ST72F521, ST72521B 80/64-PIN 8-BIT MCU WITH 32 TO 60K FLASH/ROM, ADC, FIVE TIMERS, SPI, SCI, I2C, CAN INTERFACE Memories - 32K to 60K dual voltage High Density Flash (HDFlash) or ROM with read-out protection capability. In-Application Programming and In-Circuit Programming for HDFlash devices - 1K to 2K RAM - HDFlash endurance: 100 cycles, data retention: 20 years at 55C Clock, Reset And Supply Management - Enhanced low voltage supervisor (LVD) for main supply and auxiliary voltage detector (AVD) with interrupt capability - Clock sources: crystal/ceramic resonator oscillators, internal RC oscillator and bypass for external clock - PLL for 2x frequency multiplication - Four power saving modes: Halt, Active-Halt, Wait and Slow Interrupt Management - Nested interrupt controller - 14 interrupt vectors plus TRAP and RESET - Top Level Interrupt (TLI) pin - 15 external interrupt lines (on 4 vectors) Up to 64 I/O Ports - 48 multifunctional bidirectional I/O lines - 34 alternate function lines - 16 high sink outputs 5 Timers - Main Clock Controller with: Real time base, Beep and Clock-out capabilities - Configurable watchdog timer - Two 16-bit timers with: 2 input captures, 2 output compares, external clock input on one timer, PWM and pulse generator modes - 8-bit PWM Auto-Reload timer with: 2 input captures, 4 PWM outputs, output compare and time base interrupt, external clock with event detector TQFP64 14 x 14 TQFP80 14 x 14 TQFP64 10 x 10 4 Communications Interfaces - SPI synchronous serial interface - SCI asynchronous serial interface - I2C multimaster interface (SMbus V1.1 compliant) - CAN interface (2.0B Passive) Analog periperal (low current coupling) - 10-bit ADC with 16 input robust input ports Instruction Set - 8-bit Data Manipulation - 63 Basic Instructions - 17 main Addressing Modes - 8 x 8 Unsigned Multiply Instruction Development Tools - Full hardware/software development package - In-Circuit Testing capability Device Summary Features ST72F521(M/R/AR)9 ST72F521(R/AR)6 ST72521B(M/R/AR)9 ST72521B(R/AR)6 Program memory - bytes RAM (stack) - bytes Operating Voltage Temp. Range Flash 60K 2048 (256) Flash 32K 1024 (256) ROM 60K 2048 (256) ROM 32K 1024 (256) Package TQFP80 14x14 (M), TQFP64 14x14 (R), TQFP64 10x10 (AR) 3.8V to 5.5V up to -40C to +125 C TQFP80 14x14 (M), TQFP64 14x14 (R), TQFP64 TQFP64 14x14 (R), 10x10 (AR) TQFP64 10x10 (AR) TQFP64 14x14 (R), TQFP64 10x10 (AR) Rev. 5 May 2005 1/215 1 Table of Contents 1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2 PIN DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3 REGISTER & MEMORY MAP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 4 FLASH PROGRAM MEMORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 4.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 4.2 MAIN FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 4.3 STRUCTURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 4.3.1 Read-out Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 4.4 ICC INTERFACE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 4.5 ICP (IN-CIRCUIT PROGRAMMING) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 4.6 IAP (IN-APPLICATION PROGRAMMING) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 4.7 RELATED DOCUMENTATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 4.7.1 Register Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 5 CENTRAL PROCESSING UNIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 5.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 5.2 MAIN FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 5.3 CPU REGISTERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 6 SUPPLY, RESET AND CLOCK MANAGEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 6.1 PHASE LOCKED LOOP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 6.2 MULTI-OSCILLATOR (MO) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 6.3 RESET SEQUENCE MANAGER (RSM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 6.3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.3.2 Asynchronous External RESET pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.3.3 External Power-On RESET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.3.4 Internal Low Voltage Detector (LVD) RESET . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.3.5 Internal Watchdog RESET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.4 SYSTEM INTEGRITY MANAGEMENT (SI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 26 27 27 27 28 6.4.1 Low Voltage Detector (LVD) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.4.2 Auxiliary Voltage Detector (AVD) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.4.3 Low Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.4.4 Register Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 INTERRUPTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 29 31 32 33 33 7.2 MASKING AND PROCESSING FLOW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 7.3 INTERRUPTS AND LOW POWER MODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 7.4 CONCURRENT & NESTED MANAGEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 7.5 INTERRUPT REGISTER DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 7.6 EXTERNAL INTERRUPTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 7.6.1 I/O Port Interrupt Sensitivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 7.7 EXTERNAL INTERRUPT CONTROL REGISTER (EICR) . . . . . . . . . . . . . . . . . . . . . . . . . 40 8 POWER SAVING MODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 8.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215 . . . . 42 8.2 SLOW MODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 8.3 WAIT MODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 2/215 1 Table of Contents 8.4 ACTIVE-HALT AND HALT MODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 8.4.1 ACTIVE-HALT MODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.4.2 HALT MODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 I/O PORTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 45 47 47 9.2 FUNCTIONAL DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 9.2.1 Input Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.2.2 Output Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.2.3 Alternate Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.3 I/O PORT IMPLEMENTATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 47 47 50 9.4 LOW POWER MODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 9.5 INTERRUPTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 9.5.1 I/O Port Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 10 ON-CHIP PERIPHERALS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 10.1 WATCHDOG TIMER (WDG) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 10.1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.1.2 Main Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.1.3 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.1.4 How to Program the Watchdog Timeout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.1.5 Low Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.1.6 Hardware Watchdog Option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.1.7 Using Halt Mode with the WDG (WDGHALT option) . . . . . . . . . . . . . . . . . . . . . . . 10.1.8 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.1.9 Register Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.2 MAIN CLOCK CONTROLLER WITH REAL TIME CLOCK AND BEEPER (MCC/RTC) . . 53 53 53 54 56 56 56 56 56 58 10.2.1 Programmable CPU Clock Prescaler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.2.2 Clock-out Capability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.2.3 Real Time Clock Timer (RTC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.2.4 Beeper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.2.5 Low Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.2.6 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.2.7 Register Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.3 PWM AUTO-RELOAD TIMER (ART) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 58 58 58 59 59 59 61 10.3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.3.2 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.3.3 Register Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.4 16-BIT TIMER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 62 66 70 10.4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.4.2 Main Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.4.3 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.4.4 Low Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.4.5 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.4.6 Summary of Timer modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.4.7 Register Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.5 SERIAL PERIPHERAL INTERFACE (SPI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 70 70 82 82 82 83 89 10.5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 10.5.2 Main Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 3/215 1 Table of Contents 10.5.3 General Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 10.5.4 Clock Phase and Clock Polarity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 10.5.5 Error Flags . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 10.5.6 Low Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 10.5.7 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 10.5.8 Register Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 10.6 SERIAL COMMUNICATIONS INTERFACE (SCI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 10.6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.6.2 Main Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.6.3 General Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.6.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.6.5 Low Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.6.6 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.6.7 Register Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.7 I2C BUS INTERFACE (I2C) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 100 100 102 109 109 110 116 10.7.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.7.2 Main Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.7.3 General Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.7.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.7.5 Low Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.7.6 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.7.7 Register Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.8 CONTROLLER AREA NETWORK (CAN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116 116 116 118 122 122 123 129 10.8.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.8.2 Main Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.8.3 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.8.4 Register Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.8.5 List of CAN Cell Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.9 10-BIT A/D CONVERTER (ADC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129 130 130 136 146 155 10.9.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.9.2 Main Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.9.3 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.9.4 Low Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.9.5 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.9.6 Register Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 INSTRUCTION SET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.1 CPU ADDRESSING MODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155 155 156 156 156 157 159 159 11.1.1 Inherent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.1.2 Immediate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.1.3 Direct . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.1.4 Indexed (No Offset, Short, Long) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.1.5 Indirect (Short, Long) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.1.6 Indirect Indexed (Short, Long) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.1.7 Relative mode (Direct, Indirect) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.2 INSTRUCTION GROUPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160 160 160 160 160 161 161 162 12 ELECTRICAL CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215 . . . 165 12.1 PARAMETER CONDITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165 4/215 Table of Contents 12.1.1 Minimum and Maximum values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.1.2 Typical values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.1.3 Typical curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.1.4 Loading capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.1.5 Pin input voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.2 ABSOLUTE MAXIMUM RATINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165 165 165 165 165 166 12.2.1 Voltage Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.2.2 Current Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.2.3 Thermal Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.3 OPERATING CONDITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166 166 167 167 12.3.1 General Operating Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.3.2 Operating Conditions with Low Voltage Detector (LVD) . . . . . . . . . . . . . . . . . . . 12.3.3 Auxiliary Voltage Detector (AVD) Thresholds . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.3.4 External Voltage Detector (EVD) Thresholds . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.4 SUPPLY CURRENT CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167 168 168 168 169 12.4.1 CURRENT CONSUMPTION ..................................... 12.4.2 Supply and Clock Managers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.4.3 On-Chip Peripherals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.5 CLOCK AND TIMING CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169 171 172 173 12.5.1 General Timings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.5.2 External Clock Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.5.3 Crystal and Ceramic Resonator Oscillators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.5.4 RC Oscillators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.5.5 PLL Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.6 MEMORY CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173 173 174 176 177 178 12.6.1 RAM and Hardware Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178 12.6.2 FLASH Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178 12.7 EMC CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179 12.7.1 Functional EMS (Electro Magnetic Susceptibility) . . . . . . . . . . . . . . . . . . . . . . . . 12.7.2 Electro Magnetic Interference (EMI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.7.3 Absolute Maximum Ratings (Electrical Sensitivity) . . . . . . . . . . . . . . . . . . . . . . . 12.8 I/O PORT PIN CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179 180 181 182 12.8.1 General Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182 12.8.2 Output Driving Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183 12.9 CONTROL PIN CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185 12.9.1 Asynchronous RESET Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185 12.9.2 ICCSEL/VPP Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187 12.10TIMER PERIPHERAL CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188 12.10.1 8-Bit PWM-ART Auto-Reload Timer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188 12.10.2 16-Bit Timer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188 12.11COMMUNICATION INTERFACE CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . 189 12.11.1 SPI - Serial Peripheral Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.11.2 I2C - Inter IC Control Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.11.3 CAN - Controller Area Network Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.1210-BIT ADC CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189 191 192 193 12.12.1 Analog Power Supply and Reference Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195 12.12.2 General PCB Design Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195 5/215 Table of Contents 12.12.3 ADC Accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196 13 PACKAGE CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197 13.1 PACKAGE MECHANICAL DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197 13.2 THERMAL CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199 13.3 SOLDERING INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200 14 ST72521 DEVICE CONFIGURATION AND ORDERING INFORMATION . . . . . . . . . . . . . . . 201 14.1 FLASH OPTION BYTES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201 14.2 DEVICE ORDERING INFORMATION AND TRANSFER OF CUSTOMER CODE . . . . . 203 14.2.1 Version-Specific Sales Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203 14.3 DEVELOPMENT TOOLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206 14.3.1 Socket and Emulator Adapter Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207 14.4 ST7 APPLICATION NOTES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208 15 KNOWN LIMITATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211 15.1 ALL FLASH AND ROM DEVICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211 15.1.1 External RC option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.1.2 Safe Connection of OSC1/OSC2 Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.1.3 Reset pin protection with LVD Enabled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.1.4 Unexpected Reset Fetch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.1.5 Clearing active interrupts outside interrupt routine . . . . . . . . . . . . . . . . . . . . . . . 15.1.6 SCI Wrong Break duration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.1.7 16-bit Timer PWM Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.1.8 CAN Cell Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.1.9 I2C Multimaster . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.2 ALL FLASH DEVICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211 211 211 211 211 212 212 212 212 213 15.2.1 Internal RC Oscillator with LVD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.2.2 I/O behaviour during ICC mode entry sequence . . . . . . . . . . . . . . . . . . . . . . . . . 15.2.3 Read-out protection with LVD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 REVISION HISTORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213 213 213 214 215 6/215 ST72F521, ST72521B 1 INTRODUCTION The ST72F521 and ST72521B devices are members of the ST7 microcontroller family designed for mid-range applications with a CAN bus interface (Controller Area Network). All devices are based on a common industrystandard 8-bit core, featuring an enhanced instruction set and are available with FLASH or ROM program memory. Under software control, all devices can be placed in WAIT, SLOW, ACTIVE-HALT or HALT mode, reducing power consumption when the application is in idle or stand-by state. The enhanced instruction set and addressing modes of the ST7 offer both power and flexibility to software developers, enabling the design of highly efficient and compact application code. In addition to standard 8-bit data management, all ST7 microcontrollers feature true bit manipulation, 8x8 unsigned multiplication and indirect addressing modes. Related Documentation AN1131: Migrating applications from ST72511/ 311/314 to ST72521/321/324 Figure 1. Device Block Diagram 8-BIT CORE ALU RESET VPP TLI VSS VDD PROGRAM MEMORY (32K - 60K Bytes) CONTROL RAM (1024-2048 Bytes) LVD EVD AVD OSC1 OSC2 OSC WATCHDOG PORT F PF7:0 (8-bits) TIMER A BEEP ADDRESS AND DATA BUS MCC/RTC/BEEP I2C PORT A PORT B PB7:0 (8-bits) PWM ART PORT C PORT E TIMER B PE7:0 (8-bits) PA7:0 (8-bits) PC7:0 (8-bits) CAN SPI SCI PORT D PORT G1 PG7:0 (8-bits) 10-BIT ADC PORT H1 PH7:0 (8-bits) PD7:0 (8-bits) VAREF VSSA 1On some devices only, see Device Summary on page 1 7/215 ST72F521, ST72521B 2 PIN DESCRIPTION TLI EVD RESET VPP / ICCSEL PA7 (HS) / SCLI PA6 (HS) / SDAI PA5 (HS) PA4 (HS) PH7 PH6 PH5 PH4 OSC2 VSS_2 OSC1 80 79 78 77 76 75 74 73 72 71 70 69 68 67 66 65 64 63 62 61 PE3 / CANRX PE2 / CANTX PE1 / RDI PE0 / TDO VDD_2 Figure 2. 80-Pin TQFP 14x14 Package Pinout 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 ei0 ei2 ei3 ei1 60 59 58 57 56 55 54 53 52 51 50 49 48 47 46 45 44 43 42 41 VSS_1 VDD_1 PA3 (HS) PA2 PA1 PA0 PC7 / SS / AIN15 PC6 / SCK /ICCCLK PH3 PH2 PH1 PH0 PC5 / MOSI / AIN14 PC4 / MISO / ICCDATA PC3 (HS) /ICAP1_B PC2(HS) / ICAP2_B PC1 / OCMP1_B / AIN13 PC0 / OCMP2_B /AIN12 VSS_0 VDD_0 MCO /AIN8 / PF0 BEEP / (HS) PF1 (HS) PF2 OCMP2_A / AIN9 /PF3 OCMP1_A/AIN10 /PF4 ICAP2_A/ AIN11 /PF5 ICAP1_A / (HS) / PF6 EXTCLK_A / (HS) PF7 PG6 PG7 AIN4/PD4 AIN5 / PD5 AIN6 / PD6 AIN7 / PD7 VAREF VSSA VDD3 VSS3 PG4 PG5 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 (HS) PE4 (HS) PE5 (HS) PE6 (HS) PE7 PWM3 / PB0 PWM2 / PB1 PWM1 / PB2 PWM0 / PB3 PG0 PG1 PG2 PG3 ARTCLK / (HS) PB4 ARTIC1 / PB5 ARTIC2 / PB6 PB7 AIN0 / PD0 AIN1 / PD1 AIN2 / PD2 AIN3 / PD3 (HS) 20mA high sink capability eix associated external interrupt vector 8/215 ST72F521, ST72521B PIN DESCRIPTION (Cont'd) PE3 / CANRX PE2 / CANTX PE1 / RDI PE0 / TDO VDD_2 OSC1 OSC2 VSS_2 TLI EVD RESET VPP / ICCSEL PA7 (HS) / SCLI PA6 (HS) / SDAI PA5 (HS) PA4 (HS) Figure 3. 64-Pin TQFP 14x14 and 10x10 Package Pinout AIN2 / PD2 AIN3 / PD3 64 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 48 47 46 45 ei0 44 43 ei2 42 41 40 39 ei3 38 37 36 35 ei1 34 33 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 VSS_1 VDD_1 PA3 (HS) PA2 PA1 PA0 PC7 / SS / AIN15 PC6 / SCK / ICCCLK PC5 / MOSI / AIN14 PC4 / MISO / ICCDATA PC3 (HS) / ICAP1_B PC2 (HS) / ICAP2_B PC1 / OCMP1_B / AIN13 PC0 / OCMP2_B / AIN12 VSS_0 VDD_0 AIN4 / PD4 AIN5 / PD5 AIN6 / PD6 AIN7 / PD7 VAREF VSSA VDD_3 VSS_3 MCO / AIN8 / PF0 BEEP / (HS) PF1 (HS) PF2 OCMP2_A / AIN9 / PF3 OCMP1_A / AIN10 / PF4 ICAP2_A / AIN11 / PF5 ICAP1_A / (HS) PF6 EXTCLK_A / (HS) PF7 (HS) PE4 (HS) PE5 (HS) PE6 (HS) PE7 PWM3 / PB0 PWM2 / PB1 PWM1 / PB2 PWM0 / PB3 ARTCLK / (HS) PB4 ARTIC1 / PB5 ARTIC2 / PB6 PB7 AIN0 / PD0 AIN1 / PD1 (HS) 20mA high sink capability eix associated external interrupt vector 9/215 ST72F521, ST72521B PIN DESCRIPTION (Cont'd) For external pin connection guidelines, refer to See "ELECTRICAL CHARACTERISTICS" on page 165. Legend / Abbreviations for Table 1: Type: I = input, O = output, S = supply Input level: A = Dedicated analog input In/Output level: C = CMOS 0.3VDD/0.7VDD CT= CMOS 0.3VDD/0.7VDD with input trigger TT= TTL 0.8V / 2V with Schmitt trigger Output level: HS = 20mA high sink (on N-buffer only) Port and control configuration: - Input: float = floating, wpu = weak pull-up, int = interrupt 1), ana = analog - Output: OD = open drain 2), PP = push-pull Refer to "I/O PORTS" on page 47 for more details on the software configuration of the I/O ports. The RESET configuration of each pin is shown in bold. This configuration is valid as long as the device is in reset state. Table 1. Device Pin Description 4 PE7 (HS) 5 5 PB0/PWM3 6 6 7 8 PP 4 OD PE6 (HS) HS X X X X Port E4 HS X X X X Port E5 I/O CT I/O CT HS X X X X Port E6 HS X X ana PE5 (HS) 3 I/O CT I/O CT int 2 3 wpu 2 float PE4 (HS) Input Main function Output (after reset) Output 1 Port Input 1 Pin Name Type TQFP64 Level TQFP80 Pin n Alternate function X X Port E7 X ei2 X X Port B0 PWM Output 3 PB1/PWM2 I/O CT I/O CT X ei2 X X Port B1 PWM Output 2 7 PB2/PWM1 I/O CT X ei2 X X Port B2 PWM Output 1 8 PB3/PWM0 I/O CT I/O TT X X X Port B3 PWM Output 0 X X X X Port G0 I/O TT I/O TT X X X X Port G1 X X X X Port G2 I/O TT I/O CT X X X X Port G3 9 - PG0 10 - PG1 11 - PG2 12 - PG3 PB4 (HS)/ARTCLK 13 9 14 10 PB5/ARTIC1 15 X ei3 X X Port B4 PWM-ART External Clock X ei3 X X Port B5 PWM-ART Input Capture 1 11 PB6/ARTIC2 I/O CT I/O CT X ei3 X X Port B6 PWM-ART Input Capture 2 16 12 PB7 I/O CT X X X Port B7 17 13 PD0 /AIN0 I/O CT X X X X X Port D0 ADC Analog Input 0 18 14 PD1/AIN1 I/O CT X X X X X Port D1 ADC Analog Input 1 19 15 PD2/AIN2 X X X X X Port D2 ADC Analog Input 2 20 16 PD3/AIN3 I/O CT I/O CT X X X X X Port D3 ADC Analog Input 3 X X X X Port G6 X X X X Port G7 X X X X Port D4 21 - PG6 22 - PG7 I/O TT I/O TT 17 PD4/AIN4 I/O CT 23 10/215 HS ei2 ei3 X ADC Analog Input 4 ST72F521, ST72521B Pin n Main function Output (after reset) 18 PD5/AIN5 25 19 PD6/AIN6 26 20 PD7/AIN7 27 21 VAREF 28 22 VSSA 23 VDD_3 S S Digital Main Supply Voltage 24 VSS_3 - PG4 S Digital Ground Voltage 29 30 31 32 - PG5 PP X X X X X Port D5 ADC Analog Input 5 X X X X X Port D6 ADC Analog Input 6 I/O CT I X X X X X Port D7 ADC Analog Input 7 ana I/O CT I/O CT int OD Alternate function wpu Input float Output 24 Pin Name Input TQFP64 Port TQFP80 Type Level Analog Reference Voltage for ADC Analog Ground Voltage I/O TT X X X X Port G4 I/O TT X X X X Port G5 X ei1 X X Port F0 Main clock out (fCPU) HS X ei1 X X Port F1 Beep signal output HS X X X Port F2 ADC Analog Input 8 33 25 PF0/MCO/AIN8 I/O CT 34 26 PF1 (HS)/BEEP 35 27 PF2 (HS) I/O CT I/O CT 36 28 PF3/OCMP2_A/AIN9 I/O CT X X X X X Port F3 Timer A OutADC Analog put Compare Input 9 2 37 29 PF4/OCMP1_A/AIN10 I/O CT X X X X X Port F4 Timer A OutADC Analog put Compare Input 10 1 38 30 PF5/ICAP2_A/AIN11 I/O CT X X X X X Port F5 Timer A Input ADC Analog Capture 2 Input 11 39 31 PF6 (HS)/ICAP1_A I/O CT X X X X Port F6 Timer A Input Capture 1 Port F7 Timer A External Clock Source I/O CT HS X ei1 40 32 PF7 (HS)/EXTCLK_A 41 42 33 VDD_0 34 VSS_0 43 35 PC0/OCMP2_B/AIN12 I/O CT X X X X X Port C0 Timer B OutADC Analog put Compare Input 12 2 44 36 PC1/OCMP1_B/AIN13 I/O CT X X X X X Port C1 Timer B OutADC Analog put Compare Input 13 1 HS X X X X S Digital Main Supply Voltage S Digital Ground Voltage 45 37 PC2 (HS)/ICAP2_B I/O CT HS X X X X Port C2 Timer B Input Capture 2 46 38 PC3 (HS)/ICAP1_B I/O CT HS X X X X Port C3 Timer B Input Capture 1 47 39 PC4/MISO/ICCDATA I/O CT X X X X Port C4 SPI Master In ICC Data In/ Slave Out put Data 48 40 PC5/MOSI/AIN14 I/O CT X X X X Port C5 SPI Master ADC Analog Out / Slave In Input 14 Data X 49 - PH0 X X X Port H0 - PH1 I/O TT I/O TT X 50 X X X X Port H1 51 - PH2 I/O TT X X X X Port H2 11/215 ST72F521, ST72521B PP Main function Output (after reset) OD X ana X int Input wpu I/O TT Port float PH3 Output TQFP64 - Type TQFP80 52 Pin Name Input Level Pin n X X Alternate function Port H3 SPI Serial Clock 53 41 PC6/SCK/ICCCLK I/O CT X X 54 42 PC7/SS/AIN15 I/O CT X X 55 43 PA0 X 56 44 PA1 I/O CT I/O CT 57 45 PA2 58 46 PA3 (HS) I/O CT I/O CT 59 60 47 VDD_1 48 VSS_1 61 49 PA4 (HS) 62 HS X X Port C6 X X Port C7 ei0 X X Port A0 X ei0 X X Port A1 X ei0 X X Port A2 X X X X ei0 S Caution: Negative current injection not allowed on this pin5) SPI Slave ADC Analog Select (active Input 15 low) Port A3 Digital Main Supply Voltage S Digital Ground Voltage HS X X X X Port A4 50 PA5 (HS) I/O CT I/O CT HS X X X X Port A5 63 51 PA6 (HS)/SDAI I/O CT HS X T Port A6 I2C Data 1) 64 52 PA7 (HS)/SCLI I/O CT HS X T Port A7 I2C Clock 1) 65 53 VPP/ ICCSEL 66 54 RESET 67 55 EVD 68 56 TLI 69 - PH4 70 - PH5 71 - PH6 72 - PH7 ICC Clock Output Must be tied low. In flash programming mode, this pin acts as the programming voltage input VPP. See Section 12.9.2 for more details. High voltage must not be applied to ROM devices I I/O CT Top priority non maskable interrupt. External voltage detector CT X I/O TT I/O TT I X X X X Port H4 X X X X Port H5 I/O TT I/O TT X X X X Port H6 X X X X Port H7 73 57 VSS_2 74 58 OSC23) I/O 75 59 OSC13) I X Top level interrupt input pin S Digital Ground Voltage Resonator oscillator inverter output External clock input or Resonator oscillator inverter input 76 60 VDD_2 77 61 PE0/TDO I/O CT X X X X Port E0 SCI Transmit Data Out 78 62 PE1/RDI I/O CT X X X X Port E1 SCI Receive Data In 79 63 PE2/CANTX I/O CT Port E2 CAN Transmit Data Output 80 64 PE3/CANRX I/O CT Port E3 CAN Receive Data Input S Digital Main Supply Voltage X X X X X Notes: 1. In the interrupt input column, "eiX" defines the associated external interrupt vector. If the weak pull-up 12/215 ST72F521, ST72521B column (wpu) is merged with the interrupt column (int), then the I/O configuration is pull-up interrupt input, else the configuration is floating interrupt input. 2. In the open drain output column, "T" defines a true open drain I/O (P-Buffer and protection diode to VDD are not implemented). See See "I/O PORTS" on page 47. and Section 12.8 I/O PORT PIN CHARACTERISTICS for more details. 3. OSC1 and OSC2 pins connect a crystal/ceramic resonator, or an external source to the on-chip oscillator; see Section 1 INTRODUCTION and Section 12.5 CLOCK AND TIMING CHARACTERISTICS for more details. 4. On the chip, each I/O port may have up to 8 pads. Pads that are not bonded to external pins are in input pull-up configuration after reset. The configuration of these pads must be kept at reset state to avoid added current consumption. 13/215 ST72F521, ST72521B 3 REGISTER & MEMORY MAP As shown in Figure 4, the MCU is capable of addressing 64K bytes of memories and I/O registers. The available memory locations consist of 128 bytes of register locations, up to 2Kbytes of RAM and up to 60Kbytes of user program memory. The RAM space includes up to 256 bytes for the stack from 0100h to 01FFh. The highest address bytes contain the user reset and interrupt vectors. IMPORTANT: Memory locations marked as "Reserved" must never be accessed. Accessing a reseved area can have unpredictable effects on the device. Related Documentation AN 985: Executing Code in ST7 RAM Figure 4. Memory Map 0000h 007Fh 0080h HW Registers (see Table 2) 087Fh 0880h Reserved 0FFFh 1000h Program Memory (60K or 32K) FFFFh 14/215 Short Addressing RAM (zero page) 00FFh 0100h RAM (2048 or 1024 Bytes) FFDFh FFE0h 0080h Interrupt & Reset Vectors (see Table 7) 256 Bytes Stack 01FFh 0200h or 047Fh or 067Fh or 087Fh 1000h 16-bit Addressing RAM 8000h FFFFh 60 KBytes 32 KBytes ST72F521, ST72521B Table 2. Hardware Register Map Register Label Block 0000h 0001h 0002h Port A PADR PADDR PAOR Port A Data Register Port A Data Direction Register Port A Option Register 00h1) 00h 00h R/W R/W R/W 0003h 0004h 0005h Port B PBDR PBDDR PBOR Port B Data Register Port B Data Direction Register Port B Option Register 00h1) 00h 00h R/W R/W R/W 0006h 0007h 0008h Port C PCDR PCDDR PCOR Port C Data Register Port C Data Direction Register Port C Option Register 00h1) 00h 00h R/W R/W R/W Port D PDDR PDDDR PDOR Port D Data Register Port D Data Direction Register Port D Option Register 00h1) 00h 00h R/W R/W R/W 000Ch 000Dh 000Eh Port E PEDR PEDDR PEOR Port E Data Register Port E Data Direction Register Port E Option Register 00h1) 00h 00h R/W R/W2) R/W2) 000Fh 0010h 0011h Port F PFDR PFDDR PFOR Port F Data Register Port F Data Direction Register Port F Option Register 00h1) 00h 00h R/W R/W R/W 0009h 000Ah 000Bh Register Name Reset Status Address Remarks 0012h 0013h 0014h Port G 2) PGDR PGDDR PGOR Port G Data Register Port G Data Direction Register Port G Option Register 00h1) 00h 00h R/W R/W R/W 0015h 0016h 0017h Port H 2) PHDR PHDDR PHOR Port H Data Register Port H Data Direction Register Port H Option Register 00h1) 00h 00h R/W R/W R/W I2CCR I2CSR1 I2CSR2 I2CCCR I2COAR1 I2COAR2 I2CDR I2C Control Register I2C Status Register 1 I2C Status Register 2 I2C Clock Control Register I2C Own Address Register 1 I2C Own Address Register2 I2C Data Register 0018h 0019h 001Ah 001Bh 001Ch 001Dh 001Eh I2C 001Fh 0020h 0021h 0022h 0023h 00h 00h 00h 00h 00h 00h 00h R/W Read Only Read Only R/W R/W R/W R/W xxh 0xh 00h R/W R/W R/W Reserved Area (2 Bytes) SPI SPIDR SPICR SPICSR SPI Data I/O Register SPI Control Register SPI Control/Status Register 15/215 ST72F521, ST72521B Address 0024h 0025h 0026h 0027h Block ITC 0028h 0029h FLASH 002Ah WATCHDOG 002Bh 002Ch 002Dh MCC Register Label 16/215 Remarks Interrupt Software Priority Register 0 Interrupt Software Priority Register 1 Interrupt Software Priority Register 2 Interrupt Software Priority Register 3 FFh FFh FFh FFh R/W R/W R/W R/W EICR External Interrupt Control Register 00h R/W FCSR Flash Control/Status Register 00h R/W WDGCR Watchdog Control Register 7Fh R/W SICSR System Integrity Control/Status Register MCCSR MCCBCR Main Clock Control / Status Register Main Clock Controller: Beep Control Register 000x 000x b R/W 00h 00h R/W R/W Reserved Area (3 Bytes) TIMER A TACR2 TACR1 TACSR TAIC1HR TAIC1LR TAOC1HR TAOC1LR TACHR TACLR TAACHR TAACLR TAIC2HR TAIC2LR TAOC2HR TAOC2LR 0040h 0041h 0042h 0043h 0044h 0045h 0046h 0047h 0048h 0049h 004Ah 004Bh 004Ch 004Dh 004Eh 004Fh Reset Status ISPR0 ISPR1 ISPR2 ISPR3 002Eh to 0030h 0031h 0032h 0033h 0034h 0035h 0036h 0037h 0038h 0039h 003Ah 003Bh 003Ch 003Dh 003Eh 003Fh Register Name Timer A Control Register 2 Timer A Control Register 1 Timer A Control/Status Register Timer A Input Capture 1 High Register Timer A Input Capture 1 Low Register Timer A Output Compare 1 High Register Timer A Output Compare 1 Low Register Timer A Counter High Register Timer A Counter Low Register Timer A Alternate Counter High Register Timer A Alternate Counter Low Register Timer A Input Capture 2 High Register Timer A Input Capture 2 Low Register Timer A Output Compare 2 High Register Timer A Output Compare 2 Low Register 00h 00h xxxx x0xx b xxh xxh 80h 00h FFh FCh FFh FCh xxh xxh 80h 00h R/W R/W R/W Read Only Read Only R/W R/W Read Only Read Only Read Only Read Only Read Only Read Only R/W R/W 00h 00h xxxx x0xx b xxh xxh 80h 00h FFh FCh FFh FCh xxh xxh 80h 00h R/W R/W R/W Read Only Read Only R/W R/W Read Only Read Only Read Only Read Only Read Only Read Only R/W R/W Reserved Area (1 Byte) TIMER B TBCR2 TBCR1 TBCSR TBIC1HR TBIC1LR TBOC1HR TBOC1LR TBCHR TBCLR TBACHR TBACLR TBIC2HR TBIC2LR TBOC2HR TBOC2LR Timer B Control Register 2 Timer B Control Register 1 Timer B Control/Status Register Timer B Input Capture 1 High Register Timer B Input Capture 1 Low Register Timer B Output Compare 1 High Register Timer B Output Compare 1 Low Register Timer B Counter High Register Timer B Counter Low Register Timer B Alternate Counter High Register Timer B Alternate Counter Low Register Timer B Input Capture 2 High Register Timer B Input Capture 2 Low Register Timer B Output Compare 2 High Register Timer B Output Compare 2 Low Register ST72F521, ST72521B Address 0050h 0051h 0052h 0053h 0054h 0055h 0056h 0057h Block SCI Register Label SCISR SCIDR SCIBRR SCICR1 SCICR2 SCIERPR SCIETPR 0058h 0059h CAN 0070h 0071h 0072h ADC 0073h 0074h 0075h 0076h 0077h 007Bh 007Ch 007Dh SCI Status Register SCI Data Register SCI Baud Rate Register SCI Control Register 1 SCI Control Register 2 SCI Extended Receive Prescaler Register Reserved area SCI Extended Transmit Prescaler Register Reset Status Remarks C0h xxh 00h x000 0000b 00h 00h --00h Read Only R/W R/W R/W R/W R/W R/W Reserved Area (2 Bytes) 005Ah 005Bh 005Ch 005Dh 005Eh 005Fh 0060h to 006Fh 0078h 0079h 007Ah Register Name PWM ART CANISR CANICR CANCSR CANBRPR CANBTR CANPSR CAN Interrupt Status Register CAN Interrupt Control Register CAN Control / Status Register CAN Baud Rate Prescaler Register CAN Bit Timing Register CAN Page Selection Register First address to Last address of CAN page x 00h 00h 00h 00h 23h 00h -- R/W R/W R/W R/W R/W R/W See CAN Description ADCCSR ADCDRH ADCDRL Control/Status Register Data High Register Data Low Register 00h 00h 00h R/W Read Only Read Only PWMDCR3 PWMDCR2 PWMDCR1 PWMDCR0 PWMCR ARTCSR ARTCAR ARTARR ARTICCSR ARTICR1 ARTICR2 PWM AR Timer Duty Cycle Register 3 PWM AR Timer Duty Cycle Register 2 PWM AR Timer Duty Cycle Register 1 PWM AR Timer Duty Cycle Register 0 PWM AR Timer Control Register Auto-Reload Timer Control/Status Register Auto-Reload Timer Counter Access Register Auto-Reload Timer Auto-Reload Register AR Timer Input Capture Control/Status Reg. AR Timer Input Capture Register 1 AR Timer Input Capture Register 1 00h 00h 00h 00h 00h 00h 00h 00h R/W R/W R/W R/W R/W R/W R/W R/W R/W Read Only Read Only 007Eh 007Fh 00h 00h 00h Reserved Area (2 Bytes) Legend: x=undefined, R/W=read/write Notes: 1. The contents of the I/O port DR registers are readable only in output configuration. In input configuration, the values of the I/O pins are returned instead of the DR register contents. 2. The bits associated with unavailable pins must always keep their reset value. 17/215 ST72F521, ST72521B 4 FLASH PROGRAM MEMORY 4.1 Introduction The ST7 dual voltage High Density Flash (HDFlash) is a non-volatile memory that can be electrically erased as a single block or by individual sectors and programmed on a Byte-by-Byte basis using an external VPP supply. The HDFlash devices can be programmed and erased off-board (plugged in a programming tool) or on-board using ICP (In-Circuit Programming) or IAP (In-Application Programming). The array matrix organisation allows each sector to be erased and reprogrammed without affecting other sectors. sectors (see Table 3). Each of these sectors can be erased independently to avoid unnecessary erasing of the whole Flash memory when only a partial erasing is required. The first two sectors have a fixed size of 4 Kbytes (see Figure 5). They are mapped in the upper part of the ST7 addressing space so the reset and interrupt vectors are located in Sector 0 (F000hFFFFh). Table 3. Sectors available in Flash devices Flash Size (bytes) 4.2 Main Features Three Flash programming modes: - Insertion in a programming tool. In this mode, all sectors including option bytes can be programmed or erased. - ICP (In-Circuit Programming). In this mode, all sectors including option bytes can be programmed or erased without removing the device from the application board. - IAP (In-Application Programming) In this mode, all sectors except Sector 0, can be programmed or erased without removing the device from the application board and while the application is running. ICT (In-Circuit Testing) for downloading and executing user application test patterns in RAM Read-out protection Register Access Security System (RASS) to prevent accidental programming or erasing 4.3 Structure The Flash memory is organised in sectors and can be used for both code and data storage. Depending on the overall Flash memory size in the microcontroller device, there are up to three user Available Sectors 4K Sector 0 8K Sectors 0,1 > 8K Sectors 0,1, 2 4.3.1 Read-out Protection Read-out protection, when selected, provides a protection against Program Memory content extraction and against write access to Flash memory. Even if no protection can be considered as totally unbreakable, the feature provides a very high level of protection for a general purpose microcontroller. In flash devices, this protection is removed by reprogramming the option. In this case, the entire program memory is first automatically erased and the device can be reprogrammed. Read-out protection selection depends on the device type: - In Flash devices it is enabled and removed through the FMP_R bit in the option byte. - In ROM devices it is enabled by mask option specified in the Option List. Note: In flash devices, the LVD is not supported if read-out protection is enabled. Figure 5. Memory Map and Sector Address 4K 8K 10K 16K 24K 32K 48K 60K 1000h FLASH MEMORY SIZE 3FFFh 7FFFh 9FFFh SECTOR 2 BFFFh D7FFh DFFFh EFFFh FFFFh 18/215 2 Kbytes 8 Kbytes 16 Kbytes 24 Kbytes 40 Kbytes 52 Kbytes 4 Kbytes 4 Kbytes SECTOR 1 SECTOR 0 ST72F521, ST72521B FLASH PROGRAM MEMORY (Cont'd) - - - - ICCCLK: ICC output serial clock pin ICCDATA: ICC input/output serial data pin ICCSEL/VPP: programming voltage OSC1(or OSCIN): main clock input for external source (optional) - VDD: application board power supply (optional, see Figure 6, Note 3) 4.4 ICC Interface ICC needs a minimum of 4 and up to 6 pins to be connected to the programming tool (see Figure 6). These pins are: - RESET: device reset - VSS: device power supply ground Figure 6. Typical ICC Interface PROGRAMMING TOOL ICC CONNECTOR ICC Cable APPLICATION BOARD (See Note 3) ICC CONNECTOR HE10 CONNECTOR TYPE OPTIONAL (See Note 4) 9 7 5 3 1 10 8 6 4 2 APPLICATION RESET SOURCE See Note 2 10k Notes: 1. If the ICCCLK or ICCDATA pins are only used as outputs in the application, no signal isolation is necessary. As soon as the Programming Tool is plugged to the board, even if an ICC session is not in progress, the ICCCLK and ICCDATA pins are not available for the application. If they are used as inputs by the application, isolation such as a serial resistor has to implemented in case another device forces the signal. Refer to the Programming Tool documentation for recommended resistor values. 2. During the ICC session, the programming tool must control the RESET pin. This can lead to conflicts between the programming tool and the application reset circuit if it drives more than 5mA at high level (push pull output or pull-up resistor<1K). A schottky diode can be used to isolate the application RESET circuit in this case. When using a classical RC network with R>1K or a reset man- ICCDATA ICCCLK ST7 RESET See Note 1 ICCSEL/VPP OSC1 CL1 OSC2 VDD CL2 VSS APPLICATION POWER SUPPLY APPLICATION I/O agement IC with open drain output and pull-up resistor>1K, no additional components are needed. In all cases the user must ensure that no external reset is generated by the application during the ICC session. 3. The use of Pin 7 of the ICC connector depends on the Programming Tool architecture. This pin must be connected when using most ST Programming Tools (it is used to monitor the application power supply). Please refer to the Programming Tool manual. 4. Pin 9 has to be connected to the OSC1 or OSCIN pin of the ST7 when the clock is not available in the application or if the selected clock option is not programmed in the option byte. ST7 devices with multi-oscillator capability need to have OSC2 grounded in this case. 19/215 ST72F521, ST72521B FLASH PROGRAM MEMORY (Cont'd) 4.5 ICP (In-Circuit Programming) To perform ICP the microcontroller must be switched to ICC (In-Circuit Communication) mode by an external controller or programming tool. Depending on the ICP code downloaded in RAM, Flash memory programming can be fully customized (number of bytes to program, program locations, or selection serial communication interface for downloading). When using an STMicroelectronics or third-party programming tool that supports ICP and the specific microcontroller device, the user needs only to implement the ICP hardware interface on the application board (see Figure 6). For more details on the pin locations, refer to the device pinout description. 4.6 IAP (In-Application Programming) This mode uses a BootLoader program previously stored in Sector 0 by the user (in ICP mode or by plugging the device in a programming tool). This mode is fully controlled by user software. This allows it to be adapted to the user application, (user-defined strategy for entering programming mode, choice of communications protocol used to fetch the data to be stored, etc.). For example, it is possible to download code from the SPI, SCI, USB or CAN interface and program it in the Flash. IAP mode can be used to program any of the Flash sectors except Sector 0, which is write/erase protected to allow recovery in case errors occur during the programming operation. 4.7 Related Documentation For details on Flash programming and ICC protocol, refer to the ST7 Flash Programming Reference Manual and to the ST7 ICC Protocol Reference Manual. 4.7.1 Register Description FLASH CONTROL/STATUS REGISTER (FCSR) Read/Write Reset Value: 0000 0000 (00h) 7 0 0 0 0 0 0 0 0 0 This register is reserved for use by Programming Tool software. It controls the Flash programming and erasing operations. Figure 7. Flash Control/Status Register Address and Reset Value Address (Hex.) Register Label 0029h FCSR Reset Value 20/215 7 6 5 4 3 2 1 0 0 0 0 0 0 0 0 0 ST72F521, ST72521B 5 CENTRAL PROCESSING UNIT 5.1 INTRODUCTION 5.3 CPU REGISTERS This CPU has a full 8-bit architecture and contains six internal registers allowing efficient 8-bit data manipulation. The 6 CPU registers shown in Figure 8 are not present in the memory mapping and are accessed by specific instructions. Accumulator (A) The Accumulator is an 8-bit general purpose register used to hold operands and the results of the arithmetic and logic calculations and to manipulate data. Index Registers (X and Y) These 8-bit registers are used to create effective addresses or as temporary storage areas for data manipulation. (The Cross-Assembler generates a precede instruction (PRE) to indicate that the following instruction refers to the Y register.) The Y register is not affected by the interrupt automatic procedures. Program Counter (PC) The program counter is a 16-bit register containing the address of the next instruction to be executed by the CPU. It is made of two 8-bit registers PCL (Program Counter Low which is the LSB) and PCH (Program Counter High which is the MSB). 5.2 MAIN FEATURES Enable executing 63 basic instructions Fast 8-bit by 8-bit multiply 17 main addressing modes (with indirect addressing mode) Two 8-bit index registers 16-bit stack pointer Low power HALT and WAIT modes Priority maskable hardware interrupts Non-maskable software/hardware interrupts Figure 8. CPU Registers 7 0 ACCUMULATOR RESET VALUE = XXh 7 0 X INDEX REGISTER RESET VALUE = XXh 7 0 Y INDEX REGISTER RESET VALUE = XXh 15 PCH 8 7 PCL 0 PROGRAM COUNTER RESET VALUE = RESET VECTOR @ FFFEh-FFFFh 7 0 1 1 I1 H I0 N Z C CONDITION CODE REGISTER RESET VALUE = 1 1 1 X 1 X X X 15 8 7 0 STACK POINTER RESET VALUE = STACK HIGHER ADDRESS X = Undefined Value 21/215 ST72F521, ST72521B CENTRAL PROCESSING UNIT (Cont'd) Condition Code Register (CC) Read/Write Reset Value: 111x1xxx Bit 1 = Z Zero. 7 1 0 1 I1 H I0 N Z C The 8-bit Condition Code register contains the interrupt masks and four flags representative of the result of the instruction just executed. This register can also be handled by the PUSH and POP instructions. These bits can be individually tested and/or controlled by specific instructions. Arithmetic Management Bits Bit 4 = H Half carry. This bit is set by hardware when a carry occurs between bits 3 and 4 of the ALU during an ADD or ADC instructions. It is reset by hardware during the same instructions. 0: No half carry has occurred. 1: A half carry has occurred. This bit is tested using the JRH or JRNH instruction. The H bit is useful in BCD arithmetic subroutines. Bit 2 = N Negative. This bit is set and cleared by hardware. It is representative of the result sign of the last arithmetic, logical or data manipulation. It's a copy of the result 7th bit. 0: The result of the last operation is positive or null. 1: The result of the last operation is negative (i.e. the most significant bit is a logic 1). This bit is accessed by the JRMI and JRPL instructions. 22/215 This bit is set and cleared by hardware. This bit indicates that the result of the last arithmetic, logical or data manipulation is zero. 0: The result of the last operation is different from zero. 1: The result of the last operation is zero. This bit is accessed by the JREQ and JRNE test instructions. Bit 0 = C Carry/borrow. This bit is set and cleared by hardware and software. It indicates an overflow or an underflow has occurred during the last arithmetic operation. 0: No overflow or underflow has occurred. 