STMICROELECTRONICS ST72F321M9T6

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
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
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
4.6 IAP (IN-APPLICATION PROGRAMMING) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
4.7 RELATED DOCUMENTATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
4.7.1 Register Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
5 CENTRAL PROCESSING UNIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
5.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
5.2 MAIN FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
5.3 CPU REGISTERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
6 SUPPLY, RESET AND CLOCK MANAGEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
6.1 PHASE LOCKED LOOP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
6.2 MULTI-OSCILLATOR (MO) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
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) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
25
25
26
26
26
27
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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
27
28
30
31
32
32
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
. . . . 41
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) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
43
44
46
48
48
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) . .
48
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49
51
51
51
51
51
53
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) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
53
53
53
53
54
54
54
56
9.3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.3.2 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.3.3 Register Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.4 16-BIT TIMER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
56
57
61
65
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) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
65
65
65
77
77
77
78
84
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) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
84
84
84
88
89
91
91
92
95
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) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
111
111
111
113
117
117
118
124
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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
124
124
125
125
125
126
128
128
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
129
130
130
131
11 ELECTRICAL CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
11.1 PARAMETER CONDITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
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
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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
148
149
150
151
11.8.1 General Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
11.8.2 Output Driving Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152
11.9 CONTROL PIN CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154
11.9.1 Asynchronous RESET Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154
11.9.2 ICCSEL/VPP Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
11.10TIMER PERIPHERAL CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
11.10.1 8-Bit PWM-ART Auto-Reload Timer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
11.10.2 16-Bit Timer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
11.11COMMUNICATION INTERFACE CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . 158
11.11.1 SPI - Serial Peripheral Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158
11.11.2 I2C - Inter IC Control Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160
11.1210-BIT ADC CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
164
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
175
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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
PROGRAM
MEMORY
(32 - 60 Kbytes)
CONTROL
RAM
(1024-2048 Bytes)
LVD
EVD
AVD
OSC1
OSC2
OSC
WATCHDOG
PORT F
PF7:0
(8-bits)
TIMER A
BEEP
ADDRESS AND DATA BUS
MCC/RTC/BEEP
I2C
PORT A
PORT B
PB7:0
(8-bits)
PWM ART
PORT C
PORT E
TIMER B
PE7:0
(8-bits)
PA7:0
(8-bits)
PC7:0
(8-bits)
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
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
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
ei0
ei2
ei3
ei1
60
59
58
57
56
55
54
53
52
51
50
49
48
47
46
45
44
43
42
41
VSS_1
VDD_1
PA3 (HS)
PA2
PA1
PA0
PC7 / SS / AIN15
PC6 / SCK /ICCCLK
PH3
PH2
PH1
PH0
PC5 / MOSI / AIN14
PC4 / MISO / ICCDATA
PC3 (HS) /ICAP1_B
PC2(HS) / ICAP2_B
PC1 / OCMP1_B / AIN13
PC0 / OCMP2_B /AIN12
VSS_0
VDD_0
MCO /AIN8 / PF0
BEEP / (HS) PF1
(HS) PF2
OCMP2_A / AIN9 /PF3
OCMP1_A/AIN10 /PF4
ICAP2_A/ AIN11 /PF5
ICAP1_A / (HS) / PF6
EXTCLK_A / (HS) PF7
PG6
PG7
AIN4/PD4
AIN5 / PD5
AIN6 / PD6
AIN7 / PD7
VAREF
VSSA
VDD3
VSS3
PG4
PG5
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
(HS) PE4
(HS) PE5
(HS) PE6
(HS) PE7
PWM3 / PB0
PWM2 / PB1
PWM1 / PB2
PWM0 / PB3
PG0
PG1
PG2
PG3
ARTCLK / (HS) PB4
ARTIC1 / PB5
ARTIC2 / PB6
PB7
AIN0 / PD0
AIN1 / PD1
AIN2 / PD2
AIN3 / PD3
(HS) 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.
Table 2. Device Pin Description
Port
wpu
OD
PP
PE4 (HS)
I/O CT
HS
X
X
X
X
Port E4
PE5 (HS)
HS
X
X
X
X
Port E5
3
PE6 (HS)
I/O CT
I/O CT
HS
X
X
X
X
Port E6
4
PE7 (HS)
HS
X
X
X
X
Port E7
5
PB0/PWM3
I/O CT
I/O CT
6
PB1/PWM2
7
PB2/PWM1
ana
float
1
2
Pin Name
int
Output
Input
Main
function
Output
(after
reset)
Input
Type
Level
LQFP80
Pin n°
Alternate function
X
ei2
X
X
Port B0
PWM Output 3
I/O CT
X
ei2
X
X
Port B1
PWM Output 2
I/O CT
I/O CT
X
ei2
X
X
Port B2
PWM Output 1
X
X
Port B3
PWM Output 0
I/O TT
I/O TT
X
X
X
X
Port G0
X
X
X
X
Port G1
X
X
X
X
Port G2
X
X
X
X
Port G3
8
PB3/PWM0
9
PG0
10
PG1
11
PG2
12
PG3
I/O TT
I/O TT
13
PB4 (HS)/ARTCLK
I/O CT
X
ei3
X
X
Port B4
PWM-ART External Clock
14
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
X
HS
ei2
15
PB6/ARTIC2
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
ei3
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ST72321M6 ST72321M9
2)
X
PP
X
Main
function
Output
(after
reset)
OD
X
int
Output
Input
I/O CT
I
Input
wpu
PD7/AIN7
Port
float
26
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)
ei1
X
X
Port F1
Beep signal output
X
X
Port F2
Analog Reference Voltage for ADC
X
ADC Analog
Input 8
34
PF1 (HS)/BEEP
I/O CT
HS
X
35
PF2 (HS)
I/O CT
HS
X
36
PF3/OCMP2_A/AIN9
I/O CT
X
X
X
X
X
Port F3
Timer A OutADC Analog
put Compare
Input 9
2
37
PF4/OCMP1_A/AIN10
I/O CT
X
X
X
X
X
Port F4
Timer A OutADC Analog
put Compare
Input 10
1
38
PF5/ICAP2_A/AIN11
I/O CT
X
X
X
X
X
Port F5
Timer A Input ADC Analog
Capture 2
Input 11
39
PF6 (HS)/ICAP1_A
I/O CT
X
X
X
X
Port F6
Timer A Input Capture 1
Port F7
Timer A External Clock
Source
I/O CT
HS
ei1
40
PF7 (HS)/EXTCLK_A
41
VDD_0 2)
S
Digital Main Supply Voltage
42
VSS_0 2)
S
Digital Ground Voltage
43
PC0/OCMP2_B/AIN12
I/O CT
X
X
X
X
X
Port C0
Timer B OutADC Analog
put Compare
Input 12
2
44
PC1/OCMP1_B/AIN13
I/O CT
X
X
X
X
X
Port C1
Timer B OutADC Analog
put Compare
Input 13
1
HS
X
X
X
X
45
PC2 (HS)/ICAP2_B
I/O CT
HS
X
X
X
X
Port C2
Timer B Input Capture 2
46
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
10/175
X
ST72321M6 ST72321M9
Alternate function
PP
ana
int
wpu
Input
Main
function
Output
(after
reset)
OD
Port
float
Output
Type
LQFP80
Pin Name
Input
Level
Pin n°
SPI Serial
Clock
53
PC6/SCK/ICCCLK
I/O CT
X
X
54
PC7/SS/AIN15
I/O CT
X
X
X
X
X
Port C6
X
X
Port C7
55
PA0
I/O CT
X
ei0
X
X
Port A0
56
PA1
X
ei0
X
X
Port A1
57
PA2
I/O CT
I/O CT
X
ei0
X
X
Port A2
58
PA3 (HS)
X
X
Port A3
2)
59
VDD_1
60
VSS_1 2)
I/O CT
S
HS
X
ei0
ICC Clock
Output
Caution: Negative current
injection not allowed on this
pin
SPI Slave
ADC Analog
Select (active
Input 15
low)
Digital Main Supply Voltage
S
Digital Ground Voltage
61
PA4 (HS)
I/O CT
HS
X
X
X
X
62
PA5 (HS)
HS
X
X
X
X
63
PA6 (HS)/SDAI
I/O CT
I/O CT
HS
X
T
Port A6
I2C Data 5)
64
PA7 (HS)/SCLI
I/O CT
HS
X
T
Port A7
I2C Clock 5)
65
VPP/ ICCSEL
66
RESET
67
EVD
68
TLI
69
PH4
70
PH5
71
PH6
72
PH7
73
VSS_2 2)
S
74
OSC23)
I/O
75
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
Port A4
Port A5
Must be tied low. In Flash programming
mode, this pin acts as the programming
voltage input VPP.
I
I/O CT
Top priority non maskable interrupt.
External voltage detector
I
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
X
Top level interrupt input pin
Digital Ground Voltage
Resonator oscillator inverter output
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).
12/175
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
Figure 3. Memory Map
0000h
007Fh
0080h
HW Registers
(see Table 3)
087Fh
0880h
Reserved
0FFFh
1000h
Program Memory
(60 Kbytes or 32 Kbytes)
FFFFh
Short Addressing
RAM (zero page)
00FFh
0100h
RAM
(2048 or 1024 Bytes)
FFDFh
FFE0h
0080h
256 Bytes Stack
01FFh
0200h
or 047Fh
or 067Fh
or 087Fh
1000h
16-bit Addressing
RAM
8000h
60 Kbytes
32 Kbytes
Interrupt & Reset Vectors
FFFFh
13/175
ST72321M6 ST72321M9
Table 3. Hardware Register Map
Register
Label
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
000Ch
000Dh
000Eh
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
I2CCR
I2CSR1
I2CSR2
I2CCCR
I2COAR1
I2COAR2
I2CDR
I2C Control Register
I2C Status Register 1
I2C Status Register 2
I2C Clock Control Register
I2C Own Address Register 1
I2C Own Address Register2
I2C Data Register
0006h
0007h
0008h
0009h
000Ah
000Bh
0018h
0019h
001Ah
001Bh
001Ch
001Dh
001Eh
Port B
Port C
I 2C
001Fh
0020h
0021h
0022h
0023h
14/175
Register Name
Reset
Status
Address
Remarks
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
ST72321M6 ST72321M9
Address
0024h
0025h
0026h
0027h
Block
ITC
0028h
0029h
Flash
002Ah
WATCHDOG
002Bh
002Ch
002Dh
MCC
Register
Label
Remarks
Interrupt Software Priority Register 0
Interrupt Software Priority Register 1
Interrupt Software Priority Register 2
Interrupt Software Priority Register 3
FFh
FFh
FFh
FFh
R/W
R/W
R/W
R/W
EICR
External Interrupt Control Register
00h
R/W
FCSR
Flash Control/Status Register
00h
R/W
WDGCR
Watchdog Control Register
7Fh
R/W
SICSR
System Integrity Control/Status Register
MCCSR
MCCBCR
Main Clock Control / Status Register
Main Clock Controller: Beep Control Register
000x 000x b R/W
00h
00h
R/W
R/W
Reserved Area (3 Bytes)
TIMER A
TACR2
TACR1
TACSR
TAIC1HR
TAIC1LR
TAOC1HR
TAOC1LR
TACHR
TACLR
TAACHR
TAACLR
TAIC2HR
TAIC2LR
TAOC2HR
TAOC2LR
0040h
0041h
0042h
0043h
0044h
0045h
0046h
0047h
0048h
0049h
004Ah
004Bh
004Ch
004Dh
004Eh
004Fh
Reset
Status
ISPR0
ISPR1
ISPR2
ISPR3
002Eh
to
0030h
0031h
0032h
0033h
0034h
0035h
0036h
0037h
0038h
0039h
003Ah
003Bh
003Ch
003Dh
003Eh
003Fh
Register Name
Timer A Control Register 2
Timer A Control Register 1
Timer A Control/Status Register
Timer A Input Capture 1 High Register
Timer A Input Capture 1 Low Register
Timer A Output Compare 1 High Register
Timer A Output Compare 1 Low Register
Timer A Counter High Register
Timer A Counter Low Register
Timer A Alternate Counter High Register
Timer A Alternate Counter Low Register
Timer A Input Capture 2 High Register
Timer A Input Capture 2 Low Register
Timer A Output Compare 2 High Register
Timer A Output Compare 2 Low Register
00h
00h
xxxx x0xx b
xxh
xxh
80h
00h
FFh
FCh
FFh
FCh
xxh
xxh
80h
00h
R/W
R/W
R/W
Read Only
Read Only
R/W
R/W
Read Only
Read Only
Read Only
Read Only
Read Only
Read Only
R/W
R/W
00h
00h
xxxx x0xx b
xxh
xxh
80h
00h
FFh
FCh
FFh
FCh
xxh
xxh
80h
00h
R/W
R/W
R/W
Read Only
Read Only
R/W
R/W
Read Only
Read Only
Read Only
Read Only
Read Only
Read Only
R/W
R/W
Reserved Area (1 Byte)
TIMER B
TBCR2
TBCR1
TBCSR
TBIC1HR
TBIC1LR
TBOC1HR
TBOC1LR
TBCHR
TBCLR
TBACHR
TBACLR
TBIC2HR
TBIC2LR
TBOC2HR
TBOC2LR
Timer B Control Register 2
Timer B Control Register 1
Timer B Control/Status Register
Timer B Input Capture 1 High Register
Timer B Input Capture 1 Low Register
Timer B Output Compare 1 High Register
Timer B Output Compare 1 Low Register
Timer B Counter High Register
Timer B Counter Low Register
Timer B Alternate Counter High Register
Timer B Alternate Counter Low Register
Timer B Input Capture 2 High Register
Timer B Input Capture 2 Low Register
Timer B Output Compare 2 High Register
Timer B Output Compare 2 Low Register
15/175
ST72321M6 ST72321M9
Address
0050h
0051h
0052h
0053h
0054h
0055h
0056h
0057h
Block
SCI
Register
Label
SCISR
SCIDR
SCIBRR
SCICR1
SCICR2
SCIERPR
SCIETPR
0058h
to
006Fh
0070h
0071h
0072h
007Bh
007Ch
007Dh
SCI Status Register
SCI Data Register
SCI Baud Rate Register
SCI Control Register 1
SCI Control Register 2
SCI Extended Receive Prescaler Register
Reserved area
SCI Extended Transmit Prescaler Register
Reset
Status
Remarks
C0h
xxh
00h
x000 0000b
00h
00h
--00h
Read Only
R/W
R/W
R/W
R/W
R/W
R/W
Reserved Area (24 Bytes)
ADC
0073h
0074h
0075h
0076h
0077h
0078h
0079h
007Ah
Register Name
PWM ART
ADCCSR
ADCDRH
ADCDRL
Control/Status Register
Data High Register
Data Low Register
00h
00h
00h
R/W
Read Only
Read Only
PWMDCR3
PWMDCR2
PWMDCR1
PWMDCR0
PWMCR
ARTCSR
ARTCAR
ARTARR
ARTICCSR
ARTICR1
ARTICR2
PWM AR Timer Duty Cycle Register 3
PWM AR Timer Duty Cycle Register 2
PWM AR Timer Duty Cycle Register 1
PWM AR Timer Duty Cycle Register 0
PWM AR Timer Control Register
Auto-Reload Timer Control/Status Register
Auto-Reload Timer Counter Access Register
Auto-Reload Timer Auto-Reload Register
AR Timer Input Capture Control/Status Reg.
AR Timer Input Capture Register 1
AR Timer Input Capture Register 1
00h
00h
00h
00h
00h
00h
00h
00h
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Read Only
Read Only
007Eh
007Fh
00h
00h
00h
Reserved Area (2 Bytes)
Legend: x=undefined, R/W=read/write
Notes:
1. The contents of the I/O port DR registers are readable only in output configuration. In input configuration, the values of the I/O pins are returned instead of the DR register contents.
2. The bits associated with unavailable pins must always keep their reset value.
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).
Table 4. Sectors available in Flash devices
Flash Size (Kbytes)
Available Sectors
4
Sector 0
4.2 Main Features
■
■
■
■
Three Flash programming modes:
– Insertion in a programming tool. In this mode,
all sectors including option bytes can be programmed or erased.
– ICP (In-Circuit Programming). In this mode, all
sectors including option bytes can be programmed or erased without removing the device from the application board.
– IAP (In-Application Programming) In this
mode, all sectors except Sector 0, can be programmed or erased without removing the device from the application board and while the
application is running.
ICT (In-Circuit Testing) for downloading and
executing user application test patterns in RAM
Read-out protection
Register Access Security System (RASS) to
prevent accidental programming or erasing
4.3 Structure
8
Sectors 0,1
>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.
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
ICC CONNECTOR
ICC Cable
APPLICATION BOARD
(See Note 3)
ICC CONNECTOR
HE10 CONNECTOR TYPE
OPTIONAL
(See Note 4)
9
7
5
3
1
10
8
6
4
2
APPLICATION
RESET SOURCE
See Note 2
10kΩ
Notes:
1. If the ICCCLK or ICCDATA pins are only used
as outputs in the application, no signal isolation is
necessary. As soon as the Programming Tool is
plugged to the board, even if an ICC session is not
in progress, the ICCCLK and ICCDATA pins are
not available for the application. If they are used as
inputs by the application, isolation such as a serial
resistor has to implemented in case another device forces the signal. Refer to the Programming
Tool documentation for recommended resistor values.
2. During the ICC session, the programming tool
must control the RESET pin. This can lead to conflicts between the programming tool and the application reset circuit if it drives more than 5mA at
high level (push pull output or pull-up
resistor<1 kΩ). A schottky diode can be used to
isolate the application RESET circuit in this case.
When using a classical RC network with R>1 kΩ or
18/175
ICCDATA
ICCCLK
ST7
RESET
See Note 1
ICCSEL/VPP
OSC1
CL1
OSC2
VDD
CL2
VSS
APPLICATION
POWER SUPPLY
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.
4.6 IAP (In-Application Programming)
This mode uses a BootLoader program previously
stored in Sector 0 by the user (in ICP mode or by
plugging the device in a programming tool).
This mode is fully controlled by user software. This
allows it to be adapted to the user application, (user-defined strategy for entering programming
mode, choice of communications protocol used to
fetch the data to be stored, etc.). For example, it is
possible to download code from the SPI, SCI, USB
or CAN interface and program it in the Flash. IAP
mode can be used to program any of the Flash
sectors except Sector 0, which is write/erase protected to allow recovery in case errors occur during the programming operation.
4.7 Related Documentation
For details on Flash programming and ICC protocol, refer to the ST7 Flash Programming Reference Manual and to the ST7 ICC Protocol Reference Manual.
4.7.1 Register Description
FLASH CONTROL/STATUS REGISTER (FCSR)
Read/Write
Reset Value: 0000 0000 (00h)
7
0
0
0
0
0
0
0
0
0
This register is reserved for use by Programming
Tool software. It controls the Flash programming
and erasing operations.
Figure 6. Flash Control/Status Register Address and Reset Value
Address
(Hex.)
Register
Label
0029h
FCSR
Reset Value
19/175
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
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
7
0
ACCUMULATOR
RESET VALUE = XXh
7
0
X INDEX REGISTER
RESET VALUE = XXh
7
0
Y INDEX REGISTER
RESET VALUE = XXh
15
PCH
8 7
PCL
0
PROGRAM COUNTER
RESET VALUE = RESET VECTOR @ FFFEh-FFFFh
7
0
1 1 I1 H I0 N Z C
CONDITION CODE REGISTER
RESET VALUE = 1 1 1 X 1 X X X
15
8 7
0
STACK POINTER
RESET VALUE = STACK HIGHER ADDRESS
X = Undefined Value
20/175
ST72321M6 ST72321M9
CENTRAL PROCESSING UNIT (Cont’d)
Condition Code Register (CC)
Read/Write
Reset Value: 111x1xxx
Bit 1 = Z Zero.
7
1
0
1
I1
H
I0
N
Z
C
The 8-bit Condition Code register contains the interrupt masks and four flags representative of the
result of the instruction just executed. This register
can also be handled by the PUSH and POP instructions.
These bits can be individually tested and/or controlled by specific instructions.
Arithmetic Management Bits
Bit 4 = H Half carry.
This bit is set by hardware when a carry occurs between bits 3 and 4 of the ALU during an ADD or
ADC instructions. It is reset by hardware during
the same instructions.
0: No half carry has occurred.
1: A half carry has occurred.
This bit is tested using the JRH or JRNH instruction. The H bit is useful in BCD arithmetic subroutines.
Bit 2 = N Negative.
This bit is set and cleared by hardware. It is representative of the result sign of the last arithmetic,
logical or data manipulation. It’s a copy of the result 7th bit.
0: The result of the last operation is positive or null.
1: The result of the last operation is negative
(that is, the most significant bit is a logic 1).
This bit is accessed by the JRMI and JRPL instructions.
21/175
This bit is set and cleared by hardware. This bit indicates that the result of the last arithmetic, logical
or data manipulation is zero.
0: The result of the last operation is different from
zero.
1: The result of the last operation is zero.
This bit is accessed by the JREQ and JRNE test
instructions.
Bit 0 = C Carry/borrow.
This bit is set and cleared by hardware and software. It indicates an overflow or an underflow has
occurred during the last arithmetic operation.
0: No overflow or underflow has occurred.
1: An overflow or underflow has occurred.
This bit is driven by the SCF and RCF instructions
and tested by the JRC and JRNC instructions. It is
also affected by the “bit test and branch”, shift and
rotate instructions.
Interrupt Management Bits
Bit 5,3 = I1, I0 Interrupt
The combination of the I1 and I0 bits gives the current interrupt software priority.
Interrupt Software Priority
Level 0 (main)
Level 1
Level 2
Level 3 (= interrupt disable)
I1
1
0
0
1
I0
0
1
0
1
These two bits are set/cleared by hardware when
entering in interrupt. The loaded value is given by
the corresponding bits in the interrupt software priority registers (IxSPR). They can be also set/
cleared by software with the RIM, SIM, IRET,
HALT, WFI and PUSH/POP instructions.
See the interrupt management chapter for more
details.
ST72321M6 ST72321M9
CENTRAL PROCESSING UNIT (Cont’d)
Stack Pointer (SP)
Read/Write
Reset Value: 01 FFh
15
0
8
0
0
0
0
0
0
7
SP7
1
0
SP6
SP5
SP4
SP3
SP2
SP1
SP0
The Stack Pointer is a 16-bit register which is always pointing to the next free location in the stack.
It is then decremented after data has been pushed
onto the stack and incremented before data is
popped from the stack (see Figure 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.
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.
Figure 8. Stack Manipulation Example
CALL
Subroutine
PUSH Y
Interrupt
Event
POP Y
RET
or RSP
IRET
@ 0100h
SP
SP
CC
A
CC
A
X
X
X
PCH
PCH
PCL
PCL
PCL
PCH
PCH
PCH
PCH
PCH
PCL
PCL
PCL
PCL
PCL
Stack Higher Address = 01FFh
Stack Lower Address = 0100h
22/175
SP
PCH
SP
@ 01FFh
Y
CC
A
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
Figure 9. PLL Block Diagram
PLL x 2
0
/2
1
fOSC
fOSC2
PLL OPTION BIT
Figure 10. Clock, Reset and Supply Block Diagram
OSC2
MULTI-
OSC1
fOSC2
fOSC
OSCILLATOR
(MO)
PLL
(option)
MAIN CLOCK
fCPU
CONTROLLER
WITH REALTIME
CLOCK (MCC/RTC)
SYSTEM INTEGRITY MANAGEMENT
RESET SEQUENCE
RESET
MANAGER
(RSM)
WATCHDOG
AVD Interrupt Request
SICSR
AVD AVD AVD LVD
S IE
F RF
TIMER (WDG)
0
0
0
LOW VOLTAGE
VSS
DETECTOR
VDD
(LVD)
0
EVD
23/175
AUXILIARY VOLTAGE
DETECTOR
1
(AVD)
WDG
RF
ST72321M6 ST72321M9
6.2 MULTI-OSCILLATOR (MO)
24/175
Table 5. ST7 Clock Sources
External Clock
Hardware Configuration
Crystal/Ceramic Resonators
External Clock Source
In this external clock mode, a clock signal (square,
sinus or triangle) with ~50% duty cycle has to drive
the OSC1 pin while the OSC2 pin is tied to ground.
Crystal/Ceramic Oscillators
This family of oscillators has the advantage of producing a very accurate rate on the main clock of
the ST7. The selection within a list of 4 oscillators
with different frequency ranges has to be done by
option byte in order to reduce consumption (refer
to section 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.
Internal RC Oscillator
The main clock of the ST7 can be generated by
three different source types coming from the multioscillator block:
■ an external source
■ 4 crystal or ceramic resonator oscillators
■ an internal high frequency RC oscillator
Each oscillator is optimized for a given frequency
range in terms of consumption and is selectable
through the option byte. The associated hardware
configurations are shown in Table 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.
ST7
OSC1
OSC2
EXTERNAL
SOURCE
ST7
OSC1
CL1
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).
The RESET vector fetch phase duration is 2 clock
cycles.
Figure 11. RESET Sequence Phases
RESET
Active Phase
INTERNAL RESET
256 or 4096 CLOCK CYCLES
FETCH
VECTOR
6.3.2 Asynchronous External RESET pin
The RESET pin is both an input and an open-drain
output with integrated RON weak pull-up resistor.
This pull-up has no fixed value but varies in accordance with the input voltage. It can be pulled
low by external circuitry to reset the device. See
“CONTROL PIN CHARACTERISTICS” on
page 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.
Figure 12. Reset Block Diagram
VDD
RON
RESET
INTERNAL
RESET
Filter
PULSE
GENERATOR
25/175
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)
A proper reset signal for a slow rising VDD supply
can generally be provided by an external RC network connected to the RESET pin.
6.3.4 Internal Low Voltage Detector (LVD)
RESET
Two different RESET sequences caused by the internal LVD circuitry can be distinguished:
■ Power-On RESET
■ Voltage Drop RESET
The device RESET pin acts as an output that is
pulled low when VDD<VIT+ (rising edge) or
VDD<VIT- (falling edge) as shown in Figure 13.
The LVD filters spikes on VDD larger than tg(VDD) to
avoid parasitic resets.
6.3.5 Internal Watchdog RESET
The RESET sequence generated by a internal
Watchdog counter overflow is shown in Figure 13.
Starting from the Watchdog counter underflow, the
device RESET pin acts as an output that is pulled
low during at least tw(RSTL)out.
Figure 13. RESET Sequences
VDD
VIT+(LVD)
VIT-(LVD)
LVD
RESET
RUN
SHORT EXT.
RESET
RUN
ACTIVE PHASE
tw(RSTL)out
th(RSTL)in
LONG EXT.
RESET
RUN
ACTIVE
PHASE
ACTIVE
PHASE
WATCHDOG
RESET
RUN
ACTIVE
PHASE
RUN
tw(RSTL)out
tw(RSTL)out
th(RSTL)in
DELAY
EXTERNAL
RESET
SOURCE
RESET PIN
WATCHDOG
RESET
WATCHDOG UNDERFLOW
INTERNAL RESET (256 or 4096 TCPU)
VECTOR FETCH
26/175
ST72321M6 ST72321M9
6.4 SYSTEM INTEGRITY MANAGEMENT (SI)
The System Integrity Management block contains
the Low Voltage Detector (LVD), and Auxiliary
Voltage Detector (AVD) functions. It is managed
by the SICSR register.
6.4.1 Low Voltage Detector (LVD)
The Low Voltage Detector function (LVD) generates a static reset when the VDD supply voltage is
below a VIT- reference value. This means that it
secures the power-up as well as the power-down
keeping the ST7 in reset.
The VIT- reference value for a voltage drop is lower
than the VIT+ reference value for power-on in order
to avoid a parasitic reset when the MCU starts running and sinks current on the supply (hysteresis).
The LVD Reset circuitry generates a reset when
VDD is below:
– VIT+ when VDD is rising
– VIT- when VDD is falling
The LVD function is illustrated in Figure 14.
The voltage threshold can be configured by option
byte to be low, medium or high.
– under full software control
– in static safe reset
In these conditions, secure operation is always ensured for the application without the need for external reset hardware.
During a Low Voltage Detector Reset, the RESET
pin is held low, thus permitting the MCU to reset
other devices.
Notes:
The LVD allows the device to be used without any
external RESET circuitry.
If the medium or low thresholds are selected, the
detection may occur outside the specified operating voltage range. Below 3.8 V, device operation is
not guaranteed.
The LVD is an optional function which can be selected by option byte.
It is recommended to make sure that the VDD supply voltage rises monotonously when the device is
exiting from Reset, to ensure the application functions properly.
Provided the minimum VDD value (guaranteed for
the oscillator frequency) is above VIT-, the MCU
can only be in two modes:
Figure 14. Low Voltage Detector vs Reset
VDD
Vhys
VIT+
VIT-
RESET
27/175
ST72321M6 ST72321M9
SYSTEM INTEGRITY MANAGEMENT (Cont’d)
6.4.2 Auxiliary Voltage Detector (AVD)
The Voltage Detector function (AVD) is based on
an analog comparison between a VIT-(AVD) and
VIT+(AVD) reference value and the VDD main supply or the external EVD pin voltage level (VEVD).
The VIT- reference value for falling voltage is lower
than the VIT+ reference value for rising voltage in
order to avoid parasitic detection (hysteresis).
The output of the AVD comparator is directly readable by the application software through a realtime status bit (AVDF) in the SICSR register. This
bit is read only.
Caution: The AVD function is active only if the
LVD is enabled through the option byte.
6.4.2.1 Monitoring the VDD Main Supply
This mode is selected by clearing the AVDS bit in
the SICSR register.
The AVD voltage threshold value is relative to the
selected LVD threshold configured by option byte
(see section 13.1 on page 167).
If the AVD interrupt is enabled, an interrupt is generated when the voltage crosses the VIT+(AVD) or
VIT-(AVD) threshold (AVDF bit toggles).
In the case of a drop in voltage, the AVD interrupt
acts as an early warning, allowing software to shut
down safely before the LVD resets the microcontroller. See Figure 15.
The interrupt on the rising edge is used to inform
the application that the VDD warning state is over.
If the voltage rise time trv is less than 256 or 4096
CPU cycles (depending on the reset delay selected by option byte), no AVD interrupt will be generated when VIT+(AVD) is reached.
If trv is greater than 256 or 4096 cycles then:
– If the AVD interrupt is enabled before the
VIT+(AVD) threshold is reached, then 2 AVD interrupts will be received: the first when the AVDIE
bit is set, and the second when the threshold is
reached.
– If the AVD interrupt is enabled after the VIT+(AVD)
threshold is reached then only one AVD interrupt
will occur.
Figure 15. Using the AVD to Monitor VDD (AVDS bit=0)
VDD
Early Warning Interrupt
(Power has dropped, MCU not
not yet in reset)
Vhyst
VIT+(AVD)
VIT-(AVD)
VIT+(LVD)
VIT-(LVD)
AVDF bit
trv VOLTAGE RISE TIME
0
1
RESET VALUE
1
0
AVD INTERRUPT
REQUEST
IF AVDIE bit = 1
INTERRUPT PROCESS
LVD RESET
28/175
INTERRUPT PROCESS
ST72321M6 ST72321M9
SYSTEM INTEGRITY MANAGEMENT (Cont’d)
6.4.2.2 Monitoring a Voltage on the EVD pin
This mode is selected by setting the AVDS bit in
the SICSR register.
The AVD circuitry can generate an interrupt when
the AVDIE bit of the SICSR register is set. This interrupt is generated on the rising and falling edges
of the comparator output. This means it is generated when either one of these two events occur:
– VEVD rises up to VIT+(EVD)
– VEVD falls down to VIT-(EVD)
The EVD function is illustrated in Figure 16.
For more details, refer to the Electrical Characteristics section.
Figure 16. Using the Voltage Detector to Monitor the EVD pin (AVDS bit=1)
VEVD
Vhyst
VIT+(EVD)
VIT-(EVD)
AVDF
0
1
0
AVD INTERRUPT
REQUEST
IF AVDIE = 1
INTERRUPT PROCESS
29/175
INTERRUPT PROCESS
ST72321M6 ST72321M9
SYSTEM INTEGRITY MANAGEMENT (Cont’d)
6.4.3 Low Power Modes
Mode
WAIT
HALT
set and the interrupt mask in the CC register is reset (RIM instruction).
Description
No effect on SI. AVD interrupts cause the
device to exit from Wait mode.
The CRSR register is frozen.
Interrupt Event
AVD event
6.4.3.1 Interrupts
The AVD interrupt event generates an interrupt if
the corresponding Enable Control Bit (AVDIE) is
30/175
Enable
Event
Control
Flag
Bit
Exit
from
Wait
Exit
from
Halt
AVDF
Yes
No
AVDIE
ST72321M6 ST72321M9
SYSTEM INTEGRITY MANAGEMENT (Cont’d)
6.4.4 Register Description
SYSTEM INTEGRITY (SI) CONTROL/STATUS REGISTER (SICSR)
Read/Write
set) and cleared by software (writing zero). See
WDGRF flag description for more details. When
Reset Value: 000x 000x (00h)
the LVD is disabled by OPTION BYTE, the LVDRF
bit value is undefined.
7
0
AVD
S
AVD
IE
AVD
F
LVD
RF
0
0
0
WDG
RF
Bit 7 = AVDS Voltage Detection selection
This bit is set and cleared by software. Voltage Detection is available only if the LVD is enabled by
option byte.
0: Voltage detection on VDD supply
1: Voltage detection on EVD pin
Bit 6 = AVDIE Voltage Detector interrupt enable
This bit is set and cleared by software. It enables
an interrupt to be generated when the AVDF flag
changes (toggles). The pending interrupt information is automatically cleared when software enters
the AVD interrupt routine.
0: AVD interrupt disabled
1: AVD interrupt enabled
Bit 5 = AVDF Voltage Detector flag
This read-only bit is set and cleared by hardware.
If the AVDIE bit is set, an interrupt request is generated when the AVDF bit changes value. Refer to
Figure 15 and to Section 6.4.2.1 for additional details.
0: VDD or VEVD over VIT+(AVD) threshold
1: VDD or VEVD under VIT-(AVD) threshold
Bit 4 = LVDRF LVD reset flag
This bit indicates that the last Reset was generated by the LVD block. It is set by hardware (LVD re-
31/175
Bits 3:1 = Reserved, must be kept cleared.
