration. A device may have multiple configura-

tions. For example, a particular device may have

multiple power requirements based on Self-Power Only

or Bus Power Only modes.

For each configuration, there may be multiple

interfaces. Each interface could support a particular

mode of that configuration.

Below the interface is the endpoint(s). Data is directly

moved at this level. There can be as many as

16 bidirectional endpoints. Endpoint 0 is always a

control endpoint and by default, when the device is on

the bus, Endpoint 0 must be available to configure the

device.

22.9.2 FRAMES

Information communicated on the bus is grouped into

1 ms time slots, referred to as frames. Each frame can

contain many transactions to various devices and

endpoints. Figure 22-8 shows an example of a

transaction within a frame.

22.9.3 TRANSFERS

There are four transfer types defined in the USB

specification.

•Isochronous: This type provides a transfer

method for large amounts of data (up to

1023 bytes) with timely delivery ensured;

however, the data integrity is not ensured. This is

good for streaming applications where small data

loss is not critical, such as audio.

•Bulk: This type of transfer method allows for large

amounts of data to be transferred with ensured

data integrity; however, the delivery timeliness is

not ensured.

•Interrupt: This type of transfer provides for

ensured timely delivery for small blocks of data,

plus data integrity is ensured.

•Control: This type provides for device setup

control.

While full-speed devices support all transfer types,

low-speed devices are limited to interrupt and control

transfers only.

22.9.4 POWER

Power is available from the Universal Serial Bus. The

USB specification defines the bus power requirements.

Devices may either be self-powered or bus powered.

Self-powered devices draw power from an external

source, while bus powered devices use power supplied

from the bus.

FIGURE 22-12: USB LAYERS

Device

Configuration

Interface

Endpoint

Interface

Endpoint Endpoint Endpoint Endpoint

To other Configurations (if any)

To other Interfaces (if any)

PIC18F87J50 FAMILY

The USB specification limits the power taken from the

bus. Each device is ensured 100 mA at approximately

5V (one unit load). Additional power may be requested,

up to a maximum of 500 mA. Note that power above

one unit load is a request and the host or hub is not

obligated to provide the extra current. Thus, a device

capable of consuming more than one unit load must be

able to maintain a low-power configuration of a one unit

load or less, if necessary.

The USB specification also defines a Suspend mode.

In this situation, current must be limited to 500 μA,

averaged over 1 second. A device must enter a

Suspend state after 3 ms of inactivity (i.e., no SOF

tokens for 3 ms). A device entering Suspend mode

must drop current consumption within 10 ms after

Suspend. Likewise, when signaling a wake-up, the

device must signal a wake-up within 10 ms of drawing

current above the Suspend limit.

22.9.5 ENUMERATION

When the device is initially attached to the bus, the host

enters an enumeration process in an attempt to identify

the device. Essentially, the host interrogates the device,

gathering information such as power consumption, data

rates and sizes, protocol and other descriptive

information; descriptors contain this information. A

typical enumeration process would be as follows:

1. USB Reset: Reset the device. Thus, the device

is not configured and does not have an address

(address 0).

2. Get Device Descriptor: The host requests a

small portion of the device descriptor.

3. USB Reset: Reset the device again.

4. Set Address: The host assigns an address to the

device.

5. Get Device Descriptor: The host retrieves the

device descriptor, gathering info such as

manufacturer, type of device, maximum control

packet size.

6. Get configuration descriptors.

7. Get any other descriptors.

8. Set a configuration.

The exact enumeration process depends on the host.

22.9.6 DESCRIPTORS

There are eight different standard descriptor types of

which five are most important for this device.

22.9.6.1 Device Descriptor

The device descriptor provides general information,

such as manufacturer, product number, serial number,

the class of the device and the number of configurations.

There is only one device descriptor.

22.9.6.2 Configuration Descriptor

The configuration descriptor provides information on

the power requirements of the device and how many

different interfaces are supported when in this configu-

ration. There may be more than one configuration for a

device (i.e., low-power and high-power configurations).

22.9.6.3 Interface Descriptor

The interface descriptor details the number of end-

points used in this interface, as well as the class of the

interface. There may be more than one interface for a

configuration.

22.9.6.4 Endpoint Descriptor

The endpoint descriptor identifies the transfer type

(Section 22.9.3 “Transfers”) and direction, as well as

some other specifics for the endpoint. There may be

many endpoints in a device and endpoints may be

shared in different configurations.

22.9.6.5 String Descriptor

Many of the previous descriptors reference one or

more string descriptors. String descriptors provide

human readable information about the layer

(Section 22.9.1 “Layered Framework”) they

describe. Often these strings show up in the host to

help the user identify the device. String descriptors are

generally optional to save memory and are encoded in

a unicode format.

22.9.7 BUS SPEED

Each USB device must indicate its bus presence and

speed to the host. This is accomplished through a

1.5 kΩ resistor which is connected to the bus at the

time of the attachment event.

Depending on the speed of the device, the resistor

either pulls up the D+ or D- line to 3.3V. For a

low-speed device, the pull-up resistor is connected to

the D- line. For a full-speed device, the pull-up resistor

is connected to the D+ line.

22.9.8 CLASS SPECIFICATIONS AND

DRIVERS

USB specifications include class specifications which

operating system vendors optionally support.

Examples of classes include Audio, Mass Storage,

Communications and Human Interface (HID). In most

cases, a driver is required at the host side to ‘talk’ to the

USB device. In custom applications, a driver may need

to be developed. Fortunately, drivers are available for

most common host systems for the most common

classes of devices. Thus, these drivers can be reused.

PIC18F87J50 FAMILY

23.0 COMPARATOR MODULE

The analog comparator module contains two compara-

tors that can be independently configured in a variety of

ways. The inputs can be selected from the analog

inputs and two internal voltage references. The digital

outputs are available at the pin level and can also be

read through the control register. Multiple output and

interrupt event generation are also available. A generic

single comparator from the module is shown in

Figure 23-1.

Key features of the module includes:

• Independent comparator control

• Programmable input configuration

• Output to both pin and register levels

• Programmable output polarity

• Independent interrupt generation for each

comparator with configurable interrupt-on-change

23.1 Registers

The CMxCON registers (Register 23-1) select the input

and output configuration for each comparator, as well

as the settings for interrupt generation.

The CMSTAT register (Register 23-2) provides the out-

put results of the comparators. The bits in this register

are read-only.

FIGURE 23-1: COMPARATOR SIMPLIFIED BLOCK DIAGRAM

VIN-

VIN+

COE CxOUT

1(1)

2(1,2)

CCH1:CCH0

CxINB

CxINC

CxIND

VIRV

CxINA

CVREF

CON

Interrupt

Logic

EVPOL<4:3>

COUTx

(CMSTAT<1:0>)

CMxIF

CPOL

Polarity

Logic

CREF

Note 1: Available in 80-pin devices only.

2: Implemented in Comparator 2 only.

PIC18F87J50 FAMILY

R/W-0 R/W-0 R/W-0 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1

CON COE CPOL EVPOL1 EVPOL0 CREF CCH1 CCH0

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 CON: Comparator Enable bit

1 = Comparator is enabled

0 = Comparator is disabled

bit 6 COE: Comparator Output Enable bit

1 = Comparator output is present on the CxOUT pin

0 = Comparator output is internal only

bit 5 CPOL: Comparator Output Polarity Select bit

1 = Comparator output is inverted

0 = Comparator output is not inverted

bit 4-3 EVPOL1:EVPOL0: Interrupt Polarity Select bits

11 = Interrupt generation on any change of the output(1)

10 = Interrupt generation only on high-to-low transition of the output

01 = Interrupt generation only on low-to-high transition of the output

00 = Interrupt generation is disabled

bit 2 CREF: Comparator Reference Select bit (non-inverting input)

1 = Non-inverting input connects to internal CVREF voltage

0 = Non-inverting input connects to CxINA pin

bit 1-0 CCH1:CCH0: Comparator Channel Select bits

11 = Inverting input of comparator connects to VIRV

10 = Inverting input of comparator connects to CxIND pin(2)

01 = Inverting input of comparator connects to CxINC pin(2)

00 = Inverting input of comparator connects to CxINB pin

Note 1: The CMxIF is automatically set any time this mode is selected and must be cleared by the application after

the initial configuration.

2: Available in 80-pin devices only.

PIC18F87J50 FAMILY

U-0 U-0 U-0 U-0 U-0 U-0 R-1 R-1

— — — — — — COUT2 COUT1

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7-2 Unimplemented: Read as ‘0’

bit 1-0 COUT2:COUT1: Comparator x Status bits

If CPOL = 0 (non-inverted polarity):

1 = Comparator’s VIN+ > VIN-

0 = Comparator’s VIN+ < VIN-

If CPOL = 1 (inverted polarity):

1 = Comparator VIN+ < VIN-

0 = Comparator VIN+ > VIN-

PIC18F87J50 FAMILY

23.2 Comparator Operation

A single comparator is shown in Figure 23-2, along with

the relationship between the analog input levels and

the digital output. When the analog input at VIN+ is less

than the analog input VIN-, the output of the comparator

is a digital low level. When the analog input at VIN+ is

greater than the analog input VIN-, the output of the

comparator is a digital high level. The shaded areas of

the output of the comparator in Figure 23-2 represent

the uncertainty due to input offsets and response time.

FIGURE 23-2: SINGLE COMPARATOR

23.3 Comparator Response Time

Response time is the minimum time, after selecting a

new reference voltage or input source, before the com-

parator output has a valid level. The response time of

the comparator differs from the settling time of the volt-

age reference. Therefore, both of these times must be

considered when determining the total response to a

comparator input change. Otherwise, the maximum

delay of the comparators should be used (see

Section 28.0 “Electrical Characteristics”).

23.4 Analog Input Connection

Considerations

A simplified circuit for an analog input is shown in

Figure 23-3. Since the analog pins are connected to a

digital output, they have reverse biased diodes to VDD

and VSS. The analog input, therefore, must be between

VSS and VDD. If the input voltage deviates from this

range by more than 0.6V in either direction, one of the

diodes is forward biased and a latch-up condition may

occur. A maximum source impedance of 10 kΩ is

recommended for the analog sources. Any external

component connected to an analog input pin, such as

a capacitor or a Zener diode, should have very little

leakage current.

FIGURE 23-3: COMPARATOR ANALOG INPUT MODEL

Output

VIN-

VIN+

–

VIN+

VIN-

Output

RS < 10k

AIN

CPIN

5 pF

VDD

VT = 0.6V

RIC

ILEAKAGE

±500 nA

VSS

Legend: CPIN = Input Capacitance

VT= Threshold Voltage

ILEAKAGE = Leakage Current at the pin due to various junctions

RIC = Interconnect Resistance

RS= Source Impedance

VA = Analog Voltage

Comparator

Input

PIC18F87J50 FAMILY

23.5 Comparator Control and

Configuration

Each comparator has up to eight possible combina-

tions of inputs: up to four external analog inputs, and

one of two internal voltage references.

Both comparators allow a selection of the signal from

pin, CxINA, or the voltage from the comparator refer-

ence (CVREF) on the non-inverting channel. This is

compared to either CxINB, CxINC, CXIND or the micro-

controller’s fixed internal reference voltage (VIRV, 1.2V

nominal) on the inverting channel. The comparator

inputs and outputs are tied to fixed I/O pins, defined in

Table 23-1. The available comparator configurations

and their corresponding bit settings are shown in

Figure 23-4.

TABLE 23-1: COMPARATOR INPUTS AND

OUTPUTS

23.5.1 COMPARATOR ENABLE AND

INPUT SELECTION

Setting the CON bit of the CMxCON register

(CMxCON<7>) enables the comparator for operation.

Clearing the CON bit disables the comparator resulting

in minimum current consumption.

The CCH1:CCH0 bits in the CMxCON register

(CMxCON<1:0>) direct either one of three analog input

pins, or the Internal Reference Voltage (VIRV), to the

comparator VIN-. Depending on the comparator operat-

ing mode, either an external or internal voltage

reference may be used. The analog signal present at

VIN- is compared to the signal at VIN+ and the digital

output of the comparator is adjusted accordingly.

The external reference is used when CREF = 0

(CMxCON<2>) and VIN+ is connected to the CxINA

pin. When external voltage references are used, the

comparator module can be configured to have the ref-

erence sources externally. The reference signal must

be between VSS and VDD, and can be applied to either

pin of the comparator.

The comparator module also allows the selection of an

internally generated voltage reference (CVREF) from

the comparator voltage reference module. This module

is described in more detail in Section 23.0 “Compara-

tor Module”. The reference from the comparator

voltage reference module is only available when

CREF = 1. In this mode, the internal voltage reference

is applied to the comparator’s VIN+ pin.

23.5.1.1 Comparator Configurations in 64-Pin

and 80-Pin Devices

In PIC18F87J10 family devices, the C and D input

channels for both comparators are linked to pins in

PORTH and cannot be reassigned to alternate analog

inputs. Because of this, 64-pin devices offer a total of 4

different configurations for each comparator. In con-

trast, 80-pin devices offer a choice of 6 configurations

for Comparator 1, and 8 configurations for

Comparator 2. The configurations shown in Figure 23-4

are footnoted to indicate where they are not available.

23.5.2 COMPARATOR ENABLE AND

OUTPUT SELECTION

The comparator outputs are read through the CMSTAT

put and CMSTAT<1> reads the Comparator 2 output.

These bits are read-only.

The comparator outputs may also be directly output to

the RF1 and RF2 I/O pins by setting the COE bit

(CMxCON<6>). When enabled, multiplexors in the

output path of the pins switch to the output of the com-

parator. The TRISF<1:2> bits still function as the digital

output enable for the RF1 and RF2 pins while in this

mode.

By default, the comparator’s output is at logic high

whenever the voltage on VIN+ is greater than on VIN-.

The polarity of the comparator outputs can be inverted

using the CPOL bit (CMxCON<5>).

The uncertainty of each of the comparators is related to

the input offset voltage and the response time given in

the specifications, as discussed in Section 23.2

“Comparator Operation”.

Comparator Input or Output I/O Pin

C1INA (VIN+) RF6

C1INB (VIN-) RF5

C1INC (VIN-)(1) RH6(1)

C1OUT RF7

C2INA(VIN+) RF5

C2INB(VIN-) RF2

C2INC(VIN-)(1) RH4(1)

C2IND(VIN-)(1) RH5(1)

C2OUT RC5

Note 1: Available in 80-pin devices only.

Note: The comparator input pin selected by

CCH1:CH0 must be configured as an input

by setting both the corresponding TRISF or

TRISH bit, and the corresponding PCFG bit

in the ANCON1 register.

PIC18F87J50 FAMILY

FIGURE 23-4: COMPARATOR CONFIGURATIONS

VIN-

VIN+Off (Read as ‘0’)

Comparator Off

CON = 0, CREF = x, CCH<1:0> = xx COE

VIN-

VIN+

COE

Comparator CxINB > CxINA Compare

CON = 1, CREF = 0, CCH<1:0> = 00

CxINB

CxINA Cx

VIN-

VIN+

COE

Comparator CxINC > CxINA Compare

CON = 1, CREF = 0, CCH<1:0> = 01

CxINC

CxINA

VIN-

VIN+

COE

Comparator CxIND > CxINA Compare

CON = 1, CREF = 0, CCH<1:0> = 10

CxIND

CxINA Cx

VIN-

VIN+

COE

Comparator VIRV > CxINA Compare

CON = 1, CREF = 0, CCH<1:0> = 11

VIRV

CxINA

VIN-

VIN+

COE

Comparator CxINB > CVREF Compare

CON = 1, CREF = 1, CCH<1:0> = 00

CxINB

CVREF Cx

VIN-

VIN+

COE

Comparator CxINC > CVREF Compare

CON = 1, CREF = 1, CCH<1:0> = 01

CxINC

CVREF

VIN-

VIN+

COE

Comparator CxIND > CVREF Compare

CON = 1, CREF = 1, CCH<1:0> = 10

CxIND

CVREF Cx

VIN-

VIN+

COE

Comparator VIRV > CVREF Compare

CON = 1, CREF = 1, CCH<1:0> = 11

VIRV

CVREF CxOUT

Note: VIRV is the Internal Reference Voltage (see Table 28-2).

CxOUT

PIC18F87J50 FAMILY

23.6 Comparator Interrupts

The comparator interrupt flag is set whenever any of

the following occurs:

- Low-to-high transition of the comparator

output

- High-to-low transition of the comparator

output

- Any change in the comparator output.

The comparator interrupt selection is done by the

EVPOL1:EVPOL0 bits in the CMxCON register

(CMxCON<4:3>).

In order to provide maximum flexibility, the output of the

comparator may be inverted using the CPOL bit in the

CMxCON register (CMxCON<5>). This is functionally

identical to reversing the inverting and non-inverting

inputs of the comparator for a particular mode.

An interrupt is generated on the low-to-high or high-to-

low transition of the comparator output. This mode of

interrupt generation is dependent on EVPOL<1:0> in

the CMxCON register. When EVPOL<1:0> = 01 or 10,

the interrupt is generated on a low-to-high or high-to-

low transition of the comparator output. Once the

interrupt is generated, it is required to clear the interrupt

flag by software.

When EVPOL<1:0> = 11, the comparator interrupt flag

is set whenever there is a change in the output value of

either comparator. Software will need to maintain infor-

mation about the status of the output bits, as read from

CMSTAT<1:0>, to determine the actual change that

occurred. The CMxIF bits (PIR2<6:5>) are the Compar-

ator Interrupt Flags. The CMxIF bits must be reset by

clearing them. Since it is also possible to write a ‘1’ to

this register, a simulated interrupt may be initiated.

Table 23-2 shows the interrupt generation with respect

to comparator input voltages and EVPOL bit settings.

Both the CMxIE bits (PIE2<6:5>) and the PEIE bit

(INTCON<6>) must be set to enable the interrupt. In

addition, the GIE bit (INTCON<7>) must also be set. If

any of these bits are clear, the interrupt is not enabled,

though the CMxIF bits will still be set if an interrupt

condition occurs. A simplified diagram of the interrupt

section is shown in Figure 23-3.

TABLE 23-2: COMPARATOR INTERRUPT GENERATION

CPOL EVPOL<1:0> Comparator

Input Change COUTx Transition Interrupt

Generated

00 VIN+ > VIN- Low-to-High No

VIN+ < VIN- High-to-Low No

01 VIN+ > VIN- Low-to-High Yes

VIN+ < VIN- High-to-Low No

10 VIN+ > VIN- Low-to-High No

VIN+ < VIN- High-to-Low Yes

11 VIN+ > VIN- Low-to-High Yes

VIN+ < VIN- High-to-Low Yes

00 VIN+ > VIN- High-to-Low No

VIN+ < VIN- Low-to-High No

01 VIN+ > VIN- High-to-Low No

VIN+ < VIN- Low-to-High Yes

10 VIN+ > VIN- High-to-Low Yes

VIN+ < VIN- Low-to-High No

11 VIN+ > VIN- High-to-Low Yes

VIN+ < VIN- Low-to-High Yes

PIC18F87J50 FAMILY

23.7 Comparator Operation

During Sleep

When a comparator is active and the device is placed

in Sleep mode, the comparator remains active and the

interrupt is functional, if enabled. This interrupt will

wake-up the device from Sleep mode, when enabled.

Each operational comparator will consume additional

current. To minimize power consumption while in Sleep

mode, turn off the comparators (CON = 0) before

entering Sleep. If the device wakes up from Sleep, the

contents of the CMxCON register are not affected.

23.8 Effects of a Reset

A device Reset forces the CMxCON registers to their

Reset state. This forces both comparators and the

voltage reference to the OFF state.

TABLE 23-3: REGISTERS ASSOCIATED WITH COMPARATOR MODULE

Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Reset

Values

on Page:

INTCON GIE/GIEH PEIE/GIEL TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 61

PIR2 OSCFIF CM2IF CM1IF USBIF BCL1IF LVDIF TMR3IF CCP2IF 64

PIE2 OSCFIE CM2IE CM1IE USBIE BCL1IE LVDIE TMR3IE CCP2IE 64

IPR2 OSCFIP CM2IP CM1IP USBIP BCL1IP LVDIP TMR3IP CCP2IP 64

CMxCON CON COE CPOL EVPOL1 EVPOL0 CREF CCH1 CCH0 62

CVRCON(1) CVREN CVROE CVRR CVRSS CVR3 CVR2 CVR1 CVR0 65

CMSTAT — — — — — — COUT2 COUT1 65

ANCON1(1) PCFG15 PCFG14 PCFG13 PCFG12 PCFG11 PCFG10 ——63

ANCON0(1) PCFG7 —— PCFG4 PCFG3 PCFG2 PCFG1 PCFG0 63

PORTA ——RA5RA4 RA3 RA2 RA1 —65

TRISA ——TRISA5TRISA4 TRISA3 TRISA2 TRISA1 —64

LATA ——LATA5LATA4 LATA3 LATA2 LATA1 LATA0 64

PORTC RC7 RC6 RC5 RC4 RC3 RFC2 RFC1 RFC0 65

LATC LATC7 LATC6 LATC5 LATC4 LATC3 LATC2 LATC1 LATC0 64

TRISC TRISC7 TRISC6 TRISC5 TRISC4 TRISC3 TRISC2 TRISC1 TRISC0 64

PORTF RF7 RF6 RF5 RF4 RF3 RF2 ——65

LATF LATF7 LATF6 LATF5 LATF4 LATF3 LATF2 ——64

TRISF TRISF7 TRISF6 TRISF5 TRISF4 TRISF3 TRISF2 ——64

PORTH(2) RH7 RH6 RH5 RH4 RH3 RH2 RH1 RH0 65

TRISH(2) TRISH7 TRISH6 TRISH5 TRISH4 TRISH3 TRISH2 TRISH1 TRISH0 64

Legend: — = unimplemented, read as ‘0’. Shaded cells are not used for A/D conversion.

Note 1: Configuration SFR, overlaps with default SFR at this address; available only when WDTCON<4> = 1.

2: This register is not implemented on 64-pin devices.

PIC18F87J50 FAMILY

24.0 COMPARATOR VOLTAGE

REFERENCE MODULE

The comparator voltage reference is a 16-tap resistor

ladder network that provides a selectable reference

voltage. Although its primary purpose is to provide a

reference for the analog comparators, it may also be

used independently of them.

A block diagram of the module is shown in Figure 24-1.

The resistor ladder is segmented to provide two ranges

of CVREF values and has a power-down function to

conserve power when the reference is not being used.

The module’s supply reference can be provided from

either device VDD/VSS or an external voltage reference.

FIGURE 24-1: COMPARATOR VOLTAGE REFERENCE BLOCK DIAGRAM

16-to-1 MUX

CVR3:CVR0

CVREN

CVRSS = 0

VDD

VREF+CVRSS = 1

CVRSS = 0

VREF-CVRSS = 1

16 Steps

CVRR

CVREF

PIC18F87J50 FAMILY

24.1 Configuring the Comparator

Voltage Reference

The comparator voltage reference module is controlled

through the CVRCON register (Register 24-1). The

comparator voltage reference provides two ranges of

output voltage, each with 16 distinct levels. The range

to be used is selected by the CVRR bit (CVRCON<5>).

The primary difference between the ranges is the size

of the steps selected by the CVREF Selection bits

(CVR3:CVR0), with one range offering finer resolution.

The equations used to calculate the output of the

comparator voltage reference are as follows:

If CVRR = 1:

CVREF = ((CVR3:CVR0)/24) x (CVRSRC)

If CVRR = 0:

CVREF =(CVRSRC/4) + ((CVR3:CVR0)/32) x

(CVRSRC)

The comparator reference supply voltage can come

from either VDD and VSS, or the external VREF+ and

VREF- that are multiplexed with RA2 and RA3. The

voltage source is selected by the CVRSS bit

(CVRCON<4>).

