ST ST7LITE49K2 User Manual

Download

8-bit MCU with single voltage Flash memory,

LQFP32

7 x 7

PDIP32S

data EEPROM, ADC, 8/12/16-bit timers, SPI and I²C interface

Features

■ Memories

– 8 Kbytes single voltage extended Flash

(XFlash) program memory with Read-out protection In-circuit programming and in-application programming (ICP and IAP) Endurance: 10K write/erase cycles guaranteed

Data retention: 20 years at 55 °C – 384 bytes RAM – 256 bytes data EEPROM with Read-Out

Protection.

300K write/erase cycles guaranteed,

data retention: 20 years at 55 °C.

■ Clock, Reset and Supply Management

– Low voltage supervisor (LVD) for safe

power-on/off – Clock sources: Internal trimmable 8 MHz

RC oscillator, auto-wakeup internal low

power - low frequency oscillator,

crystal/ceramic resonator or external clock – Five power saving modes: Halt, Active-halt,

Auto-wakeup from Halt, Wait and Slow – Internal 32-MHz input clock for Autoreload

timer

■ I/O Ports

– Up to 24 multifunctional bidirectional I/Os – 8 high sink outputs

■ 6 timers

– Configurable watchdog timer – Dual 8-bit Lite timers with prescaler,

1 real time base and 1 input capture – Dual 12-bit Autoreload timers with 4 PWM

outputs, input capture, output compare,

dead-time generation and enhanced one

pulse mode functions

ST7LITE49K2

■ Communication interfaces:

– I²C multimaster interface – SPI synchronous serial interface

■ 2 analog comparators

– Internal voltage reference module

■ A/D Converter

– 10 input channels – Fixed gain Op-amp

■ Interrupt management

– 13 interrupt vectors plus TRAP and RESET

■ Instruction set

– 8-bit data manipulation – 63 basic instructions with illegal opcode

detection – 17 main addressing modes – 8 x 8 unsigned multiply instructions

■ Development tools

– Full HW/SW development package – DM (Debug module)

February 2009 Rev 4 1/245

www.st.com

Contents ST7LITE49K2

Contents

1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

2 Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

3 Register and memory mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

4 Flash programmable memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

4.2 Main features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

4.3 Programming modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

4.3.1 In-circuit programming (ICP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

4.3.2 In-application programming (IAP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

4.4 ICC interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

4.5 Memory protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

4.5.1 Read-out protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

4.5.2 Flash write/erase protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

4.6 Related documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

4.7 Description of Flash control/status register (FCSR) . . . . . . . . . . . . . . . . . 28

5 Data EEPROM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

5.2 Main features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

5.3 Memory access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

5.3.1 Read operation (E2LAT=0) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

5.3.2 Write operation (E2LAT=1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

5.4 Power saving modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

5.4.1 Wait mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

5.4.2 Active-halt mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

5.4.3 Halt mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

5.5 Access error handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

5.6 Data EEPROM read-out protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

5.7 EEPROM control/status register (EECSR) . . . . . . . . . . . . . . . . . . . . . . . . 32

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6 Central processing unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

6.2 Main features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

6.3 CPU registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

6.3.1 Accumulator (A) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

6.3.2 Index registers (X and Y) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

6.3.3 Program counter (PC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

6.3.4 Condition code register (CC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

6.3.5 Stack pointer (SP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

7 Supply, reset and clock management . . . . . . . . . . . . . . . . . . . . . . . . . . 38

7.1 RC oscillator adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

7.1.1 Internal RC oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

7.1.2 Auto-wakeup RC oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

7.2 Multi-oscillator (MO) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

7.2.1 External clock source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

7.2.2 Crystal/ceramic oscillators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

7.2.3 Internal RC oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

7.3 Reset sequence manager (RSM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

7.3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

7.3.2 Asynchronous external RESET pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

7.3.3 External power-on reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

7.3.4 Internal low voltage detector (LVD) reset . . . . . . . . . . . . . . . . . . . . . . . . 45

7.3.5 Internal watchdog reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

7.4 System integrity management (SI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

7.4.1 Low voltage detector (LVD) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

7.4.2 Auxiliary voltage detector (AVD) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

7.4.3 Low power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

7.5 Register description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

7.5.1 Main clock control/status register (MCCSR) . . . . . . . . . . . . . . . . . . . . . 50

7.5.2 RC control register (RCCR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

7.5.3 System integrity (SI) control/status register (SICSR) . . . . . . . . . . . . . . . 51

7.5.4 AVD threshold selection register (AVDTHCR) . . . . . . . . . . . . . . . . . . . . 52

7.5.5 Clock controller control/status register (CKCNTCSR) . . . . . . . . . . . . . . 53

8 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

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Contents ST7LITE49K2

8.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

8.2 Masking and processing flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

8.2.1 Servicing pending interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

8.2.2 Interrupt vector sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

8.3 Interrupts and low power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

8.4 Concurrent and nested management . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

8.5 Description of interrupt registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

8.5.1 CPU CC register interrupt bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

8.5.2 Interrupt software priority registers (ISPRx) . . . . . . . . . . . . . . . . . . . . . . 59

8.5.3 External interrupt control register (EICR) . . . . . . . . . . . . . . . . . . . . . . . . 62

9 Power saving modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

9.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

9.2 Slow mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

9.3 Wait mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

9.4 Active-halt and Halt modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

9.4.1 Active-halt mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

9.4.2 Halt mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

9.5 Auto-wakeup from Halt mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

9.5.1 Register description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

9.5.2 AWUFH control/status register (AWUCSR) . . . . . . . . . . . . . . . . . . . . . . 72

9.5.3 AWUFH prescaler register (AWUPR) . . . . . . . . . . . . . . . . . . . . . . . . . . 73

10 I/O ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

10.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

10.2 Functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

10.2.1 Input modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

10.2.2 Output modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

10.2.3 Alternate functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

10.2.4 Analog alternate function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

10.3 I/O port implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

10.4 Unused I/O pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

10.5 Low power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

10.6 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

10.7 Device-specific I/O port configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

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10.7.1 Standard ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

10.7.2 Other ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

11 On-chip peripherals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

11.1 Watchdog timer (WDG) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

11.1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

11.1.2 Main features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

11.1.3 Functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

11.1.4 Hardware watchdog option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

11.1.5 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

11.1.6 Register description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

11.2 Dual 12-bit autoreload timer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

11.2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

11.2.2 Main features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

11.2.3 Functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

11.2.4 Low power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

11.2.5 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

11.2.6 Register description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

11.3 Lite timer 2 (LT2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

11.3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

11.3.2 Main features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

11.3.3 Functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110

11.3.4 Low power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

11.3.5 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

11.3.6 Register description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

11.4 16-bit timer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

11.4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

11.4.2 Main features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

11.4.3 Functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

11.4.4 Low power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129

11.4.5 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130

11.4.6 Summary of 16-bit timer modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130

11.4.7 16-bit timer registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131

11.4.8 16-bit timer register map and reset values . . . . . . . . . . . . . . . . . . . . . . 137

11.5 I2C bus interface (I2C) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139

11.5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139

11.5.2 Main features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139

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11.5.3 General description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139

11.5.4 Functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142

Slave mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142

Master mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144

11.5.5 Low power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147

11.5.6 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147

11.5.7 Register description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148

11.6 Serial peripheral interface (SPI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156

11.6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156

11.6.2 Main Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156

11.6.3 General description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156

11.6.4 Functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157

11.6.5 Clock phase and clock polarity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161

11.6.6 Error flags . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162

11.6.7 Low power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165

11.6.8 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165

11.6.9 Register description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166

11.7 10-bit A/D converter (ADC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171

11.7.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171

11.7.2 Main features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171

11.7.3 Functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171

11.7.4 Low power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173

11.7.5 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173

11.7.6 Register description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174

11.8 Analog comparator (CMP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177

11.8.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177

11.8.2 Main features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177

11.8.3 Functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178

11.8.4 Register description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179

12 Instruction set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183

12.1 ST7 addressing modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183

12.1.1 Inherent mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184

12.1.2 Immediate mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185

12.1.3 Direct modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185

12.1.4 Indexed modes (no offset, short, long) . . . . . . . . . . . . . . . . . . . . . . . . 185

12.1.5 Indirect modes (short, long) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186

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12.1.6 Indirect indexed modes (short, long) . . . . . . . . . . . . . . . . . . . . . . . . . . 186

12.1.7 Relative modes (direct, indirect) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187

12.2 Instruction groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188

12.2.1 Illegal opcode reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189

13 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192

13.1 Parameter conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192

13.1.1 Minimum and maximum values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192

13.1.2 Typical values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192

13.1.3 Typical curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192

13.1.4 Loading capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192

13.1.5 Pin input voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192

13.2 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193

13.3 Operating conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195

13.3.1 General operating conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195

13.3.2 Operating conditions with low voltage detector (LVD) . . . . . . . . . . . . . 195

13.3.3 Auxiliary voltage detector (AVD) thresholds . . . . . . . . . . . . . . . . . . . . . 196

13.3.4 Voltage drop between AVD flag setting and LVD reset generation . . . 196

13.3.5 Internal RC oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197

13.4 Supply current characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200

13.4.1 Supply current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200

13.4.2 On-chip peripherals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203

13.5 Communication interface characteristics . . . . . . . . . . . . . . . . . . . . . . . . 203

13.5.1 I2C interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203

13.5.2 SPI interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205

13.6 Clock and timing characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207

13.6.1 Auto-wakeup from Halt oscillator (AWU) . . . . . . . . . . . . . . . . . . . . . . . 208

13.6.2 Crystal and ceramic resonator oscillators . . . . . . . . . . . . . . . . . . . . . . 209

13.6.3 32-MHz PLL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210

13.7 Memory characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211

13.8 EMC (electromagnetic compatibility) characteristics . . . . . . . . . . . . . . . 212

13.8.1 Functional EMS (electromagnetic susceptibility) . . . . . . . . . . . . . . . . . 212

13.8.2 EMI (electromagnetic interference) . . . . . . . . . . . . . . . . . . . . . . . . . . . 213

13.8.3 Absolute maximum ratings (electrical sensitivity) . . . . . . . . . . . . . . . . 213

13.9 I/O port pin characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214

13.9.1 General characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214

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13.9.2 Output driving current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216

13.10 Control pin characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224

13.10.1 Asynchronous RESET pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224

13.11 10-bit ADC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226

13.11.1 Amplifier output offset variation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229

13.12 Analog comparator characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229

14 Device configuration and ordering information . . . . . . . . . . . . . . . . . 230

14.1 Option bytes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230

14.1.1 Option byte 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230

14.1.2 Option byte 0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231

14.2 Device ordering information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233

14.3 Transfer of customer code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234

14.4 Development tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236

14.4.1 Starter kits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236

14.4.2 Development and debugging tools . . . . . . . . . . . . . . . . . . . . . . . . . . . 236

14.4.3 Programming tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236

14.4.4 Order codes for development and programming tools . . . . . . . . . . . . . 236

14.5 ST7 application notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237

15 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241

15.1 Thermal characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243

16 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244

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List of tables

Table 1. ST7LITE49K2 device summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Table 2. ST7LITE49K2 device pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Table 3. Hardware register map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Table 4. Interrupt software priority truth table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Table 5. Predefined RC oscillator calibration values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Table 6. ST7 clock sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Table 7. CPU clock delay during Reset sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Table 8. Low power modes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Table 9. Description of interrupt events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Table 10. Reset source selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Table 11. Internal RC prescaler selection bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Table 12. AVD threshold selection bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Table 13. Clock register mapping and reset values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Table 14. Interrupt software priority levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

Table 15. Setting the interrupt software priority . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

Table 16. Interrupt vector vs ISPRx bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

Table 17. Dedicated interrupt instruction set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

Table 18. ST7LITE49K2 interrupt mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Table 19. Interrupt sensitivity bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

Table 20. Enabling/disabling Active-halt and Halt modes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

Table 21. Configuring the dividing factor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

Table 22. AWU register mapping and reset values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

Table 23. DR value and output pin status. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

Table 24. I/O port mode options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

Table 25. I/O port configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

Table 26. Effect of low power modes on I/O ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

Table 27. Description of interrupt events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

Table 28. PA5:0, PB7:0, PC7:4 and PC2:0 pins. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

Table 29. PA7:6 pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

Table 30. PC3 pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

Table 31. Port configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

Table 32. I/O port register mapping and reset values. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

Table 33. Watchdog timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

Table 34. Watchdog timer register mapping and reset values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

Table 35. Effect of low power modes on autoreload timer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

Table 36. Description of interrupt events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

Table 37. Counter clock selection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

Table 38. Register mapping and reset values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

Table 39. Effect of low power modes on Lite timer 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

Table 40. Description of interrupt events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

Table 41. Lite timer register mapping and reset values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

Table 42. Effect of low power modes on 16-bit timer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129

Table 43. 16-bit timer interrupt control/wakeup capability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130

Table 44. Summary of 16-bit timer modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130

Table 45. 16-bit timer register map and reset values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137

Table 46. Effect of low power modes on the I

Table 47. Description of interrupt events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147

Table 48. Configuration of I

C delay times . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154

C interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147

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Table 49. I2C register mapping and reset values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155

Table 50. Low power mode descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165

Table 51. Interrupt events. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165

Table 52. SPI Master mode SCK Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167

Table 53. SPI Register Map and Reset Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170

Table 54. Effect of low power modes on the A/D converter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173

Table 55. Channel selection using CH[3:0] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174

Table 56. Configuring the ADC clock speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175

Table 57. ADC register mapping and reset values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176

Table 58. Comparison result. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177

Table 59. Voltage reference programming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180

Table 60. Analog comparator register map and reset values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182

Table 61. Description of addressing modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183

Table 62. ST7 addressing mode overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183

Table 63. Instructions supporting inherent addressing mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184

Table 64. Instructions supporting inherent immediate addressing mode . . . . . . . . . . . . . . . . . . . . . 185

Table 65. Instructions supporting direct, indexed, indirect and indirect indexed addressing modes 186

Table 66. Instructions supporting relative modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187

Table 67. ST7 instruction set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188

Table 68. Illegal opcode detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189

Table 69. Voltage characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193

Table 70. Current characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194

Table 71. Thermal characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194

Table 72. General operating conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195

Table 73. Operating characteristics with LVD. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195

Table 74. Operating characteristics with AVD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196

Table 75. Voltage drop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196

Table 76. Internal RC oscillator characteristics (5.0 V calibration) . . . . . . . . . . . . . . . . . . . . . . . . . . 197

Table 77. Internal RC oscillator characteristics (3.3 V calibration) . . . . . . . . . . . . . . . . . . . . . . . . . . 198

Table 78. Supply current characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200

Table 79. On-chip peripheral characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203

Table 80. I Table 81. SCL frequency (multimaster I

C interface characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203

C interface) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204

Table 82. SPI interface characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205

Table 83. General timings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207

Table 84. External clock source characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208

Table 85. AWU from Halt characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208

Table 86. Crystal/ceramic resonator oscillator characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209

Table 87. Typical ceramic resonators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209

Table 88. 32-MHz PLL characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210

Table 89. RAM and hardware registers characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211

Table 90. Flash program memory characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211

Table 91. Data EEPROM memory characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211

Table 92. EMS test results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212

Table 93. EMI emissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213

Table 94. ESD absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213

Table 95. Electrical sensitivities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214

Table 96. General characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214

Table 97. Output driving current characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216

Table 98. Asynchronous RESET pin characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224

Table 99. ADC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226

Table 100. ADC accuracy with VDD = 3.3 to 5.5 V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227

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Table 101. ADC accuracy with VDD = 2.7 to 3.3 V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227

Table 102. ADC accuracy with VDD = 2.4 to 2.7 V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227

Table 103. Amplifier characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228

Table 104. Offset variation at TA = 25 °C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229

Table 105. Analog comparator characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229

Table 106. Startup clock selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230

Table 107. LVD threshold configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230

Table 108. Selection of the resonator oscillator range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231

Table 109. Configuration of sector size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232

Table 110. Development tool order codes for the ST7LITE49K2 family. . . . . . . . . . . . . . . . . . . . . . . 237

Table 111. ST7 application notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237

Table 112. 32-pin plastic dual in-line package, shrink 400-mil width, mechanical data . . . . . . . . . . . 241

Table 113. 32-pin low profile quad flat package (7x7), package mechanical data . . . . . . . . . . . . . . . 242

Table 114. Thermal characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243

Table 115. Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244

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List of figures ST7LITE49K2

List of figures

Figure 1. ST7LITE49K2 general block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Figure 2. 32-pin SDIP package pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Figure 3. 32-pin LQFP 7x7 package pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Figure 4. ST7LITE49K2 memory map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Figure 5. Typical ICC Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Figure 6. EEPROM block diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Figure 7. Data EEPROM programming flowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Figure 8. Data EEPROM write operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Figure 9. Data EEPROM programming cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Figure 10. CPU registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Figure 11. Stack manipulation example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Figure 12. Clock switching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Figure 13. Clock management block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Figure 14. Reset sequence phases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Figure 15. Reset block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Figure 16. Reset sequences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Figure 17. Low voltage detector vs reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Figure 18. Reset and supply management block diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Figure 19. Using the AVD to monitor VDD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Figure 20. Interrupt processing flowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

Figure 21. Priority decision process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

Figure 22. Concurrent interrupt management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Figure 23. Nested interrupt management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Figure 24. Power saving mode transitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Figure 25. Slow mode clock transition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

Figure 26. Wait mode flowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

Figure 27. Active-halt timing overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

Figure 28. Active-halt mode flowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

Figure 29. Halt timing overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

Figure 30. Halt mode flowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

Figure 31. AWUFH mode block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Figure 32. AWUF Halt timing diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