1: An overflow or underflow has occurred. This bit is driven by the SCF and RCF instructions and tested by the JRC and JRNC instructions. It is also affected by the "bit test and branch", shift and rotate instructions. Interrupt Management Bits Bit 5,3 = I1, I0 Interrupt The combination of the I1 and I0 bits gives the current interrupt software priority. Interrupt Software Priority Level 0 (main) Level 1 Level 2 Level 3 (= interrupt disable) I1 1 0 0 1 I0 0 1 0 1 These two bits are set/cleared by hardware when entering in interrupt. The loaded value is given by the corresponding bits in the interrupt software priority registers (IxSPR). They can be also set/ cleared by software with the RIM, SIM, IRET, HALT, WFI and PUSH/POP instructions. See the interrupt management chapter for more details. ST72F521, ST72521B CENTRAL PROCESSING UNIT (Cont'd) Stack Pointer (SP) Read/Write Reset Value: 01 FFh 15 0 8 0 0 0 0 0 0 7 SP7 1 0 SP6 SP5 SP4 SP3 SP2 SP1 SP0 The Stack Pointer is a 16-bit register which is always pointing to the next free location in the stack. It is then decremented after data has been pushed onto the stack and incremented before data is popped from the stack (see Figure 9). Since the stack is 256 bytes deep, the 8 most significant bits are forced by hardware. Following an MCU Reset, or after a Reset Stack Pointer instruction (RSP), the Stack Pointer contains its reset value (the SP7 to SP0 bits are set) which is the stack higher address. The least significant byte of the Stack Pointer (called S) can be directly accessed by a LD instruction. Note: When the lower limit is exceeded, the Stack Pointer wraps around to the stack upper limit, without indicating the stack overflow. The previously stored information is then overwritten and therefore lost. The stack also wraps in case of an underflow. The stack is used to save the return address during a subroutine call and the CPU context during an interrupt. The user may also directly manipulate the stack by means of the PUSH and POP instructions. In the case of an interrupt, the PCL is stored at the first location pointed to by the SP. Then the other registers are stored in the next locations as shown in Figure 9. - When an interrupt is received, the SP is decremented and the context is pushed on the stack. - On return from interrupt, the SP is incremented and the context is popped from the stack. A subroutine call occupies two locations and an interrupt five locations in the stack area. Figure 9. Stack Manipulation Example CALL Subroutine PUSH Y Interrupt Event POP Y RET or RSP IRET @ 0100h SP SP CC A SP CC A X X X PCH PCH PCH PCL PCL PCL PCH PCH PCH PCH PCH PCL PCL PCL PCL PCL SP @ 01FFh Y CC A SP SP Stack Higher Address = 01FFh Stack Lower Address = 0100h 23/215 ST72F521, ST72521B 6 SUPPLY, RESET AND CLOCK MANAGEMENT 6.1 PHASE LOCKED LOOP The device includes a range of utility features for securing the application in critical situations (for example in case of a power brown-out), and reducing the number of external components. An overview is shown in Figure 11. For more details, refer to dedicated parametric section. If the clock frequency input to the PLL is in the range 2 to 4 MHz, the PLL can be used to multiply the frequency by two to obtain an fOSC2 of 4 to 8 MHz. The PLL is enabled by option byte. If the PLL is disabled, then fOSC2 = fOSC/2. Caution: The PLL is not recommended for applications where timing accuracy is required. See "PLL Characteristics" on page 177. Main features Optional PLL for multiplying the frequency by 2 (not to be used with internal RC oscillator) Reset Sequence Manager (RSM) Multi-Oscillator Clock Management (MO) - 5 Crystal/Ceramic resonator oscillators - 1 Internal RC oscillator System Integrity Management (SI) - Main supply Low voltage detection (LVD) - Auxiliary Voltage detector (AVD) with interrupt capability for monitoring the main supply or the EVD pin Figure 10. PLL Block Diagram PLL x 2 0 /2 1 fOSC fOSC2 PLL OPTION BIT Figure 11. Clock, Reset and Supply Block Diagram OSC2 MULTI- OSC1 fOSC2 fOSC OSCILLATOR (MO) PLL (option) MAIN CLOCK fCPU CONTROLLER WITH REALTIME CLOCK (MCC/RTC) SYSTEM INTEGRITY MANAGEMENT RESET SEQUENCE RESET MANAGER (RSM) WATCHDOG AVD Interrupt Request SICSR AVD AVD AVD LVD S IE F RF TIMER (WDG) 0 0 0 LOW VOLTAGE VSS DETECTOR VDD (LVD) 0 EVD 24/215 AUXILIARY VOLTAGE DETECTOR 1 (AVD) WDG RF ST72F521, ST72521B 6.2 MULTI-OSCILLATOR (MO) Table 4. ST7 Clock Sources External Clock Hardware Configuration Crystal/Ceramic Resonators External Clock Source In this external clock mode, a clock signal (square, sinus or triangle) with ~50% duty cycle has to drive the OSC1 pin while the OSC2 pin is tied to ground. Crystal/Ceramic Oscillators This family of oscillators has the advantage of producing a very accurate rate on the main clock of the ST7. The selection within a list of 4 oscillators with different frequency ranges has to be done by option byte in order to reduce consumption (refer to section 14.1 on page 201 for more details on the frequency ranges). In this mode of the multi-oscillator, the resonator and the load capacitors have to be placed as close as possible to the oscillator pins in order to minimize output distortion and start-up stabilization time. The loading capacitance values must be adjusted according to the selected oscillator. These oscillators are not stopped during the RESET phase to avoid losing time in the oscillator start-up phase. Internal RC Oscillator This oscillator allows a low cost solution for the main clock of the ST7 using only an internal resistor and capacitor. Internal RC oscillator mode has the drawback of a lower frequency accuracy and should not be used in applications that require accurate timing. In this mode, the two oscillator pins have to be tied to ground. Internal RC Oscillator The main clock of the ST7 can be generated by three different source types coming from the multioscillator block: an external source 4 crystal or ceramic resonator oscillators an internal high frequency RC oscillator Each oscillator is optimized for a given frequency range in terms of consumption and is selectable through the option byte. The associated hardware configurations are shown in Table 4. Refer to the electrical characteristics section for more details. Caution: The OSC1 and/or OSC2 pins must not be left unconnected. For the purposes of Failure Mode and Effect Analysis, it should be noted that if the OSC1 and/or OSC2 pins are left unconnected, the ST7 main oscillator may start and, in this configuration, could generate an fOSC clock frequency in excess of the allowed maximum (>16MHz.), putting the ST7 in an unsafe/undefined state. The product behaviour must therefore be considered undefined when the OSC pins are left unconnected. ST7 OSC1 OSC2 EXTERNAL SOURCE ST7 OSC1 CL1 OSC2 LOAD CAPACITORS CL2 ST7 OSC1 OSC2 25/215 ST72F521, ST72521B 6.3 RESET SEQUENCE MANAGER (RSM) 6.3.1 Introduction The reset sequence manager includes three RESET sources as shown in Figure 13: External RESET source pulse Internal LVD RESET (Low Voltage Detection) Internal WATCHDOG RESET These sources act on the RESET pin and it is always kept low during the delay phase. The RESET service routine vector is fixed at addresses FFFEh-FFFFh in the ST7 memory map. The basic RESET sequence consists of 3 phases as shown in Figure 12: Active Phase depending on the RESET source 256 or 4096 CPU clock cycle delay (selected by option byte) RESET vector fetch The 256 or 4096 CPU clock cycle delay allows the oscillator to stabilise and ensures that recovery has taken place from the Reset state. The shorter or longer clock cycle delay should be selected by option byte to correspond to the stabilization time of the external oscillator used in the application (see section 14.1 on page 201). The RESET vector fetch phase duration is 2 clock cycles. Figure 12. RESET Sequence Phases RESET Active Phase INTERNAL RESET 256 or 4096 CLOCK CYCLES FETCH VECTOR 6.3.2 Asynchronous External RESET pin The RESET pin is both an input and an open-drain output with integrated RON weak pull-up resistor. This pull-up has no fixed value but varies in accordance with the input voltage. It can be pulled low by external circuitry to reset the device. See "CONTROL PIN CHARACTERISTICS" on page 185 for more details. A RESET signal originating from an external source must have a duration of at least th(RSTL)in in order to be recognized (see Figure 14). This detection is asynchronous and therefore the MCU can enter reset state even in HALT mode. Figure 13. Reset Block Diagram VDD RON RESET INTERNAL RESET Filter PULSE GENERATOR 26/215 WATCHDOG RESET LVD RESET ST72F521, ST72521B RESET SEQUENCE MANAGER (Cont'd) The RESET pin is an asynchronous signal which plays a major role in EMS performance. In a noisy environment, it is recommended to follow the guidelines mentioned in the electrical characteristics section. If the external RESET pulse is shorter than tw(RSTL)out (see short ext. Reset in Figure 14), the signal on the RESET pin may be stretched. Otherwise the delay will not be applied (see long ext. Reset in Figure 14). Starting from the external RESET pulse recognition, the device RESET pin acts as an output that is pulled low during at least tw(RSTL)out. 6.3.3 External Power-On RESET If the LVD is disabled by option byte, to start up the microcontroller correctly, the user must ensure by means of an external reset circuit that the reset signal is held low until VDD is over the minimum level specified for the selected fOSC frequency. (see "OPERATING CONDITIONS" on page 167) A proper reset signal for a slow rising VDD supply can generally be provided by an external RC network connected to the RESET pin. 6.3.4 Internal Low Voltage Detector (LVD) RESET Two different RESET sequences caused by the internal LVD circuitry can be distinguished: Power-On RESET Voltage Drop RESET The device RESET pin acts as an output that is pulled low when VDD<VIT+ (rising edge) or VDD<VIT- (falling edge) as shown in Figure 14. The LVD filters spikes on VDD larger than tg(VDD) to avoid parasitic resets. 6.3.5 Internal Watchdog RESET The RESET sequence generated by a internal Watchdog counter overflow is shown in Figure 14. Starting from the Watchdog counter underflow, the device RESET pin acts as an output that is pulled low during at least tw(RSTL)out. Figure 14. RESET Sequences VDD VIT+(LVD) VIT-(LVD) LVD RESET RUN SHORT EXT. RESET RUN ACTIVE PHASE tw(RSTL)out th(RSTL)in LONG EXT. RESET RUN ACTIVE PHASE ACTIVE PHASE WATCHDOG RESET RUN ACTIVE PHASE RUN tw(RSTL)out tw(RSTL)out th(RSTL)in DELAY EXTERNAL RESET SOURCE RESET PIN WATCHDOG RESET WATCHDOG UNDERFLOW INTERNAL RESET (256 or 4096 TCPU) VECTOR FETCH 27/215 ST72F521, ST72521B 6.4 SYSTEM INTEGRITY MANAGEMENT (SI) The System Integrity Management block contains the Low Voltage Detector (LVD) and Auxiliary Voltage Detector (AVD) functions. It is managed by the SICSR register. 6.4.1 Low Voltage Detector (LVD) The Low Voltage Detector function (LVD) generates a static reset when the VDD supply voltage is below a VIT- reference value. This means that it secures the power-up as well as the power-down keeping the ST7 in reset. The VIT- reference value for a voltage drop is lower than the VIT+ reference value for power-on in order to avoid a parasitic reset when the MCU starts running and sinks current on the supply (hysteresis). The LVD Reset circuitry generates a reset when VDD is below: - VIT+ when VDD is rising - VIT- when VDD is falling The LVD function is illustrated in Figure 15. The voltage threshold can be configured by option byte to be low, medium or high. - under full software control - in static safe reset In these conditions, secure operation is always ensured for the application without the need for external reset hardware. During a Low Voltage Detector Reset, the RESET pin is held low, thus permitting the MCU to reset other devices. Notes: The LVD allows the device to be used without any external RESET circuitry. If the medium or low thresholds are selected, the detection may occur outside the specified operating voltage range. Below 3.8V, device operation is not guaranteed. The LVD is an optional function which can be selected by option byte. It is recommended to make sure that the VDD supply voltage rises monotonously when the device is exiting from Reset, to ensure the application functions properly. Provided the minimum VDD value (guaranteed for the oscillator frequency) is above VIT-, the MCU can only be in two modes: Figure 15. Low Voltage Detector vs Reset VDD Vhys VIT+ VIT- RESET 28/215 ST72F521, ST72521B SYSTEM INTEGRITY MANAGEMENT (Cont'd) 6.4.2 Auxiliary Voltage Detector (AVD) The Voltage Detector function (AVD) is based on an analog comparison between a VIT-(AVD) and VIT+(AVD) reference value and the VDD main supply or the external EVD pin voltage level (VEVD). The VIT- reference value for falling voltage is lower than the VIT+ reference value for rising voltage in order to avoid parasitic detection (hysteresis). The output of the AVD comparator is directly readable by the application software through a real time status bit (AVDF) in the SICSR register. This bit is read only. Caution: The AVD function is active only if the LVD is enabled through the option byte. 6.4.2.1 Monitoring the VDD Main Supply This mode is selected by clearing the AVDS bit in the SICSR register. The AVD voltage threshold value is relative to the selected LVD threshold configured by option byte (see section 14.1 on page 201). If the AVD interrupt is enabled, an interrupt is generated when the voltage crosses the VIT+(AVD) or VIT-(AVD) threshold (AVDF bit toggles). In the case of a drop in voltage, the AVD interrupt acts as an early warning, allowing software to shut down safely before the LVD resets the microcontroller. See Figure 16. The interrupt on the rising edge is used to inform the application that the VDD warning state is over. If the voltage rise time trv is less than 256 or 4096 CPU cycles (depending on the reset delay selected by option byte), no AVD interrupt will be generated when VIT+(AVD) is reached. If trv is greater than 256 or 4096 cycles then: - If the AVD interrupt is enabled before the VIT+(AVD) threshold is reached, then 2 AVD interrupts will be received: the first when the AVDIE bit is set, and the second when the threshold is reached. - If the AVD interrupt is enabled after the VIT+(AVD) threshold is reached then only one AVD interrupt will occur. Figure 16. Using the AVD to Monitor VDD (AVDS bit=0) VDD Early Warning Interrupt (Power has dropped, MCU not not yet in reset) Vhyst VIT+(AVD) VIT-(AVD) VIT+(LVD) VIT-(LVD) AVDF bit trv VOLTAGE RISE TIME 0 1 RESET VALUE 1 0 AVD INTERRUPT REQUEST IF AVDIE bit = 1 INTERRUPT PROCESS INTERRUPT PROCESS LVD RESET 29/215 ST72F521, ST72521B SYSTEM INTEGRITY MANAGEMENT (Cont'd) 6.4.2.2 Monitoring a Voltage on the EVD pin This mode is selected by setting the AVDS bit in the SICSR register. The AVD circuitry can generate an interrupt when the AVDIE bit of the SICSR register is set. This interrupt is generated on the rising and falling edges of the comparator output. This means it is generated when either one of these two events occur: - VEVD rises up to VIT+(EVD) - VEVD falls down to VIT-(EVD) The EVD function is illustrated in Figure 17. For more details, refer to the Electrical Characteristics section. Figure 17. Using the Voltage Detector to Monitor the EVD pin (AVDS bit=1) VEVD Vhyst VIT+(EVD) VIT-(EVD) AVDF 0 1 0 AVD INTERRUPT REQUEST IF AVDIE = 1 INTERRUPT PROCESS 30/215 INTERRUPT PROCESS ST72F521, ST72521B SYSTEM INTEGRITY MANAGEMENT (Cont'd) 6.4.3 Low Power Modes Mode WAIT HALT set and the interrupt mask in the CC register is reset (RIM instruction). Description No effect on SI. AVD interrupts cause the device to exit from Wait mode. The CRSR register is frozen. Interrupt Event AVD event Enable Event Control Flag Bit Exit from Wait Exit from Halt AVDF Yes No AVDIE 6.4.3.1 Interrupts The AVD interrupt event generates an interrupt if the corresponding Enable Control Bit (AVDIE) is 31/215 ST72F521, ST72521B SYSTEM INTEGRITY MANAGEMENT (Cont'd) 6.4.4 Register Description SYSTEM INTEGRITY (SI) CONTROL/STATUS REGISTER (SICSR) Read/Write ed by the LVD block. It is set by hardware (LVD reset) and cleared by software (writing zero). See Reset Value: 000x 000x (00h) WDGRF flag description for more details. When the LVD is disabled by OPTION BYTE, the LVDRF 7 0 bit value is undefined. AVD S AVD IE AVD F LVD RF 0 0 0 WDG RF Bit 7 = AVDS Voltage Detection selection This bit is set and cleared by software. Voltage Detection is available only if the LVD is enabled by option byte. 0: Voltage detection on VDD supply 1: Voltage detection on EVD pin Bit 6 = AVDIE Voltage Detector interrupt enable This bit is set and cleared by software. It enables an interrupt to be generated when the AVDF flag changes (toggles). The pending interrupt information is automatically cleared when software enters the AVD interrupt routine. 0: AVD interrupt disabled 1: AVD interrupt enabled Bit 5 = AVDF Voltage Detector flag This read-only bit is set and cleared by hardware. If the AVDIE bit is set, an interrupt request is generated when the AVDF bit changes value. Refer to Figure 16 and to Section 6.4.2.1 for additional details. 0: VDD or VEVD over VIT+(AVD) threshold 1: VDD or VEVD under VIT-(AVD) threshold Bit 4 = LVDRF LVD reset flag This bit indicates that the last Reset was generat- 32/215 Bits 3:1 = Reserved, must be kept cleared. Bit 0 = WDGRF Watchdog reset flag This bit indicates that the last Reset was generated by the Watchdog peripheral. It is set by hardware (watchdog reset) and cleared by software (writing zero) or an LVD Reset (to ensure a stable cleared state of the WDGRF flag when CPU starts). Combined with the LVDRF flag information, the flag description is given by the following table. RESET Sources LVDRF WDGRF External RESET pin Watchdog LVD 0 0 1 0 1 X Application notes The LVDRF flag is not cleared when another RESET type occurs (external or watchdog), the LVDRF flag remains set to keep trace of the original failure. In this case, a watchdog reset can be detected by software while an external reset can not. CAUTION: When the LVD is not activated with the associated option byte, the WDGRF flag can not be used in the application. ST72F521, ST72521B 7 INTERRUPTS 7.1 INTRODUCTION The ST7 enhanced interrupt management provides the following features: Hardware interrupts Software interrupt (TRAP) Nested or concurrent interrupt management with flexible interrupt priority and level management: - Up to 4 software programmable nesting levels - Up to 16 interrupt vectors fixed by hardware - 2 non maskable events: RESET, TRAP - 1 maskable Top Level event: TLI This interrupt management is based on: - Bit 5 and bit 3 of the CPU CC register (I1:0), - Interrupt software priority registers (ISPRx), - Fixed interrupt vector addresses located at the high addresses of the memory map (FFE0h to FFFFh) sorted by hardware priority order. This enhanced interrupt controller guarantees full upward compatibility with the standard (not nested) ST7 interrupt controller. each interrupt vector (see Table 5). The processing flow is shown in Figure 18 When an interrupt request has to be serviced: - Normal processing is suspended at the end of the current instruction execution. - The PC, X, A and CC registers are saved onto the stack. - I1 and I0 bits of CC register are set according to the corresponding values in the ISPRx registers of the serviced interrupt vector. - The PC is then loaded with the interrupt vector of the interrupt to service and the first instruction of the interrupt service routine is fetched (refer to "Interrupt Mapping" table for vector addresses). The interrupt service routine should end with the IRET instruction which causes the contents of the saved registers to be recovered from the stack. Note: As a consequence of the IRET instruction, the I1 and I0 bits will be restored from the stack and the program in the previous level will resume. Table 5. Interrupt Software Priority Levels Interrupt software priority Level 0 (main) Level 1 Level 2 Level 3 (= interrupt disable) 7.2 MASKING AND PROCESSING FLOW The interrupt masking is managed by the I1 and I0 bits of the CC register and the ISPRx registers which give the interrupt software priority level of Level Low I1 1 0 0 1 High I0 0 1 0 1 Figure 18. Interrupt Processing Flowchart N FETCH NEXT INSTRUCTION Y "IRET" N RESTORE PC, X, A, CC FROM STACK EXECUTE INSTRUCTION Y TRAP Interrupt has the same or a lower software priority than current one THE INTERRUPT STAYS PENDING Y N I1:0 Interrupt has a higher software priority than current one PENDING INTERRUPT RESET STACK PC, X, A, CC LOAD I1:0 FROM INTERRUPT SW REG. LOAD PC FROM INTERRUPT VECTOR 33/215 ST72F521, ST72521B INTERRUPTS (Cont'd) Servicing Pending Interrupts As several interrupts can be pending at the same time, the interrupt to be taken into account is determined by the following two-step process: - the highest software priority interrupt is serviced, - if several interrupts have the same software priority then the interrupt with the highest hardware priority is serviced first. Figure 19 describes this decision process. Figure 19. Priority Decision Process PENDING INTERRUPTS Same SOFTWARE PRIORITY Different HIGHEST SOFTWARE PRIORITY SERVICED HIGHEST HARDWARE PRIORITY SERVICED When an interrupt request is not serviced immediately, it is latched and then processed when its software priority combined with the hardware priority becomes the highest one. Note 1: The hardware priority is exclusive while the software one is not. This allows the previous process to succeed with only one interrupt. Note 2: TLI, RESET and TRAP can be considered as having the highest software priority in the decision process. Different Interrupt Vector Sources Two interrupt source types are managed by the ST7 interrupt controller: the non-maskable type (RESET, TRAP) and the maskable type (external or from internal peripherals). Non-Maskable Sources These sources are processed regardless of the state of the I1 and I0 bits of the CC register (see Figure 18). After stacking the PC, X, A and CC registers (except for RESET), the corresponding vector is loaded in the PC register and the I1 and I0 bits of the CC are set to disable interrupts (level 3). These sources allow the processor to exit HALT mode. 34/215 TRAP (Non Maskable Software Interrupt) This software interrupt is serviced when the TRAP instruction is executed. It will be serviced according to the flowchart in Figure 18. Caution: TRAP can be interrupted by a TLI. RESET The RESET source has the highest priority in the ST7. This means that the first current routine has the highest software priority (level 3) and the highest hardware priority. See the RESET chapter for more details. Maskable Sources Maskable interrupt vector sources can be serviced if the corresponding interrupt is enabled and if its own interrupt software priority (in ISPRx registers) is higher than the one currently being serviced (I1 and I0 in CC register). If any of these two conditions is false, the interrupt is latched and thus remains pending. TLI (Top Level Hardware Interrupt) This hardware interrupt occurs when a specific edge is detected on the dedicated TLI pin. It will be serviced according to the flowchart in Figure 18 as a trap. Caution: A TRAP instruction must not be used in a TLI service routine. External Interrupts External interrupts allow the processor to exit from HALT low power mode. External interrupt sensitivity is software selectable through the External Interrupt Control register (EICR). External interrupt triggered on edge will be latched and the interrupt request automatically cleared upon entering the interrupt service routine. If several input pins of a group connected to the same interrupt line are selected simultaneously, these will be logically ORed. Peripheral Interrupts Usually the peripheral interrupts cause the MCU to exit from HALT mode except those mentioned in the "Interrupt Mapping" table. A peripheral interrupt occurs when a specific flag is set in the peripheral status registers and if the corresponding enable bit is set in the peripheral control register. The general sequence for clearing an interrupt is based on an access to the status register followed by a read or write to an associated register. Note: The clearing sequence resets the internal latch. A pending interrupt (i.e. waiting for being serviced) will therefore be lost if the clear sequence is executed. ST72F521, ST72521B INTERRUPTS (Cont'd) 7.3 INTERRUPTS AND LOW POWER MODES 7.4 CONCURRENT & NESTED MANAGEMENT All interrupts allow the processor to exit the WAIT low power mode. On the contrary, only external and other specified interrupts allow the processor to exit from the HALT modes (see column "Exit from HALT" in "Interrupt Mapping" table). When several pending interrupts are present while exiting HALT mode, the first one serviced can only be an interrupt with exit from HALT mode capability and it is selected through the same decision process shown in Figure 19. Note: If an interrupt, that is not able to Exit from HALT mode, is pending with the highest priority when exiting HALT mode, this interrupt is serviced after the first one serviced. The following Figure 20 and Figure 21 show two different interrupt management modes. The first is called concurrent mode and does not allow an interrupt to be interrupted, unlike the nested mode in Figure 21. The interrupt hardware priority is given in this order from the lowest to the highest: MAIN, IT4, IT3, IT2, IT1, IT0, TLI. The software priority is given for each interrupt. Warning: A stack overflow may occur without notifying the software of the failure. IT0 TRAP IT3 IT4 IT1 SOFTWARE PRIORITY LEVEL TRAP IT0 IT1 IT1 IT2 IT3 RIM IT4 MAIN MAIN 11 / 10 I1 I0 3 1 1 3 1 1 3 1 1 3 1 1 3 1 1 3 1 1 USED STACK = 10 BYTES HARDWARE PRIORITY IT2 Figure 20. Concurrent Interrupt Management 3/0 10 IT0 TRAP IT3 IT4 IT1 SOFTWARE PRIORITY LEVEL TRAP IT0 IT1 IT1 IT2 IT2 IT3 RIM IT4 MAIN 11 / 10 IT4 MAIN I1 I0 3 1 1 3 1 1 2 0 0 1 0 1 3 1 1 3 1 1 USED STACK = 20 BYTES HARDWARE PRIORITY IT2 Figure 21. Nested Interrupt Management 3/0 10 35/215 ST72F521, ST72521B INTERRUPTS (Cont'd) INTERRUPT SOFTWARE PRIORITY REGISTERS (ISPRX) Read/Write (bit 7:4 of ISPR3 are read only) Reset Value: 1111 1111 (FFh) 7.5 INTERRUPT REGISTER DESCRIPTION CPU CC REGISTER INTERRUPT BITS Read/Write Reset Value: 111x 1010 (xAh) 7 1 7 0 1 I1 H I0 N Z Level Low High I1 1 0 0 1 I0 0 1 0 1 These two bits are set/cleared by hardware when entering in interrupt. The loaded value is given by the corresponding bits in the interrupt software priority registers (ISPRx). They can be also set/cleared by software with the RIM, SIM, HALT, WFI, IRET and PUSH/POP instructions (see "Interrupt Dedicated Instruction Set" table). *Note: TLI, TRAP and RESET events can interrupt a level 3 program. 36/215 ISPR0 I1_3 I0_3 I1_2 I0_2 I1_1 I0_1 I1_0 I0_0 ISPR1 I1_7 I0_7 I1_6 I0_6 I1_5 I0_5 I1_4 I0_4 ISPR2 I1_11 I0_11 I1_10 I0_10 I1_9 I0_9 I1_8 I0_8 C Bit 5, 3 = I1, I0 Software Interrupt Priority These two bits indicate the current interrupt software priority. Interrupt Software Priority Level 0 (main) Level 1 Level 2 Level 3 (= interrupt disable*) 0 ISPR3 1 1 1 1 I1_13 I0_13 I1_12 I0_12 These four registers contain the interrupt software priority of each interrupt vector. - Each interrupt vector (except RESET and TRAP) has corresponding bits in these registers where its own software priority is stored. This correspondance is shown in the following table. Vector address ISPRx bits FFFBh-FFFAh FFF9h-FFF8h ... FFE1h-FFE0h I1_0 and I0_0 bits* I1_1 and I0_1 bits ... I1_13 and I0_13 bits - Each I1_x and I0_x bit value in the ISPRx registers has the same meaning as the I1 and I0 bits in the CC register. - Level 0 can not be written (I1_x=1, I0_x=0). In this case, the previously stored value is kept. (example: previous=CFh, write=64h, result=44h) The TLI, RESET, and TRAP vectors have no software priorities. When one is serviced, the I1 and I0 bits of the CC register are both set. *Note: Bits in the ISPRx registers which correspond to the TLI can be read and written but they are not significant in the interrupt process management. Caution: If the I1_x and I0_x bits are modified while the interrupt x is executed the following behaviour has to be considered: If the interrupt x is still pending (new interrupt or flag not cleared) and the new software priority is higher than the previous one, the interrupt x is re-entered. Otherwise, the software priority stays unchanged up to the next interrupt request (after the IRET of the interrupt x). ST72F521, ST72521B INTERRUPTS (Cont'd) Table 6. Dedicated Interrupt Instruction Set Instruction HALT New Description Function/Example Entering Halt mode I1 H 1 I0 N Z C 0 IRET Interrupt routine return Pop CC, A, X, PC JRM Jump if I1:0=11 (level 3) I1:0=11 ? I1 H I0 N Z C JRNM Jump if I1:0<>11 I1:0<>11 ? POP CC Pop CC from the Stack RIM Enable interrupt (level 0 set) Mem => CC I1 H I0 N Z C Load 10 in I1:0 of CC 1 SIM Disable interrupt (level 3 set) Load 11 in I1:0 of CC 1 1 TRAP Software trap Software NMI 1 1 WFI Wait for interrupt 1 0 0 Note: During the execution of an interrupt routine, the HALT, POPCC, RIM, SIM and WFI instructions change the current software priority up to the next IRET instruction or one of the previously mentioned instructions. 37/215 ST72F521, ST72521B INTERRUPTS (Cont'd) Table 7. Interrupt Mapping N Source Block RESET TRAP Register Label Description Reset Exit from Priority HALT/ Order ACTIVE HALT3) N/A Software interrupt External top level interrupt EICR Address Vector yes FFFEh-FFFFh no FFFCh-FFFDh yes FFFAh-FFFBh yes FFF8h-FFF9h yes FFF6h-FFF7h 0 TLI 1 MCC/RTC 2 ei0 3 ei1 External interrupt port F2..0 4 ei2 External interrupt port B3..0 5 ei3 External interrupt port B7..4 6 CAN CAN peripheral interrupts CANISR yes FFEEh-FFEFh 7 SPI SPI peripheral interrupts SPICSR yes1 FFECh-FFEDh 8 TIMER A TIMER A peripheral interrupts TASR no FFEAh-FFEBh 9 TIMER B TIMER B peripheral interrupts TBSR no FFE8h-FFE9h no FFE6h-FFE7h no FFE4h-FFE5h (see periph) no FFE2h-FFE3h ARTCSR yes2 FFE0h-FFE1h Main clock controller time base interrupt MCCSR External interrupt port A3..0 N/A 10 SCI SCI Peripheral interrupts SCISR 11 AVD Auxiliary Voltage detector interrupt SICSR 12 I2C 13 PWM ART Higher Priority I2C Peripheral interrupts PWM ART interrupt Lower Priority yes FFF4h-FFF5h yes FFF2h-FFF3h yes FFF0h-FFF1h Notes: 1. Exit from HALT possible when SPI is in slave mode. 2. Exit from HALT possible when PWM ART is in external clock mode. 3. In Flash devices only a RESET or MCC/RTC interrupt can be used to wake-up from Active Halt mode. 7.6 EXTERNAL INTERRUPTS 7.6.1 I/O Port Interrupt Sensitivity The external interrupt sensitivity is controlled by the IPA, IPB and ISxx bits of the EICR register (Figure 22). This control allows to have up to 4 fully independent external interrupt source sensitivities. Each external interrupt source can be generated on four (or five) different events on the pin: Falling edge Rising edge Falling and rising edge 38/215 Falling edge and low level Rising edge and high level (only for ei0 and ei2) To guarantee correct functionality, the sensitivity bits in the EICR register can be modified only when the I1 and I0 bits of the CC register are both set to 1 (level 3). This means that interrupts must be disabled before changing sensitivity. The pending interrupts are cleared by writing a different value in the ISx[1:0], IPA or IPB bits of the EICR. ST72F521, ST72521B INTERRUPTS (Cont'd) Figure 22. External Interrupt Control bits PORT A [3:0] INTERRUPTS PAOR.3 PADDR.3 EICR IS20 IS21 SENSITIVITY PA3 CONTROL IPA BIT PORT F [2:0] INTERRUPTS IS21 SENSITIVITY PF2 CONTROL PORT B [3:0] INTERRUPTS PBOR.3 PBDDR.3 IS10 SENSITIVITY IPB BIT PB7 ei1 INTERRUPT SOURCE IS11 CONTROL PBOR.7 PBDDR.7 PF2 PF1 PF0 EICR PB3 PORT B [7:4] INTERRUPTS ei0 INTERRUPT SOURCE EICR IS20 PFOR.2 PFDDR.2 PA3 PA2 PA1 PA0 PB3 PB2 PB1 PB0 ei2 INTERRUPT SOURCE EICR IS10 IS11 SENSITIVITY CONTROL PB7 PB6 PB5 PB4 ei3 INTERRUPT SOURCE 39/215 ST72F521, ST72521B 7.7 EXTERNAL INTERRUPT CONTROL REGISTER (EICR) Read/Write Reset Value: 0000 0000 (00h) - ei0 (port A3..0) External Interrupt Sensitivity 7 IS11 0 IS10 IPB IS21 IS20 IPA TLIS TLIE Bit 7:6 = IS1[1:0] ei2 and ei3 sensitivity The interrupt sensitivity, defined using the IS1[1:0] bits, is applied to the following external interrupts: - ei2 (port B3..0) External Interrupt Sensitivity IS11 IS10 IPB bit =0 IPB bit =1 Rising edge & high level 0 0 Falling edge & low level 0 1 Rising edge only Falling edge only 1 0 Falling edge only Rising edge only 1 1 Rising and falling edge IPA bit =1 Falling edge & low level Rising edge & high level 0 0 0 1 Rising edge only Falling edge only 1 0 Falling edge only Rising edge only 1 1 Rising and falling edge - ei1 (port F2..0) IS21 IS20 External Interrupt Sensitivity 0 0 Falling edge & low level 0 1 Rising edge only 1 0 Falling edge only 1 1 Rising and falling edge External Interrupt Sensitivity 0 0 0 1 Rising edge only 1 0 Falling edge only 1 1 Rising and falling edge Falling edge & low level These 2 bits can be written only when I1 and I0 of the CC register are both set to 1 (level 3). Bit 5 = IPB Interrupt polarity for port B This bit is used to invert the sensitivity of the port B [3:0] external interrupts. It can be set and cleared by software only when I1 and I0 of the CC register are both set to 1 (level 3). 0: No sensitivity inversion 1: Sensitivity inversion Bit 4:3 = IS2[1:0] ei0 and ei1 sensitivity The interrupt sensitivity, defined using the IS2[1:0] bits, is applied to the following external interrupts: 40/215 IPA bit =0 These 2 bits can be written only when I1 and I0 of the CC register are both set to 1 (level 3). - ei3 (port B7..4) IS11 IS10 IS21 IS20 Bit 2 = IPA Interrupt polarity for port A This bit is used to invert the sensitivity of the port A [3:0] external interrupts. It can be set and cleared by software only when I1 and I0 of the CC register are both set to 1 (level 3). 0: No sensitivity inversion 1: Sensitivity inversion Bit 1 = TLIS TLI sensitivity This bit allows to toggle the TLI edge sensitivity. It can be set and cleared by software only when TLIE bit is cleared. 0: Falling edge 1: Rising edge Bit 0 = TLIE TLI enable This bit allows to enable or disable the TLI capability on the dedicated pin. It is set and cleared by software. 0: TLI disabled 1: TLI enabled Note: a parasitic interrupt can be generated when clearing the TLIE bit. ST72F521, ST72521B INTERRUPTS (Cont'd) Table 8. Nested Interrupts Register Map and Reset Values Address (Hex.) Register Label 7 0024h ISPR0 Reset Value I1_3 1 6 5 I0_3 1 I1_2 1 ei1 ISPR1 Reset Value I1_7 1 0026h ISPR2 Reset Value 0027h ISPR3 Reset Value EICR Reset Value I0_2 1 I1_1 1 2 1 MCC CAN I0_7 1 I1_6 1 I1_11 1 I0_11 1 I1_10 1 I0_10 1 1 IS11 0 1 IS10 0 1 IPB 0 1 IS21 0 AVD 0028h 3 ei0 SPI 0025h 4 I0_6 1 SCI 0 TLI I0_1 1 1 1 ei3 ei2 I1_5 I0_5 1 1 TIMER B I1_9 I0_9 1 1 PWMART I1_13 I0_13 1 1 IS20 IPA 0 0 I1_4 I0_4 1 1 TIMER A I1_8 I0_8 1 1 I2C I1_12 I0_12 1 1 TLIS TLIE 0 0 41/215 ST72F521, ST72521B 8 POWER SAVING MODES 8.1 INTRODUCTION 8.2 SLOW MODE To give a large measure of flexibility to the application in terms of power consumption, four main power saving modes are implemented in the ST7 (see Figure 23): SLOW, WAIT (SLOW WAIT), ACTIVE HALT and HALT. After a RESET the normal operating mode is selected by default (RUN mode). This mode drives the device (CPU and embedded peripherals) by means of a master clock which is based on the main oscillator frequency divided or multiplied by 2 (fOSC2). From RUN mode, the different power saving modes may be selected by setting the relevant register bits or by calling the specific ST7 software instruction whose action depends on the oscillator status. This mode has two targets: - To reduce power consumption by decreasing the internal clock in the device, - To adapt the internal clock frequency (fCPU) to the available supply voltage. SLOW mode is controlled by three bits in the MCCSR register: the SMS bit which enables or disables Slow mode and two CPx bits which select the internal slow frequency (fCPU). In this mode, the master clock frequency (fOSC2) can be divided by 2, 4, 8 or 16. The CPU and peripherals are clocked at this lower frequency (fCPU). Note: SLOW-WAIT mode is activated when entering the WAIT mode while the device is already in SLOW mode. Figure 23. Power Saving Mode Transitions Figure 24. SLOW Mode Clock Transitions High fOSC2/2 fOSC2/4 fOSC2 MCCSR SLOW WAIT CP1:0 00 01 SMS SLOW WAIT NEW SLOW FREQUENCY REQUEST ACTIVE HALT HALT Low POWER CONSUMPTION 42/215 fOSC2 fCPU RUN NORMAL RUN MODE REQUEST ST72F521, ST72521B POWER SAVING MODES (Cont'd) 8.3 WAIT MODE WAIT mode places the MCU in a low power consumption mode by stopping the CPU. This power saving mode is selected by calling the `WFI' instruction. All peripherals remain active. During WAIT mode, the I[1:0] bits of the CC register are forced to `10', to enable all interrupts. All other registers and memory remain unchanged. The MCU remains in WAIT mode until an interrupt or RESET occurs, whereupon the Program Counter branches to the starting address of the interrupt or Reset service routine. The MCU will remain in WAIT mode until a Reset or an Interrupt occurs, causing it to wake up. Refer to Figure 25. Figure 25. WAIT Mode Flow-chart WFI INSTRUCTION OSCILLATOR PERIPHERALS CPU I[1:0] BITS ON ON OFF 10 N RESET Y N INTERRUPT Y OSCILLATOR PERIPHERALS CPU I[1:0] BITS ON OFF ON 10 256 OR 4096 CPU CLOCK CYCLE DELAY OSCILLATOR ON PERIPHERALS ON CPU ON I[1:0] BITS XX 1) FETCH RESET VECTOR OR SERVICE INTERRUPT Note: 1. Before servicing an interrupt, the CC register is pushed on the stack. The I[1:0] bits of the CC register are set to the current software priority level of the interrupt routine and recovered when the CC register is popped. 43/215 ST72F521, ST72521B POWER SAVING MODES (Cont'd) 8.4 ACTIVE-HALT AND HALT MODES ACTIVE-HALT and HALT modes are the two lowest power consumption modes of the MCU. They are both entered by executing the `HALT' instruction. The decision to enter either in ACTIVE-HALT or HALT mode is given by the MCC/RTC interrupt enable flag (OIE bit in MCCSR register). MCCSR OIE bit Figure 26. ACTIVE-HALT Timing Overview RUN ACTIVE 256 OR 4096 CPU HALT CYCLE DELAY 1) Power Saving Mode entered when HALT instruction is executed 0 HALT mode 1 ACTIVE-HALT mode 8.4.1 ACTIVE-HALT MODE ACTIVE-HALT mode is the lowest power consumption mode of the MCU with a real time clock available. It is entered by executing the `HALT' instruction when the OIE bit of the Main Clock Controller Status register (MCCSR) is set (see section 10.2 on page 58 for more details on the MCCSR register). The MCU can exit ACTIVE-HALT mode on reception of an MCC/RTC interrupt or a RESET. In ROM devices, external interrupts can be used to wakeup the MCU. When exiting ACTIVE-HALT mode by means of an interrupt, no 256 or 4096 CPU cycle delay occurs. The CPU resumes operation by servicing the interrupt or by fetching the reset vector which woke it up (see Figure 27). When entering ACTIVE-HALT mode, the I[1:0] bits in the CC register are forced to `10b' to enable interrupts. Therefore, if an interrupt is pending, the MCU wakes up immediately. In ACTIVE-HALT mode, only the main oscillator and its associated counter (MCC/RTC) are running to keep a wake-up time base. All other peripherals are not clocked except those which get their clock supply from another clock generator (such as external or auxiliary oscillator). The safeguard against staying locked in ACTIVEHALT mode is provided by the oscillator interrupt. Note: As soon as the interrupt capability of one of the oscillators is selected (MCCSR.OIE bit set), entering ACTIVE-HALT mode while the Watchdog is active does not generate a RESET. This means that the device cannot spend more than a defined delay in this power saving mode. CAUTION: When exiting ACTIVE-HALT mode following an MCC/RTC interrupt, OIE bit of MCCSR register must not be cleared before tDELAY after the interrupt occurs (tDELAY = 256 or 4096 tCPU de- 44/215 lay depending on option byte). Otherwise, the ST7 enters HALT mode for the remaining tDELAY period. HALT INSTRUCTION [MCCSR.OIE=1] RESET OR INTERRUPT RUN FETCH VECTOR Figure 27. ACTIVE-HALT Mode Flow-chart HALT INSTRUCTION (MCCSR.OIE=1) OSCILLATOR PERIPHERALS 2) CPU I[1:0] BITS N N INTERRUPT 4) Y ON OFF OFF 10 RESET Y OSCILLATOR PERIPHERALS CPU I[1:0] BITS ON OFF ON XX 3) 256 OR 4096 CPU CLOCK CYCLE DELAY OSCILLATOR PERIPHERALS CPU I[1:0] BITS ON ON ON XX 3) FETCH RESET VECTOR OR SERVICE INTERRUPT Notes: 1. This delay occurs only if the MCU exits ACTIVEHALT mode by means of a RESET. 2. Peripheral clocked with an external clock source can still be active. 3. Before servicing an interrupt, the CC register is pushed on the stack. The I[1:0] bits of the CC register are set to the current software priority level of the interrupt routine and restored when the CC register is popped. 4. In flash devices only the MCC/RTC interrupt can exit the MCU from ACTIVE-HALT mode. ST72F521, ST72521B POWER SAVING MODES (Cont'd) 8.4.2 HALT MODE The HALT mode is the lowest power consumption mode of the MCU. It is entered by executing the `HALT' instruction when the OIE bit of the Main Clock Controller Status register (MCCSR) is cleared (see section 10.2 on page 58 for more details on the MCCSR register). The MCU can exit HALT mode on reception of either a specific interrupt (see Table 7, "Interrupt Mapping," on page 38) or a RESET. When exiting HALT mode by means of a RESET or an interrupt, the oscillator is immediately turned on and the 256 or 4096 CPU cycle delay is used to stabilize the oscillator. After the start up delay, the CPU resumes operation by servicing the interrupt or by fetching the reset vector which woke it up (see Figure 29). When entering HALT mode, the I[1:0] bits in the CC register are forced to `10b'to enable interrupts. Therefore, if an interrupt is pending, the MCU wakes up immediately. In HALT mode, the main oscillator is turned off causing all internal processing to be stopped, including the operation of the on-chip peripherals. All peripherals are not clocked except the ones which get their clock supply from another clock generator (such as an external or auxiliary oscillator). The compatibility of Watchdog operation with HALT mode is configured by the "WDGHALT" option bit of the option byte. The HALT instruction when executed while the Watchdog system is enabled, can generate a Watchdog RESET (see section 14.1 on page 201 for more details). Figure 29. HALT Mode Flow-chart HALT INSTRUCTION (MCCSR.OIE=0) ENABLE WDGHALT 1) WATCHDOG 0 DISABLE 1 WATCHDOG RESET OSCILLATOR OFF PERIPHERALS 2) OFF CPU OFF I[1:0] BITS 10 N RESET N Y INTERRUPT 3) Y OSCILLATOR ON PERIPHERALS OFF CPU ON I[1:0] BITS XX 4) 256 OR 4096 CPU CLOCK CYCLE DELAY OSCILLATOR ON PERIPHERALS ON CPU ON I[1:0] BITS XX 4) Figure 28. HALT Timing Overview RUN HALT HALT INSTRUCTION [MCCSR.OIE=0] 256 OR 4096 CPU CYCLE DELAY FETCH RESET VECTOR OR SERVICE INTERRUPT RUN RESET OR INTERRUPT FETCH VECTOR Notes: 1. WDGHALT is an option bit. See option byte section for more details. 2. Peripheral clocked with an external clock source can still be active. 3. Only some specific interrupts can exit the MCU from HALT mode (such as external interrupt). Refer to Table 7, "Interrupt Mapping," on page 38 for more details. 4. Before servicing an interrupt, the CC register is pushed on the stack. The I[1:0] bits of the CC register are set to the current software priority level of the interrupt routine and recovered when the CC register is popped. 45/215 ST72F521, ST72521B POWER SAVING MODES (Cont'd) 8.4.2.1 Halt Mode Recommendations - Make sure that an external event is available to wake up the microcontroller from Halt mode. - When using an external interrupt to wake up the microcontroller, reinitialize the corresponding I/O as "Input Pull-up with Interrupt" before executing the HALT instruction. The main reason for this is that the I/O may be wrongly configured due to external interference or by an unforeseen logical condition. - For the same reason, reinitialize the level sensitiveness of each external interrupt as a precautionary measure. - The opcode for the HALT instruction is 0x8E. To avoid an unexpected HALT instruction due to a program counter failure, it is advised to clear all occurrences of the data value 0x8E from memo- 46/215 ry. For example, avoid defining a constant in ROM with the value 0x8E. - As the HALT instruction clears the interrupt mask in the CC register to allow interrupts, the user may choose to clear all pending interrupt bits before executing the HALT instruction. This avoids entering other peripheral interrupt routines after executing the external interrupt routine corresponding to the wake-up event (reset or external interrupt). Related Documentation AN 980: ST7 Keypad Decoding Techniques, Implementing Wake-Up on Keystroke AN1014: How to Minimize the ST7 Power Consumption AN1605: Using an active RC to wakeup the ST7LITE0 from power saving mode ST72F521, ST72521B 9 I/O PORTS 9.1 INTRODUCTION The I/O ports offer different functional modes: - transfer of data through digital inputs and outputs and for specific pins: - external interrupt generation - alternate signal input/output for the on-chip peripherals. An I/O port contains up to 8 pins. Each pin can be programmed independently as digital input (with or without interrupt generation) or digital output. 9.2 FUNCTIONAL DESCRIPTION Each port has 2 main registers: - Data Register (DR) - Data Direction Register (DDR) and one optional register: - Option Register (OR) Each I/O pin may be programmed using the corresponding register bits in the DDR and OR registers: bit X corresponding to pin X of the port. The same correspondence is used for the DR register. The following description takes into account the OR register, (for specific ports which do not provide this register refer to the I/O Port Implementation section). The generic I/O block diagram is shown in Figure 30 9.2.1 Input Modes The input configuration is selected by clearing the corresponding DDR register bit. In this case, reading the DR register returns the digital value applied to the external I/O pin. Different input modes can be selected by software through the OR register. Notes: 1. Writing the DR register modifies the latch value but does not affect the pin status. 2. When switching from input to output mode, the DR register has to be written first to drive the correct level on the pin as soon as the port is configured as an output. 3. Do not use read/modify/write instructions (BSET or BRES) to modify the DR register External interrupt function When an I/O is configured as Input with Interrupt, an event on this I/O can generate an external interrupt request to the CPU. Each pin can independently generate an interrupt request. The interrupt sensitivity is independently programmable using the sensitivity bits in the EICR register. Each external interrupt vector is linked to a dedicated group of I/O port pins (see pinout description and interrupt section). If several input pins are selected simultaneously as interrupt sources, these are first detected according to the sensitivity bits in the EICR register and then logically ORed. The external interrupts are hardware interrupts, which means that the request latch (not accessible directly by the application) is automatically cleared when the corresponding interrupt vector is fetched. To clear an unwanted pending interrupt by software, the sensitivity bits in the EICR register must be modified. 9.2.2 Output Modes The output configuration is selected by setting the corresponding DDR register bit. In this case, writing the DR register applies this digital value to the I/O pin through the latch. Then reading the DR register returns the previously stored value. Two different output modes can be selected by software through the OR register: Output push-pull and open-drain. DR register value and output pin status: DR 0 1 Push-pull VSS VDD Open-drain Vss Floating 9.2.3 Alternate Functions When an on-chip peripheral is configured to use a pin, the alternate function is automatically selected. This alternate function takes priority over the standard I/O programming. When the signal is coming from an on-chip peripheral, the I/O pin is automatically configured in output mode (push-pull or open drain according to the peripheral). When the signal is going to an on-chip peripheral, the I/O pin must be configured in input mode. In this case, the pin state is also digitally readable by addressing the DR register. Note: Input pull-up configuration can cause unexpected value at the input of the alternate peripheral input. When an on-chip peripheral use a pin as input and output, this pin has to be configured in input floating mode. 47/215 ST72F521, ST72521B I/O PORTS (Cont'd) Figure 30. I/O Port General Block Diagram ALTERNATE OUTPUT REGISTER ACCESS 1 P-BUFFER (see table below) VDD 0 ALTERNATE ENABLE PULL-UP (see table below) DR VDD DDR PULL-UP CONDITION DATA BUS OR PAD If implemented OR SEL N-BUFFER DIODES (see table below) DDR SEL DR SEL ANALOG INPUT CMOS SCHMITT TRIGGER 1 0 ALTERNATE INPUT EXTERNAL INTERRUPT SOURCE (eix) Table 9. I/O Port Mode Options Configuration Mode Input Output Floating with/without Interrupt Pull-up with/without Interrupt Push-pull Open Drain (logic level) True Open Drain Legend: NI - not implemented Off - implemented not activated On - implemented and activated 48/215 Pull-Up P-Buffer Off On Off Off NI On Off NI Diodes to VDD On to VSS On NI (see note) Note: The diode to VDD is not implemented in the true open drain pads. A local protection between the pad and VSS is implemented to protect the device against positive stress. ST72F521, ST72521B I/O PORTS (Cont'd) Table 10. I/O Port Configurations Hardware Configuration NOT IMPLEMENTED IN TRUE OPEN DRAIN I/O PORTS DR REGISTER ACCESS VDD RPU PULL-UP CONDITION DR REGISTER PAD W DATA BUS INPUT 1) R ALTERNATE INPUT EXTERNAL INTERRUPT SOURCE (eix) INTERRUPT CONDITION PUSH-PULL OUTPUT 2) OPEN-DRAIN OUTPUT 2) ANALOG INPUT NOT IMPLEMENTED IN TRUE OPEN DRAIN I/O PORTS DR REGISTER ACCESS VDD RPU DR REGISTER PAD ALTERNATE ENABLE NOT IMPLEMENTED IN TRUE OPEN DRAIN I/O PORTS R/W DATA BUS ALTERNATE OUTPUT DR REGISTER ACCESS VDD RPU PAD DR REGISTER ALTERNATE ENABLE R/W DATA BUS ALTERNATE OUTPUT Notes: 1. When the I/O port is in input configuration and the associated alternate function is enabled as an output, reading the DR register will read the alternate function output status. 2. When the I/O port is in output configuration and the associated alternate function is enabled as an input, the alternate function reads the pin status given by the DR register content. 