The settling time of the comparator voltage reference

must be considered when changing the CVREF

output (see Table 28-3 in Section 28.0 “Electrical

Characteristics”).

The CVRCON register is a shared address SFR and

uses the same address as the PR4 register. The

CVRCON register is accessed by setting the ADSHR

bit (WDTCON<4>).

R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

CVREN CVROE(1) CVRR CVRSS CVR3 CVR2 CVR1 CVR0

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 CVREN: Comparator Voltage Reference Enable bit

1 =CVREF circuit powered on

0 =CV

REF circuit powered down

bit 6 CVROE: Comparator VREF Output Enable bit(1)

1 =CVREF voltage level is also output on the RF5/AN10/C1INB/CVREF pin

0 =CV

REF voltage is disconnected from the RF5/AN10/C1INB/CVREF pin

bit 5 CVRR: Comparator VREF Range Selection bit

1 = 0 to 0.667 CVRSRC, with CVRSRC/24 step size (low range)

0 = 0.25 CVRSRC to 0.75 CVRSRC, with CVRSRC/32 step size (high range)

bit 4 CVRSS: Comparator VREF Source Selection bit

1 = Comparator reference source, CVRSRC = (VREF+) – (VREF-)

0 = Comparator reference source, CVRSRC = AVDD – AVSS

bit 3-0 CVR3:CVR0: Comparator VREF Value Selection bits (0 ≤ (CVR3:CVR0) ≤ 15)

When CVRR = 1:

CVREF = ((CVR3:CVR0)/24) • (CVRSRC)

When CVRR = 0:

CVREF = (CVRSRC/4) + ((CVR3:CVR0)/32) • (CVRSRC)

Note 1: CVROE overrides the TRISF<5> bit setting.

PIC18F87J50 FAMILY

24.2 Voltage Reference Accuracy/Error

The full range of voltage reference cannot be realized

due to the construction of the module. The transistors

on the top and bottom of the resistor ladder network

(Figure 24-1) keep CVREF from approaching the refer-

ence source rails. The voltage reference is derived

from the reference source; therefore, the CVREF output

changes with fluctuations in that source. The tested

absolute accuracy of the voltage reference can be

found in Section 28.0 “Electrical Characteristics”.

24.3 Connection Considerations

The voltage reference module operates independently

of the comparator module. The output of the reference

generator may be connected to the RF5 pin if the

CVROE bit is set. Enabling the voltage reference out-

put onto RA2 when it is configured as a digital input will

increase current consumption. Connecting RF5 as a

digital output with CVRSS enabled will also increase

current consumption.

The RF5 pin can be used as a simple D/A output with

limited drive capability. Due to the limited current drive

capability, a buffer must be used on the voltage

reference output for external connections to VREF.

Figure 24-2 shows an example buffering technique.

24.4 Operation During Sleep

When the device wakes up from Sleep through an

interrupt or a Watchdog Timer time-out, the contents of

the CVRCON register are not affected. To minimize

current consumption in Sleep mode, the voltage

reference should be disabled.

24.5 Effects of a Reset

A device Reset disables the voltage reference by

clearing bit, CVREN (CVRCON<7>). This Reset also

disconnects the reference from the RA2 pin by clearing

bit, CVROE (CVRCON<6>) and selects the high-voltage

range by clearing bit, CVRR (CVRCON<5>). The CVR

value select bits are also cleared.

FIGURE 24-2: COMPARATOR VOLTAGE REFERENCE OUTPUT BUFFER EXAMPLE

TABLE 24-1: REGISTERS ASSOCIATED WITH COMPARATOR VOLTAGE REFERENCE

CVREF Output

–

CVREF

Module

Voltage

Reference

Output

Impedance

R(1)

RF5

Note 1: R is dependent upon the Comparator Voltage Reference Configuration bits, CVRCON<5> and CVRCON<3:0>.

PIC18F87J50

Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Reset

Values

on Page:

CVRCON(1) CVREN CVROE CVRR CVRSS CVR3 CVR2 CVR1 CVR0 65

CM1CON CON COE CPOL EVPOL1 EVPOL0 CREF CCH1 CCH0 62

CM2CON CON COE CPOL EVPOL1 EVPOL0 CREF CCH1 CCH0 62

TRISA TRISA7 TRISA6 TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 64

TRISF TRISF7 TRISF6 TRISF5 TRISF4 TRISF3 TRISF2 ——64

ANCON0(1) PCFG7 — — PCFG4 PCFG3 PCFG2 PCFG1 PCFG0 63

ANCON1(1) PCFG15 PCFG14 PCFG13 PCFG12 PCFG11 PCFG10 ——63

Legend: — = unimplemented, read as ‘0’. Shaded cells are not used with the comparator voltage reference.

Note 1: Configuration SFR, overlaps with default SFR at this address; available only when WDTCON<4> = 1.

PIC18F87J50 FAMILY

NOTES:

PIC18F87J50 FAMILY

25.0 SPECIAL FEATURES OF THE

CPU

PIC18F87J10 family devices include several features

intended to maximize reliability and minimize cost

through elimination of external components. These are:

• Oscillator Selection

• Resets:

- Power-on Reset (POR)

- Power-up Timer (PWRT)

- Oscillator Start-up Timer (OST)

- Brown-out Reset (BOR)

• Interrupts

• Watchdog Timer (WDT)

• Fail-Safe Clock Monitor

• Two-Speed Start-up

• Code Protection

• In-Circuit Serial Programming

The oscillator can be configured for the application

depending on frequency, power, accuracy and cost. All

of the options are discussed in detail in Section 2.0

“Oscillator Configurations”.

A complete discussion of device Resets and interrupts

is available in previous sections of this data sheet. In

addition to their Power-up and Oscillator Start-up

Timers provided for Resets, the PIC18F87J10 family of

devices have a configurable Watchdog Timer which is

controlled in software.

The inclusion of an internal RC oscillator also provides

the additional benefits of a Fail-Safe Clock Monitor

(FSCM) and Two-Speed Start-up. FSCM provides for

background monitoring of the peripheral clock and

automatic switchover in the event of its failure.

Two-Speed Start-up enables code to be executed

almost immediately on start-up, while the primary clock

source completes its start-up delays.

All of these features are enabled and configured by

setting the appropriate Configuration register bits.

25.1 Configuration Bits

The Configuration bits can be programmed (read as

‘0’) or left unprogrammed (read as ‘1’) to select various

device configurations. These bits are mapped starting

at program memory location 300000h. A complete list

is shown in Table 25-2. A detailed explanation of the

various bit functions is provided in Register 25-1

through Register 25-6.

25.1.1 CONSIDERATIONS FOR

CONFIGURING THE PIC18F87J50

FAMILY DEVICES

Unlike previous PIC18 microcontrollers, devices of the

PIC18F87J10 family do not use persistent memory

registers to store configuration information. The config-

uration bytes are implemented as volatile memory,

which means that configuration data must be

programmed each time the device is powered up.

Configuration data is stored in the four words at the top

of the on-chip program memory space, known as the

Flash Configuration Words. It is stored in program

memory in the same order shown in Table 25-2, with

CONFIG1L at the lowest address and CONFIG3H at

the highest. The data is automatically loaded in the

proper Configuration registers during device power-up.

When creating applications for these devices, users

should always specifically allocate the location of the

Flash Configuration Word for configuration data. This is

to make certain that program code is not stored in this

address when the code is compiled.

The volatile memory cells used for the Configuration

bits always reset to ‘1’ on Power-on Resets. For all

other type of Reset events, the previously programmed

values are maintained and used without reloading from

program memory.

The four Most Significant bits of CONFIG1H,

CONFIG2H and CONFIG3H in program memory

should also be ‘1111’. This makes these Configuration

Words appear to be NOP instructions in the remote

event that their locations are ever executed by

accident. Since Configuration bits are not implemented

in the corresponding locations, writing ‘1’s to these

locations has no effect on device operation.

To prevent inadvertent configuration changes during

code execution, all programmable Configuration bits

are write-once. After a bit is initially programmed during

a power cycle, it cannot be written to again. Changing

a device configuration requires that power to the device

be cycled.

PIC18F87J50 FAMILY

TABLE 25-1: MAPPING OF THE FLASH CONFIGURATION WORDS TO THE CONFIGURATION

REGISTERS

TABLE 25-2: CONFIGURATION BITS AND DEVICE IDs

Configuration Byte Code Space Address Configuration Register

Address

CONFIG1L XXXF8h 300000h

CONFIG1H XXXF9h 300001h

CONFIG2L XXXFAh 300002h

CONFIG2H XXXFBh 300003h

CONFIG3L XXXFCh 300004h

CONFIG3H XXXFDh 300005h

CONFIG4L(1) XXXFEh 300006h

CONFIG4H(1) XXXFFh 300007h

Note 1: Unimplemented in PIC18F87J10 family devices.

File Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Default/

Unprogrammed

Value

(1)

300000h CONFIG1L DEBUG XINST STVREN — PLLDIV2 PLLDIV1 PLLDIV0 WDTEN 111- 1111

300001h CONFIG1H —(2) —(2) —(2) —(2) —CP0 CPDIV1 CPDIV0 1111 -111

300002h CONFIG2L IESO FCMEN — — — FOSC2 FOSC1 FOSC0 11-- -111

300003h CONFIG2H —(2) —(2) —(2) —(2) WDTPS3 WDTPS2 WDTPS1 WDTPS0 1111 1111

300004h CONFIG3L WAIT(3) BW(3) EMB1(3) EMB0(3) EASHFT(3) — — — 1111 1---

300005h CONFIG3H —(2) —(2) —(2) —(2) MSSPMSK PMPMX(3) ECCPMX(3) CCP2MX 1111 1111

3FFFFEh DEVID1 DEV2 DEV1 DEV0 REV4 REV3 REV2 REV1 REV0 xxx0 0000(4)

3FFFFFh DEVID2 DEV10 DEV9 DEV8 DEV7 DEV6 DEV5 DEV4 DEV3 0100 00xx(4)

Legend: x = unknown, u = unchanged, - = unimplemented. Shaded cells are unimplemented, read as ‘0’.

Note 1: Values reflect the unprogrammed state as received from the factory and following Power-on Resets. In all other Reset

states, the configuration bytes maintain their previously programmed states.

2: The value of these bits in program memory should always be ‘1’. This ensures that the location is executed as a NOP if it

is accidentally executed.

3: Implemented in 80-pin devices only.

4: See Register 25-7 and Register 25-8 for DEVID values. These registers are read-only and cannot be programmed by

the user.

PIC18F87J50 FAMILY

R/WO-1 R/WO-1 R/WO-1 U-0 R/WO-1 R/WO-1 R/WO-1 R/WO-1

DEBUG XINST STVREN — PLLDIV2 PLLDIV1 PLLDIV0 WDTEN

bit 7 bit 0

Legend:

R = Readable bit WO = Write-Once bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 DEBUG: Background Debugger Enable bit

1 = Background debugger disabled; RB6 and RB7 configured as general purpose I/O pins

0 = Background debugger enabled; RB6 and RB7 are dedicated to In-Circuit Debug

bit 6 XINST: Extended Instruction Set Enable bit

1 = Instruction set extension and Indexed Addressing mode enabled

0 = Instruction set extension and Indexed Addressing mode disabled (Legacy mode)

bit 5 STVREN: Stack Overflow/Underflow Reset Enable bit

1 = Reset on stack overflow/underflow enabled

0 = Reset on stack overflow/underflow disabled

bit 4 Unimplemented: Read as ‘0’

bit 3-1 PLLDIV2:PLLDIV0: Oscillator Selection bits

Divider must be selected to provide a 4 MHz input into the 96 MHz PLL

111 = No divide - oscillator used directly (4 MHz input)

110 = Oscillator divided by 2 (8 MHz input)

101 = Oscillator divided by 3 (12 MHz input)

100 = Oscillator divided by 4 (16 MHz input)

011 = Oscillator divided by 5 (20 MHz input)

010 = Oscillator divided by 6 (24 MHz input)

001 = Oscillator divided by 10 (40 MHz input)

000 = Oscillator divided by 12 (48 MHz input)

bit 0 WDTEN: Watchdog Timer Enable bit

1 = WDT enabled

0 = WDT disabled (control is placed on SWDTEN bit)

PIC18F87J50 FAMILY

U-1 U-1 U-1 U-1 U-0 R/WO-1 R/WO-1 R/WO-1

— — — — — CP0 CPDIV1 CPDIV0

bit 7 bit 0

Legend:

R = Readable bit WO = Write-Once bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7-4 Unimplemented: Maintain as ‘1’

bit 3 Unimplemented: Read as ‘0’

bit 2 CP0: Code Protection bit

1 = Program memory is not code-protected

0 = Program memory is code-protected

bit 1-0 CPDIV1:CPDIV0: CPU System Clock Selection bits

11 = No CPU system clock divide

10 = CPU system clock divided by 2

01 = CPU system clock divided by 3

00 = CPU system clock divided by 6

PIC18F87J50 FAMILY

R/WO-1 R/WO-1 U-0 U-0 U-0 R/WO-1 R/WO-1 R/WO-1

IESO FCMEN — — — FOSC2 FOSC1 FOSC0

bit 7 bit 0

Legend:

R = Readable bit WO = Write-Once bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 IESO: Two-Speed Start-up (Internal/External Oscillator Switchover) Control bit

1 = Two-Speed Start-up enabled

0 = Two-Speed Start-up disabled

bit 6 FCMEN: Fail-Safe Clock Monitor Enable bit

1 = Fail-Safe Clock Monitor enabled

0 = Fail-Safe Clock Monitor disabled

bit 5-3 Unimplemented: Read as ‘0’

bit 2-0 FOSC2:FOSC0: Oscillator Selection bits

111 = ECPLL oscillator with PLL enabled, CLKO on RA6, ECPLL oscillator used by USB

110 = EC oscillator with CLKO on RA6 , EC oscillator used by USB

101 = HSPLL oscillator with PLL enabled, HSPLL oscillator used by USB

100 = HS oscillator, HS oscillator used by USB

011 = INTOSCPLLO, internal oscillator with INTOSCPLL enabled, CLKO on RA6 and port function

RA7

010 = INTOSCPLL, Internal oscillator with Port function on RA6 and RA7

001 = INTOSCO internal oscillator block (INTRC/INTOSC) with CLKO on RA6 Port function on RA7

000 = INTOSC internal oscillator block (INTRC/INTOSC) Port function on RA6 and RA7

PIC18F87J50 FAMILY

U-1 U-1 U-1 U-1 R/WO-1 R/WO-1 R/WO-1 R/WO-1

— — — — WDTPS3 WDTPS2 WDTPS1 WDTPS0

bit 7 bit 0

Legend:

R = Readable bit WO = Write-Once bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7-4 Unimplemented: Read as ‘0’

bit 3-0 WDTPS3:WDTPS0: Watchdog Timer Postscale Select bits

1111 = 1:32,768

1110 = 1:16,384

1101 = 1:8,192

1100 = 1:4,096

1011 = 1:2,048

1010 = 1:1,024

1001 = 1:512

1000 = 1:256

0111 = 1:128

0110 = 1:64

0101 = 1:32

0100 = 1:16

0011 = 1:8

0010 = 1:4

0001 = 1:2

0000 = 1:1

PIC18F87J50 FAMILY

R/WO-1 R/WO-1 R/WO-1 R/WO-1 R/WO-1 U-0 U-0 U-0

WAIT(1) BW(1) EMB1(1) EMB0(1) EASHFT(1) — — —

bit 7 bit 0

Legend:

R = Readable bit WO = Write-Once bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 WAIT: External Bus Wait Enable bit(1)

1 = Wait states on the external bus are disabled

0 = Wait states on the external bus are enabled and selected by MEMCON<5:4>

bit 6 BW: Data Bus Width Select bit(1)

1 = 16-Bit Data Width modes

0 = 8-Bit Data Width modes

bit 5-4 EMB1:EMB0: External Memory Bus Configuration bits(1)

11 = Microcontroller mode, external bus disabled

10 = Extended Microcontroller mode, 12-bit address width for external bus

01 = Extended Microcontroller mode, 16-bit address width for external bus

00 = Extended Microcontroller mode, 20-bit address width for external bus

bit 3 EASHFT: External Address Bus Shift Enable bit(1)

1 = Address shifting enabled – external address bus is shifted to start at 000000h

0 = Address shifting disabled – external address bus reflects the PC value

bit 2-0 Unimplemented: Read as ‘0’

Note 1: Implemented only on 80-pin devices.

PIC18F87J50 FAMILY

U-1 U-1 U-1 U-1 R/WO-1 R/WO-1 R/WO-1 R/WO-1

— — — — MSSPMSK PMPMX(1) ECCPMX(1) CCP2MX

bit 7 bit 0

Legend:

R = Readable bit WO = Write-Once bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7-4 Unimplemented: Maintain as ‘1’

bit 3 MSSPMSK: MSSP V3’s 7-Bit Address Masking Mode Enable bit

1 = 7-Bit Address Masking mode enable

0 = 5-Bit Address Masking mode enable

bit 2 PMPMX: PMP pin placement bit for the 80-pin TQFP(1)

1 = PMP pins placed on EMB

0 = PMP pins placed else where

bit 1 ECCPMX: ECCPx MUX bit(1)

1 = ECCP1 outputs (P1B/P1C) are multiplexed with RE6 and RE5;

ECCP3 outputs (P3B/P3C) are multiplexed with RE4 and RE3

0 = ECCP1 outputs (P1B/P1C) are multiplexed with RH7 and RH6;

ECCP3 outputs (P3B/P3C) are multiplexed with RH5 and RH4

bit 0 CCP2MX: ECCP2 MUX bit

1 = ECCP2/P2A is multiplexed with RC1

0 = ECCP2/P2A is multiplexed with RE7 in Microcontroller mode (all devices) or with RB3 in Extended

Microcontroller mode (80-pin devices only)

Note 1: Implemented only on 80-pin devices.

PIC18F87J50 FAMILY

RRRRRRRR

DEV2 DEV1 DEV0 REV4 REV3 REV2 REV1 REV0

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7-5 DEV2:DEV0: Device ID bits(1)

111 = PIC18F86J50

110 = reserved

101 = PIC18F85J50

100 = PIC18F67J50

011 = PIC18F66J55

010 = PIC18F66J50

001 = PIC18F87J50

000 = PIC18F65J50 and PIC18F86J55

bit 4-0 REV4:REV0: Revision ID bits

These bits are used to indicate the device revision.

Note 1: Where values for DEV2:DEV0 are shared by more than one device number, the specific device is always

identified by using the entire DEV10:DEV0 bit sequence. These bits are used with the DEV[10:3] bits in

the Device ID Register 2 to identify the part number.

RRRRRRRR

DEV10 DEV9 DEV8 DEV7 DEV6 DEV5 DEV4 DEV3

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7-0 DEV10:DEV3: Device ID bits(1)

These bits are used with the DEV2:DEV0 bits in the Device ID Register 1 to identify the part number.

0100 0001 = PIC18F65J50/66J50/66J55/67J50/85J50/86J50

0100 0010 = PIC18F87J50/86J55

Note 1: The values for DEV10:DEV3 may be shared with other device families. The specific device is always

identified by using the entire DEV10:DEV0 bit sequence.

PIC18F87J50 FAMILY

25.2 Watchdog Timer (WDT)

For PIC18F87J10 family devices, the WDT is driven by

the INTRC oscillator. When the WDT is enabled, the

clock source is also enabled. The nominal WDT period is

4 ms and has the same stability as the INTRC oscillator.

The 4 ms period of the WDT is multiplied by a 16-bit

postscaler. Any output of the WDT postscaler is selected

by a multiplexor, controlled by the WDTPS bits in Config-

uration Register 2H. Available periods range from about

4 ms to 135 seconds (2.25 minutes depending on

voltage, temperature and WDT postscaler). The WDT

and postscaler are cleared whenever a SLEEP or

CLRWDT instruction is executed, or a clock failure

(primary or Timer1 oscillator) has occurred.

25.2.1 CONTROL REGISTER

The WDTCON register (Register 25-9) is a readable

and writable register. The SWDTEN bit enables or dis-

ables WDT operation. This allows software to override

the WDTEN Configuration bit and enable the WDT only

if it has been disabled by the Configuration bit.

The ADSHR bit selects which SFRs currently are

selected and accessible. For additional details, see

Section 5.3.5.1 “Shared Address SFRs”.

LVDSTAT is a read-only status bit that is continuously

updated and provides information about the current

level of VDDCORE. This bit is only valid when the on-chip

voltage regulator is enabled.

FIGURE 25-1: WDT BLOCK DIAGRAM

Note 1: The CLRWDT and SLEEP instructions

clear the WDT and postscaler counts

when executed.

2: When a CLRWDT instruction is executed,

the postscaler count will be cleared.

INTRC Oscillator

WDT

Wake-up from

Reset

WDT

WDT Counter

Programmable Postscaler

1:1 to 1:32,768

Enable WDT

WDTPS3:WDTPS0

SWDTEN

CLRWDT

Power-Managed

Reset

All Device Resets

Sleep

INTRC Control

÷128

Modes

PIC18F87J50 FAMILY

TABLE 25-3: SUMMARY OF WATCHDOG TIMER REGISTERS

R/W-0 R-x U-0 R/W-0 U-0 U-0 U-0 U-0

REGSLP(2) LVDSTAT — ADSHR — — —SWDTEN

(1)

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 REGSLP: Voltage Regulator Low-Power Operation Enable bit(2)

1 = On-chip regulator enters low-power operation when device enters Sleep mode

0 = On-chip regulator is active even in Sleep mode

bit 6 LVDSTAT: Low-Voltage Detect Status bit

1 = VDDCORE > 2.45V nominal

0 = VDDCORE < 2.45V nominal

bit 5 Unimplemented: Read as ‘0’

bit 4 ADSHR: Shared Address SFR Select bit

For details of bit operation, see Register 5-3.

bit 3-1 Unimplemented: Read as ‘0’

bit 0 SWDTEN: Software Controlled Watchdog Timer Enable bit(1)

1 = Watchdog Timer is on

0 = Watchdog Timer is off

Note 1: This bit has no effect if the Configuration bit, WDTEN, is enabled.

2: The REGSLP bit is automatically cleared when a Low-Voltage Detect condition occurs.

Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Reset Values

on Page:

RCON IPEN —CM RI TO PD POR BOR 62

WDTCON REGSLP LVDSTAT — ADSHR — — —SWDTEN 63

Legend: — = unimplemented, read as ‘0’. Shaded cells are not used by the Watchdog Timer.

PIC18F87J50 FAMILY

25.3 On-Chip Voltage Regulator

All of the PIC18F87J10 family devices power their core

digital logic at a nominal 2.5V. For designs that are

required to operate at a higher typical voltage, such as

3.3V, all devices in the PIC18F87J10 family incorporate

an on-chip regulator that allows the device to run its

core logic from VDD.

The regulator is controlled by the ENVREG pin. Tying

VDD to the pin enables the regulator, which in turn, pro-

vides power to the core from the other VDD pins. When

the regulator is enabled, a low-ESR filter capacitor

must be connected to the VDDCORE/VCAP pin

(Figure 25-2). This helps to maintain the stability of the

regulator. The recommended value for the filter capac-

itor is provided in Section 28.3 “DC Characteristics:

PIC18F87J50 Family (Industrial)”.

If ENVREG is tied to VSS, the regulator is disabled. In

this case, separate power for the core logic at a nomi-

nal 2.5V must be supplied to the device on the

VDDCORE/VCAP pin to run the I/O pins at higher voltage

levels, typically 3.3V. Alternatively, the VDDCORE/VCAP

and VDD pins can be tied together to operate at a lower

nominal voltage. Refer to Figure 25-2 for possible

configurations.

25.3.1 VOLTAGE REGULATOR TRACKING

MODE AND LOW-VOLTAGE

DETECTION

When it is enabled, the on-chip regulator provides a con-

stant voltage of 2.5V nominal to the digital core logic.

