ST ST7LITE2 User Manual

ST7LITE2

8-BIT MICROCONTROLLER WITH SINGLE VOLTAGE FLASH

MEMORY, DATA EEPROM, ADC, TIMERS, SPI

■ Memories

– 8 Kbytes single voltage Flash Program mem-

ory with read-out protection, In-Circuit Programming and In-Application programming (ICP and IAP). 10K write/erase cycles guaranteed, data retention: 20 years at 55°C.

– 384 bytes RAM

■ Clock, Reset and Supply Management

DIP20

– Enhanced reset system – Enhanced low voltage supervisor (LVD) for

main supply and an auxiliary voltage detector (AVD) with interrupt capability for implementing safe power-down procedures

– Clock sources: Internal 1% RC oscillator,

crystal/ceramic resonator or external clock

– Internal 32-MHz input clock for Auto-reload

timer

– Optional x4 or x8 PLL for 4 or 8 MHz internal

clock

– Five Power Saving Modes: Halt, Active-Halt,

Wait and Slow, Auto Wake Up From Halt

■ I/O Ports

– Up to 15 multifunctional bidirectional I/O lines –7 high sink outputs

■ 4 Timers

– Configurable Watchdog Timer – Two 8-bit Lite Timers with prescaler,

1 realtime base and 1 input capture

– One 12-bit Auto-reload Timer with 4 PWM

outputs, input capture and output compare

■ 1 Communication Interface

– SPI synchronous serial interface

■ Interrupt Management

– 10 interrupt vectors plus TRAP and RESET – 15 external interrupt lines (on 4 vectors)

■ A/D Converter

– 7 input channels – Fixed gain Op-amp – 13-bit resolution for 0 to 430 mV (@ 5V V – 10-bit resolution for 430 mV to 5V (@ 5V V

■ Instruction Set

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

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

■ Development Tools

– Full hardware/software development package – DM (Debug Module)

functions

Device Summary

Features ST7LITE20 ST7LITE25 ST7LITE29

Program memory - bytes 8K RAM (stack) - bytes 384 (128) Data EEPROM - bytes - - 256

Peripherals

Operating Supply 2.4V to 5.5V

CPU Frequency

Operating Temperature -40°C to +85°C Packages SO20 300”, DIP20

Lite Timer with Watchdog,

Autoreload Timer, SPI,

10-bit ADC with Op-Amp

Up to 8Mhz

(w/ ext OSC up to 16MHz)

Lite Timer with Watchdog,

Autoreload Timer with 32-MHz input clock,

SPI, 10-bit ADC with Op-Amp

Up to 8Mhz (w/ ext OSC up to 16MHz

and int 1MHz RC 1% PLLx8/4MHz)

SO20

300”

)

Rev. 4

July 2006 1/133

Table of Contents

1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2 PIN DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

3 REGISTER & MEMORY MAP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

4 FLASH PROGRAM MEMORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

4.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

4.2 MAIN FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

4.3 PROGRAMMING MODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

4.4 ICC INTERFACE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

4.5 MEMORY PROTECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

4.6 RELATED DOCUMENTATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

4.7 REGISTER DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

5 DATA EEPROM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

5.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

5.2 MAIN FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

5.3 MEMORY ACCESS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

5.4 POWER SAVING MODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

5.5 ACCESS ERROR HANDLING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

5.6 DATA EEPROM READ-OUT PROTECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

5.7 REGISTER DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

6 CENTRAL PROCESSING UNIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

6.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

6.2 MAIN FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

6.3 CPU REGISTERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

7 SUPPLY, RESET AND CLOCK MANAGEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

7.1 INTERNAL RC OSCILLATOR ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

7.2 PHASE LOCKED LOOP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

7.3 REGISTER DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

7.4 MULTI-OSCILLATOR (MO) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

7.5 RESET SEQUENCE MANAGER (RSM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

7.6 SYSTEM INTEGRITY MANAGEMENT (SI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

8 INTERRUPTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

8.1 NON MASKABLE SOFTWARE INTERRUPT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

8.2 EXTERNAL INTERRUPTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

8.3 PERIPHERAL INTERRUPTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

9 POWER SAVING MODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

9.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

9.2 SLOW MODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

9.3 WAIT MODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

9.4 HALT MODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

9.5 ACTIVE-HALT MODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

9.6 AUTO WAKE UP FROM HALT MODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

10 I/O PORTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

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10.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

10.2 FUNCTIONAL DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

10.3 I/O PORT IMPLEMENTATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

10.4 UNUSED I/O PINS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

10.5 LOW POWER MODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

10.6 INTERRUPTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

10.7 DEVICE-SPECIFIC I/O PORT CONFIGURATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

11 ON-CHIP PERIPHERALS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

11.1 WATCHDOG TIMER (WDG) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

11.2 12-BIT AUTORELOAD TIMER 2 (AT2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

11.3 LITE TIMER 2 (LT2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

11.4 SERIAL PERIPHERAL INTERFACE (SPI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

11.5 10-BIT A/D CONVERTER (ADC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

12 INSTRUCTION SET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

12.1 ST7 ADDRESSING MODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

12.2 INSTRUCTION GROUPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

13 ELECTRICAL CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

13.1 PARAMETER CONDITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

13.2 ABSOLUTE MAXIMUM RATINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

13.3 OPERATING CONDITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

13.4 SUPPLY CURRENT CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

13.5 CLOCK AND TIMING CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

13.6 MEMORY CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

13.7 EMC CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

13.8 I/O PORT PIN CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

13.9 CONTROL PIN CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

13.10 COMMUNICATION INTERFACE CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . 113

13.11 10-BIT ADC CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

14 PACKAGE CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119

14.1 PACKAGE MECHANICAL DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119

14.2 SOLDERING INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

15 DEVICE CONFIGURATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122

15.1 OPTION BYTES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122

15.2 DEVICE ORDERING INFORMATION AND TRANSFER OF CUSTOMER CODE . . . . 124

15.3 DEVELOPMENT TOOLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

15.4 ST7 APPLICATION NOTES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

16 IMPORTANT NOTES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130

16.1 EXECUTION OF BTJX INSTRUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130

16.2 ADC CONVERSION SPURIOUS RESULTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130

16.3 A/ D CONVERTER ACCURACY FOR FIRST CONVERSION . . . . . . . . . . . . . . . . . . . 130

16.4 NEGATIVE INJECTION IMPACT ON ADC ACCURACY . . . . . . . . . . . . . . . . . . . . . . . 130

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Table of Contents

16.5 CLEARING ACTIVE INTERRUPTS OUTSIDE INTERRUPT ROUTINE . . . . . . . . . . . . 130

16.6 USING PB4 AS EXTERNAL INTERRUPT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130

16.7 TIMEBASE 2 INTERRUPT IN SLOW MODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130

17 REVISION HISTORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131

To obtain the most recent version of this datasheet,

please check at www.st.com>products>technical literature>datasheet

Please also pay special attention to the Section “IMPORTANT NOTES” on page 130.

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133

1 INTRODUCTION

ST7LITE2

The ST7LITE2 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 ST7LITE2 features FLASH memory with byte-by-byte In-Circuit Programming (ICP) and InApplication Programming (IAP) capability.

Under software control, the ST7LITE2 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

Figure 1. General Block Diagram

PLL

8MHz -> 32MHz

Int.

1% RC

CLKIN

OSC1 OSC2

RESET

Ext.

OSC

1MHz

16MHz

1MHz

PLL x 8

or PLL X4

/ 2

Internal CLOCK

LVD

POWER SUPPLY

CONTROL

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.

For easy reference, all parametric data are located in section 13 on page 91.

The devices feature 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.

12-Bit

Auto-Reload

TIMER 2

8-Bit

LITE TIMER 2

PA7:0

(8 bits)

PB6:0

(7 bits)

ADDRESS AND DATA BUS

PORT A

PORT B

ADC

+ OpAmp

SPI

8-BIT CORE

ALU

PROGRAM

MEMORY (8K Bytes)

RAM

(384 Bytes)

Debug Module

DATA EEPROM

(256 Bytes)

WATCHDOG

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ST7LITE2

2 PIN DESCRIPTION

Figure 2. 20-Pin SO Package Pinout

RESET

/AIN0/PB0

SCK/AIN1/PB1 MISO/AIN2/PB2 MOSI/AIN3/PB3

CLKIN/AIN4/PB4

AIN5/PB5 AIN6/PB6

Figure 3. 20-Pin DIP Package Pinout

MISO/AIN2/PB2 MOSI/AIN3/PB3

CLKIN/AIN4/PB4

AIN5/PB5 AIN6/PB6

PA7(HS)

MCO/ICCCLK/BREAK/PA6

ATPWM3/ICCDATA/PA5(HS)

ATPWM2/PA4(HS) ATPWM1/PA3(HS)

V V

8 9

ei3

ei2

ei0

ei1

ei3

ei2

ei1

ei0

OSC1/CLKIN

OSC2

PA0 (HS)/LTIC

PA1 (HS)/ATIC

PA2 (HS)/ATPWM0

PA3 (HS)/ATPWM1

PA4 (HS)/ATPWM2

PA5 (HS)/ATPWM3/ICCDATA

PA6/MCO/ICCCLK/BREAK

PA7(HS)

(HS) 20mA high sink capability eix associated external interrupt vector

SCK/AIN1/PB1

/AIN0/PB0

RESET

OSC1/CLKIN

OSC2

PA0(HS)/LTIC

PA1(HS)/ATIC

PA2(HS)/ATPWM0

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(HS) 20mA high sink capability eix associated external interrupt vector

ST7LITE2

PIN DESCRIPTION (Cont’d)

Legend / Abbreviations for Table 1:

Type: I = input, O = output, S = supply In/Output level: C Output level: HS = 20mA 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 1. Device Pin Description

= CMOS 0.3VDD/0.7VDD with input trigger

Pin No.

