HCS08
Microcontrollers
freescale.com
MC9S08RC8/16/32/60
MC9S08RD8/16/32/60
MC9S08RE8/16/32/60
MC9S08RG32/60
Data Sheet
MC9S08RG60/D
Rev. 1.11
06/2005
MC9S08RG60 Data Sheet
Covers: MC9S08RC8/16/32/60
MC9S08RD8/16/32/60
MC9S08RE8/16/32/60
MC9S08RG32/60
MC9S08RG60/D
Rev. 1.11
06/2005
Revision History
To provide the most up-to-date information, the revision of our documents on the World Wide Web will
be the most current. Your printed copy may be an earlier revision. To verify you have the latest information
available, refer to:
http://freescale.com
The following revision history table summarizes changes contained in this document.
Version
Number
Revision
Date Description of Changes
1.11 06/2005
Added 48 QFN package and official mechanical drawings; suppled
TBD values for IRO VOL; updated tRTI values; re-emphasized that
KBI2 will not wake the MCU from stop2 mode.
This product contains SuperFlash® technology licensed from SST.
Freescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc.
© Freescale Semiconductor, Inc., 2005. All rights reserved.
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 5
List of Chapters
Chapter 1 Introduction.............................................................................15
Chapter 2 Pins and Connections ............................................................19
Chapter 3 Modes of Operation ................................................................29
Chapter 4 Memory....................................................................................35
Chapter 5 Resets, Interrupts, and System Configuration ....................57
Chapter 6 Parallel Input/Output ..............................................................73
Chapter 7 Central Processor Unit (S08CPUV2) .....................................87
Chapter 8 Carrier Modulator Timer (S08CMTV1).................................107
Chapter 9 Keyboard Interrupt (S08KBIV1) ...........................................123
Chapter 10 Timer/PWM Module (S08TPMV1).........................................129
Chapter 11 Serial Communications Interface (S08SCIV1)....................145
Chapter 12 Serial Communications Interface (S08SCIV1)....................147
Chapter 13 Serial Peripheral Interface (S08SPIV3) ...............................163
Chapter 14 Analog Comparator (S08ACMPV1) .....................................179
Chapter 15 Development Support ..........................................................183
Appendix A Electrical Characteristics.....................................................205
Appendix B Ordering Information and Mechanical Drawings...............219
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 7
Chapter 1
Introduction
1.1 Overview .........................................................................................................................................15
1.2 Features ...........................................................................................................................................15
1.2.1 Devices in the MC9S08RC/RD/RE/RG Series ..............................................................16
1.3 MCU Block Diagram ......................................................................................................................17
1.4 System Clock Distribution ..............................................................................................................18
Chapter 2
Pins and Connections
2.1 Introduction .....................................................................................................................................19
2.2 Device Pin Assignment ...................................................................................................................19
2.3 Recommended System Connections ...............................................................................................21
2.3.1 Power ..............................................................................................................................23
2.3.2 Oscillator ........................................................................................................................23
2.3.3 PTD1/RESET .................................................................................................................23
2.3.4 Background/Mode Select (PTD0/BKGD/MS) ...............................................................24
2.3.5 IRO Pin Description .......................................................................................................24
2.3.6 General-Purpose I/O and Peripheral Ports .....................................................................24
2.3.7 Signal Properties Summary ............................................................................................25
Chapter 3
Modes of Operation
3.1 Introduction .....................................................................................................................................29
3.2 Features ...........................................................................................................................................29
3.3 Run Mode ........................................................................................................................................29
3.4 Active Background Mode ................................................................................................................29
3.5 Wait Mode .......................................................................................................................................30
3.6 Stop Modes ......................................................................................................................................31
3.6.1 Stop1 Mode ....................................................................................................................31
3.6.2 Stop2 Mode ....................................................................................................................31
3.6.3 Stop3 Mode ....................................................................................................................32
3.6.4 Active BDM Enabled in Stop Mode ...............................................................................33
3.6.5 LVD Reset Enabled ........................................................................................................33
3.6.6 On-Chip Peripheral Modules in Stop Mode ...................................................................33
Contents
Section Number Title Page
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
8 Freescale Semiconductor
Section Number Title Page
Chapter 4
Memory
4.1 MC9S08RC/RD/RE/RG Memory Map ..........................................................................................35
4.1.1 Reset and Interrupt Vector Assignments ........................................................................36
4.2 Register Addresses and Bit Assignments ........................................................................................38
4.3 RAM ................................................................................................................................................42
4.4 FLASH ............................................................................................................................................42
4.4.1 Features ...........................................................................................................................43
4.4.2 Program and Erase Times ...............................................................................................43
4.4.3 Program and Erase Command Execution .......................................................................44
4.4.4 Burst Program Execution ...............................................................................................45
4.4.5 Access Errors ..................................................................................................................46
4.4.6 FLASH Block Protection ...............................................................................................47
4.4.7 Vector Redirection ..........................................................................................................48
4.5 Security ............................................................................................................................................48
4.6 FLASH Registers and Control Bits .................................................................................................49
4.6.1 FLASH Clock Divider Register (FCDIV) ......................................................................49
4.6.2 FLASH Options Register (FOPT and NVOPT) .............................................................51
4.6.3 FLASH Configuration Register (FCNFG) .....................................................................51
4.6.4 FLASH Protection Register (FPROT and NVPROT) ....................................................52
4.6.5 FLASH Status Register (FSTAT) ...................................................................................54
4.6.6 FLASH Command Register (FCMD) ............................................................................55
Chapter 5
Resets, Interrupts, and System Configuration
5.1 Introduction .....................................................................................................................................57
5.2 Features ...........................................................................................................................................57
5.3 MCU Reset ......................................................................................................................................57
5.4 Computer Operating Properly (COP) Watchdog .............................................................................58
5.5 Interrupts .........................................................................................................................................58
5.5.1 Interrupt Stack Frame .....................................................................................................59
5.5.2 External Interrupt Request (IRQ) Pin .............................................................................60
5.5.2.1 Pin Configuration Options ..............................................................................60
5.5.2.2 Edge and Level Sensitivity ..............................................................................61
5.5.3 Interrupt Vectors, Sources, and Local Masks .................................................................61
5.6 Low-Voltage Detect (LVD) System ................................................................................................62
5.6.1 Power-On Reset Operation .............................................................................................63
5.6.2 LVD Reset Operation .....................................................................................................63
5.6.3 LVD Interrupt and Safe State Operation ........................................................................63
5.6.4 Low-Voltage Warning (LVW) ........................................................................................63
5.7 Real-Time Interrupt (RTI) ...............................................................................................................64
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 9
Section Number Title Page
5.8 Reset, Interrupt, and System Control Registers and Control Bits ...................................................64
5.8.1 Interrupt Pin Request Status and Control Register (IRQSC) .........................................64
5.8.2 System Reset Status Register (SRS) ...............................................................................65
5.8.3 System Background Debug Force Reset Register (SBDFR) ..........................................67
5.8.4 System Options Register (SOPT) ...................................................................................68
5.8.5 System Device Identification Register (SDIDH, SDIDL) ..............................................69
5.8.6 System Real-Time Interrupt Status and Control Register (SRTISC) .............................70
5.8.7 System Power Management Status and Control 1 Register (SPMSC1) .........................71
5.8.8 System Power Management Status and Control 2 Register (SPMSC2) .........................72
Chapter 6
Parallel Input/Output
6.1 Introduction .....................................................................................................................................73
6.2 Features ...........................................................................................................................................73
6.3 Pin Descriptions ..............................................................................................................................74
6.3.1 Port A ..............................................................................................................................74
6.3.2 Port B ..............................................................................................................................74
6.3.3 Port C ..............................................................................................................................75
6.3.4 Port D ..............................................................................................................................75
6.3.5 Port E ..............................................................................................................................76
6.4 Parallel I/O Controls ........................................................................................................................76
6.4.1 Data Direction Control ...................................................................................................76
6.4.2 Internal Pullup Control ...................................................................................................77
6.5 Stop Modes ......................................................................................................................................77
6.6 Parallel I/O Registers and Control Bits ...........................................................................................77
6.6.1 Port A Registers (PTAD, PTAPE, and PTADD) ............................................................78
6.6.2 Port B Registers (PTBD, PTBPE, and PTBDD) ............................................................79
6.6.3 Port C Registers (PTCD, PTCPE, and PTCDD) ............................................................81
6.6.4 Port D Registers (PTDD, PTDPE, and PTDDD) ...........................................................82
6.6.5 Port E Registers (PTED, PTEPE, and PTEDD) .............................................................84
Chapter 7
Central Processor Unit (S08CPUV2)
7.1 Introduction .....................................................................................................................................87
7.1.1 Features ...........................................................................................................................87
7.2 Programmer’s Model and CPU Registers .......................................................................................88
7.2.1 Accumulator (A) .............................................................................................................88
7.2.2 Index Register (H:X) ......................................................................................................88
7.2.3 Stack Pointer (SP) ...........................................................................................................89
7.2.4 Program Counter (PC) ....................................................................................................89
7.2.5 Condition Code Register (CCR) .....................................................................................89
7.3 Addressing Modes ...........................................................................................................................90
7.3.1 Inherent Addressing Mode (INH) ..................................................................................91
7.3.2 Relative Addressing Mode (REL) ..................................................................................91
7.3.3 Immediate Addressing Mode (IMM) .............................................................................91
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
10 Freescale Semiconductor
Section Number Title Page
7.3.4 Direct Addressing Mode (DIR) ......................................................................................91
7.3.5 Extended Addressing Mode (EXT) ................................................................................91
7.3.6 Indexed Addressing Mode ..............................................................................................91
7.3.6.1 Indexed, No Offset (IX) ..................................................................................92
7.3.6.2 Indexed, No Offset with Post Increment (IX+) ...............................................92
7.3.6.3 Indexed, 8-Bit Offset (IX1) .............................................................................92
7.3.6.4 Indexed, 8-Bit Offset with Post Increment (IX1+) .........................................92
7.3.6.5 Indexed, 16-Bit Offset (IX2) ...........................................................................92
7.3.6.6 SP-Relative, 8-Bit Offset (SP1) ......................................................................92
7.3.6.7 SP-Relative, 16-Bit Offset (SP2) ....................................................................92
7.4 Special Operations ...........................................................................................................................92
7.4.1 Reset Sequence ...............................................................................................................93
7.4.2 Interrupt Sequence ..........................................................................................................93
7.4.3 Wait Mode Operation .....................................................................................................94
7.4.4 Stop Mode Operation .....................................................................................................94
7.4.5 BGND Instruction ..........................................................................................................94
7.5 HCS08 Instruction Set Summary ....................................................................................................95
Chapter 8
Carrier Modulator Timer (S08CMTV1)
8.1 Introduction ...................................................................................................................................107
8.2 Features .........................................................................................................................................108
8.3 CMT Block Diagram .....................................................................................................................108
8.4 Pin Description ..............................................................................................................................108
8.5 Functional Description ..................................................................................................................109
8.5.1 Carrier Generator ..........................................................................................................110
8.5.2 Modulator .....................................................................................................................112
8.5.2.1 Time Mode ....................................................................................................113
8.5.2.2 Baseband Mode .............................................................................................114
8.5.2.3 FSK Mode .....................................................................................................114
8.5.3 Extended Space Operation ...........................................................................................115
8.5.3.1 EXSPC Operation in Time Mode .................................................................115
8.5.3.2 EXSPC Operation in FSK Mode ..................................................................116
8.5.4 Transmitter ....................................................................................................................116
8.5.5 CMT Interrupts .............................................................................................................117
8.5.6 Wait Mode Operation ...................................................................................................117
8.5.7 Stop Mode Operation ...................................................................................................117
8.5.8 Background Mode Operation .......................................................................................118
8.6 CMT Registers and Control Bits ...................................................................................................118
8.6.1 Carrier Generator Data Registers (CMTCGH1, CMTCGL1, CMTCGH2, and
CMTCGL2) ..............................................................................................................118
8.6.2 CMT Output Control Register (CMTOC) ....................................................................120
8.6.3 CMT Modulator Status and Control Register (CMTMSC) ..........................................121
8.6.4 CMT Modulator Data Registers (CMTCMD1, CMTCMD2, CMTCMD3, and
CMTCMD4) .............................................................................................................122
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 11
Section Number Title Page
Chapter 9
Keyboard Interrupt (S08KBIV1)
9.1 Introduction ...................................................................................................................................123
9.2 KBI Block Diagram ......................................................................................................................125
9.3 Keyboard Interrupt (KBI) Module ................................................................................................125
9.3.1 Pin Enables ...................................................................................................................125
9.3.2 Edge and Level Sensitivity ...........................................................................................125
9.3.3 KBI Interrupt Controls .................................................................................................126
9.4 KBI Registers and Control Bits .....................................................................................................126
9.4.1 KBI x Status and Control Register (KBIxSC) ..............................................................127
9.4.2 KBI x Pin Enable Register (KBIxPE) ..........................................................................128
Chapter 10
Timer/PWM Module (S08TPMV1)
10.1 Introduction ...................................................................................................................................129
10.2 Features .........................................................................................................................................129
10.3 TPM Block Diagram .....................................................................................................................131
10.4 Pin Descriptions ............................................................................................................................132
10.4.1 External TPM Clock Sources .......................................................................................132
10.4.2 TPM1CHn — TPM1 Channel n I/O Pins .....................................................................132
10.5 Functional Description ..................................................................................................................132
10.5.1 Counter .........................................................................................................................133
10.5.2 Channel Mode Selection ...............................................................................................134
10.5.2.1 Input Capture Mode ......................................................................................134
10.5.2.2 Output Compare Mode .................................................................................134
10.5.2.3 Edge-Aligned PWM Mode ...........................................................................134
10.5.3 Center-Aligned PWM Mode ........................................................................................135
10.6 TPM Interrupts ..............................................................................................................................137
10.6.1 Clearing Timer Interrupt Flags .....................................................................................137
10.6.2 Timer Overflow Interrupt Description ..........................................................................137
10.6.3 Channel Event Interrupt Description ............................................................................137
10.6.4 PWM End-of-Duty-Cycle Events .................................................................................138
10.7 TPM Registers and Control Bits ...................................................................................................138
10.7.1 Timer Status and Control Register (TPM1SC) .............................................................139
10.7.2 Timer Counter Registers (TPM1CNTH:TPM1CNTL) ................................................140
10.7.3 Timer Counter Modulo Registers (TPM1MODH:TPM1MODL) ................................141
10.7.4 Timer Channel n Status and Control Register (TPM1CnSC) .......................................142
10.7.5 Timer Channel Value Registers (TPM1CnVH:TPM1CnVL) .......................................143
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
12 Freescale Semiconductor
Section Number Title Page
Chapter 11
Serial Communications Interface (S08SCIV1)
11.1 Introduction ...................................................................................................................................145
Chapter 12
Serial Communications Interface (S08SCIV1)
12.1 Introduction ...................................................................................................................................147
12.1.1 Features .........................................................................................................................147
12.1.2 Modes of Operation ......................................................................................................147
12.1.3 Block Diagram ..............................................................................................................148
12.2 Register Definition ........................................................................................................................150
12.2.1 SCI Baud Rate Registers (SCI1BDH, SCI1BHL) ........................................................150
12.2.2 SCI Control Register 1 (SCI1C1) .................................................................................151
12.2.3 SCI Control Register 2 (SCI1C2) .................................................................................152
12.2.4 SCI Status Register 1 (SCI1S1) ....................................................................................153
12.2.5 SCI Status Register 2 (SCI1S2) ....................................................................................155
12.2.6 SCI Control Register 3 (SCI1C3) .................................................................................155
12.2.7 SCI Data Register (SCI1D) ..........................................................................................156
12.3 Functional Description ..................................................................................................................157
12.3.1 Baud Rate Generation ...................................................................................................157
12.3.2 Transmitter Functional Description ..............................................................................157
12.3.2.1 Send Break and Queued Idle .........................................................................158
12.3.3 Receiver Functional Description ..................................................................................158
12.3.3.1 Data Sampling Technique .............................................................................159
12.3.3.2 Receiver Wakeup Operation .........................................................................159
12.3.4 Interrupts and Status Flags ...........................................................................................160
12.3.5 Additional SCI Functions .............................................................................................161
12.3.5.1 8- and 9-Bit Data Modes ...............................................................................161
12.3.5.2 Stop Mode Operation ....................................................................................161
12.3.5.3 Loop Mode ....................................................................................................161
12.3.5.4 Single-Wire Operation ..................................................................................162
Chapter 13
Serial Peripheral Interface (S08SPIV3)
13.1 Features .........................................................................................................................................164
13.2 Block Diagrams .............................................................................................................................164
13.2.1 SPI System Block Diagram ..........................................................................................164
13.2.2 SPI Module Block Diagram .........................................................................................165
13.2.3 SPI Baud Rate Generation ............................................................................................167
13.3 Functional Description ..................................................................................................................167
13.3.1 SPI Clock Formats ........................................................................................................168
13.3.2 SPI Pin Controls ...........................................................................................................170
13.3.2.1 SPSCK1 — SPI Serial Clock ........................................................................170
13.3.2.2 MOSI1 — Master Data Out, Slave Data In ..................................................170
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 13
Section Number Title Page
13.3.2.3 MISO1 — Master Data In, Slave Data Out ..................................................170
13.3.2.4 SS1 — Slave Select .......................................................................................170
13.3.3 SPI Interrupts ................................................................................................................171
13.3.4 Mode Fault Detection ...................................................................................................171
13.4 SPI Registers and Control Bits ......................................................................................................171
13.4.1 SPI Control Register 1 (SPI1C1) ..................................................................................172
13.4.2 SPI Control Register 2 (SPI1C2) ..................................................................................173
13.4.3 SPI Baud Rate Register (SPI1BR) ...............................................................................174
13.4.4 SPI Status Register (SPI1S) ..........................................................................................176
13.4.5 SPI Data Register (SPI1D) ...........................................................................................177
Chapter 14
Analog Comparator (S08ACMPV1)
14.1 Features .........................................................................................................................................180
14.2 Block Diagram ..............................................................................................................................180
14.3 Pin Description ..............................................................................................................................180
14.4 Functional Description ..................................................................................................................181
14.4.1 Interrupts .......................................................................................................................181
14.4.2 Wait Mode Operation ...................................................................................................181
14.4.3 Stop Mode Operation ...................................................................................................181
14.4.4 Background Mode Operation .......................................................................................181
14.5 ACMP Status and Control Register (ACMP1SC) .........................................................................182
Chapter 15
Development Support
15.1 Introduction ...................................................................................................................................183
15.1.1 Features .........................................................................................................................183
15.2 Background Debug Controller (BDC) ..........................................................................................184
15.2.1 BKGD Pin Description .................................................................................................184
15.2.2 Communication Details ................................................................................................185
15.2.3 BDC Commands ...........................................................................................................189
15.2.4 BDC Hardware Breakpoint ..........................................................................................191
15.3 On-Chip Debug System (DBG) ....................................................................................................192
15.3.1 Comparators A and B ...................................................................................................192
15.3.2 Bus Capture Information and FIFO Operation .............................................................192
15.3.3 Change-of-Flow Information ........................................................................................193
15.3.4 Tag vs. Force Breakpoints and Triggers .......................................................................193
15.3.5 Trigger Modes ..............................................................................................................194
15.3.6 Hardware Breakpoints ..................................................................................................196
15.4 Register Definition ........................................................................................................................196
15.4.1 BDC Registers and Control Bits ...................................................................................196
15.4.1.1 BDC Status and Control Register (BDCSCR) ..............................................197
15.4.1.2 BDC Breakpoint Match Register (BDCBKPT) ............................................198
15.4.2 System Background Debug Force Reset Register (SBDFR) ........................................198
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
14 Freescale Semiconductor
Section Number Title Page
15.4.3 DBG Registers and Control Bits ..................................................................................199
15.4.3.1 Debug Comparator A High Register (DBGCAH) ........................................199
15.4.3.2 Debug Comparator A Low Register (DBGCAL) .........................................199
15.4.3.3 Debug Comparator B High Register (DBGCBH) .........................................199
15.4.3.4 Debug Comparator B Low Register (DBGCBL) ..........................................199
15.4.3.5 Debug FIFO High Register (DBGFH) ..........................................................200
15.4.3.6 Debug FIFO Low Register (DBGFL) ...........................................................200
15.4.3.7 Debug Control Register (DBGC) ..................................................................201
15.4.3.8 Debug Trigger Register (DBGT) ..................................................................202
15.4.3.9 Debug Status Register (DBGS) .....................................................................203
Appendix A
Electrical Characteristics
A.1 Introduction ...................................................................................................................................205
A.2 Absolute Maximum Ratings ..........................................................................................................205
A.3 Thermal Characteristics .................................................................................................................206
A.4 Electrostatic Discharge (ESD) Protection Characteristics ............................................................207
A.5 DC Characteristics .........................................................................................................................207
A.6 Supply Current Characteristics ......................................................................................................211
A.7 Analog Comparator (ACMP) Electricals ......................................................................................211
A.8 Oscillator Characteristics ..............................................................................................................212
A.9 AC Characteristics .........................................................................................................................212
A.9.1 Control Timing ...............................................................................................................212
A.9.2 Timer/PWM (TPM) Module Timing .............................................................................213
A.9.3 SPI Timing ......................................................................................................................214
A.10 FLASH Specifications ...................................................................................................................218
Appendix B
Ordering Information and Mechanical Drawings
B.1 Ordering Information ....................................................................................................................219
B.2 Mechanical Drawings ....................................................................................................................220
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 15
Chapter 1
Introduction
1.1 Overview
The MC9S08RC/RD/RE/RG are members of the low-cost, high-performance HCS08 Family of 8-bit
microcontroller units (MCUs). All MCUs in this family use the enhanced HCS08 core and are available
with a variety of modules, memory sizes, memory types, and package types.
1.2 Features
Features of the MC9S08RC/RD/RE/RG Family of devices are listed here. Please see Table 1-1 for the
features that are available on the different family members.
HCS08 CPU
(Central Processor Unit)
• Object code fully upward-compatible with M68HC05 and M68HC08 Families
• HC08 instruction set with added BGND instruction
• Support for up to 32 interrupt/reset sources
• Power-saving modes: wait plus three stops
On-Chip Memory • On-chip in-circuit programmable FLASH memory with block protection and security
option
• On-chip random-access memory (RAM)
Oscillator (OSC) • Low power oscillator capable of operating from crystal or resonator from 1 to 16 MHz
• 8 MHz internal bus frequency
Analog Comparator
(ACMP1)
• On-chip analog comparator with internal reference (ACMP1)
• Full rail-to-rail supply operation
• Option to compare to a fixed internal bandgap reference voltage
Serial Communications
Interface Module (SCI1)
• Full-duplex, standard non-return-to-zero (NRZ) format
• Double-buffered transmitter and receiver with separate enables
• Programmable 8-bit or 9-bit character length
• Programmable baud rates (13-bit modulo divider)
Serial Peripheral
Interface Module (SPI1)
• Master or slave mode operation
• Full-duplex or single-wire bidirectional option
• Programmable transmit bit rate
• Double-buffered transmit and receive
• Serial clock phase and polarity options
• Slave select output
• Selectable MSB-first or LSB-first shifting
Introduction
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
16 Freescale Semiconductor
1.2.1 Devices in the MC9S08RD/RE/RG Series
Table 1-1 lists the devic es availabl e in the MC9S08RD/R E/RG se ries and summari zes the differences in
functions and configuration among them.
Timer/Pulse-Width
Modulator (TPM1) • 2-channel , 16-bit timer/pulse-width modulat or (TPM1) module that can operate as a
free- running counter, a mod ulo counter, or an up-/down-counter when the TPM is
configured for center-aligned PW M
• Selectable input captur e, output compare, and edge-aligned or center-aligned PWM
capability on each channel
Keyb oar d In terrupt Ports
(KBI1, KBI2) • Providing 12 keyboard interrupts
• Eight with f all ing-edge/l ow-l evel plus four with sel ectable polari ty
• KBI1 inputs can be configured for edge-only sensit ivity or edge-and-level sensi tivity
Carrier Modulator Timer
(CMT) • Dedicated infrared output (IRO) pin
• Drives IRO pin fo r remote control communications
• Can be disconnected from IRO pin and used as out put compare timer
• IRO output pin has high-current si nk capabilit y
Developm en t Support • Background debugging system (see also t he Development Support chapter)
• Breakpoint capability to allow single breakpoint setting during in-circuit debugging (plus
two more breakpoints i n on-chip debug mo dule)
• Debug module containing two comparators and nin e trigger modes. Eig ht deep FIFO
for sto ri ng change-of-flow addresses and even t-only data. Debug mo dule supports
both tag and force breakpoints.
Port Pins • Eight high-current pins (limited by ma ximu m p ackage d issipati on)
• Soft ware selec tabl e pullup s on port s when used as input . Select ion is on an in divid ual
port bi t basi s. Duri ng output mode, pullups are disengaged.
• 39 general-pur pose i nput/output (I/ O) pins, depending on package selection
Package Options • 28-pin plastic dual in-line package (PDIP)
• 28-pin small outl ine integrated circuit (SOI C)
• 32-pin low-profile quad flat package (LQFP)
• 44-pin low-profile quad flat package (LQFP)
• 48-pin quad flat package (QFN)
System Protecti on • Optional computer operating properl y (COP) reset
• Low-v oltage detect ion with reset or interrupt
• Illegal opcode detection with reset
• Illegal address detection with reset (some devices don’t have illegal addresses)
Table 1-1. Devices i n the MC9S08 RD/RE/RG S eries
Device FLASH RAM ACMP(1)
1. Available only in 32-, 44-, and 48-pin LQFP packages.
SCI SPI
9S08RG32/60 32K/60K 2K/2K Yes Yes Yes
9S08RE8/16/32/60 8/16K/32K/60K 1K/1K/2K/2K Yes Yes No
9S08RD8/16/32/60 8/16K/32K/60K 1K/1K/2K/2K No Yes No
Introduction
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 17
1.3 MCU Block Diagram
This block diagram shows the structure of the MC9S08RC/RD/RE/RG MCUs
Figure 1-1. MC9S08RC/RD/RE/RG Block Diagram
Table 1-2 lists the functional versions of the on-chip modules.
PTD3
PTD4/ACMP1–
PTD5/ACMP1+
PTD6/TPM1CH0
PTC1/KBI2P1
PTC0/KBI2P0
VSS
VDD
PTB3
PTB2
PTA7/KBI1P7–
PTB0/TxD1
PTB1/RxD1
PTD2/IRQ
PTD1/RESET
PTD0/BKGD/MS
PTC7/SS1
PTC6/SPSCK1
PTC5/MISO1
PTC4/MOSI1
PTC3/KBI2P3
PTC2/KBI2P2
PORT A
PORT C
PORT D
PORT B
8-BIT KEYBOARD
INTERRUPT MODULE (KBI1)
SERIAL PERIPHERAL
INTERFACE MODULE (SPI1)
USER FLASH
USER RAM
(RC/RD/RE/RG32/60 = 2048 BYTES)
DEBUG
MODULE (DBG)
(RC/RD/RE/RG60 = 63,364 BYTES)
HCS08 CORE
BDC
CPU
NOTES:
1. Port pins are software configurable with pullup device if input port
2. PTA0 does not have a clamp diode to VDD. PTA0 should not be driven above VDD. Also, PTA0 does not pullup to
VDD when internal pullup is enabled.
3. IRQ pin contains software configurable pullup/pulldown device if IRQ enabled (IRQPE = 1)
4. The RESET pin contains integrated pullup device enabled if reset enabled (RSTPE = 1)
5. High current drive
6. Pins PTA[7:4] contain both pullup and pulldown devices. Pulldown enabled when KBI is enabled (KBIPEn = 1) and
rising edge is selected (KBEDGn = 1).
NOTES
NOTES 1, 5
2-CHANNEL TIMER/PWM
MODULE (TPM1)
PTE7–
PORT E
PTB5
PTB4
PTE6
PTB7/TPM1CH1
MODULE (ACMP1)
HCS08 SYSTEM CONTROL
RESETS AND INTERRUPTS
MODES OF OPERATION
POWER MANAGEMENT
VOLTAGE
REGULATOR
RTI
ANALOG COMPARATOR
COP
IRQ LVD
INTERNAL BUS
LOW-POWER OSCILLATOR
INTERFACE MODULE (SCI1)
SERIAL COMMUNICATIONS
7
PTA1/KBI1P1
8
PTE0
NOTE 1
NOTES1, 2, 6
NOTE 1
(RC/RD/RE/RG32 = 32,768 BYTES)
(RC/RD/RE8/16 = 1024 BYTES)
(RC/RD/RE16 = 16,384 BYTES)
XTAL
EXTAL
CARRIER MODULATOR
TIMER MODULE (CMT)
1, 3, 4
4-BIT KEYBOARD
INTERRUPT MODULE (KBI2)
IRO NOTE 5
PTA0/KBI1P0
(RC/RD/RE8 = 8192 BYTES)
Introduction
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
18 Freescale Semiconductor
1.4 System Clock Distribution
Figure 1-2. System Clock Distribution Diagram
Table 1-2 shows a simplified clock connection diagram for the MCU. The CPU operates at the input
frequency of the oscillator. The bus clock frequency is half of the oscillator frequency and is used by all of
the internal circuits with the exception of the CPU and RTI. The RTI can use either the oscillator input or
the internal RTI oscillator as its clock source.
Table 1-2. Block Versions
Module Version
Analog Comparator (ACMP) 1
Carrier Modulator Transmitter (CMT) 1
Keyboard Interrupt (KBI) 1
Serial Communications Interface (SCI) 1
Serial Peripheral Interface (SPI) 3
Timer Pulse-Width Modulator (TPM) 1
Central Processing Unit (CPU) 2
Debug Module (DBG) 1
FLASH 1
System Control 2
TPM CMT SCI SPI
BDC
CPU ACMP RAM FLASH
OSC
OSCOUT* ÷2
SYSTEM
LOGIC
BUSCLK
FLASH has frequency
requirements for program
and erase operation.
See Appendix A.
CONTROL
RTI
RTI
OSC
RTICLKS
* OSCOUT is the alternate BDC clock source for the MC9S08RC/RD/RE/RG.
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 19
Chapter 2
Pins and Connections
2.1 Introduction
This section describes signals that connect to package pins. It includes a pinout diagram, a table of signal
properties, and detailed discussion of signals.
2.2 Device Pin Assignment
Figure 2-1. MC9S08RC/RD/RE/RG in 44-Pin LQFP Package
44
34
43
42
41
40
39
38
37
36
35
1
2
3
4
5
6
7
8
9
10
11
13
14
15
16
17
18
19
20
21
22
33
32
31
30
29
28
27
26
25
24
12
23
PTB0/TxD1
PTB5
PTB6
PTB7/TPM1CH1
PTB1/RxD1
PTB2
PTB3
PTB4
VDD
VSS
IRO
PTE3
PTE2
PTE1
PTE0
PTC3/KBI2P3
PTC2/KBI2P2
PTC1/KBI2P1
PTC0/KBI2P0
PTC4/MOSI1
PTC5/MISO1
PTC6/SPSCK1
XTAL
EXTAL
PTD4/ACMP1–
PTD5/ACMP1+
PTD6/TPM1CH0
PTD0/BKGD/MS
PTD1/RESET
PTC7/SS1
PTD2/IRQ
PTD3
PTA3/KBI1P3
PTE4
PTE7
PTA7/KBI1P7
PTA6/KBI1P6
PTA5/KBI1P5
PTA4/KBI1P4
PTA0/KBI1P0
PTE5
PTE6
PTA2/KBI1P2
PTA1/KBI1P1
Pins and Connections
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
20 Freescale Semiconductor
Figure 2-2. MC9S08RC/RD/RE/RG in 32-Pin LQFP Package
Figure 2-3. MC9S08RC/RD/RE/RG in 28-Pin SOIC Package and 28-Pin PDIP Package
PTB7/TPM1CH1
PTA0/KBI1P0
PTB6
IRO
VSS
VDD
PTB2
PTB1/RxD1
PTB0/TxD1 PTD6/TPM1CH0
PTD5/ACMP1+
PTD4/ACMP1–
EXTAL
XTAL
PTD2/IRQ
PTD1/RESET
PTD0/BKGD/MS
PTA7/KBI1P7
PTA6/KBI1P6
PTA5/KBI1P5
PTA4/KBI1P4
PTA3/KBI1P3
PTA2/KBI1P2
PTA1/KBI1P1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
16
PTC7/SS1
PTC0/KBI2P0
PTC1/KBI2P1
PTC2/KBI2P2
PTC3/KBI2P3
PTC4/MISO1
PTC5/MISO1
PTC6/SPSCK1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
PTB2
PTC3/KBI2P3
XTAL
EXTAL
PTD6/TPM1CH0
PTA0/KBI1P0
PTA1/KBI1P1
PTA2/KBI1P2
PTA3/KBI1P3
PTA4/KBI1P4
PTC6/SPSCK1
PTC7/SS1
PTC4/MOSI1
PTC5/MISO1
PTA6/KBI1P6
PTA5/KBI1P5
PTD0/BKGD/MS
PTD1/RESET
PTA7/KBI1P7
PTB0/TxD1
PTB1/RxD1
VDD
VSS
IRO
PTB7/TPM1CH1
PTC0/KBI2P0
PTC1/KBI2P1
PTC2/KBI2P2
Pins and Connections
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 21
Figure 2-4. MC9S08RC/RD/RE/RG in 48-Pin QFN Package
2.3 Recommended System Connections
Figure 2-5 shows pin connections that are common to almost all MC9S08RC/RD/RE/RG application
systems. A more detailed discussion of system connections follows.
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
36
35
34
33
32
31
30
29
28
25
1
27
26
PTB0/TxD1
PTB1/RxD1
PTB2
PTB3
PTB4
VDD
IRQ
PTB5
PTB6
PTB7/TPM1CH1
VSS
NC
PTA0/KBI1P0
PTD6/TPM1CH0
PTD5/ACMP1+
PTD4/ACMP1–
EXTAL
XTAL
PTD2/IRQ
PTD1/RESET
PTD0/BKGD/MS
PTC7/SS1
PTD3
NC
PTA7/KBI1P7
PTA6/KBI1P6
PTA5/KBI1P5
PTA4/KBI1P4
PTE7
PTE6
PTE4
PTA3/KBI1P3
PTA2/KBI1P2
PTA1/KBI1P1
PTE5
NCPTC0/KBI2P0
PTC1/KBI2P1
PTC2/KBI2P2
PTC3/KBI2P3
PTE0
PTE1
PTE3
PTC4/MOSI1
PTC5/MISO1
PTC6/SPSCK1
PTE2
NC
48
47
46
45
44
43
42
41
40
39
38
37
Pins and Connections
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
22 Freescale Semiconductor
Figure 2-5. Basic System Connections
VDD
VSS
XTAL
EXTAL
BKGD/MS
RESET
OPTIONAL
MANUAL
RESET
PORT
A
VDD
1
BACKGROUND HEADER
C1
C2 X1
RF
CBY
0.1 µF
CBLK
10 µF
+
3 V
+
SYSTEM
POWER
I/O AND
PERIPHERAL
INTERFACE TO
SYSTEM
APPLICATION
PTA0/KBI1P0
PTA1/KBI1P1
PTA2/KBI1P2
PTA3/KBI1P3
PTA4/KBI1P4
PTA5/KBI1P5
PTA6/KBI1P6
PTA7/KBI1P7
VDD
PORT
B
PTB0/TxD1
PTB1/RxD1
PTB2
PTB3
PTB4
PTB5
PTB6
PTB7/TPM1CH1
PORT
C
PTC0/KBI2P0
PTC1/KBI2P1
PTC2/KBI2P2
PTC3/KBI2P3
PTC4/MOSI1
PTC5/MISO1
PTC6/SPSCK1
PTC7/SS1
PORT
D
PTD0/BKGD/MS
PTD1/RESET
PTD2/IRQ
PTD3
PTD4/ACMP1–
PTD5/ACMP1+
PTD6/TPM1CH0
PORT
E
PTE0
PTE1
PTE2
PTE3
PTE4
PTE5
PTE6
PTE7
NOTES:
1. BKGD/MS is the
same pin as PTD0.
2. RESET is the
same pin as PTD1.
NOTE 1
MC9S08RC/RD/RE/RG
NOTE 2
IRO
Pins and Connections
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 23
2.3.1 Power
VDD and VSS are the primary power supply pins for the MCU. This voltage source supplies power to all
I/O buffer circuitry and to an internal voltage regulator. The internal voltage regulator provides a regulated
lower-voltage source to the CPU and other internal circuitry of the MCU.
Typically, application systems have two separate capacitors across the power pins. In this case, there
should be a bulk electrolytic capacitor, such as a 10-µF tantalum capacitor, to provide bulk charge storage
for the overall system and a 0.1-µF ceramic bypass capacitor located as near to the MCU power pins as
practical to suppress high-frequency noise.
2.3.2 Oscillator
The oscillator in the MC9S08RC/RD/RE/RG is a traditional Pierce oscillator that can accommodate a
crystal or ceramic resonator in the range of 1 MHz to 16 MHz.
Refer to Figure 2-5 for the following discussion. RFshould be a low-inductance resistor such as a carbon
composition resistor. Wire-wound resistors, and some metal film resistors, have too much inductance. C1
and C2 normally should be high-quality ceramic capacitors specifically designed for high-frequency
applications.
RFis used to provide a bias path to keep the EXTAL input in its linear range during crystal startup and its
value is not generally critical. Typical systems use 1 MΩ. Higher values are sensitive to humidity and lower
values reduce gain and (in extreme cases) could prevent startup.
C1 and C2 are typically in the 5-pF to 25-pF range and are chosen to match the requirements of a specific
crystal or resonator. Be sure to take into account printed circuit board (PCB) capacitance and MCU pin
capacitance when sizing C1 and C2. The crystal manufacturer typically specifies a load capacitance that
is the series combination of C1 and C2, which are usually the same size. As a first-order approximation,
use 5 pF as an estimate of combined pin and PCB capacitance for each oscillator pin (EXTAL and XTAL).
2.3.3 PTD1/RESET
The external pin reset function is shared with an output-only port function on the PTD1/RESET pin. The
reset function is enabled when RSTPE in SOPT is set. RSTPE is set following any reset of the MCU and
must be cleared in order to use this pin as an output-only port.
Whenever any reset is initiated (whether from an external signal or from an internal system), the reset pin
is driven low for about 34 cycles of fSelf_reset, released, and sampled again about 38 cycles of fSelf_reset
later. If reset was caused by an internal source such as low-voltage reset or watchdog timeout, the circuitry
expects the reset pin sample to return a logic 1. If the pin is still low at this sample point, the reset is
assumed to be from an external source. The reset circuitry decodes the cause of reset and records it by
setting a corresponding bit in the system control reset status register (SRS).
Never connect any significant capacitance to the reset pin because that would interfere with the circuit and
sequence that detects the source of reset. If an external capacitance prevents the reset pin from rising to a
valid logic 1 before the reset sample point, all resets will appear to be external resets.
Pins and Connections
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
24 Freescale Semiconductor
2.3.4 Background/Mode Select (PTD0/BKGD/MS)
The background/mode select function is shared with an output-only port function on the PTD0/BKDG/MS
pin. While in reset, the pin functions as a mode select pin. Immediately after reset rises, the pin functions
as the background pin and can be used for background debug communication. While functioning as a
background/mode select pin, this pin has an internal pullup device enabled. To use as an output-only port,
BKGDPE in SOPT must be cleared.
If nothing is connected to this pin, the MCU will enter normal operating mode at the rising edge of reset.
If a debug system is connected to the 6-pin standard background debug header, it can hold BKGD/MS low
during the rising edge of reset, which forces the MCU to active background mode.
The BKGD pin is used primarily for background debug controller (BDC) communications using a custom
protocol that uses 16 clock cycles of the target MCU’s BDC clock per bit time. The target MCU’s BDC
clock could be as fast as the bus clock rate, so there should never be any significant capacitance connected
to the BKGD/MS pin that could interfere with background serial communications.
Although the BKGD pin is a pseudo open-drain pin, the background debug communication protocol
provides brief, actively driven, high speedup pulses to ensure fast rise times. Small capacitances from
cables and the absolute value of the internal pullup device play almost no role in determining rise and fall
times on the BKGD pin.
2.3.5 IRO Pin Description
The IRO pin is the output of the CMT. See the Carrier Modulator Timer (CMT) Module Chapter for a
detailed description of this pin function.
2.3.6 General-Purpose I/O and Peripheral Ports
The remaining pins are shared among general-purpose I/O and on-chip peripheral functions such as timers
and serial I/O systems. (Not all pins are available in all packages. See Table 2-2.) Immediately after reset,
all 37 of these pins are configured as high-impedance general-purpose inputs with internal pullup devices
disabled.
NOTE
To avoid extra current drain from floating input pins, the reset initialization
routine in the application program should either enable on-chip pullup
devices or change the direction of unused pins to outputs so the pins do not
float.
For information about controlling these pins as general-purpose I/O pins, see the Chapter 6, “Parallel
Input/Output." For information about how and when on-chip peripheral systems use these pins, refer to the
appropriate chapter from Table 2-1.
Pins and Connections
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 25
When an on-chip peripheral system is controlling a pin, data direction control bits still determine what is
read from port data registers even though the peripheral module controls the pin direction by controlling
the enable for the pin’s output buffer. See the Chapter 6, “Parallel Input/Output,” for more details.
Pullup enable bits for each input pin control whether on-chip pullup devices are enabled whenever the pin
is acting as an input even if it is being controlled by an on-chip peripheral module. When the PTA7–PTA4
pins are controlled by the KBI module and are configured for rising-edge/high-level sensitivity, the pullup
enable control bits enable pulldown devices rather than pullup devices. Similarly, when PTD2 is
configured as the IRQ input and is set to detect rising edges, the pullup enable control bit enables a
pulldown device rather than a pullup device.
2.3.7 Signal Properties Summary
Table 2-2 summarizes I/O pin characteristics. These characteristics are determined by the way the
common pin interfaces are hardwired to internal circuits.
Table 2-1. Pin Sharing References
Port Pins Alternate
Function Reference(1)
1. See this chapter for information about modules that share these pins.
PTA7–PTA0 KBI1P7–KBI1P0 Chapter 9, “Keyboard Interrupt (S08KBIV1)”
PTB7 TPM1CH1 Chapter 10, “Timer/PWM Module (S08TPMV1)”
PTB6–PTB2 — Chapter 6, “Parallel Input/Output”
PTB1
PTB0
RxD1
TxD1
Chapter 11, “Serial Communications Interface (S08SCIV1)”
PTC7
PTC6
PTC5
PTC4
SS1
SPSCK1
MISO1
MOSI1
Chapter 13, “Serial Peripheral Interface (S08SPIV3)”
PTC3–PTC0 KBI2P3–KBI2P0 Chapter 9, “Keyboard Interrupt (S08KBIV1)”
PTD6 TPM1CH0 Chapter 10, “Timer/PWM Module (S08TPMV1)”
PTD5
PTD4
ACMP1+
ACMP1–
Chapter 14, “Analog Comparator (S08ACMPV1)”
PTD2 IRQ Chapter 5, “Resets, Interrupts, and System Configuration”
PTD1 RESET
PTD0 BKGD/MS
PTE7–PTE0 — Chapter 6, “Parallel Input/Output”
Pins and Connections
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
26 Freescale Semiconductor
Table 2-2. Signal Properties
Pin
Name Dir(1) High Current
Pin Pullup(2) Comments(3)
VDD ——
VSS ——
XTAL O — — Crystal oscillator output
EXTAL I — — Crystal oscillator input
IRO O Y — Infrared output
PTA0/KBI1P0 I N SWC PTA0 does not have a clamp diode to VDD. PTA0 should not be
driven above VDD.
PTA1/KBI1P1 I/O N SWC
PTA2/KBI1P2 I/O N SWC
PTA3/KBI1P3 I/O N SWC
PTA4/KBI1P4 I/O N SWC
PTA5/KBI1P5 I/O N SWC
PTA6/KBI1P6 I/O N SWC
PTA7/KBI1P7 I/O N SWC
PTB0/TxD1 I/O Y SWC
PTB1/RxD1 I/O Y SWC
PTB2 I/O Y SWC
PTB3 I/O Y SWC Available only in 44- and 48-pin packages
PTB4 I/O Y SWC Available only in 44- and 48-pin packages
PTB5 I/O Y SWC Available only in 44- and 48-pin packages
PTB6 I/O Y SWC Available only in 32-, 44-, and 48-pin packagess
PTB7/TPM1CH1 I/O Y SWC
PTC0/KBI2P0 I/O N SWC
PTC1/KBI2P1 I/O N SWC
PTC2/KBI2P2 I/O N SWC
PTC3/KBI2P3 I/O N SWC
PTC4/MOSI1 I/O N SWC
PTC5/MISO1 I/O N SWC
PTC6/SPSCK1 I/O N SWC
PTC7/SS1 I/O N SWC
PTD0/BKGD/MS I/O N SWC(4) Output-only when configured as PTD0 pin. Pullup enabled.
PTD1/RESET I/O N SWC(3) Output-only when configured as PTD1 pin.
Pins and Connections
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 27
PTD2/IRQ I/O N SWC(5) Available only in 32-, 44-, and 48-pin packagess
PTD3 I/O N SWC Available only in 44- and 48-pin packages
PTD4/ACMP1– I/O N SWC Available only in 32-, 44-, and 48-pin packagess
PTD5/ACMP1+ I/O N SWC Available only in 32-, 44-, and 48-pin packagess
PTD6/TPM1CH0 I/O N SWC
PTE0 I/O N SWC Available only in 44- and 48-pin packages
PTE1 I/O N SWC Available only in 44- and 48-pin packages
PTE2 I/O N SWC Available only in 44- and 48-pin packages
PTE3 I/O N SWC Available only in 44- and 48-pin packages
PTE4 I/O N SWC Available only in 44- and 48-pin packages
PTE5 I/O N SWC Available only in 44- and 48-pin packages
PTE6 I/O N SWC Available only in 44- and 48-pin packages
PTE7 I/O N SWC Available only in 44- and 48-pin packages
1. Unless otherwise indicated, all digital inputs have input hysteresis.
2. SWC is software-controlled pullup resistor, the register is associated with the respective port.
3. Not all general-purpose I/O pins are available on all packages. To avoid extra current drain from floating input pins, the user’s
reset initialization routine in the application program should either enable on-chip pullup devices or change the direction of
unconnected pins to outputs so the pins do not float.
4. When these pins are configured as RESET or BKGD/MS pullup device is enabled.
5. When configured for the IRQ function, this pin will have a pullup device enabled when the IRQ is set for falling edge detection
and a pulldown device enabled when the IRQ is set for rising edge detection.
Table 2-2. Signal Properties (continued)
Pin
Name Dir(1) High Current
Pin Pullup(2) Comments(3)
Pins and Connections
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
28 Freescale Semiconductor
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 29
Chapter 3
Modes of Operation
3.1 Introduction
The operating modes of the MC9S08RC/RD/RE/RG are described in this section. Entry into each mode,
exit from each mode, and functionality while in each of the modes are described.
3.2 Features
• Active background mode for code development
• Wait mode:
— CPU shuts down to conserve power
— System clocks running
— Full voltage regulation maintained
• Stop modes:
— System clocks stopped; voltage regulator in standby
— Stop1 — Full power down of internal circuits for maximum power savings
— Stop2 — Partial power down of internal circuits, RAM remains operational
— Stop3 — All internal circuits powered for fast recovery
3.3 Run Mode
This is the normal operating mode for the MC9S08RC/RD/RE/RG. This mode is selected when the
BKGD/MS pin is high at the rising edge of reset. In this mode, the CPU executes code from internal
memory with execution beginning at the address fetched from memory at $FFFE:$FFFF after reset.
3.4 Active Background Mode
The active background mode functions are managed through the background debug controller (BDC) in
the HCS08 core. The BDC, together with the on-chip debug module (DBG), provide the means for
analyzing MCU operation during software development.
Active background mode is entered in any of five ways:
• When the BKGD/MS pin is low at the rising edge of reset
• When a BACKGROUND command is received through the BKGD pin
• When a BGND instruction is executed
• When encountering a BDC breakpoint
• When encountering a DBG breakpoint
Modes of Operation
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
30 Freescale Semiconductor
After active background mode is entered, the CPU is held in a suspended state waiting for serial
background commands rather than executing instructions from the user’s application program.
Background commands are of two types:
• Non-intrusive commands, defined as commands that can be issued while the user program is
running. Non-intrusive commands can be issued through the BKGD pin while the MCU is in run
mode; non-intrusive commands can also be executed when the MCU is in the active background
mode. Non-intrusive commands include:
— Memory access commands
— Memory-access-with-status commands
— BDC register access commands
— BACKGROUND command
• Active background commands, which can only be executed while the MCU is in active background
mode, include commands to:
— Read or write CPU registers
— Trace one user program instruction at a time
— Leave active background mode to return to the user’s application program (GO)
The active background mode is used to program a bootloader or user application program into the FLASH
program memory before the MCU is operated in run mode for the first time. When the
MC9S08RC/RD/RE/RG is shipped from the Freescale Semiconductor factory, the FLASH program
memory is usually erased so there is no program that could be executed in run mode until the FLASH
memory is initially programmed. The active background mode can also be used to erase and reprogram
the FLASH memory after it has been previously programmed.
For additional information about the active background mode, refer to the Development Support chapter.
3.5 Wait Mode
Wait mode is entered by executing a WAIT instruction. Upon execution of the WAIT instruction, the CPU
enters a low-power state in which it is not clocked. The I bit in CCR is cleared when the CPU enters the
wait mode, enabling interrupts. When an interrupt request occurs, the CPU exits the wait mode and
resumes processing, beginning with the stacking operations leading to the interrupt service routine.
Only the BACKGROUND command and memory-access-with-status commands are available when the
MCU is in wait mode. The memory-access-with-status commands do not allow memory access, but they
report an error indicating that the MCU is in either stop or wait mode. The BACKGROUND command can
be used to wake the MCU from wait mode and enter active background mode.
Modes of Operation
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 31
3.6 Stop Modes
One of three stop modes is entered upon execution of a STOP instruction when the STOPE bit in the
system option register is set. In all stop modes, all internal clocks are halted. If the STOPE bit is not set
when the CPU executes a STOP instruction, the MCU will not enter any of the stop modes and an illegal
opcode reset is forced. The stop modes are selected by setting the appropriate bits in SPMSC2.
Table 3-1 summarizes the behavior of the MCU in each of the stop modes.
3.6.1 Stop1 Mode
Stop1 mode provides the lowest possible standby power consumption by causing the internal circuitry of
the MCU to be powered down. To enter stop1, the user must execute a STOP instruction with the PDC bit
in SPMSC2 set and the PPDC bit clear. Stop1 can be entered only if the LVD reset is disabled
(LVDRE = 0).
When the MCU is in stop1 mode, all internal circuits that are powered from the voltage regulator are turned
off. The voltage regulator is in a low-power standby state, as are the OSC and ACMP.
Exit from stop1 is done by asserting any of the wakeup pins on the MCU: RESET, IRQ, or KBI1, which
have been enabled. IRQ and KBI pins are always active-low when used as wakeup pins in stop1 regardless
of how they were configured before entering stop1.
Upon wakeup from stop1 mode, the MCU will start up as from a power-on reset (POR). The CPU will take
the reset vector.
3.6.2 Stop2 Mode
Stop2 mode provides very low standby power consumption and maintains the contents of RAM and the
current state of all of the I/O pins. To select entry into stop2 upon execution of a STOP instruction, the user
must execute a STOP instruction with the PPDC and PDC bits in SPMSC2 set. Stop2 can be entered only
if LVDRE = 0.
Before entering stop2 mode, the user must save the contents of the I/O port registers, as well as any other
memory-mapped registers that they want to restore after exit of stop2, to locations in RAM. Upon exit from
stop2, these values can be restored by user software.
When the MCU is in stop2 mode, all internal circuits that are powered from the voltage regulator are turned
off, except for the RAM. The voltage regulator is in a low-power standby state, as is the ACMP. Upon entry
Table 3-1. Stop Mode Behavior
Mode PDC PPDC
CPU, Digital
Peripherals,
FLASH
RAM OSC ACMP Regulator I/O Pins RTI
Stop1 1 0 Off Off Off Standby Standby Reset Off
Stop2 1 1 Off Standby Off Standby Standby States
held
Optionally on
Stop3 0 Don’t
care
Standby Standby Off Standby Standby States
held
Optionally on
Modes of Operation
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
32 Freescale Semiconductor
into stop2, the states of the I/O pins are latched. The states are held while in stop2 mode and after exiting
stop2 mode until a 1 is written to PPDACK in SPMSC2.
Exit from stop2 is done by asserting any of the wakeup pins: RESET, IRQ, or KBI1 that have been enabled,
or through the real-time interrupt. IRQ and KBI1 pins are always active-low when used as wakeup pins in
stop2 regardless of how they were configured before entering stop2. (KBI2 will not wake the MCU from
stop2.)
Upon wakeup from stop2 mode, the MCU will start up as from a power-on reset (POR) except pin states
remain latched. The CPU will take the reset vector. The system and all peripherals will be in their default
reset states and must be initialized.
After waking up from stop2, the PPDF bit in SPMSC2 is set. This flag may be used to direct user code to
go to a stop2 recovery routine. PPDF remains set and the I/O pin states remain latched until a 1 is written
to PPDACK in SPMSC2.
For pins that were configured as general-purpose I/O, the user must copy the contents of the I/O port
registers, which have been saved in RAM, back to the port registers before writing to the PPDACK bit. If
the port registers are not restored from RAM before writing to PPDACK, then the register bits will be in
their reset states when the I/O pin latches are opened and the I/O pins will switch to their reset states.
For pins that were configured as peripheral I/O, the user must reconfigure the peripheral module that
interfaces to the pin before writing to the PPDACK bit. If the peripheral module is not enabled before
writing to PPDACK, the pins will be controlled by their associated port control registers when the I/O
latches are opened.
3.6.3 Stop3 Mode
Upon entering stop3 mode, all of the clocks in the MCU, including the oscillator itself, are halted. The
OSC is turned off, the ACMP is disabled, and the voltage regulator is put in standby. The states of all of
the internal registers and logic, as well as the RAM content, are maintained. The I/O pin states are not
latched at the pin as in stop2. Instead they are maintained by virtue of the states of the internal logic driving
the pins being maintained.
Exit from stop3 is done by asserting RESET, any asynchronous interrupt pin that has been enabled, or
through the real-time interrupt. The asynchronous interrupt pins are the IRQ or KBI1 and KBI2 pins.
If stop3 is exited by means of the RESET pin, then the MCU will be reset and operation will resume after
taking the reset vector. Exit by means of an asynchronous interrupt or the real-time interrupt will result in
the MCU taking the appropriate interrupt vector.
A separate self-clocked source (≈1 kHz) for the real-time interrupt allows a wakeup from stop2 or stop3
mode with no external components. When RTIS2:RTIS1:RTIS0 = 0:0:0, the real-time interrupt function
and this 1-kHz source are disabled. Power consumption is lower when the 1-kHz source is disabled, but in
that case the real-time interrupt cannot wake the MCU from stop.
Modes of Operation
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 33
3.6.4 Active BDM Enabled in Stop Mode
Entry into the active background mode from run mode is enabled if the ENBDM bit in BDCSCR is set.