Bit 0 = WDGRF Watchdog reset flag
This bit indicates that the last Reset was generated by the Watchdog peripheral. It is set by hardware (watchdog reset) and cleared by software
(writing zero) or an LVD Reset (to ensure a stable
cleared state of the WDGRF flag when CPU
starts).
Combined with the LVDRF flag information, the
flag description is given by the following table.
RESET Sources
LVDRF
WDGRF
External RESET pin
Watchdog
LVD
0
0
1
0
1
X
Application notes
The LVDRF flag is not cleared when another RESET type occurs (external or watchdog), the
LVDRF flag remains set to keep trace of the original failure.
In this case, a watchdog reset can be detected by
software while an external reset can not.
CAUTION: When the LVD is not activated with the
associated option byte, the WDGRF flag can not
be used in the application.
ST72321M6 ST72321M9
7 INTERRUPTS
7.1 INTRODUCTION
The ST7 enhanced interrupt management provides the following features:
■ Hardware interrupts
■ Software interrupt (TRAP)
■ Nested or concurrent interrupt management
with flexible interrupt priority and level
management:
– Up to 4 software programmable nesting levels
– Up to 16 interrupt vectors fixed by hardware
– 2 non maskable events: RESET, TRAP
– 1 maskable Top Level event: TLI
This interrupt management is based on:
– Bit 5 and bit 3 of the CPU CC register (I1:0),
– Interrupt software priority registers (ISPRx),
– Fixed interrupt vector addresses located at the
high addresses of the memory map (FFE0h to
FFFFh) sorted by hardware priority order.
This enhanced interrupt controller guarantees full
upward compatibility with the standard (not nested) ST7 interrupt controller.
each interrupt vector (see Table 6). The processing flow is shown in Figure 17
When an interrupt request has to be serviced:
– Normal processing is suspended at the end of
the current instruction execution.
– The PC, X, A and CC registers are saved onto
the stack.
– I1 and I0 bits of CC register are set according to
the corresponding values in the ISPRx registers
of the serviced interrupt vector.
– The PC is then loaded with the interrupt vector of
the interrupt to service and the first instruction of
the interrupt service routine is fetched (refer to
“Interrupt Mapping” table for vector addresses).
The interrupt service routine should end with the
IRET instruction which causes the contents of the
saved registers to be recovered from the stack.
Note: As a consequence of the IRET instruction,
the I1 and I0 bits will be restored from the stack
and the program in the previous level will resume.
Table 6. Interrupt Software Priority Levels
Interrupt software priority
Level 0 (main)
Level 1
Level 2
Level 3 (= interrupt disable)
7.2 MASKING AND PROCESSING FLOW
The interrupt masking is managed by the I1 and I0
bits of the CC register and the ISPRx registers
which give the interrupt software priority level of
Level
Low
I1
1
0
0
1
High
I0
0
1
0
1
Figure 17. Interrupt Processing Flowchart
FETCH NEXT
INSTRUCTION
“IRET”
N
RESTORE PC, X, A, CC
FROM STACK
TRAP
Interrupt has the same or a
lower software priority
than current one
N
Y
Y
EXECUTE
INSTRUCTION
THE INTERRUPT
STAYS PENDING
N
I1:0
STACK PC, X, A, CC
LOAD I1:0 FROM INTERRUPT SW REG.
LOAD PC FROM INTERRUPT VECTOR
32/175
Y
Interrupt has a higher
software priority
than current one
PENDING
INTERRUPT
RESET
ST72321M6 ST72321M9
INTERRUPTS (Cont’d)
Servicing Pending Interrupts
As several interrupts can be pending at the same
time, the interrupt to be taken into account is determined by the following two-step process:
– the highest software priority interrupt is serviced,
– if several interrupts have the same software priority then the interrupt with the highest hardware
priority is serviced first.
Figure 18 describes this decision process.
Figure 18. Priority Decision Process
PENDING
INTERRUPTS
Same
SOFTWARE
PRIORITY
Different
HIGHEST SOFTWARE
PRIORITY SERVICED
HIGHEST HARDWARE
PRIORITY SERVICED
When an interrupt request is not serviced immediately, it is latched and then processed when its
software priority combined with the hardware priority becomes the highest one.
Note 1: The hardware priority is exclusive while
the software one is not. This allows the previous
process to succeed with only one interrupt.
Note 2: TLI, RESET and TRAP can be considered
as having the highest software priority in the decision process.
Different Interrupt Vector Sources
Two interrupt source types are managed by the
ST7 interrupt controller: the non-maskable type
(RESET, TRAP) and the maskable type (external
or from internal peripherals).
Non-Maskable Sources
These sources are processed regardless of the
state of the I1 and I0 bits of the CC register (see
Figure 17). After stacking the PC, X, A and CC
registers (except for RESET), the corresponding
vector is loaded in the PC register and the I1 and
I0 bits of the CC are set to disable interrupts (level
3). These sources allow the processor to exit
HALT mode.
33/175
TRAP (Non Maskable Software Interrupt)
This software interrupt is serviced when the TRAP
instruction is executed. It will be serviced according to the flowchart in Figure 17.
Caution: TRAP can be interrupted by a TLI.
■ RESET
The RESET source has the highest priority in the
ST7. This means that the first current routine has
the highest software priority (level 3) and the highest hardware priority.
See the RESET chapter for more details.
■
Maskable Sources
Maskable interrupt vector sources can be serviced
if the corresponding interrupt is enabled and if its
own interrupt software priority (in ISPRx registers)
is higher than the one currently being serviced (I1
and I0 in CC register). If any of these two conditions is false, the interrupt is latched and thus remains pending.
■ TLI (Top Level Hardware Interrupt)
This hardware interrupt occurs when a specific
edge is detected on the dedicated TLI pin. It will be
serviced according to the flowchart in Figure 17 as
a trap.
Caution: A TRAP instruction must not be used in a
TLI service routine.
■ External Interrupts
External interrupts allow the processor to exit from
HALT low power mode. External interrupt sensitivity is software selectable through the External Interrupt Control register (EICR).
External interrupt triggered on edge will be latched
and the interrupt request automatically cleared
upon entering the interrupt service routine.
If several input pins of a group connected to the
same interrupt line are selected simultaneously,
these will be logically ORed.
■ Peripheral Interrupts
Usually the peripheral interrupts cause the MCU to
exit from HALT mode except those mentioned in
the “Interrupt Mapping” table. A peripheral interrupt occurs when a specific flag is set in the peripheral status registers and if the corresponding
enable bit is set in the peripheral control register.
The general sequence for clearing an interrupt is
based on an access to the status register followed
by a read or write to an associated register.
Note: The clearing sequence resets the internal
latch. A pending interrupt (i.e. waiting for being
serviced) will therefore be lost if the clear sequence is executed.
ST72321M6 ST72321M9
INTERRUPTS (Cont’d)
7.3 INTERRUPTS AND LOW POWER MODES
7.4 CONCURRENT & NESTED MANAGEMENT
All interrupts allow the processor to exit the WAIT
low power mode. On the contrary, only external
and other specified interrupts allow the processor
to exit from the HALT modes (see column “Exit
from HALT” in “Interrupt Mapping” table). When
several pending interrupts are present while exiting HALT mode, the first one serviced can only be
an interrupt with exit from HALT mode capability
and it is selected through the same decision process shown in Figure 18.
Note: If an interrupt, that is not able to Exit from
HALT mode, is pending with the highest priority
when exiting HALT mode, this interrupt is serviced
after the first one serviced.
The following Figure 19 and Figure 20 show two
different interrupt management modes. The first is
called concurrent mode and does not allow an interrupt to be interrupted, unlike the nested mode in
Figure 20. The interrupt hardware priority is given
in this order from the lowest to the highest: MAIN,
IT4, IT3, IT2, IT1, IT0, TLI. The software priority is
given for each interrupt.
Warning: A stack overflow may occur without notifying the software of the failure.
IT0
TRAP
IT3
IT4
IT1
SOFTWARE
PRIORITY
LEVEL
TRAP
IT0
IT1
IT1
IT2
IT3
RIM
IT4
MAIN
MAIN
11 / 10
I1
I0
3
1 1
3
1 1
3
1 1
3
1 1
3
1 1
3
1 1
USED STACK = 10 BYTES
HARDWARE PRIORITY
IT2
Figure 19. Concurrent Interrupt Management
3/0
10
IT0
TRAP
IT3
IT4
IT1
TRAP
IT0
IT1
IT1
IT2
IT2
IT3
RIM
IT4
MAIN
11 / 10
34/175
SOFTWARE
PRIORITY
LEVEL
IT4
MAIN
10
I1
I0
3
1 1
3
1 1
2
0 0
1
0 1
3
1 1
3
1 1
3/0
USED STACK = 20 BYTES
HARDWARE PRIORITY
IT2
Figure 20. Nested Interrupt Management
ST72321M6 ST72321M9
INTERRUPTS (Cont’d)
INTERRUPT SOFTWARE PRIORITY REGISTERS (ISPRX)
Read/Write (bit 7:4 of ISPR3 are read only)
Reset Value: 1111 1111 (FFh)
7.5 INTERRUPT REGISTER DESCRIPTION
CPU CC REGISTER INTERRUPT BITS
Read/Write
Reset Value: 111x 1010 (xAh)
7
1
7
0
1
I1
H
I0
N
Z
Level
Low
High
I1
1
0
0
1
I0
0
1
0
1
These two bits are set/cleared by hardware when
entering in interrupt. The loaded value is given by
the corresponding bits in the interrupt software priority registers (ISPRx).
They can be also set/cleared by software with the
RIM, SIM, HALT, WFI, IRET and PUSH/POP instructions (see “Interrupt Dedicated Instruction
Set” table).
*Note: TLI, TRAP and RESET events can interrupt
a level 3 program.
35/175
ISPR0
I1_3
I0_3
I1_2
I0_2
I1_1
I0_1
I1_0
I0_0
ISPR1
I1_7
I0_7
I1_6
I0_6
I1_5
I0_5
I1_4
I0_4
ISPR2
I1_11 I0_11 I1_10 I0_10 I1_9
I0_9
I1_8
I0_8
C
Bit 5, 3 = I1, I0 Software Interrupt Priority
These two bits indicate the current interrupt software priority.
Interrupt Software Priority
Level 0 (main)
Level 1
Level 2
Level 3 (= interrupt disable*)
0
ISPR3
1
1
1
1
I1_13 I0_13 I1_12 I0_12
These four registers contain the interrupt software
priority of each interrupt vector.
– Each interrupt vector (except RESET and TRAP)
has corresponding bits in these registers where
its own software priority is stored. This correspondance is shown in the following table.
Vector address
ISPRx bits
FFFBh-FFFAh
FFF9h-FFF8h
...
FFE1h-FFE0h
I1_0 and I0_0 bits*
I1_1 and I0_1 bits
...
I1_13 and I0_13 bits
– Each I1_x and I0_x bit value in the ISPRx registers has the same meaning as the I1 and I0 bits
in the CC register.
– Level 0 can not be written (I1_x=1, I0_x=0). In
this case, the previously stored value is kept. (example: previous=CFh, write=64h, result=44h)
The TLI, RESET, and TRAP vectors have no software priorities. When one is serviced, the I1 and I0
bits of the CC register are both set.
*Note: Bits in the ISPRx registers which correspond to the TLI can be read and written but they
are not significant in the interrupt process management.
Caution: If the I1_x and I0_x bits are modified
while the interrupt x is executed the following behaviour has to be considered: If the interrupt x is
still pending (new interrupt or flag not cleared) and
the new software priority is higher than the previous one, the interrupt x is re-entered. Otherwise,
the software priority stays unchanged up to the
next interrupt request (after the IRET of the interrupt x).
ST72321M6 ST72321M9
INTERRUPTS (Cont’d)
Table 7. Dedicated Interrupt Instruction Set
Instruction
HALT
New Description
Function/Example
Entering Halt mode
I1
H
1
I0
N
Z
C
0
IRET
Interrupt routine return
Pop CC, A, X, PC
JRM
Jump if I1:0=11 (level 3)
I1:0=11 ?
I1
H
I0
N
Z
C
JRNM
Jump if I1:0<>11
I1:0<>11 ?
POP CC
Pop CC from the Stack
RIM
Enable interrupt (level 0 set)
Mem => CC
I1
H
I0
N
Z
C
Load 10 in I1:0 of CC
1
SIM
Disable interrupt (level 3 set)
Load 11 in I1:0 of CC
1
1
TRAP
Software trap
Software NMI
1
1
WFI
Wait for interrupt
1
0
0
Note: During the execution of an interrupt routine, the HALT, POPCC, RIM, SIM and WFI instructions change the current
software priority up to the next IRET instruction or one of the previously mentioned instructions.
36/175
ST72321M6 ST72321M9
INTERRUPTS (Cont’d)
Table 8. Interrupt Mapping
N°
Source
Block
RESET
TRAP
0
TLI
Register
Label
Description
Reset
N/A
Software interrupt
External top level interrupt
1
MCC/RTC
2
ei0
3
ei1
External interrupt port F2..0
4
ei2
External interrupt port B3..0
5
ei3
External interrupt port B7..4
7
SPI
SPI peripheral interrupts
8
TIMER A
9
TIMER B
Exit
from
Priority
HALT/
Order
Activehalt3)
EICR
Main clock controller time base interrupt
MCCSR
External interrupt port A3..0
Higher
Priority
yes
FFFEh-FFFFh
no
FFFCh-FFFDh
yes
FFFAh-FFFBh
yes
FFF8h-FFF9h
yes
FFF6h-FFF7h
yes
FFF4h-FFF5h
yes
FFF2h-FFF3h
yes
FFF0h-FFF1h
SPICSR
yes1
FFECh-FFEDh
TIMER A peripheral interrupts
TASR
no
FFEAh-FFEBh
TIMER B peripheral interrupts
TBSR
no
FFE8h-FFE9h
no
FFE6h-FFE7h
no
FFE4h-FFE5h
(see periph)
no
FFE2h-FFE3h
ARTCSR
yes2
FFE0h-FFE1h
6
N/A
Not used
FFEEh-FFEFh
10
SCI
SCI Peripheral interrupts
SCISR
11
AVD
Auxiliary Voltage detector interrupt
SICSR
12
I2C
13
PWM ART
Address
Vector
I2C Peripheral interrupts
PWM ART interrupt
Lower
Priority
Notes:
1. Exit from HALT possible when SPI is in slave mode.
2. Exit from HALT possible when PWM ART is in external clock mode.
3. In Flash devices only a RESET or MCC/RTC interrupt can be used to wake-up from Active-halt mode.
7.6 EXTERNAL INTERRUPTS
7.6.1 I/O Port Interrupt Sensitivity
The external interrupt sensitivity is controlled by
the IPA, IPB and ISxx bits of the EICR register
(Figure 21). This control allows to have up to 4 fully
independent external interrupt source sensitivities.
Each external interrupt source can be generated
on four (or five) different events on the pin:
■ Falling edge
■ Rising edge
■ Falling and rising edge
37/175
Falling edge and low level
Rising edge and high level (only for ei0 and ei2)
To guarantee correct functionality, the sensitivity
bits in the EICR register can be modified only
when the I1 and I0 bits of the CC register are both
set to 1 (level 3). This means that interrupts must
be disabled before changing sensitivity.
The pending interrupts are cleared by writing a different value in the ISx[1:0], IPA or IPB bits of the
EICR.
■
■
ST72321M6 ST72321M9
INTERRUPTS (Cont’d)
Figure 21. External Interrupt Control bits
PORT A [3:0] INTERRUPTS
PAOR.3
PADDR.3
EICR
IS20
IS21
SENSITIVITY
PA3
CONTROL
IPA BIT
PORT F [2:0] INTERRUPTS
IS21
SENSITIVITY
PF2
CONTROL
PORT B [3:0] INTERRUPTS
PBOR.3
PBDDR.3
IS10
SENSITIVITY
IPB BIT
PB7
38/175
ei1 INTERRUPT SOURCE
IS11
CONTROL
PBOR.7
PBDDR.7
PF2
PF1
PF0
EICR
PB3
PORT B [7:4] INTERRUPTS
ei0 INTERRUPT SOURCE
EICR
IS20
PFOR.2
PFDDR.2
PA3
PA2
PA1
PA0
PB3
PB2
PB1
PB0
ei2 INTERRUPT SOURCE
EICR
IS10
IS11
SENSITIVITY
CONTROL
PB7
PB6
PB5
PB4
ei3 INTERRUPT SOURCE
ST72321M6 ST72321M9
7.7 EXTERNAL INTERRUPT CONTROL REGISTER (EICR)
Read/Write
Reset Value: 0000 0000 (00h)
- ei0 (port A3..0)
External Interrupt Sensitivity
7
IS11
0
IS10
IPB
IS21
IS20
IPA
TLIS
TLIE
Bit 7:6 = IS1[1:0] ei2 and ei3 sensitivity
The interrupt sensitivity, defined using the IS1[1:0]
bits, is applied to the following external interrupts:
- ei2 (port B3..0)
External Interrupt Sensitivity
IS11 IS10
IPB bit =0
IPB bit =1
Rising edge
& high level
0
0
Falling edge &
low level
0
1
Rising edge only
Falling edge only
1
0
Falling edge only
Rising edge only
1
1
Rising and falling edge
IPA bit =1
Falling edge &
low level
Rising edge
& high level
0
0
0
1
Rising edge only
Falling edge only
1
0
Falling edge only
Rising edge only
1
1
Rising and falling edge
- ei1 (port F2..0)
IS21 IS20
External Interrupt Sensitivity
0
0
Falling edge & low level
0
1
Rising edge only
1
0
Falling edge only
1
1
Rising and falling edge
External Interrupt Sensitivity
0
0
0
1
Rising edge only
1
0
Falling edge only
1
1
Rising and falling edge
Falling edge & low level
These 2 bits can be written only when I1 and I0 of
the CC register are both set to 1 (level 3).
Bit 5 = IPB Interrupt polarity for port B
This bit is used to invert the sensitivity of the port B
[3:0] external interrupts. It can be set and cleared
by software only when I1 and I0 of the CC register
are both set to 1 (level 3).
0: No sensitivity inversion
1: Sensitivity inversion
Bit 4:3 = IS2[1:0] ei0 and ei1 sensitivity
The interrupt sensitivity, defined using the IS2[1:0]
bits, is applied to the following external interrupts:
39/175
IPA bit =0
These 2 bits can be written only when I1 and I0 of
the CC register are both set to 1 (level 3).
- ei3 (port B7..4)
IS11 IS10
IS21 IS20
Bit 2 = IPA Interrupt polarity for port A
This bit is used to invert the sensitivity of the port A
[3:0] external interrupts. It can be set and cleared
by software only when I1 and I0 of the CC register
are both set to 1 (level 3).
0: No sensitivity inversion
1: Sensitivity inversion
Bit 1 = TLIS TLI sensitivity
This bit allows to toggle the TLI edge sensitivity. It
can be set and cleared by software only when
TLIE bit is cleared.
0: Falling edge
1: Rising edge
Bit 0 = TLIE TLI enable
This bit allows to enable or disable the TLI capability on the dedicated pin. It is set and cleared by
software.
0: TLI disabled
1: TLI enabled
Note: a parasitic interrupt can be generated when
clearing the TLIE bit.
ST72321M6 ST72321M9
INTERRUPTS (Cont’d)
Table 9. Nested Interrupts Register Map and Reset Values
Address
(Hex.)
Register
Label
7
0024h
ISPR0
Reset Value
I1_3
1
6
5
I0_3
1
I1_2
1
ei1
4
3
I0_2
1
I1_1
1
ei0
ISPR1
Reset Value
I1_7
1
0026h
ISPR2
Reset Value
0027h
ISPR3
Reset Value
EICR
Reset Value
I0_7
1
I1_6
1
I1_11
1
I0_11
1
I1_10
1
I0_10
1
1
IS11
0
1
IS10
0
1
IPB
0
1
IS21
0
AVD
0028h
40/175
1
MCC
SPI
0025h
2
I0_6
1
SCI
0
TLI
I0_1
1
1
1
ei3
ei2
I1_5
I0_5
1
1
TIMER B
I1_9
I0_9
1
1
PWMART
I1_13
I0_13
1
1
IS20
IPA
0
0
I1_4
I0_4
1
1
TIMER A
I1_8
I0_8
1
1
I2C
I1_12
I0_12
1
1
TLIS
TLIE
0
0
ST72321M6 ST72321M9
8 POWER SAVING MODES
8.1 INTRODUCTION
8.2 SLOW MODE
To give a large measure of flexibility to the application in terms of power consumption, four main
power saving modes are implemented in the ST7
(see Figure 22): Slow, Wait (Slow wait), Active-halt
and Halt.
After a RESET the normal operating mode is selected by default (RUN mode). This mode drives
the device (CPU and embedded peripherals) by
means of a master clock which is based on the
main oscillator frequency divided or multiplied by 2
(fOSC2).
From RUN mode, the different power saving
modes may be selected by setting the relevant
register bits or by calling the specific ST7 software
instruction whose action depends on the oscillator
status.
This mode has two targets:
– To reduce power consumption by decreasing the
internal clock in the device,
– To adapt the internal clock frequency (fCPU) to
the available supply voltage.
Slow mode is controlled by three bits in the MCCSR register: the SMS bit which enables or disables
Slow mode and two CPx bits which select the internal slow frequency (fCPU).
In this mode, the master clock frequency (fOSC2)
can be divided by 2, 4, 8 or 16. The CPU and peripherals are clocked at this lower frequency
(fCPU).
Note: Slow-wait mode is activated when entering
the WAIT mode while the device is already in Slow
mode.
Figure 22. Power Saving Mode Transitions
Figure 23. Slow Mode Clock Transitions
High
fOSC2/2
fOSC2/4
fOSC2
MCCSR
SLOW
WAIT
CP1:0
00
01
SMS
SLOW WAIT
NEW SLOW
FREQUENCY
REQUEST
ACTIVE HALT
HALT
Low
POWER CONSUMPTION
41/175
fOSC2
fCPU
RUN
NORMAL RUN MODE
REQUEST
ST72321M6 ST72321M9
POWER SAVING MODES (Cont’d)
8.3 WAIT MODE
WAIT mode places the MCU in a low power consumption mode by stopping the CPU.
This power saving mode is selected by calling the
‘WFI’ instruction.
All peripherals remain active. During WAIT mode,
the I[1:0] bits of the CC register are forced to ‘10’,
to enable all interrupts. All other registers and
memory remain unchanged. The MCU remains in
WAIT mode until an interrupt or RESET occurs,
whereupon the Program Counter branches to the
starting address of the interrupt or Reset service
routine.
The MCU will remain in WAIT mode until a Reset
or an Interrupt occurs, causing it to wake up.
Refer to Figure 24.
Figure 24. WAIT Mode Flow-chart
WFI INSTRUCTION
OSCILLATOR
PERIPHERALS
CPU
I[1:0] BITS
ON
ON
OFF
10
N
RESET
Y
N
INTERRUPT
Y
OSCILLATOR
PERIPHERALS
CPU
I[1:0] BITS
ON
OFF
ON
10
256 OR 4096 CPU CLOCK
CYCLE DELAY
OSCILLATOR
ON
PERIPHERALS ON
CPU
ON
I[1:0] BITS
XX 1)
FETCH RESET VECTOR
OR SERVICE INTERRUPT
Note:
1. Before servicing an interrupt, the CC register is
pushed on the stack. The I[1:0] bits of the CC register are set to the current software priority level of
the interrupt routine and recovered when the CC
register is popped.
42/175
ST72321M6 ST72321M9
POWER SAVING MODES (Cont’d)
8.4 ACTIVE-HALT AND HALT MODES
Active-halt and Halt modes are the two lowest
power consumption modes of the MCU. They are
both entered by executing the ‘HALT’ instruction.
The decision to enter either in Active-halt or Halt
mode is given by the MCC/RTC interrupt enable
flag (OIE bit in MCCSR register).
MCCSR
OIE bit
Power Saving Mode entered when HALT
instruction is executed
0
Halt mode
1
ACTIVE-HALT mode
depending on option byte). Otherwise, the ST7 enters HALT mode for the remaining tDELAY period.
Figure 25. Active-halt Timing Overview
RUN
ACTIVE 256 OR 4096 CPU
HALT
CYCLE DELAY 1)
HALT
INSTRUCTION
[MCCSR.OIE=1]
RESET
OR
INTERRUPT
RUN
FETCH
VECTOR
Figure 26. Active-halt Mode Flow-chart
8.4.1 ACTIVE-HALT MODE
ACTIVE-HALT mode is the lowest power consumption mode of the MCU with a real-time clock
available. It is entered by executing the ‘HALT’ instruction when the OIE bit of the Main Clock Controller Status register (MCCSR) is set (see section
9.2 on page 53 for more details on the MCCSR
register).
The MCU can exit Active-halt mode on reception
of an MCC/RTC interrupt or a RESET. When exiting Active-halt mode by means of an interrupt, no
256 or 4096 CPU cycle delay occurs. The CPU
resumes operation by servicing the interrupt or by
fetching the reset vector which woke it up (see Figure 26).
When entering Active-halt mode, the I[1:0] bits in
the CC register are forced to ‘10b’ to enable interrupts. Therefore, if an interrupt is pending, the
MCU wakes up immediately.
In Active-halt mode, only the main oscillator and its
associated counter (MCC/RTC) are running to
keep a wake-up time base. All other peripherals
are not clocked except those which get their clock
supply from another clock generator (such as external or auxiliary oscillator).
The safeguard against staying locked in Activehalt mode is provided by the oscillator interrupt.
Note: As soon as the interrupt capability of one of
the oscillators is selected (MCCSR.OIE bit set),
entering Active-halt mode while the Watchdog is
active does not generate a RESET.
This means that the device cannot spend more
than a defined delay in this power saving mode.
CAUTION: When exiting Active-halt mode following an MCC/RTC interrupt, OIE bit of MCCSR register must not be cleared before tDELAY after the
interrupt occurs (tDELAY = 256 or 4096 tCPU delay
43/175
HALT INSTRUCTION
(MCCSR.OIE=1)
OSCILLATOR
PERIPHERALS 2)
CPU
I[1:0] BITS
N
N
INTERRUPT 4)
Y
ON
OFF
OFF
10
RESET
Y
OSCILLATOR
PERIPHERALS
CPU
I[1:0] BITS
ON
OFF
ON
XX 3)
256 OR 4096 CPU CLOCK
CYCLE DELAY
OSCILLATOR
PERIPHERALS
CPU
I[1:0] BITS
ON
ON
ON
XX 3)
FETCH RESET VECTOR
OR SERVICE INTERRUPT
Notes:
1. This delay occurs only if the MCU exits Activehalt mode by means of a RESET.
2. Peripheral clocked with an external clock source
can still be active.
3. Before servicing an interrupt, the CC register is
pushed on the stack. The I[1:0] bits of the CC register are set to the current software priority level of
the interrupt routine and restored when the CC
register is popped.
4. In Flash devices only the MCC/RTC interrupt
can exit the MCU from Active-halt mode.
ST72321M6 ST72321M9
POWER SAVING MODES (Cont’d)
8.4.2 HALT MODE
The Halt mode is the lowest power consumption
mode of the MCU. It is entered by executing the
‘HALT’ instruction when the OIE bit of the Main
Clock Controller Status register (MCCSR) is
cleared (see section 9.2 on page 53 for more details on the MCCSR register).
The MCU can exit Halt mode on reception of either
a specific interrupt (see Table 8, “Interrupt Mapping,” on page 37) or a RESET. When exiting Halt
mode by means of a RESET or an interrupt, the
oscillator is immediately turned on and the 256 or
4096 CPU cycle delay is used to stabilize the oscillator. After the start up delay, the CPU resumes
operation by servicing the interrupt or by fetching
the reset vector which woke it up (see Figure 28).
When entering Halt mode, the I[1:0] bits in the CC
register are forced to ‘10b’to enable interrupts.
Therefore, if an interrupt is pending, the MCU
wakes up immediately.
In Halt mode, the main oscillator is turned off causing all internal processing to be stopped, including
the operation of the on-chip peripherals. All peripherals are not clocked except the ones which get
their clock supply from another clock generator
(such as an external or auxiliary oscillator).
The compatibility of Watchdog operation with Halt
mode is configured by the “WDGHALT” option bit
of the option byte. The HALT instruction when executed while the Watchdog system is enabled, can
generate a Watchdog RESET (see section 13.1 on
page 167 for more details).
Figure 27. Halt Timing Overview
RUN
HALT
HALT
INSTRUCTION
[MCCSR.OIE=0]
44/175
256 OR 4096 CPU
CYCLE DELAY
RUN
RESET
OR
INTERRUPT
FETCH
VECTOR
Figure 28. Halt Mode Flow-chart
HALT INSTRUCTION
(MCCSR.OIE=0)
ENABLE
WDGHALT 1)
WATCHDOG
0
DISABLE
1
WATCHDOG
RESET
OSCILLATOR
OFF
PERIPHERALS 2) OFF
CPU
OFF
I[1:0] BITS
10
N
RESET
N
Y
INTERRUPT 3)
Y
OSCILLATOR
ON
PERIPHERALS OFF
CPU
ON
I[1:0] BITS
XX 4)
256 OR 4096 CPU CLOCK
CYCLE DELAY
OSCILLATOR
ON
PERIPHERALS ON
CPU
ON
I[1:0] BITS
XX 4)
FETCH RESET VECTOR
OR SERVICE INTERRUPT
Notes:
1. WDGHALT is an option bit. See option byte section for more details.
2. Peripheral clocked with an external clock source
can still be active.
3. Only some specific interrupts can exit the MCU
from Halt mode (such as external interrupt). Refer
to Table 8, “Interrupt Mapping,” on page 37 for
more details.
4. Before servicing an interrupt, the CC register is
pushed on the stack. The I[1:0] bits of the CC register are set to the current software priority level of
the interrupt routine and recovered when the CC
register is popped.
ST72321M6 ST72321M9
POWER SAVING MODES (Cont’d)
8.4.2.1 Halt Mode Recommendations
– Make sure that an external event is available to
wake up the microcontroller from Halt mode.
– When using an external interrupt to wake up the
microcontroller, reinitialize the corresponding I/O
as “Input Pull-up with Interrupt” before executing
the HALT instruction. The main reason for this is
that the I/O may be wrongly configured due to external interference or by an unforeseen logical
condition.
– For the same reason, reinitialize the level sensitiveness of each external interrupt as a precautionary measure.
– The opcode for the HALT instruction is 0x8E. To
avoid an unexpected HALT instruction due to a
program counter failure, it is advised to clear all
occurrences of the data value 0x8E from memo-
45/175
ry. For example, avoid defining a constant in
ROM with the value 0x8E.
– As the HALT instruction clears the interrupt mask
in the CC register to allow interrupts, the user
may choose to clear all pending interrupt bits before executing the HALT instruction. This avoids
entering other peripheral interrupt routines after
executing the external interrupt routine corresponding to the wake-up event (reset or external
interrupt).
Related Documentation
AN 980: ST7 Keypad Decoding Techniques, Implementing Wake-Up on Keystroke
AN1014: How to Minimize the ST7 Power Consumption
AN1605: Using an active RC to wakeup the
ST7LITE0 from power saving mode
ST72321M6 ST72321M9
I/O PORTS (Cont’d)
8.4.3 I/O Port Implementation
The I/O port register configurations are summarised as follows.
PA3, PB7, PB3, PF2 (without pull-up)
MODE
floating input
floating interrupt input
open drain output
push-pull output
Standard Ports
PA5:4, PC7:0, PD7:0, PE7:34,
PE1:0, PF7:3, PG7:0, PH7:0
MODE
floating input
pull-up input
open drain output
push-pull output
DDR
0
0
1
1
OR
0
1
0
1
DDR
0
0
1
1
OR
0
1
0
1
True Open Drain Ports
PA7:6
MODE
floating input
open drain (high sink ports)
Interrupt Ports
PA2:0, PB6:5, PB4, PB2:0, PF1:0 (with pull-up)
MODE
floating input
pull-up interrupt input
open drain output
push-pull output
DDR
0
0
1
1
OR
0
1
0
1
DDR
0
1
Pull-up Input Port
PE2
MODE
pull-up input
Table 10. Port Configuration
Port
Port A
Port B
Port C
Port D
Port E
Port F
Port G
Port H
46/175
Pin name
PA7:6
PA5:4
PA3
PA2:0
PB7, PB3
PB6:5, PB4,
PB2:0
PC7:0
PD7:0
PE7:3, PE1:0
PE2
PF7:3
PF2
PF1:0
PG7:0
PH7:0
Input
Output
OR = 0
OR = 1
floating
OR = 0
OR = 1
floating
floating
floating
floating
pull-up
floating interrupt
pull-up interrupt
floating interrupt
true open-drain
open drain
push-pull
open drain
push-pull
open drain
push-pull
open drain
push-pull
floating
pull-up interrupt
open drain
push-pull
floating
floating
floating
pull-up
open drain
pull-up
open drain
pull-up
open drain
pull-up input only
pull-up
open drain
floating interrupt
open drain
pull-up interrupt
open drain
pull-up
open drain
pull-up
open drain
push-pull
push-pull
push-pull
floating
floating
floating
floating
floating
push-pull
push-pull
push-pull
push-pull
push-pull
ST72321M6 ST72321M9
I/O PORTS (Cont’d)
Table 11. I/O Port Register Map and Reset Values
Address
(Hex.)
Register
Label
Reset Value
of all I/O port registers
0000h
PADR
0001h
PADDR
0002h
PAOR
0003h
PBDR
0004h
PBDDR
0005h
PBOR
0006h
PCDR
0007h
PCDDR
0008h
PCOR
0009h
PDDR
000Ah
PDDDR
000Bh
PDOR
000Ch
PEDR
000Dh
PEDDR
000Eh
PEOR
000Fh
PFDR
0010h
PFDDR
0011h
PFOR
0012h
PGDR
0013h
PGDDR
0014h
PGOR
0015h
PHDR
0016h
PHDDR
0017h
PHOR
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
MSB
LSB
MSB
LSB
MSB
LSB
MSB
LSB
MSB
LSB
MSB
LSB
MSB
LSB
MSB
LSB
Related Documentation
AN 970: SPI Communication between ST7 and
EEPROM
47/175
AN1045: S/W implementation of I2C bus master
AN1048: Software LCD driver
ST72321M6 ST72321M9
9 ON-CHIP PERIPHERALS
9.1 WATCHDOG TIMER (WDG)
9.1.1 Introduction
The Watchdog timer is used to detect the occurrence of a software fault, usually generated by external interference or by unforeseen logical conditions, which causes the application program to
abandon its normal sequence. The Watchdog circuit generates an MCU reset on expiry of a programmed time period, unless the program refreshes the counter’s contents before the T6 bit becomes cleared.