Level Port / Control

Pin Name

Type

SO20

DIP20

116V

217V

3 18 RESET

I/O C

4 19 PB0/AIN0/SS

S Ground

S Main power supply

I/O C

5 20 PB1/AIN1/SCK I/O C

6 1 PB2/AIN2/MISO I/O C

7 2 PB3/AIN3/MOSI I/O C

8 3 PB4/AIN4/CLKIN I/O C

9 4 PB5/AIN5 I/O C

10 5 PB6/AIN6 I/O C

11 6 PA7 I/O C

Input Output

Input

Output

float

int

wpu

ana

XXXPort B0

(after reset)

Top priority non maskable interrupt (active low)

ei3

X XXXPort B1

X XXXPort B2

ei2

X XXXPort B4

X XXXPort B5 ADC Analog Input 5

X XXXPort B6 ADC Analog Input 6

XXXPort B3

HS X ei1 X X Port A7

Main

Function

Alternate Function

ADC Analog Input 0 or SPI Slave Select (active low) Caution: No negative current injection allowed on this pin. For details, refer to section

13.2.2 on page 92

ADC Analog Input 1 or SPI Serial Clock Caution: No negative current injection allowed on this pin. For details, refer to section

13.2.2 on page 92

ADC Analog Input 2 or SPI Master In/ Slave Out Data

ADC Analog Input 3 or SPI Master Out / Slave In Data

ADC Analog Input 4 or External clock input

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ST7LITE2

Pin No.

Level Port / Control

Main

SO20

DIP20

Pin Name

Type

Input Output

Input

Output

float

wpu

int

ana

Function

(after reset)

Alternate Function

Main Clock Output or In Circuit Communication Clock or External BREAK

Caution: During normal operation this pin must be pulledup, internally or externally (ex-

12 7

PA6 /MCO/ ICCCLK/BREAK

I/O C

X ei1 XXPort A6

ternal pull-up of 10k mandatory in noisy environment). This is to avoid entering ICC mode unexpectedly during a reset. In the application, even if the pin is configured as output, any reset will put it back in input pull-up

13 8

PA5 /ATPWM3/ ICCDATA

I/O C

14 9 PA4/ATPWM2 I/O C

15 10 PA3/ATPWM1 I/O C

16 11 PA2/ATPWM0 I/O C

17 12 PA1/ATIC I/O C

18 13 PA0/LTIC I/O C

HS X

HS X XXPort A4 Auto-Reload Timer PWM2

HS X

HS X XXPort A2 Auto-Reload Timer PWM0

ei1

XXPort A5

XXPort A3 Auto-Reload Timer PWM1

ei0

HS X XXPort A1

HS X XXPort A0 Lite Timer Input Capture

Auto-Reload Timer PWM3 or In Circuit Communication Data

Auto-Reload Timer Input Capture

19 14 OSC2 O Resonator oscillator inverter output

20 15 OSC1/CLKIN I

Resonator oscillator inverter input or External clock input

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3 REGISTER & MEMORY MAP

ST7LITE2

As shown in Figure 4, the MCU is capable of addressing 64K bytes of memories and I/O registers.

The available memory locations consist of 128 bytes of register locations, 384 bytes of RAM, 256 bytes of data EEPROM and 8 Kbytes of user 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 Fig-

ure 4) mapped in the upper part of the ST7 ad-

Figure 4. Memory Map

0080h

0000h

007Fh 0080h

01FFh

0200h

0FFFh

1000h

10FFh

1100h

HW Registers

(see Table 2)

RAM

(384 Bytes)

Reserved

Data EEPROM

(256 Bytes)

00FFh 0100h

017Fh 0180h

01FFh

dressing space so the reset and interrupt vectors are located in Sector 0 (F000h-FFFFh).

The size of Flash Sector 0 and other device options are configurable by Option byte (refer to sec-

tion 15.1 on page 122).

IMPORTANT: Memory locations marked as “Reserved” must never be accessed. Accessing a reseved area can have unpredictable effects on the device.

Short Addressing RAM (zero page)

16-bit Addressing

RAM

128 Bytes Stack

1000h

1001h

RCCR0

RCCR1

DFFFh

E000h

FFDFh

FFE0h

FFFFh

Reserved

Flash Memory

(8K)

Interrupt & Reset Vectors

(see Table 5)

E000h

FBFFh FC00h

FFFFh

8K FLASH

PROGRAM MEMORY

7 Kbytes

SECTOR 1

1 Kbyte

SECTOR 0

FFDFh

see section 7.1 on page 23

FFDEh

RCCR0

RCCR1

see section 7.1 on page 23

9/133

ST7LITE2

Table 2. Hardware Register Map

Address Block Register Label Register Name Reset Status Remarks

0000h 0001h 0002h

0003h 0004h 0005h

0006h 0007h

0008h 0009h 000Ah 000Bh 000Ch

000Dh 000Eh 000Fh 0010h 0011h 0012h 0013h 0014h 0015h 0016h 0017h 0018h 0019h 001Ah 001Bh 001Ch 001Dh 001Eh 001Fh 0020h 0021h 0022h

Port A

Port B

LITE

TIMER 2

AUTO-

RELOAD

TIMER 2

PADR PADDR PAOR

PBDR PBDDR PBOR

LTCSR2 LTARR LTCNTR LTCSR1 LTICR

ATCSR CNTRH CNTRL ATRH ATRL PWMCR PWM0CSR PWM1CSR PWM2CSR PWM3CSR DCR0H DCR0L DCR1H DCR1L DCR2H DCR2L DCR3H DCR3L ATICRH ATICRL TRANCR BREAKCR

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

Reserved Area (2 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

Timer Control/Status Register Counter Register High Counter Register Low Auto-Reload Register High Auto-Reload Register 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 Transfer Control Register Break Control Register

FFh

00h 40h

FFh

00h 00h

00h 00h 00h

0X00 0000h

00h

0X00 0000h

00h 00h 00h 00h 00h 00h 00h 00h 00h 00h 00h 00h 00h 00h 00h 00h 00h 00h 00h 01h 00h

R/W R/W R/W

R/W R/W

R/W

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

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

0023h to

002Dh

002Eh WDG WDGCR Watchdog Control Register 7Fh R/W

0002Fh FLASH FCSR Flash Control/Status Register 00h R/W

00030h EEPROM EECSR Data EEPROM Control/Status Register 00h R/W

0031h 0032h 0033h

0034h 0035h 0036h

10/133

SPI

ADC

SPIDR SPICR SPICSR

ADCCSR ADCDRH ADCDRL

SPI Data I/O Register SPI Control Register SPI Control Status Register

A/D Control Status Register A/D Data Register High A/D Amplifier Control/Data Low Register

Reserved area (11 bytes)

xxh 0xh

00h

xxh 0xh

R/W R/W R/W

R/W Read Only R/W

ST7LITE2

Address Block Register Label Register Name Reset Status Remarks

0037h ITC EICR External Interrupt Control Register 00h R/W

0038h MCC MCCSR Main Clock Control/Status Register 00h R/W

0039h 003Ah

003Bh Reserved area (1 byte)

003Ch ITC EISR External Interrupt Selection Register 0Ch R/W

003Dh to

0048h

0049h 004Ah

004Bh 004Ch 004Dh 004Eh 004Fh 0050h

0051h to

007Fh

Clock and

Reset

AWU

RCCR SICSR

AWUPR AWUCSR

DMCR DMSR DMBK1H DMBK1L DMBK2H DMBK2L

RC oscillator Control Register System Integrity Control/Status Register

Reserved area (12 bytes)

AWU Prescaler Register AWU Control/Status 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

Reserved area (47 bytes)

FFh

0000 0XX0h

FFh 00h

00h 00h 00h 00h 00h 00h

R/W R/W

R/W R/W R/W R/W R/W R/W

Legend: x=undefined, R/W=read/write Notes:

1. The contents of the I/O port DR registers are readable only in output configuration. In input configuration, the values of the I/O pins are returned instead of the DR register contents.

2. The bits associated with unavailable pins must always keep their reset value.

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

11/133

ST7LITE2

4 FLASH PROGRAM 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 on-board using In-Circuit Programming or In-Application Programming.

The array matrix organisation 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 pin is pulled low. When the 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

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.

12/133

FLASH PROGRAM MEMORY (Cont’d)

ST7LITE2

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 –V

: device reset

: device power supply ground

– ICCCLK: ICC output serial clock pin – ICCDATA: ICC input serial data pin – CLKIN/PB4: main clock input for external

source

: application board power supply (option-

–V

al, see Note 3)

Notes:

1. If the ICCCLK or ICCDATA pins are only used as outputs in the application, no signal isolation is necessary. As soon as the Programming Tool is plugged to the board, even if an ICC session is not in progress, the ICCCLK and ICCDATA pins are not available for the application. If they are used as inputs by the application, isolation such as a serial resistor has to 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

pin. This can lead to conflicts between the programming tool and the application reset circuit if it drives more than 5mA at high level (push pull output or pull-up resistor<1K).

A schottky diode can be used to isolate the application RESET circuit in this case. When using a classical RC network with R>1K or a reset management IC with open drain output and pull-up resistor>1K, no additional components are needed. In all cases the user must ensure that no external reset is generated by the application during the ICC session.