The regulator can provide this level from a VDD of about

2.5V, all the way up to the device’s VDDMAX. It does not

have the capability to boost VDD levels below 2.5V. In

order to prevent “brown-out” conditions, when the volt-

age drops too low for the regulator, the regulator enters

Tracking mode. In Tracking mode, the regulator output

follows VDD, with a typical voltage drop of 100 mV.

The on-chip regulator includes a simple Low-Voltage

Detect (LVD) circuit. If VDD drops too low to maintain

approximately 2.45V on VDDCORE, the circuit sets the

Low-Voltage Detect Interrupt Flag, LVDIF (PIR2<2>).

This can be used to generate an interrupt and put the

application into a low-power operational mode, or trig-

ger an orderly shutdown. Low-Voltage Detection is only

available when the regulator is enabled.

The Low-Voltage Detect interrupt is edge-sensitive and

will only be set once per falling edge of VDDCORE. Firm-

ware can clear the interrupt flag, but a new interrupt will

not be generated until VDDCORE rises back above, and

then falls below, the 2.45V nominal threshold. Device

Resets will reset the interrupt flag to ‘0’, even if

VDDCORE is less than 2.45V. When the regulator is

enabled, the LVDSTAT bit in the WDTCON register can

be polled to determine the current level of VDDCORE.

FIGURE 25-2: CONNECTIONS FOR THE

ON-CHIP REGULATOR

VDD

ENVREG

VDDCORE/VCAP

VSS

PIC18F87J50

3.3V(1)

2.5V(1)

VDD

ENVREG

VDDCORE/VCAP

VSS

PIC18F87J50

3.3V

Regulator Enabled (ENVREG tied to VDD):

Regulator Disabled (ENVREG tied to ground):

VDD

ENVREG

VDDCORE/VCAP

VSS

PIC18F87J50

2.5V(1)

Regulator Disabled (VDD tied to VDDCORE):

Note 1: These are typical operating voltages. Refer

to Section 28.1 “DC Characteristics:

Supply Voltage” for the full operating

ranges of VDD and VDDCORE.

PIC18F87J50 FAMILY

25.3.2 ON-CHIP REGULATOR AND BOR

When the on-chip regulator is enabled, PIC18F87J10

family devices also have a simple brown-out capability.

If the voltage supplied to the regulator is inadequate to

maintain a regulated level, the regulator Reset circuitry

will generate a Brown-out Reset. This event is captured

by the BOR flag bit (RCON<0>).

The operation of the Brown-out Reset is described in

more detail in Section 4.4 “Brown-out Reset (BOR)”

and Section 4.4.1 “Detecting BOR”. The brown-out

voltage levels are specific in Section 28.1 “DC Charac-

teristics: Supply Voltage PIC18F87J50 Family

(Industrial)”.

25.3.3 POWER-UP REQUIREMENTS

The on-chip regulator is designed to meet the power-up

requirements for the device. If the application does not

use the regulator, then strict power-up conditions must

be adhered to. While powering up, VDDCORE must

never exceed VDD by 0.3 volts.

25.3.4 OPERATION IN SLEEP MODE

When enabled, the on-chip regulator always consumes

a small incremental amount of current over IDD. This

includes when the device is in Sleep mode, even

though the core digital logic does not require power. To

provide additional savings in applications where power

resources are critical, the regulator can be configured

to automatically disable itself whenever the device

goes into Sleep mode. This feature is controlled by the

REGSLP bit (WDTCON<7>, Register 25-9). Setting

this bit disables the regulator in Sleep mode and

reduces its current consumption to a minimum.

Substantial Sleep mode power savings can be

obtained by setting the REGSLP bit, but device

wake-up time will increase in order to insure the regu-

lator has enough time to stabilize. The REGSLP bit is

automatically cleared by hardware when a Low-Voltage

Detect condition occurs.

25.4 Two-Speed Start-up

The Two-Speed Start-up feature helps to minimize the

latency period, from oscillator start-up to code execu-

tion, by allowing the microcontroller to use the INTRC

oscillator as a clock source until the primary clock

source is available. It is enabled by setting the IESO

Configuration bit.

Two-Speed Start-up should be enabled only if the

primary oscillator mode is HS or HSPLL

(Crystal-Based) modes. Since the EC and ECPLL

modes do not require an Oscillator Start-up Timer

(OST) delay, Two-Speed Start-up should be disabled.

When enabled, Resets and wake-ups from Sleep mode

cause the device to configure itself to run from the inter-

nal oscillator block as the clock source, following the

time-out of the Power-up Timer after a Power-on Reset

is enabled. This allows almost immediate code

execution while the primary oscillator starts and the

OST is running. Once the OST times out, the device

automatically switches to PRI_RUN mode.

In all other power-managed modes, Two-Speed

Start-up is not used. The device will be clocked by the

currently selected clock source until the primary clock

source becomes available. The setting of the IESO bit

is ignored.

FIGURE 25-3: TIMING TRANSITION FOR TWO-SPEED START-UP (INTRC TO HSPLL)

Q1 Q3 Q4

OSC1

Peripheral

Program PC PC + 2

INTRC

PLL Clock

PC + 6

Output

Q3 Q4 Q1

CPU Clock

PC + 4

Clock

Counter

Q2 Q2 Q3

Note 1: TOST = 1024 TOSC; TPLL = 2 ms (approx). These intervals are not shown to scale.

Wake from Interrupt Event

TPLL(1)

12 n-1n

Clock

OSTS bit Set

Transition

TOST(1)

PIC18F87J50 FAMILY

25.4.1 SPECIAL CONSIDERATIONS FOR

USING TWO-SPEED START-UP

While using the INTRC oscillator in Two-Speed

Start-up, the device still obeys the normal command

sequences for entering power-managed modes,

including serial SLEEP instructions (refer to

Section 3.1.4 “Multiple Sleep Commands”). In prac-

tice, this means that user code can change the

SCS1:SCS0 bit settings or issue SLEEP instructions

before the OST times out. This would allow an applica-

tion to briefly wake-up, perform routine “housekeeping”

tasks and return to Sleep before the device starts to

operate from the primary oscillator.

User code can also check if the primary clock source is

currently providing the device clocking by checking the

status of the OSTS bit (OSCCON<3>). If the bit is set,

the primary oscillator is providing the clock. Otherwise,

the internal oscillator block is providing the clock during

wake-up from Reset or Sleep mode.

25.5 Fail-Safe Clock Monitor

The Fail-Safe Clock Monitor (FSCM) allows the

microcontroller to continue operation in the event of an

external oscillator failure by automatically switching the

device clock to the internal oscillator block. The FSCM

function is enabled by setting the FCMEN Configuration

bit.

When FSCM is enabled, the INTRC oscillator runs at

all times to monitor clocks to peripherals and provide a

backup clock in the event of a clock failure. Clock

monitoring (shown in Figure 25-4) is accomplished by

creating a sample clock signal which is the INTRC out-

put divided by 64. This allows ample time between

FSCM sample clocks for a peripheral clock edge to

occur. The peripheral device clock and the sample

clock are presented as inputs to the clock monitor latch.

The clock monitor is set on the falling edge of the

device clock source but cleared on the rising edge of

the sample clock.

FIGURE 25-4: FSCM BLOCK DIAGRAM

Clock failure is tested for on the falling edge of the

sample clock. If a sample clock falling edge occurs

while the clock monitor is still set, a clock failure has

been detected (Figure 25-5). This causes the following:

• the FSCM generates an oscillator fail interrupt by

setting bit OSCFIF (PIR2<7>);

• the device clock source is switched to the internal

oscillator block (OSCCON is not updated to show

the current clock source – this is the fail-safe

condition); and

• the WDT is reset.

During switchover, the postscaler frequency from the

internal oscillator block may not be sufficiently stable

for timing sensitive applications. In these cases, it may

be desirable to select another clock configuration and

enter an alternate power-managed mode. This can be

done to attempt a partial recovery or execute a

controlled shutdown. See Section 3.1.4 “Multiple

Sleep Commands” and Section 25.4.1 “Special

Considerations for Using Two-Speed Start-up” for

more details.

The FSCM will detect failures of the primary or second-

ary clock sources only. If the internal oscillator block

fails, no failure would be detected, nor would any action

be possible.

25.5.1 FSCM AND THE WATCHDOG TIMER

Both the FSCM and the WDT are clocked by the

INTRC oscillator. Since the WDT operates with a

separate divider and counter, disabling the WDT has

no effect on the operation of the INTRC oscillator when

the FSCM is enabled.

As already noted, the clock source is switched to the

INTRC clock when a clock failure is detected; this may

mean a substantial change in the speed of code execu-

tion. If the WDT is enabled with a small prescale value,

a decrease in clock speed allows a WDT time-out to

occur and a subsequent device Reset. For this reason,

fail-safe clock events also reset the WDT and

postscaler, allowing it to start timing from when execu-

tion speed was changed and decreasing the likelihood

of an erroneous time-out.

Peripheral

INTRC ÷ 64

(32 μs) 488 Hz

(2.048 ms)

Clock Monitor

Latch

(edge-triggered)

Clock

Failure

Detected

Source

Clock

PIC18F87J50 FAMILY

FIGURE 25-5: FSCM TIMING DIAGRAM

25.5.2 EXITING FAIL-SAFE OPERATION

The fail-safe condition is terminated by either a device

Reset or by entering a power-managed mode. On

Reset, the controller starts the primary clock source

specified in Configuration Register 2H (with any

required start-up delays that are required for the oscil-

lator mode, such as OST or PLL timer). The INTRC

oscillator provides the device clock until the primary

clock source becomes ready (similar to a Two-Speed

Start-up). The clock source is then switched to the

primary clock (indicated by the OSTS bit in the

OSCCON register becoming set). The Fail-Safe Clock

Monitor then resumes monitoring the peripheral clock.

The primary clock source may never become ready

during start-up. In this case, operation is clocked by the

INTRC oscillator. The OSCCON register will remain in

its Reset state until a power-managed mode is entered.

25.5.3 FSCM INTERRUPTS IN

POWER-MANAGED MODES

By entering a power-managed mode, the clock

multiplexor selects the clock source selected by the

OSCCON register. Fail-Safe Clock Monitoring of the

power-managed clock source resumes in the

power-managed mode.

If an oscillator failure occurs during power-managed

operation, the subsequent events depend on whether

or not the oscillator failure interrupt is enabled. If

enabled (OSCFIF = 1), code execution will be clocked

by the INTRC multiplexor. An automatic transition back

to the failed clock source will not occur.

If the interrupt is disabled, subsequent interrupts while

in Idle mode will cause the CPU to begin executing

instructions while being clocked by the INTRC source.

25.5.4 POR OR WAKE-UP FROM SLEEP

The FSCM is designed to detect oscillator failure at any

point after the device has exited Power-on Reset (POR)

or low-power Sleep mode. When the primary device

clock is either the EC or INTRC modes, monitoring can

begin immediately following these events.

For HS or HSPLL modes, the situation is somewhat

different. Since the oscillator may require a start-up

time considerably longer than the FSCM sample clock

time, a false clock failure may be detected. To prevent

this, the internal oscillator block is automatically config-

ured as the device clock and functions until the primary

clock is stable (the OST and PLL timers have timed

out). This is identical to Two-Speed Start-up mode.

Once the primary clock is stable, the INTRC returns to

its role as the FSCM source.

As noted in Section 25.4.1 “Special Considerations

for Using Two-Speed Start-up”, it is also possible to

select another clock configuration and enter an alternate

power-managed mode while waiting for the primary

clock to become stable. When the new power-managed

mode is selected, the primary clock is disabled.

OSCFIF

Clock Monitor

Device

Clock

Output

Sample Clock

Failure

Detected

Oscillator

Failure

Note: The device clock is normally at a much higher frequency than the sample clock. The relative frequencies in

this example have been chosen for clarity.

Output (Q)

Clock Monitor Test Clock Monitor Test Clock Monitor Test

Note: The same logic that prevents false oscilla-

tor failure interrupts on POR, or wake from

Sleep, will also prevent the detection of

the oscillator’s failure to start at all follow-

ing these events. This can be avoided by

monitoring the OSTS bit and using a

timing routine to determine if the oscillator

is taking too long to start. Even so, no

oscillator failure interrupt will be flagged.

PIC18F87J50 FAMILY

25.6 Program Verification and

Code Protection

For all devices in the PIC18F87J10 family of devices,

the on-chip program memory space is treated as a

single block. Code protection for this block is controlled

by one Configuration bit, CP0. This bit inhibits external

reads and writes to the program memory space. It has

no direct effect in normal execution mode.

25.6.1 CONFIGURATION REGISTER

PROTECTION

The Configuration registers are protected against

untoward changes or reads in two ways. The primary

protection is the write-once feature of the Configuration

bits which prevents reconfiguration once the bit has

been programmed during a power cycle. To safeguard

against unpredictable events, Configuration bit

changes resulting from individual cell level disruptions

(such as ESD events) will cause a parity error and

trigger a device Reset. This is seen by the user as a

Configuration Mismatch (CM) Reset.

The data for the Configuration registers is derived from

the Flash Configuration Words in program memory.

When the CP0 bit set, the source data for device

configuration is also protected as a consequence.

25.7 In-Circuit Serial Programming

PIC18F87J10 family microcontrollers can be serially

programmed while in the end application circuit. This is

simply done with two lines for clock and data and three

other lines for power, ground and the programming

voltage. This allows customers to manufacture boards

with unprogrammed devices and then program the

microcontroller just before shipping the product. This

also allows the most recent firmware or a custom

firmware to be programmed.

25.8 In-Circuit Debugger

When the DEBUG Configuration bit is programmed to

a ‘0’, the In-Circuit Debugger functionality is enabled.

This function allows simple debugging functions when

used with MPLAB® IDE. When the microcontroller has

this feature enabled, some resources are not available

for general use. Table 25-4 shows which resources are

required by the background debugger.

TABLE 25-4: DEBUGGER RESOURCES

I/O pins: RB6, RB7

Stack: 2 levels

Program Memory: 512 bytes

Data Memory: 10 bytes

PIC18F87J50 FAMILY

26.0 INSTRUCTION SET SUMMARY

The PIC18F87J10 family of devices incorporate the

standard set of 75 PIC18 core instructions, as well as

an extended set of 8 new instructions for the optimiza-

tion of code that is recursive or that utilizes a software

stack. The extended set is discussed later in this

section.

26.1 Standard Instruction Set

The standard PIC18 instruction set adds many

enhancements to the previous PIC® instruction sets,

while maintaining an easy migration from these PIC

instruction sets. Most instructions are a single program

memory word (16 bits), but there are four instructions

that require two program memory locations.

Each single-word instruction is a 16-bit word divided

into an opcode, which specifies the instruction type and

one or more operands, which further specify the

operation of the instruction.

The instruction set is highly orthogonal and is grouped

into four basic categories:

•Byte-oriented operations

•Bit-oriented operations

•Literal operations

•Control operations

The PIC18 instruction set summary in Table 26-2 lists

byte-oriented, bit-oriented, literal and control

operations. Table 26-1 shows the opcode field

descriptions.

Most byte-oriented instructions have three operands:

1. The file register (specified by ‘f’)

2. The destination of the result (specified by ‘d’)

3. The accessed memory (specified by ‘a’)

The file register designator, ‘f’, specifies which file

designator, ‘d’, specifies where the result of the

operation is to be placed. If ‘d’ is ‘0’, the result is placed

in the WREG register. If ‘d’ is ‘1’, the result is placed in

the file register specified in the instruction.

All bit-oriented instructions have three operands:

1. The file register (specified by ‘f’)

2. The bit in the file register (specified by ‘b’)

3. The accessed memory (specified by ‘a’)

The bit field designator ‘b’ selects the number of the bit

affected by the operation, while the file register desig-

nator, ‘f’, represents the number of the file in which the

bit is located.

The literal instructions may use some of the following

operands:

• A literal value to be loaded into a file register

(specified by ‘k’)

• The desired FSR register to load the literal value

into (specified by ‘f’)

• No operand required

(specified by ‘—’)

The control instructions may use some of the following

operands:

• A program memory address (specified by ‘n’)

• The mode of the CALL or RETURN instructions

(specified by ‘s’)

• The mode of the table read and table write

instructions (specified by ‘m’)

• No operand required

(specified by ‘—’)

All instructions are a single word, except for four

double-word instructions. These instructions were

made double-word to contain the required information

in 32 bits. In the second word, the 4 MSbs are ‘1’s. If

this second word is executed as an instruction (by

itself), it will execute as a NOP.

All single-word instructions are executed in a single

instruction cycle, unless a conditional test is true or the

program counter is changed as a result of the instruc-

tion. In these cases, the execution takes two instruction

cycles with the additional instruction cycle(s) executed

as a NOP.

The double-word instructions execute in two instruction

cycles.

One instruction cycle consists of four oscillator periods.

Thus, for an oscillator frequency of 4 MHz, the normal

instruction execution time is 1 μs. If a conditional test is

true, or the program counter is changed as a result of

an instruction, the instruction execution time is 2 μs.

Two-word branch instructions (if true) would take 3 μs.

Figure 26-1 shows the general formats that the instruc-

tions can have. All examples use the convention ‘nnh’

to represent a hexadecimal number.

The instruction set summary, shown in Table 26-2, lists

the standard instructions recognized by the Microchip

MPASMTM Assembler.

Section 26.1.1 “Standard Instruction Set” provides

a description of each instruction.

PIC18F87J50 FAMILY

TABLE 26-1: OPCODE FIELD DESCRIPTIONS

Field Description

aRAM access bit:

a = 0: RAM location in Access RAM (BSR register is ignored)

a = 1: RAM bank is specified by BSR register

bbb Bit address within an 8-bit file register (0 to 7).

BSR Bank Select Register. Used to select the current RAM bank.

C, DC, Z, OV, N ALU Status bits: Carry, Digit Carry, Zero, Overflow, Negative.

dDestination select bit:

d = 0: store result in WREG

d = 1: store result in file register f

dest Destination: either the WREG register or the specified register file location.

f8-bit register file address (00h to FFh), or 2-bit FSR designator (0h to 3h).

fs12-bit register file address (000h to FFFh). This is the source address.

fd12-bit register file address (000h to FFFh). This is the destination address.

GIE Global Interrupt Enable bit.

kLiteral field, constant data or label (may be either an 8-bit, 12-bit or a 20-bit value).

label Label name.

mm The mode of the TBLPTR register for the table read and table write instructions.

Only used with table read and table write instructions:

*No Change to register (such as TBLPTR with table reads and writes)

*+ Post-Increment register (such as TBLPTR with table reads and writes)

*- Post-Decrement register (such as TBLPTR with table reads and writes)

+* Pre-Increment register (such as TBLPTR with table reads and writes)

nThe relative address (2’s complement number) for relative branch instructions or the direct address for

Call/Branch and Return instructions.

PC Program Counter.

PCL Program Counter Low Byte.

PCH Program Counter High Byte.

PCLATH Program Counter High Byte Latch.

PCLATU Program Counter Upper Byte Latch.

PD Power-Down bit.

PRODH Product of Multiply High Byte.

PRODL Product of Multiply Low Byte.

sFast Call/Return mode select bit:

s = 0: do not update into/from shadow registers

s = 1: certain registers loaded into/from shadow registers (Fast mode)

TBLPTR 21-Bit Table Pointer (points to a program memory location).

TABLAT 8-Bit Table Latch.

TO Time-out bit.

TOS Top-of-Stack.

uUnused or Unchanged.

WDT Watchdog Timer.

WREG Working register (accumulator).

xDon’t care (‘0’ or ‘1’). The assembler will generate code with x = 0. It is the recommended form of use for

compatibility with all Microchip software tools.

zs7-bit offset value for Indirect Addressing of register files (source).

zd7-bit offset value for Indirect Addressing of register files (destination).

{ } Optional argument.

[text] Indicates Indexed Addressing.

(text) The contents of text.

[expr]<n> Specifies bit n of the register indicated by the pointer, expr.

→Assigned to.

< > Register bit field.

∈In the set of.

italics User-defined term (font is Courier New).

PIC18F87J50 FAMILY

FIGURE 26-1: GENERAL FORMAT FOR INSTRUCTIONS

Byte-oriented file register operations

15 10 9 8 7 0

d = 0 for result destination to be WREG register

OPCODE d a f (FILE #)

d = 1 for result destination to be file register (f)

a = 0 to force Access Bank

Bit-oriented file register operations

15 12 11 9 8 7 0

OPCODE b (BIT #) a f (FILE #)

b = 3-bit position of bit in file register (f)

Literal operations

15 8 7 0

OPCODE k (literal)

k = 8-bit immediate value

Byte to Byte move operations (2-word)

15 12 11 0

OPCODE f (Source FILE #)

CALL, GOTO and Branch operations

15 8 7 0

OPCODE n<7:0> (literal)

n = 20-bit immediate value

a = 1 for BSR to select bank

f = 8-bit file register address

a = 0 to force Access Bank

a = 1 for BSR to select bank

f = 8-bit file register address

15 12 11 0

1111 n<19:8> (literal)

15 12 11 0

1111 f (Destination FILE #)

f = 12-bit file register address

Control operations

Example Instruction

ADDWF MYREG, W, B

MOVFF MYREG1, MYREG2

BSF MYREG, bit, B

MOVLW 7Fh

GOTO Label

15 8 7 0

OPCODE n<7:0> (literal)

15 12 11 0

1111 n<19:8> (literal)

CALL MYFUNC

15 11 10 0

OPCODE n<10:0> (literal)

S = Fast bit

BRA MYFUNC

15 8 7 0

OPCODE n<7:0> (literal) BC MYFUNC

PIC18F87J50 FAMILY

TABLE 26-2: PIC18F87J50 FAMILY INSTRUCTION SET

Mnemonic,

Operands Description Cycles

16-Bit Instruction Word Status

Affected Notes

MSb LSb

BYTE-ORIENTED OPERATIONS

ADDWF

ADDWFC

ANDWF

CLRF

COMF

CPFSEQ

CPFSGT

CPFSLT

DECF

DECFSZ

DCFSNZ

INCF

INCFSZ

INFSNZ

IORWF

MOVF

MOVFF

MOVWF

MULWF

NEGF

RLCF

RLNCF

RRCF

RRNCF

SETF

SUBFWB

SUBWF

SUBWFB

SWAPF

TSTFSZ

XORWF

f, d, a

f, a

f, d, a

f, a

f, d, a

fs, fd

f, a

f, d, a

f, a

f, d, a

f, a

f, d, a

Add WREG and f

Add WREG and Carry bit to f

AND WREG with f

Clear f

Complement f

Compare f with WREG, Skip =

Compare f with WREG, Skip >

Compare f with WREG, Skip <

Decrement f

Decrement f, Skip if 0

Decrement f, Skip if Not 0

Increment f

Increment f, Skip if 0

Increment f, Skip if Not 0

Inclusive OR WREG with f

Move f

Move fs (source) to 1st word

fd (destination) 2nd word

Move WREG to f

Multiply WREG with f

Negate f

Rotate Left f through Carry

Rotate Left f (No Carry)

Rotate Right f through Carry

Rotate Right f (No Carry)

Set f

Subtract f from WREG with

Borrow

Subtract WREG from f

Subtract WREG from f with

Borrow

Swap Nibbles in f

Test f, Skip if 0

Exclusive OR WREG with f

1 (2 or 3)

0010

0001

0110

0001

0110

0000

0010

0100

0010

0011

0100

0001

0101

1100

1111

0110

0000

0110

0011

0100

0011

0100

0110

0101

0011

0110

0001

01da

00da

01da

101a

11da

001a

010a

000a

01da

11da

10da

11da

10da

00da

ffff

111a

001a

110a

01da

00da

100a

01da

11da

10da

011a

10da

ffff

C, DC, Z, OV, N

Z, N

None

C, DC, Z, OV, N

None

C, DC, Z, OV, N

None

Z, N

None

C, DC, Z, OV, N

C, Z, N

Z, N

C, Z, N

Z, N

None

C, DC, Z, OV, N

None

Z, N

1, 2

1,2

1, 2

1, 2, 3, 4

1, 2

1, 2, 3, 4

1, 2

Note 1: When a PORT register is modified as a function of itself (e.g., MOVF PORTB, 1, 0), the value used will be that

value present on the pins themselves. For example, if the data latch is ‘1’ for a pin configured as input and is

driven low by an external device, the data will be written back with a ‘0’.