Figure 33. AWUFH mode flowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Figure 34. I/O port general block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

Figure 35. Interrupt I/O port state transitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

Figure 36. Watchdog block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

Figure 37. Single timer mode (ENCNTR2=0) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

Figure 38. Dual timer mode (ENCNTR2=1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

Figure 39. PWM polarity inversion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

Figure 40. PWM function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

Figure 41. PWM signal from 0% to 100% duty cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

Figure 42. Dead time generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

Figure 43. ST7LITE49K2 block diagram of break function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

Figure 44. Block diagram of output compare mode (single timer) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

Figure 45. Block diagram of input capture mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

Figure 46. Input capture timing diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

Figure 47. Long range input capture block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

Figure 48. Long range input capture timing diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

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Figure 49. Block diagram of one pulse mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

Figure 50. One pulse mode and PWM timing diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

Figure 51. Dynamic DCR2/3 update in one pulse mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

Figure 52. Force overflow timing diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

Figure 53. Lite timer 2 block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

Figure 54. Input capture timing diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110

Figure 55. Timer block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117

Figure 56. 16-bit read sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118

Figure 57. Counter timing diagram, internal clock divided by 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119

Figure 58. Counter timing diagram, internal clock divided by 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119

Figure 59. Counter timing diagram, internal clock divided by 8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119

Figure 60. Input capture block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

Figure 61. Input capture timing diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

Figure 62. Output compare block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124

Figure 63. Output compare timing diagram, f Figure 64. Output compare timing diagram, f

TIMER=fCPU TIMER=fCPU

/2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124

/4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

Figure 65. One pulse mode sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

Figure 66. One pulse mode timing example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

Figure 67. Pulse width modulation mode timing example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

Figure 68. Pulse width modulation cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128

Figure 69. I Figure 70. I

C bus protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140

C interface block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141

Figure 71. Transfer sequencing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146

Figure 72. Event flags and interrupt generation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147

Figure 73. Serial peripheral interface block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157

Figure 74. Single master/ single slave application. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158

Figure 75. Generic SS timing diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159

Figure 76. Hardware/software slave select management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159

Figure 77. Data clock timing diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162

Figure 78. Clearing the WCOL bit (write collision flag) software sequence . . . . . . . . . . . . . . . . . . . . 164

Figure 79. Single master / multiple slave configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165

Figure 80. ST7LITE49K2 ADC block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172

Figure 81. Analog comparator and internal voltage reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178

Figure 82. Analog comparator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179

Figure 83. Pin loading conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192

Figure 84. Pin input voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193

Figure 85. fCPU maximum operating frequency versus VDD

supply voltage . . . . . . . . . . . . . . . . . . 195

Figure 86. Frequency vs voltage at four different ambient temperatures (RC at 5 V) . . . . . . . . . . . . 198

Figure 87. Frequency vs voltage at four different ambient temperatures (RC at 3.3 V). . . . . . . . . . . 199

Figure 88. Accuracy in % vs voltage at 4 different ambient temperatures (RC at 5 V) . . . . . . . . . . . 199

Figure 89. Accuracy in % vs voltage at 4 different ambient temperatures (RC at 3.3V) . . . . . . . . . . 199

Figure 90. Typical IDD in Run vs. fCPU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201

Figure 91. Typical IDD in WFI vs. fCPU. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201

Figure 92. Typical IDD in Slow mode vs. fCPU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201

Figure 93. Typical IDD in Slow-wait mode vs. fCPU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202

Figure 94. Typical IDD vs. temperature at VDD = 5 V and fCPU = 8 MHz . . . . . . . . . . . . . . . . . . . . 202

Figure 95. SPI slave timing diagram with CPHA=0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206

Figure 96. SPI slave timing diagram with CPHA=1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206

Figure 97. SPI master timing diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207

Figure 98. Typical application with an external clock source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208

Figure 99. Typical application with a crystal or ceramic resonator. . . . . . . . . . . . . . . . . . . . . . . . . . . 210

Figure 100. Two typical applications with unused I/O pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215

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List of figures ST7LITE49K2

Figure 101. Rpu resistance versus voltage at four different temperatures . . . . . . . . . . . . . . . . . . . . . . 215

Figure 102. I

current versus voltage at four different temperatures . . . . . . . . . . . . . . . . . . . . . . . . . 215

Figure 103. Typical VOL at VDD = 2.4 V (standard) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217

Figure 104. Typical VOL at VDD = 3 V (standard). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217

Figure 105. Typical VOL at VDD = 5 V (standard). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217

Figure 106. Typical VOL at VDD = 2.4 V (high sink) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218

Figure 107. Typical VOL at VDD = 3 V (high sink). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218

Figure 108. Typical VOL at VDD = 5 V (high sink). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218

Figure 109. Typical VOL vs. VDD at I Figure 110. Typical VOL vs. VDD at I Figure 111. Typical VOL vs VDD at I Figure 112. Typical VOL vs VDD at Figure 113. Typical VOL vs VDD at I

= 2 mA (standard) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219

= 4 mA (standard) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219

= 2 mA (high sink) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219

= 8 mA (high sink) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220

= 12 mA (high sink) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220

Figure 114. Typical VDD-VOH vs. IIO at VDD = 2.4 V (high sink) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220

Figure 115. Typical VDD-VOH vs. IIO at VDD = 3 V (high sink) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221

Figure 116. Typical VDD-VOH vs. IIO at VDD = 5 V (high sink) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221

Figure 117. Typical VDD-VOH vs. IIO at VDD = 2.4 V (standard) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222

Figure 118. Typical VDD-VOH vs. IIO at VDD = 3 V (standard) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222

Figure 119. Typical VDD-VOH vs. IIO at VDD = 5 V (standard) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222

Figure 120. Typical VDD-VOH vs. V

at IIO = 2 mA (high sink) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223

Figure 121. Typical VDD-VOH vs. VDD at IIO = 4 mA (high sink). . . . . . . . . . . . . . . . . . . . . . . . . . . . 223

Figure 122. RESET pin protection when LVD is enabled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225

Figure 123. RESET pin protection when LVD is disabled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226

Figure 124. Typical application with ADC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227

Figure 125. ADC accuracy characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228

Figure 126. ST7LITE49K2 ordering information scheme. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233

Figure 127. 32-pin plastic dual in-line package, shrink 400-mil width, package outline. . . . . . . . . . . . 241

Figure 128. 32-pin low profile quad flat package (7x7), package outline . . . . . . . . . . . . . . . . . . . . . . . 242

14/245

ST7LITE49K2 Description

1 Description

The ST7LITE49K2 is a member of the ST7 microcontroller family. All ST7 devices are based on a common industry-standard 8-bit core, featuring an enhanced instruction set.

The ST7LITE49K2 features Flash memory with byte-by-byte In-Circuit Programming (ICP) and In-Application Programming (IAP) capability.

Under software control, the ST7LITE49K2 device can be placed in Wait, Slow, or Halt mode, reducing power consumption when the application is in idle or standby 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 ST7LITE49K2 features an on-chip Debug Module (DM) to support In-Circuit Debugging (ICD). For a description of the DM registers, refer to the ST7 ICC Protocol Reference Manual.

Table 1. ST7LITE49K2 device summary

Features ST7LITE49K2

Program memory - bytes 8K

RAM (stack) - bytes 384 (128)

Data EEPROM - bytes 256

Operating Supply 2.4 to 5.5 V

CPU Frequency Up to 8 MHz

Operating Temperature -40 to +125 °C

Packages LQFP32, SDIP32

15/245

Description ST7LITE49K2

8-bit core

ALU

ADDRESS AND DATA BUS

RESET

Port A

Control

RAM

(384 Bytes)

PA7:0

(8 bits)

Power supply

Flash

(8 Kbytes)

LVD, AVD

memory

8-bit

Dual Lite Timer

Port B

SPI

PB7:0

(8 bits)

I2C

10-bit ADC

+ OpAmp

12-Bit

Auto-Reload Dual Timer

Watchdog

Debug Module

Programmable

Internal Reference

Comparators

Port C

PC7:0

(8 bits)

program

16-bit Timer

OSC_IN

OSC_OUT

Internal clock

Ext.

1 MHz

Int.

RC OSC

8 MHz

OSC

16 MHz

CLKIN

/ 2

Int.

RC OSC

32 kHz

8 MHz -> 32 MHz

PLL

Data EEPROM

(256 Bytes)

Figure 1. ST7LITE49K2 general block diagram

16/245

ST7LITE49K2 Pin description

ei1

eix associated external interrupt vector

(HS) 20mA high sink capability

ATPWM0/PA2(HS)

COMPOUTA/BREAK1/PC7

PA 0 (H S ) /C O M PI N A -

ATIC/PA1(HS)

ATPWM1/PA3(HS)

I2CCLK/PA7(HS)

RESET

ATPWM3/PA5(HS)

ATPWM2/MCO/PA4(HS)

I 2 CD ATA /PA 6 ( HS )

DDA

PB0/AIN0

PB1/AIN1/CLKIN

OSC1/CLKIN

OSC2

SSA

PB2/AIN2

PB3/AIN3

PC1/AIN9 PC0/AIN8 PB7/AIN7

PB6/AIN6 PB5/AIN5/COMPOUTB PB4/AIN4

PC6/COMPINA+ PC5/COMPINB+/BREAK2 PC4/LTIC/COMPINBPC3/ICCCLK PC2/ICCDATA

ei2

ei0

ei2

Note 1: Available on 8K version only

SSA

DDA

AIN0/PB0

CLKIN/AIN1/PB1

AIN2/PB2

OSC1/CLKIN

OSC2

32 31 30 29 28 27 26 25

24 23 22 21 20 19 18 17

9 10111213141516

1 2 3 4 5 6 7 8

PB6/AIN6/SCK PB5/AIN5/EXTCLK_A/COMPOUTB PB4/AIN4/MISO PB3/AIN3/MOSI

PC2/ICCDATA PC1/AIN9/ICAP2_A PC0/AIN8/ICAP1_A PB7/AIN7/SS

/OCMP2_A

PC6/COMPINA+

PC5/COMPINB+/BREAK2

PC4/LTIC/COMPINB-

PC3/ICCCLK

PA 2( HS ) /AT P W M0

PA 1( HS ) /AT I C

PA0(HS)/OCMP1_A/COMPINA-

PC7/BREAK1

eix associated external interrupt vector

(HS) 20mA high sink capability

I2CCLK/PA7(HS)

RESET

ATPWM2/MCO/PA4(HS)

I2CDATA/PA6(HS)

ATPWM3/PA5(HS)

ATPWM1/PA3(HS)

ei0

ei2

ei1

2 Pin description

Figure 2. 32-pin SDIP package pinout

Figure 3. 32-pin LQFP 7x7 package pinout

17/245

Pin description ST7LITE49K2

Legend / Abbreviations for Tab le 2 :

Type: I = input, O = output, S = supply

In/Output level: C

= CMOS 0.3VDD/0.7VDD with input 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, ana = analog

● Output: OD = open drain, PP = push-pull

The RESET configuration of each pin is shown in bold which is valid as long as the device is in reset state.

Table 2. ST7LITE49K2 device pin description

number

Pin name

SDIP32

LQFP32

1 5 PA 3( H S ) /AT PW M 1 I/ O CTHS x

PA 4( HS ) /

AT PW M2 /M CO

3 7 PA 5 ( H S ) ATP WM 3 I/ O C

PA 6( HS ) /

I2CDATA

5 9 PA7(HS)/I2CCLK I/O C

6 10 RESET x xReset

812 V

913 V

(2)

10 14 OSC1/CLKIN I

11 15 OSC2 O

12 16 V

13 17 V

SSA

DDA

(2)

Level Port/control

Main

Type

I/O C

Input Output

Input

Output

float

int

wpu

ana

(1)

HS x xx

HS x

ei0

function

(after

reset)

Port A3

(HS)

Port A4

(HS)

Port A5

(HS)

Port A6

(HS)

Alternate

function

AT P WM 1

AT PW M2 /M C

AT P WM 3

I2CDATA

ei0

HS x T

Port A7

(HS)

I2CCLK

S Digital Supply Voltage

S Digital Ground Voltage

Resonator oscillator

inverter input or External

clock input

Resonator oscillator

output

S Analog Ground Voltage

S Analog Supply Voltage

18/245

ST7LITE49K2 Pin description

Table 2. ST7LITE49K2 device pin description

number

Pin name

SDIP32

LQFP32

Type

14 18 PB0/AIN0 I/O C

15 19 PB1/AIN1/CLKIN I/O C

16 20 PB2/AIN2 I/O C

17 21 PB3/AIN3/MOSI I/O C

18 22 PB4/AIN4/MISO I/O C

PB5/AIN5/

19 23

EXTCLK_A/

I/O C

COMPOUTB

20 24 PB6/AIN6/SCK I/O C

Level Port/control

Input Output

Input

Output

float

x xxxPort B1

x x x x Port B2 AIN2

x xxxPort B3

x xxxPort B4

int

wpu

ana

x x x Port B0 AIN0

ei1

x xxxPort B5

x xxxPort B6

(1)

function

Main

(after

reset)

Alternate

function

AIN1/

External

clock source

AIN3/SPI

Master

in/Slave out

data

AIN4/SPI

Master

out/Slave in

data

AIN5/Timer A

input clock/

Comparator

output B

AIN6/SPI

serial clock

21 25

22 26

23 27

PB7/AIN7/SS/

OCMP2_A

PC0/AIN8/

ICAP1_A

PC1/AIN9/

ICAP2_A

I/O C

24 28 PC2/ICCDATA I/O C

25 29 PC3/ICCCLK I/O C

AIN7/SPI

slave select

x xxxPort B7

(active low)/

Timer A

Output

Compare 2

AIN8/Timer A

xxxPort C0

Input

Capture 1

ei2

x xxxPort C1

AIN9/Timer A

input capture

x x x Port C2 ICCDATA

x x x x Port C3 ICCCLK

19/245

Pin description ST7LITE49K2

Table 2. ST7LITE49K2 device pin description

number

LQFP32

26 30

27 31

Pin name

SDIP32

PC4/LTIC/

COMPINB-

PC5/COMPINB+/

BREAK2

Type

I/O C

28 32 PC6/COMPINA+ I/O C

29 1

30 2

PC7/BREAK1/

COMPOUTA

PA0 /C O M P IN A-

/OCMP1_A

I/O C

Level Port/control

Input Output

Input

Output

float

int

wpu

ana

ei2

x xxPort C5

ei2

x xxPort C7

ei0

Main

function

(after

(1)

reset)

xxPort C4

xxPort C6

BREAK1/Ana

xxPort A0

Alternate

function

LTIC/Analog

Comparator

External

Reference

Input B

Analog

Comparator

Input B/

External

break 2

Analog

Comparator

Input A

log

Comparator

Output A

Analog

comparator

external

reference

Input A/ Timer A

Output

Compare 1

31 3 PA1(HS)/ATIC I/O C

32 4 PA2(HS)/ATPWM0 I/O C

1. In the open-drain output column, T defines a true open-drain I/O (P-Buffer and protection diode to VDD are not

implemented).0

2. It is mandatory to connect all available V

HS x xx

and V

pins to the supply voltage and all VSS and V

DDA

Por t A1

(HS)

Por t A2

(HS)

SSA

AT P WM 0

pins to ground.

20/245

AT IC

ST7LITE49K2 Register and memory mapping

3 Register and memory mapping

As shown in Figure 4, 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, 384 bytes of RAM, 256 bytes of data EEPROM and 8 Kbytes of Flash program memory. The RAM space includes up to 128 bytes for the stack from 180h to 1FFh.

The highest address bytes contain the user reset and interrupt vectors.

The Flash memory contains two sectors (see ) mapped in the upper part of the ST7 addressing space so the reset and interrupt vectors are located in Sector 0 (FFE0h-FFFFh).

The size of Flash Sector 0 and other device options are configurable by option bytes (refer to Section 14.1 on page 230).

Caution: Memory locations marked as “Reserved” must never be accessed. Accessing a reserved

area can have unpredictable effects on the device.