3. The use of Pin 7 of the ICC connector depends on the Programming Tool architecture. This pin must be connected when using most ST Programming Tools (it is used to monitor the application power supply). Please refer to the Programming Tool manual.

4. Pin 9 has to be connected to the CLKIN/PB4 pin of the ST7 when the clock is not available in the application or if the selected clock option is not programmed in the option byte. ST7 devices with multi-oscillator capability need to have OSC1 and OSC2 grounded in this case.

5. With any programming tool, while the ICP option is disabled, the external clock has to be provided on PB4. Caution: During normal operation the ICCCLK pin must be pulled- up, internally or externally (external pull-up of 10k mandatory in noisy environment). This is to avoid entering ICC mode unexpectedly 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

(See Note 3)

APPLICATION POWER SUPPLY

OPTIONAL (See Note 4)

CLKIN/PB4

(See Note 5)

PROGRAMMING TOOL

ICC CONNECTOR

HE10 CONNECTOR TYPE

975 3

RESET

ST7

ICCCLK

ICC Cable

246810

ICCDATA

APPLICATION BOARD

APPLICATION RESET SOURCE

See Note 2

See Note 1 and Caution

APPLICATION

I/O

13/133

ST7LITE2

FLASH PROGRAM MEMORY (Cont’d)

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 E

memory are pro-

tected. In flash devices, this protection is removed by re-

programming the option. In this case, both program and data E

memory are automatically

erased and the device can be reprogrammed. Read-out protection selection depends on the de-

vice 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 E

data. Its purpose is to provide advanced security to applications and prevent any change being made to the memory content.

Warning: Once set, Write/erase protection can never be removed. A write-protected flash device is no longer reprogrammable.

Write/erase protection is enabled through the FMP_W bit in the option byte.

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 Register Description

FLASH CONTROL/STATUS REGISTER (FCSR)

Read/Write Reset Value: 000 0000 (00h) 1st RASS Key: 0101 0110 (56h) 2nd RASS Key: 1010 1110 (AEh)

00000OPTLATPGM

Note: This register is reserved for programming using ICP, IAP or other programming methods. It controls the XFlash programming and erasing operations.

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

14/133

5 DATA EEPROM

ST7LITE2

5.1 INTRODUCTION

The Electrically Erasable Programmable Read Only Memory can be used as a non volatile backup for storing data. Using the EEPROM requires a basic access protocol described in this chapter.

Figure 6. EEPROM Block Diagram

EECSR

ADDRESS DECODER

0 E2LAT00 0 0 0 E2PGM

DECODER

ROW

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

HIGH VOLTAGE

PUMP

EEPROM

MEMORY MATRIX

(1 ROW = 32 x 8 BITS)

ADDRESS BUS

128128

DATA

MULTIPLEXER

DATA BUS

32 x 8 BITS

DATA LATCHES

15/133

ST7LITE2

DATA EEPROM (Cont’d)

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.

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.

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,

Figure 7. Data EEPROM Programming Flowchart

READ MODE

E2LAT=0

E2PGM=0

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. This note is illustrated by the Figure 9.

WRITE MODE

E2LAT=1

E2PGM=0

16/133

READ BYTES

IN EEPROM AREA

CLEARED BY HARDWARE

WRITE UP TO 32 BYTES

(with the same 11 MSB of the address)

IN EEPROM AREA

START PROGRAMMING CYCLE

E2PGM=1 (set by software)

E2LAT=1

E2LAT

DATA EEPROM (Cont’d)

Figure 8. Data E

DEFINITION

PROM Write Operation

⇓ Row / Byte ⇒ 0 1 2 3 ... 30 31 Physical Address

ROW

ST7LITE2

...

00h...1Fh 20h...3Fh

Nx20h...Nx20h+1Fh

E2LAT bit

E2PGM bit

Read operation impossible

Byte 1 Byte 2 Byte 32

PHASE 1

Writing data latches Waiting E2PGM and E2LAT to fall

Set by USER application

Programming cycle

PHASE 2

Read operation possible

Cleared by hardware

Note: If a programming cycle is interrupted (by a reset action), the integrity of the data in memory is not

guaranteed.

17/133

ST7LITE2

DATA EEPROM (Cont’d)

5.4 POWER SAVING MODES

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.

Active-Halt mode

Refer to Wait mode.

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 memory data will not be guaranteed.

5.6 Data EEPROM Read-out Protection

The read-out protection is enabled through an option bit (see section 15.1 on page 122).

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

READ OPERATION NOT POSSIBLE

INTERNAL PROGRAMMING VOLTAGE

ERASE CYCLE WRITE CYCLE

WRITE OF

DATA LATCHES

PROG

READ OPERATION POSSIBLE

LAT

PGM

18/133

DATA EEPROM (Cont’d)

ST7LITE2

5.7 REGISTER DESCRIPTION

Bit 0 = E2PGM Programming control and status This bit is set by software to begin the programming

EEPROM CONTROL/STATUS REGISTER (EECSR)

Read/Write Reset Value: 0000 0000 (00h)

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 guaran-

000000E2LATE2PGM

teed

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

Bit 1 = E2LAT Latch Access Transfer 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. 0: Read mode 1: Write mode

Table 3. DATA EEPROM Register Map and Reset Values

Address

(Hex.)

0030h

Label

EECSR

Reset Value

76543210

000000

E2LAT0E2PGM

19/133

ST7LITE2

6 CENTRAL PROCESSING UNIT

6.1 INTRODUCTION

This CPU has a full 8-bit architecture and contains six internal registers allowing efficient 8-bit 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 6 CPU registers shown in Figure 10 are not present in the memory mapping and are accessed by specific instructions.

Figure 10. CPU Registers

RESET VALUE = XXh

Accumulator (A)

The Accumulator is an 8-bit general purpose register used to hold operands and the results of the arithmetic and logic calculations and to manipulate data.

Index Registers (X and Y)

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).

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).

ACCUMULATOR

X INDEX REGISTER

Y INDEX REGISTER

15 8

RESET VALUE = RESET VECTOR @ FFFEh-FFFFh

RESET VALUE = STACK HIGHER ADDRESS

20/133

PCH

RESET VALUE =

70 1C11HI NZ

1X11X1XX

PCL

PROGRAM COUNTER

CONDITION CODE REGISTER

STACK POINTER

X = Undefined Value

CPU REGISTERS (Cont’d) CONDITION CODE REGISTER (CC)

Read/Write Reset Value: 111x1xxx

111HINZC

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. 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.

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

This bit is set and cleared by hardware. It is repre-

sentative 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

(i.e. the most significant bit is a logic 1).

This bit is accessed by the JRMI and JRPL instrucBit 4 = H Half carry.

tions. This bit is set by hardware when a carry occurs be-

tween 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.

Bit 1 = Z Zero.

This bit is set and cleared by hardware. This bit in-

dicates 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 3 = I Interrupt mask.

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.

Bit 0 = C Carry/borrow.

This bit is set and cleared by hardware and soft-

ware. 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.

By default an interrupt routine is not interruptible

ST7LITE2

21/133

ST7LITE2

CPU REGISTERS (Cont’d) STACK POINTER (SP)

Read/Write Reset Value: 01FFh

15 8

00000001

1 SP6 SP5 SP4 SP3 SP2 SP1 SP0

The Stack Pointer is a 16-bit register which is always pointing to the next free location in the stack. It is then decremented after data has been pushed onto the stack and incremented before data is popped from the stack (see Figure 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, with-

out indicating the stack overflow. The previously

stored information is then overwritten and there-

fore lost. The stack also wraps in case of an under-

flow.

The stack is used to save the return address dur-

ing 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 instruc-

tions. 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 decre-

mented 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 in-

terrupt five locations in the stack area.

Figure 11. Stack Manipulation Example

@ 0180h

@ 01FFh

CALL

Subroutine

PCH PCL

Stack Higher Address = 01FFh Stack Lower Address =

Interrupt

Event

X PCH PCL PCH

PCL

0180h

PUSH Y POP Y IRET

X PCH PCL PCH PCL

PCH PCL

RET

or RSP

22/133

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.

Main features

■ Clock Management

– 1 MHz internal RC oscillator (enabled by op-

tion byte, available on ST7LITE25 and ST7LITE29 devices only)

– 1 to 16 MHz or 32kHz External crystal/ceramic

resonator (selected by option byte) – External Clock Input (enabled by option byte) – PLL for multiplying the frequency by 8 or 4

(enabled by option byte) – For clock ART counter only: PLL32 for multi-

plying the 8 MHz frequency by 4 (enabled by

option byte). The 8 MHz input frequency is

mandatory and can be obtained in the follow-

ing ways:

–1 MHz RC + PLLx8 –16 MHz external clock (internally divided

by 2)

–2 MHz. external clock (internally divided by

2) + PLLx8

–Crystal oscillator with 16 MHz output fre-

quency (internally divided by 2)

■ 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 (en-

abled by option byte)

7.1 INTERNAL RC OSCILLATOR ADJUSTMENT

The device contains an internal RC oscillator with an accuracy of 1% for a given device, temperature and voltage range (4.5V-5.5V). It must be calibrated to obtain the frequency required in the application. This is done by software writing a calibration value in the RCCR (RC Control 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 5V V ages at 25°C, as shown in the following table.

supply volt-

RCCR Conditions

RCCR0

RCCR1

Note: – See “ELECTRICAL CHARACTERISTICS” on

page 91. for more information on the frequency and accuracy of the RC oscillator.

– To improve clock stability and frequency accura-

cy, it is recommended to place a decoupling capacitor, typically 100nF, between the V

pins as close as possible to the ST7 device.

– These two bytes are systematically programmed

by ST, including on FASTROM devices. Consequently, customers intending to use FASTROM service must not use these two bytes.