49/215 ST72F521, ST72521B I/O PORTS (Cont'd) CAUTION: The alternate function must not be activated as long as the pin is configured as input with interrupt, in order to avoid generating spurious interrupts. Analog alternate function When the pin is used as an ADC input, the I/O must be configured as floating input. The analog multiplexer (controlled by the ADC registers) switches the analog voltage present on the selected pin to the common analog rail which is connected to the ADC input. It is recommended not to change the voltage level or loading on any port pin while conversion is in progress. Furthermore it is recommended not to have clocking pins located close to a selected analog pin. WARNING: The analog input voltage level must be within the limits stated in the absolute maximum ratings. Figure 31. Interrupt I/O Port State Transitions 01 00 10 11 INPUT floating/pull-up interrupt INPUT floating (reset state) OUTPUT open-drain OUTPUT push-pull XX = DDR, OR 9.4 LOW POWER MODES Mode WAIT HALT Description No effect on I/O ports. External interrupts cause the device to exit from WAIT mode. No effect on I/O ports. External interrupts cause the device to exit from HALT mode. 9.5 INTERRUPTS 9.3 I/O PORT IMPLEMENTATION The hardware implementation on each I/O port depends on the settings in the DDR and OR registers and specific feature of the I/O port such as ADC Input or true open drain. Switching these I/O ports from one state to another should be done in a sequence that prevents unwanted side effects. Recommended safe transitions are illustrated in Figure 31 Other transitions are potentially risky and should be avoided, since they are likely to present unwanted side-effects such as spurious interrupt generation. 50/215 The external interrupt event generates an interrupt if the corresponding configuration is selected with DDR and OR registers and the interrupt mask in the CC register is not active (RIM instruction). Interrupt Event External interrupt on selected external event Enable Event Control Flag Bit - DDRx ORx Exit from Wait Exit from Halt Yes Yes ST72F521, ST72521B I/O PORTS (Cont'd) 9.5.1 I/O Port Implementation The I/O port register configurations are summarised as follows. PA3, PB7, PB3, PF2 (without pull-up) MODE floating input floating interrupt input open drain output push-pull output Standard Ports PA5:4, PC7:0, PD7:0, PE7:34, PE1:0, PF7:3, PG7:0, PH7:0 MODE floating input pull-up input open drain output push-pull output DDR 0 0 1 1 OR 0 1 0 1 DDR 0 0 1 1 OR 0 1 0 1 True Open Drain Ports PA7:6 MODE floating input open drain (high sink ports) Interrupt Ports PA2:0, PB6:5, PB4, PB2:0, PF1:0 (with pull-up) MODE floating input pull-up interrupt input open drain output push-pull output DDR 0 0 1 1 OR 0 1 0 1 DDR 0 1 Pull-up Input Port (CANTX requirement) PE2 MODE pull-up input Table 11. Port Configuration Port Port A Port B Port C Port D Port E Port F Port G Port H Pin name PA7:6 PA5:4 PA3 PA2:0 PB7, PB3 PB6:5, PB4, PB2:0 PC7:0 PD7:0 PE7:3, PE1:0 PE2 PF7:3 PF2 PF1:0 PG7:0 PH7:0 Input Output OR = 0 OR = 1 floating OR = 0 OR = 1 floating floating floating floating pull-up floating interrupt pull-up interrupt floating interrupt true open-drain open drain push-pull open drain push-pull open drain push-pull open drain push-pull floating pull-up interrupt open drain push-pull floating floating floating pull-up open drain pull-up open drain pull-up open drain pull-up input only * pull-up open drain floating interrupt open drain pull-up interrupt open drain pull-up open drain pull-up open drain push-pull push-pull push-pull floating floating floating floating floating push-pull push-pull push-pull push-pull push-pull * Note: when the CANTX alternate function is selected the I/O port operates in output push-pull mode. 51/215 ST72F521, ST72521B I/O PORTS (Cont'd) Table 12. I/O Port Register Map and Reset Values Address (Hex.) Register Label Reset Value of all I/O port registers 0000h PADR 0001h PADDR 0002h PAOR 0003h PBDR 0004h PBDDR 0005h PBOR 0006h PCDR 0007h PCDDR 0008h PCOR 0009h PDDR 000Ah PDDDR 000Bh PDOR 000Ch PEDR 000Dh PEDDR 000Eh PEOR 000Fh PFDR 0010h PFDDR 0011h PFOR 0012h PGDR 0013h PGDDR 0014h PGOR 0015h PHDR 0016h PHDDR 0017h PHOR 7 6 5 4 3 2 1 0 0 0 0 0 0 0 0 0 MSB LSB MSB LSB MSB LSB MSB LSB MSB LSB MSB LSB MSB LSB MSB LSB Related Documentation AN 970: SPI Communication between ST7 and EEPROM 52/215 AN1045: S/W implementation of I2C bus master AN1048: Software LCD driver ST72F521, ST72521B 10 ON-CHIP PERIPHERALS 10.1 WATCHDOG TIMER (WDG) 10.1.1 Introduction The Watchdog timer is used to detect the occurrence of a software fault, usually generated by external interference or by unforeseen logical conditions, which causes the application program to abandon its normal sequence. The Watchdog circuit generates an MCU reset on expiry of a programmed time period, unless the program refreshes the counter's contents before the T6 bit becomes cleared. 10.1.2 Main Features Programmable free-running downcounter Programmable reset Reset (if watchdog activated) when the T6 bit reaches zero Optional reset on HALT instruction (configurable by option byte) Hardware Watchdog selectable by option byte 10.1.3 Functional Description The counter value stored in the Watchdog Control register (WDGCR bits T[6:0]), is decremented every 16384 fOSC2 cycles (approx.), and the length of the timeout period can be programmed by the user in 64 increments. If the watchdog is activated (the WDGA bit is set) and when the 7-bit timer (bits T[6:0]) rolls over from 40h to 3Fh (T6 becomes cleared), it initiates a reset cycle pulling low the reset pin for typically 500ns. The application program must write in the WDGCR register at regular intervals during normal operation to prevent an MCU reset. This downcounter is free-running: it counts down even if the watchdog is disabled. The value to be stored in the WDGCR register must be between FFh and C0h: - The WDGA bit is set (watchdog enabled) - The T6 bit is set to prevent generating an immediate reset - The T[5:0] bits contain the number of increments which represents the time delay before the watchdog produces a reset (see Figure 33. Approximate Timeout Duration). The timing varies between a minimum and a maximum value due to the unknown status of the prescaler when writing to the WDGCR register (see Figure 34). Following a reset, the watchdog is disabled. Once activated it cannot be disabled, except by a reset. The T6 bit can be used to generate a software reset (the WDGA bit is set and the T6 bit is cleared). If the watchdog is activated, the HALT instruction will generate a Reset. Figure 32. Watchdog Block Diagram RESET fOSC2 MCC/RTC WATCHDOG CONTROL REGISTER (WDGCR) DIV 64 WDGA T6 T5 T4 T3 T2 T1 T0 6-BIT DOWNCOUNTER (CNT) 12-BIT MCC RTC COUNTER MSB 11 LSB 6 5 0 TB[1:0] bits (MCCSR Register) WDG PRESCALER DIV 4 53/215 ST72F521, ST72521B WATCHDOG TIMER (Cont'd) 10.1.4 How to Program the Watchdog Timeout Figure 33 shows the linear relationship between the 6-bit value to be loaded in the Watchdog Counter (CNT) and the resulting timeout duration in milliseconds. This can be used for a quick calculation without taking the timing variations into account. If more precision is needed, use the formulae in Figure 34. Caution: When writing to the WDGCR register, always write 1 in the T6 bit to avoid generating an immediate reset. Figure 33. Approximate Timeout Duration 3F 38 CNT Value (hex.) 30 28 20 18 10 08 00 1.5 18 34 50 65 82 Watchdog timeout (ms) @ 8 MHz. fOSC2 54/215 98 114 128 ST72F521, ST72521B WATCHDOG TIMER (Cont'd) Figure 34. Exact Timeout Duration (tmin and tmax) WHERE: tmin0 = (LSB + 128) x 64 x tOSC2 tmax0 = 16384 x tOSC2 tOSC2 = 125ns if fOSC2=8 MHz CNT = Value of T[5:0] bits in the WDGCR register (6 bits) MSB and LSB are values from the table below depending on the timebase selected by the TB[1:0] bits in the MCCSR register TB1 Bit TB0 Bit (MCCSR Reg.) (MCCSR Reg.) 0 0 0 1 1 0 1 1 Selected MCCSR Timebase MSB LSB 2ms 4ms 10ms 25ms 4 8 20 49 59 53 35 54 To calculate the minimum Watchdog Timeout (tmin): IF CNT < MSB ------------4 THEN t min = t min0 + 16384 x CNT x tosc2 4CNT ELSE t min = t min0 + 16384 x CNT - 4CNT ----------------- + ( 192 + LSB ) x 64 x ----------------MSB MSB x t osc2 To calculate the maximum Watchdog Timeout (tmax): IF CNT MSB ------------4 THEN t max = t max0 + 16384 x CNT x t osc2 4CNT ELSE t max = t max0 + 16384 x CNT - 4CNT ----------------- + ( 192 + LSB ) x 64 x ----------------MSB MSB x t osc2 Note: In the above formulae, division results must be rounded down to the next integer value. Example: With 2ms timeout selected in MCCSR register Value of T[5:0] Bits in WDGCR Register (Hex.) 00 3F Min. Watchdog Timeout (ms) tmin 1.496 128 Max. Watchdog Timeout (ms) tmax 2.048 128.552 55/215 ST72F521, ST72521B WATCHDOG TIMER (Cont'd) 10.1.5 Low Power Modes Mode SLOW WAIT Description No effect on Watchdog. No effect on Watchdog. OIE bit in MCCSR register WDGHALT bit in Option Byte 0 0 0 1 1 x HALT No Watchdog reset is generated. The MCU enters Halt mode. The Watchdog counter is decremented once and then stops counting and is no longer able to generate a watchdog reset until the MCU receives an external interrupt or a reset. If an external interrupt is received, the Watchdog restarts counting after 256 or 4096 CPU clocks. If a reset is generated, the Watchdog is disabled (reset state) unless Hardware Watchdog is selected by option byte. For application recommendations see Section 10.1.7 below. A reset is generated. No reset is generated. The MCU enters Active Halt mode. The Watchdog counter is not decremented. It stop counting. When the MCU receives an oscillator interrupt or external interrupt, the Watchdog restarts counting immediately. When the MCU receives a reset the Watchdog restarts counting after 256 or 4096 CPU clocks. 10.1.6 Hardware Watchdog Option If Hardware Watchdog is selected by option byte, the watchdog is always active and the WDGA bit in the WDGCR is not used. Refer to the Option Byte description. 10.1.7 Using Halt Mode with the WDG (WDGHALT option) The following recommendation applies if Halt mode is used when the watchdog is enabled. - Before executing the HALT instruction, refresh the WDG counter, to avoid an unexpected WDG reset immediately after waking up the microcontroller. 10.1.8 Interrupts None. 56/215 10.1.9 Register Description CONTROL REGISTER (WDGCR) Read/Write Reset Value: 0111 1111 (7Fh) 7 WDGA 0 T6 T5 T4 T3 T2 T1 T0 Bit 7 = WDGA Activation bit. This bit is set by software and only cleared by hardware after a reset. When WDGA = 1, the watchdog can generate a reset. 0: Watchdog disabled 1: Watchdog enabled Note: This bit is not used if the hardware watchdog option is enabled by option byte. Bit 6:0 = T[6:0] 7-bit counter (MSB to LSB). These bits contain the value of the watchdog counter. It is decremented every 16384 fOSC2 cycles (approx.). A reset is produced when it rolls over from 40h to 3Fh (T6 becomes cleared). ST72F521, ST72521B Table 13. Watchdog Timer Register Map and Reset Values Address (Hex.) Register Label 7 6 5 4 3 2 1 0 002Ah WDGCR Reset Value WDGA 0 T6 1 T5 1 T4 1 T3 1 T2 1 T1 1 T0 1 57/215 ST72F521, ST72521B 10.2 MAIN CLOCK CONTROLLER WITH REAL TIME CLOCK AND BEEPER (MCC/RTC) The Main Clock Controller consists of three different functions: a programmable CPU clock prescaler a clock-out signal to supply external devices a real time clock timer with interrupt capability Each function can be used independently and simultaneously. 10.2.1 Programmable CPU Clock Prescaler The programmable CPU clock prescaler supplies the clock for the ST7 CPU and its internal peripherals. It manages SLOW power saving mode (See Section 8.2 SLOW MODE for more details). The prescaler selects the fCPU main clock frequency and is controlled by three bits in the MCCSR register: CP[1:0] and SMS. 10.2.2 Clock-out Capability The clock-out capability is an alternate function of an I/O port pin that outputs a fCPU clock to drive external devices. It is controlled by the MCO bit in the MCCSR register. CAUTION: When selected, the clock out pin suspends the clock during ACTIVE-HALT mode. 10.2.3 Real Time Clock Timer (RTC) The counter of the real time clock timer allows an interrupt to be generated based on an accurate real time clock. Four different time bases depending directly on fOSC2 are available. The whole functionality is controlled by four bits of the MCCSR register: TB[1:0], OIE and OIF. When the RTC interrupt is enabled (OIE bit set), the ST7 enters ACTIVE-HALT mode when the HALT instruction is executed. See Section 8.4 ACTIVE-HALT AND HALT MODES for more details. 10.2.4 Beeper The beep function is controlled by the MCCBCR register. It can output three selectable frequencies on the BEEP pin (I/O port alternate function). Figure 35. Main Clock Controller (MCC/RTC) Block Diagram BC1 BC0 MCCBCR BEEP BEEP SIGNAL SELECTION MCO 12-BIT MCC RTC COUNTER DIV 64 MCO CP1 CP0 SMS TB1 TB0 OIE MCCSR fOSC2 DIV 2, 4, 8, 16 OIF MCC/RTC INTERRUPT 1 0 58/215 TO WATCHDOG TIMER fCPU CPU CLOCK TO CPU AND PERIPHERALS ST72F521, ST72521B MAIN CLOCK CONTROLLER WITH REAL TIME CLOCK (Cont'd) 10.2.5 Low Power Modes Bit 6:5 = CP[1:0] CPU clock prescaler Mode Description These bits select the CPU clock prescaler which is No effect on MCC/RTC peripheral. applied in the different slow modes. Their action is WAIT MCC/RTC interrupt cause the device to exit conditioned by the setting of the SMS bit. These from WAIT mode. two bits are set and cleared by software ACTIVEHALT HALT No effect on MCC/RTC counter (OIE bit is set), the registers are frozen. MCC/RTC interrupt cause the device to exit from ACTIVE-HALT mode. MCC/RTC counter and registers are frozen. MCC/RTC operation resumes when the MCU is woken up by an interrupt with "exit from HALT" capability. 10.2.6 Interrupts The MCC/RTC interrupt event generates an interrupt if the OIE bit of the MCCSR register is set and the interrupt mask in the CC register is not active (RIM instruction). Interrupt Event Time base overflow event Enable Event Control Flag Bit OIF OIE Exit from Wait Exit from Halt Yes No 1) Note: The MCC/RTC interrupt wakes up the MCU from ACTIVE-HALT mode, not from HALT mode. 10.2.7 Register Description MCC CONTROL/STATUS REGISTER (MCCSR) Read/Write Reset Value: 0000 0000 (00h) 7 MCO 0 CP1 CP0 SMS TB1 TB0 OIE fCPU in SLOW mode CP1 CP0 fOSC2 / 2 0 0 fOSC2 / 4 0 1 fOSC2 / 8 1 0 fOSC2 / 16 1 1 Bit 4 = SMS Slow mode select This bit is set and cleared by software. 0: Normal mode. fCPU = fOSC2 1: Slow mode. fCPU is given by CP1, CP0 See Section 8.2 SLOW MODE and Section 10.2 MAIN CLOCK CONTROLLER WITH REAL TIME CLOCK AND BEEPER (MCC/RTC) for more details. Bit 3:2 = TB[1:0] Time base control These bits select the programmable divider time base. They are set and cleared by software. Time Base Counter Prescaler f OSC2 =4MHz fOSC2=8MHz TB1 TB0 16000 4ms 2ms 0 0 32000 8ms 4ms 0 1 80000 20ms 10ms 1 0 200000 50ms 25ms 1 1 A modification of the time base is taken into account at the end of the current period (previously set) to avoid an unwanted time shift. This allows to use this time base as a real time clock. OIF Bit 7 = MCO Main clock out selection This bit enables the MCO alternate function on the PF0 I/O port. It is set and cleared by software. 0: MCO alternate function disabled (I/O pin free for general-purpose I/O) 1: MCO alternate function enabled (fCPU on I/O port) Note: To reduce power consumption, the MCO function is not active in ACTIVE-HALT mode. Bit 1 = OIE Oscillator interrupt enable This bit set and cleared by software. 0: Oscillator interrupt disabled 1: Oscillator interrupt enabled This interrupt can be used to exit from ACTIVEHALT mode. When this bit is set, calling the ST7 software HALT instruction enters the ACTIVE-HALT power saving mode. 59/215 ST72F521, ST72521B MAIN CLOCK CONTROLLER WITH REAL TIME CLOCK (Cont'd) MCC BEEP CONTROL REGISTER (MCCBCR) Bit 0 = OIF Oscillator interrupt flag This bit is set by hardware and cleared by software Read/Write reading the MCCSR register. It indicates when set Reset Value: 0000 0000 (00h) that the main oscillator has reached the selected elapsed time (TB1:0). 7 0 0: Timeout not reached 1: Timeout reached 0 0 0 0 0 0 BC1 BC0 CAUTION: The BRES and BSET instructions must not be used on the MCCSR register to avoid Bit 7:2 = Reserved, must be kept cleared. unintentionally clearing the OIF bit. Bit 1:0 = BC[1:0] Beep control These 2 bits select the PF1 pin beep capability. BC1 BC0 Beep mode with fOSC2=8MHz 0 0 Off 0 1 ~2-KHz 1 0 ~1-KHz 1 1 ~500-Hz Output Beep signal ~50% duty cycle The beep output signal is available in ACTIVEHALT mode but has to be disabled to reduce the consumption. Table 14. Main Clock Controller Register Map and Reset Values Address (Hex.) 002Bh 002Ch 002Dh 60/215 Register Label SICSR Reset Value MCCSR Reset Value MCCBCR Reset Value 7 6 5 4 3 2 1 0 AVDS 0 MCO 0 AVDIE 0 CP1 0 AVDF 0 CP0 0 LVDRF x SMS 0 0 TB1 0 0 TB0 0 0 0 0 0 0 0 0 OIE 0 BC1 0 WDGRF x OIF 0 BC0 0 ST72F521, ST72521B 10.3 PWM AUTO-RELOAD TIMER (ART) 10.3.1 Introduction The Pulse Width Modulated Auto-Reload Timer on-chip peripheral consists of an 8-bit auto reload counter with compare/capture capabilities and of a 7-bit prescaler clock source. These resources allow five possible operating modes: - Generation of up to 4 independent PWM signals - Output compare and Time base interrupt - Up to two input capture functions - External event detector - Up to two external interrupt sources The three first modes can be used together with a single counter frequency. The timer can be used to wake up the MCU from WAIT and HALT modes. Figure 36. PWM Auto-Reload Timer Block Diagram OEx PWMCR OCRx REGISTER OPx DCRx REGISTER LOAD PWMx PORT ALTERNATE FUNCTION POLARITY CONTROL COMPARE 8-BIT COUNTER ARR REGISTER INPUT CAPTURE CONTROL ARTICx ICSx ARTCLK ICIEx LOAD (CAR REGISTER) LOAD ICFx ICRx REGISTER ICCSR ICx INTERRUPT fEXT fCOUNTER fCPU MUX fINPUT EXCL PROGRAMMABLE PRESCALER CC2 CC1 CC0 TCE FCRL OIE OVF ARTCSR OVF INTERRUPT 61/215 ST72F521, ST72521B PWM AUTO-RELOAD TIMER (Cont'd) 10.3.2 Functional Description Counter The free running 8-bit counter is fed by the output of the prescaler, and is incremented on every rising edge of the clock signal. It is possible to read or write the contents of the counter on the fly by reading or writing the Counter Access register (ARTCAR). When a counter overflow occurs, the counter is automatically reloaded with the contents of the ARTARR register (the prescaler is not affected). Counter clock and prescaler The counter clock frequency is given by: fCOUNTER = fINPUT / 2CC[2:0] The timer counter's input clock (fINPUT) feeds the 7-bit programmable prescaler, which selects one of the 8 available taps of the prescaler, as defined by CC[2:0] bits in the Control/Status Register (ARTCSR). Thus the division factor of the prescaler can be set to 2n (where n = 0, 1,..7). This fINPUT frequency source is selected through the EXCL bit of the ARTCSR register and can be either the fCPU or an external input frequency fEXT. The clock input to the counter is enabled by the TCE (Timer Counter Enable) bit in the ARTCSR register. When TCE is reset, the counter is stopped and the prescaler and counter contents are frozen. When TCE is set, the counter runs at the rate of the selected clock source. Counter and Prescaler Initialization After RESET, the counter and the prescaler are cleared and fINPUT = fCPU. The counter can be initialized by: - Writing to the ARTARR register and then setting the FCRL (Force Counter Re-Load) and the TCE (Timer Counter Enable) bits in the ARTCSR register. - Writing to the ARTCAR counter access register, In both cases the 7-bit prescaler is also cleared, whereupon counting will start from a known value. Direct access to the prescaler is not possible. Output compare control The timer compare function is based on four different comparisons with the counter (one for each PWMx output). Each comparison is made between the counter value and an output compare register (OCRx) value. This OCRx register can not be accessed directly, it is loaded from the duty cycle register (PWMDCRx) at each overflow of the counter. This double buffering method avoids glitch generation when changing the duty cycle on the fly. Figure 37. Output compare control fCOUNTER ARTARR=FDh COUNTER FDh FEh FFh OCRx PWMDCRx PWMx 62/215 FDh FEh FFh FDh FEh FDh FDh FEh FEh FFh ST72F521, ST72521B PWM AUTO-RELOAD TIMER (Cont'd) Independent PWM signal generation This mode allows up to four Pulse Width Modulated signals to be generated on the PWMx output pins with minimum core processing overhead. This function is stopped during HALT mode. Each PWMx output signal can be selected independently using the corresponding OEx bit in the PWM Control register (PWMCR). When this bit is set, the corresponding I/O pin is configured as output push-pull alternate function. The PWM signals all have the same frequency which is controlled by the counter period and the ARTARR register value. fPWM = fCOUNTER / (256 - ARTARR) When a counter overflow occurs, the PWMx pin level is changed depending on the corresponding OPx (output polarity) bit in the PWMCR register. When the counter reaches the value contained in one of the output compare register (OCRx) the corresponding PWMx pin level is restored. It should be noted that the reload values will also affect the value and the resolution of the duty cycle of the PWM output signal. To obtain a signal on a PWMx pin, the contents of the OCRx register must be greater than the contents of the ARTARR register. The maximum available resolution for the PWMx duty cycle is: Resolution = 1 / (256 - ARTARR) Note: To get the maximum resolution (1/256), the ARTARR register must be 0. With this maximum resolution, 0% and 100% can be obtained by changing the polarity. Figure 38. PWM Auto-reload Timer Function COUNTER 255 DUTY CYCLE REGISTER (PWMDCRx) AUTO-RELOAD REGISTER (ARTARR) PWMx OUTPUT 000 t WITH OEx=1 AND OPx=0 WITH OEx=1 AND OPx=1 Figure 39. PWM Signal from 0% to 100% Duty Cycle fCOUNTER ARTARR=FDh COUNTER FDh FEh FFh FDh FEh FFh FDh FEh PWMx OUTPUT WITH OEx=1 AND OPx=0 OCRx=FCh OCRx=FDh OCRx=FEh OCRx=FFh t 63/215 ST72F521, ST72521B PWM AUTO-RELOAD TIMER (Cont'd) Output compare and Time base interrupt On overflow, the OVF flag of the ARTCSR register is set and an overflow interrupt request is generated if the overflow interrupt enable bit, OIE, in the ARTCSR register, is set. The OVF flag must be reset by the user software. This interrupt can be used as a time base in the application. External clock and event detector mode Using the fEXT external prescaler input clock, the auto-reload timer can be used as an external clock event detector. In this mode, the ARTARR register is used to select the nEVENT number of events to be counted before setting the OVF flag. nEVENT = 256 - ARTARR Caution: The external clock function is not available in HALT mode. If HALT mode is used in the application, prior to executing the HALT instruction, the counter must be disabled by clearing the TCE bit in the ARTCSR register to avoid spurious counter increments. Figure 40. External Event Detector Example (3 counts) fEXT=fCOUNTER ARTARR=FDh COUNTER FDh FEh FFh FDh FEh FFh FDh OVF ARTCSR READ ARTCSR READ INTERRUPT IF OIE=1 INTERRUPT IF OIE=1 t 64/215 ST72F521, ST72521B PWM AUTO-RELOAD TIMER (Cont'd) Input capture function This mode allows the measurement of external signal pulse widths through ARTICRx registers. Each input capture can generate an interrupt independently on a selected input signal transition. This event is flagged by a set of the corresponding CFx bits of the Input Capture Control/Status register (ARTICCSR). These input capture interrupts are enabled through the CIEx bits of the ARTICCSR register. The active transition (falling or rising edge) is software programmable through the CSx bits of the ARTICCSR register. The read only input capture registers (ARTICRx) are used to latch the auto-reload counter value when a transition is detected on the ARTICx pin (CFx bit set in ARTICCSR register). After fetching the interrupt vector, the CFx flags can be read to identify the interrupt source. Note: After a capture detection, data transfer in the ARTICRx register is inhibited until it is read (clearing the CFx bit). The timer interrupt remains pending while the CFx flag is set when the interrupt is enabled (CIEx bit set). This means, the ARTICRx register has to be read at each capture event to clear the CFx flag. External interrupt capability This mode allows the Input capture capabilities to be used as external interrupt sources. The interrupts are generated on the edge of the ARTICx signal. The edge sensitivity of the external interrupts is programmable (CSx bit of ARTICCSR register) and they are independently enabled through CIEx bits of the ARTICCSR register. After fetching the interrupt vector, the CFx flags can be read to identify the interrupt source. During HALT mode, the external interrupts can be used to wake up the micro (if the CIEx bit is set). The timing resolution is given by auto-reload counter cycle time (1/fCOUNTER). Note: During HALT mode, if both input capture and external clock are enabled, the ARTICRx register value is not guaranteed if the input capture pin and the external clock change simultaneously. Figure 41. Input Capture Timing Diagram fCOUNTER COUNTER 01h 02h 03h 04h 05h 06h 07h INTERRUPT ARTICx PIN CFx FLAG xxh 04h ICRx REGISTER t 65/215 ST72F521, ST72521B PWM AUTO-RELOAD TIMER (Cont'd) 10.3.3 Register Description 0: New transition not yet reached 1: Transition reached CONTROL / STATUS REGISTER (ARTCSR) Read/Write Reset Value: 0000 0000 (00h) 7 EXCL 0 CC2 CC1 CC0 TCE FCRL OIE COUNTER ACCESS REGISTER (ARTCAR) Read/Write Reset Value: 0000 0000 (00h) OVF 7 Bit 7 = EXCL External Clock This bit is set and cleared by software. It selects the input clock for the 7-bit prescaler. 0: CPU clock. 1: External clock. Bit 6:4 = CC[2:0] Counter Clock Control These bits are set and cleared by software. They determine the prescaler division ratio from fINPUT. fCOUNTER fINPUT fINPUT / 2 fINPUT / 4 fINPUT / 8 fINPUT / 16 fINPUT / 32 fINPUT / 64 fINPUT / 128 CA6 CA5 CA4 CA3 CA2 CA1 CA0 Bit 7:0 = CA[7:0] Counter Access Data These bits can be set and cleared either by hardware or by software. The ARTCAR register is used to read or write the auto-reload counter "on the fly" (while it is counting). With fINPUT=8 MHz CC2 CC1 CC0 8 MHz 4 MHz 2 MHz 1 MHz 500 KHz 250 KHz 125 KHz 62.5 KHz 0 0 0 0 1 1 1 1 0 0 1 1 0 0 1 1 0 1 0 1 0 1 0 1 Bit 3 = TCE Timer Counter Enable This bit is set and cleared by software. It puts the timer in the lowest power consumption mode. 0: Counter stopped (prescaler and counter frozen). 1: Counter running. Bit 2 = FCRL Force Counter Re-Load This bit is write-only and any attempt to read it will yield a logical zero. When set, it causes the contents of ARTARR register to be loaded into the counter, and the content of the prescaler register to be cleared in order to initialize the timer before starting to count. Bit 1 = OIE Overflow Interrupt Enable This bit is set and cleared by software. It allows to enable/disable the interrupt which is generated when the OVF bit is set. 0: Overflow Interrupt disable. 1: Overflow Interrupt enable. Bit 0 = OVF Overflow Flag This bit is set by hardware and cleared by software reading the ARTCSR register. It indicates the transition of the counter from FFh to the ARTARR value. 66/215 CA7 0 AUTO-RELOAD REGISTER (ARTARR) Read/Write Reset Value: 0000 0000 (00h) 7 AR7 0 AR6 AR5 AR4 AR3 AR2 AR1 AR0 Bit 7:0 = AR[7:0] Counter Auto-Reload Data These bits are set and cleared by software. They are used to hold the auto-reload value which is automatically loaded in the counter when an overflow occurs. At the same time, the PWM output levels are changed according to the corresponding OPx bit in the PWMCR register. This register has two PWM management functions: - Adjusting the PWM frequency - Setting the PWM duty cycle resolution PWM Frequency vs. Resolution: ARTARR value Resolution 0 [ 0..127 ] [ 128..191 ] [ 192..223 ] [ 224..239 ] 8-bit > 7-bit > 6-bit > 5-bit > 4-bit fPWM Min Max ~0.244-KHz ~0.244-KHz ~0.488-KHz ~0.977-KHz ~1.953-KHz 31.25-KHz 62.5-KHz 125-KHz 250-KHz 500-KHz ST72F521, ST72521B PWM AUTO-RELOAD TIMER (Cont'd) PWM CONTROL REGISTER (PWMCR) Read/Write Reset Value: 0000 0000 (00h) DUTY CYCLE REGISTERS (PWMDCRx) Read/Write Reset Value: 0000 0000 (00h) 7 OE3 OE2 OE1 OE0 OP3 OP2 OP1 0 7 OP0 DC7 Bit 7:4 = OE[3:0] PWM Output Enable These bits are set and cleared by software. They enable or disable the PWM output channels independently acting on the corresponding I/O pin. 0: PWM output disabled. 1: PWM output enabled. Bit 3:0 = OP[3:0] PWM Output Polarity These bits are set and cleared by software. They independently select the polarity of the four PWM output signals. 0 DC6 DC5 DC4 DC3 DC2 DC1 DC0 Bit 7:0 = DC[7:0] Duty Cycle Data These bits are set and cleared by software. A PWMDCRx register is associated with the OCRx register of each PWM channel to determine the second edge location of the PWM signal (the first edge location is common to all channels and given by the ARTARR register). These PWMDCR registers allow the duty cycle to be set independently for each PWM channel. PWMx output level OPx Counter <= OCRx Counter > OCRx 1 0 0 1 0 1 Note: When an OPx bit is modified, the PWMx output signal polarity is immediately reversed. 67/215 ST72F521, ST72521B PWM AUTO-RELOAD TIMER (Cont'd) INPUT CAPTURE CONTROL / STATUS REGISTER (ARTICCSR) Read/Write Reset Value: 0000 0000 (00h) INPUT CAPTURE REGISTERS (ARTICRx) Read only Reset Value: 0000 0000 (00h) 7 7 IC7 0 0 CS2 CS1 CIE2 CIE1 CF2 IC6 IC5 IC4 IC3 IC2 IC1 IC0 CF1 Bit 7:6 = Reserved, always read as 0. Bit 5:4 = CS[2:1] Capture Sensitivity These bits are set and cleared by software. They determine the trigger event polarity on the corresponding input capture channel. 0: Falling edge triggers capture on channel x. 1: Rising edge triggers capture on channel x. Bit 3:2 = CIE[2:1] Capture Interrupt Enable These bits are set and cleared by software. They enable or disable the Input capture channel interrupts independently. 0: Input capture channel x interrupt disabled. 1: Input capture channel x interrupt enabled. Bit 1:0 = CF[2:1] Capture Flag These bits are set by hardware and cleared by software reading the corresponding ARTICRx register. Each CFx bit indicates that an input capture x has occurred. 0: No input capture on channel x. 1: An input capture has occured on channel x. 68/215 0 0 Bit 7:0 = IC[7:0] Input Capture Data These read only bits are set and cleared by hardware. An ARTICRx register contains the 8-bit auto-reload counter value transferred by the input capture channel x event. ST72F521, ST72521B PWM AUTO-RELOAD TIMER (Cont'd) Table 15. PWM Auto-Reload Timer Register Map and Reset Values Address (Hex.) 0073h 0074h 0075h 0076h 0077h 0078h 0079h 007Ah 007Bh 007Ch 007Dh Register Label PWMDCR3 Reset Value PWMDCR2 Reset Value PWMDCR1 Reset Value PWMDCR0 Reset Value PWMCR Reset Value ARTCSR Reset Value ARTCAR Reset Value ARTARR Reset Value 7 6 5 4 3 2 1 0 DC7 0 DC6 0 DC5 0 DC4 0 DC3 0 DC2 0 DC1 0 DC0 0 DC7 0 DC6 0 DC5 0 DC4 0 DC3 0 DC2 0 DC1 0 DC0 0 DC7 0 DC6 0 DC5 0 DC4 0 DC3 0 DC2 0 DC1 0 DC0 0 DC7 0 DC6 0 DC5 0 DC4 0 DC3 0 DC2 0 DC1 0 DC0 0 OE3 0 OE2 0 OE1 0 OE0 0 OP3 0 OP2 0 OP1 0 OP0 0 EXCL 0 CC2 0 CC1 0 CC0 0 TCE 0 FCRL 0 RIE 0 OVF 0 CA7 0 CA6 0 CA5 0 CA4 0 CA3 0 CA2 0 CA1 0 CA0 0 AR7 0 AR6 0 AR5 0 AR4 0 AR3 0 AR2 0 AR1 0 AR0 0 0 0 CS2 0 CS1 0 CIE2 0 CIE1 0 CF2 0 CF1 0 IC7 0 IC6 0 IC5 0 IC4 0 IC3 0 IC2 0 IC1 0 IC0 0 IC7 0 IC6 0 IC5 0 IC4 0 IC3 0 IC2 0 IC1 0 IC0 0 ARTICCSR Reset Value ARTICR1 Reset Value ARTICR2 Reset Value 69/215 ST72F521, ST72521B 10.4 16-BIT TIMER 10.4.1 Introduction The timer consists of a 16-bit free-running counter driven by a programmable prescaler. It may be used for a variety of purposes, including pulse length measurement of up to two input signals (input capture) or generation of up to two output waveforms (output compare and PWM). Pulse lengths and waveform periods can be modulated from a few microseconds to several milliseconds using the timer prescaler and the CPU clock prescaler. Some ST7 devices have two on-chip 16-bit timers. They are completely independent, and do not share any resources. They are synchronized after a MCU reset as long as the timer clock frequencies are not modified. This description covers one or two 16-bit timers. In ST7 devices with two timers, register names are prefixed with TA (Timer A) or TB (Timer B). 10.4.2 Main Features Programmable prescaler: fCPU divided by 2, 4 or 8. Overflow status flag and maskable interrupt External clock input (must be at least 4 times slower than the CPU clock speed) with the choice of active edge 1 or 2 Output Compare functions each with: - 2 dedicated 16-bit registers - 2 dedicated programmable signals - 2 dedicated status flags - 1 dedicated maskable interrupt 1 or 2 Input Capture functions each with: - 2 dedicated 16-bit registers - 2 dedicated active edge selection signals - 2 dedicated status flags - 1 dedicated maskable interrupt Pulse width modulation mode (PWM) One pulse mode Reduced Power Mode 5 alternate functions on I/O ports (ICAP1, ICAP2, OCMP1, OCMP2, EXTCLK)* The Block Diagram is shown in Figure 42. *Note: Some timer pins may not be available (not bonded) in some ST7 devices. Refer to the device pin out description. 70/215 When reading an input signal on a non-bonded pin, the value will always be `1'. 10.4.3 Functional Description 10.4.3.1 Counter The main block of the Programmable Timer is a 16-bit free running upcounter and its associated 16-bit registers. The 16-bit registers are made up of two 8-bit registers called high & low. Counter Register (CR): - Counter High Register (CHR) is the most significant byte (MS Byte). - Counter Low Register (CLR) is the least significant byte (LS Byte). Alternate Counter Register (ACR) - Alternate Counter High Register (ACHR) is the most significant byte (MS Byte). - Alternate Counter Low Register (ACLR) is the least significant byte (LS Byte). These two read-only 16-bit registers contain the same value but with the difference that reading the ACLR register does not clear the TOF bit (Timer overflow flag), located in the Status register, (SR), (see note at the end of paragraph titled 16-bit read sequence). Writing in the CLR register or ACLR register resets the free running counter to the FFFCh value. Both counters have a reset value of FFFCh (this is the only value which is reloaded in the 16-bit timer). The reset value of both counters is also FFFCh in One Pulse mode and PWM mode. The timer clock depends on the clock control bits of the CR2 register, as illustrated in Table 16 Clock Control Bits. The value in the counter register repeats every 131072, 262144 or 524288 CPU clock cycles depending on the CC[1:0] bits. The timer frequency can be fCPU/2, fCPU/4, fCPU/8 or an external frequency. ST72F521, ST72521B 16-BIT TIMER (Cont'd) Figure 42. Timer Block Diagram ST7 INTERNAL BUS fCPU MCU-PERIPHERAL INTERFACE 8 low 8 8 8 low 8 high 8 low 8 high EXEDG 8 low high 8 high 8-bit buffer low 8 high 16 1/2 1/4 1/8 OUTPUT COMPARE REGISTER 2 OUTPUT COMPARE REGISTER 1 COUNTER REGISTER ALTERNATE COUNTER REGISTER EXTCLK pin INPUT CAPTURE REGISTER 1 INPUT CAPTURE REGISTER 2 16 16 16 CC[1:0] TIMER INTERNAL BUS 16 16 OVERFLOW DETECT CIRCUIT OUTPUT COMPARE CIRCUIT 6 ICF1 OCF1 TOF ICF2 OCF2 TIMD 0 EDGE DETECT CIRCUIT1 ICAP1 pin EDGE DETECT CIRCUIT2 ICAP2 pin LATCH1 OCMP1 pin LATCH2 OCMP2 pin 0 (Control/Status Register) CSR ICIE OCIE TOIE FOLV2 FOLV1 OLVL2 IEDG1 OLVL1 (Control Register 1) CR1 OC1E OC2E OPM PWM CC1 CC0 IEDG2 EXEDG (Control Register 2) CR2 (See note) TIMER INTERRUPT Note: If IC, OC and TO interrupt requests have separate vectors then the last OR is not present (See device Interrupt Vector Table) 71/215 ST72F521, ST72521B 16-BIT TIMER (Cont'd) 16-bit read sequence: (from either the Counter Register or the Alternate Counter Register). Beginning of the sequence At t0 Read MS Byte LS Byte is buffered Other instructions Read At t0 +t LS Byte Returns the buffered LS Byte value at t0 Sequence completed The user must read the MS Byte first, then the LS Byte value is buffered automatically. This buffered value remains unchanged until the 16-bit read sequence is completed, even if the user reads the MS Byte several times. After a complete reading sequence, if only the CLR register or ACLR register are read, they return the LS Byte of the count value at the time of the read. Whatever the timer mode used (input capture, output compare, one pulse mode or PWM mode) an overflow occurs when the counter rolls over from FFFFh to 0000h then: - The TOF bit of the SR register is set. - A timer interrupt is generated if: - TOIE bit of the CR1 register is set and - I bit of the CC register is cleared. If one of these conditions is false, the interrupt remains pending to be issued as soon as they are both true. 72/215 Clearing the overflow interrupt request is done in two steps: 1. Reading the SR register while the TOF bit is set. 2. An access (read or write) to the CLR register. Notes: The TOF bit is not cleared by accesses to ACLR register. The advantage of accessing the ACLR register rather than the CLR register is that it allows simultaneous use of the overflow function and reading the free running counter at random times (for example, to measure elapsed time) without the risk of clearing the TOF bit erroneously. The timer is not affected by WAIT mode. In HALT mode, the counter stops counting until the mode is exited. Counting then resumes from the previous count (MCU awakened by an interrupt) or from the reset count (MCU awakened by a Reset). 10.4.3.2 External Clock The external clock (where available) is selected if CC0=1 and CC1=1 in the CR2 register. The status of the EXEDG bit in the CR2 register determines the type of level transition on the external clock pin EXTCLK that will trigger the free running counter. The counter is synchronized with the falling edge of the internal CPU clock. A minimum of four falling edges of the CPU clock must occur between two consecutive active edges of the external clock; thus the external clock frequency must be less than a quarter of the CPU clock frequency. ST72F521, ST72521B 16-BIT TIMER (Cont'd) Figure 43. Counter Timing Diagram, internal clock divided by 2 CPU CLOCK INTERNAL RESET TIMER CLOCK FFFD FFFE FFFF 0000 COUNTER REGISTER 0001 0002 0003 TIMER OVERFLOW FLAG (TOF) Figure 44. Counter Timing Diagram, internal clock divided by 4 CPU CLOCK INTERNAL RESET TIMER CLOCK COUNTER REGISTER FFFC FFFD 0000 0001 TIMER OVERFLOW FLAG (TOF) Figure 45. Counter Timing Diagram, internal clock divided by 8 CPU CLOCK INTERNAL RESET TIMER CLOCK COUNTER REGISTER FFFC FFFD 0000 TIMER OVERFLOW FLAG (TOF) Note: The MCU is in reset state when the internal reset signal is high, when it is low the MCU is running. 73/215 ST72F521, ST72521B 16-BIT TIMER (Cont'd) 10.4.3.3 Input Capture In this section, the index, i, may be 1 or 2 because there are 2 input capture functions in the 16-bit timer. The two 16-bit input capture registers (IC1R and IC2R) are used to latch the value of the free running counter after a transition is detected on the ICAPi pin (see figure 5). ICiR MS Byte ICiHR LS Byte ICiLR ICiR register is a read-only register. The active transition is software programmable through the IEDGi bit of Control Registers (CRi). Timing resolution is one count of the free running counter: (fCPU/CC[1:0]). Procedure: To use the input capture function select the following in the CR2 register: - Select the timer clock (CC[1:0]) (see Table 16 Clock Control Bits). - Select the edge of the active transition on the ICAP2 pin with the IEDG2 bit (the ICAP2 pin must be configured as floating input or input with pull-up without interrupt if this configuration is available). And select the following in the CR1 register: - Set the ICIE bit to generate an interrupt after an input capture coming from either the ICAP1 pin or the ICAP2 pin - Select the edge of the active transition on the ICAP1 pin with the IEDG1 bit (the ICAP1pin must be configured as floating input or input with pullup without interrupt if this configuration is available). 74/215 When an input capture occurs: - ICFi bit is set. - The ICiR register contains the value of the free running counter on the active transition on the ICAPi pin (see Figure 47). - A timer interrupt is generated if the ICIE bit is set and the I bit is cleared in the CC register. Otherwise, the interrupt remains pending until both conditions become true. Clearing the Input Capture interrupt request (i.e. clearing the ICFi bit) is done in two steps: 1. Reading the SR register while the ICFi bit is set. 2. An access (read or write) to the ICiLR register. Notes: 1. After reading the ICiHR register, transfer of input capture data is inhibited and ICFi will never be set until the ICiLR register is also read. 2. The ICiR register contains the free running counter value which corresponds to the most recent input capture. 3. The 2 input capture functions can be used together even if the timer also uses the 2 output compare functions. 4. In One pulse Mode and PWM mode only Input Capture 2 can be used. 5. The alternate inputs (ICAP1 & ICAP2) are always directly connected to the timer. So any transitions on these pins activates the input capture function. Moreover if one of the ICAPi pins is configured as an input and the second one as an output, an interrupt can be generated if the user toggles the output pin and if the ICIE bit is set. This can be avoided if the input capture function i is disabled by reading the ICiHR (see note 1). 6. The TOF bit can be used with interrupt generation in order to measure events that go beyond the timer range (FFFFh). ST72F521, ST72521B 16-BIT TIMER (Cont'd) Figure 46. Input Capture Block Diagram ICAP1 pin ICAP2 pin (Control Register 1) CR1 EDGE DETECT CIRCUIT2 EDGE DETECT CIRCUIT1 ICIE IEDG1 (Status Register) SR IC2R Register IC1R Register ICF1 ICF2 0 0 0 (Control Register 2) CR2 16-BIT 16-BIT FREE RUNNING COUNTER CC1 CC0 IEDG2 Figure 47. Input Capture Timing Diagram TIMER CLOCK COUNTER REGISTER FF01 FF02 FF03 ICAPi PIN ICAPi FLAG ICAPi REGISTER FF03 Note: The rising edge is the active edge. 75/215 ST72F521, ST72521B 16-BIT TIMER (Cont'd) 10.4.3.4 Output Compare In this section, the index, i, may be 1 or 2 because there are 2 output compare functions in the 16-bit timer. This function can be used to control an output waveform or indicate when a period of time has elapsed. When a match is found between the Output Compare register and the free running counter, the output compare function: - Assigns pins with a programmable value if the OCiE bit is set - Sets a flag in the status register - Generates an interrupt if enabled Two 16-bit registers Output Compare Register 1 (OC1R) and Output Compare Register 2 (OC2R) contain the value to be compared to the counter register each timer clock cycle. OCiR MS Byte OCiHR LS Byte OCiLR These registers are readable and writable and are not affected by the timer hardware. A reset event changes the OCiR value to 8000h. Timing resolution is one count of the free running counter: (fCPU/CC[1:0]). Procedure: To use the output compare function, select the following in the CR2 register: - Set the OCiE bit if an output is needed then the OCMPi pin is dedicated to the output compare i signal. - Select the timer clock (CC[1:0]) (see Table 16 Clock Control Bits). And select the following in the CR1 register: - Select the OLVLi bit to applied to the OCMPi pins after the match occurs. - Set the OCIE bit to generate an interrupt if it is needed. When a match is found between OCRi register and CR register: - OCFi bit is set. 76/215 - The OCMPi pin takes OLVLi bit value (OCMPi pin latch is forced low during reset). - A timer interrupt is generated if the OCIE bit is set in the CR1 register and the I bit is cleared in the CC register (CC). The OCiR register value required for a specific timing application can be calculated using the following formula: OCiR = t * fCPU PRESC Where: t = Output compare period (in seconds) fCPU = CPU clock frequency (in hertz) = Timer prescaler factor (2, 4 or 8 dePRESC pending on CC[1:0] bits, see Table 16 Clock Control Bits) If the timer clock is an external clock, the formula is: OCiR = t * fEXT Where: t = Output compare period (in seconds) = External timer clock frequency (in hertz) fEXT Clearing the output compare interrupt request (i.e. clearing the OCFi bit) is done by: 1. Reading the SR register while the OCFi bit is set. 2. An access (read or write) to the OCiLR register. The following procedure is recommended to prevent the OCFi bit from being set between the time it is read and the write to the OCiR register: - Write to the OCiHR register (further compares are inhibited). - Read the SR register (first step of the clearance of the OCFi bit, which may be already set). - Write to the OCiLR register (enables the output compare function and clears the OCFi bit). ST72F521, ST72521B 16-BIT TIMER (Cont'd) Notes: 1. After a processor write cycle to the OCiHR register, the output compare function is inhibited until the OCiLR register is also written. 2. If the OCiE bit is not set, the OCMPi pin is a general I/O port and the OLVLi bit will not appear when a match is found but an interrupt could be generated if the OCIE bit is set. 3. When the timer clock is fCPU/2, OCFi and OCMPi are set while the counter value equals the OCiR register value (see Figure 49 on page 78). This behaviour is the same in OPM or PWM mode. When the timer clock is fCPU/4, fCPU/8 or in external clock mode, OCFi and OCMPi are set while the counter value equals the OCiR register value plus 1 (see Figure 50 on page 78). 4. The output compare functions can be used both for generating external events on the OCMPi pins even if the input capture mode is also used. 5. The value in the 16-bit OCiR register and the OLVi bit should be changed after each successful comparison in order to control an output waveform or establish a new elapsed timeout. Forced Compare Output capability When the FOLVi bit is set by software, the OLVLi bit is copied to the OCMPi pin. The OLVi bit has to be toggled in order to toggle the OCMPi pin when it is enabled (OCiE bit=1). The OCFi bit is then not set by hardware, and thus no interrupt request is generated. The FOLVLi bits have no effect in both one pulse mode and PWM mode. Figure 48. Output Compare Block Diagram 16 BIT FREE RUNNING COUNTER OC1E OC2E CC1 CC0 (Control Register 2) CR2 16-bit (Control Register 1) CR1 OUTPUT COMPARE CIRCUIT 16-bit OCIE FOLV2 FOLV1 OLVL2 OLVL1 16-bit Latch 1 Latch 2 OC1R Register OCF1 OCF2 0 0 OCMP1 Pin OCMP2 Pin 0 OC2R Register (Status Register) SR 77/215 ST72F521, ST72521B 16-BIT TIMER (Cont'd) Figure 49. Output Compare Timing Diagram, fTIMER =fCPU/2 INTERNAL CPU CLOCK TIMER CLOCK COUNTER REGISTER 2ECF 2ED0 2ED1 2ED2 2ED3 2ED4 OUTPUT COMPARE REGISTER i (OCRi) 2ED3 OUTPUT COMPARE FLAG i (OCFi) OCMPi PIN (OLVLi=1) Figure 50. Output Compare Timing Diagram, fTIMER =fCPU/4 INTERNAL CPU CLOCK TIMER CLOCK COUNTER REGISTER OUTPUT COMPARE REGISTER i (OCRi) COMPARE REGISTER i LATCH OUTPUT COMPARE FLAG i (OCFi) OCMPi PIN (OLVLi=1) 78/215 2ECF 2ED0 2ED1 2ED2 2ED3 2ED4 2ED3 ST72F521, ST72521B 16-BIT TIMER (Cont'd) 10.4.3.5 One Pulse Mode One Pulse mode enables the generation of a pulse when an external event occurs. This mode is selected via the OPM bit in the CR2 register. The one pulse mode uses the Input Capture1 function and the Output Compare1 function. Procedure: To use one pulse mode: 1. Load the OC1R register with the value corresponding to the length of the pulse (see the formula in the opposite column). 2. Select the following in the CR1 register: - Using the OLVL1 bit, select the level to be applied to the OCMP1 pin after the pulse. - Using the OLVL2 bit, select the level to be applied to the OCMP1 pin during the pulse. - Select the edge of the active transition on the ICAP1 pin with the IEDG1 bit (the ICAP1 pin must be configured as floating input). 3. Select the following in the CR2 register: - Set the OC1E bit, the OCMP1 pin is then dedicated to the Output Compare 1 function. - Set the OPM bit. - Select the timer clock CC[1:0] (see Table 16 Clock Control Bits). One pulse mode cycle When event occurs on ICAP1 ICR1 = Counter OCMP1 = OLVL2 Counter is reset to FFFCh ICF1 bit is set When Counter = OC1R OCMP1 = OLVL1 Then, on a valid event on the ICAP1 pin, the counter is initialized to FFFCh and OLVL2 bit is loaded on the OCMP1 pin, the ICF1 bit is set and the value FFFDh is loaded in the IC1R register. Because the ICF1 bit is set when an active edge occurs, an interrupt can be generated if the ICIE bit is set. Clearing the Input Capture interrupt request (i.e. clearing the ICFi bit) is done in two steps: 1. Reading the SR register while the ICFi bit is set. 2. An access (read or write) to the ICiLR register. The OC1R register value required for a specific timing application can be calculated using the following formula: OCiR Value = t * fCPU -5 PRESC Where: t = Pulse period (in seconds) fCPU = CPU clock frequency (in hertz) PRESC = Timer prescaler factor (2, 4 or 8 depending on the CC[1:0] bits, see Table 16 Clock Control Bits) If the timer clock is an external clock the formula is: OCiR = t * fEXT -5 Where: t = Pulse period (in seconds) = External timer clock frequency (in hertz) fEXT When the value of the counter is equal to the value of the contents of the OC1R register, the OLVL1 bit is output on the OCMP1 pin, (See Figure 51). Notes: 1. The OCF1 bit cannot be set by hardware in one pulse mode but the OCF2 bit can generate an Output Compare interrupt. 