2: If this instruction is executed on the TMR0 register (and, where applicable, d = 1), the prescaler will be cleared

if assigned.

3: If the Program Counter (PC) is modified or a conditional test is true, the instruction requires two cycles. The

second cycle is executed as a NOP.

4: Some instructions are two-word instructions. The second word of these instructions will be executed as a NOP

unless the first word of the instruction retrieves the information embedded in these 16 bits. This ensures that all

program memory locations have a valid instruction.

PIC18F87J50 FAMILY

BIT-ORIENTED OPERATIONS

BCF

BSF

BTFSC

BTFSS

BTG

f, b, a

Bit Clear f

Bit Set f

Bit Test f, Skip if Clear

Bit Test f, Skip if Set

Bit Toggle f

1 (2 or 3)

1001

1000

1011

1010

0111

bbba

ffff

None

1, 2

3, 4

1, 2

CONTROL OPERATIONS

BNC

BNN

BNOV

BNZ

BOV

BRA

CALL

CLRWDT

DAW

GOTO

NOP

POP

PUSH

RCALL

RESET

RETFIE

RETLW

RETURN

SLEEP

n, s

—

Branch if Carry

Branch if Negative

Branch if Not Carry

Branch if Not Negative

Branch if Not Overflow

Branch if Not Zero

Branch if Overflow

Branch Unconditionally

Branch if Zero

Call Subroutine 1st word

2nd word

Clear Watchdog Timer

Decimal Adjust WREG

Go to Address 1st word

2nd word

No Operation

Pop Top of Return Stack (TOS)

Push Top of Return Stack (TOS)

Relative Call

Software Device Reset

Return from Interrupt Enable

Return with Literal in WREG

Return from Subroutine

Go into Standby mode

1 (2)

1110

1101

1110

1111

0000

1110

1111

0000

1111

0000

1101

0000

0010

0110

0011

0111

0101

0001

0100

0nnn

0000

110s

kkkk

0000

1111

kkkk

0000

xxxx

0000

1nnn

0000

1100

0000

nnnn

kkkk

0000

kkkk

0000

xxxx

0000

nnnn

1111

0001

kkkk

0001

0000

nnnn

kkkk

0100

0111

kkkk

0000

xxxx

0110

0101

nnnn

1111

000s

kkkk

001s

0011

None

TO, PD

None

All

GIE/GIEH,

PEIE/GIEL

None

TO, PD

TABLE 26-2: PIC18F87J50 FAMILY INSTRUCTION SET (CONTINUED)

Mnemonic,

Operands Description Cycles

16-Bit Instruction Word Status

Affected Notes

MSb LSb

Note 1: When a PORT register is modified as a function of itself (e.g., MOVF PORTB, 1, 0), the value used will be that

value present on the pins themselves. For example, if the data latch is ‘1’ for a pin configured as input and is

driven low by an external device, the data will be written back with a ‘0’.

2: If this instruction is executed on the TMR0 register (and, where applicable, d = 1), the prescaler will be cleared

if assigned.

3: If the Program Counter (PC) is modified or a conditional test is true, the instruction requires two cycles. The

second cycle is executed as a NOP.

4: Some instructions are two-word instructions. The second word of these instructions will be executed as a NOP

unless the first word of the instruction retrieves the information embedded in these 16 bits. This ensures that all

program memory locations have a valid instruction.

PIC18F87J50 FAMILY

LITERAL OPERATIONS

ADDLW

ANDLW

IORLW

LFSR

MOVLB

MOVLW

MULLW

RETLW

SUBLW

XORLW

f, k

Add Literal and WREG

AND Literal with WREG

Inclusive OR Literal with WREG

Move Literal (12-bit) 2nd word

to FSR(f) 1st word

Move Literal to BSR<3:0>

Move Literal to WREG

Multiply Literal with WREG

Return with Literal in WREG

Subtract WREG from Literal

Exclusive OR Literal with WREG

0000

1110

1111

0000

1111

1011

1001

1110

0000

0001

1110

1101

1100

1000

1010

kkkk

00ff

kkkk

0000

kkkk

C, DC, Z, OV, N

Z, N

None

C, DC, Z, OV, N

Z, N

DATA MEMORY ↔ PROGRAM MEMORY OPERATIONS

TBLRD*

TBLRD*+

TBLRD*-

TBLRD+*

TBLWT*

TBLWT*+

TBLWT*-

TBLWT+*

Table Read

Table Read with Post-Increment

Table Read with Post-Decrement

Table Read with Pre-Increment

Table Write

Table Write with Post-Increment

Table Write with Post-Decrement

Table Write with Pre-Increment

0000

1000

1001

1010

1011

1100

1101

1110

1111

None

TABLE 26-2: PIC18F87J50 FAMILY INSTRUCTION SET (CONTINUED)

Mnemonic,

Operands Description Cycles

16-Bit Instruction Word Status

Affected Notes

MSb LSb

Note 1: When a PORT register is modified as a function of itself (e.g., MOVF PORTB, 1, 0), the value used will be that

value present on the pins themselves. For example, if the data latch is ‘1’ for a pin configured as input and is

driven low by an external device, the data will be written back with a ‘0’.

2: If this instruction is executed on the TMR0 register (and, where applicable, d = 1), the prescaler will be cleared

if assigned.

3: If the Program Counter (PC) is modified or a conditional test is true, the instruction requires two cycles. The

second cycle is executed as a NOP.

4: Some instructions are two-word instructions. The second word of these instructions will be executed as a NOP

unless the first word of the instruction retrieves the information embedded in these 16 bits. This ensures that all

program memory locations have a valid instruction.

PIC18F87J50 FAMILY

26.1.1 STANDARD INSTRUCTION SET

ADDLW ADD Literal to W

Syntax: ADDLW k

Operands: 0 ≤ k ≤ 255

Operation: (W) + k → W

Status Affected: N, OV, C, DC, Z

Encoding: 0000 1111 kkkk kkkk

Description: The contents of W are added to the

8-bit literal ‘k’ and the result is placed in

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

literal ‘k’

Process

Data

Write to

Example: ADDLW 15h

Before Instruction

W = 10h

After Instruction

W = 25h

ADDWF ADD W to f

Syntax: ADDWF f {,d {,a}}

Operands: 0 ≤ f ≤ 255

d ∈ [0,1]

a ∈ [0,1]

Operation: (W) + (f) → dest

Status Affected: N, OV, C, DC, Z

Encoding: 0010 01da ffff ffff

Description: Add W to register ‘f’. If ‘d’ is ‘0’, the

result is stored in W. If ‘d’ is ‘1’, the

result is stored back in register ‘f’

(default).

If ‘a’ is ‘0’, the Access Bank is selected.

If ‘a’ is ‘1’, the BSR is used to select the

GPR bank (default).

If ‘a’ is ‘0’ and the extended instruction

set is enabled, this instruction operates

in Indexed Literal Offset Addressing

mode whenever f ≤ 95 (5Fh). See

Section 26.2.3 “Byte-Oriented and

Bit-Oriented Instructions in Indexed

Literal Offset Mode” for details.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

Process

Data

Write to

destination

Example: ADDWF REG, 0, 0

Before Instruction

W = 17h

REG = 0C2h

After Instruction

W = 0D9h

REG = 0C2h

Note: All PIC18 instructions may take an optional label argument preceding the instruction mnemonic for use in

symbolic addressing. If a label is used, the instruction format then becomes: {label} instruction argument(s).

PIC18F87J50 FAMILY

ADDWFC ADD W and Carry bit to f

Syntax: ADDWFC f {,d {,a}}

Operands: 0 ≤ f ≤ 255

d ∈ [0,1]

a ∈ [0,1]

Operation: (W) + (f) + (C) → dest

Status Affected: N,OV, C, DC, Z

Encoding: 0010 00da ffff ffff

Description: Add W, the Carry flag and data memory

location ‘f’. If ‘d’ is ‘0’, the result is

placed in W. If ‘d’ is ‘1’, the result is

placed in data memory location ‘f’.

If ‘a’ is ‘0’, the Access Bank is selected.

If ‘a’ is ‘1’, the BSR is used to select the

GPR bank (default).

If ‘a’ is ‘0’ and the extended instruction

set is enabled, this instruction operates

in Indexed Literal Offset Addressing

mode whenever f ≤ 95 (5Fh). See

Section 26.2.3 “Byte-Oriented and

Bit-Oriented Instructions in Indexed

Literal Offset Mode” for details.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

Process

Data

Write to

destination

Example: ADDWFC REG, 0, 1

Before Instruction

Carry bit = 1

REG = 02h

W=4Dh

After Instruction

Carry bit = 0

REG = 02h

W = 50h

ANDLW AND Literal with W

Syntax: ANDLW k

Operands: 0 ≤ k ≤ 255

Operation: (W) .AND. k → W

Status Affected: N, Z

Encoding: 0000 1011 kkkk kkkk

Description: The contents of W are ANDed with the

8-bit literal ‘k’. The result is placed in W.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read literal

‘k’

Process

Data

Write to

Example: ANDLW 05Fh

Before Instruction

W=A3h

After Instruction

W = 03h

PIC18F87J50 FAMILY

ANDWF AND W with f

Syntax: ANDWF f {,d {,a}}

Operands: 0 ≤ f ≤ 255

d ∈ [0,1]

a ∈ [0,1]

Operation: (W) .AND. (f) → dest

Status Affected: N, Z

Encoding: 0001 01da ffff ffff

Description: The contents of W are ANDed with

in W. If ‘d’ is ‘1’, the result is stored back

in register ‘f’ (default).

If ‘a’ is ‘0’, the Access Bank is selected.

If ‘a’ is ‘1’, the BSR is used to select the

GPR bank (default).

If ‘a’ is ‘0’ and the extended instruction

set is enabled, this instruction operates

in Indexed Literal Offset Addressing

mode whenever f ≤ 95 (5Fh). See

Section 26.2.3 “Byte-Oriented and

Bit-Oriented Instructions in Indexed

Literal Offset Mode” for details.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

Process

Data

Write to

destination

Example: ANDWF REG, 0, 0

Before Instruction

W = 17h

REG = C2h

After Instruction

W = 02h

REG = C2h

BC Branch if Carry

Syntax: BC n

Operands: -128 ≤ n ≤ 127

Operation: if Carry bit is ‘1’,

(PC) + 2 + 2n → PC

Status Affected: None

Encoding: 1110 0010 nnnn nnnn

Description: If the Carry bit is ’1’, then the program

will branch.

The 2’s complement number ‘2n’ is

added to the PC. Since the PC will have

incremented to fetch the next

instruction, the new address will be

PC + 2 + 2n. This instruction is then a

two-cycle instruction.

Words: 1

Cycles: 1(2)

Q Cycle Activity:

If Jump:

Q1 Q2 Q3 Q4

Decode Read literal

‘n’

Process

Data

Write to

operation

If No Jump:

Q1 Q2 Q3 Q4

Decode Read literal

‘n’

Process

Data

operation

Example: HERE BC 5

Before Instruction

PC = address (HERE)

After Instruction

If Carry = 1;

PC = address (HERE + 12)

If Carry = 0;

PC = address (HERE + 2)

PIC18F87J50 FAMILY

BCF Bit Clear f

Syntax: BCF f, b {,a}

Operands: 0 ≤ f ≤ 255

0 ≤ b ≤ 7

a ∈ [0,1]

Operation: 0 → f

Status Affected: None

Encoding: 1001 bbba ffff ffff

Description: Bit ‘b’ in register ‘f’ is cleared.

If ‘a’ is ‘0’, the Access Bank is selected.

If ‘a’ is ‘1’, the BSR is used to select the

GPR bank (default).

If ‘a’ is ‘0’ and the extended instruction

set is enabled, this instruction operates

in Indexed Literal Offset Addressing

mode whenever f ≤ 95 (5Fh). See

Section 26.2.3 “Byte-Oriented and

Bit-Oriented Instructions in Indexed

Literal Offset Mode” for details.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

Process

Data

Write

Example: BCF FLAG_REG, 7, 0

Before Instruction

FLAG_REG = C7h

After Instruction

FLAG_REG = 47h

BN Branch if Negative

Syntax: BN n

Operands: -128 ≤ n ≤ 127

Operation: if Negative bit is ‘1’,

(PC) + 2 + 2n → PC

Status Affected: None

Encoding: 1110 0110 nnnn nnnn

Description: If the Negative bit is ‘1’, then the

program will branch.

The 2’s complement number ‘2n’ is

added to the PC. Since the PC will have

incremented to fetch the next

instruction, the new address will be

PC + 2 + 2n. This instruction is then a

two-cycle instruction.

Words: 1

Cycles: 1(2)

Q Cycle Activity:

If Jump:

Q1 Q2 Q3 Q4

Decode Read literal

‘n’

Process

Data

Write to

operation

If No Jump:

Q1 Q2 Q3 Q4

Decode Read literal

‘n’

Process

Data

operation

Example: HERE BN Jump

Before Instruction

PC = address (HERE)

After Instruction

If Negative = 1;

PC = address (Jump)

If Negative = 0;

PC = address (HERE + 2)

PIC18F87J50 FAMILY

BNC Branch if Not Carry

Syntax: BNC n

Operands: -128 ≤ n ≤ 127

Operation: if Carry bit is ‘0’,

(PC) + 2 + 2n → PC

Status Affected: None

Encoding: 1110 0011 nnnn nnnn

Description: If the Carry bit is ‘0’, then the program

will branch.

The 2’s complement number ‘2n’ is

added to the PC. Since the PC will have

incremented to fetch the next

instruction, the new address will be

PC + 2 + 2n. This instruction is then a

two-cycle instruction.

Words: 1

Cycles: 1(2)

Q Cycle Activity:

If Jump:

Q1 Q2 Q3 Q4

Decode Read literal

‘n’

Process

Data

Write to

operation

If No Jump:

Q1 Q2 Q3 Q4

Decode Read literal

‘n’

Process

Data

operation

Example: HERE BNC Jump

Before Instruction

PC = address (HERE)

After Instruction

If Carry = 0;

PC = address (Jump)

If Carry = 1;

PC = address (HERE + 2)

BNN Branch if Not Negative

Syntax: BNN n

Operands: -128 ≤ n ≤ 127

Operation: if Negative bit is ‘0’,

(PC) + 2 + 2n → PC

Status Affected: None

Encoding: 1110 0111 nnnn nnnn

Description: If the Negative bit is ‘0’, then the

program will branch.

The 2’s complement number ‘2n’ is

added to the PC. Since the PC will have

incremented to fetch the next

instruction, the new address will be

PC + 2 + 2n. This instruction is then a

two-cycle instruction.

Words: 1

Cycles: 1(2)

Q Cycle Activity:

If Jump:

Q1 Q2 Q3 Q4

Decode Read literal

‘n’

Process

Data

Write to

operation

If No Jump:

Q1 Q2 Q3 Q4

Decode Read literal

‘n’

Process

Data

operation

Example: HERE BNN Jump

Before Instruction

PC = address (HERE)

After Instruction

If Negative = 0;

PC = address (Jump)

If Negative = 1;

PC = address (HERE + 2)

PIC18F87J50 FAMILY

BNOV Branch if Not Overflow

Syntax: BNOV n

Operands: -128 ≤ n ≤ 127

Operation: if Overflow bit is ‘0’,

(PC) + 2 + 2n → PC

Status Affected: None

Encoding: 1110 0101 nnnn nnnn

Description: If the Overflow bit is ‘0’, then the

program will branch.

The 2’s complement number ‘2n’ is

added to the PC. Since the PC will have

incremented to fetch the next

instruction, the new address will be

PC + 2 + 2n. This instruction is then a

two-cycle instruction.

Words: 1

Cycles: 1(2)

Q Cycle Activity:

If Jump:

Q1 Q2 Q3 Q4

Decode Read literal

‘n’

Process

Data

Write to

operation

If No Jump:

Q1 Q2 Q3 Q4

Decode Read literal

‘n’

Process

Data

operation

Example: HERE BNOV Jump

Before Instruction

PC = address (HERE)

After Instruction

If Overflow = 0;

PC = address (Jump)

If Overflow = 1;

PC = address (HERE + 2)

BNZ Branch if Not Zero

Syntax: BNZ n

Operands: -128 ≤ n ≤ 127

Operation: if Zero bit is ‘0’,

(PC) + 2 + 2n → PC

Status Affected: None

Encoding: 1110 0001 nnnn nnnn

Description: If the Zero bit is ‘0’, then the program

will branch.

The 2’s complement number ‘2n’ is

added to the PC. Since the PC will have

incremented to fetch the next

instruction, the new address will be

PC + 2 + 2n. This instruction is then a

two-cycle instruction.

Words: 1

Cycles: 1(2)

Q Cycle Activity:

If Jump:

Q1 Q2 Q3 Q4

Decode Read literal

‘n’

Process

Data

Write to

operation

If No Jump:

Q1 Q2 Q3 Q4

Decode Read literal

‘n’

Process

Data

operation

Example: HERE BNZ Jump

Before Instruction

PC = address (HERE)

After Instruction

If Zero = 0;

PC = address (Jump)

If Zero = 1;

PC = address (HERE + 2)

PIC18F87J50 FAMILY

BRA Unconditional Branch

Syntax: BRA n

Operands: -1024 ≤ n ≤ 1023

Operation: (PC) + 2 + 2n → PC

Status Affected: None

Encoding: 1101 0nnn nnnn nnnn

Description: Add the 2’s complement number ‘2n’ to

the PC. Since the PC will have

incremented to fetch the next

instruction, the new address will be

PC + 2 + 2n. This instruction is a

two-cycle instruction.

Words: 1

Cycles: 2

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read literal

‘n’

Process

Data

Write to

operation

Example: HERE BRA Jump

Before Instruction

PC = address (HERE)

After Instruction

PC = address (Jump)

BSF Bit Set f

Syntax: BSF f, b {,a}

Operands: 0 ≤ f ≤ 255

0 ≤ b ≤ 7

a ∈ [0,1]

Operation: 1 → f

Status Affected: None

Encoding: 1000 bbba ffff ffff

Description: Bit ‘b’ in register ‘f’ is set.

If ‘a’ is ‘0’, the Access Bank is selected.

If ‘a’ is ‘1’, the BSR is used to select the

GPR bank (default).

If ‘a’ is ‘0’ and the extended instruction

set is enabled, this instruction operates

in Indexed Literal Offset Addressing

mode whenever f ≤ 95 (5Fh). See

Section 26.2.3 “Byte-Oriented and

Bit-Oriented Instructions in Indexed

Literal Offset Mode” for details.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

Process

Data

Write

Example: BSF FLAG_REG, 7, 1

Before Instruction

FLAG_REG = 0Ah

After Instruction

FLAG_REG = 8Ah

PIC18F87J50 FAMILY

BTFSC Bit Test File, Skip if Clear

Syntax: BTFSC f, b {,a}

Operands: 0 ≤ f ≤ 255

0 ≤ b ≤ 7

a ∈ [0,1]

Operation: skip if (f) = 0

Status Affected: None

Encoding: 1011 bbba ffff ffff

Description: If bit ‘b’ in register ‘f’ is ‘0’, then the next

instruction is skipped. If bit ‘b’ is ‘0’, then

the next instruction fetched during the

current instruction execution is discarded

and a NOP is executed instead, making

this a two-cycle instruction.

If ‘a’ is ‘0’, the Access Bank is selected. If

‘a’ is ‘1’, the BSR is used to select the

GPR bank (default).

If ‘a’ is ‘0’ and the extended instruction set

is enabled, this instruction operates in

Indexed Literal Offset Addressing mode

whenever f ≤ 95 (5Fh). See

Section 26.2.3 “Byte-Oriented and

Bit-Oriented Instructions in Indexed

Literal Offset Mode” for details.

Words: 1

Cycles: 1(2)

Note: 3 cycles if skip and followed

by a 2-word instruction.

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

Process

Data

operation

If skip:

Q1 Q2 Q3 Q4

operation

If skip and followed by 2-word instruction:

Q1 Q2 Q3 Q4

operation

Example: HERE

FALSE

TRUE

BTFSC

FLAG, 1, 0

Before Instruction

PC = address (HERE)

After Instruction

If FLAG<1> = 0;

PC = address (TRUE)

If FLAG<1> = 1;

PC = address (FALSE)

BTFSS Bit Test File, Skip if Set

Syntax: BTFSS f, b {,a}

Operands: 0 ≤ f ≤ 255

0 ≤ b < 7

a ∈ [0,1]

Operation: skip if (f) = 1

Status Affected: None

Encoding: 1010 bbba ffff ffff

Description: If bit ‘b’ in register ‘f’ is ‘1’, then the next

instruction is skipped. If bit ‘b’ is ‘1’, then

the next instruction fetched during the

current instruction execution is discarded

and a NOP is executed instead, making

this a two-cycle instruction.

If ‘a’ is ‘0’, the Access Bank is selected. If

‘a’ is ‘1’, the BSR is used to select the

GPR bank (default).

If ‘a’ is ‘0’ and the extended instruction

set is enabled, this instruction operates in

Indexed Literal Offset Addressing mode

whenever f ≤ 95 (5Fh). See

Section 26.2.3 “Byte-Oriented and

Bit-Oriented Instructions in Indexed

Literal Offset Mode” for details.

Words: 1

Cycles: 1(2)

Note: 3 cycles if skip and followed

by a 2-word instruction.

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

Process

Data

operation

If skip:

Q1 Q2 Q3 Q4

operation

If skip and followed by 2-word instruction:

Q1 Q2 Q3 Q4

operation

Example: HERE

FALSE

TRUE

BTFSS

FLAG, 1, 0

Before Instruction

PC = address (HERE)

After Instruction

If FLAG<1> = 0;

PC = address (FALSE)

If FLAG<1> = 1;

PC = address (TRUE)

PIC18F87J50 FAMILY

BTG Bit Toggle f

Syntax: BTG f, b {,a}

Operands: 0 ≤ f ≤ 255

0 ≤ b < 7

a ∈ [0,1]

Operation: (f) → f

Status Affected: None

Encoding: 0111 bbba ffff ffff

Description: Bit ‘b’ in data memory location ‘f’ is

inverted.

If ‘a’ is ‘0’, the Access Bank is selected.

If ‘a’ is ‘1’, the BSR is used to select the

GPR bank (default).

If ‘a’ is ‘0’ and the extended instruction

set is enabled, this instruction operates

in Indexed Literal Offset Addressing

mode whenever f ≤ 95 (5Fh). See

Section 26.2.3 “Byte-Oriented and

Bit-Oriented Instructions in Indexed

Literal Offset Mode” for details.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

Process

Data

Write

Example: BTG PORTC, 4, 0

Before Instruction:

PORTC = 0111 0101 [75h]

After Instruction:

PORTC = 0110 0101 [65h]

BOV Branch if Overflow

Syntax: BOV n

Operands: -128 ≤ n ≤ 127

Operation: if Overflow bit is ‘1’,

(PC) + 2 + 2n → PC

Status Affected: None

Encoding: 1110 0100 nnnn nnnn

Description: If the Overflow bit is ‘1’, then the

program will branch.

The 2’s complement number ‘2n’ is

added to the PC. Since the PC will have

incremented to fetch the next

instruction, the new address will be

PC + 2 + 2n. This instruction is then a

two-cycle instruction.