– RCCR0 and RCCR1 calibration values will be

erased if the read-out protection bit is reset after it has been set. See “Read-out Protection” on page 14.

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.

7.2 PHASE LOCKED LOOP

The PLL can be used to multiply a 1MHz frequency from the RC oscillator or the external clock by 4 or 8 to obtain f bled and the multiplication factor of 4 or 8 is selected by 2 option bits.

– The x4 PLL is intended for operation with V

the 2.4V to 3.3V range

– The x8 PLL is intended for operation with V

the 3.3V to 5.5V range

Refer to Section 15.1 for the option byte description.

If the PLL is disabled and the RC oscillator is enabled, then f

If both the RC oscillator and the PLL are disabled, f

is driven by the external clock.

OSC

=25°C

=1MHz

=25°C

=700KHz

OSC =

ST7LITE29

Address

=5V

=3V

OSC

1000h and FFDEh

1001h and FFDFh

of 4 or 8 MHz. The PLL is ena-

1MHz.

ST7LITE2

ST7LITE25

Address

FFDEh

FFDFh

and

23/133

ST7LITE2

PHASE LOCKED LOOP (Cont’d)

Figure 12. PLL Output Frequency Timing Diagram

LOCKED bit set

4/8 x input

freq.

STAB

LOCK

STARTUP

Output freq.

When the PLL is started, after reset or wakeup from Halt mode or AWUFH mode, it outputs the clock after a delay of t

STARTUP

When the PLL output signal reaches the operating frequency, the LOCKED bit in the SICSCR register is set. Full PLL accuracy (ACC a stabilization time of t

STAB

) is reached after

PLL

(see Figure 12 and

13.3.4 Internal RC Oscillator and PLL)

Refer to section 7.6.4 on page 33 for a description of the LOCKED bit in the SICSR register.

7.3 REGISTER DESCRIPTION

MAIN CLOCK CONTROL/STATUS REGISTER (MCCSR)

Read / Write Reset Value: 0000 0000 (00h)

000000

MCO SMS

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

OSC

or f

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

/32.

OSC

CPU = fOSC

/32)

24/133

RC CONTROL REGISTER (RCCR)

Read / Write Reset Value: 1111 1111 (FFh)

CR70 CR60 CR50 CR40 CR30 CR20 CR10

Bits 7:0 = CR[7:0] RC Oscillator Frequency Ad-

justment Bits

These bits must be written immediately after reset to adjust the RC oscillator frequency and to obtain an accuracy of 1%. The application can store the correct value for each voltage range in EEPROM and write it to this register at start-up. 00h = maximum available frequency FFh = lowest available frequency

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.

Figure 13. Clock Management Block Diagram

ST7LITE2

CLKIN

CLKIN /OSC1

OSC2

OSC,PLLOFF,

OSCRANGE[2:0]

Option bits

CLKIN

OSC

1-16 MHZ or 32kHz

OSC

/32 DIVIDER

CR4CR7 CR0CR1CR2CR3CR6 CR5

Tunable

Oscillator1% RC

CPU

PLL 1MHz -> 8MHz PLL 1MHz -> 4MHz

DIVIDER

OSC

DIVIDER

8-BIT

LITE TIMER 2 COUNTER

/32

OSC

RCCR

8MHz -> 32MHz

CLKIN/2

PLL

12-BIT

AT TIMER 2

RC OSC

PLLx4x8

CLKIN/2

OSC/2

OSC,PLLOFF,

OSCRANGE[2:0]

Option bits

LTIMER

(1ms timebase @ 8 MHz f

CPU

TO CPU AND PERIPHERALS

OSC

)

MCO

SMS

MCCSR

CPU

MCO

25/133

ST7LITE2

7.4 MULTI-OSCILLATOR (MO)

The main clock of the ST7 can be generated by four different source types coming from the multioscillator block (1 to 16MHz or 32kHz):

■ an external source

■ 5 crystal or ceramic resonator oscillators

■ an internal high frequency RC oscillator

Each oscillator is optimized for a given frequency range in terms of consumption and is selectable through the option byte. The associated hardware configurations are shown in Table 4. Refer to the electrical characteristics section for more details.

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, PB4 is selected by default as external clock.

Crystal/Ceramic Oscillators

This family of oscillators has the advantage of producing a very accurate rate on the main clock of the ST7. The selection within a list of 4 oscillators with different frequency ranges has to be done by option byte in order to reduce consumption (refer to section 15.1 on page 122 for more details on the frequency ranges). In this mode of the multi-oscillator, the resonator and the load capacitors have to be placed as close as possible to the oscillator pins in order to minimize output distortion and start-up stabilization time. The loading capacitance values must be adjusted according to the selected oscillator.

These oscillators are not stopped during the RESET phase to avoid losing time in the oscillator start-up phase.

Internal RC Oscillator

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

Table 4. ST7 Clock Sources

Hardware Configuration

ST7

LOAD

CAPACITORS

ST7

External ClockCrystal/Ceramic Resonators

External Clock on PB4

Internal RC Oscillator or

OSC1 OSC2

EXTERNAL

SOURCE

OSC1 OSC2

26/133

7.5 RESET SEQUENCE MANAGER (RSM)

ST7LITE2

7.5.1 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 88 for further details.

These sources act on the RESET

pin and it is al-

ways kept low during the delay phase. The RESET service routine vector is fixed at ad-

dresses FFFEh-FFFFh in the ST7 memory map. The basic RESET sequence consists of 3 phases

as shown in Figure 14:

■ Active Phase depending on the RESET source

■ 256 or 4096 CPU clock cycle delay (see table

below)

■ RESET vector fetch

The 256 or 4096 CPU clock cycle delay allows the oscillator to stabilise and ensures that recovery has taken place from the Reset state. The shorter or longer clock cycle delay is automatically selected depending on the clock source chosen by option byte:

Clock Source

Internal RC Oscillator 256 External clock (connected to CLKIN pin) 256 External Crystal/Ceramic Oscillator

(connected to OSC1/OSC2 pins)

CPU clock

cycle delay

4096

The RESET vector fetch phase duration is 2 clock cycles.

If the PLL is enabled by option byte, it outputs the clock after an additional delay of t

STARTUP

(see

Figure 12).

Figure 14. RESET Sequence Phases

RESET

Active Phase

INTERNAL RESET

256 or 4096 CLOCK CYCLES

7.5.2 Asynchronous External RESET

The RESET output with integrated R

pin is both an input and an open-drain

weak pull-up resistor.

FETCH

VECTOR

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). This detection is asynchronous and therefore the MCU can enter reset state even in HALT mode.

Figure 15. Reset Block Diagram

RESET

Note 1: See “Illegal Opcode Reset” on page 88. for more details on illegal opcode reset conditions.

Filter

PULSE

GENERATOR

WATCHDOG RESET ILLEGAL OPCODE RESET

LVD RESET

INTERNAL RESET

27/133

ST7LITE2

RESET SEQUENCE MANAGER (Cont’d)

The RESET plays a major role in EMS performance. In a noisy environment, it is recommended to follow the guidelines mentioned in the electrical characteristics section.

7.5.3 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 level specified for the selected f

A proper reset signal for a slow rising V can generally be provided by an external RC network connected to the RESET

Figure 16. RESET Sequences

pin is an asynchronous signal which

is over the minimum

frequency.

OSC

supply

pin.

7.5.4 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 pulled low when V V

DD<VIT-

(falling edge) as shown in Figure 16.

The LVD filters spikes on V

pin acts as an output that is

DD<VIT+

(rising edge) or

larger than t

g(VDD)

avoid parasitic resets.

7.5.5 Internal Watchdog RESET

The RESET sequence generated by a internal Watchdog counter overflow is shown in Figure 16.

Starting from the Watchdog counter underflow, the device RESET low during at least t

pin acts as an output that is pulled

w(RSTL)out

IT+(LVD)

IT-(LVD)

EXTERNAL RESET SOURCE

RESET PIN

WATCHDOG RESET

RUN

LVD

RESET

ACTIVE PHASE

RUN

h(RSTL)in

EXTERNAL

RESET

ACTIVE PHASE

WATCHDOG UNDERFLOW

RUN RUN

INTERNAL RESET (256 or 4096 T VECTOR FETCH

WATCHDOG

RESET

ACTIVE

PHASE

w(RSTL)out

CPU

)

28/133

7.6 SYSTEM INTEGRITY MANAGEMENT (SI)

ST7LITE2

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 88 for further details.

7.6.1 Low Voltage Detector (LVD)

The Low Voltage Detector function (LVD) generates a static reset when the V below a V

IT-(LVD)

reference value. This means that

supply voltage is

it secures the power-up as well as the power-down keeping the ST7 in reset.

The V

IT-(LVD)

lower than the V

reference value for a voltage drop is

IT+(LVD)

reference value for poweron 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

is below:

–V –V

IT+(LVD)

IT-(LVD)

when VDD is rising

when VDD is falling The LVD function is illustrated in Figure 17. The voltage threshold can be configured by option

byte to be low, medium or high.

Provided the minimum V the oscillator frequency) is above V

value (guaranteed for

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.

Notes: The LVD allows the device to be used without any

external RESET circuitry. The LVD is an optional function which can be se-

lected by option byte. 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

0V to ensure optimum restart conditions. Refer to circuit example in Figure 84 on page 112 and note

4. 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.