Table 3. Hardware register map

Address Block Register label Register name Reset status Remarks

(1)

0000h 0001h 0002h

0003h 0004h 0005h

0006h 0007h 0008h

0009h to

000Bh

000Ch 000Dh 000Eh 000Fh

0010h

Por t A

Por t B

Por t C

LITE

TIMER

PA DR

PA DD R

PA OR

PBDR

PBDDR

PBOR

PCDR

PCDDR

PCOR

LTCSR2

LTA RR LTCNTR LTCSR1

LT IC R

Port A Data register

Port A Data Direction register

Port A Option register

Port B Data register

Port B Data Direction register

Port B Option register

Port C Data register

Port C Data Direction register

Port C Option register

Reserved area (3 bytes)

Lite Timer Control/Status register 2

Lite Timer Auto-reload register

Lite Timer Counter register

Lite Timer Control/Status register 1

Lite Timer Input Capture register

00h 00h 00h

00h 00h 08h

0Fh 00h 00h

0x00 0000b

xxh

R/W R/W R/W

R/W R/W

Read Only

R/W

Read Only

21/245

Table 3. Hardware register map

Address Block Register label Register name Reset status Remarks

0011h 0012h 0013h 0014h 0015h 0016h 0017h 0018h

0019h 001Ah 001Bh 001Ch 001Dh 001Eh 001Fh

0020h

0021h

0022h

0023h

0024h

0025h

0026h

0027h

0028h

0029h 002Ah

002Bh Reserved area (1 byte)

AUTO-

RELOAD

TIMER

AT CS R

CNTR1H

CNTR1L

AT R1 H AT R1 L

PWMCR PWM0CSR PWM1CSR PWM2CSR PWM3CSR

DCR0H

DCR0L

DCR1H

DCR1L

DCR2H

DCR2L

DCR3H

DCR3L

ATICRH

AT IC R L

ATCSR2

BREAKCR1

AT R2 H AT R2 L

DTGR

BREAKEN

(1)

(continued)

Timer Control/Status register

Counter register 1 High

Counter register 1 Low

Auto-Reload register 1 High

Auto-Reload register 1 Low

PWM Output Control register PWM 0 Control/Status register PWM 1 Control/Status register PWM 2 Control/Status register PWM 3 Control/Status register

PWM 0 Duty Cycle register High

PWM 0 Duty Cycle register Low

PWM 1 Duty Cycle register High

PWM 1 Duty Cycle register Low

PWM 2 Duty Cycle register High

PWM 2 Duty Cycle register Low

PWM 3 Duty Cycle register High

PWM 3 Duty Cycle register Low

Input Capture register High

Input Capture register Low

Timer Control/Status register 2

Break Control register 1

Auto-Reload register 2 High

Auto-Reload register 2 Low

Dead Time Generation register

Break Enable register

0x00 0000b

00h 00h 00h 00h 00h 00h 00h 00h 00h 00h 00h 00h 00h 00h 00h 00h 00h 00h 00h 03h 00h 00h 00h 00h 03h

R/W Read Only Read Only

R/W

R/W Read Only Read Only

R/W

AUTO-

002Ch

002Dh 002Eh 002Fh

0030h 0031h

0032h Reserved area (1 byte)

0033h WDG WDGCR Watchdog Control register 7Fh R/W

0034h FLASH FCSR Flash Control/Status register 00h R/W

0035h EEPROM EECSR Data EEPROM Control/Status register 00h R/W

0036h 0037h 0038h

0039h Reserved area (1 byte)

003Ah MCC MCCSR Main Clock Control/Status register 00h R/W

RELOAD

TIMER

ITC

ADC

BREAKCR2 Break Control register 2 00h R/W

ISPR0 ISPR1 ISPR2 ISPR3

EICR

ADCCSR ADCDRH ADCDRL

Interrupt Software Priority register 0 Interrupt Software Priority register 1 Interrupt Software Priority register 2 Interrupt Software Priority register 3

External Interrupt Control register

A/D Control Status register

A/D Data register High

A/D Amplifier Control/Data Low Register

FFh FFh FFh FFh 00h

00h xxh 0xh

R/W

R/W Read Only

R/W

22/245

ST7LITE49K2 Register and memory mapping

Table 3. Hardware register map

(1)

(continued)

Address Block Register label Register name Reset status Remarks

003Bh 003Ch

Clock and

RCCR

SICSR

RC oscillator Control register

System integrity control/status register

FFh

011x 0x00b

00h

R/W

Reset

003Dh AVDTHCR

003Eh to

0047h

0048h 0049h

004Ah 004Bh 004Ch 004Dh 004Eh 004Fh

0050h

0051h

AWU

(2)

Clock

Controller

AWUCSR

AWUPR

DMCR DMSR

DMBK1H

DMBK1L

DMBK2H

DMBK2L

DMCR2

CKCNTCSR Clock Controller Status register 09h R/W

Comparator

0052h

Voltage

VREFCR

Reference

AVD threshold selection register / RC

prescaler

Reserved area (10 bytes)

AWU Control/Status register

AWU Preload register

DM Control register

DM Status register DM Breakpoint register 1 High DM Breakpoint register 1 Low DM Breakpoint register 2 High DM Breakpoint register 2 Low

DM Control register 2

Internal Voltage Reference Control

03h R/W

FFh 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

00h R/W

0053h 0054h

0055h 0056h 0057h 0058h

0059h 005Ah 005Bh 005Ch 005Dh 005Eh 005Fh

0060h

0061h

0062h

0063h

0064h

0065h

0066h

0067h

0068h

0069h 006Ah

0070h

0071h

0072h

Comparator

16-bit Timer

I2C

SPI

CMPACR

CMPBCR

TAC R2 TAC R1

TA CS R

TA IC H R 1

TA I CL R 1

TAOCHR1

TAO CL R1

TACHR

TAC LR

TAACHR

TA AC L R

TA IC H R 2

TA I CL R 2

TAOCHR2

TAO CL R2

I2CCR I2CSR1 I2CSR2

I2CCCR I2COAR1 I2COAR2

I2CDR

SPIDR SPICR SPISR

Comparator A & B and Internal

Reference Control Register

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 Output counter high register

Timer A Output 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

C Control register

C Status register 1

I I2C Status register 2

I2C Clock Control register

C Own Address register 1

I I2C Own Address register 2

I2C Data register

SPI Data register

SPI Control register

SPI Status register

00h R/W

00h 00h 00h xxh xxh 80h 00h

FFh FCh FFh FCh

xxh

80h

00h

40h

00h

0xh

00h

xxh

R/W

R/W Read Only Read Only Read Only

R/W

R/W Read Only Read Only Read Only Read Only Read Only Read Only

R/W

Read only Read only

R/W

23/245

0000h

Flash Memory

Interrupt & Reset Vectors

(1)

HW registers

(1)

0080h

007Fh

FFE0h

FFFFh

Reserved

Short Addressing RAM (zero page)

0080h

00FFh

E000h

DFFFh

FFDFh

128 bytes Stack

0100h

017Fh

8 Kbytes

DEE0h

RCCRH1

RCCRL1

01FFh

0200h

RAM

(384 bytes)

0180h

01FFh

DEE1h

DEE2h

RCCRH0

RCCRL0

DEE3h

E000h

(8 Kbytes)

Flash program memory

(4 Kbytes)

Sector 0

FFFFh

(4 Kbytes)

Sector 1

EFFFh F000h

1000h

10FFh

Data EEPROM

(256 bytes)

1100h

Reserved

0FFFh

1. Legend: x=undefined, R/W=read/write.

2. For a description of the Debug Module registers, see ICC protocol reference manual.

Figure 4. ST7LITE49K2 memory map

1. Refer to Ta bl e 3 for information on hardware registers mapping, and to Table 16 for interrupt vectors addresses.

2. Refer to Section 7.1.1: Internal RC oscillator for details on internal RC oscillator calibration.

24/245

ST7LITE49K2 Flash programmable memory

4 Flash programmable memory

4.1 Introduction

The ST7 single voltage extended Flash (XFlash) is a non-volatile memory that can be electrically erased and programmed either on a byte-by-byte basis or up to 32 bytes in parallel.

The XFlash devices can be programmed off-board (plugged in a programming tool) or onboard using In-Circuit Programming or In-Application Programming.

The array matrix organization allows each sector to be erased and reprogrammed without affecting other sectors.

4.2 Main features

● ICP (In-Circuit Programming)

● IAP (In-Application Programming)

● ICT (In-Circuit Testing) for downloading and executing user application test patterns in

RAM

● Sector 0 size configurable by option byte

● Read-out and write protection

4.3 Programming modes

The ST7 can be programmed in three different ways:

● Insertion in a programming tool. In this mode, Flash sectors 0 and 1, option byte row

and data EEPROM (if present) can be programmed or erased.

● In-Circuit Programming. In this mode, Flash sectors 0 and 1, option byte row and data

EEPROM (if present) can be programmed or erased without removing the device from the application board.

● In-Application Programming. In this mode, sector 1 and data EEPROM (if present) can

be programmed or erased without removing the device from the application board and while the application is running.

4.3.1 In-circuit programming (ICP)

ICP uses a protocol called ICC (In-Circuit Communication) which allows an ST7 plugged on a printed circuit board (PCB) to communicate with an external programming device connected via cable. ICP is performed in three steps:

Switch the ST7 to ICC mode (In-Circuit Communications). This is done by driving a specific signal sequence on the ICCCLK/DATA pins while the RESET ST7 enters ICC mode, it fetches a specific Reset vector which points to the ST7 System Memory containing the ICC protocol routine. This routine enables the ST7 to receive bytes from the ICC interface.

● Download ICP Driver code in RAM from the ICCDATA pin

● Execute ICP Driver code in RAM to program the Flash memory

pin is pulled low. When the

25/245

Flash programmable memory ST7LITE49K2

Depending on the ICP Driver code downloaded in RAM, Flash memory programming can be fully customized (number of bytes to program, program locations, or selection of the serial communication interface for downloading).

4.3.2 In-application programming (IAP)

This mode uses an IAP Driver program previously programmed in Sector 0 by the user (in ICP mode).

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.) IAP mode can be used to program any memory areas except Sector 0, which is Write/Erase protected to allow recovery in case errors occur during the programming operation.

4.4 ICC interface

ICP needs a minimum of 4 and up to 6 pins to be connected to the programming tool. These pins are:

● RESET: device reset

● V

● ICCCLK: ICC output serial clock pin

● ICCDATA: ICC input serial data pin

● OSC1: main clock input for external source

● V

Note: 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 be implemented in case another device forces the signal. Refer to the Programming Tool documentation for recommended resistor values.

2 During the ICP session, the programming tool must control the RESET

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 k to isolate the application RESET circuit in this case. When using a classical RC network with R>1 k 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 In “enabled option byte” mode (38-pulse ICC mode), the internal RC oscillator is forced as a

clock source, regardless of the selection in the option byte. In “disabled option byte” mode (35-pulse ICC mode), pin 9 has to be connected to the PB1/CLKIN 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.

: device power supply ground

: application board power supply (optional, see Note 3)

pin. This can lead to

). A schottky diode can be used

or a reset management IC with open drain output and pull-up resistor>1 kΩ, no

Caution: During normal operation the ICCCLK pin must be internally or externally pulled- up (external

pull-up of 10 kΩ mandatory in noisy environment) to avoid entering ICC mode unexpectedly

26/245

ST7LITE49K2 Flash programmable memory

PROGRAMMING TOOL

ICC CONNECTOR

ICCDATA

ICCCLK

RESET

VDD

HE10 CONNECTOR TYPE

APPLICATION POWER SUPPLY

246810

97 5 3

ICC CONNECTOR

APPLICATION BOARD

ICC Cable

(See Note 3)

ST7

PB1/CLKIN

OPTIONAL

See Note 1

See Note 1 and Caution

See Note 2

APPLICATION RESET SOURCE

APPLICATION

I/O

(See Note 4)

during a reset. In the application, even if the pin is configured as output, any reset will put it back in input pull-up.

Figure 5. Typical ICC Interface

27/245

Flash programmable memory ST7LITE49K2

4.5 Memory protection

There are two different types of memory protection: Read-Out Protection and Write/Erase Protection which can be applied individually.

4.5.1 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. Both program and data EEPROM memory are protected.

In Flash devices, this protection is removed by reprogramming the option. In this case, both program and data EEPROM memory are automatically erased and the device can be reprogrammed.

Read-Out Protection selection depends on the device type:

● In Flash devices it is enabled and removed through the FMP_R bit in the option byte.

● In ROM devices it is enabled by mask option specified in the option list.

4.5.2 Flash write/erase protection

Write/Erase Protection, when set, makes it impossible to both overwrite and erase program memory. It does not apply to EEPROM data. Its purpose is to provide advanced security to applications and prevent any change being made to the memory content. Write/Erase Protection is enabled through the FMP_W bit in the option byte.

Caution: Once set, Write/Erase Protection can never be removed. A write-protected Flash

device is no longer reprogrammable.

4.6 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 Description of Flash control/status register (FCSR)

This register controls the XFlash erasing and programming using ICP, IAP or other programming methods.

1st RASS Key: 0101 0110 (56h)

2nd RASS Key: 1010 1110 (AEh)

When an EPB or another programming tool is used (in socket or ICP mode), the RASS keys are sent automatically.

Reset value: 000 0000 (00h)

7 0

00000OPTLATPGM

28/245

Read/write

ST7LITE49K2 Data EEPROM

DATA

MULTIPLEXER

EECSR

HIGH VOLTAGE

PUMP

0 E2LAT00 0 0 0 E2PGM

EEPROM

MEMORY MATRIX

(1 ROW = 32 x 8 BITS)

ADDRESS

DECODER

32 x 8 BITS

DATA LATCHES

ROW

DECODER

DATA BUS

128128

ADDRESS BUS

5 Data EEPROM

5.1 Introduction

The electrically erasable programmable read only memory can be used as a non volatile back-up for storing data. Using the EEPROM requires a basic access protocol described in this chapter.

5.2 Main features

● Up to 32 bytes programmed in the same cycle

● EEPROM mono-voltage (charge pump)

● Chained erase and programming cycles

● Internal control of the global programming cycle duration

● Wait mode management

● Read-Out Protection

Figure 6. EEPROM block diagram

29/245

Data EEPROM ST7LITE49K2

READ MODE

E2LAT=0

E2PGM=0

WRITE MODE

E2LAT=1

E2PGM=0

READ BYTES

IN EEPROM AREA

WRITE UP TO 32 BYTES

IN EEPROM AREA

(with the same 11 MSB of the address)

START PROGRAMMING CYCLE

E2LAT=1

E2PGM=1 (set by software)

E2LAT

CLEARED BY HARDWARE

5.3 Memory access

The Data EEPROM memory read/write access modes are controlled by the E2LAT bit of the EEPROM Control/Status register (EECSR). The flowchart in Figure 7 describes these different memory access modes.

5.3.1 Read operation (E2LAT=0)

The EEPROM can be read as a normal ROM location when the E2LAT bit of the EECSR register is cleared.

On this device, Data EEPROM can also be used to execute machine code. Take care not to write to the Data EEPROM while executing from it. This would result in an unexpected code being executed.

5.3.2 Write operation (E2LAT=1)

To access the write mode, the E2LAT bit has to be set by software (the E2PGM bit remains cleared). When a write access to the EEPROM area occurs, the value is latched inside the 32 data latches according to its address.

When PGM bit is set by the software, all the previous bytes written in the data latches (up to

32) are programmed in the EEPROM cells. The effective high address (row) is determined

by the last EEPROM write sequence. To avoid wrong programming, the user must take care that all the bytes written between two programming sequences have the same high address: only the five Least Significant Bits of the address can change.

At the end of the programming cycle, the PGM and LAT bits are cleared simultaneously.

Note: Care should be taken during the programming cycle. Writing to the same memory location

will over-program the memory (logical AND between the two write access data result) because the data latches are only cleared at the end of the programming cycle and by the falling edge of the E2LAT bit. It is not possible to read the latched data (see Figure 9).

Figure 7. Data EEPROM programming flowchart

30/245

ST7LITE49K2 Data EEPROM

Byte 1 Byte 2 Byte 32

PHASE 1

Programming cycle

Read operation impossible

PHASE 2

Read operation possible

E2LAT bit

E2PGM bit

Writing data latches Waiting E2PGM and E2LAT to fall

Set by USER application

Cleared by hardware

⇓ Row / byte ⇒ 0123 ... 30 31 Physical Address

0 00h...1Fh

1 20h...3Fh

...

N Nx20h...Nx20h+1Fh

ROW

DEFINITION

Figure 8. Data EEPROM write operation

1. If a programming cycle is interrupted (by a reset action), the integrity of the data in memory is not guaranteed.

5.4 Power saving modes

5.4.1 Wait mode

The DATA EEPROM can enter Wait mode on execution of the WFI instruction of the microcontroller or when the microcontroller enters Active-Halt mode.The data EEPROM will immediately enter this mode if there is no programming in progress, otherwise the data EEPROM will finish the cycle and then enter Wait mode.

5.4.2 Active-halt mode

Refer to Wait mode.

5.4.3 Halt mode

The data EEPROM immediately enters Halt mode if the microcontroller executes the Halt instruction. Therefore the EEPROM will stop the function in progress, and data may be corrupted.

5.5 Access error handling

If a read access occurs while E2LAT=1, then the data bus will not be driven.

If a write access occurs while E2LAT=0, then the data on the bus will not be latched.

If a programming cycle is interrupted (by a RESET action), the integrity of the data in memory will not be guaranteed.

31/245

Data EEPROM ST7LITE49K2

LAT

ERASE CYCLE

WRITE CYCLE

PGM

PROG

READ OPERATION NOT POSSIBLE

WRITE OF

DATA LATCHES

READ OPERATION POSSIBLE

Internal Programming

voltage

5.6 Data EEPROM read-out protection

The read-out protection is enabled through an option bit (see Section 14.1: Option bytes). When this option is selected, the programs and data stored in the EEPROM memory are protected against Read-out (including a re-write protection). In Flash devices, when this protection is removed by reprogramming the option byte, the entire Program memory and EEPROM is first automatically erased.

Note: Both Program Memory and data EEPROM are protected using the same option bit.

Figure 9. Data EEPROM programming cycle

5.7 EEPROM control/status register (EECSR)

Address: 0035h

Reset value: 0000 0000 (00h)

7 0

000000E2LATE2PGM

Read/write

Bits 7:2 = Reserved, forced by hardware to 0

0: Read mode 1: Write mode

Bit 1 = E2LAT Latch access transfer bit: this bit is set by software.

It is cleared by hardware at the end of the programming cycle. It can only be cleared by software if the E2PGM bit is cleared

Bit 0 = E2PGM Programming control and status bit

This bit is set by software to begin the programming cycle. At the end of the programming cycle, this bit is cleared by hardware.

0: Programming finished or not yet started 1: Programming cycle is in progress

Note: If the E2PGM bit is cleared during the programming cycle, the memory data is not

guaranteed.

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ST7LITE49K2 Central processing unit

ACCUMULATOR

X INDEX REGISTER

Y INDEX REGISTER

STACK POINTER

CONDITION CODE REGISTER

PROGRAM COUNTER

1C1 1 HI NZ

RESET VALUE = RESET VECTOR @ FFFEh-FFFFh

15 8

PCH

PCL

RESET VALUE = STACK HIGHER ADDRESS

RESET VALUE =

1X11X1XX

RESET VALUE = XXh

X = Undefined Value

6 Central processing unit

6.1 Introduction

This CPU has a full 8-bit architecture and contains six internal registers allowing efficient 8bit data manipulation.