2. When the Pulse Width Modulation (PWM) and One Pulse Mode (OPM) bits are both set, the PWM mode is the only active one. 3. If OLVL1=OLVL2 a continuous signal will be seen on the OCMP1 pin. 4. The ICAP1 pin can not be used to perform input capture. The ICAP2 pin can be used to perform input capture (ICF2 can be set and IC2R can be loaded) but the user must take care that the counter is reset each time a valid edge occurs on the ICAP1 pin and ICF1 can also generates interrupt if ICIE is set. 5. When one pulse mode is used OC1R is dedicated to this mode. Nevertheless OC2R and OCF2 can be used to indicate a period of time has been elapsed but cannot generate an output waveform because the level OLVL2 is dedicated to the one pulse mode. 79/215 ST72F521, ST72521B 16-BIT TIMER (Cont'd) Figure 51. One Pulse Mode Timing Example COUNTER 2ED3 01F8 IC1R 01F8 FFFC FFFD FFFE 2ED0 2ED1 2ED2 FFFC FFFD 2ED3 ICAP1 OLVL2 OCMP1 OLVL1 OLVL2 compare1 Note: IEDG1=1, OC1R=2ED0h, OLVL1=0, OLVL2=1 Figure 52. Pulse Width Modulation Mode Timing Example with 2 Output Compare Functions COUNTER 34E2 FFFC FFFD FFFE 2ED0 2ED1 2ED2 OLVL2 OCMP1 compare2 OLVL1 compare1 34E2 FFFC OLVL2 compare2 Note: OC1R=2ED0h, OC2R=34E2, OLVL1=0, OLVL2= 1 Note: On timers with only 1 Output Compare register, a fixed frequency PWM signal can be generated using the output compare and the counter overflow to define the pulse length. 80/215 ST72F521, ST72521B 16-BIT TIMER (Cont'd) 10.4.3.6 Pulse Width Modulation Mode Pulse Width Modulation (PWM) mode enables the generation of a signal with a frequency and pulse length determined by the value of the OC1R and OC2R registers. Pulse Width Modulation mode uses the complete Output Compare 1 function plus the OC2R register, and so this functionality can not be used when PWM mode is activated. In PWM mode, double buffering is implemented on the output compare registers. Any new values written in the OC1R and OC2R registers are taken into account only at the end of the PWM period (OC2) to avoid spikes on the PWM output pin (OCMP1). Procedure To use pulse width modulation mode: 1. Load the OC2R register with the value corresponding to the period of the signal using the formula in the opposite column. 2. Load the OC1R register with the value corresponding to the period of the pulse if (OLVL1=0 and OLVL2=1) using the formula in the opposite column. 3. Select the following in the CR1 register: - Using the OLVL1 bit, select the level to be applied to the OCMP1 pin after a successful comparison with the OC1R register. - Using the OLVL2 bit, select the level to be applied to the OCMP1 pin after a successful comparison with the OC2R register. 4. Select the following in the CR2 register: - Set OC1E bit: the OCMP1 pin is then dedicated to the output compare 1 function. - Set the PWM bit. - Select the timer clock (CC[1:0]) (see Table 16 Clock Control Bits). Pulse Width Modulation cycle When Counter = OC1R When Counter = OC2R OCMP1 = OLVL1 OCMP1 = OLVL2 Counter is reset to FFFCh If OLVL1=1 and OLVL2=0 the length of the positive pulse is the difference between the OC2R and OC1R registers. If OLVL1=OLVL2 a continuous signal will be seen on the OCMP1 pin. The OCiR register value required for a specific timing application can be calculated using the following formula: OCiR Value = t * fCPU -5 PRESC Where: t = Signal or pulse period (in seconds) fCPU = CPU clock frequency (in hertz) PRESC = Timer prescaler factor (2, 4 or 8 depending on CC[1:0] bits, see Table 16 Clock Control Bits) If the timer clock is an external clock the formula is: OCiR = t * fEXT -5 Where: t = Signal or pulse period (in seconds) fEXT = External timer clock frequency (in hertz) The Output Compare 2 event causes the counter to be initialized to FFFCh (See Figure 52) Notes: 1. After a write instruction to the OCiHR register, the output compare function is inhibited until the OCiLR register is also written. 2. The OCF1 and OCF2 bits cannot be set by hardware in PWM mode therefore the Output Compare interrupt is inhibited. 3. The ICF1 bit is set by hardware when the counter reaches the OC2R value and can produce a timer interrupt if the ICIE bit is set and the I bit is cleared. 4. In PWM mode the ICAP1 pin can not be used to perform input capture because it is disconnected to the timer. The ICAP2 pin can be used to perform input capture (ICF2 can be set and IC2R can be loaded) but the user must take care that the counter is reset each period and ICF1 can also generates interrupt if ICIE is set. 5. When the Pulse Width Modulation (PWM) and One Pulse Mode (OPM) bits are both set, the PWM mode is the only active one. ICF1 bit is set 81/215 ST72F521, ST72521B 16-BIT TIMER (Cont'd) 10.4.4 Low Power Modes Mode WAIT HALT Description No effect on 16-bit Timer. Timer interrupts cause the device to exit from WAIT mode. 16-bit Timer registers are frozen. In HALT mode, the counter stops counting until Halt mode is exited. Counting resumes from the previous count when the MCU is woken up by an interrupt with "exit from HALT mode" capability or from the counter reset value when the MCU is woken up by a RESET. If an input capture event occurs on the ICAPi pin, the input capture detection circuitry is armed. Consequently, when the MCU is woken up by an interrupt with "exit from HALT mode" capability, the ICFi bit is set, and the counter value present when exiting from HALT mode is captured into the ICiR register. 10.4.5 Interrupts Event Flag Interrupt Event Input Capture 1 event/Counter reset in PWM mode Input Capture 2 event Output Compare 1 event (not available in PWM mode) Output Compare 2 event (not available in PWM mode) Timer Overflow event ICF1 ICF2 OCF1 OCF2 TOF Enable Control Bit ICIE OCIE TOIE Exit from Wait Yes Yes Yes Yes Yes Exit from Halt No No No No No Note: The 16-bit Timer interrupt events are connected to the same interrupt vector (see Interrupts chapter). These events generate an interrupt if the corresponding Enable Control Bit is set and the interrupt mask in the CC register is reset (RIM instruction). 10.4.6 Summary of Timer modes MODES Input Capture (1 and/or 2) Output Compare (1 and/or 2) One Pulse Mode PWM Mode Input Capture 1 Yes Yes No No TIMER RESOURCES Input Capture 2 Output Compare 1 Output Compare 2 Yes Yes Yes Yes Yes Yes No Partially 2) Not Recommended1) 3) Not Recommended No No 1) See note 4 in Section 10.4.3.5 One Pulse Mode 2) See note 5 in Section 10.4.3.5 One Pulse Mode 3) See note 4 in Section 10.4.3.6 Pulse Width Modulation Mode 82/215 ST72F521, ST72521B 16-BIT TIMER (Cont'd) 10.4.7 Register Description Each Timer is associated with three control and status registers, and with six pairs of data registers (16-bit values) relating to the two input captures, the two output compares, the counter and the alternate counter. CONTROL REGISTER 1 (CR1) Read/Write Reset Value: 0000 0000 (00h) 7 0 Bit 4 = FOLV2 Forced Output Compare 2. This bit is set and cleared by software. 0: No effect on the OCMP2 pin. 1: Forces the OLVL2 bit to be copied to the OCMP2 pin, if the OC2E bit is set and even if there is no successful comparison. Bit 3 = FOLV1 Forced Output Compare 1. This bit is set and cleared by software. 0: No effect on the OCMP1 pin. 1: Forces OLVL1 to be copied to the OCMP1 pin, if the OC1E bit is set and even if there is no successful comparison. ICIE OCIE TOIE FOLV2 FOLV1 OLVL2 IEDG1 OLVL1 Bit 7 = ICIE Input Capture Interrupt Enable. 0: Interrupt is inhibited. 1: A timer interrupt is generated whenever the ICF1 or ICF2 bit of the SR register is set. Bit 6 = OCIE Output Compare Interrupt Enable. 0: Interrupt is inhibited. 1: A timer interrupt is generated whenever the OCF1 or OCF2 bit of the SR register is set. Bit 5 = TOIE Timer Overflow Interrupt Enable. 0: Interrupt is inhibited. 1: A timer interrupt is enabled whenever the TOF bit of the SR register is set. Bit 2 = OLVL2 Output Level 2. This bit is copied to the OCMP2 pin whenever a successful comparison occurs with the OC2R register and OCxE is set in the CR2 register. This value is copied to the OCMP1 pin in One Pulse Mode and Pulse Width Modulation mode. Bit 1 = IEDG1 Input Edge 1. This bit determines which type of level transition on the ICAP1 pin will trigger the capture. 0: A falling edge triggers the capture. 1: A rising edge triggers the capture. Bit 0 = OLVL1 Output Level 1. The OLVL1 bit is copied to the OCMP1 pin whenever a successful comparison occurs with the OC1R register and the OC1E bit is set in the CR2 register. 83/215 ST72F521, ST72521B 16-BIT TIMER (Cont'd) CONTROL REGISTER 2 (CR2) Read/Write Reset Value: 0000 0000 (00h) 7 0 OC1E OC2E OPM PWM CC1 CC0 IEDG2 EXEDG Bit 7 = OC1E Output Compare 1 Pin Enable. This bit is used only to output the signal from the timer on the OCMP1 pin (OLV1 in Output Compare mode, both OLV1 and OLV2 in PWM and one-pulse mode). Whatever the value of the OC1E bit, the Output Compare 1 function of the timer remains active. 0: OCMP1 pin alternate function disabled (I/O pin free for general-purpose I/O). 1: OCMP1 pin alternate function enabled. Bit 6 = OC2E Output Compare 2 Pin Enable. This bit is used only to output the signal from the timer on the OCMP2 pin (OLV2 in Output Compare mode). Whatever the value of the OC2E bit, the Output Compare 2 function of the timer remains active. 0: OCMP2 pin alternate function disabled (I/O pin free for general-purpose I/O). 1: OCMP2 pin alternate function enabled. Bit 5 = OPM One Pulse Mode. 0: One Pulse Mode is not active. 1: One Pulse Mode is active, the ICAP1 pin can be used to trigger one pulse on the OCMP1 pin; the active transition is given by the IEDG1 bit. The length of the generated pulse depends on the contents of the OC1R register. 84/215 Bit 4 = PWM Pulse Width Modulation. 0: PWM mode is not active. 1: PWM mode is active, the OCMP1 pin outputs a programmable cyclic signal; the length of the pulse depends on the value of OC1R register; the period depends on the value of OC2R register. Bit 3, 2 = CC[1:0] Clock Control. The timer clock mode depends on these bits: Table 16. Clock Control Bits Timer Clock fCPU / 4 fCPU / 2 fCPU / 8 External Clock (where available) CC1 0 0 1 CC0 0 1 0 1 1 Note: If the external clock pin is not available, programming the external clock configuration stops the counter. Bit 1 = IEDG2 Input Edge 2. This bit determines which type of level transition on the ICAP2 pin will trigger the capture. 0: A falling edge triggers the capture. 1: A rising edge triggers the capture. Bit 0 = EXEDG External Clock Edge. This bit determines which type of level transition on the external clock pin EXTCLK will trigger the counter register. 0: A falling edge triggers the counter register. 1: A rising edge triggers the counter register. ST72F521, ST72521B 16-BIT TIMER (Cont'd) CONTROL/STATUS REGISTER (CSR) Read/Write (bits 7:3 read only) Reset Value: xxxx x0xx (xxh) Note: Reading or writing the ACLR register does not clear TOF. 7 ICF1 0 OCF1 TOF ICF2 OCF2 TIMD 0 0 Bit 7 = ICF1 Input Capture Flag 1. 0: No input capture (reset value). 1: An input capture has occurred on the ICAP1 pin or the counter has reached the OC2R value in PWM mode. To clear this bit, first read the SR register, then read or write the low byte of the IC1R (IC1LR) register. Bit 6 = OCF1 Output Compare Flag 1. 0: No match (reset value). 1: The content of the free running counter has matched the content of the OC1R register. To clear this bit, first read the SR register, then read or write the low byte of the OC1R (OC1LR) register. Bit 5 = TOF Timer Overflow Flag. 0: No timer overflow (reset value). 1: The free running counter rolled over from FFFFh to 0000h. To clear this bit, first read the SR register, then read or write the low byte of the CR (CLR) register. Bit 4 = ICF2 Input Capture Flag 2. 0: No input capture (reset value). 1: An input capture has occurred on the ICAP2 pin. To clear this bit, first read the SR register, then read or write the low byte of the IC2R (IC2LR) register. Bit 3 = OCF2 Output Compare Flag 2. 0: No match (reset value). 1: The content of the free running counter has matched the content of the OC2R register. To clear this bit, first read the SR register, then read or write the low byte of the OC2R (OC2LR) register. Bit 2 = TIMD Timer disable. This bit is set and cleared by software. When set, it freezes the timer prescaler and counter and disabled the output functions (OCMP1 and OCMP2 pins) to reduce power consumption. Access to the timer registers is still available, allowing the timer configuration to be changed, or the counter reset, while it is disabled. 0: Timer enabled 1: Timer prescaler, counter and outputs disabled Bits 1:0 = Reserved, must be kept cleared. 85/215 ST72F521, ST72521B 16-BIT TIMER (Cont'd) INPUT CAPTURE 1 HIGH REGISTER (IC1HR) Read Only Reset Value: Undefined This is an 8-bit read only register that contains the high part of the counter value (transferred by the input capture 1 event). OUTPUT COMPARE 1 HIGH REGISTER (OC1HR) Read/Write Reset Value: 1000 0000 (80h) This is an 8-bit register that contains the high part of the value to be compared to the CHR register. 7 0 7 0 MSB LSB MSB LSB INPUT CAPTURE 1 LOW REGISTER (IC1LR) Read Only Reset Value: Undefined This is an 8-bit read only register that contains the low part of the counter value (transferred by the input capture 1 event). OUTPUT COMPARE 1 LOW REGISTER (OC1LR) Read/Write Reset Value: 0000 0000 (00h) This is an 8-bit register that contains the low part of the value to be compared to the CLR register. 7 0 7 0 MSB LSB MSB LSB 86/215 ST72F521, ST72521B 16-BIT TIMER (Cont'd) OUTPUT COMPARE 2 HIGH REGISTER (OC2HR) Read/Write Reset Value: 1000 0000 (80h) This is an 8-bit register that contains the high part of the value to be compared to the CHR register. ALTERNATE COUNTER HIGH REGISTER (ACHR) Read Only Reset Value: 1111 1111 (FFh) This is an 8-bit register that contains the high part of the counter value. 7 0 7 0 MSB LSB MSB LSB OUTPUT COMPARE 2 LOW REGISTER (OC2LR) Read/Write Reset Value: 0000 0000 (00h) This is an 8-bit register that contains the low part of the value to be compared to the CLR register. 7 0 MSB LSB COUNTER HIGH REGISTER (CHR) Read Only Reset Value: 1111 1111 (FFh) This is an 8-bit register that contains the high part of the counter value. 7 0 MSB LSB COUNTER LOW REGISTER (CLR) Read Only Reset Value: 1111 1100 (FCh) This is an 8-bit register that contains the low part of the counter value. A write to this register resets the counter. An access to this register after accessing the CSR register clears the TOF bit. 7 0 MSB LSB ALTERNATE COUNTER LOW REGISTER (ACLR) Read Only Reset Value: 1111 1100 (FCh) This is an 8-bit register that contains the low part of the counter value. A write to this register resets the counter. An access to this register after an access to CSR register does not clear the TOF bit in the CSR register. 7 0 MSB LSB INPUT CAPTURE 2 HIGH REGISTER (IC2HR) Read Only Reset Value: Undefined This is an 8-bit read only register that contains the high part of the counter value (transferred by the Input Capture 2 event). 7 0 MSB LSB INPUT CAPTURE 2 LOW REGISTER (IC2LR) Read Only Reset Value: Undefined This is an 8-bit read only register that contains the low part of the counter value (transferred by the Input Capture 2 event). 7 0 MSB LSB 87/215 ST72F521, ST72521B 16-BIT TIMER (Cont'd) Table 17. 16-Bit Timer Register Map and Reset Values Address (Hex.) Register Label 7 6 5 4 3 2 1 0 Timer A: 32 Timer B: 42 Timer A: 31 Timer B: 41 Timer A: 33 Timer B: 43 Timer A: 34 Timer B: 44 Timer A: 35 Timer B: 45 Timer A: 36 Timer B: 46 Timer A: 37 Timer B: 47 Timer A: 3E Timer B: 4E Timer A: 3F Timer B: 4F Timer A: 38 Timer B: 48 Timer A: 39 Timer B: 49 Timer A: 3A Timer B: 4A Timer A: 3B Timer B: 4B Timer A: 3C Timer B: 4C Timer A: 3D Timer B: 4D CR1 Reset Value CR2 Reset Value CSR Reset Value IC1HR Reset Value IC1LR Reset Value OC1HR Reset Value OC1LR Reset Value OC2HR Reset Value OC2LR Reset Value CHR Reset Value CLR Reset Value ACHR Reset Value ACLR Reset Value IC2HR Reset Value IC2LR Reset Value ICIE 0 OC1E 0 ICF1 x MSB x MSB x MSB 1 MSB 0 MSB 1 MSB 0 MSB 1 MSB 1 MSB 1 MSB 1 MSB x MSB x OCIE 0 OC2E 0 OCF1 x TOIE 0 OPM 0 TOF x FOLV2 0 PWM 0 ICF2 x FOLV1 0 CC1 0 OCF2 x OLVL2 0 CC0 0 TIMD 0 IEDG1 0 IEDG2 0 x x x x x x x x x x x x x 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 0 1 1 1 1 1 1 1 1 1 1 1 0 x x x x x x x x x x x x OLVL1 0 EXEDG 0 x LSB x LSB x LSB 0 LSB 0 LSB 0 LSB 0 LSB 1 LSB 0 LSB 1 LSB 0 LSB x LSB x Related Documentation AN 973: SCI software communications using 16bit timer AN 974: Real Time Clock with ST7 Timer Output Compare AN 976: Driving a buzzer through the ST7 Timer PWM function 88/215 AN1041: Using ST7 PWM signal to generate analog input (sinusoid) AN1046: UART emulation software AN1078: PWM duty cycle switch implementing true 0 or 100 per cent duty cycle AN1504: Starting a PWM signal directly at high level using the ST7 16-Bit timer ST72F521, ST72521B 10.5 SERIAL PERIPHERAL INTERFACE (SPI) 10.5.1 Introduction The Serial Peripheral Interface (SPI) allows fullduplex, synchronous, serial communication with external devices. An SPI system may consist of a master and one or more slaves however the SPI interface can not be a master in a multi-master system. 10.5.2 Main Features Full duplex synchronous transfers (on 3 lines) Simplex synchronous transfers (on 2 lines) Master or slave operation Six master mode frequencies (fCPU/4 max.) fCPU/2 max. slave mode frequency (see note) SS Management by software or hardware Programmable clock polarity and phase End of transfer interrupt flag Write collision, Master Mode Fault and Overrun flags Note: In slave mode, continuous transmission is not possible at maximum frequency due to the software overhead for clearing status flags and to initiate the next transmission sequence. 10.5.3 General Description Figure 53 shows the serial peripheral interface (SPI) block diagram. There are 3 registers: - SPI Control Register (SPICR) - SPI Control/Status Register (SPICSR) - SPI Data Register (SPIDR) The SPI is connected to external devices through 4 pins: - MISO: Master In / Slave Out data - MOSI: Master Out / Slave In data - SCK: Serial Clock out by SPI masters and input by SPI slaves Figure 53. Serial Peripheral Interface Block Diagram Data/Address Bus SPIDR Read Interrupt request Read Buffer MOSI MISO 8-Bit Shift Register SPICSR 7 SPIF WCOL OVR MODF SOD bit 0 SOD SSM 0 SSI Write SS SPI STATE CONTROL SCK 7 SPIE 1 0 SPICR 0 SPE SPR2 MSTR CPOL CPHA SPR1 SPR0 MASTER CONTROL SERIAL CLOCK GENERATOR SS 89/215 ST72F521, ST72521B SERIAL PERIPHERAL INTERFACE (Cont'd) - SS: Slave select: This input signal acts as a `chip select' to let the SPI master communicate with slaves individually and to avoid contention on the data lines. Slave SS inputs can be driven by standard I/O ports on the master MCU. 10.5.3.1 Functional Description A basic example of interconnections between a single master and a single slave is illustrated in Figure 54. The MOSI pins are connected together and the MISO pins are connected together. In this way data is transferred serially between master and slave (most significant bit first). The communication is always initiated by the master. When the master device transmits data to a slave device via MOSI pin, the slave device responds by sending data to the master device via the MISO pin. This implies full duplex communication with both data out and data in synchronized with the same clock signal (which is provided by the master device via the SCK pin). To use a single data line, the MISO and MOSI pins must be connected at each node ( in this case only simplex communication is possible). Four possible data/clock timing relationships may be chosen (see Figure 57) but master and slave must be programmed with the same timing mode. Figure 54. Single Master/ Single Slave Application SLAVE MASTER MSBit LSBit 8-BIT SHIFT REGISTER SPI CLOCK GENERATOR MSBit MISO MISO MOSI MOSI SCK SS LSBit 8-BIT SHIFT REGISTER SCK +5V SS Not used if SS is managed by software 90/215 ST72F521, ST72521B SERIAL PERIPHERAL INTERFACE (Cont'd) 10.5.3.2 Slave Select Management As an alternative to using the SS pin to control the Slave Select signal, the application can choose to manage the Slave Select signal by software. This is configured by the SSM bit in the SPICSR register (see Figure 56) In software management, the external SS pin is free for other application uses and the internal SS signal level is driven by writing to the SSI bit in the SPICSR register. In Master mode: - SS internal must be held high continuously In Slave Mode: There are two cases depending on the data/clock timing relationship (see Figure 55): If CPHA=1 (data latched on 2nd clock edge): - SS internal must be held low during the entire transmission. This implies that in single slave applications the SS pin either can be tied to VSS, or made free for standard I/O by managing the SS function by software (SSM= 1 and SSI=0 in the in the SPICSR register) If CPHA=0 (data latched on 1st clock edge): - SS internal must be held low during byte transmission and pulled high between each byte to allow the slave to write to the shift register. If SS is not pulled high, a Write Collision error will occur when the slave writes to the shift register (see Section 10.5.5.3). Figure 55. Generic SS Timing Diagram MOSI/MISO Byte 1 Byte 2 Byte 3 Master SS Slave SS (if CPHA=0) Slave SS (if CPHA=1) Figure 56. Hardware/Software Slave Select Management SSM bit SSI bit 1 SS external pin 0 SS internal 91/215 ST72F521, ST72521B SERIAL PERIPHERAL INTERFACE (Cont'd) 10.5.3.3 Master Mode Operation In master mode, the serial clock is output on the SCK pin. The clock frequency, polarity and phase are configured by software (refer to the description of the SPICSR register). Note: The idle state of SCK must correspond to the polarity selected in the SPICSR register (by pulling up SCK if CPOL=1 or pulling down SCK if CPOL=0). To operate the SPI in master mode, perform the following steps in order (if the SPICSR register is not written first, the SPICR register setting (MSTR bit) may be not taken into account): 1. Write to the SPICR register: - Select the clock frequency by configuring the SPR[2:0] bits. - Select the clock polarity and clock phase by configuring the CPOL and CPHA bits. Figure 57 shows the four possible configurations. Note: The slave must have the same CPOL and CPHA settings as the master. 2. Write to the SPICSR register: - Either set the SSM bit and set the SSI bit or clear the SSM bit and tie the SS pin high for the complete byte transmit sequence. 3. Write to the SPICR register: - Set the MSTR and SPE bits Note: MSTR and SPE bits remain set only if SS is high). The transmit sequence begins when software writes a byte in the SPIDR register. 10.5.3.4 Master Mode Transmit Sequence When software writes to the SPIDR register, the data byte is loaded into the 8-bit shift register and then shifted out serially to the MOSI pin most significant bit first. When data transfer is complete: - The SPIF bit is set by hardware - An interrupt request is generated if the SPIE bit is set and the interrupt mask in the CCR register is cleared. Clearing the SPIF bit is performed by the following software sequence: 1. An access to the SPICSR register while the SPIF bit is set 2. A read to the SPIDR register. 92/215 Note: While the SPIF bit is set, all writes to the SPIDR register are inhibited until the SPICSR register is read. 10.5.3.5 Slave Mode Operation In slave mode, the serial clock is received on the SCK pin from the master device. To operate the SPI in slave mode: 1. Write to the SPICSR register to perform the following actions: - Select the clock polarity and clock phase by configuring the CPOL and CPHA bits (see Figure 57). Note: The slave must have the same CPOL and CPHA settings as the master. - Manage the SS pin as described in Section 10.5.3.2 and Figure 55. If CPHA=1 SS must be held low continuously. If CPHA=0 SS must be held low during byte transmission and pulled up between each byte to let the slave write in the shift register. 2. Write to the SPICR register to clear the MSTR bit and set the SPE bit to enable the SPI I/O functions. 10.5.3.6 Slave Mode Transmit Sequence When software writes to the SPIDR register, the data byte is loaded into the 8-bit shift register and then shifted out serially to the MISO pin most significant bit first. The transmit sequence begins when the slave device receives the clock signal and the most significant bit of the data on its MOSI pin. When data transfer is complete: - The SPIF bit is set by hardware - An interrupt request is generated if SPIE bit is set and interrupt mask in the CCR register is cleared. Clearing the SPIF bit is performed by the following software sequence: 1. An access to the SPICSR register while the SPIF bit is set. 2. A write or a read to the SPIDR register. Notes: While the SPIF bit is set, all writes to the SPIDR register are inhibited until the SPICSR register is read. The SPIF bit can be cleared during a second transmission; however, it must be cleared before the second SPIF bit in order to prevent an Overrun condition (see Section 10.5.5.2). ST72F521, ST72521B SERIAL PERIPHERAL INTERFACE (Cont'd) 10.5.4 Clock Phase and Clock Polarity Four possible timing relationships may be chosen by software, using the CPOL and CPHA bits (See Figure 57). Note: The idle state of SCK must correspond to the polarity selected in the SPICSR register (by pulling up SCK if CPOL=1 or pulling down SCK if CPOL=0). The combination of the CPOL clock polarity and CPHA (clock phase) bits selects the data capture clock edge Figure 57, shows an SPI transfer with the four combinations of the CPHA and CPOL bits. The diagram may be interpreted as a master or slave timing diagram where the SCK pin, the MISO pin, the MOSI pin are directly connected between the master and the slave device. Note: If CPOL is changed at the communication byte boundaries, the SPI must be disabled by resetting the SPE bit. Figure 57. Data Clock Timing Diagram CPHA =1 SCK (CPOL = 1) SCK (CPOL = 0) MISO (from master) MOSI (from slave) MSBit Bit 6 Bit 5 Bit 4 Bit3 Bit 2 Bit 1 LSBit MSBit Bit 6 Bit 5 Bit 4 Bit3 Bit 2 Bit 1 LSBit SS (to slave) CAPTURE STROBE CPHA =0 SCK (CPOL = 1) SCK (CPOL = 0) MISO (from master) MOSI (from slave) MSBit MSBit Bit 6 Bit 5 Bit 4 Bit3 Bit 2 Bit 1 LSBit Bit 6 Bit 5 Bit 4 Bit3 Bit 2 Bit 1 LSBit SS (to slave) CAPTURE STROBE Note: This figure should not be used as a replacement for parametric information. Refer to the Electrical Characteristics chapter. 93/215 ST72F521, ST72521B SERIAL PERIPHERAL INTERFACE (Cont'd) 10.5.5 Error Flags 10.5.5.1 Master Mode Fault (MODF) Master mode fault occurs when the master device has its SS pin pulled low. When a Master mode fault occurs: - The MODF bit is set and an SPI interrupt request is generated if the SPIE bit is set. - The SPE bit is reset. This blocks all output from the device and disables the SPI peripheral. - The MSTR bit is reset, thus forcing the device into slave mode. Clearing the MODF bit is done through a software sequence: 1. A read access to the SPICSR register while the MODF bit is set. 2. A write to the SPICR register. Notes: To avoid any conflicts in an application with multiple slaves, the SS pin must be pulled high during the MODF bit clearing sequence. The SPE and MSTR bits may be restored to their original state during or after this clearing sequence. Hardware does not allow the user to set the SPE and MSTR bits while the MODF bit is set except in the MODF bit clearing sequence. 10.5.5.2 Overrun Condition (OVR) An overrun condition occurs, when the master device has sent a data byte and the slave device has not cleared the SPIF bit issued from the previously transmitted byte. When an Overrun occurs: - The OVR bit is set and an interrupt request is generated if the SPIE bit is set. In this case, the receiver buffer contains the byte sent after the SPIF bit was last cleared. A read to the SPIDR register returns this byte. All other bytes are lost. The OVR bit is cleared by reading the SPICSR register. 10.5.5.3 Write Collision Error (WCOL) A write collision occurs when the software tries to write to the SPIDR register while a data transfer is taking place with an external device. When this happens, the transfer continues uninterrupted; and the software write will be unsuccessful. Write collisions can occur both in master and slave mode. See also Section 10.5.3.2 Slave Select Management. Note: a "read collision" will never occur since the received data byte is placed in a buffer in which access is always synchronous with the MCU operation. The WCOL bit in the SPICSR register is set if a write collision occurs. No SPI interrupt is generated when the WCOL bit is set (the WCOL bit is a status flag only). Clearing the WCOL bit is done through a software sequence (see Figure 58). Figure 58. Clearing the WCOL bit (Write Collision Flag) Software Sequence Clearing sequence after SPIF = 1 (end of a data byte transfer) 1st Step Read SPICSR RESULT 2nd Step Read SPIDR SPIF =0 WCOL=0 Clearing sequence before SPIF = 1 (during a data byte transfer) 1st Step Read SPICSR RESULT 2nd Step 94/215 Read SPIDR WCOL=0 Note: Writing to the SPIDR register instead of reading it does not reset the WCOL bit ST72F521, ST72521B SERIAL PERIPHERAL INTERFACE (Cont'd) 10.5.5.4 Single Master Systems A typical single master system may be configured, using an MCU as the master and four MCUs as slaves (see Figure 59). The master device selects the individual slave devices by using four pins of a parallel port to control the four SS pins of the slave devices. The SS pins are pulled high during reset since the master device ports will be forced to be inputs at that time, thus disabling the slave devices. Note: To prevent a bus conflict on the MISO line the master allows only one active slave device during a transmission. For more security, the slave device may respond to the master with the received data byte. Then the master will receive the previous byte back from the slave device if all MISO and MOSI pins are connected and the slave has not written to its SPIDR register. Other transmission security methods can use ports for handshake lines or data bytes with command fields. Figure 59. Single Master / Multiple Slave Configuration SS SCK SS SS SCK Slave MCU Slave MCU MOSI MISO MOSI MISO SS SCK Slave MCU SCK Slave MCU MOSI MISO MOSI MISO SCK Master MCU 5V Ports MOSI MISO SS 95/215 ST72F521, ST72521B SERIAL PERIPHERAL INTERFACE (Cont'd) 10.5.6 Low Power Modes Mode WAIT HALT Description No effect on SPI. SPI interrupt events cause the device to exit from WAIT mode. SPI registers are frozen. In HALT mode, the SPI is inactive. SPI operation resumes when the MCU is woken up by an interrupt with "exit from HALT mode" capability. The data received is subsequently read from the SPIDR register when the software is running (interrupt vector fetching). If several data are received before the wakeup event, then an overrun error is generated. This error can be detected after the fetch of the interrupt routine that woke up the device. Note: When waking up from Halt mode, if the SPI remains in Slave mode, it is recommended to perform an extra communications cycle to bring the SPI from Halt mode state to normal state. If the SPI exits from Slave mode, it returns to normal state immediately. Caution: The SPI can wake up the ST7 from Halt mode only if the Slave Select signal (external SS pin or the SSI bit in the SPICSR register) is low when the ST7 enters Halt mode. So if Slave selection is configured as external (see Section 10.5.3.2), make sure the master drives a low level on the SS pin when the slave enters Halt mode. 10.5.7 Interrupts Interrupt Event 10.5.6.1 Using the SPI to wakeup the MCU from Halt mode In slave configuration, the SPI is able to wakeup the ST7 device from HALT mode through a SPIF interrupt. The data received is subsequently read from the SPIDR register when the software is running (interrupt vector fetch). If multiple data transfers have been performed before software clears the SPIF bit, then the OVR bit is set by hardware. 96/215 SPI End of Transfer Event Master Mode Fault Event Overrun Error Event Flag Enable Control Bit SPIF MODF OVR SPIE Exit from Wait Exit from Halt Yes Yes Yes No Yes No Note: The SPI interrupt events are connected to the same interrupt vector (see Interrupts chapter). They generate an interrupt if the corresponding Enable Control Bit is set and the interrupt mask in ST72F521, ST72521B SERIAL PERIPHERAL INTERFACE (Cont'd) 10.5.8 Register Description CONTROL REGISTER (SPICR) Read/Write Reset Value: 0000 xxxx (0xh) 7 SPIE 0 SPE SPR2 MSTR CPOL CPHA SPR1 SPR0 Bit 7 = SPIE Serial Peripheral Interrupt Enable. This bit is set and cleared by software. 0: Interrupt is inhibited 1: An SPI interrupt is generated whenever SPIF=1, MODF=1 or OVR=1 in the SPICSR register Bit 6 = SPE Serial Peripheral Output Enable. This bit is set and cleared by software. It is also cleared by hardware when, in master mode, SS=0 (see Section 10.5.5.1 Master Mode Fault (MODF)). The SPE bit is cleared by reset, so the SPI peripheral is not initially connected to the external pins. 0: I/O pins free for general purpose I/O 1: SPI I/O pin alternate functions enabled Bit 5 = SPR2 Divider Enable. This bit is set and cleared by software and is cleared by reset. It is used with the SPR[1:0] bits to set the baud rate. Refer to Table 18 SPI Master mode SCK Frequency. 0: Divider by 2 enabled 1: Divider by 2 disabled Note: This bit has no effect in slave mode. Bit 4 = MSTR Master Mode. This bit is set and cleared by software. It is also cleared by hardware when, in master mode, SS=0 (see Section 10.5.5.1 Master Mode Fault (MODF)). 0: Slave mode 1: Master mode. The function of the SCK pin changes from an input to an output and the functions of the MISO and MOSI pins are reversed. Bit 3 = CPOL Clock Polarity. This bit is set and cleared by software. This bit determines the idle state of the serial Clock. The CPOL bit affects both the master and slave modes. 0: SCK pin has a low level idle state 1: SCK pin has a high level idle state Note: If CPOL is changed at the communication byte boundaries, the SPI must be disabled by resetting the SPE bit. Bit 2 = CPHA Clock Phase. This bit is set and cleared by software. 0: The first clock transition is the first data capture edge. 1: The second clock transition is the first capture edge. Note: The slave must have the same CPOL and CPHA settings as the master. Bits 1:0 = SPR[1:0] Serial Clock Frequency. These bits are set and cleared by software. Used with the SPR2 bit, they select the baud rate of the SPI serial clock SCK output by the SPI in master mode. Note: These 2 bits have no effect in slave mode. Table 18. SPI Master mode SCK Frequency Serial Clock SPR2 SPR1 SPR0 fCPU/4 1 0 0 fCPU/8 0 0 0 fCPU/16 0 0 1 fCPU/32 1 1 0 fCPU/64 0 1 0 fCPU/128 0 1 1 97/215 ST72F521, ST72521B SERIAL PERIPHERAL INTERFACE (Cont'd) CONTROL/STATUS REGISTER (SPICSR) Read/Write (some bits Read Only) Reset Value: 0000 0000 (00h) 7 SPIF Bit 3 = Reserved, must be kept cleared. 0 WCOL OVR MODF - SOD SSM SSI Bit 7 = SPIF Serial Peripheral Data Transfer Flag (Read only). This bit is set by hardware when a transfer has been completed. An interrupt is generated if SPIE=1 in the SPICR register. It is cleared by a software sequence (an access to the SPICSR register followed by a write or a read to the SPIDR register). 0: Data transfer is in progress or the flag has been cleared. 1: Data transfer between the device and an external device has been completed. Note: While the SPIF bit is set, all writes to the SPIDR register are inhibited until the SPICSR register is read. Bit 6 = WCOL Write Collision status (Read only). This bit is set by hardware when a write to the SPIDR register is done during a transmit sequence. It is cleared by a software sequence (see Figure 58). 0: No write collision occurred 1: A write collision has been detected Bit 2 = SOD SPI Output Disable. This bit is set and cleared by software. When set, it disables the alternate function of the SPI output (MOSI in master mode / MISO in slave mode) 0: SPI output enabled (if SPE=1) 1: SPI output disabled Bit 1 = SSM SS Management. This bit is set and cleared by software. When set, it disables the alternate function of the SPI SS pin and uses the SSI bit value instead. See Section 10.5.3.2 Slave Select Management. 0: Hardware management (SS managed by external pin) 1: Software management (internal SS signal controlled by SSI bit. External SS pin free for general-purpose I/O) Bit 0 = SSI SS Internal Mode. This bit is set and cleared by software. It acts as a `chip select' by controlling the level of the SS slave select signal when the SSM bit is set. 0 : Slave selected 1 : Slave deselected DATA I/O REGISTER (SPIDR) Read/Write Reset Value: Undefined 7 Bit 5 = OVR SPI Overrun error (Read only). This bit is set by hardware when the byte currently being received in the shift register is ready to be transferred into the SPIDR register while SPIF = 1 (See Section 10.5.5.2). An interrupt is generated if SPIE = 1 in SPICR register. The OVR bit is cleared by software reading the SPICSR register. 0: No overrun error 1: Overrun error detected Bit 4 = MODF Mode Fault flag (Read only). This bit is set by hardware when the SS pin is pulled low in master mode (see Section 10.5.5.1 Master Mode Fault (MODF)). An SPI interrupt can be generated if SPIE=1 in the SPICSR register. This bit is cleared by a software sequence (An access to the SPICR register while MODF=1 followed by a write to the SPICR register). 0: No master mode fault detected 1: A fault in master mode has been detected 98/215 D7 0 D6 D5 D4 D3 D2 D1 D0 The SPIDR register is used to transmit and receive data on the serial bus. In a master device, a write to this register will initiate transmission/reception of another byte. Notes: During the last clock cycle the SPIF bit is set, a copy of the received data byte in the shift register is moved to a buffer. When the user reads the serial peripheral data I/O register, the buffer is actually being read. While the SPIF bit is set, all writes to the SPIDR register are inhibited until the SPICSR register is read. Warning: A write to the SPIDR register places data directly into the shift register for transmission. A read to the SPIDR register returns the value located in the buffer and not the content of the shift register (see Figure 53). ST72F521, ST72521B SERIAL PERIPHERAL INTERFACE (Cont'd) Table 19. SPI Register Map and Reset Values Address (Hex.) 0021h 0022h 0023h Register Label 7 6 5 4 3 2 1 0 SPIDR Reset Value SPICR Reset Value SPICSR Reset Value MSB x SPIE 0 SPIF 0 x SPE 0 WCOL 0 x SPR2 0 OR 0 x MSTR 0 MODF 0 x CPOL x x CPHA x SOD 0 x SPR1 x SSM 0 LSB x SPR0 x SSI 0 0 99/215 ST72F521, ST72521B 10.6 SERIAL COMMUNICATIONS INTERFACE (SCI) 10.6.1 Introduction The Serial Communications Interface (SCI) offers a flexible means of full-duplex data exchange with external equipment requiring an industry standard NRZ asynchronous serial data format. The SCI offers a very wide range of baud rates using two baud rate generator systems. 10.6.2 Main Features Full duplex, asynchronous communications NRZ standard format (Mark/Space) Dual baud rate generator systems Independently programmable transmit and receive baud rates up to 500K baud. Programmable data word length (8 or 9 bits) Receive buffer full, Transmit buffer empty and End of Transmission flags Two receiver wake-up modes: - Address bit (MSB) - Idle line Muting function for multiprocessor configurations Separate enable bits for Transmitter and Receiver Four error detection flags: - Overrun error - Noise error - Frame error - Parity error Five interrupt sources with flags: - Transmit data register empty - Transmission complete - Receive data register full - Idle line received - Overrun error detected Parity control: - Transmits parity bit - Checks parity of received data byte Reduced power consumption mode 100/215 10.6.3 General Description The interface is externally connected to another device by two pins (see Figure 61): - TDO: Transmit Data Output. When the transmitter and the receiver are disabled, the output pin returns to its I/O port configuration. When the transmitter and/or the receiver are enabled and nothing is to be transmitted, the TDO pin is at high level. - RDI: Receive Data Input is the serial data input. Oversampling techniques are used for data recovery by discriminating between valid incoming data and noise. Through these pins, serial data is transmitted and received as frames comprising: - An Idle Line prior to transmission or reception - A start bit - A data word (8 or 9 bits) least significant bit first - A Stop bit indicating that the frame is complete. This interface uses two types of baud rate generator: - A conventional type for commonly-used baud rates, - An extended type with a prescaler offering a very wide range of baud rates even with non-standard oscillator frequencies. ST72F521, ST72521B SERIAL COMMUNICATIONS INTERFACE (Cont'd) Figure 60. SCI Block Diagram Write Read (DATA REGISTER) DR Received Data Register (RDR) Transmit Data Register (TDR) TDO Received Shift Register Transmit Shift Register RDI CR1 R8 TRANSMIT WAKE UP CONTROL UNIT T8 SCID M WAKE PCE PS PIE RECEIVER CLOCK RECEIVER CONTROL CR2 SR TIE TCIE RIE ILIE TE RE RWU SBK TDRE TC RDRF IDLE OR NF FE PE SCI INTERRUPT CONTROL TRANSMITTER CLOCK TRANSMITTER RATE fCPU CONTROL /16 /PR BRR SCP1 SCP0 SCT2 SCT1 SCT0 SCR2 SCR1SCR0 RECEIVER RATE CONTROL CONVENTIONAL BAUD RATE GENERATOR 101/215 ST72F521, ST72521B SERIAL COMMUNICATIONS INTERFACE (Cont'd) 10.6.4 Functional Description The block diagram of the Serial Control Interface, is shown in Figure 60. It contains 6 dedicated registers: - Two control registers (SCICR1 & SCICR2) - A status register (SCISR) - A baud rate register (SCIBRR) - An extended prescaler receiver register (SCIERPR) - An extended prescaler transmitter register (SCIETPR) Refer to the register descriptions in Section 10.6.7for the definitions of each bit. 10.6.4.1 Serial Data Format Word length may be selected as being either 8 or 9 bits by programming the M bit in the SCICR1 register (see Figure 60). The TDO pin is in low state during the start bit. The TDO pin is in high state during the stop bit. An Idle character is interpreted as an entire frame of "1"s followed by the start bit of the next frame which contains data. A Break character is interpreted on receiving "0"s for some multiple of the frame period. At the end of the last break frame the transmitter inserts an extra "1" bit to acknowledge the start bit. Transmission and reception are driven by their own baud rate generator. Figure 61. Word Length Programming 9-bit Word length (M bit is set) Possible Parity Bit Data Frame Start Bit Bit0 Bit2 Bit1 Bit3 Bit4 Bit5 Bit6 Start Bit Break Frame Extra '1' Possible Parity Bit Data Frame 102/215 Bit0 Bit8 Next Stop Start Bit Bit Idle Frame 8-bit Word length (M bit is reset) Start Bit Bit7 Next Data Frame Bit1 Bit2 Bit3 Bit4 Bit5 Bit6 Bit7 Start Bit Next Data Frame Stop Bit Next Start Bit Idle Frame Start Bit Break Frame Extra Start Bit '1' ST72F521, ST72521B SERIAL COMMUNICATIONS INTERFACE (Cont'd) 10.6.4.2 Transmitter The transmitter can send data words of either 8 or 9 bits depending on the M bit status. When the M bit is set, word length is 9 bits and the 9th bit (the MSB) has to be stored in the T8 bit in the SCICR1 register. Character Transmission During an SCI transmission, data shifts out least significant bit first on the TDO pin. In this mode, the SCIDR register consists of a buffer (TDR) between the internal bus and the transmit shift register (see Figure 60). Procedure - Select the M bit to define the word length. - Select the desired baud rate using the SCIBRR and the SCIETPR registers. - Set the TE bit to assign the TDO pin to the alternate function and to send a idle frame as first transmission. - Access the SCISR register and write the data to send in the SCIDR register (this sequence clears the TDRE bit). Repeat this sequence for each data to be transmitted. Clearing the TDRE bit is always performed by the following software sequence: 1. An access to the SCISR register 2. A write to the SCIDR register The TDRE bit is set by hardware and it indicates: - The TDR register is empty. - The data transfer is beginning. - The next data can be written in the SCIDR register without overwriting the previous data. This flag generates an interrupt if the TIE bit is set and the I bit is cleared in the CCR register. When a transmission is taking place, a write instruction to the SCIDR register stores the data in the TDR register and which is copied in the shift register at the end of the current transmission. When no transmission is taking place, a write instruction to the SCIDR register places the data directly in the shift register, the data transmission starts, and the TDRE bit is immediately set. When a frame transmission is complete (after the stop bit or after the break frame) the TC bit is set and an interrupt is generated if the TCIE is set and the I bit is cleared in the CCR register. Clearing the TC bit is performed by the following software sequence: 1. An access to the SCISR register 2. A write to the SCIDR register Note: The TDRE and TC bits are cleared by the same software sequence. Break Characters Setting the SBK bit loads the shift register with a break character. The break frame length depends on the M bit (see Figure 61). As long as the SBK bit is set, the SCI send break frames to the TDO pin. After clearing this bit by software the SCI insert a logic 1 bit at the end of the last break frame to guarantee the recognition of the start bit of the next frame. Idle Characters Setting the TE bit drives the SCI to send an idle frame before the first data frame. Clearing and then setting the TE bit during a transmission sends an idle frame after the current word. Note: Resetting and setting the TE bit causes the data in the TDR register to be lost. Therefore the best time to toggle the TE bit is when the TDRE bit is set i.e. before writing the next byte in the SCIDR. 103/215 ST72F521, ST72521B SERIAL COMMUNICATIONS INTERFACE (Cont'd) 10.6.4.3 Receiver The SCI can receive data words of either 8 or 9 bits. When the M bit is set, word length is 9 bits and the MSB is stored in the R8 bit in the SCICR1 register. Character reception During a SCI reception, data shifts in least significant bit first through the RDI pin. In this mode, the SCIDR register consists or a buffer (RDR) between the internal bus and the received shift register (see Figure 60). Procedure - Select the M bit to define the word length. - Select the desired baud rate using the SCIBRR and the SCIERPR registers. - Set the RE bit, this enables the receiver which begins searching for a start bit. When a character is received: - The RDRF bit is set. It indicates that the content of the shift register is transferred to the RDR. - An interrupt is generated if the RIE bit is set and the I bit is cleared in the CCR register. - The error flags can be set if a frame error, noise or an overrun error has been detected during reception. Clearing the RDRF bit is performed by the following software sequence done by: 1. An access to the SCISR register 2. A read to the SCIDR register. The RDRF bit must be cleared before the end of the reception of the next character to avoid an overrun error. Break Character When a break character is received, the SPI handles it as a framing error. Idle Character When a idle frame is detected, there is the same procedure as a data received character plus an interrupt if the ILIE bit is set and the I bit is cleared in the CCR register. Overrun Error An overrun error occurs when a character is received when RDRF has not been reset. Data can not be transferred from the shift register to the 104/215 RDR register as long as the RDRF bit is not cleared. When a overrun error occurs: - The OR bit is set. - The RDR content will not be lost. - The shift register will be overwritten. - An interrupt is generated if the RIE bit is set and the I bit is cleared in the CCR register. The OR bit is reset by an access to the SCISR register followed by a SCIDR register read operation. Noise Error Oversampling techniques are used for data recovery by discriminating between valid incoming data and noise. Normal data bits are considered valid if three consecutive samples (8th, 9th, 10th) have the same bit value, otherwise the NF flag is set. In the case of start bit detection, the NF flag is set on the basis of an algorithm combining both valid edge detection and three samples (8th, 9th, 10th). Therefore, to prevent the NF flag getting set during start bit reception, there should be a valid edge detection as well as three valid samples. When noise is detected in a frame: - The NF flag is set at the rising edge of the RDRF bit. - Data is transferred from the Shift register to the SCIDR register. - No interrupt is generated. However this bit rises at the same time as the RDRF bit which itself generates an interrupt. The NF flag is reset by a SCISR register read operation followed by a SCIDR register read operation. During reception, if a false start bit is detected (e.g. 8th, 9th, 10th samples are 011,101,110), the frame is discarded and the receiving sequence is not started for this frame. There is no RDRF bit set for this frame and the NF flag is set internally (not accessible to the user). This NF flag is accessible along with the RDRF bit when a next valid frame is received. Note: If the application Start Bit is not long enough to match the above requirements, then the NF Flag may get set due to the short Start Bit. In this case, the NF flag may be ignored by the application software when the first valid byte is received. See also Section 10.6.4.10. ST72F521, ST72521B SERIAL COMMUNICATIONS INTERFACE (Cont'd) Figure 62. SCI Baud Rate and Extended Prescaler Block Diagram TRANSMITTER CLOCK EXTENDED PRESCALER TRANSMITTER RATE CONTROL SCIETPR EXTENDED TRANSMITTER PRESCALER REGISTER SCIERPR EXTENDED RECEIVER PRESCALER REGISTER RECEIVER CLOCK EXTENDED PRESCALER RECEIVER RATE CONTROL EXTENDED PRESCALER fCPU TRANSMITTER RATE CONTROL /16 /PR SCIBRR SCP1 SCP0 SCT2 SCT1 SCT0 SCR2 SCR1SCR0 RECEIVER RATE CONTROL CONVENTIONAL BAUD RATE GENERATOR 105/215 ST72F521, ST72521B SERIAL COMMUNICATIONS INTERFACE (Cont'd) Framing Error A framing error is detected when: - The stop bit is not recognized on reception at the expected time, following either a de-synchronization or excessive noise. - A break is received. When the framing error is detected: - the FE bit is set by hardware - Data is transferred from the Shift register to the SCIDR register. - No interrupt is generated. However this bit rises at the same time as the RDRF bit which itself generates an interrupt. The FE bit is reset by a SCISR register read operation followed by a SCIDR register read operation. 