ST72321M6
ST72321M9
80-pin 8-bit MCU with 32 to 60 Kbytes Flash, ADC,
five timers, SPI, SCI, I2C interface
Features
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Memories
– 32 Kbytes to 60 Kbytes dual voltage High
Density Flash (HDFlash) with read-out protection capability. In-application programming
and In-circuit programming.
– 1 Kbyte to 2 Kbytes RAM
– HDFlash endurance: 100 cycles at 85 °C;
data retention: 40 years at 85 °C
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
– 64 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
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LQFP80
14 x 14
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event detector
4 Communication interfaces
– SPI synchronous serial interface
– SCI asynchronous serial interface
– I2C multimaster interface
(SMbus V1.1 compliant)
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
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Table 1. Device summary
Features
Flash program memory
RAM (stack) - bytes
Operating voltage
Temperature range
Package
May 2009
ST72321M9
ST72321M6
60 Kbytes
2048 bytes (256 bytes)
32 Kbytes
1024 (256 bytes)
3.8 V to 5.5 V
-40 °C to +85 °C
LQFP80 14x14
Doc ID 12706 Rev 2
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Table of Contents
1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2 PIN DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3 REGISTER & MEMORY MAP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4 FLASH PROGRAM MEMORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.2 MAIN FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.3 STRUCTURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.3.1 Read-out Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.4 ICC INTERFACE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4.5 ICP (IN-CIRCUIT PROGRAMMING) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
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4.6 IAP (IN-APPLICATION PROGRAMMING) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
4.7 RELATED DOCUMENTATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
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4.7.1 Register Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
5 CENTRAL PROCESSING UNIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
5.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
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5.2 MAIN FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
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5.3 CPU REGISTERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
6 SUPPLY, RESET AND CLOCK MANAGEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
6.1 PHASE LOCKED LOOP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
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6.2 MULTI-OSCILLATOR (MO) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
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6.3 RESET SEQUENCE MANAGER (RSM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
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) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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7.2 MASKING AND PROCESSING FLOW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
7.3 INTERRUPTS AND LOW POWER MODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
7.4 CONCURRENT & NESTED MANAGEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
7.5 INTERRUPT REGISTER DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
7.6 EXTERNAL INTERRUPTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
7.6.1 I/O Port Interrupt Sensitivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
7.7 EXTERNAL INTERRUPT CONTROL REGISTER (EICR) . . . . . . . . . . . . . . . . . . . . . . . . . 39
8 POWER SAVING MODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
8.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175
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8.2 SLOW MODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
8.3 WAIT MODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
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8.4 ACTIVE-HALT AND HALT MODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
8.4.1 ACTIVE-HALT MODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.4.2 HALT MODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.4.3 I/O Port Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9 ON-CHIP PERIPHERALS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.1 WATCHDOG TIMER (WDG) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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9.1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.1.2 Main Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.1.3 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.1.4 How to Program the Watchdog Timeout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.1.5 Low Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.1.6 Hardware Watchdog Option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.1.7 Using Halt Mode with the WDG (WDGHALT option) . . . . . . . . . . . . . . . . . . . . . . .
9.1.8 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.1.9 Register Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.2 MAIN CLOCK CONTROLLER WITH REAL-TIME CLOCK AND BEEPER (MCC/RTC) . .
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9.2.1 Programmable CPU Clock Prescaler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.2.2 Clock-out Capability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.2.3 Real-Time Clock Timer (RTC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.2.4 Beeper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.2.5 Low Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.2.6 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.2.7 Register Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.3 PWM AUTO-RELOAD TIMER (ART) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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9.3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.3.2 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.3.3 Register Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.4 16-BIT TIMER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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9.4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.4.2 Main Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.4.3 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.4.4 Low Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.4.5 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.4.6 Summary of Timer Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.4.7 Register Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.5 SERIAL PERIPHERAL INTERFACE (SPI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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9.5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.5.2 Main Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.5.3 General Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.5.4 Clock Phase and Clock Polarity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.5.5 Error Flags . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.5.6 Low Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.5.7 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.5.8 Register Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.6 SERIAL COMMUNICATIONS INTERFACE (SCI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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9.6.1
9.6.2
9.6.3
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
Main Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
General Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
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9.6.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
9.6.5 Low Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
9.6.6 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
9.6.7 Register Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
9.7 I2C BUS INTERFACE (I2C) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
9.7.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.7.2 Main Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.7.3 General Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.7.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.7.5 Low Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.7.6 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.7.7 Register Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.8 10-BIT A/D CONVERTER (ADC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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9.8.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.8.2 Main Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.8.3 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.8.4 Low Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.8.5 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.8.6 Register Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10 INSTRUCTION SET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10.1 CPU ADDRESSING MODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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10.1.1 Inherent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10.1.2 Immediate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10.1.3 Direct . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10.1.4 Indexed (No Offset, Short, Long) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10.1.5 Indirect (Short, Long) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10.1.6 Indirect Indexed (Short, Long) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10.1.7 Relative mode (Direct, Indirect) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10.2 INSTRUCTION GROUPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
129
129
129
129
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130
130
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11 ELECTRICAL CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
11.1 PARAMETER CONDITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
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11.1.1 Minimum and Maximum values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.1.2 Typical values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.1.3 Typical curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.1.4 Loading capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.1.5 Pin input voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.2 ABSOLUTE MAXIMUM RATINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
134
134
134
134
134
135
11.2.1 Voltage Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.2.2 Current Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.2.3 Thermal Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.3 OPERATING CONDITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
135
135
136
136
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11.3.1 General Operating Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
11.3.2 Operating Conditions with Low Voltage Detector (LVD) . . . . . . . . . . . . . . . . . . . 137
11.3.3 Auxiliary Voltage Detector (AVD) Thresholds . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
11.3.4 External Voltage Detector (EVD) Thresholds . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
11.4 SUPPLY CURRENT CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175
. . . 138
11.4.1 CURRENT CONSUMPTION
4/175
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
Table of Contents
11.4.2 Supply and Clock Managers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
11.4.3 On-Chip Peripherals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
11.5 CLOCK AND TIMING CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142
11.5.1 General Timings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.5.2 External Clock Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.5.3 Crystal and Ceramic Resonator Oscillators . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.5.4 RC Oscillators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.5.5 PLL Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.6 MEMORY CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