This register is described in the Development Support chapter of this data sheet. If ENBDM is set when
the CPU executes a STOP instruction, the system clocks to the background debug logic remain active when
the MCU enters stop mode so background debug communication is still possible. In addition, the voltage
regulator does not enter its low-power standby state but maintains full internal regulation. The MCU
cannot enter either stop1 mode or stop2 mode if ENBDM is set.
Most background commands are not available in stop mode. The memory-access-with-status commands
do not allow memory access, but they report an error indicating that the MCU is in either stop or wait
mode. The BACKGROUND command can be used to wake the MCU from stop and enter active
background mode if the ENBDM bit is set. After active background mode is entered, all background
commands are available. Table 3-2 summarizes the behavior of the MCU in stop when entry into the active
background mode is enabled.
3.6.5 LVD Reset Enabled
The LVD system is capable of generating either an interrupt or a reset when the supply voltage drops below
the LVD voltage. If the LVD reset is enabled in stop by setting the LVDRE bit in SPMSC1 when the CPU
executes a STOP instruction, then the voltage regulator remains active during stop mode. If the user
attempts to enter either stop1 or stop2 with the LVD reset enabled (LVDRE = 1) the MCU will instead
enter stop3. Table 3-3 summarizes the behavior of the MCU in stop when LVD reset is enabled.
3.6.6 On-Chip Peripheral Modules in Stop Mode
When the MCU enters any stop mode, system clocks to the internal peripheral modules are stopped. Even
in the exception case (ENBDM = 1), where clocks are kept alive to the background debug logic, clocks to
the peripheral systems are halted to reduce power consumption.
Table 3-2. BDM Enabled Stop Mode Behavior
Mode PDC PPDC
CPU, Digital
Peripherals,
FLASH
RAM OSC ACMP Regulator I/O Pins RTI
Stop3 Don’t
care
Don’t
care
Standby Standby On Standby On States
held
Optionally on
Table 3-3. LVD Enabled Stop Mode Behavior
Mode PDC PPDC
CPU, Digital
Peripherals,
FLASH
RAM OSC ACMP Regulator I/O Pins RTI
Stop3 Don’t
care
Don’t
care
Standby Standby On Standby On States
held
Optionally on
Modes of Operation
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
34 Freescale Semiconductor
I/O Pins
• All I/O pin states remain unchanged when the MCU enters stop3 mode.
• If the MCU is configured to go into stop2 mode, all I/O pin states are latched before entering stop.
Pin states remain latched until the PPDACK bit is written.
• If the MCU is configured to go into stop1 mode, all I/O pins are forced to their default reset state
upon entry into stop.
Memory
• All RAM and register contents are preserved while the MCU is in stop3 mode.
• All registers will be reset upon wakeup from stop2, but the contents of RAM are preserved. The
user may save any memory-mapped register data into RAM before entering stop2 and restore the
data upon exit from stop2.
• All registers will be reset upon wakeup from stop1 and the contents of RAM are not preserved. The
MCU must be initialized as upon reset. The contents of the FLASH memory are non-volatile and
are preserved in any of the stop modes.
OSC — In any of the stop modes, the OSC stops running.
TPM — When the MCU enters stop mode, the clock to the TPM module stops. The modules halt
operation. If the MCU is configured to go into stop2 or stop1 mode, the TPM module will be reset upon
wakeup from stop and must be reinitialized.
ACMP — When the MCU enters any stop mode, the ACMP will enter a low-power standby state.No
compare operation will occur while in stop. If the MCU is configured to go into stop2 or stop1 mode, the
ACMP will be reset upon wakeup from stop and must be reinitialized.
KBI — During stop3, the KBI pins that are enabled continue to function as interrupt sources. During stop1
or stop2, enabled KBI1 pins function as wakeup inputs. When functioning as a wakeup, a KBI pin is
always active low regardless of how it was configured before entering stop1 or stop2.
SCI — When the MCU enters stop mode, the clock to the SCI module stops. The module halts operation.
If the MCU is configured to go into stop2 or stop1 mode, the SCI module will be reset upon wakeup from
stop and must be reinitialized.
SPI — When the MCU enters stop mode, the clock to the SPI module stops. The module halts operation.
If the MCU is configured to go into stop2 or stop1 mode, the SPI module will be reset upon wakeup from
stop and must be reinitialized.
CMT — When the MCU enters stop mode, the clock to the CMT module stops. The module halts
operation. If the MCU is configured to go into stop2 or stop1 mode, the CMT module will be reset upon
wakeup from stop and must be reinitialized.
Voltage Regulator — The voltage regulator enters a low-power standby state when the MCU enters any
of the stop modes unless the LVD reset function is enabled or BDM is enabled.
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 35
Chapter 4
Memory
4.1 MC9S08RC/RD/RE/RG Memory Map
As shown in Figure 4-1, on-chip memory in the MC9S08RC/RD/RE/RG series of MCUs consists of
RAM, FLASH program memory for nonvolatile data storage, and I/O and control/status registers. The
registers are divided into three groups:
• Direct-page registers ($0000 through $0045 for 32K and 60K parts, and $0000 through $003F for
16K and 8K parts)
• High-page registers ($1800 through $182B)
• Nonvolatile registers ($FFB0 through $FFBF)
Memory
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
36 Freescale Semiconductor
Figure 4-1. MC9S08RC/RD/RE/RG Memory Map
4.1.1 Reset and Interrupt Vector Assignments
Figure 4-2 shows address assignments for reset and interrupt vectors. The vector names shown in this table
are the labels used in the Freescale-provided equate file for the MC9S08RC/RD/RE/RG. For more details
about resets, interrupts, interrupt priority, and local interrupt mask controls, refer to the Chapter 5, “Resets,
Interrupts, and System Configuration."
DIRECT PAGE REGISTERS
RAM
FLASH
HIGH PAGE REGISTERS
FLASH
2048 BYTES
4026 BYTES
59348 BYTES
$0000
$0045
$0046
$0845
$1800
$17FF
$182B
$182C
$FFFF
$0846
$0000
$003F
$0040
$043F
$1800
$17FF
$182B
$182C
$FFFF
$0440
$C000
$BFFF
MC9S08RC/RD/RE/RG60 MC9S08RC/RD/RE16
$0000
$0045
$0046
$0845
$1800
$17FF
$182B
$0846
$8000
MC9S08RC/RD/RE/RG32
$182C
DIRECT PAGE REGISTERS
RAM
UNIMPLEMENTED
HIGH PAGE REGISTERS
FLASH
2048 BYTES
4026 BYTES
32768 BYTES
DIRECT PAGE REGISTERS
RAM
UNIMPLEMENTED
HIGH PAGE REGISTERS
FLASH
1024 BYTES(1)
5056 BYTES
16384 BYTES
UNIMPLEMENTED
26580 BYTES
UNIMPLEMENTED
42964 BYTES
$0000
$003F
$0040
$043F
$1800
$17FF
$182B
$182C
$FFFF
$0440
$E000
$DFFF
MC9S08RC/RD/RE8
DIRECT PAGE REGISTERS
RAM
UNIMPLEMENTED
HIGH PAGE REGISTERS
FLASH
1024 BYTES(1)
5056 BYTES
8192 BYTES
UNIMPLEMENTED
51156 BYTES
Memory
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 37
Figure 4-2. Reset and Interrupt Vectors
Vector
Number
Address
(High/Low) Vector Vector Name
16
through
31
$FFC0:FFC1
$FFDE:FFDF
Unused Vector Space
(available for user program)
15 $FFE0:FFE1 SPI(1)
1. The SPI module is not included on the MC9S08RC/RD/RE devices. This vector location is unused for those devices.
Vspi1
14 $FFE2:FFE3 RTI Vrti
13 $FFE4:FFE5 KBI2 Vkeyboard2
12 $FFE6:FFE7 KBI1 Vkeyboard1
11 $FFE8:FFE9 ACMP(2)
2. The analog comparator (ACMP) module is not included on the MC9S08RD devices. This vector location is unused for
those devices.
Vacmp1
10 $FFEA:FFEB CMT Vcmt
9 $FFEC:FFED SCI Transmit(3)
3. The SCI module is not included on the MC9S08RC devices. This vector location is unused for those devices.
Vsci1tx
8 $FFEE:FFEF SCI Receive(3) Vsci1rx
7 $FFF0:FFF1 SCI Error(3) Vsci1err
6 $FFF2:FFF3 TPM Overflow Vtpm1ovf
5 $FFF4:FFF5 TPM Channel 1 Vtpm1ch1
4 $FFF6:FFF7 TPM Channel 0 Vtpm1ch0
3 $FFF8:FFF9 IRQ Virq
2 $FFFA:FFFB Low Voltage Detect Vlvd
1 $FFFC:FFFD SWI Vswi
0 $FFFE:FFFF Reset Vreset
Memory
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
38 Freescale Semiconductor
4.2 Register Addresses and Bit Assignments
The registers in the MC9S08RC/RD/RE/RG are divided into these three groups:
• Direct-page registers are located within the first 256 locations in the memory map, so they are
accessible with efficient direct addressing mode instructions.
• High-page registers are used much less often, so they are located above $1800 in the memory map.
This leaves more room in the direct page for more frequently used registers and variables.
• The nonvolatile register area consists of a block of 16 locations in FLASH memory at
$FFB0–$FFBF.
Nonvolatile register locations include:
— Three values that are loaded into working registers at reset
— An 8-byte backdoor comparison key that optionally allows a user to gain controlled access to
secure memory
Because the nonvolatile register locations are FLASH memory, they must be erased and
programmed like other FLASH memory locations.
Direct-page registers can be accessed with efficient direct addressing mode instructions. Bit manipulation
instructions can be used to access any bit in any direct-page register. Table 4-1 is a summary of all
user-accessible direct-page registers and control bits.
The direct page registers in Table 4-1 can use the more efficient direct addressing mode, which requires
only the lower byte of the address. Because of this, the lower byte of the address in column one is shown
in bold text. In Table 4-2 and Table 4-3, the whole address in column one is shown in bold. In Table 4-1,
Table 4-2, and Table 4-3, the register names in column two are shown in bold to set them apart from the
bit names to the right. Cells that are not associated with named bits are shaded. A shaded cell with a 0
indicates this unused bit always reads as a 0. Shaded cells with dashes indicate unused or reserved bit
locations that could read as 1s or 0s.
Memory
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 39
Table 4-1. Direct-Page Register Summary
Address Register Name Bit 7 654321Bit 0
$0000 PTAD PTAD7 PTAD6 PTAD5 PTAD4 PTAD3 PTAD2 PTAD1 PTAD0
$0001 PTAPE PTAPE7 PTAPE6 PTAPE5 PTAPE4 PTAPE3 PTAPE2 PTAPE1 PTAPE0
$0002 Reserved — — — — — — — —
$0003 PTADD PTADD7 PTADD6 PTADD5 PTADD4 PTADD3 PTADD2 PTADD1 PTADD0
$0004 PTBD PTBD7 PTBD6 PTBD5 PTBD4 PTBD3 PTBD2 PTBD1 PTBD0
$0005 PTBPE PTBPE7 PTBPE6 PTBPE5 PTBPE4 PTBPE3 PTBPE2 PTBPE1 PTBPE0
$0006 Reserved — — — — — — — —
$0007 PTBDD PTBDD7 PTBDD6 PTBDD5 PTBDD4 PTBDD3 PTBDD2 PTBDD1 PTBDD0
$0008 PTCD PTCD7 PTCD6 PTCD5 PTCD4 PTCD3 PTCD2 PTCD1 PTCD0
$0009 PTCPE PTCPE7 PTCPE6 PTCPE5 PTCPE4 PTCPE3 PTCPE2 PTCPE1 PTCPE0
$000A Reserved — — — — — — — —
$000B PTCDD PTCDD7 PTCDD6 PTCDD5 PTCDD4 PTCDD3 PTCDD2 PTCDD1 PTCDD0
$000C PTDD 0 PTDD6 PTDD5 PTDD4 PTDD3 PTDD2 PTDD1 PTDD0
$000D PTDPE 0 PTDPE6 PTDPE5 PTDPE4 PTDPE3 PTDPE2 PTDPE1 PTDPE0
$000E Reserved — — — — — — — —
$000F PTDDD 0 PTDDD6 PTDDD5 PTDDD4 PTDDD3 PTDDD2 PTDDD1 PTDDD0
$0010 PTED PTED7 PTED6 PTED5 PTED4 PTED3 PTED2 PTED1 PTED0
$0011 PTEPE PTEPE7 PTEPE6 PTEPE5 PTEPE4 PTEPE3 PTEPE2 PTEPE1 PTEPE0
$0012 Reserved — — — — — — — —
$0013 PTEDD PTEDD7 PTEDD6 PTEDD5 PTEDD4 PTEDD3 PTEDD2 PTEDD1 PTEDD0
$0014 KBI1SC KBEDG7 KBEDG6 KBEDG5 KBEDG4 KBF KBACK KBIE KBIMOD
$0015 KBI1PE KBIPE7 KBIPE6 KBIPE5 KBIPE4 KBIPE3 KBIPE2 KBIPE1 KBIPE0
$0016 KBI2SC 0 0 0 0 KBF KBACK KBIE KBIMOD
$0017 KBI2PE 0 0 0 0 KBIPE3 KBIPE2 KBIPE1 KBIPE0
$0018 SCI1BDH(1) 0 0 0 SBR12 SBR11 SBR10 SBR9 SBR8
$0019 SCI1BDL(1) SBR7 SBR6 SBR5 SBR4 SBR3 SBR2 SBR1 SBR0
$001A SCI1C1(1) LOOPS SCISWAI RSRC M WAKE ILT PE PT
$001B SCI1C2(1) TIE TCIE RIE ILIE TE RE RWU SBK
$001C SCI1S1(1) TDRE TC RDRF IDLE OR NF FE PF
$001D SCI1S2(1) 0 0 0 0 0 0 0 RAF
$001E SCI1C3(1) R8 T8 TXDIR 0 ORIE NEIE FEIE PEIE
$001F SCI1D(1) R7/T7 R6/T6 R5/T5 R4/T4 R3/T3 R2/T2 R1/T1 R0/T0
$0020 CMTCGH1 PH7 PH6 PH5 PH4 PH3 PH2 PH1 PH0
$0021 CMTCGL1 PL7 PL6 PL5 PL4 PL3 PL2 PL1 PL0
$0022 CMTCGH2 SH7 SH6 SH5 SH4 SH3 SH2 SH1 SH0
$0023 CMTCGL2 SL7 SL6 SL5 SL4 SL3 SL2 SL1 SL0
$0024 CMTOC IROL CMTPOL IROPEN 00000
$0025 CMTMSC EOCF CMTDIV1 CMTDIV0 EXSPC BASE FSK EOCIE MCGEN
$0026 CMTCMD1 MB15 MB14 MB13 MB12 MB11 MB10 MB9 MB8
$0027 CMTCMD2 MB7 MB6 MB5 MB4 MB3 MB2 MB1 MB0
$0028 CMTCMD3 SB15 SB14 SB13 SB12 SB11 SB10 SB9 SB8
$0029 CMTCMD4 SB7 SB6 SB5 SB4 SB3 SB2 SB1 SB0
Memory
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
40 Freescale Semiconductor
High-page registers, shown in Table 4-2, are accessed much less often than other I/O and control registers
so they have been located outside the direct addressable memory space, starting at $1800.
$002A IRQSC 0 0 IRQEDG IRQPE IRQF IRQACK IRQIE IRQMOD
$002B ACMP1SC(2) ACME ACBGS ACF ACIE ACO — ACMOD1 ACMOD0
$002C–
$002F
Reserved —
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
$0030 TPM1SC TOF TOIE CPWMS CLKSB CLKSAPS2 PS1 PS0
$0031 TPM1CNTH Bit 15 14 13 12 11 10 9 Bit 8
$0032 TPM1CNTL Bit 7 654321Bit 0
$0033 TPM1MODH Bit 15 14 13 12 11 10 9 Bit 8
$0034 TPM1MODL Bit 7 654321Bit 0
$0035 TPM1C0SC CH0F CH0IE MS0B MS0A ELS0B ELS0A 0 0
$0036 TPM1C0VH Bit 15 14 13 12 11 10 9 Bit 8
$0037 TPM1C0VL Bit 7 654321Bit 0
$0038 TPM1C1SC CH1F CH1IE MS1B MS1A ELS1B ELS1A 0 0
$0039 TPM1C1VH Bit 15 14 13 12 11 10 9 Bit 8
$003A TPM1C1VL Bit 7 654321Bit 0
$003B–
$003F
Reserved —
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
$0040 SPI1C1(3) SPIE SPE SPTIE MSTR CPOL CPHA SSOE LSBFE
$0041 SPI1C2(3) 0 0 0 MODFEN BIDIROE 0 SPISWAI SPC0
$0042 SPI1BR(3) 0 SPPR2 SPPR1 SPPR0 0 SPR2 SPR1 SPR0
$0043 SPI1S(3) SPRF 0 SPTEF MODF 0 0 0 0
$0044 Reserved — — — — — — — —
$0045 SPI1D(3) Bit 7 654321Bit 0
1. The SCI module is not included on the MC9S08RC devices. This is a reserved location for those devices.
2. The analog comparator (ACMP) module is not included on the MC9S08RD devices. This is a reserved location for those
devices.
3. The SPI module is not included on the MC9S08RC/RD/RE devices. These are reserved locations on the 32K and 60K versions
of these devices. The address range $0040–$004F are RAM locations on the 16K and 8K devices. There are no
MC9S08RG8/16 devices.
Table 4-2. High-Page Register Summary
Address Register Name Bit 7 654321Bit 0
$1800 SRS POR PIN COP ILOP ILAD(1) 0LVD0
$1801 SBDFR 0 0 0 0 0 0 0 BDFR
$1802 SOPT 7 COPT STOPE — 0 0 BKGDPE RSTPE
$1803–
$1804
Reserved —
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
$1805 Reserved 0 0 0 0 0 0 0 0
$1806 SDIDH REV3 REV2 REV1 REV0 ID11 ID10 ID9 ID8
$1807 SDIDL ID7 ID6 ID5 ID4 ID3 ID2 ID1 ID0
$1808 SRTISC RTIF RTIACK RTICLKS RTIE 0 RTIS2 RTIS1 RTIS0
Table 4-1. Direct-Page Register Summary (continued)
Address Register Name Bit 7 654321Bit 0
Memory
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 41
Nonvolatile FLASH registers, shown in Table 4-3, are located in the FLASH memory. These registers
include an 8-byte backdoor key that optionally can be used to gain access to secure memory resources.
During reset events, the contents of NVPROT and NVOPT in the nonvolatile register area of the FLASH
memory are transferred into corresponding FPROT and FOPT working registers in the high-page registers
to control security and block protection options.
$1809 SPMSC1 LVDF LVDACK LVDIE SAFE LVDRE — — —
$180A SPMSC2 LVWF LVWACK 0 0 PPDF PPDACK PDC PPDC
$180B–
$180F
Reserved —
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
$1810 DBGCAH Bit 15 14 13 12 11 10 9 Bit 8
$1811 DBGCAL Bit 7 654321Bit 0
$1812 DBGCBH Bit 15 14 13 12 11 10 9 Bit 8
$1813 DBGCBL Bit 7 654321Bit 0
$1814 DBGFH Bit 15 14 13 12 11 10 9 Bit 8
$1815 DBGFL Bit 7 654321Bit 0
$1816 DBGC DBGEN ARM TAG BRKEN RWA RWAEN RWB RWBEN
$1817 DBGT TRGSEL BEGIN 0 0 TRG3 TRG2 TRG1 TRG0
$1818 DBGS AF BF ARMF 0 CNT3 CNT2 CNT1 CNT0
$1819–
$181F
Reserved —
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
$1820 FCDIV DIVLD PRDIV8 DIV5 DIV4 DIV3 DIV2 DIV1 DIV0
$1821 FOPT KEYEN FNORED 0 0 0 0 SEC01 SEC00
$1822 Reserved ————————
$1823 FCNFG 0 0 KEYACC 0 0 0 0 0
$1824 FPROT FPOPEN FPDIS FPS2 FPS1 FPS0 000
$1825 FSTAT FCBEF FCCF FPVIOL FACCERR 0 FBLANK 0 0
$1826 FCMD FCMD7 FCMD6 FCMD5 FCMD4 FCMD3 FCMD2 FCMD1 FCMD0
$1827–
$182B
Reserved —
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
1. The ILAD bit is only present on 16K and 8K versions of the devices.
Table 4-3. Nonvolatile Register Summary
Address Register Name Bit 7 654321Bit 0
$FFB0–
$FFB7
NVBACKKEY 8-Byte Comparison Key
$FFB8–
$FFBC
Reserved —
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
$FFBD NVPROT FPOPEN FPDIS FPS2 FPS1 FPS0 000
$FFBE Reserved ————————
$FFBF NVOPT KEYEN FNORED 0 0 0 0 SEC01 SEC00
Table 4-2. High-Page Register Summary (continued)
Address Register Name Bit 7 654321Bit 0
Memory
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
42 Freescale Semiconductor
Provided the key enable (KEYEN) bit is 1, the 8-byte comparison key can be used to temporarily
disengage memory security. This key mechanism can be accessed only through user code running in secure
memory. (A security key cannot be entered directly through background debug commands.) This security
key can be disabled completely by programming the KEYEN bit to 0. If the security key is disabled, the
only way to disengage security is by mass erasing the FLASH if needed (normally through the background
debug interface) and verifying that FLASH is blank. To avoid returning to secure mode after the next reset,
program the security bits (SEC01:SEC00) to the unsecured state (1:0).
4.3 RAM
The MC9S08RC/RD/RE/RG includes static RAM. The locations in RAM below $0100 can be accessed
using the more efficient direct addressing mode, and any single bit in this area can be accessed with the
bit-manipulation instructions (BCLR, BSET, BRCLR, and BRSET). Locating the most frequently
accessed program variables in this area of RAM is preferred.
The RAM retains data when the MCU is in low-power wait, stop2, or stop3 mode. At power-on or after
wakeup from stop1, the contents of RAM are uninitialized. RAM data is unaffected by any reset provided
that the supply voltage does not drop below the minimum value for RAM retention.
For compatibility with older M68HC05 MCUs, the HCS08 resets the stack pointer to $00FF. In the
MC9S08RC/RD/RE/RG, it is usually best to reinitialize the stack pointer to the top of the RAM so the
direct page RAM can be used for frequently accessed RAM variables and bit-addressable program
variables. Include the following 2-instruction sequence in your reset initialization routine (where RamLast
is equated to the highest address of the RAM in the Freescale-provided equate file).
LDHX #RamLast+1 ;point one past RAM
TXS ;SP<-(H:X-1)
When security is enabled, the RAM is considered a secure memory resource and is not accessible through
BDM or through code executing from non-secure memory. See Section 4.5, “Security,” for a detailed
description of the security feature.
4.4 FLASH
The FLASH memory is intended primarily for program storage. In-circuit programming allows the
operating program to be loaded into the FLASH memory after final assembly of the application product.
It is possible to program the entire array through the single-wire background debug interface. Because no
special voltages are needed for FLASH erase and programming operations, in-application programming
is also possible through other software-controlled communication paths. For a more detailed discussion of
in-circuit and in-application programming, refer to the HCS08 Family Reference Manual, Volume I,
Freescale Semiconductor document order number HCS08RMv1/D.
Memory
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 43
4.4.1 Features
Features of the FLASH memory include:
• FLASH Size
— MC9S08RC/RD/RE/RG60 — 63374 bytes (124 pages of 512 bytes each)
— MC9S08RC/RD/RE/RG32 — 32768 bytes (64 pages of 512 bytes each)
— MC9S08RC/RD/RE16 — 16384 bytes (32 pages of 512 bytes each)
— MC9S08RC/RD/RE8 — 8192 bytes (16 pages of 512 bytes each)
• Single power supply program and erase
• Command interface for fast program and erase operation
• Up to 100,000 program/erase cycles at typical voltage and temperature
• Flexible block protection
• Security feature for FLASH and RAM
• Auto power-down for low-frequency read accesses
4.4.2 Program and Erase Times
Before any program or erase command can be accepted, the FLASH clock divider register (FCDIV) must
be written to set the internal clock for the FLASH module to a frequency (fFCLK) between 150 kHz and
200 kHz (see Section 4.6.1, “FLASH Clock Divider Register (FCDIV)”). This register can be written only
once, so normally this write is done during reset initialization. FCDIV cannot be written if the access error
flag, FACCERR in FSTAT, is set. The user must ensure that FACCERR is not set before writing to the
FCDIV register. One period of the resulting clock (1/fFCLK) is used by the command processor to time
program and erase pulses. An integer number of these timing pulses are used by the command processor
to complete a program or erase command.
Table 4-4 shows program and erase times. The bus clock frequency and FCDIV determine the frequency
of FCLK (fFCLK). The time for one cycle of FCLK is tFCLK = 1/fFCLK. The times are shown as a number
of cycles of FCLK and as an absolute time for the case where tFCLK =5µs. Program and erase times
shown include overhead for the command state machine and enabling and disabling of program and erase
voltages.
Table 4-4. Program and Erase Times
Parameter Cycles of FCLK Time if FCLK = 200 kHz
Byte program 9 45 µs
Byte program (burst) 4 20 µs(1)
1. Excluding start/end overhead
Page erase 4000 20 ms
Mass erase 20,000 100 ms
Memory
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
44 Freescale Semiconductor
4.4.3 Program and Erase Command Execution
The steps for executing any of the commands are listed below. The FCDIV register must be initialized and
any error flags cleared before beginning command execution. The command execution steps are:
1. Write a data value to an address in the FLASH array. The address and data information from this
write is latched into the FLASH interface. This write is a required first step in any command
sequence. For erase and blank check commands, the value of the data is not important. For page
erase commands, the address may be any address in the 512-byte page of FLASH to be erased. For
mass erase and blank check commands, the address can be any address in the FLASH memory.
Whole pages of 512 bytes are the smallest block of FLASH that may be erased. In the 60K version,
there are two instances where the size of a block that is accessible to the user is less than 512 bytes:
the first page following RAM, and the first page following the high page registers. These pages are
overlapped by the RAM and high page registers respectively.
NOTE
Do not program any byte in the FLASH more than once after a successful
erase operation. Reprogramming bits to a byte which is already
programmed is not allowed without first erasing the page in which the byte
resides or mass erasing the entire FLASH memory. Programming without
first erasing may disturb data stored in the FLASH.
2. Write the command code for the desired command to FCMD. The five valid commands are blank
check ($05), byte program ($20), burst program ($25), page erase ($40), and mass erase ($41). The
command code is latched into the command buffer.
3. Write a 1 to the FCBEF bit in FSTAT to clear FCBEF and launch the command (including its
address and data information).
A partial command sequence can be aborted manually by writing a 0 to FCBEF any time after the write to
the memory array and before writing the 1 that clears FCBEF and launches the complete command.
Aborting a command in this way sets the FACCERR access error flag, which must be cleared before
starting a new command.
A strictly monitored procedure must be adhered to, or the command will not be accepted. This minimizes
the possibility of any unintended changes to the FLASH memory contents. The command complete flag
(FCCF) indicates when a command is complete. The command sequence must be completed by clearing
FCBEF to launch the command. Figure 4-3 is a flowchart for executing all of the commands except for
burst programming. The FCDIV register must be initialized before using any FLASH commands. This
must be done only once following a reset.
Memory
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 45
Figure 4-3. FLASH Program and Erase Flowchart
4.4.4 Burst Program Execution
The burst program command is used to program sequential bytes of data in less time than would be
required using the standard program command. This is possible because the high voltage to the FLASH
array does not need to be disabled between program operations. Ordinarily, when a program or erase
command is issued, an internal charge pump associated with the FLASH memory must be enabled to
supply high voltage to the array. Upon completion of the command, the charge pump is turned off. When
a burst program command is issued, the charge pump is enabled and remains enabled after completion of
the burst program operation if the following two conditions are met:
• The new burst program command has been queued before the current program operation
completes.
• The next sequential address selects a byte on the same physical row as the current byte being
programmed. A row of FLASH memory consists of 64 bytes. A byte within a row is selected by
addresses A5 through A0. A new row begins when addresses A5 through A0 are all zero.
The first byte of a series of sequential bytes being programmed in burst mode will take the same amount
of time to program as a byte programmed in standard mode. Subsequent bytes will program in the burst
START
WRITE TO FLASH
TO BUFFER ADDRESS AND DATA
WRITE COMMAND TO FCMD
NO
YES
FPVIO OR
WRITE 1 TO FCBEF
TO LAUNCH COMMAND
AND CLEAR FCBEF (2)
1
0
FCCF ?
ERROR EXIT
DONE
(2) Wait at least four cycles before
checking FCBEF or FCCF.
0
FACCERR ?
CLEAR ERROR
FACCERR ?
WRITE TO FCDIV(1) (1) Required only once
after reset.
Memory
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
46 Freescale Semiconductor
program time provided that the conditions above are met. In the case where the next sequential address is
the beginning of a new row, the program time for that byte will be the standard time instead of the burst
time. This is because the high voltage to the array must be disabled and then enabled again. If a new burst
command has not been queued before the current command completes, then the charge pump will be
disabled and high voltage removed from the array.
Figure 4-4. FLASH Burst Program Flowchart
4.4.5 Access Errors
An access error occurs whenever the command execution protocol is violated.
Any of the following specific actions will cause the access error flag (FACCERR) in FSTAT to be set.
FACCERR must be cleared by writing a 1 to FACCERR in FSTAT before any command can be processed:
1
0
FCBEF ?
START
WRITE TO FLASH
TO BUFFER ADDRESS AND DATA
WRITE COMMAND TO FCMD
NO
YES
FPVIO OR
WRITE 1 TO FCBEF
TO LAUNCH COMMAND
AND CLEAR FCBEF (2)
NO
YES
NEW BURST COMMAND ?
1
0
FCCF ?
ERROR EXIT
DONE
(2) Wait at least four cycles before
checking FCBEF or FCCF.
1
0
FACCERR ?
CLEAR ERROR
FACCERR ?
WRITE TO FCDIV(1) (1) Required only once
after reset.
Memory
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 47
• Writing to a FLASH address before the internal FLASH clock frequency has been set by writing
to the FCDIV register
• Writing to a FLASH address while FCBEF is not set (A new command cannot be started until the
command buffer is empty.)
• Writing a second time to a FLASH address before launching the previous command (There is only
one write to FLASH for every command.)
• Writing a second time to FCMD before launching the previous command (There is only one write
to FCMD for every command.)
• Writing to any FLASH control register other than FCMD after writing to a FLASH address
• Writing any command code other than the five allowed codes ($05, $20, $25, $40, or $41) to
FCMD
• Accessing (read or write) any FLASH control register other than the write to FSTAT (to clear
FCBEF and launch the command) after writing the command to FCMD
• The MCU enters stop mode while a program or erase command is in progress (The command is
aborted.)
• Writing the byte program, burst program, or page erase command code ($20, $25, or $40) with a
background debug command while the MCU is secured (The background debug controller can
only do blank check and mass erase commands when the MCU is secure.)
• Writing 0 to FCBEF to cancel a partial command
4.4.6 FLASH Block Protection
Block protection prevents program or erase changes for FLASH memory locations in a designated address
range. Mass erase is disabled when any block of FLASH is protected. The MC9S08RC/RD/RE/RG allows
a block of memory at the end of FLASH, and/or the entire FLASH memory to be block protected. A
disable control bit and a 3-bit control field, for each of the blocks, allows the user to independently set the
size of these blocks. A separate control bit allows block protection of the entire FLASH memory array. All
seven of these control bits are located in the FPROT register (see Section 4.6.4, “FLASH Protection
Register (FPROT and NVPROT)“).
At reset, the high-page register (FPROT) is loaded with the contents of the NVPROT location that is in the
nonvolatile register block of the FLASH memory. The value in FPROT cannot be changed directly from
application software so a runaway program cannot alter the block protection settings. If the last 512 bytes
of FLASH (which includes the NVPROT register) is protected, the application program cannot alter the
block protection settings (intentionally or unintentionally). The FPROT control bits can be written by
background debug commands to allow a way to erase a protected FLASH memory.
One use for block protection is to block protect an area of FLASH memory for a bootloader program. This
bootloader program then can be used to erase the rest of the FLASH memory and reprogram it. Because
the bootloader is protected, it remains intact even if MCU power is lost during an erase and reprogram
operation.
Memory
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
48 Freescale Semiconductor
4.4.7 Vector Redirection
Whenever any block protection is enabled, the reset and interrupt vectors will be protected. For this reason,
a mechanism for redirecting vector reads is provided. Vector redirection allows users to modify interrupt
vector information without unprotecting bootloader and reset vector space. For redirection to occur, at least
some portion but not all of the FLASH memory must be block protected by programming the NVPROT
register located at address $FFBD. All of the interrupt vectors (memory locations $FFC0–$FFFD) are
redirected, while the reset vector ($FFFE:FFFF) is not.
For example, if 512 bytes of FLASH are protected, the protected address region is from $FE00 through
$FFFF. The interrupt vectors ($FFC0–$FFFD) are redirected to the locations $FDC0–$FDFD. Now, if an
SPI interrupt is taken for instance, the values in the locations $FDE0:FDE1 are used for the vector instead
of the values in the locations $FFE0:FFE1. This allows the user to reprogram the unprotected portion of
the FLASH with new program code including new interrupt vector values while leaving the protected area,
which includes the default vector locations, unchanged.
4.5 Security
The MC9S08RC/RD/RE/RG includes circuitry to prevent unauthorized access to the contents of FLASH
and RAM memory. When security is engaged, FLASH and RAM are considered secure resources.
Direct-page registers, high-page registers, and the background debug controller are considered unsecured
resources. Programs executing within secure memory have normal access to any MCU memory locations
and resources. Attempts to access a secure memory location with a program executing from an unsecured
memory space or through the background debug interface are blocked (writes are ignored and reads return
all 0s).
Security is engaged or disengaged based on the state of two nonvolatile register bits (SEC01:SEC00) in
the FOPT register. During reset, the contents of the nonvolatile location NVOPT are copied from FLASH
into the working FOPT register in high-page register space. A user engages security by programming the
NVOPT location, which can be done at the same time the FLASH memory is programmed. The 1:0 state
disengages security while the other three combinations engage security. Notice the erased state (1:1)
makes the MCU secure. During development, whenever the FLASH is erased, it is good practice to
immediately program the SEC00 bit to 0 in NVOPT so SEC01:SEC00 = 1:0. This would allow the MCU
to remain unsecured after a subsequent reset.
The on-chip debug module cannot be enabled while the MCU is secure. The separate background debug
controller can still be used for background memory access commands, but the MCU cannot enter active
background mode except by holding BKGD/MS low at the rising edge of reset.
A user can choose to allow or disallow a security unlocking mechanism through an 8-byte backdoor
security key. If the nonvolatile KEYEN bit in NVOPT/FOPT is 0, the backdoor key is disabled and there
is no way to disengage security without completely erasing all FLASH locations. If KEYEN is 1, a secure
user program can temporarily disengage security by:
1. Writing 1 to KEYACC in the FCNFG register. This makes the FLASH module interpret writes to
the backdoor comparison key locations (NVBACKKEY through NVBACKKEY+7) as values to
be compared against the key rather than as the first step in a FLASH program or erase command.
Memory
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 49
2. Writing the user-entered key values to the NVBACKKEY through NVBACKKEY+7 locations.
These writes must be done in order starting with the value for NVBACKKEY and ending with
NVBACKKEY+7. STHX must not be used for these writes because these writes cannot be done
on adjacent bus cycles. User software normally would get the key codes from outside the MCU
system through a communication interface such as a serial I/O.
3. Writing 0 to KEYACC in the FCNFG register. If the 8-byte key that was just written matches the
key stored in the FLASH locations, SEC01:SEC00 are automatically changed to 1:0 and security
will be disengaged until the next reset.
The security key can be written only from RAM, so it cannot be entered through background commands
without the cooperation of a secure user program. The FLASH memory cannot be accessed by read
operations while KEYACC is set.
The backdoor comparison key (NVBACKKEY through NVBACKKEY+7) is located in FLASH memory
locations in the nonvolatile register space so users can program these locations exactly as they would
program any other FLASH memory location. The nonvolatile registers are in the same 512-byte block of
FLASH as the reset and interrupt vectors, so block protecting that space also block protects the backdoor
comparison key. Block protects cannot be changed from user application programs, so if the vector space
is block protected, the backdoor security key mechanism cannot permanently change the block protect,
security settings, or the backdoor key.
Security can always be disengaged through the background debug interface by performing these steps:
1. Disable any block protections by writing FPROT. FPROT can be written only with background
debug commands, not from application software.
2. Mass erase FLASH if necessary.
3. Blank check FLASH. Provided FLASH is completely erased, security is disengaged until the next
reset.
To avoid returning to secure mode after the next reset, program NVOPT so SEC01:SEC00 = 1:0.
4.6 FLASH Registers and Control Bits
The FLASH module has nine 8-bit registers in the high-page register space, three locations in the
nonvolatile register space in FLASH memory that are copied into three corresponding high-page control
registers at reset. There is also an 8-byte comparison key in FLASH memory. Refer to Table 4-2 and
Table 4-3 for the absolute address assignments for all FLASH registers. This section refers to registers and
control bits only by their names. A Freescale-provided equate or header file normally is used to translate
these names into the appropriate absolute addresses.
4.6.1 FLASH Clock Divider Register (FCDIV)
Bit 7 of this register is a read-only status flag. Bits 6 through 0 may be read at any time but can be written
only one time. Before any erase or programming operations are possible, write to this register to set the
frequency of the clock for the nonvolatile memory system within acceptable limits.
Memory
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
50 Freescale Semiconductor
if PRDIV8 = 0 — fFCLK = fBus ÷ ([DIV5:DIV0] + 1) Eqn. 4-1
if PRDIV8 = 1 — fFCLK = fBus ÷ (8 × ([DIV5:DIV0] + 1)) Eqn. 4-2
Table 4-6 shows the appropriate values for PRDIV8 and DIV5:DIV0 for selected bus frequencies.
76543210
R DIVLD
PRDIV8 DIV5 DIV4 DIV3 DIV2 DIV1 DIV0
W
Reset 00000000
= Unimplemented or Reserved
Figure 4-5. FLASH Clock Divider Register (FCDIV)
Table 4-5. FCDIV Field Descriptions
Field Description
7
DIVLD
Divisor Loaded Status Flag — When set, this read-only status flag indicates that the FCDIV register has been
written since reset. Reset clears this bit and the first write to this register causes this bit to become set regardless
of the data written.
0 FCDIV has not been written since reset; erase and program operations disabled for FLASH.
1 FCDIV has been written since reset; erase and program operations enabled for FLASH.
6
PRDIV8
Prescale (Divide) FLASH Clock by 8
0 Clock input to the FLASH clock divider is the bus rate clock.
1 Clock input to the FLASH clock divider is the bus rate clock divided by 8.
5:0
DIV[5:0]
Divisor for FLASH Clock Divider — The FLASH clock divider divides the bus rate clock (or the bus rate clock
divided by 8 if PRDIV8 = 1) by the value in the 6-bit DIV5:DIV0 field plus one. The resulting frequency of the
internal FLASH clock must fall within the range of 200 kHz to 150 kHz for proper FLASH operations.
Program/erase timing pulses are one cycle of this internal FLASH clock, which corresponds to a range of 5 µs
to 6.7 µs. The automated programming logic uses an integer number of these pulses to complete an erase or
program operation. See Equation 4-1 and Equation 4-2.
Table 4-6. FLASH Clock Divider Settings
fBus
PRDIV8
(Binary)
DIV5:DIV0
(Decimal) fFCLK
Program/Erase Timing Pulse
(5 µs Min, 6.7 µs Max)
8 MHz 0 39 200 kHz 5 µs
4 MHz 0 19 200 kHz 5 µs
2 MHz 0 9 200 kHz 5 µs
1 MHz 0 4 200 kHz 5 µs
200 kHz 0 0 200 kHz 5 µs
150 kHz 0 0 150 kHz 6.7 µs
Memory
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 51
4.6.2 FLASH Options Register (FOPT and NVOPT)
During reset, the contents of the nonvolatile location NVOPT are copied from FLASH into FOPT. Bits 5
through 2 are not used and always read 0. This register may be read at any time, but writes have no meaning
or effect. To change the value in this register, erase and reprogram the NVOPT location in FLASH memory
as usual and then issue a new MCU reset.
4.6.3 FLASH Configuration Register (FCNFG)
Bits 7 through 5 may be read or written at any time. Bits 4 through 0 always read 0 and cannot be written.
76543210
R KEYEN FNORED 0000SEC01 SEC00
W
Reset This register is loaded from nonvolatile location NVOPT during reset.
= Unimplemented or Reserved
Figure 4-6. FLASH Options Register (FOPT)
Table 4-7. FOPT Field Descriptions
Field Description
7
KEYEN
Backdoor Key Mechanism Enable — When this bit is 0, the backdoor key mechanism cannot be used to
disengage security. The backdoor key mechanism is accessible only from user (secured) firmware. BDM
commands cannot be used to write key comparison values that would unlock the backdoor key. For more detailed
information about the backdoor key mechanism, refer to Section 4.5, “Security."
0 No backdoor key access allowed.
1 If user firmware writes an 8-byte value that matches the nonvolatile backdoor key (NVBACKKEY through
NVBACKKEY+7 in that order), security is temporarily disengaged until the next MCU reset.
6
FNORED
Vector Redirection Disable — When this bit is 1, then vector redirection is disabled.
0 Vector redirection enabled.
1 Vector redirection disabled.
1:0
SEC0[1:0]
Security State Code — This 2-bit field determines the security state of the MCU as shown below. When the
MCU is secure, the contents of RAM and FLASH memory cannot be accessed by instructions from any
unsecured source including the background debug interface. For more detailed information about security, refer
to Section 4.5, “Security.”
00 Secure
01 Secure
10 Unsecured
11 Secure
SEC01:SEC00 changes to 1:0 after successful backdoor key entry or a successful blank check of FLASH.
Memory
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
52 Freescale Semiconductor
4.6.4 FLASH Protection Register (FPROT and NVPROT)
During reset, the contents of the nonvolatile location NVPROT is copied from FLASH into FPROT. Bits 0,
1, and 2 are not used and each always reads as 0. This register may be read at any time, but user program
writes have no meaning or effect. Background debug commands can write to FPROT at $1824.
76543210
R
KEYACC
W
Reset 00000000
= Unimplemented or Reserved
Figure 4-7. FLASH Configuration Register (FCNFG)
Table 4-8. FCNFG Field Descriptions
Field Description
5
KEYACC
Enable Writing of Access Key — This bit enables writing of the backdoor comparison key. For more detailed
information about the backdoor key mechanism, refer to Section 4.5, “Security."
0 Writes to $FFB0–$FFB7 are interpreted as the start of a FLASH programming or erase command.
1 Writes to NVBACKKEY ($FFB0–$FFB7) are interpreted as comparison key writes.
Reads of the FLASH return invalid data.
76543210
RFPOPEN FPDIS FPS2 FPS1 FPS0 0 0 0
W(1)
1. Background commands can be used to change the contents of these bits in FPROT.
(1) (1) (1) (1)
Reset This register is loaded from nonvolatile location NVPROT during reset.
= Unimplemented or Reserved
Figure 4-8. FLASH Protection Register (FPROT)
Table 4-9. FPROT Field Descriptions
Field Description
7
FPOPEN
Open Unprotected FLASH for Program/Erase
0 Entire FLASH memory is block protected (no program or erase allowed).
1 Any FLASH location, not otherwise block protected or secured, may be erased or programmed.
6
FPDIS
FLASH Protection Disable
0 FLASH block specified by FPS2:FPS0 is block protected (program and erase not allowed).
1 No FLASH block is protected.
5:3
FPS[2:0]
FLASH Protect Size Selects — When FPDIS = 0, this 3-bit field determines the size of a protected block of
FLASH locations at the high address end of the FLASH (see Table 4-10 and Table 4-11). Protected FLASH
locations cannot be erased or programmed.
Memory
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 53
Table 4-10. High Address Protected Block for 32K and 60K Versions
FPS2:FPS1:FPS0 Protected Address Range Protected Block Size Redirected Vectors(1)
1. No redirection if FPOPEN = 0, or FNORED = 1.
0:0:0 $FE00–$FFFF 512 bytes $FDC0–$FDFD(2)
2. Reset vector is not redirected.
0:0:1 $FC00–$FFFF 1 Kbytes $FBC0–$FBFD
0:1:0 $F800–$FFFF 2 Kbytes $F7C0–$F7FD
0:1:1 $F000–$FFFF 4 Kbytes $EFC0–$EFFD
1:0:0 $E000–$FFFF 8 Kbytes $DFC0–$DFFD
1:0:1 $C000–$FFFF 16 Kbytes $BFC0–$BFFD
1:1:0(3)
3. Use for 60K version only. When protecting all of 32K version memory, use FPOPEN = 0.
$8000–$FFFF 32 Kbytes $7FC0–$7FFD
1:1:1(3) $8000–$FFFF 32 Kbytes $7FC0–$7FFD
Table 4-11. High Address Protected Block for 8K and 16K Version
FPS2:FPS1:FPS0 Protected Address Range Protected Block Size Redirected Vectors(1)
1. No redirection if FPOPEN = 0, or FNORED = 1.
0:0:0 $FE00–$FFFF 512 bytes $FDC0–$FDFD(2)
2. Reset vector is not redirected.
0:0:1 $FC00–$FFFF 1 Kbytes $FBC0–$FBFD
0:1:0 $F800–$FFFF 2 Kbytes $F7C0–$F7FD
0:1:1 $F000–$FFFF 4 Kbytes $EFC0–$EFFD
1:0:0(3)
3. Use for 60K version only. When protecting all of 32K version memory, use FPOPEN = 0.
$E000–$FFFF 8 Kbytes $DFC0–$DFFD
1:0:1(3) $E000–$FFFF 8 Kbytes $DFC0–$DFFD
1:1:0(3) $E000–$FFFF 8 Kbytes $DFC0–$DFFD
1:1:1(3) $E000–$FFFF 8 Kbytes $DFC0–$DFFD
Memory
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
54 Freescale Semiconductor
4.6.5 FLASH Status Register (FSTAT)
Bits 3, 1, and 0 always read 0 and writes have no meaning or effect. The remaining five bits are status bits
that can be read at any time. Writes to these bits have special meanings that are discussed in the bit
descriptions.
76543210
R
FCBEF
FCCF
FPVIOL FACCERR
0 FBLANK 0 0
W
Reset 11000000
= Unimplemented or Reserved
Figure 4-9. FLASH Status Register (FSTAT)
Table 4-12. FSTAT Field Descriptions
Field Description
7
FCBEF
FLASH Command Buffer Empty Flag — The FCBEF bit is used to launch commands. It also indicates that the
command buffer is empty so that a new command sequence can be executed when performing burst
programming. The FCBEF bit is cleared by writing a 1 to it or when a burst program command is transferred to
the array for programming. Only burst program commands can be buffered.
0 Command buffer is full (not ready for additional commands).
1 A new burst program command may be written to the command buffer.
6
FCCF
FLASH Command Complete Flag — FCCF is set automatically when the command buffer is empty and no
command is being processed. FCCF is cleared automatically when a new command is started (by writing 1 to
FCBEF to register a command). Writing to FCCF has no meaning or effect.
0 Command in progress
1 All commands complete
5
FPVIOL
Protection Violation Flag — FPVIOL is set automatically when FCBEF is cleared to register a command that
attempts to erase or program a location in a protected block (the erroneous command is ignored). FPVIOL is
cleared by writing a 1 to FPVIOL.
0 No protection violation.
1 An attempt was made to erase or program a protected location.
4
FACCERR
Access Error Flag — FACCERR is set automatically when the proper command sequence is not followed
exactly (the erroneous command is ignored), if a program or erase operation is attempted before the FCDIV
register has been initialized, or if the MCU enters stop while a command was in progress. For a more detailed
discussion of the exact actions that are considered access errors, see Section 4.4.5, “Access Errors." FACCERR
is cleared by writing a 1 to FACCERR. Writing a 0 to FACCERR has no meaning or effect.
0 No access error.
1 An access error has occurred.
2
FBLANK
FLASH Verified as All Blank (erased) Flag — FBLANK is set automatically at the conclusion of a blank check
command if the entire FLASH array was verified to be erased. FBLANK is cleared by clearing FCBEF to write a
new valid command. Writing to FBLANK has no meaning or effect.
0 After a blank check command is completed and FCCF = 1, FBLANK = 0 indicates the FLASH array is not
completely erased.
1 After a blank check command is completed and FCCF = 1, FBLANK = 1 indicates the FLASH array is
completely erased (all $FF).
Memory
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 55
4.6.6 FLASH Command Register (FCMD)
Only four command codes are recognized in normal user modes as shown in Table 4-14. Refer to
Section 4.4.3, “Program and Erase Command Execution,” for a detailed discussion of FLASH
programming and erase operations.
All other command codes are illegal and generate an access error.
It is not necessary to perform a blank check command after a mass erase operation. Only blank check is
required as part of the security unlocking mechanism.
76543210
R00000000
W FCMD7 FCMD6 FCMD5 FCMD4 FCMD3 FCMD2 FCMD1 FCMD0
Reset 00000000
Figure 4-10. FLASH Command Register (FCMD)
Table 4-13. FCMD Field Descriptions
Field Description
7:0
FCMD[7:0]
See Table 4-14 for FLASH commands.
Table 4-14. FLASH Commands
Command FCMD Equate File Label
Blank check $05 mBlank
Byte program $20 mByteProg
Byte program – burst mode $25 mBurstProg
Page erase (512 bytes/page) $40 mPageErase
Mass erase (all FLASH) $41 mMassErase
Memory
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
56 Freescale Semiconductor
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 57
Chapter 5
Resets, Interrupts, and System Configuration
5.1 Introduction
This section discusses basic reset and interrupt mechanisms and the various sources of reset and interrupts
in the MC9S08RC/RD/RE/RG. Some interrupt sources from peripheral modules are discussed in greater
detail within other sections of this data sheet. This section gathers basic information about all reset and
interrupt sources in one place for easy reference. A few reset and interrupt sources, including the computer
operating properly (COP) watchdog and real-time interrupt (RTI), are not part of on-chip peripheral
systems having their own sections but are part of the system control logic.
5.2 Features
Reset and interrupt features include:
• Multiple sources of reset for flexible system configuration and reliable operation:
— Power-on detection (POR)
— Low voltage detection (LVD) with enable
— External reset pin with enable (RESET)
— COP watchdog with enable and two timeout choices
— Illegal opcode
— Illegal address (on 16K and 8K devices)
— Serial command from a background debug host
• Reset status register (SRS) to indicate source of most recent reset; flag to indicate stop2 (partial
power down) mode recovery (PPDF)
• Separate interrupt vectors for each module (reduces polling overhead) (see Table 5-1)
• Safe state for protecting the MCU in low-voltage condition
5.3 MCU Reset
Resetting the MCU provides a way to start processing from a known set of initial conditions. During reset,
most control and status registers are forced to initial values and the program counter is loaded from the
reset vector ($FFFE:$FFFF). On-chip peripheral modules are disabled and I/O pins are initially configured
as general-purpose high-impedance inputs with pullup devices disabled. The I bit in the condition code
register (CCR) is set to block maskable interrupts until the user program has a chance to initialize the stack
pointer (SP) and system control settings. SP is forced to $00FF at reset.
Resets, Interrupts, and System Configuration
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
58 Freescale Semiconductor
The MC9S08RC/RD/RE/RG has these sources for reset:
• Power-on reset (POR)
• Low-voltage detect (LVD)
• Computer operating properly (COP) timer
• Illegal opcode detect
• Illegal address (16K and 8K devices only)
• Background debug forced reset
• The reset pin (RESET)
Each of these sources, with the exception of the background debug forced reset, has an associated bit in
the system reset status register. Whenever the MCU enters reset, the reset pin is driven low for 34 internal
bus cycles where the internal bus frequency is one-half the OSC frequency. After the 34 cycles are
completed, the pin is released and will be pulled up by the internal pullup resistor, unless it is held low
externally. After the pin is released, it is sampled after another 38 cycles to determine whether the reset pin
is the cause of the MCU reset.
5.4 Computer Operating Properly (COP) Watchdog
The COP watchdog is intended to force a system reset when the application software fails to execute as
expected. To prevent a system reset from the COP timer (when it is enabled), application software must
reset the COP timer periodically. If the application program gets lost and fails to reset the COP before it
times out, a system reset is generated to force the system back to a known starting point. The COP
watchdog is enabled by the COPE bit in SOPT (see Section 5.8.4, “System Options Register (SOPT),” for
additional information). The COP timer is reset by writing any value to the address of SRS. This write does
not affect the data in the read-only SRS. Instead, the act of writing to this address is decoded and sends a
reset signal to the COP timer.
After any reset, the COP timer is enabled. This provides a reliable way to detect code that is not executing
as intended. If the COP watchdog is not used in an application, it can be disabled by clearing the COPE
bit in the write-once SOPT register. Also, the COPT bit can be used to choose one of two timeout periods
(218 or 220 cycles of the bus rate clock). Even if the application will use the reset default settings in COPE
and COPT, the user must write to write-once SOPT during reset initialization to lock in the settings. That
way, they cannot be changed accidentally if the application program gets lost.
The write to SRS that services (clears) the COP timer must not be placed in an interrupt service routine
(ISR) because the ISR could continue to be executed periodically even if the main application program
fails.
When the MCU is in active background mode, the COP timer is temporarily disabled.
5.5 Interrupts
Interrupts provide a way to save the current CPU status and registers, execute an interrupt service routine
(ISR), and then restore the CPU status so processing resumes where it was before the interrupt. Other than
the software interrupt (SWI), which is a program instruction, interrupts are caused by hardware events such
Resets, Interrupts, and System Configuration
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 59
as an edge on the IRQ pin or a timer-overflow event. The debug module can also generate an SWI under
certain circumstances.
If an event occurs in an enabled interrupt source, an associated read-only status flag will become set. The
CPU will not respond until and unless the local interrupt enable is a logic 1 to enable the interrupt. The I
bit in the CCR is logic 0 to allow interrupts. The global interrupt mask (I bit) in the CCR is initially set
after reset, which masks (prevents) all maskable interrupt sources. The user program initializes the stack
pointer and performs other system setup before clearing the I bit to allow the CPU to respond to interrupts.
When the CPU receives a qualified interrupt request, it completes the current instruction before responding
to the interrupt. The interrupt sequence uses the same cycle-by-cycle sequence as the SWI instruction and
consists of:
• Saving the CPU registers on the stack
• Setting the I bit in the CCR to mask further interrupts
• Fetching the interrupt vector for the highest-priority interrupt that is currently pending
• Filling the instruction queue with the first three bytes of program information starting from the
address fetched from the interrupt vector locations
While the CPU is responding to the interrupt, the I bit is automatically set to avoid the possibility of another
interrupt interrupting the ISR itself (this is called nesting of interrupts). Normally, the I bit is restored to 0
when the CCR is restored from the value stacked on entry to the ISR. In rare cases, the I bit may be cleared
inside an ISR (after clearing the status flag that generated the interrupt) so that other interrupts can be
serviced without waiting for the first service routine to finish. This practice is not recommended for anyone
other than the most experienced programmers because it can lead to subtle program errors that are difficult
to debug.