6.2 Main features

● 63 basic instructions

● Fast 8-bit by 8-bit multiply

● 17 main addressing modes

● Two 8-bit index registers

● 16-bit stack pointer

● Low power modes

● Maskable hardware interrupts

● Non-maskable software interrupt

6.3 CPU registers

The six CPU registers shown in Figure 10. They are not present in the memory mapping and are accessed by specific instructions.

Figure 10. CPU registers

33/245

Central processing unit ST7LITE49K2

6.3.1 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.

6.3.2 Index registers (X and Y)

In indexed addressing modes, these 8-bit registers are used to create either effective addresses or 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 (not pushed to and popped from the stack).

6.3.3 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).

6.3.4 Condition code register (CC)

The 8-bit Condition Code register contains the interrupt mask and four flags representative of the result of the instruction just executed. This register can also be handled by the PUSH and POP instructions.

Reset value: 111x 1xxx

7 0

11I1HI0NZC

Read/write

These bits can be individually tested and/or controlled by specific instructions.

Arithmetic management bits

Bit 4 = H Half carry bit

This bit is set by hardware when a carry occurs between bits 3 and 4 of the ALU during an ADD or ADC instruction. 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.

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ST7LITE49K2 Central processing unit

Bit 3 = I Interrupt mask

bit

This bit is set by hardware when entering in interrupt or by software to disable all interrupts except the TRAP software interrupt. This bit is cleared by software.

0: Interrupts are enabled. 1: Interrupts are disabled. This bit is controlled by the RIM, SIM and IRET instructions and is tested by the JRM

and JRNM instructions.

Note: Interrupts requested while I is set are latched and can be processed when I is cleared. By

default an interrupt routine is not interruptible because the I bit is set by hardware at the start of the routine and reset by the IRET instruction at the end of the routine. If the I bit is cleared by software in the interrupt routine, pending interrupts are serviced regardless of the priority level of the current interrupt routine.

Bit 2 = N Negative bit

This bit is set and cleared by hardware. It is representative of the result sign of the last arithmetic, logical or data manipulation. It is a copy of the 7

bit of the result. 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.

Bit 1 = Z Zero bit

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

bit

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

Bits 5,3 = I1, I0 Interrupt bits

The combination of the I1 and I0 bits gives the current interrupt software priority. 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 Section 10.6: Interrupts for more details.

35/245

Central processing unit ST7LITE49K2

Table 4. Interrupt software priority truth table

Interrupt software priority I1 I0

Level 0 (main) 1 0

Level 1 0 1

Level 2 0 0

Level 3 (= interrupt disable) 1 1

6.3.5 Stack pointer (SP)

Reset value: 01FFh

15 8 7 0

0 0 0 0 0 0 0 1 1 SP6 SP5 SP4 SP3 SP2 SP1 SP0

Read/write

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 11).

Since the stack is 128 bytes deep, the 9 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 SP6 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 11.

● 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.

36/245

ST7LITE49K2 Central processing unit

PCH PCL

PCH

PCL

PCH

PCL

PCH

PCH PCL

PCL

PCH

PCH PCL

CALL

Subroutine

Interrupt

Event

PUSH Y POP Y IRET

RET

or RSP

@ 01FFh

@ 0180h

Stack Higher Address = 01FFh Stack Lower Address =

0180h

Figure 11. Stack manipulation example

37/245

Supply, reset and clock management ST7LITE49K2

7 Supply, reset and clock management

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. The main features are the following:

● Clock management

– 8 MHz internal RC oscillator (enabled by option byte) – Auto-wakeup RC oscillator (enabled by option byte) – 1 to 16 MHz or 32 kHz External crystal/ceramic resonator (selected by option byte) – External clock input (enabled by option byte) – For clock ART counter only: PLL32 for multiplying the 8 MHz frequency by 4

(enabled by option byte). The 8 MHz input frequency is mandatory and can be obtained in the following ways:

- from 8-MHz internal RC oscillator

- from 16-MHz external crystal/ceramic resonator (divided internally by two by default)

● Reset Sequence Manager (RSM)

● System Integrity management (SI)

– Main supply Low voltage detection (LVD) with reset generation (enabled by option

byte)

– Auxiliary Voltage detector (AVD) with interrupt capability for monitoring the main

supply (enabled by option byte)

7.1 RC oscillator adjustment

7.1.1 Internal RC oscillator

The device contains an internal RC oscillator with a specific accuracy for a given device, temperature and voltage range (4.5 V - 5.5 V). It must be calibrated to obtain the frequency required in the application. This is done by software writing a 10-bit calibration value in the RCCR (RC Control register) and in the bits 6:5 in the SICSR (SI Control Status register).

Whenever the microcontroller is reset, the RCCR returns to its default value (FFh), i.e. each time the device is reset, the calibration value must be loaded in the RCCR. Predefined calibration values are stored in EEPROM for 3 and 5 V V

Ta bl e 5 ).

Table 5. Predefined RC oscillator calibration values

RCCR Conditions

RCCRH0 V

RCCRL0 DEE1h

RCCRH1 V

RCCRL1 DEE3h

= 5V

TA= 25°C

fRC = 8 MHz

= 3.3 V

= 25°C

= 8 MHz

supply voltages at 25 °C (see

ST7LITE49K2

Address

(1)

DEE0h

DEE2h

(CR[9:2])

(1)

(CR[1:0])

(1)

(CR[9:2])

(1)

(CR[1:0])

38/245

ST7LITE49K2 Supply, reset and clock management

1. The DEE0h, DEE1h, DEE2h and DEE3h addresses are located in a reserved area in non-volatile memory. They are read-only bytes for the application code. This area cannot be erased or programmed by any ICC operations. For compatibility reasons with the SICSR register, CR[1:0] bits are stored in the 5th and 6th position of DEE1 and DEE3 addresses.

In 38-pulse ICC mode, the internal RC oscillator is forced as a clock source, regardless of the selection in the option byte.

Section 13: Electrical characteristics on page 192 for more information on the frequency

and accuracy of the RC oscillator.

To improve clock stability and frequency accuracy, it is recommended to place a decoupling capacitor, typically 100 nF, between the V V

pins as close as possible to the ST7 device.

SSA

and V

pins and also between the V

DDA

and

These bytes are systematically programmed by ST, including on FASTROM devices.

Caution: If the voltage or temperature conditions change in the application, the frequency may need

to be recalibrated. Refer to application note AN1324 for information on how to calibrate the RC frequency using an external reference signal.

7.1.2 Auto-wakeup RC oscillator

The ST7LITE49K2 also contains an Auto-wakeup RC oscillator. This RC oscillator should be enabled to enter Auto-wakeup from halt mode.

The Auto-wakeup (AWU) RC oscillator can also be configured as the startup clock through the CKSEL[1:0] option bits (see Section 14.1: Option bytes on page 230).

This is recommended for applications where very low power consumption is required.

Switching from one startup clock to another can be done in run mode as follows (see

Figure 12):

Case 1 Switching from internal RC to AWU

1. Set the RC/AWU bit in the CKCNTCSR register to enable the AWU RC oscillator

2. The RC_FLAG is cleared and the clock output is at 1.

3. Wait 3 AWU RC cycles till the AWU_FLAG is set

4. The switch to the AWU clock is made at the positive edge of the AWU clock signal

5. Once the switch is made, the internal RC is stopped

Case 2 Switching from AWU RC to internal RC

1. Reset the RC/AWU bit to enable the internal RC oscillator

2. Using a 4-bit counter, wait until 8 internal RC cycles have elapsed. The counter is

running on internal RC clock.

3. Wait till the AWU_FLAG is cleared (1AWU RC cycle) and the RC_FLAG is set (2 RC

cycles)

4. The switch to the internal RC clock is made at the positive edge of the internal RC clock

signal

5. Once the switch is made, the AWU RC is stopped

39/245

Supply, reset and clock management ST7LITE49K2

Internal RC AWU RC

Set RC/AWU

Poll AWU_FLAG until set

Internal RC

Reset RC/AWU

Poll RC_FLAG until set

AWU RC

Note: 1 When the internal RC is not selected, it is stopped so as to save power consumption.

2 When the internal RC is selected, the AWU RC is turned on by hardware when entering

Auto-wakeup from Halt mode.

3 When the external clock is selected, the AWU RC oscillator is always on.

Figure 12. Clock switching

40/245

ST7LITE49K2 Supply, reset and clock management

CR6CR9 CR2CR3CR4CR5CR8 CR7

OSC

MCCSR

SMS

MCO

CPU

TO CPU AND PERIPHERALS

(1ms timebase @ 8 MHz f

OSC

)

/32 DIVIDER

OSC

/32

OSC

LTIMER

LITE TIMER 2 COUNTER

8-BIT

AT TIMER 2

12-BIT

CLKIN

OSC2

CLKIN

Tunable

OscillatorRC

DIVIDER

Option bits

CLKSEL[1:0]

OSC

1-16 MHz

CLKIN

/OSC1

OSC

DIVIDER

OSC/2

CLKIN/2

Option bits

CLKSEL[1:0]

CR1 CR0

or 32 kHz

CKCNTCSR

RC/AWU

Clock controller

CPU

AWU RC OSC

8 MHz

2 MHz 1 MHz

4 MHz

Prescaler

8 MHz (f

)

RC OSC

500 kHz

CK2 CK1 CK0

AVD TH CR

RCCR

SICSR

PLL

8 MHz --> 32 MHz

Figure 13. Clock management block diagram

41/245

Supply, reset and clock management ST7LITE49K2

7.2 Multi-oscillator (MO)

The main clock of the ST7 can be generated by four different source types coming from the multi-oscillator block (1 to 16 MHz):

● An external source

● 5 different configurations for 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

Ta bl e 6 . Refer to the electrical characteristics section for more details.

7.2.1 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.

Note: When the Multi-Oscillator is not used OSCI1 and OSCI2 must be tied to ground, and PB1 is

selected by default as the external clock.

7.2.2 Crystal/ceramic oscillators

In this mode, with a self-controlled gain feature, oscillator of any frequency from 1 to 16 MHz can be placed on OSC1 and OSC2 pins. This family of oscillators has the advantage of producing a very accurate rate on the main clock of the ST7. In this mode of the multioscillator, 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.

7.2.3 Internal RC oscillator

In this mode, the tunable 1% RC oscillator is used as main clock source. The two oscillator pins have to be tied to ground.

The calibration is done through the RCCR[7:0] and SICSR[6:5] registers.

42/245

ST7LITE49K2 Supply, reset and clock management

OSC1 OSC2

EXTERNAL

ST7

SOURCE

OSC1 OSC2

LOAD

CAPACITORS

ST7

OSC1 OSC2

ST7

Table 6. ST7 clock sources

Hardware configuration

External ClockCrystal/Ceramic ResonatorsInternal RC Oscillator

7.3 Reset sequence manager (RSM)

7.3.1 Introduction

The reset sequence manager includes three RESET sources as shown in Figure 15:

● External RESET source pulse

● Internal LVD RESET (Low Voltage Detection)

● Internal WATCHDOG RESET

Note: A reset can also be triggered following the detection of an illegal opcode or prebyte code.

Refer to Section 12.2.1 on page 189 for further details.

These sources act on the RESET

The RESET service routine vector is fixed at addresses FFFEh-FFFFh in the ST7 memory mapping.

The basic RESET sequence consists of 3 phases as shown in Figure 14:

● Active Phase depending on the RESET source

● 256 CPU clock cycle delay (see Tab le 7 )

pin and it is always kept low during the delay phase.

43/245

Supply, reset and clock management ST7LITE49K2

RESET

active phase

Internal reset

256 or 4096 clock cycles

Fetch vector

Caution: When the ST7 is unprogrammed or fully erased, the Flash is blank and the Reset vector is

not programmed. For this reason, it is recommended to keep the RESET

pin in low state

until programming mode is entered, in order to avoid unwanted behavior.

The 256 CPU clock cycle delay allows the oscillator to stabilize and ensures that recovery has taken place from the Reset state. The shorter or longer clock cycle delay is automatically selected depending on the clock source chosen by option byte.

The Reset vector fetch phase duration is 2 clock cycles.

Table 7. CPU clock delay during Reset sequence

Clock source CPU clock cycle delay

Internal RC 8 MHz Oscillator 4096

Internal RC 32 kHz Oscillator 256

External clock (connected to CLKIN/PB1 pin) 4096

External Crystal/Ceramic Oscillator (connected to OSC1/OSC2 pins) 4096

External Crystal/Ceramic 1-16 MHz Oscillator 4096

External Crystal/Ceramic 32 kHz Oscillator 256

Figure 14. Reset sequence phases

44/245

ST7LITE49K2 Supply, reset and clock management

RESET

INTERNAL RESET

PULSE

GENERATOR

Filter

LVD RESET

___

WATCHDOG RESET

___

ILLEGAL OPCODE RESET

___

7.3.2 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 Electrical Characteristic section for more details.

A RESET signal originating from an external source must have a duration of at least t

h(RSTL)in

in order to be recognized (see Figure 16: Reset sequences). This detection is

asynchronous and therefore the MCU can enter reset state even in Halt mode.

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.

Figure 15. Reset block diagram

1. See Section 12.2.1: Illegal opcode reset on page 189 for more details on illegal opcode reset conditions.

7.3.3 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 V the minimum level specified for the selected f

A proper reset signal for a slow rising V RC network connected to the RESET

frequency.

OSC

supply can generally be provided by an external

pin.

is over

7.3.4 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 (rising edge) or V

The LVD filters spikes on V

pin acts as an output that is pulled low when V

lower than V

(falling edge) as shown in Figure 16.

IT-

larger than t

45/245

to avoid parasitic resets.

g(VDD)

is lower than V

IT+

Supply, reset and clock management ST7LITE49K2

w(RSTL)out

RUN RUN

WATCHDOG

RESET

INTERNAL RESET (256 or 4096 T

CPU

)

VECTOR FETCH

ACTIVE PHASE

RUN

RESET PIN

EXTERNAL

WATCHDOG

ACTIVE PHASE

IT+(LVD)

IT-(LVD)

h(RSTL)in

RUN

WATCHDOG UNDERFLOW

RESET

RESET SOURCE

EXTERNAL

RESET

LVD

RESET

ACTIVE

PHASE

7.3.5 Internal watchdog reset

The Reset sequence generated by an internal watchdog counter overflow is shown in

Figure 16: Reset sequences

Starting from the watchdog counter underflow, the device RESET is pulled low during at least t

w(RSTL)out

Figure 16. Reset sequences

pin acts as an output that

46/245

ST7LITE49K2 Supply, reset and clock management

7.4 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.

Note: A reset can also be triggered following the detection of an illegal opcode or prebyte code.

Refer to Section 12.2.1 on page 189 for further details.

7.4.1 Low voltage detector (LVD)

The Low Voltage Detector function (LVD) generates a static reset when the VDD supply voltage is below a V as the power-down keeping the ST7 in reset.

reference value. This means that it secures the power-up as well

IT-(LVD)

The V

reference value for a voltage drop is lower than the V

IT-(LVD)

IT+(LVD)

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 V

● V

IT+(LVD)

IT-(LVD)

when VDD is rising

when VDD is falling

is below:

The LVD function is illustrated in Figure 17.

The voltage threshold can be configured by option byte to be low, medium or high. See

Section 14.1 on page 230.

Provided the minimum V

value (guaranteed for the oscillator frequency) is above V

IT-(LVD)

the MCU can only be in two modes:

● 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.

Note: Use of LVD with capacitive power supply: with this type of power supply, if power cuts occur

in the application, it is recommended to pull V

down to 0 V to ensure optimum restart

conditions. Refer to circuit example in Figure 122 on page 225 and note 4.

The LVD is an optional function which can be selected by option byte. See Section 14.1 on

page 230.

It allows the device to be used without any external RESET circuitry.

If the LVD is disabled, an external circuitry must be used to ensure a proper power-on reset.

It is recommended to make sure that the V

supply voltage rises monotonously when the

device is exiting from Reset, to ensure the application functions properly.

Make sure that the right combination of LVD and AVD thresholds is used as LVD and AVD levels are not correlated. Refer to section Section 13.3.2 on page 195 and Section 13.3.3 on

page 196 for more details.

Caution: If an LVD reset occurs after a watchdog reset has occurred, the LVD will take priority and will

clear the watchdog flag.

47/245

Supply, reset and clock management ST7LITE49K2

IT+(LVD)

RESET

IT-(LVD)

hys

LOW VOLTAGE

DETECTOR

(LVD)

AUXILIARY VOLTAGE

DETECTOR

(AVD)

RESET

RESET SEQUENCE

MANAGER

(RSM)

AVD Interrupt Request

SYSTEM INTEGRITY MANAGEMENT

WATCHDOG

SICSR

TIMER (WDG)

AVDIEAVDF

STATUS FLAG

CR0CR1

LVDRF

0WDGF

Figure 17. Low voltage detector vs reset

Figure 18. Reset and supply management block diagram

7.4.2 Auxiliary voltage detector (AVD)

The Voltage Detector function (AVD) is based on an analog comparison between a V and V

IT+(AVD)

reference value for falling voltage is lower than the V voltage in order to avoid parasitic detection (hysteresis).

The output of the AVD comparator is directly readable by the application software through a real time status bit (AVDF) in the SICSR register. This bit is read only.

Monitoring the VDD main supply

The AVD threshold is selected by the AVD[1:0] bits in the AVDTHCR register.

If the AVD interrupt is enabled, an interrupt is generated when the voltage crosses the V

IT+(AVD)

In the case of a drop in voltage, the AVD interrupt acts as an early warning, allowing

48/245

software to shut down safely before the LVD resets the microcontroller. See Figure 19.

The interrupt on the rising edge is used to inform the application that the V is over.

reference value and the VDD main supply voltage (V

or V

IT-(AVD)

threshold (AVDF bit is set).