142
142
143
145
146
147
11.6.1 RAM and Hardware Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
11.6.2 Flash memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
11.7 EMC CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148
11.7.1 Functional EMS (Electro Magnetic Susceptibility) . . . . . . . . . . . . . . . . . . . . . . . .
11.7.2 Electro Magnetic Interference (EMI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.7.3 Absolute Maximum Ratings (Electrical Sensitivity) . . . . . . . . . . . . . . . . . . . . . . .
11.8 I/O PORT PIN CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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150
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11.8.1 General Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
11.8.2 Output Driving Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152
11.9 CONTROL PIN CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154
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11.9.1 Asynchronous RESET Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154
11.9.2 ICCSEL/VPP Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
11.10TIMER PERIPHERAL CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
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11.10.1 8-Bit PWM-ART Auto-Reload Timer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
11.10.2 16-Bit Timer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
11.11COMMUNICATION INTERFACE CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . 158
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11.11.1 SPI - Serial Peripheral Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158
11.11.2 I2C - Inter IC Control Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160
11.1210-BIT ADC CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
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11.12.1 Analog Power Supply and Reference Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.12.2 General PCB Design Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.12.3 ADC Accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12 PACKAGE CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12.1 ECOPACK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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164
165
166
166
12.2 PACKAGE MECHANICAL DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166
12.3 THERMAL CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166
13 ST72321Mx DEVICE CONFIGURATION AND ORDERING INFORMATION . . . . . . . . . . . . 167
13.1 FLASH OPTION BYTES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167
13.2 DEVICE ORDERING INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169
14 KNOWN LIMITATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170
14.1 SAFE CONNECTION OF OSC1/OSC2 PINS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170
14.2 RESET PIN PROTECTION WITH LVD ENABLED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170
14.3 UNEXPECTED RESET FETCH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170
14.4 EXTERNAL INTERRUPT MISSED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170
14.5 CLEARING ACTIVE INTERRUPTS OUTSIDE INTERRUPT ROUTINE . . . . . . . . . . . . . 171
14.6 SCI WRONG BREAK DURATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172
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Table of Contents
14.7 16-BIT TIMER PWM MODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172
14.8 TIMD SET SIMULTANEOUSLY WITH OC INTERRUPT . . . . . . . . . . . . . . . . . . . . . . . . . 172
14.9 I2C MULTIMASTER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172
14.10INTERNAL RC OSCILLATOR WITH LVD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172
14.11I/O BEHAVIOUR DURING ICC MODE ENTRY SEQUENCE . . . . . . . . . . . . . . . . . . . . 172
14.12READ-OUT PROTECTION WITH LVD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173
15 REVISION HISTORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174
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ST72321M6 ST72321M9
1 INTRODUCTION
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.
The ST72321Mx Flash devices are members of
the ST7 microcontroller family designed for midrange applications.
All devices are based on a common industrystandard 8-bit core, featuring an enhanced instruction set and are available with Flash memory.
Under software control, all devices can be placed
in Wait, Slow, Active-halt or Halt mode, reducing
Figure 1. Device Block Diagram
8-BIT CORE
ALU
RESET
VPP
TLI
VSS
VDD
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PROGRAM
MEMORY
(32 - 60 Kbytes)
RAM
(1024-2048 Bytes)
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LVD
EVD
AVD
OSC1
OSC2
OSC
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CONTROL
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WATCHDOG
ct
PORT F
PF7:0
(8-bits)
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TIMER A
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s
Pr
BEEP
ADDRESS AND DATA BUS
)
(s
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)
SPI
SCI
PORT D
PORT G
PG7:0
(8-bits)
10-BIT ADC
PORT H
PH7:0
(8-bits)
PD7:0
(8-bits)
VAREF
VSSA
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ST72321M6 ST72321M9
2 PIN DESCRIPTION
PA7 (HS) / SCLI
PA6 (HS) / SDAI
PA5 (HS)
PA4 (HS)
TLI
EVD
RESET
VPP / ICCSEL
PH4
PH7
PH6
PH5
OSC2
VSS_2
OSC1
)
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80
79
78
77
76
75
74
73
72
71
70
69
68
67
66
65
64
63
62
61
PE3
PE2
PE1 / RDI
PE0 / TDO
VDD_2
Figure 2. 80-Pin LQFP 14x14 Package Pinout
(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
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
ei0
60
59
58
57
56
55
54
53
52
51
50
49
48
47
46
45
44
43
42
41
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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
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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
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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
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VSS_1
VDD_1
PA3 (HS)
PA2
PA1
PA0
PC7 / SS / AIN15
PC6 / SCK /ICCCLK
(HS) 20 mA high sink capability
eix associated external interrupt vector
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ST72321M6 ST72321M9
PIN DESCRIPTION (Cont’d)
Legend / Abbreviations for Table 2 :
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 0.8 V / 2 V with Schmitt trigger
Output level:
HS = 20 mA 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
The RESET configuration of each pin is shown in bold. This configuration is valid as long as the device is
in reset state.