The interrupt service routine ends with a return-from-interrupt (RTI) instruction that restores the CCR, A,
X, and PC registers to their pre-interrupt values by reading the previously saved information off the stack.
NOTE
For compatibility with the M68HC08 Family, the H register is not
automatically saved and restored. It is good programming practice to push
H onto the stack at the start of the interrupt service routine (ISR) and restore
it just before the RTI that is used to return from the ISR.
If two or more interrupts are pending when the I bit is cleared, the highest priority source is serviced first
(see Table 5-1).
5.5.1 Interrupt Stack Frame
Figure 5-1 shows the contents and organization of a stack frame. Before the interrupt, the stack pointer
(SP) points at the next available byte location on the stack. The current values of CPU registers are stored
on the stack starting with the low-order byte of the program counter (PCL) and ending with the CCR. After
stacking, the SP points at the next available location on the stack, which is the address that is one less than
the address where the CCR was saved. The PC value that is stacked is the address of the instruction in the
main program that would have executed next if the interrupt had not occurred.
Resets, Interrupts, and System Configuration
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
60 Freescale Semiconductor
Figure 5-1. Interrupt Stack Frame
When an RTI instruction is executed, these values are recovered from the stack in reverse order. As part of
the RTI sequence, the CPU fills the instruction pipeline by reading three bytes of program information,
starting from the PC address just recovered from the stack.
The status flag causing the interrupt must be acknowledged (cleared) before returning from the ISR.
Typically, the flag must be cleared at the beginning of the ISR so that if another interrupt is generated by
this same source, it will be registered so it can be serviced after completion of the current ISR.
5.5.2 External Interrupt Request (IRQ) Pin
External interrupts are managed by the IRQSC status and control register. When the IRQ function is
enabled, synchronous logic monitors the pin for edge-only or edge-and-level events. When the MCU is in
stop mode and system clocks are shut down, a separate asynchronous path is used so the IRQ (if enabled)
can wake the MCU.
5.5.2.1 Pin Configuration Options
The IRQ pin enable (IRQPE) control bit in the IRQSC register must be 1 in order for the IRQ pin to act as
the interrupt request (IRQ) input. When the pin is configured as an IRQ input, the user can choose the
polarity of edges or levels detected (IRQEDG), whether the pin detects edges-only or edges and levels
(IRQMOD), and whether an event causes an interrupt or merely sets the IRQF flag (which can be polled
by software).
When the IRQ pin is configured to detect rising edges, an optional pulldown resistor is available rather than
a pullup resistor. BIH and BIL instructions may be used to detect the level on the IRQ pin when the pin is
configured to act as the IRQ input.
CONDITION CODE REGISTER
ACCUMULATOR
INDEX REGISTER (LOW BYTE X)
PROGRAM COUNTER HIGH
* High byte (H) of index register is not automatically stacked.
*
PROGRAM COUNTER LOW
70
UNSTACKING
ORDER
STACKING
ORDER
5
4
3
2
1
1
2
3
4
5
TOWARD LOWER ADDRESSES
TOWARD HIGHER ADDRESSES
SP BEFORE
SP AFTER
INTERRUPT STACKING
THE INTERRUPT
Resets, Interrupts, and System Configuration
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 61
5.5.2.2 Edge and Level Sensitivity
The IRQMOD control bit reconfigures the detection logic so it detects edge events and pin levels. In this
edge detection mode, the IRQF status flag becomes set when an edge is detected (when the IRQ pin
changes from the deasserted to the asserted level), but the flag is continuously set (and cannot be cleared)
as long as the IRQ pin remains at the asserted level.
5.5.3 Interrupt Vectors, Sources, and Local Masks
Table 5-1 provides a summary of all interrupt sources. Higher-priority sources are located towards the
bottom of the table. The high-order byte of the address for the interrupt service routine is located at the
first address in the vector address column, and the low-order byte of the address for the interrupt service
routine is located at the next higher address.
When an interrupt condition occurs, an associated flag bit becomes set. If the associated local interrupt
enable is 1, an interrupt request is sent to the CPU. Within the CPU, if the global interrupt mask (I bit in
the CCR) is 0, the CPU will finish the current instruction; stack the PCL, PCH, X, A, and CCR CPU
registers; set the I bit; and then fetch the interrupt vector for the highest priority pending interrupt.
Processing then continues in the interrupt service routine.
Resets, Interrupts, and System Configuration
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
62 Freescale Semiconductor
5.6 Low-Voltage Detect (LVD) System
The MC9S08RC/RD/RE/RG includes a system to protect against low-voltage conditions in order to
protect memory contents and control MCU system states during supply voltage variations. The system is
comprised of a power-on reset (POR) circuit, an LVD circuit with flag bits for warning and detection, and
a mechanism for entering a system safe state following an LVD interrupt. The LVD circuit can be
configured to generate an interrupt or a reset when low supply voltage has been detected.
Table 5-1. Vector Summary
Vector
Priority
Vector
Number
Address
(High/Low) Vector Name Module Source Enable Description
Lower
Higher
16
through
31
$FFC0/FFC1
through
$FFDE/FFDF
Unused Vector Space
(available for user program)
15 $FFE0/FFE1 Vspi1 SPI(1)
1. The SPI module is not included on the MC9S08RC/RD/RE devices. This vector location is unused for those devices.
SPIF
MODF
SPTEF
SPIE
SPIE
SPTIE
SPI
14 $FFE2/FFE3 Vrti System
control RTIF RTIE Real-time interrupt
13 $FFE4/FFE5 Vkeyboard2 KBI2 KBF KBIE Keyboard 2 pins
12 $FFE6/FFE7 Vkeyboard1 KBI1 KBF KBIE Keyboard 1 pins
11 $FFE8/FFE9 Vacmp1 ACMP(2)
2. The analog comparator (ACMP) module is not included on the MC9S08RD devices. This vector location is unused for those
devices.
ACF ACIE ACMP compare
10 $FFEA/FFEB Vcmt CMT EOCF EOCIE CMT
9 $FFEC/FFED Vsci1tx SCI(3)
3. The SCI module is not included on the MC9S08RC devices. This vector location is unused for those devices.
TDRE
TC
TIE
TCIE SCI transmit
8 $FFEE/FFEF Vsci1rx SCI(3) IDLE
RDRF
ILIE
RIE SCI receive
7 $FFF0/FFF1 Vsci1err SCI(3)
OR
NF
FE
PF
ORIE
NFIE
FEIE
PFIE
SCI error
6 $FFF2/FFF3 Vtpm1ovf TPM TOF TOIE TPM overflow
5 $FFF4/FFF5 Vtpm1ch1 TPM CH1F CH1IE TPM channel 1
4 $FFF6/FFF7 Vtpm1ch0 TPM CH0F CH0IE TPM channel 0
3 $FFF8/FFF9 Virq IRQ IRQF IRQIE IRQ pin
2 $FFFA/FFFB Vlvd System
control LVDF LVDIE Low-voltage detect
1 $FFFC/FFFD Vswi Core SWI
Instruction — Software interrupt
0 $FFFE/FFFF Vreset System
control
COP
LVD
RESET pin
Illegal opcode
Illegal address
COPE
LVDRE
RSTPE
—
—
Watchdog timer
Low-voltage detect
External pin
Illegal opcode
Illegal address
Resets, Interrupts, and System Configuration
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 63
5.6.1 Power-On Reset Operation
When power is initially applied to the MCU, or when the supply voltage drops below the VPOR level, the
POR circuit will cause a reset condition. As the supply voltage rises, the LVD circuit will hold the chip in
reset until the supply has risen above the VLV D level. Both the POR bit and the LVD bit in SRS are set
following a POR.
5.6.2 LVD Reset Operation
The LVD can be configured to generate a reset upon detection of a low voltage condition. This is done by
setting LVDRE to 1. LVDRE is a write-once bit that is set following a POR and is unaffected by other
resets. When LVDRE = 1, setting the SAFE bit has no effect. After an LVD reset has occurred, the LVD
system will hold the MCU in reset until the supply voltage is above the VLVD level. The LVD bit in the
SRS register is set following either an LVD reset or POR.
5.6.3 LVD Interrupt and Safe State Operation
When the voltage on the supply pin VDD drops below VLVD and the LVD circuit is configured for interrupt
operation (LVDIE is set and LVDRE is clear), an LVD interrupt will occur. The LVD trip point is set above
the minimum voltage at which the MCU can reliably operate, but the supply voltage may still be dropping.
It is recommended that the user place the MCU in the safe state as soon as possible following a LVD
interrupt. For systems where the supply voltage may drop so rapidly that the MCU may not have time to
service the LVD interrupt and enter the safe state, it is recommended that the LVD be configured to
generate a reset. The safe state is entered by executing a STOP instruction with the SAFE bit in the system
power management status and control 1 (SPMSC1) register set while in a low voltage condition
(LVDF = 1).
After the LVD interrupt has occurred, the user may configure the system to block all interrupts, resets, or
wakeups by writing a 1 to the SAFE bit. While SAFE =1 and VDD is below VREARM all interrupts, resets,
and wakeups are blocked. After VDD is above VREARM, the SAFE bit is ignored (the SAFE bit will still
read a 1). After setting the SAFE bit, the MCU must be put into either the stop3 or stop2 mode before the
supply voltage drops below the minimum operating voltage of the MCU. The supply voltage may now
drop to a level just above the POR trip point and then restored to a level above VREARM and the MCU state
(in the case of stop3) and RAM contents will be preserved. When the supply voltage has been restored,
interrupts, resets, and wakeups are then unblocked. When the MCU has recovered from stop mode, the
SAFE bit should be cleared.
5.6.4 Low-Voltage Warning (LVW)
The LVD system has a low-voltage warning flag to indicate to the user that the supply voltage is
approaching, but is still above, the low-voltage detect voltage. The LVW does not have an interrupt
associated with it. However, the FLASH memory cannot be reliably programmed or erased below the
VLVW level, so the status of the LVWF bit in the system power management status and control 2 (SPMSC2)
register must be checked before initiating any FLASH program or erase operation.
Resets, Interrupts, and System Configuration
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
64 Freescale Semiconductor
5.7 Real-Time Interrupt (RTI)
The real-time interrupt function can be used to generate periodic interrupts based on a multiple of the
source clock’s period. The RTI has two source clock choices, the external clock input or the RTI's own
internal clock. The RTI can be used in run, wait, stop2, and stop3 modes. It is not available in stop1 mode.
In run and wait modes, only the external clock can be used as the RTI’s clock source. In stop2 mode, only
the internal RTI clock can be used. In stop3, either the external clock or internal RTI clock can be used.
When using the external oscillator in stop3 mode, it must be enabled in stop (OSCSTEN = 1) and
configured for low bandwidth operation (RANGE = 0).
The SRTISC register includes a read-only status flag, a write-only acknowledge bit, and a 3-bit control
value (RTIS2:RTIS1:RTIS0) used to select one of seven RTI periods. The RTI has a local interrupt enable,
RTIE, to allow masking of the real-time interrupt. The module can be disabled by writing 0:0:0 to
RTIS2:RTIS1:RTIS0 in which case the clock source input is disabled and no interrupts will be generated.
See Section 5.8.6, “System Real-Time Interrupt Status and Control Register (SRTISC),” for detailed
information about this register.
5.8 Reset, Interrupt, and System Control Registers and Control Bits
One 8-bit register in the direct page register space and five 8-bit registers in the high-page register space
are related to reset and interrupt systems.
Refer to the direct-page register summary in the Memory chapter of this data sheet for the absolute address
assignments for all registers. This section refers to registers and control bits only by their names. A
Freescale-provided equate or header file is used to translate these names into the appropriate absolute
addresses.
Some control bits in the SOPT and SPMSC2 registers are related to modes of operation. Although brief
descriptions of these bits are provided here, the related functions are discussed in greater detail in
Chapter 3, “Modes of Operation.”
5.8.1 Interrupt Pin Request Status and Control Register (IRQSC)
This direct page register includes two unimplemented bits that always read 0, four read/write bits, one
read-only status bit, and one write-only bit. These bits are used to configure the IRQ function, report status,
and acknowledge IRQ events.
Resets, Interrupts, and System Configuration
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 65
5.8.2 System Reset Status Register (SRS)
This register includes six read-only status flags to indicate the source of the most recent reset. When a
debug host forces reset by writing 1 to BDFR in the SBDFR register, none of the status bits in SRS will be
set. Writing any value to this register address clears the COP watchdog timer without affecting the contents
of this register. The reset state of these bits depends on what caused the MCU to reset.
76543210
R00
IRQEDG IRQPE
IRQF 0
IRQIE IRQMOD
WIRQACK
Reset 00000000
= Unimplemented or Reserved
Figure 5-2. Interrupt Request Status and Control Register (IRQSC)
Table 5-2. IRQSC Field Descriptions
Field Description
5
IRQEDG
Interrupt Request (IRQ) Edge Select — This read/write control bit is used to select the polarity of edges or
levels on the IRQ pin that cause IRQF to be set. The IRQMOD control bit determines whether the IRQ pin is
sensitive to both edges and levels or only edges. When the IRQ pin is enabled as the IRQ input and is configured
to detect rising edges, the optional pullup resistor is reconfigured as an optional pulldown resistor.
0 IRQ is falling edge or falling edge/low-level sensitive.
1 IRQ is rising edge or rising edge/high-level sensitive.
4
IRQPE
IRQ Pin Enable — This read/write control bit enables the IRQ pin function. When this bit is set the IRQ pin can
be used as an interrupt request. Also, when this bit is set, either an internal pull-up or an internal pull-down
resistor is enabled depending on the state of the IRQMOD bit.
0 IRQ pin function is disabled.
1 IRQ pin function is enabled.
3
IRQF
IRQ Flag — This read-only status bit indicates when an interrupt request event has occurred.
0 No IRQ request.
1 IRQ event detected.
2
IRQACK
IRQ Acknowledge — This write-only bit is used to acknowledge interrupt request events (write 1 to clear IRQF).
Writing 0 has no meaning or effect. Reads always return 0. If edge-and-level detection is selected
(IRQMOD = 1), IRQF cannot be cleared while the IRQ pin remains at its asserted level.
1
IRQIE
IRQ Interrupt Enable — This read/write control bit determines whether IRQ events generate a hardware
interrupt request.
0 Hardware interrupt requests from IRQF disabled (use polling).
1 Hardware interrupt requested whenever IRQF = 1.
0
IRQMOD
IRQ Detection Mode — This read/write control bit selects either edge-only detection or edge-and-level
detection. The IRQEDG control bit determines the polarity of edges and levels that are detected as interrupt
request events. See Section 5.5.2.2, “Edge and Level Sensitivity,” for more details.
0 IRQ event on falling edges or rising edges only.
1 IRQ event on falling edges and low levels or on rising edges and high levels.
Resets, Interrupts, and System Configuration
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
66 Freescale Semiconductor
76543210
RPOR PIN COP ILOP ILAD(1)
1. The ILAD bit is only present in 16K and 8K versions of the devices.
0LVD 0
W Writing any value to SRS address clears COP watchdog timer.
POR10000010
LVRu0000010
Any other
reset:
0(2)
2. Any of these reset sources that are active at the time of reset will cause the corresponding bit(s) to be set; bits corresponding
to sources that are not active at the time of reset will be cleared.
(2) (2) (2) 000
u = Unaffected by reset
Figure 5-3. System Reset Status (SRS)
Table 5-3. SRS Field Descriptions
Field Description
7
POR
Power-On Reset — Reset was caused by the power-on detection logic. Because the internal supply voltage was
ramping up at the time, the low-voltage reset (LVR) status bit is also set to indicate that the reset occurred while
the internal supply was below the LVR threshold.
0 Reset not caused by POR.
1 POR caused reset.
6
PIN
External Reset Pin — Reset was caused by an active-low level on the external reset pin.
0 Reset not caused by external reset pin.
1 Reset came from external reset pin.
5
COP
Computer Operating Properly (COP) Watchdog — Reset was caused by the COP watchdog timer timing out.
This reset source may be blocked by COPE = 0.
0 Reset not caused by COP timeout.
1 Reset caused by COP timeout.
4
ILOP
Illegal Opcode — Reset was caused by an attempt to execute an unimplemented or illegal opcode. The STOP
instruction is considered illegal if stop is disabled by STOPE = 0 in the SOPT register. The BGND instruction is
considered illegal if active background mode is disabled by ENBDM = 0 in the BDCSC register.
0 Reset not caused by an illegal opcode.
1 Reset caused by an illegal opcode.
3
ILAD
Illegal Address Access — Reset was caused by an attempt to access a designated illegal address.
0 Reset not caused by an illegal address access
1 Reset caused by an illegal address access
Illegal address areas only exist in the 16K and 8K versions and are defined as:
• $0440–$17FF — Gap from end of RAM to start of high-page registers
• $1834–$BFFF — Gap from end of high-page registers to start of FLASH memory
Unused and reserved locations in register areas are not considered designated illegal addresses and do not
trigger illegal address resets.
1
LVD
Low Voltage Detect — If the LVDRE bit is set and the supply drops below the LVD trip voltage, an LVD reset
occurs. This bit is also set by POR.
0 Reset not caused by LVD trip or POR
1 Reset caused by LVD trip or POR
Resets, Interrupts, and System Configuration
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 67
5.8.3 System Background Debug Force Reset Register (SBDFR)
This register contains a single write-only control bit. A serial background command such as
WRITE_BYTE must be used to write to SBDFR. Attempts to write this register from a user program are
ignored. Reads always return $00.
76543210
R00000000
WBDFR(1)
1. BDFR is writable only through serial background debug commands, not from user programs.
Reset 00000000
= Unimplemented or Reserved
Figure 5-4. System Background Debug Force Reset Register (SBDFR)
Table 5-4. SBDFR Field Descriptions
Field Description
0
BDFR
Background Debug Force Reset — A serial background command such as WRITE_BYTE may be used to
allow an external debug host to force a target system reset. Writing 1 to this bit forces an MCU reset. This bit
cannot be written from a user program.
Resets, Interrupts, and System Configuration
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
68 Freescale Semiconductor
5.8.4 System Options Register (SOPT)
This register may be read at any time. Bits 3 and 2 are unimplemented and always read 0. This is a
write-once register so only the first write after reset is honored. Any subsequent attempt to write to SOPT
(intentionally or unintentionally) is ignored to avoid accidental changes to these sensitive settings. SOPT
must be written during the user’s reset initialization program to set the desired controls even if the desired
settings are the same as the reset settings.
76543210
R
COPE COPT STOPE
00
BKGDPE RSTPE
W
Reset 11010011
= Unimplemented or Reserved
Figure 5-5. System Options Register (SOPT)
Table 5-5. SOPT Field Descriptions
Field Description
7
COPE
COP Watchdog Enable — This write-once bit defaults to 1 after reset.
0 COP watchdog timer disabled.
1 COP watchdog timer enabled (force reset on timeout).
6
COPT
COP Watchdog Timeout — This write-once bit defaults to 1 after reset.
0 Short timeout period selected (218 cycles of BUSCLK).
1 Long timeout period selected (220 cycles of BUSCLK).
5
STOPE
Stop Mode Enable — This write-once bit defaults to 0 after reset, which disables stop mode. If stop mode is
disabled and a user program attempts to execute a STOP instruction, an illegal opcode reset is forced.
0 Stop mode disabled.
1 Stop mode enabled.
1
BKGDPE
Background Debug Mode Pin Enable — The BKGDPE bit enables the PTD0/BKGD/MS pin to function as
BKGD/MS. When the bit is clear, the pin will function as PTD0, which is an output only general purpose I/O. This
pin always defaults to BKGD/MS function after any reset.
0 BKGD pin disabled.
1 BKGD pin enabled.
0
RSTPE
RESET Pin Enable — The RSTPE bit enables the PTD1/RESET pin to function as RESET. When the bit is clear,
the pin will function as PTD1, which is an output only general purpose I/O. This pin always defaults to RESET
function after any reset.
0RESET pin disabled.
1RESET pin enabled.
Resets, Interrupts, and System Configuration
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 69
5.8.5 System Device Identification Register (SDIDH, SDIDL)
This read-only register is included so host development systems can identify the HCS08 derivative and
revision number. This allows the development software to recognize where specific memory blocks,
registers, and control bits are located in a target MCU.
76543210
RREV3 REV2 REV1 REV0 ID11 ID10 ID9 ID8
W
Reset 0(1)
1. The revision number that is hard coded into these bits reflects the current silicon revision level.
0(1) 0(1) 0(1) 0000
= Unimplemented or Reserved
Figure 5-6. System Device Identification Register — High (SDIDH)
Table 5-6. SDIDH Field Descriptions
Field Description
7:4
REV[3:0]
Revision Number — The high-order 4 bits of address $1806 are hard coded to reflect the current mask set
revision number (0–F).
3:0
ID[11:8]
Part Identification Number — Each derivative in the HCS08 Family has a unique identification number. The
MC9S08RC/RD/RE/RG32/60 is hard coded to the value $004 and the MC9S08RC/RD/RE8/16 is hard coded to
the value $003.
76543210
RID7 ID6 ID5 ID4 ID3 ID2 ID1 ID0
W
Reset, 8/16K: 00000111
Reset, 32/60K: 00000100
= Unimplemented or Reserved
Figure 5-7. System Device Identification Register — Low (SDIDL)
Table 5-7. SDIDL Field Descriptions
Field Description
7:0
ID[7:0]
Part Identification Number — Each derivative in the HCS08 Family has a unique identification number. The
MC9S08RC/RD/RE/RG32/60 is hard coded to the value $004 and the MC9S08RC/RD/RE8/16 is hard coded to
the value $003.
Resets, Interrupts, and System Configuration
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
70 Freescale Semiconductor
5.8.6 System Real-Time Interrupt Status and Control Register (SRTISC)
This register contains one read-only status flag, one write-only acknowledge bit, three read/write delay
selects, and three unimplemented bits, which always read 0.
76543210
R RTIF 0
RTICLKS RTIE
0
RTIS2 RTIS1 RTIS0
W RTIACK
Reset 00000000
= Unimplemented or Reserved
Figure 5-8. System RTI Status and Control Register (SRTISC)
Table 5-8. SRTISC Field Descriptions
Field Description
7
RTIF
Real-Time Interrupt Flag — This read-only status bit indicates the periodic wakeup timer has timed out.
0 Periodic wakeup timer not timed out.
1 Periodic wakeup timer timed out.
6
RTIACK
Real-Time Interrupt Acknowledge — This write-only bit is used to acknowledge real-time interrupt request
(write 1 to clear RTIF). Writing 0 has no meaning or effect. Reads always return 0.
5
RTICLKS
Real-Time Interrupt Clock Select — This read/write bit selects the clock source for the real-time interrupt.
0 Real-time interrupt request clock source is internal 1-kHz oscillator.
1 Real-time interrupt request clock source is external clock.
4
RTIE
Real-Time Interrupt Enable — This read-write bit enables real-time interrupts.
0 Real-time interrupts disabled.
1 Real-time interrupts enabled.
2:0
RTIS[2:0]
Real-Time Interrupt Period Selects — These read/write bits select the wakeup period for the RTI. One clock
source for the real-time interrupt is its own internal clock source, which oscillates with a period of approximately
tRTI and is independent of other MCU clock sources. Using an external clock source the delays will be crystal
frequency divided by value in RTIS2:RTIS1:RTIS0. See Table 5-9.
Table 5-9. Real-Time Interrupt Period
RTIS2:RTIS1:RTIS0 Internal Clock Source (1)
(tRTI = 1 ms, Nominal)
1. See Table A-9 tRTI in Appendix A, “Electrical Characteristics,” for the tolerance on these values.
External Clock Source (2)
Period = text
2. text is based on the external clock source, resonator, or crystal selected by the ICG configuration. See Table A-9 for details.
0:0:0 Disable periodic wakeup timer Disable periodic wakeup timer
0:0:1 8 ms text x 256
0:1:0 32 ms tex x 1024
0:1:1 64 ms tex x 2048
1:0:0 128 ms tex x 4096
1:0:1 256 ms text x 8192
1:1:0 512 ms text x 16384
1:1:1 1.024 s tex x 32768
Resets, Interrupts, and System Configuration
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 71
5.8.7 System Power Management Status and Control 1 Register
(SPMSC1)
76543210
R LVDF 0
LVDIE SAFE LVDRE(1)
1. This bit can be written only one time after reset. Additional writes are ignored.
000
WLVDACK
POR: 00001000
Any other
reset:
0000u000
= Unimplemented or Reserved u = Unaffected by reset
Figure 5-9. System Power Management Status and Control 1 Register (SPMSC1)
Table 5-10. SPMSC1 Field Descriptions
Field Description
7
LVDF
Low-Voltage Detect Flag — Provided LVDE = 1, this read-only status bit indicates a low-voltage detect error.
6
LVDACK
Low-Voltage Detect Acknowledge — This write-only bit is used to acknowledge low voltage detection errors
(write 1 to clear LVDF). Reads always return logic 0.
5
LVDIE
Low-Voltage Detect Interrupt Enable — This read/write bit enables hardware interrupt requests for LVDF.
0 Hardware interrupt disabled (use polling).
1 Request a hardware interrupt when LVDF = 1.
4
SAFE
SAFE System from interrupts — This read/write bit enables hardware to block interrupts and resets from
waking the MCU from stop mode while the supply voltage VDD is below the VREARM voltage. For a more detailed
description see Section 5.6.3, “LVD Interrupt and Safe State Operation”
0 Enable pending interrupts and resets
1 Interrupts and resets are blocked while supply voltage is below re-arm voltage
3
LVDRE
Low-Voltage Detect Reset Enable — This bit enables the LVD reset function. This bit can be written only once
after a reset and additional writes have no meaning or effect. It is set following a POR and is unaffected by any
other resets, including an LVD reset.
0 LVDF does not generate hardware resets.
1 Force an MCU reset when LVDF = 1.
Resets, Interrupts, and System Configuration
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
72 Freescale Semiconductor
5.8.8 System Power Management Status and Control 2 Register
(SPMSC2)
This register is used to report the status of the low voltage warning function, and to configure the stop mode
behavior of the MCU.
76543210
RLVWF 0 0 0 PPDF 0
PDC PPDC
WLVWACK PPDACK
Reset 0(1)
1. LVWF will be set in the case when VSupply transitions below the trip point or after reset and VSupply is already below VLVW.
0000000
= Unimplemented or Reserved
Figure 5-10. System Power Management Status and Control 2 Register (SPMSC2)
Table 5-11. SPMSC2 Field Descriptions
Field Description
7
LVWF
Low-Voltage Warning Flag — The LVWF bit indicates the low voltage warning status.
0 Low voltage warning not present.
1 Low voltage warning is present or was present.
6
LVWAC K
Low-Voltage Warning Acknowledge — The LVWF bit indicates the low voltage warning status. Writing a 1 to
LVWACK clears LVWF to a 0 if a low voltage warning is not present.
3
PPDF
Partial Power Down Flag — The PPDF bit indicates that the MCU has exited the stop2 mode.
0 Not stop2 mode recovery.
1 Stop2 mode recovery.
2
PPDACK
Partial Power Down Acknowledge — Writing a logic 1 to PPDACK clears the PPDF bit.
1
PDC
Power Down Control — The write-once PDC bit controls entry into the power down (stop2 and stop1) modes.
0 Power down modes are disabled.
1 Power down modes are enabled.
0
PPDC
Partial Power Down Control — The write-once PPDC bit controls which power down mode, stop1 or stop2, is
selected.
0 Stop1, full power down, mode enabled if PDC set.
1 Stop2, partial power down, mode enabled if PDC set.
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 73
Chapter 6
Parallel Input/Output
6.1 Introduction
This section explains software controls related to parallel input/output (I/O). The MC9S08RC/RD/RE/RG
has five I/O ports that include a total of 39 general-purpose I/O pins (two of these pins are output only and
one pin is input only). Not all of the ports are available in all packages. See Chapter 2, “Pins and
Connections,” for more information about the logic and hardware aspects of these pins.
Many of these pins are shared with on-chip peripherals such as timer systems, external interrupts, or
keyboard interrupts. When these other modules are not controlling the port pins, they revert to
general-purpose I/O control. For each I/O pin, a port data bit provides access to input (read) and output
(write) data. A data direction bit controls the direction of the pin and a pullup enable bit enables an internal
pullup device (if the pin is configured as an input).
NOTE
Not all general-purpose I/O pins are available on all packages. To avoid
extra current drain from floating input pins, the user’s reset initialization
routine in the application program should either enable on-chip pullup
devices or change the direction of unconnected pins to outputs so the pins
do not float.
6.2 Features
Parallel I/O features for the MC9S08RC/RD/RE/RG MCUs, depending on specific device and package
choice, include:
• A total of 39 general-purpose I/O pins in five ports (two pins are output only, one is input only)
• High-current drivers on port B pins
• Hysteresis input buffers on all inputs
• Software-controlled pullups on each input pin
• Eight port A pins shared with KBI1
• Eight port B pins shared with SCI and TPMCH1
• Eight port C pins shared with KBI2 and SPI
• Seven port D pins shared with TPMCH0, ACMP, IRQ, RESET, and BKGD/MS
• Eight port E pins
Parallel Input/Output
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
74 Freescale Semiconductor
6.3 Pin Descriptions
The MC9S08RC/RD/RE/RG has a total of 39 parallel I/O pins distributed between four 8-bit ports and one
7-bit port. Not all pins are bonded out in all packages. Consult the pin assignment in Chapter 2, “Pins and
Connections,” for available parallel I/O pins. All of these pins are available for general-purpose I/O when
they are not used by other on-chip peripheral systems.
The following paragraphs discuss each port and the software controls that determine each pin’s use.
6.3.1 Port A
Figure 6-1. Port A Pin Names
Port A is an 8-bit general-purpose I/O port shared with the KBI1 keyboard interrupt inputs. Bit 0 of port
A is an input-only pin.
Port A pins are available as general-purpose I/O pins controlled by the port A data (PTAD), data direction
(PTADD), and pullup enable (PTAPE) registers. Refer to Section 6.4, “Parallel I/O Controls,” for more
information about general-purpose I/O control.
Any of the port A pins can be configured as a KBI1 keyboard interrupt pin. Refer to the Keyboard Interrupt
(KBI) Module chapter for more information about using port A pins as keyboard interrupt pins.
6.3.2 Port B
Figure 6-2. Port B Pin Names
Port B is an 8-bit general-purpose I/O port with two pins shared with the SCI and one pin shared with the
TPM. The port B output drivers are capable of high current drive.
Port B pins are available as general-purpose I/O pins controlled by the port B data (PTBD), data direction
(PTBDD), and pullup enable (PTBPE) registers. Refer to Section 6.4, “Parallel I/O Controls,” for more
information about general-purpose I/O control.
When the SCI module is enabled, PTB0 and PTB1 function as the transmit (TxD1) and receive (RxD1)
pins of the SCI. Refer to the Serial Communications Interface (SCI) Module chapter for more information
about using PTB0 and PTB1 as SCI pins.
The TPM can be configured to use PTB7 as either an input capture, output compare, or PWM pin. Refer
to the Timer/PWM Module (TPM) Module chapter for more information about using PTB7 as a timer pin.
Port A Bit 7 654321Bit 0
MCU Pin: PTA7/
KBI1P7
PTA6/
KBI1P6
PTA5/
KBI1P5
PTA4/
KBI1P4
PTA3/
KBI1P3
PTA2/
KBI1P2
PTA1/
KBI1P1
PTA0/
KBI1P0
Port B Bit 7 654321Bit 0
MCU Pin: PTB7/
TPM1CH1 PTB6 PTB5 PTB4 PTB3 PTB2 PTB1/
RxD1
PTB0/
TxD1
Parallel Input/Output
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 75
6.3.3 Port C
Figure 6-3. Port C Pin Names
Port C is an 8-bit general-purpose I/O port with four pins shared with the KBI2 keyboard interrupt inputs
and four pins shared with the SPI.
Port C pins are available as general-purpose I/O pins controlled by the port C data (PTCD), data direction
(PTCDD), and pullup enable (PTCPE) registers. Refer to Section 6.4, “Parallel I/O Controls,” for more
information about general-purpose I/O control.
When the SPI module is enabled, PTC7 serves as the SPI module’s slave select pin (SS1), PTC6 serves as
the SPI clock pin (SPSCK1), PTC5 serves as the master-in slave-out pin (MISO1), and PTC4 serves as the
master-out slave-in pin (MOSI1). Refer to the Serial Peripheral Interface (SPI) Module chapter for more
information about using PTC7–PTC4 as SPI pins.
Any of the port C pins PTC3-PTC0 can be configured as a KBI2 keyboard interrupt pin. Refer to the
Keyboard Interrupt (KBI) Module chapter for more information about using port C pins as keyboard
interrupt pins.
6.3.4 Port D
Figure 6-4. Port D Pin Names
Port D is an 7-bit general-purpose I/O port with one pin shared with the BKGD/MS function, one pin
shared with the RESET function, one pin shared with the IRQ function, and one pin shared with the TPM.
Port D pins are available as general-purpose I/O pins controlled by the port D data (PTDD), data direction
(PTDDD), and pullup enable (PTDPE) registers. Refer to Section 6.4, “Parallel I/O Controls,” for more
information about general-purpose I/O control.
The PTD0/BKGD/MS pin is configured for the BKGD/MS function during reset and following reset. The
internal pullup for this pin is enabled when the BKGD/MS function is enabled, regardless of the PTDPE0
bit. During reset, the BKGD/MS pin functions as a mode select pin. After the MCU is out of reset, the
BKGD/MS pin becomes the background communications input/output pin. PTD0 can be configured to be
a general-purpose output pin through software control. Refer to Chapter 3, “Modes of Operation,”
Chapter 5, “Resets, Interrupts, and System Configuration,” and the Development Support chapter for more
information about using this pin.
The PTD1/RESET pin is configured for the RESET function during reset and following reset.
Port C Bit 7 653321Bit 0
MCU Pin: PTC7/
SS1
PTC6/
SPSCK1
PTC5/
MISO1
PTC4/
MOSI1
PTC3/
KBI2P3
PTC2/
KBI2P2
PTC1/
KBI2P1
PTC0/
KBI2P0
Port D Bit 7 6 54321Bit 0
MCU Pin: PTD6/
TPM1CH0 PTD5 PTD4 PTD3 PTD2 PTD1/
RESET
PTD0/
BKGD/MS
Parallel Input/Output
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
76 Freescale Semiconductor
The TPM can be configured to use PTD6 as either an input capture, output compare, PWM, or external
clock input pin. Refer to the Chapter 6, “Parallel Input/Output,” for more information about using PTD6
as a timer pin.
6.3.5 Port E
Figure 6-5. Port E Pin Names
Port E is an 8-bit general-purpose I/O port.
Port E pins are available as general-purpose I/O pins controlled by the port E data (PTED), data direction
(PTEDD), and pullup enable (PTEPE) registers. Refer to Section 6.4, “Parallel I/O Controls,” for more
information about general-purpose I/O control.
6.4 Parallel I/O Controls
Provided no on-chip peripheral is controlling a port pin, the pins operate as general-purpose I/O pins that
are accessed and controlled by a data register (PTxD), a data direction register (PTxDD), and a pullup
enable register (PTxPE) where x is A, B, C, D, or E.
Reads of the data register return the pin value (if PTxDDn = 0) or the contents of the port data register (if
PTxDDn = 1). Writes to the port data register are latched into the port register whether the pin is controlled
by an on-chip peripheral or the pin is configured as an input. If the corresponding pin is not controlled by
a peripheral and is configured as an output, this level will be driven out the port pin.
6.4.1 Data Direction Control
The data direction control bits determine whether the pin output driver is enabled, and they control what
is read for port data register reads. Each port pin has a data direction control bit. When PTxDDn = 0, the
corresponding pin is an input and reads of PTxD return the pin value. When PTxDDn = 1, the
corresponding pin is an output and reads of PTxD return the last value written to the port data register.
When a peripheral module or system function is in control of a port pin, the data direction control still
controls what is returned for reads of the port data register, even though the peripheral system has
overriding control of the actual pin direction.
For the MC9S08RC/RD/RE/RG MCU, reads of PTD0/BKGD/MS and PTD1/RESET will return the value
on the output pin.
It is a good programming practice to write to the port data register before changing the direction of a port
pin to become an output. This ensures that the pin will not be driven with an old data value that happened
to be in the port data register.
Port E Bit 7 654321Bit 0
MCU Pin: PTE7 PTE6 PTE5 PTE4 PTE3 PTE2 PTE1 PTE0
Parallel Input/Output
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 77
6.4.2 Internal Pullup Control
An internal pullup device can be enabled for each port pin that is configured as an input (PTxDDn = 0).
The pullup device is available for a peripheral module to use, provided the peripheral is enabled and is an
input function as long as the PTxDDn = 0.
NOTE
The voltage measured on the pulled up PTA0 pin will be less than VDD. The
internal gates connected to this pin are pulled all the way to VDD. All other
pins with enabled pullup resistors will have an unloaded measurement of
VDD.
6.5 Stop Modes
Depending on the stop mode, I/O functions differently as the result of executing a STOP instruction. An
explanation of I/O behavior for the various stop modes follows:
• When the MCU enters stop1 mode, all internal registers, including general-purpose I/O control and
data registers, are powered down. All of the general-purpose I/O pins assume their reset state:
output buffers and pullups turned off. Upon exit from stop1, all I/O must be initialized as if the
MCU had been reset.
• When the MCU enters stop2 mode, the internal registers are powered down as in stop1 but the I/O
pin states are latched and held. For example, a port pin that is an output driving low continues to
function as an output driving low even though its associated data direction and output data registers
are powered down internally. Upon exit from stop2, the pins continue to hold their states until a 1
is written to the PPDACK bit. To avoid discontinuity in the pin state following exit from stop2, the
user must restore the port control and data registers to the values they held befor4e entering stop2.
These values can be stored in RAM before entering stop2 because the RAM is maintained during
stop2.
• In stop3 mode, all I/O is maintained because internal logic circuity stays powered up. Upon
recovery, normal I/O function is available to the user.
6.6 Parallel I/O Registers and Control Bits
This section provides information about all registers and control bits associated with the parallel I/O ports.
Refer to tables in the Memory chapter for the absolute address assignments for all parallel I/O registers.
This section refers to registers and control bits only by their names. A Freescale-provided equate or header
file normally is used to translate these names into the appropriate absolute addresses.
Parallel Input/Output
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
78 Freescale Semiconductor
6.6.1 Port A Registers (PTAD, PTAPE, and PTADD)
Port A pins used as general-purpose I/O pins are controlled by the port A data (PTAD), data direction
(PTADD), and pullup enable (PTAPE) registers.
76543210
R
PTAD7 PTAD6 PTAD5 PTAD4 PTAD3 PTAD2 PTAD1 PTAD0
W
Reset 00000000
Figure 6-6. Port A Data Register (PTAD)
Table 6-1. PTAD Field Descriptions
Field Description
7:0
PTAD[7:0]
Port A Data Register Bits — For port A pins that are inputs, reads of this register return the logic level on the
pin. For port A pins that are configured as outputs, reads of this register return the last value written to this
register.
Writes are latched into all bits of this register. For port A pins that are configured as outputs, the logic level is
driven out the corresponding MCU pin.
Reset forces PTAD to all 0s, but these 0s are not driven out the corresponding pins because reset also configures
all port pins as high-impedance inputs with pullups disabled.
76543210
R
PTAPE7 PTAPE6 PTAPE5 PTAPE4 PTAPE3 PTAPE2 PTAPE1 PTAPE0
W
Reset 00000000
Figure 6-7. Pullup Enable for Port A (PTAPE)
Table 6-2. PTAPE Field Descriptions
Field Description
7:0
PTAPE[7:0]
Pullup Enable for Port A Bits — For port A pins that are inputs, these read/write control bits determine whether
internal pullup devices are enabled provided the corresponding PTADDn is a logic 0. For port A pins that are
configured as outputs, these bits are ignored and the internal pullup devices are disabled. When any of bits 7
through 4 of port A are enabled as KBI inputs and are configured to detect rising edges/high levels, the pullup
enable bits enable pulldown rather than pullup devices.
0 Internal pullup device disabled.
1 Internal pullup device enabled.
Parallel Input/Output
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 79
6.6.2 Port B Registers (PTBD, PTBPE, and PTBDD)
Port B pins used as general-purpose I/O pins are controlled by the port B data (PTBD), data direction
(PTBDD), and pullup enable (PTBPE) registers.
76543210
R
PTADD7 PTADD6 PTADD5 PTADD4 PTADD3 PTADD2 PTADD1 PTADD0
W
Reset 00000000
Figure 6-8. Data Direction for Port A (PTADD)
Table 6-3. PTADD Field Descriptions
Field Description
7:0
PTADD[7:0]
Data Direction for Port A Bits — These read/write bits control the direction of port A pins and what is read for
PTAD reads.
0 Input (output driver disabled) and reads return the pin value.
1 Output driver enabled for port A bit n and PTAD reads return the contents of PTADn.
76543210
R
PTBD7 PTBD6 PTBD5 PTBD4 PTBD3 PTBD2 PTBD1 PTBD0
W
Reset 00000000
Figure 6-9. Port B Data Register (PTBD)
Table 6-4. PTBD Field Descriptions
Field Description
7:0
PTBD[7:0]
Port B Data Register Bits — For port B pins that are inputs, reads return the logic level on the pin. For port B
pins that are configured as outputs, reads return the last value written to this register.
Writes are latched into all bits of this register. For port B pins that are configured as outputs, the logic level is
driven out the corresponding MCU pin.
Reset forces PTBD to all 0s, but these 0s are not driven out on the corresponding pins because reset also
configures all port pins as high-impedance inputs with pullups disabled.
Parallel Input/Output
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
80 Freescale Semiconductor
76543210
R
PTBPE7 PTBPE6 PTBPE5 PTBPE4 PTBPE3 PTBPE2 PTBPE1 PTBPE0
W
Reset 00000000
Figure 6-10. Pullup Enable for Port B (PTBPE)
Table 6-5. PTBPE Field Descriptions
Field Description
7:0
PTBPE[7:0]
Pullup Enable for Port B Bits — For port B pins that are inputs, these read/write control bits determine whether
internal pullup devices are enabled. For port B pins that are configured as outputs, these bits are ignored and
the internal pullup devices are disabled.
0 Internal pullup device disabled.
1 Internal pullup device enabled.
76543210
R
PTBDD7 PTBDD6 PTBDD5 PTBDD4 PTBDD3 PTBDD2 PTBDD1 PTBDD0
W
Reset 00000000
Figure 6-11. Data Direction for Port B (PTBDD)
Table 6-6. PTBDD Field Descriptions
Field Description
7:0
PTBDD[7:0]
Data Direction for Port B Bits — These read/write bits control the direction of port B pins and what is read for
PTBD reads.
0 Input (output driver disabled) and reads return the pin value.
1 Output driver enabled for port B bit n and PTBD reads return the contents of PTBDn.
Parallel Input/Output
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 81
6.6.3 Port C Registers (PTCD, PTCPE, and PTCDD)
Port C pins used as general-purpose I/O pins are controlled by the port C data (PTCD), data direction
(PTCDD), and pullup enable (PTCPE) registers.
76543210
R
PTCD7 PTCD6 PTCD5 PTCD4 PTCD3 PTCD2 PTCD1 PTCD0
W
Reset 00000000
Figure 6-12. Port C Data Register (PTCD)
Table 6-7. PTCD Field Descriptions
Field Description
7:0
PTCD[7:0]
Port C Data Register Bits — For port C pins that are inputs, reads return the logic level on the pin. For port C
pins that are configured as outputs, reads return the last value written to this register.
Writes are latched into all bits of this register. For port C pins that are configured as outputs, the logic level is
driven out the corresponding MCU pin.
Reset forces PTCD to all 0s, but these 0s are not driven out the corresponding pins because reset also
configures all port pins as high-impedance inputs with pullups disabled.
76543210
R
PTCPE7 PTCPE6 PTCPE5 PTCPE4 PTCPE3 PTCPE2 PTCPE1 PTCPE0
W
Reset 00000000
Figure 6-13. Pullup Enable for Port C (PTCPE)
Table 6-8. PTCPE Field Descriptions
Field Description
7:0
PTCPE[7:0]
Pullup Enable for Port C Bits — For port C pins that are inputs, these read/write control bits determine whether
internal pullup devices are enabled. For port C pins that are configured as outputs, these bits are ignored and
the internal pullup devices are disabled.
0 Internal pullup device disabled.
1 Internal pullup device enabled.
Parallel Input/Output
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
82 Freescale Semiconductor
6.6.4 Port D Registers (PTDD, PTDPE, and PTDDD)
Port D pins used as general-purpose I/O pins are controlled by the port D data (PTDD), data direction
(PTDDD), and pullup enable (PTDPE) registers.
76543210
R
PTCDD7 PTCDD6 PTCDD5 PTCDD4 PTCDD3 PTCDD2 PTCDD1 PTCDD0
W
Reset 00000000
Figure 6-14. Data Direction for Port C (PTCDD)
Table 6-9. PTCDD Field Descriptions
Field Description
7:0
PTCDD[7:0]
Data Direction for Port C Bits — These read/write bits control the direction of port C pins and what is read for
PTCD reads.
0 Input (output driver disabled) and reads return the pin value.
1 Output driver enabled for port C bit n and PTCD reads return the contents of PTCDn.
76543210
R0
PTDD6 PTDD5 PTDD4 PTDD3 PTDD2 PTDD1 PTDD0
W
Reset 00000000
= Unimplemented or Reserved
Figure 6-15. Port D Data Register (PTDD)
Table 6-10. PTDD Field Descriptions
Field Description
6:0
PTDD[6:0]
Port D Data Register Bits — For port D pins that are inputs, reads return the logic level on the pin. For port D
pins that are configured as outputs, reads return the last value written to this register.
Writes are latched into all bits of this register. For port D pins that are configured as outputs, the logic level is
driven out the corresponding MCU pin.
Reset forces PTDD to all 0s, but these 0s are not driven out the corresponding pins because reset also
configures all port pins as high-impedance inputs with pullups disabled.
Parallel Input/Output
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 83
76543210
R0
PTDPE6 PTDPE5 PTDPE4 PTDPE3 PTDPE2 PTDPE1 PTDPE0
W
Reset 00000000
= Unimplemented or Reserved
Figure 6-16. Pullup Enable for Port D (PTDPE)
Table 6-11. PTDPE Field Descriptions
Field Description
6:0
PTDPE[6:0]
Pullup Enable for Port D Bits — For port D pins that are inputs, these read/write control bits determine whether
internal pullup devices are enabled. For port D pins that are configured as outputs, these bits are ignored and
the internal pullup devices are disabled.
0 Internal pullup device disabled.
1 Internal pullup device enabled.
76543210
R0
PTDDD6 PTDDD5 PTDDD4 PTDDD3 PTDDD2 PTDDD1 PTDDD0
W
Reset 00000000
= Unimplemented or Reserved
Figure 6-17. Data Direction for Port D (PTDDD)
Table 6-12. PTDDD Field Descriptions
Field Description
6:0
PTDDD[6:0]
Data Direction for Port D Bits — These read/write bits control the direction of port D pins and what is read for
PTDD reads.
0 Input (output driver disabled) and reads return the pin value.
1 Output driver enabled for port D bit n and PTDD reads return the contents of PTDDn.
Parallel Input/Output
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
84 Freescale Semiconductor
6.6.5 Port E Registers (PTED, PTEPE, and PTEDD)
Port E pins used as general-purpose I/O pins are controlled by the port E data (PTED), data direction
(PTEDD), and pullup enable (PTEPE) registers.
76543210
R
PTED7 PTED6 PTED5 PTED4 PTED3 PTED2 PTED1 PTED0
W
Reset 00000000
Figure 6-18. Port E Data Register (PTED)
Table 6-13. PTED Field Descriptions
Field Description
7:0
PTED[7:0]
Port E Data Register Bits — For port E pins that are inputs, reads return the logic level on the pin. For port E
pins that are configured as outputs, reads return the last value written to this register.
Writes are latched into all bits of this register. For port E pins that are configured as outputs, the logic level is
driven out the corresponding MCU pin.
Reset forces PTED to all 0s, but these 0s are not driven out the corresponding pins because reset also configures
all port pins as high-impedance inputs with pullups disabled.
76543210
R
PTEPE7 PTEPE6 PTEPE5 PTEPE4 PTEPE3 PTEPE2 PTEPE1 PTEPE0
W
Reset 00000000
Figure 6-19. Pullup Enable for Port E (PTED)
Table 6-14. PTED Field Descriptions
Field Description
7:0
PTED[7:0]
Pullup Enable for Port E Bits — For port E pins that are inputs, these read/write control bits determine whether
internal pullup devices are enabled. For port E pins that are configured as outputs, these bits are ignored and
the internal pullup devices are disabled.
0 Internal pullup device disabled.
1 Internal pullup device enabled.
Parallel Input/Output
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 85
76543210
R
PTEDD7 PTEDD6 PTEDD5 PTEDD4 PTEDD3 PTEDD2 PTEDD1 PTEDD0
W
Reset 00000000
Figure 6-20. Data Direction for Port E (PTEDD)
Table 6-15. PTEDD Field Descriptions
Field Description
7:0
PTEDD[7:0]
Data Direction for Port E Bits — These read/write bits control the direction of port E pins and what is read for
PTED reads.
0 Input (output driver disabled) and reads return the pin value.
1 Output driver enabled for port E bit n and PTED reads return the contents of PTEDn.
Parallel Input/Output
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
86 Freescale Semiconductor
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 87
Chapter 7
Central Processor Unit (S08CPUV2)
7.1 Introduction
This section provides summary information about the registers, addressing modes, and instruction set of
the CPU of the HCS08 Family. For a more detailed discussion, refer to the HCS08 Family Reference
Manual, volume 1, Freescale Semiconductor document order number HCS08RMV1/D.
The HCS08 CPU is fully source- and object-code-compatible with the M68HC08 CPU. Several
instructions and enhanced addressing modes were added to improve C compiler efficiency and to support
a new background debug system which replaces the monitor mode of earlier M68HC08 microcontrollers
(MCU).
7.1.1 Features
Features of the HCS08 CPU include:
• Object code fully upward-compatible with M68HC05 and M68HC08 Families
• All registers and memory are mapped to a single 64-Kbyte address space
• 16-bit stack pointer (any size stack anywhere in 64-Kbyte address space)
• 16-bit index register (H:X) with powerful indexed addressing modes
• 8-bit accumulator (A)
• Many instructions treat X as a second general-purpose 8-bit register
• Seven addressing modes:
— Inherent — Operands in internal registers
— Relative — 8-bit signed offset to branch destination
— Immediate — Operand in next object code byte(s)
— Direct — Operand in memory at 0x0000–0x00FF
— Extended — Operand anywhere in 64-Kbyte address space
— Indexed relative to H:X — Five submodes including auto increment
— Indexed relative to SP — Improves C efficiency dramatically
• Memory-to-memory data move instructions with four address mode combinations
• Overflow, half-carry, negative, zero, and carry condition codes support conditional branching on
the results of signed, unsigned, and binary-coded decimal (BCD) operations
• Efficient bit manipulation instructions
• Fast 8-bit by 8-bit multiply and 16-bit by 8-bit divide instructions
• STOP and WAIT instructions to invoke low-power operating modes
Central Processor Unit (S08CPUV2)Central Processor Unit (S08CPUV2)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
88 Freescale Semiconductor
7.2 Programmer’s Model and CPU Registers
Figure 7-1 shows the five CPU registers. CPU registers are not part of the memory map.
Figure 7-1. CPU Registers
7.2.1 Accumulator (A)
The A accumulator is a general-purpose 8-bit register. One operand input to the arithmetic logic unit
(ALU) is connected to the accumulator and the ALU results are often stored into the A accumulator after
arithmetic and logical operations. The accumulator can be loaded from memory using various addressing
modes to specify the address where the loaded data comes from, or the contents of A can be stored to
memory using various addressing modes to specify the address where data from A will be stored.
Reset has no effect on the contents of the A accumulator.
7.2.2 Index Register (H:X)
This 16-bit register is actually two separate 8-bit registers (H and X), which often work together as a 16-bit
address pointer where H holds the upper byte of an address and X holds the lower byte of the address. All
indexed addressing mode instructions use the full 16-bit value in H:X as an index reference pointer;
however, for compatibility with the earlier M68HC05 Family, some instructions operate only on the
low-order 8-bit half (X).
Many instructions treat X as a second general-purpose 8-bit register that can be used to hold 8-bit data
values. X can be cleared, incremented, decremented, complemented, negated, shifted, or rotated. Transfer
instructions allow data to be transferred from A or transferred to A where arithmetic and logical operations
can then be performed.
For compatibility with the earlier M68HC05 Family, H is forced to 0x00 during reset. Reset has no effect
on the contents of X.
SP
PC
CONDITION CODE REGISTER
CARRY
ZERO
NEGATIVE
INTERRUPT MASK
HALF-CARRY (FROM BIT 3)
TWO’S COMPLEMENT OVERFLOW
H X
0
0
0
7
15
15
70
ACCUMULATOR A
INDEX REGISTER (LOW)INDEX REGISTER (HIGH)
STACK POINTER
87
PROGRAM COUNTER
16-BIT INDEX REGISTER H:X
CCR
CV11HINZ
Central Processor Unit (S08CPUV2)Central Processor Unit (S08CPUV2)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 89
7.2.3 Stack Pointer (SP)
This 16-bit address pointer register points at the next available location on the automatic last-in-first-out
(LIFO) stack. The stack may be located anywhere in the 64-Kbyte address space that has RAM and can
be any size up to the amount of available RAM. The stack is used to automatically save the return address
for subroutine calls, the return address and CPU registers during interrupts, and for local variables. The
AIS (add immediate to stack pointer) instruction adds an 8-bit signed immediate value to SP. This is most
often used to allocate or deallocate space for local variables on the stack.
SP is forced to 0x00FF at reset for compatibility with the earlier M68HC05 Family. HCS08 programs
normally change the value in SP to the address of the last location (highest address) in on-chip RAM
during reset initialization to free up direct page RAM (from the end of the on-chip registers to 0x00FF).
The RSP (reset stack pointer) instruction was included for compatibility with the M68HC05 Family and
is seldom used in new HCS08 programs because it only affects the low-order half of the stack pointer.
7.2.4 Program Counter (PC)
The program counter is a 16-bit register that contains the address of the next instruction or operand to be
fetched.
During normal program execution, the program counter automatically increments to the next sequential
memory location every time an instruction or operand is fetched. Jump, branch, interrupt, and return
operations load the program counter with an address other than that of the next sequential location. This
is called a change-of-flow.
During reset, the program counter is loaded with the reset vector that is located at $FFFE and $FFFF. The
vector stored there is the address of the first instruction that will be executed after exiting the reset state.
7.2.5 Condition Code Register (CCR)
The 8-bit condition code register contains the interrupt mask (I) and five flags that indicate the results of
the instruction just executed. Bits 6 and 5 are set permanently to 1. The following paragraphs describe the
functions of the condition code bits in general terms. For a more detailed explanation of how each
instruction sets the CCR bits, refer to the HCS08 Family Reference Manual, volume 1, Freescale
Semiconductor document order number HCS08RMv1/D.