IT+(AVD)

). The V

AVD

IT-(AVD)

reference value for rising

warning state

IT-(AVD)

ST7LITE49K2 Supply, reset and clock management

IT+(AVD)

IT-(AVD)

AVDF bit

0 1RESET

IF AVDIE bit = 1

hyst

AVD INTERRUPT REQUEST

INTERRUPT Cleared by

IT+(LVD)

IT-(LVD)

LVD RESET

Early Warning Interrupt

(Power has dropped, MCU not not yet in reset)

hardware

INTERRUPT Cleared by

reset

Note: Make sure that the right combination of LVD and AVD thresholds is used as LVD and AVD

levels are not correlated. Refer to Section 13.3.2 on page 195 and Section 13.3.3 on page

196 for more details.

Figure 19. Using the AVD to monitor V

7.4.3 Low power modes

Table 8. Low power modes

Mode Description

Wait No effect on SI. AVD interrupts cause the device to exit from Wait mode.

Halt

Interrupts

The AVD interrupt event generates an interrupt if the corresponding Enable Control Bit (AVDIE) is set and the interrupt mask in the CC register is reset (RIM instruction).

Table 9. Description of interrupt events

Interrupt event Event flag

AVD event AVDF AVDIE Yes No

The SICSR register is frozen. The AVD remains active but the AVD interrupt cannot be used to exit from Halt mode.

Enable

Control

bit

Exit from

Wait

Exit from

Halt

49/245

Supply, reset and clock management ST7LITE49K2

7.5 Register description

7.5.1 Main clock control/status register (MCCSR)

Reset value: 0000 0000 (00h)

7 0

000000MCOSMS

Read/write

Bits 7:2 = Reserved, must be kept cleared.

Bit 1 = MCO Main Clock Out enable

This bit is read/write by software and cleared by hardware after a reset. This bit allows to enable the MCO output clock.

0: MCO clock disabled, I/O port free for general purpose I/O. 1: MCO clock enabled.

Bit 0 = SMS Slow mode selection

This bit is read/write by software and cleared by hardware after a reset. This bit selects the input clock f

0: Normal mode (f 1: Slow mode (f

or f

OSC

CPU = fOSC

OSC

CPU = fOSC

/32.

/32)

7.5.2 RC control register (RCCR)

Reset value: 1111 1111 (FFh)

7 0

CR9 CR8 CR7 CR6 CR5 CR4 CR3 CR2

Bits 7:0 = CR[9:2] RC Oscillator Frequency Adjustment bits

These bits must be written immediately after reset to adjust the RC oscillator frequencyand to obtain an accuracy of 1%. The application can store the correct value for each voltage range in Flash memory and write it to this register at start-up.

00h = maximum available frequency FFh = lowest available frequency These bits are used with the CR[1:0] bits in the SICSR register. Refer to Chapter 7.5.3.

bit

Read/write

Note: To tune the oscillator, write a series of different values in the register until the correct

frequency is reached. The fastest method is to use a dichotomy starting with 80h.

50/245

ST7LITE49K2 Supply, reset and clock management

7.5.3 System integrity (SI) control/status register (SICSR)

Reset value: 011x 0x00 (xxh)

7 0

0 CR1 CR0 WDGRF 0 LVDRF AVDF AVDIE

Read/write

Bit 7 = Reserved, must be kept cleared

Bits 6:5 = CR[1:0] RC oscillator frequency adjustment bits

These bits, as well as CR[9:2] bits in the RCCR register must be written immediately after reset to adjust the RC oscillator frequency and to obtain an accuracy of 1%. Refer to Section 7.1.1: Internal RC oscillator on page 38.

Bit 4 = 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). The WDGRF and the LVDRF flags areis used to select the reset source (see Table 10: Reset source selection on

page 51).

Table 10. Reset source selection

RESET source LVDRF WDGRF

External RESET

Watchdog 0 1

LV D 1 X

pin 0 0

Bit 3 = Reserved, must be kept cleared

Bit 2 = LVDRF LVD reset flag

This bit indicates that the last Reset was generated by the LVD block. It is set by hardware (LVD reset) and cleared by software (by reading). When the LVD is disabled by option byte, the LVDRF bit value is undefined.

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.

Bit 1 = 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 is set. Refer to Figure 19 and to Section for additional details.

0: V

over AVD threshold

1: V

under AVD threshold

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Supply, reset and clock management ST7LITE49K2

Bit 0 = AVDIE Voltage detector interrupt enable

bit

This bit is set and cleared by software. It enables an interrupt to be generated when the AVDF flag is set. The pending interrupt information is automatically cleared when software enters the AVD interrupt routine.

0: AVD interrupt disabled 1: AVD interrupt enabled

7.5.4 AVD threshold selection register (AVDTHCR)

Reset value: 0000 0011 (003h)

7 0

CK2 CK1 CK0 0 0 0 AVD1 AVD0

Read/write

Bits 7:5 = CK[2:0] internal RC prescaler selection

These bits are set by software and cleared by hardware after a reset. These bits select the prescaler of the internal RC oscillator. See Figure 13: Clock management block

diagram on page 41 and Tab l e 1 1.

If the internal RC is used with a supply operating range below 3.3 V, a division ratio of at least 2 must be enabled in the RC prescaler.

Table 11. Internal RC prescaler selection bits

CK2 CK1 CK0 f

001 f

010 f

011 f

100 f

others f

OSC

RC/2

RC/4

RC/8

RC/16

Bits 4:2 = Reserved, must be cleared.

Bits 1:0 = AVD[1:0] AVD Threshold selection. These bits are used to select the AVD threshold. They are set and cleared by software. They are set by hardware after a reset.

Table 12. AVD threshold selection bits

AVD1 AVD0 Func ti o nality

00 Low

0 1 Medium

1 0 High

11 AVD off

52/245

ST7LITE49K2 Supply, reset and clock management

7.5.5 Clock controller control/status register (CKCNTCSR)

Reset value: 0000 1001 (09h)

7 0

0000AWU_FLAGRC_FLAG0RC/AWU

Read/write

Bits 7:4 = Reserved, must be kept cleared.

Bit 3 = AWU_FLAG AWU selection

bit

This bit is set and cleared by hardware. 0: No switch from AWU to RC requested 1: AWU clock activated and temporization completed

Bit 2 = RC_FLAG RC selection

bit

This bit is set and cleared by hardware. 0: No switch from RC to AWU requested 1: RC clock activated and temporization completed

Bit 1 = Reserved, must be kept cleared.

Bit 0 = RC/AWU RC/AWU selection

bit

0: RC enabled 1: AWU enabled (default value)

Table 13. Clock register mapping and reset values

Address

(Hex.)

003Ah

label

MCCSR

Reset Value

765 4 3 2 1 0

MCO

SMS

003Bh

003Ch

003Dh

0051h

RCCR

Reset Value

SICSR

Reset Value

AVDTHCR

Reset Value

CKCNTCS

Reset Value

CR9

CK2

CR8

CR1

CK1

CR7

CR01WDGRF

CK0

CR6

53/245

CR5

AWU_

FLAG

CR4

LVDRFxAVD F

RC_FLA

CR3

AVD 1

CR2

AVD IE

AVD 0

RC/AWU

Interrupts ST7LITE49K2

8 Interrupts

8.1 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 – 13 interrupt vectors fixed by hardware – 2 non maskable events: RESET, TRAP

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 mapping

(FFE0h to FFFFh) sorted by hardware priority order.

This enhanced interrupt controller guarantees full upward compatibility with the standard (not nested) ST7 interrupt controller.

8.2 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 each interrupt vector (see

Ta bl e 1 4 ). The processing flow is shown in Figure 20.

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.

54/245

ST7LITE49K2 Interrupts

“IRET”

RESTORE PC, X, A, CC

STACK PC, X, A, CC

LOAD I1:0 FROM INTERRUPT SW REG.

FETCH NEXT

RESET

TLI

PENDING

INSTRUCTION

I1:0

FROM STACK

LOAD PC FROM INTERRUPT VECTOR

Interrupt has the same or a

lower software priority

THE INTERRUPT STAYS PENDING

than current one

Interrupt has a higher

software priority

than current one

EXECUTE

INSTRUCTION

INTERRUPT

Table 14. Interrupt software priority levels

Interrupt software priority Level I1 I0

Level 0 (main)

Level 1

Level 2 0

Level 3 (= interrupt disable) 1 1

Figure 20. Interrupt processing flowchart

Low

High

55/245

Interrupts ST7LITE49K2

PENDING

SOFTWARE

Different

INTERRUPTS

Same

HIGHEST HARDWARE

PRIORITY SERVICED

PRIORITY

HIGHEST SOFTWARE

PRIORITY SERVICED

8.2.1 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 21 describes this decision process.

Figure 21. Priority decision process

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.

2 RESET and TRAP can be considered as having the highest software priority in the decision

process.

8.2.2 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 20). 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.

● 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 20.

● 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.

56/245

ST7LITE49K2 Interrupts

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.

● 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 Table 18: ST7LITE49K2 interrupt mapping. 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 (that is, waiting for

being serviced) will therefore be lost if the clear sequence is executed.

8.3 Interrupts and low power modes

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 Table 18: ST7LITE49K2 interrupt mapping). 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 21.

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.

57/245

Interrupts ST7LITE49K2

MAIN

IT5

IT3

IT2

IT0

IT2

MAIN

IT1

HARDWARE PRIORITY

SOFTWARE

3/0

11 / 10

RIM

IT3

IT2

IT5

IT0

IT4

IT1

IT4

PRIORITY LEVEL

USED STACK = 10 BYTES

MAIN

IT2

TLI

MAIN

IT0

IT3

IT2

IT5

IT0

IT4

IT1

HARDWARE PRIORITY

3/0

RIM

IT1

IT4

IT1

IT2

IT3

I1 I0

11 / 10

SOFTWARE PRIORITY LEVEL

USED STACK = 20 BYTES

8.4 Concurrent and nested management

The following Figure 22 and Figure 23 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 23. The interrupt hardware priority is given in this order from the lowest to the highest: MAIN, IT5, IT4, IT3, IT2, IT1, IT0. The software priority is given for each interrupt.

Caution: A stack overflow may occur without notifying the software of the failure.

Figure 22. Concurrent interrupt management

Figure 23. Nested interrupt management

58/245

ST7LITE49K2 Interrupts

8.5 Description of interrupt registers

8.5.1 CPU CC register interrupt bits

Reset value: 111x 1010(xAh)

7 0

11I1HI0NZC

Read/write

Bits 5, 3 = I1, I0 Software interrupt priority

bits

These two bits indicate the current interrupt software priority (see Ta bl e 1 5). 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 Table 17: Dedicated interrupt instruction set).

TRAP and RESET events can interrupt a level 3 program.

Table 15. Setting the interrupt software priority

Interrupt software priority Level I1 I0

Level 0 (main)

Level 1

Level 2 0

Level 3 (= interrupt disable*) 1 1

8.5.2 Interrupt software priority registers (ISPRx)

All ISPRx register bits are read/write except bit 7:4 of ISPR3 which are read only.

Reset value: 1111 1111 (FFh)

Low

High

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

ISPR3 1 1 1 1 1 1 I1_12 I0_12

ISPRx registers contain the interrupt software priority of each interrupt vector. Each interrupt vector (except RESET and TRAP) has corresponding bits in these registers to define its software priority. This correspondence is shown in Ta bl e 1 6 .

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.

59/245

Interrupts ST7LITE49K2

The RESET and TRAP vectors have no software priorities. When one is serviced, the I1 and I0 bits of the CC register are both set.

Level 0 cannot be written (I1_x = 1, I0_x = 0). In this case, the previously stored value is kept (Example: previous = CFh, write = 64h, result = 44h).

Table 16. Interrupt vector vs ISPRx bits

Vector address ISPRx bits

FFFBh-FFFAh I1_0 and I0_0 bits

(1)

FFF9h-FFF8h I1_1 and I0_1 bits

... ...

FFE1h-FFE0h I1_13 and I0_13 bits

1. Bits in the ISPRx registers 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 behavior

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).

Table 17. Dedicated interrupt instruction set

(1)

Instruction New description Function/Example I1 H I0 N Z C

HALT Entering Halt mode 1 0

IRET Interrupt routine return Pop CC, A, X, PC I1 H I0 N Z C

JRM Jump if I1:0 = 11 (level 3) I1:0 = 11

JRNM Jump if I1:0 <> 11 I1:0 <> 11

POP CC Pop CC from the Stack Mem => CC I1 H I0 N Z C

RIM Enable interrupt (level 0 set) Load 10 in I1:0 of CC 1 0

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

1. 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.

60/245

ST7LITE49K2 Interrupts

Table 18. ST7LITE49K2 interrupt mapping

Exit

from

Halt or

AWU FH

(1)

Address

vector

Number

Source

block

Description

label

Priority

order

RESET Reset

yes FFFEh-FFFFh

N/A

TRAP Software interrupt no FFFCh-FFFDh

(2)

0 AWU Auto-wakeup interrupt AWUCSR yes

FFFAh-FFFBh

1 AVD Auxiliary Voltage Detector interrupt SICSR no FFF8h-FFF9h

2 COMPA Comparator A interrupt CMPACR no FFF6h-FFF7h

3 COMPB Comparator B interrupt CMPBCR no FFF4h-FFF5h

4 ei0 External interrupt 0 (Port A)

5 ei1 External interrupt 1 (Port B) FFF0h-FFF1h

N/A yes

Highest

Priority

FFF2h-FFF3h

6 ei2 External interrupt 2 (Port C) FFEEh-FFEFh

(3)

AT T I M E R

AT timer input Capture/Output

Compare interrupt

AT timer overflow 1 interrupt no FFEAh-FFEBh

AT CS R

no FFECh-FFEDh

9 AT timer Overflow 2 interrupt no FFE8h-FFE9h

10 I

C interrupt

11 SPI SPI interrupt SPICSR no FFE4h-FFE5h

I2CSR1/

I2CSR2

no FFE6h-FFE7h

Lowest Priority

12 TIM16 16-bit timer peripheral interrupt TACSR no FFE2h-FFE3h

(3)

1. For an interrupt, all events do not have the same capability to wake up the MCU from Halt, Active-Halt or Auto-wakeup from Halt modes. Refer to the description of interrupt events for more details.

2. This interrupt exits the MCU from Auto-wakeup from Halt mode only.

3. These interrupts exit the MCU from Active-Halt mode only.

LITE TIMER Lite timer RTC/IC/RTC2 interrupt LTCSR2 yes FFE0h-FFE1h

61/245

Interrupts ST7LITE49K2

8.5.3 External interrupt control register (EICR)

Reset value: 0000 0000 (00h)

7 0

0 0 IS21 IS20 IS11 IS10 IS01 IS00

Read/write

Bits 7:6 = Reserved, must be kept cleared.

Bits 5:4 = IS2[1:0] ei2 sensitivity

bits

These bits define the interrupt sensitivity for ei2 (Port C) according to Ta b l e 1 9 .

Bits 3:2 = IS1[1:0] ei1 sensitivity

bits

These bits define the interrupt sensitivity for ei1 (Port B) according to Ta b le 1 9 .

Bits 1:0 = IS0[1:0] ei0 sensitivity

bits

These bits define the interrupt sensitivity for ei0 (Port A) according to Ta b le 1 9 .

Note: 1 These 8 bits can be written only when the I bit in the CC register is set.

2 Changing the sensitivity of a particular external interrupt clears this pending interrupt. This

can be used to clear unwanted pending interrupts. Refer to Section : External interrupt

function.

Table 19. Interrupt sensitivity bits

ISx1 ISx0 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

62/245

ST7LITE49K2 Power saving modes

POWER CONSUMPTION

Wait

Slow

Run

Active Halt

High

Low

Slow Wait

Halt

9 Power saving modes

9.1 Introduction

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 24):

● Slow

● Wait (and Slow-Wait)

● Active-halt

● Auto-wakeup from Halt (AWUFH)

● 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 (f

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.

Figure 24. Power saving mode transitions

OSC

63/245

Power saving modes ST7LITE49K2

SMS

CPU

NORMAL RUN MODE

REQUEST

OSC

/32 f

OSC

9.2 Slow mode

This mode has two targets:

● To reduce power consumption by decreasing the internal clock in the device,

● To adapt the internal clock frequency (f

Slow mode is controlled by the SMS bit in the MCCSR register which enables or disables Slow mode.

In this mode, the oscillator frequency is divided by 32. The CPU and peripherals are clocked at this lower frequency.

Note: Slow-Wait mode is activated when entering Wait mode while the device is already in Slow

mode.

Figure 25. Slow mode clock transition

) to the available supply voltage.

CPU

9.3 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 bit of the CC register is cleared, 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 26 for a description of the Wait mode flowchart.

64/245

ST7LITE49K2 Power saving modes

WFI INSTRUCTION

RESET

INTERRUPT

CPU

OSCILLATOR PERIPHERALS

IBIT

ON ON

OFF

FETCH RESET VECTOR

OR SERVICE INTERRUPT

CPU

OSCILLATOR PERIPHERALS

IBIT

OFF

CPU

OSCILLATOR PERIPHERALS

IBIT

ON ON

256 CPU CLOCK CYCLE

DELAY

Figure 26. Wait mode flowchart

1. Before servicing an interrupt, the CC register is pushed on the stack. The I bit of the CC register is set during the interrupt routine and cleared when the CC register is popped.

9.4 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 ActiveHalt or Halt mode is given by the LTCSR/ATCSR register status as shown in the following table:

Table 20. Enabling/disabling Active-halt and Halt modes

LTCSR TBIE

bit

0xx0

0111

1xxx

x101

ATCSR OVFIE

bit

ATCSRCK1 bit ATCSRCK0 bit Meaning

Active-halt mode disabled00xx

Active-halt mode enabled

65/245

Power saving modes ST7LITE49K2

HALTRUN RUN

256 CPU

CYCLE DELAY

RESET

INTERRUPT

HALT

INSTRUCTION

FETCH

VECTOR

ACTIVE

[Active-halt Enabled]

9.4.1 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 Active-halt mode is enabled.