9.1.2 Main Features
■ Programmable free-running downcounter
■ Programmable reset
■ Reset (if watchdog activated) when the T6 bit
reaches zero
■ Optional
reset
on
HALT
instruction
(configurable by option byte)
■ Hardware Watchdog selectable by option byte
9.1.3 Functional Description
The counter value stored in the Watchdog Control
register (WDGCR bits T[6:0]), is decremented
every 16384 fOSC2 cycles (approx.), and the
length of the timeout period can be programmed
by the user in 64 increments.
If the watchdog is activated (the WDGA bit is set)
and when the 7-bit timer (bits T[6:0]) rolls over
from 40h to 3Fh (T6 becomes cleared), it initiates
a reset cycle pulling the reset pin low for typically
30 µs.
The application program must write in the
WDGCR register at regular intervals during normal
operation to prevent an MCU reset. This downcounter is free-running: it counts down even if the
watchdog is disabled. The value to be stored in the
WDGCR register must be between FFh and C0h:
– The WDGA bit is set (watchdog enabled)
– The T6 bit is set to prevent generating an immediate reset
– The T[5:0] bits contain the number of increments
which represents the time delay before the
watchdog produces a reset (see Figure 30. Approximate Timeout Duration). The timing varies
between a minimum and a maximum value due
to the unknown status of the prescaler when writing to the WDGCR register (see Figure 31).
Following a reset, the watchdog is disabled. Once
activated it cannot be disabled, except by a reset.
The T6 bit can be used to generate a software reset (the WDGA bit is set and the T6 bit is cleared).
If the watchdog is activated, the HALT instruction
will generate a Reset.
Figure 29. Watchdog Block Diagram
RESET
fOSC2
MCC/RTC
WATCHDOG CONTROL REGISTER (WDGCR)
DIV 64
WDGA
T6
T5
T4
T3
T2
T1
6-BIT DOWNCOUNTER (CNT)
12-BIT MCC
RTC COUNTER
MSB
11
48/175
LSB
6 5
0
TB[1:0] bits
(MCCSR
Register)
WDG PRESCALER
DIV 4
T0
ST72321M6 ST72321M9
WATCHDOG TIMER (Cont’d)
9.1.4 How to Program the Watchdog Timeout
Figure 30 shows the linear relationship between
the 6-bit value to be loaded in the Watchdog Counter (CNT) and the resulting timeout duration in milliseconds. This can be used for a quick calculation
without taking the timing variations into account. If
more precision is needed, use the formulae in Figure 31.
Caution: When writing to the WDGCR register, always write 1 in the T6 bit to avoid generating an
immediate reset.
Figure 30. Approximate Timeout Duration
3F
38
CNT Value (hex.)
30
28
20
18
10
08
00
1.5
18
34
50
65
82
Watchdog timeout (ms) @ 8 MHz. fOSC2
49/175
98
114
128
ST72321M6 ST72321M9
WATCHDOG TIMER (Cont’d)
Figure 31. Exact Timeout Duration (tmin and tmax)
WHERE:
tmin0 = (LSB + 128) x 64 x tOSC2
tmax0 = 16384 x tOSC2
tOSC2 = 125 ns if fOSC2=8 MHz
CNT = Value of T[5:0] bits in the WDGCR register (6 bits)
MSB and LSB are values from the table below depending on the timebase selected by the TB[1:0] bits
in the MCCSR register
TB1 Bit
TB0 Bit
(MCCSR Reg.) (MCCSR Reg.)
0
0
0
1
1
0
1
1
Selected MCCSR
Timebase
MSB
LSB
2ms
4ms
10ms
25ms
4
8
20
49
59
53
35
54
To calculate the minimum Watchdog Timeout (tmin):
IF CNT < MSB
------------4
THEN t min = t min0 + 16384 × CNT × tosc2
4CNT
ELSE t min = t min0 + 16384 × ⎛⎝ CNT – 4CNT
----------------- ⎞ + ( 192 + LSB ) × 64 × ----------------MSB ⎠
MSB
×
t
osc2
To calculate the maximum Watchdog Timeout (tmax):
IF CNT ≤ MSB
------------4
THEN t max = t max0 + 16384 × CNT × t osc2
4CNT
ELSEt max = t max0 + 16384 × ⎛⎝ CNT – 4CNT
----------------- ⎞ + ( 192 + LSB ) × 64 × ----------------MSB
MSB ⎠
Note: In the above formulae, division results must be rounded down to the next integer value.
Example:
With 2 ms timeout selected in MCCSR register
Value of T[5:0] Bits in
WDGCR Register (Hex.)
00
3F
50/175
Min. Watchdog
Timeout (ms)
tmin
1.496
128
Max. Watchdog
Timeout (ms)
tmax
2.048
128.552
×
t
osc2
ST72321M6 ST72321M9
WATCHDOG TIMER (Cont’d)
9.1.5 Low Power Modes
Mode
SLOW
WAIT
Description
No effect on Watchdog.
No effect on Watchdog.
OIE bit in
MCCSR
register
WDGHALT bit
in Option
Byte
0
0
0
1
1
x
HALT
No Watchdog reset is generated. The MCU enters Halt mode. The Watchdog counter is decremented once and then stops counting and is no longer
able to generate a watchdog reset until the MCU receives an external interrupt or a reset.
If an external interrupt is received, the Watchdog restarts counting after 256
or 4096 CPU clocks. If a reset is generated, the Watchdog is disabled (reset
state) unless Hardware Watchdog is selected by option byte. For application recommendations see Section 9.1.7 below.
A reset is generated.
No reset is generated. The MCU enters Active Halt mode. The Watchdog
counter is not decremented. It stop counting. When the MCU receives an
oscillator interrupt or external interrupt, the Watchdog restarts counting immediately. When the MCU receives a reset the Watchdog restarts counting
after 256 or 4096 CPU clocks.
9.1.6 Hardware Watchdog Option
If Hardware Watchdog is selected by option byte,
the watchdog is always active and the WDGA bit in
the WDGCR is not used. Refer to the Option Byte
description.
9.1.7 Using Halt Mode with the WDG
(WDGHALT option)
The following recommendation applies if Halt
mode is used when the watchdog is enabled.
– Before executing the HALT instruction, refresh
the WDG counter, to avoid an unexpected WDG
reset immediately after waking up the microcontroller.
9.1.8 Interrupts
None.
51/175
9.1.9 Register Description
CONTROL REGISTER (WDGCR)
Read/Write
Reset Value: 0111 1111 (7Fh)
7
WDGA
0
T6
T5
T4
T3
T2
T1
T0
Bit 7 = WDGA Activation bit.
This bit is set by software and only cleared by
hardware after a reset. When WDGA = 1, the
watchdog can generate a reset.
0: Watchdog disabled
1: Watchdog enabled
Note: This bit is not used if the hardware watchdog option is enabled by option byte.
Bit 6:0 = T[6:0] 7-bit counter (MSB to LSB).
These bits contain the value of the watchdog
counter. It is decremented every 16384 fOSC2 cycles (approx.). A reset is produced when it rolls
over from 40h to 3Fh (T6 becomes cleared).
ST72321M6 ST72321M9
Table 12. Watchdog Timer Register Map and Reset Values
Address
(Hex.)
Register
Label
7
6
5
4
3
2
1
0
002Ah
WDGCR
Reset Value
WDGA
0
T6
1
T5
1
T4
1
T3
1
T2
1
T1
1
T0
1
52/175
ST72321M6 ST72321M9
9.2 MAIN CLOCK CONTROLLER WITH REAL-TIME CLOCK AND BEEPER (MCC/RTC)
The Main Clock Controller consists of three different functions:
■ a programmable CPU clock prescaler
■ a clock-out signal to supply external devices
■ a real-time clock timer with interrupt capability
Each function can be used independently and simultaneously.
9.2.1 Programmable CPU Clock Prescaler
The programmable CPU clock prescaler supplies
the clock for the ST7 CPU and its internal peripherals. It manages Slow power saving mode (See
Section 8.2 SLOW MODE for more details).
The prescaler selects the fCPU main clock frequency and is controlled by three bits in the MCCSR
register: CP[1:0] and SMS.
9.2.2 Clock-out Capability
The clock-out capability is an alternate function of
an I/O port pin that outputs a fCPU clock to drive
external devices. It is controlled by the MCO bit in
the MCCSR register.
CAUTION: When selected, the clock out pin suspends the clock during Active-halt mode.
9.2.3 Real-Time Clock Timer (RTC)
The counter of the real-time clock timer allows an
interrupt to be generated based on an accurate
real-time clock. Four different time bases depending directly on fOSC2 are available. The whole
functionality is controlled by four bits of the MCCSR register: TB[1:0], OIE and OIF.
When the RTC interrupt is enabled (OIE bit set),
the ST7 enters Active-halt mode when the HALT
instruction is executed. See Section 8.4 ACTIVEHALT AND HALT MODES for more details.
9.2.4 Beeper
The beep function is controlled by the MCCBCR
register. It can output three selectable frequencies
on the BEEP pin (I/O port alternate function).
Figure 32. Main Clock Controller (MCC/RTC) Block Diagram
BC1 BC0
MCCBCR
BEEP
BEEP SIGNAL
SELECTION
MCO
12-BIT MCC RTC
COUNTER
DIV 64
MCO CP1 CP0 SMS TB1 TB0 OIE
MCCSR
fOSC2
DIV 2, 4, 8, 16
OIF
MCC/RTC INTERRUPT
1
0
53/175
TO
WATCHDOG
TIMER
fCPU
CPU CLOCK
TO CPU AND
PERIPHERALS
ST72321M6 ST72321M9
MAIN CLOCK CONTROLLER WITH REAL-TIME CLOCK (Cont’d)
9.2.5 Low Power Modes
Bit 6:5 = CP[1:0] CPU clock prescaler
Mode
Description
These bits select the CPU clock prescaler which is
No effect on MCC/RTC peripheral.
applied in the different slow modes. Their action is
Wait
MCC/RTC interrupt cause the device to exit
conditioned by the setting of the SMS bit. These
from Wait mode.
two bits are set and cleared by software
Activehalt
Halt
No effect on MCC/RTC counter (OIE bit is
set), the registers are frozen.
MCC/RTC interrupt cause the device to exit
from Active-halt mode.
MCC/RTC counter and registers are frozen.
MCC/RTC operation resumes when the
MCU is woken up by an interrupt with “exit
from Halt” capability.
9.2.6 Interrupts
The MCC/RTC interrupt event generates an interrupt if the OIE bit of the MCCSR register is set and
the interrupt mask in the CC register is not active
(RIM instruction).
Interrupt Event
Time base overflow
event
Enable
Event
Control
Flag
Bit
OIF
OIE
Exit
from
Wait
Exit
from
Halt
Yes
No 1)
Note:
The MCC/RTC interrupt wakes up the MCU from
Active-halt mode, not from Halt mode.
9.2.7 Register Description
MCC CONTROL/STATUS REGISTER (MCCSR)
Read/Write
Reset Value: 0000 0000 (00h)
7
MCO
0
CP1
CP0
SMS
TB1
TB0
OIE
CP1
CP0
fOSC2 / 2
0
0
fOSC2 / 4
0
1
fOSC2 / 8
1
0
fOSC2 / 16
1
1
Bit 4 = SMS Slow mode select
This bit is set and cleared by software.
0: Normal mode. fCPU = fOSC2
1: Slow mode. fCPU is given by CP1, CP0
See Section 8.2 SLOW MODE and Section 9.2
MAIN CLOCK CONTROLLER WITH REAL-TIME
CLOCK AND BEEPER (MCC/RTC) for more details.
Bit 3:2 = TB[1:0] Time base control
These bits select the programmable divider time
base. They are set and cleared by software.
Time Base
Counter
Prescaler f
OSC2 =4 MHz fOSC2=8 MHz
TB1
TB0
16000
4 ms
2 ms
0
0
32000
8 ms
4 ms
0
1
80000
20 ms
10 ms
1
0
200000
50 ms
25 ms
1
1
A modification of the time base is taken into account at the end of the current period (previously
set) to avoid an unwanted time shift. This allows to
use this time base as a real-time clock.
OIF
Bit 7 = MCO Main clock out selection
This bit enables the MCO alternate function on the
PF0 I/O port. It is set and cleared by software.
0: MCO alternate function disabled (I/O pin free for
general-purpose I/O)
1: MCO alternate function enabled (fCPU on I/O
port)
Note: To reduce power consumption, the MCO
function is not active in Active-halt mode.
54/175
fCPU in Slow mode
Bit 1 = OIE Oscillator interrupt enable
This bit set and cleared by software.
0: Oscillator interrupt disabled
1: Oscillator interrupt enabled
This interrupt can be used to exit from Active-halt
mode.
When this bit is set, calling the ST7 software HALT
instruction enters the Active-halt power saving
mode.
ST72321M6 ST72321M9
MAIN CLOCK CONTROLLER WITH REAL-TIME CLOCK (Cont’d)
MCC BEEP CONTROL REGISTER (MCCBCR)
Bit 0 = OIF Oscillator interrupt flag
This bit is set by hardware and cleared by software
Read/Write
reading the MCCSR register. It indicates when set
Reset Value: 0000 0000 (00h)
that the main oscillator has reached the selected
elapsed time (TB1:0).
7
0
0: Timeout not reached
1: Timeout reached
0
0
0
0
0
0
BC1 BC0
CAUTION: The BRES and BSET instructions
must not be used on the MCCSR register to avoid
Bit 7:2 = Reserved, must be kept cleared.
unintentionally clearing the OIF bit.
Bit 1:0 = BC[1:0] Beep control
These 2 bits select the PF1 pin beep capability.
BC1
BC0
Beep mode with fOSC2=8 MHz
0
0
Off
0
1
~2 kHz
1
0
~1 kHz
1
1
~500 Hz
Output
Beep signal
~50% duty cycle
The beep output signal is available in Active-halt
mode but has to be disabled to reduce the consumption.
Table 13. Main Clock Controller Register Map and Reset Values
Address
(Hex.)
002Bh
002Ch
002Dh
55/175
Register
Label
SICSR
Reset Value
MCCSR
Reset Value
MCCBCR
Reset Value
7
6
5
4
3
2
1
0
AVDS
0
MCO
0
AVDIE
0
CP1
0
AVDF
0
CP0
0
LVDRF
x
SMS
0
0
TB1
0
0
TB0
0
0
0
0
0
0
0
0
OIE
0
BC1
0
WDGRF
x
OIF
0
BC0
0
ST72321M6 ST72321M9
9.3 PWM AUTO-RELOAD TIMER (ART)
9.3.1 Introduction
The Pulse Width Modulated Auto-Reload Timer
on-chip peripheral consists of an 8-bit auto reload
counter with compare/capture capabilities and of a
7-bit prescaler clock source.
These resources allow five possible operating
modes:
– Generation of up to 4 independent PWM signals
– Output compare and Time base interrupt
– Up to two input capture functions
– External event detector
– Up to two external interrupt sources
The three first modes can be used together with a
single counter frequency.
The timer can be used to wake up the MCU from
Wait and Halt modes.
Figure 33. PWM Auto-Reload Timer Block Diagram
OEx
PWMCR
OCRx
REGISTER
OPx
DCRx
REGISTER
LOAD
PWMx
PORT
ALTERNATE
FUNCTION
POLARITY
CONTROL
COMPARE
8-BIT COUNTER
ARR
REGISTER
INPUT CAPTURE
CONTROL
ARTICx
ICSx
ARTCLK
ICIEx
LOAD
(CAR REGISTER)
LOAD
ICFx
ICRx
REGISTER
ICCSR
ICx INTERRUPT
fEXT
fCOUNTER
fCPU
MUX
fINPUT
EXCL
PROGRAMMABLE
PRESCALER
CC2
CC1
CC0
TCE
FCRL
OIE
OVF
ARTCSR
OVF INTERRUPT
56/175
ST72321M6 ST72321M9
ON-CHIP PERIPHERALS (Cont’d)
9.3.2 Functional Description
Counter
The free running 8-bit counter is fed by the output
of the prescaler, and is incremented on every rising edge of the clock signal.
It is possible to read or write the contents of the
counter on the fly by reading or writing the Counter
Access register (ARTCAR).
When a counter overflow occurs, the counter is
automatically reloaded with the contents of the
ARTARR register (the prescaler is not affected).
Counter clock and prescaler
The counter clock frequency is given by:
fCOUNTER = fINPUT / 2CC[2:0]
The timer counter’s input clock (fINPUT) feeds the
7-bit programmable prescaler, which selects one
of the 8 available taps of the prescaler, as defined
by CC[2:0] bits in the Control/Status Register
(ARTCSR). Thus the division factor of the prescaler can be set to 2n (where n = 0, 1,..7).
This fINPUT frequency source is selected through
the EXCL bit of the ARTCSR register and can be
either the fCPU or an external input frequency fEXT.
The clock input to the counter is enabled by the
TCE (Timer Counter Enable) bit in the ARTCSR
register. When TCE is reset, the counter is
stopped and the prescaler and counter contents
are frozen. When TCE is set, the counter runs at
the rate of the selected clock source.
Counter and Prescaler Initialization
After RESET, the counter and the prescaler are
cleared and fINPUT = fCPU.
The counter can be initialized by:
– Writing to the ARTARR register and then setting
the FCRL (Force Counter Re-Load) and the TCE
(Timer Counter Enable) bits in the ARTCSR register.
– Writing to the ARTCAR counter access register,
In both cases the 7-bit prescaler is also cleared,
whereupon counting will start from a known value.
Direct access to the prescaler is not possible.
Output compare control
The timer compare function is based on four different comparisons with the counter (one for each
PWMx output). Each comparison is made between the counter value and an output compare
register (OCRx) value. This OCRx register can not
be accessed directly, it is loaded from the duty cycle register (PWMDCRx) at each overflow of the
counter.
This double buffering method avoids glitch generation when changing the duty cycle on the fly.
Figure 34. Output compare control
fCOUNTER
ARTARR=FDh
COUNTER
FDh
FEh
FFh
OCRx
PWMDCRx
PWMx
57/175
FDh
FEh
FFh
FDh
FEh
FDh
FDh
FEh
FEh
FFh
ST72321M6 ST72321M9
ON-CHIP PERIPHERALS (Cont’d)
Independent PWM signal generation
This mode allows up to four Pulse Width Modulated signals to be generated on the PWMx output
pins with minimum core processing overhead.
This function is stopped during HALT mode.
Each PWMx output signal can be selected independently using the corresponding OEx bit in the
PWM Control register (PWMCR). When this bit is
set, the corresponding I/O pin is configured as output push-pull alternate function.
The PWM signals all have the same frequency
which is controlled by the counter period and the
ARTARR register value.
fPWM = fCOUNTER / (256 - ARTARR)
When a counter overflow occurs, the PWMx pin
level is changed depending on the corresponding
OPx (output polarity) bit in the PWMCR register.
When the counter reaches the value contained in
one of the output compare register (OCRx) the
corresponding PWMx pin level is restored.
It should be noted that the reload values will also
affect the value and the resolution of the duty cycle
of the PWM output signal. To obtain a signal on a
PWMx pin, the contents of the OCRx register must
be greater than the contents of the ARTARR register.
The maximum available resolution for the PWMx
duty cycle is:
Resolution = 1 / (256 - ARTARR)
Note: To get the maximum resolution (1/256), the
ARTARR register must be 0. With this maximum
resolution, 0% and 100% can be obtained by
changing the polarity.
Figure 35. PWM Auto-reload Timer Function
COUNTER
255
DUTY CYCLE
REGISTER
(PWMDCRx)
AUTO-RELOAD
REGISTER
(ARTARR)
PWMx OUTPUT
000
t
WITH OEx=1
AND OPx=0
WITH OEx=1
AND OPx=1
Figure 36. PWM Signal from 0% to 100% Duty Cycle
fCOUNTER
ARTARR=FDh
COUNTER
FDh
FEh
FFh
FDh
FEh
FFh
FDh
FEh
PWMx OUTPUT
WITH OEx=1
AND OPx=0
OCRx=FCh
OCRx=FDh
OCRx=FEh
OCRx=FFh
t
58/175
ST72321M6 ST72321M9
ON-CHIP PERIPHERALS (Cont’d)
Output compare and Time base interrupt
On overflow, the OVF flag of the ARTCSR register
is set and an overflow interrupt request is generated if the overflow interrupt enable bit, OIE, in the
ARTCSR register, is set. The OVF flag must be reset by the user software. This interrupt can be
used as a time base in the application.
External clock and event detector mode
Using the fEXT external prescaler input clock, the
auto-reload timer can be used as an external clock
event detector. In this mode, the ARTARR register
is used to select the nEVENT number of events to
be counted before setting the OVF flag.
nEVENT = 256 - ARTARR
Caution: The external clock function is not available in HALT mode. If HALT mode is used in the application, prior to executing the HALT instruction,
the counter must be disabled by clearing the TCE
bit in the ARTCSR register to avoid spurious counter increments.
Figure 37. External Event Detector Example (3 counts)
fEXT=fCOUNTER
ARTARR=FDh
COUNTER
FDh
FEh
FFh
FDh
FEh
FFh
FDh
OVF
ARTCSR READ
INTERRUPT
IF OIE=1
ARTCSR READ
INTERRUPT
IF OIE=1
t
59/175
ST72321M6 ST72321M9
ON-CHIP PERIPHERALS (Cont’d)
Input capture function
This mode allows the measurement of external
signal pulse widths through ARTICRx registers.
Each input capture can generate an interrupt independently on a selected input signal transition.
This event is flagged by a set of the corresponding
CFx bits of the Input Capture Control/Status register (ARTICCSR).
These input capture interrupts are enabled
through the CIEx bits of the ARTICCSR register.
The active transition (falling or rising edge) is software programmable through the CSx bits of the
ARTICCSR register.
The read only input capture registers (ARTICRx)
are used to latch the auto-reload counter value
when a transition is detected on the ARTICx pin
(CFx bit set in ARTICCSR register). After fetching
the interrupt vector, the CFx flags can be read to
identify the interrupt source.
Note: After a capture detection, data transfer in
the ARTICRx register is inhibited until it is read
(clearing the CFx bit).
The timer interrupt remains pending while the CFx
flag is set when the interrupt is enabled (CIEx bit
set). This means, the ARTICRx register has to be
read at each capture event to clear the CFx flag.
External interrupt capability
This mode allows the Input capture capabilities to
be used as external interrupt sources. The interrupts are generated on the edge of the ARTICx
signal.
The edge sensitivity of the external interrupts is
programmable (CSx bit of ARTICCSR register)
and they are independently enabled through CIEx
bits of the ARTICCSR register. After fetching the
interrupt vector, the CFx flags can be read to identify the interrupt source.
During HALT mode, the external interrupts can be
used to wake up the micro (if the CIEx bit is set).
The timing resolution is given by auto-reload counter cycle time (1/fCOUNTER).
Note: During HALT mode, if both input capture
and external clock are enabled, the ARTICRx register value is not guaranteed if the input capture
pin and the external clock change simultaneously.
Figure 38. Input Capture Timing Diagram
fCOUNTER
COUNTER
01h
02h
03h
04h
05h
06h
07h
INTERRUPT
ARTICx PIN
CFx FLAG
xxh
04h
ICRx REGISTER
t
60/175
ST72321M6 ST72321M9
ON-CHIP PERIPHERALS (Cont’d)
9.3.3 Register Description
0: New transition not yet reached
1: Transition reached
CONTROL / STATUS REGISTER (ARTCSR)
Read/Write
Reset Value: 0000 0000 (00h)
7
EXCL
0
CC2
CC1
CC0
TCE
FCRL
OIE
COUNTER ACCESS REGISTER (ARTCAR)
Read/Write
Reset Value: 0000 0000 (00h)
OVF
7
Bit 7 = EXCL External Clock
This bit is set and cleared by software. It selects the
input clock for the 7-bit prescaler.
0: CPU clock.
1: External clock.
Bit 6:4 = CC[2:0] Counter Clock Control
These bits are set and cleared by software. They
determine the prescaler division ratio from fINPUT.
fCOUNTER
fINPUT
fINPUT / 2
fINPUT / 4
fINPUT / 8
fINPUT / 16
fINPUT / 32
fINPUT / 64
fINPUT / 128
CA6
CA5
CA4
CA3
CA2
CA1
CA0
Bit 7:0 = CA[7:0] Counter Access Data
These bits can be set and cleared either by hardware or by software. The ARTCAR register is used
to read or write the auto-reload counter “on the fly”
(while it is counting).
With fINPUT=8 MHz CC2 CC1 CC0
8 MHz
4 MHz
2 MHz
1 MHz
500 kHz
250 kHz
125 kHz
62.5 kHz
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
Bit 3 = TCE Timer Counter Enable
This bit is set and cleared by software. It puts the
timer in the lowest power consumption mode.
0: Counter stopped (prescaler and counter frozen).
1: Counter running.
Bit 2 = FCRL Force Counter Re-Load
This bit is write-only and any attempt to read it will
yield a logical zero. When set, it causes the contents
of ARTARR register to be loaded into the counter,
and the content of the prescaler register to be
cleared in order to initialize the timer before starting
to count.
Bit 1 = OIE Overflow Interrupt Enable
This bit is set and cleared by software. It allows to
enable/disable the interrupt which is generated
when the OVF bit is set.
0: Overflow Interrupt disable.
1: Overflow Interrupt enable.
Bit 0 = OVF Overflow Flag
This bit is set by hardware and cleared by software
reading the ARTCSR register. It indicates the transition of the counter from FFh to the ARTARR value.
61/175
CA7
0
AUTO-RELOAD REGISTER (ARTARR)
Read/Write
Reset Value: 0000 0000 (00h)
7
AR7
0
AR6
AR5
AR4
AR3
AR2
AR1
AR0
Bit 7:0 = AR[7:0] Counter Auto-Reload Data
These bits are set and cleared by software. They
are used to hold the auto-reload value which is automatically loaded in the counter when an overflow
occurs. At the same time, the PWM output levels
are changed according to the corresponding OPx
bit in the PWMCR register.
This register has two PWM management functions:
– Adjusting the PWM frequency
– Setting the PWM duty cycle resolution
PWM Frequency vs Resolution:
ARTARR
value
Resolution
0
[ 0..127 ]
[ 128..191 ]
[ 192..223 ]
[ 224..239 ]
8-bit
> 7-bit
> 6-bit
> 5-bit
> 4-bit
fPWM
Min
Max
~0.244 kHz
~0.244 kHz
~0.488 kHz
~0.977 kHz
~1.953 kHz
31.25 kHz
62.5 kHz
125 kHz
250 kHz
500 kHz
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.
PWMx output level
OPx
Counter <= OCRx
Counter > OCRx
1
0
0
1
0
1
Note: When an OPx bit is modified, the PWMx output signal polarity is immediately reversed.
62/175
0
DC6
DC5
DC4
DC3
DC2
DC1
DC0
Bit 7:0 = DC[7:0] Duty Cycle Data
These bits are set and cleared by software.
A PWMDCRx register is associated with the OCRx
register of each PWM channel to determine the
second edge location of the PWM signal (the first
edge location is common to all channels and given
by the ARTARR register). These PWMDCR registers allow the duty cycle to be set independently
for each PWM channel.
ST72321M6 ST72321M9
ON-CHIP PERIPHERALS (Cont’d)
INPUT CAPTURE
CONTROL / STATUS REGISTER (ARTICCSR)
Read/Write
Reset Value: 0000 0000 (00h)
INPUT CAPTURE REGISTERS (ARTICRx)
Read only
Reset Value: 0000 0000 (00h)
7
7
IC7
0
0
CS2
CS1
CIE2
CIE1
CF2
IC6
IC5
IC4
IC3
IC2
IC1
IC0
CF1
Bit 7:6 = Reserved, always read as 0.
Bit 5:4 = CS[2:1] Capture Sensitivity
These bits are set and cleared by software. They
determine the trigger event polarity on the corresponding input capture channel.
0: Falling edge triggers capture on channel x.
1: Rising edge triggers capture on channel x.
Bit 3:2 = CIE[2:1] Capture Interrupt Enable
These bits are set and cleared by software. They
enable or disable the Input capture channel interrupts independently.
0: Input capture channel x interrupt disabled.
1: Input capture channel x interrupt enabled.
Bit 1:0 = CF[2:1] Capture Flag
These bits are set by hardware and cleared by
software reading the corresponding ARTICRx register. Each CFx bit indicates that an input capture x
has occurred.
0: No input capture on channel x.
1: An input capture has occurred on channel x.
63/175
0
0
Bit 7:0 = IC[7:0] Input Capture Data
These read only bits are set and cleared by hardware. An ARTICRx register contains the 8-bit
auto-reload counter value transferred by the input
capture channel x event.
ST72321M6 ST72321M9
PWM AUTO-RELOAD TIMER (Cont’d)
Table 14. PWM Auto-Reload Timer Register Map and Reset Values
Address
(Hex.)
0073h
0074h
0075h
0076h
0077h
0078h
0079h
007Ah
007Bh
007Ch
007Dh
64/175
Register
Label
PWMDCR3
Reset Value
PWMDCR2
Reset Value
PWMDCR1
Reset Value
PWMDCR0
Reset Value
PWMCR
Reset Value
ARTCSR
Reset Value
ARTCAR
Reset Value
ARTARR
Reset Value
7
6
5
4
3
2
1
0
DC7
0
DC6
0
DC5
0
DC4
0
DC3
0
DC2
0
DC1
0
DC0
0
DC7
0
DC6
0
DC5
0
DC4
0
DC3
0
DC2
0
DC1
0
DC0
0
DC7
0
DC6
0
DC5
0
DC4
0
DC3
0
DC2
0
DC1
0
DC0
0
DC7
0
DC6
0
DC5
0
DC4
0
DC3
0
DC2
0
DC1
0
DC0
0
OE3
0
OE2
0
OE1
0
OE0
0
OP3
0
OP2
0
OP1
0
OP0
0
EXCL
0
CC2
0
CC1
0
CC0
0
TCE
0
FCRL
0
RIE
0
OVF
0
CA7
0
CA6
0
CA5
0
CA4
0
CA3
0
CA2
0
CA1
0
CA0
0
AR7
0
AR6
0
AR5
0
AR4
0
AR3
0
AR2
0
AR1
0
AR0
0
0
0
CS2
0
CS1
0
CIE2
0
CIE1
0
CF2
0
CF1
0
IC7
0
IC6
0
IC5
0
IC4
0
IC3
0
IC2
0
IC1
0
IC0
0
IC7
0
IC6
0
IC5
0
IC4
0
IC3
0
IC2
0
IC1
0
IC0
0
ARTICCSR
Reset Value
ARTICR1
Reset Value
ARTICR2
Reset Value
ST72321M6 ST72321M9
9.4 16-BIT TIMER
9.4.1 Introduction
The timer consists of a 16-bit free-running counter
driven by a programmable prescaler.
It may be used for a variety of purposes, including
pulse length measurement of up to two input signals (input capture) or generation of up to two output waveforms (output compare and PWM).
Pulse lengths and waveform periods can be modulated from a few microseconds to several milliseconds using the timer prescaler and the CPU
clock prescaler.
Some ST7 devices have two on-chip 16-bit timers.
They are completely independent, and do not
share any resources. They are synchronized after
a MCU reset as long as the timer clock frequencies are not modified.
This description covers one or two 16-bit timers. In
ST7 devices with two timers, register names are
prefixed with TA (Timer A) or TB (Timer B).
9.4.2 Main Features
■ Programmable prescaler: fCPU divided by 2, 4 or 8
■ Overflow status flag and maskable interrupt
■ External clock input (must be at least four times
slower than the CPU clock speed) with the choice
of active edge
■ 1 or 2 Output Compare functions each with:
– 2 dedicated 16-bit registers
– 2 dedicated programmable signals
– 2 dedicated status flags
– 1 dedicated maskable interrupt
■ 1 or 2 Input Capture functions each with:
– 2 dedicated 16-bit registers
– 2 dedicated active edge selection signals
– 2 dedicated status flags
– 1 dedicated maskable interrupt
■ Pulse width modulation mode (PWM)
■ One Pulse mode
■ Reduced Power Mode
■ 5 alternate functions on I/O ports (ICAP1, ICAP2,
OCMP1, OCMP2, EXTCLK)*
The Block Diagram is shown in Figure 39.
*Note: Some timer pins may not be available (not
bonded) in some ST7 devices. Refer to the device
pin out description.
65/175
When reading an input signal on a non-bonded
pin, the value will always be ‘1’.
9.4.3 Functional Description
9.4.3.1 Counter
The main block of the Programmable Timer is a
16-bit free running upcounter and its associated
16-bit registers. The 16-bit registers are made up
of two 8-bit registers called high and low.
Counter Register (CR):
– Counter High Register (CHR) is the most significant byte (MS Byte).
– Counter Low Register (CLR) is the least significant byte (LS Byte).
Alternate Counter Register (ACR)
– Alternate Counter High Register (ACHR) is the
most significant byte (MS Byte).
– Alternate Counter Low Register (ACLR) is the
least significant byte (LS Byte).
These two read-only 16-bit registers contain the
same value but with the difference that reading the
ACLR register does not clear the TOF bit (Timer
overflow flag), located in the Status register, (SR),
(see note at the end of paragraph titled 16-bit read
sequence).
Writing in the CLR register or ACLR register resets
the free running counter to the FFFCh value.
Both counters have a reset value of FFFCh (this is
the only value which is reloaded in the 16-bit timer). The reset value of both counters is also
FFFCh in One Pulse mode and PWM mode.
The timer clock depends on the clock control bits
of the CR2 register, as illustrated in Table 15 Clock
Control Bits. The value in the counter register repeats every 131072, 262144 or 524288 CPU clock
cycles depending on the CC[1:0] bits.
The timer frequency can be fCPU/2, fCPU/4, fCPU/8
or an external frequency.