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Table 2. Device Pin Description
Port
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wpu
PE4 (HS)
I/O CT
HS
X
X
2
PE5 (HS)
HS
X
X
3
PE6 (HS)
I/O CT
I/O CT
HS
X
X
4
PE7 (HS)
HS
X
X
5
PB0/PWM3
I/O CT
I/O CT
6
PB1/PWM2
I/O CT
7
PB2/PWM1
I/O CT
I/O CT
X
I/O TT
I/O TT
X
X
X
X
X
X
X
Port G1
I/O TT
I/O TT
X
X
X
X
Port G2
X
X
X
X
Port G3
Alternate function
PP
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OD
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ana
float
1
Pin Name
int
Output
Input
Main
function
Output
(after
reset)
Input
Type
Level
LQFP80
Pin n°
X
X
Port E4
X
X
Port E5
X
X
Port E6
X
X
Port E7
X
ei2
X
X
Port B0
PWM Output 3
X
ei2
X
X
Port B1
PWM Output 2
X
ei2
X
X
Port B2
PWM Output 1
X
Port B3
PWM Output 0
X
Port G0
8
PB3/PWM0
9
PG0
10
PG1
11
PG2
12
PG3
13
PB4 (HS)/ARTCLK
I/O CT
X
ei3
X
X
Port B4
PWM-ART External Clock
PB5/ARTIC1
I/O CT
I/O CT
X
ei3
X
X
Port B5
PWM-ART Input Capture 1
X
ei3
X
X
Port B6
PWM-ART Input Capture 2
I/O CT
I/O CT
X
X
X
Port B7
X
X
X
X
X
Port D0
ADC Analog Input 0
I/O CT
I/O CT
X
X
X
X
X
Port D1
ADC Analog Input 1
X
X
X
X
X
Port D2
ADC Analog Input 2
X
X
X
X
X
Port D3
ADC Analog Input 3
X
X
X
X
Port G6
14
15
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PB6/ARTIC2
HS
X
ei2
16
PB7
17
PD0 /AIN0
18
PD1/AIN1
19
PD2/AIN2
20
PD3/AIN3
21
PG6
I/O CT
I/O TT
22
PG7
I/O TT
X
X
X
X
Port G7
23
PD4/AIN4
X
X
X
X
X
Port D4
ADC Analog Input 4
24
PD5/AIN5
I/O CT
I/O CT
X
X
X
X
X
Port D5
ADC Analog Input 5
25
PD6/AIN6
I/O CT
X
X
X
X
X
Port D6
ADC Analog Input 6
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ST72321M6 ST72321M9
2)
X
X
PP
X
Main
function
Output
(after
reset)
OD
I/O CT
I
int
Output
Input
wpu
PD7/AIN7
Port
float
26
Input
Pin Name
Type
LQFP80
Level
ana
Pin n°
X
X
Port D7
Alternate function
ADC Analog Input 7
27
VAREF
28
VSSA 2)
S
Analog Ground Voltage
29
VDD_3 2)
S
Digital Main Supply Voltage
30
VSS_3 2)
S
Digital Ground Voltage
31
PG4
I/O TT
X
X
X
X
Port G4
32
PG5
I/O TT
X
X
X
X
Port G5
33
PF0/MCO/AIN8
I/O CT
X
ei1
X
X
Port F0
Main clock
out (fCPU)
34
PF1 (HS)/BEEP
I/O CT
HS
X
ei1
X
X
Port F1
Beep signal output
35
PF2 (HS)
I/O CT
HS
X
X
X
Port F2
Analog Reference Voltage for ADC
X
ei1
36
PF3/OCMP2_A/AIN9
I/O CT
X
X
X
37
PF4/OCMP1_A/AIN10
I/O CT
X
X
X
38
PF5/ICAP2_A/AIN11
I/O CT
X
X
X
39
PF6 (HS)/ICAP1_A
I/O CT
40
PF7 (HS)/EXTCLK_A
I/O CT
41
VDD_0 2)
S
42
VSS_0 2)
S
43
PC0/OCMP2_B/AIN12
44
HS
ct
HS
X
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Pr
)
(s
X
X
X
X
X
)
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ADC Analog
Input 8
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Timer A OutADC Analog
put Compare
Input 9
2
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Port F3
X
X
Port F4
Timer A OutADC Analog
put Compare
Input 10
1
X
X
Port F5
Timer A Input ADC Analog
Capture 2
Input 11
X
X
Port F6
Timer A Input Capture 1
Port F7
Timer A External Clock
Source
s
b
O
X
X
Digital Main Supply Voltage
Digital Ground Voltage
I/O CT
X
X
X
X
X
Port C0
Timer B OutADC Analog
put Compare
Input 12
2
PC1/OCMP1_B/AIN13
I/O CT
X
X
X
X
X
Port C1
Timer B OutADC Analog
put Compare
Input 13
1
PC2 (HS)/ICAP2_B
I/O CT
HS
X
X
X
X
Port C2
Timer B Input Capture 2
PC3 (HS)/ICAP1_B
I/O CT
HS
X
X
X
X
Port C3
Timer B Input Capture 1
47
PC4/MISO/ICCDATA
I/O CT
X
X
X
X
Port C4
SPI Master In
ICC Data In/ Slave Out
put
Data
48
PC5/MOSI/AIN14
I/O CT
X
X
X
X
Port C5
SPI Master
ADC Analog
Out / Slave In
Input 14
Data
49
PH0
X
X
X
X
Port H0
50
PH1
I/O TT
I/O TT
X
X
X
X
Port H1
51
PH2
X
X
X
X
Port H2
52
PH3
I/O TT
I/O TT
X
X
X
X
Port H3
45
46
e
t
e
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b
O
10/175
X
ST72321M6 ST72321M9
Main
function
Output
(after
reset)
Alternate function
PP
ana
int
float
wpu
Input
Output
Input
Type
LQFP80
Pin Name
Port
OD
Level
Pin n°
SPI Serial
Clock
53
PC6/SCK/ICCCLK
I/O CT
X
X
54
PC7/SS/AIN15
I/O CT
X
X
55
PA0
X
56
PA1
I/O CT
I/O CT
57
PA2
I/O CT
58
PA3 (HS)
I/O CT
S
2)
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
Port A3
X
ei0
59
VDD_1
60
VSS_1 2)
61
PA4 (HS)
I/O CT
HS
X
X
62
PA5 (HS)
X
X
PA6 (HS)/SDAI
I/O CT
I/O CT
HS
63
HS
X
64
PA7 (HS)/SCLI
I/O CT
HS
X
65
VPP/ ICCSEL
66
RESET
67
EVD
68
TLI
69
PH4
70
PH5
71
PH6
72
PH7
73
VSS_2 2)
74
OSC23)
I/O CT
e
t
e
l
SPI Slave
ADC Analog
Select (active
Input 15
low)
)
s
(
ct
u
d
o
r
P
e
t
e
l
o
Digital Ground Voltage
I
I
Caution: Negative current
injection not allowed on this
pin
Digital Main Supply Voltage
S
o
s
b
O
X
ICC Clock
Output
X
X
Port A5
T
Port A6
I2C Data 5)
T
Port A7
I2C Clock 5)
Must be tied low. In Flash programming
mode, this pin acts as the programming
voltage input VPP.