Figure 7-2. Condition Code Register
CONDITION CODE REGISTER
CARRY
ZERO
NEGATIVE
INTERRUPT MASK
HALF-CARRY (FROM BIT 3)
TWO’S COMPLEMENT OVERFLOW
70
CCRCV11HINZ
Central Processor Unit (S08CPUV2)Central Processor Unit (S08CPUV2)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
90 Freescale Semiconductor
7.3 Addressing Modes
Addressing modes define the way the CPU accesses operands and data. In the HCS08, all memory, status
and control registers, and input/output (I/O) ports share a single 64-Kbyte linear address space so a 16-bit
binary address can uniquely identify any memory location. This arrangement means that the same
instructions that access variables in RAM can also be used to access I/O and control registers or nonvolatile
program space.
Some instructions use more than one addressing mode. For instance, move instructions use one addressing
mode to specify the source operand and a second addressing mode to specify the destination address.
Instructions such as BRCLR, BRSET, CBEQ, and DBNZ use one addressing mode to specify the location
Table 7-1. CCR Register Field Descriptions
Field Description
7
V
Two’s Complement Overflow Flag — The CPU sets the overflow flag when a two’s complement overflow occurs.
The signed branch instructions BGT, BGE, BLE, and BLT use the overflow flag.
0 No overflow
1 Overflow
4
H
Half-Carry Flag — The CPU sets the half-carry flag when a carry occurs between accumulator bits 3 and 4 during
an add-without-carry (ADD) or add-with-carry (ADC) operation. The half-carry flag is required for binary-coded
decimal (BCD) arithmetic operations. The DAA instruction uses the states of the H and C condition code bits to
automatically add a correction value to the result from a previous ADD or ADC on BCD operands to correct the
result to a valid BCD value.
0 No carry between bits 3 and 4
1 Carry between bits 3 and 4
3
I
Interrupt Mask Bit — When the interrupt mask is set, all maskable CPU interrupts are disabled. CPU interrupts
are enabled when the interrupt mask is cleared. When a CPU interrupt occurs, the interrupt mask is set
automatically after the CPU registers are saved on the stack, but before the first instruction of the interrupt service
routine is executed.
Interrupts are not recognized at the instruction boundary after any instruction that clears I (CLI or TAP). This
ensures that the next instruction after a CLI or TAP will always be executed without the possibility of an intervening
interrupt, provided I was set.
0 Interrupts enabled
1 Interrupts disabled
2
N
Negative Flag — The CPU sets the negative flag when an arithmetic operation, logic operation, or data
manipulation produces a negative result, setting bit 7 of the result. Simply loading or storing an 8-bit or 16-bit value
causes N to be set if the most significant bit of the loaded or stored value was 1.
0 Non-negative result
1 Negative result
1
Z
Zero Flag — The CPU sets the zero flag when an arithmetic operation, logic operation, or data manipulation
produces a result of 0x00 or 0x0000. Simply loading or storing an 8-bit or 16-bit value causes Z to be set if the
loaded or stored value was all 0s.
0 Non-zero result
1 Zero result
0
C
Carry/Borrow Flag — The CPU sets the carry/borrow flag when an addition operation produces a carry out of bit
7 of the accumulator or when a subtraction operation requires a borrow. Some instructions — such as bit test and
branch, shift, and rotate — also clear or set the carry/borrow flag.
0 No carry out of bit 7
1 Carry out of bit 7
Central Processor Unit (S08CPUV2)Central Processor Unit (S08CPUV2)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 91
of an operand for a test and then use relative addressing mode to specify the branch destination address
when the tested condition is true. For BRCLR, BRSET, CBEQ, and DBNZ, the addressing mode listed in
the instruction set tables is the addressing mode needed to access the operand to be tested, and relative
addressing mode is implied for the branch destination.
7.3.1 Inherent Addressing Mode (INH)
In this addressing mode, operands needed to complete the instruction (if any) are located within CPU
registers so the CPU does not need to access memory to get any operands.
7.3.2 Relative Addressing Mode (REL)
Relative addressing mode is used to specify the destination location for branch instructions. A signed 8-bit
offset value is located in the memory location immediately following the opcode. During execution, if the
branch condition is true, the signed offset is sign-extended to a 16-bit value and is added to the current
contents of the program counter, which causes program execution to continue at the branch destination
address.
7.3.3 Immediate Addressing Mode (IMM)
In immediate addressing mode, the operand needed to complete the instruction is included in the object
code immediately following the instruction opcode in memory. In the case of a 16-bit immediate operand,
the high-order byte is located in the next memory location after the opcode, and the low-order byte is
located in the next memory location after that.
7.3.4 Direct Addressing Mode (DIR)
In direct addressing mode, the instruction includes the low-order eight bits of an address in the direct page
(0x0000–0x00FF). During execution a 16-bit address is formed by concatenating an implied 0x00 for the
high-order half of the address and the direct address from the instruction to get the 16-bit address where
the desired operand is located. This is faster and more memory efficient than specifying a complete 16-bit
address for the operand.
7.3.5 Extended Addressing Mode (EXT)
In extended addressing mode, the full 16-bit address of the operand is located in the next two bytes of
program memory after the opcode (high byte first).
7.3.6 Indexed Addressing Mode
Indexed addressing mode has seven variations including five that use the 16-bit H:X index register pair and
two that use the stack pointer as the base reference.
Central Processor Unit (S08CPUV2)Central Processor Unit (S08CPUV2)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
92 Freescale Semiconductor
7.3.6.1 Indexed, No Offset (IX)
This variation of indexed addressing uses the 16-bit value in the H:X index register pair as the address of
the operand needed to complete the instruction.
7.3.6.2 Indexed, No Offset with Post Increment (IX+)
This variation of indexed addressing uses the 16-bit value in the H:X index register pair as the address of
the operand needed to complete the instruction. The index register pair is then incremented
(H:X = H:X + 0x0001) after the operand has been fetched. This addressing mode is only used for MOV
and CBEQ instructions.
7.3.6.3 Indexed, 8-Bit Offset (IX1)
This variation of indexed addressing uses the 16-bit value in the H:X index register pair plus an unsigned
8-bit offset included in the instruction as the address of the operand needed to complete the instruction.
7.3.6.4 Indexed, 8-Bit Offset with Post Increment (IX1+)
This variation of indexed addressing uses the 16-bit value in the H:X index register pair plus an unsigned
8-bit offset included in the instruction as the address of the operand needed to complete the instruction.
The index register pair is then incremented (H:X = H:X + 0x0001) after the operand has been fetched. This
addressing mode is used only for the CBEQ instruction.
7.3.6.5 Indexed, 16-Bit Offset (IX2)
This variation of indexed addressing uses the 16-bit value in the H:X index register pair plus a 16-bit offset
included in the instruction as the address of the operand needed to complete the instruction.
7.3.6.6 SP-Relative, 8-Bit Offset (SP1)
This variation of indexed addressing uses the 16-bit value in the stack pointer (SP) plus an unsigned 8-bit
offset included in the instruction as the address of the operand needed to complete the instruction.
7.3.6.7 SP-Relative, 16-Bit Offset (SP2)
This variation of indexed addressing uses the 16-bit value in the stack pointer (SP) plus a 16-bit offset
included in the instruction as the address of the operand needed to complete the instruction.
7.4 Special Operations
The CPU performs a few special operations that are similar to instructions but do not have opcodes like
other CPU instructions. In addition, a few instructions such as STOP and WAIT directly affect other MCU
circuitry. This section provides additional information about these operations.
Central Processor Unit (S08CPUV2)Central Processor Unit (S08CPUV2)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 93
7.4.1 Reset Sequence
Reset can be caused by a power-on-reset (POR) event, internal conditions such as the COP (computer
operating properly) watchdog, or by assertion of an external active-low reset pin. When a reset event
occurs, the CPU immediately stops whatever it is doing (the MCU does not wait for an instruction
boundary before responding to a reset event). For a more detailed discussion about how the MCU
recognizes resets and determines the source, refer to the Resets, Interrupts, and System Configuration
chapter.
The reset event is considered concluded when the sequence to determine whether the reset came from an
internal source is done and when the reset pin is no longer asserted. At the conclusion of a reset event, the
CPU performs a 6-cycle sequence to fetch the reset vector from 0xFFFE and 0xFFFF and to fill the
instruction queue in preparation for execution of the first program instruction.
7.4.2 Interrupt Sequence
When an interrupt is requested, the CPU completes the current instruction before responding to the
interrupt. At this point, the program counter is pointing at the start of the next instruction, which is where
the CPU should return after servicing the interrupt. The CPU responds to an interrupt by performing the
same sequence of operations as for a software interrupt (SWI) instruction, except the address used for the
vector fetch is determined by the highest priority interrupt that is pending when the interrupt sequence
started.
The CPU sequence for an interrupt is:
1. Store the contents of PCL, PCH, X, A, and CCR on the stack, in that order.
2. Set the I bit in the CCR.
3. Fetch the high-order half of the interrupt vector.
4. Fetch the low-order half of the interrupt vector.
5. Delay for one free bus cycle.
6. Fetch three bytes of program information starting at the address indicated by the interrupt vector
to fill the instruction queue in preparation for execution of the first instruction in the interrupt
service routine.
After the CCR contents are pushed onto the stack, the I bit in the CCR is set to prevent other interrupts
while in the interrupt service routine. Although it is possible to clear the I bit with an instruction in the
interrupt service routine, this would allow nesting of interrupts (which is not recommended because it
leads to programs that are difficult to debug and maintain).
For compatibility with the earlier M68HC05 MCUs, the high-order half of the H:X index register pair (H)
is not saved on the stack as part of the interrupt sequence. The user must use a PSHH instruction at the
beginning of the service routine to save H and then use a PULH instruction just before the RTI that ends
the interrupt service routine. It is not necessary to save H if you are certain that the interrupt service routine
does not use any instructions or auto-increment addressing modes that might change the value of H.
The software interrupt (SWI) instruction is like a hardware interrupt except that it is not masked by the
global I bit in the CCR and it is associated with an instruction opcode within the program so it is not
asynchronous to program execution.
Central Processor Unit (S08CPUV2)Central Processor Unit (S08CPUV2)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
94 Freescale Semiconductor
7.4.3 Wait Mode Operation
The WAIT instruction enables interrupts by clearing the I bit in the CCR. It then halts the clocks to the
CPU to reduce overall power consumption while the CPU is waiting for the interrupt or reset event that
will wake the CPU from wait mode. When an interrupt or reset event occurs, the CPU clocks will resume
and the interrupt or reset event will be processed normally.
If a serial BACKGROUND command is issued to the MCU through the background debug interface while
the CPU is in wait mode, CPU clocks will resume and the CPU will enter active background mode where
other serial background commands can be processed. This ensures that a host development system can still
gain access to a target MCU even if it is in wait mode.
7.4.4 Stop Mode Operation
Usually, all system clocks, including the crystal oscillator (when used), are halted during stop mode to
minimize power consumption. In such systems, external circuitry is needed to control the time spent in
stop mode and to issue a signal to wake up the target MCU when it is time to resume processing. Unlike
the earlier M68HC05 and M68HC08 MCUs, the HCS08 can be configured to keep a minimum set of
clocks running in stop mode. This optionally allows an internal periodic signal to wake the target MCU
from stop mode.
When a host debug system is connected to the background debug pin (BKGD) and the ENBDM control
bit has been set by a serial command through the background interface (or because the MCU was reset into
active background mode), the oscillator is forced to remain active when the MCU enters stop mode. In this
case, if a serial BACKGROUND command is issued to the MCU through the background debug interface
while the CPU is in stop mode, CPU clocks will resume and the CPU will enter active background mode
where other serial background commands can be processed. This ensures that a host development system
can still gain access to a target MCU even if it is in stop mode.
Recovery from stop mode depends on the particular HCS08 and whether the oscillator was stopped in stop
mode. Refer to the Modes of Operation chapter for more details.
7.4.5 BGND Instruction
The BGND instruction is new to the HCS08 compared to the M68HC08. BGND would not be used in
normal user programs because it forces the CPU to stop processing user instructions and enter the active
background mode. The only way to resume execution of the user program is through reset or by a host
debug system issuing a GO, TRACE1, or TAGGO serial command through the background debug
interface.
Software-based breakpoints can be set by replacing an opcode at the desired breakpoint address with the
BGND opcode. When the program reaches this breakpoint address, the CPU is forced to active background
mode rather than continuing the user program.
Central Processor Unit (S08CPUV2)Central Processor Unit (S08CPUV2)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 95
7.5 HCS08 Instruction Set Summary
Instruction Set Summary Nomenclature
The nomenclature listed here is used in the instruction descriptions in Table 7-2.
Operators
( ) = Contents of register or memory location shown inside parentheses
←=Is loaded with (read: “gets”)
&=Boolean AND
|=Boolean OR
⊕=Boolean exclusive-OR
×=Multiply
÷=Divide
:=Concatenate
+=Add
–=Negate (two’s complement)
CPU registers
A=Accumulator
CCR = Condition code register
H=Index register, higher order (most significant) 8 bits
X=Index register, lower order (least significant) 8 bits
PC = Program counter
PCH = Program counter, higher order (most significant) 8 bits
PCL = Program counter, lower order (least significant) 8 bits
SP = Stack pointer
Memory and addressing
M=A memory location or absolute data, depending on addressing mode
M:M + 0x0001= A 16-bit value in two consecutive memory locations. The higher-order (most
significant) 8 bits are located at the address of M, and the lower-order (least
significant) 8 bits are located at the next higher sequential address.
Condition code register (CCR) bits
V=Two’s complement overflow indicator, bit 7
H=Half carry, bit 4
I=Interrupt mask, bit 3
N=Negative indicator, bit 2
Z=Zero indicator, bit 1
C=Carry/borrow, bit 0 (carry out of bit 7)
CCR activity notation
–=Bit not affected
Central Processor Unit (S08CPUV2)Central Processor Unit (S08CPUV2)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
96 Freescale Semiconductor
0=Bit forced to 0
1=Bit forced to 1
=Bit set or cleared according to results of operation
U=Undefined after the operation
Machine coding notation
dd = Low-order 8 bits of a direct address 0x0000–0x00FF (high byte assumed to be 0x00)
ee = Upper 8 bits of 16-bit offset
ff = Lower 8 bits of 16-bit offset or 8-bit offset
ii = One byte of immediate data
jj = High-order byte of a 16-bit immediate data value
kk = Low-order byte of a 16-bit immediate data value
hh = High-order byte of 16-bit extended address
ll = Low-order byte of 16-bit extended address
rr = Relative offset
Source form
Everything in the source forms columns, except expressions in italic characters, is literal information that
must appear in the assembly source file exactly as shown. The initial 3- to 5-letter mnemonic is always a
literal expression. All commas, pound signs (#), parentheses, and plus signs (+) are literal characters.
n—Any label or expression that evaluates to a single integer in the range 0–7
opr8i —Any label or expression that evaluates to an 8-bit immediate value
opr16i —Any label or expression that evaluates to a 16-bit immediate value
opr8a —Any label or expression that evaluates to an 8-bit value. The instruction treats this 8-bit
value as the low order 8 bits of an address in the direct page of the 64-Kbyte address
space (0x00xx).
opr16a —Any label or expression that evaluates to a 16-bit value. The instruction treats this
value as an address in the 64-Kbyte address space.
oprx8 —Any label or expression that evaluates to an unsigned 8-bit value, used for indexed
addressing
oprx16 —Any label or expression that evaluates to a 16-bit value. Because the HCS08 has a
16-bit address bus, this can be either a signed or an unsigned value.
rel —Any label or expression that refers to an address that is within –128 to +127 locations
from the next address after the last byte of object code for the current instruction. The
assembler will calculate the 8-bit signed offset and include it in the object code for this
instruction.
Address modes
INH = Inherent (no operands)
IMM = 8-bit or 16-bit immediate
DIR = 8-bit direct
EXT = 16-bit extended
Central Processor Unit (S08CPUV2)Central Processor Unit (S08CPUV2)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 97
IX = 16-bit indexed no offset
IX+ = 16-bit indexed no offset, post increment (CBEQ and MOV only)
IX1 = 16-bit indexed with 8-bit offset from H:X
IX1+ = 16-bit indexed with 8-bit offset, post increment
(CBEQ only)
IX2 = 16-bit indexed with 16-bit offset from H:X
REL = 8-bit relative offset
SP1 = Stack pointer with 8-bit offset
SP2 = Stack pointer with 16-bit offset
Table 7-2. HCS08 Instruction Set Summary (Sheet 1 of 7)
Source
Form Operation Description
Effect
on CCR
Address
Mode
Opcode
Operand
Bus Cycles1
VH I NZC
ADC #opr8i
ADC opr8a
ADC opr16a
ADC oprx16,X
ADC oprx8,X
ADC ,X
ADC oprx16,SP
ADC oprx8,SP
Add with Carry A ← (A) + (M) + (C) –
IMM
DIR
EXT
IX2
IX1
IX
SP2
SP1
A9
B9
C9
D9
E9
F9
9ED9
9EE9
ii
dd
hh ll
ee ff
ff
ee ff
ff
2
3
4
4
3
3
5
4
ADD #opr8i
ADD opr8a
ADD opr16a
ADD oprx16,X
ADD oprx8,X
ADD ,X
ADD oprx16,SP
ADD oprx8,SP
Add without Carry A ← (A) + (M) –
IMM
DIR
EXT
IX2
IX1
IX
SP2
SP1
AB
BB
CB
DB
EB
FB
9EDB
9EEB
ii
dd
hh ll
ee ff
ff
ee ff
ff
2
3
4
4
3
3
5
4
AIS #opr8i Add Immediate Value
(Signed) to Stack Pointer
SP ← (SP) + (M)
M is sign extended to a 16-bit value – – – – – – IMM A7 ii 2
AIX #opr8i
Add Immediate Value
(Signed) to Index
Register (H:X)
H:X ← (H:X) + (M)
M is sign extended to a 16-bit value – – – – – – IMM AF ii 2
AND #opr8i
AND opr8a
AND opr16a
AND oprx16,X
AND oprx8,X
AND ,X
AND oprx16,SP
AND oprx8,SP
Logical AND A ← (A) & (M) 0 – – –
IMM
DIR
EXT
IX2
IX1
IX
SP2
SP1
A4
B4
C4
D4
E4
F4
9ED4
9EE4
ii
dd
hh ll
ee ff
ff
ee ff
ff
2
3
4
4
3
3
5
4
ASL opr8a
ASLA
ASLX
ASL oprx8,X
ASL ,X
ASL oprx8,SP
Arithmetic Shift Left
(Same as LSL) ––
DIR
INH
INH
IX1
IX
SP1
38
48
58
68
78
9E68
dd
ff
ff
5
1
1
5
4
6
ASR opr8a
ASRA
ASRX
ASR oprx8,X
ASR ,X
ASR oprx8,SP
Arithmetic Shift Right – –
DIR
INH
INH
IX1
IX
SP1
37
47
57
67
77
9E67
dd
ff
ff
5
1
1
5
4
6
BCC rel Branch if Carry Bit Clear Branch if (C) = 0 – – – – – – REL 24 rr 3
C
b0
b7
0
b0
b7
C
Central Processor Unit (S08CPUV2)Central Processor Unit (S08CPUV2)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
98 Freescale Semiconductor
BCLR n,opr8a Clear Bit n in Memory Mn ← 0
––––––DIR (b0)
DIR (b1)
DIR (b2)
DIR (b3)
DIR (b4)
DIR (b5)
DIR (b6)
DIR (b7)
11
13
15
17
19
1B
1D
1F
dd
dd
dd
dd
dd
dd
dd
dd
5
5
5
5
5
5
5
5
BCS rel Branch if Carry Bit Set
(Same as BLO) Branch if (C) = 1 ––––––REL 25 rr 3
BEQ rel Branch if Equal Branch if (Z) = 1 ––––––REL 27 rr 3
BGE rel
Branch if Greater Than or
Equal To
(Signed Operands)
Branch if (N ⊕ V) = 0 ––––––REL 90 rr 3
BGND Enter Active Background
if ENBDM = 1
Waits For and Processes BDM
Commands Until GO, TRACE1, or
TAGGO
––––––INH 82 5+
BGT rel Branch if Greater Than
(Signed Operands) Branch if (Z) | (N ⊕ V) = 0 ––––––REL 92 rr 3
BHCC rel Branch if Half Carry Bit
Clear Branch if (H) = 0 ––––––REL 28 rr 3
BHCS rel Branch if Half Carry Bit
Set Branch if (H) = 1 ––––––REL 29 rr 3
BHI rel Branch if Higher Branch if (C) | (Z) = 0 ––––––REL 22 rr 3
BHS rel Branch if Higher or Same
(Same as BCC) Branch if (C) = 0 ––––––REL 24 rr 3
BIH rel Branch if IRQ Pin High Branch if IRQ pin = 1 ––––––REL 2F rr 3
BIL rel Branch if IRQ Pin Low Branch if IRQ pin = 0 –––––– REL 2E rr 3
BIT #opr8i
BIT opr8a
BIT opr16a
BIT oprx16,X
BIT oprx8,X
BIT ,X
BIT oprx16,SP
BIT oprx8,SP
Bit Test
(A) & (M)
(CCR Updated but Operands
Not Changed)
0––
–
IMM
DIR
EXT
IX2
IX1
IX
SP2
SP1
A5
B5
C5
D5
E5
F5
9ED5
9EE5
ii
dd
hh ll
ee ff
ff
ee ff
ff
2
3
4
4
3
3
5
4
BLE rel
Branch if Less Than
or Equal To
(Signed Operands)
Branch if (Z) | (N ⊕V) = 1 –––––– REL 93 rr 3
BLO rel Branch if Lower
(Same as BCS) Branch if (C) = 1 ––––––REL 25 rr 3
BLS rel Branch if Lower or Same Branch if (C) | (Z) = 1 –––––– REL 23 rr 3
BLT rel Branch if Less Than
(Signed Operands) Branch if (N ⊕ V ) = 1–––––– REL 91 rr 3
BMC rel Branch if Interrupt Mask
Clear Branch if (I) = 0 –––––– REL 2C rr 3
BMI rel Branch if Minus Branch if (N) = 1 –––––– REL 2B rr 3
BMS rel Branch if Interrupt Mask
Set Branch if (I) = 1 –––––– REL 2D rr 3
BNE rel Branch if Not Equal Branch if (Z) = 0 –––––– REL 26 rr 3
BPL rel Branch if Plus Branch if (N) = 0 –––––– REL 2A rr 3
BRA rel Branch Always No Test –––––– REL 20 rr 3
Table 7-2. HCS08 Instruction Set Summary (Sheet 2 of 7)
Source
Form Operation Description
Effect
on CCR
Address
Mode
Opcode
Operand
Bus Cycles1
VH I NZC
Central Processor Unit (S08CPUV2)Central Processor Unit (S08CPUV2)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 99
BRCLR n,opr8a,rel Branch if Bit nin Memory
Clear Branch if (Mn) = 0
––––– DIR (b0)
DIR (b1)
DIR (b2)
DIR (b3)
DIR (b4)
DIR (b5)
DIR (b6)
DIR (b7)
01
03
05
07
09
0B
0D
0F
dd rr
dd rr
dd rr
dd rr
dd rr
dd rr
dd rr
dd rr
5
5
5
5
5
5
5
5
BRN rel Branch Never Uses 3 Bus Cycles ––––––REL 21 rr 3
BRSET n,opr8a,rel Branch if Bit nin Memory
Set Branch if (Mn) = 1
––––– DIR (b0)
DIR (b1)
DIR (b2)
DIR (b3)
DIR (b4)
DIR (b5)
DIR (b6)
DIR (b7)
00
02
04
06
08
0A
0C
0E
dd rr
dd rr
dd rr
dd rr
dd rr
dd rr
dd rr
dd rr
5
5
5
5
5
5
5
5
BSET n,opr8a Set Bit nin Memory Mn ← 1
––––––DIR (b0)
DIR (b1)
DIR (b2)
DIR (b3)
DIR (b4)
DIR (b5)
DIR (b6)
DIR (b7)
10
12
14
16
18
1A
1C
1E
dd
dd
dd
dd
dd
dd
dd
dd
5
5
5
5
5
5
5
5
BSR rel Branch to Subroutine
PC ←(PC) + 0x0002
push (PCL); SP ← (SP) – 0x0001
push (PCH); SP ← (SP) – 0x0001
PC ← (PC) + rel
––––––
REL AD rr 5
CBEQ opr8a,rel
CBEQA #opr8i,rel
CBEQX #opr8i,rel
CBEQ oprx8,X+,rel
CBEQ ,X+,rel
CBEQ oprx8,SP,rel
Compare and Branch if
Equal
Branch if (A) = (M)
Branch if (A) = (M)
Branch if (X) = (M)
Branch if (A) = (M)
Branch if (A) = (M)
Branch if (A) = (M)
––––––DIR
IMM
IMM
IX1+
IX+
SP1
31
41
51
61
71
9E61
dd rr
ii rr
ii rr
ff rr
rr
ff rr
5
4
4
5
5
6
CLC Clear Carry Bit C ← 0 –––––0INH 98 1
CLI Clear Interrupt Mask Bit I ← 0 ––0–––INH 9A 1
CLR opr8a
CLRA
CLRX
CLRH
CLR oprx8,X
CLR ,X
CLR oprx8,SP
Clear
M← 0x00
A← 0x00
X← 0x00
H← 0x00
M← 0x00
M← 0x00
M← 0x00
0––01–DIR
INH
INH
INH
IX1
IX
SP1
3F
4F
5F
8C
6F
7F
9E6F
dd
ff
ff
5
1
1
1
5
4
6
CMP #opr8i
CMP opr8a
CMP opr16a
CMP oprx16,X
CMP oprx8,X
CMP ,X
CMP oprx16,SP
CMP oprx8,SP
Compare Accumulator
with Memory
(A) – (M)
(CCR Updated But Operands Not
Changed)
–– IMM
DIR
EXT
IX2
IX1
IX
SP2
SP1
A1
B1
C1
D1
E1
F1
9ED1
9EE1
ii
dd
hh ll
ee ff
ff
ee ff
ff
2
3
4
4
3
3
5
4
COM opr8a
COMA
COMX
COM oprx8,X
COM ,X
COM oprx8,SP
Complement
(One’s Complement)
M← (M)= 0xFF – (M)
A← (A) = 0xFF – (A)
X← (X) = 0xFF – (X)
M← (M) = 0xFF – (M)
M← (M) = 0xFF – (M)
M← (M) = 0xFF – (M)
0–– 1DIR
INH
INH
IX1
IX
SP1
33
43
53
63
73
9E63
dd
ff
ff
5
1
1
5
4
6
CPHX opr16a
CPHX #opr16i
CPHX opr8a
CPHX oprx8,SP
Compare Index Register
(H:X) with Memory
(H:X) – (M:M + 0x0001)
(CCR Updated But Operands Not
Changed)
–– EXT
IMM
DIR
SP1
3E
65
75
9EF3
hh ll
jj kk
dd
ff
6
3
5
6
Table 7-2. HCS08 Instruction Set Summary (Sheet 3 of 7)
Source
Form Operation Description
Effect
on CCR
Address
Mode
Opcode
Operand
Bus Cycles1
VH I NZC
Central Processor Unit (S08CPUV2)Central Processor Unit (S08CPUV2)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
100 Freescale Semiconductor
CPX #opr8i
CPX opr8a
CPX opr16a
CPX oprx16,X
CPX oprx8,X
CPX ,X
CPX oprx16,SP
CPX oprx8,SP
Compare X (Index
Register Low) with
Memory
(X) – (M)
(CCR Updated But Operands Not
Changed)
–– IMM
DIR
EXT
IX2
IX1
IX
SP2
SP1
A3
B3
C3
D3
E3
F3
9ED3
9EE3
ii
dd
hh ll
ee ff
ff
ee ff
ff
2
3
4
4
3
3
5
4
DAA
Decimal Adjust
Accumulator After ADD or
ADC of BCD Values
(A)10
U– – INH 72 1
DBNZ opr8a,rel
DBNZA rel
DBNZX rel
DBNZ oprx8,X,rel
DBNZ ,X,rel
DBNZ oprx8,SP,rel
Decrement and Branch if
Not Zero
Decrement A, X, or M
Branch if (result) ≠0
DBNZX Affects X Not H
––––––DIR
INH
INH
IX1
IX
SP1
3B
4B
5B
6B
7B
9E6B
dd rr
rr
rr
ff rr
rr
ff rr
7
4
4
7
6
8
DEC opr8a
DECA
DECX
DEC oprx8,X
DEC ,X
DEC oprx8,SP
Decrement
M← (M) – 0x01
A← (A) – 0x01
X← (X) – 0x01
M← (M) – 0x01
M← (M) – 0x01
M← (M) – 0x01
––
–
DIR
INH
INH
IX1
IX
SP1
3A
4A
5A
6A
7A
9E6A
dd
ff
ff
5
1
1
5
4
6
DIV Divide A← (H:A)÷(X)
H← Remainder –––– INH 52 6
EOR #opr8i
EOR opr8a
EOR opr16a
EOR oprx16,X
EOR oprx8,X
EOR ,X
EOR oprx16,SP
EOR oprx8,SP
Exclusive OR
Memory with
Accumulator
A← (A ⊕ M)
0–– –IMM
DIR
EXT
IX2
IX1
IX
SP2
SP1
A8
B8
C8
D8
E8
F8
9ED8
9EE8
ii
dd
hh ll
ee ff
ff
ee ff
ff
2
3
4
4
3
3
5
4
INC opr8a
INCA
INCX
INC oprx8,X
INC ,X
INC oprx8,SP
Increment
M← (M) + 0x01
A← (A) + 0x01
X← (X) + 0x01
M← (M) + 0x01
M← (M) + 0x01
M← (M) + 0x01
–– –DIR
INH
INH
IX1
IX
SP1
3C
4C
5C
6C
7C
9E6C
dd
ff
ff
5
1
1
5
4
6
JMP opr8a
JMP opr16a
JMP oprx16,X
JMP oprx8,X
JMP ,X
Jump PC ← Jump Address
––––––DIR
EXT
IX2
IX1
IX
BC
CC
DC
EC
FC
dd
hh ll
ee ff
ff
3
4
4
3
3
JSR opr8a
JSR opr16a
JSR oprx16,X
JSR oprx8,X
JSR ,X
Jump to Subroutine
PC ← (PC) + n (n = 1, 2, or 3)
Push (PCL); SP ← (SP) – 0x0001
Push (PCH); SP ← (SP) – 0x0001
PC ← Unconditional Address
––––––DIR
EXT
IX2
IX1
IX
BD
CD
DD
ED
FD
dd
hh ll
ee ff
ff
5
6
6
5
5
LDA #opr8i
LDA opr8a
LDA opr16a
LDA oprx16,X
LDA oprx8,X
LDA ,X
LDA oprx16,SP
LDA oprx8,SP
Load Accumulator from
Memory A← (M)
0–– –IMM
DIR
EXT
IX2
IX1
IX
SP2
SP1
A6
B6
C6
D6
E6
F6
9ED6
9EE6
ii
dd
hh ll
ee ff
ff
ee ff
ff
2
3
4
4
3
3
5
4
LDHX #opr16i
LDHX opr8a
LDHX opr16a
LDHX ,X
LDHX oprx16,X
LDHX oprx8,X
LDHX oprx8,SP
Load Index Register (H:X)
from Memory H:X ← (M:M + 0x0001)
0–– –IMM
DIR
EXT
IX
IX2
IX1
SP1
45
55
32
9EAE
9EBE
9ECE
9EFE
jj kk
dd
hh ll
ee ff
ff
ff
3
4
5
5
6
5
5
Table 7-2. HCS08 Instruction Set Summary (Sheet 4 of 7)
Source
Form Operation Description
Effect
on CCR
Address
Mode
Opcode
Operand
Bus Cycles1
VH I NZC
Central Processor Unit (S08CPUV2)Central Processor Unit (S08CPUV2)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 101
LDX #opr8i
LDX opr8a
LDX opr16a
LDX oprx16,X
LDX oprx8,X
LDX ,X
LDX oprx16,SP
LDX oprx8,SP
Load X (Index Register
Low) from Memory X← (M)
0–– –IMM
DIR
EXT
IX2
IX1
IX
SP2
SP1
AE
BE
CE
DE
EE
FE
9EDE
9EEE
ii
dd
hh ll
ee ff
ff
ee ff
ff
2
3
4
4
3
3
5
4
LSL opr8a
LSLA
LSLX
LSL oprx8,X
LSL ,X
LSL oprx8,SP
Logical Shift Left
(Same as ASL)
–– DIR
INH
INH
IX1
IX
SP1
38
48
58
68
78
9E68
dd
ff
ff
5
1
1
5
4
6
LSR opr8a
LSRA
LSRX
LSR oprx8,X
LSR ,X
LSR oprx8,SP
Logical Shift Right
––0 DIR
INH
INH
IX1
IX
SP1
34
44
54
64
74
9E64
dd
ff
ff
5
1
1
5
4
6
MOV opr8a,opr8a
MOV opr8a,X+
MOV #opr8i,opr8a
MOV ,X+,opr8a
Move
(M)destination ←(M)source
H:X ← (H:X) + 0x0001 in
IX+/DIR and DIR/IX+ Modes
0–– –DIR/DIR
DIR/IX+
IMM/DIR
IX+/DIR
4E
5E
6E
7E
dd dd
dd
ii dd
dd
5
5
4
5
MUL Unsigned multiply X:A ← (X) × (A) –0–––0INH 42 5
NEG opr8a
NEGA
NEGX
NEG oprx8,X
NEG ,X
NEG oprx8,SP
Negate
(Two’s Complement)
M← – (M) = 0x00 – (M)
A← – (A) = 0x00 – (A)
X← – (X) = 0x00 – (X)
M← – (M) = 0x00 – (M)
M← – (M) = 0x00 – (M)
M← – (M) = 0x00 – (M)
–– DIR
INH
INH
IX1
IX
SP1
30
40
50
60
70
9E60
dd
ff
ff
5
1
1
5
4
6
NOP No Operation Uses 1 Bus Cycle ––––––INH 9D 1
NSA Nibble Swap
Accumulator A← (A[3:0]:A[7:4]) ––––––INH 62 1
ORA #opr8i
ORA opr8a
ORA opr16a
ORA oprx16,X
ORA oprx8,X
ORA ,X
ORA oprx16,SP
ORA oprx8,SP
Inclusive OR Accumulator
and Memory A← (A) | (M)
0–– –IMM
DIR
EXT
IX2
IX1
IX
SP2
SP1
AA
BA
CA
DA
EA
FA
9EDA
9EEA
ii
dd
hh ll
ee ff
ff
ee ff
ff
2
3
4
4
3
3
5
4
PSHA Push Accumulator onto
Stack Push (A); SP ←(SP) – 0x0001 ––––––INH 87 2
PSHH Push H (Index Register
High) onto Stack Push (H); SP ←(SP) – 0x0001 ––––––INH 8B 2
PSHX Push X (Index Register
Low) onto Stack Push (X);SP ←(SP) – 0x0001 ––––––INH 89 2
PULA Pull Accumulator from
Stack SP ←(SP + 0x0001); Pull (A)––––––INH 86 3
PULH Pull H (Index Register
High) from Stack SP ←(SP + 0x0001); Pull (H)––––––INH 8A 3
PULX Pull X (Index Register
Low) from Stack SP ←(SP + 0x0001); Pull (X)––––––INH 88 3
ROL opr8a
ROLA
ROLX
ROL oprx8,X
ROL ,X
ROL oprx8,SP
Rotate Left through Carry
–– DIR
INH
INH
IX1
IX
SP1
39
49
59
69
79
9E69
dd
ff
ff
5
1
1
5
4
6
Table 7-2. HCS08 Instruction Set Summary (Sheet 5 of 7)
Source
Form Operation Description
Effect
on CCR
Address
Mode
Opcode
Operand
Bus Cycles1
VH I NZC
C
b0
b7
0
b0
b7
C0
C
b0
b7
Central Processor Unit (S08CPUV2)Central Processor Unit (S08CPUV2)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
102 Freescale Semiconductor
ROR opr8a
RORA
RORX
ROR oprx8,X
ROR ,X
ROR oprx8,SP
Rotate Right through
Carry
–– DIR
INH
INH
IX1
IX
SP1
36
46
56
66
76
9E66
dd
ff
ff
5
1
1
5
4
6
RSP Reset Stack Pointer SP ← 0xFF
(High Byte Not Affected) ––––––INH 9C 1
RTI Return from Interrupt
SP ← (SP) + 0x0001; Pull (CCR)
SP ← (SP) + 0x0001; Pull (A)
SP ← (SP) + 0x0001; Pull (X)
SP ← (SP) + 0x0001; Pull (PCH)
SP ← (SP) + 0x0001; Pull (PCL)
INH 80 9
RTS Return from Subroutine SP ← SP + 0x0001;Pull (PCH)
SP ← SP + 0x0001; Pull (PCL) ––––––INH 81 6
SBC #opr8i
SBC opr8a
SBC opr16a
SBC oprx16,X
SBC oprx8,X
SBC ,X
SBC oprx16,SP
SBC oprx8,SP
Subtract with Carry A ← (A) – (M) – (C)
–– IMM
DIR
EXT
IX2
IX1
IX
SP2
SP1
A2
B2
C2
D2
E2
F2
9ED2
9EE2
ii
dd
hh ll
ee ff
ff
ee ff
ff
2
3
4
4
3
3
5
4
SEC Set Carry Bit C ← 1 –––––1 INH 99 1
SEI Set Interrupt Mask Bit I ← 1 ––1–––INH 9B 1
STA opr8a
STA opr16a
STA oprx16,X
STA oprx8,X
STA ,X
STA oprx16,SP
STA oprx8,SP
Store Accumulator in
Memory M←(A)
0–– –DIR
EXT
IX2
IX1
IX
SP2
SP1
B7
C7
D7
E7
F7
9ED7
9EE7
dd
hh ll
ee ff
ff
ee ff
ff
3
4
4
3
2
5
4
STHX opr8a
STHX opr16a
STHX oprx8,SP
Store H:X (Index Reg.) (M:M + 0x0001) ← (H:X) 0–– –DIR
EXT
SP1
35
96
9EFF
dd
hh ll
ff
4
5
5
STOP
Enable Interrupts:
Stop Processing
Refer to MCU
Documentation
I bit ← 0; Stop Processing
––0–––
INH 8E 2+
STX opr8a
STX opr16a
STX oprx16,X
STX oprx8,X
STX ,X
STX oprx16,SP
STX oprx8,SP
Store X (Low 8 Bits of
Index Register)
in Memory
M←(X)
0–– –DIR
EXT
IX2
IX1
IX
SP2
SP1
BF
CF
DF
EF
FF
9EDF
9EEF
dd
hh ll
ee ff
ff
ee ff
ff
3
4
4
3
2
5
4
SUB #opr8i
SUB opr8a
SUB opr16a
SUB oprx16,X
SUB oprx8,X
SUB ,X
SUB oprx16,SP
SUB oprx8,SP
Subtract A ← (A) – (M)
–– IMM
DIR
EXT
IX2
IX1
IX
SP2
SP1
A0
B0
C0
D0
E0
F0
9ED0
9EE0
ii
dd
hh ll
ee ff
ff
ee ff
ff
2
3
4
4
3
3
5
4
SWI Software Interrupt
PC ← (PC) + 0x0001
Push (PCL); SP ← (SP) – 0x0001
Push (PCH); SP ← (SP) – 0x0001
Push (X); SP ← (SP) – 0x0001
Push (A); SP ← (SP) – 0x0001
Push (CCR); SP ← (SP) – 0x0001
I← 1;
PCH ← Interrupt Vector High Byte
PCL ← Interrupt Vector Low Byte
––1–––
INH 83 11
Table 7-2. HCS08 Instruction Set Summary (Sheet 6 of 7)
Source
Form Operation Description
Effect
on CCR
Address
Mode
Opcode
Operand
Bus Cycles1
VH I NZC
b0
b7
C
Central Processor Unit (S08CPUV2)Central Processor Unit (S08CPUV2)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 103
TAP Transfer Accumulator to
CCR CCR ← (A) INH 84 1
TAX Transfer Accumulator to
X (Index Register Low) X← (A) ––––––INH 97 1
TPA Transfer CCR to
Accumulator A← (CCR) ––––––INH 85 1
TST opr8a
TSTA
TSTX
TST oprx8,X
TST ,X
TST oprx8,SP
Test for Negative or Zero
(M) – 0x00
(A) – 0x00
(X) – 0x00
(M) – 0x00
(M) – 0x00
(M) – 0x00
0–– –DIR
INH
INH
IX1
IX
SP1
3D
4D
5D
6D
7D
9E6D
dd
ff
ff
4
1
1
4
3
5
TSX Transfer SP to Index Reg. H:X ← (SP) + 0x0001 ––––––INH 95 2
TXA Transfer X (Index Reg.
Low) to Accumulator A← (X) ––––––INH 9F 1
TXS Transfer Index Reg. to SP SP ← (H:X) – 0x0001 ––––––INH 94 2
WAIT Enable Interrupts; Wait
for Interrupt I bit ← 0; Halt CPU ––0–––INH 8F 2+
1Bus clock frequency is one-half of the CPU clock frequency.
Table 7-2. HCS08 Instruction Set Summary (Sheet 7 of 7)
Source
Form Operation Description
Effect
on CCR
Address
Mode
Opcode
Operand
Bus Cycles1
VH I NZC
Central Processor Unit (S08CPUV2)Central Processor Unit (S08CPUV2)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
104 Freescale Semiconductor
Table 7-3. Opcode Map (Sheet 1 of 2)
Bit-Manipulation Branch Read-Modify-Write Control Register/Memory
00 5
BRSET0
3 DIR
10 5
BSET0
2 DIR
20 3
BRA
2 REL
30 5
NEG
2 DIR
40 1
NEGA
1 INH
50 1
NEGX
1 INH
60 5
NEG
2 IX1
70 4
NEG
1IX
80 9
RTI
1 INH
90 3
BGE
2 REL
A0 2
SUB
2 IMM
B0 3
SUB
2 DIR
C0 4
SUB
3 EXT
D0 4
SUB
3 IX2
E0 3
SUB
2IX1
F0 3
SUB
1IX
01 5
BRCLR0
3 DIR
11 5
BCLR0
2 DIR
21 3
BRN
2 REL
31 5
CBEQ
3 DIR
41 4
CBEQA
3 IMM
51 4
CBEQX
3IMM
61 5
CBEQ
3 IX1+
71 5
CBEQ
2 IX+
81 6
RTS
1 INH
91 3
BLT
2 REL
A1 2
CMP
2 IMM
B1 3
CMP
2 DIR
C1 4
CMP
3 EXT
D1 4
CMP
3 IX2
E1 3
CMP
2IX1
F1 3
CMP
1IX
02 5
BRSET1
3 DIR
12 5
BSET1
2 DIR
22 3
BHI
2 REL
32 5
LDHX
3 EXT
42 5
MUL
1 INH
52 6
DIV
1 INH
62 1
NSA
1 INH
72 1
DAA
1 INH
82 5+
BGND
1 INH
92 3
BGT
2 REL
A2 2
SBC
2 IMM
B2 3
SBC
2 DIR
C2 4
SBC
3 EXT
D2 4
SBC
3 IX2
E2 3
SBC
2IX1
F2 3
SBC
1IX
03 5
BRCLR1
3 DIR
13 5
BCLR1
2 DIR
23 3
BLS
2 REL
33 5
COM
2 DIR
43 1
COMA
1 INH
53 1
COMX
1 INH
63 5
COM
2 IX1
73 4
COM
1IX
83 11
SWI
1 INH
93 3
BLE
2 REL
A3 2
CPX
2 IMM
B3 3
CPX
2 DIR
C3 4
CPX
3 EXT
D3 4
CPX
3 IX2
E3 3
CPX
2IX1
F3 3
CPX
1IX
04 5
BRSET2
3 DIR
14 5
BSET2
2 DIR
24 3
BCC
2 REL
34 5
LSR
2 DIR
44 1
LSRA
1 INH
54 1
LSRX
1 INH
64 5
LSR
2 IX1
74 4
LSR
1IX
84 1
TAP
1 INH
94 2
TXS
1 INH
A4 2
AND
2 IMM
B4 3
AND
2 DIR
C4 4
AND
3 EXT
D4 4
AND
3 IX2
E4 3
AND
2IX1
F4 3
AND
1IX
05 5
BRCLR2
3 DIR
15 5
BCLR2
2 DIR
25 3
BCS
2 REL
35 4
STHX
2 DIR
45 3
LDHX
3 IMM
55 4
LDHX
2 DIR
65 3
CPHX
3IMM
75 5
CPHX
2 DIR
85 1
TPA
1 INH
95 2
TSX
1 INH
A5 2
BIT
2 IMM
B5 3
BIT
2 DIR
C5 4
BIT
3 EXT
D5 4
BIT
3 IX2
E5 3
BIT
2IX1
F5 3
BIT
1IX
06 5
BRSET3
3 DIR
16 5
BSET3
2 DIR
26 3
BNE
2 REL
36 5
ROR
2 DIR
46 1
RORA
1 INH
56 1
RORX
1 INH
66 5
ROR
2 IX1
76 4
ROR
1IX
86 3
PULA
1 INH
96 5
STHX
3 EXT
A6 2
LDA
2 IMM
B6 3
LDA
2 DIR
C6 4
LDA
3 EXT
D6 4
LDA
3 IX2
E6 3
LDA
2IX1
F6 3
LDA
1IX
07 5
BRCLR3
3 DIR
17 5
BCLR3
2 DIR
27 3
BEQ
2 REL
37 5
ASR
2 DIR
47 1
ASRA
1 INH
57 1
ASRX
1 INH
67 5
ASR
2 IX1
77 4
ASR
1IX
87 2
PSHA
1 INH
97 1
TAX
1 INH
A7 2
AIS
2 IMM
B7 3
STA
2 DIR
C7 4
STA
3 EXT
D7 4
STA
3 IX2
E7 3
STA
2IX1
F7 2
STA
1IX
08 5
BRSET4
3 DIR
18 5
BSET4
2 DIR
28 3
BHCC
2 REL
38 5
LSL
2 DIR
48 1
LSLA
1 INH
58 1
LSLX
1 INH
68 5
LSL
2 IX1
78 4
LSL
1IX
88 3
PULX
1 INH
98 1
CLC
1 INH
A8 2
EOR
2 IMM
B8 3
EOR
2 DIR
C8 4
EOR
3 EXT
D8 4
EOR
3 IX2
E8 3
EOR
2IX1
F8 3
EOR
1IX
09 5
BRCLR4
3 DIR
19 5
BCLR4
2 DIR
29 3
BHCS
2 REL
39 5
ROL
2 DIR
49 1
ROLA
1 INH
59 1
ROLX
1 INH
69 5
ROL
2 IX1
79 4
ROL
1IX
89 2
PSHX
1 INH
99 1
SEC
1 INH
A9 2
ADC
2 IMM
B9 3
ADC
2 DIR
C9 4
ADC
3 EXT
D9 4
ADC
3 IX2
E9 3
ADC
2IX1
F9 3
ADC
1IX
0A 5
BRSET5
3 DIR
1A 5
BSET5
2 DIR
2A 3
BPL
2 REL
3A 5
DEC
2 DIR
4A 1
DECA
1 INH
5A 1
DECX
1 INH
6A 5
DEC
2 IX1
7A 4
DEC
1IX
8A 3
PULH
1 INH
9A 1
CLI
1 INH
AA 2
ORA
2 IMM
BA 3
ORA
2 DIR
CA 4
ORA
3 EXT
DA 4
ORA
3 IX2
EA 3
ORA
2IX1
FA 3
ORA
1IX
0B 5
BRCLR5
3 DIR
1B 5
BCLR5
2 DIR
2B 3
BMI
2 REL
3B 7
DBNZ
3 DIR
4B 4
DBNZA
2 INH
5B 4
DBNZX
2 INH
6B 7
DBNZ
3 IX1
7B 6
DBNZ
2IX
8B 2
PSHH
1 INH
9B 1
SEI
1 INH
AB 2
ADD
2 IMM
BB 3
ADD
2 DIR
CB 4
ADD
3 EXT
DB 4
ADD
3 IX2
EB 3
ADD
2IX1
FB 3
ADD
1IX
0C 5
BRSET6
3 DIR
1C 5
BSET6
2 DIR
2C 3
BMC
2 REL
3C 5
INC
2 DIR
4C 1
INCA
1 INH
5C 1
INCX
1 INH
6C 5
INC
2 IX1
7C 4
INC
1IX
8C 1
CLRH
1 INH
9C 1
RSP
1 INH
BC 3
JMP
2 DIR
CC 4
JMP
3 EXT
DC 4
JMP
3 IX2
EC 3
JMP
2IX1
FC 3
JMP
1IX
0D 5
BRCLR6
3 DIR
1D 5
BCLR6
2 DIR
2D 3
BMS
2 REL
3D 4
TST
2 DIR
4D 1
TSTA
1 INH
5D 1
TSTX
1 INH
6D 4
TST
2 IX1
7D 3
TST
1IX
9D 1
NOP
1 INH
AD 5
BSR
2 REL
BD 5
JSR
2 DIR
CD 6
JSR
3 EXT
DD 6
JSR
3 IX2
ED 5
JSR
2IX1
FD 5
JSR
1IX
0E 5
BRSET7
3 DIR
1E 5
BSET7
2 DIR
2E 3
BIL
2 REL
3E 6
CPHX
3 EXT
4E 5
MOV
3DD
5E 5
MOV
2 DIX+
6E 4
MOV
3IMD
7E 5
MOV
2 IX+D
8E 2+
STOP
1 INH
9E
Page 2 AE 2
LDX
2 IMM
BE 3
LDX
2 DIR
CE 4
LDX
3 EXT
DE 4
LDX
3 IX2
EE 3
LDX
2IX1
FE 3
LDX
1IX
0F 5
BRCLR7
3 DIR
1F 5
BCLR7
2 DIR
2F 3
BIH
2 REL
3F 5
CLR
2 DIR
4F 1
CLRA
1 INH
5F 1
CLRX
1 INH
6F 5
CLR
2 IX1
7F 4
CLR
1IX
8F 2+
WAIT
1 INH
9F 1
TXA
1 INH
AF 2
AIX
2 IMM
BF 3
STX
2 DIR
CF 4
STX
3 EXT
DF 4
STX
3 IX2
EF 3
STX
2IX1
FF 2
STX
1IX
INH Inherent REL Relative SP1 Stack Pointer, 8-Bit Offset
IMM Immediate IX Indexed, No Offset SP2 Stack Pointer, 16-Bit Offset
DIR Direct IX1 Indexed, 8-Bit Offset IX+ Indexed, No Offset with
EXT Extended IX2 Indexed, 16-Bit Offset Post Increment
DD DIR to DIR IMD IMM to DIR IX1+ Indexed, 1-Byte Offset with
IX+D IX+ to DIR DIX+ DIR to IX+ Post Increment Opcode in
Hexadecimal
Number of Bytes
F0 3
SUB
1IX
HCS08 Cycles
Instruction Mnemonic
Addressing Mode
Central Processor Unit (S08CPUV2)Central Processor Unit (S08CPUV2)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 105
Bit-Manipulation Branch Read-Modify-Write Control Register/Memory
9E60 6
NEG
3 SP1
9ED0 5
SUB
4 SP2
9EE0 4
SUB
3SP1
9E61 6
CBEQ
4 SP1
9ED1 5
CMP
4 SP2
9EE1 4
CMP
3SP1
9ED2 5
SBC
4 SP2
9EE2 4
SBC
3SP1
9E63 6
COM
3 SP1
9ED3 5
CPX
4 SP2
9EE3 4
CPX
3SP1
9EF3 6
CPHX
3 SP1
9E64 6
LSR
3 SP1
9ED4 5
AND
4 SP2
9EE4 4
AND
3SP1
9ED5 5
BIT
4 SP2
9EE5 4
BIT
3SP1
9E66 6
ROR
3 SP1
9ED6 5
LDA
4 SP2
9EE6 4
LDA
3SP1
9E67 6
ASR
3 SP1
9ED7 5
STA
4 SP2
9EE7 4
STA
3SP1
9E68 6
LSL
3 SP1
9ED8 5
EOR
4 SP2
9EE8 4
EOR
3SP1
9E69 6
ROL
3 SP1
9ED9 5
ADC
4 SP2
9EE9 4
ADC
3SP1
9E6A 6
DEC
3 SP1
9EDA 5
ORA
4 SP2
9EEA 4
ORA
3SP1
9E6B 8
DBNZ
4 SP1
9EDB 5
ADD
4 SP2
9EEB 4
ADD
3SP1
9E6C 6
INC
3 SP1
9E6D 5
TST
3 SP1
9EAE 5
LDHX
2IX
9EBE 6
LDHX
4 IX2
9ECE 5
LDHX
3 IX1
9EDE 5
LDX
4 SP2
9EEE 4
LDX
3SP1
9EFE 5
LDHX
3 SP1
9E6F 6
CLR
3 SP1
9EDF 5
STX
4 SP2
9EEF 4
STX
3SP1
9EFF 5
STHX
3 SP1
INH Inherent REL Relative SP1 Stack Pointer, 8-Bit Offset
IMM Immediate IX Indexed, No Offset SP2 Stack Pointer, 16-Bit Offset
DIR Direct IX1 Indexed, 8-Bit Offset IX+ Indexed, No Offset with
EXT Extended IX2 Indexed, 16-Bit Offset Post Increment
DD DIR to DIR IMD IMM to DIR IX1+ Indexed, 1-Byte Offset with
IX+D IX+ to DIR DIX+ DIR to IX+ Post Increment
Note: All Sheet 2 Opcodes are Preceded by the Page 2 Prebyte (9E) Prebyte (9E) and Opcode in
Hexadecimal
Number of Bytes
9E60 6
NEG
3 SP1
HCS08 Cycles
Instruction Mnemonic
Addressing Mode
Table 7-3. Opcode Map (Sheet 2 of 2)
Central Processor Unit (S08CPUV2)Central Processor Unit (S08CPUV2)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
106 Freescale Semiconductor
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 107
Chapter 8
Carrier Modulator Timer (S08CMTV1)
8.1 Introduction
Figure 8-1. MC9S08RC/RD/RE/RG Block Diagram
PTD3
PTD4/ACMP1–
PTD5/ACMP1+
PTD6/TPM1CH0
PTC1/KBI2P1
PTC0/KBI2P0
VSS
VDD
PTB3
PTB2
PTA7/KBI1P7–
PTB0/TxD1
PTB1/RxD1
PTD2/IRQ
PTD1/RESET
PTD0/BKGD/MS
PTC7/SS1
PTC6/SPSCK1
PTC5/MISO1
PTC4/MOSI1
PTC3/KBI2P3
PTC2/KBI2P2
PORT A
PORT C
PORT D
PORT B
8-BIT KEYBOARD
INTERRUPT MODULE (KBI1)
SERIAL PERIPHERAL
INTERFACE MODULE (SPI1)
USER FLASH
USER RAM
(RC/RD/RE/RG32/60 = 2048 BYTES)
DEBUG
MODULE (DBG)
(RC/RD/RE/RG60 = 63,364 BYTES)
HCS08 CORE
BDC
CPU
NOTES
NOTES 1, 5
2-CHANNEL TIMER/PWM
MODULE (TPM1)
PTE7–
PORT E
PTB5
PTB4
PTE6
PTB7/TPM1CH1
MODULE (ACMP1)
HCS08 SYSTEM CONTROL
RESETS AND INTERRUPTS
MODES OF OPERATION
POWER MANAGEMENT
VOLTAGE
REGULATOR
RTI
ANALOG COMPARATOR
COP
IRQ LVD
INTERNAL BUS
LOW-POWER OSCILLATOR
INTERFACE MODULE (SCI1)
SERIAL COMMUNICATIONS
7
PTA1/KBI1P1
8
PTE0
NOTE 1
NOTES1, 2, 6
NOTE 1
(RC/RD/RE/RG32 = 32,768 BYTES)
(RC/RD/RE8/16 = 1024 BYTES)
(RC/RD/RE16 = 16,384 BYTES)
XTAL
EXTAL
CARRIER MODULATOR
TIMER MODULE (CMT)
1, 3, 4
4-BIT KEYBOARD
INTERRUPT MODULE (KBI2)
IRO NOTE 5
PTA0/KBI1P0
(RC/RD/RE8 = 8192 BYTES)
NOTES:
1. Port pins are software configurable with pullup device if input port
2. PTA0 does not have a clamp diode to VDD. PTA0 should not be driven above VDD. Also, PTA0 does not pullup to VDD when internal
pullup is enabled.