ST72321M6 ST72321M9
16-BIT TIMER (Cont’d)
Figure 39. Timer Block Diagram
ST7 INTERNAL BUS
fCPU
MCU-PERIPHERAL INTERFACE
8 low
8
8
8
low
8
high
8
low
8
high
EXEDG
8
low
high
8
high
8-bit
buffer
low
8 high
16
1/2
1/4
1/8
OUTPUT
COMPARE
REGISTER
2
OUTPUT
COMPARE
REGISTER
1
COUNTER
REGISTER
ALTERNATE
COUNTER
REGISTER
EXTCLK
pin
INPUT
CAPTURE
REGISTER
1
INPUT
CAPTURE
REGISTER
2
16
16
16
CC[1:0]
TIMER INTERNAL BUS
16 16
OVERFLOW
DETECT
CIRCUIT
OUTPUT COMPARE
CIRCUIT
6
ICF1 OCF1 TOF ICF2 OCF2 TIMD
0
EDGE DETECT
CIRCUIT1
ICAP1
pin
EDGE DETECT
CIRCUIT2
ICAP2
pin
LATCH1
OCMP1
pin
LATCH2
OCMP2
pin
0
(Control/Status Register)
CSR
ICIE OCIE TOIE FOLV2 FOLV1 OLVL2 IEDG1 OLVL1
(Control Register 1) CR1
OC1E OC2E OPM PWM
CC1
CC0 IEDG2 EXEDG
(Control Register 2) CR2
(See note)
TIMER INTERRUPT
66/175
Note: If IC, OC and TO interrupt requests have separate vectors
then the last OR is not present (See device Interrupt Vector Table)
ST72321M6 ST72321M9
16-BIT TIMER (Cont’d)
16-bit read sequence: (from either the Counter
Register or the Alternate Counter Register).
Beginning of the sequence
At t0
Read
MS Byte
LS Byte
is buffered
Other
instructions
Read
At t0 +Δt LS Byte
Returns the buffered
LS Byte value at t0
Sequence completed
The user must read the MS Byte first, then the LS
Byte value is buffered automatically.
This buffered value remains unchanged until the
16-bit read sequence is completed, even if the
user reads the MS Byte several times.
After a complete reading sequence, if only the
CLR register or ACLR register are read, they return the LS Byte of the count value at the time of
the read.
Whatever the timer mode used (input capture, output compare, One Pulse mode or PWM mode) an
overflow occurs when the counter rolls over from
FFFFh to 0000h then:
– The TOF bit of the SR register is set.
– A timer interrupt is generated if:
– TOIE bit of the CR1 register is set and
– I bit of the CC register is cleared.
If one of these conditions is false, the interrupt remains pending to be issued as soon as they are
both true.
67/175
Clearing the overflow interrupt request is done in
two steps:
1. Reading the SR register while the TOF bit is set.
2. An access (read or write) to the CLR register.
Notes: The TOF bit is not cleared by accesses to
ACLR register. The advantage of accessing the
ACLR register rather than the CLR register is that
it allows simultaneous use of the overflow function
and reading the free running counter at random
times (for example, to measure elapsed time) without the risk of clearing the TOF bit erroneously.
The timer is not affected by WAIT mode.
In HALT mode, the counter stops counting until the
mode is exited. Counting then resumes from the
previous count (MCU awakened by an interrupt) or
from the reset count (MCU awakened by a Reset).
9.4.3.2 External Clock
The external clock (where available) is selected if
CC0 = 1 and CC1 = 1 in the CR2 register.
The status of the EXEDG bit in the CR2 register
determines the type of level transition on the external clock pin EXTCLK that will trigger the free running counter.
The counter is synchronized with the falling edge
of the internal CPU clock.
A minimum of four falling edges of the CPU clock
must occur between two consecutive active edges
of the external clock; thus the external clock frequency must be less than a quarter of the CPU
clock frequency.
ST72321M6 ST72321M9
16-BIT TIMER (Cont’d)
Figure 40. Counter Timing Diagram, Internal Clock Divided by 2
CPU CLOCK
INTERNAL RESET
TIMER CLOCK
COUNTER REGISTER
FFFD FFFE FFFF 0000
0001
0002
0003
TIMER OVERFLOW FLAG (TOF)
Figure 41. Counter Timing Diagram, Internal Clock Divided by 4
CPU CLOCK
INTERNAL RESET
TIMER CLOCK
COUNTER REGISTER
FFFC
FFFD
0000
0001
TIMER OVERFLOW FLAG (TOF)
Figure 42. Counter Timing Diagram, Internal Clock Divided By 8
CPU CLOCK
INTERNAL RESET
TIMER CLOCK
COUNTER REGISTER
FFFC
FFFD
0000
TIMER OVERFLOW FLAG (TOF)
Note: The MCU is in reset state when the internal reset signal is high, when it is low the MCU is running.
68/175
ST72321M6 ST72321M9
16-BIT TIMER (Cont’d)
9.4.3.3 Input Capture
In this section, the index, i, may be 1 or 2 because
there are two input capture functions in the 16-bit
timer.
The two 16-bit input capture registers (IC1R and
IC2R) are used to latch the value of the free running counter after a transition is detected on the
ICAPi pin (see Figure 43).
ICiR
MS Byte
ICiHR
LS Byte
ICiLR
ICiR register is a read-only register.
The active transition is software programmable
through the IEDGi bit of Control Registers (CRi).
Timing resolution is one count of the free running
counter: (fCPU/CC[1:0]).
Procedure:
To use the input capture function select the following in the CR2 register:
– Select the timer clock (CC[1:0]) (see Table 15
Clock Control Bits).
– Select the edge of the active transition on the
ICAP2 pin with the IEDG2 bit (the ICAP2 pin
must be configured as floating input or input with
pull-up without interrupt if this configuration is
available).
And select the following in the CR1 register:
– Set the ICIE bit to generate an interrupt after an
input capture coming from either the ICAP1 pin
or the ICAP2 pin
– Select the edge of the active transition on the
ICAP1 pin with the IEDG1 bit (the ICAP1pin must
be configured as floating input or input with pullup without interrupt if this configuration is available).
69/175
When an input capture occurs:
– ICFi bit is set.
– The ICiR register contains the value of the free
running counter on the active transition on the
ICAPi pin (see Figure 44).
– A timer interrupt is generated if the ICIE bit is set
and the I bit is cleared in the CC register. Otherwise, the interrupt remains pending until both
conditions become true.
Clearing the Input Capture interrupt request (that
is, clearing the ICFi bit) is done in two steps:
1. Reading the SR register while the ICFi bit is set.
2. An access (read or write) to the ICiLR register.
Notes:
1. After reading the ICiHR register, transfer of
input capture data is inhibited and ICFi will
never be set until the ICiLR register is also
read.
2. The ICiR register contains the free running
counter value which corresponds to the most
recent input capture.
3. The two input capture functions can be used
together even if the timer also uses the two output compare functions.
4. In One Pulse mode and PWM mode only Input
Capture 2 can be used.
5. The alternate inputs (ICAP1 and ICAP2) are
always directly connected to the timer. So any
transitions on these pins activates the input
capture function.
Moreover if one of the ICAPi pins is configured
as an input and the second one as an output,
an interrupt can be generated if the user toggles the output pin and if the ICIE bit is set.
This can be avoided if the input capture function i is disabled by reading the ICiHR (see note
1).
6. The TOF bit can be used with interrupt generation in order to measure events that go beyond
the timer range (FFFFh).
ST72321M6 ST72321M9
16-BIT TIMER (Cont’d)
Figure 43. Input Capture Block Diagram
ICAP1
pin
ICAP2
pin
(Control Register 1) CR1
EDGE DETECT
CIRCUIT2
EDGE DETECT
CIRCUIT1
ICIE
IEDG1
(Status Register) SR
IC2R Register
IC1R Register
ICF1
ICF2
0
16-BIT FREE RUNNING
COUNTER
CC1
CC0 IEDG2
Figure 44. Input Capture Timing Diagram
TIMER CLOCK
FF01
FF02
FF03
ICAPi PIN
ICAPi FLAG
ICAPi REGISTER
Note: The rising edge is the active edge.
70/175
0
(Control Register 2) CR2
16-BIT
COUNTER REGISTER
0
FF03
ST72321M6 ST72321M9
16-BIT TIMER (Cont’d)
9.4.3.4 Output Compare
In this section, the index, i, may be 1 or 2 because
there are two output compare functions in the 16bit timer.
This function can be used to control an output
waveform or indicate when a period of time has
elapsed.
When a match is found between the Output Compare register and the free running counter, the output compare function:
– Assigns pins with a programmable value if the
OCiE bit is set
– Sets a flag in the status register
– Generates an interrupt if enabled
Two 16-bit registers Output Compare Register 1
(OC1R) and Output Compare Register 2 (OC2R)
contain the value to be compared to the counter
register each timer clock cycle.
OCiR
MS Byte
OCiHR
LS Byte
OCiLR
These registers are readable and writable and are
not affected by the timer hardware. A reset event
changes the OCiR value to 8000h.
Timing resolution is one count of the free running
counter: (fCPU/CC[1:0]).
Procedure:
To use the output compare function, select the following in the CR2 register:
– Set the OCiE bit if an output is needed then the
OCMPi pin is dedicated to the output compare i
signal.
– Select the timer clock (CC[1:0]) (see Table 15
Clock Control Bits).
And select the following in the CR1 register:
– Select the OLVLi bit to applied to the OCMPi pins
after the match occurs.
– Set the OCIE bit to generate an interrupt if it is
needed.
When a match is found between OCiR register
and CR register:
– OCFi bit is set.
71/175
– The OCMPi pin takes OLVLi bit value (OCMPi
pin latch is forced low during reset).
– A timer interrupt is generated if the OCIE bit is
set in the CR1 register and the I bit is cleared in
the CC register (CC).
The OCiR register value required for a specific timing application can be calculated using the following formula:
Δ OCiR =
Δt * fCPU
PRESC
Where:
Δt
= Output compare period (in seconds)
fCPU
= CPU clock frequency (in hertz)
=
Timer prescaler factor (2, 4 or 8 dePRESC
pending on CC[1:0] bits, see Table 15
Clock Control Bits)
If the timer clock is an external clock, the formula
is:
Δ OCiR = Δt * fEXT
Where:
Δt
= Output compare period (in seconds)
fEXT
= External timer clock frequency (in hertz)
Clearing the output compare interrupt request
(that is, clearing the OCFi bit) is done by:
1. Reading the SR register while the OCFi bit is
set.
2. An access (read or write) to the OCiLR register.
The following procedure is recommended to prevent the OCFi bit from being set between the time
it is read and the write to the OCiR register:
– Write to the OCiHR register (further compares
are inhibited).
– Read the SR register (first step of the clearance
of the OCFi bit, which may be already set).
– Write to the OCiLR register (enables the output
compare function and clears the OCFi bit).
ST72321M6 ST72321M9
16-BIT TIMER (Cont’d)
Notes:
1. After a processor write cycle to the OCiHR register, the output compare function is inhibited
until the OCiLR register is also written.
2. If the OCiE bit is not set, the OCMPi pin is a
general I/O port and the OLVLi bit will not
appear when a match is found but an interrupt
could be generated if the OCIE bit is set.
3. In both internal and external clock modes,
OCFi and OCMPi are set while the counter
value equals the OCiR register value (see Figure 46 on page 73 for an example with fCPU/2
and Figure 47 on page 73 for an example with
fCPU/4). This behavior is the same in OPM or
PWM mode.
4. The output compare functions can be used both
for generating external events on the OCMPi
pins even if the input capture mode is also
used.
5. The value in the 16-bit OCiR register and the
OLVi bit should be changed after each successful comparison in order to control an output
waveform or establish a new elapsed timeout.
Forced Compare Output capability
When the FOLVi bit is set by software, the OLVLi
bit is copied to the OCMPi pin. The OLVi bit has to
be toggled in order to toggle the OCMPi pin when
it is enabled (OCiE bit = 1). The OCFi bit is then
not set by hardware, and thus no interrupt request
is generated.
The FOLVLi bits have no effect in both One Pulse
mode and PWM mode.
Figure 45. Output Compare Block Diagram
16 BIT FREE RUNNING
COUNTER
OC1E OC2E
CC1
CC0
(Control Register 2) CR2
16-bit
(Control Register 1) CR1
OUTPUT COMPARE
CIRCUIT
16-bit
OCIE
FOLV2 FOLV1 OLVL2
OLVL1
16-bit
Latch
2
OC1R Register
OCF1
OCF2
0
0
0
OC2R Register
(Status Register) SR
72/175
Latch
1
OCMP1
Pin
OCMP2
Pin
ST72321M6 ST72321M9
16-BIT TIMER (Cont’d)
Figure 46. Output Compare Timing Diagram, fTIMER = fCPU/2
INTERNAL CPU CLOCK
TIMER CLOCK
COUNTER REGISTER
2ECF 2ED0
OUTPUT COMPARE REGISTER i (OCRi)
2ED1 2ED2 2ED3 2ED4
2ED3
OUTPUT COMPARE FLAG i (OCFi)
OCMPi PIN (OLVLi = 1)
Figure 47. Output Compare Timing Diagram, fTIMER = fCPU/4
INTERNAL CPU CLOCK
TIMER CLOCK
COUNTER REGISTER
OUTPUT COMPARE REGISTER i (OCRi)
OUTPUT COMPARE FLAG i (OCFi)
OCMPi PIN (OLVLi = 1)
73/175
2ECF 2ED0
2ED1 2ED2 2ED3 2ED4
2ED3
ST72321M6 ST72321M9
16-BIT TIMER (Cont’d)
9.4.3.5 One Pulse Mode
One Pulse mode enables the generation of a
pulse when an external event occurs. This mode is
selected via the OPM bit in the CR2 register.
The One Pulse mode uses the Input Capture1
function and the Output Compare1 function.
Procedure:
To use One Pulse mode:
1. Load the OC1R register with the value corresponding to the length of the pulse (see the formula in the opposite column).
2. Select the following in the CR1 register:
– Using the OLVL1 bit, select the level to be applied to the OCMP1 pin after the pulse.
– Using the OLVL2 bit, select the level to be applied to the OCMP1 pin during the pulse.
– Select the edge of the active transition on the
ICAP1 pin with the IEDG1 bit (the ICAP1 pin
must be configured as floating input).
3. Select the following in the CR2 register:
– Set the OC1E bit, the OCMP1 pin is then dedicated to the Output Compare 1 function.
– Set the OPM bit.
– Select the timer clock CC[1:0] (see Table 15
Clock Control Bits).
One Pulse mode cycle
When
event occurs
on ICAP1
ICR1 = Counter
OCMP1 = OLVL2
Counter is reset
to FFFCh
ICF1 bit is set
When
Counter
= OC1R
OCMP1 = OLVL1
Then, on a valid event on the ICAP1 pin, the counter is initialized to FFFCh and OLVL2 bit is loaded
on the OCMP1 pin, the ICF1 bit is set and the value FFFDh is loaded in the IC1R register.
Because the ICF1 bit is set when an active edge
occurs, an interrupt can be generated if the ICIE
bit is set.
74/175
Clearing the Input Capture interrupt request (that
is, clearing the ICFi bit) is done in two steps:
1. Reading the SR register while the ICFi bit is set.
2. An access (read or write) to the ICiLR register.
The OC1R register value required for a specific
timing application can be calculated using the following formula:
OCiR Value =
t * fCPU
-5
PRESC
Where:
t
= Pulse period (in seconds)
fCPU = CPU clock frequency (in hertz)
PRESC = Timer prescaler factor (2, 4 or 8 depending on the CC[1:0] bits, see Table 15
Clock Control Bits)
If the timer clock is an external clock the formula is:
OCiR = t * fEXT -5
Where:
t
= Pulse period (in seconds)
= External timer clock frequency (in hertz)
fEXT
When the value of the counter is equal to the value
of the contents of the OC1R register, the OLVL1
bit is output on the OCMP1 pin, (See Figure 48).
Notes:
1. The OCF1 bit cannot be set by hardware in
One Pulse mode but the OCF2 bit can generate
an Output Compare interrupt.
2. When the Pulse Width Modulation (PWM) and
One Pulse mode (OPM) bits are both set, the
PWM mode is the only active one.
3. If OLVL1 = OLVL2 a continuous signal will be
seen on the OCMP1 pin.
4. The ICAP1 pin can not be used to perform input
capture. The ICAP2 pin can be used to perform
input capture (ICF2 can be set and IC2R can be
loaded) but the user must take care that the
counter is reset each time a valid edge occurs
on the ICAP1 pin and ICF1 can also generates
interrupt if ICIE is set.
5. When One Pulse mode is used OC1R is dedicated to this mode. Nevertheless OC2R and
OCF2 can be used to indicate a period of time
has been elapsed but cannot generate an output waveform because the level OLVL2 is dedicated to the One Pulse mode.
ST72321M6 ST72321M9
16-BIT TIMER (Cont’d)
Figure 48. One Pulse Mode Timing Example
COUNTER
2ED3
01F8
IC1R
01F8
FFFC FFFD FFFE
2ED0 2ED1 2ED2
FFFC FFFD
2ED3
ICAP1
OLVL2
OCMP1
OLVL1
OLVL2
compare1
Note: IEDG1 = 1, OC1R = 2ED0h, OLVL1 = 0, OLVL2 = 1
Figure 49. Pulse Width Modulation Mode Timing Example with 2 Output Compare Functions
2ED0 2ED1 2ED2
COUNTER 34E2 FFFC FFFD FFFE
OLVL2
OCMP1
compare2
OLVL1
compare1
34E2
FFFC
OLVL2
compare2
Note: OC1R = 2ED0h, OC2R = 34E2, OLVL1 = 0, OLVL2 = 1
Note: On timers with only one Output Compare register, a fixed frequency PWM signal can be generated
using the output compare and the counter overflow to define the pulse length.
75/175
ST72321M6 ST72321M9
16-BIT TIMER (Cont’d)
9.4.3.6 Pulse Width Modulation Mode
Pulse Width Modulation (PWM) mode enables the
generation of a signal with a frequency and pulse
length determined by the value of the OC1R and
OC2R registers.
Pulse Width Modulation mode uses the complete
Output Compare 1 function plus the OC2R register, and so this functionality can not be used when
PWM mode is activated.
In PWM mode, double buffering is implemented on
the output compare registers. Any new values written in the OC1R and OC2R registers are taken
into account only at the end of the PWM period
(OC2) to avoid spikes on the PWM output pin
(OCMP1).
Procedure
To use Pulse Width Modulation mode:
1. Load the OC2R register with the value corresponding to the period of the signal using the
formula in the opposite column.
2. Load the OC1R register with the value corresponding to the period of the pulse if
(OLVL1 = 0 and OLVL2 = 1) using the formula
in the opposite column.
3. Select the following in the CR1 register:
– Using the OLVL1 bit, select the level to be applied to the OCMP1 pin after a successful
comparison with the OC1R register.
– Using the OLVL2 bit, select the level to be applied to the OCMP1 pin after a successful
comparison with the OC2R register.
4. Select the following in the CR2 register:
– Set OC1E bit: the OCMP1 pin is then dedicated to the output compare 1 function.
– Set the PWM bit.
– Select the timer clock (CC[1:0]) (see Table 15
Clock Control Bits).
Pulse Width Modulation cycle
When
Counter
= OC1R
When
Counter
= OC2R
OCMP1 = OLVL1
OCMP1 = OLVL2
Counter is reset
to FFFCh
ICF1 bit is set
76/175
If OLVL1 = 1 and OLVL2 = 0 the length of the positive pulse is the difference between the OC2R and
OC1R registers.
If OLVL1 = OLVL2 a continuous signal will be
seen on the OCMP1 pin.
The OCiR register value required for a specific timing application can be calculated using the following formula:
OCiR Value =
t * fCPU
-5
PRESC
Where:
t
= Signal or pulse period (in seconds)
fCPU = CPU clock frequency (in hertz)
PRESC = Timer prescaler factor (2, 4 or 8 depending on CC[1:0] bits, see Table 15 Clock
Control Bits)
If the timer clock is an external clock the formula is:
OCiR = t * fEXT -5
Where:
t
= Signal or pulse period (in seconds)
fEXT
= External timer clock frequency (in hertz)
The Output Compare 2 event causes the counter
to be initialized to FFFCh (See Figure 49)
Notes:
1. After a write instruction to the OCiHR register,
the output compare function is inhibited until the
OCiLR register is also written.
2. The OCF1 and OCF2 bits cannot be set by
hardware in PWM mode therefore the Output
Compare interrupt is inhibited.
3. The ICF1 bit is set by hardware when the counter reaches the OC2R value and can produce a
timer interrupt if the ICIE bit is set and the I bit is
cleared.
4. In PWM mode the ICAP1 pin can not be used
to perform input capture because it is disconnected to the timer. The ICAP2 pin can be used
to perform input capture (ICF2 can be set and
IC2R can be loaded) but the user must take
care that the counter is reset each period and
ICF1 can also generates interrupt if ICIE is set.
5. When the Pulse Width Modulation (PWM) and
One Pulse mode (OPM) bits are both set, the
PWM mode is the only active one.
ST72321M6 ST72321M9
16-BIT TIMER (Cont’d)
9.4.4 Low Power Modes
Mode
WAIT
HALT
Description
No effect on 16-bit Timer.
Timer interrupts cause the device to exit from WAIT mode.
16-bit Timer registers are frozen.
In HALT mode, the counter stops counting until Halt mode is exited. Counting resumes from the previous
count when the MCU is woken up by an interrupt with “exit from HALT mode” capability or from the counter
reset value when the MCU is woken up by a RESET.
If an input capture event occurs on the ICAPi pin, the input capture detection circuitry is armed. Consequently, when the MCU is woken up by an interrupt with “exit from HALT mode” capability, the ICFi bit is set, and
the counter value present when exiting from HALT mode is captured into the ICiR register.
9.4.5 Interrupts
Event
Flag
Interrupt Event
Input Capture 1 event/Counter reset in PWM mode
Input Capture 2 event
Output Compare 1 event (not available in PWM mode)
Output Compare 2 event (not available in PWM mode)
Timer Overflow event
ICF1
ICF2
OCF1
OCF2
TOF
Enable
Control
Bit
Exit
from
Wait
Exit
from
Halt
Yes
No
ICIE
OCIE
TOIE
Note: The 16-bit Timer interrupt events are connected to the same interrupt vector (see Interrupts chapter). These events generate an interrupt if the corresponding Enable Control Bit is set and the interrupt
mask in the CC register is reset (RIM instruction).
9.4.6 Summary of Timer Modes
MODES
Input Capture (1 and/or 2)
Output Compare (1 and/or 2)
One Pulse Mode
PWM Mode
Input Capture 1
TIMER RESOURCES
Input Capture 2
Output Compare 1 Output Compare 2
Yes
Yes
Yes
Yes
No
Not Recommended1)
Not Recommended3)
No
Partially 2)
No
1) See note 4 in Section 9.4.3.5 One Pulse Mode
2) See note 5 in Section 9.4.3.5 One Pulse Mode
3) See note 4 in Section 9.4.3.6 Pulse Width Modulation Mode
77/175
ST72321M6 ST72321M9
16-BIT TIMER (Cont’d)
9.4.7 Register Description
Each Timer is associated with three control and
status registers, and with six pairs of data registers
(16-bit values) relating to the two input captures,
the two output compares, the counter and the alternate counter.
CONTROL REGISTER 1 (CR1)
Read/Write
Reset Value: 0000 0000 (00h)
7
0
Bit 4 = FOLV2 Forced Output Compare 2.
This bit is set and cleared by software.
0: No effect on the OCMP2 pin.
1: Forces the OLVL2 bit to be copied to the
OCMP2 pin, if the OC2E bit is set and even if
there is no successful comparison.
Bit 3 = FOLV1 Forced Output Compare 1.
This bit is set and cleared by software.
0: No effect on the OCMP1 pin.
1: Forces OLVL1 to be copied to the OCMP1 pin, if
the OC1E bit is set and even if there is no successful comparison.
ICIE OCIE TOIE FOLV2 FOLV1 OLVL2 IEDG1 OLVL1
Bit 7 = ICIE Input Capture Interrupt Enable.
0: Interrupt is inhibited.
1: A timer interrupt is generated whenever the
ICF1 or ICF2 bit of the SR register is set.
Bit 6 = OCIE Output Compare Interrupt Enable.
0: Interrupt is inhibited.
1: A timer interrupt is generated whenever the
OCF1 or OCF2 bit of the SR register is set.
Bit 5 = TOIE Timer Overflow Interrupt Enable.
0: Interrupt is inhibited.
1: A timer interrupt is enabled whenever the TOF
bit of the SR register is set.
78/175
Bit 2 = OLVL2 Output Level 2.
This bit is copied to the OCMP2 pin whenever a
successful comparison occurs with the OC2R register and OCxE is set in the CR2 register. This value is copied to the OCMP1 pin in One Pulse mode
and Pulse Width Modulation mode.
Bit 1 = IEDG1 Input Edge 1.
This bit determines which type of level transition
on the ICAP1 pin will trigger the capture.
0: A falling edge triggers the capture.
1: A rising edge triggers the capture.
Bit 0 = OLVL1 Output Level 1.
The OLVL1 bit is copied to the OCMP1 pin whenever a successful comparison occurs with the
OC1R register and the OC1E bit is set in the CR2
register.
ST72321M6 ST72321M9
16-BIT TIMER (Cont’d)
CONTROL REGISTER 2 (CR2)
Read/Write
Reset Value: 0000 0000 (00h)
7
0
OC1E OC2E OPM PWM CC1 CC0 IEDG2 EXEDG
Bit 7 = OC1E Output Compare 1 Pin Enable.
This bit is used only to output the signal from the
timer on the OCMP1 pin (OLV1 in Output Compare mode, both OLV1 and OLV2 in PWM and
one-pulse mode). Whatever the value of the OC1E
bit, the Output Compare 1 function of the timer remains active.
0: OCMP1 pin alternate function disabled (I/O pin
free for general-purpose I/O).
1: OCMP1 pin alternate function enabled.
Bit 6 = OC2E Output Compare 2 Pin Enable.
This bit is used only to output the signal from the
timer on the OCMP2 pin (OLV2 in Output Compare mode). Whatever the value of the OC2E bit,
the Output Compare 2 function of the timer remains active.
0: OCMP2 pin alternate function disabled (I/O pin
free for general-purpose I/O).
1: OCMP2 pin alternate function enabled.
Bit 5 = OPM One Pulse Mode.
0: One Pulse mode is not active.
1: One Pulse mode is active, the ICAP1 pin can be
used to trigger one pulse on the OCMP1 pin; the
active transition is given by the IEDG1 bit. The
length of the generated pulse depends on the
contents of the OC1R register.
79/175
Bit 4 = PWM Pulse Width Modulation.
0: PWM mode is not active.
1: PWM mode is active, the OCMP1 pin outputs a
programmable cyclic signal; the length of the
pulse depends on the value of OC1R register;
the period depends on the value of OC2R register.
Bit 3, 2 = CC[1:0] Clock Control.
The timer clock mode depends on these bits:
Table 15. Clock Control Bits
Timer Clock
fCPU / 4
fCPU / 2
fCPU / 8
External Clock (where available)
CC1
0
1
CC0
0
1
0
1
Note: If the external clock pin is not available, programming the external clock configuration stops
the counter.
Bit 1 = IEDG2 Input Edge 2.
This bit determines which type of level transition
on the ICAP2 pin will trigger the capture.
0: A falling edge triggers the capture.
1: A rising edge triggers the capture.
Bit 0 = EXEDG External Clock Edge.
This bit determines which type of level transition
on the external clock pin EXTCLK will trigger the
counter register.
0: A falling edge triggers the counter register.
1: A rising edge triggers the counter register.
ST72321M6 ST72321M9
16-BIT TIMER (Cont’d)
CONTROL/STATUS REGISTER (CSR)
Read/Write (bits 7:3 read only)
Reset Value: xxxx x0xx (xxh)
Note: Reading or writing the ACLR register does
not clear TOF.
7
ICF1
0
OCF1
TOF
ICF2
OCF2 TIMD
0
0
Bit 7 = ICF1 Input Capture Flag 1.
0: No input capture (reset value).
1: An input capture has occurred on the ICAP1 pin
or the counter has reached the OC2R value in
PWM mode. To clear this bit, first read the SR
register, then read or write the low byte of the
IC1R (IC1LR) register.
Bit 6 = OCF1 Output Compare Flag 1.
0: No match (reset value).
1: The content of the free running counter has
matched the content of the OC1R register. To
clear this bit, first read the SR register, then read
or write the low byte of the OC1R (OC1LR) register.
Bit 5 = TOF Timer Overflow Flag.
0: No timer overflow (reset value).
1: The free running counter rolled over from FFFFh
to 0000h. To clear this bit, first read the SR register, then read or write the low byte of the CR
(CLR) register.
80/175
Bit 4 = ICF2 Input Capture Flag 2.
0: No input capture (reset value).
1: An input capture has occurred on the ICAP2
pin. To clear this bit, first read the SR register,
then read or write the low byte of the IC2R
(IC2LR) register.
Bit 3 = OCF2 Output Compare Flag 2.
0: No match (reset value).
1: The content of the free running counter has
matched the content of the OC2R register. To
clear this bit, first read the SR register, then read
or write the low byte of the OC2R (OC2LR) register.
Bit 2 = TIMD Timer disable.
This bit is set and cleared by software. When set, it
freezes the timer prescaler and counter and disabled the output functions (OCMP1 and OCMP2
pins) to reduce power consumption. Access to the
timer registers is still available, allowing the timer
configuration to be changed, or the counter reset,
while it is disabled.
0: Timer enabled
1: Timer prescaler, counter and outputs disabled
Bits 1:0 = Reserved, must be kept cleared.
ST72321M6 ST72321M9
16-BIT TIMER (Cont’d)
INPUT CAPTURE 1 HIGH REGISTER (IC1HR)
Read Only
Reset Value: Undefined
This is an 8-bit read only register that contains the
high part of the counter value (transferred by the
input capture 1 event).
OUTPUT COMPARE 1 HIGH REGISTER
(OC1HR)
Read/Write
Reset Value: 1000 0000 (80h)
This is an 8-bit register that contains the high part
of the value to be compared to the CHR register.
7
0
7
0
MSB
LSB
MSB
LSB
INPUT CAPTURE 1 LOW REGISTER (IC1LR)
Read Only
Reset Value: Undefined
This is an 8-bit read only register that contains the
low part of the counter value (transferred by the input capture 1 event).
OUTPUT COMPARE 1 LOW REGISTER
(OC1LR)
Read/Write
Reset Value: 0000 0000 (00h)
This is an 8-bit register that contains the low part of
the value to be compared to the CLR register.
7
0
7
0
MSB
LSB
MSB
LSB
81/175
ST72321M6 ST72321M9
16-BIT TIMER (Cont’d)
OUTPUT COMPARE 2 HIGH REGISTER
(OC2HR)
Read/Write
Reset Value: 1000 0000 (80h)
This is an 8-bit register that contains the high part
of the value to be compared to the CHR register.
ALTERNATE COUNTER HIGH REGISTER
(ACHR)
Read Only
Reset Value: 1111 1111 (FFh)
This is an 8-bit register that contains the high part
of the counter value.
7
0
7
0
MSB
LSB
MSB
LSB
OUTPUT COMPARE 2 LOW REGISTER
(OC2LR)
Read/Write
Reset Value: 0000 0000 (00h)
This is an 8-bit register that contains the low part of
the value to be compared to the CLR register.
7
0
MSB
LSB
COUNTER HIGH REGISTER (CHR)
Read Only
Reset Value: 1111 1111 (FFh)
This is an 8-bit register that contains the high part
of the counter value.
7
0
MSB
LSB
COUNTER LOW REGISTER (CLR)
Read Only
Reset Value: 1111 1100 (FCh)
This is an 8-bit register that contains the low part of
the counter value. A write to this register resets the
counter. An access to this register after accessing
the CSR register clears the TOF bit.
7
0
MSB
LSB
82/175
ALTERNATE COUNTER LOW REGISTER
(ACLR)
Read Only
Reset Value: 1111 1100 (FCh)
This is an 8-bit register that contains the low part of
the counter value. A write to this register resets the
counter. An access to this register after an access
to CSR register does not clear the TOF bit in the
CSR register.
7
0
MSB
LSB
INPUT CAPTURE 2 HIGH REGISTER (IC2HR)
Read Only
Reset Value: Undefined
This is an 8-bit read only register that contains the
high part of the counter value (transferred by the
Input Capture 2 event).
7
0
MSB
LSB
INPUT CAPTURE 2 LOW REGISTER (IC2LR)
Read Only
Reset Value: Undefined
This is an 8-bit read only register that contains the
low part of the counter value (transferred by the Input Capture 2 event).
7
0
MSB
LSB
ST72321M6 ST72321M9
16-BIT TIMER (Cont’d)
Table 16. 16-Bit Timer Register Map and Reset Values
Address
(Hex.)
Register
Label
7
6
5
4
3
2
1
0
Timer A: 32
Timer B: 42
Timer A: 31
Timer B: 41
Timer A: 33
Timer B: 43
Timer A: 34
Timer B: 44
Timer A: 35
Timer B: 45
Timer A: 36
Timer B: 46
Timer A: 37
Timer B: 47
Timer A: 3E
Timer B: 4E
Timer A: 3F
Timer B: 4F
Timer A: 38
Timer B: 48
Timer A: 39
Timer B: 49
Timer A: 3A
Timer B: 4A
Timer A: 3B
Timer B: 4B
Timer A: 3C
Timer B: 4C
Timer A: 3D
Timer B: 4D
CR1
Reset Value
CR2
Reset Value
CSR
Reset Value
IC1HR
Reset Value
IC1LR
Reset Value
OC1HR
Reset Value
OC1LR
Reset Value
OC2HR
Reset Value
OC2LR
Reset Value
CHR
Reset Value
CLR
Reset Value
ACHR
Reset Value
ACLR
Reset Value
IC2HR
Reset Value
IC2LR
Reset Value
ICIE
0
OC1E
0
ICF1
x
MSB
x
MSB
x
MSB
1
MSB
0
MSB
1
MSB
0
MSB
1
MSB
1
MSB
1
MSB
1
MSB
x
MSB
x
OCIE
0
OC2E
0
OCF1
x
TOIE
0
OPM
0
TOF
x
FOLV2
0
PWM
0
ICF2
x
FOLV1
0
CC1
0
OCF2
x
OLVL2
0
CC0
0
TIMD
0
IEDG1
0
IEDG2
0
x
x
x
x
x
x
x
x
x
x
x
x
x
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
0
1
1
1
1
1
1
1
1
1
1
1
0
x
x
x
x
x
x
x
x
x
x
x
x
OLVL1
0
EXEDG
0
x
LSB
x
LSB
x
LSB
0
LSB
0
LSB
0
LSB
0
LSB
1
LSB
0
LSB
1
LSB
0
LSB
x
LSB
x
Related Documentation
AN 973: SCI software communications using 16bit timer
AN 974: Real-Time Clock with ST7 Timer Output
Compare
AN 976: Driving a buzzer through the ST7 Timer
PWM function
83/175
AN1041: Using ST7 PWM signal to generate analog input (sinusoid)
AN1046: UART emulation software
AN1078: PWM duty cycle switch implementing
true 0 or 100 per cent duty cycle
AN1504: Starting a PWM signal directly at high
level using the ST7 16-Bit timer
ST72321M6 ST72321M9
9.5 SERIAL PERIPHERAL INTERFACE (SPI)
9.5.1 Introduction
The Serial Peripheral Interface (SPI) allows fullduplex, synchronous, serial communication with
external devices. An SPI system may consist of a
master and one or more slaves however the SPI
interface can not be a master in a multi-master
system.