s
(
t
c
u
d
o
Port A4
s
b
O
X
)-
X
Top priority non maskable interrupt.
External voltage detector
CT
X
I/O TT
I/O TT
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
Pr
X
Top level interrupt input pin
S
Digital Ground Voltage
I/O
Resonator oscillator inverter output
OSC13)
I
External clock input or Resonator oscillator inverter input
76
VDD_2 2)
S
Digital Main Supply Voltage
77
PE0/TDO
I/O CT
X
X
X
X
Port E0
SCI Transmit Data Out
78
PE1/RDI
I/O CT
X
X
X
X
Port E1
SCI Receive Data In
79
PE2
80
PE3
I/O CT
I/O CT
75
X
X
X
Port E2
X
X
Port E3
Notes:
1. In the interrupt input column, “eiX” defines the associated external interrupt vector. If the weak pull-up
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. It is mandatory to connect all available VDD and VREF pins to the supply voltage and all VSS and VSSA
11/175
ST72321M6 ST72321M9
pins to ground.
3. OSC1 and OSC2 pins connect a crystal/ceramic resonator, or an external source to the on-chip oscillator.
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.
5. In the open drain output column, “T” defines a true open drain I/O (P-Buffer and protection diode to VDD
are not implemented).
)
s
(
ct
u
d
o
r
P
e
t
e
l
o
)
(s
t
c
u
d
o
r
P
e
t
e
l
o
s
b
O
12/175
s
b
O
ST72321M6 ST72321M9
3 REGISTER & MEMORY MAP
As shown in Figure 3, the MCU is capable of addressing 64 Kbytes of memories and I/O registers.
The available memory locations consist of 128
bytes of register locations, up to 2 Kbytes of RAM
and up to 60 Kbytes 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
)
s
(
ct
Figure 3. Memory Map
0000h
0080h
HW Registers
(see Table 3)
007Fh
0080h
00FFh
0100h
RAM
(2048 or 1024 Bytes)
r
P
e
256 Bytes Stack
t
e
l
o
01FFh
0200h
087Fh
0880h
Reserved
1000h
or 047Fh
or 067Fh
or 087Fh
0FFFh
1000h
Program Memory
(60 Kbytes or 32 Kbytes)
FFDFh
FFE0h
u
d
o
Short Addressing
RAM (zero page)
Interrupt & Reset Vectors
)
(s
t
c
u
FFFFh
16-bit Addressing
RAM
s
b
O
8000h
60 Kbytes
32 Kbytes
FFFFh
d
o
r
P
e
t
e
l
o
s
b
O
13/175
ST72321M6 ST72321M9
Table 3. Hardware Register Map
Register
Label
Reset
Status
Address
Block
0000h
0001h
0002h
Port A 2)
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
2)
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
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
2)
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
Port E
2)
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 2)
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
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
0006h
0007h
0008h
Port B
0009h
000Ah
000Bh
Port C
000Ch
000Dh
000Eh
0018h
0019h
001Ah
001Bh
001Ch
001Dh
001Eh
o
s
b
I 2C
O
I2CCR
I2CSR1
I2CSR2
I2CCCR
I2COAR1
I2COAR2
I2CDR
001Fh
0020h
0021h
0022h
0023h
14/175
O
)
t(s
c
u
d
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
Remarks
let
r
P
e
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
)
s
(
ct
u
d
o
o
s
b
ro
P
e
let
Register Name
ST72321M6 ST72321M9
Address
Register
Label
Block
0024h
0025h
0026h
0027h
ITC
0028h
0029h
Flash
002Ah
WATCHDOG
002Bh
002Ch
002Dh
MCC
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
TIMER A
TACR2
TACR1
TACSR
TAIC1HR
TAIC1LR
TAOC1HR
TAOC1LR
TACHR
TACLR
TAACHR
TAACLR
TAIC2HR
TAIC2LR
TAOC2HR
TAOC2LR
t
e
l
o
bs
0040h
O
TIMER B
bs
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
O
)
s
(
t
c
u
d
o
r
P
e
000x 000x b R/W
00h
00h
)
s
(
ct
u
d
o
r
P
e
t
e
l
o
Reserved Area (3 Bytes)
0031h
0032h
0033h
0034h
0035h
0036h
0037h
0038h
0039h
003Ah
003Bh
003Ch
003Dh
003Eh
003Fh
Remarks
ISPR0
ISPR1
ISPR2
ISPR3
002Eh
to
0030h
0041h
0042h
0043h
0044h
0045h
0046h
0047h
0048h
0049h
004Ah
004Bh
004Ch
004Dh
004Eh
004Fh
Reset
Status
Register Name
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
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)
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
15/175
ST72321M6 ST72321M9
Address
Block
0050h
0051h
0052h
0053h
0054h
0055h
0056h
0057h
SCI
Register
Label
SCISR
SCIDR
SCIBRR
SCICR1
SCICR2
SCIERPR
SCIETPR
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
0058h
to
006Fh
C0h
xxh
00h
x000 0000b
00h
00h
--00h
Remarks
Read Only
R/W
R/W
R/W
R/W
R/W
R/W
)
s
(
ct
Reserved Area (24 Bytes)
0070h
0071h
0072h
ADC
0073h
0074h
0075h
0076h
0077h
0078h
0079h
007Ah
Reset
Status
Register Name
PWM ART
007Bh
007Ch
007Dh
ADCCSR
ADCDRH
ADCDRL
Control/Status Register
Data High Register
Data Low Register
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
o
s
b
e
t
e
ol
Pr
O
)
s
(
t
c
u
d
o
r
P
e
let
u
d
o
007Eh
007Fh
00h
00h
00h
00h
00h
00h
00h
00h
00h
00h
00h
00h
00h
00h
R/W
Read Only
Read Only
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Read Only
Read Only
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.