The MCU can exit Active-Halt mode on reception of a Lite timer/ AT timer interrupt or a Reset.

● When exiting Active-Halt mode by means of a Reset, a 256 CPU cycle delay occurs.

After the start up delay, the CPU resumes operation by fetching the Reset vector which woke it up (see Figure 28).

● When exiting Active-Halt mode by means of an interrupt, the CPU immediately

resumes operation by servicing the interrupt vector which woke it up (see Figure 28).

When entering Active-Halt mode, the I bit in the CC register is cleared to enable interrupts. Therefore, if an interrupt is pending, the MCU wakes up immediately.

In Active-Halt mode, only the main oscillator and the selected timer counter (LT/AT) are running to keep a wakeup 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).

Caution: As soon as Active-Halt is enabled, executing a HALT instruction while the Watchdog is

active does not generate a Reset if the WDGHALT bit is reset. This means that the device cannot spend more than a defined delay in this power saving mode.

Figure 27. Active-halt timing overview

1. This delay occurs only if the MCU exits Active-Halt mode by means of a RESET.

66/245

ST7LITE49K2 Power saving modes

HALT INSTRUCTION

RESET

INTERRUPT

CPU

OSCILLATOR PERIPHERALS

IBIT

OFF

FETCH RESET VECTOR

OR SERVICE INTERRUPT

CPU

OSCILLATOR PERIPHERALS

IBIT

OFF

CPU

OSCILLATOR PERIPHERALS

IBITS

ON ON

256 CPU CLOCK CYCLE

DELAY

(Active-halt enabled)

Figure 28. Active-halt mode flowchart

1. This delay occurs only if the MCU exits Active-Halt mode by means of a RESET.

2. Peripherals clocked with an external clock source can still be active.

3. Only the Lite timer RTC and AT timer interrupts can exit the MCU from Active-Halt mode.

4. Before servicing an interrupt, the CC register is pushed on the stack. The I bit of the CC register is set during the interrupt routine and cleared when the CC register is popped.

9.4.2 Halt mode

The Halt mode is the lowest power consumption mode of the MCU. It is entered by executing the HALT instruction when Active-halt mode is disabled.

The MCU can exit Halt mode on reception of either a specific interrupt (see Ta bl e 1 8 :

ST7LITE49K2 interrupt mapping) or a Reset. When exiting Halt mode by means of a Reset

or an interrupt, the main oscillator is immediately turned on and the 256 CPU cycle delay is used to stabilize it. 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 30).

When entering Halt mode, the I bit in the CC register is forced to 0 to enable interrupts. Therefore, if an interrupt is pending, the MCU wakes immediately.

In Halt mode, the main oscillator is turned off causing all internal processing to be stopped, including the operation of the on-chip peripherals. All peripherals are not clocked except the ones which get their clock supply from another clock generator (such as an external or auxiliary oscillator).

The compatibility of Watchdog operation with Halt mode is configured by the “WDGHALT” option bit of the option byte. The HALT instruction when executed while the Watchdog system is enabled, can generate a Watchdog Reset (see Section 14.1: Option bytes for more details).

67/245

Power saving modes ST7LITE49K2

HALTRUN RUN

256 CPU CYCLE

DELAY

RESET

INTERRUPT

HALT

INSTRUCTION

FETCH

VECTOR

[Active-halt disabled]

HALT INSTRUCTION

RESET

INTERRUPT

CPU

OSCILLATOR PERIPHERALS

IBIT

OFF OFF

OFF

FETCH RESET VECTOR

OR SERVICE INTERRUPT

CPU

OSCILLATOR PERIPHERALS

IBIT

OFF

CPU

OSCILLATOR PERIPHERALS

IBITS

ON ON

256 CPU CLOCK CYCLE

DELAY

WATCHDOG

ENABLE

DISABLE

WDGHALT

WATCHDOG

RESET

(Active-halt disabled)

Figure 29. Halt timing overview

1. A reset pulse of at least 42 µs must be applied when exiting from Halt mode.

Figure 30. Halt mode flowchart

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 18: ST7LITE49K2 interrupt mappingfor more details.

4. Before servicing an interrupt, the CC register is pushed on the stack. The I bit of the CC register is set during the interrupt routine and cleared when the CC register is popped.

5. The CPU clock must be switched to 1 MHz (RC/8) or AWU RC before entering Halt mode.

68/245

ST7LITE49K2 Power saving modes

AWU RC

AWUFH

AWU_RC

AWUFH

(ei0 source)

oscillator

prescaler/1 .. 255

interrupt

/64

divider

to 8-bit timer Input Capture

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 memory. For example, avoid defining a constant in ROM with the value 0x8E.

● As the HALT instruction clears the I bit 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 wakeup event (reset or external interrupt).

9.5 Auto-wakeup from Halt mode

Auto-wakeup from Halt (AWUFH) mode is similar to Halt mode with the addition of a specific internal RC oscillator for wakeup (Auto-wakeup from Halt oscillator) which replaces the main clock which was active before entering Halt mode. Compared to Active-Halt mode, AWUFH has lower power consumption (the main clock is not kept running), but there is no accurate real-time clock available.

It is entered by executing the HALT instruction when the AWUEN bit in the AWUCSR register has been set.

Figure 31. AWUFH mode block diagram

69/245

Power saving modes ST7LITE49K2

AWUFH interrupt

CPU

RUN MODE HALT MODE 256 t

CPU

RUN MODE

AWU_RC

Clear

by software

AWU

As soon as Halt mode is entered, and if the AWUEN bit has been set in the AWUCSR register, the AWU RC oscillator provides a clock signal (f

AWU_RC

). Its frequency is divided by a fixed divider and a programmable prescaler controlled by the AWUPR register. The output of this prescaler provides the delay time. When the delay has elapsed, the following actions are performed:

● the AWUF flag is set by hardware,

● an interrupt wakes-up the MCU from Halt mode,

● the main oscillator is immediately turned on and the 256 CPU cycle delay is used to

stabilize it.

After this start-up delay, the CPU resumes operation by servicing the AWUFH interrupt. The AWU flag and its associated interrupt are cleared by software reading the AWUCSR register.

To compensate for any frequency dispersion of the AWU RC oscillator, it can be calibrated by measuring the clock frequency f

AWU_RC

and then calculating the right prescaler value. Measurement mode is enabled by setting the AWUM bit in the AWUCSR register in Run mode. This connects f f

AWU_RC

to be measured using the main oscillator clock as a reference timebase.

AWU_RC

to the Input Capture of the 8-bit Lite timer, allowing the

Similarities with Halt mode

The following AWUFH mode behavior is the same as normal Halt mode:

● The MCU can exit AWUFH mode by means of any interrupt with exit from Halt

capability or a reset (see Section 9.4: Active-halt and Halt modes).

● When entering AWUFH mode, the I bit in the CC register is forced to 0 to enable

interrupts. Therefore, if an interrupt is pending, the MCU wakes up immediately.

● In AWUFH mode, the main oscillator is turned off causing all internal processing to be

stopped, including the operation of the on-chip peripherals. None of the peripherals are clocked except those which get their clock supply from another clock generator (such as an external or auxiliary oscillator like the AWU oscillator).

● The compatibility of watchdog operation with AWUFH mode is configured by the

WDGHALT option bit in the option byte. Depending on this setting, the HALT instruction when executed while the watchdog system is enabled, can generate a watchdog Reset.

Figure 32. AWUF Halt timing diagram

70/245

ST7LITE49K2 Power saving modes

RESET

INTERRUPT

CPU

MAIN OSC PERIPHERALS

I[1:0] BITS

OFF OFF

OFF

FETCH RESET VECTOR

OR SERVICE INTERRUPT

CPU

MAIN OSC PERIPHERALS

I[1:0] BITS

OFF

CPU

MAIN OSC PERIPHERALS

I[1:0] BITS

ON ON

256 CPU CLOCK

DELAY

WATCHDOG

ENABLE

DISABLE

WDGHALT

WATCHDOG

RESET

CYCLE

AWU RC OSC ON

AWU RC OSC OFF

HALT INSTRUCTION

(Active-Halt disabled)

(AWUCSR.AWUEN=1)

Figure 33. AWUFH mode flowchart

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 an AWUFH interrupt and some specific interrupts can exit the MCU from Halt mode (such as external

interrupt). Refer to Table 18: ST7LITE49K2 interrupt mapping 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.

71/245

Power saving modes ST7LITE49K2

9.5.1 Register description

9.5.2 AWUFH control/status register (AWUCSR)

Reset value: 0000 0000 (00h)

7 0

00000

AWU

AWUM AWUEN

Read/Write

Bits 7:3 = Reserved

Bit 2 = AWU F Auto-wakeup flag

This bit is set by hardware when the AWU module generates an interrupt and cleared by software on reading AWUCSR. Writing to this bit does not change its value.

0: No AWU interrupt occurred 1: AWU interrupt occurred

Bit 1 = AWU M Auto-wakeup measurement

bit

This bit enables the AWU RC oscillator and connects its output to the Input Capture of the 8-bit Lite timer. This allows the timer to be used to measure the AWU RC oscillator dispersion and then compensate this dispersion by providing the right value in the AWUPRE register.

0: Measurement disabled 1: Measurement enabled

Bit 0 = AWUEN Auto-wakeup from Halt enabled

bit

This bit enables the Auto-wakeup from halt feature: once Halt mode is entered, the AWUFH wakes up the microcontroller after a time delay dependent on the AWU prescaler value. It is set and cleared by software.

0: AWUFH (Auto-wakeup from Halt) mode disabled 1: AWUFH (Auto-wakeup from Halt) mode enabled

Note: Whatever the clock source, this bit should be set to enable the AWUFH mode once the

HALT instruction has been executed.

72/245

ST7LITE49K2 Power saving modes

AWU

64 AWUPR×

AWURC

--------------------

× t

RCSTRT

9.5.3 AWUFH prescaler register (AWUPR)

Reset value: 1111 1111 (FFh)

7 0

AWUPR7 AWUPR6 AWUPR5 AWUPR4 AWUPR3 AWUPR2 AWUPR1 AWUPR0

Read/Write

Bits 7:0= AWUPR[7:0] Auto-wakeup prescaler

These 8 bits define the AWUPR Dividing factor (see Tab le 21 ).

Table 21. Configuring the dividing factor

AWUPR[7:0] Dividing factor

00h Forbidden

01h 1

... ...

FEh 254

FFh 255

In AWU mode, the time during which the MCU stays in Halt mode, t equation below. See also Figure 32 on page 70.

The AWUPR prescaler register can be programmed to modify the time during which the MCU stays in Halt mode before waking up automatically.

Note: If 00h is written to AWUPR, the AWUPR remains unchanged.

Table 22. AWU register mapping and reset values

Address

(Hex.)

0048h

0049h

label

AWUCSR

Reset Val ue

AWUPR

Reset Val ue

76543210

00000AWUFAWUMAWUEN

AWUPR71AWUPR61AWUPR51AWUPR41AWUPR31AWUPR21AWUPR11AWUPR0

, is given by the

AWU

73/245

I/O ports ST7LITE49K2

10 I/O ports

10.1 Introduction

The I/O ports allow data transfer. An I/O port can contain up to 8 pins. Each pin can be programmed independently either as a digital input or digital output. In addition, specific pins may have several other functions. These functions can include external interrupt, alternate signal input/output for on-chip peripherals or analog input.

10.2 Functional description

A Data register (DR) and a Data Direction register (DDR) are always associated with each port. The Option register (OR), which allows input/output options, may or may not be implemented. The following description takes into account the OR register. Refer to the Port Configuration table for device specific information.

An I/O pin is programmed using the corresponding bits in the DDR, DR and OR registers: bit x corresponding to pin x of the port.

Figure 34 shows the generic I/O block diagram.

10.2.1 Input modes

Clearing the DDRx bit selects input mode. In this mode, reading its DR bit returns the digital value from that I/O pin.

If an OR bit is available, different input modes can be configured by software: floating or pullup. Refer to I/O Port Implementation section for configuration.

Note: 1 Writing to the DR modifies the latch value but does not change the state of the input pin.

2 Do not use read/modify/write instructions (BSET/BRES) to modify the DR register.

External interrupt function

Depending on the device, setting the ORx bit while in input mode can configure an I/O as an input with interrupt. In this configuration, a signal edge or level input on the I/O generates an interrupt request via the corresponding interrupt vector (eix).

Falling or rising edge sensitivity is programmed independently for each interrupt vector. The External Interrupt Control register (EICR) or the Miscellaneous register controls this sensitivity, depending on the device.

Each external interrupt vector is linked to a dedicated group of I/O port pins (see pinout description and interrupt section). If several I/O interrupt pins on the same interrupt vector are selected simultaneously, they are logically combined. For this reason if one of the interrupt pins is tied low, it may mask the others.

External interrupts are hardware interrupts. Fetching the corresponding interrupt vector automatically clears the request latch. Changing the sensitivity of a particular external interrupt clears this pending interrupt. This can be used to clear unwanted pending interrupts.

74/245

ST7LITE49K2 I/O ports

Spurious interrupts

When enabling/disabling an external interrupt by setting/resetting the related OR register bit, a spurious interrupt is generated if the pin level is low and its edge sensitivity includes falling/rising edge. This is due to the edge detector input which is switched to '1' when the external interrupt is disabled by the OR register.

To avoid this unwanted interrupt, a "safe" edge sensitivity (rising edge for enabling and falling edge for disabling) has to be selected before changing the OR register bit and configuring the appropriate sensitivity again.

Caution: In case a pin level change occurs during these operations (asynchronous signal input), as

interrupts are generated according to the current sensitivity, it is advised to disable all interrupts before and to reenable them after the complete previous sequence in order to avoid an external interrupt occurring on the unwanted edge.

This corresponds to the following steps:

a) Set the interrupt mask with the SIM instruction (in cases where a pin level change

could occur) b) Select rising edge c) Enable the external interrupt through the OR register d) Select the desired sensitivity if different from rising edge e) Reset the interrupt mask with the RIM instruction (in cases where a pin level

change could occur)

2. To disable an external interrupt: a) Set the interrupt mask with the SIM instruction SIM (in cases where a pin level

change could occur) b) Select falling edge c) Disable the external interrupt through the OR register d) Select rising edge e) Reset the interrupt mask with the RIM instruction (in cases where a pin level

change could occur)

10.2.2 Output modes

Setting the DDRx bit selects output mode. Writing to the DR bits applies a digital value to the I/O through the latch. Reading the DR bits returns the previously stored value.

If an OR bit is available, different output modes can be selected by software: push-pull or open-drain. Refer to I/O Port Implementation section for configuration.

Table 23. DR value and output pin status

DR Push-pull Open-drain

Floating

75/245

I/O ports ST7LITE49K2

DDR

DATA BUS

PAD

ALTERNATE ENABLE

ALTERNATE OUTPUT

OR SEL

DDR SEL

DR SEL

PULL-UP CONDITION

P-BUFFER (see table below)

N-BUFFER

PULL-UP (see table below)

ANALOG

INPUT

If implemented

ALTERNATE

INPUT

DIODES (see table below)

FROM OTHER BITS

EXTERNAL

REQUEST (eix)

INTERRUPT

SENSITIVITY SELECTION

CMOS SCHMITT TRIGGER

BIT

From on-chip peripheral

To on-chip peripheral

Note: Refer to the Port Configuration table for device specific information.

Combinational

Logic

10.2.3 Alternate functions

Many ST7s I/Os have one or more alternate functions. These may include output signals from, or input signals to, on-chip peripherals.Ta bl e 2 describes which peripheral signals can be input/output to which ports.

A signal coming from an on-chip peripheral can be output on an I/O. To do this, enable the on-chip peripheral as an output (enable bit in the peripheral’s control register). The peripheral configures the I/O as an output and takes priority over standard I/O programming. The I/O’s state is readable by addressing the corresponding I/O data register.

Configuring an I/O as floating enables alternate function input. It is not recommended to configure an I/O as pull-up as this will increase current consumption. Before using an I/O as an alternate input, configure it without interrupt. Otherwise spurious interrupts can occur.

Configure an I/O as input floating for an on-chip peripheral signal which can be input and output.

Caution: I/Os which can be configured as both an analog and digital alternate function need special

attention. The user must control the peripherals so that the signals do not arrive at the same time on the same pin. If an external clock is used, only the clock alternate function should be employed on that I/O pin and not the other alternate function.

Figure 34. I/O port general block diagram

76/245

ST7LITE49K2 I/O ports

CONDITION

PAD

EXTERNAL INTERRUPT

POLARITY

DATA BUS

INTERRUPT

DR REGISTER ACCESS

FROM

OTHER

PINS

SOURCE (eix)

SELECTION

ALTERNATE INPUT

ANALOG INPUT

To on-chip peripheral

COMBINATIONAL

LOGIC

PAD

DATA BUS

DR REGISTER ACCESS

R/W

PAD

DATA BUS

DR REGISTER ACCESS

R/W

ALTERNATEALTERNATE

ENABLE OUTPUT

BIT From on-chip peripheral

Table 24. I/O port mode options

(1)

Configuration mode Pull-Up P-Buffer

Floating with/without Interrupt Off

Input

Off

Pull-up with Interrupt On

Output

Push-pull

Off

Open Drain (logic level) Off

1. Off means implemented not activated, On means implemented and activated.

Table 25. I/O port configuration

Hardware configuration

(1)

INPUT

Diodes

to V

On On

to V

(2)

OPEN-DRAIN OUTPUT

(2)

PUSH-PULL OUTPUT

1. When the I/O port is in input configuration and the associated alternate function is enabled as an output, reading the DR register will read the alternate function output status.