10.6.4.4 Conventional Baud Rate Generation The baud rate for the receiver and transmitter (Rx and Tx) are set independently and calculated as follows: Tx = fCPU (16*PR)*TR Rx = fCPU (16*PR)*RR with: PR = 1, 3, 4 or 13 (see SCP[1:0] bits) TR = 1, 2, 4, 8, 16, 32, 64,128 (see SCT[2:0] bits) RR = 1, 2, 4, 8, 16, 32, 64,128 (see SCR[2:0] bits) All these bits are in the SCIBRR register. Example: If fCPU is 8 MHz (normal mode) and if PR=13 and TR=RR=1, the transmit and receive baud rates are 38400 baud. Note: the baud rate registers MUST NOT be changed while the transmitter or the receiver is enabled. 10.6.4.5 Extended Baud Rate Generation The extended prescaler option gives a very fine tuning on the baud rate, using a 255 value prescaler, whereas the conventional Baud Rate Generator retains industry standard software compatibility. The extended baud rate generator block diagram is described in the Figure 62. The output clock rate sent to the transmitter or to the receiver will be the output from the 16 divider divided by a factor ranging from 1 to 255 set in the SCIERPR or the SCIETPR register. 106/215 Note: the extended prescaler is activated by setting the SCIETPR or SCIERPR register to a value other than zero. The baud rates are calculated as follows: fCPU fCPU Rx = Tx = 16*ERPR*(PR*RR) 16*ETPR*(PR*TR) with: ETPR = 1,..,255 (see SCIETPR register) ERPR = 1,.. 255 (see SCIERPR register) 10.6.4.6 Receiver Muting and Wake-up Feature In multiprocessor configurations it is often desirable that only the intended message recipient should actively receive the full message contents, thus reducing redundant SCI service overhead for all non addressed receivers. The non addressed devices may be placed in sleep mode by means of the muting function. Setting the RWU bit by software puts the SCI in sleep mode: All the reception status bits can not be set. All the receive interrupts are inhibited. A muted receiver may be awakened by one of the following two ways: - by Idle Line detection if the WAKE bit is reset, - by Address Mark detection if the WAKE bit is set. Receiver wakes-up by Idle Line detection when the Receive line has recognised an Idle Frame. Then the RWU bit is reset by hardware but the IDLE bit is not set. Receiver wakes-up by Address Mark detection when it received a "1" as the most significant bit of a word, thus indicating that the message is an address. The reception of this particular word wakes up the receiver, resets the RWU bit and sets the RDRF bit, which allows the receiver to receive this word normally and to use it as an address word. Caution: In Mute mode, do not write to the SCICR2 register. If the SCI is in Mute mode during the read operation (RWU=1) and a address mark wake up event occurs (RWU is reset) before the write operation, the RWU bit will be set again by this write operation. Consequently the address byte is lost and the SCI is not woken up from Mute mode. ST72F521, ST72521B SERIAL COMMUNICATIONS INTERFACE (Cont'd) 10.6.4.7 Parity Control Parity control (generation of parity bit in transmission and parity checking in reception) can be enabled by setting the PCE bit in the SCICR1 register. Depending on the frame length defined by the M bit, the possible SCI frame formats are as listed in Table 20. Table 20. Frame Formats M bit 0 0 1 1 PCE bit 0 1 0 1 SCI frame | SB | 8 bit data | STB | | SB | 7-bit data | PB | STB | | SB | 9-bit data | STB | | SB | 8-bit data PB | STB | Legend: SB = Start Bit, STB = Stop Bit, PB = Parity Bit Note: In case of wake up by an address mark, the MSB bit of the data is taken into account and not the parity bit Even parity: the parity bit is calculated to obtain an even number of "1s" inside the frame made of the 7 or 8 LSB bits (depending on whether M is equal to 0 or 1) and the parity bit. Ex: data=00110101; 4 bits set => parity bit will be 0 if even parity is selected (PS bit = 0). Odd parity: the parity bit is calculated to obtain an odd number of "1s" inside the frame made of the 7 or 8 LSB bits (depending on whether M is equal to 0 or 1) and the parity bit. Ex: data=00110101; 4 bits set => parity bit will be 1 if odd parity is selected (PS bit = 1). Transmission mode: If the PCE bit is set then the MSB bit of the data written in the data register is not transmitted but is changed by the parity bit. Reception mode: If the PCE bit is set then the interface checks if the received data byte has an even number of "1s" if even parity is selected (PS=0) or an odd number of "1s" if odd parity is selected (PS=1). If the parity check fails, the PE flag is set in the SCISR register and an interrupt is generated if PIE is set in the SCICR1 register. 10.6.4.8 SCI Clock Tolerance During reception, each bit is sampled 16 times. The majority of the 8th, 9th and 10th samples is considered as the bit value. For a valid bit detection, all the three samples should have the same value otherwise the noise flag (NF) is set. For example: if the 8th, 9th and 10th samples are 0, 1 and 1 respectively, then the bit value will be "1", but the Noise Flag bit is be set because the three samples values are not the same. Consequently, the bit length must be long enough so that the 8th, 9th and 10th samples have the desired bit value. This means the clock frequency should not vary more than 6/16 (37.5%) within one bit. The sampling clock is resynchronized at each start bit, so that when receiving 10 bits (one start bit, 1 data byte, 1 stop bit), the clock deviation must not exceed 3.75%. Note: The internal sampling clock of the microcontroller samples the pin value on every falling edge. Therefore, the internal sampling clock and the time the application expects the sampling to take place may be out of sync. For example: If the baud rate is 15.625 kbaud (bit length is 64s), then the 8th, 9th and 10th samples will be at 28s, 32s & 36s respectively (the first sample starting ideally at 0s). But if the falling edge of the internal clock occurs just before the pin value changes, the samples would then be out of sync by ~4us. This means the entire bit length must be at least 40s (36s for the 10th sample + 4s for synchronization with the internal sampling clock). 107/215 ST72F521, ST72521B SERIAL COMMUNICATIONS INTERFACE (Cont'd) 10.6.4.9 Clock Deviation Causes The causes which contribute to the total deviation are: - DTRA: Deviation due to transmitter error (Local oscillator error of the transmitter or the transmitter is transmitting at a different baud rate). - DQUANT: Error due to the baud rate quantisation of the receiver. - DREC: Deviation of the local oscillator of the receiver: This deviation can occur during the reception of one complete SCI message assuming that the deviation has been compensated at the beginning of the message. - DTCL: Deviation due to the transmission line (generally due to the transceivers) All the deviations of the system should be added and compared to the SCI clock tolerance: DTRA + DQUANT + DREC + DTCL < 3.75% 10.6.4.10 Noise Error Causes See also description of Noise error in Section 10.6.4.3. Start bit The noise flag (NF) is set during start bit reception if one of the following conditions occurs: 1. A valid falling edge is not detected. A falling edge is considered to be valid if the 3 consecutive samples before the falling edge occurs are detected as '1' and, after the falling edge occurs, during the sampling of the 16 samples, if one of the samples numbered 3, 5 or 7 is detected as a "1". 2. During sampling of the 16 samples, if one of the samples numbered 8, 9 or 10 is detected as a "1". Therefore, a valid Start Bit must satisfy both the above conditions to prevent the Noise Flag getting set. Data Bits The noise flag (NF) is set during normal data bit reception if the following condition occurs: - During the sampling of 16 samples, if all three samples numbered 8, 9 and10 are not the same. The majority of the 8th, 9th and 10th samples is considered as the bit value. Therefore, a valid Data Bit must have samples 8, 9 and 10 at the same value to prevent the Noise Flag getting set. Figure 63. Bit Sampling in Reception Mode RDI LINE sampled values Sample clock 1 2 3 4 5 6 7 8 9 10 11 12 13 6/16 7/16 7/16 One bit time 108/215 14 15 16 ST72F521, ST72521B SERIAL COMMUNICATIONS INTERFACE (Cont'd) 10.6.5 Low Power Modes Mode Description No effect on SCI. WAIT SCI interrupts cause the device to exit from Wait mode. SCI registers are frozen. HALT In Halt mode, the SCI stops transmitting/receiving until Halt mode is exited. 10.6.6 Interrupts The SCI interrupt events are connected to the same interrupt vector. These events generate an interrupt if the corresponding Enable Control Bit is set and the inter- Interrupt Event Enable Exit Event Control from Flag Bit Wait Transmit Data Register TDRE Empty Transmission ComTC plete Received Data Ready RDRF to be Read Overrun Error Detected OR Idle Line Detected IDLE Parity Error PE Exit from Halt TIE Yes No TCIE Yes No Yes No Yes Yes Yes No No No RIE ILIE PIE rupt mask in the CC register is reset (RIM instruction). 109/215 ST72F521, ST72521B SERIAL COMMUNICATIONS INTERFACE (Cont'd) 10.6.7 Register Description Note: The IDLE bit will not be set again until the RDRF bit has been set itself (i.e. a new idle line ocSTATUS REGISTER (SCISR) curs). Read Only Reset Value: 1100 0000 (C0h) Bit 3 = OR Overrun error. 7 0 This bit is set by hardware when the word currently being received in the shift register is ready to be TDRE TC RDRF IDLE OR NF FE PE transferred into the RDR register while RDRF=1. An interrupt is generated if RIE=1 in the SCICR2 register. It is cleared by a software sequence (an Bit 7 = TDRE Transmit data register empty. access to the SCISR register followed by a read to This bit is set by hardware when the content of the the SCIDR register). TDR register has been transferred into the shift 0: No Overrun error register. An interrupt is generated if the TIE bit=1 1: Overrun error is detected in the SCICR2 register. It is cleared by a software sequence (an access to the SCISR register folNote: When this bit is set RDR register content will lowed by a write to the SCIDR register). not be lost but the shift register will be overwritten. 0: Data is not transferred to the shift register 1: Data is transferred to the shift register Bit 2 = NF Noise flag. Note: Data will not be transferred to the shift regThis bit is set by hardware when noise is detected ister unless the TDRE bit is cleared. on a received frame. It is cleared by a software sequence (an access to the SCISR register followed by a read to the SCIDR register). Bit 6 = TC Transmission complete. 0: No noise is detected This bit is set by hardware when transmission of a 1: Noise is detected frame containing Data is complete. An interrupt is generated if TCIE=1 in the SCICR2 register. It is Note: This bit does not generate interrupt as it apcleared by a software sequence (an access to the pears at the same time as the RDRF bit which itSCISR register followed by a write to the SCIDR self generates an interrupt. register). 0: Transmission is not complete 1: Transmission is complete Bit 1 = FE Framing error. This bit is set by hardware when a de-synchronizaNote: TC is not set after the transmission of a Pretion, excessive noise or a break character is deamble or a Break. tected. It is cleared by a software sequence (an access to the SCISR register followed by a read to Bit 5 = RDRF Received data ready flag. the SCIDR register). This bit is set by hardware when the content of the 0: No Framing error is detected RDR register has been transferred to the SCIDR 1: Framing error or break character is detected register. An interrupt is generated if RIE=1 in the Note: This bit does not generate interrupt as it apSCICR2 register. It is cleared by a software sepears at the same time as the RDRF bit which itquence (an access to the SCISR register followed self generates an interrupt. If the word currently by a read to the SCIDR register). being transferred causes both frame error and 0: Data is not received overrun error, it will be transferred and only the OR 1: Received data is ready to be read bit will be set. Bit 4 = IDLE Idle line detect. This bit is set by hardware when a Idle Line is detected. An interrupt is generated if the ILIE=1 in the SCICR2 register. It is cleared by a software sequence (an access to the SCISR register followed by a read to the SCIDR register). 0: No Idle Line is detected 1: Idle Line is detected 110/215 Bit 0 = PE Parity error. This bit is set by hardware when a parity error occurs in receiver mode. It is cleared by a software sequence (a read to the status register followed by an access to the SCIDR data register). An interrupt is generated if PIE=1 in the SCICR1 register. 0: No parity error 1: Parity error ST72F521, ST72521B SERIAL COMMUNICATIONS INTERFACE (Cont'd) CONTROL REGISTER 1 (SCICR1) Read/Write Bit 3 = WAKE Wake-Up method. This bit determines the SCI Wake-Up method, it is Reset Value: x000 0000 (x0h) set or cleared by software. 0: Idle Line 7 0 1: Address Mark R8 T8 SCID M WAKE PCE PS PIE Bit 7 = R8 Receive data bit 8. This bit is used to store the 9th bit of the received word when M=1. Bit 6 = T8 Transmit data bit 8. This bit is used to store the 9th bit of the transmitted word when M=1. Bit 5 = SCID Disabled for low power consumption When this bit is set the SCI prescalers and outputs are stopped and the end of the current byte transfer in order to reduce power consumption.This bit is set and cleared by software. 0: SCI enabled 1: SCI prescaler and outputs disabled Bit 4 = M Word length. This bit determines the word length. It is set or cleared by software. 0: 1 Start bit, 8 Data bits, 1 Stop bit 1: 1 Start bit, 9 Data bits, 1 Stop bit Note: The M bit must not be modified during a data transfer (both transmission and reception). Bit 2 = PCE Parity control enable. This bit selects the hardware parity control (generation and detection). When the parity control is enabled, the computed parity is inserted at the MSB position (9th bit if M=1; 8th bit if M=0) and parity is checked on the received data. This bit is set and cleared by software. Once it is set, PCE is active after the current byte (in reception and in transmission). 0: Parity control disabled 1: Parity control enabled Bit 1 = PS Parity selection. This bit selects the odd or even parity when the parity generation/detection is enabled (PCE bit set). It is set and cleared by software. The parity will be selected after the current byte. 0: Even parity 1: Odd parity Bit 0 = PIE Parity interrupt enable. This bit enables the interrupt capability of the hardware parity control when a parity error is detected (PE bit set). It is set and cleared by software. 0: Parity error interrupt disabled 1: Parity error interrupt enabled. 111/215 ST72F521, ST72521B SERIAL COMMUNICATIONS INTERFACE (Cont'd) CONTROL REGISTER 2 (SCICR2) Notes: Read/Write - During transmission, a "0" pulse on the TE bit ("0" followed by "1") sends a preamble (idle line) Reset Value: 0000 0000 (00h) after the current word. 7 0 - When TE is set there is a 1 bit-time delay before the transmission starts. TIE TCIE RIE ILIE TE RE RWU SBK Caution: The TDO pin is free for general purpose I/O only when the TE and RE bits are both cleared (or if TE is never set). Bit 7 = TIE Transmitter interrupt enable. This bit is set and cleared by software. 0: Interrupt is inhibited Bit 2 = RE Receiver enable. 1: An SCI interrupt is generated whenever This bit enables the receiver. It is set and cleared TDRE=1 in the SCISR register by software. 0: Receiver is disabled Bit 6 = TCIE Transmission complete interrupt ena1: Receiver is enabled and begins searching for a ble start bit This bit is set and cleared by software. 0: Interrupt is inhibited Bit 1 = RWU Receiver wake-up. 1: An SCI interrupt is generated whenever TC=1 in This bit determines if the SCI is in mute mode or the SCISR register not. It is set and cleared by software and can be cleared by hardware when a wake-up sequence is Bit 5 = RIE Receiver interrupt enable. recognized. This bit is set and cleared by software. 0: Receiver in Active mode 0: Interrupt is inhibited 1: Receiver in Mute mode 1: An SCI interrupt is generated whenever OR=1 Note: Before selecting Mute mode (setting the or RDRF=1 in the SCISR register RWU bit), the SCI must receive some data first, otherwise it cannot function in Mute mode with Bit 4 = ILIE Idle line interrupt enable. wakeup by idle line detection. This bit is set and cleared by software. 0: Interrupt is inhibited Bit 0 = SBK Send break. 1: An SCI interrupt is generated whenever IDLE=1 This bit set is used to send break characters. It is in the SCISR register. set and cleared by software. Bit 3 = TE Transmitter enable. This bit enables the transmitter. It is set and cleared by software. 0: Transmitter is disabled 1: Transmitter is enabled 112/215 0: No break character is transmitted 1: Break characters are transmitted Note: If the SBK bit is set to "1" and then to "0", the transmitter will send a BREAK word at the end of the current word. ST72F521, ST72521B SERIAL COMMUNICATIONS INTERFACE (Cont'd) DATA REGISTER (SCIDR) Read/Write Reset Value: Undefined Contains the Received or Transmitted data character, depending on whether it is read from or written to. 7 0 DR7 DR6 DR5 DR4 DR3 DR2 DR1 DR0 The Data register performs a double function (read and write) since it is composed of two registers, one for transmission (TDR) and one for reception (RDR). The TDR register provides the parallel interface between the internal bus and the output shift register (see Figure 60). The RDR register provides the parallel interface between the input shift register and the internal bus (see Figure 60). BAUD RATE REGISTER (SCIBRR) Read/Write Reset Value: 0000 0000 (00h) 7 0 SCP1 SCP0 SCT2 SCT1 SCT0 SCR2 SCR1 SCR0 Bits 7:6= SCP[1:0] First SCI Prescaler These 2 prescaling bits allow several standard clock division ranges: PR Prescaling factor SCP1 SCP0 1 0 0 3 0 1 4 1 0 13 1 1 Bits 5:3 = SCT[2:0] SCI Transmitter rate divisor These 3 bits, in conjunction with the SCP1 & SCP0 bits define the total division applied to the bus clock to yield the transmit rate clock in conventional Baud Rate Generator mode. TR dividing factor SCT2 SCT1 SCT0 1 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 Bits 2:0 = SCR[2:0] SCI Receiver rate divisor. These 3 bits, in conjunction with the SCP[1:0] bits define the total division applied to the bus clock to yield the receive rate clock in conventional Baud Rate Generator mode. RR Dividing factor SCR2 SCR1 SCR0 1 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 1 113/215 ST72F521, ST72521B SERIAL COMMUNICATIONS INTERFACE (Cont'd) EXTENDED RECEIVE PRESCALER DIVISION REGISTER (SCIERPR) Read/Write Reset Value: 0000 0000 (00h) Allows setting of the Extended Prescaler rate division factor for the receive circuit. 7 0 EXTENDED TRANSMIT PRESCALER DIVISION REGISTER (SCIETPR) Read/Write Reset Value:0000 0000 (00h) Allows setting of the External Prescaler rate division factor for the transmit circuit. 7 ERPR ERPR ERPR ERPR ERPR ERPR ERPR ERPR 7 6 5 4 3 2 1 0 ETPR 7 Bits 7:0 = ERPR[7:0] 8-bit Extended Receive Prescaler Register. The extended Baud Rate Generator is activated when a value different from 00h is stored in this register. Therefore the clock frequency issued from the 16 divider (see Figure 62) is divided by the binary factor set in the SCIERPR register (in the range 1 to 255). The extended baud rate generator is not used after a reset. 0 ETPR 6 ETPR 5 ETPR 4 ETPR 3 ETPR 2 ETPR ETPR 1 0 Bits 7:0 = ETPR[7:0] 8-bit Extended Transmit Prescaler Register. The extended Baud Rate Generator is activated when a value different from 00h is stored in this register. Therefore the clock frequency issued from the 16 divider (see Figure 62) is divided by the binary factor set in the SCIETPR register (in the range 1 to 255). The extended baud rate generator is not used after a reset. Table 21. Baudrate Selection Conditions Symbol Parameter fCPU Accuracy vs. Standard ~0.16% fTx fRx Communication frequency 8MHz ~0.79% 114/215 Prescaler Conventional Mode TR (or RR)=128, PR=13 TR (or RR)= 32, PR=13 TR (or RR)= 16, PR=13 TR (or RR)= 8, PR=13 TR (or RR)= 4, PR=13 TR (or RR)= 16, PR= 3 TR (or RR)= 2, PR=13 TR (or RR)= 1, PR=13 Extended Mode ETPR (or ERPR) = 35, TR (or RR)= 1, PR=1 Standard Baud Rate 300 ~300.48 1200 ~1201.92 2400 ~2403.84 4800 ~4807.69 9600 ~9615.38 10400 ~10416.67 19200 ~19230.77 38400 ~38461.54 14400 ~14285.71 Unit Hz ST72F521, ST72521B SERIAL COMMUNICATION INTERFACE (Cont'd) Table 22. SCI Register Map and Reset Values Address (Hex.) 0050h 0051h 0052h 0053h 0054h 0055h 0057h Register Label 7 6 5 4 3 2 1 0 SCISR Reset Value SCIDR Reset Value SCIBRR Reset Value SCICR1 Reset Value SCICR2 Reset Value SCIERPR Reset Value SCIPETPR Reset Value TDRE 1 MSB x SCP1 0 R8 x TIE 0 MSB 0 MSB 0 TC 1 RDRF 0 IDLE 0 OR 0 NF 0 FE 0 x SCP0 0 T8 0 TCIE 0 x SCT2 0 SCID 0 RIE 0 x SCT1 0 M 0 ILIE 0 x SCT0 0 WAKE 0 TE 0 x SCR2 0 PCE 0 RE 0 x SCR1 0 PS 0 RWU 0 0 0 0 0 0 0 0 0 0 0 0 0 PE 0 LSB x SCR0 0 PIE 0 SBK 0 LSB 0 LSB 0 115/215 ST72F521, ST72521B 10.7 I2C BUS INTERFACE (I2C) 10.7.1 Introduction The I2C Bus Interface serves as an interface between the microcontroller and the serial I2C bus. It provides both multimaster and slave functions, and controls all I2C bus-specific sequencing, protocol, arbitration and timing. It supports fast I2C mode (400kHz). 10.7.2 Main Features 2 Parallel-bus/I C protocol converter Multi-master capability 7-bit/10-bit Addressing SMBus V1.1 Compliant Transmitter/Receiver flag End-of-byte transmission flag Transfer problem detection I2C Master Features: Clock generation 2 I C bus busy flag Arbitration Lost Flag End of byte transmission flag Transmitter/Receiver Flag Start bit detection flag Start and Stop generation I2C Slave Features: Stop bit detection 2 I C bus busy flag Detection of misplaced start or stop condition 2 Programmable I C Address detection Transfer problem detection End-of-byte transmission flag Transmitter/Receiver flag 10.7.3 General Description In addition to receiving and transmitting data, this interface converts it from serial to parallel format and vice versa, using either an interrupt or polled handshake. The interrupts are enabled or disabled by software. The interface is connected to the I2C bus by a data pin (SDAI) and by a clock pin (SCLI). It can be connected both with a standard I2C bus and a Fast I2C bus. This selection is made by software. Mode Selection The interface can operate in the four following modes: - Slave transmitter/receiver - Master transmitter/receiver By default, it operates in slave mode. The interface automatically switches from slave to master after it generates a START condition and from master to slave in case of arbitration loss or a STOP generation, allowing then Multi-Master capability. Communication Flow In Master mode, it initiates a data transfer and generates the clock signal. A serial data transfer always begins with a start condition and ends with a stop condition. Both start and stop conditions are generated in master mode by software. In Slave mode, the interface is capable of recognising its own address (7 or 10-bit), and the General Call address. The General Call address detection may be enabled or disabled by software. Data and addresses are transferred as 8-bit bytes, MSB first. The first byte(s) following the start condition contain the address (one in 7-bit mode, two in 10-bit mode). The address is always transmitted in Master mode. A 9th clock pulse follows the 8 clock cycles of a byte transfer, during which the receiver must send an acknowledge bit to the transmitter. Refer to Figure 64. Figure 64. I2C BUS Protocol SDA ACK MSB SCL 1 START CONDITION 116/215 2 8 9 STOP CONDITION VR02119B ST72F521, ST72521B I2C BUS INTERFACE (Cont'd) Acknowledge may be enabled and disabled by software. The I2C interface address and/or general call address can be selected by software. The speed of the I2C interface may be selected between Standard (up to 100KHz) and Fast I2C (up to 400KHz). SDA/SCL Line Control Transmitter mode: the interface holds the clock line low before transmission to wait for the microcontroller to write the byte in the Data Register. Receiver mode: the interface holds the clock line low after reception to wait for the microcontroller to read the byte in the Data Register. The SCL frequency (Fscl) is controlled by a programmable clock divider which depends on the I2C bus mode. When the I2C cell is enabled, the SDA and SCL ports must be configured as floating inputs. In this case, the value of the external pull-up resistor used depends on the application. When the I2C cell is disabled, the SDA and SCL ports revert to being standard I/O port pins. Figure 65. I2C Interface Block Diagram DATA REGISTER (DR) SDA or SDAI DATA CONTROL DATA SHIFT REGISTER COMPARATOR OWN ADDRESS REGISTER 1 (OAR1) OWN ADDRESS REGISTER 2 (OAR2) SCL or SCLI CLOCK CONTROL CLOCK CONTROL REGISTER (CCR) CONTROL REGISTER (CR) STATUS REGISTER 1 (SR1) CONTROL LOGIC STATUS REGISTER 2 (SR2) INTERRUPT 117/215 ST72F521, ST72521B I2C BUS INTERFACE (Cont'd) 10.7.4 Functional Description Refer to the CR, SR1 and SR2 registers in Section 10.7.7. for the bit definitions. By default the I2C interface operates in Slave mode (M/SL bit is cleared) except when it initiates a transmit or receive sequence. First the interface frequency must be configured using the FRi bits in the OAR2 register. 10.7.4.1 Slave Mode As soon as a start condition is detected, the address is received from the SDA line and sent to the shift register; then it is compared with the address of the interface or the General Call address (if selected by software). Note: In 10-bit addressing mode, the comparison includes the header sequence (11110xx0) and the two most significant bits of the address. Header matched (10-bit mode only): the interface generates an acknowledge pulse if the ACK bit is set. Address not matched: the interface ignores it and waits for another Start condition. Address matched: the interface generates in sequence: - Acknowledge pulse if the ACK bit is set. - EVF and ADSL bits are set with an interrupt if the ITE bit is set. Then the interface waits for a read of the SR1 register, holding the SCL line low (see Figure 66 Transfer sequencing EV1). Next, in 7-bit mode read the DR register to determine from the least significant bit (Data Direction Bit) if the slave must enter Receiver or Transmitter mode. In 10-bit mode, after receiving the address sequence the slave is always in receive mode. It will enter transmit mode on receiving a repeated Start condition followed by the header sequence with matching address bits and the least significant bit set (11110xx1). Slave Receiver Following the address reception and after SR1 register has been read, the slave receives bytes from the SDA line into the DR register via the internal shift register. After each byte the interface generates in sequence: - Acknowledge pulse if the ACK bit is set - EVF and BTF bits are set with an interrupt if the ITE bit is set. 118/215 Then the interface waits for a read of the SR1 register followed by a read of the DR register, holding the SCL line low (see Figure 66 Transfer sequencing EV2). Slave Transmitter Following the address reception and after SR1 register has been read, the slave sends bytes from the DR register to the SDA line via the internal shift register. The slave waits for a read of the SR1 register followed by a write in the DR register, holding the SCL line low (see Figure 66 Transfer sequencing EV3). When the acknowledge pulse is received: - The EVF and BTF bits are set by hardware with an interrupt if the ITE bit is set. Closing slave communication After the last data byte is transferred a Stop Condition is generated by the master. The interface detects this condition and sets: - EVF and STOPF bits with an interrupt if the ITE bit is set. Then the interface waits for a read of the SR2 register (see Figure 66 Transfer sequencing EV4). Error Cases - BERR: Detection of a Stop or a Start condition during a byte transfer. In this case, the EVF and the BERR bits are set with an interrupt if the ITE bit is set. If it is a Stop then the interface discards the data, released the lines and waits for another Start condition. If it is a Start then the interface discards the data and waits for the next slave address on the bus. - AF: Detection of a non-acknowledge bit. In this case, the EVF and AF bits are set with an interrupt if the ITE bit is set. The AF bit is cleared by reading the I2CSR2 register. However, if read before the completion of the transmission, the AF flag will be set again, thus possibly generating a new interrupt. Software must ensure either that the SCL line is back at 0 before reading the SR2 register, or be able to correctly handle a second interrupt during the 9th pulse of a transmitted byte. Note: In case of errors, SCL line is not held low; however, the SDA line can remain low if the last bits transmitted are all 0. While AF=1, the SCL line may be held low due to SB or BTF flags that are set at the same time. It is then necessary to release both lines by software. ST72F521, ST72521B I2C INTERFACE (Cont'd) How to release the SDA / SCL lines Set and subsequently clear the STOP bit while BTF is set. The SDA/SCL lines are released after the transfer of the current byte. SMBus Compatibility ST7 I2C is compatible with SMBus V1.1 protocol. It supports all SMBus adressing modes, SMBus bus protocols and CRC-8 packet error checking. Refer to AN1713: SMBus Slave Driver For ST7 I2C Peripheral. 10.7.4.2 Master Mode To switch from default Slave mode to Master mode a Start condition generation is needed. Start condition Setting the START bit while the BUSY bit is cleared causes the interface to switch to Master mode (M/SL bit set) and generates a Start condition. Once the Start condition is sent: - The EVF and SB bits are set by hardware with an interrupt if the ITE bit is set. Then the master waits for a read of the SR1 register followed by a write in the DR register with the Slave address, holding the SCL line low (see Figure 66 Transfer sequencing EV5). Slave address transmission Then the slave address is sent to the SDA line via the internal shift register. In 7-bit addressing mode, one address byte is sent. In 10-bit addressing mode, sending the first byte including the header sequence causes the following event: - The EVF bit is set by hardware with interrupt generation if the ITE bit is set. Then the master waits for a read of the SR1 register followed by a write in the DR register, holding the SCL line low (see Figure 66 Transfer sequencing EV9). Then the second address byte is sent by the interface. After completion of this transfer (and acknowledge from the slave if the ACK bit is set): - The EVF bit is set by hardware with interrupt generation if the ITE bit is set. Then the master waits for a read of the SR1 register followed by a write in the CR register (for example set PE bit), holding the SCL line low (see Figure 66 Transfer sequencing EV6). Next the master must enter Receiver or Transmitter mode. Note: In 10-bit addressing mode, to switch the master to Receiver mode, software must generate a repeated Start condition and resend the header sequence with the least significant bit set (11110xx1). Master Receiver Following the address transmission and after SR1 and CR registers have been accessed, the master receives bytes from the SDA line into the DR register via the internal shift register. After each byte the interface generates in sequence: - Acknowledge pulse if the ACK bit is set - EVF and BTF bits are set by hardware with an interrupt if the ITE bit is set. Then the interface waits for a read of the SR1 register followed by a read of the DR register, holding the SCL line low (see Figure 66 Transfer sequencing EV7). To close the communication: before reading the last byte from the DR register, set the STOP bit to generate the Stop condition. The interface goes automatically back to slave mode (M/SL bit cleared). Note: In order to generate the non-acknowledge pulse after the last received data byte, the ACK bit must be cleared just before reading the second last data byte. 119/215 ST72F521, ST72521B I2C BUS INTERFACE (Cont'd) Master Transmitter Following the address transmission and after SR1 register has been read, the master sends bytes from the DR register to the SDA line via the internal shift register. The master waits for a read of the SR1 register followed by a write in the DR register, holding the SCL line low (see Figure 66 Transfer sequencing EV8). When the acknowledge bit is received, the interface sets: - EVF and BTF bits with an interrupt if the ITE bit is set. To close the communication: after writing the last byte to the DR register, set the STOP bit to generate the Stop condition. The interface goes automatically back to slave mode (M/SL bit cleared). Error Cases - BERR: Detection of a Stop or a Start condition during a byte transfer. In this case, the EVF and BERR bits are set by hardware with an interrupt if ITE is set. Note that BERR will not be set if an error is detected during the first or second pulse of each 9bit transaction: Single Master Mode If a Start or Stop is issued during the first or second pulse of a 9-bit transaction, the BERR flag will not be set and transfer will continue however the BUSY flag will be reset. To work around this, slave devices should issue a NACK when they receive a misplaced Start or Stop. The reception of a NACK or BUSY by the master in the middle 120/215 of communication gives the possibility to reinitiate transmission. Multimaster Mode Normally the BERR bit would be set whenever unauthorized transmission takes place while transfer is already in progress. However, an issue will arise if an external master generates an unauthorized Start or Stop while the I2C master is on the first or second pulse of a 9-bit transaction. It is possible to work around this by polling the BUSY bit during I2C master mode transmission. The resetting of the BUSY bit can then be handled in a similar manner as the BERR flag being set. - AF: Detection of a non-acknowledge bit. In this case, the EVF and AF bits are set by hardware with an interrupt if the ITE bit is set. To resume, set the Start or Stop bit. The AF bit is cleared by reading the I2CSR2 register. However, if read before the completion of the transmission, the AF flag will be set again, thus possibly generating a new interrupt. Software must ensure either that the SCL line is back at 0 before reading the SR2 register, or be able to correctly handle a second interrupt during the 9th pulse of a transmitted byte. - ARLO: Detection of an arbitration lost condition. In this case the ARLO bit is set by hardware (with an interrupt if the ITE bit is set and the interface goes automatically back to slave mode (the M/SL bit is cleared). Note: In all these cases, the SCL line is not held low; however, the SDA line can remain low due to possible 0 bits transmitted last. It is then necessary to release both lines by software. ST72F521, ST72521B I2C BUS INTERFACE (Cont'd) Figure 66. Transfer Sequencing 7-bit Slave receiver: S Address A Data1 A Data2 EV1 A EV2 EV2 ..... DataN A P EV2 EV4 7-bit Slave transmitter: S Address A Data1 A EV1 EV3 Data2 A EV3 EV3 DataN ..... NA P EV3-1 EV4 7-bit Master receiver: S Address A EV5 Data1 A EV6 Data2 A EV7 EV7 DataN ..... NA P EV7 7-bit Master transmitter: S Address A EV5 Data1 A EV6 EV8 Data2 A EV8 DataN ..... EV8 A P EV8 10-bit Slave receiver: S Header A Address A Data1 A EV1 ..... EV2 DataN A P EV2 EV4 10-bit Slave transmitter: Sr Header A Data1 A EV1 EV3 EV3 .... DataN . A P EV3-1 EV4 10-bit Master transmitter S Header EV5 A Address EV9 A Data1 A EV6 EV8 EV8 DataN ..... A P EV8 10-bit Master receiver: Sr Header EV5 A Data1 EV6 A EV7 ..... DataN A P EV7 Legend: S=Start, Sr = Repeated Start, P=Stop, A=Acknowledge, NA=Non-acknowledge, EVx=Event (with interrupt if ITE=1) EV1: EVF=1, ADSL=1, cleared by reading SR1 register. EV2: EVF=1, BTF=1, cleared by reading SR1 register followed by reading DR register. EV3: EVF=1, BTF=1, cleared by reading SR1 register followed by writing DR register. EV3-1: EVF=1, AF=1, BTF=1; AF is cleared by reading SR1 register. BTF is cleared by releasing the lines (STOP=1, STOP=0) or by writing DR register (DR=FFh). Note: If lines are released by STOP=1, STOP=0, the subsequent EV4 is not seen. EV4: EVF=1, STOPF=1, cleared by reading SR2 register. EV5: EVF=1, SB=1, cleared by reading SR1 register followed by writing DR register. EV6: EVF=1, cleared by reading SR1 register followed by writing CR register (for example PE=1). EV7: EVF=1, BTF=1, cleared by reading SR1 register followed by reading DR register. EV8: EVF=1, BTF=1, cleared by reading SR1 register followed by writing DR register. EV9: EVF=1, ADD10=1, cleared by reading SR1 register followed by writing DR register. 121/215 ST72F521, ST72521B I2C BUS INTERFACE (Cont'd) 10.7.5 Low Power Modes Mode WAIT HALT Description No effect on I2C interface. I2C interrupts cause the device to exit from WAIT mode. I2C registers are frozen. In HALT mode, the I2C interface is inactive and does not acknowledge data on the bus. The I2C interface resumes operation when the MCU is woken up by an interrupt with "exit from HALT mode" capability. 10.7.6 Interrupts Figure 67. Event Flags and Interrupt Generation ADD10 BTF ADSL SB AF STOPF ARLO BERR ITE INTERRUPT EVF * * EVF can also be set by EV6 or an error from the SR2 register. Interrupt Event 10-bit Address Sent Event (Master mode) End of Byte Transfer Event Address Matched Event (Slave mode) Start Bit Generation Event (Master mode) Acknowledge Failure Event Stop Detection Event (Slave mode) Arbitration Lost Event (Multimaster configuration) Bus Error Event Note: The I2C interrupt events are connected to the same interrupt vector (see Interrupts chapter). They generate an interrupt if the corresponding Enable Control Bit is set and the I-bit in the CC register is reset (RIM instruction). 122/215 Event Flag Enable Control Bit ADD10 BTF ADSEL SB AF STOPF ARLO BERR ITE Exit from Wait Yes Yes Yes Yes Yes Yes Yes Yes Exit from Halt No No No No No No No No ST72F521, ST72521B I2C BUS INTERFACE (Cont'd) 10.7.7 Register Description I2C CONTROL REGISTER (CR) Read / Write Reset Value: 0000 0000 (00h) - In slave mode: 0: No start generation 1: Start generation when the bus is free 7 0 0 0 PE ENGC START ACK STOP ITE Bit 2 = ACK Acknowledge enable. This bit is set and cleared by software. It is also cleared by hardware when the interface is disabled (PE=0). 0: No acknowledge returned 1: Acknowledge returned after an address byte or a data byte is received Bit 7:6 = Reserved. Forced to 0 by hardware. Bit 5 = PE Peripheral enable. This bit is set and cleared by software. 0: Peripheral disabled 1: Master/Slave capability Notes: - When PE=0, all the bits of the CR register and the SR register except the Stop bit are reset. All outputs are released while PE=0 - When PE=1, the corresponding I/O pins are selected by hardware as alternate functions. - To enable the I2C interface, write the CR register TWICE with PE=1 as the first write only activates the interface (only PE is set). Bit 4 = ENGC Enable General Call. This bit is set and cleared by software. It is also cleared by hardware when the interface is disabled (PE=0). The 00h General Call address is acknowledged (01h ignored). 0: General Call disabled 1: General Call enabled Note: In accordance with the I2C standard, when GCAL addressing is enabled, an I2C slave can only receive data. It will not transmit data to the master. Bit 3 = START Generation of a Start condition. This bit is set and cleared by software. It is also cleared by hardware when the interface is disabled (PE=0) or when the Start condition is sent (with interrupt generation if ITE=1). - In master mode: 0: No start generation 1: Repeated start generation Bit 1 = STOP Generation of a Stop condition. This bit is set and cleared by software. It is also cleared by hardware in master mode. Note: This bit is not cleared when the interface is disabled (PE=0). - In master mode: 0: No stop generation 1: Stop generation after the current byte transfer or after the current Start condition is sent. The STOP bit is cleared by hardware when the Stop condition is sent. - In slave mode: 0: No stop generation 1: Release the SCL and SDA lines after the current byte transfer (BTF=1). In this mode the STOP bit has to be cleared by software. Bit 0 = ITE Interrupt enable. This bit is set and cleared by software and cleared by hardware when the interface is disabled (PE=0). 0: Interrupts disabled 1: Interrupts enabled Refer to Figure 67 for the relationship between the events and the interrupt. SCL is held low when the ADD10, SB, BTF or ADSL flags or an EV6 event (See Figure 66) is detected. 123/215 ST72F521, ST72521B I2C BUS INTERFACE (Cont'd) I2C STATUS REGISTER 1 (SR1) Read Only Reset Value: 0000 0000 (00h) 1: Data byte transmitted 7 EVF 0 ADD10 TRA BUSY BTF ADSL M/SL SB Bit 7 = EVF Event flag. This bit is set by hardware as soon as an event occurs. It is cleared by software reading SR2 register in case of error event or as described in Figure 66. It is also cleared by hardware when the interface is disabled (PE=0). 0: No event 1: One of the following events has occurred: - BTF=1 (Byte received or transmitted) - ADSL=1 (Address matched in Slave mode while ACK=1) - SB=1 (Start condition generated in Master mode) - AF=1 (No acknowledge received after byte transmission) - STOPF=1 (Stop condition detected in Slave mode) - ARLO=1 (Arbitration lost in Master mode) - BERR=1 (Bus error, misplaced Start or Stop condition detected) - ADD10=1 (Master has sent header byte) - Address byte successfully transmitted in Master mode. Bit 6 = ADD10 10-bit addressing in Master mode. This bit is set by hardware when the master has sent the first byte in 10-bit address mode. It is cleared by software reading SR2 register followed by a write in the DR register of the second address byte. It is also cleared by hardware when the peripheral is disabled (PE=0). 0: No ADD10 event occurred. 1: Master has sent first address byte (header) Bit 5 = TRA Transmitter/Receiver. When BTF is set, TRA=1 if a data byte has been transmitted. It is cleared automatically when BTF is cleared. It is also cleared by hardware after detection of Stop condition (STOPF=1), loss of bus arbitration (ARLO=1) or when the interface is disabled (PE=0). 0: Data byte received (if BTF=1) 124/215 Bit 4 = BUSY Bus busy. This bit is set by hardware on detection of a Start condition and cleared by hardware on detection of a Stop condition. It indicates a communication in progress on the bus. The BUSY flag of the I2CSR1 register is cleared if a Bus Error occurs. 0: No communication on the bus 1: Communication ongoing on the bus Note: - The BUSY flag is NOT updated when the interface is disabled (PE=0). This can have consequences when operating in Multimaster mode; i.e. a second active I2C master commencing a transfer with an unset BUSY bit can cause a conflict resulting in lost data. A software workaround consists of checking that the I2C is not busy before enabling the I2C Multimaster cell. Bit 3 = BTF Byte transfer finished. This bit is set by hardware as soon as a byte is correctly received or transmitted with interrupt generation if ITE=1. It is cleared by software reading SR1 register followed by a read or write of DR register. It is also cleared by hardware when the interface is disabled (PE=0). - Following a byte transmission, this bit is set after reception of the acknowledge clock pulse. In case an address byte is sent, this bit is set only after the EV6 event (See Figure 66). BTF is cleared by reading SR1 register followed by writing the next byte in DR register. - Following a byte reception, this bit is set after transmission of the acknowledge clock pulse if ACK=1. BTF is cleared by reading SR1 register followed by reading the byte from DR register. The SCL line is held low while BTF=1. 0: Byte transfer not done 1: Byte transfer succeeded Bit 2 = ADSL Address matched (Slave mode). This bit is set by hardware as soon as the received slave address matched with the OAR register content or a general call is recognized. An interrupt is generated if ITE=1. It is cleared by software reading SR1 register or by hardware when the interface is disabled (PE=0). The SCL line is held low while ADSL=1. 0: Address mismatched or not received 1: Received address matched ST72F521, ST72521B I2C BUS INTERFACE (Cont'd) Bit 1 = M/SL Master/Slave. This bit is set by hardware as soon as the interface is in Master mode (writing START=1). It is cleared by hardware after detecting a Stop condition on the bus or a loss of arbitration (ARLO=1). It is also cleared when the interface is disabled (PE=0). 0: Slave mode 1: Master mode Bit 0 = SB Start bit (Master mode). This bit is set by hardware as soon as the Start condition is generated (following a write START=1). An interrupt is generated if ITE=1. It is cleared by software reading SR1 register followed by writing the address byte in DR register. It is also cleared by hardware when the interface is disabled (PE=0). 0: No Start condition 1: Start condition generated I2C STATUS REGISTER 2 (SR2) Read Only Reset Value: 0000 0000 (00h) 7 0 0 0 0 AF STOPF ARLO BERR GCAL Bit 7:5 = Reserved. Forced to 0 by hardware. Bit 4 = AF Acknowledge failure. This bit is set by hardware when no acknowledge is returned. An interrupt is generated if ITE=1. It is cleared by software reading SR2 register or by hardware when the interface is disabled (PE=0). The SCL line is not held low while AF=1 but by other flags (SB or BTF) that are set at the same time. 0: No acknowledge failure 1: Acknowledge failure Note: - When an AF event occurs, the SCL line is not held low; however, the SDA line can remain low if the last bits transmitted are all 0. It is then necessary to release both lines by software. Bit 3 = STOPF Stop detection (Slave mode). This bit is set by hardware when a Stop condition is detected on the bus after an acknowledge (if ACK=1). An interrupt is generated if ITE=1. It is cleared by software reading SR2 register or by hardware when the interface is disabled (PE=0). The SCL line is not held low while STOPF=1. 0: No Stop condition detected 1: Stop condition detected Bit 2 = ARLO Arbitration lost. This bit is set by hardware when the interface loses the arbitration of the bus to another master. An interrupt is generated if ITE=1. It is cleared by software reading SR2 register or by hardware when the interface is disabled (PE=0). After an ARLO event the interface switches back automatically to Slave mode (M/SL=0). The SCL line is not held low while ARLO=1. 