9.5.2 Main Features
■ Full duplex synchronous transfers (on 3 lines)
■ Simplex synchronous transfers (on 2 lines)
■ Master or slave operation
■ Six master mode frequencies (fCPU/4 max.)
■ fCPU/2 max. slave mode frequency (see note)
■ SS Management by software or hardware
■ Programmable clock polarity and phase
■ End of transfer interrupt flag
■ Write collision, Master Mode Fault and Overrun
flags
Note: In slave mode, continuous transmission is
not possible at maximum frequency due to the
software overhead for clearing status flags and to
initiate the next transmission sequence.
9.5.3 General Description
Figure 50 shows the serial peripheral interface
(SPI) block diagram. There are 3 registers:
– SPI Control Register (SPICR)
– SPI Control/Status Register (SPICSR)
– SPI Data Register (SPIDR)
The SPI is connected to external devices through
4 pins:
– MISO: Master In / Slave Out data
– MOSI: Master Out / Slave In data
– SCK: Serial Clock out by SPI masters and input by SPI slaves
Figure 50. Serial Peripheral Interface Block Diagram
Data/Address Bus
SPIDR
Read
Interrupt
request
Read Buffer
MOSI
MISO
8-Bit Shift Register
SPICSR
7
SPIF WCOL OVR MODF
SOD
bit
SS
SPI
STATE
CONTROL
7
SPIE
MASTER
CONTROL
SERIAL CLOCK
GENERATOR
84/175
SOD SSM
SSI
Write
SCK
SS
0
0
1
0
SPICR
0
SPE SPR2 MSTR CPOL CPHA SPR1 SPR0
ST72321M6 ST72321M9
SERIAL PERIPHERAL INTERFACE (Cont’d)
– SS: Slave select:
This input signal acts as a ‘chip select’ to let
the SPI master communicate with slaves individually and to avoid contention on the data
lines. Slave SS inputs can be driven by standard I/O ports on the master MCU.
9.5.3.1 Functional Description
A basic example of interconnections between a
single master and a single slave is illustrated in
Figure 51.
The MOSI pins are connected together and the
MISO pins are connected together. In this way
data is transferred serially between master and
slave (most significant bit first).
The communication is always initiated by the master. When the master device transmits data to a
slave device via MOSI pin, the slave device responds by sending data to the master device via
the MISO pin. This implies full duplex communication with both data out and data in synchronized
with the same clock signal (which is provided by
the master device via the SCK pin).
To use a single data line, the MISO and MOSI pins
must be connected at each node ( in this case only
simplex communication is possible).
Four possible data/clock timing relationships may
be chosen (see Figure 54) but master and slave
must be programmed with the same timing mode.
Figure 51. Single Master/ Single Slave Application
SLAVE
MASTER
MSBit
LSBit
8-BIT SHIFT REGISTER
SPI
CLOCK
GENERATOR
MSBit
MISO
MISO
MOSI
MOSI
SCK
SS
LSBit
8-BIT SHIFT REGISTER
SCK
+5V
SS
Not used if SS is managed
by software
85/175
ST72321M6 ST72321M9
SERIAL PERIPHERAL INTERFACE (Cont’d)
9.5.3.2 Slave Select Management
As an alternative to using the SS pin to control the
Slave Select signal, the application can choose to
manage the Slave Select signal by software. This
is configured by the SSM bit in the SPICSR register (see Figure 53)
In software management, the external SS pin is
free for other application uses and the internal SS
signal level is driven by writing to the SSI bit in the
SPICSR register.
In Master mode:
– SS internal must be held high continuously
In Slave Mode:
There are two cases depending on the data/clock
timing relationship (see Figure 52):
If CPHA=1 (data latched on 2nd clock edge):
– SS internal must be held low during the entire
transmission. This implies that in single slave
applications the SS pin either can be tied to
VSS, or made free for standard I/O by managing the SS function by software (SSM= 1 and
SSI=0 in the in the SPICSR register)
If CPHA=0 (data latched on 1st clock edge):
– SS internal must be held low during byte
transmission and pulled high between each
byte to allow the slave to write to the shift register. If SS is not pulled high, a Write Collision
error will occur when the slave writes to the
shift register (see Section 9.5.5.3).
Figure 52. Generic SS Timing Diagram
MOSI/MISO
Byte 1
Byte 2
Master SS
Slave SS
(if CPHA=0)
Slave SS
(if CPHA=1)
Figure 53. Hardware/Software Slave Select Management
SSM bit
86/175
SSI bit
1
SS external pin
0
SS internal
Byte 3
ST72321M6 ST72321M9
SERIAL PERIPHERAL INTERFACE (Cont’d)
9.5.3.3 Master Mode Operation
In master mode, the serial clock is output on the
SCK pin. The clock frequency, polarity and phase
are configured by software (refer to the description
of the SPICSR register).
Note: The idle state of SCK must correspond to
the polarity selected in the SPICSR register (by
pulling up SCK if CPOL=1 or pulling down SCK if
CPOL=0).
To operate the SPI in master mode, perform the
following steps in order (if the SPICSR register is
not written first, the SPICR register setting (MSTR
bit) may be not taken into account):
1. Write to the SPICR register:
– Select the clock frequency by configuring the
SPR[2:0] bits.
– Select the clock polarity and clock phase by
configuring the CPOL and CPHA bits. Figure
54 shows the four possible configurations.
Note: The slave must have the same CPOL
and CPHA settings as the master.
2. Write to the SPICSR register:
– Either set the SSM bit and set the SSI bit or
clear the SSM bit and tie the SS pin high for
the complete byte transmit sequence.
3. Write to the SPICR register:
– Set the MSTR and SPE bits
Note: MSTR and SPE bits remain set only if
SS is high).
The transmit sequence begins when software
writes a byte in the SPIDR register.
9.5.3.4 Master Mode Transmit Sequence
When software writes to the SPIDR register, the
data byte is loaded into the 8-bit shift register and
then shifted out serially to the MOSI pin most significant bit first.
When data transfer is complete:
– The SPIF bit is set by hardware
– An interrupt request is generated if the SPIE
bit is set and the interrupt mask in the CCR
register is cleared.
Clearing the SPIF bit is performed by the following
software sequence:
1. An access to the SPICSR register while the
SPIF bit is set
2. A read to the SPIDR register.
87/175
Note: While the SPIF bit is set, all writes to the
SPIDR register are inhibited until the SPICSR register is read.
9.5.3.5 Slave Mode Operation
In slave mode, the serial clock is received on the
SCK pin from the master device.
To operate the SPI in slave mode:
1. Write to the SPICSR register to perform the following actions:
– Select the clock polarity and clock phase by
configuring the CPOL and CPHA bits (see
Figure 54).
Note: The slave must have the same CPOL
and CPHA settings as the master.
– Manage the SS pin as described in Section
9.5.3.2 and Figure 52. If CPHA=1 SS must be
held low continuously. If CPHA=0 SS must be
held low during byte transmission and pulled
up between each byte to let the slave write in
the shift register.
2. Write to the SPICR register to clear the MSTR
bit and set the SPE bit to enable the SPI I/O
functions.
9.5.3.6 Slave Mode Transmit Sequence
When software writes to the SPIDR register, the
data byte is loaded into the 8-bit shift register and
then shifted out serially to the MISO pin most significant bit first.
The transmit sequence begins when the slave device receives the clock signal and the most significant bit of the data on its MOSI pin.
When data transfer is complete:
– The SPIF bit is set by hardware
– An interrupt request is generated if SPIE bit is
set and interrupt mask in the CCR register is
cleared.
Clearing the SPIF bit is performed by the following
software sequence:
1. An access to the SPICSR register while the
SPIF bit is set.
2. A write or a read to the SPIDR register.
Notes: While the SPIF bit is set, all writes to the
SPIDR register are inhibited until the SPICSR register is read.
The SPIF bit can be cleared during a second
transmission; however, it must be cleared before
the second SPIF bit in order to prevent an Overrun
condition (see Section 9.5.5.2).
ST72321M6 ST72321M9
SERIAL PERIPHERAL INTERFACE (Cont’d)
9.5.4 Clock Phase and Clock Polarity
Four possible timing relationships may be chosen
by software, using the CPOL and CPHA bits (See
Figure 54).
Note: The idle state of SCK must correspond to
the polarity selected in the SPICSR register (by
pulling up SCK if CPOL=1 or pulling down SCK if
CPOL=0).
The combination of the CPOL clock polarity and
CPHA (clock phase) bits selects the data capture
clock edge
Figure 54, shows an SPI transfer with the four
combinations of the CPHA and CPOL bits. The diagram may be interpreted as a master or slave
timing diagram where the SCK pin, the MISO pin,
the MOSI pin are directly connected between the
master and the slave device.
Note: If CPOL is changed at the communication
byte boundaries, the SPI must be disabled by resetting the SPE bit.
Figure 54. Data Clock Timing Diagram
CPHA =1
SCK
(CPOL = 1)
SCK
(CPOL = 0)
MISO
(from master)
MOSI
(from slave)
MSBit
Bit 6
Bit 5
Bit 4
Bit3
Bit 2
Bit 1
LSBit
MSBit
Bit 6
Bit 5
Bit 4
Bit3
Bit 2
Bit 1
LSBit
SS
(to slave)
CAPTURE STROBE
CPHA =0
SCK
(CPOL = 1)
SCK
(CPOL = 0)
MISO
(from master)
MOSI
(from slave)
MSBit
MSBit
Bit 6
Bit 5
Bit 4
Bit3
Bit 2
Bit 1
LSBit
Bit 6
Bit 5
Bit 4
Bit3
Bit 2
Bit 1
LSBit
SS
(to slave)
CAPTURE STROBE
Note: This figure should not be used as a replacement for parametric information.
Refer to the Electrical Characteristics chapter.
88/175
ST72321M6 ST72321M9
SERIAL PERIPHERAL INTERFACE (Cont’d)
9.5.5 Error Flags
9.5.5.1 Master Mode Fault (MODF)
Master mode fault occurs when the master device
has its SS pin pulled low.
When a Master mode fault occurs:
– The MODF bit is set and an SPI interrupt request is generated if the SPIE bit is set.
– The SPE bit is reset. This blocks all output
from the device and disables the SPI peripheral.
– The MSTR bit is reset, thus forcing the device
into slave mode.
Clearing the MODF bit is done through a software
sequence:
1. A read access to the SPICSR register while the
MODF bit is set.
2. A write to the SPICR register.
Notes: To avoid any conflicts in an application
with multiple slaves, the SS pin must be pulled
high during the MODF bit clearing sequence. The
SPE and MSTR bits may be restored to their original state during or after this clearing sequence.
Hardware does not allow the user to set the SPE
and MSTR bits while the MODF bit is set except in
the MODF bit clearing sequence.
9.5.5.2 Overrun Condition (OVR)
An overrun condition occurs, when the master device has sent a data byte and the slave device has
not cleared the SPIF bit issued from the previously
transmitted byte.
When an Overrun occurs:
– The OVR bit is set and an interrupt request is
generated if the SPIE bit is set.
In this case, the receiver buffer contains the byte
sent after the SPIF bit was last cleared. A read to
the SPIDR register returns this byte. All other
bytes are lost.
The OVR bit is cleared by reading the SPICSR
register.
9.5.5.3 Write Collision Error (WCOL)
A write collision occurs when the software tries to
write to the SPIDR register while a data transfer is
taking place with an external device. When this
happens, the transfer continues uninterrupted;
and the software write will be unsuccessful.
Write collisions can occur both in master and slave
mode. See also Section 9.5.3.2 Slave Select Management.
Note: a "read collision" will never occur since the
received data byte is placed in a buffer in which
access is always synchronous with the MCU operation.
The WCOL bit in the SPICSR register is set if a
write collision occurs.
No SPI interrupt is generated when the WCOL bit
is set (the WCOL bit is a status flag only).
Clearing the WCOL bit is done through a software
sequence (see Figure 55).
Figure 55. Clearing the WCOL bit (Write Collision Flag) Software Sequence
Clearing sequence after SPIF = 1 (end of a data byte transfer)
1st Step
Read SPICSR
RESULT
2nd Step
Read SPIDR
SPIF =0
WCOL=0
Clearing sequence before SPIF = 1 (during a data byte transfer)
1st Step
Read SPICSR
RESULT
2nd Step
89/175
Read SPIDR
WCOL=0
Note: Writing to the SPIDR register instead of reading it does not
reset the WCOL bit
ST72321M6 ST72321M9
SERIAL PERIPHERAL INTERFACE (Cont’d)
9.5.5.4 Single Master Systems
A typical single master system may be configured,
using an MCU as the master and four MCUs as
slaves (see Figure 56).
The master device selects the individual slave devices by using four pins of a parallel port to control
the four SS pins of the slave devices.
The SS pins are pulled high during reset since the
master device ports will be forced to be inputs at
that time, thus disabling the slave devices.
Note: To prevent a bus conflict on the MISO line
the master allows only one active slave device
during a transmission.
For more security, the slave device may respond
to the master with the received data byte. Then the
master will receive the previous byte back from the
slave device if all MISO and MOSI pins are connected and the slave has not written to its SPIDR
register.
Other transmission security methods can use
ports for handshake lines or data bytes with command fields.
Figure 56. Single Master / Multiple Slave Configuration
SS
SCK
Slave
MCU
Slave
MCU
MOSI MISO
MOSI MISO
SCK
Master
MCU
5V
90/175
SS
Ports
MOSI MISO
SS
SS
SCK
SS
SCK
Slave
MCU
SCK
Slave
MCU
MOSI MISO
MOSI MISO
ST72321M6 ST72321M9
SERIAL PERIPHERAL INTERFACE (Cont’d)
9.5.6 Low Power Modes
Mode
Wait
Halt
Description
No effect on SPI.
SPI interrupt events cause the device to exit
from Wait mode.
SPI registers are frozen.
In Halt mode, the SPI is inactive. SPI operation resumes when the MCU is woken up by
an interrupt with “exit from Halt mode” capability. The data received is subsequently read
from the SPIDR register when the software is
running (interrupt vector fetching). If several
data are received before the wake-up event,
then an overrun error is generated. This error
can be detected after the fetch of the interrupt routine that woke up the device.
Note: When waking up from Halt mode, if the SPI
remains in Slave mode, it is recommended to perform an extra communications cycle to bring the
SPI from Halt mode state to normal state. If the
SPI exits from Slave mode, it returns to normal
state immediately.
Caution: The SPI can wake up the ST7 from Halt
mode only if the Slave Select signal (external SS
pin or the SSI bit in the SPICSR register) is low
when the ST7 enters Halt mode. So if Slave selection is configured as external (see Section
9.5.3.2), make sure the master drives a low level
on the SS pin when the slave enters Halt mode.
9.5.7 Interrupts
Interrupt Event
9.5.6.1 Using the SPI to wakeup the MCU from
Halt mode
In slave configuration, the SPI is able to wakeup
the ST7 device from Halt mode through a SPIF interrupt. The data received is subsequently read
from the SPIDR register when the software is running (interrupt vector fetch). If multiple data transfers have been performed before software clears
the SPIF bit, then the OVR bit is set by hardware.
91/175
SPI End of Transfer
Event
Master Mode Fault
Event
Overrun Error
Event
Flag
Enable
Control
Bit
SPIF
MODF
OVR
SPIE
Exit
from
Wait
Exit
from
Halt
Yes
Yes
Yes
No
Yes
No
Note: The SPI interrupt events are connected to
the same interrupt vector (see Interrupts chapter).
They generate an interrupt if the corresponding
Enable Control Bit is set and the interrupt mask in
ST72321M6 ST72321M9
SERIAL PERIPHERAL INTERFACE (Cont’d)
9.5.8 Register Description
CONTROL REGISTER (SPICR)
Read/Write
Reset Value: 0000 xxxx (0xh)
7
SPIE
0
SPE
SPR2
MSTR
CPOL
CPHA
SPR1
SPR0
Bit 7 = SPIE Serial Peripheral Interrupt Enable.
This bit is set and cleared by software.
0: Interrupt is inhibited
1: An SPI interrupt is generated whenever
SPIF=1, MODF=1 or OVR=1 in the SPICSR
register
Bit 6 = SPE Serial Peripheral Output Enable.
This bit is set and cleared by software. It is also
cleared by hardware when, in master mode, SS=0
(see Section 9.5.5.1 Master Mode Fault (MODF)).
The SPE bit is cleared by reset, so the SPI peripheral is not initially connected to the external pins.
0: I/O pins free for general purpose I/O
1: SPI I/O pin alternate functions enabled
Bit 5 = SPR2 Divider Enable.
This bit is set and cleared by software and is
cleared by reset. It is used with the SPR[1:0] bits to
set the baud rate. Refer to Table 17 SPI Master
mode SCK Frequency.
0: Divider by 2 enabled
1: Divider by 2 disabled
Note: This bit has no effect in slave mode.
Bit 4 = MSTR Master Mode.
This bit is set and cleared by software. It is also
cleared by hardware when, in master mode, SS=0
(see Section 9.5.5.1 Master Mode Fault (MODF)).
0: Slave mode
1: Master mode. The function of the SCK pin
changes from an input to an output and the functions of the MISO and MOSI pins are reversed.
92/175
Bit 3 = CPOL Clock Polarity.
This bit is set and cleared by software. This bit determines the idle state of the serial Clock. The
CPOL bit affects both the master and slave
modes.
0: SCK pin has a low level idle state
1: SCK pin has a high level idle state
Note: If CPOL is changed at the communication
byte boundaries, the SPI must be disabled by resetting the SPE bit.
Bit 2 = CPHA Clock Phase.
This bit is set and cleared by software.
0: The first clock transition is the first data capture
edge.
1: The second clock transition is the first capture
edge.
Note: The slave must have the same CPOL and
CPHA settings as the master.
Bits 1:0 = SPR[1:0] Serial Clock Frequency.
These bits are set and cleared by software. Used
with the SPR2 bit, they select the baud rate of the
SPI serial clock SCK output by the SPI in master
mode.
Note: These 2 bits have no effect in slave mode.
Table 17. SPI Master mode SCK Frequency
Serial Clock
SPR2
SPR1
SPR0
fCPU/4
1
0
0
fCPU/8
0
0
0
fCPU/16
0
0
1
fCPU/32
1
1
0
fCPU/64
0
1
0
fCPU/128
0
1
1
ST72321M6 ST72321M9
SERIAL PERIPHERAL INTERFACE (Cont’d)
CONTROL/STATUS REGISTER (SPICSR)
Read/Write (some bits Read Only)
Reset Value: 0000 0000 (00h)
7
SPIF
Bit 3 = Reserved, must be kept cleared.
0
WCOL
OVR
MODF
-
SOD
SSM
SSI
Bit 7 = SPIF Serial Peripheral Data Transfer Flag
(Read only).
This bit is set by hardware when a transfer has
been completed. An interrupt is generated if
SPIE=1 in the SPICR register. It is cleared by a
software sequence (an access to the SPICSR
register followed by a write or a read to the
SPIDR register).
0: Data transfer is in progress or the flag has been
cleared.
1: Data transfer between the device and an external device has been completed.
Note: While the SPIF bit is set, all writes to the
SPIDR register are inhibited until the SPICSR register is read.
Bit 6 = WCOL Write Collision status (Read only).
This bit is set by hardware when a write to the
SPIDR register is done during a transmit sequence. It is cleared by a software sequence (see
Figure 55).
0: No write collision occurred
1: A write collision has been detected
Bit 2 = SOD SPI Output Disable.
This bit is set and cleared by software. When set, it
disables the alternate function of the SPI output
(MOSI in master mode / MISO in slave mode)
0: SPI output enabled (if SPE=1)
1: SPI output disabled
Bit 1 = SSM SS Management.
This bit is set and cleared by software. When set, it
disables the alternate function of the SPI SS pin
and uses the SSI bit value instead. See Section
9.5.3.2 Slave Select Management.
0: Hardware management (SS managed by external pin)
1: Software management (internal SS signal controlled by SSI bit. External SS pin free for general-purpose I/O)
Bit 0 = SSI SS Internal Mode.
This bit is set and cleared by software. It acts as a
‘chip select’ by controlling the level of the SS slave
select signal when the SSM bit is set.
0 : Slave selected
1 : Slave deselected
DATA I/O REGISTER (SPIDR)
Read/Write
Reset Value: Undefined
7
Bit 5 = OVR SPI Overrun error (Read only).
This bit is set by hardware when the byte currently
being received in the shift register is ready to be
transferred into the SPIDR register while SPIF = 1
(See Section 9.5.5.2). An interrupt is generated if
SPIE = 1 in SPICR register. The OVR bit is cleared
by software reading the SPICSR register.
0: No overrun error
1: Overrun error detected
Bit 4 = MODF Mode Fault flag (Read only).
This bit is set by hardware when the SS pin is
pulled low in master mode (see Section 9.5.5.1
Master Mode Fault (MODF)). An SPI interrupt can
be generated if SPIE=1 in the SPICSR register.
This bit is cleared by a software sequence (An access to the SPICR register while MODF=1 followed by a write to the SPICR register).
0: No master mode fault detected
1: A fault in master mode has been detected
93/175
D7
0
D6
D5
D4
D3
D2
D1
D0
The SPIDR register is used to transmit and receive
data on the serial bus. In a master device, a write
to this register will initiate transmission/reception
of another byte.
Notes: During the last clock cycle the SPIF bit is
set, a copy of the received data byte in the shift
register is moved to a buffer. When the user reads
the serial peripheral data I/O register, the buffer is
actually being read.
While the SPIF bit is set, all writes to the SPIDR
register are inhibited until the SPICSR register is
read.
Warning: A write to the SPIDR register places
data directly into the shift register for transmission.
A read to the SPIDR register returns the value located in the buffer and not the content of the shift
register (see Figure 50).
ST72321M6 ST72321M9
SERIAL PERIPHERAL INTERFACE (Cont’d)
Table 18. SPI Register Map and Reset Values
Address
(Hex.)
0021h
0022h
0023h
94/175
Register
Label
7
6
5
4
3
2
1
0
SPIDR
Reset Value
SPICR
Reset Value
SPICSR
Reset Value
MSB
x
SPIE
0
SPIF
0
x
SPE
0
WCOL
0
x
SPR2
0
OR
0
x
MSTR
0
MODF
0
x
CPOL
x
x
CPHA
x
SOD
0
x
SPR1
x
SSM
0
LSB
x
SPR0
x
SSI
0
0
ST72321M6 ST72321M9
9.6 SERIAL COMMUNICATIONS INTERFACE (SCI)
9.6.1 Introduction
The Serial Communications Interface (SCI) offers
a flexible means of full-duplex data exchange with
external equipment requiring an industry standard
NRZ asynchronous serial data format. The SCI offers a very wide range of baud rates using two
baud rate generator systems.
9.6.2 Main Features
■ Full duplex, asynchronous communications
■ NRZ standard format (Mark/Space)
■ Dual baud rate generator systems
■ Independently
programmable transmit and
receive baud rates up to 500 Kbaud
■ Programmable data word length (8 or 9 bits)
■ Receive buffer full, Transmit buffer empty and
End of Transmission flags
■ Two receiver wake-up modes:
– Address bit (MSB)
– Idle line
■ Muting function for multiprocessor configurations
■ Separate enable bits for Transmitter and
Receiver
■ Four error detection flags:
– Overrun error
– Noise error
– Frame error
– Parity error
■ Five interrupt sources with flags:
– Transmit data register empty
– Transmission complete
– Receive data register full
– Idle line received
– Overrun error detected
■ Parity control:
– Transmits parity bit
– Checks parity of received data byte
■ Reduced power consumption mode
95/175
9.6.3 General Description
The interface is externally connected to another
device by two pins (see Figure 58):
– TDO: Transmit Data Output. When the transmitter and the receiver are disabled, the output pin
returns to its I/O port configuration. When the
transmitter and/or the receiver are enabled and
nothing is to be transmitted, the TDO pin is at
high level.
– RDI: Receive Data Input is the serial data input.
Oversampling techniques are used for data recovery by discriminating between valid incoming
data and noise.
Through these pins, serial data is transmitted and
received as frames comprising:
– An Idle Line prior to transmission or reception
– A start bit
– A data word (8 or 9 bits) least significant bit first
– A Stop bit indicating that the frame is complete
This interface uses two types of baud rate generator:
– A conventional type for commonly-used baud
rates
– An extended type with a prescaler offering a very
wide range of baud rates even with non-standard
oscillator frequencies
ST72321M6 ST72321M9
SERIAL COMMUNICATIONS INTERFACE (Cont’d)
Figure 57. SCI Block Diagram
Write
Read
(DATA REGISTER) DR
Received Data Register (RDR)
Transmit Data Register (TDR)
TDO
Received Shift Register
Transmit Shift Register
RDI
CR1
R8
TRANSMIT
WAKE
UP
CONTROL
UNIT
T8
SCID
M WAKE PCE PS
PIE
RECEIVER
CLOCK
RECEIVER
CONTROL
CR2
SR
TIE TCIE RIE
ILIE
TE
RE RWU SBK
TDRE TC RDRF IDLE OR
NF
FE
SCI
INTERRUPT
CONTROL
TRANSMITTER
CLOCK
TRANSMITTER RATE
fCPU
CONTROL
/16
/PR
BRR
SCP1 SCP0 SCT2 SCT1 SCT0 SCR2 SCR1SCR0
RECEIVER RATE
CONTROL
CONVENTIONAL BAUD RATE GENERATOR
96/175
PE
ST72321M6 ST72321M9
SERIAL COMMUNICATIONS INTERFACE (Cont’d)
9.6.4 Functional Description
The block diagram of the Serial Control Interface,
is shown in Figure 57 It contains six dedicated registers:
– Two control registers (SCICR1 & SCICR2)
– A status register (SCISR)
– A baud rate register (SCIBRR)
– An extended prescaler receiver register (SCIERPR)
– An extended prescaler transmitter register (SCIETPR)
Refer to the register descriptions in Section
9.6.7for the definitions of each bit.
9.6.4.1 Serial Data Format
Word length may be selected as being either 8 or 9
bits by programming the M bit in the SCICR1 register (see Figure 57).
The TDO pin is in low state during the start bit.
The TDO pin is in high state during the stop bit.
An Idle character is interpreted as an entire frame
of “1”s followed by the start bit of the next frame
which contains data.
A Break character is interpreted on receiving “0”s
for some multiple of the frame period. At the end of
the last break frame the transmitter inserts an extra “1” bit to acknowledge the start bit.
Transmission and reception are driven by their
own baud rate generator.
Figure 58. Word Length Programming
9-bit Word length (M bit is set)
Possible
Parity
Bit
Data Frame
Start
Bit
Bit0
Bit2
Bit1
Bit3
Bit4
Bit5
Bit6
Start
Bit
Break Frame
Extra
‘1’
Possible
Parity
Bit
Data Frame
97/175
Bit0
Bit8
Next
Stop Start
Bit
Bit
Idle Frame
8-bit Word length (M bit is reset)
Start
Bit
Bit7
Next Data Frame
Bit1
Bit2
Bit3
Bit4
Bit5
Bit6
Bit7
Start
Bit
Next Data Frame
Stop
Bit
Next
Start
Bit
Idle Frame
Start
Bit
Break Frame
Extra Start
Bit
‘1’
ST72321M6 ST72321M9
SERIAL COMMUNICATIONS INTERFACE (Cont’d)
9.6.4.2 Transmitter
The transmitter can send data words of either 8 or
9 bits depending on the M bit status. When the M
bit is set, word length is 9 bits and the 9th bit (the
MSB) has to be stored in the T8 bit in the SCICR1
register.
Character Transmission
During an SCI transmission, data shifts out least
significant bit first on the TDO pin. In this mode,
the SCIDR register consists of a buffer (TDR) between the internal bus and the transmit shift register (see Figure 57).
Procedure
– Select the M bit to define the word length.
– Select the desired baud rate using the SCIBRR
and the SCIETPR registers.
– Set the TE bit to assign the TDO pin to the alternate function and to send a idle frame as first
transmission.
– Access the SCISR register and write the data to
send in the SCIDR register (this sequence clears
the TDRE bit). Repeat this sequence for each
data to be transmitted.
Clearing the TDRE bit is always performed by the
following software sequence:
1. An access to the SCISR register
2. A write to the SCIDR register
The TDRE bit is set by hardware and it indicates:
– The TDR register is empty.
– The data transfer is beginning.
– The next data can be written in the SCIDR register without overwriting the previous data.
This flag generates an interrupt if the TIE bit is set
and the I bit is cleared in the CCR register.
When a transmission is taking place, a write instruction to the SCIDR register stores the data in
the TDR register and which is copied in the shift
register at the end of the current transmission.
When no transmission is taking place, a write instruction to the SCIDR register places the data directly in the shift register, the data transmission
starts, and the TDRE bit is immediately set.
98/175
When a frame transmission is complete (after the
stop bit) the TC bit is set and an interrupt is generated if the TCIE is set and the I bit is cleared in the
CCR register.
Clearing the TC bit is performed by the following
software sequence:
1. An access to the SCISR register
2. A write to the SCIDR register
Note: The TDRE and TC bits are cleared by the
same software sequence.
Break Characters
Setting the SBK bit loads the shift register with a
break character. The break frame length depends
on the M bit (see Figure 58).
As long as the SBK bit is set, the SCI send break
frames to the TDO pin. After clearing this bit by
software the SCI insert a logic 1 bit at the end of
the last break frame to guarantee the recognition
of the start bit of the next frame.
Idle Characters
Setting the TE bit drives the SCI to send an idle
frame before the first data frame.
Clearing and then setting the TE bit during a transmission sends an idle frame after the current word.
Note: Resetting and setting the TE bit causes the
data in the TDR register to be lost. Therefore the
best time to toggle the TE bit is when the TDRE bit
is set, that is, before writing the next byte in the
SCIDR.
ST72321M6 ST72321M9
SERIAL COMMUNICATIONS INTERFACE (Cont’d)
9.6.4.3 Receiver
The SCI can receive data words of either 8 or 9
bits. When the M bit is set, word length is 9 bits
and the MSB is stored in the R8 bit in the SCICR1
register.
Character reception
During a SCI reception, data shifts in least significant bit first through the RDI pin. In this mode, the
SCIDR register consists or a buffer (RDR) between the internal bus and the received shift register (see Figure 57).
Procedure
– Select the M bit to define the word length.
– Select the desired baud rate using the SCIBRR
and the SCIERPR registers.
– Set the RE bit, this enables the receiver which
begins searching for a start bit.
When a character is received:
– The RDRF bit is set. It indicates that the content
of the shift register is transferred to the RDR.
– An interrupt is generated if the RIE bit is set and
the I bit is cleared in the CCR register.
– The error flags can be set if a frame error, noise
or an overrun error has been detected during reception.
Clearing the RDRF bit is performed by the following
software sequence done by:
1. An access to the SCISR register
2. A read to the SCIDR register.
The RDRF bit must be cleared before the end of the
reception of the next character to avoid an overrun
error.
Break Character
When a break character is received, the SCI handles it as a framing error.
Idle Character
When a idle frame is detected, there is the same
procedure as a data received character plus an interrupt if the ILIE bit is set and the I bit is cleared in
the CCR register.
Overrun Error
An overrun error occurs when a character is received when RDRF has not been reset. Data can
not be transferred from the shift register to the
99/175
RDR register as long as the RDRF bit is not
cleared.
When an overrun error occurs:
– The OR bit is set.
– The RDR content is not lost.
– The shift register is overwritten.
– An interrupt is generated if the RIE bit is set and
the I bit is cleared in the CCR register.
The OR bit is reset by an access to the SCISR register followed by a SCIDR register read operation.
Noise Error
Oversampling techniques are used for data recovery by discriminating between valid incoming data
and noise. Normal data bits are considered valid if
three consecutive samples (8th, 9th, 10th) have
the same bit value, otherwise the NF flag is set. In
the case of start bit detection, the NF flag is set on
the basis of an algorithm combining both valid
edge detection and three samples (8th, 9th, 10th).
Therefore, to prevent the NF flag getting set during
start bit reception, there should be a valid edge detection as well as three valid samples.
When noise is detected in a frame:
– The NF flag is set at the rising edge of the RDRF
bit.
– Data is transferred from the Shift register to the
SCIDR register.
– No interrupt is generated. However this bit rises
at the same time as the RDRF bit which itself
generates an interrupt.
The NF flag is reset by a SCISR register read operation followed by a SCIDR register read operation.
During reception, if a false start bit is detected (e.g.
8th, 9th, 10th samples are 011,101,110), the
frame is discarded and the receiving sequence is
not started for this frame. There is no RDRF bit set
for this frame and the NF flag is set internally (not
accessible to the user). This NF flag is accessible
along with the RDRF bit when a next valid frame is
received.
Note: If the application Start Bit is not long enough
to match the above requirements, then the NF
Flag may get set due to the short Start Bit. In this
case, the NF flag may be ignored by the application software when the first valid byte is received.
See also Section 9.6.4.10.
ST72321M6 ST72321M9
SERIAL COMMUNICATIONS INTERFACE (Cont’d)
Figure 59. SCI Baud Rate and Extended Prescaler Block Diagram
TRANSMITTER
CLOCK
EXTENDED PRESCALER TRANSMITTER RATE CONTROL
SCIETPR
EXTENDED TRANSMITTER PRESCALER REGISTER
SCIERPR
EXTENDED RECEIVER PRESCALER REGISTER
RECEIVER
CLOCK
EXTENDED PRESCALER RECEIVER RATE CONTROL
EXTENDED PRESCALER
fCPU
TRANSMITTER RATE
CONTROL
/16
/PR
SCIBRR
SCP1 SCP0 SCT2 SCT1 SCT0 SCR2 SCR1SCR0
RECEIVER RATE
CONTROL
CONVENTIONAL BAUD RATE GENERATOR
100/175
ST72321M6 ST72321M9
SERIAL COMMUNICATIONS INTERFACE (Cont’d)
Framing Error
A framing error is detected when:
– The stop bit is not recognized on reception at the
expected time, following either a de-synchronization or excessive noise.