3. IRQ pin contains software configurable pullup/pulldown device if IRQ enabled (IRQPE = 1)
4. The RESET pin contains integrated pullup device enabled if reset enabled (RSTPE = 1)
5. High current drive
6. Pins PTA[7:4] contain both pullup and pulldown devices. Pulldown enabled when KBI is enabled (KBIPEn = 1) and rising edge is
selected (KBEDGn = 1).
Carrier Modulator Transmitter (CMT) Block Description
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
108 Freescale Semiconductor
8.2 Features
The CMT consists of a carrier generator, modulator, and transmitter that drives the infrared out (IRO) pin.
The features of this module include:
• Four modes of operation
— Time with independent control of high and low times
— Baseband
— Frequency shift key (FSK)
— Direct software control of IRO pin
• Extended space operation in time, baseband, and FSK modes
• Selectable input clock divide: 1, 2, 4, or 8
• Interrupt on end of cycle
— Ability to disable IRO pin and use as timer interrupt
8.3 CMT Block Diagram
Figure 8-2. Carrier Modulator Transmitter Module Block Diagram
8.4 Pin Description
The IRO pin is the only pin associated with the CMT. The pin is driven by the transmitter output when the
MCGEN bit in the CMTMSC register and the IROPEN bit in the CMTOC register are set. If the MCGEN
bit is clear and the IROPEN bit is set, the pin is driven by the IROL bit in the CMTOC register. This enables
user software to directly control the state of the IRO pin by writing to the IROL bit. If the IROPEN bit is
clear, the pin is disabled and is not driven by the CMT module. This is so the CMT can be configured as a
modulo timer for generating periodic interrupts without causing pin activity.
CARRIER
GENERATOR MODULATOR
CARRIER
OUT (fCG)
MODULATOR
OUT TRANSMITTER
OUTPUT
BASE
FSK
PRIMARY/SECONDARY SELECT
CMT REGISTERS
IRO
PIN
EOC FLAG
EOC INT EN
MIREQ
AND BUS INTERFACE
BUS CLOCK
CMTCLK
CMTDIV
CLOCK
CONTROL
MCGEN
EXSPC
CMTPOL
CMTCG REGS
CMTCMD REGS
IROL
INTERNAL BUS IIREQ
IROPEN
Carrier Modulator Transmitter (CMT) Block Description
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 109
8.5 Functional Description
The CMT module consists of a carrier generator, a modulator, a transmitter output, and control registers.
The block diagram is shown in Figure 8-2. When operating in time mode, the user independently defines
the high and low times of the carrier signal to determine both period and duty cycle. The carrier generator
resolution is 125 ns when operating with an 8 MHz internal bus frequency and the CMTDIV1 and
CMTDIV0 bits in the CMTMSC register are both equal to 0. The carrier generator can generate signals
with periods between 250 ns (4 MHz) and 127.5 µs (7.84 kHz) in steps of 125 ns. See Table 8-1.
The possible duty cycle options will depend upon the number of counts required to complete the carrier
period. For example, a 1.6 MHz signal has a period of 625 ns and will therefore require 5 ×125 ns counts
to generate. These counts may be split between high and low times, so the duty cycles available will be
20 percent (one high, four low), 40 percent (two high, three low), 60 percent (three high, two low) and
80 percent (four high, one low).
For lower frequency signals with larger periods, higher resolution (as a percentage of the total period) duty
cycles are possible.
When the BASE bit in the CMT modulator status and control register (CMTMSC) is set, the carrier output
(fCG) to the modulator is held high continuously to allow for the generation of baseband protocols.
A third mode allows the carrier generator to alternate between two sets of high and low times. When
operating in FSK mode, the generator will toggle between the two sets when instructed by the modulator,
allowing the user to dynamically switch between two carrier frequencies without CPU intervention.
The modulator provides a simple method to control protocol timing. The modulator has a minimum
resolution of 1.0 µs with an 8 MHz internal bus clock. It can count bus clocks (to provide real-time control)
or it can count carrier clocks (for self-clocked protocols). See Section 8.5.2, “Modulator," for more details.
The transmitter output block controls the state of the infrared out pin (IRO). The modulator output is gated
on to the IRO pin when the modulator/carrier generator is enabled.
A summary of the possible modes is shown in Table 8-2.
Table 8-1. Clock Divide
Bus
Clock
(MHz)
CMTDIV1:CMTDIV0
Carrier
Generator
Resolution
(µs)
Min Carrier
Generator
Period
(µs)
Min
Modulator
Period
(µs)
8 0:0 0.125 0.25 1.0
8 0:1 0.25 0.5 2.0
8 1:0 0.5 1.0 4.0
8 1:1 1.0 2.0 8.0
Carrier Modulator Transmitter (CMT) Block Description
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
110 Freescale Semiconductor
8.5.1 Carrier Generator
The carrier signal is generated by counting a register-selected number of input clocks (125 ns for an 8 MHz
bus) for both the carrier high time and the carrier low time. The period is determined by the total number
of clocks counted. The duty cycle is determined by the ratio of high time clocks to total clocks counted.
The high and low time values are user programmable and are held in two registers.
An alternate set of high/low count values is held in another set of registers to allow the generation of dual
frequency FSK (frequency shift keying) protocols without CPU intervention.
NOTE
Only non-zero data values are allowed. The carrier generator will not work
if any of the count values are equal to zero.
The MCGEN bit in the CMTMSC register must be set and the BASE bit must be cleared to enable carrier
generator clocks. When the BASE bit is set, the carrier output to the modulator is held high continuously.
The block diagram is shown in Figure 8-3.
Table 8-2. CMT Modes of Operation
Mode MCGEN
Bit(1)
1. To prevent spurious operation, initialize all data and control registers before beginning a transmission (MCGEN=1).
BASE
Bit(2)
2. These bits are not double buffered and should not be changed during a transmission (while MCGEN=1).
FSK
Bit(2) EXSPC
Bit Comment
Time 1 0 0 0 fCG controlled by primary high and low registers.
fCG transmitted to IRO pin when modulator gate is open.
Baseband 1 1 x 0 fCG is always high. IRO pin high when modulator gate is open.
FSK 1 0 1 0
fCG control alternates between primary high/low registers and
secondary high/low registers.
fCG transmitted to IRO pin when modulator gate is open.
Extended
Space 1xx1
Setting the EXSPC bit causes subsequent modulator cycles
to be spaces (modulator out not asserted) for the duration of
the modulator period (mark and space times).
IRO Latch 0 x x x IROL bit controls state of IRO pin.
Carrier Modulator Transmitter (CMT) Block Description
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 111
Figure 8-3. Carrier Generator Block Diagram
The high/low time counter is an 8-bit up counter. After each increment, the contents of the counter are
compared with the appropriate high or low count value register. When the compare value is reached, the
counter is reset to a value of $01, and the compare is redirected to the other count value register.
Assuming that the high time count compare register is currently active, a valid compare will cause the
carrier output to be driven low. The counter will continue to increment (starting at reset value of $01).
When the value stored in the selected low count value register is reached, the counter will again be reset
and the carrier output will be driven high.
The cycle repeats, automatically generating a periodic signal that is directed to the modulator. The lowest
frequency (maximum period) and highest frequency (minimum period) that can be generated are defined
as:
fmax = fCMTCLK ÷ (2 x 1) Hz Eqn. 8-1
fmin = fCMTCLK ÷ (2 x (28 – 1)) Hz Eqn. 8-2
In the general case, the carrier generator output frequency is:
fCG = fCMTCLK ÷(Highcount + Lowcount) Hz Eqn. 8-3
Where: 0 < Highcount < 256 and
0 < Lowcount < 256
CLK 8-BIT UP COUNTER
=?
=?
CLR
CLOCK AND OUTPUT CONTROL
CMTCGH1
CMTCGH2
PRIMARY/
SELECT
CARRIER OUT (fCG)
SECONDARY
CMTCGL2
CMTCGL1
CMTCLK
BASE
FSK
MCGEN
Carrier Modulator Transmitter (CMT) Block Description
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
112 Freescale Semiconductor
The duty cycle of the carrier signal is controlled by varying the ratio of high time to low + high time. As
the input clock period is fixed, the duty cycle resolution will be proportional to the number of counts
required to generate the desired carrier period.
8.5.2 Modulator
The modulator has three main modes of operation:
• Gate the carrier onto the modulator output (time mode)
• Control the logic level of the modulator output (baseband mode)
• Count carrier periods and instruct the carrier generator to alternate between two carrier frequencies
whenever a modulation period (mark + space counts) expires (FSK mode)
The modulator includes a 17-bit down counter with underflow detection. The counter is loaded from the
16-bit modulation mark period buffer registers, CMTCMD1 and CMTCMD2. The most significant bit is
loaded with a logic zero and serves as a sign bit. When the counter holds a positive value, the modulator
gate is open and the carrier signal is driven to the transmitter block.
When the counter underflows, the modulator gate is closed and a 16-bit comparator is enabled that
compares the logical complement of the value of the down-counter with the contents of the modulation
space period register (which has been loaded from the registers CMTCMD3 and CMTCMD4).
When a match is obtained the cycle repeats by opening the modulator gate, reloading the counter with the
contents of CMTCMD1 and CMTCMD2, and reloading the modulation space period register with the
contents of CMTCMD3 and CMTCMD4.
If the contents of the modulation space period register are all zeroes, the match will be immediate and no
space period will be generated (for instance, for FSK protocols that require successive bursts of different
frequencies).
The MCGEN bit in the CMTMSC register must be set to enable the modulator timer.
Duty Cycle Highcount
Highcount Lowcount+
---------------------------------------------------------------------=Eqn. 8-
4
Carrier Modulator Transmitter (CMT) Block Description
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 113
Figure 8-4. Modulator Block Diagram
8.5.2.1 Time Mode
When the modulator operates in time mode (MCGEN bit is set, BASE bit is clear, and FSK bit is clear),
the modulation mark period consists of an integer number of CMTCLK ÷8 clock periods. The modulation
space period consists of zero or an integer number of CMTCLK ÷8 clock periods. With an 8 MHz bus and
CMTDIV1:CMTDIV0 = 00, the modulator resolution is 1 µs and has a maximum mark and space period
of about 65.535 ms each. See Figure 8-5 for an example of the time mode and baseband mode outputs.
The mark and space time equations for time and baseband mode are:
tmark = (CMTCMD1:CMTCMD2 + 1) ÷ (fCMTCLK ÷ 8) Eqn. 8-5
tspace = CMTCMD3:CMTCMD4 ÷ (fCMTCLK ÷ 8) Eqn. 8-6
where CMTCMD1:CMTCMD2 and CMTCMD3:CMTCMD4 are the decimal values of the concatenated
registers.
NOTE
If the modulator is disabled while the tmark time is less than the programmed
carrier high time (tmark < CMTCGH1/fCMTCLK), the modulator can enter
into an illegal state and end the curent cycle before the programmed value.
Make sure to program tmark greater than the carrier high time to avoid this
illegal state.
=?
0
COUNTER
CMTCLOCK
CMTCMD1:CMTCMD2
CMTCMD3:CMTCMD4
SPACE PERIOD REGISTER *
17-BIT DOWN COUNTER *
* DENOTES HIDDEN REGISTER
16 BITS
16 BITS
MS BIT
16
16
MODULE INTERRUPT REQUEST
÷8
CLOCK CONTROL
CARRIER OUT (fCG)
LOAD
SYSTEM CONTROL
EOC FLAG SET
MODULATOR GATE OUT
PRIMARY/SECONDARY SELECT
.
.
MODULATOR
EXSPC
MODE
EOCIE
BASE
FSK
Carrier Modulator Transmitter (CMT) Block Description
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
114 Freescale Semiconductor
Figure 8-5. Example CMT Output in Time and Baseband Modes
8.5.2.2 Baseband Mode
Baseband mode (MCGEN bit is set and BASE bit is set) is a derivative of time mode, where the mark and
space period is based on (CMTCLK ÷8) counts. The mark and space calculations are the same as in time
mode. In this mode the modulator output will be at a logic 1 for the duration of the mark period and at a
logic 0 for the duration of a space period. See Figure 8-5 for an example of the output for both baseband
and time modes. In the example, the carrier out frequency (fCG) is generated with a high count of $01 and
a low count of $02, which results in a divide of 3 of CMTCLK with a 33 percent duty cycle. The modulator
down-counter was loaded with the value $0003 and the space period register with $0002.
NOTE
The waveforms in Figure 8-5 and Figure 8-6 are for the purpose of
conceptual illustration and are not meant to represent precise timing
relationships between the signals shown.
8.5.2.3 FSK Mode
When the modulator operates in FSK mode (MCGEN bit is set, FSK bit is set, and BASE bit is clear), the
modulation mark and space periods consist of an integer number of carrier clocks (space period can be 0).
When the mark period expires, the space period is transparently started (as in time mode). The carrier
generator toggles between primary and secondary data register values whenever the modulator space
period expires.
MODULATOR GATE
CMTCLK ÷ 8
IRO PIN (TIME MODE)
IRO PIN
MARK SPACE MARK
CARRIER OUT(fCG)
(BASEBAND MODE)
Carrier Modulator Transmitter (CMT) Block Description
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 115
The space period provides an interpulse gap (no carrier). If CMTCMD3:CMTCMD4 = $0000, then the
modulator and carrier generator will switch between carrier frequencies without a gap or any carrier
glitches (zero space).
Using timing data for carrier burst and interpulse gap length calculated by the CPU, FSK mode can
automatically generate a phase-coherent, dual-frequency FSK signal with programmable burst and
interburst gaps.
The mark and space time equations for FSK mode are:
tmark = (CMTCMD1:CMTCMD2 + 1) ÷fCG Eqn. 8-7
tspace = CMTCMD3:CMTCMD4 ÷fCG Eqn. 8-8
Where fCG is the frequency output from the carrier generator. The example in Figure 8-6 shows what the
IRO pin output looks like in FSK mode with the following values: CMTCMD1:CMTCMD2 = $0003,
CMTCMD3:CMTCMD4 = $0002, primary carrier high count = $01, primary carrier low count = $02,
secondary carrier high count = $03, and secondary carrier low count = $01.
Figure 8-6. Example CMT Output in FSK Mode
8.5.3 Extended Space Operation
In time, baseband, or FSK mode, the space period can be made longer than the maximum possible value
of the space period register. Setting the EXSPC bit in the CMTMSC register will force the modulator to
treat the next modulation period (beginning with the next load of the counter and space period register) as
a space period equal in length to the mark and space counts combined. Subsequent modulation periods will
consist entirely of these extended space periods with no mark periods. Clearing EXSPC will return the
modulator to standard operation at the beginning of the next modulation period.
8.5.3.1 EXSPC Operation in Time Mode
To calculate the length of an extended space in time or baseband modes, add the mark and space times and
multiply by the number of modulation periods that EXSPC is set.
MARK1 SPACE1 MARK2 SPACE2 MARK1 SPACE1 MARK2
MODULATOR GATE
CARRIER OUT (fCG)
IRO PIN
Carrier Modulator Transmitter (CMT) Block Description
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
116 Freescale Semiconductor
texspace = tspace + (tmark + tspace) x (number of modulation periods) Eqn. 8-9
For an example of extended space operation, see Figure 8-7.
NOTE
The EXSPC feature can be used to emulate a zero mark event.
Figure 8-7. Extended Space Operation
8.5.3.2 EXSPC Operation in FSK Mode
In FSK mode, the modulator continues to count carrier out clocks, alternating between the primary and
secondary registers at the end of each modulation period.
To calculate the length of an extended space in FSK mode, the user must know whether the EXSPC bit
was set on a primary or secondary modulation period, as well as the total number of both primary and
secondary modulation periods completed while the EXSPC bit is high. A status bit for the current
modulation is not accessible to the CPU. If necessary, software should maintain tracking of the current
modulation cycle (primary or secondary). The extended space period ends at the completion of the space
period time of the modulation period during which the EXSPC bit is cleared.
If the EXSPC bit was set during a primary modulation cycle, use the equation:
texspace = (tspace)p + (tmark + tspace)s + (tmark + tspace)p+... Eqn. 8-10
Where the subscripts p and s refer to mark and space times for the primary and secondary modulation
cycles.
If the EXSPC bit was set during a secondary modulation cycle, use the equation:
texspace = (tspace)s + (tmark + tspace)p + (tmark + tspace)s+... Eqn. 8-11
8.5.4 Transmitter
The transmitter output block controls the state of the infrared out pin (IRO). The modulator output is gated
on to the IRO pin when the modulator/carrier generator is enabled. When the modulator/carrier generator
is disabled, the IRO pin is controlled by the state of the IRO latch.
A polarity bit in the CMTOC register enables the IRO pin to be high true or low true.
SET EXSPC CLEAR EXSPC
Carrier Modulator Transmitter (CMT) Block Description
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 117
8.5.5 CMT Interrupts
The end of cycle flag (EOCF) is set when:
• The modulator is not currently active and the MCGEN bit is set to begin the initial CMT
transmission
• At the end of each modulation cycle (when the counter is reloaded from CMTCMD1:CMTCMD2)
while the MCGEN bit is set
In the case where the MCGEN bit is cleared and then set before the end of the modulation cycle, the EOCF
bit will not be set when the MCGEN is set, but will become set at the end of the current modulation cycle.
When the MCGEN becomes disabled, the CMT module does not set the EOC flag at the end of the last
modulation cycle.
The EOCF bit is cleared by reading the CMT modulator status and control register (CMTMSC) followed
by an access of CMTCMD2 or CMTCMD4.
If the EOC interrupt enable (EOCIE) bit is high when the EOCF bit is set, the CMT module will generate
an interrupt request. The EOCF bit must be cleared within the interrupt service routine to prevent another
interrupt from being generated after exiting the interrupt service routine.
The EOC interrupt is coincident with loading the down-counter with the contents of
CMTCMD1:CMTCMD2 and loading the space period register with the contents of
CMTCMD3:CMTCMD4. The EOC interrupt provides a means for the user to reload new mark/space
values into the modulator data registers. Modulator data register updates will take effect at the end of the
current modulation cycle. Note that the down-counter and space period register are updated at the end of
every modulation cycle, regardless of interrupt handling and the state of the EOCF flag.
8.5.6 Wait Mode Operation
During wait mode the CMT, if enabled, will continue to operate normally. However, there will be no new
codes or changes of pattern mode while in wait mode, because the CPU is not operating.
8.5.7 Stop Mode Operation
During all stop modes, clocks to the CMT module are halted.
In stop1 and stop2 modes, all CMT register data is lost and must be re-initialized upon recovery from these
two stop modes.
No CMT module registers are affected in stop3 mode.
Note, because the clocks are halted, the CMT will resume upon exit from stop (only in stop3 mode).
Software should ensure stop2 or stop3 mode is not entered while the modulator is in operation to prevent
the IRO pin from being asserted while in stop mode. This may require a time-out period from the time that
the MCGEN bit is cleared to allow the last modulator cycle to complete.
Carrier Modulator Transmitter (CMT) Block Description
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
118 Freescale Semiconductor
8.5.8 Background Mode Operation
When the microcontroller is in active background mode, the CMT temporarily suspends all counting until
the microcontroller returns to normal user mode.
8.6 CMT Registers and Control Bits
The following registers control and monitor CMT operation:
• CMT carrier generator data registers (CMTCGH1, CMTCGL1, CMTCGH2, CMTCGL2)
• CMT output control register (CMTOC)
• CMT modulator status and control register (CMTMSC)
• CMT modulator period data registers (CMTCMD1, CMTCMD2, CMTCMD3, CMTCMD4)
8.6.1 Carrier Generator Data Registers (CMTCGH1, CMTCGL1,
CMTCGH2, and CMTCGL2)
The carrier generator data registers contain the primary and secondary high and low values for generating
the carrier output.
76543210
R
PH7 PH6 PH5 PH4 PH3 PH2 PH1 PH0
W
Reset uuuuuuuu
u = Unaffected
Figure 8-8. Carrier Generator Data Register High 1(CMTCGH1)
Table 8-3. CMTCGH1 Field Descriptions
Field Description
7:0
PH[7:0]
Primary Carrier High Time Data Values — When selected, these bits contain the number of input clocks
required to generate the carrier high and low time periods. When operating in time mode (see Section 8.5.2.1,
“Time Mode”), this register pair is always selected. When operating in FSK mode (see Section 8.5.2.3, “FSK
Mode”), this register pair and the secondary register pair are alternatively selected under control of the
modulator. The primary carrier high and low time values are unaffected out of reset. These bits must be written
to nonzero values before the carrier generator is enabled to avoid spurious results.
Carrier Modulator Transmitter (CMT) Block Description
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 119
76543210
R
PL7 PL6 PL5 PL4 PL3 PL2 PL1 PL0
W
Reset uuuuuuuu
u = Unaffected
Figure 8-9. Carrier Generator Data Register Low 1 (CMTCGL1)
Table 8-4. CMTCGL1 Field Descriptions
Field Description
7:0
PL[7:0]
Primary Carrier Low Time Data Values — When selected, these bits contain the number of input clocks
required to generate the carrier high and low time periods. When operating in time mode (see Section 8.5.2.1,
“Time Mode”), this register pair is always selected. When operating in FSK mode (see Section 8.5.2.3, “FSK
Mode”), this register pair and the secondary register pair are alternatively selected under control of the
modulator. The primary carrier high and low time values are unaffected out of reset. These bits must be written
to nonzero values before the carrier generator is enabled to avoid spurious results.
76543210
R
SH7 SH6 SH5 SH4 SH3 SH2 SH1 SH0
W
Reset uuuuuuuu
u = Unaffected
Figure 8-10. Carrier Generator Data Register High 2 (CMTCGH2)
Table 8-5. CMTCGH2 Field Descriptions
Field Description
7:0
SH[7:0]
Secondary Carrier High Time Data Values — When selected, these bits contain the number of input clocks
required to generate the carrier high and low time periods. When operating in time mode (see Section 8.5.2.1,
“Time Mode"), this register pair is never selected. When operating in FSK mode (see Section 8.5.2.3, “FSK
Mode"), this register pair and the primary register pair are alternatively selected under control of the modulator.
The secondary carrier high and low time values are unaffected out of reset. These bits must be written to nonzero
values before the carrier generator is enabled when operating in FSK mode.
Carrier Modulator Transmitter (CMT) Block Description
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
120 Freescale Semiconductor
8.6.2 CMT Output Control Register (CMTOC)
This register is used to control the IRO output of the CMT module.
76543210
R
SL7 SL6 SL5 SL4 SL3 SL2 SL1 SL0
W
Reset uuuuuuuu
u = Unaffected
Figure 8-11. Carrier Generator Data Register Low 2 (CMTCGL2)
Table 8-6. CMTCGL2 Field Descriptions
Field Description
7:0
SL[7:0]
Secondary Carrier Low Time Data Values — When selected, these bits contain the number of input clocks
required to generate the carrier high and low time periods. When operating in time mode (see Section 8.5.2.1,
“Time Mode"), this register pair is never selected. When operating in FSK mode (see Section 8.5.2.3, “FSK
Mode"), this register pair and the primary register pair are alternatively selected under control of the modulator.
The secondary carrier high and low time values are unaffected out of reset. These bits must be written to nonzero
values before the carrier generator is enabled when operating in FSK mode.
76543210
R
IROL CMTPOL IROPEN
00000
W
Reset 00000000
= Unimplemented or Reserved
Figure 8-12. CMT Output Control Register (CMTOC)
Table 8-7. CMTOC Field Descriptions
Field Description
7
IROL
IRO Latch Control — Reading IROL reads the state of the IRO latch. Writing IROL changes the state of the IRO
pin when the MCGEN bit is clear in the CMTMSC register and the IROPEN bit is set.
6
CMTPOL
CMT Output Polarity — The CMTPOL bit controls the polarity of the IRO pin output of the CMT.
0 IRO pin is active low
1 IRO pin is active high
5
IROPEN
IRO Pin Enable — The IROPEN bit is used to enable and disable the IRO pin. When the pin is enabled, it is an
output that drives out either the CMT transmitter output or the state of the IROL bit depending on whether the
MCGEN bit in the CMTMSC register is set. Also, the state of the output is either inverted or not depending on
the state of the CMTPOL bit. When the pin is disabled, it is in a high impedance state so it doesn’t draw any
current. The pin is disabled during reset.
0 IRO pin disabled
1 IRO pin enabled as output
Carrier Modulator Transmitter (CMT) Block Description
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 121
8.6.3 CMT Modulator Status and Control Register (CMTMSC)
The CMT modulator status and control register (CMTMSC) contains the modulator and carrier generator
enable (MCGEN), end of cycle interrupt enable (EOCIE), FSK mode select (FSK), baseband enable
(BASE), extended space (EXSPC), prescaler (CMTDIV1:CMTDIV0) bits, and the end of cycle (EOCF)
status bit.
76543210
R EOCF
CMTDIV1 CMTDIV0 EXSPC BASE FSK EOCIE MCGEN
W
Reset 00000000
= Unimplemented or Reserved
Figure 8-13. CMT Modulator Status and Control Register (CMTMSC)
Table 8-8. CMTMSC Field Descriptions
Field Description
7
EOCF
End of Cycle Status Flag — The EOCF bit is set when:
• The modulator is not currently active and the MCGEN bit is set to begin the initial CMT transmission.
• At the end of each modulation cycle while the MCGEN bit is set. This is recognized when a match occurs
between the contents of the space period register and the down-counter. At this time, the counter is
initialized with the (possibly new) contents of the mark period buffer, CMTCMD1 and CMTCMD2. The
space period register is loaded with the (possibly new) contents of the space period buffer, CMTCMD3 and
CMTCMD4.
This flag is cleared by a read of the CMTMSC register followed by an access of CMTCMD2 or CMTCMD4.
In the case where the MCGEN bit is cleared and then set before the end of the modulation cycle, EOCF will not
be set when MCGEN is set, but will be set at the end of the current modulation cycle.
0 No end of modulation cycle occurrence since flag last cleared
1 End of modulator cycle has occurred
6:5
CMTDIV[1:0]
CMT Clock Divide Prescaler — The CMT clock divide prescaler causes the CMT to be clocked at the BUS
CLOCK frequency, or the BUS CLOCK frequency divided by 1, 2, 4, or 8. Because these bits are not double
buffered, they should not be changed during a transmission.
00 Bus clock ÷1
01 Bus clock ÷2
10 Bus clock ÷ 4
11 Bus clock ÷ 8
4
EXSPC
Extended Space Enable — The EXSPC bit enables extended space operation.
0 Extended space disabled
1 Extended space enabled
3
BASE
Baseband Enable — When set, the BASE bit disables the carrier generator and forces the carrier output high
for generation of baseband protocols. When BASE is clear, the carrier generator is enabled and the carrier output
toggles at the frequency determined by values stored in the carrier data registers. See Section 8.5.2.2,
“Baseband Mode." This bit is cleared by reset. This bit is not double buffered and should not be written to during
a transmission.
0 Baseband mode disabled
1 Baseband mode enabled
2
FSK
FSK Mode Select — The FSK bit enables FSK operation.
0 CMT operates in time or baseband mode
1 CMT operates in FSK mode
Carrier Modulator Transmitter (CMT) Block Description
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
122 Freescale Semiconductor
8.6.4 CMT Modulator Data Registers (CMTCMD1, CMTCMD2, CMTCMD3,
and CMTCMD4)
The modulator data registers control the mark and space periods of the modulator for all modes. The
contents of these registers are transferred to the modulator down counter and space period register upon
the completion of a modulation period.
1
EOCIE
End of Cycle Interrupt Enable — A CPU interrupt will be requested when EOCF is set if EOCIE is high.
0 CPU interrupt disabled
1 CPU interrupt enabled
0
MCGEN
Modulator and Carrier Generator Enable — Setting MCGEN will initialize the carrier generator and modulator
and enable all clocks. After it is enabled, the carrier generator and modulator will function continuously. When
MCGEN is cleared, the current modulator cycle will be allowed to expire before all carrier and modulator clocks
are disabled (to save power) and the modulator output is forced low. To prevent spurious operation, the user
should initialize all data and control registers before enabling the system.
0 Modulator and carrier generator disabled
1 Modulator and carrier generator enabled
Table 8-9. Sample Register Summary
Name 76543210
CMTCMD1 R
MB15 MB14 MB13 MB12 MB11 MB10 MB9 MB8
W
CMTCMD2 R
MB7 MB6 MB5 MB4 MB3 MB2 MB1 MB0
W
CMTCMD3 R
SB15 SB14 SB13 SB12 SB11 SB10 SB9 SB8
W
CMTCMD4 R
SB7 SB6 SB5 SB4 SB3 SB2 SB1 SB0
W
Table 8-8. CMTMSC Field Descriptions (continued)
Field Description
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 123
Chapter 9
Keyboard Interrupt (S08KBIV1)
9.1 Introduction
The MC9S08RC/RD/RE/RG has two KBI modules. One has eight keyboard interrupt inputs that share
port A pins. The other KBI module has four inputs that are shared on the upper four pins of port C. See the
Pins and Connections chapter for more information about the logic and hardware aspects of these pins.
Port A is an 8-bit port that is shared between the KBI1 keyboard interrupt inputs and general-purpose I/O.
The eight KBI1PEn control bits in the KBI1PE register allow selection of any combination of port A pins
to be assigned as KBI1 inputs. Any pins that are enabled as KBI1 inputs will be forced to act as inputs and
the remaining port A pins are available as general-purpose I/O pins controlled by the port A data (PTAD),
data direction (PTADD) and pullup enable (PTAPE) registers. The eight PTAPEn control bits in the
PTAPE register allow the user to select whether an internal pullup device is enabled on each port A pin
that is configured as a port input or a KBI1 input.
KBI1 inputs can be configured for edge-only sensitivity or edge-and-level sensitivity. Bits 3 through 0 of
port A are falling-edge/low-level sensitive and bits 7 through 4 can be configured for
rising-edge/high-level or for falling-edge/low-level sensitivity.
Port C is an 8-bit port with its lower four pins shared between the KBI2 keyboard interrupt inputs and
general-purpose I/O. The four KBI2PEn control bits in the KBI2PE register allow selection of any
combination of the lower four port C pins to be assigned as KBI2 inputs. Any pins that are enabled as KBI2
inputs will be forced to act as inputs and the remaining port C pins are available as general-purpose I/O
pins controlled by the port C data (PTCD), data direction (PTCDD) and pullup enable (PTCPE) registers.
The eight PTCPEn control bits in the PTCPE register allow the user to select whether an internal pullup
device is enabled on each port C pin that is configured as a port input or a KBI2 input.
Any enabled keyboard interrupt can be used to wake the MCU from wait, standby (stop3), partial
power-down (stop2) or power-down modes (stop1). In either stop1 or stop2 mode, an input functions as a
falling edge/low-level wakeup, therefore it should be configured to use falling-edge sensing if the MCU
will be used in stop1 or stop2 modes.
Either KBI1 or KBI2 can be used to wake the MCU from wait or standby (stop3). Only KBI1 can be used
to wake the MCU from partial power down (stop2) or power down (stop1). When using KBI1 to wake up
from stop2 or stop1, the pins must be configured to use falling-edge/low-level sensing (KBEDG = 0). The
KBF bits for both KBI modules must be cleared before entering stop mode, regardless of whether the
interrupt is enabled.
NOTE
The voltage measured on the pulled up PTA0 pin will be less than VDD. The
internal gates connected to this pin are pulled all the way to VDD. All other
pins with enabled pullup resistors will have an unloaded measurement of
VDD.
Keyboard Interrupt (S08KBIV1)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
124 Freescale Semiconductor
Figure 9-1. MC9S08RC/RD/RE/RG Block Diagram
PTD3
PTD4/ACMP1–
PTD5/ACMP1+
PTD6/TPM1CH0
PTC1/KBI2P1
PTC0/KBI2P0
VSS
VDD
PTB3
PTB2
PTA7/KBI1P7–
PTB0/TxD1
PTB1/RxD1
PTD2/IRQ
PTD1/RESET
PTD0/BKGD/MS
PTC7/SS1
PTC6/SPSCK1
PTC5/MISO1
PTC4/MOSI1
PTC3/KBI2P3
PTC2/KBI2P2
PORT A
PORT C
PORT D
PORT B
8-BIT KEYBOARD
INTERRUPT MODULE (KBI1)
SERIAL PERIPHERAL
INTERFACE MODULE (SPI1)
USER FLASH
USER RAM
(RC/RD/RE/RG32/60 = 2048 BYTES)
DEBUG
MODULE (DBG)
(RC/RD/RE/RG60 = 63,364 BYTES)
HCS08 CORE
NOTES
NOTES 1, 5
2-CHANNEL TIMER/PWM
MODULE (TPM1)
PTE7–
PORT E
PTB5
PTB4
PTE6
PTB7/TPM1CH1
MODULE (ACMP1)
HCS08 SYSTEM CONTROL
RESETS AND INTERRUPTS
MODES OF OPERATION
POWER MANAGEMENT
VOLTAGE
REGULATOR
RTI
ANALOG COMPARATOR
COP
IRQ LVD
INTERNAL BUS
LOW-POWER OSCILLATOR
INTERFACE MODULE (SCI1)
SERIAL COMMUNICATIONS
7
PTA1/KBI1P1
8
PTE0
NOTE 1
NOTES1, 2
NOTE 1
(RC/RD/RE/RG32 = 32,768 BYTES)
(RC/RD/RE8/16 = 1024 BYTES)
(RC/RD/RE16 = 16,384 BYTES)
XTAL
EXTAL
CARRIER MODULATOR
TIMER MODULE (CMT)
1, 3, 4
4-BIT KEYBOARD
INTERRUPT MODULE (KBI2)
IRO NOTE 5
PTA0/KBI1P0
(RC/RD/RE8 = 8192 BYTES)
BDC
CPU
NOTES:
7. Port pins are software configurable with pullup device if input port
8. PTA0 does not have a clamp diode to VDD. PTA0 should not be driven above VDD. Also, PTA0 does not pullup to VDD when internal
pullup is enabled.
9. IRQ pin contains software configurable pullup/pulldown device if IRQ enabled (IRQPE = 1)
10.The RESET pin contains integrated pullup device enabled if reset enabled (RSTPE = 1)
11.High current drive
12.Pins PTA[7:4] contain both pullup and pulldown devices. Pulldown enabled when KBI is enabled (KBIPEn = 1) and rising edge is
selected (KBEDGn = 1).
Keyboard Interrupt (KBI) Block Description
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 125
9.2 KBI Block Diagram
Figure 9-2 shows the block diagram for a KBI module.
Figure 9-2. KBI Block Diagram
The KBI module allows up to eight pins to act as additional interrupt sources. Four of these pins allow
falling-edge sensing while the other four can be configured for either rising-edge sensing or falling-edge
sensing. The sensing mode for all eight pins can also be modified to detect edges and levels instead of only
edges.
9.3 Keyboard Interrupt (KBI) Module
This on-chip peripheral module is called a keyboard interrupt (KBI) module because originally it was
designed to simplify the connection and use of row-column matrices of keyboard switches. However, these
inputs are also useful as extra external interrupt inputs and as an external means of waking up the MCU
from stop or wait low-power modes.
9.3.1 Pin Enables
The KBIPEn control bits in the KBIxPE register allow a user to enable (KBIPEn = 1) any combination of
KBI-related port pins to be connected to the KBI module. Pins corresponding to 0s in KBIxPE are
general-purpose I/O pins that are not associated with the KBI module.
9.3.2 Edge and Level Sensitivity
Synchronous logic is used to detect edges. Prior to detecting an edge, enabled keyboard inputs in a KBI
module must be at the deasserted logic level.
A falling edge is detected when an enabled keyboard input signal is seen as a logic 1 (the deasserted level)
during one bus cycle and then a logic 0 (the asserted level) during the next cycle.
KEYBOARD
INTERRUPT
DQ
CK
CLR
VDD
KBIMOD
KBIE
KEYBOARD
INTERRUPT FF
REQUEST
KBACK
RESET
SYNCHRONIZER
KBF
STOP BYPASS
STOP
BUSCLK
KBIPEn
0
1
S
KBEDGn
KBIPE0
KBIPE3
KBIPE4
0
1
S
KBEDG4
KBIxP0
KBIxP3
KBIxP4
KBIxPn
Keyboard Interrupt (KBI) Block Description
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
126 Freescale Semiconductor
A rising edge is detected when the input signal is seen as a logic 0 during one bus cycle and then a logic 1
during the next cycle.
The KBIMOD control bit can be set to reconfigure the detection logic so that it detects edges and levels.
In KBIMOD = 1 mode, the KBF status flag becomes set when an edge is detected (when one or more
enabled pins change from the deasserted to the asserted level while all other enabled pins remain at their
deasserted levels), but the flag is continuously set (and cannot be cleared) as long as any enabled keyboard
input pin remains at the asserted level. When the MCU enters stop mode, the synchronous edge-detection
logic is bypassed (because clocks are stopped). In stop mode, KBI inputs act as asynchronous
level-sensitive inputs so they can wake the MCU from stop mode.
9.3.3 KBI Interrupt Controls
The KBF status flag becomes set (1) when an edge event has been detected on any KBI input pin. If
KBIE = 1 in the KBIxSC register, a hardware interrupt will be requested whenever KBF = 1. The KBF flag
is cleared by writing a 1 to the keyboard acknowledge (KBACK) bit.
When KBIMOD = 0 (selecting edge-only operation), KBF is always cleared by writing 1 to KBACK.
When KBIMOD = 1 (selecting edge-and-level operation), KBF cannot be cleared as long as any keyboard
input is at its asserted level.
9.4 KBI Registers and Control Bits
This section provides information about all registers and control bits associated with the KBI modules.
Refer to the direct-page register summary in the Memory chapter of this data sheet for the absolute address
assignments for all KBI registers. This section refers to registers and control bits only by their names. A
Freescale-provided equate or header file is used to translate these names into the appropriate absolute
addresses.
Some MCU systems have more than one KBI, so register names include placeholder characters to identify
which KBI is being referenced. For example, KBIxSC refers to the KBIx status and control register and
KBI2SC is the status and control register for KBI2.
Keyboard Interrupt (KBI) Block Description
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 127
9.4.1 KBI x Status and Control Register (KBIxSC)
76543210
R
KBEDG7 KBEDG6 KBEDG5 KBEDG4
KBF 0
KBIE KBIMOD
W KBACK
Reset 00000000
= Unimplemented or Reserved
Figure 9-3. KBI x Status and Control Register (KBIxSC)
Table 9-1. KBIxSC Field Descriptions
Field Description
7:4
KBEDG[7:4]
Keyboard Edge Select for KBI Port Bits — Each of these read/write bits selects the polarity of the edges and/or
levels that are recognized as trigger events on the corresponding KBI port pin when it is configured as a keyboard
interrupt input (KBIPEn = 1). Also see the KBIMOD control bit, which determines whether the pin is sensitive to
edges-only or edges and levels.
0 Falling edges/low levels.
1 Rising edges/high levels.
3
KBF
Keyboard Interrupt Flag — This read-only status flag is set whenever the selected edge event has been
detected on any of the enabled KBI port pins. This flag is cleared by writing a logic 1 to the KBACK control bit.
The flag will remain set if KBIMOD = 1 to select edge-and-level operation and any enabled KBI port pin remains
at the asserted level.
0 No KBI interrupt pending.
1 KBI interrupt pending.
KBF can be used as a software pollable flag (KBIE = 0) or it can generate a hardware interrupt request to the
CPU (KBIE = 1). KBF must be cleared before entering stop mode.
2
KBACK
Keyboard Interrupt Acknowledge — This write-only bit (reads always return 0) is used to clear the KBF status
flag by writing a logic 1 to KBACK. When KBIMOD = 1 to select edge-and-level operation and any enabled KBI
port pin remains at the asserted level, KBF is being continuously set so writing 1 to KBACK does not clear the
KBF flag.
1
KBIE
Keyboard Interrupt Enable — This read/write control bit determines whether hardware interrupts are generated
when the KBF status flag equals 1. When KBIE = 0, no hardware interrupts are generated, but KBF can still be
used for software polling.
0 KBF does not generate hardware interrupts (use polling).
1 KBI hardware interrupt requested when KBF = 1.
0
KBIMOD
Keyboard Detection Mode — This read/write control bit selects either edge-only detection or edge-and-level
detection. KBI port bits 3 through 0 can detect falling edges-only or falling edges and low levels.
KBI port bits 7 through 4 can be configured to detect either:
• Rising edges-only or rising edges and high levels (KBEDGn = 1)
• Falling edges-only or falling edges and low levels (KBEDGn = 0)
0 Edge-only detection.
1 Edge-and-level detection.
Keyboard Interrupt (KBI) Block Description
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
128 Freescale Semiconductor
9.4.2 KBI x Pin Enable Register (KBIxPE)
76543210
R
KBIPE7 KBIPE6 KBIPE5 KBIPE4 KBIPE3 KBIPE2 KBIPE1 KBIPE0
W
Reset 00000000
Figure 9-4. KBI x Pin Enable Register (KBIxPE)
Table 9-2. KBIxPE Field Descriptions
Field Description
7:0
KBIPE[7:0]
Keyboard Pin Enable for KBI Port Bits — Each of these read/write bits selects whether the associated KBI
port pin is enabled as a keyboard interrupt input or functions as a general-purpose I/O pin.
0 Bit n of KBI port is a general-purpose I/O pin not associated with the KBI.
1 Bit n of KBI port enabled as a keyboard interrupt input
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 129
Chapter 10
Timer/PWM Module (S08TPMV1)
10.1 Introduction
The MC9S08RC/RD/RE/RG includes a timer/PWM (TPM) module that supports traditional input capture,
output compare, or buffered edge-aligned pulse-width modulation (PWM) on each channel. A control bit
in the TPM configures both channels in the timer to operate as center-aligned PWM functions. Timing
functions in the TPM are based on a 16-bit counter with prescaler and modulo features to control frequency
and range (period between overflows) of the time reference. This timing system is ideally suited for a wide
range of control applications. The MC9S08RC/RD/RE/RG devices do not have a separate fixed internal
clock source (XCLK). If the XCLK source is selected using the CLKSA and CLKSB control bits (see
Table 10-2), the TPM will use the BUSCLK.
10.2 Features
Timer system features include:
• Two separate channels:
— Each channel may be input capture, output compare, or buffered edge-aligned PWM
— Rising-edge, falling-edge, or any-edge input capture trigger
— Set, clear, or toggle output compare action
— Selectable polarity on PWM outputs
• The TPM may be configured for buffered, center-aligned pulse-width modulation (CPWM) on
both channels
• Clock source to prescaler for the TPM is selectable between the bus clock or an external pin:
— Prescale taps for divide by 1, 2, 4, 8, 16, 32, 64, or 128
— External clock input shared with TPM1CH0 timer channel pin
• 16-bit modulus register to control counter range
• Timer system enable
• One interrupt per channel plus terminal count interrupt
Timer/PWM Module (S08TPMV1)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
130 Freescale Semiconductor
Figure 10-1. MC9S08RC/RD/RE/RG Block Diagram Highlighting TPM Block and Pins
PTD3
PTD4/ACMP1–
PTD5/ACMP1+
PTD6/TPM1CH0
PTC1/KBI2P1
PTC0/KBI2P0
VSS
VDD
PTB3
PTB2
PTA7/KBI1P7–
PTB0/TxD1
PTB1/RxD1
PTD2/IRQ
PTD1/RESET
PTD0/BKGD/MS
PTC7/SS1
PTC6/SPSCK1
PTC5/MISO1
PTC4/MOSI1
PTC3/KBI2P3
PTC2/KBI2P2
PORT A
PORT C
PORT D
PORT B
8-BIT KEYBOARD
INTERRUPT MODULE (KBI1)
SERIAL PERIPHERAL
INTERFACE MODULE (SPI1)
USER FLASH
USER RAM
(RC/RD/RE/RG32/60 = 2048 BYTES)
DEBUG
MODULE (DBG)
(RC/RD/RE/RG60 = 63,364 BYTES)
HCS08 CORE
NOTES
NOTES 1, 5
2-CHANNEL TIMER/PWM
MODULE (TPM1)
PTE7–
PORT E
PTB5
PTB4
PTE6
PTB7/TPM1CH1
MODULE (ACMP1)
HCS08 SYSTEM CONTROL
RESETS AND INTERRUPTS
MODES OF OPERATION
POWER MANAGEMENT
VOLTAGE
REGULATOR
RTI
ANALOG COMPARATOR
COP
IRQ LVD
INTERNAL BUS
LOW-POWER OSCILLATOR
INTERFACE MODULE (SCI1)
SERIAL COMMUNICATIONS
7
PTA1/KBI1P1
8
PTE0
NOTE 1
NOTES1, 2
NOTE 1
(RC/RD/RE/RG32 = 32,768 BYTES)
(RC/RD/RE8/16 = 1024 BYTES)
(RC/RD/RE16 = 16,384 BYTES)
XTAL
EXTAL
CARRIER MODULATOR
TIMER MODULE (CMT)
1, 3, 4
4-BIT KEYBOARD
INTERRUPT MODULE (KBI2)
IRO NOTE 5
PTA0/KBI1P0
(RC/RD/RE8 = 8192 BYTES)
BDC
CPU
NOTES:
13.Port pins are software configurable with pullup device if input port
14.PTA0 does not have a clamp diode to VDD. PTA0 should not be driven above VDD. Also, PTA0 does not pullup to VDD when intern
a
pullup is enabled.
15.IRQ pin contains software configurable pullup/pulldown device if IRQ enabled (IRQPE = 1)
16.The RESET pin contains integrated pullup device enabled if reset enabled (RSTPE = 1)
17.High current drive
18.Pins PTA[7:4] contain both pullup and pulldown devices. Pulldown enabled when KBI is enabled (KBIPEn = 1) and rising edge i
s
selected (KBEDGn = 1).
Timer/PWM (TPM) Block Description
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 131
10.3 TPM Block Diagram
The TPM uses one input/output (I/O) pin per channel, TPM1CHn where n is the channel number (for
example, 0–4). The TPM shares its I/O pins with general-purpose I/O port pins (refer to the Pins and
Connections chapter for more information). Figure 10-2 shows the structure of a TPM. Some MCUs
include more than one TPM, with various numbers of channels.
Figure 10-2. TPM Block Diagram
The central component of the TPM is the 16-bit counter that can operate as a free-running counter, a
modulo counter, or an up-/down-counter when the TPM is configured for center-aligned PWM. The TPM
counter (when operating in normal up-counting mode) provides the timing reference for the input capture,
PRESCALE AND SELECT
16-BIT COMPARATOR
MAIN 16-BIT COUNTER
16-BIT COMPARATOR
16-BIT LATCH
PORT
16-BIT COMPARATOR
16-BIT LATCH
CHANNEL 0
CHANNEL 1
INTERNAL BUS
LOGIC
INTERRUPT
PORT
LOGIC
16-BIT COMPARATOR
16-BIT LATCH
CHANNEL n PORT
LOGIC
COUNTER RESET
DIVIDE BY
CLOCK SOURCE
OFF, BUS, XCLK, EXT
BUSCLK
XCLK
SELECT
SYNC
INTERRUPT
INTERRUPT
INTERRUPT
1, 2, 4, 8, 16, 32, 64, or 128
LOGIC
LOGIC
LOGIC
LOGIC
<st-blue>
<st-blue> <st-blue> <st-blue> <st-blue>
<st-blue>
<st-blue>
<st-blue>
ELS0A
CH0F
ELS0B
ELS1B ELS1A
ELSnB ELSnA
CH1F
CHnF
CH0IE
CH1IE
CHnIE
MS1B
MS0B
MSnB
MS0A
MS1A
MSnA
. . .
. . .
. . .
TPM1MODH:TPM1
TPM1) EXT CLK
TPM1C0VH:TPM1C0VL
TPM1C1VH:TPM1C1VL
TPM1CnVH:TPM1CnVL
TPM1CHn
TPM1CH1
TPM1CH0
Timer/PWM (TPM)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
132 Freescale Semiconductor
output compare, and edge-aligned PWM functions. The timer counter modulo registers,
TPM1MODH:TPM1MODL, control the modulo value of the counter. (The values $0000 or $FFFF
effectively make the counter free running.) Software can read the counter value at any time without
affecting the counting sequence. Any write to either byte of the TPM1CNT counter resets the counter
regardless of the data value written.
All TPM channels are programmable independently as input capture, output compare, or buffered
edge-aligned PWM channels.
10.4 Pin Descriptions
Table 10-2 shows the MCU pins related to the TPM module. When TPM1CH0 is used as an external clock
input, the associated TPM channel 0 can not use the pin. (Channel 0 can still be used in output compare
mode as a software timer.) When any of the pins associated with the timer is configured as a timer input,
a passive pullup can be enabled. After reset, the TPM modules are disabled and all pins default to
general-purpose inputs with the passive pullups disabled.
10.4.1 External TPM Clock Sources
When control bits CLKSB:CLKSA in the timer status and control register are set to 1:1, the prescaler and
consequently the 16-bit counter for TPM1 are driven by an external clock source connected to the
TPM1CH0 pin. A synchronizer is needed between the external clock and the rest of the TPM. This
synchronizer is clocked by the bus clock so the frequency of the external source must be less than one-half
the frequency of the bus rate clock. The upper frequency limit for this external clock source is specified to
be one-fourth the bus frequency to conservatively accommodate duty cycle and phase-locked loop (PLL)
or frequency-locked loop (FLL) frequency jitter effects.
When the TPM is using the channel 0 pin for an external clock, the corresponding ELS0B:ELS0A control
bits should be set to 0:0 so channel 0 is not trying to use the same pin.
10.4.2 TPM1CHn — TPM1 Channel n I/O Pins
Each TPM channel is associated with an I/O pin on the MCU. The function of this pin depends on the
configuration of the channel. In some cases, no pin function is needed so the pin reverts to being controlled
by general-purpose I/O controls. When a timer has control of a port pin, the port data and data direction
registers do not affect the related pin(s). See the Pins and Connections chapter for additional information
about shared pin functions.
10.5 Functional Description
All TPM functions are associated with a main 16-bit counter that allows flexible selection of the clock
source and prescale divisor. A 16-bit modulo register also is associated with the main 16-bit counter in the
TPM. Each TPM channel is optionally associated with an MCU pin and a maskable interrupt function.
The TPM has center-aligned PWM capabilities controlled by the CPWMS control bit in TPM1SC. When
CPWMS is set to 1, timer counter TPM1CNT changes to an up-/down-counter and all channels in the
associated TPM act as center-aligned PWM channels. When CPWMS = 0, each channel can
Timer/PWM (TPM)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 133
independently be configured to operate in input capture, output compare, or buffered edge-aligned PWM
mode.
The following sections describe the main 16-bit counter and each of the timer operating modes (input
capture, output compare, edge-aligned PWM, and center-aligned PWM). Because details of pin operation
and interrupt activity depend on the operating mode, these topics are covered in the associated mode
sections.
10.5.1 Counter
All timer functions are based on the main 16-bit counter (TPM1CNTH:TPM1CNTL). This section
discusses selection of the clock source, up-counting vs. up-/down-counting, end-of-count overflow, and
manual counter reset.
After any MCU reset, CLKSB:CLKSA = 0:0 so no clock source is selected and the TPM is inactive.
Normally, CLKSB:CLKSA would be set to 0:1 so the bus clock drives the timer counter. The clock source
for the TPM can be selected to be off, the bus clock (BUSCLK), the fixed system clock (XCLK), or an
external input through the TPM1CH0 pin. The maximum frequency allowed for the external clock option
is one-fourth the bus rate. Refer to Section 10.7.1, “Timer Status and Control Register (TPM1SC),” and
Table 10-2 for more information about clock source selection.
When the microcontroller is in active background mode, the TPM temporarily suspends all counting until
the microcontroller returns to normal user operating mode. During stop mode, all TPM clocks are stopped;
therefore, the TPM is effectively disabled until clocks resume. During wait mode, the TPM continues to
operate normally.
The main 16-bit counter has two counting modes. When center-aligned PWM is selected (CPWMS = 1),
the counter operates in up-/down-counting mode. Otherwise, the counter operates as a simple up-counter.
As an up-counter, the main 16-bit counter counts from $0000 through its terminal count and then continues
with $0000. The terminal count is $FFFF or a modulus value in TPM1MODH:TPM1MODL.
When center-aligned PWM operation is specified, the counter counts upward from $0000 through its
terminal count and then counts downward to $0000 where it returns to up-counting. Both $0000 and the
terminal count value (value in TPM1MODH:TPM1MODL) are normal length counts (one timer clock
period long).
An interrupt flag and enable are associated with the main 16-bit counter. The timer overflow flag (TOF) is
a software-accessible indication that the timer counter has overflowed. The enable signal selects between
software polling (TOIE = 0) where no hardware interrupt is generated, or interrupt-driven operation
(TOIE = 1) where a static hardware interrupt is automatically generated whenever the TOF flag is 1.
The conditions that cause TOF to become set depend on the counting mode (up or up/down). In
up-counting mode, the main 16-bit counter counts from $0000 through $FFFF and overflows to $0000 on
the next counting clock. TOF becomes set at the transition from $FFFF to $0000. When a modulus limit
is set, TOF becomes set at the transition from the value set in the modulus register to $0000. When the
main 16-bit counter is operating in up-/down-counting mode, the TOF flag gets set as the counter changes
direction at the transition from the value set in the modulus register and the next lower count value. This
corresponds to the end of a PWM period. (The $0000 count value corresponds to the center of a period.)
Timer/PWM (TPM)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
134 Freescale Semiconductor
Because the HCS08 MCU is an 8-bit architecture, a coherency mechanism is built into the timer counter
for read operations. Whenever either byte of the counter is read (TPM1CNTH or TPM1CNTL), both bytes
are captured into a buffer so when the other byte is read, the value will represent the other byte of the count
at the time the first byte was read. The counter continues to count normally, but no new value can be read
from either byte until both bytes of the old count have been read.
The main timer counter can be reset manually at any time by writing any value to either byte of the timer
count TPM1CNTH or TPM1CNTL. Resetting the counter in this manner also resets the coherency
mechanism in case only one byte of the counter was read before resetting the count.