0: No arbitration lost detected 1: Arbitration lost detected Note: - In a Multimaster environment, when the interface is configured in Master Receive mode it does not perform arbitration during the reception of the Acknowledge Bit. Mishandling of the ARLO bit from the I2CSR2 register may occur when a second master simultaneously requests the same data from the same slave and the I2C master does not acknowledge the data. The ARLO bit is then left at 0 instead of being set. Bit 1 = BERR Bus error. This bit is set by hardware when the interface detects a misplaced Start or Stop condition. An interrupt is generated if ITE=1. It is cleared by software reading SR2 register or by hardware when the interface is disabled (PE=0). The SCL line is not held low while BERR=1. 0: No misplaced Start or Stop condition 1: Misplaced Start or Stop condition Note: - If a Bus Error occurs, a Stop or a repeated Start condition should be generated by the Master to re-synchronize communication, get the transmission acknowledged and the bus released for further communication Bit 0 = GCAL General Call (Slave mode). This bit is set by hardware when a general call address is detected on the bus while ENGC=1. It is cleared by hardware detecting a Stop condition (STOPF=1) or when the interface is disabled (PE=0). 0: No general call address detected on bus 1: general call address detected on bus 125/215 ST72F521, ST72521B I2C BUS INTERFACE (Cont'd) I2C CLOCK CONTROL REGISTER (CCR) Read / Write Reset Value: 0000 0000 (00h) 7 FM/SM CC6 CC5 CC4 CC3 CC2 CC1 I2C DATA REGISTER (DR) Read / Write Reset Value: 0000 0000 (00h) 0 7 CC0 D7 Bit 7 = FM/SM Fast/Standard I2C mode. This bit is set and cleared by software. It is not cleared when the interface is disabled (PE=0). 0: Standard I2C mode 1: Fast I2C mode Bit 6:0 = CC[6:0] 7-bit clock divider. These bits select the speed of the bus (FSCL) depending on the I2C mode. They are not cleared when the interface is disabled (PE=0). Refer to the Electrical Characteristics section for the table of values. Note: The programmed FSCL assumes no load on SCL and SDA lines. 126/215 0 D6 D5 D4 D3 D2 D1 D0 Bit 7:0 = D[7:0] 8-bit Data Register. These bits contain the byte to be received or transmitted on the bus. - Transmitter mode: Byte transmission start automatically when the software writes in the DR register. - Receiver mode: the first data byte is received automatically in the DR register using the least significant bit of the address. Then, the following data bytes are received one by one after reading the DR register. ST72F521, ST72521B I2C BUS INTERFACE (Cont'd) I2C OWN ADDRESS REGISTER (OAR1) Read / Write Reset Value: 0000 0000 (00h) 7 ADD7 ADD6 ADD5 ADD4 ADD3 ADD2 ADD1 I2C OWN ADDRESS REGISTER (OAR2) Read / Write Reset Value: 0100 0000 (40h) 0 7 ADD0 FR1 7-bit Addressing Mode Bit 7:1 = ADD[7:1] Interface address. These bits define the I2C bus address of the interface. They are not cleared when the interface is disabled (PE=0). 0 FR0 0 0 0 ADD9 ADD8 0 Bit 7:6 = FR[1:0] Frequency bits. These bits are set by software only when the interface is disabled (PE=0). To configure the interface to I2C specified delays select the value corresponding to the microcontroller frequency FCPU. fCPU < 6 MHz 6 to 8 MHz FR1 0 0 FR0 0 1 Bit 0 = ADD0 Address direction bit. This bit is don't care, the interface acknowledges either 0 or 1. It is not cleared when the interface is disabled (PE=0). Note: Address 01h is always ignored. Bit 5:3 = Reserved 10-bit Addressing Mode Bit 7:0 = ADD[7:0] Interface address. These are the least significant bits of the I2C bus address of the interface. They are not cleared when the interface is disabled (PE=0). Bit 2:1 = ADD[9:8] Interface address. These are the most significant bits of the I2C bus address of the interface (10-bit mode only). They are not cleared when the interface is disabled (PE=0). Bit 0 = Reserved. 127/215 ST72F521, ST72521B IC BUS INTERFACE (Cont'd) Table 23. I2C Register Map and Reset Values Address (Hex.) Register Label 7 6 5 4 3 2 1 0 0018h I2CCR Reset Value 0 0 PE 0 ENGC 0 START 0 ACK 0 STOP 0 ITE 0 0019h I2CSR1 Reset Value EVF 0 ADD10 0 TRA 0 BUSY 0 BTF 0 ADSL 0 M/SL 0 SB 0 001Ah I2CSR2 Reset Value 0 0 0 AF 0 STOPF 0 ARLO 0 BERR 0 GCAL 0 001Bh I2CCCR Reset Value FM/SM 0 CC6 0 CC5 0 CC4 0 CC3 0 CC2 0 CC1 0 CC0 0 001Ch I2COAR1 Reset Value ADD7 0 ADD6 0 ADD5 0 ADD4 0 ADD3 0 ADD2 0 ADD1 0 ADD0 0 001Dh I2COAR2 Reset Value FR1 0 FR0 1 0 0 0 ADD9 0 ADD8 0 0 001Eh I2CDR Reset Value MSB 0 0 0 0 0 0 0 LSB 0 128/215 ST72F521, ST72521B 10.8 CONTROLLER AREA NETWORK (CAN) 10.8.1 Introduction This peripheral is designed to support serial data exchanges using a multi-master contention based priority scheme as described in CAN specification Rev. 2.0 part A. It can also be connected to a 2.0 B network without problems, since extended frames are checked for correctness and acknowledged accordingly although such frames cannot be transmitted nor received. The same applies to overload frames which are recognized but never initiated. Figure 68. CAN Block Diagram ST7 Internal Bus ST7 Interface TX/RX Buffer 1 TX/RX Buffer 2 TX/RX Buffer 3 ID Filter 0 ID Filter 1 10 Bytes 10 Bytes 10 Bytes 4 Bytes 4 Bytes PSR BRPR BTR RX BTL ICR SHREG BCDL ISR TX EML CRC CSR CAN 2.0B passive Core TECR RECR 129/215 ST72F521, ST72521B CONTROLLER AREA NETWORK (Cont'd) 10.8.2 Main Features - Support of CAN specification 2.0A and 2.0B passive - Three prioritized 10-byte Transmit/Receive message buffers - Two programmable global 12-bit message acceptance filters - Programmable baud rates up to 1 MBit/s - Buffer flip-flopping capability in transmission - Maskable interrupts for transmit, receive (one per buffer), error and wake-up - Automatic low-power mode after 20 recessive bits or on demand (standby mode) - Interrupt-driven wake-up from standby mode upon reception of dominant pulse - Optional dominant pulse transmission on leaving standby mode - Automatic message queuing for transmission upon writing of data byte 7 - Programmable loop-back mode for self-test operation - Advanced error detection and diagnosis functions - Software-efficient buffer mapping at a unique address space - Scalable architecture. 10.8.3 Functional Description 10.8.3.1 Frame Formats A summary of all the CAN frame formats is given in Figure 69 for reference. It covers only the standard frame format since the extended one is only acknowledged. A message begins with a start bit called Start Of Frame (SOF). This bit is followed by the arbitration field which contains the 11-bit identifier (ID) and the Remote Transmission Request bit (RTR). The RTR bit indicates whether it is a data frame or a remote request frame. A remote request frame does not have any data byte. The control field contains the Identifier Extension bit (IDE), which indicates standard or extended format, a reserved bit (ro) and, in the last four bits, a count of the data bytes (DLC). The data field ranges from zero to eight bytes and is followed by the Cyclic Redundancy Check (CRC) used as a frame integrity check for detecting bit errors. 130/215 The acknowledgement (ACK) field comprises the ACK slot and the ACK delimiter. The bit in the ACK slot is placed on the bus by the transmitter as a recessive bit (logical 1). It is overwritten as a dominant bit (logical 0) by those receivers which have at this time received the data correctly. In this way, the transmitting node can be assured that at least one receiver has correctly received its message. Note that messages are acknowledged by the receivers regardless of the outcome of the acceptance test. The end of the message is indicated by the End Of Frame (EOF). The intermission field defines the minimum number of bit periods separating consecutive messages. If there is no subsequent bus access by any station, the bus remains idle. 10.8.3.2 Hardware Blocks The CAN controller contains the following functional blocks (refer to Figure 68): - ST7 Interface: buffering of the ST7 internal bus and address decoding of the CAN registers. - TX/RX Buffers: three 10-byte buffers for transmission and reception of maximum length messages. - ID Filters: two 12-bit compare and don't care masks for message acceptance filtering. - PSR: page selection register (see memory map). - BRPR: clock divider for different data rates. - BTR: bit timing register. - ICR: interrupt control register. - ISR: interrupt status register. - CSR: general purpose control/status register. - TECR: transmit error counter register. - RECR: receive error counter register. - BTL: bit timing logic providing programmable bit sampling and bit clock generation for synchronization of the controller. - BCDL: bit coding logic generating a NRZ-coded datastream with stuff bits. - SHREG: 8-bit shift register for serialization of data to be transmitted and parallelisation of received data. - CRC: 15-bit CRC calculator and checker. - EML: error detection and management logic. - CAN Core: CAN 2.0B passive protocol controller. ST72F521, ST72521B CONTROLLER AREA NETWORK (Cont'd) Figure 69. CAN Frames Inter-Frame Space Inter-Frame Space or Overload Frame Data Frame 44 + 8 * N Arbitration Field Control Field Data Field 6 12 ID Ack Field 2 CRC Field 16 8*N EOF CRC ACK SOF RTR IDE r0 DLC 7 Inter-Frame Space or Overload Frame Remote Frame Inter-Frame Space 44 Arbitration Field Control Field CRC Field 6 12 ID 16 End Of Frame 7 CRC ACK RTR IDE r0 DLC SOF Data Frame or Remote Frame Ack Field 2 Inter-Frame Space or Overload Frame Error Frame Error Flag Flag Echo Error Delimiter 6 6 8 Inter-Frame Space Any Frame Data Frame or Remote Frame Notes: *0 <= N <= 8 * SOF = Start Of Frame Suspend Intermission Transmission 3 8 Bus Idle * ID = Identifier * RTR = Remote Transmission Request * IDE = Identifier Extension Bit * r0 = Reserved Bit End Of Frame or Error Delimiter or Overload Delimiter * DLC = Data Length Code Overload Frame Inter-Frame Space or Error Frame * CRC = Cyclic Redundancy Code * Error flag: 6 dominant bits if node is error active else 6 recessive bits. Overload Flag Overload Delimiter 6 8 * Suspend transmission: applies to error passive nodes only. * EOF = End of Frame * ACK = Acknowledge bit 131/215 ST72F521, ST72521B CONTROLLER AREA NETWORK (Cont'd) 10.8.3.3 Modes of Operation The CAN Core unit assumes one of the seven states described below: - STANDBY. Standby mode is entered either on a chip reset or on resetting the RUN bit in the Control/Status Register (CSR). Any on-going transmission or reception operation is not interrupted and completes normally before the Bit Time Logic and the clock prescaler are turned off for minimum power consumption. This state is signalled by the RUN bit being read-back as 0. Once in standby, the only event monitored is the reception of a dominant bit which causes a wakeup interrupt if the SCIE bit of the Interrupt Control Register (ICR) is set. The STANDBY mode is left by setting the RUN bit. If the WKPS bit is set in the CSR register, then the controller passes through WAKE-UP otherwise it enters RESYNC directly. It is important to note that the wake-up mechanism is software-driven and therefore carries a significant time overhead. All messages received after the wake-up bit and before the controller is set to run and has completed synchronization are ignored. Note: Standby mode is not entered on resetting the RUN bit in the Control/Status register (CSR) if the CANRX pin is shorted to GND. - WAKE-UP. The CAN bus line is forced to dominant for one bit time signalling the wake-up condition to all other bus members. Figure 70. CAN Controller State Diagram ARESET RUN & WKPS STANDBY RUN RUN & WKPS WAKE-UP RESYNC FSYN & BOFF & 11 Recessive bits | (FSYN | BOFF) & 128 * 11 Recessive bits RUN IDLE Write to DATA7 | TX Error & NRTX Start Of Frame TX OK RX OK Arbitration lost TRANSMISSION RECEPTION RX Error TX Error BOFF ERROR BOFF n 132/215 ST72F521, ST72521B CONTROLLER AREA NETWORK (Cont'd) - RESYNC. The resynchronization mode is used to find the correct entry point for starting transmission or reception after the node has gone asynchronous either by going into the STANDBY or bus-off states. Resynchronization is achieved when 128 sequences of 11 recessive bits have been monitored unless the node is not bus-off and the FSYN bit in the CSR register is set in which case a single sequence of 11 recessive bits needs to be monitored. - IDLE. The CAN controller looks for one of the following events: the RUN bit is reset, a Start Of Frame appears on the CAN bus or the DATA7 register of the currently active page is written to. - TRANSMISSION. Once the LOCK bit of a Buffer Control/Status Register (BCSRx) has been set and read back as such, a transmit job can be submitted by writing to the DATA7 register. The message with the highest priority will be transmitted as soon as the CAN bus becomes idle. Among those messages with a pending transmission request, the highest priority is given to Buffer 3 then 2 and 1. If the transmission fails due to a lost arbitration or to an error while the NRTX bit of the CSR register is reset, then a new transmission attempt is performed. This goes on until the transmission ends successfully or until the job is cancelled by unlocking the buffer, by setting the NRTX bit or if the node ever enters busoff or if a higher priority message becomes pending. The RDY bit in the BCSRx register, which was set since the job was submitted, gets reset. When a transmission is in progress, the BUSY bit in the BCSRx register is set. If it ends successfully then the TXIF bit in the Interrupt Status Register (ISR) is set, else the TEIF bit is set. An interrupt is generated in either case provided the TXIE and TEIE bits of the ICR register are set. Note 1: Setting the SRTE bit of the CSR register allows transmitted messages to be simultaneously received when they pass the acceptance filtering. This is particularly useful for checking the integrity of the communication path. RECEPTION. Once the CAN controller has synchronized itself onto the bus activity, it is ready for reception of new messages. Every incoming message gets its identifier compared to the acceptance filters. If the bitwise comparison of the selected bits ends up with a match for at least one of the filters then that message is elected for reception and a target buffer is searched for. This buffer will be the first one - order is 1 to 3 - that has the LOCK and RDY bits of its BCSRx register reset. - When no such buffer exists then an overrun interrupt is generated if the ORIE bit of the ICR register has been set. In this case the identifier of the last message is made available in the Last Identifier Register (LIDHR and LIDLR) at least until it gets overwritten by a new identifier picked-up from the bus. - When a buffer does exist, the accepted message gets written into it, the ACC bit in the BCSRx register gets the number of the matching filter, the RDY and RXIF bits get set and an interrupt is generated if the RXIE bit in the ISR register is set. Up to three messages can be automatically received without intervention from the CPU because each buffer has its own set of status bits, greatly reducing the reactiveness requirements in the processing of the receive interrupts. 133/215 ST72F521, ST72521B CONTROLLER AREA NETWORK (Cont'd) - ERROR. The error management as described in the CAN protocol is completely handled by hardware using 2 error counters which get incremented or decremented according to the error condition. Both of them may be read by the appli- cation to determine the stability of the network. Moreover, as one of the node status bits (EPSV or BOFF of the CSR register) changes, an interrupt is generated if the SCIE bit is set in the ICR Register. Refer to Figure 71. Figure 71. CAN Error State Diagram When TECR or RECR > 127, the EPSV bit gets set ERROR ACTIVE ERROR PASSIVE When TECR and RECR < 128, the EPSV bit gets cleared When 128 * 11 recessive bits occur: - the BOFF bit gets cleared - the TECR register gets cleared - the RECR register gets cleared When TECR > 255 the BOFF bit gets set and the EPSV bit gets cleared BUS OFF 134/215 ST72F521, ST72521B CONTROLLER AREA NETWORK (Cont'd) 10.8.3.4 Bit Timing Logic The bit timing logic monitors the serial bus-line and performs sampling and adjustment of the sample point by synchronizing on the start-bit edge and resynchronizing on following edges. Its operation may be explained simply when the nominal bit time is divided into three segments as follows: - Synchronisation segment (SYNC_SEG): a bit change is expected to lie within this time segment. It has a fixed length of one time quanta (1 x tCAN). - Bit segment 1 (BS1): defines the location of the sample point. It includes the PROP_SEG and PHASE_SEG1 of the CAN standard. Its duration is programmable between 1 and 16 time quanta but may be automatically lengthened to compensate for positive phase drifts due to differences in the frequency of the various nodes of the network. - Bit segment 2 (BS2): defines the location of the transmit point. It represents the PHASE_SEG2 of the CAN standard. Its duration is programmable between 1 and 8 time quanta but may also be automatically shortened to compensate for negative phase drifts. - Resynchronization Jump Width (RJW): defines an upper bound to the amount of lengthening or shortening of the bit segments. It is programmable between 1 and 4 time quanta. To guarantee the correct behaviour of the CAN controller, SYNC_SEG + BS1 + BS2 must be greater than or equal to 5 time quanta. The CAN controller resynchronizes on recessive to dominant edges only. For a detailed description of the CAN resynchronization mechanism and other bit timing configuration constraints, please refer to the Bosch CAN standard 2.0. As a safeguard against programming errors, the configuration of the Bit Timing Register (BTR) is only possible while the device is in STANDBY mode. Figure 72. Bit Timing NOMINAL BIT TIME SYNC_SEG 1 x tCAN BIT SEGMENT 1 (BS1) BIT SEGMENT 2 (BS2) tBS1 tBS2 SAMPLE POINT TRANSMIT POINT 135/215 ST72F521, ST72521B CONTROLLER AREA NETWORK (Cont'd) 10.8.4 Register Description The CAN registers are organized as 6 general purpose registers plus 5 pages of 16 registers spanning the same address space and primarily used for message and filter storage. The page actually selected is defined by the content of the Page Selection Register. 10.8.4.1 General Purpose Registers INTERRUPT STATUS REGISTER (ISR) Read/Write Reset Value: 00h 7 RXIF3 RXIF2 RXIF1 0 TXIF SCIF ORIF TEIF EPND Bit 7 = RXIF3 Receive Interrupt Flag for Buffer 3 - Read/Clear Set by hardware to signal that a new error-free message is available in buffer 3. Cleared by software to release buffer 3. Also cleared by resetting bit RDY of BCSR3. Bit 6 = RXIF2 Receive Interrupt Flag for Buffer 2 - Read/Clear Set by hardware to signal that a new error-free message is available in buffer 2. Cleared by software to release buffer 2. Also cleared by resetting bit RDY of BCSR2. Bit 5 = RXIF1 Receive Interrupt Flag for Buffer 1 - Read/Clear Set by hardware to signal that a new error-free message is available in buffer 1. Cleared by software to release buffer 1. Also cleared by resetting bit RDY of BCSR1. 136/215 Bit 4 = TXIF Transmit Interrupt Flag - Read/Clear Set by hardware to signal that the highest priority message queued for transmission has been successfully transmitted. Cleared by software. Bit 3 = SCIF Status Change Interrupt Flag - Read/Clear Set by hardware to signal the reception of a dominant bit while in standby mode. In Run mode this bit is set when EPVS is set or reset (refer to Figure 71. CAN Error State Diagram). This bit also signals any receive error when ESCI=1. Cleared by software. Bit 2 = ORIF Overrun Interrupt Flag - Read/Clear Set by hardware to signal that a message could not be stored because no receive buffer was available. Cleared by software. Bit 1 = TEIF Transmit Error Interrupt Flag - Read/Clear Set by hardware to signal that an error occurred during the transmission of the highest priority message queued for transmission. Cleared by software. Bit 0 = EPND Error Interrupt Pending - Read Only Set by hardware when at least one of the three error interrupt flags SCIF, ORIF or TEIF is set. Reset by hardware when all error interrupt flags have been cleared. Caution: Interrupt flags are reset by writing a "0" to the corresponding bit position. The appropriate way consists in writing an immediate mask or the one's complement of the register content initially read by the interrupt handler. Bit manipulation instruction BRES should never be used due to its read-modifywrite nature. ST72F521, ST72521B CONTROLLER AREA NETWORK (Cont'd) INTERRUPT CONTROL REGISTER (ICR) Read/Write Reset Value: 00h 7 0 0 ESCI RXIE TXIE SCIE ORIE TEIE 0 Bit 7 = Reserved. Bit 6 = ESCI Extended Status Change Interrupt - Read/Set/Clear Set by software to specify that SCIF is to be set on receive errors also. Cleared by software to set SCIF only on status changes and wake-up but not on all receive errors. Bit 5 = RXIE Receive Interrupt Enable - Read/Set/Clear Set by software to enable an interrupt request whenever a message has been received free of errors. Cleared by software to disable receive interrupt requests. Bit 4 = TXIE Transmit Interrupt Enable - Read/Set/Clear Set by software to enable an interrupt request whenever a message has been successfully transmitted. Cleared by software to disable transmit interrupt requests. Bit 3 = SCIE Status Change Interrupt Enable - Read/Set/Clear Set by software to enable an interrupt request whenever the node's status changes in run mode or whenever a dominant pulse is received in standby mode. Cleared by software to disable status change interrupt requests. Bit 2 = ORIE Overrun Interrupt Enable - Read/Set/Clear Set by software to enable an interrupt request whenever a message should be stored and no receive buffer is avalaible. Cleared by software to disable overrun interrupt requests. Bit 1 = TEIE Transmit Error Interrupt Enable - Read/Set/Clear Set by software to enable an interrupt whenever an error has been detected during transmission of a message. Cleared by software to disable transmit error interrupts. Bit 0 = Reserved. 137/215 ST72F521, ST72521B CONTROLLER AREA NETWORK (Cont'd) Bit 3 = NRTX No Retransmission CONTROL/STATUS REGISTER (CSR) Read/Write Reset Value: 00h 7 0 - Read/Set/Clear 0 BOFF EPSV SRTE NRTX FSYN WKPS RUN Bit 6 = BOFF Bus-Off State - Read Only Set by hardware to indicate that the node is in busoff state, i.e. the Transmit Error Counter exceeds 255. Reset by hardware to indicate that the node is involved in bus activities. Bit 5 = EPSV Error Passive State - Read Only Set by hardware to indicate that the node is error passive. Reset by hardware to indicate that the node is either error active (BOFF = 0) or bus-off. Bit 4 = SRTE Simultaneous Receive/Transmit Enable - Read/Set/Clear Set by software to enable simultaneous transmission and reception of a message passing the acceptance filtering. Allows to check the integrity of the communication path. Reset by software to discard all messages transmitted by the node. Allows remote and data frames to share the same identifier. 138/215 Set by software to disable the retransmission of unsuccessful messages. It does not stop transmission in case of Arbitration Lost. Cleared by software to enable retransmission of messages until success is met. Bit 2 = FSYN Fast Synchronization - Read/Set/Clear Set by software to enable a fast resynchronization when leaving standby mode, i.e. wait for only 11 recessive bits in a row. Cleared by software to enable the standard resynchronization when leaving standby mode, i.e. wait for 128 sequences of 11 recessive bits. Bit 1 = WKPS Wake-up Pulse - Read/Set/Clear Set by software to generate a dominant pulse when leaving standby mode. Cleared by software for no dominant wake-up pulse. Bit 0 = RUN CAN Enable - Read/Set/Clear Set by software to leave standby mode after 128 sequences of 11 recessive bits or just 11 recessive bits if FSYN is set. Cleared by software to request a switch to the standby or low-power mode as soon as any on-going transfer is complete. Read-back as 1 in the meantime to enable proper signalling of the standby state. The CPU clock may therefore be safely switched OFF whenever RUN is read as 0. ST72F521, ST72521B CONTROLLER AREA NETWORK (Cont'd) BAUD RATE PRESCALER REGISTER (BRPR) Read/Write in Standby mode Reset Value: 00h 7 RJW1 RJW0 BRP5 BRP4 BRP3 BRP2 BRP1 BIT TIMING REGISTER (BTR) Read/Write in Standby mode Reset Value: 23h 0 7 BRP0 0 RJW[1:0] determine the maximum number of time quanta by which a bit period may be shortened or lengthened to achieve resynchronization. tRJW = tCAN * (RJW + 1) BRP[5:0] determine the CAN system clock cycle time or time quanta which is used to build up the individual bit timing. tCAN = tCPU * (BRP + 1) Where tCPU = time period of the CPU clock. The resulting baud rate can be computed by the formula: 0 BS22 BS21 BS20 BS13 BS12 BS11 BS10 BS2[2:0] determine the length of Bit Segment 2. tBS2 = tCAN * (BS2 + 1) BS1[3:0] determine the length of Bit Segment 1. tBS1 = tCAN * (BS1 + 1) Note: Writing to this register is allowed only in Standby mode to prevent any accidental CAN protocol violation through programming errors. PAGE SELECTION REGISTER (PSR) Read/Write Reset Value: 00h 7 1 BR = --------------------------------------------------------------------------------------------------t CPU x ( BRP + 1 ) x ( BS1 + BS2 + 3 ) 0 0 0 0 0 PAGE PAGE PAGE 2 1 0 0 PAGE[2:0] determine which buffer or filter page is mapped at addresses 0010h to 001Fh. Note: Writing to this register is allowed only in Standby mode to prevent any accidental CAN protocol violation through programming errors. PAGE2 PAGE1 PAGE0 Page Title 0 0 0 Diagnosis 0 0 1 Buffer 1 0 1 0 Buffer 2 0 1 1 Buffer 3 1 0 0 Filters 1 0 1 Reserved 1 1 0 Reserved 1 1 1 Reserved 139/215 ST72F521, ST72521B CONTROLLER AREA NETWORK (Cont'd) 10.8.4.2 Paged Registers LAST IDENTIFIER HIGH REGISTER (LIDHR) Read/Write Reset Value: Undefined 7 LID10 0 LID9 LID8 LID7 LID6 LID5 LID4 LAST IDENTIFIER LOW REGISTER (LIDLR) Read/Write Reset Value: Undefined LID2 0 LID1 LID0 LRTR LDLC 3 LDLC 2 LDLC 1 7 TEC7 0 TEC6 TEC5 TEC4 TEC3 TEC2 TEC1 TEC0 LID3 LID[10:3] are the most significant 8 bits of the last Identifier read on the CAN bus. 7 TRANSMIT ERROR COUNTER REG. (TECR) Read Only Reset Value: 00h LDLC 0 TEC[7:0] is the least significant byte of the 9-bit Transmit Error Counter implementing part of the fault confinement mechanism of the CAN protocol. In case of an error during transmission, this counter is incremented by 8. It is decremented by 1 after every successful transmission. When the counter value exceeds 127, the CAN controller enters the error passive state. When a value of 256 is reached, the CAN controller is disconnected from the bus. RECEIVE ERROR COUNTER REG. (RECR) Page: 00h -- Read Only Reset Value: 00h 7 LID[2:0] are the least significant 3 bits of the last Identifier read on the CAN bus. LRTR is the last Remote Transmission Request bit read on the CAN bus. LDLC[3:0] is the last Data Length Code read on the CAN bus. REC7 0 REC6 REC5 REC4 REC3 REC2 REC1 REC0 REC[7:0] is the Receive Error Counter implementing part of the fault confinement mechanism of the CAN protocol. In case of an error during reception, this counter is incremented by 1 or by 8 depending on the error condition as defined by the CAN standard. After every successful reception the counter is decremented by 1 or reset to 120 if its value was higher than 128. When the counter value exceeds 127, the CAN controller enters the error passive state. IDENTIFIER HIGH REGISTERS (IDHRx) Read/Write Reset Value: Undefined 7 ID10 0 ID9 ID8 ID7 ID6 ID5 ID4 ID3 ID[10:3] are the most significant 8 bits of the 11-bit message identifier.The identifier acts as the message's name, used for bus access arbitration and acceptance filtering. 140/215 ST72F521, ST72521B CONTROLLER AREA NETWORK (Cont'd) BUFFER CONTROL/STATUS REGs. (BCSRx) Read/Write Reset Value: 00h IDENTIFIER LOW REGISTERS (IDLRx) Read/Write Reset Value: Undefined 7 ID2 ID1 ID0 RTR DLC3 DLC2 DLC1 0 7 DLC0 0 ID[2:0] are the least significant 3 bits of the 11-bit message identifier. RTR is the Remote Transmission Request bit. It is set to indicate a remote frame and reset to indicate a data frame. DLC[3:0] is the Data Length Code. It gives the number of bytes in the data field of the message.The valid range is 0 to 8. DATA REGISTERS (DATA0-7x) Read/Write Reset Value: Undefined 7 DATA 7 0 DATA 6 DATA 5 DATA 4 DATA 3 DATA 2 DATA 1 DATA 0 DATA[7:0] is a message data byte. Up to eight such bytes may be part of a message. Writing to byte DATA7 initiates a transmit request and should always be done even when DATA7 is not part of the message. 0 0 0 0 ACC RDY BUSY LOCK Bit 3 = ACC Acceptance Code - Read Only Set by hardware with the id of the highest priority filter which accepted the message stored in the buffer. ACC = 0: Match for Filter/Mask0. Possible match for Filter/Mask1. ACC = 1: No match for Filter/Mask0 and match for Filter/Mask1. Reset by hardware when either RDY or RXIF gets reset. Bit 2 = RDY Message Ready - Read/Clear Set by hardware to signal that a new error-free message is available (LOCK = 0) or that a transmission request is pending (LOCK = 1). Cleared by software when LOCK = 0 to release the buffer and to clear the corresponding RXIF bit in the Interrupt Status Register. Cleared by hardware when LOCK = 1 to indicate that the transmission request has been serviced or cancelled. Bit 1 = BUSY Busy Buffer - Read Only Set by hardware when the buffer is being filled (LOCK = 0) or emptied (LOCK = 1) and reset after the 2nd intermission bit. Reset by hardware when the buffer is not accessed by the CAN core for transmission nor reception purposes. Bit 0 = LOCK Lock Buffer - Read/Set/Clear Set by software to lock a buffer. No more message can be received into the buffer thus preserving its content and making it available for transmission. Cleared by software to make the buffer available for reception. Cancels any pending transmission request. Cleared by hardware once a message has been successfully transmitted provided the early transmit interrupt mode is on. Left untouched otherwise. Note that in order to prevent any message corruption or loss of context, LOCK cannot be set nor reset while BUSY is set. Trying to do so will result in LOCK not changing state. 141/215 ST72F521, ST72521B CONTROLLER AREA NETWORK (Cont'd) FILTER HIGH REGISTERS (FHRx) Read/Write Reset Value: Undefined MASK HIGH REGISTERS (MHRx) Read/Write Reset Value: Undefined 7 FIL11 0 FIL10 FIL9 FIL8 FIL7 FIL6 FIL5 FlL4 FIL[11:3] are the most significant 8 bits of a 12-bit message filter. The acceptance filter is compared bit by bit with the identifier and the RTR bit of the incoming message. If there is a match for the set of bits specified by the acceptance mask then the message is stored in a receive buffer. FILTER LOW REGISTERS (FLRx) Read/Write Reset Value: Undefined 7 FIL3 0 FIL2 FIL1 FIL0 0 0 0 0 7 0 MSK1 MSK1 MSK9 MSK8 MSK7 MSK6 MSK5 MSK4 1 0 MSK[11:3] are the most significant 8 bits of a 12bit message mask. The acceptance mask defines which bits of the acceptance filter should match the identifier and the RTR bit of the incoming message. MSKi = 0: don't care. MSKi = 1: match required. MASK LOW REGISTERS (MLRx) Read/Write Reset Value: Undefined 7 MSK3 MSK2 MSK1 MSK0 0 0 0 0 0 FIL[3:0] are the least significant 4 bits of a 12-bit message filter. MSK[3:0] are the least significant 4 bits of a 12-bit message mask. 142/215 ST72F521, ST72521B CONTROLLER AREA NETWORK (Cont'd) Figure 73. CAN Register Map 5Ah Interrupt Status 5Bh Interrupt Control 5Ch Control/Status 5Dh Baud Rate Prescaler 5Eh Bit Timing 5Fh Page Selection 60h 6Fh Paged Reg1 Paged Reg1 Paged Paged Reg1Reg0 Paged Reg2 Paged Paged Reg2Reg1 Paged Paged Reg2Reg1 Paged Reg3 Paged Paged Reg3Reg2 Paged Paged Reg3Reg2 Paged Reg4 Paged Paged Reg4Reg3 Paged Paged Paged Reg5Reg4Reg3 Paged Paged Reg5Reg4 Paged Paged Reg5Reg4 Paged Reg6 Paged Paged Reg6Reg5 Paged Paged Reg6Reg5 Paged Reg7 Paged Paged Reg7Reg6 Paged Paged Reg7Reg6 Paged Reg8 Paged Paged Reg8Reg7 Paged Paged Reg8Reg7 Paged Reg9 Paged Paged Reg9Reg8 Paged Paged Reg9Reg8 Paged Reg10 Paged Reg9 Paged Reg10 Paged Reg9 Paged Reg10 Paged Reg11 Paged Reg10 Paged Reg11 Paged Reg10 Paged Reg11 Paged Reg12 Paged Reg11 Paged Reg12 Paged Reg11 Paged Reg12 Paged Reg13 Paged Reg12 Paged Reg13 Paged Reg12 Paged Reg13 Paged Reg14 Paged Reg13 Paged Reg14 Paged Reg13 Paged Reg14 Paged Reg15 Paged Reg14 Paged Reg15 Paged Reg14 Paged Reg15 Paged Reg15 Paged Reg15 143/215 ST72F521, ST72521B CONTROLLER AREA NETWORK (Cont'd) Figure 74. Page Maps PAGE 0 PAGE 1 PAGE 2 PAGE 3 PAGE 4 60h LIDHR IDHR1 IDHR2 IDHR3 FHR0 61h LIDLR IDLR1 IDLR2 IDLR3 FLR0 62h DATA01 DATA02 DATA03 MHR0 63h DATA11 DATA12 DATA13 MLR0 64h DATA21 DATA22 DATA23 FHR1 65h DATA31 DATA32 DATA33 FLR1 66h DATA41 DATA42 DATA43 MHR1 DATA51 DATA52 DATA53 MLR1 68h DATA61 DATA62 DATA63 69h DATA71 DATA72 DATA73 Reserved Reserved Reserved 67h Reserved 6Ah 6Bh Reserved 6Ch 6Dh 6Eh TECR 6Fh RECR BCSR1 BCSR2 BCSR3 Diagnosis Buffer 1 Buffer 2 Buffer 3 144/215 Acceptance Filters ST72F521, ST72521B CONTROLLER AREA NETWORK (Cont'd) Table 24. CAN Register Map and Reset Values Address (Hex.) Page 5A 5B 5C 5D 5E 5F 0 60 1 to 3 60, 64 4 0 61 1 to 3 61, 65 4 62 to 69 1 to 3 62, 66 4 63, 67 4 6E 0 6F 1 to 3 Register Label CANISR Reset Value CANICR Reset Value CANCSR Reset Value CANBRPR Reset Value CANBTR Reset Value CANPSR Reset Value CANLIDHR Reset Value CANIDHRx Reset Value CANFHRx Reset Value CANLIDLR Reset Value CANIDLRx Reset Value CANFLRx Reset Value CANDRx Reset Value CANMHRx Reset Value CANMLRx Reset Value CANTECR Reset Value CANRECR Reset Value CANBCSRx Reset Value 7 6 5 4 3 2 1 0 RXIF3 0 RXIF2 0 ESCI 0 BOFF 0 RJW0 0 BS22 0 RXIF1 0 RXIE 0 EPSV 0 BRP5 0 BS21 1 TXIF 0 TXIE 0 SRTE 0 BRP4 0 BS20 0 SCIF 0 SCIE 0 NRTX 0 BRP3 0 BS13 0 0 LID9 x ID9 x FIL10 x LID1 x ID1 x FIL2 x 0 LID8 x ID8 x FIL9 x LID0 x ID0 x FIL1 x 0 LID7 x ID7 x FIL8 x LRTR x RTR x FIL0 x 0 LID6 x ID6 x FIL7 x LDLC3 x DLC3 x ORIF 0 ORIE 0 FSYN 0 BRP2 0 BS12 0 PAGE2 0 LID5 x ID5 x FIL6 x LDLC2 x DLC2 x TEIF 0 TEIE 0 WKPS 0 BRP1 0 BS11 1 PAGE1 0 LID4 x ID4 x FIL5 x LDLC1 x DLC1 x EPND 0 ETX 0 RUN 0 BRP0 0 BS10 1 PAGE0 0 LID3 x ID3 x FIL4 x LDLC0 x DLC0 x 0 0 0 x MSK10 x MSK2 x x MSK9 x MSK1 x x MSK8 x MSK0 x x MSK7 x x MSK6 x x MSK5 x 0 LSB x MSK4 x 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ACC 0 0 RDY 0 0 BUSY 0 0 0 RJW1 0 0 0 LID10 x ID10 x FIL11 x LID2 x ID2 x FIL3 x MSB x MSK11 x MSK3 x MSB 0 MSB 0 0 0 LSB 0 LSB 0 LOCK 0 145/215 ST72F521, ST72521B CONTROLLER AREA NETWORK (Cont'd) 10.8.5 List of CAN Cell Limitations 10.8.5.1 Omitted SOF bit Symptom: Start of Frame (SOF) bit is omitted if transmission is requested in the last Intermission bit. Test Case: 5.3.1 10-Kbit Stress Test Details: The IUT is requested to start transmission immediately after the completion of the previous transmission. The LT also starts its transmission and asserts the SOF bit just after the 3rd Intermission bit. The IUT also starts transmission but omits the SOF bit. The IUT wins the arbitration and continues the transmission. The frame is sent correctly. Impact On The Application: As this effect only occurs when the IUT detects a SOF bit on the CAN bus, the fact that it omits its own SOF bit has no impact on the communication. 10.8.5.2 CAN: CPU Write Access (More Than One Cycle) Corrupts CAN Frame Symptoms: For CAN received messages the identifier high byte or last data byte can be corrupted. 146/215 For CAN transmitted messages the 2nd data byte can be corrupted. Details: The CAN transmit and receive buffers are implemented as dual ported RAM. During the reception of a CAN frame the CAN core writes the received identifier and the data byte-by-byte in the corresponding buffer. IF the CAN bit timing configuration is tBS2 < 5 time quanta AND IF concurrently with the pCAN, the CPU executes a write access to the dual ported RAM using an instruction with more than one cycle access, e.g. CLR, BSET, BRES THEN the access conflict can lead to the corruption described in the symptoms paragraph above. Impact On The Application: Several CAN frames with erroneous data or identifier will be received/transmitted. Software Workaround: Program tBS2 > 4 time quanta or, when accessing the receive or transmit buffers, do not use the critical instructions which are: BSET, BRES, CLR, CPL, DEC, INC, NEG, RLC, SLL, SRL, RRC, SRA, SWAP. ST72F521, ST72521B CONTROLLER AREA NETWORK (Cont'd) 10.8.5.3 Unexpected message transmission Symptom: The previous message received by pCAN, even if this message did not pass the receive filter, will be retransmitted by pCAN with a correct identifier and DLC but with corrupted data. The data bytes will be a copy of the identifier bytes IDHR and IDLR in the following repetitive pattern: DATA_0 = IDHR DATA_1 = IDLR DATA_2 = IDHR DATA_3 = IDLR etc. DATA_7 = IDLR If no message has been received before the problem occurs then identifier byte values are random but the data bytes are in the same repetitive pattern. Details: The buffers of the pCAN cell are configurable as receive or transmit buffers. By default, all buffers are configured in reception. To use a buffer to transmit a CAN message the application has to reserve this buffer for transmission by setting the LOCK bit in the BCSR register. So the buffer is then locked for any further reception and reserved for transmission. Once a transmission has been requested by a write access to data byte 7 of the buffer the appli- cation might need to abort this transmission request. To do so, the application can reset the LOCK bit in the BCSR register. If the message is pending (RDY bit set) but not currently being transmitted, then clearing the LOCK bit will abort it immediately. If the message is pending (RDY bit set) and currently being transmitted then the message will not be interrupted but the CAN core will wait until the end of this transmission attempt. Then software must clear the LOCK bit again to abort the transmission. An unexpected transmission can occur: IF the application resets the LOCK bit WHILE the CAN core is preparing the transmission1) AND there is no other transmission pending in another buffer THEN the LOCK bit is reset but the transmission is not stopped. Instead the content of the page 0 buffer will be transmitted. Impact On The Application: pCAN will echo some messages sent by other nodes. Identifier and DLC will be correct but data are corrupted as described previously. Note 1: The preparation lasts two bit times just before SOF, this is the critical window during which the LOCK bit must not be reset by the application. 147/215 ST72F521, ST72521B CONTROLLER AREA NETWORK (Cont'd) Software Work-around - Devices with HardTo abort the transmission, first the application sets ware Fix (ST72F521 rev "R"): the WKPS bit and polls it until it is set. The maximum time needed to set this bit is two CAN bit To implement a transmission abort under safe times. Once the application has read the WKPS bit conditions, the LOCK bit must not be reset during as one, it can reset the LOCK bit to stop the curthe critical window (2 bit times). A new function rent transmission. has been implemented in the MCU allowing the application to synchronize the reset of the LOCK The abort is completed when the LOCK bit is read bit (abort request) with the reset of the TXRQST bit back as zero by the application. Once the abort (internal signal) in the pCAN core. has been completed, the application must reset the WKPS bit to be able to transmit again. Of The synchronization is done using the WKPS bit in course the transmit buffer must be in LOCK state the CANCSR register, the function of this bit has as usual before any transmission attempt. been modified and no more Wake-up Pulse (dominant bit) is sent on the CAN_TX signal when the The "C" code sequence below shows the software WKPS bit is set. This means the functionality dework-around using the WKPS bit. scribed in the datasheet is no longer applicable (see Section 10.8.5.4). CANCSR |= WKPS; // Set WKPS bit while(!(CANCSR & WKPS) );// Wait until WKPS bit is set while( CANBCSR & LOCK )// Wait until abort has been confirmed { CANBCSR &= ~LOCK; } CANCSR &= ~WKPS; // Allow transmission again CANBCSR |= LOCK; //Alloc buffer for next transmission 148/215 ST72F521, ST72521B CONTROLLER AREA NETWORK (Cont'd) Software Work-around - Devices without Hardware Fix: To implement a transmission abort under safe conditions, any reset of the LOCK bit during the critical window (2 bit times) must be avoided. Two different cases have to be considered, either the pCAN enters standby mode after the abort, or the abort is performed and pCAN keeps running. Abort followed by STANDBY mode (RUN=0) In this case, aborting the pending transmissions can safely be done by first entering STANDBY mode and then releasing the transmit buffers. STANDBY mode is entered by resetting the RUN bit in the CSR register and once the current transmission attempt, even if it fails due to error or lost arbitration, has been performed, pCAN enters STANDBY mode (RUN=0). Once in STANDBY mode the application can abort all pending transmissions by resetting the corresponding LOCK bit. Abort while staying in RUN mode (RUN=1) Contrary to the STANDBY case described previously, in the RUN case the application has to handle the error or arbitration lost conditions. In case of transmission errors, causing the frame to be transmitted again and again, the application must set the NRTX bit in the CSR register. This will cause pCAN to abort the transmission at the end of the current attempt. In case of arbitration lost, setting the NRTX bit does not abort the transmission, therefore the application must reset the LOCK bit to abort the transmission. To avoid resetting the LOCK bit during the critical time window, leading to the problem described at the start of this section, the application must monitor the BUSY bit in the BCSR register and reset the LOCK bit just after the falling edge of the BUSY bit. The time between the falling edge of the BUSY bit and the SOF of the next transmission attempt is in any case long enough to guarantee that the LOCK bit is reset before the critical time window. The "C" code sequence below shows the software work-around for both the error and arbitration lost cases. _asm("SIM\n"); // Mask interrupts CANCSR |= NRTX; // Set non automatic retransmission bit while(!(CANBCSR & BUSY) &&// Wait till BUSY bit is set (CANBCSR & RDY) ); // or transmission done while( CANBCSR & BUSY ); // Wait till BUSY bit is reset (falling edge) if( CANBCSR & RDY ) { // transmission still pending -> must be aborted CANBCSR &= ~LOCK; //Arbitration lost => cancel transmission safel while( CANBCSR & RDY );// Wait for unlock confirmed CANCSR &= ~NRTX;// Reset NRTX bit once abort sequence done _asm("RIM\n"); } else { // No more abort required as RDY bit already reset CANCSR &= ~NRTX;// Reset NRTX bit once abort sequence done _asm("RIM\n"); // Enable interrupts } 149/215 ST72F521, ST72521B Figure 75. Work-around Flowchart Application Requests an Abort YES READY == 1 NO MASK INT SET NRTX YES BUSY == 0 AND READY == 1 YES YES NO BUSY == 0 NO READY == 1 RESET LOCK NO YES READY == 1 SET LOCK RESET NRTX ENABLE INT Abort Done 150/215 NO ST72F521, ST72521B CONTROLLER AREA NETWORK (Cont'd) The figures below show the abort behaviour in the four possible cases. the error (the first attempt). The abort has been successful and the transmit buffer is empty. Figure 76. Abort and successful transmission Figure 79. Abort and arbitration lost TX RQST TX RQST ABORT RQST ABORT RQST CAN TX CAN TX CAN RX CAN RX LOCK LOCK READY READY BUSY BUSY NRTX NRTX In this case the abort request performed during the transmission has no effect, as the first transmission is successful. Figure 77. Abort and transmission delayed by busy CAN bus TX RQST ABORT RQST CAN TX CAN RX LOCK READY BUSY NRTX In this case the NRTX bit is set to abort the transmission after the first attempt. As the first attempt is successful the READY and BUSY bits are reset by pCAN and the transmit buffer becomes empty. An abort is no longer required. Figure 78. Abort and error during transmission TX RQST ABORT RQST Error CAN TX CAN RX LOCK READY BUSY NRTX In this case the NRTX bit is set but has no effect, as the previous transmission attempt failed due to an arbitration lost. The application waits for the falling edge of BUSY bit and checks that READY is still set. This is the case, this means pCAN has lost the arbitration and LOCK bit can be safely reset. Abort is immediate and pCAN resets the READY and BUSY bits. Timing Considerations As no interrupt signals that an abort has been successful, the application has to wait until the transmit buffer is empty (transmission has been aborted or transmitted successfully). This time can vary depending on the case in which the abort is performed (arbitration lost, error or successful transmission). To show the impact of the software workaround on this timing behaviour Figure 80 and Figure 81 compare the reference behaviour (worst case when abort is done by LOCK only) with the behaviour when NRTX, BUSY and LOCK bits are used. Figure 80. Abort by LOCK only - Reference behaviour TX RQST ABORT RQST CAN TX CAN RX LOCK READY BUSY NRTX In this case NRTX (abort request) is set before the error, thus pCAN resets READY and BUSY after 151/215 ST72F521, ST72521B CONTROLLER AREA NETWORK (Cont'd) The worst case is when the abort request is done when the transmission has just started. In this case the LOCK bit cannot be reset as long as the BUSY bit is set, this means until the end of the frame. So the application will wait for READY to be reset during the whole frame and in this case the worst case will be the longest frame the application is expected to transmit. Figure 81. Abort with the software work-around - by NRTX, BUSY and LOCK TX RQST ABORT RQST CAN TX CAN RX LOCK reset. If the next arbitration is won by pCAN then the BUSY bit will be reset by the end of the successful transmission. The longest time the application has to wait in this case is the time of the longest message expected on the bus (minus identifier) plus the longest message expected to be transmitted by the application. This roughly double the time the application may have to wait before the abort sequence is performed. 10.8.5.4 WKPS Functionality Due to a fix implemented to solve the "Unexpected Message Transmission" issue (see Section 10.8.5.3) the WKPS functionality has been modified as follows in Flash ST72F521 devices: Device READY BUSY NRTX Using the software work-around the worst case occurs in the arbitration lost case. If the abort is requested just after pCAN has lost the arbitration then the application has to wait for the next falling edge of the BUSY bit before the LOCK bit can be 152/215 Flash ST72F521 Rev R Modification WKPS bit does not generate a wakeup pulse. It is used to synchronize the reset of the LOCK bit (see "Software Work-around - Devices with Hardware Fix (ST72F521 rev "R"):" on page 148) ROM WKPS bit functions according to the ST72521 All datasheet description. revisions ST72F521, ST72521B CONTROLLER AREA NETWORK (Cont'd) 10.8.5.5 Bus-off state not entered Symptom: pCAN does not enter bus-off state under certain conditions. This is fixed in FLASH version of ST72F521 starting from silicon Rev R and in ROM version ST72521B starting from silicon Rev Y. Details: According to the CAN standard, pCAN is expected to enter bus-off state when TEC (Transmit Error Counter) is greater than 255. But if REC (Receive Error Counter) is greater than 127 (Error Passive State) pCAN does not enter bus-off and the BOFF bit of the CSR register is not set. To enter bus-off, REC must decrease to a val- ue lower than 128, this is the case with any correct reception even if the message is filtered out. As bus-off state is not entered and pCAN still attempts to transmit its message, after the overflow the TEC register continues to increment as long as transmission errors occur. Impact on the application: The application will not stop attempting to transmit CAN messages, even when the bus-off conditions have been reached, until the transmission has been successful or the value of REC becomes lower than 128. However the application will not disturb the communication of the other nodes on the CAN network as pCAN is in Error Passive State. Figure 82. CAN Error State Diagram showing "BUSOFF not entered" limitation When TECR or RECR > 127, the EPSV bit gets set ERROR ACTIVE ERROR PASSIVE When TECR and RECR < 128, the EPSV bit gets cleared When 128 * 11 recessive bits occur: - the BOFF bit gets cleared - the TECR register gets cleared - the RECR register gets cleared When TECR > 255 and RECR < 128 the BOFF bit gets set and the EPSV bit gets cleared BUS OFF 153/215 ST72F521, ST72521B CONTROLLER AREA NETWORK (Cont'd) Workaround Description to reach 256 the sequence must be executed 32 times. Under these conditions the shortest seThe bus-off entry works correctly in almost all casquence leading to a TEC overflow lasts 832 bit es, only when REC is greater than 127 a bus-off times. will not be recognized by pCAN. Therefore the pCAN bus-off signalling (BOFF) is still used but it Depending on the baudrate the application will needs to be complemented by monitoring TEC by have to adapt the monitoring period, for example software. at 500kbps the period must be less than 1600us. To detect the bus-off condition by software the apThe `C' code below shows an implementation explication has to monitor the value of the TEC regample of the monitoring sequence. This code is ister periodically. An overflow signals a bus-off called periodically as described above. condition. When a bus-off condition has been deTo detect the overflow, the test condition must tected the application must execute the following take into account that TEC might also have been sequence to recover from bus-off properly: the apdecremented due to a successful transmission. So plication stops pCAN by clearing the RUN bit in the an overflow condition is detected: CANCSR register resets all pending transmission IF the current TEC value is lower than the previous by clearing the LOCK bit in the BCSR register and TEC value starts it again by setting the RUN bit. AND the difference is greater than the number of To detect the bus-off condition properly, the TEC possible successful transmissions during the monmonitoring period must be lower than the time beitoring period. tween two overflows. As the problem only occurs when pCAN is in Error Passive State (REC > 127) In the example above, one message can be sent, pCAN will continuously try to send a SOF followed therefore one is added to CANTECR. by an Error Passive Flag and a Suspend Transmission. This leads to 26 (1 + 6 + 8 + 3 + 8) bit times. Each time TEC is incremented by 8, hence ************************************************/ /* INITIALISATION /************************************************/ unsigned char TECReg=0; //Previous value of TEC unsigned char BusOffFlag=0; //Set to one if bus-off /************************************************/ /* BUS-OFF MONITORING SEQUENCE /************************************************/ if( (CANCSR & BOFF) || ( CANTECR+1 < TECReg) ) { BusOffFlag = 1; } else { TECReg = CANTECR; } 154/215 ST72F521, ST72521B 10.9 10-BIT A/D CONVERTER (ADC) 10.9.1 Introduction The on-chip Analog to Digital Converter (ADC) peripheral is a 10-bit, successive approximation converter with internal sample and hold circuitry. This peripheral has up to 16 multiplexed analog input channels (refer to device pin out description) that allow the peripheral to convert the analog voltage levels from up to 16 different sources. The result of the conversion is stored in a 10-bit Data Register. The A/D converter is controlled through a Control/Status Register. 