Words: 1

Cycles: 1(2)

Q Cycle Activity:

If Jump:

Q1 Q2 Q3 Q4

Decode Read literal

‘n’

Process

Data

Write to PC

operation

If No Jump:

Q1 Q2 Q3 Q4

Decode Read literal

‘n’

Process

Data

operation

Example: HERE BOV Jump

Before Instruction

PC = address (HERE)

After Instruction

If Overflow = 1;

PC = address (Jump)

If Overflow = 0;

PC = address (HERE + 2)

PIC18F87J50 FAMILY

BZ Branch if Zero

Syntax: BZ n

Operands: -128 ≤ n ≤ 127

Operation: if Zero bit is ‘1’,

(PC) + 2 + 2n → PC

Status Affected: None

Encoding: 1110 0000 nnnn nnnn

Description: If the Zero bit is ‘1’, then the program

will branch.

The 2’s complement number ‘2n’ is

added to the PC. Since the PC will have

incremented to fetch the next

instruction, the new address will be

PC + 2 + 2n. This instruction is then a

two-cycle instruction.

Words: 1

Cycles: 1(2)

Q Cycle Activity:

If Jump:

Q1 Q2 Q3 Q4

Decode Read literal

‘n’

Process

Data

Write to

operation

If No Jump:

Q1 Q2 Q3 Q4

Decode Read literal

‘n’

Process

Data

operation

Example: HERE BZ Jump

Before Instruction

PC = address (HERE)

After Instruction

If Zero = 1;

PC = address (Jump)

If Zero = 0;

PC = address (HERE + 2)

CALL Subroutine Call

Syntax: CALL k {,s}

Operands: 0 ≤ k ≤ 1048575

s ∈ [0,1]

Operation: (PC) + 4 → TOS,

k → PC<20:1>;

if s = 1,

(W) → WS,

(STATUS) → STATUSS,

(BSR) → BSRS

Status Affected: None

Encoding:

1st word (k<7:0>)

2nd word(k<19:8>)

1110

1111

110s

k19kkk

k7kkk

kkkk

kkkk0

kkkk8

Description: Subroutine call of entire 2-Mbyte

memory range. First, return address

(PC + 4) is pushed onto the return

stack. If ‘s’ = 1, the W, STATUS and

BSR

registers are also pushed into their

respective shadow registers, WS,

STATUSS and BSRS. If ‘s’ = 0, no

update occurs (default). Then, the

20-bit value ‘k’ is loaded into PC<20:1>.

CALL is a two-cycle instruction.

Words: 2

Cycles: 2

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read literal

‘k’<7:0>,

Push PC to

stack

Read literal

’k’<19:8>,

Write to PC

operation

Example: HERE CALL THERE,1

Before Instruction

PC = address (HERE)

After Instruction

PC = address (THERE)

TOS = address (HERE + 4)

WS = W

BSRS = BSR

STATUSS = STATUS

PIC18F87J50 FAMILY

CLRF Clear f

Syntax: CLRF f {,a}

Operands: 0 ≤ f ≤ 255

a ∈ [0,1]

Operation: 000h → f,

1 → Z

Status Affected: Z

Encoding: 0110 101a ffff ffff

Description: Clears the contents of the specified

If ‘a’ is ‘0’, the Access Bank is selected.

If ‘a’ is ‘1’, the BSR is used to select the

GPR bank (default).

If ‘a’ is ‘0’ and the extended instruction

set is enabled, this instruction operates

in Indexed Literal Offset Addressing

mode whenever f ≤ 95 (5Fh). See

Section 26.2.3 “Byte-Oriented and

Bit-Oriented Instructions in Indexed

Literal Offset Mode” for details.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

Process

Data

Write

Example: CLRF FLAG_REG,1

Before Instruction

FLAG_REG = 5Ah

After Instruction

FLAG_REG = 00h

CLRWDT Clear Watchdog Timer

Syntax: CLRWDT

Operands: None

Operation: 000h → WDT,

000h → WDT postscaler,

1 → TO,

1 → PD

Status Affected: TO, PD

Encoding: 0000 0000 0000 0100

Description: CLRWDT instruction resets the

Watchdog Timer. It also resets the

postscaler of the WDT. Status bits, TO

and PD, are set.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode No

operation

Process

Data

operation

Example: CLRWDT

Before Instruction

WDT Counter = ?

After Instruction

WDT Counter = 00h

WDT Postscaler = 0

TO =1

PD =1

PIC18F87J50 FAMILY

COMF Complement f

Syntax: COMF f {,d {,a}}

Operands: 0 ≤ f ≤ 255

d ∈ [0,1]

a ∈ [0,1]

Operation: f → dest

Status Affected: N, Z

Encoding: 0001 11da ffff ffff

Description: The contents of register ‘f’ are

complemented. If ‘d’ is ‘0’, the result is

stored in W. If ‘d’ is ‘1’, the result is

stored back in register ‘f’ (default).

If ‘a’ is ‘0’, the Access Bank is selected.

If ‘a’ is ‘1’, the BSR is used to select the

GPR bank (default).

If ‘a’ is ‘0’ and the extended instruction

set is enabled, this instruction operates

in Indexed Literal Offset Addressing

mode whenever f ≤ 95 (5Fh). See

Section 26.2.3 “Byte-Oriented and

Bit-Oriented Instructions in Indexed

Literal Offset Mode” for details.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

Process

Data

Write to

destination

Example: COMF REG, 0, 0

Before Instruction

REG = 13h

After Instruction

REG = 13h

W=ECh

CPFSEQ Compare f with W, Skip if f = W

Syntax: CPFSEQ f {,a}

Operands: 0 ≤ f ≤ 255

a ∈ [0,1]

Operation: (f) – (W),

skip if (f) = (W)

(unsigned comparison)

Status Affected: None

Encoding: 0110 001a ffff ffff

Description: Compares the contents of data memory

location ‘f’ to the contents of W by

performing an unsigned subtraction.

If ‘f’ = W, then the fetched instruction is

discarded and a NOP is executed

instead, making this a two-cycle

instruction.

If ‘a’ is ‘0’, the Access Bank is selected.

If ‘a’ is ‘1’, the BSR is used to select the

GPR bank (default).

If ‘a’ is ‘0’ and the extended instruction

set is enabled, this instruction operates

in Indexed Literal Offset Addressing

mode whenever f ≤ 95 (5Fh). See

Section 26.2.3 “Byte-Oriented and

Bit-Oriented Instructions in Indexed

Literal Offset Mode” for details.

Words: 1

Cycles: 1(2)

Note: 3 cycles if skip and followed

by a 2-word instruction.

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

Process

Data

operation

If skip:

Q1 Q2 Q3 Q4

operation

If skip and followed by 2-word instruction:

Q1 Q2 Q3 Q4

operation

Example: HERE CPFSEQ REG, 0

NEQUAL :

EQUAL :

Before Instruction

PC Address = HERE

W=?

REG = ?

After Instruction

If REG = W;

PC = Address (EQUAL)

If REG ≠ W;

PC = Address (NEQUAL)

PIC18F87J50 FAMILY

CPFSGT Compare f with W, Skip if f > W

Syntax: CPFSGT f {,a}

Operands: 0 ≤ f ≤ 255

a ∈ [0,1]

Operation: (f) – (W),

skip if (f) > (W)

(unsigned comparison)

Status Affected: None

Encoding: 0110 010a ffff ffff

Description: Compares the contents of data memory

location ‘f’ to the contents of the W by

performing an unsigned subtraction.

If the contents of ‘f’ are greater than the

contents of WREG, then the fetched

instruction is discarded and a NOP is

executed instead, making this a

two-cycle instruction.

If ‘a’ is ‘0’, the Access Bank is selected.

If ‘a’ is ‘1’, the BSR is used to select the

GPR bank (default).

If ‘a’ is ‘0’ and the extended instruction

set is enabled, this instruction operates

in Indexed Literal Offset Addressing

mode whenever f ≤ 95 (5Fh). See

Section 26.2.3 “Byte-Oriented and

Bit-Oriented Instructions in Indexed

Literal Offset Mode” for details.

Words: 1

Cycles: 1(2)

Note: 3 cycles if skip and followed

by a 2-word instruction.

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

Process

Data

operation

If skip:

Q1 Q2 Q3 Q4

operation

If skip and followed by 2-word instruction:

Q1 Q2 Q3 Q4

operation

Example: HERE CPFSGT REG, 0

NGREATER :

GREATER :

Before Instruction

PC = Address (HERE)

W= ?

After Instruction

If REG > W;

PC = Address (GREATER)

If REG ≤ W;

PC = Address (NGREATER)

CPFSLT Compare f with W, Skip if f < W

Syntax: CPFSLT f {,a}

Operands: 0 ≤ f ≤ 255

a ∈ [0,1]

Operation: (f) – (W),

skip if (f) < (W)

(unsigned comparison)

Status Affected: None

Encoding: 0110 000a ffff ffff

Description: Compares the contents of data memory

location ‘f’ to the contents of W by

performing an unsigned subtraction.

If the contents of ‘f’ are less than the

contents of W, then the fetched

instruction is discarded and a NOP is

executed instead, making this a

two-cycle instruction.

If ‘a’ is ‘0’, the Access Bank is selected.

If ‘a’ is ‘1’, the BSR is used to select the

GPR bank (default).

Words: 1

Cycles: 1(2)

Note: 3 cycles if skip and followed

by a 2-word instruction.

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

Process

Data

operation

If skip:

Q1 Q2 Q3 Q4

operation

If skip and followed by 2-word instruction:

Q1 Q2 Q3 Q4

operation

Example: HERE CPFSLT REG, 1

NLESS :

LESS :

Before Instruction

PC = Address (HERE)

W= ?

After Instruction

If REG < W;

PC = Address (LESS)

If REG ≥ W;

PC = Address (NLESS)

PIC18F87J50 FAMILY

DAW Decimal Adjust W Register

Syntax: DAW

Operands: None

Operation: If [W<3:0> > 9] or [DC = 1] then,

(W<3:0>) + 6 → W<3:0>;

else,

(W<3:0>) → W<3:0>

If [W<7:4> > 9] or [C = 1] then,

(W<7:4>) + 6 → W<7:4>,

C = 1;

else,

(W<7:4>) → W<7:4>

Status Affected: C

Encoding: 0000 0000 0000 0111

Description: DAW adjusts the eight-bit value in W,

resulting from the earlier addition of two

variables (each in packed BCD format)

and produces a correct packed BCD

result.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

Process

Data

Write

Example 1: DAW

Before Instruction

W=A5h

C=0

DC = 0

After Instruction

W = 05h

C=1

DC = 0

Example 2:

Before Instruction

W=CEh

C=0

DC = 0

After Instruction

W = 34h

C=1

DC = 0

DECF Decrement f

Syntax: DECF f {,d {,a}}

Operands: 0 ≤ f ≤ 255

d ∈ [0,1]

a ∈ [0,1]

Operation: (f) – 1 → dest

Status Affected: C, DC, N, OV, Z

Encoding: 0000 01da ffff ffff

Description: Decrement register ‘f’. If ‘d’ is ‘0’, the

result is stored in W. If ‘d’ is ‘1’, the

result is stored back in register ‘f’

(default).

If ‘a’ is ‘0’, the Access Bank is selected.

If ‘a’ is ‘1’, the BSR is used to select the

GPR bank (default).

If ‘a’ is ‘0’ and the extended instruction

set is enabled, this instruction operates

in Indexed Literal Offset Addressing

mode whenever f ≤ 95 (5Fh). See

Section 26.2.3 “Byte-Oriented and

Bit-Oriented Instructions in Indexed

Literal Offset Mode” for details.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

Process

Data

Write to

destination

Example: DECF CNT, 1, 0

Before Instruction

CNT = 01h

Z=0

After Instruction

CNT = 00h

Z=1

PIC18F87J50 FAMILY

DECFSZ Decrement f, Skip if 0

Syntax: DECFSZ f {,d {,a}}

Operands: 0 ≤ f ≤ 255

d ∈ [0,1]

a ∈ [0,1]

Operation: (f) – 1 → dest,

skip if result = 0

Status Affected: None

Encoding: 0010 11da ffff ffff

Description: The contents of register ‘f’ are

decremented. If ‘d’ is ‘0’, the result is

placed in W. If ‘d’ is ‘1’, the result is

placed back in register ‘f’ (default).

If the result is ‘0’, the next instruction

which is already fetched is discarded

and a NOP is executed instead, making

it a two-cycle instruction.

If ‘a’ is ‘0’, the Access Bank is selected.

If ‘a’ is ‘1’, the BSR is used to select the

GPR bank (default).

If ‘a’ is ‘0’ and the extended instruction

set is enabled, this instruction operates

in Indexed Literal Offset Addressing

mode whenever f ≤ 95 (5Fh). See

Section 26.2.3 “Byte-Oriented and

Bit-Oriented Instructions in Indexed

Literal Offset Mode” for details.

Words: 1

Cycles: 1(2)

Note: 3 cycles if skip and followed

by a 2-word instruction.

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

Process

Data

Write to

destination

If skip:

Q1 Q2 Q3 Q4

operation

If skip and followed by 2-word instruction:

Q1 Q2 Q3 Q4

operation

Example: HERE DECFSZ CNT, 1, 1

GOTO LOOP

CONTINUE

Before Instruction

PC = Address (HERE)

After Instruction

CNT = CNT – 1

If CNT = 0;

PC = Address (CONTINUE)

If CNT ≠0;

PC = Address (HERE + 2)

DCFSNZ Decrement f, Skip if not 0

Syntax: DCFSNZ f {,d {,a}}

Operands: 0 ≤ f ≤ 255

d ∈ [0,1]

a ∈ [0,1]

Operation: (f) – 1 → dest,

skip if result ≠ 0

Status Affected: None

Encoding: 0100 11da ffff ffff

Description: The contents of register ‘f’ are

decremented. If ‘d’ is ‘0’, the result is

placed in W. If ‘d’ is ‘1’, the result is

placed back in register ‘f’ (default).

If the result is not ‘0’, the next

instruction which is already fetched is

discarded and a NOP is executed

instead, making it a two-cycle

instruction.

If ‘a’ is ‘0’, the Access Bank is selected.

If ‘a’ is ‘1’, the BSR is used to select the

GPR bank (default).

If ‘a’ is ‘0’ and the extended instruction

set is enabled, this instruction operates

in Indexed Literal Offset Addressing

mode whenever f ≤ 95 (5Fh). See

Section 26.2.3 “Byte-Oriented and

Bit-Oriented Instructions in Indexed

Literal Offset Mode” for details.

Words: 1

Cycles: 1(2)

Note: 3 cycles if skip and followed

by a 2-word instruction.

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

Process

Data

Write to

destination

If skip:

Q1 Q2 Q3 Q4

operation

If skip and followed by 2-word instruction:

Q1 Q2 Q3 Q4

operation

Example: HERE DCFSNZ TEMP, 1, 0

ZERO :

NZERO :

Before Instruction

TEMP = ?

After Instruction

TEMP = TEMP – 1,

If TEMP = 0;

PC = Address (ZERO)

If TEMP ≠0;

PC = Address (NZERO)

PIC18F87J50 FAMILY

GOTO Unconditional Branch

Syntax: GOTO k

Operands: 0 ≤ k ≤ 1048575

Operation: k → PC<20:1>

Status Affected: None

Encoding:

1st word (k<7:0>)

2nd word(k<19:8>)

1110

1111

k19kkk

k7kkk

kkkk

kkkk0

kkkk8

Description: GOTO allows an unconditional branch

anywhere within entire 2-Mbyte memory

range. The 20-bit value ‘k’ is loaded into

PC<20:1>. GOTO is always a two-cycle

instruction.

Words: 2

Cycles: 2

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read literal

‘k’<7:0>,

operation

Read literal

‘k’<19:8>,

Write to PC

operation

Example: GOTO THERE

After Instruction

PC = Address (THERE)

INCF Increment f

Syntax: INCF f {,d {,a}}

Operands: 0 ≤ f ≤ 255

d ∈ [0,1]

a ∈ [0,1]

Operation: (f) + 1 → dest

Status Affected: C, DC, N, OV, Z

Encoding: 0010 10da ffff ffff

Description: The contents of register ‘f’ are

incremented. If ‘d’ is ‘0’, the result is

placed in W. If ‘d’ is ‘1’, the result is

placed back in register ‘f’ (default).

If ‘a’ is ‘0’, the Access Bank is selected.

If ‘a’ is ‘1’, the BSR is used to select the

GPR bank (default).

If ‘a’ is ‘0’ and the extended instruction

set is enabled, this instruction operates

in Indexed Literal Offset Addressing

mode whenever f ≤ 95 (5Fh). See

Section 26.2.3 “Byte-Oriented and

Bit-Oriented Instructions in Indexed

Literal Offset Mode” for details.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

Process

Data

Write to

destination

Example: INCF CNT, 1, 0

Before Instruction

CNT = FFh

Z=0

C=?

DC = ?

After Instruction

CNT = 00h

Z=1

C=1

DC = 1

PIC18F87J50 FAMILY

INCFSZ Increment f, Skip if 0

Syntax: INCFSZ f {,d {,a}}

Operands: 0 ≤ f ≤ 255

d ∈ [0,1]

a ∈ [0,1]

Operation: (f) + 1 → dest,

skip if result = 0

Status Affected: None

Encoding: 0011 11da ffff ffff

Description: The contents of register ‘f’ are

incremented. If ‘d’ is ‘0’, the result is

placed in W. If ‘d’ is ‘1’, the result is

placed back in register ‘f’. (default)

If the result is ‘0’, the next instruction

which is already fetched is discarded

and a NOP is executed instead, making

it a two-cycle instruction.

If ‘a’ is ‘0’, the Access Bank is selected.

If ‘a’ is ‘1’, the BSR is used to select the

GPR bank (default).

If ‘a’ is ‘0’ and the extended instruction

set is enabled, this instruction operates

in Indexed Literal Offset Addressing

mode whenever f ≤ 95 (5Fh). See

Section 26.2.3 “Byte-Oriented and

Bit-Oriented Instructions in Indexed

Literal Offset Mode” for details.

Words: 1

Cycles: 1(2)

Note: 3 cycles if skip and followed

by a 2-word instruction.

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

Process

Data

Write to

destination

If skip:

Q1 Q2 Q3 Q4

operation

If skip and followed by 2-word instruction:

Q1 Q2 Q3 Q4

operation

Example: HERE INCFSZ CNT, 1, 0

NZERO :

ZERO :

Before Instruction

PC = Address (HERE)

After Instruction

CNT = CNT + 1

If CNT = 0;

PC = Address (ZERO)

If CNT ≠0;

PC = Address (NZERO)

INFSNZ Increment f, Skip if not 0

Syntax: INFSNZ f {,d {,a}}

Operands: 0 ≤ f ≤ 255

d ∈ [0,1]

a ∈ [0,1]

Operation: (f) + 1 → dest,

skip if result ≠ 0

Status Affected: None

Encoding: 0100 10da ffff ffff

Description: The contents of register ‘f’ are

incremented. If ‘d’ is ‘0’, the result is

placed in W. If ‘d’ is ‘1’, the result is

placed back in register ‘f’ (default).

If the result is not ‘0’, the next

instruction which is already fetched is

discarded and a NOP is executed

instead, making it a two-cycle

instruction.

If ‘a’ is ‘0’, the Access Bank is selected.

If ‘a’ is ‘1’, the BSR is used to select the

GPR bank (default).

If ‘a’ is ‘0’ and the extended instruction

set is enabled, this instruction operates

in Indexed Literal Offset Addressing

mode whenever f ≤ 95 (5Fh). See

Section 26.2.3 “Byte-Oriented and

Bit-Oriented Instructions in Indexed

Literal Offset Mode” for details.

Words: 1

Cycles: 1(2)

Note: 3 cycles if skip and followed

by a 2-word instruction.

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

Process

Data

Write to

destination

If skip:

Q1 Q2 Q3 Q4

operation

If skip and followed by 2-word instruction:

Q1 Q2 Q3 Q4

operation

Example: HERE INFSNZ REG, 1, 0

ZERO

NZERO

Before Instruction

PC = Address (HERE)

After Instruction

REG = REG + 1

If REG ≠0;

PC = Address (NZERO)

If REG = 0;

PC = Address (ZERO)

PIC18F87J50 FAMILY

IORLW Inclusive OR Literal with W

Syntax: IORLW k

Operands: 0 ≤ k ≤ 255

Operation: (W) .OR. k → W

Status Affected: N, Z

Encoding: 0000 1001 kkkk kkkk

Description: The contents of W are ORed with the

eight-bit literal ‘k’. The result is placed

in W.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

literal ‘k’

Process

Data

Write to

Example: IORLW 35h

Before Instruction

W=9Ah

After Instruction

W=BFh

IORWF Inclusive OR W with f

Syntax: IORWF f {,d {,a}}

Operands: 0 ≤ f ≤ 255

d ∈ [0,1]

a ∈ [0,1]

Operation: (W) .OR. (f) → dest

Status Affected: N, Z

Encoding: 0001 00da ffff ffff

Description: Inclusive OR W with register ‘f’. If ‘d’ is

‘0’, the result is placed in W. If ‘d’ is ‘1’,

the result is placed back in register ‘f’

(default).

If ‘a’ is ‘0’, the Access Bank is selected.

If ‘a’ is ‘1’, the BSR is used to select the

GPR bank (default).

If ‘a’ is ‘0’ and the extended instruction

set is enabled, this instruction operates

in Indexed Literal Offset Addressing

mode whenever f ≤ 95 (5Fh). See

Section 26.2.3 “Byte-Oriented and

Bit-Oriented Instructions in Indexed

Literal Offset Mode” for details.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

Process

Data

Write to

destination

Example: IORWF RESULT, 0, 1

Before Instruction

RESULT = 13h

W = 91h

After Instruction

RESULT = 13h

W = 93h

PIC18F87J50 FAMILY

LFSR Load FSR

Syntax: LFSR f, k

Operands: 0 ≤ f ≤ 2

0 ≤ k ≤ 4095

Operation: k → FSRf

Status Affected: None

Encoding: 1110

1111

1110

0000

00ff

k7kkk

k11kkk

kkkk

Description: The 12-bit literal ‘k’ is loaded into the

file select register pointed to by ‘f’.

Words: 2

Cycles: 2

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read literal

‘k’ MSB

Process

Data

Write

literal ‘k’

MSB to

FSRfH

Decode Read literal

‘k’ LSB

Process

Data

Write literal

‘k’ to FSRfL

Example: LFSR 2, 3ABh

After Instruction

FSR2H = 03h

FSR2L = ABh

MOVF Move f

Syntax: MOVF f {,d {,a}}

Operands: 0 ≤ f ≤ 255

d ∈ [0,1]

a ∈ [0,1]

Operation: f → dest

Status Affected: N, Z

Encoding: 0101 00da ffff ffff

Description: The contents of register ‘f’ are moved to

a destination dependent upon the

status of ‘d’. If ‘d’ is ‘0’, the result is

placed in W. If ‘d’ is ‘1’, the result is

placed back in register ‘f’ (default).

Location ‘f’ can be anywhere in the

256-byte bank.

If ‘a’ is ‘0’, the Access Bank is selected.

If ‘a’ is ‘1’, the BSR is used to select the

GPR bank (default).

If ‘a’ is ‘0’ and the extended instruction

set is enabled, this instruction operates

in Indexed Literal Offset Addressing

mode whenever f ≤ 95 (5Fh). See

Section 26.2.3 “Byte-Oriented and

Bit-Oriented Instructions in Indexed

Literal Offset Mode” for details.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

Process

Data

Write

Example: MOVF REG, 0, 0

Before Instruction

REG = 22h

W=FFh

After Instruction

REG = 22h

W = 22h

PIC18F87J50 FAMILY

MOVFF Move f to f

Syntax: MOVFF fs,fd

Operands: 0 ≤ fs ≤ 4095

0 ≤ fd ≤ 4095

Operation: (fs) → fd

Status Affected: None

Encoding:

1st word (source)

2nd word (destin.)