2. When the I/O port is in output configuration and the associated alternate function is enabled as an input, the alternate function reads the pin status given by the DR register content.

77/245

I/O ports ST7LITE49K2

floating/pull-up

interrupt

INPUT

floating

(reset state)

INPUT

open-drain

OUTPUT

push-pull

OUTPUT

= DDR, OR

10.2.4 Analog alternate function

Configure the I/O as floating input to use an ADC input. The analog multiplexer (controlled by the ADC registers) switches the analog voltage present on the selected pin to the common analog rail, connected to the ADC input.

Analog Recommendations

Do not change the voltage level or loading on any I/O while conversion is in progress. Do not have clocking pins located close to a selected analog pin.

Caution: The analog input voltage level must be within the limits stated in the absolute maximum

ratings.

10.3 I/O port implementation

The hardware implementation on each I/O port depends on the settings in the DDR and OR registers and specific I/O port features such as ADC input or open drain.

Switching these I/O ports from one state to another should be done in a sequence that prevents unwanted side effects. Recommended safe transitions are illustrated in Figure 35. Other transitions are potentially risky and should be avoided, since they may present unwanted side-effects such as spurious interrupt generation.

Figure 35. Interrupt I/O port state transitions

10.4 Unused I/O pins

Unused I/O pins must be connected to fixed voltage levels. Refer to Section 13.9: I/O port

pin characteristics.

10.5 Low power modes

Table 26. Effect of low power modes on I/O ports

Mode Description

Wait

No effect on I/O ports. External interrupts cause the device to exit from Wait

mode.

Halt

78/245

No effect on I/O ports. External interrupts cause the device to exit from Halt

mode.

ST7LITE49K2 I/O ports

10.6 Interrupts

The external interrupt event generates an interrupt if the corresponding configuration is selected with DDR and OR registers and if the I bit in the CC register is cleared (RIM instruction).

Table 27. Description of interrupt events

Interrupt event Event flag

External interrupt on selected

external event

Enable

control bit

DDRx

ORx

See application notes AN1045 software implementation of I software LCD driver

10.7 Device-specific I/O port configuration

The I/O port register configurations are summarized in Section 10.7.1: Standard ports and

Section 10.7.2: Other ports.

10.7.1 Standard ports

Table 28. PA5:0, PB7:0, PC7:4 and PC2:0 pins

Mode DDR OR

floating input 0 0

pull-up interrupt input 0 1

open drain output 1 0

push-pull output 1 1

Exit from

Wait

Exit from

Halt

Ye s Ye s

C bus master, and AN1048 -

10.7.2 Other ports

Table 29. PA7:6 pins

Table 30. PC3 pin

Mode DDR OR

floating input 0 0

interrupt input 0 1

open drain output 1 0

push-pull output 1 1

Mode DDR OR

floating input 0 0

pull-up input 0 1

79/245

I/O ports ST7LITE49K2

Table 30. PC3 pin (continued)

Mode DDR OR

open drain output 1 0

push-pull output 1 1

Table 31. Port configuration

Input Output

Port Pin name

OR = 0 OR = 1 OR = 0 OR = 1

Por t A

PA5:0 floating pull-up interrupt open drain push-pull

PA7:6 floating interrupt true open drain

Port B PB7:0 floating pull-up interrupt open drain push-pull

Por t C

PC7:4,

PC2:0

floating pull-up interrupt open drain push-pull

PC3 floating pull-up open drain push-pull

Table 32. I/O port register mapping and reset values

Address

(Hex.)

0000h

0001h

0002h

0003h

0004h

label

PA DR

Reset Value

PADDR

Reset Value

PA OR

Reset Value

PBDR

Reset Value

PBDDR

Reset Value

76543210

MSB

0000000

MSB

0000000

MSB

0000000

MSB

0000000

MSB

0000000

LSB

0005h

0006h

0007h

0008h

PBOR

Reset Value

PCDR

Reset Value

PCDDR

Reset Value

PCOR

Reset Value

MSB

0000000

MSB

0000000

MSB

0000000

MSB

0000100

80/245

LSB

ST7LITE49K2 On-chip peripherals

RESET

WDGA

7-BIT DOWNCOUNTER

CPU

CLOCK DIVIDER

WATCHDOG CONTROL REGISTER (CR)

÷16000

11 On-chip peripherals

11.1 Watchdog timer (WDG)

11.1.1 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.

11.1.2 Main features

● Programmable free-running downcounter (64 increments of 16000 CPU cycles)

● 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

11.1.3 Functional description

The counter value stored in the CR register (bits T[6:0]), is decremented every 16000 machine cycles, and the length of the timeout period can be programmed by the user in 64 increments.

If the watchdog is activated (the WDGA bit is set) and when the 7-bit timer (bits T[6:0]) rolls over from 40h to 3Fh (T6 becomes cleared), it initiates a reset cycle pulling low the RESET pin for typically 30µs.

Figure 36. Watchdog block diagram

81/245

On-chip peripherals ST7LITE49K2

The application program must write in the CR 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 CR register must be between FFh and C0h (see Table 33: Watchdog timing):

● 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.

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.

Table 33. Watchdog timing

(1)(2)

CPU

= 8 MHz

WDG

counter code

C0h 1 2

FFh 127 128

1. The timing variation shown in Table 33 is due to the unknown status of the prescaler when writing to the CR register.

2. The number of CPU clock cycles applied during the Reset phase (256 or 4096) must be taken into account in addition to these timings.

11.1.4 Hardware watchdog option

If Hardware Watchdog is selected by option byte, the watchdog is always active and the WDGA bit in the CR is not used.

Refer to the option byte description in Section 14 on page 230.

Using Halt mode with the WDG (WDGHALT option)

If Halt mode with Watchdog is enabled by option byte (No watchdog reset on HALT instruction), it is recommended before executing the HALT instruction to refresh the WDG counter, to avoid an unexpected WDG reset immediately after waking up the microcontroller. Same behavior in active-halt mode.

11.1.5 Interrupts

min

[ms]

max [ms]

None.

82/245

ST7LITE49K2 On-chip peripherals

11.1.6 Register description

Control register (WDGCR)

Reset value: 0111 1111 (7Fh)

7 0

WDGA T6 T5 T4 T3 T2 T1 T0

Read/Write

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.

Bits 6:0 = T[6:0] 7-bit timer (MSB to LSB)

These bits contain the decremented value. A reset is produced when it rolls over from 40h to 3Fh (T6 becomes cleared).

Table 34. Watchdog timer register mapping and reset values

Address

(Hex.)

0033h

label

WDGCR

Reset Valu e

76543210

WDGA0T6

83/245

On-chip peripherals ST7LITE49K2

11.2 Dual 12-bit autoreload timer

11.2.1 Introduction

The 12-bit Autoreload timer can be used for general-purpose timing functions. It is based on one or two free-running 12-bit upcounters with an Input Capture register and four PWM output channels. There are 7 external pins:

● Four PWM outputs

● ATIC/LTIC pins for the Input Capture function

● BREAK pins for forcing a break condition on the PWM outputs

11.2.2 Main features

● Single timer or dual timer mode with two 12-bit upcounters (CNTR1/CNTR2) and two

12-bit autoreload registers (ATR1/ATR2)

● Maskable overflow interrupts

● PWM mode

– Generation of four independent PWMx signals – Dead time generation for Half bridge driving mode with programmable dead time – Frequency 2 kHz - 4 MHz (@ 8 MHz f – Programmable duty-cycles – Polarity control – Programmable output modes

● Output Compare mode

● Input Capture mode

– 12-bit Input Capture register (ATICR) – Triggered by rising and falling edges – Maskable IC interrupt – Long range input capture

● Internal/external break control

● Flexible clock control

● One Pulse mode on PWM2/3

● Force update

CPU

)

84/245

ST7LITE49K2 On-chip peripherals

PWM0

PWM1

PWM2

PWM3

Dead Time

Generator

PWM3 Duty Cycle Generator

12-bit Input Capture

PWM2 Duty Cycle Generator

PWM1 Duty Cycle Generator

PWM0 Duty Cycle Generator

12-Bit Autoreload register 1

12-Bit Upcounter 1

Output Compare

CMP Interrupt

OVF1 interrupt

Edge Detection Circuit

OE0

OE1

OE2

OE3

DTE bit

BPEN bit

Break Function

ATIC

Clock

Control

CPU

Lite timer

1 ms from

OFF

32 MHz

PWM0

PWM1

PWM2

PWM3

Dead Time

Generator

PWM3 Duty Cycle Generator

12-bit Input Capture

12-Bit Autoreload register 2

12-Bit Upcounter 2

PWM2 Duty Cycle Generator

PWM1 Duty Cycle Generator

PWM0 Duty Cycle Generator

12-Bit Autoreload register 1

12-Bit Upcounter 1

Output Compare

CMP Interrupt

OVF1 interrupt OVF2 interrupt

Edge Detection Circuit

OE0

OE1

OE2

OE3

ATIC

DTE bit

BPEN bit

Break Function

LTIC

OP_EN bit

Clock

Control

One Pulse

mode

Output Compare

CMP Interrupt

CPU

Lite timer

1 ms from

OFF

32 MHz

Figure 37. Single timer mode (ENCNTR2=0)

Figure 38. Dual timer mode (ENCNTR2=1)

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On-chip peripherals ST7LITE49K2

PWMfCOUNTER

4096 ATR–()⁄=

Resolution 1 4096 ATR–()⁄=

11.2.3 Functional description

PWM mode

This mode allows up to four Pulse Width Modulated signals to be generated on the PWMx output pins.

● PWM frequency

The four PWM signals can have the same frequency (f frequencies. This is selected by the ENCNTR2 bit which enables Single Timer or Dual Timer mode (see Figure 37 and Figure 38). The frequency is controlled by the counter period and the ATR register value. In Dual Timer mode, PWM2 and PWM3 can be generated with a different frequency controlled by CNTR2 and ATR2.

) or can have two different

PWM

Following the above formula, if f

COUNTER

equals 4 MHz, the maximum value of f 2 MHz (ATR register value = 4094), and the minimum value is 1 kHz (ATR register value = 0).

The maximum value of ATR is 4094 because it must be lower than the DC4R value which must be 4095 in this case.

To update the DCRx registers at 32 MHz, the following precautions must be taken: – If the PWM frequency is < 1 MHz and the TRANx bit is set asynchronously, it

should be set twice after a write to the DCRx registers.

– If the PWM frequency is > 1 MHz, the TRANx bit should be set along with

FORCEx bit with the same instruction (use a load instruction and not 2 bset instructions).

● Duty cycle

The duty cycle is selected by programming the DCRx registers. These are preload registers. The DCRx values are transferred in Active duty cycle registers after an overflow event if the corresponding transfer bit (TRANx bit) is set.

The TRAN1 bit controls the PWMx outputs driven by counter 1 and the TRAN2 bit controls the PWMx outputs driven by counter 2.

PWM generation and output compare are done by comparing these active DCRx values with the counter.

The maximum available resolution for the PWMx duty cycle is:

PWM

where ATR is equal to 0. With this maximum resolution, 0% and 100% duty cycle can be obtained by changing the polarity.

At reset, the counter starts counting from 0. When a upcounter overflow occurs (OVF event), the preloaded Duty cycle values are

transferred to the active Duty Cycle registers and the PWMx signals are set to a high level. When the upcounter matches the active DCRx value the PWMx signals are set to a low level. To obtain a signal on a PWMx pin, the contents of the corresponding active DCRx register must be greater than the contents of the ATR register.

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ST7LITE49K2 On-chip peripherals

PWMx

PWMx PIN

counter

overflow

OPx

PWMxCSR register

inverter

DFF

TRANx

ATCSR2 register

DUTY CYCLE

AUTO-RELOAD

PWMx OUTPUT

4095

000

WITH OE=1 AND OPx=0

(ATR)

(DCRx)

WITH OE=1 AND OPx=1

COUNTER

The maximum value of ATR is 4094 because it must be lower than the DCR value which must be 4095 in this case.

● Polarity inversion

The polarity bits can be used to invert any of the four output signals. The inversion is synchronized with the counter overflow if the corresponding transfer bit in the ATCSR2 register is set (reset value). See Figure 39.

Figure 39. PWM polarity inversion

The Data Flip Flop (DFF) applies the polarity inversion when triggered by the counter overflow input.

● Output control

The PWMx output signals can be enabled or disabled using the OEx bits in the PWMCR register.

Figure 40. PWM function

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On-chip peripherals ST7LITE49K2

COUNTER

PWMx OUTPUTtWITH MOD00=1

AND OPx=0

FFDh FFEh FFFh FFDh FFEh FFFh FFDh FFEh

DCRx=000h

DCRx=FFDh

DCRx=FFEh

DCRx=000h

ATR= FFDh

COUNTER

PWMx OUTPUT

WITH MOD00=1

AND OPx=1

Dead time DT 6:0[]Tcounter1×=

Figure 41. PWM signal from 0% to 100% duty cycle

Dead time generation

A dead time can be inserted between PWM0 and PWM1 using the DTGR register. This is required for half-bridge driving where PWM signals must not be overlapped. The nonoverlapping PWM0/PWM1 signals are generated through a programmable dead time by setting the DTE bit.

DTGR[7:0] is buffered inside so as to avoid deforming the current PWM cycle. The DTGR effect will take place only after an overflow.

Note: 1 Dead time is generated only when DTE=1 and DT[6:0]

PWM output signals will be at their reset state.

2 Half Bridge driving is possible only if polarities of PWM0 and PWM1 are not inverted, i.e. if

OP0 and OP1 are not set. If polarity is inverted, overlapping PWM0/PWM1 signals will be generated.

3 Dead Time generation does not work at 1msec timebase.

≠ 0.

If DTE is set and DT[6:0]=0,

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ST7LITE49K2 On-chip peripherals

DCR0+1 ATR1DCR0

Tdt = DT[6:0] x T

counter1

PWM 0

PWM 1

CNTR1

CK_CNTR1

counter1

OVF

PWM 0

PWM 1

if DTE = 0

if DTE = 1

counter = DCR0

counter = DCR1

Figure 42. Dead time generation

In the above example, when the DTE bit is set:

● PWM goes low at DCR0 match and goes high at ATR1+Tdt

● PWM1 goes high at DCR0+Tdt and goes low at ATR match.

With this programmable delay (Tdt), the PWM0 and PWM1 signals which are generated are not overlapped.

Break function

The break function can be used to perform an emergency shutdown of the application being driven by the PWM signals.

The break function is activated by the external BREAKx pins. This can be selected by using the BRxSEL bits in BREAKCRx register. In order to use the break function it must be previously enabled by software setting the BPENx bits in the BREAKCRx registers.

The Break active level can be programmed by the BRxEDGE bits in the BREAKCRx registers. When an active level is detected on the BREAKx pins, the BAx bits are set and the break function is activated. In this case, the PWM signals are forced to BREAK value if respective OEx bit is set in PWMCR register.

Software can set the BAx bits to activate the break function without using the BREAKx pins. The BREN1 and BREN2 bits in the BREAKEN register are used to enable the break activation on the 2 counters respectively. In Dual Timer mode, the break for PWM2 and PWM3 is enabled by the BREN2 bit. In Single Timer mode, the BREN1 bit enables the break for all PWM channels.

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On-chip peripherals ST7LITE49K2

PWM0

PWM1

PWM2

PWM3

PWM0 PWM1

PWM2

PWM3

BREAKCR1 register

BREAK1 pin

(Inverters)

PWM0PWM1PWM2PWM3BP1ENBA1

Level Selection

BR1SEL

ENCNTR2 bit

BREN1 bit

PWM0/1 Break Enable

PWM2/3 Break Enable

OEx

BR1EDGE

Comparator1

BREAKCR2 register

SWBR1SWBR2--BP2ENBA2

BR2SEL

BR2EDGE

BREAK2 pin

Comparator2

Level Selection

BREN2 bit

When a break function is activated (BAx bit =1 and BREN1/BREN2 =1):

● The break pattern (PWM[3:0] bits in the BREAKCR1) is forced directly on the PWMx

output pins if respective OEx is set. (after the inverter).

● The 12-bit PWM counter CNTR1 is put to its reset value, i.e. 00h (if BREN1 = 1).

● The 12-bit PWM counter CNTR2 is put to its reset value,i.e. 00h (if BREN2 = 1).

● ATR1, ATR2, Preload and Active DCRx are put to their reset values.

● Counters stop counting.

When the break function is deactivated after applying the break (BAx bit go from 1 to 0 by software), Timer takes the control of PWM ports.

Figure 43. ST7LITE49K2 block diagram of break function

Output compare mode

To use this function, load a 12-bit value in the Preload DCRxH and DCRxL registers.

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ST7LITE49K2 On-chip peripherals

DCRx

OUTPUT COMPARE CIRCUIT

COUNTER 1

(ATCSR)CMPIE

PRELOAD DUTY CYCLE REG0/1/2/3

ACTIVE DUTY CYCLE REGx

CNTR1

TRAN1 (ATCSR2)

OVF

(ATCSR)

CMPFx (PWMxCSR)

CMP

REQUESTINTERRUPT

When the 12-bit upcounter CNTR1 reaches the value stored in the Active DCRxH and DCRxL registers, the CMPFx bit in the PWMxCSR register is set and an interrupt request is generated if the CMPIE bit is set.

In Single Timer mode the output compare function is performed only on CNTR1. The difference between both the modes is that, in Single Timer mode, CNTR1 can be compared with any of the four DCR registers, and in Dual Timer mode, CNTR1 is compared with DCR0 or DCR1 and CNTR2 is compared with DCR2 or DCR3.

Note: 1 The output compare function is only available for DCRx values other than 0 (reset value).

2 Duty cycle registers are buffered internally. The CPU writes in Preload Duty Cycle registers

and these values are transferred in Active Duty Cycle registers after an overflow event if the corresponding transfer bit (TRANx bit) is set. Output compare is done by comparing these active DCRx values with the counters.