Figure 17. Low Voltage Detector vs Reset

IT+

(LVD)

IT-

(LVD)

RESET

hys

29/133

ST7LITE2

Figure 18. Reset and Supply Management Block Diagram

RESET

RESET SEQUENCE

MANAGER

(RSM)

WATCHDOG

TIMER (WDG)

STATUS FLAG

SYSTEM INTEGRITY MANAGEMENT

SICSR

00 LVDRFLOCKEDWDGRF0

LOW VOLTAGE

AUXILIARY VOLTAGE

AVD Interrupt Request

AVDIEAVDF

DETECTOR

(LVD)

DETECTOR

(AVD)

30/133

SYSTEM INTEGRITY MANAGEMENT (Cont’d)

7.6.2 Auxiliary Voltage Detector (AVD)

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

IT+(AVD)

ply voltage (V

reference value and the VDD main sup-

AVD

). The V

IT-(AVD)

reference value

for falling voltage is lower than the V

IT-(AVD)

IT+(AVD)

and

reference value for rising voltage in order to avoid parasitic detection (hysteresis).

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

Caution: The AVD functions only if the LVD is en-

ST7LITE2

abled through the option byte.

7.6.2.1 Monitoring the V

The AVD voltage threshold value is relative to the selected LVD threshold configured by option byte (see section 15.1 on page 122).

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

IT-(AVD)

threshold (AVDF bit is set).

In the case of a drop in voltage, the AVD interrupt acts as an early warning, allowing software to shut down safely before the LVD resets the microcontroller. See Figure 19.

Main Supply

IT+(LVD)

Figure 19. Using the AVD to Monitor V

IT+(AVD)

IT-(AVD)

IT+(LVD)

IT-(LVD)

AVDF bit

AVD INTERRUPT REQUEST

IF AVDIE bit = 1

LVD RESET

INTERRUPT Cleared by

Early Warning Interrupt

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

hyst

RESET

reset

INTERRUPT Cleared by

hardware

31/133

ST7LITE2

SYSTEM INTEGRITY MANAGEMENT (Cont’d)

7.6.3 Low Power Modes

Mode Description

WAIT

HALT

7.6.3.1 Interrupts

The AVD interrupt event generates an interrupt if the corresponding Enable Control Bit (AVDIE) is

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

The SICSR register is frozen. The AVD remains active.

set and the interrupt mask in the CC register is reset (RIM instruction).

Flag

Enable

Control

Bit

Interrupt Event

AVD event AVDF AVDIE Yes No

Event

Exit

from

Wait

Exit

from

Halt

32/133

SYSTEM INTEGRITY MANAGEMENT (Cont’d)

7.6.4 Register Description SYSTEM INTEGRITY (SI) CONTROL/STATUS REGISTER (SICSR)

Read/Write Reset Value: 0000 0xx0 (0xh)

000

WDG

LOCKED LVDRF AVDF AVDIE

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.

Bit 1 = AVDF Voltage Detector flag

Bit 7:5 = Reserved, must be kept cleared.

This read-only bit is set and cleared by hardware. If the AVDIE bit is set, an interrupt request is gen-

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

erated when the AVDF bit is set. Refer to Figure

19 and to Section 7.6.2.1 for additional details.

over AVD threshold

0: V

under AVD threshold

1: V

(writing zero) or an LVD Reset (to ensure a stable cleared state of the WDGRF flag when CPU starts). Combined with the LVDRF flag information, the flag description is given by the following table.

RESET Sources LVDRF WDGRF

External RESET

Watchdog 0 1

LVD 1 X

pin 0 0

Bit 0 = AVDIE Voltage Detector interrupt enable 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

ST7LITE2

Bit 3 = LOCKED PLL Locked Flag This bit is set and cleared by hardware. It is set automatically when the PLL reaches its operating frequency. 0: PLL not locked 1: PLL locked

Application notes

The LVDRF flag is not cleared when another RESET type occurs (external or watchdog), the LVDRF flag remains set to keep trace of the original failure. In this case, a watchdog reset can be detected by software while an external reset can not.

33/133

ST7LITE2

8 INTERRUPTS

The ST7 core may be interrupted by one of two different methods: maskable hardware interrupts as listed in the Interrupt Mapping Table and a nonmaskable software interrupt (TRAP). The Interrupt processing flowchart is shown in Figure 20. The maskable interrupts must be enabled by clearing the I bit in order to be serviced. However, disabled interrupts may be latched and processed when they are enabled (see external interrupts subsection).

Note: After reset, all interrupts are disabled. When an interrupt 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.

– The I bit of the CC register is set to prevent addi-

tional interrupts.

– 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 the Interrupt Mapping Table for vector addresses).

The interrupt service routine should finish 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 I bit will be cleared and the main program will resume.

Priority Management

By default, a servicing interrupt cannot be interrupted because the I bit is set by hardware entering in interrupt routine.

In the case when several interrupts are simultaneously pending, an hardware priority defines which one will be serviced first (see the Interrupt Mapping Table).

Interrupts and Low Power Mode

All interrupts allow the processor to leave the WAIT low power mode. Only external and specifically mentioned interrupts allow the processor to leave the HALT low power mode (refer to the “Exit from HALT“ column in the Interrupt Mapping Table).

8.1 NON MASKABLE SOFTWARE INTERRUPT

This interrupt is entered when the TRAP instruction is executed regardless of the state of the I bit. It will be serviced according to the flowchart on

Figure 20.

8.2 EXTERNAL INTERRUPTS

External interrupt vectors can be loaded into the PC register if the corresponding external interrupt occurred and if the I bit is cleared. These interrupts allow the processor to leave the Halt low power mode.

The external interrupt polarity is selected through the miscellaneous register or interrupt register (if available).

An external interrupt triggered on edge will be latched and the interrupt request automatically cleared upon entering the interrupt service routine.

Caution: The type of sensitivity defined in the Miscellaneous or Interrupt register (if available) applies to the ei source. In case of a NANDed source (as described on the I/O ports section), a low level on an I/O pin configured as input with interrupt, masks the interrupt request even in case of risingedge sensitivity.

8.3 PERIPHERAL INTERRUPTS

Different peripheral interrupt flags in the status register are able to cause an interrupt when they are active if both:

– The I bit of the CC register is cleared. – The corresponding enable bit is set in the control

If any of these two conditions is false, the interrupt is latched and thus remains pending.

Clearing an interrupt request is done by: – Writing “0” to the corresponding bit in the status

– Access to the status register while the flag is set

followed by a read or write of an associated register.

Note: the clearing sequence resets the internal latch. A pending interrupt (i.e. waiting for being enabled) will therefore be lost if the clear sequence is executed.

34/133

INTERRUPTS (Cont’d)

Figure 20. Interrupt Processing Flowchart

FROM RESET

ST7LITE2

INTERRUPT

PENDING?

STACK PC, X, A, CC

SET I BIT

LOAD PC FROM INTERRUPT VECTOR

EXECUTE INSTRUCTION

RESTORE PC, X, A, CC FROM STACK

I BIT SET?

FETCH NEXT INSTRUCTION

THIS CLEARS I BIT BY DEFAULT

IRET?

Table 5. Interrupt Mapping

Exit

N°

Source

Block

Description

Label

Priority

Order

from

HALT or

AWUFH

RESET Reset

TRAP Software Interrupt no

N/A

Highest

Priority

yes yes FFFEh-FFFFh

0 AWU Auto Wake Up Interrupt AWUCSR yes 1 ei0 External Interrupt 0 2 ei1 External Interrupt 1 FFF6h-FFF7h 3 ei2 External Interrupt 2 FFF4h-FFF5h

N/A

yes

4 ei3 External Interrupt 3 FFF2h-FFF3h 5 LITE TIMER LITE TIMER RTC2 interrupt LTCSR2 no FFF0h-FFF1h 6 Not used FFEEh-FFEFh 7 SI AVD interrupt SICSR

AT TIMER

AT TIMER Output Compare Interrupt or Input Capture Interrupt

9 AT TIMER Overflow Interrupt ATCSR yes FFE8h-FFE9h

LITE TIMER

11 LITE TIMER RTC1 Interrupt LTCSR yes FFE4h-FFE5h

LITE TIMER Input Capture Interrupt LTCSR no FFE6h-FFE7h

12 SPI SPI Peripheral Interrupts SPICSR yes no FFE2h-FFE3h 13 Not usedNot used FFE0h-FFE1h

PWMxCSR

or ATCSR

Lowest Priority

Exit

from

ACTIVE

-HALT

Address

Vector

FFFCh-FFFDh FFFAh-FFFBh

FFF8h-FFF9h

FFECh-FFEDh

FFEAh-FFEBh

Note 1: This interrupt exits the MCU from “Auto Wake-up from Halt” mode only.

35/133

ST7LITE2

INTERRUPTS (Cont’d)

EXTERNAL INTERRUPT CONTROL REGISTER (EICR)

Read/Write Reset Value: 0000 0000 (00h)

IS31 IS30 IS21 IS20 IS11 IS10 IS01 IS00

Bit 7:6 = IS3[1:0] ei3 sensitivity These bits define the interrupt sensitivity for ei3 (Port B0) according to Table 6.

EXTERNAL INTERRUPT SELECTION REGISTER (EISR)

Read/Write Reset Value: 0000 1100 (0Ch)

ei31 ei30 ei21 ei20 ei11 ei10 ei01 ei00

Bit 7:6 = ei3[1:0] ei3 pin selection These bits are written by software. They select the Port B I/O pin used for the ei3 external interrupt according to the table below.

Bit 5:4 = IS2[1:0] ei2 sensitivity These bits define the interrupt sensitivity for ei2 (Port B3) according to Table 6.

Bit 3:2 = IS1[1:0] ei1 sensitivity These bits define the interrupt sensitivity for ei1

External Interrupt I/O pin selection

ei31 ei30 I/O Pin

0 0 PB0 0 1 PB1 1 0 PB2

(Port A7) according to Table 6.