s
b
O
16/175
ST72321M6 ST72321M9
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.
Depending on the overall Flash memory size in the
microcontroller device, there are up to three user
sectors (see Table 4). 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 4). They are mapped in the upper part
of the ST7 addressing space so the reset and interrupt vectors are located in Sector 0 (F000hFFFFh).
■
■
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
t
c
u
d
o
r
P
e
4.3 Structure
Available Sectors
r
P
e
4
t
e
l
o
s
b
O
Sector 0
8
Sectors 0,1
t
e
l
o
>8
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 is enabled and removed
through the FMP_R bit in the option byte.
Note: The LVD is not supported if read-out protection is enabled.
)
(s
■
u
d
o
Flash Size (Kbytes)
4.2 Main Features
■
)
s
(
ct
Table 4. Sectors available in Flash devices
s
b
O
The Flash memory is organised in sectors and can
be used for both code and data storage.
Figure 4. 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
2 Kbytes
8 Kbytes
16 Kbytes 24 Kbytes 40 Kbytes 52 Kbytes
4 Kbytes
4 Kbytes
SECTOR 1
SECTOR 0
17/175
ST72321M6 ST72321M9
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 5, 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 5).
These pins are:
– RESET: device reset
– VSS: device power supply ground
Figure 5. Typical ICC Interface
PROGRAMMING TOOL
)
s
(
ct
ICC CONNECTOR
ICC Cable
APPLICATION BOARD
9
7
5
3
1
10
8
6
4
2
ST7
u
d
o
r
P
e
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
resistor1 kΩ or
t
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18/175
s
b
O
ICCDATA
VSS
s
(
t
c
)ICCSEL/VPP
OSC1
VDD
OSC2
CL1
ICCCLK
CL2
r
P
e
t
e
l
o
10kΩ
APPLICATION
POWER SUPPLY
u
d
o
ICC CONNECTOR
HE10 CONNECTOR TYPE
OPTIONAL
(See Note 4)
RESET
(See Note 3)
APPLICATION
RESET SOURCE
See Note 2
See Note 1
APPLICATION
I/O
a reset management IC with open drain output and
pull-up resistor>1 kΩ, 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.
ST72321M6 ST72321M9
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 5). For more details on
the pin locations, refer to the device pinout description.
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)
)
s
(
ct
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
t
e
l
o
7
bs
0
0
0
0
0
0
0
0
0
O
)
s
(
t
c
u
d
o
r
P
e
Read/Write
Reset Value: 0000 0000 (00h)
4.6 IAP (In-Application Programming)
u
d
o
This register is reserved for use by Programming
Tool software. It controls the Flash programming
and erasing operations.
Figure 6. Flash Control/Status Register Address and Reset Value
Address
(Hex.)
Register
Label
0029h
FCSR
Reset Value
o
s
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e
t
e
l
O
19/175
Pr
7
0
6
5
4
3
2
1
0
0
0
0
0
0
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ST72321M6 ST72321M9
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 six CPU registers shown in Figure 1 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 7. CPU Registers
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ACCUMULATOR
RESET VALUE = XXh
7
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15
PCH
0
X INDEX REGISTER
RESET VALUE = XXh
7
0
Y INDEX REGISTER
RESET VALUE = XXh
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
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ST72321M6 ST72321M9
CENTRAL PROCESSING UNIT (Cont’d)
Condition Code Register (CC)
Read/Write
Reset Value: 111x1xxx
Bit 1 = Z Zero.
7
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.
0
1
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 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.
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Interrupt Management Bits
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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
(that is, the most significant bit is a logic 1).
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This bit is accessed by the JRMI and JRPL instructions.
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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.
ST72321M6 ST72321M9
CENTRAL PROCESSING UNIT (Cont’d)
Stack Pointer (SP)
Read/Write
Reset Value: 01 FFh
15
8
0
0
0
0
0
0
0
7
1
0
SP7
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 2).
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.
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POP Y
RET
or RSP
IRET
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SP
SP
CC
A
Y
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
Stack Higher Address = 01FFh
Stack Lower Address = 0100h
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PUSH Y
Interrupt
Event
@ 0100h
@ 01FFh
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Figure 8. Stack Manipulation Example
CALL
Subroutine
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 2.
– 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.
SP
SP
ST72321M6 ST72321M9
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 10.
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 146.