– A break is received.
When the framing error is detected:
– the FE bit is set by hardware
– Data is transferred from the Shift register to the
SCIDR register.
– No interrupt is generated. However this bit rises
at the same time as the RDRF bit which itself
generates an interrupt.
The FE bit is reset by a SCISR register read operation followed by a SCIDR register read operation.
9.6.4.4 Conventional Baud Rate Generation
The baud rate for the receiver and transmitter (Rx
and Tx) are set independently and calculated as
follows:
Tx =
fCPU
(16*PR)*TR
Rx =
fCPU
(16*PR)*RR
with:
PR = 1, 3, 4 or 13 (see SCP[1:0] bits)
TR = 1, 2, 4, 8, 16, 32, 64,128
(see SCT[2:0] bits)
RR = 1, 2, 4, 8, 16, 32, 64,128
(see SCR[2:0] bits)
All these bits are in the SCIBRR register.
Example: If fCPU is 8 MHz (normal mode) and if
PR = 13 and TR = RR = 1, the transmit and receive baud rates are 38400 baud.
Note: The baud rate registers MUST NOT be
changed while the transmitter or the receiver is enabled.
9.6.4.5 Extended Baud Rate Generation
The extended prescaler option gives a very fine
tuning on the baud rate, using a 255 value prescaler, whereas the conventional Baud Rate Generator retains industry standard software compatibility.
The extended baud rate generator block diagram
is described in the Figure 59
The output clock rate sent to the transmitter or to
the receiver is the output from the 16 divider divided by a factor ranging from 1 to 255 set in the SCIERPR or the SCIETPR register.
101/175
Note: the extended prescaler is activated by setting the SCIETPR or SCIERPR register to a value
other than zero. The baud rates are calculated as
follows:
fCPU
fCPU
Rx =
Tx =
16*ERPR*(PR*RR)
16*ETPR*(PR*TR)
with:
ETPR = 1,..,255 (see SCIETPR register)
ERPR = 1,.. 255 (see SCIERPR register)
9.6.4.6 Receiver Muting and Wake-up Feature
In multiprocessor configurations it is often desirable that only the intended message recipient
should actively receive the full message contents,
thus reducing redundant SCI service overhead for
all non addressed receivers.
The non addressed devices may be placed in
sleep mode by means of the muting function.
Setting the RWU bit by software puts the SCI in
sleep mode:
All the reception status bits can not be set.
All the receive interrupts are inhibited.
A muted receiver may be awakened by one of the
following two ways:
– by Idle Line detection if the WAKE bit is reset,
– by Address Mark detection if the WAKE bit is set.
Receiver wakes-up by Idle Line detection when
the Receive line has recognized an Idle Frame.
Then the RWU bit is reset by hardware but the
IDLE bit is not set.
Receiver wakes-up by Address Mark detection
when it received a “1” as the most significant bit of
a word, thus indicating that the message is an address. The reception of this particular word wakes
up the receiver, resets the RWU bit and sets the
RDRF bit, which allows the receiver to receive this
word normally and to use it as an address word.
CAUTION: In Mute mode, do not write to the
SCICR2 register. If the SCI is in Mute mode during
the read operation (RWU = 1) and a address mark
wake up event occurs (RWU is reset) before the
write operation, the RWU bit is set again by this
write operation. Consequently the address byte is
lost and the SCI is not woken up from Mute mode.
ST72321M6 ST72321M9
SERIAL COMMUNICATIONS INTERFACE (Cont’d)
9.6.4.7 Parity Control
Parity control (generation of parity bit in transmission and parity checking in reception) can be enabled by setting the PCE bit in the SCICR1 register.
Depending on the frame length defined by the M
bit, the possible SCI frame formats are as listed in
Table 19.
Table 19. Frame Formats
M bit
0
0
1
1
PCE bit
0
1
0
1
SCI frame
| SB | 8 bit data | STB |
| SB | 7-bit data | PB | STB |
| SB | 9-bit data | STB |
| SB | 8-bit data PB | STB |
Legend: SB = Start Bit, STB = Stop Bit,
PB = Parity Bit
Note: In case of wake up by an address mark, the
MSB bit of the data is taken into account and not
the parity bit
Even parity: the parity bit is calculated to obtain
an even number of “1s” inside the frame made of
the 7 or 8 LSB bits (depending on whether M is
equal to 0 or 1) and the parity bit.
Example: data = 00110101; 4 bits set => 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
102/175
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).
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.
Figure 60. Bit Sampling in Reception Mode
RDI LINE
sampled values
Sample
clock
1
2
3
4
5
6
7
8
9
10
11
12
13
6/16
7/16
7/16
One bit time
103/175
14
15
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.
Interrupt Event
Enable Exit
Event
Control from
Flag
Bit
Wait
Transmit Data Register
TDRE
Empty
Transmission ComTC
plete
Received Data Ready
RDRF
to be Read
Overrun Error DetectOR
ed
Idle Line Detected
IDLE
Parity Error
PE
104/175
Exit
from
Halt
TIE
Yes
No
TCIE
Yes
No
Yes
No
Yes
No
Yes
Yes
No
No
RIE
ILIE
PIE
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.
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
105/175
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 4 = M Word length.
This bit determines the word length. It is set or
cleared by software.
0: 1 Start bit, 8 Data bits, 1 Stop bit
1: 1 Start bit, 9 Data bits, 1 Stop bit
Note: The M bit must not be modified during a data
transfer (both transmission and reception).
106/175
Bit 2 = PCE Parity control enable.
This bit selects the hardware parity control (generation and detection). When the parity control is enabled, the computed parity is inserted at the MSB
position (9th bit if M = 1; 8th bit if M = 0) and parity
is checked on the received data. This bit is set and
cleared by software. Once it is set, PCE is active
after the current byte (in reception and in transmission).
0: Parity control disabled
1: Parity control enabled
Bit 1 = PS Parity selection.
This bit selects the odd or even parity when the
parity generation/detection is enabled (PCE bit
set). It is set and cleared by software. The parity is
selected after the current byte.
0: Even parity
1: Odd parity
Bit 0 = PIE Parity interrupt enable.
This bit enables the interrupt capability of the hardware parity control when a parity error is detected
(PE bit set). It is set and cleared by software.
0: Parity error interrupt disabled
1: Parity error interrupt enabled.
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.
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
107/175
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
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)
7
0
SCP1
SCP0
SCT2
SCT1
SCT0
SCR2
SCR1 SCR0
Bits 7:6 = SCP[1:0] First SCI Prescaler
These 2 prescaling bits allow several standard
clock division ranges:
PR Prescaling factor
SCP1
SCP0
1
0
0
3
0
1
4
1
0
13
1
1
108/175
Bits 5:3 = SCT[2:0] SCI Transmitter rate divisor
These 3 bits, in conjunction with the SCP1 & SCP0
bits define the total division applied to the bus
clock to yield the transmit rate clock in conventional Baud Rate Generator mode.
TR dividing factor
SCT2
SCT1
SCT0
1
0
0
0
2
0
0
1
4
0
1
0
8
0
1
1
16
1
0
0
32
1
0
1
64
1
1
0
128
1
1
1
Bits 2:0 = SCR[2:0] SCI Receiver rate divisor.
These 3 bits, in conjunction with the SCP[1:0] bits
define the total division applied to the bus clock to
yield the receive rate clock in conventional Baud
Rate Generator mode.
RR Dividing factor
SCR2
SCR1
SCR0
1
0
0
0
2
0
0
1
4
0
1
0
8
0
1
1
16
1
0
0
32
1
0
1
64
1
1
0
128
1
1
1
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
0
EXTENDED TRANSMIT PRESCALER DIVISION
REGISTER (SCIETPR)
Read/Write
Reset Value:0000 0000 (00h)
Allows setting of the External Prescaler rate division factor for the transmit circuit.
7
ERPR ERPR ERPR ERPR ERPR ERPR ERPR ERPR
7
6
5
4
3
2
1
0
ETPR
7
Bits 7:0 = ERPR[7:0] 8-bit Extended Receive
Prescaler Register.
The extended Baud Rate Generator is activated
when a value different from 00h is stored in this
register. Therefore the clock frequency issued
from the 16 divider (see Figure 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.
0
ETPR
6
ETPR
5
ETPR
4
ETPR
3
ETPR
2
ETPR ETPR
1
0
Bits 7:0 = ETPR[7:0] 8-bit Extended Transmit
Prescaler Register.
The extended Baud Rate Generator is activated
when a value different from 00h is stored in this
register. Therefore the clock frequency issued
from the 16 divider (see Figure 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
Conditions
Symbol
fTx
fRx
Parameter
fCPU
Accuracy vs
Standard
Prescaler
~0.16%
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
Communication frequency 8 MHz
~0.79%
109/175
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
110/175
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
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.
Figure 61. I2C BUS Protocol
SDA
ACK
MSB
SCL
1
START
CONDITION
111/175
2
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.
Figure 62. I2C Interface Block Diagram
DATA REGISTER (DR)
SDA or SDAI
DATA CONTROL
DATA SHIFT REGISTER
COMPARATOR
OWN ADDRESS REGISTER 1 (OAR1)
OWN ADDRESS REGISTER 2 (OAR2)
SCL or SCLI
CLOCK CONTROL
CLOCK CONTROL REGISTER (CCR)
CONTROL REGISTER (CR)
STATUS REGISTER 1 (SR1)
CONTROL LOGIC
STATUS REGISTER 2 (SR2)
INTERRUPT
112/175
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.
113/175
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.
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).
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).
114/175
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).
Next the master must enter Receiver or Transmitter mode.
Note: In 10-bit addressing mode, to switch the
master to Receiver mode, software must generate
a repeated Start condition and resend the header
sequence with the least significant bit set
(11110xx1).
Master Receiver
Following the address transmission and after SR1
and CR registers have been accessed, the master
receives bytes from the SDA line into the DR register via the internal shift register. After each byte
the interface generates in sequence:
– Acknowledge pulse if the ACK bit is set
– EVF and BTF bits are set by hardware with an interrupt if the ITE bit is set.
Then the interface waits for a read of the SR1 register followed by a read of the DR register, holding
the SCL line low (see Figure 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.
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
115/175
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.
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
7-bit Master receiver:
S
Address
A
EV5
Data1
A
EV6
Data2
A
EV7
EV7
DataN
.....
NA
P
EV7
7-bit Master transmitter:
S
Address
A
EV5
Data1
A
EV6 EV8
Data2
A
EV8
DataN
.....
EV8
A
P
EV8
10-bit Slave receiver:
S Header
A
Address
A
Data1
A
EV1
.....
EV2
DataN
A
P
EV2
EV4
10-bit Slave transmitter:
Sr Header A
Data1
A
EV1 EV3
EV3
.... DataN
.
A
P
EV3-1
EV4
10-bit Master transmitter
S
Header
EV5
A
Address
EV9
A
Data1
A
EV6 EV8
EV8
DataN
.....
A
P
EV8
10-bit Master receiver:
Sr
Header
EV5
A
Data1
EV6
A
EV7
.....
DataN
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.
116/175
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
ITE
INTERRUPT
EVF
*
* EVF can also be set by EV6 or an error from the SR2 register.
Interrupt Event
10-bit Address Sent Event (Master mode)
End of Byte Transfer Event
Address Matched Event (Slave mode)
Start Bit Generation Event (Master mode)
Acknowledge Failure Event
Stop Detection Event (Slave mode)
Arbitration Lost Event (Multimaster configuration)
Bus Error Event
Note: The I2C interrupt events are connected to
the same interrupt vector (see Interrupts chapter).
They generate an interrupt if the corresponding
Enable Control Bit is set and the I-bit in the CC register is reset (RIM instruction).
117/175
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
Bit 7:6 = Reserved. Forced to 0 by hardware.
Bit 5 = PE Peripheral enable.
This bit is set and cleared by software.
0: Peripheral disabled
1: Master/Slave capability
Notes:
– When PE=0, all the bits of the CR register and
the SR register except the Stop bit are reset. All
outputs are released while PE=0
– When PE=1, the corresponding I/O pins are selected by hardware as alternate functions.
– To enable the I2C interface, write the CR register
TWICE with PE=1 as the first write only activates
the interface (only PE is set).
Bit 4 = ENGC Enable General Call.
This bit is set and cleared by software. It is also
cleared by hardware when the interface is disabled (PE=0). The 00h General Call address is acknowledged (01h ignored).
0: General Call disabled
1: General Call enabled
Note: In accordance with the I2C standard, when
GCAL addressing is enabled, an I2C slave can
only receive data. It will not transmit data to the
master.
Bit 3 = START Generation of a Start condition.
This bit is set and cleared by software. It is also
cleared by hardware when the interface is disabled (PE=0) or when the Start condition is sent
(with interrupt generation if ITE=1).
– In master mode:
0: No start generation
1: Repeated start generation
118/175
Bit 1 = STOP Generation of a Stop condition.
This bit is set and cleared by software. It is also
cleared by hardware in master mode. Note: This
bit is not cleared when the interface is disabled
(PE=0).
– In master mode:
0: No stop generation
1: Stop generation after the current byte transfer
or after the current Start condition is sent. The
STOP bit is cleared by hardware when the Stop
condition is sent.
– In slave mode:
0: No stop generation
1: Release the SCL and SDA lines after the current byte transfer (BTF=1). In this mode the
STOP bit has to be cleared by software.
Bit 0 = ITE Interrupt enable.
This bit is set and cleared by software and cleared
by hardware when the interface is disabled
(PE=0).
0: Interrupts disabled
1: Interrupts enabled
Refer to Figure 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 6 = ADD10 10-bit addressing in Master mode.
This bit is set by hardware when the master has
sent the first byte in 10-bit address mode. It is
cleared by software reading SR2 register followed
by a write in the DR register of the second address
byte. It is also cleared by hardware when the peripheral is disabled (PE=0).
0: No ADD10 event occurred.
1: Master has sent first address byte (header)
Bit 5 = TRA Transmitter/Receiver.
When BTF is set, TRA=1 if a data byte has been
transmitted. It is cleared automatically when BTF
is cleared. It is also cleared by hardware after detection of Stop condition (STOPF=1), loss of bus
arbitration (ARLO=1) or when the interface is disabled (PE=0).
0: Data byte received (if BTF=1)
119/175
Bit 4 = BUSY Bus busy.
This bit is set by hardware on detection of a Start
condition and cleared by hardware on detection of
a Stop condition. It indicates a communication in
progress on the bus. The BUSY flag of the I2CSR1
register is cleared if a Bus Error occurs.
0: No communication on the bus
1: Communication ongoing on the bus
Note:
– The BUSY flag is NOT updated when the interface is disabled (PE=0). This can have consequences when operating in Multimaster mode;
i.e. a second active I2C master commencing a
transfer with an unset BUSY bit can cause a conflict resulting in lost data. A software workaround
consists of checking that the I2C is not busy before enabling the I2C Multimaster cell.
Bit 3 = BTF Byte transfer finished.
This bit is set by hardware as soon as a byte is correctly received or transmitted with interrupt generation if ITE=1. It is cleared by software reading
SR1 register followed by a read or write of DR register. It is also cleared by hardware when the interface is disabled (PE=0).
– Following a byte transmission, this bit is set after
reception of the acknowledge clock pulse. In
case an address byte is sent, this bit is set only
after the EV6 event (See Figure 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
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
I2C STATUS REGISTER 2 (SR2)
Read Only
Reset Value: 0000 0000 (00h)
7
0
0
0
0
AF
STOPF ARLO BERR GCAL
Bit 7:5 = Reserved. Forced to 0 by hardware.
Bit 4 = AF Acknowledge failure.
This bit is set by hardware when no acknowledge
is returned. An interrupt is generated if ITE=1. It is
cleared by software reading SR2 register or by
hardware when the interface is disabled (PE=0).
The SCL line is not held low while AF=1 but by other flags (SB or BTF) that are set at the same time.
0: No acknowledge failure
1: Acknowledge failure
Note:
– When an AF event occurs, the SCL line is not
held low; however, the SDA line can remain low
if the last bits transmitted are all 0. It is then necessary to release both lines by software.
Bit 3 = STOPF Stop detection (Slave mode).
This bit is set by hardware when a Stop condition
is detected on the bus after an acknowledge (if
ACK=1). An interrupt is generated if ITE=1. It is
cleared by software reading SR2 register or by
hardware when the interface is disabled (PE=0).
120/175
The SCL line is not held low while STOPF=1.
0: No Stop condition detected
1: Stop condition detected
Bit 2 = ARLO Arbitration lost.
This bit is set by hardware when the interface loses the arbitration of the bus to another master. An
interrupt is generated if ITE=1. It is cleared by software reading SR2 register or by hardware when
the interface is disabled (PE=0).
After an ARLO event the interface switches back
automatically to Slave mode (M/SL=0).
The SCL line is not held low while ARLO=1.
0: No arbitration lost detected
1: Arbitration lost detected
Note:
– In a Multimaster environment, when the interface
is configured in Master Receive mode it does not
perform arbitration during the reception of the
Acknowledge Bit. Mishandling of the ARLO bit
from the I2CSR2 register may occur when a second master simultaneously requests the same
data from the same slave and the I2C master
does not acknowledge the data. The ARLO bit is
then left at 0 instead of being set.
Bit 1 = BERR Bus error.
This bit is set by hardware when the interface detects a misplaced Start or Stop condition. An interrupt is generated if ITE=1. It is cleared by software
reading SR2 register or by hardware when the interface is disabled (PE=0).
The SCL line is not held low while BERR=1.
0: No misplaced Start or Stop condition
1: Misplaced Start or Stop condition
Note:
– If a Bus Error occurs, a Stop or a repeated Start
condition should be generated by the Master to
re-synchronize communication, get the transmission acknowledged and the bus released for further communication
Bit 0 = GCAL General Call (Slave mode).
This bit is set by hardware when a general call address is detected on the bus while ENGC=1. It is
cleared by hardware detecting a Stop condition
(STOPF=1) or when the interface is disabled
(PE=0).
0: No general call address detected on bus
1: general call address detected on bus
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.
121/175
0
D6
D5
D4
D3
D2
D1
D0
Bit 7:0 = D[7:0] 8-bit Data Register.
These bits contain the byte to be received or transmitted on the bus.
– Transmitter mode: Byte transmission start automatically when the software writes in the DR register.
– Receiver mode: the first data byte is received automatically in the DR register using the least significant bit of the address.
Then, the following data bytes are received one
by one after reading the DR register.
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
FR0
0
1
Bit 0 = ADD0 Address direction bit.
This bit is don’t care, the interface acknowledges
either 0 or 1. It is not cleared when the interface is
disabled (PE=0).
Note: Address 01h is always ignored.
Bit 5:3 = Reserved
10-bit Addressing Mode
Bit 7:0 = ADD[7:0] Interface address.
These are the least significant bits of the I2C bus
address of the interface. They are not cleared
when the interface is disabled (PE=0).
Bit 2:1 = ADD[9:8] Interface address.
These are the most significant bits of the I2C bus
address of the interface (10-bit mode only). They
are not cleared when the interface is disabled
(PE=0).
Bit 0 = Reserved.
122/175
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
0
LSB
0
123/175
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.
Figure 65. ADC Block Diagram
fCPU
DIV 4
0
DIV 2
fADC
1
EOC SPEED ADON
0
CH3
CH2
CH1
CH0
ADCCSR
4
AIN0
AIN1
ANALOG TO DIGITAL
ANALOG
MUX
CONVERTER
AINx
ADCDRH
D9
D8
ADCDRL
124/175
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.
125/175
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.
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
EOC SPEED ADON
Bit 3:0 = CH[3:0] Channel Selection
These bits are set and cleared by software. They
select the analog input to convert.
0
0
CH3
CH2
CH1
CH0
Bit 7 = EOC End of Conversion
This bit is set by hardware. It is cleared by hardware when software reads the ADCDRH register
or writes to any bit of the ADCCSR register.
0: Conversion is not complete
1: Conversion complete
Bit 6 = SPEED ADC clock selection
This bit is set and cleared by software.
0: fADC = fCPU/4
1: fADC = fCPU/2
Bit 5 = ADON A/D Converter on
This bit is set and cleared by software.
0: Disable ADC and stop conversion
1: Enable ADC and start conversion
Bit 4 = Reserved. Must be kept cleared.
Channel Pin*
CH3
CH2
CH1
CH0
AIN0
AIN1
AIN2
AIN3
AIN4
AIN5
AIN6
AIN7
AIN8
AIN9
AIN10
AIN11
AIN12
AIN13
AIN14
AIN15
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
*The number of channels is device dependent. Refer to
the device pinout description.
DATA REGISTER (ADCDRH)
Read Only
Reset Value: 0000 0000 (00h)
7
D9
0
D8
D7
D6
D5
D4
D3
D2
Bit 7:0 = D[9:2] MSB of Converted Analog Value
DATA REGISTER (ADCDRL)
Read Only
Reset Value: 0000 0000 (00h)
7
0
0
0
0
0
0
0
D1
D0
Bit 7:2 = Reserved. Forced by hardware to 0.
Bit 1:0 = D[1:0] LSB of Converted Analog Value
126/175
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
127/175
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
byte,#5
The CPU Instruction set is designed to minimize
the number of bytes required per instruction: To do
so, most of the addressing modes may be subdivided in two 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.
Table 24. CPU Addressing Mode Overview
Mode
Syntax
Destination
Pointer
Address
(Hex.)
Pointer Size
(Hex.)
Length
(Bytes)
Inherent
nop
+0
Immediate
ld A,#$55
+1
Short
Direct
ld A,$10
00..FF
+1
Long
Direct
ld A,$1000
0000..FFFF
+2
No Offset
Direct
Indexed
ld A,(X)
00..FF
+0
Short
Direct
Indexed
ld A,($10,X)
00..1FE
+1
Long
Direct
Indexed
ld A,($1000,X)
0000..FFFF
+2
Short
Indirect
ld A,[$10]
00..FF
00..FF
byte
+2
Long
Indirect
ld A,[$10.w]
0000..FFFF
00..FF
word
+2
Short
Indirect
Indexed
ld A,([$10],X)
00..1FE
00..FF
byte
+2
Long
Indirect
Indexed
ld A,([$10.w],X)
0000..FFFF
00..FF
word
+2
Relative
Direct
jrne loop
PC+/-127
Relative
Indirect
jrne [$10]
PC+/-127
Bit
Direct
bset $10,#7
00..FF
Bit
Indirect
bset [$10],#7
00..FF
Bit
Direct
Relative
btjt $10,#7,skip
00..FF
Bit
Indirect
Relative
btjt [$10],#7,skip
00..FF
128/175
+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
INC/DEC
Increment/Decrement
TNZ
Test Negative or Zero
CPL, NEG
1 or 2 Complement
MUL
Byte Multiplication
SLL, SRL, SRA, RLC,
RRC
Shift and Rotate Operations
SWAP
Swap Nibbles
10.1.2 Immediate
Immediate instructions have 2 bytes, the first byte
contains the opcode, the second byte contains the
operand value.
Immediate Instruction
Function
LD
Load
CP
Compare
BCP
Bit Compare
AND, OR, XOR
Logical Operations
ADC, ADD, SUB, SBC
Arithmetic Operations
129/175
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.
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.
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
LD
Function
Load
CP
Compare
AND, OR, XOR
Logical Operations
ADC, ADD, SUB, SBC
Arithmetic Additions/Substractions operations
BCP
Bit Compare
Short Instructions Only
Function
CLR
Clear
INC, DEC
Increment/Decrement
TNZ
Test Negative or Zero
CPL, NEG
1 or 2 Complement
BSET, BRES
Bit Operations
BTJT, BTJF
Bit Test and Jump Operations
SLL, SRL, SRA, RLC,
RRC
Shift and Rotate Operations
SWAP
Swap Nibbles
CALL, JP
Call or Jump subroutine
130/175
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.
Available Relative
Direct/Indirect
Instructions
Function
JRxx
Conditional Jump
CALLR
Call Relative
The relative addressing mode consists of two submodes:
Relative (Direct)
The offset is following the opcode.
Relative (Indirect)
The offset is defined in memory, which address
follows the opcode.
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
SWAP
SLA
Unconditional Jump or Call
JRA
JRT
JRF
JP
CALL
CALLR
NOP
Conditional Branch
JRxx
Interruption management
TRAP
WFI
HALT
IRET
Condition Code Flag modification
SIM
RIM
SCF
RCF
Using a 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
131/175
RET
These prebytes enable instruction in Y as well as
indirect addressing modes to be implemented.
They precede the opcode of the instruction in X or
the instruction using direct addressing mode. The
prebytes are:
PDY 90
Replace an X based instruction
using immediate, direct, indexed, or inherent addressing mode by a Y one.
PIX 92
Replace an instruction using direct, direct bit, or direct relative addressing mode
to an instruction using the corresponding indirect
addressing mode.
It also changes an instruction using X indexed addressing mode to an instruction using indirect X indexed addressing mode.
PIY 91
Replace an instruction using X indirect indexed addressing mode by a Y one.
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
C
BTJT
Jump if bit is true (1)
btjt Byte, #3, Jmp1
M
C
CALL
Call subroutine
CALLR
Call subroutine relative
CLR
Clear
CP
Arithmetic Compare
tst(Reg - M)
reg
CPL
One Complement
A = FFH-A
DEC
Decrement
dec Y
HALT
Halt
IRET
Interrupt routine return
Pop CC, A, X, PC
INC
Increment
inc X
JP
Absolute Jump
jp [TBL.w]
JRA
Jump relative always
JRT
Jump relative
JRF
Never jump
jrf *
JRIH
Jump if ext. INT pin = 1
(ext. INT pin high)
JRIL
Jump if ext. INT pin = 0
(ext. INT pin low)
JRH
Jump if H = 1
H=1?
JRNH
Jump if H = 0
H=0?
JRM
Jump if I1:0 = 11
I1:0 = 11 ?
JRNM
Jump if I1:0 <> 11
I1:0 <> 11 ?
JRMI
Jump if N = 1 (minus)
N=1?
JRPL
Jump if N = 0 (plus)
N=0?
reg, M
1
N
Z
C
reg, M
N
Z
1
reg, M
N
Z
N
Z
N
Z
M
1
JREQ
Jump if Z = 1 (equal)
Z=1?
JRNE
Jump if Z = 0 (not equal)
Z=0?
JRC
Jump if C = 1
C=1?
JRNC
Jump if C = 0
C=0?
JRULT
Jump if C = 1
Unsigned <
JRUGE
Jump if C = 0
Jmp if unsigned >=
JRUGT
Jump if (C + Z = 0)
Unsigned >
132/175
0
I1
reg, M
0
H
I0
C
ST72321M6 ST72321M9
INSTRUCTION SET OVERVIEW (Cont’d)
Mnemo
Description
Dst
Src
JRULE
Jump if (C + Z = 1)
Unsigned <=
LD
Load
dst <= src
reg, M
M, reg
MUL
Multiply
X,A = X * A
A, X, Y
X, Y, A
NEG
Negate (2's compl)
neg $10
reg, M
NOP
No Operation
OR
OR operation
A=A+M
A
M
POP
Pop from the Stack
pop reg
reg
M
pop CC
CC
M
PUSH
Push onto the Stack
push Y
M
reg, CC
RCF
Reset carry flag
C=0
RET
Subroutine Return
RIM
Enable Interrupts
I1:0 = 10 (level 0)
RLC
Rotate left true C
C <= A <= C
reg, M
N
Z
C
RRC
Rotate right true C
C => A => C
reg, M
N
Z
C
RSP
Reset Stack Pointer
S = Max allowed
SBC
Substract with Carry
A=A-M-C
N
Z
C
SCF
Set carry flag
C=1
SIM
Disable Interrupts
I1:0 = 11 (level 3)
SLA
Shift left Arithmetic
C <= A <= 0
reg, M
N
Z
C
SLL
Shift left Logic
C <= A <= 0
reg, M
N
Z
C
SRL
Shift right Logic
0 => A => C
reg, M
0
Z
C
SRA
Shift right Arithmetic
A7 => A => C
reg, M
N
Z
C
SUB
Substraction
A=A-M
A
N
Z
C
SWAP
SWAP nibbles
A7-A4 <=> A3-A0
reg, M
N
Z
TNZ
Test for Neg & Zero
tnz lbl1
N
Z
TRAP
S/W trap
S/W interrupt
WFI
Wait for Interrupt
XOR
Exclusive OR
N
Z
133/175
Function/Example
A = A XOR M
I1
H
I0
N
Z
N
Z
0
I1
H
C
0
I0
N
Z
N
Z
N
Z
C
C
0
1
A
0
M
1
1
A
1
M
M
1
1
1
0
ST72321M6 ST72321M9
11 ELECTRICAL CHARACTERISTICS
11.1 PARAMETER CONDITIONS
Unless otherwise specified, all voltages are referred to VSS.
11.1.1 Minimum and Maximum values
Unless otherwise specified the minimum and maximum values are guaranteed in the worst conditions of ambient temperature, supply voltage and
frequencies by tests in production on 100% of the
devices with an ambient temperature at TA=25 °C
and TA=TAmax (given by the selected temperature
range).
Data based on characterization results, design
simulation and/or technology characteristics are
indicated in the table footnotes and are not tested
in production. Based on characterization, the minimum and maximum values refer to sample tests
and represent the mean value plus or minus three
times the standard deviation (mean±3Σ).
11.1.2 Typical values
Unless otherwise specified, typical data are based
on TA= 25 °C, VDD= 5 V.They are given only as
design guidelines and are not tested.
11.1.3 Typical curves
Unless otherwise specified, all typical curves are
given only as design guidelines and are not tested.
11.1.4 Loading capacitor
The loading conditions used for pin parameter
measurement are shown in Figure 66.
Figure 66. Pin loading conditions
ST7 PIN
CL
11.1.5 Pin input voltage
The input voltage measurement on a pin of the device is described in Figure 67.
134/175
Figure 67. Pin input voltage
ST7 PIN
VIN
ST72321M6 ST72321M9
11.2 ABSOLUTE MAXIMUM RATINGS
Stresses above those listed as “absolute maximum ratings” may cause permanent damage to
the device. This is a stress rating only and functional operation of the device under these condi11.2.1 Voltage Characteristics
Symbol
tions is not implied. Exposure to maximum rating
conditions for extended periods may affect device
reliability.
Ratings
Maximum value
VDD - VSS
Supply voltage
6.5
VPP - VSS
Programming Voltage
13
VIN
1) & 2)
Input Voltage on true open drain pin
VSS-0.3 to 6.5
|VSSA - VSSx|
V
VSS-0.3 to VDD+0.3
Input voltage on any other pin
|ΔVDDx| and |ΔVSSx|
Unit
Variations between different digital power pins
50
Variations between digital and analog ground pins
50
VESD(HBM)
Electro-static discharge voltage (Human Body Model)
VESD(MM)
Electro-static discharge voltage (Machine Model)
mV
see section 11.7.3 on page 150
11.2.2 Current Characteristics
Symbol
Ratings
Maximum value
IVDD
Total current into VDD power lines (source)
3)
150
IVSS
Total current out of VSS ground lines (sink) 3)
150
IIO
IINJ(PIN) 2) & 4)
ΣIINJ(PIN) 2)
Output current sunk by any standard I/O and control pin
25
Output current sunk by any high sink I/O pin
50
Output current source by any I/Os and control pin
- 25
Injected current on VPP pin
+5
Injected current on RESET pin
+5
Injected current on OSC1 and OSC2 pins
+5
Injected current on any other pin 5) & 6)
±5
Total injected current (sum of all I/O and control pins) 5)
± 25
Unit
mA
mA
mA
Notes:
1. Directly connecting the RESET and I/O pins to VDD or VSS could damage the device if an unintentional internal reset
is generated or an unexpected change of the I/O configuration occurs (for example, due to a corrupted program counter).
To guarantee safe operation, this connection has to be done through a pull-up or pull-down resistor (typical: 4.7 kΩ for
RESET, 10 kΩ for I/Os). For the same reason, unused I/O pins must not be directly tied to VDD or VSS.
2. IINJ(PIN) must never be exceeded. This is implicitly insured if VIN maximum is respected. If VIN maximum cannot be
respected, the injection current must be limited externally to the IINJ(PIN) value. A positive injection is induced by VIN>VDD
while a negative injection is induced by VIN<VSS. For true open-drain pads, there is no positive injection current, and the
corresponding VIN maximum must always be respected
3. All power (VDD) and ground (VSS) lines must always be connected to the external supply.
4. Negative injection disturbs the analog performance of the device. See note in “ADC Accuracy” on page 165.
For best reliability, it is recommended to avoid negative injection of more than 1.6 mA.
5. When several inputs are submitted to a current injection, the maximum ΣIINJ(PIN) is the absolute sum of the positive
and negative injected currents (instantaneous values). These results are based on characterisation with ΣIINJ(PIN) maximum current injection on four I/O port pins of the device.
6. True open drain I/O port pins do not accept positive injection.
135/175
ST72321M6 ST72321M9
11.2.3 Thermal Characteristics
Symbol
TSTG
TJ
Ratings
Storage temperature range
Value
Unit
-65 to +150
°C
Maximum junction temperature (see Section 12.3 THERMAL CHARACTERISTICS)
11.3 OPERATING CONDITIONS
11.3.1 General Operating Conditions
Symbol
Parameter
Conditions
fCPU
Internal clock frequency
VDD
Standard voltage range (except Flash
Write/Erase)
Operating Voltage for Flash Write/Erase
TA
Ambient temperature range
Min
Max
Unit
0
8
MHz
3.8
5.5
4.5
5.5
1 Suffix Version
0
70
5 Suffix Version
-10
85
6 or A Suffix Versions
-40
85
7 or B Suffix Versions
-40
105
3 or C Suffix Version
-40
125
VPP = 11.4 to 12.6 V
V
°C
Figure 68. fCPU Max Versus VDD
fCPU [MHz]
FUNCTIONALITY
GUARANTEED
IN THIS AREA
(UNLESS
OTHERWISE
SPECIFIED
IN THE TABLES
OF PARAMETRIC
DATA)
8
FUNCTIONALITY
NOT GUARANTEED
IN THIS AREA
6
4
2
1
0
3.5
3.8 4.0
4.5
5.5
SUPPLY VOLTAGE [V]
Note: Some temperature ranges are only available with a specific package and memory size. Refer to Ordering Information.