10.9.2 Main Features 10-bit conversion Up to 16 channels with multiplexed input Linear successive approximation Data register (DR) which contains the results Conversion complete status flag On/off bit (to reduce consumption) The block diagram is shown in Figure 83. Figure 83. ADC Block Diagram fCPU DIV 4 0 DIV 2 fADC 1 EOC SPEED ADON 0 CH3 CH2 CH1 CH0 ADCCSR 4 AIN0 AIN1 ANALOG TO DIGITAL ANALOG MUX CONVERTER AINx ADCDRH D9 D8 ADCDRL D7 0 D6 0 D5 0 D4 0 D3 0 D2 0 D1 D0 155/215 ST72F521, ST72521B 10-BIT A/D CONVERTER (ADC) (Cont'd) 10.9.3 Functional Description The conversion is monotonic, meaning that the result never decreases if the analog input does not and never increases if the analog input does not. If the input voltage (VAIN) is greater than VAREF (high-level voltage reference) then the conversion result is FFh in the ADCDRH register and 03h in the ADCDRL register (without overflow indication). If the input voltage (VAIN) is lower than VSSA (lowlevel voltage reference) then the conversion result in the ADCDRH and ADCDRL registers is 00 00h. The A/D converter is linear and the digital result of the conversion is stored in the ADCDRH and ADCDRL registers. The accuracy of the conversion is described in the Electrical Characteristics Section. RAIN is the maximum recommended impedance for an analog input signal. If the impedance is too high, this will result in a loss of accuracy due to leakage and sampling not being completed in the alloted time. 10.9.3.1 A/D Converter Configuration The analog input ports must be configured as input, no pull-up, no interrupt. Refer to the I/O ports chapter. Using these pins as analog inputs does not affect the ability of the port to be read as a logic input. In the ADCCSR register: - Select the CS[3:0] bits to assign the analog channel to convert. 10.9.3.2 Starting the Conversion In the ADCCSR register: - Set the ADON bit to enable the A/D converter and to start the conversion. From this time on, the ADC performs a continuous conversion of the selected channel. When a conversion is complete: - The EOC bit is set by hardware. - The result is in the ADCDR registers. A read to the ADCDRH resets the EOC bit. 156/215 To read the 10 bits, perform the following steps: 1. Poll the EOC bit 2. Read the ADCDRL register 3. Read the ADCDRH register. This clears EOC automatically. Note: The data is not latched, so both the low and the high data register must be read before the next conversion is complete, so it is recommended to disable interrupts while reading the conversion result. To read only 8 bits, perform the following steps: 1. Poll the EOC bit 2. Read the ADCDRH register. This clears EOC automatically. 10.9.3.3 Changing the conversion channel The application can change channels during conversion. When software modifies the CH[3:0] bits in the ADCCSR register, the current conversion is stopped, the EOC bit is cleared, and the A/D converter starts converting the newly selected channel. 10.9.4 Low Power Modes Note: The A/D converter may be disabled by resetting the ADON bit. This feature allows reduced power consumption when no conversion is needed and between single shot conversions. Mode WAIT HALT Description No effect on A/D Converter A/D Converter disabled. After wakeup from Halt mode, the A/D Converter requires a stabilization time tSTAB (see Electrical Characteristics) before accurate conversions can be performed. 10.9.5 Interrupts None. ST72F521, ST72521B 10-BIT A/D CONVERTER (ADC) (Cont'd) 10.9.6 Register Description CONTROL/STATUS REGISTER (ADCCSR) Read/Write (Except bit 7 read only) Reset Value: 0000 0000 (00h) 7 EOC SPEED ADON Bit 3:0 = CH[3:0] Channel Selection These bits are set and cleared by software. They select the analog input to convert. 0 0 CH3 CH2 CH1 CH0 Bit 7 = EOC End of Conversion This bit is set by hardware. It is cleared by hardware when software reads the ADCDRH register or writes to any bit of the ADCCSR register. 0: Conversion is not complete 1: Conversion complete Bit 6 = SPEED ADC clock selection This bit is set and cleared by software. 0: fADC = fCPU/4 1: fADC = fCPU/2 Bit 5 = ADON A/D Converter on This bit is set and cleared by software. 0: Disable ADC and stop conversion 1: Enable ADC and start conversion Bit 4 = Reserved. Must be kept cleared. Channel Pin* CH3 CH2 CH1 CH0 AIN0 AIN1 AIN2 AIN3 AIN4 AIN5 AIN6 AIN7 AIN8 AIN9 AIN10 AIN11 AIN12 AIN13 AIN14 AIN15 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 *The number of channels is device dependent. Refer to the device pinout description. DATA REGISTER (ADCDRH) Read Only Reset Value: 0000 0000 (00h) 7 D9 0 D8 D7 D6 D5 D4 D3 D2 Bit 7:0 = D[9:2] MSB of Converted Analog Value DATA REGISTER (ADCDRL) Read Only Reset Value: 0000 0000 (00h) 7 0 0 0 0 0 0 0 D1 D0 Bit 7:2 = Reserved. Forced by hardware to 0. Bit 1:0 = D[1:0] LSB of Converted Analog Value 157/215 ST72F521, ST72521B 10-BIT A/D CONVERTER (Cont'd) Table 25. ADC Register Map and Reset Values Address (Hex.) Register Label 7 6 5 4 3 2 1 0 0070h ADCCSR Reset Value EOC 0 SPEED 0 ADON 0 0 CH3 0 CH2 0 CH1 0 CH0 0 0071h ADCDRH Reset Value D9 0 D8 0 D7 0 D6 0 D5 0 D4 0 D3 0 D2 0 0072h ADCDRL Reset Value 0 0 0 0 0 0 D1 0 D0 0 158/215 ST72F521, ST72521B 11 INSTRUCTION SET 11.1 CPU ADDRESSING MODES The CPU features 17 different addressing modes which can be classified in 7 main groups: Addressing Mode Example Inherent nop Immediate ld A,#$55 Direct ld A,$55 Indexed ld A,($55,X) Indirect ld A,([$55],X) Relative jrne loop Bit operation bset byte,#5 The CPU Instruction set is designed to minimize the number of bytes required per instruction: To do so, most of the addressing modes may be subdivided in two sub-modes called long and short: - Long addressing mode is more powerful because it can use the full 64 Kbyte address space, however it uses more bytes and more CPU cycles. - Short addressing mode is less powerful because it can generally only access page zero (0000h 00FFh range), but the instruction size is more compact, and faster. All memory to memory instructions use short addressing modes only (CLR, CPL, NEG, BSET, BRES, BTJT, BTJF, INC, DEC, RLC, RRC, SLL, SRL, SRA, SWAP) The ST7 Assembler optimizes the use of long and short addressing modes. Table 26. CPU Addressing Mode Overview Mode Syntax Destination Pointer Address (Hex.) Pointer Size (Hex.) Length (Bytes) Inherent nop +0 Immediate ld A,#$55 +1 Short Direct ld A,$10 00..FF +1 Long Direct ld A,$1000 0000..FFFF +2 No Offset Direct Indexed ld A,(X) 00..FF +0 Short Direct Indexed ld A,($10,X) 00..1FE +1 Long Direct Indexed ld A,($1000,X) 0000..FFFF +2 Short Indirect ld A,[$10] 00..FF 00..FF byte +2 Long Indirect ld A,[$10.w] 0000..FFFF 00..FF word +2 Short Indirect Indexed ld A,([$10],X) 00..1FE 00..FF byte +2 Long Indirect Indexed ld A,([$10.w],X) 0000..FFFF 00..FF word +2 Relative Direct jrne loop PC+/-127 Relative Indirect jrne [$10] PC+/-127 Bit Direct bset $10,#7 00..FF Bit Indirect bset [$10],#7 00..FF Bit Direct Relative btjt $10,#7,skip 00..FF Bit Indirect Relative btjt [$10],#7,skip 00..FF +1 00..FF byte +2 +1 00..FF byte +2 +2 00..FF byte +3 159/215 ST72F521, ST72521B INSTRUCTION SET OVERVIEW (Cont'd) 11.1.1 Inherent All Inherent instructions consist of a single byte. The opcode fully specifies all the required information for the CPU to process the operation. Inherent Instruction Function NOP No operation TRAP S/W Interrupt WFI Wait For Interrupt (Low Power Mode) HALT Halt Oscillator (Lowest Power Mode) RET Sub-routine Return IRET Interrupt Sub-routine Return SIM Set Interrupt Mask (level 3) RIM Reset Interrupt Mask (level 0) SCF Set Carry Flag RCF Reset Carry Flag RSP Reset Stack Pointer LD Load CLR Clear PUSH/POP Push/Pop to/from the stack INC/DEC Increment/Decrement TNZ Test Negative or Zero CPL, NEG 1 or 2 Complement MUL Byte Multiplication SLL, SRL, SRA, RLC, RRC Shift and Rotate Operations SWAP Swap Nibbles 11.1.2 Immediate Immediate instructions have two bytes, the first byte contains the opcode, the second byte contains the operand value. Immediate Instruction LD Function Load CP Compare BCP Bit Compare AND, OR, XOR Logical Operations ADC, ADD, SUB, SBC Arithmetic Operations 160/215 11.1.3 Direct In Direct instructions, the operands are referenced by their memory address. The direct addressing mode consists of two submodes: Direct (short) The address is a byte, thus requires only one byte after the opcode, but only allows 00 - FF addressing space. Direct (long) The address is a word, thus allowing 64 Kbyte addressing space, but requires 2 bytes after the opcode. 11.1.4 Indexed (No Offset, Short, Long) In this mode, the operand is referenced by its memory address, which is defined by the unsigned addition of an index register (X or Y) with an offset. The indirect addressing mode consists of three sub-modes: Indexed (No Offset) There is no offset, (no extra byte after the opcode), and allows 00 - FF addressing space. Indexed (Short) The offset is a byte, thus requires only one byte after the opcode and allows 00 - 1FE addressing space. Indexed (long) The offset is a word, thus allowing 64 Kbyte addressing space and requires 2 bytes after the opcode. 11.1.5 Indirect (Short, Long) The required data byte to do the operation is found by its memory address, located in memory (pointer). The pointer address follows the opcode. The indirect addressing mode consists of two sub-modes: Indirect (short) The pointer address is a byte, the pointer size is a byte, thus allowing 00 - FF addressing space, and requires 1 byte after the opcode. Indirect (long) The pointer address is a byte, the pointer size is a word, thus allowing 64 Kbyte addressing space, and requires 1 byte after the opcode. ST72F521, ST72521B INSTRUCTION SET OVERVIEW (Cont'd) 11.1.6 Indirect Indexed (Short, Long) This is a combination of indirect and short indexed addressing modes. The operand is referenced by its memory address, which is defined by the unsigned addition of an index register value (X or Y) with a pointer value located in memory. The pointer address follows the opcode. The indirect indexed addressing mode consists of two sub-modes: Indirect Indexed (Short) The pointer address is a byte, the pointer size is a byte, thus allowing 00 - 1FE addressing space, and requires 1 byte after the opcode. Indirect Indexed (Long) The pointer address is a byte, the pointer size is a word, thus allowing 64 Kbyte addressing space, and requires 1 byte after the opcode. Table 27. Instructions Supporting Direct, Indexed, Indirect and Indirect Indexed Addressing Modes Long and Short Instructions LD Available Relative Direct/Indirect Instructions Function JRxx Conditional Jump CALLR Call Relative The relative addressing mode consists of two submodes: Relative (Direct) The offset is following the opcode. Relative (Indirect) The offset is defined in memory, which address follows the opcode. Function Load CP Compare AND, OR, XOR Logical Operations ADC, ADD, SUB, SBC Arithmetic Additions/Substractions operations BCP Bit Compare Short Instructions Only CLR 11.1.7 Relative mode (Direct, Indirect) This addressing mode is used to modify the PC register value, by adding an 8-bit signed offset to it. Function Clear INC, DEC Increment/Decrement TNZ Test Negative or Zero CPL, NEG 1 or 2 Complement BSET, BRES Bit Operations BTJT, BTJF Bit Test and Jump Operations SLL, SRL, SRA, RLC, RRC Shift and Rotate Operations SWAP Swap Nibbles CALL, JP Call or Jump subroutine 161/215 ST72F521, ST72521B INSTRUCTION SET OVERVIEW (Cont'd) 11.2 INSTRUCTION GROUPS The ST7 family devices use an Instruction Set consisting of 63 instructions. The instructions may be subdivided into 13 main groups as illustrated in the following table: Load and Transfer LD CLR Stack operation PUSH POP Increment/Decrement INC DEC Compare and Tests CP TNZ BCP Logical operations AND OR XOR CPL NEG Bit Operation BSET BRES Conditional Bit Test and Branch BTJT BTJF Arithmetic operations ADC ADD SUB SBC MUL Shift and Rotates SLL SRL SRA RLC RRC SWAP SLA Unconditional Jump or Call JRA JRT JRF JP CALL CALLR NOP Conditional Branch JRxx Interruption management TRAP WFI HALT IRET Condition Code Flag modification SIM RIM SCF RCF Using a pre-byte The instructions are described with one to four opcodes. In order to extend the number of available opcodes for an 8-bit CPU (256 opcodes), three different prebyte opcodes are defined. These prebytes modify the meaning of the instruction they precede. The whole instruction becomes: PC-2 End of previous instruction PC-1 Prebyte PC opcode PC+1 Additional word (0 to 2) according to the number of bytes required to compute the effective address 162/215 RSP RET These prebytes enable instruction in Y as well as indirect addressing modes to be implemented. They precede the opcode of the instruction in X or the instruction using direct addressing mode. The prebytes are: PDY 90 Replace an X based instruction using immediate, direct, indexed, or inherent addressing mode by a Y one. PIX 92 Replace an instruction using direct, direct bit, or direct relative addressing mode to an instruction using the corresponding indirect addressing mode. It also changes an instruction using X indexed addressing mode to an instruction using indirect X indexed addressing mode. PIY 91 Replace an instruction using X indirect indexed addressing mode by a Y one. ST72F521, ST72521B INSTRUCTION SET OVERVIEW (Cont'd) Mnemo Description Function/Example Dst Src I1 H I0 N Z C ADC Add with Carry A=A+M+C A M H N Z C ADD Addition A=A+M A M H N Z C AND Logical And A=A.M A M N Z BCP Bit compare A, Memory tst (A . M) A M N Z BRES Bit Reset bres Byte, #3 M BSET Bit Set bset Byte, #3 M BTJF Jump if bit is false (0) btjf Byte, #3, Jmp1 M C BTJT Jump if bit is true (1) btjt Byte, #3, Jmp1 M C CALL Call subroutine CALLR Call subroutine relative CLR Clear CP Arithmetic Compare tst(Reg - M) reg CPL One Complement A = FFH-A DEC Decrement dec Y HALT Halt IRET Interrupt routine return Pop CC, A, X, PC INC Increment inc X JP Absolute Jump jp [TBL.w] JRA Jump relative always JRT Jump relative JRF Never jump jrf * JRIH Jump if ext. INT pin = 1 (ext. INT pin high) JRIL Jump if ext. INT pin = 0 (ext. INT pin low) JRH Jump if H = 1 H=1? JRNH Jump if H = 0 H=0? JRM Jump if I1:0 = 11 I1:0 = 11 ? JRNM Jump if I1:0 <> 11 I1:0 <> 11 ? JRMI Jump if N = 1 (minus) N=1? JRPL Jump if N = 0 (plus) N=0? reg, M 0 1 N Z C reg, M N Z 1 reg, M N Z N Z N Z M 1 JREQ Jump if Z = 1 (equal) Z=1? JRNE Jump if Z = 0 (not equal) Z=0? JRC Jump if C = 1 C=1? JRNC Jump if C = 0 C=0? JRULT Jump if C = 1 Unsigned < JRUGE Jump if C = 0 Jmp if unsigned >= JRUGT Jump if (C + Z = 0) Unsigned > I1 reg, M 0 H I0 C 163/215 ST72F521, ST72521B INSTRUCTION SET OVERVIEW (Cont'd) Mnemo Description Dst Src JRULE Jump if (C + Z = 1) Unsigned <= LD Load dst <= src reg, M M, reg MUL Multiply X,A = X * A A, X, Y X, Y, A NEG Negate (2's compl) neg $10 reg, M NOP No Operation OR OR operation A=A+M A M POP Pop from the Stack pop reg reg M pop CC CC M PUSH Push onto the Stack push Y M reg, CC RCF Reset carry flag C=0 RET Subroutine Return RIM Enable Interrupts I1:0 = 10 (level 0) RLC Rotate left true C C <= A <= C reg, M N Z C RRC Rotate right true C C => A => C reg, M N Z C RSP Reset Stack Pointer S = Max allowed SBC Substract with Carry A=A-M-C N Z C SCF Set carry flag C=1 SIM Disable Interrupts I1:0 = 11 (level 3) SLA Shift left Arithmetic C <= A <= 0 reg, M N Z C SLL Shift left Logic C <= A <= 0 reg, M N Z C SRL Shift right Logic 0 => A => C reg, M 0 Z C SRA Shift right Arithmetic A7 => A => C reg, M N Z C SUB Substraction A=A-M A N Z C SWAP SWAP nibbles A7-A4 <=> A3-A0 reg, M N Z TNZ Test for Neg & Zero tnz lbl1 N Z TRAP S/W trap S/W interrupt WFI Wait for Interrupt XOR Exclusive OR N Z 164/215 Function/Example A = A XOR M I1 H I0 N Z N Z 0 I1 H C 0 I0 N Z N Z N Z C C 0 1 A 0 M 1 1 A 1 M M 1 1 1 0 ST72F521, ST72521B 12 ELECTRICAL CHARACTERISTICS 12.1 PARAMETER CONDITIONS Unless otherwise specified, all voltages are referred to VSS. 12.1.1 Minimum and Maximum values Unless otherwise specified the minimum and maximum values are guaranteed in the worst conditions of ambient temperature, supply voltage and frequencies by tests in production on 100% of the devices with an ambient temperature at TA=25C and TA=TAmax (given by the selected temperature range). Data based on characterization results, design simulation and/or technology characteristics are indicated in the table footnotes and are not tested in production. Based on characterization, the minimum and maximum values refer to sample tests and represent the mean value plus or minus three times the standard deviation (mean3). 12.1.2 Typical values Unless otherwise specified, typical data are based on TA=25C, VDD=5V.They are given only as design guidelines and are not tested. 12.1.3 Typical curves Unless otherwise specified, all typical curves are given only as design guidelines and are not tested. 12.1.4 Loading capacitor The loading conditions used for pin parameter measurement are shown in Figure 84. Figure 85. Pin input voltage ST7 PIN VIN Figure 84. Pin loading conditions ST7 PIN CL 12.1.5 Pin input voltage The input voltage measurement on a pin of the device is described in Figure 85. 165/215 ST72F521, ST72521B 12.2 ABSOLUTE MAXIMUM RATINGS Stresses above those listed as "absolute maximum ratings" may cause permanent damage to the device. This is a stress rating only and functional operation of the device under these condi12.2.1 Voltage Characteristics Symbol tions is not implied. Exposure to maximum rating conditions for extended periods may affect device reliability. Ratings Maximum value VDD - VSS Supply voltage 6.5 VPP - VSS Programming Voltage 13 VIN 1) & 2) Input Voltage on true open drain pin VSS-0.3 to 6.5 |VSSA - VSSx| V VSS-0.3 to VDD+0.3 Input voltage on any other pin |VDDx| and |VSSx| Unit Variations between different digital power pins 50 Variations between digital and analog ground pins 50 VESD(HBM) Electro-static discharge voltage (Human Body Model) VESD(MM) Electro-static discharge voltage (Machine Model) mV see section 12.7.3 on page 181 12.2.2 Current Characteristics Symbol Ratings Maximum value IVDD Total current into VDD power lines (source) 3) 150 IVSS Total current out of VSS ground lines (sink) 3) 150 IIO Output current sunk by any standard I/O and control pin 25 Output current sunk by any high sink I/O pin 50 Output current source by any I/Os and control pin IINJ(PIN) 2) & 4) 5 Injected current on RESET pin 5 Injected current on OSC1 and OSC2 pins 5 Injected current on PC6 (Flash devices only) +5 Injected current on any other pin IINJ(PIN) 2) Total injected current (sum of all I/O and control mA - 25 Injected current on VPP pin 5) & 6) Unit mA 5 pins) 5) 25 Notes: 1. Directly connecting the RESET and I/O pins to VDD or VSS could damage the device if an unintentional internal reset is generated or an unexpected change of the I/O configuration occurs (for example, due to a corrupted program counter). To guarantee safe operation, this connection has to be done through a pull-up or pull-down resistor (typical: 4.7k for RESET, 10k for I/Os). For the same reason, unused I/O pins must not be directly tied to VDD or VSS. 2. IINJ(PIN) must never be exceeded. This is implicitly insured if VIN maximum is respected. If VIN maximum cannot be respected, the injection current must be limited externally to the IINJ(PIN) value. A positive injection is induced by VIN>VDD while a negative injection is induced by VIN<VSS. For true open-drain pads, there is no positive injection current, and the corresponding VIN maximum must always be respected 3. All power (VDD) and ground (VSS) lines must always be connected to the external supply. 4. Negative injection disturbs the analog performance of the device. See note in "ADC Accuracy" on page 196. For best reliability, it is recommended to avoid negative injection of more than 1.6mA. 5. When several inputs are submitted to a current injection, the maximum IINJ(PIN) is the absolute sum of the positive and negative injected currents (instantaneous values). These results are based on characterisation with IINJ(PIN) maximum current injection on four I/O port pins of the device. 6. True open drain I/O port pins do not accept positive injection. 166/215 ST72F521, ST72521B 12.2.3 Thermal Characteristics Symbol TSTG TJ Ratings Storage temperature range Value Unit -65 to +150 C Maximum junction temperature (see Section 13.2 THERMAL CHARACTERISTICS) 12.3 OPERATING CONDITIONS 12.3.1 General Operating Conditions Symbol Parameter Conditions fCPU Internal clock frequency VDD Standard voltage range (except Flash Write/Erase) Operating Voltage for Flash Write/Erase TA Ambient temperature range Min Max Unit 0 8 MHz 3.8 5.5 4.5 5.5 1 Suffix Version 0 70 5 Suffix Version -10 85 6 or A Suffix Versions -40 85 7 or B Suffix Versions -40 105 C Suffix Version -40 125 VPP = 11.4 to 12.6V V C Figure 86. fCPU Max Versus VDD fCPU [MHz] FUNCTIONALITY GUARANTEED IN THIS AREA (UNLESS OTHERWISE SPECIFIED IN THE TABLES OF PARAMETRIC DATA) 8 FUNCTIONALITY NOT GUARANTEED IN THIS AREA 6 4 2 1 0 3.5 3.8 4.0 4.5 5.5 SUPPLY VOLTAGE [V] Note: Some temperature ranges are only available with a specific package and memory size. Refer to Ordering Information. 167/215 ST72F521, ST72521B OPERATING CONDITIONS (Cont'd) 12.3.2 Operating Conditions with Low Voltage Detector (LVD) Subject to general operating conditions for VDD, fCPU, and TA. Symbol Parameter VIT+(LVD) Reset release threshold (VDD rise) VIT-(LVD) Reset generation threshold (VDD fall) Vhys(LVD) 1) VtPOR VDD rise time 1)2) tg(VDD) VDD glitches filtered (not detected) by LVD 1) LVD voltage threshold hysteresis Conditions Min Typ Max VD level = High in option byte 4.0 1) 4.2 4.5 VD level = Med. in option byte3) 3.55 1) VD level = Low in option byte3) 2.95 1) 3.75 3.15 4.01) 3.351) VD level = High in option byte 4.0 4.25 1) VD level = Med. in option byte3) 3.351) VD level = Low in option byte3) 2.81) 3.55 3.0 3.751) 3.15 1) VIT+(LVD)-VIT-(LVD) 200 250 3.8 150 Flash device, LVD enabled 6s/V 20ms/V ROM device, LVD enabled 6s/V 100ms/V 40 Unit V mV ns Notes: 1. Data based on characterization results, tested in production for ROM devices only. 2. When VtPOR is faster than 100 s/V, the Reset signal is released after a delay of max. 42s after VDD crosses the VIT+(LVD) threshold. 3. If the medium or low thresholds are selected, the detection may occur outside the specified operating voltage range. Below 3.8V, device operation is not guaranteed. 12.3.3 Auxiliary Voltage Detector (AVD) Thresholds Subject to general operating conditions for VDD, fCPU, and TA. Symbol VIT+(AVD) Parameter 10 AVDF flag toggle threshold (VDD rise) Conditions Min 1) Typ Max VD level = High in option byte 4.4 4.6 4.9 VD level = Med. in option byte VD level = Low in option byte 3.95 1) 3.4 1) 4.15 3.6 4.41) 3.81) VD level = High in option byte 4.2 4.4 4.65 1) VD level = Med. in option byte VD level = Low in option byte 3.751) 3.21) 4.0 3.4 4.2 1) 3.6 1) Unit V VIT-(AVD) 01 AVDF flag toggle threshold (VDD fall) Vhys(AVD) AVD voltage threshold hysteresis VIT+(AVD)-VIT-(AVD) 200 mV VIT- Voltage drop between AVD flag set and LVD reset activated VIT-(AVD)-VIT-(LVD) 450 mV 1. Data based on characterization results, tested in production for ROM devices only. 12.3.4 External Voltage Detector (EVD) Thresholds Subject to general operating conditions for VDD, fCPU, and TA. Symbol Min Typ Max VIT+(EVD) 10 AVDF flag toggle threshold (VDD rise)1) Parameter Conditions 1.15 1.26 1.35 VIT-(EVD) 01 AVDF flag toggle threshold (VDD fall)1) 1.1 1.2 1.3 Vhys(EVD) EVD voltage threshold hysteresis V VIT+(EVD)-VIT-(EVD) 1. Data based on characterization results, not tested in production. 168/215 Unit 200 mV ST72F521, ST72521B 12.4 SUPPLY CURRENT CHARACTERISTICS The following current consumption specified for the ST7 functional operating modes over temperature range does not take into account the clock source current consumption. To get the total device consumption, the two current values must be added (except for HALT mode for which the clock is stopped). 12.4.1 CURRENT CONSUMPTION Symbol IDD Parameter Conditions Max 1) Typ Max 1) 1.3 2.0 3.6 7.1 3.0 5.0 8.0 15.0 1.3 2.0 3.6 7.1 2.0 3.0 5.0 10.0 mA 600 700 800 1100 2700 3000 3600 4000 600 700 800 1100 1800 2100 2400 3000 A 1.0 1.5 2.5 4.5 3.0 4.0 5.0 7.0 1.0 1.5 2.5 4.5 1.3 2.0 3.3 6.0 mA 580 650 770 1050 1200 1300 1800 2000 70 100 200 350 200 300 600 1200 A -40CTA+85C <1 10 <1 10 -40CTA+125C <1 50 <1 50 80 160 325 650 No max. guaranteed 15 30 60 120 25 50 100 200 fOSC=2MHz, fCPU=1MHz fOSC=4MHz, fCPU=2MHz fOSC=8MHz, fCPU=4MHz fOSC=16MHz, fCPU=8MHz Supply current in SLOW mode 2) fOSC=2MHz, fCPU=62.5kHz fOSC=4MHz, fCPU=125kHz fOSC=8MHz, fCPU=250kHz fOSC=16MHz, fCPU=500kHz Supply current in WAIT mode fOSC=2MHz, fCPU=1MHz fOSC=4MHz, fCPU=2MHz fOSC=8MHz, fCPU=4MHz fOSC=16MHz, fCPU=8MHz fOSC=2MHz, fCPU=62.5kHz =4MHz, fCPU=125kHz f Supply current in SLOW WAIT mode 2) OSC fOSC=8MHz, fCPU=250kHz fOSC=16MHz, fCPU=500kHz Supply current in HALT mode 3) IDD Unit Typ Supply current in RUN mode 2) 2) Flash Devices ROM Devices fOSC=2MHz Supply current in ACTIVE-HALT mode fOSC=4MHz 4) fOSC=8MHz fOSC =16MHz A A Notes: 1. Data based on characterization results, tested in production at VDD max. and fCPU max. 2. Measurements are done in the following conditions: - Program executed from RAM, CPU running with RAM access. The increase in consumption when executing from Flash is 50%. - All I/O pins in input mode with a static value at VDD or VSS (no load) - All peripherals in reset state. - LVD disabled. - Clock input (OSC1) driven by external square wave. - In SLOW and SLOW WAIT mode, fCPU is based on fOSC divided by 32. To obtain the total current consumption of the device, add the clock source (Section 12.4.2) and the peripheral power consumption (Section 12.4.3). 3. All I/O pins in push-pull 0 mode (when applicable) with a static value at VDD or VSS (no load), LVD disabled. Data based on characterization results, tested in production at VDD max. and fCPU max. 4. Data based on characterisation results, not tested in production. All I/O pins in push-pull 0 mode (when applicable) with a static value at VDD or VSS (no load); clock input (OSC1) driven by external square wave, LVD disabled. To obtain the total current consumption of the device, add the clock source consumption (Section 12.4.2). 169/215 ST72F521, ST72521B SUPPLY CURRENT CHARACTERISTICS (Cont'd) 12.4.1.1 Power Consumption vs fCPU: Flash Devices Figure 87. Typical IDD in RUN mode Figure 89. Typical IDD in WAIT mode 8 7 5 4 Idd (mA) 6 Idd (mA) 8MHz 4MHz 2MHz 1MHz 6 8MHz 4MHz 2MHz 1MHz 9 5 4 3 2 3 2 1 1 0 0 3.2 3.6 4 4.4 4.8 5.2 3.2 5.5 3.6 4 5.5 500kHz 1.20 500kHz 250kHz 1.00 125kHz 62.5kHz 0.80 250kHz 125kHz 62.5kHz ) ( 0.80 Idd (mA) 5.2 Figure 90. Typ. IDD in SLOW-WAIT mode Figure 88. Typical IDD in SLOW mode 1.00 4.8 Vdd (V) Vdd (V) 1.20 4.4 0.60 0.60 0.40 0.40 0.20 0.20 0.00 3.2 0.00 3.2 3.6 4 4.4 Vdd (V) 170/215 4.8 5.2 5.5 3.6 4 4.4 Vdd (V) 4.8 5.2 5.5 ST72F521, ST72521B SUPPLY CURRENT CHARACTERISTICS (Cont'd) 12.4.2 Supply and Clock Managers The previous current consumption specified for the ST7 functional operating modes over temperature range does not take into account the clock source current consumption. To get the total device consumption, the two current values must be added (except for HALT mode). Symbol Parameter Conditions IDD(RCINT) Supply current of internal RC oscillator Typ Max Unit 625 see section 12.5.3 on page 174 IDD(RES) Supply current of resonator oscillator 1) & 2) IDD(PLL) PLL supply current VDD= 5V 360 IDD(LVD) LVD supply current VDD= 5V 150 A 300 Notes: 1.. Data based on characterization results done with the external components specified in Section 12.5.3, not tested in production. 2. As the oscillator is based on a current source, the consumption does not depend on the voltage. 171/215 ST72F521, ST72521B SUPPLY CURRENT CHARACTERISTICS (Cont'd) 12.4.3 On-Chip Peripherals Measured on S72F521R9T3 on TQFP64 generic board TA = 25C fCPU=4MHz. Symbol Typ Unit IDD(TIM) 16-bit Timer supply current 1) VDD=5.0V 50 A IDD(ART) ART PWM supply current2) VDD=5.0V 75 A IDD(SPI) SPI supply current 3) VDD=5.0V 400 A IDD(SCI) SCI supply current 4) VDD=5.0V 400 A IDD(I2C) I2C supply current 5) VDD=5.0V 175 A IDD(ADC) ADC supply current when converting 6) VDD=5.0V 400 A VDD=5.0V 400 A IDD(CAN) Parameter CAN supply current 5) Conditions Notes: 1. Data based on a differential IDD measurement between reset configuration (timer counter running at fCPU/4) and timer counter stopped (only TIMD bit set). Data valid for one timer. 2. Data based on a differential IDD measurement between reset configuration (timer stopped) and timer counter enabled (only TCE bit set). 3. Data based on a differential IDD measurement between reset configuration (SPI disabled) and a permanent SPI master communication at maximum speed (data sent equal to 55h).This measurement includes the pad toggling consumption. 4. Data based on a differential IDD measurement between SCI low power state (SCID=1) and a permanent SCI data transmit sequence. 5. Data based on a differential IDD measurement between reset configuration (I2C disabled) and a permanent I2C master communication at 100kHz (data sent equal to 55h). This measurement include the pad toggling consumption (27kOhm external pull-up on clock and data lines). 6. Data based on a differential IDD measurement between reset configuration and continuous A/D conversions. 7. Data based on a differential IDD measurement between reset configuration (CAN disabled) and a permanent CAN data transmit sequence with RX and TX connected together. This measurement include the pad toggling consumption. 172/215 ST72F521, ST72521B 12.5 CLOCK AND TIMING CHARACTERISTICS Subject to general operating conditions for VDD, fCPU, and TA. 12.5.1 General Timings Symbol tc(INST) tv(IT) Parameter Conditions Instruction cycle time Interrupt reaction time tv(IT) = tc(INST) + 10 fCPU=8MHz 2) fCPU=8MHz Min Typ 1) Max Unit 2 3 12 tCPU 250 375 1500 ns 10 22 tCPU 1.25 2.75 s Max Unit 12.5.2 External Clock Source Symbol Parameter Conditions Min Typ VOSC1H OSC1 input pin high level voltage VDD-1 VDD VOSC1L OSC1 input pin low level voltage VSS VSS+1 tw(OSC1H) tw(OSC1L) OSC1 high or low time 3) tr(OSC1) tf(OSC1) OSC1 rise or fall time 3) IL see Figure 91 V 5 ns 15 VSSVINVDD OSC1 Input leakage current 1 A Figure 91. Typical Application with an External Clock Source 90% VOSC1H 10% VOSC1L tr(OSC1) tf(OSC1) OSC2 tw(OSC1H) tw(OSC1L) Not connected internally fOSC EXTERNAL CLOCK SOURCE OSC1 IL ST72XXX Notes: 1. Data based on typical application software. 2. Time measured between interrupt event and interrupt vector fetch. tc(INST) is the number of tCPU cycles needed to finish the current instruction execution. 3. Data based on design simulation and/or technology characteristics, not tested in production. 173/215 ST72F521, ST72521B CLOCK AND TIMING CHARACTERISTICS (Cont'd) 12.5.3 Crystal and Ceramic Resonator Oscillators The ST7 internal clock can be supplied with four different Crystal/Ceramic resonator oscillators. All the information given in this paragraph are based on characterization results with specified typical external components. In the application, the resonator and the load capacitors have to be placed as Symbol Parameter fOSC Oscillator Frequency 1) RF Feedback resistor2) CL1 CL2 Recommended load capacitance versus equivalent serial resistance of the crystal or ceramic resonator (RS) Symbol Min Max Unit LP: Low power oscillator MP: Medium power oscillator MS: Medium speed oscillator HS: High speed oscillator Conditions 1 >2 >4 >8 2 4 8 16 MHz 20 40 k RS=200 RS=200 RS=200 RS=100 22 22 18 15 56 46 33 33 pF Typ Max Unit 80 160 310 610 150 250 460 910 A Parameter LP oscillator MP oscillator MS oscillator HS oscillator Conditions VDD=5V VIN=VSS OSC2 driving current i2 close as possible to the oscillator pins in order to minimize output distortion and start-up stabilization time. Refer to the crystal/ceramic resonator manufacturer for more details (frequency, package, accuracy...). LP oscillator MP oscillator MS oscillator HS oscillator Figure 92. Typical Application with a Crystal or Ceramic Resonator WHEN RESONATOR WITH INTEGRATED CAPACITORS i2 fOSC CL1 OSC1 RESONATOR CL2 RF OSC2 ST72XXX Notes: 1. The oscillator selection can be optimized in terms of supply current using an high quality resonator with small RS value. Refer to crystal/ceramic resonator manufacturer for more details. 2. Data based on characterisation results, not tested in production. 174/215 ST72F521, ST72521B CLOCK AND TIMING CHARACTERISTICS (Cont'd) Murata Supplier fOSC Typical Ceramic Resonators (MHz) Reference2) Recommended OSCRANGE Option bit configuration 2 CSTCC2M00G56A-R0 MP Mode3) 4 CSTCR4M00G55B-R0 MS Mode 8 CSTCE8M00G55A-R0 HS Mode 16 CSTCE16M0G53A-R0 HS Mode Notes: 1. Resonator characteristics given by the ceramic resonator manufacturer. 2. SMD = [-R0: Plastic tape package ( =180mm), -B0: Bulk] LEAD = [-A0: Flat pack package (Radial taping Ho= 18mm), -B0: Bulk] 3. LP mode is not recommended for 2 MHz resonator because the peak to peak amplitude is too small (>0.8V) For more information on these resonators, please consult www.murata.com 175/215 ST72F521, ST72521B CLOCK CHARACTERISTICS (Cont'd) 12.5.4 RC Oscillators Symbol fOSC (RCINT) Parameter Conditions Internal RC oscillator frequency TA=25C, VDD=5V See Figure 93 Figure 93. Typical fOSC(RCINT) vs TA fOSC(RCINT) (MHz) Vdd = 5V Vdd = 5.5V 3.6 3.4 3.2 3 -45 0 25 TA(C) 176/215 70 Typ Max Unit 2 3.5 5.6 MHz Note: To reduce disturbance to the RC oscillator, it is recommended to place decoupling capacitors between VDD and VSS as shown in Figure 113 4 3.8 Min 130 ST72F521, ST72521B CLOCK CHARACTERISTICS (Cont'd) 12.5.5 PLL Characteristics Symbol Parameter fOSC Conditions PLL input frequency range Instantaneous PLL jitter 1) fCPU/ fCPU Min Typ 2 Max Unit 4 MHz ROM device, fOSC = 4 MHz. 0.7 2 Flash device, fOSC = 4 MHz. 1.0 2.5 Flash device, fOSC = 2 MHz. 2.5 4.0 % Note: 1. Data characterized but not tested. The user must take the PLL jitter into account in the application (for example in serial communication or sampling of high frequency signals). The PLL jitter is a periodic effect, which is integrated over several CPU cycles. Therefore the longer the period of the application signal, the less it will be impacted by the PLL jitter. Figure 94 shows the PLL jitter integrated on application signals in the range 125kHz to 4MHz. At frequencies of less than 125KHz, the jitter is negligible. Figure 94. Integrated PLL Jitter vs signal frequency1 +/-Jitter (%) 1.2 FLASH typ 1 ROM max ROM typ 0.8 0.6 0.4 0.2 0 4 MHz 2 MHz 1 MHz 500 kHz 250 kHz 125 kHz Application Frequency Note 1: Measurement conditions: fCPU = 8MHz. 177/215 ST72F521, ST72521B 12.6 MEMORY CHARACTERISTICS 12.6.1 RAM and Hardware Registers Symbol VRM Parameter Data retention mode 1) Conditions HALT mode (or RESET) Min Typ Max 1.6 Unit V 12.6.2 FLASH Memory DUAL VOLTAGE HDFLASH MEMORY Symbol Parameter fCPU Operating frequency VPP Programming voltage 3) IDD Supply current4) IPP tVPP tRET NRW TPROG TERASE VPP current4) Internal VPP stabilization time Data retention Write erase cycles Programming or erasing temperature range Conditions Read mode Write / Erase mode 4.5V VDD 5.5V RUN mode (fCPU = 4MHz) Write / Erase Power down mode / HALT Read (VPP=12V) Write / Erase Min 2) 0 1 11.4 Typ 0 1 Max 2) 8 8 12.6 3 10 200 30 10 TA=55C TA=25C 20 100 -40 25 85 Unit MHz V mA A mA s years cycles C Notes: 1. Minimum VDD supply voltage without losing data stored in RAM (in HALT mode or under RESET) or in hardware registers (only in HALT mode). Not tested in production. 2. Data based on characterization results, not tested in production. 3. VPP must be applied only during the programming or erasing operation and not permanently for reliability reasons. 4. Data based on simulation results, not tested in production. Warning: Do not connect 12V to VPP before VDD is powered on, as this may damage the device. 178/215 ST72F521, ST72521B 12.7 EMC CHARACTERISTICS Susceptibility tests are performed on a sample basis during product characterization. 12.7.1 Functional EMS (Electro Magnetic Susceptibility) Based on a simple running application on the product (toggling 2 LEDs through I/O ports), the product is stressed by two electro magnetic events until a failure occurs (indicated by the LEDs). ESD: Electro-Static Discharge (positive and negative) is applied on all pins of the device until a functional disturbance occurs. This test conforms with the IEC 1000-4-2 standard. FTB: A Burst of Fast Transient voltage (positive and negative) is applied to VDD and VSS through a 100pF capacitor, until a functional disturbance occurs. This test conforms with the IEC 1000-44 standard. A device reset allows normal operations to be resumed. The test results are given in the table below based on the EMS levels and classes defined in application note AN1709. 12.7.1.1 Designing hardened software to avoid noise problems EMC characterization and optimization are performed at component level with a typical application environment and simplified MCU software. It Symbol VFESD Parameter should be noted that good EMC performance is highly dependent on the user application and the software in particular. Therefore it is recommended that the user applies EMC software optimization and prequalification tests in relation with the EMC level requested for his application. Software recommendations: The software flowchart must include the management of runaway conditions such as: - Corrupted program counter - Unexpected reset - Critical Data corruption (control registers...) Prequalification trials: Most of the common failures (unexpected reset and program counter corruption) can be reproduced by manually forcing a low state on the RESET pin or the Oscillator pins for 1 second. To complete these trials, ESD stress can be applied directly on the device, over the range of specification values. When unexpected behaviour is detected, the software can be hardened to prevent unrecoverable errors occurring (see application note AN1015) . Conditions Flash device: VDD=5V, TA=+25C, Voltage limits to be applied on any I/O pin to induce a fOSC=8MHz, conforms to IEC 1000-4-2 functional disturbance ROM device: VDD=5V, TA=+25C, fOSC=8MHz,conforms to IEC 1000-4-2 Level/ Class 4B 3B VFFTB Fast transient voltage burst limits to be applied Flash device: VDD=5V, TA=+25C, fOSC=8 through 100pF on VDD and VDD pins to induce a funcMHz, conforms to IEC 1000-4-4 tional disturbance 3B VFFTB Fast transient voltage burst limits to be applied Flash device: VDD=5V, TA=+25C, fOSC=8 through 100pF on VDD and VDD pins to induce a funcMHz, conforms to IEC 1000-4-4 tional disturbance 3B 179/215 ST72F521, ST72521B EMC CHARACTERISTICS (Cont'd) 12.7.2 Electro Magnetic Interference (EMI) Based on a simple application running on the product (toggling 2 LEDs through the I/O ports), the product is monitored in terms of emission. This emission test is in line with the norm SAE J 1752/ 3 which specifies the board and the loading of each pin. Symbol SEMI Parameter Peak level Conditions Monitored Frequency Band 0.1MHz to 30MHz VDD=5V, TA=+25C, 30MHz to 130MHz TQFP64 14x14 package conforming to SAE J 1752/3 130MHz to 1GHz SAE EMI Level Notes: 1. Data based on characterization results, not tested in production. 2. Refer to Application Note AN1709 for data on other package types. 180/215 Max vs. [fOSC/fCPU] 8/4MHz 16/8MHz 15 15 20 27 0 5 2.5 3.0 Unit dBV - ST72F521, ST72521B EMC CHARACTERISTICS (Cont'd) 12.7.3 Absolute Maximum Ratings (Electrical Sensitivity) Based on three different tests (ESD, LU and DLU) using specific measurement methods, the product is stressed in order to determine its performance in terms of electrical sensitivity. For more details, refer to the application note AN1181. 12.7.3.1 Electro-Static Discharge (ESD) Electro-Static Discharges (a positive then a negative pulse separated by 1 second) are applied to the pins of each sample according to each pin combination. The sample size depends on the number of supply pins in the device (3 parts*(n+1) supply pin). Two models can be simulated: Human Body Model and Machine Model. This test conforms to the JESD22-A114A/A115A standard. Absolute Maximum Ratings Symbol Ratings Conditions Maximum value 1) Unit VESD(HBM) Electro-static discharge voltage (Human Body Model) TA=+25C 2000 VESD(MM) Electro-static discharge voltage (Machine Model) TA=+25C 200 V Notes: 1. Data based on characterization results, not tested in production. 12.7.3.2 Static and Dynamic Latch-Up LU: 3 complementary static tests are required on 10 parts to assess the latch-up performance. A supply overvoltage (applied to each power supply pin) and a current injection (applied to each input, output and configurable I/O pin) are performed on each sample. This test conforms to the EIA/JESD 78 IC latch-up standard. For more details, refer to the application note AN1181. DLU: Electro-Static Discharges (one positive then one negative test) are applied to each pin of 3 samples when the micro is running to assess the latch-up performance in dynamic mode. Power supplies are set to the typical values, the oscillator is connected as near as possible to the pins of the micro and the component is put in reset mode. This test conforms to the IEC1000-4-2 and SAEJ1752/3 standards. For more details, refer to the application note AN1181. Electrical Sensitivities Symbol LU DLU Parameter Conditions Class 1) Static latch-up class TA=+25C TA=+85C TA=+125C A A A Dynamic latch-up class VDD=5.5V, fOSC=4MHz, TA=+25C A Notes: 1. Class description: A Class is an STMicroelectronics internal specification. All its limits are higher than the JEDEC specifications, that means when a device belongs to Class A it exceeds the JEDEC standard. B Class strictly covers all the JEDEC criteria (international standard). 181/215 ST72F521, ST72521B 12.8 I/O PORT PIN CHARACTERISTICS 12.8.1 General Characteristics Subject to general operating conditions for VDD, fOSC, and TA unless otherwise specified. Symbol Parameter Conditions VIL Input low level voltage VIH Input high level voltage 1) Vhys Schmitt trigger voltage hysteresis 2) VIL Input low level voltage 1) VIH Input high level voltage 1) Vhys Schmitt trigger voltage hysteresis 2) IINJ(PIN) Min Unit 0.7xVDD 0.7 V 0.8 TTL ports Injected Current on an I/O pin 2 1 0 +4 4 VDD=5V Total injected current (sum of all I/O and control pins) mA 25 IL Input leakage current VSSVINVDD IS Static current consumption Floating input mode4) RPU Weak pull-up equivalent resistor 5) VIN=VSS CIO I/O pin capacitance 5 Output high to low level fall time 1) 25 tf(IO)out Max 0.3xVDD CMOS ports Injected Current on PC6 (Flash de3) vices only) IINJ(PIN)3) Typ 1) 1 VDD=5V 50 tr(IO)out CL=50pF Output low to high level rise time 1) Between 10% and 90% tw(IT)in External interrupt pulse time 6) Figure 95. Unused I/O Pins configured as input A 400 120 250 k pF ns 25 1 tCPU Figure 96. Typical IPU vs. VDD with VIN=VSS 90 VDD ST7XXX Ta=140C 80 Ta=95C 10k 70 Ta=25C UNUSED I/O PORT Ta=-45C UNUSED I/O PORT 10k Ipu(uA ) 60 50 40 30 ST7XXX Note: I/O can be left unconnected if it is configured as output (0 or 1) by the software. This has the advantage of greater EMC robustness and lower cost. 20 10 0 2 2.5 3 3.5 4 4.5 V dd(V) 5 5.5 6 Notes: 1. Data based on characterization results, not tested in production. 2. Hysteresis voltage between Schmitt trigger switching levels. Based on characterization results, not tested. 3. When the current limitation is not possible, the VIN maximum must be respected, otherwise refer to IINJ(PIN) specification. A positive injection is induced by VIN>VDD while a negative injection is induced by VIN<VSS. Refer to section 12.2.2 on page 166 for more details. 4. Configuration not recommended, all unused pins must be kept at a fixed voltage: using the output mode of the I/O for example and leaving the I/O unconnected on the board or an external pull-up or pull-down resistor (see Figure 95). Data based on design simulation and/or technology characteristics, not tested in production. 5. The RPU pull-up equivalent resistor is based on a resistive transistor (corresponding IPU current characteristics described in Figure 96). 6. To generate an external interrupt, a minimum pulse width has to be applied on an I/O port pin configured as an external interrupt source. 182/215 ST72F521, ST72521B I/O PORT PIN CHARACTERISTICS (Cont'd) 12.8.2 Output Driving Current Subject to general operating conditions for VDD, fCPU, and TA unless otherwise specified. Symbol Parameter Conditions VOL 1) Output low level voltage for a high sink I/O pin when 4 pins are sunk at same time (see Figure 98 and Figure 100) VDD=5V Output low level voltage for a standard I/O pin when 8 pins are sunk at same time (see Figure 97) Figure 97. Typical VOL at VDD=5V (standard) Max IIO=+5mA 1.2 IIO=+2mA 0.5 IIO=+20mA, TA85C TA85C 1.3 1.5 IIO=+8mA 0.6 Unit V IIO=-5mA, TA85C VDD-1.4 TA85C VDD-1.6 VDD-0.7 IIO=-2mA Output high level voltage for an I/O pin when 4 pins are sourced at same time (see Figure 99 and Figure 102) VOH 2) Min Figure 99. Typical VOH at VDD=5V 1.4 5.5 1.2 V dd-Voh (V) at Vdd=5V V ol (V ) at Vdd=5V 5 1 0.8 0.6 Ta =14 0C " 0.4 Ta =95 C Ta =25 C 0.2 4.5 4 3.5 V dd= 5V 1 40C m in 3 V dd= 5v 95C m in V dd= 5v 25C m in Ta =-45 C 2.5 V dd= 5v -4 5C m in 0 0 0.005 0.01 0.015 2 -0.01 Iio(A) -0.008 -0.006 -0.004 -0.002 0 Figure 98. Typical VOL at VDD=5V (high-sink) 1 0.9 V ol(V ) at Vdd=5V 0.8 0.7 0.6 0.5 0.4 Ta= 140 C 0.3 Ta= 95 C 0.2 Ta= 25 C 0.1 Ta= -45C 0 0 0.01 0.02 0.03 Iio(A) Notes: 1. The IIO current sunk must always respect the absolute maximum rating specified in Section 12.2.2 and the sum of IIO (I/O ports and control pins) must not exceed IVSS. 2. The IIO current sourced must always respect the absolute maximum rating specified in Section 12.2.2 and the sum of IIO (I/O ports and control pins) must not exceed IVDD. True open drain I/O pins do not have VOH. 183/215 ST72F521, ST72521B I/O PORT PIN CHARACTERISTICS (Cont'd) Figure 100. Typical VOL vs. VDD (standard) 1 0.45 Ta= -4 5C 0.9 0.8 Ta=2 5C Ta= 95C Ta=9 5C 0.35 Ta= 140 C 0.7 Ta=1 40C Vol(V) at Iio=2mA V ol(V ) at Iio=5m A Ta=-4 5C 0.4 Ta= 25C 0.6 0.5 0.4 0.3 0.3 0.25 0.2 0.15 0.2 0.1 0.1 0.05 0 2 2.5 3 3.5 4 4.5 5 5.5 0 6 2 Vdd(V ) 2.5 3 3.5 4 4.5 5 5.5 6 Vdd(V) Figure 101. Typical VOL vs. VDD (high-sink) 1 .6 0 .6 Ta = 140 C 1 .4 0 .5 Ta =95 C 1 .2 Ta =25 C Ta =-45C Vol(V ) at Iio=20m A Vol(V ) at Iio=8m A 0 .4 0 .3 0 .2 1 0 .8 0 .6 Ta= 14 0C 0 .4 Ta=9 5C 0 .1 Ta=2 5C 0 .2 Ta=-45 C 0 0 2 2.5 3 3.5 4 4.5 5 5.5 2 6 2.5 3 3.5 4 4.5 5 5.5 6 V dd(V ) V dd (V ) Figure 102. Typical VDD-VOH vs. VDD 5.5 6 Ta= -4 5C 5 Vdd-Voh(V) at Iio=-5mA Vdd-Voh(V) at Iio=-2m A 5 4.5 4 3.5 Ta= -4 5C 3 Ta= 25C Ta= 25C Ta= 95C Ta= 140C 4 3 2 Ta= 95C 2.5 1 Ta= 140C 2 0 2 2.5 3 3.5 4 Vdd(V) 184/215 4.5 5 5.5 6 2 2.5 3 3.5 4 Vdd(V) 4.5 5 5.5 6 ST72F521, ST72521B 12.9 CONTROL PIN CHARACTERISTICS 12.9.1 Asynchronous RESET Pin Subject to general operating conditions for VDD, fCPU, and TA unless otherwise specified. Symbol Parameter Conditions VIL Input low level voltage VIH Input high level voltage 1) Vhys Schmitt trigger voltage hysteresis 2) VOL Output low level voltage 3) IIO RON Min Typ 1) 0.16xVDD 0.85xVDD 2.5 VDD=5V IIO=+2mA 0.2 Input current on RESET pin tw(RSTL)out Generated reset pulse duration External reset pulse hold time tg(RSTL)in Filtered glitch duration 5) 0.5 2 Weak pull-up equivalent resistor th(RSTL)in Max 4) 20 Stretch applied on external pulse 0 Internal reset sources 20 30 30 Unit V V mA 120 k 426) s 426) s s 2.5 200 ns Notes: 1. Data based on characterization results, not tested in production. 