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
MULTI-
fOSC
OSC1
(MO)
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MANAGER
(RSM)
/2
1
PLL
(option)
fOSC2
)
(s
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fOSC2
MAIN CLOCK
fCPU
CONTROLLER
WITH REALTIME
CLOCK (MCC/RTC)
SYSTEM INTEGRITY MANAGEMENT
WATCHDOG
AVD Interrupt Request
SICSR
AVD AVD AVD LVD
S IE
F RF
TIMER (WDG)
0
0
0
LOW VOLTAGE
DETECTOR
VDD
(LVD)
0
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VSS
EVD
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PLL OPTION BIT
RESET SEQUENCE
RESET
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OSCILLATOR
PLL x 2
fOSC
Figure 10. Clock, Reset and Supply Block Diagram
OSC2
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Figure 9. PLL Block Diagram
AUXILIARY VOLTAGE
DETECTOR
1
(AVD)
WDG
RF
ST72321M6 ST72321M9
6.2 MULTI-OSCILLATOR (MO)
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 5. 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 (>16 MHz.),
putting the ST7 in an unsafe/undefined state. The
product behaviour must therefore be considered
undefined when the OSC pins are left unconnected.
Hardware Configuration
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ST7
External Clock
Crystal/Ceramic Resonators
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Table 5. ST7 Clock Sources
Internal RC Oscillator
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 13.1 on page 167 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.
OSC1
OSC2
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EXTERNAL
SOURCE
CL1
ST7
OSC1
OSC2
LOAD
CAPACITORS
ST7
OSC1
OSC2
CL2
ST72321M6 ST72321M9
6.3 RESET SEQUENCE MANAGER (RSM)
6.3.1 Introduction
The reset sequence manager includes three RESET sources as shown in Figure 12:
■ 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 11:
■ 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 13.1 on page 167).
Figure 12. Reset Block Diagram
The RESET vector fetch phase duration is 2 clock
cycles.
Figure 11. RESET Sequence Phases
RESET
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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 154 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 13). This detection is asynchronous and therefore the MCU
can enter reset state even in HALT mode.
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FETCH
VECTOR
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VDD
RESET
INTERNAL RESET
256 or 4096 CLOCK CYCLES
Active Phase
RON
INTERNAL
RESET
Filter
PULSE
GENERATOR
WATCHDOG RESET
LVD RESET
ST72321M6 ST72321M9
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 13), the
signal on the RESET pin may be stretched. Otherwise the delay will not be applied (see long ext.
Reset in Figure 13). 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 136)
Figure 13. RESET Sequences
VDD
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RUN
RUN
ACTIVE PHASE
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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 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
ST72321M6 ST72321M9
ON-CHIP PERIPHERALS (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
OPx
Counter > OCRx
1
0
0
1
0
1
)
(s
Note: When an OPx bit is modified, the PWMx output signal polarity is immediately reversed.
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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.
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PWMx output level
Counter parity bit
is 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.
Example: data = 00110101; 4 bits set => parity bit
is 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.
9.6.4.8 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 is “1”, but the
Noise Flag bit is 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 64µs), then the 8th,
9th and 10th samples are at 28µs, 32µs and 36µs
respectively (the first sample starting ideally at
0µs). 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 40µs
(36µs for the 10th sample + 4µs for synchronization with the internal sampling clock).
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ST72321M6 ST72321M9
SERIAL COMMUNICATIONS INTERFACE (Cont’d)
9.6.4.9 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 quantization 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%
9.6.4.10 Noise Error Causes
See also description of Noise error in Section
9.6.4.3.
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.
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Figure 60. Bit Sampling in Reception Mode
RDI LINE
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Sample
clock
sampled values
1
2
3
4
5
6
7
8
9
10
11
12
13
6/16
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7/16
One bit time
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16
ST72321M6 ST72321M9
SERIAL COMMUNICATIONS INTERFACE (Cont’d)
9.6.5 Low Power Modes
9.6.6 Interrupts
The
SCI interrupt events are connected to the
Mode
Description
same
interrupt vector.
No effect on SCI.
These
events generate an interrupt if the correWAIT
SCI interrupts cause the device to exit from
sponding
Enable Control Bit is set and the interWait mode.
rupt
mask
in the CC register is reset (RIM instrucSCI registers are frozen.
tion).
HALT
In Halt mode, the SCI stops transmitting/receiving until Halt mode is exited.
Enable Exit
Event
Control from
Flag
Bit
Wait
Interrupt Event
Transmit Data Register
TDRE
Empty
Transmission ComTC
plete
Received Data Ready
RDRF
to be Read
Overrun Error DetectOR
ed
Idle Line Detected
IDLE
Parity Error
PE
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TIE
Yes
TCIE
Yes
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Yes
No
Yes
No
Yes
Yes
No
No
let
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b
Exit
from
Halt
RIE
ILIE
PIE
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No
No
ST72321M6 ST72321M9
SERIAL COMMUNICATIONS INTERFACE (Cont’d)
9.6.7 Register Description
Note: The IDLE bit is not set again until the RDRF
bit has been set itself (that is, 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 is
lowed by a write to the SCIDR register).
not lost but the shift register is 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 is not transferred to the shift register
This bit is set by hardware when noise is detected
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.
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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
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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
ST72321M6 ST72321M9
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 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
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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 is
selected after the current byte.
0: Even parity
1: Odd parity
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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
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Note: The M bit must not be modified during a data
transfer (both transmission and reception).
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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.
ST72321M6 ST72321M9
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.
wake-up 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.
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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
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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 sends a BREAK word at the end of the
current word.
ST72321M6 ST72321M9
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
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
16
1
0
32
1
0
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 57).
The RDR register provides the parallel interface
between the input shift register and the internal
bus (see Figure 57).