Note:

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

1. Reset State

These bits define the interrupt sensitivity for ei0 (Port A0) according to Table 6.

Notes:

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” on page 46.

Table 6. 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

Bits 5:4 = ei2[1:0] ei2 pin selection These bits are written by software. They select the Port B I/O pin used for the ei2 external interrupt according to the table below.

External Interrupt I/O pin selection

ei21 ei20 I/O Pin

0 0 PB3 0 1 PB4 1 0 PB5 1 1 PB6

Notes:

1. Reset State

2. PB4 cannot be used as an external interrupt in HALT mode.

36/133

INTERRUPTS (Cont’d) Bit 3:2 = ei1[1:0] ei1 pin selection

These bits are written by software. They select the Port A I/O pin used for the ei1 external interrupt according to the table below.

External Interrupt I/O pin selection

ei11 ei10 I/O Pin

0 0 PA4 0 1 PA5 1 0 PA6 1 1 PA7*

ST7LITE2

Port A I/O pin used for the ei0 external interrupt according to the table below.

External Interrupt I/O pin selection

ei01 ei00 I/O Pin

0 0 PA0 * 0 1 PA1 1 0 PA2 1 1 PA3

* Reset State

Bits 1:0 = ei0[1:0] ei0 pin selection These bits are written by software. They select the

Bits 1:0 = Reserved.

37/133

ST7LITE2

9 POWER SAVING MODES

9.1 INTRODUCTION

To give a large measure of flexibility to the application in terms of power consumption, five main power saving modes are implemented in the ST7 (see

Figure 21):

■ Slow

■ Wait (and Slow-Wait)

■ Active Halt

■ Auto Wake up 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 divided or multiplied by 2

OSC2

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 21. Power Saving Mode Transitions

High

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

CPU

) to

the available supply voltage.

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 enter-

ing WAIT mode while the device is already in SLOW mode.

Figure 22. SLOW Mode Clock Transition

/32 f

CPU

OSC

RUN

SLOW

WAIT

SLOW WAIT

ACTIVE HALT

AUTO WAKE UP FROM HALT

HALT

POWER CONSUMPTION

SMS

NORMAL RUN MODE

REQUEST

Low

38/133

POWER SAVING MODES (Cont’d)

ST7LITE2

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 23.

Figure 23. WAIT Mode Flow-chart

OSCILLATOR

WFI INSTRUCTION

INTERRUPT

PERIPHERALS CPU IBIT

RESET

OSCILLATOR PERIPHERALS CPU IBIT

256 OR 4096 CPU CLOCK

CYCLE DELAY

OSCILLATOR PERIPHERALS CPU IBIT

ON ON

OFF

ON ON ON X

FETCH RESET VECTOR

OR SERVICE INTERRUPT

Note:

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.

39/133

ST7LITE2

POWER SAVING MODES (Cont’d)

9.4 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 is disabled (see section 9.5 on page 41 for more details) and when the AWUEN bit in the AWUCSR register is cleared.

The MCU can exit HALT mode on reception of either a specific interrupt (see Table 5, “Interrupt Mapping,” on page 35) or a RESET. When exiting HALT mode by means of a RESET or an interrupt, the oscillator is immediately turned on and the 256 or 4096 CPU cycle delay is used to stabilize the oscillator. After the start up delay, the CPU resumes operation by servicing the interrupt or by fetching the reset vector which woke it up (see Fig-

ure 25).

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 up immediately.

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

The compatibility of Watchdog operation with HALT mode is configured by the “WDGHALT” option bit of the option byte. The HALT instruction when executed while the Watchdog system is enabled, can generate a Watchdog RESET (see sec-

tion 15.1 on page 122 for more details).

Figure 24. HALT Timing Overview

Figure 25. HALT Mode Flow-chart

HALT INSTRUCTION

(Active Halt disabled)

(AWUCSR.AWUEN=0)

WATCHDOG

RESET

CYCLE

WDGHALT

WATCHDOG

RESET

INTERRUPT

ENABLE

OSCILLATOR PERIPHERALS CPU IBIT

256 OR 4096 CPU CLOCK

OSCILLATOR PERIPHERALS CPU IBIT

FETCH RESET VECTOR

OR SERVICE INTERRUPT

DISABLE

DELAY

OFF OFF OFF

OFF

ON X

ON ON ON X

HALTRUN RUN

HALT

INSTRUCTION

[Active Halt disabled]

40/133

256 OR 4096 CPU

CYCLE DELAY

RESET

INTERRUPT

FETCH

VECTOR

Notes:

1. WDGHALT is an option bit. See option byte sec-

tion 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 5 Interrupt Mapping for 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 whenthe CC register is popped.

5. If the PLL is enabled by option byte, it outputs the clock after a delay of t

STARTUP

(see Figure 12).

POWER SAVING MODES (Cont’d)

9.4.1 Halt Mode Recommendations

– Make sure that an external event is available to

wake up the microcontroller from Halt mode.

– When using an external interrupt to wake up the

microcontroller, reinitialize the corresponding I/O as “Input Pull-up with Interrupt” before executing the HALT instruction. The main reason for this is that the I/O may be wrongly configured due to external interference or by an unforeseen logical condition.

– For the same reason, reinitialize the level sensi-

tiveness 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 program memory with the value 0x8E.

– As the HALT instruction clears the interrupt mask

in the CC register to allow interrupts, the user may choose to clear all pending interrupt bits before executing the HALT instruction. This avoids entering other peripheral interrupt routines after executing the external interrupt routine corresponding to the wake-up event (reset or external interrupt).

ST7LITE2

9.5 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. The decision to enter either in ACTIVEHALT or HALT mode is given by the LTCSR/ATCSR register status as shown in the following table:

LTCSR1

TB1IE bit

The MCU can exit ACTIVE-HALT mode on reception of a specific interrupt (see Table 5, “Interrupt Mapping,” on page 35) or a RESET.

– When exiting ACTIVE-HALT mode by means of

a RESET, a 256 or 4096 CPU cycle delay occurs. After the start up delay, the CPU resumes operation by fetching the reset vector which woke it up (see Figure 27).

– 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 27).

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 (see Note 3).

In ACTIVE-HALT mode, only the main oscillator and the selected timer counter (LT/AT) are running to keep a wake-up time base. All other peripherals are not clocked except those which get their clock supply from another clock generator (such as external or auxiliary oscillator).

ATCSR

OVFIE

0xx0 00xx 1 xxx x 101

bit

ATCSR CK1 bit

ATCSR CK0 bit

ACTIVE-HALT mode disabled

ACTIVE-HALT mode enabled

Meaning

Note: As soon as ACTIVE-HALT is enabled, exe-

cuting a HALT instruction while the Watchdog is active does not generate a RESET. This means that the device cannot spend more than a defined delay in this power saving mode.

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ST7LITE2

POWER SAVING MODES (Cont’d)

Figure 26. ACTIVE-HALT Timing Overview

ACTIVE

HALTRUN RUN

HALT

INSTRUCTION

[Active Halt Enabled]

256 OR 4096 CPU

CYCLE DELAY

RESET

INTERRUPT

FETCH

VECTOR

Figure 27. ACTIVE-HALT Mode Flow-chart

HALT INSTRUCTION

(Active Halt enabled)

(AWUCSR.AWUEN=0)

INTERRUPT

OSCILLATOR PERIPHERALS CPU IBIT

RESET

OSCILLATOR PERIPHERALS CPU IBIT

256 OR 4096 CPU CLOCK

CYCLE

OSCILLATOR PERIPHERALS CPU IBIT

FETCH RESET VECTOR

OR SERVICE INTERRUPT

DELAY

ON OFF OFF

ON OFF

Notes:

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 RTC1 interrupt and some specific interrupts can exit the MCU from ACTIVE-HALT mode. Refer to Table 5, “Interrupt Mapping,” on page 35 for 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.

9.6 AUTO WAKE UP FROM HALT MODE

Auto Wake Up From Halt (AWUFH) mode is similar to Halt mode with the addition of a specific internal RC oscillator for wake-up (Auto Wake Up from Halt Oscillator). Compared to ACTIVE-HALT mode, AWUFH has lower power consumption (the main clock is not kept running, but there is no accurate realtime clock available.

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

Figure 28. AWUFH Mode Block Diagram

AWU RC

oscillator

AWU_RC

to Timer input capture

AWUFH

/64

divider

AWUFH

prescaler/1 .. 255

interrupt

(ei0 source)

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 AWUF flag is set by hardware and an interrupt wakes-up the MCU from Halt mode. At the same time the main oscillator is immediately turned on and a 256 or 4096 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

AWU_RC

load timer, allowing the f

to the input capture of the 12-bit Auto-Re-

AWU_RC

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

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POWER SAVING MODES (Cont’d)

Similarities with Halt mode

The following AWUFH mode behaviour 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 HALT MODE).

– When entering AWUFH mode, the I bit in the CC

Figure 29. AWUF Halt Timing Diagram

AWU

ST7LITE2

– 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.

RUN MODE HALT MODE 256 OR 4096 t

CPU

AWU_RC

AWUFH interrupt

CPU

RUN MODE

Clear by software

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ST7LITE2

POWER SAVING MODES (Cont’d)

Figure 30. AWUFH Mode Flow-chart Notes:

1. WDGHALT is an option bit. See option byte sec-

HALT INSTRUCTION

(Active-Halt disabled)

(AWUCSR.AWUEN=1)

ENABLE

WDGHALT

WATCHDOG

RESET

WATCHDOG

AWU RC OSC ON

MAIN OSC PERIPHERALS CPU I[1:0] BITS

RESET

DISABLE

OFF OFF OFF

tion 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 5, “Interrupt Mapping,” on page 35 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.