Figure 44. Block diagram of output compare mode (single timer)

Input capture mode

The 12-bit ATICR register is used to latch the value of the 12-bit free running upcounter CNTR1 after a rising or falling edge is detected on the ATIC pin. When an Input Capture occurs, the ICF bit is set and the ATICR register contains the value of the free running upcounter. An IC interrupt is generated if the ICIE bit is set. The ICF bit is reset by reading the ATICRH/ATICRL register when the ICF bit is set. The ATICR is a read only register and always contains the free running upcounter value which corresponds to the most recent Input Capture. Any further Input Capture is inhibited while the ICF bit is set.

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On-chip peripherals ST7LITE49K2

ATCSR

CK0CK1ICIEICF

12-BIT AUTORELOAD REGISTER

12-BIT UPCOUNTER1

CPU

ATIC

12-BIT INPUT CAPTURE REGISTER

IC INTERRUPT

REQUEST

ATR1

ATICR

CNTR1

(1 ms

LTIMER

@ 8MHz)

timebase

OFF

32 MHz

COUNTER1

01h

COUNTER

xxh

02h 03h 04h 05h 06h 07h

04h

ATIC PIN

ICF FLAG

INTERRUPT

08h 09h 0Ah

INTERRUPT

ATICR READ

09h

Figure 45. Block diagram of input capture mode

Figure 46. Input capture timing diagram

Long range input capture

Pulses that last more than 8 µs can be measured with an accuracy of 4 µs if f MHz in the following conditions:

● The 12-bit AT4 timer is clocked by the Lite timer (RTC pulse: CK[1:0] = 01 in the ATCSR

● The ICS bit in the ATCSR2 register is set so that the LTIC pin is used to trigger the AT4

timer capture.

● The signal to be captured is connected to LTIC pin

● Input Capture registers LTICR, ATICRH and ATICRL are read

This configuration allows to cascade the Lite timer and the 12-bit AT4 timer to get a 20-bit input capture value. Refer to Figure 47.

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equals 8

OSC

ST7LITE49K2 On-chip peripherals

LT IC

AT IC

ICS

12-bit Input Capture register

OFF

cpu

LTI M ER

12-bit Upcounter1

12-bit AutoReload register

8-bit Input Capture register

8-bit Timebase Counter1

OSC/32

LTI CR

CNTR1

ATI CR

ATR 1

8 LSB bits

12 MSB bits

LITE TIMER

12-Bit ARTIMER

20 cascaded bits

32 MHz

Figure 47. Long range input capture block diagram

Since the Input Capture flags (ICF) for both timers (AT4 timer and LT timer) are set when signal transition occurs, software must mask one interrupt by clearing the corresponding ICIE bit before setting the ICS bit.

If the ICS bit changes (from 0 to 1 or from 1 to 0), a spurious transition might occur on the Input Capture signal because of different values on LTIC and ATIC. To avoid this situation, it is recommended to do as follows:

1. First, reset both ICIE bits.

2. Then set the ICS bit.

3. Reset both ICF bits.

4. And then set the ICIE bit of desired interrupt.

Computing a pulse length in long Input Capture mode is not straightforward since both timers are used. The following steps are required:

1. At the first Input Capture on the rising edge of the pulse, we assume that values in the registers are the following:

– LTICR = LT1 – ATICRH = ATH1 – ATICRL = ATL1 – Hence ATICR1 [11:0] = ATH1 & ATL1. Refer to Figure 48 on page 94.

2. At the second Input Capture on the falling edge of the pulse, we assume that the values in the registers are as follows:

– LTICR = LT2 – ATICRH = ATH2 – ATICRL = ATL2 – Hence ATICR2 [11:0] = ATH2 & ATL2.

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On-chip peripherals ST7LITE49K2

P decimal F9 LT1– LT2 1++()× 0.004ms×

decimal FFF N×()N ATICR2 ATICR1– 1–++()1ms×+

F9h 00h LT1 F9h 00h LT2

ATH1 & ATL1

00h

LT1

ATH1

LT2

ATH2

OSC/32

TB Counter1

CNTR1

LTIC

LTICR

ATICRH

00h

ATL1

ATL2

ATICRL

ATICR = ATICRH[3:0] & ATICRL[7:0]

_ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _

ATH2 & ATL2

_ _ _

Now pulse width P between first capture and second capture is given by:

where N is the number of overflows of 12-bit CNTR1.

Figure 48. Long range input capture timing diagram

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ST7LITE49K2 On-chip peripherals

One pulse mode

One pulse mode can be used to control PWM2/3 signal with an external LTIC pin. This mode is available only in Dual Timer mode i.e. only for CNTR2, when the OP_EN bit in PWM3CSR register is set.

One Pulse mode is activated by the external LTIC input. The active edge of the LTIC pin is selected by the OPEDGE bit in the PWM3CSR register.

After getting the active edge of the LTIC pin, CNTR2 is reset (000h) and PWM3 is set to high. CNTR2 starts counting from 000h, when it reaches the active DCR3 value then PWM3 goes low. Till this time, any further transitions on the LTIC signal will have no effect. If there are LTIC transitions after CNTR2 reaches DCR3 value, CNTR2 is reset again and PWM3 goes high.

If there is no LTIC active edge, CNTR2 counts until it reaches the ATR2 value, then it is reset again and PWM3 is set to high. The counter again starts counting from 000h, when it reaches the active DCR3 value PWM3 goes low, the counter counts until it reaches ATR2, it resets and PWM3 is set to high and so on.

The same operation applies for PWM2, but in this case the comparison is done on DCR2. OP_EN and OPEDGE bits take effect on the fly and are not synchronized with Counter 2 overflow. The output bit OP2/3 can be used to inverse the polarity of PWM2/3 in one-pulse mode. The update of these bits (OP2/3) is synchronized with the counter 2 overflow, they will be updated if the TRAN2 bit is set.

The time taken from activation of LTIC input and CNTR2 reset is between 2 and 3 t

CNTR2

cycles, that is, from around 62.5 ns to 94 ns (at 32 MHz input frequency).

Lite timer Input Capture interrupt should be disabled while 12-bit ARtimer is in One Pulse mode. This is to avoid spurious interrupts.

The priority of the various conditions for PWM3 is the following: Break > one-pulse mode with active LTIC edge > Forced overflow by s/w > one-pulse mode without active LTIC edge > normal PWM operation.

It is possible to update DCR2/3 and OP2/3 at the counter 2 reset, the update is synchronized with the counter reset. This is managed by the overflow interrupt which is generated if counter is reset either due to ATR match or active pulse at LTIC pin. DCR2/3 and OP2/3 update in one-pulse mode is performed dynamically using a software force update. DCR3 update in this mode is not synchronized with any event. That may lead to a longer next PWM3 cycle duration than expected just after the change.

In One Pulse mode ATR2 value must be greater than DCR2/3 value for PWM2/3. (opposite to normal PWM mode).

If there is an active edge on the LTIC pin after the counter has reset due to an ATR2 match, then the timer again gets reset and appears as modified Duty cycle depending on whether the new DCR value is less than or more than the previous value.

The TRAN2 bit should be set along with the FORCE2 bit with the same instruction after a write to the DCR register.

ATR2 value should be changed after an overflow in one pulse mode to avoid any irregular PWM cycle.

When exiting from one pulse mode, the OP_EN bit in the PWM3CSR register should be reset first and then the ENCNTR2 bit (if counter 2 must be stopped).

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On-chip peripherals ST7LITE49K2

LTIC pin

Edge Selection

OPEDGE

PWM3CSR register

OP_EN

12-bit AutoReload register 2

12-bit Upcounter 2

12-bit Active DCR2/3

Generation

PWM

OP2/3

PWM2/3

OVF

ATR 2

CNTR2

LTI C

PWM2/3

000 DCR2/3

000 DCR2/3 ATR2

000

OVF

ATR2 DCR2/3

OVF

ATR2 DCR2/3

CNTR2

LTI C

PWM2/3

counter2

OP_EN=0

OP_EN=1

Note 1: When OP_EN=0, LTIC edges are not taken into account as the timer runs in PWM mode.

How to enter one pulse mode

The steps required to enter One Pulse mode are the following:

1. Load ATR2H/ATR2L with required value.

2. Load DCR3H/DCR3L for PWM3. ATR2 value must be greater than DCR3.

3. Set OP3 in PWM3CSR if polarity change is required.

4. Select CNTR2 by setting ENCNTR2 bit in ATCSR2.

5. Set TRAN2 bit in ATCSR2 to enable transfer.

6. "Wait for Overflow" by checking the OVF2 flag in ATCSR2.

7. Select counter clock using CK<1:0> bits in ATCSR.

8. Set OP_EN bit in PWM3CSR to enable one-pulse mode.

9. Enable PWM3 by OE3 bit of PWMCR.

The "Wait for Overflow" in step 6 can be replaced by a forced update.

Follow the same procedure for PWM2 with the bits corresponding to PWM2.

Note: When break is applied in one-pulse mode, CNTR2, DCR2/3 & ATR2 registers are reset. So,

these registers have to be initialized again when break is removed.

Figure 49. Block diagram of one pulse mode

Figure 50. One pulse mode and PWM timing diagram

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ST7LITE49K2 On-chip peripherals

CNTR2

LTI C

000

counter2

OP_EN=1

(DCR2/3)

old

(DCR2/3)

new

DCR2/3

FORCE2

TRAN2

FFF

(DCR3)

old

(DCR3)

new

ATR2 000

PWM2/3

extra PWM3 period due to DCR3 update dynamically in one-pulse mode.

000

FFF

ARRx

E04

E03

CNTRx

FORCEx

FORCE2

FORCE1

ATCSR2 register

Figure 51. Dynamic DCR2/3 update in one pulse mode

Force update

In order not to wait for the counterx overflow to load the value into active DCRx registers, a programmable counter which when set, make the counters start with the overflow value, i.e. FFFh. After overflow, the counters start counting from their respective auto reload register values.

overflow is provided. For both counters, a separate bit is provided

These bits are FORCE1 and FORCE2 in the ATCSR2 register. FORCE1 is used to force an overflow on Counter 1 and, FORCE2 is used for Counter 2. These bits are set by software and reset by hardware after the respective counter overflow event has occurred.

This feature can be used at any time. All related features such as PWM generation, Output Compare, Input Capture, One-pulse (refer to Figure 51: Dynamic DCR2/3 update in one

pulse mode) etc. can be used this way.

Figure 52. Force overflow timing diagram

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On-chip peripherals ST7LITE49K2

11.2.4 Low power modes

Table 35. Effect of low power modes on autoreload timer

Mode Description

Wait No effect on AT timer

Halt AT timer halted.

11.2.5 Interrupts

Table 36. Description of interrupt events

Interrupt event

Overflow Event OVF1 OVIE1 Yes No Yes

AT4 IC Event ICF ICIE Yes No No

Overflow Event2 OVF2 OVIE2 Yes No No

Event

flag

Enable

control bit

Exit from

Wait

Exit from

Halt

Exit from

Active-halt

Note: The AT4 IC is connected to an interrupt vector. The OVF event is mapped on a separate

vector (see Interrupts chapter). They generate an interrupt if the enable bit is set in the ATCSR register and the interrupt mask in the CC register is reset (RIM instruction).

11.2.6 Register description

Timer control status register (ATCSR)

Reset value: 0x00 0000 (x0h)

7 0

0 ICF ICIE CK1 CK0 OVF1 OVFIE1 CMPIE

Read / Write

Bit 7 = Reserved

Bit 6 = ICF Input capture flag

This Bit is set by hardware and cleared by software by reading the ATICR register (a read access to ATICRH or ATICRL clears this flag). Writing to this bit does not change the bit value.

0: No input capture 1: An input capture has occurred

Bit 5 = ICIE IC interrupt enable

bit

This bit is set and cleared by software. 0: Input Capture Interrupt Disabled

1: Input Capture Interrupt Enabled

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ST7LITE49K2 On-chip peripherals

Bits 4:3 = CK[1:0] Counter clock selection

bits

These bits are set and cleared by software and cleared by hardware after a reset. they select the clock frequency of the counter.

Table 37. Counter clock selection

Counter clock selection CK1 CK0

OFF 0 0

32 MHz 1 1

(1 ms timebase @ 8 MHz) 0 1

LT IM ER

CPU

Bit 2 = OVF1 Overflow flag

This bit is set by hardware and cleared by software by reading the ATCSR register. It indicates the transition of the Counter1 CNTR1 from FFFh to ATR1 value.

0: No Counter Overflow Occurred 1: Counter Overflow Occurred

Bit 1 = OVFIE1 Overflow Interrupt Enable

bit

This bit is read/write by software and cleared by hardware after a reset. 0: Overflow Interrupt Disabled. 1: Overflow Interrupt Enabled.

Bit 0 = CMPIE Compare Interrupt Enable

bit

This bit is read/write by software and cleared by hardware after a reset. it can be used to mask the interrupt generated when any of the cmpfx bit is set.

0: Output Compare Interrupt Disabled. 1: Output Compare Interrupt Enabled.

Counter register 1 high (CNTR1H)

Reset value: 0000 0000 (00h)

15 8

0000

CNTR1_11CNTR1_

Read only

CNTR1_9 CNTR1_8

Counter register 1 low (CNTR1L)

Reset value: 0000 0000 (00h)

7 0

CNTR1_7 CNTR1_6 CNTR1_5 CNTR1_4 CNTR1_3 CNTR1_2 CNTR1_1 CNTR1_0

Bits 15:12 = Reserved

Read only

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On-chip peripherals ST7LITE49K2

Bits 11:0 = CNTR1[11:0] Counter value

This 12-bit register is read by software and cleared by hardware after a reset. The counter CNTR1 increments continuously as soon as a counter clock is selected. To obtain the 12-bit value, software should read the counter value in two consecutive read operations. As there is no latch, it is recommended to read LSB first. In this case, CNTR1H can be incremented between the two read operations and to have an accurate result when f

timer=fCPU

, special care must be taken when CNTR1L values

close to FFh are read. When a counter overflow occurs, the counter restarts from the value specified in the

ATR 1 r e gi s t e r.

Autoreload register (ATR1H)

Reset value: 0000 0000 (00h)

15 8

0000ATR11ATR10ATR9ATR8

Read/write

Autoreload register (ATR1L)

Reset value: 0000 0000 (00h)

7 0

AT R7 AT R6 AT R 5 AT R 4 AT R 3 AT R 2 AT R1 AT R0

Read/write

Bits 11:0 = ATR1[11:0] Autoreload register 1: This is a 12-bit register which is written by software. The ATR1 register value is automatically loaded into the upcounter CNTR1 when an overflow occurs. The register value is used to set the PWM frequency.

PWM output control register (PWMCR)

Reset value: 0000 0000 (00h)

7 0

0OE30OE20OE10OE0

Read/write

Bits 7:0 = OE[3:0] PWMx output enable bits

These bits are set and cleared by software and cleared by hardware after a reset. 0: PWM mode disabled. PWMx Output Alternate function disabled (I/O pin free for

general purpose I/O) 1: PWM mode enabled

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ST ST7LITE49K2 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

1 Description

Table 1. ST7LITE49K2 device summary

Figure 1. ST7LITE49K2 general block diagram

2 Pin description

Figure 2. 32-pin SDIP package pinout

Figure 3. 32-pin LQFP 7x7 package pinout

Table 2. ST7LITE49K2 device pin description

3 Register and memory mapping

Table 3. Hardware register map

Figure 4. ST7LITE49K2 memory map

4 Flash programmable memory

4.1 Introduction

4.2 Main features

4.3 Programming modes

4.3.1 In-circuit programming (ICP)

4.3.2 In-application programming (IAP)

4.4 ICC interface

Figure 5. Typical ICC Interface

4.5 Memory protection

4.5.1 Read-out protection

4.5.2 Flash write/erase protection

4.6 Related documentation

4.7 Description of Flash control/status register (FCSR)

5 Data EEPROM

5.1 Introduction

5.2 Main features

Figure 6. EEPROM block diagram

5.3 Memory access

5.3.1 Read operation (E2LAT=0)

5.3.2 Write operation (E2LAT=1)

Figure 7. Data EEPROM programming flowchart

Figure 8. Data EEPROM write operation

5.4 Power saving modes

5.4.1 Wait mode

5.4.2 Active-halt mode

5.4.3 Halt mode

5.5 Access error handling

5.6 Data EEPROM read-out protection

Figure 9. Data EEPROM programming cycle

5.7 EEPROM control/status register (EECSR)

6 Central processing unit

6.1 Introduction

6.2 Main features

6.3 CPU registers

Figure 10. CPU registers

6.3.1 Accumulator (A)

6.3.2 Index registers (X and Y)

6.3.3 Program counter (PC)

6.3.4 Condition code register (CC)

Table 4. Interrupt software priority truth table

6.3.5 Stack pointer (SP)

Figure 11. Stack manipulation example

7 Supply, reset and clock management

7.1 RC oscillator adjustment

7.1.1 Internal RC oscillator

Table 5. Predefined RC oscillator calibration values

7.1.2 Auto-wakeup RC oscillator

Figure 12. Clock switching

Figure 13. Clock management block diagram

7.2 Multi-oscillator (MO)

7.2.1 External clock source

7.2.2 Crystal/ceramic oscillators

7.2.3 Internal RC oscillator

Table 6. ST7 clock sources

7.3 Reset sequence manager (RSM)

7.3.1 Introduction

Table 7. CPU clock delay during Reset sequence

Figure 14. Reset sequence phases

7.3.2 Asynchronous external RESET pin

Figure 15. Reset block diagram

7.3.3 External power-on reset

7.3.4 Internal low voltage detector (LVD) reset

7.3.5 Internal watchdog reset

Figure 16. Reset sequences

7.4 System integrity management (SI)

7.4.1 Low voltage detector (LVD)