10.5.2 Channel Mode Selection
Provided CPWMS = 0 (center-aligned PWM operation is not specified), the MSnB and MSnA control bits
in the channel n status and control registers determine the basic mode of operation for the corresponding
channel. Choices include input capture, output compare, and buffered edge-aligned PWM.
10.5.2.1 Input Capture Mode
With the input capture function, the TPM can capture the time at which an external event occurs. When an
active edge occurs on the pin of an input capture channel, the TPM latches the contents of the TPM counter
into the channel value registers (TPM1CnVH:TPM1CnVL). Rising edges, falling edges, or any edge may
be chosen as the active edge that triggers an input capture.
When either byte of the 16-bit capture register is read, both bytes are latched into a buffer to support
coherent 16-bit accesses regardless of order. The coherency sequence can be manually reset by writing to
the channel status/control register (TPM1CnSC).
An input capture event sets a flag bit (CHnF) that can optionally generate a CPU interrupt request.
10.5.2.2 Output Compare Mode
With the output compare function, the TPM can generate timed pulses with programmable position,
polarity, duration, and frequency. When the counter reaches the value in the channel value registers of an
output compare channel, the TPM can set, clear, or toggle the channel pin.
In output compare mode, values are transferred to the corresponding timer channel value registers only
after both 8-bit bytes of a 16-bit register have been written. This coherency sequence can be manually reset
by writing to the channel status/control register (TPM1CnSC).
An output compare event sets a flag bit (CHnF) that can optionally generate a CPU interrupt request.
10.5.2.3 Edge-Aligned PWM Mode
This type of PWM output uses the normal up-counting mode of the timer counter (CPWMS = 0) and can
be used when other channels in the same TPM are configured for input capture or output compare
functions. The period of this PWM signal is determined by the setting in the modulus register
(TPM1MODH:TPM1MODL). The duty cycle is determined by the setting in the timer channel value
Timer/PWM (TPM)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 135
register (TPM1CnVH:TPM1CnVL). The polarity of this PWM signal is determined by the setting in the
ELSnA control bit. Duty cycle cases of 0 percent and 100 percent are possible.
As Figure 10-3 shows, the output compare value in the TPM channel registers determines the pulse width
(duty cycle) of the PWM signal. The time between the modulus overflow and the output compare is the
pulse width. If ELSnA = 0, the counter overflow forces the PWM signal high and the output compare
forces the PWM signal low. If ELSnA = 1, the counter overflow forces the PWM signal low and the output
compare forces the PWM signal high.
Figure 10-3. PWM Period and Pulse Width (ELSnA = 0)
When the channel value register is set to $0000, the duty cycle is 0 percent. By setting the timer channel
value register (TPM1CnVH:TPM1CnVL) to a value greater than the modulus setting, 100 percent duty
cycle can be achieved. This implies that the modulus setting must be less than $FFFF to get 100 percent
duty cycle.
Because the HCS08 is a family of 8-bit MCUs, the settings in the timer channel registers are buffered to
ensure coherent 16-bit updates and to avoid unexpected PWM pulse widths. Writes to either register,
TPM1CnVH or TPM1CnVL, write to buffer registers. In edge-PWM mode, values are transferred to the
corresponding timer channel registers only after both 8-bit bytes of a 16-bit register have been written and
the value in the TPM1CNTH:TPM1CNTL counter is $0000. (The new duty cycle does not take effect until
the next full period.)
10.5.3 Center-Aligned PWM Mode
This type of PWM output uses the up-/down-counting mode of the timer counter (CPWMS = 1). The
output compare value in TPM1CnVH:TPM1CnVL determines the pulse width (duty cycle) of the PWM
signal and the period is determined by the value in TPM1MODH:TPM1MODL.
TPM1MODH:TPM1MODL should be kept in the range of $0001 to $7FFF because values outside this
range can produce ambiguous results. ELSnA will determine the polarity of the CPWM output.
pulse width = 2 x (TPM1CnVH:TPM1CnVL) Eqn. 10-1
period = 2 x (TPM1MODH:TPM1MODL);
for TPM1MODH:TPM1MODL = $0001–$7FFF Eqn. 10-2
If the channel value register TPM1CnVH:TPM1CnVL is zero or negative (bit 15 set), the duty cycle will
be 0 percent. If TPM1CnVH:TPM1CnVL is a positive value (bit 15 clear) and is greater than the (nonzero)
modulus setting, the duty cycle will be 100 percent because the duty cycle compare will never occur. This
implies the usable range of periods set by the modulus register is $0001 through $7FFE ($7FFF if
PERIOD
PULSE
WIDTH
OVERFLOW OVERFLOW OVERFLOW
OUTPUT
COMPARE
OUTPUT
COMPARE
OUTPUT
COMPARE
TPM1C
Timer/PWM (TPM)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
136 Freescale Semiconductor
generation of 100 percent duty cycle is not necessary). This is not a significant limitation because the
resulting period is much longer than required for normal applications.
TPM1MODH:TPM1MODL = $0000 is a special case that should not be used with center-aligned PWM
mode. When CPWMS = 0, this case corresponds to the counter running free from $0000 through $FFFF,
but when CPWMS = 1 the counter needs a valid match to the modulus register somewhere other than at
$0000 in order to change directions from up-counting to down-counting.
Figure 10-4 shows the output compare value in the TPM channel registers (multiplied by 2), which
determines the pulse width (duty cycle) of the CPWM signal. If ELSnA = 0, the compare match while
counting up forces the CPWM output signal low and a compare match while counting down forces the
output high. The counter counts up until it reaches the modulo setting in TPM1MODH:TPM1MODL, then
counts down until it reaches zero. This sets the period equal to two times TPM1MODH:TPM1MODL.
Figure 10-4. CPWM Period and Pulse Width (ELSnA = 0)
Center-aligned PWM outputs typically produce less noise than edge-aligned PWMs because fewer I/O pin
transitions are lined up at the same system clock edge. This type of PWM is also required for some types
of motor drives.
Because the HCS08 is a family of 8-bit MCUs, the settings in the timer channel registers are buffered to
ensure coherent 16-bit updates and to avoid unexpected PWM pulse widths. Writes to any of the registers,
TPM1MODH, TPM1MODL, TPM1CnVH, and TPM1CnVL, actually write to buffer registers. Values are
transferred to the corresponding timer channel registers only after both 8-bit bytes of a 16-bit register have
been written and the timer counter overflows (reverses direction from up-counting to down-counting at the
end of the terminal count in the modulus register). This TPM1CNT overflow requirement only applies to
PWM channels, not output compares.
Optionally, when TPM1CNTH:TPM1CNTL = TPM1MODH:TPM1MODL, the TPM can generate a TOF
interrupt at the end of this count. The user can choose to reload any number of the PWM buffers, and they
will all update simultaneously at the start of a new period.
Writing to TPM1SC cancels any values written to TPM1MODH and/or TPM1MODL and resets the
coherency mechanism for the modulo registers. Writing to TPM1CnSC cancels any values written to the
channel value registers and resets the coherency mechanism for TPM1CnVH:TPM1CnVL.
PERIOD
PULSE WIDTH
COUNT =
COUNT = 0
OUTPUT
COMPARE
(COUNT UP)
OUTPUT
COMPARE
(COUNT DOWN)
COUNT =
TPM1MODH:TPM
TPM1C
TPM1MODH:TPM
2 x
2 x
Timer/PWM (TPM)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 137
10.6 TPM Interrupts
The TPM generates an optional interrupt for the main counter overflow and an interrupt for each channel.
The meaning of channel interrupts depends on the mode of operation for each channel. If the channel is
configured for input capture, the interrupt flag is set each time the selected input capture edge is
recognized. If the channel is configured for output compare or PWM modes, the interrupt flag is set each
time the main timer counter matches the value in the 16-bit channel value register. See the Resets,
Interrupts, and System Configuration chapter for absolute interrupt vector addresses, priority, and local
interrupt mask control bits.
For each interrupt source in the TPM, a flag bit is set on recognition of the interrupt condition such as timer
overflow, channel input capture, or output compare events. This flag may be read (polled) by software to
verify that the action has occurred, or an associated enable bit (TOIE or CHnIE) can be set to enable
hardware interrupt generation. While the interrupt enable bit is set, a static interrupt will be generated
whenever the associated interrupt flag equals 1. It is the responsibility of user software to perform a
sequence of steps to clear the interrupt flag before returning from the interrupt service routine.
10.6.1 Clearing Timer Interrupt Flags
TPM interrupt flags are cleared by a 2-step process that includes a read of the flag bit while it is set (1)
followed by a write of 0 to the bit. If a new event is detected between these two steps, the sequence is reset
and the interrupt flag remains set after the second step to avoid the possibility of missing the new event.
10.6.2 Timer Overflow Interrupt Description
The conditions that cause TOF to become set depend on the counting mode (up or up/down). In
up-counting mode, the 16-bit timer counter counts from $0000 through $FFFF and overflows to $0000 on
the next counting clock. TOF becomes set at the transition from $FFFF to $0000. When a modulus limit
is set, TOF becomes set at the transition from the value set in the modulus register to $0000. When the
counter is operating in up-/down-counting mode, the TOF flag gets set as the counter changes direction at
the transition from the value set in the modulus register and the next lower count value. This corresponds
to the end of a PWM period. (The $0000 count value corresponds to the center of a period.)
10.6.3 Channel Event Interrupt Description
The meaning of channel interrupts depends on the current mode of the channel (input capture, output
compare, edge-aligned PWM, or center-aligned PWM).
When a channel is configured as an input capture channel, the ELSnB:ELSnA control bits select rising
edges, falling edges, any edge, or no edge (off) as the edge that triggers an input capture event. When the
selected edge is detected, the interrupt flag is set. The flag is cleared by the 2-step sequence described in
Section 10.6.1, “Clearing Timer Interrupt Flags.”
When a channel is configured as an output compare channel, the interrupt flag is set each time the main
timer counter matches the 16-bit value in the channel value register. The flag is cleared by the 2-step
sequence described in Section 10.6.1, “Clearing Timer Interrupt Flags.”
Timer/PWM (TPM)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
138 Freescale Semiconductor
10.6.4 PWM End-of-Duty-Cycle Events
For channels that are configured for PWM operation, there are two possibilities:
• When the channel is configured for edge-aligned PWM, the channel flag is set when the timer
counter matches the channel value register that marks the end of the active duty cycle period.
• When the channel is configured for center-aligned PWM, the timer count matches the channel
value register twice during each PWM cycle. In this CPWM case, the channel flag is set at the start
and at the end of the active duty cycle, which are the times when the timer counter matches the
channel value register.
The flag is cleared by the 2-step sequence described in Section 10.6.1, “Clearing Timer Interrupt Flags.”
10.7 TPM Registers and Control Bits
The TPM includes:
• An 8-bit status and control register (TPM1SC)
• A 16-bit counter (TPM1CNTH:TPM1CNTL)
• A 16-bit modulo register (TPM1MODH:TPM1MODL)
Each timer channel has:
• An 8-bit status and control register (TPM1CnSC)
• A 16-bit channel value register (TPM1CnVH:TPM1CnVL)
Refer to the direct-page register summary in the Memory chapter of this data sheet for the absolute address
assignments for all TPM registers. This section refers to registers and control bits only by their names. A
Freescale-provided equate or header file is used to translate these names into the appropriate absolute
addresses.
Timer/PWM (TPM)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 139
10.7.1 Timer Status and Control Register (TPM1SC)
TPM1SC contains the overflow status flag and control bits that are used to configure the interrupt enable,
TPM configuration, clock source, and prescale divisor. These controls relate to all channels within this
timer module.
76543210
RTOF
TOIE CPWMS CLKSB CLKSA PS2 PS1 PS0
W
Reset 00000000
= Unimplemented or Reserved
Figure 10-5. Timer Status and Control Register (TPM1SC)
Table 10-1. TPM1SC Register Field Descriptions
Field Description
7
TOF
Timer Overflow Flag — This flag is set when the TPM counter changes to $0000 after reaching the modulo
value programmed in the TPM counter modulo registers. When the TPM is configured for CPWM, TOF is set
after the counter has reached the value in the modulo register, at the transition to the next lower count value.
Clear TOF by reading the TPM status and control register when TOF is set and then writing a 0 to TOF. If another
TPM overflow occurs before the clearing sequence is complete, the sequence is reset so TOF would remain set
after the clear sequence was completed for the earlier TOF. Reset clears TOF. Writing a 1 to TOF has no effect.
0 TPM counter has not reached modulo value or overflow
1 TPM counter has overflowed
6
TOIE
Timer Overflow Interrupt Enable — This read/write bit enables TPM overflow interrupts. If TOIE is set, an
interrupt is generated when TOF equals 1. Reset clears TOIE.
0 TOF interrupts inhibited (use software polling)
1 TOF interrupts enabled
5
CPWMS
Center-Aligned PWM Select — This read/write bit selects CPWM operating mode. Reset clears this bit so the
TPM operates in up-counting mode for input capture, output compare, and edge-aligned PWM functions. Setting
CPWMS reconfigures the TPM to operate in up-/down-counting mode for CPWM functions. Reset clears
CPWMS.
0 All TPM1 channels operate as input capture, output compare, or edge-aligned PWM mode as selected by the
MSnB:MSnA control bits in each channel’s status and control register
1 All TPM1 channels operate in center-aligned PWM mode
4:3
CLKS[B:A]
Clock Source Select — As shown in Table 10-2, this 2-bit field is used to disable the TPM system or select one
of three clock sources to drive the counter prescaler. The external source and the XCLK are synchronized to the
bus clock by an on-chip synchronization circuit.
2:0
PS[2:0]
Prescale Divisor Select — This 3-bit field selects one of eight divisors for the TPM clock input as shown in
Table 10-3. This prescaler is located after any clock source synchronization or clock source selection, so it affects
whatever clock source is selected to drive the TPM system.
Timer/PWM (TPM)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
140 Freescale Semiconductor
10.7.2 Timer Counter Registers (TPM1CNTH:TPM1CNTL)
The two read-only TPM counter registers contain the high and low bytes of the value in the TPM counter.
Reading either byte (TPM1CNTH or TPM1CNTL) latches the contents of both bytes into a buffer where
they remain latched until the other byte is read. This allows coherent 16-bit reads in either order. The
coherency mechanism is automatically restarted by an MCU reset, a write of any value to TPM1CNTH or
TPM1CNTL, or any write to the timer status/control register (TPM1SC).
Reset clears the TPM counter registers.
Table 10-2. TPM Clock Source Selection
CLKSB:CLKSA TPM Clock Source to Prescaler Input
0:0 No clock selected (TPM disabled)
0:1 Bus rate clock (BUSCLK)
1:0 Fixed system clock (XCLK)
1:1 External source (TPM1 Ext Clk)1,2
1. The maximum frequency that is allowed as an external clock is one-fourth of the bus frequency.
2. When the TPM1CH0 pin is selected as the TPM clock source, the corresponding ELS0B:ELS0A control bits should be set to
0:0 so channel 0 does not try to use the same pin for a conflicting function.
Table 10-3. Prescale Divisor Selection
PS2:PS1:PS0 TPM Clock Source Divided-By
0:0:0 1
0:0:1 2
0:1:0 4
0:1:1 8
1:0:0 16
1:0:1 32
1:1:0 64
1:1:1 128
76543210
R Bit 15 14 13 12 11 10 9 Bit 8
W Any write to TPM1CNTH clears the 16-bit counter.
Reset 00000000
Figure 10-6. Timer Counter Register High (TPM1CNTH)
76543210
R Bit 7 654321Bit 0
W Any write to TPM1CNTL clears the 16-bit counter.
Reset 00000000
Figure 10-7. Timer Counter Register Low (TPM1CNTL)
Timer/PWM (TPM)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 141
When background mode is active, the timer counter and the coherency mechanism are frozen such that the
buffer latches remain in the state they were in when the background mode became active even if one or
both bytes of the counter are read while background mode is active.
10.7.3 Timer Counter Modulo Registers (TPM1MODH:TPM1MODL)
The read/write TPM modulo registers contain the modulo value for the TPM counter. After the TPM
counter reaches the modulo value, the TPM counter resumes counting from $0000 at the next clock
(CPWMS = 0) or starts counting down (CPWMS = 1), and the overflow flag (TOF) becomes set. Writing
to TPM1MODH or TPM1MODL inhibits the TOF bit and overflow interrupts until the other byte is
written. Reset sets the TPM counter modulo registers to $0000, which results in a free-running timer
counter (modulo disabled).
It is good practice to wait for an overflow interrupt so both bytes of the modulo register can be written well
before a new overflow. An alternative approach is to reset the TPM counter before writing to the TPM
modulo registers to avoid confusion about when the first counter overflow will occur.
76543210
R
Bit 15 14 13 12 11 10 9 Bit 8
W
Reset 00000000
Figure 10-8. Timer Counter Modulo Register High (TPM1MODH)
76543210
R
Bit 7 654321Bit 0
W
Reset 00000000
Figure 10-9. Timer Counter Modulo Register Low (TPM1MODL)
Timer/PWM (TPM)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
142 Freescale Semiconductor
10.7.4 Timer Channel n Status and Control Register (TPM1CnSC)
TPM1CnSC contains the channel interrupt status flag and control bits that are used to configure the
interrupt enable, channel configuration, and pin function.
76543210
R
CHnF CHnIE MSnB MSnA ELSnB ELSnA
00
W
Reset 00000000
= Unimplemented or Reserved
Figure 10-10. Timer Channel n Status and Control Register (TPM1CnSC)
Table 10-4. TPM1CnSC Register Field Descriptions
Field Description
7
CHnF
Channel n Flag — When channel n is configured for input capture, this flag bit is set when an active edge occurs
on the channel n pin. When channel n is an output compare or edge-aligned PWM channel, CHnF is set when
the value in the TPM counter registers matches the value in the TPM channel n value registers. This flag is
seldom used with center-aligned PWMs because it is set every time the counter matches the channel value
register, which correspond to both edges of the active duty cycle period.
A corresponding interrupt is requested when CHnF is set and interrupts are enabled (CHnIE = 1). Clear CHnF
by reading TPM1CnSC while CHnF is set and then writing a 0 to CHnF. If another interrupt request occurs before
the clearing sequence is complete, the sequence is reset so CHnF would remain set after the clear sequence
was completed for the earlier CHnF. This is done so a CHnF interrupt request cannot be lost by clearing a
previous CHnF. Reset clears CHnF. Writing a 1 to CHnF has no effect.
0 No input capture or output compare event occurred on channel n
1 Input capture or output compare event occurred on channel n
6
CHnIE
Channel n Interrupt Enable — This read/write bit enables interrupts from channel n. Reset clears CHnIE.
0 Channel n interrupt requests disabled (use software polling)
1 Channel n interrupt requests enabled
5
MSnB
Mode Select B for TPM Channel n — When CPWMS = 0, MSnB = 1 configures TPM channel n for
edge-aligned PWM mode. For a summary of channel mode and setup controls, refer to Table 10-5.
4
MSnA
Mode Select A for TPM Channel n — When CPWMS = 0 and MSnB = 0, MSnA configures TPM channel n for
input capture mode or output compare mode. Refer to Table 10-5 for a summary of channel mode and setup
controls.
3:2
ELSn[B:A]
Edge/Level Select Bits — Depending on the operating mode for the timer channel as set by
CPWMS:MSnB:MSnA and shown in Table 10-5, these bits select the polarity of the input edge that triggers an
input capture event, select the level that will be driven in response to an output compare match, or select the
polarity of the PWM output.
Setting ELSnB:ELSnA to 0:0 configures the related timer pin as a general-purpose I/O pin unrelated to any timer
channel functions. This function is typically used to temporarily disable an input capture channel or to make the
timer pin available as a general-purpose I/O pin when the associated timer channel is set up as a software timer
that does not require the use of a pin. This is also the setting required for channel 0 when the TPM1CH0 pin is
used as an external clock input.
Timer/PWM (TPM)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 143
If the associated port pin is not stable for at least two bus clock cycles before changing to input capture
mode, it is possible to get an unexpected indication of an edge trigger. Typically, a program would clear
status flags after changing channel configuration bits and before enabling channel interrupts or using the
status flags to avoid any unexpected behavior.
10.7.5 Timer Channel Value Registers (TPM1CnVH:TPM1CnVL)
These read/write registers contain the captured TPM counter value of the input capture function or the
output compare value for the output compare or PWM functions. The channel value registers are cleared
by reset.
Table 10-5. Mode, Edge, and Level Selection
CPWMS MSnB:MSnA ELSnB:ELSnA Mode Configuration
XXX 00
Pin not used for TPM channel; use as an external clock for the TPM or
revert to general-purpose I/O
0
00
01
Input capture
Capture on rising edge only
10 Capture on falling edge only
11 Capture on rising or falling edge
01
00
Output compare
Software compare only
01 Toggle output on compare
10 Clear output on compare
11 Set output on compare
1X 10 Edge-aligned
PWM
High-true pulses (clear output on compare)
X1 Low-true pulses (set output on compare)
1XX 10 Center-aligned
PWM
High-true pulses (clear output on compare-up)
X1 Low-true pulses (set output on compare-up)
76543210
R
Bit 15 14 13 12 11 10 9 Bit 8
W
Reset 00000000
Figure 10-11. Timer Channel Value Register High (TPM1CnVH)
76543210
R
Bit 7 654321Bit 0
W
Reset 00000000
Figure 10-12. Timer Channel Value Register Low (TPM1CnVL)
Timer/PWM (TPM)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
144 Freescale Semiconductor
In input capture mode, reading either byte (TPM1CnVH or TPM1CnVL) latches the contents of both bytes
into a buffer where they remain latched until the other byte is read. This latching mechanism also resets
(becomes unlatched) when the TPM1CnSC register is written.
In output compare or PWM modes, writing to either byte (TPM1CnVH or TPM1CnVL) latches the value
into a buffer. When both bytes have been written, they are transferred as a coherent 16-bit value into the
timer channel value registers. This latching mechanism may be manually reset by writing to the
TPM1CnSC register.
This latching mechanism allows coherent 16-bit writes in either order, which is friendly to various
compiler implementations.
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 145
Chapter 11
Serial Communications Interface (S08SCIV1)
11.1 Introduction
The MC9S08RDxx, MC9S08RExx, and MC9S08RGxx devices include a serial communications interface
(SCI) module, which is sometimes called a universal asynchronous receiver/transmitters (UART). The SCI
module shares pins with PTB0 and PTB1 port pins. When the SCI is enabled, the pins are controlled by
the SCI module.
Figure 11-1 is a device-level block diagram with the SCI highlighted.
Serial Communications Interface (S08SCIV1)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
146 Freescale Semiconductor
Figure 11-1. MC9S08RC/RD/RE/RG Block Diagram Highlighting SCI Block and Pins
PTD3
PTD4/ACMP1–
PTD5/ACMP1+
PTD6/TPM1CH0
PTC1/KBI2P1
PTC0/KBI2P0
VSS
VDD
PTB3
PTB2
PTA7/KBI1P7–
PTB0/TxD1
PTB1/RxD1
PTD2/IRQ
PTD1/RESET
PTD0/BKGD/MS
PTC7/SS1
PTC6/SPSCK1
PTC5/MISO1
PTC4/MOSI1
PTC3/KBI2P3
PTC2/KBI2P2
PORT A
PORT C
PORT D
PORT B
8-BIT KEYBOARD
INTERRUPT MODULE (KBI1)
SERIAL PERIPHERAL
INTERFACE MODULE (SPI1)
USER FLASH
USER RAM
(RC/RD/RE/RG32/60 = 2048 BYTES)
DEBUG
MODULE (DBG)
(RC/RD/RE/RG60 = 63,364 BYTES)
HCS08 CORE
NOTES
NOTES 1, 5
2-CHANNEL TIMER/PWM
MODULE (TPM1)
PTE7–
PORT E
PTB5
PTB4
PTE6
PTB7/TPM1CH1
MODULE (ACMP1)
HCS08 SYSTEM CONTROL
RESETS AND INTERRUPTS
MODES OF OPERATION
POWER MANAGEMENT
VOLTAGE
REGULATOR
RTI
ANALOG COMPARATOR
COP
IRQ LVD
INTERNAL BUS
LOW-POWER OSCILLATOR
INTERFACE MODULE (SCI1)
SERIAL COMMUNICATIONS
7
PTA1/KBI1P1
8
PTE0
NOTE 1
NOTES1, 2
NOTE 1
(RC/RD/RE/RG32 = 32,768 BYTES)
(RC/RD/RE8/16 = 1024 BYTES)
(RC/RD/RE16 = 16,384 BYTES)
XTAL
EXTAL
CARRIER MODULATOR
TIMER MODULE (CMT)
1, 3, 4
4-BIT KEYBOARD
INTERRUPT MODULE (KBI2)
IRO NOTE 5
PTA0/KBI1P0
(RC/RD/RE8 = 8192 BYTES)
BDC
CPU
NOTES:
1. Port pins are software configurable with pullup device if input port
2. PTA0 does not have a clamp diode to VDD. PTA0 should not be driven above VDD. Also, PTA0 does not pullup to VDD when internal
pullup is enabled.
3. IRQ pin contains software configurable pullup/pulldown device if IRQ enabled (IRQPE = 1)
4. The RESET pin contains integrated pullup device enabled if reset enabled (RSTPE = 1)
5. High current drive
6. Pins PTA[7:4] contain both pullup and pulldown devices. Pulldown enabled when KBI is enabled (KBIPEn = 1) and rising edge is
selected (KBEDGn = 1).
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 147
Chapter 12
Serial Communications Interface (S08SCIV1)
12.1 Introduction
12.1.1 Features
Features of SCI module include:
• Full-duplex, standard non-return-to-zero (NRZ) format
• Double-buffered transmitter and receiver with separate enables
• Programmable baud rates (13-bit modulo divider)
• Interrupt-driven or polled operation:
— Transmit data register empty and transmission complete
— Receive data register full
— Receive overrun, parity error, framing error, and noise error
— Idle receiver detect
• Hardware parity generation and checking
• Programmable 8-bit or 9-bit character length
• Receiver wakeup by idle-line or address-mark
12.1.2 Modes of Operation
See Section 12.3, “Functional Description,” for a detailed description of SCI operation in the different
modes.
• 8- and 9- bit data modes
• Stop modes — SCI is halted during all stop modes
• Loop modes
Serial Communications Interface (S08SCIV1)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
148 Freescale Semiconductor
12.1.3 Block Diagram
Figure 12-1 shows the transmitter portion of the SCI. (Figure 12-2 shows the receiver portion of the SCI.)
Figure 12-1. SCI Transmitter Block Diagram
H876543210L
SCID – Tx BUFFER
(WRITE-ONLY)
INTERNAL BUS
STOP
11-BIT TRANSMIT SHIFT REGISTER
START
SHIFT DIRECTION
LSB
1× BAUD
RATE CLOCK
PARITY
GENERATION
TRANSMIT CONTROL
SHIFT ENABLE
PREAMBLE (ALL 1s)
BREAK (ALL 0s)
SCI CONTROLS TxD
TxD DIRECTION
TO TxD
PIN LOGIC
LOOP
CONTROL
TO RECEIVE
DATA IN
TO TxD PIN
Tx INTERRUPT
REQUEST
LOOPS
RSRC
TIE
TC
TDRE
M
PT
PE
TCIE
TE
SBK
T8
TXDIR
LOAD FROM SCI1D
ENABLE
Serial Communications Interface (S08SCIV1)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 149
Figure 12-2 shows the receiver portion of the SCI.
Figure 12-2. SCI Receiver Block Diagram
H876543210L
SCID – Rx BUFFER
(READ-ONLY)
INTERNAL BUS
STOP
11-BIT RECEIVE SHIFT REGISTER
START
SHIFT DIRECTION
LSB
FROM RxD PIN
RATE CLOCK
Rx INTERRUPT
REQUEST
DATA RECOVERY
DIVIDE
16 × BAUD
SINGLE-WIRE
LOOP CONTROL
WAKEUP
LOGIC
ALL 1s
MSB
FROM
TRANSMITTER
ERROR INTERRUPT
REQUEST
PARITY
CHECKING
BY 16
RDRF
RIE
IDLE
ILIE
OR
ORIE
FE
FEIE
NF
NEIE
PF
LOOPS
PEIE
PT
PE
RSRC
WAKE
ILT
RWU
M
Serial Communications Interface (S08SCIV1)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
150 Freescale Semiconductor
12.2 Register Definition
The SCI has eight 8-bit registers to control baud rate, select SCI options, report SCI status, and for
transmit/receive data.
Refer to the direct-page register summary in the Memory chapter of this data sheet for the absolute address
assignments for all SCI registers. This section refers to registers and control bits only by their names. A
Freescale-provided equate or header file is used to translate these names into the appropriate absolute
addresses.
12.2.1 SCI Baud Rate Registers (SCI1BDH, SCI1BHL)
This pair of registers controls the prescale divisor for SCI baud rate generation. To update the 13-bit baud
rate setting [SBR12:SBR0], first write to SCI1BDH to buffer the high half of the new value and then write
to SCI1BDL. The working value in SCI1BDH does not change until SCI1BDL is written.
SCI1BDL is reset to a non-zero value, so after reset the baud rate generator remains disabled until the first
time the receiver or transmitter is enabled (RE or TE bits in SCI1C2 are written to 1).
76543210
R000
SBR12 SBR11 SBR10 SBR9 SBR8
W
Reset 00000000
= Unimplemented or Reserved
Figure 12-3. SCI Baud Rate Register (SCI1BDH)
Table 12-1. SCI1BDH Register Field Descriptions
Field Description
4:0
SBR[12:8]
Baud Rate Modulo Divisor — These 13 bits are referred to collectively as BR, and they set the modulo divide
rate for the SCI baud rate generator. When BR = 0, the SCI baud rate generator is disabled to reduce supply
current. When BR = 1 to 8191, the SCI baud rate = BUSCLK/(16×BR). See also BR bits in Table 12-2.
76543210
R
SBR7 SBR6 SBR5 SBR4 SBR3 SBR2 SBR1 SBR0
W
Reset 00000100
Figure 12-4. SCI Baud Rate Register (SCI1BDL)
Table 12-2. SCI1BDL Register Field Descriptions
Field Description
7:0
SBR[7:0]
Baud Rate Modulo Divisor — These 13 bits are referred to collectively as BR, and they set the modulo divide
rate for the SCI baud rate generator. When BR = 0, the SCI baud rate generator is disabled to reduce supply
current. When BR = 1 to 8191, the SCI baud rate = BUSCLK/(16×BR). See also BR bits in Table 12-1.
Serial Communications Interface (S08SCIV1)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 151
12.2.2 SCI Control Register 1 (SCI1C1)
This read/write register is used to control various optional features of the SCI system.
76543210
R
LOOPS SCISWAI RSRC M WAKE ILT PE PT
W
Reset 00000000
Figure 12-5. SCI Control Register 1 (SCI1C1)
Table 12-3. SCI1C1 Register Field Descriptions
Field Description
7
LOOPS
Loop Mode Select — Selects between loop back modes and normal 2-pin full-duplex modes. When
LOOPS = 1, the transmitter output is internally connected to the receiver input.
0 Normal operation — RxD and TxD use separate pins.
1 Loop mode or single-wire mode where transmitter outputs are internally connected to receiver input. (See
RSRC bit.) RxD pin is not used by SCI.
6
SCISWAI
SCI Stops in Wait Mode
0 SCI clocks continue to run in wait mode so the SCI can be the source of an interrupt that wakes up the CPU.
1 SCI clocks freeze while CPU is in wait mode.
5
RSRC
Receiver Source Select — This bit has no meaning or effect unless the LOOPS bit is set to 1. When
LOOPS = 1, the receiver input is internally connected to the TxD pin and RSRC determines whether this
connection is also connected to the transmitter output.
0 Provided LOOPS = 1, RSRC = 0 selects internal loop back mode and the SCI does not use the RxD pins.
1 Single-wire SCI mode where the TxD pin is connected to the transmitter output and receiver input.
4
M
9-Bit or 8-Bit Mode Select
0 Normal — start + 8 data bits (LSB first) + stop.
1 Receiver and transmitter use 9-bit data characters
start + 8 data bits (LSB first) + 9th data bit + stop.
3
WAKE
Receiver Wakeup Method Select — Refer to Section 12.3.3.2, “Receiver Wakeup Operation” for more
information.
0 Idle-line wakeup.
1 Address-mark wakeup.
2
ILT
Idle Line Type Select — Setting this bit to 1 ensures that the stop bit and logic 1 bits at the end of a character
do not count toward the 10 or 11 bit times of the logic high level by the idle line detection logic. Refer to
Section 12.3.3.2.1, “Idle-Line Wakeup” for more information.
0 Idle character bit count starts after start bit.
1 Idle character bit count starts after stop bit.
1
PE
Parity Enable — Enables hardware parity generation and checking. When parity is enabled, the most significant
bit (MSB) of the data character (eighth or ninth data bit) is treated as the parity bit.
0 No hardware parity generation or checking.
1 Parity enabled.
0
PT
Parity Type — Provided parity is enabled (PE = 1), this bit selects even or odd parity. Odd parity means the total
number of 1s in the data character, including the parity bit, is odd. Even parity means the total number of 1s in
the data character, including the parity bit, is even.
0 Even parity.
1 Odd parity.
Serial Communications Interface (S08SCIV1)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
152 Freescale Semiconductor
12.2.3 SCI Control Register 2 (SCI1C2)
This register can be read or written at any time.
76543210
R
TIE TCIE RIE ILIE TE RE RWU SBK
W
Reset 00000000
Figure 12-6. SCI Control Register 2 (SCI1C2)
Table 12-4. SCI1C2 Register Field Descriptions
Field Description
7
TIE
Transmit Interrupt Enable (for TDRE)
0 Hardware interrupts from TDRE disabled (use polling).
1 Hardware interrupt requested when TDRE flag is 1.
6
TCIE
Transmission Complete Interrupt Enable (for TC)
0 Hardware interrupt requested when TC flag is 1.
1 Hardware interrupts from TC disabled (use polling).
5
RIE
Receiver Interrupt Enable (for RDRF)
0 Hardware interrupts from RDRF disabled (use polling).
1 Hardware interrupt requested when RDRF flag is 1.
4
ILIE
Idle Line Interrupt Enable (for IDLE)
0 Hardware interrupts from IDLE disabled (use polling).
1 Hardware interrupt requested when IDLE flag is 1.
3
TE
Transmitter Enable
0 Transmitter off.
1 Transmitter on.
TE must be 1 in order to use the SCI transmitter. Normally, when TE = 1, the SCI forces the TxD pin to act as an
output for the SCI system. If LOOPS = 1 and RSRC = 0, the TxD pin reverts to being a port B general-purpose
I/O pin even if TE = 1.
When the SCI is configured for single-wire operation (LOOPS = RSRC = 1), TXDIR controls the direction of
traffic on the single SCI communication line (TxD pin).
TE also can be used to queue an idle character by writing TE = 0 then TE = 1 while a transmission is in progress.
Refer to Section 12.3.2.1, “Send Break and Queued Idle,” for more details.
When TE is written to 0, the transmitter keeps control of the port TxD pin until any data, queued idle, or queued
break character finishes transmitting before allowing the pin to revert to a general-purpose I/O pin.
2
RE
Receiver Enable — When the SCI receiver is off, the RxD pin reverts to being a general-purpose port I/O pin.
0 Receiver off.
1 Receiver on.
Serial Communications Interface (S08SCIV1)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 153
12.2.4 SCI Status Register 1 (SCI1S1)
This register has eight read-only status flags. Writes have no effect. Special software sequences (which do
not involve writing to this register) are used to clear these status flags.
1
RWU
Receiver Wakeup Control — This bit can be written to 1 to place the SCI receiver in a standby state where it
waits for automatic hardware detection of a selected wakeup condition. The wakeup condition is either an idle
line between messages (WAKE = 0, idle-line wakeup), or a logic 1 in the most significant data bit in a character
(WAKE = 1, address-mark wakeup). Application software sets RWU and (normally) a selected hardware
condition automatically clears RWU. Refer to Section 12.3.3.2, “Receiver Wakeup Operation,” for more details.
0 Normal SCI receiver operation.
1 SCI receiver in standby waiting for wakeup condition.
0
SBK
Send Break — Writing a 1 and then a 0 to SBK queues a break character in the transmit data stream. Additional
break characters of 10 or 11 bit times of logic 0 are queued as long as SBK = 1. Depending on the timing of the
set and clear of SBK relative to the information currently being transmitted, a second break character may be
queued before software clears SBK. Refer to Section 12.3.2.1, “Send Break and Queued Idle,” for more details.
0 Normal transmitter operation.
1 Queue break character(s) to be sent.
76543210
RTDRE TC RDRF IDLE OR NF FE PF
W
Reset 11000000
= Unimplemented or Reserved
Figure 12-7. SCI Status Register 1 (SCI1S1)
Table 12-5. SCI1S1 Register Field Descriptions
Field Description
7
TDRE
Transmit Data Register Empty Flag — TDRE is set immediately after reset and when a transmit data value
transfers from the transmit data buffer to the transmit shifter, leaving room for a new character in the buffer. To
clear TDRE, read SCI1S1 with TDRE = 1 and then write to the SCI data register (SCI1D).
0 Transmit data register (buffer) full.
1 Transmit data register (buffer) empty.
6
TC
Transmission Complete Flag — TC is set immediately after reset and when TDRE = 1 and no data, preamble,
or break character is being transmitted.
0 Transmitter active (sending data, a preamble, or a break).
1 Transmitter idle (transmission activity complete).
TC is cleared automatically by reading SCI1S1 with TC = 1 and then doing one of the following three things:
• Write to the SCI data register (SCI1D) to transmit new data
• Queue a preamble by changing TE from 0 to 1
• Queue a break character by writing 1 to SBK in SCI1C2
Table 12-4. SCI1C2 Register Field Descriptions (continued)
Field Description
Serial Communications Interface (S08SCIV1)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
154 Freescale Semiconductor
5
RDRF
Receive Data Register Full Flag — RDRF becomes set when a character transfers from the receive shifter into
the receive data register (SCI1D). To clear RDRF, read SCI1S1 with RDRF = 1 and then read the SCI data
register (SCI1D).
0 Receive data register empty.
1 Receive data register full.
4
IDLE
Idle Line Flag — IDLE is set when the SCI receive line becomes idle for a full character time after a period of
activity. When ILT = 0, the receiver starts counting idle bit times after the start bit. So if the receive character is
all 1s, these bit times and the stop bit time count toward the full character time of logic high (10 or 11 bit times
depending on the M control bit) needed for the receiver to detect an idle line. When ILT = 1, the receiver doesn’t
start counting idle bit times until after the stop bit. So the stop bit and any logic high bit times at the end of the
previous character do not count toward the full character time of logic high needed for the receiver to detect an
idle line.
To clear IDLE, read SCI1S1 with IDLE = 1 and then read the SCI data register (SCI1D). After IDLE has been
cleared, it cannot become set again until after a new character has been received and RDRF has been set. IDLE
will get set only once even if the receive line remains idle for an extended period.
0 No idle line detected.
1 Idle line was detected.
3
OR
Receiver Overrun Flag — OR is set when a new serial character is ready to be transferred to the receive data
register (buffer), but the previously received character has not been read from SCI1D yet. In this case, the new
character (and all associated error information) is lost because there is no room to move it into SCI1D. To clear
OR, read SCI1S1 with OR = 1 and then read the SCI data register (SCI1D).
0 No overrun.
1 Receive overrun (new SCI data lost).
2
NF
Noise Flag — The advanced sampling technique used in the receiver takes seven samples during the start bit
and three samples in each data bit and the stop bit. If any of these samples disagrees with the rest of the samples
within any bit time in the frame, the flag NF will be set at the same time as the flag RDRF gets set for the
character. To clear NF, read SCI1S1 and then read the SCI data register (SCI1D).
0 No noise detected.
1 Noise detected in the received character in SCI1D.
1
FE
Framing Error Flag — FE is set at the same time as RDRF when the receiver detects a logic 0 where the stop
bit was expected. This suggests the receiver was not properly aligned to a character frame. To clear FE, read
SCI1S1 with FE = 1 and then read the SCI data register (SCI1D).
0 No framing error detected. This does not guarantee the framing is correct.
1 Framing error.
0
PF
Parity Error Flag — PF is set at the same time as RDRF when parity is enabled (PE = 1) and the parity bit in
the received character does not agree with the expected parity value. To clear PF, read SCI1S1 and then read
the SCI data register (SCI1D).
0 No parity error.
1 Parity error.
Table 12-5. SCI1S1 Register Field Descriptions (continued)
Field Description
Serial Communications Interface (S08SCIV1)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 155
12.2.5 SCI Status Register 2 (SCI1S2)
This register has one read-only status flag. Writes have no effect.
12.2.6 SCI Control Register 3 (SCI1C3)
76543210
R0000000RAF
W
Reset 00000000
= Unimplemented or Reserved
Figure 12-8. SCI Status Register 2 (SCI1S2)
Table 12-6. SCI1S2 Register Field Descriptions
Field Description
0
RAF
Receiver Active Flag — RAF is set when the SCI receiver detects the beginning of a valid start bit, and RAF is
cleared automatically when the receiver detects an idle line. This status flag can be used to check whether an
SCI character is being received before instructing the MCU to go to stop mode.
0 SCI receiver idle waiting for a start bit.
1 SCI receiver active (RxD input not idle).
76543210
RR8
T8 TXDIR
0
ORIE NEIE FEIE PEIE
W
Reset 00000000
= Unimplemented or Reserved
Figure 12-9. SCI Control Register 3 (SCI1C3)
Table 12-7. SCI1C3 Register Field Descriptions
Field Description
7
R8
Ninth Data Bit for Receiver — When the SCI is configured for 9-bit data (M = 1), R8 can be thought of as a
ninth receive data bit to the left of the MSB of the buffered data in the SCI1D register. When reading 9-bit data,
read R8 before reading SCI1D because reading SCI1D completes automatic flag clearing sequences which
could allow R8 and SCI1D to be overwritten with new data.
6
T8
Ninth Data Bit for Transmitter — When the SCI is configured for 9-bit data (M = 1), T8 may be thought of as a
ninth transmit data bit to the left of the MSB of the data in the SCI1D register. When writing 9-bit data, the entire
9-bit value is transferred to the SCI shift register after SCI1D is written so T8 should be written (if it needs to
change from its previous value) before SCI1D is written. If T8 does not need to change in the new value (such
as when it is used to generate mark or space parity), it need not be written each time SCI1D is written.
5
TXDIR
TxD Pin Direction in Single-Wire Mode — When the SCI is configured for single-wire half-duplex operation
(LOOPS = RSRC = 1), this bit determines the direction of data at the TxD pin.
0 TxD pin is an input in single-wire mode.
1 TxD pin is an output in single-wire mode.
Serial Communications Interface (S08SCIV1)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
156 Freescale Semiconductor
12.2.7 SCI Data Register (SCI1D)
This register is actually two separate registers. Reads return the contents of the read-only receive data
buffer and writes go to the write-only transmit data buffer. Reads and writes of this register are also
involved in the automatic flag clearing mechanisms for the SCI status flags.
3
ORIE
Overrun Interrupt Enable — This bit enables the overrun flag (OR) to generate hardware interrupt requests.
0 OR interrupts disabled (use polling).
1 Hardware interrupt requested when OR = 1.
2
NEIE
Noise Error Interrupt Enable — This bit enables the noise flag (NF) to generate hardware interrupt requests.
0 NF interrupts disabled (use polling).
1 Hardware interrupt requested when NF = 1.
1
FEIE
Framing Error Interrupt Enable — This bit enables the framing error flag (FE) to generate hardware interrupt
requests.
0 FE interrupts disabled (use polling).
1 Hardware interrupt requested when FE = 1.
0
PEIE
Parity Error Interrupt Enable — This bit enables the parity error flag (PF) to generate hardware interrupt
requests.
0 PF interrupts disabled (use polling).
1 Hardware interrupt requested when PF = 1.
76543210
RR7R6R5R4R3R2R1R0
WT7T6T5T4T3T2T1T0
Reset 00000000
Figure 12-10. SCI Data Register (SCI1D)
Table 12-7. SCI1C3 Register Field Descriptions (continued)
Field Description
Serial Communications Interface (S08SCIV1)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 157
12.3 Functional Description
The SCI allows full-duplex, asynchronous, NRZ serial communication among the MCU and remote
devices, including other MCUs. The SCI comprises a baud rate generator, transmitter, and receiver block.
The transmitter and receiver operate independently, although they use the same baud rate generator. During
normal operation, the MCU monitors the status of the SCI, writes the data to be transmitted, and processes
received data. The following describes each of the blocks of the SCI.
12.3.1 Baud Rate Generation
As shown in Figure 12-11, the clock source for the SCI baud rate generator is the bus-rate clock.
Figure 12-11. SCI Baud Rate Generation
SCI communications require the transmitter and receiver (which typically derive baud rates from
independent clock sources) to use the same baud rate. Allowed tolerance on this baud frequency depends
on the details of how the receiver synchronizes to the leading edge of the start bit and how bit sampling is
performed.
The MCU resynchronizes to bit boundaries on every high-to-low transition, but in the worst case, there are
no such transitions in the full 10- or 11-bit time character frame so any mismatch in baud rate is
accumulated for the whole character time. For a Freescale Semiconductor SCI system whose bus
frequency is driven by a crystal, the allowed baud rate mismatch is about ±4.5 percent for 8-bit data format
and about ±4 percent for 9-bit data format. Although baud rate modulo divider settings do not always
produce baud rates that exactly match standard rates, it is normally possible to get within a few percent,
which is acceptable for reliable communications.
12.3.2 Transmitter Functional Description
This section describes the overall block diagram for the SCI transmitter (Figure 12-1), as well as
specialized functions for sending break and idle characters.
The transmitter is enabled by setting the TE bit in SCI1C2. This queues a preamble character that is one
full character frame of the idle state. The transmitter then remains idle until data is available in the transmit
data buffer. Programs store data into the transmit data buffer by writing to the SCI data register (SCI1D).
The central element of the SCI transmitter is the transmit shift register that is either 10 or 11 bits long
depending on the setting in the M control bit. For the remainder of this section, we will assume M = 0,
selecting the normal 8-bit data mode. In 8-bit data mode, the shift register holds a start bit, eight data bits,
and a stop bit. When the transmit shift register is available for a new SCI character, the value waiting in
SBR12:SBR0
DIVIDE BY
Tx BAUD RATE
Rx SAMPLING CLOCK
(16 × BAUD RATE)
BAUD RATE GENERATOR
OFF IF [SBR12:SBR0] = 0
BUSCLK
BAUD RATE = BUSCLK
[SBR12:SBR0] × 16
16
MODULO DIVIDE BY
(1 THROUGH 8191)
Serial Communications Interface (S08SCIV1)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
158 Freescale Semiconductor
the transmit data register is transferred to the shift register (synchronized with the baud rate clock) and the
transmit data register empty (TDRE) status flag is set to indicate another character may be written to the
transmit data buffer at SCI1D.
If no new character is waiting in the transmit data buffer after a stop bit is shifted out the TxD1 pin, the
transmitter sets the transmit complete flag and enters an idle mode, with TxD1 high, waiting for more
characters to transmit.
Writing 0 to TE does not immediately release the pin to be a general-purpose I/O pin. Any transmit activity
that is in progress must first be completed. This includes data characters in progress, queued idle
characters, and queued break characters.
12.3.2.1 Send Break and Queued Idle
The SBK control bit in SCI1C2 is used to send break characters which were originally used to gain the
attention of old teletype receivers. Break characters are a full character time of logic 0 (10 bit times
including the start and stop bits). Normally, a program would wait for TDRE to become set to indicate the
last character of a message has moved to the transmit shifter, then write 1 and then write 0 to the SBK bit.
This action queues a break character to be sent as soon as the shifter is available. If SBK is still 1 when the
queued break moves into the shifter (synchronized to the baud rate clock), an additional break character is
queued. If the receiving device is another Freescale Semiconductor SCI, the break characters will be
received as 0s in all eight data bits and a framing error (FE = 1) occurs.
When idle-line wakeup is used, a full character time of idle (logic 1) is needed between messages to wake
up any sleeping receivers. Normally, a program would wait for TDRE to become set to indicate the last
character of a message has moved to the transmit shifter, then write 0 and then write 1 to the TE bit. This
action queues an idle character to be sent as soon as the shifter is available. As long as the character in the
shifter does not finish while TE = 0, the SCI transmitter never actually releases control of the TxD1 pin. If
there is a possibility of the shifter finishing while TE = 0, set the general-purpose I/O controls so the pin
that is shared with TxD1 is an output driving a logic 1. This ensures that the TxD1 line will look like a
normal idle line even if the SCI loses control of the port pin between writing 0 and then 1 to TE.
12.3.3 Receiver Functional Description
In this section, the data sampling technique used to reconstruct receiver data is described in more detail;
two variations of the receiver wakeup function are explained. (The receiver block diagram is shown in
Figure 12-2.)
The receiver is enabled by setting the RE bit in SCI1C2. Character frames consist of a start bit of logic 0,
eight (or nine) data bits (LSB first), and a stop bit of logic 1. For information about 9-bit data mode, refer
to Section 12.3.5.1, “8- and 9-Bit Data Modes.” For the remainder of this discussion, we assume the SCI
is configured for normal 8-bit data mode.
After receiving the stop bit into the receive shifter, and provided the receive data register is not already full,
the data character is transferred to the receive data register and the receive data register full (RDRF) status
flag is set. If RDRF was already set indicating the receive data register (buffer) was already full, the overrun
(OR) status flag is set and the new data is lost. Because the SCI receiver is double-buffered, the program
Serial Communications Interface (S08SCIV1)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 159
has one full character time after RDRF is set before the data in the receive data buffer must be read to avoid
a receiver overrun.
When a program detects that the receive data register is full (RDRF = 1), it gets the data from the receive
data register by reading SCI1D. The RDRF flag is cleared automatically by a 2-step sequence which is
normally satisfied in the course of the user’s program that handles receive data. Refer to Section 12.3.4,
“Interrupts and Status Flags,” for more details about flag clearing.
12.3.3.1 Data Sampling Technique
The SCI receiver uses a 16×baud rate clock for sampling. The receiver starts by taking logic level samples
at 16 times the baud rate to search for a falling edge on the RxD1 serial data input pin. A falling edge is
defined as a logic 0 sample after three consecutive logic 1 samples. The 16× baud rate clock is used to
divide the bit time into 16 segments labeled RT1 through RT16. When a falling edge is located, three more
samples are taken at RT3, RT5, and RT7 to make sure this was a real start bit and not merely noise. If at
least two of these three samples are 0, the receiver assumes it is synchronized to a receive character.
The receiver then samples each bit time, including the start and stop bits, at RT8, RT9, and RT10 to
determine the logic level for that bit. The logic level is interpreted to be that of the majority of the samples
taken during the bit time. In the case of the start bit, the bit is assumed to be 0 if at least two of the samples
at RT3, RT5, and RT7 are 0 even if one or all of the samples taken at RT8, RT9, and RT10 are 1s. If any
sample in any bit time (including the start and stop bits) in a character frame fails to agree with the logic
level for that bit, the noise flag (NF) will be set when the received character is transferred to the receive
data buffer.
The falling edge detection logic continuously looks for falling edges, and if an edge is detected, the sample
clock is resynchronized to bit times. This improves the reliability of the receiver in the presence of noise
or mismatched baud rates. It does not improve worst case analysis because some characters do not have
any extra falling edges anywhere in the character frame.
In the case of a framing error, provided the received character was not a break character, the sampling logic
that searches for a falling edge is filled with three logic 1 samples so that a new start bit can be detected
almost immediately.
In the case of a framing error, the receiver is inhibited from receiving any new characters until the framing
error flag is cleared. The receive shift register continues to function, but a complete character cannot
transfer to the receive data buffer if FE is still set.
12.3.3.2 Receiver Wakeup Operation
Receiver wakeup is a hardware mechanism that allows an SCI receiver to ignore the characters in a
message that is intended for a different SCI receiver. In such a system, all receivers evaluate the first
character(s) of each message, and as soon as they determine the message is intended for a different
receiver, they write logic 1 to the receiver wake up (RWU) control bit in SCI1C2. When RWU = 1, it
inhibits setting of the status flags associated with the receiver, thus eliminating the software overhead for
handling the unimportant message characters. At the end of a message, or at the beginning of the next
message, all receivers automatically force RWU to 0 so all receivers wake up in time to look at the first
character(s) of the next message.
Serial Communications Interface (S08SCIV1)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
160 Freescale Semiconductor
12.3.3.2.1 Idle-Line Wakeup
When WAKE = 0, the receiver is configured for idle-line wakeup. In this mode, RWU is cleared
automatically when the receiver detects a full character time of the idle-line level. The M control bit selects
8-bit or 9-bit data mode that determines how many bit times of idle are needed to constitute a full character
time (10 or 11 bit times because of the start and stop bits). The idle-line type (ILT) control bit selects one
of two ways to detect an idle line:
• When ILT = 0, the idle bit counter starts after the start bit so the stop bit and any logic 1s at the end
of a character count toward the full character time of idle.
• When ILT = 1, the idle bit counter doesn’t start until after a stop bit time, so the idle detection is
not affected by the data in the last character of the previous message.
12.3.3.2.2 Address-Mark Wakeup
When WAKE = 1, the receiver is configured for address-mark wakeup. In this mode, RWU is cleared
automatically when the receiver detects a logic 1 in the most significant bit of a received character (eighth
bit in M = 0 mode and ninth bit in M = 1 mode).
12.3.4 Interrupts and Status Flags
The SCI system has three separate interrupt vectors to reduce the amount of software needed to isolate the
cause of the interrupt. One interrupt vector is associated with the transmitter for TDRE and TC events.
Another interrupt vector is associated with the receiver for RDRF and IDLE events, and a third vector is
used for OR, NF, FE, and PF error conditions. Each of these eight interrupt sources can be separately
masked by local interrupt enable masks. The flags can still be polled by software when the local masks are
cleared to disable generation of hardware interrupt requests.
The SCI transmitter has two status flags that optionally can generate hardware interrupt requests. Transmit
data register empty (TDRE) indicates when there is room in the transmit data buffer to write another
transmit character to SCI1D. If the transmit interrupt enable (TIE) bit is set, a hardware interrupt will be
requested whenever TDRE = 1. Transmit complete (TC) indicates that the transmitter is finished
transmitting all data, preamble, and break characters and is idle with TxD1 high. This flag is often used in
systems with modems to determine when it is safe to turn off the modem. If the transmit complete interrupt
enable (TCIE) bit is set, a hardware interrupt will be requested whenever TC = 1. Instead of hardware
interrupts, software polling may be used to monitor the TDRE and TC status flags if the corresponding TIE
or TCIE local interrupt masks are 0s.
When a program detects that the receive data register is full (RDRF = 1), it gets the data from the receive
data register by reading SCI1D. The RDRF flag is cleared by reading SCI1S1 while RDRF = 1 and then
reading SCI1D.
When polling is used, this sequence is naturally satisfied in the normal course of the user program. If
hardware interrupts are used, SCI1S1 must be read in the interrupt service routine (ISR). Normally, this is
done in the ISR anyway to check for receive errors, so the sequence is automatically satisfied.
The IDLE status flag includes logic that prevents it from getting set repeatedly when the RxD1 line remains
idle for an extended period of time. IDLE is cleared by reading SCI1S1 while IDLE = 1 and then reading
Serial Communications Interface (S08SCIV1)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 161
SCI1D. After IDLE has been cleared, it cannot become set again until the receiver has received at least one
new character and has set RDRF.