1100

1111

ffff

ffffs

ffffd

Description: The contents of source register ‘fs’ are

moved to destination register ‘fd’.

Location of source ‘fs’ can be anywhere

in the 4096-byte data space (000h to

FFFh) and location of destination ‘fd’

can also be anywhere from 000h to

FFFh.

Either source or destination can be W

(a useful special situation).

MOVFF is particularly useful for

transferring a data memory location to a

peripheral register (such as the transmit

buffer or an I/O port).

The MOVFF instruction cannot use the

PCL, TOSU, TOSH or TOSL as the

destination register

Words: 2

Cycles: 2

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

(src)

Process

Data

operation

Decode No

operation

No dummy

read

operation

Write

(dest)

Example: MOVFF REG1, REG2

Before Instruction

REG1 = 33h

REG2 = 11h

After Instruction

REG1 = 33h

REG2 = 33h

MOVLB Move Literal to Low Nibble in BSR

Syntax: MOVLW k

Operands: 0 ≤ k ≤ 255

Operation: k → BSR

Status Affected: None

Encoding: 0000 0001 kkkk kkkk

Description: The eight-bit literal ‘k’ is loaded into the

Bank Select Register (BSR). The value

of BSR<7:4> always remains ‘0’

regardless of the value of k7:k4.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

literal ‘k’

Process

Data

Write literal

‘k’ to BSR

Example: MOVLB 5

Before Instruction

BSR Register = 02h

After Instruction

BSR Register = 05h

PIC18F87J50 FAMILY

MOVLW Move Literal to W

Syntax: MOVLW k

Operands: 0 ≤ k ≤ 255

Operation: k → W

Status Affected: None

Encoding: 0000 1110 kkkk kkkk

Description: The eight-bit literal ‘k’ is loaded into W.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

literal ‘k’

Process

Data

Write to

Example: MOVLW 5Ah

After Instruction

W=5Ah

MOVWF Move W to f

Syntax: MOVWF f {,a}

Operands: 0 ≤ f ≤ 255

a ∈ [0,1]

Operation: (W) → f

Status Affected: None

Encoding: 0110 111a ffff ffff

Description: Move data from W to register ‘f’.

Location ‘f’ can be anywhere in the

256-byte bank.

If ‘a’ is ‘0’, the Access Bank is selected.

If ‘a’ is ‘1’, the BSR is used to select the

GPR bank (default).

If ‘a’ is ‘0’ and the extended instruction

set is enabled, this instruction operates

in Indexed Literal Offset Addressing

mode whenever f ≤ 95 (5Fh). See

Section 26.2.3 “Byte-Oriented and

Bit-Oriented Instructions in Indexed

Literal Offset Mode” for details.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

Process

Data

Write

Example: MOVWF REG, 0

Before Instruction

W=4Fh

REG = FFh

After Instruction

W=4Fh

REG = 4Fh

PIC18F87J50 FAMILY

MULLW Multiply Literal with W

Syntax: MULLW k

Operands: 0 ≤ k ≤ 255

Operation: (W) x k → PRODH:PRODL

Status Affected: None

Encoding: 0000 1101 kkkk kkkk

Description: An unsigned multiplication is carried

out between the contents of W and the

8-bit literal ‘k’. The 16-bit result is

placed in PRODH:PRODL register pair.

PRODH contains the high byte.

W is unchanged.

None of the Status flags are affected.

Note that neither Overflow nor Carry is

possible in this operation. A Zero result

is possible but not detected.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

literal ‘k’

Process

Data

Write

registers

PRODH:

PRODL

Example: MULLW 0C4h

Before Instruction

W=E2h

PRODH = ?

PRODL = ?

After Instruction

W=E2h

PRODH = ADh

PRODL = 08h

MULWF Multiply W with f

Syntax: MULWF f {,a}

Operands: 0 ≤ f ≤ 255

a ∈ [0,1]

Operation: (W) x (f) → PRODH:PRODL

Status Affected: None

Encoding: 0000 001a ffff ffff

Description: An unsigned multiplication is carried out

between the contents of W and the

stored in the PRODH:PRODL register

pair. PRODH contains the high byte. Both

W and ‘f’ are unchanged.

None of the Status flags are affected.

Note that neither Overflow nor Carry is

possible in this operation. A Zero result is

possible but not detected.

If ‘a’ is ‘0’, the Access Bank is selected. If

‘a’ is ‘1’, the BSR is used to select the

GPR bank (default).

If ‘a’ is ‘0’ and the extended instruction set

is enabled, this instruction operates in

Indexed Literal Offset Addressing mode

whenever f ≤ 95 (5Fh). See

Section 26.2.3 “Byte-Oriented and

Bit-Oriented Instructions in Indexed

Literal Offset Mode” for details.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

Process

Data

Write

registers

PRODH:

PRODL

Example: MULWF REG, 1

Before Instruction

W=C4h

REG = B5h

PRODH = ?

PRODL = ?

After Instruction

W=C4h

REG = B5h

PRODH = 8Ah

PRODL = 94h

PIC18F87J50 FAMILY

NEGF Negate f

Syntax: NEGF f {,a}

Operands: 0 ≤ f ≤ 255

a ∈ [0,1]

Operation: (f) + 1 → f

Status Affected: N, OV, C, DC, Z

Encoding: 0110 110a ffff ffff

Description: Location ‘f’ is negated using two’s

complement. The result is placed in the

data memory location ‘f’.

If ‘a’ is ‘0’, the Access Bank is selected.

If ‘a’ is ‘1’, the BSR is used to select the

GPR bank (default).

If ‘a’ is ‘0’ and the extended instruction

set is enabled, this instruction operates

in Indexed Literal Offset Addressing

mode whenever f ≤ 95 (5Fh). See

Section 26.2.3 “Byte-Oriented and

Bit-Oriented Instructions in Indexed

Literal Offset Mode” for details.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

Process

Data

Write

Example: NEGF REG, 1

Before Instruction

REG = 0011 1010 [3Ah]

After Instruction

REG = 1100 0110 [C6h]

NOP No Operation

Syntax: NOP

Operands: None

Operation: No operation

Status Affected: None

Encoding: 0000

1111

0000

xxxx

0000

xxxx

0000

xxxx

Description: No operation.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode No

operation

Example:

None.

PIC18F87J50 FAMILY

POP Pop Top of Return Stack

Syntax: POP

Operands: None

Operation: (TOS) → bit bucket

Status Affected: None

Encoding: 0000 0000 0000 0110

Description: The TOS value is pulled off the return

stack and is discarded. The TOS value

then becomes the previous value that

was pushed onto the return stack.

This instruction is provided to enable

the user to properly manage the return

stack to incorporate a software stack.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode No

operation

POP TOS

value

operation

Example: POP

GOTO NEW

Before Instruction

TOS = 0031A2h

Stack (1 level down) = 014332h

After Instruction

TOS = 014332h

PC = NEW

PUSH Push Top of Return Stack

Syntax: PUSH

Operands: None

Operation: (PC + 2) → TOS

Status Affected: None

Encoding: 0000 0000 0000 0101

Description: The PC + 2 is pushed onto the top of

the return stack. The previous TOS

value is pushed down on the stack.

This instruction allows implementing a

software stack by modifying TOS and

then pushing it onto the return stack.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode PUSH

PC + 2 onto

return stack

operation

Example: PUSH

Before Instruction

TOS = 345Ah

PC = 0124h

After Instruction

PC = 0126h

TOS = 0126h

Stack (1 level down) = 345Ah

PIC18F87J50 FAMILY

RCALL Relative Call

Syntax: RCALL n

Operands: -1024 ≤ n ≤ 1023

Operation: (PC) + 2 → TOS,

(PC) + 2 + 2n → PC

Status Affected: None

Encoding: 1101 1nnn nnnn nnnn

Description: Subroutine call with a jump up to 1K

from the current location. First, return

address (PC + 2) is pushed onto the

stack. Then, add the 2’s complement

number ‘2n’ to the PC. Since the PC will

have incremented to fetch the next

instruction, the new address will be

PC + 2 + 2n. This instruction is a

two-cycle instruction.

Words: 1

Cycles: 2

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read literal

‘n’

PUSH PC

to stack

Process

Data

Write to PC

operation

Example: HERE RCALL Jump

Before Instruction

PC = Address (HERE)

After Instruction

PC = Address (Jump)

TOS = Address (HERE + 2)

RESET Reset

Syntax: RESET

Operands: None

Operation: Reset all registers and flags that are

affected by a MCLR Reset.

Status Affected: All

Encoding: 0000 0000 1111 1111

Description: This instruction provides a way to

execute a MCLR Reset in software.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Start

reset

operation

Example: RESET

After Instruction

Registers = Reset Value

Flags* = Reset Value

PIC18F87J50 FAMILY

RETFIE Return from Interrupt

Syntax: RETFIE {s}

Operands: s ∈ [0,1]

Operation: (TOS) → PC,

1 → GIE/GIEH or PEIE/GIEL;

if s = 1,

(WS) → W,

(STATUSS) → STATUS,

(BSRS) → BSR,

PCLATU, PCLATH are unchanged

Status Affected: GIE/GIEH, PEIE/GIEL.

Encoding: 0000 0000 0001 000s

Description: Return from interrupt. Stack is popped

and Top-of-Stack (TOS) is loaded into

the PC. Interrupts are enabled by

setting either the high or low-priority

global interrupt enable bit. If ‘s’ = 1, the

contents of the shadow registers WS,

STATUSS and BSRS are loaded into

their corresponding registers W,

STATUS and BSR. If ‘s’ = 0, no update

of these registers occurs (default).

Words: 1

Cycles: 2

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode No

operation

POP PC

from stack

Set GIEH or

GIEL

operation

Example: RETFIE 1

After Interrupt

PC = TOS

W=WS

BSR = BSRS

STATUS = STATUSS

GIE/GIEH, PEIE/GIEL = 1

RETLW Return Literal to W

Syntax: RETLW k

Operands: 0 ≤ k ≤ 255

Operation: k → W,

(TOS) → PC,

PCLATU, PCLATH are unchanged

Status Affected: None

Encoding: 0000 1100 kkkk kkkk

Description: W is loaded with the eight-bit literal ‘k’.

The program counter is loaded from the

top of the stack (the return address).

The high address latch (PCLATH)

remains unchanged.

Words: 1

Cycles: 2

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

literal ‘k’

Process

Data

POP PC

from stack,

write to W

operation

Example:

CALL TABLE ; W contains table

; offset value

; W now has

; table value

TABLE

ADDWF PCL ; W = offset

RETLW k0 ; Begin table

RETLW k1 ;

RETLW kn ; End of table

Before Instruction

W = 07h

After Instruction

W = value of kn

PIC18F87J50 FAMILY

RETURN Return from Subroutine

Syntax: RETURN {s}

Operands: s ∈ [0,1]

Operation: (TOS) → PC;

if s = 1,

(WS) → W,

(STATUSS) → STATUS,

(BSRS) → BSR,

PCLATU, PCLATH are unchanged

Status Affected: None

Encoding: 0000 0000 0001 001s

Description: Return from subroutine. The stack is

popped and the top of the stack (TOS)

is loaded into the program counter. If

‘s’= 1, the contents of the shadow

registers WS, STATUSS and BSRS are

loaded into their corresponding

registers W, STATUS and BSR. If

‘s’ = 0, no update of these registers

occurs (default).

Words: 1

Cycles: 2

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode No

operation

Process

Data

POP PC

from stack

operation

Example: RETURN

After Instruction:

PC = TOS

RLCF Rotate Left f through Carry

Syntax: RLCF f {,d {,a}}

Operands: 0 ≤ f ≤ 255

d ∈ [0,1]

a ∈ [0,1]

Operation: (f<n>) → dest<n + 1>,

(f<7>) → C,

Status Affected: C, N, Z

Encoding: 0011 01da ffff ffff

Description: The contents of register ‘f’ are rotated

one bit to the left through the Carry flag.

If ‘d’ is ‘0’, the result is placed in W. If ‘d’

is ‘1’, the result is stored back in register

‘f’ (default).

If ‘a’ is ‘0’, the Access Bank is selected.

If ‘a’ is ‘1’, the BSR is used to select the

GPR bank (default).

If ‘a’ is ‘0’ and the extended instruction

set is enabled, this instruction operates

in Indexed Literal Offset Addressing

mode whenever f ≤ 95 (5Fh). See

Section 26.2.3 “Byte-Oriented and

Bit-Oriented Instructions in Indexed

Literal Offset Mode” for details.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

Process

Data

Write to

destination

Example: RLCF REG, 0, 0

Before Instruction

REG = 1110 0110

C=0

After Instruction

REG = 1110 0110

W=1100 1100

C=1

Cregister f

PIC18F87J50 FAMILY

RLNCF Rotate Left f (No Carry)

Syntax: RLNCF f {,d {,a}}

Operands: 0 ≤ f ≤ 255

d ∈ [0,1]

a ∈ [0,1]

Operation: (f<n>) → dest<n + 1>,

(f<7>) → dest<0>

Status Affected: N, Z

Encoding: 0100 01da ffff ffff

Description: The contents of register ‘f’ are rotated

one bit to the left. If ‘d’ is ‘0’, the result

is placed in W. If ‘d’ is ‘1’, the result is

stored back in register ‘f’ (default).

If ‘a’ is ‘0’, the Access Bank is selected.

If ‘a’ is ‘1’, the BSR is used to select the

GPR bank (default).

If ‘a’ is ‘0’ and the extended instruction

set is enabled, this instruction operates

in Indexed Literal Offset Addressing

mode whenever f ≤ 95 (5Fh). See

Section 26.2.3 “Byte-Oriented and

Bit-Oriented Instructions in Indexed

Literal Offset Mode” for details.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

Process

Data

Write to

destination

Example: RLNCF REG, 1, 0

Before Instruction

REG = 1010 1011

After Instruction

REG = 0101 0111

RRCF Rotate Right f through Carry

Syntax: RRCF f {,d {,a}}

Operands: 0 ≤ f ≤ 255

d ∈ [0,1]

a ∈ [0,1]

Operation: (f<n>) → dest<n – 1>,

(f<0>) → C,

Status Affected: C, N, Z

Encoding: 0011 00da ffff ffff

Description: The contents of register ‘f’ are rotated

one bit to the right through the Carry

flag. If ‘d’ is ‘0’, the result is placed in W.

If ‘d’ is ‘1’, the result is placed back in

If ‘a’ is ‘0’, the Access Bank is selected.

If ‘a’ is ‘1’, the BSR is used to select the

GPR bank (default).

If ‘a’ is ‘0’ and the extended instruction

set is enabled, this instruction operates

in Indexed Literal Offset Addressing

mode whenever f ≤ 95 (5Fh). See

Section 26.2.3 “Byte-Oriented and

Bit-Oriented Instructions in Indexed

Literal Offset Mode” for details.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

Process

Data

Write to

destination

Example: RRCF REG, 0, 0

Before Instruction

REG = 1110 0110

C=0

After Instruction

REG = 1110 0110

W=0111 0011

C=0

Cregister f

PIC18F87J50 FAMILY

RRNCF Rotate Right f (No Carry)

Syntax: RRNCF f {,d {,a}}

Operands: 0 ≤ f ≤ 255

d ∈ [0,1]

a ∈ [0,1]

Operation: (f<n>) → dest<n – 1>,

(f<0>) → dest<7>

Status Affected: N, Z

Encoding: 0100 00da ffff ffff

Description: The contents of register ‘f’ are rotated

one bit to the right. If ‘d’ is ‘0’, the result

is placed in W. If ‘d’ is ‘1’, the result is

placed back in register ‘f’ (default).

If ‘a’ is ‘0’, the Access Bank will be

selected, overriding the BSR value. If ‘a’

is ‘1’, then the bank will be selected as

per the BSR value (default).

If ‘a’ is ‘0’ and the extended instruction

set is enabled, this instruction operates

in Indexed Literal Offset Addressing

mode whenever f ≤ 95 (5Fh). See

Section 26.2.3 “Byte-Oriented and

Bit-Oriented Instructions in Indexed

Literal Offset Mode” for details.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

Process

Data

Write to

destination

Example 1: RRNCF REG, 1, 0

Before Instruction

REG = 1101 0111

After Instruction

REG = 1110 1011

Example 2: RRNCF REG, 0, 0

Before Instruction

W=?

REG = 1101 0111

After Instruction

W=1110 1011

REG = 1101 0111

SETF Set f

Syntax: SETF f {,a}

Operands: 0 ≤ f ≤ 255

a ∈ [0,1]

Operation: FFh → f

Status Affected: None

Encoding: 0110 100a ffff ffff

Description: The contents of the specified register

are set to FFh.

If ‘a’ is ‘0’, the Access Bank is selected.

If ‘a’ is ‘1’, the BSR is used to select the

GPR bank (default).

If ‘a’ is ‘0’ and the extended instruction

set is enabled, this instruction operates

in Indexed Literal Offset Addressing

mode whenever f ≤ 95 (5Fh). See

Section 26.2.3 “Byte-Oriented and

Bit-Oriented Instructions in Indexed

Literal Offset Mode” for details.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

Process

Data

Write

Example: SETF REG,1

Before Instruction

REG = 5Ah

After Instruction

REG = FFh

PIC18F87J50 FAMILY

SLEEP Enter Sleep Mode

Syntax: SLEEP

Operands: None

Operation: 00h → WDT,

0 → WDT postscaler,

1 → TO,

0 → PD

Status Affected: TO, PD

Encoding: 0000 0000 0000 0011

Description: The Power-Down status bit (PD) is

cleared. The Time-out status bit (TO)

is set. The Watchdog Timer and its

postscaler are cleared.

The processor is put into Sleep mode

with the oscillator stopped.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode No

operation

Process

Data

Go to

Sleep

Example: SLEEP

Before Instruction

TO =?

PD =?

After Instruction

TO =1 †

PD =0

† If WDT causes wake-up, this bit is cleared.

SUBFWB Subtract f from W with Borrow

Syntax: SUBFWB f {,d {,a}}

Operands: 0 ≤ f ≤ 255

d ∈ [0,1]

a ∈ [0,1]

Operation: (W) – (f) – (C) → dest

Status Affected: N, OV, C, DC, Z

Encoding: 0101 01da ffff ffff

Description: Subtract register ‘f’ and Carry flag

(borrow) from W (2’s complement

method). If ‘d’ is ‘0’, the result is stored in

W. If ‘d’ is ‘1’, the result is stored in

If ‘a’ is ‘0’, the Access Bank is selected. If

‘a’ is ‘1’, the BSR is used to select the

GPR bank (default).

If ‘a’ is ‘0’ and the extended instruction

set is enabled, this instruction operates in

Indexed Literal Offset Addressing mode

whenever f ≤ 95 (5Fh). See

Section 26.2.3 “Byte-Oriented and

Bit-Oriented Instructions in Indexed

Literal Offset Mode” for details.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

Process

Data

Write to

destination

Example 1: SUBFWB REG, 1, 0

Before Instruction

REG = 3

W=2

C=1

After Instruction

REG = FF

W=2

C=0

Z=0

N = 1 ; result is negative

Example 2: SUBFWB REG, 0, 0

Before Instruction

REG = 2

W=5

C=1

After Instruction

REG = 2

W=3

C=1

Z=0

N = 0 ; result is positive

Example 3: SUBFWB REG, 1, 0

Before Instruction

REG = 1

W=2

C=0

After Instruction

REG = 0

W=2

C=1

Z = 1 ; result is zero

N=0

PIC18F87J50 FAMILY

SUBLW Subtract W from Literal

Syntax: SUBLW k

Operands: 0 ≤ k ≤ 255

Operation: k – (W) → W

Status Affected: N, OV, C, DC, Z

Encoding: 0000 1000 kkkk kkkk

Description: W is subtracted from the eight-bit

literal ‘k’. The result is placed in W.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

literal ‘k’

Process

Data

Write to

Example 1: SUBLW 02h

Before Instruction

W = 01h

C=?

After Instruction

W = 01h

C = 1 ; result is positive

Z=0

N=0

Example 2: SUBLW 02h

Before Instruction

W = 02h

C=?

After Instruction

W = 00h

C = 1 ; result is zero

Z=1

N=0

Example 3: SUBLW 02h

Before Instruction

W = 03h

C=?

After Instruction

W = FFh ; (2’s complement)

C = 0 ; result is negative

Z=0

N=1

SUBWF Subtract W from f

Syntax: SUBWF f {,d {,a}}

Operands: 0 ≤ f ≤ 255

d ∈ [0,1]

a ∈ [0,1]

Operation: (f) – (W) → dest

Status Affected: N, OV, C, DC, Z

Encoding: 0101 11da ffff ffff

Description: Subtract W from register ‘f’ (2’s

complement method). If ‘d’ is ‘0’, the

result is stored in W. If ‘d’ is ‘1’, the result

is stored back in register ‘f’ (default).

If ‘a’ is ‘0’, the Access Bank is selected.

If ‘a’ is ‘1’, the BSR is used to select the

GPR bank (default).

If ‘a’ is ‘0’ and the extended instruction

set is enabled, this instruction operates

in Indexed Literal Offset Addressing

mode whenever f ≤ 95 (5Fh). See

Section 26.2.3 “Byte-Oriented and

Bit-Oriented Instructions in Indexed

Literal Offset Mode” for details.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

Process

Data

Write to

destination

Example 1: SUBWF REG, 1, 0

Before Instruction

REG = 3

W=2

C=?

After Instruction

REG = 1

W=2

C = 1 ; result is positive

Z=0

N=0

Example 2: SUBWF REG, 0, 0

Before Instruction

REG = 2

W=2

C=?

After Instruction

REG = 2

W=0

C = 1 ; result is zero

Z=1

N=0

Example 3: SUBWF REG, 1, 0

Before Instruction

REG = 1

W=2

C=?

After Instruction

REG = FFh ;(2’s complement)

W=2

C = 0 ; result is negative

Z=0

N=1

PIC18F87J50 FAMILY

SUBWFB Subtract W from f with Borrow

Syntax: SUBWFB f {,d {,a}}

Operands: 0 ≤ f ≤ 255

d ∈ [0,1]

a ∈ [0,1]

Operation: (f) – (W) – (C) → dest

Status Affected: N, OV, C, DC, Z

Encoding: 0101 10da ffff ffff

Description: Subtract W and the Carry flag (borrow)

from register ‘f’ (2’s complement

method). If ‘d’ is ‘0’, the result is stored

in W. If ‘d’ is ‘1’, the result is stored back

in register ‘f’ (default).

If ‘a’ is ‘0’, the Access Bank is selected.

If ‘a’ is ‘1’, the BSR is used to select the

GPR bank (default).

If ‘a’ is ‘0’ and the extended instruction

set is enabled, this instruction operates

in Indexed Literal Offset Addressing

mode whenever f ≤ 95 (5Fh). See

Section 26.2.3 “Byte-Oriented and

Bit-Oriented Instructions in Indexed

Literal Offset Mode” for details.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

Process

Data

Write to

destination

Example 1: SUBWFB REG, 1, 0

Before Instruction

REG = 19h (0001 1001)

W=0Dh (0000 1101)

C=1

After Instruction

REG = 0Ch (0000 1011)

W=0Dh (0000 1101)

C=1

Z=0

N = 0 ; result is positive

Example 2: SUBWFB REG, 0, 0

Before Instruction

REG = 1Bh (0001 1011)

W=1Ah (0001 1010)

C=0

After Instruction

REG = 1Bh (0001 1011)

W = 00h

C=1

Z = 1 ; result is zero

N=0

Example 3: SUBWFB REG, 1, 0

Before Instruction

REG = 03h (0000 0011)

W=0Eh (0000 1101)

C=1

After Instruction

REG = F5h (1111 0100)

; [2’s comp]

W=0Eh (0000 1101)

C=0

Z=0

N = 1 ; result is negative

SWAPF Swap f

Syntax: SWAPF f {,d {,a}}

Operands: 0 ≤ f ≤ 255

d ∈ [0,1]

a ∈ [0,1]

Operation: (f<3:0>) → dest<7:4>,

(f<7:4>) → dest<3:0>

Status Affected: None

Encoding: 0011 10da ffff ffff

Description: The upper and lower nibbles of register

‘f’ are exchanged. If ‘d’ is ‘0’, the result

is placed in W. If ‘d’ is ‘1’, the result is

placed in register ‘f’ (default).