136/175
ST72321M6 ST72321M9
OPERATING CONDITIONS (Cont’d)
11.3.2 Operating Conditions with Low Voltage Detector (LVD)
Subject to general operating conditions for VDD, fCPU, and TA.
Symbol
VIT+(LVD)
Reset release threshold
(VDD rise)
VIT-(LVD)
Reset generation threshold
(VDD fall)
Vhys(LVD)
Conditions
Min
Typ
Max
VD level = High in option byte
4.01)
4.2
4.5
VD level = Med. in option byte2) 3.551)
VD level = Low in option byte2) 2.951)
3.75
3.15
4.01)
3.351)
VD level = High in option byte
4.0
4.251)
3.55
3.0
3.751))
3.15 1)
Parameter
3.8
VD level = Med. in option byte2) 3.351)
VD level = Low in option byte2) 2.81)
VtPOR
LVD voltage threshold hysteresis VIT+(LVD)-VIT-(LVD)
VDD rise time 3)2)
LVD enabled
tg(VDD)
VDD glitches filtered (not detected) by LVD 3)
200
Unit
V
mV
6 μs/V
100 ms/V
40
ns
Notes:
1. Data based on characterization results, not tested in production.
2. If the medium or low thresholds are selected, the detection may occur outside the specified operating voltage range.
Below 3.8 V, device operation is not guaranteed.
3. Data based on characterization results, not tested in production.
3. When VtPOR is faster than 100 μs/V, the Reset signal is released after a delay of max. 42 µs after VDD crosses the
VIT+(LVD) threshold.
11.3.3 Auxiliary Voltage Detector (AVD) Thresholds
Subject to general operating conditions for VDD, fCPU, and TA.
Symbol
Parameter
Conditions
Min
Typ
Max
4.6
4.91)
VD level = Med. in option byte
VD level = Low in option byte
3.95 1)
3.4 1)
4.15
3.6
4.41)
3.81)
VD level = High in option byte
4.21)
4.4
4.65 1)
VD level = Med. in option byte
VD level = Low in option byte
3.751)
3.21)
4.0
3.4
4.2 1)
3.61)
VD level = High in option byte
4.4
1)
Unit
VIT+(AVD)
1 ⇒0 AVDF flag toggle threshold
(VDD rise)
VIT-(AVD)
0 ⇒1 AVDF flag toggle threshold
(VDD fall)
Vhys(AVD)
AVD voltage threshold hysteresis
VIT+(AVD)-VIT-(AVD)
200
mV
ΔVIT-
Voltage drop between AVD flag set
and LVD reset activated
VIT-(AVD)-VIT-(LVD)
450
mV
V
1. Data based on characterization results, not tested in production.
11.3.4 External Voltage Detector (EVD) Thresholds
Subject to general operating conditions for VDD, fCPU, and TA.
Symbol
Parameter
Conditions
Min
Typ
Max
VIT+(EVD)
1⇒0 AVDF flag toggle threshold
(VDD rise)1)
1.15
1.26
1.35
VIT-(EVD)
0 ⇒1 AVDF flag toggle threshold
(VDD fall)1)
1.1
1.2
1.3
Vhys(EVD)
EVD voltage threshold hysteresis
V
VIT+(EVD)-VIT-(EVD)
1. Data based on characterization results, not tested in production.
137/175
Unit
200
mV
ST72321M6 ST72321M9
11.4 SUPPLY CURRENT CHARACTERISTICS
The following current consumption specified for the ST7 functional operating modes over temperature
range does not take into account the clock source current consumption. To get the total device consumption, the two current values must be added (except for Halt mode for which the clock is stopped).
11.4.1 CURRENT CONSUMPTION
Symbol
Parameter
Conditions
fOSC=2 MHz, fCPU=1 MHz
fOSC=4 MHz, fCPU=2 MHz
fOSC=8 MHz, fCPU=4 MHz
fOSC=16 MHz, fCPU=8 MHz
Supply current in RUN mode 2)
Supply current in Slow mode
fOSC=2 MHz, fCPU=62.5 kHz
fOSC=4 MHz, fCPU=125 kHz
fOSC=8 MHz, fCPU=250 kHz
fOSC=16 MHz, fCPU=500 kHz
2)
fOSC=2 MHz, fCPU=1 MHz
fOSC=4 MHz, fCPU=2 MHz
fOSC=8 MHz, fCPU=4 MHz
fOSC=16 MHz, fCPU=8 MHz
IDD
Supply current in Wait mode 2)
Supply current in Slow wait mode
2)
Supply current in Halt mode 3)
IDD
Supply current in Active-halt mode
fOSC=2 MHz, fCPU=62.5 kHz
fOSC=4 MHz, fCPU=125 kHz
fOSC=8 MHz, fCPU=250 kHz
fOSC=16 MHz, fCPU=500 kHz
-40 °C ≤TA≤+85 °C
4)
fOSC=2 MHz
fOSC=4 MHz
fOSC=8 MHz
fOSC =16 MHz
Typ
Max 1)
Unit
1.3
2.0
3.6
7.1
3.0
5.0
8.0
15.0
mA
600
700
800
1100
2700
3000
3600
4000
μA
1.0
1.5
2.5
4.5
3.0
4.0
5.0
7.0
mA
580
650
770
1050
1200
1300
1800
2000
μA
<1
10
μA
80
160
325
650
No max.
guaranteed
μA
Notes:
1. Data based on characterization results, tested in production at VDD max. and fCPU max.
2. Measurements are done in the following conditions:
- Program executed from RAM, CPU running with RAM access. The increase in consumption when executing from Flash
is 50%.
- All I/O pins in input mode with a static value at VDD or VSS (no load)
- All peripherals in reset state.
- LVD disabled.
- Clock input (OSC1) driven by external square wave.
- In Slow and Slow wait mode, fCPU is based on fOSC divided by 32.
To obtain the total current consumption of the device, add the clock source (Section 11.4.2) and the peripheral power
consumption (Section 11.4.3).
3. All I/O pins in push-pull 0 mode (when applicable) with a static value at VDD or VSS (no load), LVD disabled. Data
based on characterization results, tested in production at VDD max. and fCPU max.
4. Data based on characterisation results, not tested in production. All I/O pins in push-pull 0 mode (when applicable) with
a static value at VDD or VSS (no load); clock input (OSC1) driven by external square wave, LVD disabled. To obtain the
total current consumption of the device, add the clock source consumption (Section 11.4.2).
138/175
ST72321M6 ST72321M9
SUPPLY CURRENT CHARACTERISTICS (Cont’d)
11.4.1.1 Power Consumption vs fCPU
Figure 69. Typical IDD in RUN mode
Figure 71. Typical IDD in Wait mode
8
7
5
4
Idd (mA)
6
Idd (mA)
8MHz
4MHz
2MHz
1MHz
6
8MHz
4MHz
2MHz
1MHz
9
5
4
3
2
3
2
1
1
0
0
3.2
3.6
4
4.4
4.8
5.2
3.2
5.5
3.6
4
5.5
500kHz
1.20
500kHz
250kHz
1.00
125kHz
62.5kHz
0.80
250kHz
125kHz
62.5kHz
)
(
0.80
Idd (mA)
5.2
Figure 72. Typ. IDD in Slow-wait mode
Figure 70. Typical IDD in Slow mode
1.00
4.8
Vdd (V)
Vdd (V)
1.20
4.4
0.60
0.60
0.40
0.40
0.20
0.20
0.00
3.2
0.00
3.2
3.6
4
4.4
Vdd (V)
139/175
4.8
5.2
5.5
3.6
4
4.4
Vdd (V)
4.8
5.2
5.5
ST72321M6 ST72321M9
SUPPLY CURRENT CHARACTERISTICS (Cont’d)
11.4.2 Supply and Clock Managers
The previous current consumption specified for the ST7 functional operating modes over temperature
range does not take into account the clock source current consumption. To get the total device consumption, the two current values must be added (except for Halt mode).
Symbol
Parameter
Conditions
IDD(RCINT) Supply current of internal RC oscillator
Typ
Max
Unit
625
see section
11.5.3 on page
143
IDD(RES)
Supply current of resonator oscillator 1) & 2)
IDD(PLL)
PLL supply current
VDD= 5 V
360
IDD(LVD)
LVD supply current
VDD= 5 V
150
μA
300
Notes:
1.. Data based on characterization results done with the external components specified in Section 11.5.3, not tested in
production.
2. As the oscillator is based on a current source, the consumption does not depend on the voltage.
140/175
ST72321M6 ST72321M9
SUPPLY CURRENT CHARACTERISTICS (Cont’d)
11.4.3 On-Chip Peripherals
Measured on LQFP64 generic board TA = 25 °C fCPU=4 MHz.
Symbol
Typ
Unit
IDD(TIM)
16-bit Timer supply current 1)
Parameter
VDD=5.0 V
Conditions
50
μA
IDD(ART)
ART PWM supply current2)
VDD=5.0 V
75
μA
IDD(SPI)
SPI supply current
3)
VDD=5.0 V
400
μA
IDD(SCI)
SCI supply current 4)
VDD=5.0 V
400
μA
IDD(I2C)
I2C supply current 5)
VDD=5.0 V
175
μA
IDD(ADC)
ADC supply current when converting 6)
VDD=5.0 V
400
μA
Notes:
1. Data based on a differential IDD measurement between reset configuration (timer counter running at fCPU/4) and timer
counter stopped (only TIMD bit set). Data valid for one timer.
2. Data based on a differential IDD measurement between reset configuration (timer stopped) and timer counter enabled
(only TCE bit set).
3. Data based on a differential IDD measurement between reset configuration (SPI disabled) and a permanent SPI master
communication at maximum speed (data sent equal to 55h).This measurement includes the pad toggling consumption.
4. Data based on a differential IDD measurement between SCI low power state (SCID=1) and a permanent SCI data transmit sequence.
5. Data based on a differential IDD measurement between reset configuration (I2C disabled) and a permanent I2C master
communication at 100 kHz (data sent equal to 55h). This measurement include the pad toggling consumption
(27 kOhm external pull-up on clock and data lines).
6. Data based on a differential IDD measurement between reset configuration and continuous A/D conversions.
141/175
ST72321M6 ST72321M9
11.5 CLOCK AND TIMING CHARACTERISTICS
Subject to general operating conditions for VDD, fCPU, and TA.
11.5.1 General Timings
Symbol
tc(INST)
tv(IT)
Parameter
Conditions
Instruction cycle time
Interrupt reaction time
tv(IT) = Δtc(INST) + 10
fCPU=8 MHz
2)
fCPU=8 MHz
Min
Typ 1)
Max
Unit
2
3
12
tCPU
250
375
1500
ns
10
22
tCPU
1.25
2.75
μs
Max
Unit
11.5.2 External Clock Source
Symbol
Parameter
Conditions
Min
Typ
VOSC1H
OSC1 input pin high level voltage
0.7xVDD
VDD
VOSC1L
OSC1 input pin low level voltage
VSS
0.3xVDD
tw(OSC1H)
tw(OSC1L)
OSC1 high or low time 3)
tr(OSC1)
tf(OSC1)
OSC1 rise or fall time 3)
IL
see Figure 73
V
5
ns
15
VSS ≤VIN≤VDD
OSC1 Input leakage current
±1
μA
Figure 73. Typical Application with an External Clock Source
90%
VOSC1H
10%
VOSC1L
tr(OSC1)
tf(OSC1)
OSC2
tw(OSC1H)
tw(OSC1L)
Not connected internally
fOSC
EXTERNAL
CLOCK SOURCE
OSC1
IL
ST72XXX
Notes:
1. Data based on typical application software.
2. Time measured between interrupt event and interrupt vector fetch. Δtc(INST) is the number of tCPU cycles needed to finish
the current instruction execution.
3. Data based on design simulation and/or technology characteristics, not tested in production.
142/175
ST72321M6 ST72321M9
CLOCK AND TIMING CHARACTERISTICS (Cont’d)
11.5.3 Crystal and Ceramic Resonator Oscillators
The ST7 internal clock can be supplied with four
different Crystal/Ceramic resonator oscillators. All
the information given in this paragraph is based on
characterization results with specified typical external components. In the application, the resonator and the load capacitors have to be placed as
Symbol
Parameter
fOSC
Oscillator Frequency 1)
RF
Feedback resistor2)
CL1
CL2
Symbol
i2
close as possible to the oscillator pins in order to
minimize output distortion and start-up stabilization time. Refer to the crystal/ceramic resonator
manufacturer for more details (frequency, package, accuracy...).
Conditions
Recommended load capacitance versus equivalent serial resistance of the
crystal or ceramic resonator (RS)
Parameter
OSC2 driving current
Min
Max
Unit
LP: Low power oscillator
MP: Medium power oscillator
MS: Medium speed oscillator
HS: High speed oscillator
1
>2
>4
>8
2
4
8
16
MHz
20
40
kΩ
RS=200 Ω
RS=200 Ω
RS=200 Ω
RS=100 Ω
22
22
18
15
56
46
33
33
pF
Typ
Max
Unit
80
160
310
610
150
250
460
910
μA
LP oscillator
MP oscillator
MS oscillator
HS oscillator
Conditions
VDD=5 V
VIN=VSS
LP oscillator
MP oscillator
MS oscillator
HS oscillator
Notes:
1. The oscillator selection can be optimized in terms of supply current using an high quality resonator with small RS value.
Refer to crystal/ceramic resonator manufacturer for more details.
2. Data based on characterisation results, not tested in production.
143/175
ST72321M6 ST72321M9
CLOCK AND TIMING CHARACTERISTICS (Cont’d)
Murata
Supplier
fOSC
Typical Ceramic Resonators1)
(MHz)
Reference2)
Recommended OSCRANGE
Option bit configuration
2
CSTCC2M00G56A-R0
MP Mode3)
4
CSTCR4M00G55B-R0
MS Mode
8
CSTCE8M00G55A-R0
HS Mode
16
CSTCE16M0G53A-R0
HS Mode
Notes:
1. Resonator characteristics given by the ceramic resonator manufacturer.
2. SMD = [-R0: Plastic tape package (∅ =180 mm), -B0: Bulk]
LEAD = [-A0: Flat pack package (Radial taping Ho= 18 mm), -B0: Bulk]
3. LP mode is not recommended for 2 MHz resonator because the peak to peak amplitude is too small (>0.8 V)
For more information on these resonators, please consult www.murata.com
144/175
ST72321M6 ST72321M9
CLOCK CHARACTERISTICS (Cont’d)
11.5.4 RC Oscillators
Symbol
fOSC (RCINT)
Parameter
Conditions
Internal RC oscillator frequency
TA=25 °C, VDD=5 V
See Figure 74
Figure 74. Typical fOSC(RCINT) vs TA
fOSC(RCINT) (MHz)
Vdd = 5V
Vdd = 5.5V
3.6
3.4
3.2
3
-45
0
25
TA(°C)
145/175
70
Typ
Max
Unit
2
3.5
5.6
MHz
Note: To reduce disturbance to the RC oscillator,
it is recommended to place decoupling capacitors
between VDD and VSS as shown in Figure 94
4
3.8
Min
130
ST72321M6 ST72321M9
CLOCK CHARACTERISTICS (Cont’d)
Note:
1. Data based on characterization results.
11.5.5 PLL Characteristics
Symbol
Parameter
fOSC
Conditions
PLL input frequency range
Min
Typ
2
Δ fCPU/ fCPU Instantaneous PLL jitter 1)
Max
Unit
4
MHz
fOSC = 4 MHz.
1.0
2.5
fOSC = 2 MHz.
2.5
4.0
%
Note:
1. Data characterized but not tested.
The user must take the PLL jitter into account in the application (for example in serial communication or
sampling of high frequency signals). The PLL jitter is a periodic effect, which is integrated over several
CPU cycles. Therefore the longer the period of the application signal, the less it will be impacted by the
PLL jitter.
Figure 75 shows the PLL jitter integrated on application signals in the range 125 kHz to 4 MHz. At frequencies of less than 125 kHz, the jitter is negligible.
Figure 75. Integrated PLL Jitter vs signal frequency1
+/-Jitter (%)
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
4 MHz
2 MHz
1 MHz
500 kHz
250 kHz
Application Frequency
+/-Jitter (%)
1.2
FLASH typ
1
ROM max
ROM typ
0.8
0.6
0.4
0.2
0
4 MHz
2 MHz
1 MHz 500 kHz 250 kHz 125 kHz
Application Frequency
Note 1: Measurement conditions: fCPU = 8 MHz.
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ST72321M6 ST72321M9
11.6 MEMORY CHARACTERISTICS
11.6.1 RAM and Hardware Registers
Symbol
VRM
Parameter
Data retention mode
1)
Conditions
Halt mode (or RESET)
Min
Typ
Max
1.6
Unit
V
11.6.2 Flash memory
DUAL VOLTAGE HDFlash MEMORY
Symbol
Parameter
fCPU
Operating frequency
VPP
Programming voltage 3)
IDD
current4)
Supply
IPP
VPP current4)
tVPP
Internal VPP stabilization time
tRET
Data retention
NRW
Write erase cycles
TPROG
TERASE
Programming or erasing temperature range
Conditions
Read mode
Write / Erase mode
4.5 V ≤VDD ≤ 5.5 V
RUN mode
(fCPU = 4 MHz)
Write / Erase
Power down mode / Halt
Read (VPP=12 V)
Write / Erase
Min 2)
0
1
11.4
Typ
Max 2)
8
8
12.6
3
0
1
10
200
30
10
TA=85 °C
TA=105 °C
TA=125 °C
TA= 55 °C
TA= 85 °C
40
15
7
1000
100
-40
Unit
MHz
V
mA
µA
mA
µs
years
cycles
cycles
25
85
°C
Notes:
1. Minimum VDD supply voltage without losing data stored in RAM (in Halt mode or under RESET) or in hardware registers
(only in Halt mode). Not tested in production.
2. Data based on characterization results, not tested in production.
3. VPP must be applied only during the programming or erasing operation and not permanently for reliability reasons.
4. Data based on simulation results, not tested in production.
Warning: Do not connect 12 V to VPP before VDD is powered on, as this may damage the device.
147/175
ST72321M6 ST72321M9
11.7 EMC CHARACTERISTICS
Susceptibility tests are performed on a sample basis during product characterization.
11.7.1 Functional EMS (Electro Magnetic
Susceptibility)
Based on a simple running application on the
product (toggling 2 LEDs through I/O ports), the
product is stressed by two electro magnetic events
until a failure occurs (indicated by the LEDs).
■ ESD: Electro-Static Discharge (positive and
negative) is applied on all pins of the device until
a functional disturbance occurs. This test
conforms with the IEC 1000-4-2 standard.
■ FTB: A Burst of Fast Transient voltage (positive
and negative) is applied to VDD and VSS through
a 100pF capacitor, until a functional disturbance
occurs. This test conforms with the IEC 1000-44 standard.
A device reset allows normal operations to be resumed. The test results are given in the table below based on the EMS levels and classes defined
in application note AN1709.
11.7.1.1 Designing hardened software to avoid
noise problems
EMC characterization and optimization are performed at component level with a typical applicaSymbol
Parameter
tion environment and simplified MCU software. It
should be noted that good EMC performance is
highly dependent on the user application and the
software in particular.
Therefore it is recommended that the user applies
EMC software optimization and prequalification
tests in relation with the EMC level requested for
his application.
Software recommendations:
The software flowchart must include the management of runaway conditions such as:
– Corrupted program counter
– Unexpected reset
– Critical Data corruption (control registers...)
Prequalification trials:
Most of the common failures (unexpected reset
and program counter corruption) can be reproduced by manually forcing a low state on the RESET pin or the Oscillator pins for 1 second.
To complete these trials, ESD stress can be applied directly on the device, over the range of
specification values. When unexpected behaviour
is detected, the software can be hardened to prevent unrecoverable errors occurring (see application note AN1015).
Conditions
Level/
Class
VFESD
Voltage limits to be applied on any I/O pin to induce a VDD=5 V, TA=+25 °C, LQFP64,
functional disturbance
fOSC=8 MHz, conforms to IEC 1000-4-2
4B
VFFTB
Fast transient voltage burst limits to be applied
V =5 V, TA=+25 °C, fOSC=8 MHz,
through 100 pF on VDD and VDD pins to induce a func- DD
LQFP64, conforms to IEC 1000-4-4
tional disturbance
3B
148/175
ST72321M6 ST72321M9
EMC CHARACTERISTICS (Cont’d)
11.7.2 Electro Magnetic Interference (EMI)
Based on a simple application running on the
product (toggling 2 LEDs through the I/O ports),
the product is monitored in terms of emission. This
emission test is in line with the norm SAE J 1752/
3 which specifies the board and the loading of
each pin.
Symbol
SEMI
Parameter
Peak level
Conditions
60 Kbytes Flash Devices 2:
VDD=5 V, TA=+25 °C,
LQFP64 package
conforming to SAE J 1752/3
Monitored
Frequency Band
15
15
30 MHz to 130 MHz
20
27
130 MHz to 1 GHz
0
5
2.5
3
SAE EMI Level
Unit
8/4 MHz 16/8 MHz
0.1 MHz to 30 MHz
Notes:
1. Data based on characterization results, not tested in production.
2. Refer to Application Note AN1709 for data on other package types.
149/175
Max vs. [fOSC/fCPU]1
dBμV
-
ST72321M6 ST72321M9
EMC CHARACTERISTICS (Cont’d)
11.7.3 Absolute Maximum Ratings (Electrical
Sensitivity)
Based on three different tests (ESD and LU) using
specific measurement methods, the product is
stressed in order to determine its performance in
terms of electrical sensitivity. For more details, refer to the application note AN1181.
11.7.3.1 Electro-Static Discharge (ESD)
Electro-Static Discharges (a positive then a negative pulse separated by 1 second) are applied to
the pins of each sample according to each pin
combination. The sample size depends on the
number of supply pins in the device (3 parts*(n+1)
supply pin). Two models can be simulated: Human
Body Model and Machine Model. This test conforms to the JESD22-A114A/A115A standard.
Absolute Maximum Ratings
Symbol
VESD(HBM)
Ratings
Electro-static discharge voltage
(Human Body Model)
Conditions
TA=+25 °C
Maximum value 1) Unit
2000
V
Notes:
1. Data based on characterization results, not tested in production.
11.7.3.2 Static and Dynamic Latch-Up
■ LU: 2 complementary static tests are required
on 6 parts to assess the latch-up performance.
A supply overvoltage (applied to each power
supply pin) and a current injection (applied to
each input, output and configurable I/O pin) are
performed on each sample. This test conforms
to the EIA/JESD 78 IC latch-up standard.
Electrical Sensitivities
Symbol
LU
150/175
Parameter
Static latch-up class
Conditions
TA=+125 °C
conforming to JESD 78
Class
II level A
ST72321M6 ST72321M9
11.8 I/O PORT PIN CHARACTERISTICS
11.8.1 General Characteristics
Subject to general operating conditions for VDD, fOSC, and TA unless otherwise specified.
Symbol
Parameter
Conditions
VIL
Input low level voltage
VIH
Input high level voltage 1)
Vhys
Schmitt trigger voltage hysteresis 2)
VIL
Input low level voltage 1)
VIH
Input high level voltage 1)
Vhys
Schmitt trigger voltage hysteresis 2)
IINJ(PIN)3)
Typ
0.7
V
0.8
TTL ports
2
1
Injected Current on PC6
0
Injected Current on an I/O pin
+4
±4
VDD=5 V
VSS≤VIN≤VDD
Input leakage current
mA
± 25
±1
Static current consumption
Floating input
RPU
Weak pull-up equivalent resistor 5)
VIN=VSS
VDD=5 V
CIO
I/O pin capacitance
5
Output high to low level fall time 1)
25
tf(IO)out
Unit
0.7xVDD
mode4)
IS
Max
0.3xVDD
CMOS ports
Total injected current (sum of all I/O
ΣIINJ(PIN)3)
and control pins)
IL
Min
1)
tr(IO)out
CL=50 pF
Output low to high level rise time 1) Between 10% and 90%
tw(IT)in
External interrupt pulse time 6)
Figure 76. Unused I/O Pins configured as input
μA
400
50
120
250
kΩ
pF
ns
25
1
tCPU
Figure 77. Typical IPU vs. VDD with VIN=VSS
90
VDD
ST7XXX
Ta=140°C
80
Ta=95°C
10kΩ
70
Ta=25°C
UNUSED I/O PORT
Ta=-45°C
UNUSED I/O PORT
10kΩ
Ipu(uA )
60
50
40
30
ST7XXX
Note: I/O can be left unconnected if it is configured as output
(0 or 1) by the software. This has the advantage of
greater EMC robustness and lower cost.
20
10
0
2
2.5
3
3.5
4
4.5
V dd(V)
5
5.5
6
Notes:
1. Data based on characterization results, not tested in production.
2. Hysteresis voltage between Schmitt trigger switching levels. Based on characterization results, not tested.
3. When the current limitation is not possible, the VIN maximum must be respected, otherwise refer to IINJ(PIN) specification. A positive injection is induced by VIN>VDD while a negative injection is induced by VIN<VSS. Refer to section 11.2.2
on page 135 for more details.
4. Configuration not recommended, all unused pins must be kept at a fixed voltage: using the output mode of the I/O for
example and leaving the I/O unconnected on the board or an external pull-up or pull-down resistor (see Figure 76). Data
based on design simulation and/or technology characteristics, not tested in production.
5. The RPU pull-up equivalent resistor is based on a resistive transistor (corresponding IPU current characteristics described in Figure 77).
6. To generate an external interrupt, a minimum pulse width has to be applied on an I/O port pin configured as an external
interrupt source.
151/175
ST72321M6 ST72321M9
I/O PORT PIN CHARACTERISTICS (Cont’d)
11.8.2 Output Driving Current
Subject to general operating conditions for VDD, fCPU, and TA unless otherwise specified.
Symbol
Parameter
Conditions
VOL 1)
Output low level voltage for a high sink I/O pin
when 4 pins are sunk at same time
(see Figure 79 and Figure 81)
VDD=5 V
Output low level voltage for a standard I/O pin
when 8 pins are sunk at same time
(see Figure 78)
Output high level voltage for an I/O pin
when 4 pins are sourced at same time
(see Figure 80 and Figure 83)
VOH 2)
Figure 78. Typical VOL at VDD= 5 V (standard)
Max
IIO=+5 mA
1.2
IIO=+2 mA
0.5
IIO=+20 mA,TA≤85 °C
TA≥85 °C
1.3
1.5
IIO=+8 mA
0.6
IIO=-5 mA, TA≤85 °C
TA≥85 °C
VDD-1.4
VDD-1.6
IIO=-2 mA
VDD-0.7
Unit
V
Figure 80. Typical VOH at VDD= 5 V
1.4
5.5
1.2
5
1
V dd-Voh (V) at Vdd=5V
V ol (V ) at Vdd=5V
Min
0.8
0.6
Ta =14 0°C "
0.4
Ta =95 °C
Ta =25 °C
0.2
3.5
V dd= 5V 1 40°C m in
3
V dd= 5v 95°C m in
2.5
0
0.005
4
V dd= 5v 25°C m in
Ta =-45 °C
0
4.5
0.01
0.015
Iio(A)
V dd= 5v -4 5°C m in
2
-0.01
-0.008 -0.006 -0.004
-0.002
0
Figure 79. Typical VOL at VDD= 5 V (high-sink)
1
0.9
V ol(V ) at Vdd=5V
0.8
0.7
0.6
0.5
0.4
Ta= 140 °C
0.3
Ta= 95 °C
0.2
Ta= 25 °C
0.1
Ta= -45°C
0
0
0.01
0.02
0.03
Iio(A)
Notes:
1. The IIO current sunk must always respect the absolute maximum rating specified in Section 11.2.2 and the sum of IIO
(I/O ports and control pins) must not exceed IVSS.
2. The IIO current sourced must always respect the absolute maximum rating specified in Section 11.2.2 and the sum of
IIO (I/O ports and control pins) must not exceed IVDD. True open drain I/O pins do not have VOH.
152/175
ST72321M6 ST72321M9
I/O PORT PIN CHARACTERISTICS (Cont’d)
Figure 81. Typical VOL vs. VDD (standard)
1
0.45
Ta= -4 5°C
0.9
Ta= 95°C
Ta=2 5°C
Ta=9 5°C
0.35
Ta= 140 °C
0.7
Vol(V) at Iio=2mA
V ol(V ) at Iio=5m A
0.8
Ta=-4 5°C
0.4
Ta= 25°C
0.6
0.5
0.4
0.3
Ta=1 40°C
0.3
0.25
0.2
0.15
0.2
0.1
0.1
0.05
0
2
2.5
3
3.5
4
4.5
5
5.5
0
6
2
Vdd(V )
2.5
3
3.5
4
4.5
5
5.5
6
Vdd(V)
Figure 82. Typical VOL vs. VDD (high-sink)
1 .6
0 .6
Ta = 140 °C
1 .4
0 .5
Ta =95 °C
1 .2
Ta =25 °C
Ta =-45°C
Vol(V ) at Iio=20m A
Vol(V ) at Iio=8m A
0 .4
0 .3
0 .2
1
0 .8
0 .6
Ta= 14 0°C
0 .4
Ta=9 5°C
0 .1
Ta=2 5°C
0 .2
Ta=-45 °C
0
0
2
2.5
3
3.5
4
4.5
5
5.5
2
6
2.5
3
3.5
4
4.5
5
5.5
6
V dd(V )
V dd (V )
Figure 83. Typical VDD-VOH vs. VDD
5.5
6
Ta= -4 5°C
5
4.5
Vdd-Voh(V) at Iio=-5mA
Vdd-Voh(V) at Iio=-2m A
5
4
3.5
Ta= -4 5°C
3
Ta= 25°C
Ta= 95°C
Ta= 140°C
4
3
2
Ta= 95°C
2.5
1
Ta= 140°C
2
2
2.5
3
3.5
4
Vdd(V)
153/175
Ta= 25°C
4.5
5
5.5
6
0
2
2.5
3
3.5
4
Vdd(V)
4.5
5
5.5
6
ST72321M6 ST72321M9
11.9 CONTROL PIN CHARACTERISTICS
11.9.1 Asynchronous RESET Pin
Subject to general operating conditions for VDD, fCPU, and TA unless otherwise specified.
Symbol
Parameter
Conditions
VIL
Input low level voltage
VIH
Input high level voltage 1)
Vhys
Schmitt trigger voltage hysteresis 2)
VOL
Output low level voltage 3)
IIO
RON
Min
Typ
1)
0.16xVDD
0.85xVDD
2.5
VDD=5 V IIO=+2 mA
0.2
Input current on RESET pin
tw(RSTL)out Generated reset pulse duration
External reset pulse hold time
tg(RSTL)in
Filtered glitch duration 5)
0.5
2
Weak pull-up equivalent resistor
th(RSTL)in
Max
4)
20
Stretch applied on
external pulse
0
Internal reset sources
20
30
30
Unit
V
V
mA
120
kΩ
426)
μs
426)
μs
μs
2.5
200
ns
Notes:
1. Data based on characterization results, not tested in production.
2. Hysteresis voltage between Schmitt trigger switching levels.
3. The IIO current sunk must always respect the absolute maximum rating specified in Section 11.2.2 and the sum of IIO
(I/O ports and control pins) must not exceed IVSS.
4. To guarantee the reset of the device, a minimum pulse has to be applied to the RESET pin. All short pulses applied on
the RESET pin with a duration below th(RSTL)in can be ignored.
5. The reset network (the resistor and two capacitors) protects the device against parasitic resets, especially in noisy environments.
6. Data guaranteed by design, not tested in production.
154/175
ST72321M6 ST72321M9
CONTROL PIN CHARACTERISTICS (Cont’d)
Figure 84. RESET pin protection when LVD is enabled.1)2)3)4)
VDD
Required
Optional
(note 3)
ST72XXX
RON
EXTERNAL
RESET
INTERNAL
RESET
Filter
0.01μF
1 MΩ
PULSE
GENERATOR
WATCHDOG
LVD RESET
Figure 85. RESET pin protection when LVD is disabled.1)
Recommended for EMC
VDD
USER
EXTERNAL
RESET
CIRCUIT
VDD
ST72XXX
VDD
0.01 μF
4.7 kΩ
RON
INTERNAL
RESET
Filter
0.01 μF
PULSE
GENERATOR
WATCHDOG
Required
Note 1:
– The reset network protects the device against parasitic resets.
– The output of the external reset circuit must have an open-drain output to drive the ST7 reset pad. Otherwise the
device can be damaged when the ST7 generates an internal reset (LVD or watchdog).
– Whatever the reset source is (internal or external), the user must ensure that the level on the RESET pin can go
below the VIL max. level specified in section 11.9.1 on page 154. Otherwise the reset will not be taken into account
internally.
– Because the reset circuit is designed to allow the internal RESET to be output in the RESET pin, the user must ensure that the current sunk on the RESET pin is less than the absolute maximum value specified for IINJ(RESET) in
section 11.2.2 on page 135.
Note 2: When the LVD is enabled, it is recommended not to connect a pull-up resistor or capacitor. A 10nF pull-down
capacitor is required to filter noise on the reset line.
Note 3: In case a capacitive power supply is used, it is recommended to connect a 1 MΩ pull-down resistor to the RESET
pin to discharge any residual voltage induced by the capacitive effect of the power supply (this will add 5 µA to the power
consumption of the MCU).
Note 4: Tips when using the LVD:
– 1. Check that all recommendations related to reset circuit have been applied (see notes above).
– 2. Check that the power supply is properly decoupled (100 nF + 10 µF close to the MCU). Refer to AN1709 and
AN2017. If this cannot be done, it is recommended to put a 100 nF + 1 MΩ pull-down on the RESET pin.
– 3. The capacitors connected on the RESET pin and also the power supply are key to avoid any start-up marginality.
In most cases, steps 1 and 2 above are sufficient for a robust solution. Otherwise: replace 10nF pull-down on the
RESET pin with a 5 µF to 20 µF capacitor.
155/175
ST72321M6 ST72321M9
CONTROL PIN CHARACTERISTICS (Cont’d)
11.9.2 ICCSEL/VPP Pin
Subject to general operating conditions for VDD, fCPU, and TA unless otherwise specified.