If the associated error was detected in the received character that caused RDRF to be set, the error flags —
noise flag (NF), framing error (FE), and parity error flag (PF) — get set at the same time as RDRF. These
flags are not set in overrun cases.
If RDRF was already set when a new character is ready to be transferred from the receive shifter to the
receive data buffer, the overrun (OR) flag gets set instead and the data and any associated NF, FE, or PF
condition is lost.
12.3.5 Additional SCI Functions
The following sections describe additional SCI functions.
12.3.5.1 8- and 9-Bit Data Modes
The SCI system (transmitter and receiver) can be configured to operate in 9-bit data mode by setting the
M control bit in SCI1C1. In 9-bit mode, there is a ninth data bit to the left of the MSB of the SCI data
register. For the transmit data buffer, this bit is stored in T8 in SCI1C3. For the receiver, the ninth bit is
held in R8 in SCI1C3.
For coherent writes to the transmit data buffer, write to the T8 bit before writing to SCI1D.
If the bit value to be transmitted as the ninth bit of a new character is the same as for the previous character,
it is not necessary to write to T8 again. When data is transferred from the transmit data buffer to the
transmit shifter, the value in T8 is copied at the same time data is transferred from SCI1D to the shifter.
9-bit data mode typically is used in conjunction with parity to allow eight bits of data plus the parity in the
ninth bit. Or it is used with address-mark wakeup so the ninth data bit can serve as the wakeup bit. In
custom protocols, the ninth bit can also serve as a software-controlled marker.
12.3.5.2 Stop Mode Operation
During all stop modes, clocks to the SCI module are halted.
In stop1 and stop2 modes, all SCI register data is lost and must be re-initialized upon recovery from these
two stop modes.
No SCI module registers are affected in stop3 mode.
Because the clocks are halted, the SCI module will resume operation upon exit from stop (only in stop3
mode). Software should ensure stop mode is not entered while there is a character being transmitted out of
or received into the SCI module.
12.3.5.3 Loop Mode
When LOOPS = 1, the RSRC bit in the same register chooses between loop mode (RSRC = 0) or
single-wire mode (RSRC = 1). Loop mode is sometimes used to check software, independent of
connections in the external system, to help isolate system problems. In this mode, the transmitter output is
Serial Communications Interface (S08SCIV1)
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
162 Freescale Semiconductor
internally connected to the receiver input and the RxD1 pin is not used by the SCI, so it reverts to a
general-purpose port I/O pin.
12.3.5.4 Single-Wire Operation
When LOOPS = 1, the RSRC bit in the same register chooses between loop mode (RSRC = 0) or
single-wire mode (RSRC = 1). Single-wire mode is used to implement a half-duplex serial connection.
The receiver is internally connected to the transmitter output and to the TxD1 pin. The RxD1 pin is not
used and reverts to a general-purpose port I/O pin.
In single-wire mode, the TXDIR bit in SCI1C3 controls the direction of serial data on the TxD1 pin. When
TXDIR = 0, the TxD1 pin is an input to the SCI receiver and the transmitter is temporarily disconnected
from the TxD1 pin so an external device can send serial data to the receiver. When TXDIR = 1, the TxD1
pin is an output driven by the transmitter. In single-wire mode, the internal loop back connection from the
transmitter to the receiver causes the receiver to receive characters that are sent out by the transmitter.
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 163
Chapter 13
Serial Peripheral Interface (S08SPIV3)
The SPI is only available on the MC9S08RGxx versions of this family of microcontrollers. The SPI pins
are shared with PTC4-PTC7 port pins. When the SPI is enabled these pins are controlled by the SPI
module.
Figure 13-1. MC9S08RC/RD/RE/RG Block Diagram Highlighting SPI Block and Pins
PTD3
PTD4/ACMP1–
PTD5/ACMP1+
PTD6/TPM1CH0
PTC1/KBI2P1
PTC0/KBI2P0
VSS
VDD
PTB3
PTB2
PTA7/KBI1P7–
PTB0/TxD1
PTB1/RxD1
PTD2/IRQ
PTD1/RESET
PTD0/BKGD/MS
PTC7/SS1
PTC6/SPSCK1
PTC5/MISO1
PTC4/MOSI1
PTC3/KBI2P3
PTC2/KBI2P2
PORT A
PORT C
PORT D
PORT B
8-BIT KEYBOARD
INTERRUPT MODULE (KBI1)
SERIAL PERIPHERAL
INTERFACE MODULE (SPI1)
USER FLASH
USER RAM
(RC/RD/RE/RG32/60 = 2048 BYTES)
DEBUG
MODULE (DBG)
(RC/RD/RE/RG60 = 63,364 BYTES)
HCS08 CORE
NOTES
NOTES 1, 5
2-CHANNEL TIMER/PWM
MODULE (TPM1)
PTE7–
PORT E
PTB5
PTB4
PTE6
PTB7/TPM1CH1
MODULE (ACMP1)
HCS08 SYSTEM CONTROL
RESETS AND INTERRUPTS
MODES OF OPERATION
POWER MANAGEMENT
VOLTAGE
REGULATOR
RTI
ANALOG COMPARATOR
COP
IRQ LVD
INTERNAL BUS
LOW-POWER OSCILLATOR
INTERFACE MODULE (SCI1)
SERIAL COMMUNICATIONS
7
PTA1/KBI1P1
8
PTE0
NOTE 1
NOTES1, 2
NOTE 1
(RC/RD/RE/RG32 = 32,768 BYTES)
(RC/RD/RE8/16 = 1024 BYTES)
(RC/RD/RE16 = 16,384 BYTES)
XTAL
EXTAL
CARRIER MODULATOR
TIMER MODULE (CMT)
1, 3, 4
4-BIT KEYBOARD
INTERRUPT MODULE (KBI2)
IRO NOTE 5
PTA0/KBI1P0
(RC/RD/RE8 = 8192 BYTES)
BDC
CPU
NOTES:
1. Port pins are software configurable with pullup device if input port
2. PTA0 does not have a clamp diode to VDD. PTA0 should not be driven above VDD. Also, PTA0 does not pullup to VDD when internal
pullup is enabled.
3. IRQ pin contains software configurable pullup/pulldown device if IRQ enabled (IRQPE = 1)
4. The RESET pin contains integrated pullup device enabled if reset enabled (RSTPE = 1)
5. High current drive
6. Pins PTA[7:4] contain both pullup and pulldown devices. Pulldown enabled when KBI is enabled (KBIPEn = 1) and rising edge is
selected (KBEDGn = 1).
Serial Peripheral Interface (SPI) Module
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
164 Freescale Semiconductor
13.1 Features
Features of the SPI module include:
• Master or slave mode operation
• Full-duplex or single-wire bidirectional option
• Programmable transmit bit rate
• Double-buffered transmit and receive
• Serial clock phase and polarity options
• Slave select output
• Selectable MSB-first or LSB-first shifting
13.2 Block Diagrams
This section includes block diagrams showing SPI system connections, the internal organization of the SPI
module, and the SPI clock dividers that control the master mode bit rate.
13.2.1 SPI System Block Diagram
Figure 13-2 shows the SPI modules of two MCUs connected in a master-slave arrangement. The master
device initiates all SPI data transfers. During a transfer, the master shifts data out (on the MOSI1 pin) to
the slave while simultaneously shifting data in (on the MISO1 pin) from the slave. The transfer effectively
exchanges the data that was in the SPI shift registers of the two SPI systems. The SPSCK1 signal is a clock
output from the master and an input to the slave. The slave device must be selected by a low level on the
slave select input (SS1 pin). In this system, the master device has configured its SS1 pin as an optional
slave select output.
Figure 13-2. SPI System Connections
76543210
SPI SHIFTER
CLOCK
GENERATOR
76543210
SPI SHIFTER
SS1
SPSCK1
MISO1
MOSI1
SS1
SPSCK1
MISO1
MOSI1
MASTER SLAVE
Serial Peripheral Interface (SPI) Module
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 165
The most common uses of the SPI system include connecting simple shift registers for adding input or
output ports or connecting small peripheral devices such as serial A/D or D/A converters. Although
Figure 13-2 shows a system where data is exchanged between two MCUs, many practical systems involve
simpler connections where data is unidirectionally transferred from the master MCU to a slave or from a
slave to the master MCU.
13.2.2 SPI Module Block Diagram
Figure 13-3 is a block diagram of the SPI module. The central element of the SPI is the SPI shift register.
Data is written to the double-buffered transmitter (write to SPI1D) and gets transferred to the SPI shift
register at the start of a data transfer. After shifting in a byte of data, the data is transferred into the
double-buffered receiver where it can be read (read from SPI1D). Pin multiplexing logic controls
connections between MCU pins and the SPI module.
When the SPI is configured as a master, the clock output is routed to the SPSCK1 pin, the shifter output is
routed to MOSI1, and the shifter input is routed from the MISO1 pin.
When the SPI is configured as a slave, the SPSCK1 pin is routed to the clock input of the SPI, the shifter
output is routed to MISO1, and the shifter input is routed from the MOSI1 pin.
In the external SPI system, simply connect all SPSCK pins to each other, all MISO pins together, and all
MOSI pins together. Peripheral devices often use slightly different names for these pins.
Serial Peripheral Interface (SPI) Module
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
166 Freescale Semiconductor
Figure 13-3. SPI Module Block Diagram
SPI SHIFT REGISTER
SHIFT
CLOCK
SHIFT
DIRECTION
Rx BUFFER
FULL
Tx BUFFER
EMPTY
SHIFT
OUT
SHIFT
IN
ENABLE
SPI SYSTEM
CLOCK
LOGIC
CLOCK GENERATOR
BUS RATE
CLOCK
MASTER/SLAVE
MODE SELECT
MODE FAULT
DETECTION
MASTER CLOCK
SLAVE CLOCK
SPI
INTERRUPT
REQUEST
PIN CONTROL
M
S
MASTER/
SLAVE
MOSI1
(MOMI)
MISO1
(SISO)
SPSCK1
SS1
M
S
S
M
<st-blue>
<st-blue>
<st-blue>L
<st-blue>
<st-blue> <st-blue>
<st-blue>
<st-blue>
<st-blue>
<st-blue>
<st-blue>
<st-blue>
SPIBR
Tx BUFFER (WRITE SPI1D)
Rx BUFFER (READ SPI1D)
Serial Peripheral Interface (SPI) Module
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 167
13.2.3 SPI Baud Rate Generation
As shown in Figure 13-4, the clock source for the SPI baud rate generator is the bus clock. The three
prescale bits (SPPR2:SPPR1:SPPR0) choose a prescale divisor of 1, 2, 3, 4, 5, 6, 7, or 8. The three rate
select bits (SPR2:SPR1:SPR0) divide the output of the prescaler stage by 2, 4, 8, 16, 32, 64, 128, or 256
to get the internal SPI master mode bit-rate clock.
Figure 13-4. SPI Baud Rate Generation
13.3 Functional Description
An SPI transfer is initiated by checking for the SPI transmit buffer empty flag (SPTEF = 1) and then
writing a byte of data to the SPI data register (SPI1D) in the master SPI device. When the SPI shift register
is available, this byte of data is moved from the transmit data buffer to the shifter, SPTEF is set to indicate
there is room in the buffer to queue another transmit character if desired, and the SPI serial transfer starts.
During the SPI transfer, data is sampled (read) on the MISO1 pin at one SPSCK edge and shifted, changing
the bit value on the MOSI1 pin, one-half SPSCK cycle later. After eight SPSCK cycles, the data that was
in the shift register of the master has been shifted out the MOSI1 pin to the slave while eight bits of data
were shifted in the MISO1 pin into the master’s shift register. At the end of this transfer, the received data
byte is moved from the shifter into the receive data buffer and SPRF is set to indicate the data can be read
by reading SPI1D. If another byte of data is waiting in the transmit buffer at the end of a transfer, it is
moved into the shifter, SPTEF is set, and a new transfer is started.
Normally, SPI data is transferred most significant bit (MSB) first. If the least significant bit first enable
(LSBFE) bit is set, SPI data is shifted LSB first.
When the SPI is configured as a slave, its SS1 pin must be driven low before a transfer starts and SS1 must
stay low throughout the transfer. If a clock format where CPHA = 0 is selected, SS1 must be driven to a
logic 1 between successive transfers. If CPHA = 1, SS1 may remain low between successive transfers. See
Section 13.3.1, “SPI Clock Formats,” for more details.
Because the transmitter and receiver are double buffered, a second byte, in addition to the byte currently
being shifted out, can be queued into the transmit data buffer, and a previously received character can be
in the receive data buffer while a new character is being shifted in. The SPTEF flag indicates when the
transmit buffer has room for a new character. The SPRF flag indicates when a received character is
available in the receive data buffer. The received character must be read out of the receive buffer (read
SPI1D) before the next transfer is finished or a receive overrun error results.
In the case of a receive overrun, the new data is lost because the receive buffer still held the previous
character and was not ready to accept the new data. There is no indication for such an overrun condition
so the application system designer must ensure that previous data has been read from the receive buffer
before a new transfer is initiated.
DIVIDE BY
2, 4, 8, 16, 32, 64, 128, or 256
DIVIDE BY
1, 2, 3, 4, 5, 6, 7, or 8
PRESCALER CLOCK RATE DIVIDER
SPPR2:SPPR1:SPPR0 SPR2:SPR1:SPR0
BUS CLOCK
MASTER
SPI
BIT RATE
Serial Peripheral Interface (SPI) Module
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
168 Freescale Semiconductor
13.3.1 SPI Clock Formats
To accommodate a wide variety of synchronous serial peripherals from different manufacturers, the SPI
system has a clock polarity (CPOL) bit and a clock phase (CPHA) control bit to select one of four clock
formats for data transfers. CPOL selectively inserts an inverter in series with the clock. CPHA chooses
between two different clock phase relationships between the clock and data.
Figure 13-5 shows the clock formats when CPHA = 1. At the top of the figure, the eight bit times are shown
for reference with bit 1 starting at the first SPSCK edge and bit 8 ending one-half SPSCK cycle after the
sixteenth SPSCK edge. The MSB first and LSB first lines show the order of SPI data bits depending on the
setting in LSBFE. Both variations of SPSCK polarity are shown, but only one of these waveforms applies
for a specific transfer, depending on the value in CPOL. The SAMPLE IN waveform applies to the MOSI
input of a slave or the MISO input of a master. The MOSI waveform applies to the MOSI output pin from
a master and the MISO waveform applies to the MISO output from a slave. The SS OUT waveform applies
to the slave select output from a master (provided MODFEN and SSOE = 1). The master SS output goes
to active low one-half SPSCK cycle before the start of the transfer and goes back high at the end of the
eighth bit time of the transfer. The SS IN waveform applies to the slave select input of a slave.
Figure 13-5. SPI Clock Formats (CPHA = 1)
BIT TIME #
(REFERENCE)
MSB FIRST
LSB FIRST
SPSCK
(CPOL = 0)
SPSCK
(CPOL = 1)
SAMPLE IN
(MISO OR MOSI)
MOSI
(MASTER OUT)
MISO
(SLAVE OUT)
SS OUT
(MASTER)
SS IN
(SLAVE)
BIT 7
BIT 0
BIT 6
BIT 1
BIT 2
BIT 5
BIT 1
BIT 6
BIT 0
BIT 7
12 67 8
...
...
...
Serial Peripheral Interface (SPI) Module
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 169
When CPHA = 1, the slave begins to drive its MISO output when SS1 goes to active low, but the data is
not defined until the first SPSCK edge. The first SPSCK edge shifts the first bit of data from the shifter
onto the MOSI output of the master and the MISO output of the slave. The next SPSCK edge causes both
the master and the slave to sample the data bit values on their MISO and MOSI inputs, respectively. At the
third SPSCK edge, the SPI shifter shifts one bit position which shifts in the bit value that was just sampled,
and shifts the second data bit value out the other end of the shifter to the MOSI and MISO outputs of the
master and slave, respectively. When CHPA = 1, the slave’s SS input is not required to go to its inactive
high level between transfers.
Figure 13-6 shows the clock formats when CPHA = 0. At the top of the figure, the eight bit times are shown
for reference with bit 1 starting as the slave is selected (SS IN goes low), and bit 8 ends at the last SPSCK
edge. The MSB first and LSB first lines show the order of SPI data bits depending on the setting in LSBFE.
Both variations of SPSCK polarity are shown, but only one of these waveforms applies for a specific
transfer, depending on the value in CPOL. The SAMPLE IN waveform applies to the MOSI input of a
slave or the MISO input of a master. The MOSI waveform applies to the MOSI output pin from a master
and the MISO waveform applies to the MISO output from a slave. The SS OUT waveform applies to the
slave select output from a master (provided MODFEN and SSOE = 1). The master SS output goes to active
low at the start of the first bit time of the transfer and goes back high one-half SPSCK cycle after the end
of the eighth bit time of the transfer. The SS IN waveform applies to the slave select input of a slave.
Figure 13-6. SPI Clock Formats (CPHA = 0)
BIT TIME #
(REFERENCE)
MSB FIRST
LSB FIRST
SPSCK
(CPOL = 0)
SPSCK
(CPOL = 1)
SAMPLE IN
(MISO OR MOSI)
MOSI
(MASTER OUT)
MISO
(SLAVE OUT)
SS OUT
(MASTER)
SS IN
(SLAVE)
BIT 7
BIT 0
BIT 6
BIT 1
BIT 2
BIT 5
BIT 1
BIT 6
BIT 0
BIT 7
12 67 8...
...
...
Serial Peripheral Interface (SPI) Module
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
170 Freescale Semiconductor
When CPHA = 0, the slave begins to drive its MISO output with the first data bit value (MSB or LSB
depending on LSBFE) when SS1 goes to active low. The first SPSCK edge causes both the master and the
slave to sample the data bit values on their MISO and MOSI inputs, respectively. At the second SPSCK
edge, the SPI shifter shifts one bit position which shifts in the bit value that was just sampled and shifts the
second data bit value out the other end of the shifter to the MOSI and MISO outputs of the master and
slave, respectively. When CPHA = 0, the slave’s SS input must go to its inactive high level between
transfers.
13.3.2 SPI Pin Controls
The SPI optionally shares four port pins. The function of these pins depends on the settings of SPI control
bits. When the SPI is disabled (SPE = 0), these four pins revert to being general-purpose port I/O pins that
are not controlled by the SPI.
13.3.2.1 SPSCK1 — SPI Serial Clock
When the SPI is enabled as a slave, this pin is the serial clock input. When the SPI is enabled as a master,
this pin is the serial clock output.
13.3.2.2 MOSI1 — Master Data Out, Slave Data In
When the SPI is enabled as a master and SPI pin control zero (SPC0) is 0 (not bidirectional mode), this
pin is the serial data output. When the SPI is enabled as a slave and SPC0 = 0, this pin is the serial data
input. If SPC0 = 1 to select single-wire bidirectional mode, and master mode is selected, this pin becomes
the bidirectional data I/O pin (MOMI). Also, the bidirectional mode output enable bit determines whether
the pin acts as an input (BIDIROE = 0) or an output (BIDIROE = 1). If SPC0 = 1 and slave mode is
selected, this pin is not used by the SPI and reverts to being a general-purpose port I/O pin.
13.3.2.3 MISO1 — Master Data In, Slave Data Out
When the SPI is enabled as a master and SPI pin control zero (SPC0) is 0 (not bidirectional mode), this
pin is the serial data input. When the SPI is enabled as a slave and SPC0 = 0, this pin is the serial data
output. If SPC0 = 1 to select single-wire bidirectional mode, and slave mode is selected, this pin becomes
the bidirectional data I/O pin (SISO) and the bidirectional mode output enable bit determines whether the
pin acts as an input (BIDIROE = 0) or an output (BIDIROE = 1). If SPC0 = 1 and master mode is selected,
this pin is not used by the SPI and reverts to being a general-purpose port I/O pin.
13.3.2.4 SS1 — Slave Select
When the SPI is enabled as a slave, this pin is the low-true slave select input. When the SPI is enabled as
a master and mode fault enable is off (MODFEN = 0), this pin is not used by the SPI and reverts to being
a general-purpose port I/O pin. When the SPI is enabled as a master and MODFEN = 1, the slave select
output enable bit determines whether this pin acts as the mode fault input (SSOE = 0) or as the slave select
output (SSOE = 1).
Serial Peripheral Interface (SPI) Module
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 171
13.3.3 SPI Interrupts
There are three flag bits, two interrupt mask bits, and one interrupt vector associated with the SPI system.
The SPI interrupt enable mask (SPIE) enables interrupts from the SPI receiver full flag (SPRF) and mode
fault flag (MODF). The SPI transmit interrupt enable mask (SPTIE) enables interrupts from the SPI
transmit buffer empty flag (SPTEF). When one of the flag bits is set, and the associated interrupt mask bit
is set, a hardware interrupt request is sent to the CPU. If the interrupt mask bits are cleared, software can
poll the associated flag bits instead of using interrupts. The SPI interrupt service routine (ISR) should
check the flag bits to determine what event caused the interrupt. The service routine should also clear the
flag bit(s) before returning from the ISR (usually near the beginning of the ISR).
13.3.4 Mode Fault Detection
A mode fault occurs and the mode fault flag (MODF) becomes set when a master SPI device detects an
error on the SS1 pin (provided the SS1 pin is configured as the mode fault input signal). The SS1 pin is
configured to be the mode fault input signal when MSTR = 1, mode fault enable is set (MODFEN = 1),
and slave select output enable is clear (SSOE = 0).
The mode fault detection feature can be used in a system where more than one SPI device might become
a master at the same time. The error is detected when a master’s SS1 pin is low, indicating that some other
SPI device is trying to address this master as if it were a slave. This could indicate a harmful output driver
conflict, so the mode fault logic is designed to disable all SPI output drivers when such an error is detected.
When a mode fault is detected, MODF is set and MSTR is cleared to change the SPI configuration back
to slave mode. The output drivers on the SPSCK1, MOSI1, and MISO1 (if not bidirectional mode) are
disabled.
MODF is cleared by reading it while it is set, then writing to the SPI control register 1 (SPI1C1). User
software should verify the error condition has been corrected before changing the SPI back to master
mode.
13.4 SPI Registers and Control Bits
The SPI has five 8-bit registers to select SPI options, control baud rate, report SPI status, and for
transmit/receive data.
Refer to the direct-page register summary in the Memory chapter of this data sheet for the absolute address
assignments for all SPI registers. This section refers to registers and control bits only by their names, and
a Freescale-provided equate or header file is used to translate these names into the appropriate absolute
addresses.
Serial Peripheral Interface (SPI) Module
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
172 Freescale Semiconductor
13.4.1 SPI Control Register 1 (SPI1C1)
This read/write register includes the SPI enable control, interrupt enables, and configuration options.
Figure 13-7. SPI Control Register 1 (SPI1C1)
SPIE — SPI Interrupt Enable (for SPRF and MODF)
This is the interrupt enable for SPI receive buffer full (SPRF) and mode fault (MODF) events.
1 = When SPRF or MODF is 1, request a hardware interrupt.
0 = Interrupts from SPRF and MODF inhibited (use polling).
SPE — SPI System Enable
Disabling the SPI halts any transfer that is in progress, clears data buffers, and initializes internal state
machines. SPRF is cleared and SPTEF is set to indicate the SPI transmit data buffer is empty.
1 = SPI system enabled.
0 = SPI system inactive.
SPTIE — SPI Transmit Interrupt Enable
This is the interrupt enable bit for SPI transmit buffer empty (SPTEF).
1 = When SPTEF is 1, hardware interrupt requested.
0 = Interrupts from SPTEF inhibited (use polling).
MSTR — Master/Slave Mode Select
1 = SPI module configured as a master SPI device.
0 = SPI module configured as a slave SPI device.
CPOL — Clock Polarity
This bit effectively places an inverter in series with the clock signal from a master SPI or to a slave SPI
device. Refer to Section 13.3.1, “SPI Clock Formats,” for more details.
1 = Active-low SPI clock (idles high).
0 = Active-high SPI clock (idles low).
CPHA — Clock Phase
This bit selects one of two clock formats for different kinds of synchronous serial peripheral devices.
Refer to Section 13.3.1, “SPI Clock Formats,” for more details.
1 = First edge on SPSCK occurs at the start of the first cycle of an 8-cycle data transfer.
0 = First edge on SPSCK occurs at the middle of the first cycle of an 8-cycle data transfer.
Bit 7 654321Bit 0
Read: <st-blue>
SPIE
<st-blue>
SPE
<st-blue>
SPTIE
<st-blue>
MSTR
<st-blue>
CPOL
<st-blue>
CPHA
<st-blue>
SSOE
<st-blue>
LSBFE
Write:
Reset: 00000100
Serial Peripheral Interface (SPI) Module
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 173
SSOE — Slave Select Output Enable
This bit is used in combination with the mode fault enable (MODFEN) bit in SPCR2 and the
master/slave (MSTR) control bit to determine the function of the SS1 pin as shown in Table 13-1.
LSBFE — LSB First (Shifter Direction)
1 = SPI serial data transfers start with least significant bit.
0 = SPI serial data transfers start with most significant bit.
13.4.2 SPI Control Register 2 (SPI1C2)
This read/write register is used to control optional features of the SPI system. Bits 7, 6, 5, and 2 are not
implemented and always read 0.
Figure 13-8. SPI Control Register 2 (SPI1C2)
MODFEN — Master Mode-Fault Function Enable
When the SPI is configured for slave mode, this bit has no meaning or effect. (The SS1 pin is the slave
select input.) In master mode, this bit determines how the SS1 pin is used (refer to Table 13-1 for more
details).
1 = Mode fault function enabled, master SS1 pin acts as the mode fault input or the slave select
output.
0 = Mode fault function disabled, master SS1 pin reverts to general-purpose I/O not controlled by
SPI.
Table 13-1. SS1 Pin Function
MODFEN SSOE Master Mode Slave Mode
00
General-purpose I/O (not SPI) Slave select input
01
General-purpose I/O (not SPI) Slave select input
10
SS input for mode fault Slave select input
11
Automatic SS output Slave select input
Bit 7 6 54321Bit 0
Read: 0 0 0 <st-blue>
MODFEN
<st-blue>
BIDIROE
0<st-blue>
SPISWAI
<st-blue>
SPC0
Write:
Reset: 0 0 000000
= Unimplemented or Reserved
Serial Peripheral Interface (SPI) Module
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
174 Freescale Semiconductor
BIDIROE — Bidirectional Mode Output Enable
When bidirectional mode is enabled by SPI pin control 0 (SPC0) = 1, BIDIROE determines whether
the SPI data output driver is enabled to the single bidirectional SPI I/O pin. Depending on whether the
SPI is configured as a master or a slave, it uses either the MOSI1 (MOMI) or MISO1 (SISO) pin,
respectively, as the single SPI data I/O pin. When SPC0 = 0, BIDIROE has no meaning or effect.
1 = SPI I/O pin enabled as an output.
0 = Output driver disabled so SPI data I/O pin acts as an input.
SPISWAI — SPI Stop in Wait Mode
1 = SPI clocks stop when the MCU enters wait mode.
0 = SPI clocks continue to operate in wait mode.
SPC0 — SPI Pin Control 0
The SPC0 bit chooses single-wire bidirectional mode. If MSTR = 0 (slave mode), the SPI uses the
MISO1 (SISO) pin for bidirectional SPI data transfers. If MSTR = 1 (master mode), the SPI uses the
MOSI1 (MOMI) pin for bidirectional SPI data transfers. When SPC0 = 1, BIDIROE is used to enable
or disable the output driver for the single bidirectional SPI I/O pin.
1 = SPI configured for single-wire bidirectional operation.
0 = SPI uses separate pins for data input and data output.
13.4.3 SPI Baud Rate Register (SPI1BR)
This register is used to set the prescaler and bit rate divisor for an SPI master. This register may be read or
written at any time.
Figure 13-9. SPI Baud Rate Register (SPI1BR)
SPPR2:SPPR1:SPPR0 — SPI Baud Rate Prescale Divisor
This 3-bit field selects one of eight divisors for the SPI baud rate prescaler as shown in Table 13-2. The
input to this prescaler is the bus rate clock (BUSCLK). The output of this prescaler drives the input of
the SPI baud rate divider (see Figure 13-4).
Bit 7 654321Bit 0
Read: 0 <st-blue>
SPPR2
<st-blue>
SPPR1
<st-blue>
SPPR0
0<st-blue>
SPR2
<st-blue>
SPR1
<st-blue>
SPR0
Write:
Reset: 00000000
= Unimplemented or Reserved
Serial Peripheral Interface (SPI) Module
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 175
SPR2:SPR1:SPR0 — SPI Baud Rate Divisor
This 3-bit field selects one of eight divisors for the SPI baud rate divider as shown in Figure 13-3. The
input to this divider comes from the SPI baud rate prescaler (see Figure 13-4). The output of this
divider is the SPI bit rate clock for master mode.
Table 13-2. SPI Baud Rate Prescaler Divisor
SPPR2:SPPR1:SPPR0 Prescaler Divisor
0:0:0 1
0:0:1 2
0:1:0 3
0:1:1 4
1:0:0 5
1:0:1 6
1:1:0 7
1:1:1 8
Table 13-3. SPI Baud Rate Divisor
SPR2:SPR1:SPR0 Rate Divisor
0:0:0 2
0:0:1 4
0:1:0 8
0:1:1 16
1:0:0 32
1:0:1 64
1:1:0 128
1:1:1 256
Serial Peripheral Interface (SPI) Module
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
176 Freescale Semiconductor
13.4.4 SPI Status Register (SPI1S)
This register has three read-only status bits. Bits 6, 3, 2, 1, and 0 are not implemented and always read 0s.
Writes have no meaning or effect.
Figure 13-10. SPI Status Register (SPI1S)
SPRF — SPI Read Buffer Full Flag
SPRF is set at the completion of an SPI transfer to indicate that received data may be read from the SPI
data register (SPI1D). SPRF is cleared by reading SPRF while it is set, then reading the SPI data
register.
1 = Data available in the receive data buffer.
0 = No data available in the receive data buffer.
SPTEF — SPI Transmit Buffer Empty Flag
This bit is set when there is room in the transmit data buffer. It is cleared by reading SPI1S with SPTEF
set, followed by writing a data value to the transmit buffer at SPI1D. SPI1S must be read with
SPTEF = 1 before writing data to SPI1D or the SPI1D write will be ignored. SPTEF generates an
SPTEF CPU interrupt request if the SPTIE bit in the SPI1C1 is also set. SPTEF is automatically set
when a data byte transfers from the transmit buffer into the transmit shift register. For an idle SPI (no
data in the transmit buffer or the shift register and no transfer in progress), data written to SPI1D is
transferred to the shifter almost immediately so SPTEF is set within two bus cycles allowing a second
8-bit data value to be queued into the transmit buffer. After completion of the transfer of the value in
the shift register, the queued value from the transmit buffer will automatically move to the shifter and
SPTEF will be set to indicate there is room for new data in the transmit buffer. If no new data is waiting
in the transmit buffer, SPTEF simply remains set and no data moves from the buffer to the shifter.
1 = SPI transmit buffer empty.
0 = SPI transmit buffer not empty.
MODF — Master Mode Fault Flag
MODF is set if the SPI is configured as a master and the slave select input goes low, indicating some
other SPI device is also configured as a master. The SS1 pin acts as a mode fault error input only when
MSTR = 1, MODFEN = 1, and SSOE = 0; otherwise, MODF will never be set. MODF is cleared by
reading MODF while it is 1, then writing to SPI control register 1 (SPI1C1).
1 = Mode fault error detected.
0 = No mode fault error.
Bit 7 654321Bit 0
Read: <st-blue>
SPRF 0<st-blue>
SPTEF
<st-blue>
MODF 0000
Write:
Reset: 00100000
= Unimplemented or Reserved
Serial Peripheral Interface (SPI) Module
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 177
13.4.5 SPI Data Register (SPI1D)
Figure 13-11. SPI Data Register (SPI1D)
Reads of this register return the data read from the receive data buffer. Writes to this register write data
to the transmit data buffer. When the SPI is configured as a master, writing data to the transmit data
buffer initiates an SPI transfer.
Data should not be written to the transmit data buffer unless the SPI transmit buffer empty flag
(SPTEF) is set, indicating there is room in the transmit buffer to queue a new transmit byte.
Data may be read from SPI1D any time after SPRF is set and before another transfer is finished. Failure
to read the data out of the receive data buffer before a new transfer ends causes a receive overrun
condition and the data from the new transfer is lost.
Bit 7 654321Bit 0
Read:
Bit 7 654321Bit 0
Write:
Reset: 00000000
Serial Peripheral Interface (SPI) Module
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
178 Freescale Semiconductor
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 179
Chapter 14
Analog Comparator (S08ACMPV1)
The 32-, 44-, and 46-pin packages of the MC9S08RCxx, MC9S08RExx, and MC9S08RGxx devices
include an analog comparator. This comparator has two inputs or can optionally use an internal bandgap
reference. The comparator inputs are shared with PTD4 and PTD5 port I/O pins.
Figure 14-1. MC9S08RC/RD/RE/RG Block Diagram Highlighting ACMP Block and Pins
PTD3
PTD4/ACMP1–
PTD5/ACMP1+
PTD6/TPM1CH0
PTC1/KBI2P1
PTC0/KBI2P0
VSS
VDD
PTB3
PTB2
PTA7/KBI1P7–
PTB0/TxD1
PTB1/RxD1
PTD2/IRQ
PTD1/RESET
PTD0/BKGD/MS
PTC7/SS1
PTC6/SPSCK1
PTC5/MISO1
PTC4/MOSI1
PTC3/KBI2P3
PTC2/KBI2P2
PORT A
PORT C
PORT D
PORT B
8-BIT KEYBOARD
INTERRUPT MODULE (KBI1)
SERIAL PERIPHERAL
INTERFACE MODULE (SPI1)
USER FLASH
USER RAM
(RC/RD/RE/RG32/60 = 2048 BYTES)
DEBUG
MODULE (DBG)
(RC/RD/RE/RG60 = 63,364 BYTES)
HCS08 CORE
CPU
BDC
INT
BKP
NOTES
NOTES 1, 5
2-CHANNEL TIMER/PWM
MODULE (TPM1)
PTE7–
PORT E
PTB5
PTB4
PTE6
PTB7/TPM1CH1
MODULE (ACMP1)
HCS08 SYSTEM CONTROL
RESETS AND INTERRUPTS
MODES OF OPERATION
POWER MANAGEMENT
VOLTAGE
REGULATOR
RTI
ANALOG COMPARATOR
COP
IRQ LVD
INTERNAL BUS
LOW-POWER OSCILLATOR
INTERFACE MODULE (SCI1)
SERIAL COMMUNICATIONS
7
PTA1/KBI1P1
8
PTE0
NOTE 1
NOTES1, 2
NOTE 1
(RC/RD/RE/RG32 = 32,768 BYTES)
(RC/RD/RE8/16 = 1024 BYTES)
(RC/RD/RE16 = 16,384 BYTES)
XTAL
EXTAL
CARRIER MODULATOR
TIMER MODULE (CMT)
1, 3, 4
4-BIT KEYBOARD
INTERRUPT MODULE (KBI2)
IRO NOTE 5
PTA0/KBI1P0
(RC/RD/RE8 = 8192 BYTES)
NOTES:
19.Port pins are software configurable with pullup device if input port
20.PTA0 does not have a clamp diode to VDD. PTA0 should not be driven above VDD. Also, PTA0 does not pullup to VDD when internal
pullup is enabled.
21.IRQ pin contains software configurable pullup/pulldown device if IRQ enabled (IRQPE = 1)
22.The RESET pin contains integrated pullup device enabled if reset enabled (RSTPE = 1)
23.High current drive
24.Pins PTA[7:4] contain both pullup and pulldown devices. Pulldown enabled when KBI is enabled (KBIPEn = 1) and rising edge is
selected (KBEDGn = 1).
Analog Comparator (ACMP) Block Description
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
180 Freescale Semiconductor
14.1 Features
The ACMP has the following features:
• Full rail-to-rail supply operation.
• Less than 40 mV of input offset.
• Selectable interrupt on rising edge, falling edge, or either rising or falling edge of comparator
output.
• Option to compare to fixed internal bandgap reference voltage.
14.2 Block Diagram
The block diagram for the analog comparator module is shown below.
Figure 14-2. Analog Comparator Module Block Diagram
14.3 Pin Description
The ACMP has two analog input pins: ACMP1– and ACMP1+. Each of these pins can accept an input
voltage that varies across the full operating voltage range of the MCU. When the ACMP1+ is configured
to use the internal bandgap reference, ACMP1+ is available to be as general-purpose I/O. As shown in the
block diagram, the ACMP1+ pin is connected to the comparator non-inverting input if ACBGS is equal to
logic 0, and the ACMP1– pin is connected to the inverting input of the comparator.
+
–
INTERRUPT
CONTROL
AC IRQ
INTERNAL
REFERENCE
ACBGS
INTERNAL BUS
STATUS & CONTROL
REGISTER
ACMOD1
ACMOD0
SET ACF
ACPE
ACF
ACIE
ACMP1+
ACMP1–
Analog Comparator (ACMP) Block Description
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 181
14.4 Functional Description
The analog comparator can be used to compare two analog input voltages applied to ACMP1– and
ACMP1+; or it can be used to compare an analog input voltage applied to ACMP1– with an internal
bandgap reference voltage. The ACBGS bit is used to select the mode of operation. The comparator output
is high when the non-inverting input is greater than the inverting input, and is low when the non-inverting
input is less than the inverting input. The ACMOD0 and ACMOD1 bits are used to select the condition
that will cause the ACF bit to be set. The ACF bit can be set on a rising edge of the comparator output, a
falling edge of the comparator output, or either a rising or a falling edge. The comparator output can be
read directly through the ACO bit.
14.4.1 Interrupts
The ACMP module is capable of generating an interrupt on a compare event. The interrupt request is
asserted when both the ACIE bit and the ACF bit are set. The interrupt is deasserted by clearing either the
ACIE bit or the ACF bit. The ACIE bit is cleared by writing a 0 and the ACF bit is cleared by writing a 1.
14.4.2 Wait Mode Operation
During wait mode the ACMP, if enabled, will continue to operate normally. Also, if enabled, the interrupt
can wake up the MCU.
14.4.3 Stop Mode Operation
During stop mode, clocks to the ACMP module are halted. The ACMP comparator circuit will enter a low
power state. No compare operation will occur while in stop mode.
In stop1 and stop2 modes, the ACMP module will be in its reset state when the MCU recovers from the
stop condition and must be re-initialized.
In stop3 mode, control and status register information is maintained and upon recovery normal ACMP
function is available to the user.
14.4.4 Background Mode Operation
When the microcontroller is in active background mode, the ACMP will continue to operate normally.
Analog Comparator (ACMP) Block Description
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
182 Freescale Semiconductor
14.5 ACMP Status and Control Register (ACMP1SC)
76543210
R
ACME ACBGS ACF ACIE
ACO 0
ACMOD1 ACMOD0
W
Reset 00000000
= Unimplemented or Reserved
Figure 14-3. ACMP Status and Control Register (ACMP1SC)
Table 14-1. ACMP1SC Field Descriptions
Field Description
7
ACME
Analog Comparator Module Enable — The ACME bit enables the analog comparator module. When the
module is not enabled, it remains in a low-power state.
0 Analog comparator disabled
1 Analog comparator enabled
6
ACBGS
Analog Comparator Bandgap Select — The ACBGS bit is used to select the internal bandgap as the
comparator reference.
0 External pin ACMP1+ selected as comparator non-inverting input
1 Internal bandgap reference selected as comparator non-inverting input
5
ACF
Analog Comparator Flag — The ACF bit is set when a compare event occurs. Compare events are defined by
the ACMOD0 and ACMOD1 bits. The ACF bit is cleared by writing a 1 to the bit.
0 Compare event has not occurred.
1 Compare event has occurred.
4
ACIE
Analog Comparator Interrupt Enable — The ACIE bit enables the interrupt from the ACMP. When this bit is
set, an interrupt will be asserted when the ACF bit is set.
0 Interrupt disabled
1 Interrupt enabled
3
ACO
Analog Comparator Output — Reading the ACO bit will return the current value of the analog comparator
output. The register bit is reset to 0 and will read as 0 when the analog comparator module is disabled (ACME =
0).
1:0
ACMOD[1:0]
Analog Comparator Modes — The ACMOD1 and ACMOD0 bits select the flag setting mode that controls the
type of compare event that sets the ACF bit.
00 Comparator output falling edge
01 Comparator output rising edge
10 Comparator output falling edge
11 Comparator output either rising or falling edge
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 183
Chapter 15
Development Support
15.1 Introduction
15.1.1 Features
Features of the background debug controller (BDC) include:
• Single pin for mode selection and background communications
• BDC registers are not located in the memory map
• SYNC command to determine target communications rate
• Non-intrusive commands for memory access
• Active background mode commands for CPU register access
• GO and TRACE1 commands
• BACKGROUND command can wake CPU from stop or wait modes
• One hardware address breakpoint built into BDC
• Oscillator runs in stop mode, if BDC enabled
• COP watchdog disabled while in active background mode
Features of the debug module (DBG) include:
• Two trigger comparators:
— Two address + read/write (R/W) or
— One full address + data + R/W
• Flexible 8-word by 16-bit FIFO (first-in, first-out) buffer for capture information:
— Change-of-flow addresses or
— Event-only data
• Two types of breakpoints:
— Tag breakpoints for instruction opcodes
— Force breakpoints for any address access
• Nine trigger modes:
— A-only
— A OR B
— A then B
— A AND B data (full mode)
— A AND NOT B data (full mode)
— Event-only B (store data)
— A then event-only B (store data)
Development Support
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
184 Freescale Semiconductor
— Inside range (A ≤ address ≤ B)
— Outside range (address < A or address > B)
15.2 Background Debug Controller (BDC)
All MCUs in the HCS08 Family contain a single-wire background debug interface that supports in-circuit
programming of on-chip nonvolatile memory and sophisticated non-intrusive debug capabilities. Unlike
debug interfaces on earlier 8-bit MCUs, this system does not interfere with normal application resources.
It does not use any user memory or locations in the memory map and does not share any on-chip
peripherals.
BDC commands are divided into two groups:
• Active background mode commands require that the target MCU is in active background mode (the
user program is not running). Active background mode commands allow the CPU registers to be
read or written, and allow the user to trace one user instruction at a time, or GO to the user program
from active background mode.
• Non-intrusive commands can be executed at any time even while the user’s program is running.
Non-intrusive commands allow a user to read or write MCU memory locations or access status and
control registers within the background debug controller.
Typically, a relatively simple interface pod is used to translate commands from a host computer into
commands for the custom serial interface to the single-wire background debug system. Depending on the
development tool vendor, this interface pod may use a standard RS-232 serial port, a parallel printer port,
or some other type of communications such as a universal serial bus (USB) to communicate between the
host PC and the pod. The pod typically connects to the target system with ground, the BKGD pin, RESET,
and sometimes VDD. An open-drain connection to reset allows the host to force a target system reset,
which is useful to regain control of a lost target system or to control startup of a target system before the
on-chip nonvolatile memory has been programmed. Sometimes VDD can be used to allow the pod to use
power from the target system to avoid the need for a separate power supply. However, if the pod is powered
separately, it can be connected to a running target system without forcing a target system reset or otherwise
disturbing the running application program.
Figure 15-1. BDM Tool Connector
15.2.1 BKGD Pin Description
BKGD is the single-wire background debug interface pin. The primary function of this pin is for
bidirectional serial communication of active background mode commands and data. During reset, this pin
is used to select between starting in active background mode or starting the user’s application program.
This pin is also used to request a timed sync response pulse to allow a host development tool to determine
the correct clock frequency for background debug serial communications.
2
4
6NO CONNECT 5
NO CONNECT 3
1
RESET
BKGD GND
VDD
Development Support
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 185
BDC serial communications use a custom serial protocol first introduced on the M68HC12 Family of
microcontrollers. This protocol assumes the host knows the communication clock rate that is determined
by the target BDC clock rate. All communication is initiated and controlled by the host that drives a
high-to-low edge to signal the beginning of each bit time. Commands and data are sent most significant bit
first (MSB first). For a detailed description of the communications protocol, refer to Section 15.2.2,
“Communication Details.”
If a host is attempting to communicate with a target MCU that has an unknown BDC clock rate, a SYNC
command may be sent to the target MCU to request a timed sync response signal from which the host can
determine the correct communication speed.
BKGD is a pseudo-open-drain pin and there is an on-chip pullup so no external pullup resistor is required.
Unlike typical open-drain pins, the external RC time constant on this pin, which is influenced by external
capacitance, plays almost no role in signal rise time. The custom protocol provides for brief, actively
driven speedup pulses to force rapid rise times on this pin without risking harmful drive level conflicts.
Refer to Section 15.2.2, “Communication Details,” for more detail.
When no debugger pod is connected to the 6-pin BDM interface connector, the internal pullup on BKGD
chooses normal operating mode. When a development system is connected, it can pull both BKGD and
RESET low, release RESET to select active background mode rather than normal operating mode, then
release BKGD. It is not necessary to reset the target MCU to communicate with it through the background
debug interface.
15.2.2 Communication Details
The BDC serial interface requires the external controller to generate a falling edge on the BKGD pin to
indicate the start of each bit time. The external controller provides this falling edge whether data is
transmitted or received.
BKGD is a pseudo-open-drain pin that can be driven either by an external controller or by the MCU. Data
is transferred MSB first at 16 BDC clock cycles per bit (nominal speed). The interface times out if
512 BDC clock cycles occur between falling edges from the host. Any BDC command that was in progress
when this timeout occurs is aborted without affecting the memory or operating mode of the target MCU
system.
The custom serial protocol requires the debug pod to know the target BDC communication clock speed.
The clock switch (CLKSW) control bit in the BDC status and control register allows the user to select the
BDC clock source. The BDC clock source can either be the bus or the alternate BDC clock source.
The BKGD pin can receive a high or low level or transmit a high or low level. The following diagrams
show timing for each of these cases. Interface timing is synchronous to clocks in the target BDC, but
asynchronous to the external host. The internal BDC clock signal is shown for reference in counting cycles.
Development Support
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
186 Freescale Semiconductor
Figure 15-2 shows an external host transmitting a logic 1 or 0 to the BKGD pin of a target HCS08 MCU.
The host is asynchronous to the target so there is a 0-to-1 cycle delay from the host-generated falling edge
to where the target perceives the beginning of the bit time. Ten target BDC clock cycles later, the target
senses the bit level on the BKGD pin. Typically, the host actively drives the pseudo-open-drain BKGD pin
during host-to-target transmissions to speed up rising edges. Because the target does not drive the BKGD
pin during the host-to-target transmission period, there is no need to treat the line as an open-drain signal
during this period.
Figure 15-2. BDC Host-to-Target Serial Bit Timing
EARLIEST START
TARGET SENSES BIT LEVEL
10 CYCLES
SYNCHRONIZATION
UNCERTAINTY
BDC CLOCK
(TARGET MCU)
HOST
TRANSMIT 1
HOST
TRANSMIT 0
PERCEIVED START
OF BIT TIME
OF NEXT BIT
Development Support
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 187
Figure 15-3 shows the host receiving a logic 1 from the target HCS08 MCU. Because the host is
asynchronous to the target MCU, there is a 0-to-1 cycle delay from the host-generated falling edge on
BKGD to the perceived start of the bit time in the target MCU. The host holds the BKGD pin low long
enough for the target to recognize it (at least two target BDC cycles). The host must release the low drive
before the target MCU drives a brief active-high speedup pulse seven cycles after the perceived start of the
bit time. The host should sample the bit level about 10 cycles after it started the bit time.
Figure 15-3. BDC Target-to-Host Serial Bit Timing (Logic 1)
HOST SAMPLES BKGD PIN
10 CYCLES
BDC CLOCK
(TARGET MCU)
HOST DRIVE
TO BKGD PIN
TARGET MCU
SPEEDUP PULSE
PERCEIVED START
OF BIT TIME
HIGH-IMPEDANCE
HIGH-IMPEDANCE HIGH-IMPEDANCE
BKGD PIN
R-C RISE
10 CYCLES
EARLIEST START
OF NEXT BIT
Development Support
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
188 Freescale Semiconductor
Figure 15-4 shows the host receiving a logic 0 from the target HCS08 MCU. Because the host is
asynchronous to the target MCU, there is a 0-to-1 cycle delay from the host-generated falling edge on
BKGD to the start of the bit time as perceived by the target MCU. The host initiates the bit time but the
target HCS08 finishes it. Because the target wants the host to receive a logic 0, it drives the BKGD pin low
for 13 BDC clock cycles, then briefly drives it high to speed up the rising edge. The host samples the bit
level about 10 cycles after starting the bit time.
Figure 15-4. BDM Target-to-Host Serial Bit Timing (Logic 0)
10 CYCLES
BDC CLOCK
(TARGET MCU)
HOST DRIVE
TO BKGD PIN
TARGET MCU
DRIVE AND
PERCEIVED START
OF BIT TIME
HIGH-IMPEDANCE
BKGD PIN
10 CYCLES
SPEED-UP PULSE
SPEEDUP
PULSE
EARLIEST START
OF NEXT BIT
HOST SAMPLES BKGD PIN
Development Support
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 189
15.2.3 BDC Commands
BDC commands are sent serially from a host computer to the BKGD pin of the target HCS08 MCU. All
commands and data are sent MSB-first using a custom BDC communications protocol. Active background
mode commands require that the target MCU is currently in the active background mode while
non-intrusive commands may be issued at any time whether the target MCU is in active background mode
or running a user application program.
Table 15-1 shows all HCS08 BDC commands, a shorthand description of their coding structure, and the
meaning of each command.
Coding Structure Nomenclature
This nomenclature is used in Table 15-1 to describe the coding structure of the BDC commands.
Commands begin with an 8-bit hexadecimal command code in the host-to-target
direction (most significant bit first)
/ = separates parts of the command
d = delay 16 target BDC clock cycles
AAAA = a 16-bit address in the host-to-target direction
RD = 8 bits of read data in the target-to-host direction
WD = 8 bits of write data in the host-to-target direction
RD16 = 16 bits of read data in the target-to-host direction
WD16 = 16 bits of write data in the host-to-target direction
SS = the contents of BDCSCR in the target-to-host direction (STATUS)
CC = 8 bits of write data for BDCSCR in the host-to-target direction (CONTROL)
RBKP = 16 bits of read data in the target-to-host direction (from BDCBKPT breakpoint
register)
WBKP = 16 bits of write data in the host-to-target direction (for BDCBKPT breakpoint register)
Development Support
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
190 Freescale Semiconductor
Table 15-1. BDC Command Summary
Command
Mnemonic
Active BDM/
Non-intrusive
Coding
Structure Description
SYNC Non-intrusive n/a1
1The SYNC command is a special operation that does not have a command code.
Request a timed reference pulse to determine
target BDC communication speed
ACK_ENABLE Non-intrusive D5/d Enable acknowledge protocol. Refer to
Freescale document order no. HCS08RMv1/D.
ACK_DISABLE Non-intrusive D6/d Disable acknowledge protocol. Refer to
Freescale document order no. HCS08RMv1/D.
BACKGROUND Non-intrusive 90/d Enter active background mode if enabled
(ignore if ENBDM bit equals 0)
READ_STATUS Non-intrusive E4/SS Read BDC status from BDCSCR
WRITE_CONTROL Non-intrusive C4/CC Write BDC controls in BDCSCR
READ_BYTE Non-intrusive E0/AAAA/d/RD Read a byte from target memory
READ_BYTE_WS Non-intrusive E1/AAAA/d/SS/RD Read a byte and report status
READ_LAST Non-intrusive E8/SS/RD Re-read byte from address just read and
report status
WRITE_BYTE Non-intrusive C0/AAAA/WD/d Write a byte to target memory
WRITE_BYTE_WS Non-intrusive C1/AAAA/WD/d/SS Write a byte and report status
READ_BKPT Non-intrusive E2/RBKP Read BDCBKPT breakpoint register
WRITE_BKPT Non-intrusive C2/WBKP Write BDCBKPT breakpoint register
GO Active BDM 08/d Go to execute the user application program
starting at the address currently in the PC
TRACE1 Active BDM 10/d Trace 1 user instruction at the address in the
PC, then return to active background mode
TAGGO Active BDM 18/d Same as GO but enable external tagging
(HCS08 devices have no external tagging pin)
READ_A Active BDM 68/d/RD Read accumulator (A)
READ_CCR Active BDM 69/d/RD Read condition code register (CCR)
READ_PC Active BDM 6B/d/RD16 Read program counter (PC)
READ_HX Active BDM 6C/d/RD16 Read H and X register pair (H:X)
READ_SP Active BDM 6F/d/RD16 Read stack pointer (SP)
READ_NEXT Active BDM 70/d/RD Increment H:X by one then read memory byte
located at H:X
READ_NEXT_WS Active BDM 71/d/SS/RD Increment H:X by one then read memory byte
located at H:X. Report status and data.
WRITE_A Active BDM 48/WD/d Write accumulator (A)
WRITE_CCR Active BDM 49/WD/d Write condition code register (CCR)
WRITE_PC Active BDM 4B/WD16/d Write program counter (PC)
WRITE_HX Active BDM 4C/WD16/d Write H and X register pair (H:X)
WRITE_SP Active BDM 4F/WD16/d Write stack pointer (SP)
WRITE_NEXT Active BDM 50/WD/d Increment H:X by one, then write memory byte
located at H:X
WRITE_NEXT_WS Active BDM 51/WD/d/SS Increment H:X by one, then write memory byte
located at H:X. Also report status.
Development Support
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 191
The SYNC command is unlike other BDC commands because the host does not necessarily know the
correct communications speed to use for BDC communications until after it has analyzed the response to
the SYNC command.
To issue a SYNC command, the host:
• Drives the BKGD pin low for at least 128 cycles of the slowest possible BDC clock (The slowest
clock is normally the reference oscillator/64 or the self-clocked rate/64.)
• Drives BKGD high for a brief speedup pulse to get a fast rise time (This speedup pulse is typically
one cycle of the fastest clock in the system.)
• Removes all drive to the BKGD pin so it reverts to high impedance
• Monitors the BKGD pin for the sync response pulse
The target, upon detecting the SYNC request from the host (which is a much longer low time than would
ever occur during normal BDC communications):
• Waits for BKGD to return to a logic high
• Delays 16 cycles to allow the host to stop driving the high speedup pulse
• Drives BKGD low for 128 BDC clock cycles
• Drives a 1-cycle high speedup pulse to force a fast rise time on BKGD
• Removes all drive to the BKGD pin so it reverts to high impedance
The host measures the low time of this 128-cycle sync response pulse and determines the correct speed for
subsequent BDC communications. Typically, the host can determine the correct communication speed
within a few percent of the actual target speed and the communication protocol can easily tolerate speed
errors of several percent.
15.2.4 BDC Hardware Breakpoint
The BDC includes one relatively simple hardware breakpoint that compares the CPU address bus to a
16-bit match value in the BDCBKPT register. This breakpoint can generate a forced breakpoint or a tagged
breakpoint. A forced breakpoint causes the CPU to enter active background mode at the first instruction
boundary following any access to the breakpoint address. The tagged breakpoint causes the instruction
opcode at the breakpoint address to be tagged so that the CPU will enter active background mode rather
than executing that instruction if and when it reaches the end of the instruction queue. This implies that
tagged breakpoints can only be placed at the address of an instruction opcode while forced breakpoints can
be set at any address.