BAUD RATE REGISTER (SCIBRR)
Read/Write
Reset Value: 0000 0000 (00h)
SCT2
SCT1
SCT0
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SCR2
SCR1 SCR0
Bits 7:6 = SCP[1:0] First SCI Prescaler
These 2 prescaling bits allow several standard
clock division ranges:
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PR Prescaling factor
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3
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SCP1
SCP0
0
0
0
1
4
1
0
13
1
1
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0
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.
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SCP0
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RR Dividing factor
7
SCP1
64
128
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1
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
ST72321M6 ST72321M9
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
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.
0
7
ERPR ERPR ERPR ERPR ERPR ERPR ERPR ERPR
7
6
5
4
3
2
1
0
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 59) 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.
ETPR
6
ETPR
5
ETPR
4
ETPR
3
ETPR
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Conditions
Parameter
fCPU
Accuracy vs
Standard
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fRx
~0.16%
Communication frequency 8 MHz
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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 59) 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 20. Baudrate Selection
Symbol
ETPR ETPR
1
0
~0.79%
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
300
1200
2400
4800
9600
10400
19200
38400
Baud
Rate
~300.48
~1201.92
~2403.84
~4807.69
~9615.38
~10416.67
~19230.77
~38461.54
14400 ~14285.71
Unit
Hz
ST72321M6 ST72321M9
SERIAL COMMUNICATION INTERFACE (Cont’d)
Table 21. 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
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ST72321M6 ST72321M9
9.7 I2C BUS INTERFACE (I2C)
9.7.1 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 (400 kHz).
9.7.2 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
9.7.3 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 61.
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Figure 61. I2C BUS Protocol
SDA
ACK
MSB
SCL
1
START
CONDITION
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8
9
STOP
CONDITION
VR02119B
ST72321M6 ST72321M9
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 100 kHz) and Fast I2C
(up to 400 kHz).
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.
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Figure 62. I2C Interface Block Diagram
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DATA REGISTER (DR)
DATA CONTROL
SDA or SDAI
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DATA SHIFT REGISTER
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SCL or SCLI
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COMPARATOR
OWN ADDRESS REGISTER 1 (OAR1)
OWN ADDRESS REGISTER 2 (OAR2)
CLOCK CONTROL
CLOCK CONTROL REGISTER (CCR)
CONTROL REGISTER (CR)
STATUS REGISTER 1 (SR1)
CONTROL LOGIC
STATUS REGISTER 2 (SR2)
INTERRUPT
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ST72321M6 ST72321M9
I2C BUS INTERFACE (Cont’d)
9.7.4 Functional Description
Refer to the CR, SR1 and SR2 registers in Section
9.7.7. 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.
9.7.4.1 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 63
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.
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 63 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 63 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 63 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.
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ST72321M6 ST72321M9
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.
9.7.4.2 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 63 Transfer sequencing EV5).
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 63 Transfer sequencing EV6).
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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).
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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 63 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.
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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 63 Transfer sequencing EV9).
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ST72321M6 ST72321M9
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 63 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
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.
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ST72321M6 ST72321M9
I2C BUS INTERFACE (Cont’d)
Figure 63. 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
)
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7-bit Master receiver:
S
Address
A
EV5
Data1
A
EV6
Data2
A
EV7
EV7
DataN
.....
Address
A
EV5
Data1
A
EV6 EV8
Data2
A
EV8
S Header
A
Address
A
Data1
A
EV1
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S
Header
EV5
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10-bit Master receiver:
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Pr
Address
EV9
Sr
A
A
EV3
Data1
A
EV8
A
Data1
EV6
.... DataN
.
EV7
EV4
A
P
EV3-1
EV4
A
P
EV8
.....
DataN
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.
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P
EV8
DataN
.....
A
A
P
EV2
A
EV6 EV8
Header
EV5
Data1
EV1 EV3
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DataN
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10-bit Slave transmitter:
10-bit Master transmitter
.....
EV2
Sr Header A
.....
EV8
10-bit Slave receiver:
P
EV7
7-bit Master transmitter:
S
NA
A
P
EV7
ST72321M6 ST72321M9
I2C BUS INTERFACE (Cont’d)
9.7.5 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.
9.7.6 Interrupts
Figure 64. Event Flags and Interrupt Generation
ADD10
BTF
ADSL
SB
AF
STOPF
ARLO
BERR
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INTERRUPT
*
* 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
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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).
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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
ST72321M6 ST72321M9
I2C BUS INTERFACE (Cont’d)
9.7.7 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
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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 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.
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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
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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.
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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
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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 64 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 63) is detected.
ST72321M6 ST72321M9
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 63.
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 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.
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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 63). 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
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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)
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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)
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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
ST72321M6 ST72321M9
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
7
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0
0
AF
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STOPF ARLO BERR GCAL
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Bit 7:5 = Reserved. Forced to 0 by hardware.
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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.
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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).
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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.
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I2C STATUS REGISTER 2 (SR2)
Read Only
Reset Value: 0000 0000 (00h)
0
The SCL line is not held low while STOPF=1.
0: No Stop condition detected
1: Stop condition detected
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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
ST72321M6 ST72321M9
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.
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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.
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ST72321M6 ST72321M9
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
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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).
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Bit 0 = Reserved.
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ST72321M6 ST72321M9
I²C BUS INTERFACE (Cont’d)
Table 22. 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
LSB
0
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ST72321M6 ST72321M9
9.8 10-BIT A/D CONVERTER (ADC)
9.8.1 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.
9.8.2 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 65.
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Figure 65. ADC Block Diagram
fCPU
DIV 4
0
DIV 2
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EOC SPEED ADON
0
CH3
4
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ADCCSR
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ANALOG TO DIGITAL
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CH0
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AIN1
AINx
CH1
)
(s
AIN0
ANALOG
MUX
CH2
ADCDRH
D9
CONVERTER
D8
ADCDRL
D7
0
D6
0
D5
0
D4
0
D3
0
D2
0
D1
D0
ST72321M6 ST72321M9
10-BIT A/D CONVERTER (ADC) (Cont’d)
9.8.3 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.