5. If the PLL is enabled by option byte, it outputs the clock after an additional delay of t

Figure 12).

STARTUP

(see

INTERRUPT

AWU RC OSC OFF

MAIN OSC PERIPHERALS CPU I[1:0] BITS

256 OR 4096 CPU CLOCK

AWU RC OSC OFF

MAIN OSC PERIPHERALS CPU I[1:0] BITS

FETCH RESET VECTOR

OR SERVICE INTERRUPT

CYCLE

DELAY

OFF

ON ON ON

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POWER SAVING MODES (Cont’d)

9.6.0.1 Register description

ST7LITE2

AWUFH CONTROL/STATUS REGISTER (AWUCSR)

Read/Write

AWUFH PRESCALER REGISTER (AWUPR)

Read/Write Reset Value: 1111 1111 (FFh)

Reset Value: 0000 0000 (00h)

00000

AWUFAWUMAWU

AWU

PR7

AWU

PR6

AWU

PR5

AWU

PR4

AWU

PR3

Bits 7:0= AWUPR[7:0] Auto Wake Up Prescaler

Bits 7:3 = Reserved.

These 8 bits define the AWUPR Dividing factor (as explained below:

Bit 2 = AWUF Auto Wake Up 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= AWUM Auto Wake Up Measurement This bit enables the AWU RC oscillator and connects its output to the inputcapture of the 12-bit Auto-Reload 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

AWUPR[7:0

FEh 254 FFh 255

In AWU mode, the period that the MCU stays in Halt Mode (t fined by

AWU

This prescaler register can be programmed to modify the time that the MCU stays in Halt mode before waking up automatically.

] Dividing factor

00h Forbidden 01h 1

... ...

in Figure 29 on page 43) is de-

AWU

64 AWUPR×

--------------------------t f

AWURC

Note: If 00h is written to AWUPR, depending on

Bit 0 = AWUEN Auto Wake Up From Halt Enabled This bit enables the Auto Wake Up From Halt feature: once HALT mode is entered, the AWUFH

the product, an interrupt is generated immediately after a HALT instruction, or the AWUPR remains inchanged. l

wakes up the microcontroller after a time delay dependent on the AWU prescaler value. It is set and cleared by software. 0: AWUFH (Auto Wake Up From Halt) mode disa-

bled

1: AWUFH (Auto Wake Up From Halt) mode ena-

bled

AWU

PR2

+×=

AWU

PR1

RCSTRT

AWU

PR0

Table 7. AWU Register Map and Reset Values

Address

(Hex.)

0049h

004Ah

Label

AWUPR

Reset Value

AWUCSR

Reset Value

76543210

AWUPR71AWUPR61AWUPR51AWUPR41AWUPR31AWUPR21AWUPR11AWUPR0

00000AWUFAWUMAWUEN

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ST7LITE2

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 onchip 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 31 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 pull-up. Refer to I/O Port Implementation section for configuration.

Notes:

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.

10.2.1.1 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 in section 2 on page 6 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.

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:

1. To enable an external interrupt:

– set the interrupt mask with the SIM instruction

(in cases where a pin level change could oc-

cur) – select rising edge – enable the external interrupt through the OR

rising edge – reset the interrupt mask with the RIM instruc-

tion (in cases where a pin level change could

occur)

2. To disable an external interrupt: – set the interrupt mask with the SIM instruction

SIM (in cases where a pin level change could occur)

– select falling edge

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ST7LITE2

– disable the external interrupt through the OR

tion (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 opendrain. Refer to I/O Port Implementation section for configuration.

DR Value and Output Pin Status

DR Push-Pull Open-Drain

0V 1VOHFloating

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. The Device Pin Description table 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.

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ST7LITE2

I/O PORTS (Cont’d)

Figure 31. I/O Port General Block Diagram

DATA BUS

DDR SEL

DDR

OR SEL

DR SEL

ALTERNATE OUTPUT

From on-chip peripheral

ALTERNATE ENABLE BIT

If implemented

PULL-UP CONDITION

N-BUFFER

CMOS SCHMITT TRIGGER

P-BUFFER (see table below)

PULL-UP (see table below)

PAD

DIODES (see table below)

ANALOG

INPUT

EXTERNAL INTERRUPT REQUEST (eix)

SENSITIVITY SELECTION

Combinational

Table 8. I/O Port Mode Options

Configuration Mode Pull-Up P-Buffer

Input

Output

Floating with/without Interrupt Off Pull-up with/without Interrupt On Push-pull Open Drain (logic level) Off True Open Drain NI NI NI (see note)

Legend: NI - not implemented

Off - implemented not activated On - implemented and activated

Logic

FROM OTHER BITS

Note: Refer to the Port Configuration table for device specific information.

Off

Note: The diode to V true open drain pads. A local protection between the pad and V vice against positive stress.

ALTERNATE

To on-chip peripheral

Diodes

to V

Off

is implemented to protect the de-

is not implemented in the

INPUT

to V

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I/O PORTS (Cont’d)

Table 9. I/O configurations

ST7LITE2

Hardware Configuration

INPUT

PAD

NOTE 3

PULL-UP CONDITION

INTERRUPT CONDITION

FROM

OTHER

PINS

COMBINATIONAL

DR REGISTER ACCESS

LOGIC

POLARITY SELECTION

DR REGISTER ACCESS

DATA B U S

ALTERNATE INPUT To on-chip peripheral

EXTERNAL INTERRUPT SOURCE (eix)

ANALOG INPUT

R/W

DATA BUS

OPEN-DRAIN OUTPUT

DR REGISTER ACCESS

ALTERNATEALTERNATE

R/W

DATA B U S

PUSH-PULL OUTPUT

PAD

NOTE 3

ENABLE OUTPUT

BIT From on-chip peripheral

Notes:

1. When the I/O port is in input configuration and the associated alternate function is enabled as an output, reading the DR register will read the alternate function output status.

2. When the I/O port is in output configuration and the associated alternate function is enabled as an input, the alternate function reads the pin status given by the DR register content.

3. For true open drain, these elements are not implemented.

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I/O PORTS (Cont’d) 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.

WARNING: The analog input voltage level must be within the limits stated in the absolute maximum ratings.

Figure 32. Interrupt I/O Port State Transitions

INPUT

floating/pull-up

interrupt

INPUT

floating

(reset state)

OUTPUT

open-drain

OUTPUT

push-pull

= DDR, OR

10.4 UNUSED I/O PINS

Unused I/O pins must be connected to fixed voltage levels. Refer to Section 13.8.

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 32. Other transitions are potentially risky and should be avoided, since they may present unwanted side-effects such as spurious interrupt generation.

10.5 LOW POWER MODES

Mode Description

WAIT

HALT

No effect on I/O ports. External interrupts cause the device to exit from WAIT mode.

No effect on I/O ports. External interrupts cause the device to exit from HALT mode.

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).

Interrupt Event

External interrupt on selected external event

Event

Flag

Enable

Control

Bit

DDRx

ORx

Exit

from

Wait

Yes Yes

Exit

from

Halt

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I/O PORTS (Cont’d)

10.7 DEVICE-SPECIFIC I/O PORT CONFIGURATION

ST7LITE2

The I/O port register configurations are summarised as follows.

Standard Ports

PA7:0, PB6:0

MODE DDR OR

floating input 0 0 pull-up input 0 1 open drain output 1 0 push-pull output 1 1

Interrupt Ports Ports where the external interrupt capability is

selected using the EISR register

MODE DDR OR

floating input 0 0 pull-up interrupt input 0 1 open drain output 1 0 push-pull output 1 1

Table 10. Port Configuration (Standard ports)

Port Pin name

Port A PA7:0 floating Port B PB6:0 floating pull-up open drain push-pull

OR = 0 OR = 1 OR = 0 OR = 1

Input Output

pull-up

open drain push-pull

Note: On ports where the external interrupt capability is selected using the EISR register, the configuration will be as follows:

Port Pin name

Port A PA7:0 floating Port B PB6:0 floating pull-up interrupt open drain push-pull

OR = 0 OR = 1 OR = 0 OR = 1

Input Output

pull-up interrupt

open drain push-pull

Table 11. I/O Port Register Map and Reset Values

Address

(Hex.)

0000h

0001h

0002h

0003h

0004h

0005h

Label

PADR

Reset Value

PADDR

Reset Value

PAOR

Reset Value

PBDR

Reset Value

PBDDR

Reset Value

PBOR

Reset Value

76543210

MSB

1111111

MSB

0000000

MSB

0100000

MSB

1111111

MSB

0000000

MSB

0000000

LSB

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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

Figure 33. Watchdog Block Diagram

RESET

■ 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.

CPU

WATCHDOG CONTROL REGISTER (CR)

WDGA

7-BIT DOWNCOUNTER

CLOCK DIVIDER

÷16000

52/133

WATCHDOG TIMER (Cont’d) The application program must write in the CR reg-

ister at regular intervals during normal operation to prevent an MCU reset. This downcounter is freerunning: 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 12

.Watchdog Timing):

– The WDGA bit is set (watchdog enabled) – The T6 bit is set to prevent generating an imme-

diate 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 12.Watchdog Timing

= 8MHz

CPU

WDG

Counter

Code

C0h 1 2 FFh 127 128

min

[ms]

max [ms]

ST7LITE2

Notes:

1. The timing variation shown in Table 12 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 15

on page 122.

11.1.4.1 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.

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WATCHDOG TIMER (Cont’d)

11.1.5 Interrupts

None.