2. Hysteresis voltage between Schmitt trigger switching levels. 3. The IIO current sunk must always respect the absolute maximum rating specified in Section 12.2.2 and the sum of IIO (I/O ports and control pins) must not exceed IVSS. 4. To guarantee the reset of the device, a minimum pulse has to be applied to the RESET pin. All short pulses applied on the RESET pin with a duration below th(RSTL)in can be ignored. 5. The reset network (the resistor and two capacitors) protects the device against parasitic resets, especially in noisy environments. 6. Data guaranteed by design, not tested in production. 185/215 ST72F521, ST72521B CONTROL PIN CHARACTERISTICS (Cont'd) Figure 103. RESET pin protection when LVD is enabled.1)2)3)4) VDD Required Optional (note 3) ST72XXX RON EXTERNAL RESET INTERNAL RESET Filter 0.01F 1M PULSE GENERATOR WATCHDOG LVD RESET Figure 104. RESET pin protection when LVD is disabled.1) Recommended for EMC VDD USER EXTERNAL RESET CIRCUIT VDD ST72XXX VDD 0.01F 4.7k RON INTERNAL RESET Filter 0.01F PULSE GENERATOR WATCHDOG Required Note 1: - The reset network protects the device against parasitic resets. - The output of the external reset circuit must have an open-drain output to drive the ST7 reset pad. Otherwise the device can be damaged when the ST7 generates an internal reset (LVD or watchdog). - Whatever the reset source is (internal or external), the user must ensure that the level on the RESET pin can go below the VIL max. level specified in section 12.9.1 on page 185. Otherwise the reset will not be taken into account internally. - Because the reset circuit is designed to allow the internal RESET to be output in the RESET pin, the user must ensure that the current sunk on the RESET pin is less than the absolute maximum value specified for IINJ(RESET) in section 12.2.2 on page 166. Note 2: When the LVD is enabled, it is recommended not to connect a pull-up resistor or capacitor. A 10nF pull-down capacitor is required to filter noise on the reset line. Note 3: In case a capacitive power supply is used, it is recommended to connect a 1M pull-down resistor to the RESET pin to discharge any residual voltage induced by the capacitive effect of the power supply (this will add 5A to the power consumption of the MCU). Note 4: Tips when using the LVD: - 1. Check that all recommendations related to reset circuit have been applied (see notes above). - 2. Check that the power supply is properly decoupled (100nF + 10F close to the MCU). Refer to AN1709 and AN2017. If this cannot be done, it is recommended to put a 100nF + 1M pull-down on the RESET pin. - 3. The capacitors connected on the RESET pin and also the power supply are key to avoid any start-up marginality. In most cases, steps 1 and 2 above are sufficient for a robust solution. Otherwise: replace 10nF pull-down on the RESET pin with a 5F to 20F capacitor. 186/215 ST72F521, ST72521B CONTROL PIN CHARACTERISTICS (Cont'd) 12.9.2 ICCSEL/VPP Pin Subject to general operating conditions for VDD, fCPU, and TA unless otherwise specified. Symbol Parameter Conditions Min Max VSS 0.2 ROM versions VSS 0.3xVDD VIL Input low level voltage 1) FLASH versions VIH Input high level voltage 1) FLASH versions VDD-0.1 12.6 ROM versions 0.7xVDD VDD IL Input leakage current VIN=VSS 1 Unit V A Figure 105. Two typical Applications with ICCSEL/VPP Pin 2) ICCSEL/VPP ST72XXX VPP PROGRAMMING TOOL 10k ST72XXX Notes: 1. Data based on design simulation and/or technology characteristics, not tested in production. 2. When ICC mode is not required by the application ICCSEL/VPP pin must be tied to VSS. 187/215 ST72F521, ST72521B 12.10 TIMER PERIPHERAL CHARACTERISTICS Subject to general operating conditions for VDD, fOSC, and TA unless otherwise specified. Refer to I/O port characteristics for more details on the input/output alternate function characteristics (output compare, input capture, external clock, PWM output...). 12.10.1 8-Bit PWM-ART Auto-Reload Timer Symbol Parameter tres(PWM) PWM resolution time Conditions fCPU=8MHz Min Typ Max 1 tCPU 125 ns fEXT ART external clock frequency 0 fCPU/2 fPWM PWM repetition rate 0 fCPU/2 ResPWM PWM resolution VOS PWM/DAC output step voltage Unit 8 VDD=5V, Res=8-bits 20 MHz bit mV 12.10.2 16-Bit Timer Symbol Parameter Conditions tw(ICAP)in Input capture pulse time tres(PWM) PWM resolution time fCPU=8MHz Min Typ Max Unit 1 tCPU 2 tCPU 250 ns fEXT Timer external clock frequency 0 fCPU/4 MHz fPWM PWM repetition rate 0 fCPU/4 MHz 16 bit ResPWM PWM resolution 188/215 ST72F521, ST72521B 12.11 COMMUNICATION INTERFACE CHARACTERISTICS 12.11.1 SPI - Serial Peripheral Interface Subject to general operating conditions for VDD, fCPU, and TA unless otherwise specified. Symbol Refer to I/O port characteristics for more details on the input/output alternate function characteristics (SS, SCK, MOSI, MISO). Parameter Conditions Master fSCK 1/tc(SCK) fCPU=8MHz SPI clock frequency Slave fCPU=8MHz tr(SCK) tf(SCK) SPI clock rise and fall time tsu(SS) SS setup time th(SS) Min Max fCPU/128 0.0625 fCPU/4 2 0 fCPU/2 4 120 SS hold time Slave 120 SCK high and low time Master Slave 100 90 tsu(MI) tsu(SI) Data input setup time Master Slave 100 100 th(MI) th(SI) Data input hold time Master Slave 100 100 ta(SO) Data output access time Slave 0 tdis(SO) Data output disable time Slave tv(SO) Data output valid time th(SO) Data output hold time tv(MO) Data output valid time th(MO) Data output hold time MHz see I/O port pin description Slave tw(SCKH) tw(SCKL) Unit ns 120 240 90 Slave (after enable edge) 0 Master (before capture edge) 0.25 tCPU 0.25 Figure 106. SPI Slave Timing Diagram with CPHA=0 3) SS INPUT SCK INPUT tsu(SS) tc(SCK) th(SS) CPHA=0 CPOL=0 CPHA=0 CPOL=1 ta(SO) MISO OUTPUT tw(SCKH) tw(SCKL) MSB OUT see note 2 tsu(SI) MOSI INPUT tv(SO) th(SO) BIT6 OUT tdis(SO) tr(SCK) tf(SCK) LSB OUT see note 2 th(SI) MSB IN BIT1 IN LSB IN Notes: 1. Data based on design simulation and/or characterisation results, not tested in production. 2. When no communication is on-going the data output line of the SPI (MOSI in master mode, MISO in slave mode) has its alternate function capability released. In this case, the pin status depends on the I/O port configuration. 3. Measurement points are done at CMOS levels: 0.3xVDD and 0.7xVDD. 189/215 ST72F521, ST72521B COMMUNICATION INTERFACE CHARACTERISTICS (Cont'd) Figure 107. SPI Slave Timing Diagram with CPHA=11) SS INPUT SCK INPUT tsu(SS) tc(SCK) th(SS) CPHA=1 CPOL=0 CPHA=1 CPOL=1 tw(SCKH) tw(SCKL) ta(SO) MISO OUTPUT see note 2 tv(SO) th(SO) MSB OUT HZ tsu(SI) BIT6 OUT LSB OUT see note 2 th(SI) MSB IN MOSI INPUT tdis(SO) tr(SCK) tf(SCK) BIT1 IN LSB IN Figure 108. SPI Master Timing Diagram 1) SS INPUT tc(SCK) SCK INPUT CPHA=0 CPOL=0 CPHA=0 CPOL=1 CPHA=1 CPOL=0 CPHA=1 CPOL=1 tw(SCKH) tw(SCKL) tsu(MI) MISO INPUT MOSI OUTPUT th(MI) MSB IN tv(MO) see note 2 tr(SCK) tf(SCK) BIT6 IN LSB IN th(MO) MSB OUT BIT6 OUT LSB OUT see note 2 Notes: 1. Measurement points are done at CMOS levels: 0.3xVDD and 0.7xVDD. 2. When no communication is on-going the data output line of the SPI (MOSI in master mode, MISO in slave mode) has its alternate function capability released. In this case, the pin status depends of the I/O port configuration. 190/215 ST72F521, ST72521B COMMUNICATION INTERFACE CHARACTERISTICS (Cont'd) 12.11.2 I2C - Inter IC Control Interface Subject to general operating conditions for VDD, fCPU, and TA unless otherwise specified. Symbol Refer to I/O port characteristics for more details on the input/output alternate function characteristics (SDAI and SCLI). The ST7 I2C interface meets the requirements of the Standard I2C communication protocol described in the following table. Standard mode I2C Parameter Min 1) Fast mode I2C5) Max 1) Min 1) Max 1) tw(SCLL) SCL clock low time 4.7 1.3 tw(SCLH) SCL clock high time 4.0 0.6 tsu(SDA) SDA setup time 250 100 3) 0 2) 900 3) 0 s th(SDA) SDA data hold time tr(SDA) tr(SCL) SDA and SCL rise time 1000 20+0.1Cb 300 tf(SDA) tf(SCL) SDA and SCL fall time 300 20+0.1Cb 300 th(STA) START condition hold time 4.0 0.6 tsu(STA) Repeated START condition setup time 4.7 0.6 tsu(STO) STOP condition setup time 4.0 0.6 tw(STO:STA) STOP to START condition time (bus free) 4.7 Capacitive load for each bus line Cb Unit ns s s s 1.3 400 400 pF Figure 109. Typical Application with I2C Bus and Timing Diagram 4) VDD 4.7k I2 C VDD 4.7k BUS 100 SDAI 100 SCLI ST72XXX REPEATED START START tsu(STA) tw(STO:STA) START SDA tr(SDA) tf(SDA) tsu(SDA) STOP th(SDA) SCK th(STA) tw(SCKH) tw(SCKL) tr(SCK) tf(SCK) tsu(STO) Notes: 1. Data based on standard I2C protocol requirement, not tested in production. 2. The device must internally provide a hold time of at least 300ns for the SDA signal in order to bridge the undefined region of the falling edge of SCL. 3. The maximum hold time of the START condition has only to be met if the interface does not stretch the low period of SCL signal. 4. Measurement points are done at CMOS levels: 0.3xVDD and 0.7xVDD. 5. At 4MHz fCPU, max.I2C speed (400kHz) is not achievable. In this case, max. I2C speed will be approximately 260KHz. 191/215 ST72F521, ST72521B COMMUNICATION INTERFACE CHARACTERISTICS (Cont'd) The following table gives the values to be written in the I2CCCR register to obtain the required I2C SCL line frequency. Table 28. SCL Frequency Table I2CCCR Value fSCL (kHz) 400 300 200 100 50 20 fCPU=4 MHz. VDD = 4.1 V RP=3.3k RP=4.7k NA NA NA NA 83h 83h 10h 10h 24h 24h 5Fh 5Fh VDD = 5 V RP=3.3k RP=4.7k NA NA NA NA 83h 83h 10h 10h 24h 24h 5Fh 5Fh fCPU=8 MHz. VDD = 4.1 V VDD = 5 V RP=3.3k RP=4.7k RP=3.3k RP=4.7k 83h 83 83h 83h 85h 85h 85h 85h 8Ah 89h 8Ah 8Ah 24h 23h 24h 23h 4Ch 4Ch 4Ch 4Ch FFh FFh FFh FFh Legend: RP = External pull-up resistance fSCL = I2C speed NA = Not achievable Note: - For speeds around 200 kHz, achieved speed can have 5% tolerance - For other speed ranges, achieved speed can have 2% tolerance The above variations depend on the accuracy of the external components used. 12.11.3 CAN - Controller Area Network Interface Subject to general operating condition for VDD, fOSC, and TA unless otherwise specified. Refer to I/O port characteristics for more details on the input/output alternate function characteristics (CANTX and CANRX). Symbol tp(RX:TX) Parameter CAN controller propagation time Conditions 1) Notes: 1. Data based on simulation results, not tested in production 192/215 Min Typ Max Unit 60 ns ST72F521, ST72521B 12.12 10-BIT ADC CHARACTERISTICS Subject to general operating conditions for VDD, fCPU, and TA unless otherwise specified. Symbol fADC VAREF VAIN Parameter Conditions ADC clock frequency 0.7*VDD VAREF VDD Analog reference voltage Conversion voltage range 1) Min Max Unit 0.4 Typ 2 MHz 3.8 VDD VSSA VAREF Positive input leakage current for analog -40CTA85C range input Other TA ranges Ilkg Negative input leakage current on robust analog pins (ROM devices only)2 VIN<VSS, | IIN |< 400A on adjacent robust analog pin 5 Positive input leakage current for analog -40CTA85C range input Other TA ranges Ilkg Negative input leakage current on robust analog pins (ROM devices only)2 RAIN External input impedance CAIN External capacitor on analog input fAIN Variation freq. of analog input signal VIN<VSS, | IIN |< 400A on adjacent robust analog pin 5 V 250 nA 1 A 6 A 250 nA 1 A 6 A see Figure 110 and Figure 1112)3)4) k pF Hz CADC Internal sample and hold capacitor 12 pF tADC Conversion time (Sample+Hold) fCPU=8MHz, SPEED=0 fADC=2MHz 7.5 s tADC - No of sample capacitor loading cycles - No. of Hold conversion cycles 4 11 1/fADC Notes: 1. Any added external serial resistor will downgrade the ADC accuracy (especially for resistance greater than 10k). Data based on characterization results, not tested in production. 2. For Flash devices: injecting negative current on any of the analog input pins significantly reduces the accuracy of any conversion being performed on any analog input. Analog pins of flash devices can be protected against negative injection by adding a Schottky diode (pin to ground). Injecting negative current on digital input pins degrades ADC accuracy especially if performed on a pin close to the analog input pins. Any positive injection current within the limits specified for IINJ(PIN) and IINJ(PIN) in Section 12.8 does not affect the ADC accuracy. 193/215 ST72F521, ST72521B ADC CHARACTERISTICS (Cont'd) Figure 110. RAIN max. vs fADC with CAIN=0pF1) Figure 111. Recommended CAIN & RAIN values.2) 45 1000 Cain 10 nF 2 MHz 35 30 1 MHz 25 Cain 22 nF 100 Max. R AIN (Kohm) Max. R AIN (Kohm) 40 20 15 10 Cain 47 nF 10 1 5 0 0.1 0 10 30 70 0.01 0.1 CPARASITIC (pF) 1 10 fAIN(KHz) Figure 112. Typical A/D Converter Application VDD RAIN AINx ST72XXX VT 0.6V 2k(max) VAIN CAIN VT 0.6V IL 1A 10-Bit A/D Conversion CADC 12pF Notes: 1. CPARASITIC represents the capacitance of the PCB (dependent on soldering and PCB layout quality) plus the pad capacitance (3pF). A high CPARASITIC value will downgrade conversion accuracy. To remedy this, fADC should be reduced. 2. This graph shows that depending on the input signal variation (fAIN), CAIN can be increased for stabilization time and decreased to allow the use of a larger serial resistor (RAIN). 194/215 ST72F521, ST72521B ADC CHARACTERISTICS (Cont'd) 12.12.1 Analog Power Supply and Reference Pins Depending on the MCU pin count, the package may feature separate VAREF and VSSA analog power supply pins. These pins supply power to the A/D converter cell and function as the high and low reference voltages for the conversion. Separation of the digital and analog power pins allow board designers to improve A/D performance. Conversion accuracy can be impacted by voltage drops and noise in the event of heavily loaded or badly decoupled power supply lines (see Section 12.12.2 General PCB Design Guidelines). 12.12.2 General PCB Design Guidelines To obtain best results, some general design and layout rules should be followed when designing the application PCB to shield the noise-sensitive, analog physical interface from noise-generating CMOS logic signals. - Use separate digital and analog planes. The analog ground plane should be connected to the digital ground plane via a single point on the PCB. - Filter power to the analog power planes. It is recommended to connect capacitors, with good high frequency characteristics, between the power and ground lines, placing 0.1F and optionally, if needed 10pF capacitors as close as possible to the ST7 power supply pins and a 1 to 10F capacitor close to the power source (see Figure 113). - The analog and digital power supplies should be connected in a star network. Do not use a resistor, as VAREF is used as a reference voltage by the A/D converter and any resistance would cause a voltage drop and a loss of accuracy. - Properly place components and route the signal traces on the PCB to shield the analog inputs. Analog signals paths should run over the analog ground plane and be as short as possible. Isolate analog signals from digital signals that may switch while the analog inputs are being sampled by the A/D converter. Do not toggle digital outputs on the same I/O port as the A/D input being converted. Figure 113. Power Supply Filtering ST72XXX 1 to 10F 0.1F ST7 DIGITAL NOISE FILTERING VSS VDD VDD POWER SUPPLY SOURCE 0.1F EXTERNAL NOISE FILTERING VAREF VSSA 195/215 ST72F521, ST72521B 10-BIT ADC CHARACTERISTICS (Cont'd) 12.12.3 ADC Accuracy Conditions: VDD=5V 1) Symbol |ET| |EO| |EG| Typ Max2) 3 4 2 3 0.5 3 CPU in run mode @ fADC 2 MHz. 1 2 CPU in run mode @ fADC 2 MHz. 1 2 Parameter Total unadjusted error Offset error Gain Error Conditions 1) 1) 1) |ED| Differential linearity error |EL| Integral linearity error 1) 1) Unit LSB Notes: 1. ADC Accuracy vs. Negative Injection Current: Injecting negative current may reduce the accuracy of the conversion being performed on another analog input. The effect of negative injection current on robust pins is specified in Section 12.12. Any positive injection current within the limits specified for IINJ(PIN) and IINJ(PIN) in Section 12.8 does not affect the ADC accuracy. 2. Data based on characterization results, monitored in production to guarantee 99.73% within max value from -40C to 125C ( 3 distribution limits). Figure 114. ADC Accuracy Characteristics Digital Result ADCDR EG 1023 1022 1LSB 1021 IDEAL V -V AREF SSA = -------------------------------------------- 1024 (2) ET ET=Total Unadjusted Error: maximum deviation between the actual and the ideal transfer curves. EO=Offset Error: deviation between the first actual transition and the first ideal one. EG=Gain Error: deviation between the last ideal transition and the last actual one. ED=Differential Linearity Error: maximum deviation between actual steps and the ideal one. EL=Integral Linearity Error: maximum deviation between any actual transition and the end point correlation line. (3) 7 (1) 6 5 EO 4 (1) Example of an actual transfer curve (2) The ideal transfer curve (3) End point correlation line EL 3 ED 2 1 LSBIDEAL 1 0 1 VSSA 196/215 Vin (LSBIDEAL) 2 3 4 5 6 7 1021 1022 1023 1024 VAREF ST72F521, ST72521B 13 PACKAGE CHARACTERISTICS 13.1 PACKAGE MECHANICAL DATA Figure 115. 80-Pin Thin Quad Flat Package Dim. D A D1 mm Min Typ A A2 A1 b inches Max Min Typ Max 1.60 0.063 0.15 0.002 0.006 A1 0.05 A2 1.35 1.40 1.45 0.053 0.055 0.057 b 0.22 0.32 0.38 0.009 0.013 0.015 C 0.09 0.20 0.004 0.008 D 16.00 0.630 D1 14.00 0.551 E 16.00 0.630 E1 14.00 0.551 e 0.65 0.026 e E1 E c L1 L 0 3.5 L 0.45 0.60 L1 h 7 0 3.5 7 0.75 0.018 0.024 0.030 1.00 0.039 Number of Pins N 80 Figure 116. 64-Pin Thin Quad Flat Package D A D1 A2 Dim. mm Min Typ A A1 b e E1 E L Max Min Typ Max 1.60 0.063 0.15 0.002 0.006 A1 0.05 A2 1.35 1.40 1.45 0.053 0.055 0.057 b 0.30 0.37 0.45 0.012 0.015 0.018 c 0.09 0.20 0.004 0.008 D 16.00 0.630 D1 14.00 0.551 0.630 E 16.00 E1 14.00 0.551 e 0.80 0.031 0 3.5 L 0.45 0.60 L1 L1 7 0 3.5 7 0.75 0.018 0.024 0.030 1.00 0.039 Number of Pins c h inches N 64 197/215 ST72F521, ST72521B PACKAGE MECHANICAL DATA (Cont'd) Figure 117. 64-Pin Thin Quad Flat Package Dim. D A D1 A2 b E e c L1 h L Typ A A1 E1 mm Min inches Max Min Typ 1.60 0.063 0.15 0.002 0.006 A1 0.05 A2 1.35 1.40 1.45 0.053 0.055 0.057 b 0.17 0.22 0.27 0.007 0.009 0.011 c 0.09 0.20 0.004 0.008 D 12.00 0.472 D1 10.00 0.394 E 12.00 0.472 E1 10.00 0.394 e 0.50 0.020 0 3.5 L 0.45 0.60 L1 7 0 3.5 N 7 0.75 0.018 0.024 0.030 1.00 0.039 Number of Pins 198/215 Max 64 ST72F521, ST72521B 13.2 THERMAL CHARACTERISTICS Symbol RthJA PD TJmax Ratings Value Unit Package thermal resistance (junction to ambient) TQFP80 14x14 TQFP64 14x14 TQFP64 10x10 55 47 50 C/W Power dissipation 1) 500 mW 150 C Maximum junction temperature 2) Notes: 1. The power dissipation is obtained from the formula PD=PINT+PPORT where PINT is the chip internal power (IDDxVDD) and PPORT is the port power dissipation determined by the user. 2. The average chip-junction temperature can be obtained from the formula TJ = TA + PD x RthJA. 199/215 ST72F521, ST72521B 13.3 SOLDERING INFORMATION In accordance with the RoHS European directive, all STMicroelectronics packages will be converted in 2005 to lead-free technology, named ECOPACKTM (for a detailed roadmap, please refer to PCN CRP/04/744 "Lead-free Conversion Program - Compliance with RoHS", issued November 18th, 2004). TM ECOPACK packages are qualified according to the JEDEC STD-020B compliant soldering profile. Detailed information on the STMicroelectronic ECOPACKTM transition program is available on www.st.com/stonline/leadfree/, with specific technical Application notes covering the main technical aspects related to lead-free conversion (AN2033, AN2034, AN2035, AN2036). Backward and forward compatibility: The main difference between Pb and Pb-free soldering process is the temperature range. - ECOPACKTM TQFP packages are fully compatible with Lead (Pb) containing soldering process (see application note AN2034) - TQFP Pb-packages are compatible with Leadfree soldering process, nevertheless it's the customer's duty to verify that the Pb-packages maximum temperature (mentioned on the Inner box label) is compatible with their Lead-free soldering temperature. Table 29. Soldering Compatibility (wave and reflow soldering process) Package TQFP Plating material devices NiPdAu (Nickel-palladium-Gold) Pb solder paste Yes Pb-free solder paste Yes * * Assemblers must verify that the Pb-package maximum temperature (mentioned on the Inner box label) is compatible with their Lead-free soldering process. 200/215 ST72F521, ST72521B 14 ST72521 DEVICE CONFIGURATION AND ORDERING INFORMATION Each device is available for production in user programmable versions (FLASH) as well as in factory coded versions (ROM/FASTROM). ST72521B devices are ROM versions. ST72P521 devices are Factory Advanced Service Technique ROM (FASTROM) versions: they are factory-programmed HDFlash devices. FLASH devices are shipped to customers with a default content, while ROM/FASTROM factory coded parts contain the code supplied by the customer. This implies that FLASH devices have to be configured by the customer using the Option Bytes while the ROM/FASTROM devices are factory-configured. 14.1 FLASH OPTION BYTES STATIC OPTION BYTE 0 STATIC OPTION BYTE 1 PKG1 RSTC 1 0 0 1 1 1 1 1 The option bytes allow the hardware configuration of the microcontroller to be selected. They have no address in the memory map and can be accessed only in programming mode (for example using a standard ST7 programming tool). The default content of the FLASH is fixed to FFh. To program the FLASH devices directly using ICP, FLASH devices are shipped to customers with the internal RC clock source. In masked ROM devices, the option bytes are fixed in hardware by the ROM code (see option list). OPTION BYTE 0 OPT7= WDG HALT Watchdog and HALT mode This option bit determines if a RESET is generated when entering HALT mode while the Watchdog is active. 0: No Reset generation when entering Halt mode 1: Reset generation when entering Halt mode OPT6= WDG SW Hardware or software watchdog This option bit selects the watchdog type. 0: Hardware (watchdog always enabled) OSCTYPE OSCRANGE 1 0 2 1 0 PLLOFF 0 FMP_R SW 1 Res. HALT 1 0 1 VD WDG Default 7 PKG0 0 Reserved 7 1 0 1 1 1 1 1: Software (watchdog to be enabled by software) OPT5 = Reserved, must be kept at default value. OPT4:3= VD[1:0] Voltage detection These option bits enable the voltage detection block (LVD, and AVD) with a selected threshold for the LVD and AVD (EVD+AVD). Selected Low Voltage Detector LVD and AVD Off Lowest Threshold: (VDD~3V) Med. Threshold (VDD~3.5V) Highest Threshold (VDD~4V) VD1 VD0 1 1 0 0 1 0 1 0 Caution: If the medium or low thresholds are selected, the detection may occur outside the specified operating voltage range. Below 3.8V, device operation is not guaranteed. For details on the AVD and LVD threshold levels refer to section 12.3.2 on page 168 201/215 ST72F521, ST72521B ST72521 DEVICE CONFIGURATION AND ORDERING INFORMATION (Cont'd) OPT2 = Reserved, must be kept at default value. OPT1= PKG0 Package selection bit 0 This option bit is used to select the package (see table in PKG1 option bit description). OPT0= FMP_R Flash memory read-out protection Read-out protection, when selected, provides a protection against Program Memory content extraction and against write access to Flash memory. Erasing the option bytes when the FMP_R option is selected causes the whole user memory to be erased first, and the device can be reprogrammed. Refer to Section 4.3.1 and the ST7 Flash Programming Reference Manual for more details. Note: Readout protection is not supported if LVD is enabled. 0: Read-out protection enabled 1: Read-out protection disabled OPT5:4 = OSCTYPE[1:0] Oscillator Type These option bits select the ST7 main clock source type. OSCTYPE Clock Source 1 0 Resonator Oscillator 0 0 Reserved 0 1 Internal RC Oscillator 1 0 External Source 1 1 OPT3:1 = OSCRANGE[2:0] Oscillator range When the resonator oscillator type is selected, these option bits select the resonator oscillator current source corresponding to the frequency range of the used resonator. Otherwise, these bits are used to select the normal operating frequency range. OSCRANGE OPTION BYTE 1 OPT7= PKG1 Package selection bit 1 This option bit, with the PKG0 bit, selects the package. Version Selected Package PKG 1 PKG 0 M TQFP80 1 1 (A)R TQFP64 1 0 Note: On the chip, each I/O port has 8 pads. Pads that are not bonded to external pins are in input pull-up configuration after reset. The configuration of these pads must be kept at reset state to avoid added current consumption. OPT6 = RSTC RESET clock cycle selection This option bit selects the number of CPU cycles applied during the RESET phase and when exiting HALT mode. For resonator oscillators, it is advised to select 4096 due to the long crystal stabilization time. 0: Reset phase with 4096 CPU cycles 1: Reset phase with 256 CPU cycles 202/215 Typ. Freq. Range 2 1 0 LP 1~2MHz 0 0 0 MP 2~4MHz 0 0 1 MS 4~8MHz 0 1 0 HS 8~16MHz 0 1 1 OPT0 = PLLOFF PLL activation This option bit activates the PLL which allows multiplication by two of the main input clock frequency. The PLL must not be used with the internal RC oscillator or with external clock source. The PLL is guaranteed only with an input frequency between 2 and 4MHz. 0: PLL x2 enabled 1: PLL x2 disabled CAUTION: the PLL can be enabled only if the "OSC RANGE" (OPT3:1) bits are configured to "MP - 2~4MHz". Otherwise, the device functionality is not guaranteed. ST72F521, ST72521B ST72521 DEVICE CONFIGURATION AND ORDERING INFORMATION (Cont'd) 14.2 DEVICE ORDERING INFORMATION AND TRANSFER OF CUSTOMER CODE Customer code is made up of the ROM/FASTROM contents and the list of the selected options (if any). The ROM/FASTROM contents are to be sent on diskette, or by electronic means, with the S19 hexadecimal file generated by the development tool. All unused bytes must be set to FFh. The selected options are communicated to STMicroelectronics using the correctly completed OPTION LIST appended. Refer to application note AN1635 for information on the counter listing returned by ST after code has been transferred. The STMicroelectronics Sales Organization will be pleased to provide detailed information on contractual points. 14.2.1 Version-Specific Sales Conditions To satisfy the different customer requirements and to ensure that ST Standard Microcontrollers will consistently meet or exceed the expectations of each Market Segment, the Codification System for Standard Microcontrollers clearly distinguishes products intended for use in automotive environments, from products intended for use in non-automotive environments. It is the responsibility of the Customer to select the appropriate product for his application. Figure 118. ROM Factory Coded Device Types DEVICE PACKAGE VERSION / XXX Code name (defined by STMicroelectronics) 1 = Standard 0 to +70 C 3 = Standard -40 to +125 C 5 = Standard -10 to +85 C 6 = Standard -40 to +85 C A = Automotive -40 to +85 C B = Automotive -40 to +105 C C = Automotive -40 to +125 C T= Plastic Thin Quad Flat Pack ST72521BR9, ST72521BR6 ST72521BAR9, ST72521BAR6 ST72521BM9 203/215 ST72F521, ST72521B ST72521 DEVICE CONFIGURATION AND ORDERING INFORMATION (Cont'd) ST72521B MICROCONTROLLER OPTION LIST (Last update: December 2004) Customer: Address: ................................ ................................ ................................ Contact: ................................ Phone No: ................................ Reference/ROM Code* : . . . . . . . . . . . . . . . . . . . . . . . *The ROM code name is assigned by STMicroelectronics. ROM code must be sent in .S19 format. .Hex extension cannot be processed. Device Type/Memory Size/Package (check only one option): --------------------------------- | ------------------------------------- | ------------------------------------ROM DEVICE: 60K 32K --------------------------------- | ------------------------------------- | ------------------------------------TQFP80: | [ ] ST72521BM9 | TQFP64 14x14: | [ ] ST72521BR9 | [ ] ST72521BR6 TQFP64 10x10: | [ ] ST72521BAR9 | [ ] ST72521BAR6 --------------------------------- | -------------------------------------- | ------------------------------------DIE FORM: 60K 32K --------------------------------- | -------------------------------------- | -------------------------------------80-pin: | [] | 64-pin: | [] | [] Conditioning (check only one option): ------------------------------------------------------------------------ | ----------------------------------------------------Packaged Product Die Product (dice tested at 25C only) | ---------------------------------------------------------------------------------------------------------------------------[ ] Tape & Reel [ ] Tray | [ ] Tape & Reel | [ ] Inked wafer | [ ] Sawn wafer on sticky foil Version/ Temp. Range (do not check for die product). Please refer to datasheet for specific sales conditions: ----------------------------- | ------------------------------------------- | ------------------------------------------Automotive Temp. Range Standard ----------------------------| ------------------------------------------- | ------------------------------------------[] | | [ ] 0C to +70C [] | | [ ] -10C to +85C [] | [] | [ ] -40C to +85C | [] | [ ] -40C to +105C | [] | [ ] -40C to +125C Special Marking: [ ] No [ ] Yes "_ _ _ _ _ _ _ _ _ _ " (10 char. max) Authorized characters are letters, digits, '.', '-', '/' and spaces only. Clock Source Selection: [ ] Resonator: [ ] LP: Low power resonator (1 to 2 MHz) [ ] MP: Medium power resonator (2 to 4 MHz) [ ] MS: Medium speed resonator (4 to 8 MHz) [ ] HS: High speed resonator (8 to 16 MHz) [ ] Internal RC: [ ] External Clock PLL LVD Reset [ ] Disabled Reset Delay Watchdog Selection: Watchdog Reset on Halt: Readout Protection: Date Signature [ ] Disabled [ ] Enabled [ ] High threshold [ ] Med. threshold [ ] Low threshold [ ] 256 Cycles [ ] 4096 Cycles [ ] Software Activation [ ] Hardware Activation [ ] Reset [ ] No Reset [ ] Disabled [ ] Enabled ................................ ................................ Please download the latest version of this option list from: http://www.st.com/mcu > downloads > ST7 microcontrollers > Option list 204/215 ST72F521, ST72521B DEVICE CONFIGURATION AND ORDERING INFORMATION (Cont'd) Table 30. Orderable Flash Device Types Part Number Version ST72F521AR6TC TQFP64 10 x 10 ST72F521AR9TC ST72F521R6TC Automotive ST72F521R9TC ST72F521M9TC TQFP64 10 x 10 ST72F521AR9T3 Standard ST72F521R9T3 ST72F521M9T3 TQFP64 10 x 10 ST72F521AR9T6 ST72F521R9T6 ST72F521M9T6 TQFP64 14 x 14 TQFP80 ST72F521AR6T6 ST72F521R6T6 TQFP64 14 x 14 TQFP80 ST72F521AR6T3 ST72F521R6T3 Package Standard TQFP64 14 x 14 TQFP80 Flash Memory (Kbytes) Temp. Range 32 60 32 -40C +125C 60 60 32 60 32 -40C +125C 60 60 32 60 32 -40C +85C 60 60 205/215 ST72F521, ST72521B DEVICE CONFIGURATION AND ORDERING INFORMATION (Cont'd) 14.3 DEVELOPMENT TOOLS STMicroelectronics offers a range of hardware and software development tools for the ST7 microcontroller family. Full details of tools available for the ST7 from third party manufacturers can be obtained from the STMicroelectronics Internet site: http//www.st.com. Tools from these manufacturers include C compliers, evaluation tools, emulators and programmers. Emulators Two types of emulators are available from ST for the ST725 family: ST7 DVP3 entry-level emulator offers a flexible and modular debugging and programming solution. SDIP42 & SDIP32 probes/adapters are included, other packages need a specific connection kit (refer to Table 31) ST7 EMU3 high-end emulator is delivered with everything (probes, TEB, adapters etc.) needed to start emulating the ST725. To configure it to emulate other ST7 subfamily devices, the active probe for the ST7EMU3 can be changed and the ST7EMU3 probe is designed for easy interchange of TEBs (Target Emulation Board). See Table 31. In-circuit Debugging Kit Two configurations are available from ST: STXF521-IND/USB: Low-cost In-Circuit Debugging kit from Softec Microsystems. Includes STX-InDART/USB board (USB port) and a specific demo board for ST72521 (TQFP64) STxF-INDART Flash Programming tools ST7-STICK ST7 In-circuit Communication Kit, a complete software/hardware package for programming ST7 Flash devices. It connects to a host PC parallel port and to the target board or socket board via ST7 ICC connector. ICC Socket Boards provide an easy to use and flexible means of programming ST7 Flash devices. They can be connected to any tool that supports the ST7 ICC interface, such as ST7 EMU3, ST7-DVP3, inDART, ST7-STICK, or many third-party development tools. Evaluation boards Three different Evaluation boards are available: ST7232x-EVAL ST72F321/325/521 evaluation board, with ICC connector for programming capability. Provides direct connection to ST7DVP3 emulator. Supplied with daughter boards (core module) for ST72F321, ST72F324, ST72325 & ST72F521 (the ST72F32x chips are not included) 1 ST7MDT20-EVC/xx with CAB TQFP64 14x14 socket 1 ST7MDT20-EVY/xx with Yamaichi TQFP64 10x10 socket Table 31. STMicroelectronics Development Tools Emulation Supported Products ST7 DVP3 Series Emulator ST72521R, ST72F521R Emulator Active Probe & T.E.B. ICC Socket Board ST7MDT20MEMU3 ST7MDT20M-TEB ST7SB20M/xx1 ST7MDT20-T80/ DVP ST72521M, ST72F521M ST72521AR, ST72F521AR Connection kit Programming ST7 EMU3 series ST7MDT20-DVP3 ST7MDT20-T6A/ DVP ST7MDT20-T64/ DVP Note 1: Add suffix /EU, /UK, /US for the power supply of your region. 206/215 ST72F521, ST72521B DEVICE CONFIGURATION AND ORDERING INFORMATION (Cont'd) Table 32. Suggested List of Socket Types Device Socket (supplied with ST7MDT20MEMU3) Emulator Adapter (supplied with ST7MDT20M-EMU3) TQFP64 14 x14 CAB 3303262 CAB 3303351 TQFP64 10 x10 YAMAICHI IC149-064-*75-*5 YAMAICHI ICP-064-6 TQFP80 14 X 14 YAMAICHI IC149-080-*51-*5 YAMAICHI ICP-080-7 14.3.1 Socket and Emulator Adapter Information For information on the type of socket that is supplied with the emulator, refer to the suggested list of sockets in Table 32. Note: Before designing the board layout, it is recommended to check the overall dimensions of the socket as they may be greater than the dimensions of the device. For footprint and other mechanical information about these sockets and adapters, refer to the manufacturer's datasheet (www.yamaichi.de for TQFP64 10 x 10 and TQFP80 14 x 14 and www.cabgmbh.com for TQFP64 14 x 14) Related Documentation AN 978: ST7 Visual Develop Software Key Debugging Features AN 1938: ST7 Visual Develop for ST7 Cosmic C toolset users AN 1939: ST7 Visual Develop for ST7 Metroworks C toolset users AN 1940: ST7 Visual Develop for ST7 Assembler Linker toolset users 207/215 ST72F521, ST72521B 14.4 ST7 APPLICATION NOTES Table 33. ST7 Application Notes IDENTIFICATION DESCRIPTION APPLICATION EXAMPLES AN1658 SERIAL NUMBERING IMPLEMENTATION AN1720 MANAGING THE READ-OUT PROTECTION IN FLASH MICROCONTROLLERS AN1755 A HIGH RESOLUTION/PRECISION THERMOMETER USING ST7 AND NE555 AN1756 CHOOSING A DALI IMPLEMENTATION STRATEGY WITH ST7DALI EXAMPLE DRIVERS AN 969 SCI COMMUNICATION BETWEEN ST7 AND PC AN 970 SPI COMMUNICATION BETWEEN ST7 AND EEPROM AN 971 IC COMMUNICATION BETWEEN ST7 AND M24CXX EEPROM AN 972 ST7 SOFTWARE SPI MASTER COMMUNICATION AN 973 SCI SOFTWARE COMMUNICATION WITH A PC USING ST72251 16-BIT TIMER AN 974 REAL TIME CLOCK WITH ST7 TIMER OUTPUT COMPARE AN 976 DRIVING A BUZZER THROUGH ST7 TIMER PWM FUNCTION AN 979 DRIVING AN ANALOG KEYBOARD WITH THE ST7 ADC AN 980 ST7 KEYPAD DECODING TECHNIQUES, IMPLEMENTING WAKE-UP ON KEYSTROKE AN1017 USING THE ST7 UNIVERSAL SERIAL BUS MICROCONTROLLER AN1041 USING ST7 PWM SIGNAL TO GENERATE ANALOG OUTPUT (SINUSOID) AN1042 ST7 ROUTINE FOR IC SLAVE MODE MANAGEMENT AN1044 MULTIPLE INTERRUPT SOURCES MANAGEMENT FOR ST7 MCUS AN1045 ST7 S/W IMPLEMENTATION OF IC BUS MASTER AN1046 UART EMULATION SOFTWARE AN1047 MANAGING RECEPTION ERRORS WITH THE ST7 SCI PERIPHERALS AN1048 ST7 SOFTWARE LCD DRIVER AN1078 PWM DUTY CYCLE SWITCH IMPLEMENTING TRUE 0% & 100% DUTY CYCLE AN1082 DESCRIPTION OF THE ST72141 MOTOR CONTROL PERIPHERALS REGISTERS AN1083 ST72141 BLDC MOTOR CONTROL SOFTWARE AND FLOWCHART EXAMPLE AN1105 ST7 PCAN PERIPHERAL DRIVER AN1129 PWM MANAGEMENT FOR BLDC MOTOR DRIVES USING THE ST72141 AN INTRODUCTION TO SENSORLESS BRUSHLESS DC MOTOR DRIVE APPLICATIONS AN1130 WITH THE ST72141 AN1148 USING THE ST7263 FOR DESIGNING A USB MOUSE AN1149 HANDLING SUSPEND MODE ON A USB MOUSE AN1180 USING THE ST7263 KIT TO IMPLEMENT A USB GAME PAD AN1276 BLDC MOTOR START ROUTINE FOR THE ST72141 MICROCONTROLLER AN1321 USING THE ST72141 MOTOR CONTROL MCU IN SENSOR MODE AN1325 USING THE ST7 USB LOW-SPEED FIRMWARE V4.X AN1445 EMULATED 16 BIT SLAVE SPI AN1475 DEVELOPING AN ST7265X MASS STORAGE APPLICATION AN1504 STARTING A PWM SIGNAL DIRECTLY AT HIGH LEVEL USING THE ST7 16-BIT TIMER AN1602 16-BIT TIMING OPERATIONS USING ST7262 OR ST7263B ST7 USB MCUS AN1633 DEVICE FIRMWARE UPGRADE (DFU) IMPLEMENTATION IN ST7 NON-USB APPLICATIONS AN1712 GENERATING A HIGH RESOLUTION SINEWAVE USING ST7 PWMART AN1713 SMBUS SLAVE DRIVER FOR ST7 I2C PERIPHERALS AN1753 SOFTWARE UART USING 12-BIT ART AN1947 ST7MC PMAC SINE WAVE MOTOR CONTROL SOFTWARE LIBRARY 208/215 ST72F521, ST72521B Table 33. ST7 Application Notes IDENTIFICATION DESCRIPTION GENERAL PURPOSE AN1476 LOW COST POWER SUPPLY FOR HOME APPLIANCES AN1526 ST7FLITE0 QUICK REFERENCE NOTE AN1709 EMC DESIGN FOR ST MICROCONTROLLERS AN1752 ST72324 QUICK REFERENCE NOTE PRODUCT EVALUATION AN 910 PERFORMANCE BENCHMARKING AN 990 ST7 BENEFITS VERSUS INDUSTRY STANDARD AN1077 OVERVIEW OF ENHANCED CAN CONTROLLERS FOR ST7 AND ST9 MCUS AN1086 U435 CAN-DO SOLUTIONS FOR CAR MULTIPLEXING AN1103 IMPROVED B-EMF DETECTION FOR LOW SPEED, LOW VOLTAGE WITH ST72141 AN1150 BENCHMARK ST72 VS PC16 AN1151 PERFORMANCE COMPARISON BETWEEN ST72254 & PC16F876 AN1278 LIN (LOCAL INTERCONNECT NETWORK) SOLUTIONS PRODUCT MIGRATION AN1131 MIGRATING APPLICATIONS FROM ST72511/311/214/124 TO ST72521/321/324 AN1322 MIGRATING AN APPLICATION FROM ST7263 REV.B TO ST7263B AN1365 GUIDELINES FOR MIGRATING ST72C254 APPLICATIONS TO ST72F264 AN1604 HOW TO USE ST7MDT1-TRAIN WITH ST72F264 PRODUCT OPTIMIZATION AN 982 USING ST7 WITH CERAMIC RESONATOR AN1014 HOW TO MINIMIZE THE ST7 POWER CONSUMPTION AN1015 SOFTWARE TECHNIQUES FOR IMPROVING MICROCONTROLLER EMC PERFORMANCE AN1040 MONITORING THE VBUS SIGNAL FOR USB SELF-POWERED DEVICES AN1070 ST7 CHECKSUM SELF-CHECKING CAPABILITY AN1181 ELECTROSTATIC DISCHARGE SENSITIVE MEASUREMENT AN1324 CALIBRATING THE RC OSCILLATOR OF THE ST7FLITE0 MCU USING THE MAINS AN1502 EMULATED DATA EEPROM WITH ST7 HDFLASH MEMORY AN1529 EXTENDING THE CURRENT & VOLTAGE CAPABILITY ON THE ST7265 VDDF SUPPLY ACCURATE TIMEBASE FOR LOW-COST ST7 APPLICATIONS WITH INTERNAL RC OSCILLAAN1530 TOR AN1605 USING AN ACTIVE RC TO WAKEUP THE ST7LITE0 FROM POWER SAVING MODE AN1636 UNDERSTANDING AND MINIMIZING ADC CONVERSION ERRORS AN1828 PIR (PASSIVE INFRARED) DETECTOR USING THE ST7FLITE05/09/SUPERLITE AN1946 SENSORLESS BLDC MOTOR CONTROL AND BEMF SAMPLING METHODS WITH ST7MC AN1971 ST7LITE0 MICROCONTROLLED BALLAST PROGRAMMING AND TOOLS AN 978 ST7 VISUAL DEVELOP SOFTWARE KEY DEBUGGING FEATURES AN 983 KEY FEATURES OF THE COSMIC ST7 C-COMPILER PACKAGE AN 985 EXECUTING CODE IN ST7 RAM AN 986 USING THE INDIRECT ADDRESSING MODE WITH ST7 AN 987 ST7 SERIAL TEST CONTROLLER PROGRAMMING AN 988 STARTING WITH ST7 ASSEMBLY TOOL CHAIN AN 989 GETTING STARTED WITH THE ST7 HIWARE C TOOLCHAIN AN1039 ST7 MATH UTILITY ROUTINES AN1064 WRITING OPTIMIZED HIWARE C LANGUAGE FOR ST7 AN1071 HALF DUPLEX USB-TO-SERIAL BRIDGE USING THE ST72611 USB MICROCONTROLLER 209/215 ST72F521, ST72521B Table 33. ST7 Application Notes IDENTIFICATION AN1106 DESCRIPTION TRANSLATING ASSEMBLY CODE FROM HC05 TO ST7 PROGRAMMING ST7 FLASH MICROCONTROLLERS IN REMOTE ISP MODE (IN-SITU PROAN1179 GRAMMING) AN1446 USING THE ST72521 EMULATOR TO DEBUG A ST72324 TARGET APPLICATION AN1477 EMULATED DATA EEPROM WITH XFLASH MEMORY AN1478 PORTING AN ST7 PANTA PROJECT TO CODEWARRIOR IDE AN1527 DEVELOPING A USB SMARTCARD READER WITH ST7SCR AN1575 ON-BOARD PROGRAMMING METHODS FOR XFLASH AND HDFLASH ST7 MCUS AN1576 IN-APPLICATION PROGRAMMING (IAP) DRIVERS FOR ST7 HDFLASH OR XFLASH MCUS AN1577 DEVICE FIRMWARE UPGRADE (DFU) IMPLEMENTATION FOR ST7 USB APPLICATIONS AN1601 SOFTWARE IMPLEMENTATION FOR ST7DALI-EVAL AN1603 USING THE ST7 USB DEVICE FIRMWARE UPGRADE DEVELOPMENT KIT (DFU-DK) AN1635 ST7 CUSTOMER ROM CODE RELEASE INFORMATION AN1754 DATA LOGGING PROGRAM FOR TESTING ST7 APPLICATIONS VIA ICC AN1796 FIELD UPDATES FOR FLASH BASED ST7 APPLICATIONS USING A PC COMM PORT AN1900 HARDWARE IMPLEMENTATION FOR ST7DALI-EVAL AN1904 ST7MC THREE-PHASE AC INDUCTION MOTOR CONTROL SOFTWARE LIBRARY AN1905 ST7MC THREE-PHASE BLDC MOTOR CONTROL SOFTWARE LIBRARY SYSTEM OPTIMIZATION AN1711 SOFTWARE TECHNIQUES FOR COMPENSATING ST7 ADC ERRORS AN1827 IMPLEMENTATION OF SIGMA-DELTA ADC WITH ST7FLITE05/09 AN2009 PWM MANAGEMENT FOR 3-PHASE BLDC MOTOR DRIVES USING THE ST7FMC AN2030 BACK EMF DETECTION DURING PWM ON TIME BY ST7MC 210/215 ST72F521, ST72521B 15 KNOWN LIMITATIONS 15.1 ALL FLASH AND ROM DEVICES 15.1.1 External RC option The External RC clock source option described in previous datasheet revisions is no longer supported and has been removed from this specification. 15.1.2 Safe Connection of OSC1/OSC2 Pins The OSC1 and/or OSC2 pins must not be left unconnected otherwise the ST7 main oscillator may start and, in this configuration, could generate an fOSC clock frequency in excess of the allowed maximum (>16MHz.), putting the ST7 in an unsafe/undefined state. Refer to section 6.2 on page 25. 15.1.3 Reset pin protection with LVD Enabled As mentioned in note 2 below Figure 103 on page 186, when the LVD is enabled, it is recommended not to connect a pull-up resistor or capacitor. A 10nF pull-down capacitor is required to filter noise on the reset line. 15.1.4 Unexpected Reset Fetch If an interrupt request occurs while a "POP CC" instruction is executed, the interrupt controller does not recognise the source of the interrupt and, by default, passes the RESET vector address to the CPU. Workaround To solve this issue, a "POP CC" instruction must always be preceded by a "SIM" instruction. 15.1.5 Clearing active interrupts outside interrupt routine When an active interrupt request occurs at the same time as the related flag is being cleared, an unwanted reset may occur. Note: clearing the related interrupt mask will not generate an unwanted reset Concurrent interrupt context The symptom does not occur when the interrupts are handled normally, i.e. when: - The interrupt flag is cleared within its own interrupt routine - The interrupt flag is cleared within any interrupt routine - The interrupt flag is cleared in any part of the code while this interrupt is disabled If these conditions are not met, the symptom can be avoided by implementing the following sequence: Perform SIM and RIM operation before and after resetting an active interrupt request. Example: SIM reset interrupt flag RIM Nested interrupt context: The symptom does not occur when the interrupts are handled normally, i.e. when: - The interrupt flag is cleared within its own interrupt routine - The interrupt flag is cleared within any interrupt routine with higher or identical priority level - The interrupt flag is cleared in any part of the code while this interrupt is disabled If these conditions are not met, the symptom can be avoided by implementing the following sequence: PUSH CC SIM reset interrupt flag POP CC 211/215 ST72F521, ST72521B KNOWN LIMITATIONS (Cont'd) 15.1.6 SCI Wrong Break duration Description A single break character is sent by setting and resetting the SBK bit in the SCICR2 register. In some cases, the break character may have a longer duration than expected: - 20 bits instead of 10 bits if M=0 - 22 bits instead of 11 bits if M=1. In the same way, as long as the SBK bit is set, break characters are sent to the TDO pin. This may lead to generate one break more than expected. Occurrence The occurrence of the problem is random and proportional to the baudrate. With a transmit frequency of 19200 baud (fCPU=8MHz and SCIBRR=0xC9), the wrong break duration occurrence is around 1%. Workaround If this wrong duration is not compliant with the communication protocol in the application, software can request that an Idle line be generated before the break character. In this case, the break duration is always correct assuming the application is not doing anything between the idle and the break. This can be ensured by temporarily disabling interrupts. The exact sequence is: - Disable interrupts - Reset and Set TE (IDLE request) - Set and Reset SBK (Break Request) - Re-enable interrupts 212/215 15.1.7 16-bit Timer PWM Mode In PWM mode, the first PWM pulse is missed after writing the value FFFCh in the OC1R register (OC1HR, OC1LR). It leads to either full or no PWM during a period, depending on the OLVL1 and OLVL2 settings. 15.1.8 CAN Cell Limitations Limitation1 Omitted SOF bit CPU write access (more than one cycle) corrupts CAN frame Unexpected Message transmission Bus Off State Not Entered WKPS Functionality Flash x ROM x x x x2 x4 x3 x=limitation present For details see section 10.8.5 on page 146 2 Software workaround possible using modified WKPS bit. 3Functionality modified for Unexpected Message Transmission workaround in Flash. 4 Limitation present on ROM Rev W and Rev Z. Not present in Flash and ROM Rev Y. 15.1.9 I2C Multimaster In multimaster configurations, if the ST7 I2C receives a START condition from another I2C master after the START bit is set in the I2CCR register and before the START condition is generated by the ST7 I2C, it may ignore the START condition from the other I2C master. In this case, the ST7 master will receive a NACK from the other device. On reception of the NACK, ST7 can send a re-start and Slave address to re-initiate communication 1 ST72F521, ST72521B KNOWN LIMITATIONS (Cont'd) 15.2 ALL FLASH DEVICES 15.2.1 Internal RC Oscillator with LVD The internal RC can only be used if LVD is enabled. 15.2.2 I/O behaviour during ICC mode entry sequence Symptom In 80-pin devices (Flash), both Port G and H are forced to output push-pull during ICC mode entry sequence. 80-pin ROM devices are not impacted by this issue. Details To enable programming of all flash sectors, the device must leave USER mode and be configured in ICC mode. Once in ICC mode, the ICC protocol enables an ST7 microcontroller to communicate with an external controller (such as a PC). ICC mode is entered by applying 39 pulses on the ICCDATA signal during reset. To enter ICC mode, the device goes through other modes, some modes are critical because the I/Os PG[7:0] and PH[7:0] are forced to output push-pull. Impact on the Application The PG and PH I/O ports are forced to output push-pull during three pulses on ICCDATA. In certain circumstances, this behaviour can lead to a short-circuit between the I/O signals and VDD, VSS or an output signal of another application component. In addition, switching these I/Os to output mode can cause the application to leave reset state, disturbing the ICC communication and preventing the user from programming the flash. 15.2.3 Read-out protection with LVD The LVD is not supported if Readout protection is enabled. 213/215 ST72F521, ST72521B 16 REVISION HISTORY Table 34. Revision History Date Revision Description of Changes Added Figure 82 on page 153 7-Dec-2004 3 Reinstated "I/O behaviour during ICC mode entry sequence" on page 213 Reinstated "BUSOFF not entered" in "CAN Cell Limitations" on page 212 Added "flash only" to PC6 Iinj spec in Section 12.2 and Section 12.8 Added Note on SMbus to Section 10.7 Static current consumption modified in section 12.8 on page 182 4-Mar-2005 4 Updated footnote and Figure 103 and Figure 104 on page 186 Modified VtPOR in section 12.3.2 on page 168 Added note 4 below Table of "CAN Cell Limitations" on page 212 Corrected MCO description in Table 1 and Section 10.2 Updated footnotes and Figure 103 and Figure 104 on page 186. 18-May-2005 5 Updated soldering information in section 13.3 on page 200 Added Suffix 3 to Figure 118 on page 203 Updated partnumbers in Table 30 on page 205 Added "Reset pin protection with LVD Enabled" on page 211 214/215 ST72F521, ST72521B Notes: Information furnished is believed to be accurate and reliable. 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