9.8.3.1 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.
9.8.3.2 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 or a write to any bit of the
ADCCSR register resets the EOC bit.
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.
9.8.3.3 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.
9.8.4 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.
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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.
9.8.5 Interrupts
None.
ST72321M6 ST72321M9
10-BIT A/D CONVERTER (ADC) (Cont’d)
9.8.6 Register Description
CONTROL/STATUS REGISTER (ADCCSR)
Read/Write (Except bit 7 read only)
Reset Value: 0000 0000 (00h)
7
Bit 3:0 = CH[3:0] Channel Selection
These bits are set and cleared by software. They
select the analog input to convert.
0
EOC SPEED ADON
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
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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
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*The number of channels is device dependent. Refer to
the device pinout description.
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*
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
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ST72321M6 ST72321M9
10-BIT A/D CONVERTER (Cont’d)
Table 23. 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
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ST72321M6 ST72321M9
10 INSTRUCTION SET
10.1 CPU ADDRESSING MODES
The CPU features 17 different addressing modes
which can be classified in seven 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
so, most of the addressing modes may be subdivided in two submodes 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.
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byte,#5
The CPU Instruction set is designed to minimize
the number of bytes required per instruction: To do
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Table 24. CPU Addressing Mode Overview
Mode
Syntax
Inherent
nop
Immediate
ld A,#$55
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Short
Direct
ld A,$10
Long
Direct
ld A,$1000
No Offset
Direct
Indexed
Short
Direct
Indexed
Long
Direct
Short
Indirect
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Indexed
Pointer Size
(Hex.)
Length
(Bytes)
+0
+1
00..FF
+1
0000..FFFF
+2
ld A,(X)
00..FF
+0
ld A,($10,X)
00..1FE
+1
ld A,($1000,X)
0000..FFFF
+2
ld A,[$10]
00..FF
00..FF
byte
+2
ld A,[$10.w]
0000..FFFF
00..FF
word
+2
od
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Destination
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Pointer
Address
(Hex.)
Long
Indirect
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
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+1
00..FF
byte
+2
+1
00..FF
byte
+2
+2
00..FF
byte
+3
ST72321M6 ST72321M9
INSTRUCTION SET OVERVIEW (Cont’d)
10.1.1 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
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
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10.1.2 Immediate
Immediate instructions have 2 bytes, the first byte
contains the opcode, the second byte contains the
operand value.
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Immediate Instruction
LD
CP
Function
Load
Compare
BCP
Bit Compare
AND, OR, XOR
Logical Operations
ADC, ADD, SUB, SBC
Arithmetic Operations
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10.1.4 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
submodes:
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.
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Increment/Decrement
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INC/DEC
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10.1.3 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.
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10.1.5 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 submodes:
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.
ST72321M6 ST72321M9
INSTRUCTION SET OVERVIEW (Cont’d)
10.1.6 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 submodes:
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 25. Instructions Supporting Direct,
Indexed, Indirect and Indirect Indexed
Addressing Modes
Long and Short
Instructions
Load
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CP
Compare
AND, OR, XOR
Logical Operations
ADC, ADD, SUB, SBC
Arithmetic Additions/Substractions operations
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BCP
Bit Compare
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Short Instructions Only
CLR
INC, DEC
Function
Clear
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
130/175
Available Relative
Direct/Indirect
Instructions
Function
JRxx
Conditional Jump
CALLR
Call Relative
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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.
)
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Function
LD
10.1.7 Relative mode (Direct, Indirect)
This addressing mode is used to modify the PC
register value, by adding an 8-bit signed offset to
it.
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ST72321M6 ST72321M9
INSTRUCTION SET OVERVIEW (Cont’d)
10.2 INSTRUCTION GROUPS
The ST7 family devices use an Instruction Set
consisting of 63 instructions. The instructions may
Load and Transfer
LD
CLR
Stack operation
PUSH
POP
be subdivided into 13 main groups as illustrated in
the following table:
RSP
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
Unconditional Jump or Call
JRA
JRT
JRF
JP
Conditional Branch
JRxx
Interruption management
TRAP
WFI
HALT
IRET
Condition Code Flag modification
SIM
RIM
SCF
RCF
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Using a prebyte
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
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CALL
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CALLR
SLA
NOP
RET
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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.
ST72321M6 ST72321M9
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
BTJT
Jump if bit is true (1)
btjt Byte, #3, Jmp1
M
CALL
Call subroutine
CALLR
Call subroutine relative
CLR
Clear
CP
Arithmetic Compare
tst(Reg - M)
reg
CPL
One Complement
A = FFH-A
reg, M
DEC
Decrement
dec Y
reg, M
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
JRIH
Jump if ext. INT pin = 1
JRIL
Jump if ext. INT pin = 0
(ext. INT pin low)
JRH
Jump if H = 1
H=1?
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jrf *
Pr
(ext. INT pin high)
H=0?
Jump if I1:0 = 11
I1:0 = 11 ?
Jump if I1:0 11
I1:0 11 ?
JRMI
Jump if N = 1 (minus)
N=1?
JRPL
Jump if N = 0 (plus)
N=0?
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JRNM
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 >
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reg, M
Jump if H = 0
JRM
C
reg, M
o
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JRNH
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C
Pr
1
I1
0
1
N
Z
C
N
Z
1
N
Z
N
Z
N
Z
0
H
I0
C
ST72321M6 ST72321M9
INSTRUCTION SET OVERVIEW (Cont’d)
Mnemo
Description
Dst
Src
JRULE
Jump if (C + Z = 1)
Unsigned
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