The breakpoint enable (BKPTEN) control bit in the BDC status and control register (BDCSCR) is used to
enable the breakpoint logic (BKPTEN = 1). When BKPTEN = 0, its default value after reset, the
breakpoint logic is disabled and no BDC breakpoints are requested regardless of the values in other BDC
breakpoint registers and control bits. The force/tag select (FTS) control bit in BDCSCR is used to select
forced (FTS = 1) or tagged (FTS = 0) type breakpoints.
The on-chip debug module (DBG) includes circuitry for two additional hardware breakpoints that are more
flexible than the simple breakpoint in the BDC module.
Development Support
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
192 Freescale Semiconductor
15.3 On-Chip Debug System (DBG)
Because HCS08 devices do not have external address and data buses, the most important functions of an
in-circuit emulator have been built onto the chip with the MCU. The debug system consists of an 8-stage
FIFO that can store address or data bus information, and a flexible trigger system to decide when to capture
bus information and what information to capture. The system relies on the single-wire background debug
system to access debug control registers and to read results out of the eight stage FIFO.
The debug module includes control and status registers that are accessible in the user’s memory map.
These registers are located in the high register space to avoid using valuable direct page memory space.
Most of the debug module’s functions are used during development, and user programs rarely access any
of the control and status registers for the debug module. The one exception is that the debug system can
provide the means to implement a form of ROM patching. This topic is discussed in greater detail in
Section 15.3.6, “Hardware Breakpoints.”
15.3.1 Comparators A and B
Two 16-bit comparators (A and B) can optionally be qualified with the R/W signal and an opcode tracking
circuit. Separate control bits allow you to ignore R/W for each comparator. The opcode tracking circuitry
optionally allows you to specify that a trigger will occur only if the opcode at the specified address is
actually executed as opposed to only being read from memory into the instruction queue. The comparators
are also capable of magnitude comparisons to support the inside range and outside range trigger modes.
Comparators are disabled temporarily during all BDC accesses.
The A comparator is always associated with the 16-bit CPU address. The B comparator compares to the
CPU address or the 8-bit CPU data bus, depending on the trigger mode selected. Because the CPU data
bus is separated into a read data bus and a write data bus, the RWAEN and RWA control bits have an
additional purpose, in full address plus data comparisons they are used to decide which of these buses to
use in the comparator B data bus comparisons. If RWAEN = 1 (enabled) and RWA = 0 (write), the CPU’s
write data bus is used. Otherwise, the CPU’s read data bus is used.
The currently selected trigger mode determines what the debugger logic does when a comparator detects
a qualified match condition. A match can cause:
• Generation of a breakpoint to the CPU
• Storage of data bus values into the FIFO
• Starting to store change-of-flow addresses into the FIFO (begin type trace)
• Stopping the storage of change-of-flow addresses into the FIFO (end type trace)
15.3.2 Bus Capture Information and FIFO Operation
The usual way to use the FIFO is to setup the trigger mode and other control options, then arm the
debugger. When the FIFO has filled or the debugger has stopped storing data into the FIFO, you would
read the information out of it in the order it was stored into the FIFO. Status bits indicate the number of
words of valid information that are in the FIFO as data is stored into it. If a trace run is manually halted by
writing 0 to ARM before the FIFO is full (CNT = 1:0:0:0), the information is shifted by one position and
Development Support
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 193
the host must perform ((8 – CNT) – 1) dummy reads of the FIFO to advance it to the first significant entry
in the FIFO.
In most trigger modes, the information stored in the FIFO consists of 16-bit change-of-flow addresses. In
these cases, read DBGFH then DBGFL to get one coherent word of information out of the FIFO. Reading
DBGFL (the low-order byte of the FIFO data port) causes the FIFO to shift so the next word of information
is available at the FIFO data port. In the event-only trigger modes (see Section 15.3.5, “Trigger Modes”),
8-bit data information is stored into the FIFO. In these cases, the high-order half of the FIFO (DBGFH) is
not used and data is read out of the FIFO by simply reading DBGFL. Each time DBGFL is read, the FIFO
is shifted so the next data value is available through the FIFO data port at DBGFL.
In trigger modes where the FIFO is storing change-of-flow addresses, there is a delay between CPU
addresses and the input side of the FIFO. Because of this delay, if the trigger event itself is a change-of-flow
address or a change-of-flow address appears during the next two bus cycles after a trigger event starts the
FIFO, it will not be saved into the FIFO. In the case of an end-trace, if the trigger event is a change-of-flow,
it will be saved as the last change-of-flow entry for that debug run.
The FIFO can also be used to generate a profile of executed instruction addresses when the debugger is not
armed. When ARM = 0, reading DBGFL causes the address of the most-recently fetched opcode to be
saved in the FIFO. To use the profiling feature, a host debugger would read addresses out of the FIFO by
reading DBGFH then DBGFL at regular periodic intervals. The first eight values would be discarded
because they correspond to the eight DBGFL reads needed to initially fill the FIFO. Additional periodic
reads of DBGFH and DBGFL return delayed information about executed instructions so the host debugger
can develop a profile of executed instruction addresses.
15.3.3 Change-of-Flow Information
To minimize the amount of information stored in the FIFO, only information related to instructions that
cause a change to the normal sequential execution of instructions is stored. With knowledge of the source
and object code program stored in the target system, an external debugger system can reconstruct the path
of execution through many instructions from the change-of-flow information stored in the FIFO.
For conditional branch instructions where the branch is taken (branch condition was true), the source
address is stored (the address of the conditional branch opcode). Because BRA and BRN instructions are
not conditional, these events do not cause change-of-flow information to be stored in the FIFO.
Indirect JMP and JSR instructions use the current contents of the H:X index register pair to determine the
destination address, so the debug system stores the run-time destination address for any indirect JMP or
JSR. For interrupts, RTI, or RTS, the destination address is stored in the FIFO as change-of-flow
information.
15.3.4 Tag vs. Force Breakpoints and Triggers
Tagging is a term that refers to identifying an instruction opcode as it is fetched into the instruction queue,
but not taking any other action until and unless that instruction is actually executed by the CPU. This
distinction is important because any change-of-flow from a jump, branch, subroutine call, or interrupt
causes some instructions that have been fetched into the instruction queue to be thrown away without being
executed.
Development Support
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
194 Freescale Semiconductor
A force-type breakpoint waits for the current instruction to finish and then acts upon the breakpoint
request. The usual action in response to a breakpoint is to go to active background mode rather than
continuing to the next instruction in the user application program.
The tag vs. force terminology is used in two contexts within the debug module. The first context refers to
breakpoint requests from the debug module to the CPU. The second refers to match signals from the
comparators to the debugger control logic. When a tag-type break request is sent to the CPU, a signal is
entered into the instruction queue along with the opcode so that if/when this opcode ever executes, the CPU
will effectively replace the tagged opcode with a BGND opcode so the CPU goes to active background
mode rather than executing the tagged instruction. When the TRGSEL control bit in the DBGT register is
set to select tag-type operation, the output from comparator A or B is qualified by a block of logic in the
debug module that tracks opcodes and only produces a trigger to the debugger if the opcode at the compare
address is actually executed. There is separate opcode tracking logic for each comparator so more than one
compare event can be tracked through the instruction queue at a time.
15.3.5 Trigger Modes
The trigger mode controls the overall behavior of a debug run. The 4-bit TRG field in the DBGT register
selects one of nine trigger modes. When TRGSEL = 1 in the DBGT register, the output of the comparator
must propagate through an opcode tracking circuit before triggering FIFO actions. The BEGIN bit in
DBGT chooses whether the FIFO begins storing data when the qualified trigger is detected (begin trace),
or the FIFO stores data in a circular fashion from the time it is armed until the qualified trigger is detected
(end trigger).
A debug run is started by writing a 1 to the ARM bit in the DBGC register, which sets the ARMF flag and
clears the AF and BF flags and the CNT bits in DBGS. A begin-trace debug run ends when the FIFO gets
full. An end-trace run ends when the selected trigger event occurs. Any debug run can be stopped manually
by writing a 0 to ARM or DBGEN in DBGC.
In all trigger modes except event-only modes, the FIFO stores change-of-flow addresses. In event-only
trigger modes, the FIFO stores data in the low-order eight bits of the FIFO.
The BEGIN control bit is ignored in event-only trigger modes and all such debug runs are begin type
traces. When TRGSEL = 1 to select opcode fetch triggers, it is not necessary to use R/W in comparisons
because opcode tags would only apply to opcode fetches that are always read cycles. It would also be
unusual to specify TRGSEL = 1 while using a full mode trigger because the opcode value is normally
known at a particular address.
The following trigger mode descriptions only state the primary comparator conditions that lead to a trigger.
Either comparator can usually be further qualified with R/W by setting RWAEN (RWBEN) and the
corresponding RWA (RWB) value to be matched against R/W. The signal from the comparator with
optional R/W qualification is used to request a CPU breakpoint if BRKEN = 1 and TAG determines
whether the CPU request will be a tag request or a force request.
Development Support
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 195
A-Only — Trigger when the address matches the value in comparator A
A OR B — Trigger when the address matches either the value in comparator A or the value in
comparator B
A Then B — Trigger when the address matches the value in comparator B but only after the address for
another cycle matched the value in comparator A. There can be any number of cycles after the A match
and before the B match.
A AND B Data (Full Mode) — This is called a full mode because address, data, and R/W (optionally)
must match within the same bus cycle to cause a trigger event. Comparator A checks address, the low byte
of comparator B checks data, and R/W is checked against RWA if RWAEN = 1. The high-order half of
comparator B is not used.
In full trigger modes it is not useful to specify a tag-type CPU breakpoint (BRKEN = TAG = 1), but if you
do, the comparator B data match is ignored for the purpose of issuing the tag request to the CPU and the
CPU breakpoint is issued when the comparator A address matches.
A AND NOT B Data (Full Mode) — Address must match comparator A, data must not match the low
half of comparator B, and R/W must match RWA if RWAEN = 1. All three conditions must be met within
the same bus cycle to cause a trigger.
In full trigger modes it is not useful to specify a tag-type CPU breakpoint (BRKEN = TAG = 1), but if you
do, the comparator B data match is ignored for the purpose of issuing the tag request to the CPU and the
CPU breakpoint is issued when the comparator A address matches.
Event-Only B (Store Data) — Trigger events occur each time the address matches the value in
comparator B. Trigger events cause the data to be captured into the FIFO. The debug run ends when the
FIFO becomes full.
A Then Event-Only B (Store Data) — After the address has matched the value in comparator A, a trigger
event occurs each time the address matches the value in comparator B. Trigger events cause the data to be
captured into the FIFO. The debug run ends when the FIFO becomes full.
Inside Range (A ≤Address ≤B) — A trigger occurs when the address is greater than or equal to the value
in comparator A and less than or equal to the value in comparator B at the same time.
Outside Range (Address < A or Address > B) — A trigger occurs when the address is either less than
the value in comparator A or greater than the value in comparator B.
Development Support
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
196 Freescale Semiconductor
15.3.6 Hardware Breakpoints
The BRKEN control bit in the DBGC register may be set to 1 to allow any of the trigger conditions
described in Section 15.3.5, “Trigger Modes,” to be used to generate a hardware breakpoint request to the
CPU. TAG in DBGC controls whether the breakpoint request will be treated as a tag-type breakpoint or a
force-type breakpoint. A tag breakpoint causes the current opcode to be marked as it enters the instruction
queue. If a tagged opcode reaches the end of the pipe, the CPU executes a BGND instruction to go to active
background mode rather than executing the tagged opcode. A force-type breakpoint causes the CPU to
finish the current instruction and then go to active background mode.
If the background mode has not been enabled (ENBDM = 1) by a serial WRITE_CONTROL command
through the BKGD pin, the CPU will execute an SWI instruction instead of going to active background
mode.
15.4 Register Definition
This section contains the descriptions of the BDC and DBG registers and control bits.
Refer to the high-page register summary in the device overview chapter of this data sheet for the absolute
address assignments for all DBG registers. This section refers to registers and control bits only by their
names. A Freescale-provided equate or header file is used to translate these names into the appropriate
absolute addresses.
15.4.1 BDC Registers and Control Bits
The BDC has two registers:
• The BDC status and control register (BDCSCR) is an 8-bit register containing control and status
bits for the background debug controller.
• The BDC breakpoint match register (BDCBKPT) holds a 16-bit breakpoint match address.
These registers are accessed with dedicated serial BDC commands and are not located in the memory
space of the target MCU (so they do not have addresses and cannot be accessed by user programs).
Some of the bits in the BDCSCR have write limitations; otherwise, these registers may be read or written
at any time. For example, the ENBDM control bit may not be written while the MCU is in active
background mode. (This prevents the ambiguous condition of the control bit forbidding active background
mode while the MCU is already in active background mode.) Also, the four status bits (BDMACT, WS,
WSF, and DVF) are read-only status indicators and can never be written by the WRITE_CONTROL serial
BDC command. The clock switch (CLKSW) control bit may be read or written at any time.
Development Support
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 197
15.4.1.1 BDC Status and Control Register (BDCSCR)
This register can be read or written by serial BDC commands (READ_STATUS and WRITE_CONTROL)
but is not accessible to user programs because it is not located in the normal memory map of the MCU.
76543210
R
ENBDM
BDMACT
BKPTEN FTS CLKSW
WS WSF DVF
W
Normal
Reset
00000000
Reset in
Active BDM:
11001000
= Unimplemented or Reserved
Figure 15-5. BDC Status and Control Register (BDCSCR)
Table 15-2. BDCSCR Register Field Descriptions
Field Description
7
ENBDM
Enable BDM (Permit Active Background Mode) — Typically, this bit is written to 1 by the debug host shortly
after the beginning of a debug session or whenever the debug host resets the target and remains 1 until a normal
reset clears it.
0 BDM cannot be made active (non-intrusive commands still allowed)
1 BDM can be made active to allow active background mode commands
6
BDMACT
Background Mode Active Status — This is a read-only status bit.
0 BDM not active (user application program running)
1 BDM active and waiting for serial commands
5
BKPTEN
BDC Breakpoint Enable — If this bit is clear, the BDC breakpoint is disabled and the FTS (force tag select)
control bit and BDCBKPT match register are ignored.
0 BDC breakpoint disabled
1 BDC breakpoint enabled
4
FTS
Force/Tag Select — When FTS = 1, a breakpoint is requested whenever the CPU address bus matches the
BDCBKPT match register. When FTS = 0, a match between the CPU address bus and the BDCBKPT register
causes the fetched opcode to be tagged. If this tagged opcode ever reaches the end of the instruction queue,
the CPU enters active background mode rather than executing the tagged opcode.
0 Tag opcode at breakpoint address and enter active background mode if CPU attempts to execute that
instruction
1 Breakpoint match forces active background mode at next instruction boundary (address need not be an
opcode)
3
CLKSW
Select Source for BDC Communications Clock — CLKSW defaults to 0, which selects the alternate BDC
clock source.
0 Alternate BDC clock source
1 MCU bus clock
Development Support
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
198 Freescale Semiconductor
15.4.1.2 BDC Breakpoint Match Register (BDCBKPT)
This 16-bit register holds the address for the hardware breakpoint in the BDC. The BKPTEN and FTS
control bits in BDCSCR are used to enable and configure the breakpoint logic. Dedicated serial BDC
commands (READ_BKPT and WRITE_BKPT) are used to read and write the BDCBKPT register but is
not accessible to user programs because it is not located in the normal memory map of the MCU.
Breakpoints are normally set while the target MCU is in active background mode before running the user
application program. For additional information about setup and use of the hardware breakpoint logic in
the BDC, refer to Section 15.2.4, “BDC Hardware Breakpoint.”
15.4.2 System Background Debug Force Reset Register (SBDFR)
This register contains a single write-only control bit. A serial active background mode command such as
WRITE_BYTE must be used to write to SBDFR. Attempts to write this register from a user program are
ignored. Reads always return 0x00.
2
WS
Wait or Stop Status — When the target CPU is in wait or stop mode, most BDC commands cannot function.
However, the BACKGROUND command can be used to force the target CPU out of wait or stop and into active
background mode where all BDC commands work. Whenever the host forces the target MCU into active
background mode, the host should issue a READ_STATUS command to check that BDMACT = 1 before
attempting other BDC commands.
0 Target CPU is running user application code or in active background mode (was not in wait or stop mode when
background became active)
1 Target CPU is in wait or stop mode, or a BACKGROUND command was used to change from wait or stop to
active background mode
1
WSF
Wait or Stop Failure Status — This status bit is set if a memory access command failed due to the target CPU
executing a wait or stop instruction at or about the same time. The usual recovery strategy is to issue a
BACKGROUND command to get out of wait or stop mode into active background mode, repeat the command
that failed, then return to the user program. (Typically, the host would restore CPU registers and stack values and
re-execute the wait or stop instruction.)
0 Memory access did not conflict with a wait or stop instruction
1 Memory access command failed because the CPU entered wait or stop mode
0
DVF
Data Valid Failure Status — This status bit is not used in the MC9S08RC/RD/RE/RG because it does not have
any slow access memory.
0 Memory access did not conflict with a slow memory access
1 Memory access command failed because CPU was not finished with a slow memory access
Table 15-2. BDCSCR Register Field Descriptions (continued)
Field Description
Development Support
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 199
Figure 15-6. System Background Debug Force Reset Register (SBDFR)
15.4.3 DBG Registers and Control Bits
The debug module includes nine bytes of register space for three 16-bit registers and three 8-bit control
and status registers. These registers are located in the high register space of the normal memory map so
they are accessible to normal application programs. These registers are rarely if ever accessed by normal
user application programs with the possible exception of a ROM patching mechanism that uses the
breakpoint logic.
15.4.3.1 Debug Comparator A High Register (DBGCAH)
This register contains compare value bits for the high-order eight bits of comparator A. This register is
forced to 0x00 at reset and can be read at any time or written at any time unless ARM = 1.
15.4.3.2 Debug Comparator A Low Register (DBGCAL)
This register contains compare value bits for the low-order eight bits of comparator A. This register is
forced to 0x00 at reset and can be read at any time or written at any time unless ARM = 1.
15.4.3.3 Debug Comparator B High Register (DBGCBH)
This register contains compare value bits for the high-order eight bits of comparator B. This register is
forced to 0x00 at reset and can be read at any time or written at any time unless ARM = 1.
15.4.3.4 Debug Comparator B Low Register (DBGCBL)
This register contains compare value bits for the low-order eight bits of comparator B. This register is
forced to 0x00 at reset and can be read at any time or written at any time unless ARM = 1.
76543210
R00000000
W BDFR1
1BDFR is writable only through serial active background mode debug commands, not from user programs.
Reset 00010000
= Unimplemented or Reserved
Table 15-3. SBDFR Register Field Description
Field Description
0
BDFR
Background Debug Force Reset — A serial active background mode command such as WRITE_BYTE allows
an external debug host to force a target system reset. Writing 1 to this bit forces an MCU reset. This bit cannot
be written from a user program.
Development Support
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
200 Freescale Semiconductor
15.4.3.5 Debug FIFO High Register (DBGFH)
This register provides read-only access to the high-order eight bits of the FIFO. Writes to this register have
no meaning or effect. In the event-only trigger modes, the FIFO only stores data into the low-order byte of
each FIFO word, so this register is not used and will read 0x00.
Reading DBGFH does not cause the FIFO to shift to the next word. When reading 16-bit words out of the
FIFO, read DBGFH before reading DBGFL because reading DBGFL causes the FIFO to advance to the
next word of information.
15.4.3.6 Debug FIFO Low Register (DBGFL)
This register provides read-only access to the low-order eight bits of the FIFO. Writes to this register have
no meaning or effect.
Reading DBGFL causes the FIFO to shift to the next available word of information. When the debug
module is operating in event-only modes, only 8-bit data is stored into the FIFO (high-order half of each
FIFO word is unused). When reading 8-bit words out of the FIFO, simply read DBGFL repeatedly to get
successive bytes of data from the FIFO. It isn’t necessary to read DBGFH in this case.
Do not attempt to read data from the FIFO while it is still armed (after arming but before the FIFO is filled
or ARMF is cleared) because the FIFO is prevented from advancing during reads of DBGFL. This can
interfere with normal sequencing of reads from the FIFO.
Reading DBGFL while the debugger is not armed causes the address of the most-recently fetched opcode
to be stored to the last location in the FIFO. By reading DBGFH then DBGFL periodically, external host
software can develop a profile of program execution. After eight reads from the FIFO, the ninth read will
return the information that was stored as a result of the first read. To use the profiling feature, read the FIFO
eight times without using the data to prime the sequence and then begin using the data to get a delayed
picture of what addresses were being executed. The information stored into the FIFO on reads of DBGFL
(while the FIFO is not armed) is the address of the most-recently fetched opcode.
Development Support
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 201
15.4.3.7 Debug Control Register (DBGC)
This register can be read or written at any time.
76543210
R
DBGEN ARM TAG BRKEN RWA RWAEN RWB RWBEN
W
Reset 00000000
Figure 15-7. Debug Control Register (DBGC)
Table 15-4. DBGC Register Field Descriptions
Field Description
7
DBGEN
Debug Module Enable — Used to enable the debug module. DBGEN cannot be set to 1 if the MCU is secure.
0 DBG disabled
1 DBG enabled
6
ARM
Arm Control — Controls whether the debugger is comparing and storing information in the FIFO. A write is used
to set this bit (and ARMF) and completion of a debug run automatically clears it. Any debug run can be manually
stopped by writing 0 to ARM or to DBGEN.
0 Debugger not armed
1 Debugger armed
5
TAG
Tag/Force Select — Controls whether break requests to the CPU will be tag or force type requests. If
BRKEN = 0, this bit has no meaning or effect.
0 CPU breaks requested as force type requests
1 CPU breaks requested as tag type requests
4
BRKEN
Break Enable — Controls whether a trigger event will generate a break request to the CPU. Trigger events can
cause information to be stored in the FIFO without generating a break request to the CPU. For an end trace, CPU
break requests are issued to the CPU when the comparator(s) and R/W meet the trigger requirements. For a
begin trace, CPU break requests are issued when the FIFO becomes full. TRGSEL does not affect the timing of
CPU break requests.
0 CPU break requests not enabled
1 Triggers cause a break request to the CPU
3
RWA
R/W Comparison Value for Comparator A — When RWAEN = 1, this bit determines whether a read or a write
access qualifies comparator A. When RWAEN = 0, RWA and the R/W signal do not affect comparator A.
0 Comparator A can only match on a write cycle
1 Comparator A can only match on a read cycle
2
RWAEN
Enable R/W for Comparator A — Controls whether the level of R/W is considered for a comparator A match.
0 R/W is not used in comparison A
1 R/W is used in comparison A
1
RWB
R/W Comparison Value for Comparator B — When RWBEN = 1, this bit determines whether a read or a write
access qualifies comparator B. When RWBEN = 0, RWB and the R/W signal do not affect comparator B.
0 Comparator B can match only on a write cycle
1 Comparator B can match only on a read cycle
0
RWBEN
Enable R/W for Comparator B — Controls whether the level of R/W is considered for a comparator B match.
0 R/W is not used in comparison B
1 R/W is used in comparison B
Development Support
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
202 Freescale Semiconductor
15.4.3.8 Debug Trigger Register (DBGT)
This register can be read any time, but may be written only if ARM = 0, except bits 4 and 5 are hard-wired
to 0s.
76543210
R
TRGSEL BEGIN
00
TRG3 TRG2 TRG1 TRG0
W
Reset 00000000
= Unimplemented or Reserved
Figure 15-8. Debug Trigger Register (DBGT)
Table 15-5. DBGT Register Field Descriptions
Field Description
7
TRGSEL
Trigger Type — Controls whether the match outputs from comparators A and B are qualified with the opcode
tracking logic in the debug module. If TRGSEL is set, a match signal from comparator A or B must propagate
through the opcode tracking logic and a trigger event is only signalled to the FIFO logic if the opcode at the match
address is actually executed.
0 Trigger on access to compare address (force)
1 Trigger if opcode at compare address is executed (tag)
6
BEGIN
Begin/End Trigger Select — Controls whether the FIFO starts filling at a trigger or fills in a circular manner until
a trigger ends the capture of information. In event-only trigger modes, this bit is ignored and all debug runs are
assumed to be begin traces.
0 Data stored in FIFO until trigger (end trace)
1 Trigger initiates data storage (begin trace)
3:0
TRG[3:0]
Select Trigger Mode — Selects one of nine triggering modes, as described below.
0000 A-only
0001 A OR B
0010 A Then B
0011 Event-only B (store data)
0100 A then event-only B (store data)
0101 A AND B data (full mode)
0110 A AND NOT B data (full mode)
0111 Inside range: A ≤ address ≤ B
1000 Outside range: address < A or address > B
1001 – 1111 (No trigger)
Development Support
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 203
15.4.3.9 Debug Status Register (DBGS)
This is a read-only status register.
76543210
R AF BF ARMF 0 CNT3 CNT2 CNT1 CNT0
W
Reset 00000000
= Unimplemented or Reserved
Figure 15-9. Debug Status Register (DBGS)
Table 15-6. DBGS Register Field Descriptions
Field Description
7
AF
Trigger Match A Flag — AF is cleared at the start of a debug run and indicates whether a trigger match A
condition was met since arming.
0 Comparator A has not matched
1 Comparator A match
6
BF
Trigger Match B Flag — BF is cleared at the start of a debug run and indicates whether a trigger match B
condition was met since arming.
0 Comparator B has not matched
1 Comparator B match
5
ARMF
Arm Flag — While DBGEN = 1, this status bit is a read-only image of ARM in DBGC. This bit is set by writing 1
to the ARM control bit in DBGC (while DBGEN = 1) and is automatically cleared at the end of a debug run. A
debug run is completed when the FIFO is full (begin trace) or when a trigger event is detected (end trace). A
debug run can also be ended manually by writing 0 to ARM or DBGEN in DBGC.
0 Debugger not armed
1 Debugger armed
3:0
CNT[3:0]
FIFO Valid Count — These bits are cleared at the start of a debug run and indicate the number of words of valid
data in the FIFO at the end of a debug run. The value in CNT does not decrement as data is read out of the FIFO.
The external debug host is responsible for keeping track of the count as information is read out of the FIFO.
0000 Number of valid words in FIFO = No valid data
0001 Number of valid words in FIFO = 1
0010 Number of valid words in FIFO = 2
0011 Number of valid words in FIFO = 3
0100 Number of valid words in FIFO = 4
0101 Number of valid words in FIFO = 5
0110 Number of valid words in FIFO = 6
0111 Number of valid words in FIFO = 7
1000 Number of valid words in FIFO = 8
Development Support
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
204 Freescale Semiconductor
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 205
Appendix A
Electrical Characteristics
A.1 Introduction
This section contains electrical and timing specifications.
A.2 Absolute Maximum Ratings
Absolute maximum ratings are stress ratings only, and functional operation at the maxima is not
guaranteed. Stress beyond the limits specified in Table A-1 may affect device reliability or cause
permanent damage to the device. For functional operating conditions, refer to the remaining tables in this
section.
This device contains circuitry protecting against damage due to high static voltage or electrical fields;
however, it is advised that normal precautions be taken to avoid application of any voltages higher than
maximum-rated voltages to this high-impedance circuit. Reliability of operation is enhanced if unused
inputs are tied to an appropriate logic voltage level (for instance, either VSS or VDD) or the programmable
pull-up resistor associated with the pin is enabled.
Table A-1. Absolute Maximum Ratings
Rating Symbol Value Unit
Supply voltage VDD –0.3 to +3.8 V
Maximum current into VDD IDD 120 mA
Digital input voltage VIn –0.3 to VDD + 0.3 V
Instantaneous maximum current
Single pin limit (applies to all port pins)(1),(2),(3)
1. Input must be current limited to the value specified. To determine the value of the required
current-limiting resistor, calculate resistance values for positive (VDD) and negative (VSS) clamp
voltages, then use the larger of the two resistance values.
2. All functional non-supply pins are internally clamped to VSS and VDD.
3. Power supply must maintain regulation within operating VDD range during instantaneous and
operating maximum current conditions. If positive injection current (VIn > VDD) is greater than
IDD, the injection current may flow out of VDD and could result in external power supply going
out of regulation. Ensure external VDD load will shunt current greater than maximum injection
current. This will be the greatest risk when the MCU is not consuming power. Examples are: if
no system clock is present, or if the clock rate is very low (which would reduce overall power
consumption).
ID± 25 mA
Storage temperature range Tstg –55 to 150 °C
Electrical Characteristics
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
206 Freescale Semiconductor
A.3 Thermal Characteristics
This section provides information about operating temperature range, power dissipation, and package
thermal resistance. Power dissipation on I/O pins is usually small compared to the power dissipation in
on-chip logic and voltage regulator circuits and it is user-determined rather than being controlled by the
MCU design. In order to take PI/O into account in power calculations, determine the difference between
actual pin voltage and VSS or VDD and multiply by the pin current for each I/O pin. Except in cases of
unusually high pin current (heavy loads), the difference between pin voltage and VSS or VDD will be very
small.
The average chip-junction temperature (TJ) in °C can be obtained from:
TJ = TA + (PD×θ
JA)Eqn. A-1
where:
TA= Ambient temperature, °C
θJA = Package thermal resistance, junction-to-ambient, °C/W
PD = Pint +PI/O
Pint = IDD × VDD, Watts — chip internal power
PI/O = Power dissipation on input and output pins — user determined
For most applications, PI/O << Pint and can be neglected. An approximate relationship between PDand TJ
(if PI/O is neglected) is:
PD = K ÷ (TJ + 273°C) Eqn. A-2
Solving equations 1 and 2 for K gives:
K = PD× (TA + 273°C) + θJA × (PD)2Eqn. A-3
where K is a constant pertaining to the particular part. K can be determined from equation 3 by measuring
PD (at equilibrium) for a known TA. Using this value of K, the values of PD and TJ can be obtained by
solving equations 1 and 2 iteratively for any value of TA.
Table A-2. Thermal Characteristics
Rating Symbol Value Unit
Operating temperature range (packaged) TA
TL to TH
–40 to 85 °C
Thermal resistance
28-pin PDIP
28-pin SOIC
32-pin LQFP
44-pin LQFP
48-pin QFN
θJA 75
70
72
70
82
°C/W
Electrical Characteristics
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 207
A.4 Electrostatic Discharge (ESD) Protection Characteristics
Although damage from static discharge is much less common on these devices than on early CMOS
circuits, normal handling precautions should be used to avoid exposure to static discharge. Qualification
tests are performed to ensure that these devices can withstand exposure to reasonable levels of static
without suffering any permanent damage. All ESD testing is in conformity with CDF-AEC-Q00 Stress
Test Qualification for Automotive Grade Integrated Circuits. (http://www.aecouncil.com/) A device is
considered to have failed if, after exposure to ESD pulses, the device no longer meets the device
specification requirements. Complete dc parametric and functional testing is performed per the applicable
device data sheet at room temperature followed by hot temperature, unless specified otherwise in the
device data sheet.
A.5 DC Characteristics
This section includes information about power supply requirements, I/O pin characteristics, and power
supply current in various operating modes.
Table A-3. ESD Protection Characteristics
Parameter Symbol Value Unit
ESD Target for Machine Model (MM)
MM circuit description
VTHMM 200 V
ESD Target for Human Body Model (HBM)
HBM circuit description
VTHHBM 2000 V
Table A-4. DC Characteristics (Temperature Range = 0 to 70°C Ambient)
Parameter Symbol Min Typical Max Unit
Low-voltage detection threshold VLVD 1.82 1.875 1.90 V
Power on reset (POR) voltage VPOR 0.8 0.9 1.1 V
Maximum low-voltage safe state re-arm(1)
1. If SAFE bit is set, VDD must be above re-arm voltage to allow MCU to accept interrupts, refer to Section 5.6, “Low-Voltage
Detect (LVD) System.”
VREARM 1.90 2.24 2.60 V
Table A-5. DC Characteristics (Temperature Range = –40 to 85°C Ambient)
Parameter Symbol Min Typical Max Unit
Supply voltage (run, wait and stop modes.)
0 < fBus < 8 MHz VDD 1.8 3.6 V
Minimum RAM retention supply voltage applied to VDD VRAM VPOR(1), (2) —V
Low-voltage detection threshold
(VDD falling)
(VDD rising)
VLVD
1.82
1.92
1.88
1.96
1.93
2.01
V
Low-voltage warning threshold
(VDD falling)
(VDD rising)
VLVW
2.07
2.16
2.13
2.21
2.18
2.26
V
Power on reset (POR) voltage VPOR 0.85 1.0 1.2 V
Electrical Characteristics
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
208 Freescale Semiconductor
Maximum low-voltage safe state re-arm(3) VREARM — — 3.0 V
Input high voltage (VDD > 2.3 V) (all digital inputs) VIH 0.70 × VDD —V
Input high voltage (1.8 V ≤ VDD ≤2.3 V) (all digital inputs) VIH 0.85 × VDD —V
Input low voltage (VDD > 2.3 V) (all digital inputs) VIL — 0.35 ×
VDD
V
Input low voltage (1.8 V ≤ VDD ≤2.3 V)
(all digital inputs)
VIL — 0.30 ×
VDD
V
Input hysteresis (all digital inputs) Vhys 0.06 × VDD —V
Input leakage current (Per pin)
VIn = VDD or VSS, all input only pins
|IIn| — 0.025 1.0 µA
High impedance (off-state) leakage current (per pin)
VIn = VDD or VSS, all input/output
|IOZ| — 0.025 1.0 µA
Internal pullup resistors(4) (5) RPU 17.5 52.5 κW
Internal pulldown resistor (IRQ) RPD 17.5 52.5 κW
Output high voltage (VDD ≥ 1.8 V)
IOH = –2 mA (ports A, C, D and E) VOH VDD – 0.5 — V
Output high voltage (port B and IRO)
IOH = –10 mA (VDD ≥ 2.7 V)
IOH = –6 mA (VDD ≥ 2.3 V)
IOH = –3 mA (VDD ≥ 1.8 V)
VDD – 0.5
—
—
—
Maximum total IOH for all port pins |IOHT| — 60 mA
Output low voltage (VDD ≥ 1.8 V)
IOL = 2.0 mA (ports A, C, D and E)
VOL
— 0.5 V
Output low voltage (port B)
IOL = 10.0 mA (VDD ≥ 2.7 V)
IOL = 6 mA (VDD ≥ 2.3 V)
IOL = 3 mA (VDD ≥ 1.8 V)
—
—
—
0.5
0.5
0.5
Output low voltage (IRO)
IOL = 16 mA (VDD ≥ 2.7 V)
IOL = 6 mA (VDD ≥ 2.3 V)
IOL = 3 mA (VDD ≥ 1.8 V)
—
—
—
1.2
1.2
1.2
Maximum total IOL for all port pins IOLT —60mA
dc injection current(2), (6), (7), (8),, (9)
VIN < VSS, VIN > VDD
Single pin limit
Total MCU limit, includes sum of all stressed pins
|IIC|
—
—
0.2
5
mA
mA
Input capacitance (all non-supply pins) CIn —7pF
1. RAM will retain data down to POR voltage. RAM data not guaranteed to be valid following a POR.
2. This parameter is characterized and not tested on each device.
3. If SAFE bit is set, VDD must be above re-arm voltage to allow MCU to accept interrupts, refer to Section 5.6, “Low-Voltage
Detect (LVD) System.”
4. Measurement condition for pull resistors: VIn = VSS for pullup and VIn = VDD for pulldown.
5. The PTA0 pullup resistor may not pull up to the specified minimum VIH. However, all ports are functionally tested to guarantee
that a logic 1 will be read on any port input when the pullup is enabled and no dc load is present on the pin.
6. All functional non-supply pins are internally clamped to VSS and VDD.
Table A-5. DC Characteristics (Temperature Range = –40 to 85°C Ambient) (continued)
Parameter Symbol Min Typical Max Unit
Electrical Characteristics
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 209
Figure A-1. Pullup and Pulldown Typical Resistor Values (VDD = 3.0 V)
Figure A-2. Typical Low-Side Driver (Sink) Characteristics (Port B and IRO)
Figure A-3. Typical Low-Side Driver (Sink) Characteristics (Ports A, C, D and E)
7. Input must be current limited to the value specified. To determine the value of the required current-limiting resistor, calculate
resistance values for positive and negative clamp voltages, then use the larger of the two values.
8. Power supply must maintain regulation within operating VDD range during instantaneous and operating maximum current
conditions. If positive injection current (VIn >V
DD) is greater than IDD, the injection current may flow out of VDD and could result
in external power supply going out of regulation. Ensure external VDD load will shunt current greater than maximum injection
current. This will be the greatest risk when the MCU is not consuming power. Examples are: if no system clock is present, or
if clock rate is very low (which would reduce overall power consumption).
9. PTA0 does not have a clamp diode to VDD. Do not drive PTA0 above VDD.
PULLUP RESISTOR TYPICALS
VDD (V)
PULL-UP RESISTOR (kΩ)
20
25
30
35
40
1.8 2 2.2 2.4 2.6 2.8 3 3.2 3.4 3.6
25°C
85°C
–40°C
PULLDOWN RESISTOR TYPICALS
VDD (V)
PULLDOWN RESISTANCE (kΩ)
20
25
30
35
40
1.8 2.3 2.8 3.3
25°C
85°C
–40°C
3.6
TYPICAL VOL VS IOL AT VDD = 3.0 V
IOL (mA)
VOL (V)
0
0.2
0.4
0.6
0.8
1
0102030
TYPI
C
AL VOL V
S
VDD
VDD (V)
VOL (V)
0
0.1
0.2
0.3
0.4
1234
IOL = 6 mA
IOL = 3 mA
IOL = 10 mA
25°C
85°C
–40°C 25°C
85°C
–40°C
TYPICAL VOL VS IOL AT VDD = 3.0 V
IOL (mA)
VOL (V)
0
0.2
0.4
0.6
0.8
1
1.2
0 5 10 15 20
TYPICAL VOL VS VDD
VDD (V)
VOL (V)
0
0.05
0.1
0.15
0.2
1234
25°C
85°C
–40°C
25°C,
IOL = 2 mA
85°C,
IOL = 2 mA
–40°C,
IOL = 2 mA
Electrical Characteristics
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
210 Freescale Semiconductor
Figure A-4. Typical High-Side Driver (Source) Characteristics (Port B and IRO)
Figure A-5. Typical High-Side (Source) Characteristics (Ports A, C, D and E)
TYPICAL VDD – VOH VS IOH AT VDD = 3.0 V
IOH (mA)
0
0.2
0.4
0.6
0.8
–30–25–20–15–10–50
TYPICAL VDD – VOH VS VDD AT SPEC IOH
VDD (V)
VDD – VOH (V)
0
0.1
0.2
0.3
0.4
1234
IOH = –10 mA
IOH = –6 mA
IOH = –3 mA
VDD – VOH (V)
25°C
85°C
–40°C
25°C
85°C
–40°C
TYPICAL VDD – VOH VS IOH AT VDD = 3.0 V
IOH (mA))
0
0.2
0.4
0.6
0.8
1
1.2
–20–15–10–50
TYPICAL VDD – VOH VS VDD AT SPEC IOH
VDD (V)
VDD – VOH (V)
0
0.05
0.1
0.15
0.2
0.25
1234
VDD – VOH (V)
25°C
85°C
–40°C
25°C,
IOH = 2 mA
85°C,
IOH = 2 mA
–40°C,
IOH = 2 mA
Electrical Characteristics
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 211
A.6 Supply Current Characteristics
A.7 Analog Comparator (ACMP) Electricals
Table A-6. Supply Current Characteristics
Parameter Symbol VDD (V)(1)
1. 3 V values are 100% tested; 2 V values are characterized but not tested.
Typical(2)
2. Typicals are measured at 25°C.
Max Temp. (°C)
Run supply current(3) measured at
(CPU clock = 2 MHz, fBus = 1 MHz)
3. Does not include any dc loads on port pins
RIDD 3 500 µA 1.525 mA
1.525 mA
70
85
2 450 µA 1.475 mA
1.475 mA
70
85
Run supply current(3) measured at
(CPU clock = 16 MHz, fBus = 8 MHz)
RIDD 3 3.8 mA 4.8 mA
4.8 mA
70
85
2 2.6 mA 3.6 mA
3.6 mA
70
85
Stop1 mode supply current
S1IDD
3 100 nA 350 nA
736 nA
70
85
2 100 nA 150 nA
450 nA
70
85
Stop2 mode supply current
S2IDD
3 500 nA 1.20 µA
1.90 µA
70
85
2 500 nA 1.00 µA
1.70 µA
70
85
Stop3 mode supply current
S3IDD
3 600 nA 2.65 µA
4.65 µA
70
85
2 500 nA 2.30 µA
4.30 µA
70
85
RTI adder from stop2 or stop3 3 300 nA
2 300 nA
Adder for LVD reset enabled in stop3 3 70 µA
260µA
Table A-7. ACMP Electrical Specifications (Temp Range = -40 to 85°C Ambient)
Characteristic Symbol Min Typical Max Unit
Analog input voltage VAIN VSS – 0.3 — VDD V
Analog input offset voltage VAIO — 40 mV
Analog Comparator initialization delay tAINIT —1 µs
Analog Comparator bandgap reference voltage VBG 1.208 1.218 1.228 V
Electrical Characteristics
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
212 Freescale Semiconductor
A.8 Oscillator Characteristics
A.9 AC Characteristics
This section describes ac timing characteristics for each peripheral system.
A.9.1 Control Timing
Table A-8. OSC Electrical Specifications (Temperature Range = -40 to 85°C Ambient)
Characteristic Symbol Min Typ(1)
1. Data in typical column was characterized at 3.0 V, 25°C or is typical recommended value.
Max Unit
Frequency fOSC 1 — 16 MHz
Load Capacitors C1
C2
Note(2)
2. See crystal or resonator manufacturer’s recommendation.
Feedback resistor RF1MΩ
Table A-9. Control Timing
Parameter Symbol Min Typical Max Unit
Bus frequency (tcyc = 1/fBus)f
Bus dc — 8 MHz
Real time interrupt internal oscillator period tRTI 400 1600 µs
External reset pulse width(1)
1. This is the shortest pulse that is guaranteed to be recognized as a reset pin request. Shorter pulses are not guaranteed to
override reset requests from internal sources.
textrst 1.5 tcyc —ns
Reset low drive(2) trstdrv 34 tcyc —ns
Active background debug mode latch setup time tMSSU 25 — ns
Active background debug mode latch hold time tMSH 25 — ns
IRQ pulse width(3) tILIH 1.5 tcyc —ns
Port rise and fall time (load = 50 pF)(4) tRise, tFall —3 ns
OSC
EXTAL XTAL
Crystal or Resonator
C2
RF
C1
Electrical Characteristics
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 213
Figure A-6. Reset Timing
Figure A-7. Active Background Debug Mode Latch Timing
Figure A-8. IRQ Timing
A.9.2 Timer/PWM (TPM) Module Timing
Synchronizer circuits determine the shortest input pulses that can be recognized or the fastest clock that
can be used as the optional external source to the timer counter. These synchronizers operate from the
current bus rate clock.
2. When any reset is initiated, internal circuitry drives the reset pin low for about 34 cycles of fBus and then samples the level on
the reset pin about 38 cycles later to distinguish external reset requests from internal requests.
3. This is the minimum pulse width that is guaranteed to pass through the pin synchronization circuitry. Shorter pulses may or
may not be recognized. In stop mode, the synchronizer is bypassed so shorter pulses can be recognized in that case.
4. Timing is shown with respect to 20% VDD and 80% VDD levels. Temperature range –40°C to 85°C.
textrst
RESET PIN
BKGD/MS
RESET
tMSSU
tMSH
tILIH
IRQ
Electrical Characteristics
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
214 Freescale Semiconductor
Figure A-9. Timer External Clock
Figure A-10. Timer Input Capture Pulse
A.9.3 SPI Timing
Table A-11 and Figure A-11 through Figure A-14 describe the timing requirements for the SPI system.
Table A-10. TPM Input Timing
Function Symbol Min Max Unit
External clock frequency fTPMext dc fBus/4 MHz
External clock period tTPMext 4—t
cyc
External clock high time tclkh 1.5 — tcyc
External clock low time tclkl 1.5 — tcyc
Input capture pulse width tICPW 1.5 — tcyc
tText
tclkh
tclkl
TPM1CHn
tICPW
TPM1CHn
tICPW
TPM1CHn
Electrical Characteristics
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 215
Table A-11. SPI Electrical Characteristic
Number(1)
1. Refer to Figure A-11 through Figure A-14.
Characteristic(2)
2. All timing is shown with respect to 20% VDD and 70% VDD, unless noted; 100 pF load on all
SPI pins. All timing assumes slew rate control disabled and high drive strength enabled for SPI
output pins.
Symbol Min Max Unit
Operating frequency(3)
Master
Slave
3. Maximum baud rate must be limited to 5 MHz due to pad input characteristics.
fop
fop
fBus/2048
dc
fBus/2
fBus/4
Hz
1 Cycle time
Master
Slave
tSCK
tSCK
2
4
2048
—
tcyc
tcyc
2 Enable lead time
Master
Slave
tLead
tLead
—
1/2
1/2
—
tSCK
tSCK
3 Enable lag time
Master
Slave
tLag
tLag
—
1/2
1/2
—
tSCK
tSCK
4 Clock (SPSCK) high time
Master and Slave tSCKH 1/2 tSCK – 25 — ns
5 Clock (SPSCK) low time
Master and Slave tSCKL 1/2 tSCK – 25 — ns
6 Data setup time (inputs)
Master
Slave
tSI(M)
tSI(S)
30
30
—
—
ns
ns
7 Data hold time (inputs)
Master
Slave
tHI(M)
tHI(S)
30
30
—
—
ns
ns
8 Access time, slave(4)
4. Time to data active from high-impedance state.
tA040ns
9 Disable time, slave(5)
5. Hold time to high-impedance state.
tdis —40ns
10 Data setup time (outputs)
Master
Slave
tSO
tSO
25
25
—
—
ns
ns
11 Data hold time (outputs)
Master
Slave
tHO
tHO
–10
–10
—
—
ns
ns
Electrical Characteristics
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
216 Freescale Semiconductor
Figure A-11. SPI Master Timing (CPHA = 0)
Figure A-12. SPI Master Timing (CPHA = 1)
SCK
(OUTPUT)
SCK
(OUTPUT)
MISO
(INPUT)
MOSI
(OUTPUT)
SS1
(OUTPUT)
MSB IN2
BIT 6 . . . 1
LSB IN
MSB OUT2LSB OUT
BIT 6 . . . 1
(CPOL = 0)
(CPOL = 1)
NOTES:
2. LSBF = 0. For LSBF = 1, bit order is LSB, bit 1, ..., bit 6, MSB.
1. SS output mode (MODFEN = 1, SSOE = 1).
<
<<s
<
<<
<st <s
<
<s
<
<
SCK
(OUTPUT)
SCK
(OUTPUT)
MISO
(INPUT)
MOSI
(OUTPUT)
MSB IN(2)
BIT 6 . . . 1
LSB IN
MSB OUT(2) LSB OUT
BIT 6 . . . 1
(CPOL = 0)
(CPOL = 1)
SS(1)
(OUTPUT)
1. SS output mode (MODFEN = 1, SSOE = 1).
2. LSBF = 0. For LSBF = 1, bit order is LSB, bit 1, ..., bit 6, MSB.
NOTES:
<
<
<s
<
<
<<
<s <s
<
<
Electrical Characteristics
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 217
Figure A-13. SPI Slave Timing (CPHA = 0)
Figure A-14. SPI Slave Timing (CPHA = 1)
SCK
(INPUT)
SCK
(INPUT)
MOSI
(INPUT)
MISO
(OUTPUT)
SS
(INPUT)
MSB IN
BIT 6 . . . 1
LSB IN
MSB OUT SLAVE LSB OUT
BIT 6 . . . 1
(CPOL = 0)
(CPOL = 1)
NOTE:
SLAVE SEE
NOTE
1. Not defined but normally MSB of character just received
<
<
<s
<
<<
<
<
<s <st-
<
<
<
SCK
(INPUT)
SCK
(INPUT)
MOSI
(INPUT)
MISO
(OUTPUT)
MSB IN
BIT 6 . . . 1
LSB IN
MSB OUT SLAVE LSB OUT
BIT 6 . . . 1
SEE
(CPOL = 0)
(CPOL = 1)
SS
(INPUT)
NOTE:
SLAVE
NOTE
1. Not defined but normally LSB of character just received
<
<
<s
<
<<
<
<
<st <st
<
<
<
Electrical Characteristics
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
218 Freescale Semiconductor
A.10 FLASH Specifications
This section provides details about program/erase times and program-erase endurance for the FLASH
memory.
Program and erase operations do not require any special power sources other than the normal VDD supply.
For more detailed information about program/erase operations, see the Memory chapter.
Table A-12. FLASH Characteristics
Characteristic Symbol Min Typical Max Unit
Supply voltage for program/erase Vprog/erase 2.05 3.6 V
Supply voltage for read operation
0 < fBus < 8 MHz
VRead
1.8 3.6
V
Internal FCLK frequency(1)
1. The frequency of this clock is controlled by a software setting.
fFCLK 150 200 kHz
Internal FCLK period (1/FCLK) tFcyc 5 6.67 µs
Byte program time (random location)(2) tprog 9t
Fcyc
Byte program time (burst mode)(2) tBurst 4t
Fcyc
Page erase time(2)
2. These values are hardware state machine controlled. User code does not need to count cycles. This information
supplied for calculating approximate time to program and erase.
tPage 4000 tFcyc
Mass erase time(2) tMass 20,000 tFcyc
Program/erase endurance(3)
TL to TH = –40°C to + 85°C
T = 25°C
3. Typical endurance for FLASH was evaluated for this product family on the 9S12Dx64. For additional
information on how Freescale Semiconductor defines typical endurance, please refer to Engineering Bulletin
EB619/D, Typical Endurance for Nonvolatile Memory.
10,000
100,000
—
—
cycles
Data retention(4)
4. Typical data retention values are based on intrinsic capability of the technology measured at high temperature
and de-rated to 25°C using the Arrhenius equation. For additional information on how Freescale Semiconductor
defines typical data retention, please refer to Engineering Bulletin EB618/D, Typical Data Retention for
Nonvolatile Memory.
tD_ret 15 100 — years
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor 219
Appendix A
Appendix B
Ordering Information and Mechanical Drawings
B.1 Ordering Information
This section contains generic ordering information for MC9S08RD/RE/RG devices and an example of the
device numbering syste m.
See Table B-1 for package availability for each MC9S08RD/RE/RG devic e.
B.2 Mecha nical Dra wi ngs
The following pages are mechanical drawings for these packages:
• 28-Pin PDIP
• 28-Pin SOIC
• 32-Pin LQFP
• 44-Pin LQFP
• 48-Pin QFN
Table B-1. Package Descriptions
Pin Count Type Abbreviation Designator Document No.
28 Plastic Dual In-Line Package PDIP P 98ASB42390B
28 Small Outline Integrat ed Circuit SOIC DW 9 8ASB42345B
32 Low Quad Flat Package LQFP FJ 9 8ASH70029A
44 Low Quad Flat Package LQFP FG 98ASB42885B
48 Quad Flat Package QFN FD 98ARH99048A
MC 9 S08 RG6 0 C XX E
Derivative
Memory t ype ( 9 = FLASH)
Status
Core
Package designator
Indicates RoHS-compliant packaging
Temperature range
designator
C = –40 thru 85°C
Blan k = 0 th ru 70°C
MC9S08RG60/D
Rev. 1.11
How to Reach Us:
USA/Europe/Locations not listed:
Freescale Semiconductor Literature Distribution
P.O. Box 5405, Denver, Colorado 80217
1-800-521-6274 or 480-768-2130
Japan:
Freescale Semiconductor Japan Ltd.
SPS, Technical Information Center
3-20-1, Minami-Azabu
Minato-ku
Tokyo 106-8573, Japan
81-3-3440-3569
Asia/Pacific:
Freescale Semiconductor H.K. Ltd.
2 Dai King Street
Tai Po Industrial Estate
Tai Po, N.T. Hong Kong
852-26668334
Learn More:
For more information about Freescale
Semiconductor products, please visit
http://www.freescale.com
Information in this document is provided solely to enable system and software implementers to use
Freescale Semiconductor products. There are no express or implied copyright licenses granted
hereunder to design or fabricate any integrated circuits or integrated circuits based on the information
in this document.
Freescale Semiconductor reserves the right to make changes without further notice to any products
herein. Freescale Semiconductor makes no warranty, representation or guarantee regarding the
suitability of its products for any particular purpose, nor does Freescale Semiconductor assume any
liability arising out of the application or use of any product or circuit, and specifically disclaims any
and all liability, including without limitation consequential or incidental damages. “Typical” parameters
which may be provided in Freescale Semiconductor data sheets and/or specifications can and do
vary in different applications and actual performance may vary over time. All operating parameters,
including “Typicals” must be validated for each customer application by customer’s technical experts.
Freescale Semiconductor does not convey any license under its patent rights nor the rights of others.
Freescale Semiconductor products are not designed, intended, or authorized for use as components
in systems intended for surgical implant into the body, or other applications intended to support or
sustain life, or for any other application in which the failure of the Freescale Semiconductor product
could create a situation where personal injury or death may occur. Should Buyer purchase or use
Freescale Semiconductor products for any such unintended or unauthorized application, Buyer shall
indemnify and hold Freescale Semiconductor and its officers, employees, subsidiaries, affiliates, and
distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney
fees arising out of, directly or indirectly, any claim of personal injury or death associated with such
unintended or unauthorized use, even if such claim alleges that Freescale Semiconductor was
negligent regarding the design or manufacture of the part.
Freescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other
product or service names are the property of their respective owners.
© Freescale Semiconductor, Inc. 2004. All rights reserved.
RoHS-compliant and/or Pb- free versions of Freescale products have the functionality
and electrical characteristics of their non-RoHS-compliant and/or non-Pb- free
counterparts. For further information, see http://www.freescale.com or contact your
Freescale sales representative.
For information on Freescale.s Environmental Products program, go to
http://www.freescale.com/epp.
RoHS-compliant and/or Pb- free versions of Freescale products have the functionality
and electrical characteristics of their non-RoHS-compliant and/or non-Pb- free
counterparts. For further information, see http://www.freescale.com or contact your
Freescale sales representative.
For information on Freescale.s Environmental Products program, go to
http://www.freescale.com/epp.
RoHS-compliant and/or Pb- free versions of Freescale products have the functionality
and electrical characteristics of their non-RoHS-compliant and/or non-Pb- free
counterparts. For further information, see http://www.freescale.com or contact your
Freescale sales representative.
For information on Freescale.s Environmental Products program, go to
http://www.freescale.com/epp.
RoHS-compliant and/or Pb- free versions of Freescale products have the functionality
and electrical characteristics of their non-RoHS-compliant and/or non-Pb- free
counterparts. For further information, see http://www.freescale.com or contact your
Freescale sales representative.
For information on Freescale.s Environmental Products program, go to
http://www.freescale.com/epp.