If ‘a’ is ‘0’, the Access Bank is selected.

If ‘a’ is ‘1’, the BSR is used to select the

GPR bank (default).

If ‘a’ is ‘0’ and the extended instruction

set is enabled, this instruction operates

in Indexed Literal Offset Addressing

mode whenever f ≤ 95 (5Fh). See

Section 26.2.3 “Byte-Oriented and

Bit-Oriented Instructions in Indexed

Literal Offset Mode” for details.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

Process

Data

Write to

destination

Example: SWAPF REG, 1, 0

Before Instruction

REG = 53h

After Instruction

REG = 35h

PIC18F87J50 FAMILY

TBLRD Table Read

Syntax: TBLRD ( *; *+; *-; +*)

Operands: None

Operation: if TBLRD *,

(Prog Mem (TBLPTR)) → TABLAT,

TBLPTR – No Change;

if TBLRD *+,

(Prog Mem (TBLPTR)) → TABLAT,

(TBLPTR) + 1 → TBLPTR;

if TBLRD *-,

(Prog Mem (TBLPTR)) → TABLAT,

(TBLPTR) – 1 → TBLPTR;

if TBLRD +*,

(TBLPTR) + 1 → TBLPTR,

(Prog Mem (TBLPTR)) → TABLAT

Status Affected: None

Encoding: 0000 0000 0000 10nn

nn=0 *

=1 *+

=2 *-

=3 +*

Description: This instruction is used to read the contents

of Program Memory (P.M.). To address the

program memory, a pointer called Table

Pointer (TBLPTR) is used.

The TBLPTR (a 21-bit pointer) points to

each byte in the program memory. TBLPTR

has a 2-Mbyte address range.

TBLPTR<0> = 0: Least Significant Byte of

Program Memory Word

TBLPTR<0> = 1: Most Significant Byte of

Program Memory Word

The TBLRD instruction can modify the value

of TBLPTR as follows:

• no change

• post-increment

• post-decrement

• pre-increment

Words: 1

Cycles: 2

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode No

operation

No operation

(Read Program

Memory)

operation

No operation

(Write

TABLAT)

TBLRD Table Read (Continued)

Example 1: TBLRD *+ ;

Before Instruction

TABLAT = 55h

TBLPTR = 00A356h

MEMORY(00A356h) = 34h

After Instruction

TABLAT = 34h

TBLPTR = 00A357h

Example 2: TBLRD +* ;

Before Instruction

TABLAT = AAh

TBLPTR = 01A357h

MEMORY(01A357h) = 12h

MEMORY(01A358h) = 34h

After Instruction

TABLAT = 34h

TBLPTR = 01A358h

PIC18F87J50 FAMILY

TBLWT Table Write

Syntax: TBLWT ( *; *+; *-; +*)

Operands: None

Operation: if TBLWT*,

(TABLAT) → Holding Register,

TBLPTR – No Change;

if TBLWT*+,

(TABLAT) → Holding Register,

(TBLPTR) + 1 → TBLPTR;

if TBLWT*-,

(TABLAT) → Holding Register,

(TBLPTR) – 1 → TBLPTR;

if TBLWT+*,

(TBLPTR) + 1 → TBLPTR,

(TABLAT) → Holding Register

Status Affected: None

Encoding: 0000 0000 0000 11nn

nn=0 *

=1 *+

=2 *-

=3 +*

Description: This instruction uses the 3 LSBs of

TBLPTR to determine which of the

8 holding registers the TABLAT is written

to. The holding registers are used to

program the contents of Program Memory

(P.M.). (Refer to Section 5.0 “Memory

Organization” for additional details on

programming Flash memory.)

The TBLPTR (a 21-bit pointer) points to

each byte in the program memory.

TBLPTR has a 2-Mbyte address range.

The LSb of the TBLPTR selects which

byte of the program memory location to

access.

TBLPTR<0> = 0: Least Significant Byte

of Program Memory

Word

TBLPTR<0> = 1: Most Significant Byte

of Program Memory

Word

The TBLWT instruction can modify the

value of TBLPTR as follows:

• no change

• post-increment

• post-decrement

• pre-increment

Words: 1

Cycles: 2

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode No

operation

(Read

TABLAT)

operation

(Write to

Holding

TBLWT Table Write (Continued)

Example 1: TBLWT *+;

Before Instruction

TABLAT = 55h

TBLPTR = 00A356h

HOLDING REGISTER

(00A356h) = FFh

After Instructions (table write completion)

TABLAT = 55h

TBLPTR = 00A357h

HOLDING REGISTER

(00A356h) = 55h

Example 2: TBLWT +*;

Before Instruction

TABLAT = 34h

TBLPTR = 01389Ah

HOLDING REGISTER

(01389Ah) = FFh

HOLDING REGISTER

(01389Bh) = FFh

After Instruction (table write completion)

TABLAT = 34h

TBLPTR = 01389Bh

HOLDING REGISTER

(01389Ah) = FFh

HOLDING REGISTER

(01389Bh) = 34h

PIC18F87J50 FAMILY

TSTFSZ Test f, Skip if 0

Syntax: TSTFSZ f {,a}

Operands: 0 ≤ f ≤ 255

a ∈ [0,1]

Operation: skip if f = 0

Status Affected: None

Encoding: 0110 011a ffff ffff

Description: If ‘f’ = 0, the next instruction fetched

during the current instruction execution

is discarded and a NOP is executed,

making this a two-cycle instruction.

If ‘a’ is ‘0’, the Access Bank is selected.

If ‘a’ is ‘1’, the BSR is used to select the

GPR bank (default).

If ‘a’ is ‘0’ and the extended instruction

set is enabled, this instruction operates

in Indexed Literal Offset Addressing

mode whenever f ≤ 95 (5Fh). See

Section 26.2.3 “Byte-Oriented and

Bit-Oriented Instructions in Indexed

Literal Offset Mode” for details.

Words: 1

Cycles: 1(2)

Note: 3 cycles if skip and followed

by a 2-word instruction.

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

Process

Data

operation

If skip:

Q1 Q2 Q3 Q4

operation

If skip and followed by 2-word instruction:

Q1 Q2 Q3 Q4

operation

Example: HERE TSTFSZ CNT, 1

NZERO :

ZERO :

Before Instruction

PC = Address (HERE)

After Instruction

If CNT = 00h,

PC = Address (ZERO)

If CNT ≠00h,

PC = Address (NZERO)

XORLW Exclusive OR Literal with W

Syntax: XORLW k

Operands: 0 ≤ k ≤ 255

Operation: (W) .XOR. k → W

Status Affected: N, Z

Encoding: 0000 1010 kkkk kkkk

Description: The contents of W are XORed with

the 8-bit literal ‘k’. The result is placed

in W.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

literal ‘k’

Process

Data

Write to

Example: XORLW 0AFh

Before Instruction

W=B5h

After Instruction

W=1Ah

PIC18F87J50 FAMILY

XORWF Exclusive OR W with f

Syntax: XORWF f {,d {,a}}

Operands: 0 ≤ f ≤ 255

d ∈ [0,1]

a ∈ [0,1]

Operation: (W) .XOR. (f) → dest

Status Affected: N, Z

Encoding: 0001 10da ffff ffff

Description: Exclusive OR the contents of W with

in W. If ‘d’ is ‘1’, the result is stored back

in the register ‘f’ (default).

If ‘a’ is ‘0’, the Access Bank is selected.

If ‘a’ is ‘1’, the BSR is used to select the

GPR bank (default).

If ‘a’ is ‘0’ and the extended instruction

set is enabled, this instruction operates

in Indexed Literal Offset Addressing

mode whenever f ≤ 95 (5Fh). See

Section 26.2.3 “Byte-Oriented and

Bit-Oriented Instructions in Indexed

Literal Offset Mode” for details.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

Process

Data

Write to

destination

Example: XORWF REG, 1, 0

Before Instruction

REG = AFh

W=B5h

After Instruction

REG = 1Ah

W=B5h

PIC18F87J50 FAMILY

26.2 Extended Instruction Set

In addition to the standard 75 instructions of the PIC18

instruction set, the PIC18F87J50 family of devices also

provide an optional extension to the core CPU function-

ality. The added features include eight additional

instructions that augment Indirect and Indexed

Addressing operations and the implementation of

Indexed Literal Offset Addressing for many of the

standard PIC18 instructions.

The additional features of the extended instruction set

are enabled by default on unprogrammed devices.

Users must properly set or clear the XINST Configura-

tion bit during programming to enable or disable these

features.

The instructions in the extended set can all be

classified as literal operations, which either manipulate

the File Select Registers, or use them for Indexed

Addressing. Two of the instructions, ADDFSR and

SUBFSR, each have an additional special instantiation

for using FSR2. These versions (ADDULNK and

SUBULNK) allow for automatic return after execution.

The extended instructions are specifically implemented

to optimize re-entrant program code (that is, code that

is recursive or that uses a software stack) written in

high-level languages, particularly C. Among other

things, they allow users working in high-level

languages to perform certain operations on data

structures more efficiently. These include:

• dynamic allocation and deallocation of software

stack space when entering and leaving

subroutines

• Function Pointer invocation

• Software Stack Pointer manipulation

• manipulation of variables located in a software

stack

A summary of the instructions in the extended instruc-

tion set is provided in Table 26-3. Detailed descriptions

are provided in Section 26.2.2 “Extended Instruction

Set”. The opcode field descriptions in Table 26-1 (page

366) apply to both the standard and extended PIC18

instruction sets.

26.2.1 EXTENDED INSTRUCTION SYNTAX

Most of the extended instructions use indexed argu-

ments, using one of the File Select Registers and some

offset to specify a source or destination register. When

an argument for an instruction serves as part of

Indexed Addressing, it is enclosed in square brackets

(“[ ]”). This is done to indicate that the argument is used

as an index or offset. The MPASM™ Assembler will

flag an error if it determines that an index or offset value

is not bracketed.

When the extended instruction set is enabled, brackets

are also used to indicate index arguments in

byte-oriented and bit-oriented instructions. This is in

addition to other changes in their syntax. For more

details, see Section 26.2.3.1 “Extended Instruction

Syntax with Standard PIC18 Commands”.

TABLE 26-3: EXTENSIONS TO THE PIC18 INSTRUCTION SET

Note: The instruction set extension and the

Indexed Literal Offset Addressing mode

were designed for optimizing applications

written in C; the user may likely never use

these instructions directly in assembler.

The syntax for these commands is

provided as a reference for users who may

be reviewing code that has been

generated by a compiler.

Note: In the past, square brackets have been

used to denote optional arguments in the

PIC18 and earlier instruction sets. In this

text and going forward, optional

arguments are denoted by braces (“{ }”).

Mnemonic,

Operands Description Cycles

16-Bit Instruction Word Status

Affected

MSb LSb

ADDFSR

ADDULNK

CALLW

MOVSF

MOVSS

PUSHL

SUBFSR

SUBULNK

f, k

zs, fd

zs, zd

f, k

Add Literal to FSR

Add Literal to FSR2 and Return

Call Subroutine using WREG

Move zs (source) to 1st word

fd (destination) 2nd word

Move zs (source) to 1st word

zd (destination) 2nd word

Store Literal at FSR2,

Decrement FSR2

Subtract Literal from FSR

Subtract Literal from FSR2 and

Return

1110

0000

1110

1111

1110

1111

1110

1000

0000

1011

ffff

1011

xxxx

1010

1001

ffkk

11kk

0001

0zzz

ffff

1zzz

xzzz

kkkk

ffkk

11kk

kkkk

0100

zzzz

ffff

zzzz

kkkk

None

PIC18F87J50 FAMILY

26.2.2 EXTENDED INSTRUCTION SET

ADDFSR Add Literal to FSR

Syntax: ADDFSR f, k

Operands: 0 ≤ k ≤ 63

f ∈ [ 0, 1, 2 ]

Operation: FSR(f) + k → FSR(f)

Status Affected: None

Encoding: 1110 1000 ffkk kkkk

Description: The 6-bit literal ‘k’ is added to the

contents of the FSR specified by ‘f’.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

literal ‘k’

Process

Data

Write to

FSR

Example: ADDFSR 2, 23h

Before Instruction

FSR2 = 03FFh

After Instruction

FSR2 = 0422h

ADDULNK Add Literal to FSR2 and Return

Syntax: ADDULNK k

Operands: 0 ≤ k ≤ 63

Operation: FSR2 + k → FSR2,

(TOS) → PC

Status Affected: None

Encoding: 1110 1000 11kk kkkk

Description: The 6-bit literal ‘k’ is added to the

contents of FSR2. A RETURN is then

executed by loading the PC with the

TOS.

The instruction takes two cycles to

execute; a NOP is performed during

the second cycle.

This may be thought of as a special

case of the ADDFSR instruction,

where f = 3 (binary ‘11’); it operates

only on FSR2.

Words: 1

Cycles: 2

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

literal ‘k’

Process

Data

Write to

FSR

Operation

Example: ADDULNK 23h

Before Instruction

FSR2 = 03FFh

PC = 0100h

After Instruction

FSR2 = 0422h

PC = (TOS)

Note: All PIC18 instructions may take an optional label argument preceding the instruction mnemonic for use in

symbolic addressing. If a label is used, the instruction format then becomes: {label} instruction argument(s).

PIC18F87J50 FAMILY

CALLW Subroutine Call using WREG

Syntax: CALLW

Operands: None

Operation: (PC + 2) → TOS,

(W) → PCL,

(PCLATH) → PCH,

(PCLATU) → PCU

Status Affected: None

Encoding: 0000 0000 0001 0100

Description First, the return address (PC + 2) is

pushed onto the return stack. Next, the

contents of W are written to PCL; the

existing value is discarded. Then, the

contents of PCLATH and PCLATU are

latched into PCH and PCU,

respectively. The second cycle is

executed as a NOP instruction while the

new next instruction is fetched.

Unlike CALL, there is no option to

update W, STATUS or BSR.

Words: 1

Cycles: 2

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

WREG

Push PC to

stack

operation

Example: HERE CALLW

Before Instruction

PC = address (HERE)

PCLATH = 10h

PCLATU = 00h

W = 06h

After Instruction

PC = 001006h

TOS = address (HERE + 2)

PCLATH = 10h

PCLATU = 00h

W = 06h

MOVSF Move Indexed to f

Syntax: MOVSF [zs], fd

Operands: 0 ≤ zs ≤ 127

0 ≤ fd ≤ 4095

Operation: ((FSR2) + zs) → fd

Status Affected: None

Encoding:

1st word (source)

2nd word (destin.)

1110

1111

1011

ffff

0zzz

ffff

zzzzs

ffffd

Description: The contents of the source register are

moved to destination register ‘fd’. The

actual address of the source register is

determined by adding the 7-bit literal

offset ‘zs’, in the first word, to the value

of FSR2. The address of the destination

‘fd’ in the second word. Both addresses

can be anywhere in the 4096-byte data

space (000h to FFFh).

The MOVSF instruction cannot use the

PCL, TOSU, TOSH or TOSL as the

destination register.

If the resultant source address points to

an Indirect Addressing register, the

value returned will be 00h.

Words: 2

Cycles: 2

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Determine

source addr

Determine

source addr

Read

source reg

Decode No

operation

No dummy

read

operation

Write

(dest)

Example: MOVSF [05h], REG2

Before Instruction

FSR2 = 80h

Contents

of 85h = 33h

REG2 = 11h

After Instruction

FSR2 = 80h

Contents

of 85h = 33h

REG2 = 33h

PIC18F87J50 FAMILY

MOVSS Move Indexed to Indexed

Syntax: MOVSS [zs], [zd]

Operands: 0 ≤ zs ≤ 127

0 ≤ zd ≤ 127

Operation: ((FSR2) + zs) → ((FSR2) + zd)

Status Affected: None

Encoding:

1st word (source)

2nd word (dest.)

1110

1111

1011

xxxx

1zzz

xzzz

zzzzs

zzzzd

Description The contents of the source register are

moved to the destination register. The

addresses of the source and destination

registers are determined by adding the

7-bit literal offsets ‘zs’ or ‘zd’,

respectively, to the value of FSR2. Both

registers can be located anywhere in

the 4096-byte data memory space

(000h to FFFh).

The MOVSS instruction cannot use the

PCL, TOSU, TOSH or TOSL as the

destination register.

If the resultant source address points to

an Indirect Addressing register, the

value returned will be 00h. If the

resultant destination address points to

an Indirect Addressing register, the

instruction will execute as a NOP.

Words: 2

Cycles: 2

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Determine

source addr

Determine

source addr

Read

source reg

Decode Determine

dest addr

Determine

dest addr

Write

to dest reg

Example: MOVSS [05h], [06h]

Before Instruction

FSR2 = 80h

Contents

of 85h = 33h

Contents

of 86h = 11h

After Instruction

FSR2 = 80h

Contents

of 85h = 33h

Contents

of 86h = 33h

PUSHL Store Literal at FSR2, Decrement FSR2

Syntax: PUSHL k

Operands: 0 ≤ k ≤ 255

Operation: k → (FSR2),

FSR2 – 1 → FSR2

Status Affected: None

Encoding: 1111 1010 kkkk kkkk

Description: The 8-bit literal ‘k’ is written to the data

memory address specified by FSR2.

FSR2 is decremented by 1 after the

operation.

This instruction allows users to push

values onto a software stack.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read ‘k’ Process

data

Write to

destination

Example: PUSHL 08h

Before Instruction

FSR2H:FSR2L = 01ECh

Memory (01ECh) = 00h

After Instruction

FSR2H:FSR2L = 01EBh

Memory (01ECh) = 08h

PIC18F87J50 FAMILY

SUBFSR Subtract Literal from FSR

Syntax: SUBFSR f, k

Operands: 0 ≤ k ≤ 63

f ∈ [ 0, 1, 2 ]

Operation: FSRf – k → FSRf

Status Affected: None

Encoding: 1110 1001 ffkk kkkk

Description: The 6-bit literal ‘k’ is subtracted from

the contents of the FSR specified

by ‘f’.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

Process

Data

Write to

destination

Example: SUBFSR 2, 23h

Before Instruction

FSR2 = 03FFh

After Instruction

FSR2 = 03DCh

SUBULNK Subtract Literal from FSR2 and Return

Syntax: SUBULNK k

Operands: 0 ≤ k ≤ 63

Operation: FSR2 – k → FSR2,

(TOS) → PC

Status Affected: None

Encoding: 1110 1001 11kk kkkk

Description: The 6-bit literal ‘k’ is subtracted from the

contents of the FSR2. A RETURN is then

executed by loading the PC with the

TOS.

The instruction takes two cycles to

execute; a NOP is performed during the

second cycle.

This may be thought of as a special case

of the SUBFSR instruction, where f = 3

(binary ‘11’); it operates only on FSR2.

Words: 1

Cycles: 2

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

Process

Data

Write to

destination

Operation

Example: SUBULNK 23h

Before Instruction

FSR2 = 03FFh

PC = 0100h

After Instruction

FSR2 = 03DCh

PC = (TOS)

PIC18F87J50 FAMILY

26.2.3 BYTE-ORIENTED AND

BIT-ORIENTED INSTRUCTIONS IN

INDEXED LITERAL OFFSET MODE

In addition to eight new commands in the extended set,

enabling the extended instruction set also enables

Indexed Literal Offset Addressing (Section 5.6.1

“Indexed Addressing with Literal Offset”). This has

a significant impact on the way that many commands of

the standard PIC18 instruction set are interpreted.

When the extended set is disabled, addresses embed-

ded in opcodes are treated as literal memory locations:

either as a location in the Access Bank (a = 0) or in a

GPR bank designated by the BSR (a = 1). When the

extended instruction set is enabled and a = 0, however,

a file register argument of 5Fh or less is interpreted as

an offset from the pointer value in FSR2 and not as a

literal address. For practical purposes, this means that

all instructions that use the Access RAM bit as an

argument – that is, all byte-oriented and bit-oriented

instructions, or almost half of the core PIC18 instruc-

tions – may behave differently when the extended

instruction set is enabled.

When the content of FSR2 is 00h, the boundaries of the

Access RAM are essentially remapped to their original

values. This may be useful in creating

backward-compatible code. If this technique is used, it

may be necessary to save the value of FSR2 and

restore it when moving back and forth between C and

assembly routines in order to preserve the Stack

Pointer. Users must also keep in mind the syntax

requirements of the extended instruction set (see

Section 26.2.3.1 “Extended Instruction Syntax with

Standard PIC18 Commands”).

Although the Indexed Literal Offset mode can be very

useful for dynamic stack and pointer manipulation, it

can also be very annoying if a simple arithmetic opera-

tion is carried out on the wrong register. Users who are

accustomed to the PIC18 programming must keep in

mind that, when the extended instruction set is

enabled, register addresses of 5Fh or less are used for

Indexed Literal Offset Addressing.

Representative examples of typical byte-oriented and

bit-oriented instructions in the Indexed Literal Offset

mode are provided on the following page to show how

execution is affected. The operand conditions shown in

the examples are applicable to all instructions of these

types.

26.2.3.1 Extended Instruction Syntax with

Standard PIC18 Commands

When the extended instruction set is enabled, the file

bit-oriented commands is replaced with the literal offset

value ‘k’. As already noted, this occurs only when ‘f’ is

less than or equal to 5Fh. When an offset value is used,

it must be indicated by square brackets (“[ ]”). As with

the extended instructions, the use of brackets indicates

to the compiler that the value is to be interpreted as an

index or an offset. Omitting the brackets, or using a

value greater than 5Fh within the brackets, will

generate an error in the MPASM Assembler.

If the index argument is properly bracketed for Indexed

Literal Offset Addressing, the Access RAM argument is

never specified; it will automatically be assumed to be

‘0’. This is in contrast to standard operation (extended

instruction set disabled), when ‘a’ is set on the basis of

the target address. Declaring the Access RAM bit in

this mode will also generate an error in the MPASM

Assembler.

The destination argument ‘d’ functions as before.

In the latest versions of the MPASM Assembler,

language support for the extended instruction set must

be explicitly invoked. This is done with either the

command line option, /y, or the PE directive in the

source listing.

26.2.4 CONSIDERATIONS WHEN

ENABLING THE EXTENDED

INSTRUCTION SET

It is important to note that the extensions to the instruc-

tion set may not be beneficial to all users. In particular,

users who are not writing code that uses a software

stack may not benefit from using the extensions to the

instruction set.

Additionally, the Indexed Literal Offset Addressing

mode may create issues with legacy applications

written to the PIC18 assembler. This is because

instructions in the legacy code may attempt to address

registers in the Access Bank below 5Fh. Since these

addresses are interpreted as literal offsets to FSR2

when the instruction set extension is enabled, the

application may read or write to the wrong data

addresses.

When porting an application to the PIC18F87J10 fam-

ily, it is very important to consider the type of code. A

large, re-entrant application that is written in C and

would benefit from efficient compilation will do well

when using the instruction set extensions. Legacy

applications that heavily use the Access Bank will most

likely not benefit from using the extended instruction

set.

Note: Enabling the PIC18 instruction set exten-

sion may cause legacy applications to

behave erratically or fail entirely.

PIC18F87J50 FAMILY

ADDWF ADD W to Indexed

(Indexed Literal Offset mode)

Syntax: ADDWF [k] {,d}

Operands: 0 ≤ k ≤ 95

d ∈ [0,1]

Operation: (W) + ((FSR2) + k) → dest

Status Affected: N, OV, C, DC, Z

Encoding: 0010 01d0 kkkk kkkk

Description: The contents of W are added to the

contents of the register indicated by

FSR2, offset by the value ‘k’.