Symbol
Parameter
VIL
Input low level voltage
VIH
Input high level voltage 1)
IL
Input leakage current
Min
Max1
Unit
VSS
0.2
V
VDD-0.1
12.6
Conditions
1)
VIN=VSS
±1
μA
Note:
1. Data based on design simulation and/or technology characteristics, not tested in production.
Figure 86. Two typical Applications with ICCSEL/VPP Pin 1)
ICCSEL/VPP
ST72XXX
VPP
PROGRAMMING
TOOL
10kΩ
Note:
1. When ICC mode is not required by the application ICCSEL/VPP pin must be tied to VSS.
156/175
ST72XXX
ST72321M6 ST72321M9
11.10 TIMER PERIPHERAL CHARACTERISTICS
Subject to general operating conditions for VDD, fOSC, and TA unless otherwise specified.
Refer to I/O port characteristics for more details on the input/output alternate function characteristics (output compare, input capture, external clock, PWM output...).
11.10.1 8-Bit PWM-ART Auto-Reload Timer
Symbol
Parameter
tres(PWM) PWM resolution time
Conditions
fCPU=8 MHz
Min
Typ
Max
1
tCPU
125
ns
fEXT
ART external clock frequency
0
fCPU/2
fPWM
PWM repetition rate
0
fCPU/2
ResPWM
VOS
PWM resolution
PWM/DAC output step voltage
Unit
8
VDD=5 V, Res=8-bits
20
MHz
bit
mV
11.10.2 16-Bit Timer
Symbol
Parameter
Conditions
tw(ICAP)in Input capture pulse time
tres(PWM) PWM resolution time
fCPU=8 MHz
Min
Typ
Max
Unit
1
tCPU
2
tCPU
250
ns
fEXT
Timer external clock frequency
0
fCPU/4
MHz
fPWM
PWM repetition rate
0
fCPU/4
MHz
16
bit
ResPWM
157/175
PWM resolution
ST72321M6 ST72321M9
11.11 COMMUNICATION INTERFACE CHARACTERISTICS
11.11.1 SPI - Serial Peripheral Interface
Subject to general operating conditions for VDD,
fCPU, and TA unless otherwise specified.
Symbol
Refer to I/O port characteristics for more details on
the input/output alternate function characteristics
(SS, SCK, MOSI, MISO).
Parameter
Conditions
Master
fSCK
1/tc(SCK)
fCPU=8 MHz
SPI clock frequency
Slave
fCPU=8 MHz
tr(SCK)
tf(SCK)
SPI clock rise and fall time
tsu(SS)
SS setup time
th(SS)
Min
Max
fCPU/128
0.0625
fCPU/4
2
0
fCPU/2
4
120
SS hold time
Slave
120
SCK high and low time
Master
Slave
100
90
tsu(MI)
tsu(SI)
Data input setup time
Master
Slave
100
100
th(MI)
th(SI)
Data input hold time
Master
Slave
100
100
ta(SO)
Data output access time
Slave
0
tdis(SO)
Data output disable time
Slave
tv(SO)
Data output valid time
th(SO)
Data output hold time
tv(MO)
Data output valid time
th(MO)
Data output hold time
MHz
see I/O port pin description
Slave
tw(SCKH)
tw(SCKL)
Unit
ns
120
240
90
Slave (after enable edge)
0
Master (before capture edge)
0.25
tCPU
0.25
Figure 87. SPI Slave Timing Diagram with CPHA=0 3)
SS INPUT
SCK INPUT
tsu(SS)
tc(SCK)
th(SS)
CPHA=0
CPOL=0
CPHA=0
CPOL=1
ta(SO)
MISO OUTPUT
tw(SCKH)
tw(SCKL)
MSB OUT
see note 2
tsu(SI)
MOSI INPUT
tv(SO)
th(SO)
BIT6 OUT
tdis(SO)
tr(SCK)
tf(SCK)
LSB OUT
see
note 2
th(SI)
MSB IN
BIT1 IN
LSB IN
Notes:
1. Data based on design simulation and/or characterisation results, not tested in production.
2. When no communication is on-going the data output line of the SPI (MOSI in master mode, MISO in slave mode) has
its alternate function capability released. In this case, the pin status depends on the I/O port configuration.
3. Measurement points are done at CMOS levels: 0.3xVDD and 0.7xVDD.
158/175
ST72321M6 ST72321M9
COMMUNICATION INTERFACE CHARACTERISTICS (Cont’d)
Figure 88. SPI Slave Timing Diagram with CPHA=11)
SS INPUT
SCK INPUT
tsu(SS)
tc(SCK)
th(SS)
CPHA=1
CPOL=0
CPHA=1
CPOL=1
tw(SCKH)
tw(SCKL)
ta(SO)
MISO OUTPUT
see
note 2
tv(SO)
th(SO)
MSB OUT
HZ
tsu(SI)
BIT6 OUT
LSB OUT
see
note 2
th(SI)
MSB IN
MOSI INPUT
tdis(SO)
tr(SCK)
tf(SCK)
BIT1 IN
LSB IN
Figure 89. SPI Master Timing Diagram 1)
SS INPUT
tc(SCK)
SCK INPUT
CPHA=0
CPOL=0
CPHA=0
CPOL=1
CPHA=1
CPOL=0
CPHA=1
CPOL=1
tw(SCKH)
tw(SCKL)
tsu(MI)
MISO INPUT
MOSI OUTPUT
th(MI)
MSB IN
tv(MO)
see note 2
tr(SCK)
tf(SCK)
BIT6 IN
LSB IN
th(MO)
MSB OUT
BIT6 OUT
LSB OUT
see note 2
Notes:
1. Measurement points are done at CMOS levels: 0.3xVDD and 0.7xVDD.
2. When no communication is on-going the data output line of the SPI (MOSI in master mode, MISO in slave mode) has
its alternate function capability released. In this case, the pin status depends of the I/O port configuration.
159/175
ST72321M6 ST72321M9
COMMUNICATION INTERFACE CHARACTERISTICS (Cont’d)
11.11.2 I2C - Inter IC Control Interface
Subject to general operating conditions for VDD,
fCPU, and TA unless otherwise specified.
Symbol
Refer to I/O port characteristics for more details on
the input/output alternate function characteristics
(SDAI and SCLI). The ST7 I2C interface meets the
requirements of the Standard I2C communication
protocol described in the following table.
Standard mode I2C
Parameter
Min 1)
Fast mode I2C5)
Max 1)
Min 1)
Max 1)
tw(SCLL)
SCL clock low time
4.7
1.3
tw(SCLH)
SCL clock high time
4.0
0.6
tsu(SDA)
SDA setup time
250
100
3)
0 2)
900 3)
0
μs
th(SDA)
SDA data hold time
tr(SDA)
tr(SCL)
SDA and SCL rise time
1000
20+0.1Cb
300
tf(SDA)
tf(SCL)
SDA and SCL fall time
300
20+0.1Cb
300
th(STA)
START condition hold time
4.0
0.6
tsu(STA)
Repeated START condition setup time
4.7
0.6
tsu(STO)
STOP condition setup time
4.0
0.6
tw(STO:STA) STOP to START condition time (bus free)
4.7
Capacitive load for each bus line
Cb
Unit
ns
μs
μs
μs
1.3
400
400
pF
Figure 90. Typical Application with I2C Bus and Timing Diagram 4)
VDD
4.7kΩ
I2C
VDD
4.7kΩ
BUS
100Ω
SDAI
100Ω
SCLI
ST72XXX
REPEATED START
START
tsu(STA)
tw(STO:STA)
START
SDA
tr(SDA)
tf(SDA)
tsu(SDA)
STOP
th(SDA)
SCK
th(STA)
tw(SCKH)
tw(SCKL)
tr(SCK)
tf(SCK)
tsu(STO)
Notes:
1. Data based on standard I2C protocol requirement, not tested in production.
2. The device must internally provide a hold time of at least 300 ns for the SDA signal in order to bridge the undefined
region of the falling edge of SCL.
3. The maximum hold time of the START condition has only to be met if the interface does not stretch the low period of
SCL signal.
4. Measurement points are done at CMOS levels: 0.3xVDD and 0.7xVDD.
5. At 4 MHz fCPU, max.I2C speed (400 kHz) is not achievable. In this case, max. I2C speed will be approximately 260 kHz.
160/175
ST72321M6 ST72321M9
COMMUNICATION INTERFACE CHARACTERISTICS (Cont’d)
The following table gives the values to be written in
the I2CCCR register to obtain the required I2C
SCL line frequency.
Table 26. SCL Frequency Table
I2CCCR Value
fSCL
(kHz)
400
300
200
100
50
20
fCPU=4 MHz.
VDD = 4.1 V
RP=3.3 kΩ RP=4.7 kΩ
NA
NA
NA
NA
83h
83h
10h
10h
24h
24h
5Fh
5Fh
VDD = 5 V
RP=3.3 kΩ RP=4.7 kΩ
NA
NA
NA
NA
83h
83h
10h
10h
24h
24h
5Fh
5Fh
fCPU=8 MHz.
VDD = 4.1 V
VDD = 5 V
RP=3.3 kΩ RP=4.7 kΩ RP=3.3 kΩ RP=4.7 kΩ
83h
83
83h
83h
85h
85h
85h
85h
8Ah
89h
8Ah
8Ah
24h
23h
24h
23h
4Ch
4Ch
4Ch
4Ch
FFh
FFh
FFh
FFh
Legend:
RP = External pull-up resistance
fSCL = I2C speed
NA = Not achievable
Note:
– For speeds around 200 kHz, achieved speed can have ±5% tolerance
– For other speed ranges, achieved speed can have ±2% tolerance
The above variations depend on the accuracy of the external components used.
161/175
ST72321M6 ST72321M9
11.12 10-BIT ADC CHARACTERISTICS
Subject to general operating conditions for VDD, fCPU, and TA unless otherwise specified.
Symbol
fADC
VAREF
VAIN
Parameter
Conditions
ADC clock frequency
0.7*VDD ≤VAREF ≤VDD
Analog reference voltage
Conversion voltage range
1)
Min
Max
Unit
0.4
Typ
2
MHz
3.8
VDD
VSSA
VAREF
Positive input leakage current for analog -40 °C≤TA≤ 85 °C range
input
Other TA ranges
Ilkg
Negative input leakage current on robust analog pins 2
RAIN
External input impedance
CAIN
External capacitor on analog input
fAIN
Variation freq. of analog input signal
VIN<VSS, | IIN |< 400 µA
on adjacent robust analog pin
V
±250
nA
±1
μA
See note 2
see
Figure 91
and
Figure 92
kΩ
pF
Hz
CADC
Internal sample and hold capacitor
12
pF
tADC
Conversion time (Sample+Hold)
fCPU=8 MHz, SPEED=0 fADC=2 MHz
7.5
μs
tADC
- No of sample capacitor loading cycles
- No. of Hold conversion cycles
4
11
1/fADC
Notes:
1. Any added external serial resistor will downgrade the ADC accuracy (especially for resistance greater than 10 kΩ).
Data based on characterization results, not tested in production.
2. Injecting negative current on any of the analog input pins significantly reduces the accuracy of any conversion being
performed on any analog input. Analog pins of Flash devices can be protected against negative injection by adding a
Schottky diode (pin to ground). Injecting negative current on digital input pins degrades ADC accuracy especially if performed on a pin close to the analog input pins. Any positive injection current within the limits specified for IINJ(PIN) and
ΣIINJ(PIN) in Section 11.8 does not affect the ADC accuracy.
162/175
ST72321M6 ST72321M9
ADC CHARACTERISTICS (Cont’d)
Figure 91. RAIN max. vs fADC with CAIN=0pF1)
Figure 92. Recommended CAIN & RAIN values.2)
45
1000
Cain 10 nF
2 MHz
35
30
1 MHz
25
Cain 22 nF
100
Max. R AIN (Kohm)
Max. R AIN (Kohm)
40
20
15
10
Cain 47 nF
10
1
5
0
0.1
0
10
30
70
0.01
0.1
CPARASITIC (pF)
1
10
fAIN(KHz)
Figure 93. Typical A/D Converter Application
VDD
RAIN
AINx
ST72XXX
VT
0.6 V
2 kΩ(max)
VAIN
CAIN
VT
0.6 V
IL
±1μA
10-Bit A/D
Conversion
CADC
12 pF
Notes:
1. CPARASITIC represents the capacitance of the PCB (dependent on soldering and PCB layout quality) plus the pad capacitance (3 pF). A high CPARASITIC value will downgrade conversion accuracy. To remedy this, fADC should be reduced.
2. This graph shows that depending on the input signal variation (fAIN), CAIN can be increased for stabilization time and
decreased to allow the use of a larger serial resistor (RAIN).
163/175
ST72321M6 ST72321M9
ADC CHARACTERISTICS (Cont’d)
11.12.1 Analog Power Supply and Reference
Pins
Depending on the MCU pin count, the package
may feature separate VAREF and VSSA analog
power supply pins. These pins supply power to the
A/D converter cell and function as the high and low
reference voltages for the conversion.
Separation of the digital and analog power pins allow board designers to improve A/D performance.
Conversion accuracy can be impacted by voltage
drops and noise in the event of heavily loaded or
badly decoupled power supply lines (see Section
11.12.2 General PCB Design Guidelines).
11.12.2 General PCB Design Guidelines
To obtain best results, some general design and
layout rules should be followed when designing
the application PCB to shield the noise-sensitive,
analog physical interface from noise-generating
CMOS logic signals.
– Use separate digital and analog planes. The analog ground plane should be connected to the
digital ground plane via a single point on the
PCB.
– Filter power to the analog power planes. It is recommended to connect capacitors, with good high
frequency characteristics, between the power
and ground lines, placing 0.1µF and optionally, if
needed 10 pF capacitors as close as possible to
the ST7 power supply pins and a 1 to 10µF capacitor close to the power source (see Figure
94).
– The analog and digital power supplies should be
connected in a star network. Do not use a resistor, as VAREF is used as a reference voltage by
the A/D converter and any resistance would
cause a voltage drop and a loss of accuracy.
– Properly place components and route the signal
traces on the PCB to shield the analog inputs.
Analog signals paths should run over the analog
ground plane and be as short as possible. Isolate
analog signals from digital signals that may
switch while the analog inputs are being sampled
by the A/D converter. Do not toggle digital outputs on the same I/O port as the A/D input being
converted.
Figure 94. Power Supply Filtering
ST72XXX
1 to 10 μF
0.1μF
ST7
DIGITAL NOISE
FILTERING
VSS
VDD
VDD
POWER
SUPPLY
SOURCE
0.1 μF
EXTERNAL
NOISE
FILTERING
164/175
VAREF
VSSA
ST72321M6 ST72321M9
10-BIT ADC CHARACTERISTICS (Cont’d)
11.12.3 ADC Accuracy
Conditions: VDD=5 V 1)
Symbol
|ET|
|EO|
|EG|
Typ
Max2)
3
4
2
3
0.5
3
CPU in run mode @ fADC 2 MHz.
1
2
CPU in run mode @ fADC 2 MHz.
1
2
Parameter
Total unadjusted error
Offset error
Gain Error
Conditions
1)
1)
1)
|ED|
Differential linearity error
|EL|
Integral linearity error 1)
1)
Unit
LSB
Notes:
1. ADC Accuracy vs. Negative Injection Current: Injecting negative current may reduce the accuracy of the conversion
being performed on another analog input. The effect of negative injection current on robust pins is specified in Section
11.12.
Any positive injection current within the limits specified for IINJ(PIN) and ΣIINJ(PIN) in Section 11.8 does not affect the ADC
accuracy.
2. Data based on characterization results, monitored in production to guarantee 99.73 % within ± max value from -40 °C
to 125 °C (± 3σ distribution limits).
Figure 95. ADC Accuracy Characteristics
Digital Result ADCDR
EG
1023
1022
1LSB
1021
IDEAL
V
–V
AREF
SSA
= --------------------------------------------
1024
(2)
ET
ET=Total Unadjusted Error: maximum deviation
between the actual and the ideal transfer curves.
EO=Offset Error: deviation between the first actual
transition and the first ideal one.
EG=Gain Error: deviation between the last ideal
transition and the last actual one.
ED=Differential Linearity Error: maximum deviation
between actual steps and the ideal one.
EL=Integral Linearity Error: maximum deviation
between any actual transition and the end point
correlation line.
(3)
7
(1)
6
5
EO
4
(1) Example of an actual transfer curve
(2) The ideal transfer curve
(3) End point correlation line
EL
3
ED
2
1 LSBIDEAL
1
0
1
VSSA
165/175
Vin (LSBIDEAL)
2
3
4
5
6
7
1021 1022 1023 1024
VAREF
ST72321M6 ST72321M9
12 PACKAGE CHARACTERISTICS
12.1 ECOPACK
In order to meet environmental requirements, ST
offers these devices in different grades of ECOPACK® packages, depending on their level of environmental compliance. ECOPACK® specifica-
tions, grade definitions and product status are
available at: www.st.com. ECOPACK® is an ST
trademark.
12.2 PACKAGE MECHANICAL DATA
Figure 96. 80-Pin Low Profile Quad Flat Package
Dim.
D
Min
Typ
A
A
D1
A2
inches1)
mm
Max
Min
Typ
Max
1.60
0.0630
0.15 0.0020
0.0059
A1
0.05
A2
1.35 1.40 1.45 0.0531 0.0551 0.0571
b
0.22 0.32 0.38 0.0087 0.0126 0.0150
C
0.09
A1
b
e
E1
E
0.6299
D1
14.00
0.5512
E
16.00
0.6299
E1
14.00
0.5512
0.65
θ
c
L
h
0.0079
16.00
e
L1
0.20 0.0035
D
L
0°
3.5°
0.0256
7°
0°
3.5°
7°
0.45 0.60 0.75 0.0177 0.0236 0.0295
L1
1.00
0.0394
Number of Pins
N
80
Note 1. Values in inches are converted from
mm and rounded to 4 decimal digits.
12.3 THERMAL CHARACTERISTICS
Symbol
RthJA
PD
TJmax
Ratings
Value
Unit
55
°C/W
Power dissipation 1)
500
mW
Maximum junction temperature 2)
150
°C
Package thermal resistance (junction to ambient)
TQFP80 14x14
Notes:
1. The power dissipation is obtained from the formula PD=PINT+PPORT where PINT is the chip internal power (IDDxVDD)
and PPORT is the port power dissipation determined by the user.
2. The average chip-junction temperature can be obtained from the formula TJ = TA + PD x RthJA.
166/175
ST72321M6 ST72321M9
13 ST72321Mx DEVICE CONFIGURATION AND ORDERING INFORMATION
Each device is available for production in user programmable versions (Flash).
Flash devices are shipped to customers with a default content. This implies that Flash devices have
to be configured by the customer using the Option
Bytes.
13.1 FLASH OPTION BYTES
STATIC OPTION BYTE 0
STATIC OPTION BYTE 1
PKG1
RSTC
1
0
0
1
1
1
1
1
The option bytes allow the hardware configuration
of the microcontroller to be selected. They have no
address in the memory map and can be accessed
only in programming mode (for example using a
standard ST7 programming tool). The default content of the Flash is fixed to FFh. To program the
Flash devices directly using ICP, Flash devices
are shipped to customers with the internal RC
clock source.
OPTION BYTE 0
OPT7= WDG HALT Watchdog and Halt mode
This option bit determines if a RESET is generated
when entering Halt mode while the Watchdog is
active.
0: No Reset generation when entering Halt mode
1: Reset generation when entering Halt mode
OPT6= WDG SW Hardware or software watchdog
This option bit selects the watchdog type.
0: Hardware (watchdog always enabled)
167/175
OSCTYPE
OSCRANGE
1
0
2
1
0
PLLOFF
0
FMP_R
SW
1
Res.
HALT
1
0
1
VD
WDG
Default
7
PKG0
0
Reserved
7
1
0
1
1
1
1
1: Software (watchdog to be enabled by software)
OPT5 = Reserved, must be kept at default value.
OPT4:3= VD[1:0] Voltage detection
These option bits enable the voltage detection
block (LVD, and AVD) with a selected threshold for
the LVD and AVD (EVD+AVD).
Selected Low Voltage Detector
LVD and AVD Off
Lowest Threshold: (VDD~3 V)
Med. Threshold (VDD~3.5 V)
Highest Threshold (VDD~4 V)
VD1
VD0
1
1
0
0
1
0
1
0
Caution: If the medium or low thresholds are selected, the detection may occur outside the specified operating voltage range. Below 3.8V, device
operation is not guaranteed.
ST72321M6 ST72321M9
ST72321Mx DEVICE CONFIGURATION AND ORDERING INFORMATION (Cont’d)
OPT2 = Reserved, must be kept at default value.
OPT1= PKG0 Package selection bit 0
This option bit is used to select the package (see
table in PKG1 option bit description).
OPT0= FMP_R Flash memory read-out protection
Read-out protection, when selected, provides a
protection against Program Memory content extraction and against write access to Flash memory.
Erasing the option bytes when the FMP_R option
is selected causes the whole user memory to be
erased first, and the device can be reprogrammed.
Refer to the ST7 Flash Programming Reference
Manual for more details.
Note: Readout protection is not supported if LVD
is enabled.
0: Read-out protection enabled
1: Read-out protection disabled
OPT5:4 = OSCTYPE[1:0] Oscillator Type
These option bits select the ST7 main clock
source type.
OSCTYPE
Clock Source
1
0
Resonator Oscillator
0
0
Reserved
0
1
Internal RC Oscillator
1
0
External Source
1
1
OPT3:1 = OSCRANGE[2:0] Oscillator range
When the resonator oscillator type is selected,
these option bits select the resonator oscillator
current source corresponding to the frequency
range of the used resonator. Otherwise, these bits
are used to select the normal operating frequency
range.
OSCRANGE
OPTION BYTE 1
OPT7= PKG1 Package selection bit 1
This option bit, with the PKG0 bit, selects the package.
Version
Selected Package
M
LQFP80
PKG 1 PKG 0
1
1
Note: On the chip, each I/O port has 8 pads. Pads
that are not bonded to external pins are in input
pull-up configuration after reset. The configuration
of these pads must be kept at reset state to avoid
added current consumption.
OPT6 = RSTC RESET clock cycle selection
This option bit selects the number of CPU cycles
applied during the RESET phase and when exiting
Halt mode. For resonator oscillators, it is advised
to select 4096 due to the long crystal stabilization
time.
0: Reset phase with 4096 CPU cycles
1: Reset phase with 256 CPU cycles
168/175
Typ. Freq. Range
2
1
0
LP
1~2 MHz
0
0
0
MP
2~4 MHz
0
0
1
MS
4~8 MHz
0
1
0
HS
8~16 MHz
0
1
1
OPT0 = PLLOFF PLL activation
This option bit activates the PLL which allows multiplication by two of the main input clock frequency.
The PLL must not be used with the internal RC oscillator or with external clock source. The PLL is
guaranteed only with an input frequency between
2 and 4 MHz.
0: PLL x2 enabled
1: PLL x2 disabled
CAUTION: the PLL can be enabled only if the
“OSC RANGE” (OPT3:1) bits are configured to
“MP - 2~4 MHz”. Otherwise, the device functionality is not guaranteed.
ST72321M6 ST72321M9
ST72321xx DEVICE CONFIGURATION AND ORDERING INFORMATION (Cont’d)
13.2 DEVICE ORDERING INFORMATION
Figure 97. Ordering information scheme
Example:
ST72
F
321
M
6
T
6
Family
ST7 microcontroller family
Memory type
F: Flash
Sub-family
321 (Flash)
No. of pins
M = 80
Memory size
6 = 32 Kbytes
9 = 60 Kbytes
Package
T = LQFP
Temperature range
6 = -40 °C to 85 °C
For a list of available options (e.g. memory size, package) and orderable part numbers or for further information
on any aspect of this device, please contact the ST Sales Office nearest to you.
169/175
ST72321M6 ST72321M9
14 KNOWN LIMITATIONS
14.1 Safe Connection of OSC1/OSC2 Pins
The OSC1 and/or OSC2 pins must not be left unconnected otherwise the ST7 main oscillator may
start and, in this configuration, could generate an
fOSC clock frequency in excess of the allowed
maximum (>16 MHz.), putting the ST7 in an unsafe/undefined state. Refer to section 6.2 on page
24.
lead to occurrence of same interrupt twice (one
hardware and another with software call).
To avoid this, a semaphore is set to '1' before
checking the level change. The semaphore is
changed to level '0' inside the interrupt routine.
When a level change is detected, the semaphore
status is checked and if it is '1' this means that the
last interrupt has been missed. In this case, the interrupt routine is invoked with the call instruction.
14.2 Reset pin protection with LVD Enabled
As mentioned in note 2 below Figure 84 on page
155, when the LVD is enabled, it is recommended
not to connect a pull-up resistor or capacitor. A
10 nF pull-down capacitor is required to filter noise
on the reset line.
14.3 Unexpected Reset Fetch
If an interrupt request occurs while a “POP CC” instruction is executed, the interrupt controller does
not recognise the source of the interrupt and, by
default, passes the RESET vector address to the
CPU.
Workaround
To solve this issue, a “POP CC” instruction must
always be preceded by a “SIM” instruction.
14.4 External interrupt missed
To avoid any risk if generating a parasitic interrupt,
the edge detector is automatically disabled for one
clock cycle during an access to either DDR and
OR. Any input signal edge during this period will
not be detected and will not generate an interrupt.
This case can typically occur if the application refreshes the port configuration registers at intervals
during runtime.
Workaround
The workaround is based on software checking
the level on the interrupt pin before and after writing to the PxOR or PxDDR registers. If there is a
level change (depending on the sensitivity programmed for this pin) the interrupt routine is invoked using the call instruction with three extra
PUSH instructions before executing the interrupt
routine (this is to make the call compatible with the
IRET instruction at the end of the interrupt service
routine).
But detection of the level change does not make
sure that edge occurs during the critical 1 cycle duration and the interrupt has been missed. This may
170/175
There is another possible case i.e. if writing to
PxOR or PxDDR is done with global interrupts disabled (interrupt mask bit set). In this case, the
semaphore is changed to '1' when the level
change is detected. Detecting a missed interrupt is
done after the global interrupts are enabled (interrupt mask bit reset) and by checking the status of
the semaphore. If it is '1' this means that the last
interrupt was missed and the interrupt routine is invoked with the call instruction.
To implement the workaround, the following software sequence is to be followed for writing into the
PxOR/PxDDR registers. The example is for for
Port PF1 with falling edge interrupt sensitivity. The
software sequence is given for both cases (global
interrupt disabled/enabled).
Case 1: Writing to PxOR or PxDDR with Global Interrupts Enabled:
LD A,#01
LD sema,A
; set the semaphore to '1'
LD A,PFDR
AND A,#02
LD X,A
; store the level before writing to
PxOR/PxDDR
LD A,#$90
LD PFDDR,A ; Write to PFDDR
LD A,#$ff
LD PFOR,A ; Write to PFOR
LD A,PFDR
AND A,#02
LD Y,A
; store the level after writing to
PxOR/PxDDR
LD A,X
; check for falling edge
cp A,#02
jrne OUT
TNZ Y
jrne OUT
ST72321M6 ST72321M9
LD A,sema
; check the semaphore status if
edge is detected
CP A,#01
jrne OUT
call call_routine; call the interrupt routine
OUT:LD A,#00
LD sema,A
.call_routine ; entry to call_routine
PUSH A
PUSH X
PUSH CC
.ext1_rt
; entry to interrupt routine
LD A,#00
LD sema,A
IRET
Case 2: Writing to PxOR or PxDDR with Global Interrupts Disabled:
SIM
; set the interrupt mask
LD A,PFDR
AND A,#$02
LD X,A
; store the level before writing to
PxOR/PxDDR
LD A,#$90
LD PFDDR,A; Write into PFDDR
LD A,#$ff
LD PFOR,A
; Write to PFOR
LD A,PFDR
AND A,#$02
LD Y,A
; store the level after writing to PxOR/
PxDDR
LD A,X
; check for falling edge
cp A,#$02
jrne OUT
TNZ Y
jrne OUT
LD A,#$01
LD sema,A ; set the semaphore to '1' if edge is
detected
RIM
; reset the interrupt mask
LD A,sema ; check the semaphore status
CP A,#$01
jrne OUT
call call_routine; call the interrupt routine
171/175
RIM
OUT:
RIM
JP while_loop
.call_routine ; entry to call_routine
PUSH A
PUSH X
PUSH CC
.ext1_rt
; entry to interrupt routine
LD A,#$00
LD sema,A
IRET
14.5 Clearing active
interrupt routine
interrupts
outside
When an active interrupt request occurs at the
same time as the related flag is being cleared, an
unwanted reset may occur.
Note: clearing the related interrupt mask will not
generate an unwanted reset
Concurrent interrupt context
The symptom does not occur when the interrupts
are handled normally, i.e.
when:
– The interrupt flag is cleared within its own interrupt routine
– The interrupt flag is cleared within any interrupt
routine
– The interrupt flag is cleared in any part of the
code while this interrupt is disabled
If these conditions are not met, the symptom can
be avoided by implementing the following sequence:
Perform SIM and RIM operation before and after
resetting an active interrupt request.
Example:
SIM
reset interrupt flag
RIM
Nested interrupt context:
The symptom does not occur when the interrupts
are handled normally, i.e.
when:
– The interrupt flag is cleared within its own interrupt routine
– The interrupt flag is cleared within any interrupt
routine with higher or identical priority level
ST72321M6 ST72321M9
– The interrupt flag is cleared in any part of the
code while this interrupt is disabled
If these conditions are not met, the symptom can
be avoided by implementing the following sequence:
PUSH CC
SIM
reset interrupt flag
POP CC
14.6 SCI Wrong Break duration
Description
A single break character is sent by setting and resetting the SBK bit in the SCICR2 register. In
some cases, the break character may have a longer duration than expected:
- 20 bits instead of 10 bits if M=0
- 22 bits instead of 11 bits if M=1.
In the same way, as long as the SBK bit is set,
break characters are sent to the TDO pin. This
may lead to generate one break more than expected.
Occurrence
The occurrence of the problem is random and proportional to the baudrate. With a transmit frequency of 19200 baud (fCPU=8 MHz and SCIBRR=0xC9), the wrong break duration occurrence
is around 1%.
Workaround
If this wrong duration is not compliant with the
communication protocol in the application, software can request that an Idle line be generated
before the break character. In this case, the break
duration is always correct assuming the application is not doing anything between the idle and the
break. This can be ensured by temporarily disabling interrupts.
The exact sequence is:
- Disable interrupts
- Reset and Set TE (IDLE request)
- Set and Reset SBK (Break Request)
- Re-enable interrupts
14.7 16-bit Timer PWM Mode
In PWM mode, the first PWM pulse is missed after
writing the value FFFCh in the OC1R register
(OC1HR, OC1LR). It leads to either full or no PWM
during a period, depending on the OLVL1 and
OLVL2 settings.
172/175
14.8 TIMD set simultaneously with OC interrupt
If the 16-bit timer is disabled at the same time the
output compare event occurs then output compare
flag gets locked and cannot be cleared before the
timer is enabled again.
Impact on the application
If output compare interrupt is enabled, then the
output compare flag cannot be cleared in the timer
interrupt routine. Consequently the interrupt service routine is called repeatedly.
Workaround
Disable the timer interrupt before disabling the timer. Again while enabling, first enable the timer then
the timer interrupts.
Perform the following to disable the timer:
TACR1 or TBCR1 = 0x00h; // Disable the compare interrupt
TACSR | or TBCSR | = 0x40; // Disable the timer
Perform the following to enable the timer again:
TACSR & or TBCSR &= ~0x40; // Enable the
timer
TACR1 or TBCR1 = 0x40; // Enable the compare
interrupt
14.9 I2C Multimaster
In multimaster configurations, if the ST7 I2C receives a START condition from another I2C master after the START bit is set in the I2CCR register
and before the START condition is generated by
the ST7 I2C, it may ignore the START condition
from the other I2C master. In this case, the ST7
master will receive a NACK from the other device.
On reception of the NACK, ST7 can send a re-start
and Slave address to re-initiate communication
14.10 Internal RC Oscillator with LVD
The internal RC can only be used if LVD is enabled.
14.11 I/O behaviour during ICC mode entry
sequence
Symptom
Both Port G and H are forced to output push-pull
during ICC mode entry sequence.
Details
To enable programming of all Flash sectors, the
device must leave USER mode and be configured
ST72321M6 ST72321M9
in ICC mode. Once in ICC mode, the ICC protocol
enables an ST7 microcontroller to communicate
with an external controller (such as a PC). ICC
mode is entered by applying 39 pulses on the ICCDATA signal during reset. To enter ICC mode,
the device goes through other modes, some
modes are critical because the I/Os PG[7:0] and
PH[7:0] are forced to output push-pull.
Impact on the Application
The PG and PH I/O ports are forced to output
push-pull during three pulses on ICCDATA. In certain circumstances, this behaviour can lead to a
173/175
short-circuit between the I/O signals and VDD, VSS
or an output signal of another application component.
In addition, switching these I/Os to output mode
can cause the application to leave reset state, disturbing the ICC communication and preventing the
user from programming the Flash.
14.12 Read-out protection with LVD
The LVD is not supported if Readout protection is
enabled.
ST72321M6 ST72321M9
15 REVISION HISTORY
Table 27. Revision History
Date
Revision
26-Sep-2006
1
Initial release
2
Modified title of the document
Removed references to ROM devices
Modified HDFlash endurance and data retention on first page
Modified Table 1 on page 1
Added note 2 to Table 2 on page 9
Modified “Starting the Conversion” on page 125
Modified tRET and NRW values in “Flash memory” on page 147
Modified “Absolute Maximum Ratings (Electrical Sensitivity)” on page 150 (removed
VESD(MM))
Modified “Electro Magnetic Interference (EMI)” on page 149
Modified conditions for VFESD and VFFTB in “Functional EMS (Electro Magnetic Susceptibility)” on page 148 (LQFP64 added)
Added Section 12.1 “ECOPACK” on page 166
Values in inches rounded to 4 decimal digits (instead of 3) in “PACKAGE MECHANICAL DATA” on page 166
Added “TIMD set simultaneously with OC interrupt” on page 172
Modified Section 13 ST72321Mx DEVICE CONFIGURATION AND ORDERING INFORMATION
Removed products with a -40 to 125 °C temperature range
Removed option list
04-May-2009
174/175
Description of Changes
ST72321M6 ST72321M9
Please Read Carefully:
Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the
right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any
time, without notice.
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