If ‘d’ is ‘0’, the result is stored in W. If ‘d’

is ‘1’, the result is stored back in

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read ‘k’ Process

Data

Write to

destination

Example: ADDWF [OFST] ,0

Before Instruction

W = 17h

OFST = 2Ch

FSR2 = 0A00h

Contents

of 0A2Ch = 20h

After Instruction

W = 37h

Contents

of 0A2Ch = 20h

BSF Bit Set Indexed

(Indexed Literal Offset mode)

Syntax: BSF [k], b

Operands: 0 ≤ f ≤ 95

0 ≤ b ≤ 7

Operation: 1 → ((FSR2) + k)

Status Affected: None

Encoding: 1000 bbb0 kkkk kkkk

Description: Bit ‘b’ of the register indicated by FSR2,

offset by the value ‘k’, is set.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read

Process

Data

Write to

destination

Example: BSF [FLAG_OFST], 7

Before Instruction

FLAG_OFST = 0Ah

FSR2 = 0A00h

Contents

of 0A0Ah = 55h

After Instruction

Contents

of 0A0Ah = D5h

SETF Set Indexed

(Indexed Literal Offset mode)

Syntax: SETF [k]

Operands: 0 ≤ k ≤ 95

Operation: FFh → ((FSR2) + k)

Status Affected: None

Encoding: 0110 1000 kkkk kkkk

Description: The contents of the register indicated by

FSR2, offset by ‘k’, are set to FFh.

Words: 1

Cycles: 1

Q Cycle Activity:

Q1 Q2 Q3 Q4

Decode Read ‘k’ Process

Data

Write

Example: SETF [OFST]

Before Instruction

OFST = 2Ch

FSR2 = 0A00h

Contents

of 0A2Ch = 00h

After Instruction

Contents

of 0A2Ch = FFh

PIC18F87J50 FAMILY

26.2.5 SPECIAL CONSIDERATIONS WITH

MICROCHIP MPLAB® IDE TOOLS

The latest versions of Microchip’s software tools have

been designed to fully support the extended instruction

set for the PIC18F87J10 family. This includes the

MPLAB C18 C Compiler, MPASM assembly language

and MPLAB Integrated Development Environment

(IDE).

When selecting a target device for software

development, MPLAB IDE will automatically set default

Configuration bits for that device. The default setting for

the XINST Configuration bit is ‘0’, disabling the

extended instruction set and Indexed Literal Offset

Addressing. For proper execution of applications

developed to take advantage of the extended

instruction set, XINST must be set during

programming.

To develop software for the extended instruction set,

the user must enable support for the instructions and

the Indexed Addressing mode in their language tool(s).

Depending on the environment being used, this may be

done in several ways:

• A menu option or dialog box within the

environment that allows the user to configure the

language tool and its settings for the project

• A command line option

• A directive in the source code

These options vary between different compilers,

assemblers and development environments. Users are

encouraged to review the documentation accompany-

ing their development systems for the appropriate

information.

PIC18F87J50 FAMILY

27.0 DEVELOPMENT SUPPORT

The PIC® microcontrollers are supported with a full

range of hardware and software development tools:

• Integrated Development Environment

- MPLAB® IDE Software

• Assemblers/Compilers/Linkers

- MPASMTM Assembler

- MPLAB C18 and MPLAB C30 C Compilers

-MPLINK

TM Object Linker/

MPLIBTM Object Librarian

- MPLAB ASM30 Assembler/Linker/Library

• Simulators

- MPLAB SIM Software Simulator

•Emulators

- MPLAB ICE 2000 In-Circuit Emulator

- MPLAB REAL ICE™ In-Circuit Emulator

• In-Circuit Debugger

- MPLAB ICD 2

• Device Programmers

- PICSTART® Plus Development Programmer

- MPLAB PM3 Device Programmer

- PICkit™ 2 Development Programmer

• Low-Cost Demonstration and Development

Boards and Evaluation Kits

27.1 MPLAB Integrated Development

Environment Software

The MPLAB IDE software brings an ease of software

development previously unseen in the 8/16-bit micro-

controller market. The MPLAB IDE is a Windows®

operating system-based application that contains:

• A single graphical interface to all debugging tools

- Simulator

- Programmer (sold separately)

- Emulator (sold separately)

- In-Circuit Debugger (sold separately)

• A full-featured editor with color-coded context

• A multiple project manager

• Customizable data windows with direct edit of

contents

• High-level source code debugging

• Visual device initializer for easy register

initialization

• Mouse over variable inspection

• Drag and drop variables from source to watch

windows

• Extensive on-line help

• Integration of select third party tools, such as

HI-TECH Software C Compilers and IAR

C Compilers

The MPLAB IDE allows you to:

• Edit your source files (either assembly or C)

• One touch assemble (or compile) and download

to PIC MCU emulator and simulator tools

(automatically updates all project information)

• Debug using:

- Source files (assembly or C)

- Mixed assembly and C

- Machine code

MPLAB IDE supports multiple debugging tools in a

single development paradigm, from the cost-effective

simulators, through low-cost in-circuit debuggers, to

full-featured emulators. This eliminates the learning

curve when upgrading to tools with increased flexibility

and power.

PIC18F87J50 FAMILY

27.2 MPASM Assembler

The MPASM Assembler is a full-featured, universal

macro assembler for all PIC MCUs.

The MPASM Assembler generates relocatable object

files for the MPLINK Object Linker, Intel® standard HEX

files, MAP files to detail memory usage and symbol

reference, absolute LST files that contain source lines

and generated machine code and COFF files for

debugging.

The MPASM Assembler features include:

• Integration into MPLAB IDE projects

• User-defined macros to streamline

assembly code

• Conditional assembly for multi-purpose

source files

• Directives that allow complete control over the

assembly process

27.3 MPLAB C18 and MPLAB C30

C Compilers

The MPLAB C18 and MPLAB C30 Code Development

Systems are complete ANSI C compilers for

Microchip’s PIC18 and PIC24 families of microcontrol-

lers and the dsPIC30 and dsPIC33 family of digital sig-

nal controllers. These compilers provide powerful

integration capabilities, superior code optimization and

ease of use not found with other compilers.

For easy source level debugging, the compilers provide

symbol information that is optimized to the MPLAB IDE

debugger.

27.4 MPLINK Object Linker/

MPLIB Object Librarian

The MPLINK Object Linker combines relocatable

objects created by the MPASM Assembler and the

MPLAB C18 C Compiler. It can link relocatable objects

from precompiled libraries, using directives from a

linker script.

The MPLIB Object Librarian manages the creation and

modification of library files of precompiled code. When

a routine from a library is called from a source file, only

the modules that contain that routine will be linked in

with the application. This allows large libraries to be

used efficiently in many different applications.

The object linker/library features include:

• Efficient linking of single libraries instead of many

smaller files

• Enhanced code maintainability by grouping

related modules together

• Flexible creation of libraries with easy module

listing, replacement, deletion and extraction

27.5 MPLAB ASM30 Assembler, Linker

and Librarian

MPLAB ASM30 Assembler produces relocatable

machine code from symbolic assembly language for

dsPIC30F devices. MPLAB C30 C Compiler uses the

assembler to produce its object file. The assembler

generates relocatable object files that can then be

archived or linked with other relocatable object files and

archives to create an executable file. Notable features

of the assembler include:

• Support for the entire dsPIC30F instruction set

• Support for fixed-point and floating-point data

• Command line interface

• Rich directive set

• Flexible macro language

• MPLAB IDE compatibility

27.6 MPLAB SIM Software Simulator

The MPLAB SIM Software Simulator allows code

development in a PC-hosted environment by simulat-

ing the PIC MCUs and dsPIC® DSCs on an instruction

level. On any given instruction, the data areas can be

examined or modified and stimuli can be applied from

a comprehensive stimulus controller. Registers can be

logged to files for further run-time analysis. The trace

buffer and logic analyzer display extend the power of

the simulator to record and track program execution,

actions on I/O, most peripherals and internal registers.

The MPLAB SIM Software Simulator fully supports

symbolic debugging using the MPLAB C18 and

MPLAB C30 C Compilers, and the MPASM and

MPLAB ASM30 Assemblers. The software simulator

offers the flexibility to develop and debug code outside

of the hardware laboratory environment, making it an

excellent, economical software development tool.

PIC18F87J50 FAMILY

27.7 MPLAB ICE 2000

High-Performance

In-Circuit Emulator

The MPLAB ICE 2000 In-Circuit Emulator is intended

to provide the product development engineer with a

complete microcontroller design tool set for PIC

microcontrollers. Software control of the MPLAB ICE

2000 In-Circuit Emulator is advanced by the MPLAB

Integrated Development Environment, which allows

editing, building, downloading and source debugging

from a single environment.

The MPLAB ICE 2000 is a full-featured emulator

system with enhanced trace, trigger and data monitor-

ing features. Interchangeable processor modules allow

the system to be easily reconfigured for emulation of

different processors. The architecture of the MPLAB

ICE 2000 In-Circuit Emulator allows expansion to

support new PIC microcontrollers.

The MPLAB ICE 2000 In-Circuit Emulator system has

been designed as a real-time emulation system with

advanced features that are typically found on more

expensive development tools. The PC platform and

Microsoft® Windows® 32-bit operating system were

chosen to best make these features available in a

simple, unified application.

27.8 MPLAB REAL ICE In-Circuit

Emulator System

MPLAB REAL ICE In-Circuit Emulator System is

Microchip’s next generation high-speed emulator for

Microchip Flash DSC® and MCU devices. It debugs and

programs PIC® and dsPIC® Flash microcontrollers with

the easy-to-use, powerful graphical user interface of the

MPLAB Integrated Development Environment (IDE),

included with each kit.

The MPLAB REAL ICE probe is connected to the design

engineer’s PC using a high-speed USB 2.0 interface and

is connected to the target with either a connector

compatible with the popular MPLAB ICD 2 system

(RJ11) or with the new high speed, noise tolerant, low-

voltage differential signal (LVDS) interconnection

(CAT5).

MPLAB REAL ICE is field upgradeable through future

firmware downloads in MPLAB IDE. In upcoming

releases of MPLAB IDE, new devices will be supported,

and new features will be added, such as software break-

points and assembly code trace. MPLAB REAL ICE

offers significant advantages over competitive emulators

including low-cost, full-speed emulation, real-time

variable watches, trace analysis, complex breakpoints, a

ruggedized probe interface and long (up to three meters)

interconnection cables.

27.9 MPLAB ICD 2 In-Circuit Debugger

Microchip’s In-Circuit Debugger, MPLAB ICD 2, is a

powerful, low-cost, run-time development tool,

connecting to the host PC via an RS-232 or high-speed

USB interface. This tool is based on the Flash PIC

MCUs and can be used to develop for these and other

PIC MCUs and dsPIC DSCs. The MPLAB ICD 2 utilizes

the in-circuit debugging capability built into the Flash

devices. This feature, along with Microchip’s In-Circuit

Serial ProgrammingTM (ICSPTM) protocol, offers cost-

effective, in-circuit Flash debugging from the graphical

user interface of the MPLAB Integrated Development

Environment. This enables a designer to develop and

debug source code by setting breakpoints, single step-

ping and watching variables, and CPU status and

peripheral registers. Running at full speed enables

testing hardware and applications in real time. MPLAB

ICD 2 also serves as a development programmer for

selected PIC devices.

27.10 MPLAB PM3 Device Programmer

The MPLAB PM3 Device Programmer is a universal,

CE compliant device programmer with programmable

voltage verification at VDDMIN and VDDMAX for

maximum reliability. It features a large LCD display

(128 x 64) for menus and error messages and a modu-

lar, detachable socket assembly to support various

package types. The ICSP™ cable assembly is included

as a standard item. In Stand-Alone mode, the MPLAB

PM3 Device Programmer can read, verify and program

PIC devices without a PC connection. It can also set

code protection in this mode. The MPLAB PM3

connects to the host PC via an RS-232 or USB cable.

The MPLAB PM3 has high-speed communications and

optimized algorithms for quick programming of large

memory devices and incorporates an SD/MMC card for

file storage and secure data applications.

PIC18F87J50 FAMILY

27.11 PICSTART Plus Development

Programmer

The PICSTART Plus Development Programmer is an

easy-to-use, low-cost, prototype programmer. It

connects to the PC via a COM (RS-232) port. MPLAB

Integrated Development Environment software makes

using the programmer simple and efficient. The

PICSTART Plus Development Programmer supports

most PIC devices in DIP packages up to 40 pins.

Larger pin count devices, such as the PIC16C92X and

PIC17C76X, may be supported with an adapter socket.

The PICSTART Plus Development Programmer is CE

compliant.

27.12 PICkit 2 Development Programmer

The PICkit™ 2 Development Programmer is a low-cost

programmer and selected Flash device debugger with

an easy-to-use interface for programming many of

Microchip’s baseline, mid-range and PIC18F families of

Flash memory microcontrollers. The PICkit 2 Starter Kit

includes a prototyping development board, twelve

sequential lessons, software and HI-TECH’s PICC™

Lite C compiler, and is designed to help get up to speed

quickly using PIC® microcontrollers. The kit provides

everything needed to program, evaluate and develop

applications using Microchip’s powerful, mid-range

Flash memory family of microcontrollers.

27.13 Demonstration, Development and

Evaluation Boards

A wide variety of demonstration, development and

evaluation boards for various PIC MCUs and dsPIC

DSCs allows quick application development on fully func-

tional systems. Most boards include prototyping areas for

adding custom circuitry and provide application firmware

and source code for examination and modification.

The boards support a variety of features, including LEDs,

temperature sensors, switches, speakers, RS-232

interfaces, LCD displays, potentiometers and additional

EEPROM memory.

The demonstration and development boards can be

used in teaching environments, for prototyping custom

circuits and for learning about various microcontroller

applications.

In addition to the PICDEM™ and dsPICDEM™ demon-

stration/development board series of circuits, Microchip

has a line of evaluation kits and demonstration software

for analog filter design, KEELOQ® security ICs, CAN,

IrDA®, PowerSmart® battery management, SEEVAL®

evaluation system, Sigma-Delta ADC, flow rate

sensing, plus many more.

Check the Microchip web page (www.microchip.com)

and the latest “Product Selector Guide” (DS00148) for

the complete list of demonstration, development and

evaluation kits.

PIC18F87J50 FAMILY

28.0 ELECTRICAL CHARACTERISTICS

Absolute Maximum Ratings(†)

Ambient temperature under bias.............................................................................................................-40°C to +100°C

Storage temperature .............................................................................................................................. -65°C to +150°C

Voltage on any digital only I/O pin or MCLR with respect to VSS (except VDD) ........................................... -0.3V to 6.0V

Voltage on any combined digital and analog pin with respect to VSS (except VDD)........................ -0.3V to (VDD + 0.3V)

Voltage on VDDCORE with respect to VSS ................................................................................................... -0.3V to 2.75V

Voltage on VDD with respect to VSS ........................................................................................................... -0.3V to 4.0V

Voltage on VUSB with respect to VSS................................................................................... (VDD – 0.3V) to (VDD + 0.3V)

Total power dissipation (Note 1) ...............................................................................................................................1.0W

Maximum current out of VSS pin ...........................................................................................................................300 mA

Maximum current into VDD pin ..............................................................................................................................250 mA

Maximum output current sunk by any PORTB and PORTC I/O pin........................................................................25 mA

Maximum output current sunk by any PORTD, PORTE and PORTJ I/O pin............................................................8 mA

Maximum output current sunk by any PORTA, PORTF, PORTG and PORTH I/O pin .............................................2 mA

Maximum output current sourced by any PORTB and PORTC I/O pin ..................................................................25 mA

Maximum output current sourced by any PORTD, PORTE and PORTJ I/O pin.......................................................8 mA

Maximum output current sourced by any PORTA, PORTF, PORTG and PORTH I/O pin ........................................2 mA

Maximum current sunk by all ports .......................................................................................................................200 mA

Maximum current sourced by all ports ..................................................................................................................200 mA

Note 1: Power dissipation is calculated as follows:

Pdis = VDD x {IDD – ∑ IOH} + ∑ {(VDD – VOH) x IOH} + ∑(VOL x IOL)

† NOTICE: Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the

device. This is a stress rating only and functional operation of the device at those or any other conditions above those

indicated in the operation listings of this specification is not implied. Exposure to maximum rating conditions for

extended periods may affect device reliability.

PIC18F87J50 FAMILY

FIGURE 28-1: PIC18F87J50 FAMILY VDD FREQUENCY GRAPH (INDUSTRIAL)

FIGURE 28-2: PIC18F87J50 FAMILY VDDCORE FREQUENCY GRAPH (INDUSTRIAL)(1)

Note 1: When the USB module is enabled, VUSB and VDD should be connected together and provided

3.0V-3.6V while VDDCORE must be ≥ 2.45V. When the core regulator is enabled and VDD is ≥ 3.0V, it

will always regulate to ≥ 2.45V. When the USB module is not enabled, VUSB and VDD should still be

connected together, but the wider limits shaded in gray apply.

Frequency

Voltage (VDD)

4.0V

2.0V

48 MHz

3.5V

3.0V

2.5V

3.6V

8 MHz

PIC18F87J50 Family

2.35V

(Note 1)

Frequency

Voltage (VDDCORE)

3.00V

2.00V

48 MHz

2.75V

2.50V

2.25V

2.75V

8 MHz

2.35V

Note 1: VDD and VDDCORE must be maintained so that VDDCORE ≤ VDD.

2: When the USB module is enabled, VUSB and VDD should be connected together and provided

3.0V-3.6V while VDDCORE must be ≥ 2.45V. When the core regulator is enabled and VDD is ≥ 3.0V,

it will always regulate to ≥ 2.45V. When the USB module is not enabled, VUSB and VDD should still

be connected together, but the wider limits shaded in gray apply.

2.45V(2)

PIC18F87J50 Family

PIC18F87J50 FAMILY

28.1 DC Characteristics: Supply Voltage

PIC18F87J50 Family (Industrial)

PIC18F87J50 Family

(Industrial)

Standard Operating Conditions (unless otherwise stated)

Operating temperature -40°C ≤ TA ≤ +85°C for industrial

Param

No. Symbol Characteristic Min Typ Max Units Conditions

D001 VDD Supply Voltage VDDCORE

2.0

—

3.6

ENVREG = 0

ENVREG = 1

D001B VDDCORE External Supply for

Microcontroller Core

2.0 — 2.75 V ENVREG = 0

D001C AVDD Analog Supply Voltage VDD – 0.3 — VDD + 0.3 V

D001D AVSS Analog Ground Potential VSS – 0.3 — VSS + 0.3 V

D001E VUSB USB Supply Voltage 3.0 3.3 3.6 V USB module enabled(2)

D002 VDR RAM Data Retention

Voltage(1)

1.5 — — V

D003 VPOR VDD Start Voltage

to ensure internal

Power-on Reset signal

— — 0.7 V See Section 4.3 “Power-on

Reset (POR)” for details

D004 SVDD VDD Rise Rate

to ensure internal

Power-on Reset signal

0.05 — — V/ms See Section 4.3 “Power-on

Reset (POR)” for details

D005 VBOR Brown-out Reset Voltage —1.8— V

Note 1: This is the limit to which VDD can be lowered in Sleep mode, or during a device Reset, without losing RAM data.

2: VUSB should be connected to VDD. When the USB module is disabled, the limits of Figure 28-1 apply.

PIC18F87J50 FAMILY

28.2 DC Characteristics: Power-Down and Supply Current

PIC18F87J50 Family (Industrial)

PIC18F87J50 Family

(Industrial)

Standard Operating Conditions (unless otherwise stated)

Operating temperature -40°C ≤ T

A ≤ +85°C for industrial

Param

No. Device Typ Max Units Conditions

Power-Down Current (IPD)(1)

All devices 0.5 1.4 μA -40°C VDD = 2.0V(4),

VDDCORE = 2.0V

(Sleep mode)

0.5 1.4 μA +25°C

5.5 10.2 μA +85°C

All devices 0.6 1.5 μA -40°C VDD = 2.5V(4),

VDDCORE = 2.5V

(Sleep mode)

0.6 1.5 μA +25°C

6.8 12.6 μA +85°C

All devices 2.9 7 μA -40°C

VDD = 3.3V(5)

(Sleep mode)

3.6 7 μA +25°C

9.6 19 μA +85°C

Note 1: The power-down current in Sleep mode does not depend on the oscillator type. Power-down current is measured with

the part in Sleep mode, with all I/O pins in high-impedance state and tied to VDD or VSS and all features that add delta

current disabled (such as WDT, Timer1 oscillator, BOR, etc.).

2: The supply current is mainly a function of operating voltage, frequency and mode. Other factors, such as I/O pin loading

and switching rate, oscillator type and circuit, internal code execution pattern and temperature, also have an impact on

the current consumption. All features that add delta current are disabled (USB module, WDT, etc.).

The test conditions for all IDD measurements in active operation mode are:

OSC1 = external square wave, from rail-to-rail; all I/O pins tri-stated, pulled to VDD;

MCLR = VDD; WDT disabled unless otherwise specified.

3: Standard, low-cost 32 kHz crystals have an operating temperature range of -10°C to +70°C. Extended temperature

crystals are available at a much higher cost.

4: Voltage regulator disabled (ENVREG = 0, tied to VSS).

5: Voltage regulator enabled (ENVREG = 1, tied to VDD), REGSLP = 1.

6: This is the module differential current when the USB module is enabled and clocked at 48 MHz, but with no USB cable

attached. When the USB cable is attached or data is being transmitted, the current consumption may be much higher

(see Section 22.6.4 “USB Transceiver Current Consumption”). During USB Suspend mode (USBEN = 1,

SUSPND = 1, bus in Idle state), the USB module current will be dominated by the D+ or D- pull-up resistor. The

integrated pull-up resistors use “resistor switching” according to the resistor_ecn supplement to the USB 2.0

specifications, and therefore, may be as low as 900Ω during Idle conditions.

PIC18F87J50 FAMILY

Supply Current (IDD)(2)

All devices 5 14.2 μA-40°C

VDD = 2.0V,

VDDCORE = 2.0V(4)

FOSC = 31 kHz

(RC_RUN mode,

internal oscillator source)

5.5 14.2 μA +25°C

10 19.0 μA +85°C

All devices 6.8 16.5 μA-40°C

VDD = 2.5V,

VDDCORE = 2.5V(4)

7.6 16.5 μA +25°C

14 22.4 μA +85°C

All devices 37 84 μA-40°C

51 84 μA +25°C VDD = 3.3V(5)

72 108 μA +85°C

All devices 0.43 0.82 mA -40°C

VDD = 2.0V,

VDDCORE = 2.0V(4)

FOSC = 1 MHz

(RC_RUN mode,

internal oscillator source)

0.47 0.82 mA +25°C

0.52 0.95 mA +85°C

All devices 0.52 0.98 mA -40°C

VDD = 2.5V,

VDDCORE = 2.5V(4)

0.57 0.98 mA +25°C

0.63 1.10 mA +85°C

All devices 0.59 0.96 mA -40°C

0.65 0.96 mA +25°C VDD = 3.3V(5)

0.72 1.18 mA +85°C

All devices 0.88 1.45 mA -40°C

VDD = 2.0V,

VDDCORE = 2.0V(4)

FOSC = 4 MHz

(RC_RUN mode,

internal oscillator source)

1.0 1.45 mA +25°C

1.1 1.58 mA +85°C

All devices 1.2 1.72 mA -40°C

VDD = 2.5V,

VDDCORE = 2.5V(4)

1.3 1.72 mA +25°C

1.4 1.85 mA +85°C

All devices 1.3 2.87 mA -40°C

1.4 2.87 mA +25°C VDD = 3.3V(5)

1.5 2.96 mA +85°C

28.2 DC Characteristics: Power-Down and Supply Current

PIC18F87J50 Family (Industrial) (Continued)