11.1.6 Register Description

CONTROL REGISTER (CR)

Read/Write Reset Value: 0111 1111 (7Fh)

WDGA T6 T5 T4 T3 T2 T1 T0

Bit 7 = WDGA Activation bit. This bit is set by software and only cleared by hardware after a reset.

When WDGA = 1, the watchdog can generate a reset. 0: Watchdog disabled 1: Watchdog enabled

Note: This bit is not used if the hardware watchdog option is enabled by option byte.

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 13. Watchdog Timer Register Map and Reset Values

Address

(Hex.)

002Eh

Label

WDGCR

Reset Value

76543210

WDGA

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11.2 12-BIT AUTORELOAD TIMER 2 (AT2)

ST7LITE2

11.2.1 Introduction

The 12-bit Autoreload Timer can be used for general-purpose timing functions. It is based on a freerunning 12-bit upcounter with an input capture register and four PWM output channels. There are 6 external pins:

– Four PWM outputs – ATIC pin for the Input Capture function – BREAK pin for forcing a break condition on the

PWM outputs

11.2.2 Main Features

■ 12-bit upcounter with 12-bit autoreload register

(ATR)

Figure 34. Block Diagram

ATIC

LTIMER

(1 ms timebase

@ 8MHz)

CPU

32 MHz

ATICR

ATCSR

12-BIT INPUT CAPTURE REGISTER

IC INTERRUPT

REQUEST

COUNTER

CNTR

ATR

■ Maskable overflow interrupt

■ Generation of four independent PWMx signals

■ Frequency 2KHz-4MHz (@ 8 MHz f

CPU

– Programmable duty-cycles – Polarity control – Programmable output modes – Maskable Compare interrupt

■ Input Capture

– 12-bit input capture register (ATICR) – Triggered by rising and falling edges – Maskable IC interrupt

OVF INTERRUPT REQUEST

CMPIEOVFIEOVFCK0CK1ICIEICF0

CMPF0 CMPF1 CMPF2 CMPF3

12-BIT UPCOUNTER

12-BIT AUTORELOAD REGISTER

CMP INTERRUPT REQUEST

)

DCR0H

Preload

DCR0L

Preload

on OVF Event IF TRAN=1

12-BIT DUTY CYCLE VALUE (shadow)

4 PWM Channels

CMPFx bit

COMP-

PARE

PWM GENERATION

PWM

OPx bit

POLARITY

OEx bit

PWMx

OUTPUT CONTROL

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12-BIT AUTORELOAD TIMER (Cont’d)

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. The PWMx output signals can be enabled or disabled using the OEx bits in the PWMCR register.

PWM Frequency and Duty Cycle

The four PWM signals have the same frequency

) which is controlled by the counter period

PWM

and the ATR register value.

= f

PWM

COUNTER

Following the above formula, – If f

COUNTER

is 8 MHz (ATR register value = 4092), the

PWM

is 32 MHz, the maximum value of

minimum value is 8 KHz (ATR register value = 0)

– If f

COUNTER

is 4 Mhz, the maximum value of f is 2 MHz (ATR register value = 4094),the minimum value is 1 KHz (ATR register value = 0).

Note: The maximum value of ATR is 4094 because it must be lower than the DCR value which must be 4095 in this case.

At reset, the counter starts counting from 0.

When a upcounter overflow occurs (OVF event), the preloaded Duty cycle values are transferred to the Duty Cycle registers and the PWMx signals are set to a high level. When the upcounter matches the DCRx value the PWMx signals are set to a low level. To obtain a signal on a PWMx pin, the

/ (4096 - ATR)

PWM

contents of the corresponding DCRx register must be greater than the contents of the ATR register.

The polarity bits can be used to invert any of the four output signals. The inversion is synchronized with the counter overflow if the TRAN bit in the TRANCR register is set (reset value). See Figure

35.

Figure 35. PWM Inversion Diagram

inverter

PWMx

PWMxCSR Register

OPx

TRANCR Register

TRAN

counter

overflow

DFF

The maximum available resolution for the PWMx duty cycle is:

Resolution = 1 / (4096 - ATR)

Note: To get the maximum resolution (1/4096), the ATR register must be 0. With this maximum resolution, 0% and 100% can be obtained by changing the polarity.

PWMx PIN

Figure 36. PWM Function

4095

DUTY CYCLE

(DCRx)

AUTO-RELOAD

COUNTER

(ATR)

000

WITH OE=1 AND OPx=0

WITH OE=1 AND OPx=1

PWMx OUTPUT

56/133

12-BIT AUTORELOAD TIMER (Cont’d)

Figure 37. PWM Signal from 0% to 100% Duty Cycle

COUNTER

ATR= FFDh

ST7LITE2

PWMx OUTPUTtWITH OEx=1

PWMx OUTPUT

WITH OEx=1

AND OPx=0

AND OPx=1

COUNTER

DCRx=000h

DCRx=FFDh

DCRx=FFEh

DCRx=000h

FFDh FFEh FFFh FFDh FFEh FFFh FFDh FFEh

Output Compare Mode

To use this function, load a 12-bit value in the DCRxH and DCRxL registers.

When the 12-bit upcounter (CNTR) reaches the value stored in the DCRxH and DCRxL registers, the CMPF bit in the PWMxCSR register is set and an interrupt request is generated if the CMPIE bit is set.

Note: The output compare function is only available for DCRx values other than 0 (reset value).

Break Function

The break function is used to perform an emergency shutdown of the power converter.

The break function is activated by the external BREAK pin (active low). In order to use the BREAK pin it must be previously enabled by software setting the BPEN bit in the BREAKCR register.

When a low level is detected on the BREAK pin, the BA bit is set and the break function is activated.

Software can set the BA bit to activate the break function without using the BREAK pin.

When the break function is activated (BA bit =1): – The break pattern (PWM[3:0] bits in the BREAK-

CR) is forced directly on the PWMx output pins

(after the inverter). – The 12-bit PWM counter is set to its reset value. – The ARR, DCRx and the corresponding shadow

registers are set to their reset values. – The PWMCR register is reset. When the break function is deactivated after ap-

plying the break (BA bit goes from 1 to 0 by software):

– The control of PWM outputs is transferred to the

port registers.

57/133

ST7LITE2

12-BIT AUTORELOAD TIMER (Cont’d)

Figure 38. Block Diagram of Break Function

BREAK pin

(Active Low)

BREAKCR Register

PWM0

PWM1

PWM2

PWM3

Note: The BREAK pin value is latched by the BA bit.

(Inverters)

PWM0PWM1PWM2PWM3BPENBA

PWM0

PWM1

PWM2

PWM3

When BA is set:

PWM counter -> Reset value ARR & DCRx -> Reset value PWM Mode -> Reset value

11.2.3.1 Input Capture

The 12-bit ATICR register is used to latch the value of the 12-bit free running upcounter 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

Figure 39. Input Capture Timing Diagram

COUNTER

ATIC PIN

ICF FLAG

ICR REGISTER

01h

02h 03h 04h 05h 06h 07h

xxh

free running upcounter. An IC interrupt is generated if the ICIE bit is set. The ICF bit is reset by reading the ATICR 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.

08h 09h 0Ah

INTERRUPT

ATICR READ

04h

INTERRUPT

09h

58/133

12-BIT AUTORELOAD TIMER (Cont’d)

11.2.4 Low Power Modes

Mode Description

SLOW

The input frequency is divided by 32

WAIT No effect on AT timer

ACTIVE-HALT

AT timer halted except if CK0=1, CK1=0 and OVFIE=1

HALT AT timer halted

11.2.5 Interrupts

ST7LITE2

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).

Note 2: Only if CK0=1 and CK1=0 (f

)

LTIMER

COUNTER

Exit

Interrupt

Event

Overflow Event

IC Event ICF ICIE Yes No No CMP Event CMPF0 CMPIE Yes No No

Event

Enable

Control

Flag

OVF OVIE Yes No Yes

Bit

Exit from Wait

from

Halt

Exit

from

Active-

Halt

Note 1: The CMP and IC events are connected to the same interrupt vector.

59/133

ST7LITE2

12-BIT AUTORELOAD TIMER (Cont’d)

11.2.6 Register Description

TIMER CONTROL STATUS REGISTER (ATCSR)

Read / Write Reset Value: 0x00 0000 (x0h)

76 0

Bit 2 = OVF Overflow Flag. This bit is set by hardware and cleared by software by reading the TCSR register. It indicates the transition of the counter from FFFh to ATR value. 0: No counter overflow occurred 1: Counter overflow occurred

0 ICF ICIE CK1 CK0 OVF OVFIE CMPIE

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 will clear 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. This bit is set and cleared by software. 0: Input capture interrupt disabled 1: Input capture interrupt enabled

Bits 4:3 = CK[1:0] Counter Clock Selection. These bits are set and cleared by software and cleared by hardware after a reset. They select the clock frequency of the counter.

Counter Clock Selection CK1 CK0

OFF 0 0

(1 ms timebase @ 8 MHz)

LTIMER

CPU

32 MHz

01 10 11

Bit 1 = OVFIE Overflow Interrupt Enable. This bit is read/write by software and cleared by hardware after a reset. 0: OVF interrupt disabled. 1: OVF interrupt enabled.

Bit 0 = CMPIE Compare Interrupt Enable. This bit is read/write by software and cleared by hardware after a reset. It can be used to mask the interrupt generated when the CMPF bit is set. 0: CMPF interrupt disabled. 1: CMPF interrupt enabled.

COUNTER REGISTER HIGH (CNTRH)

Read only Reset Value: 0000 0000 (000h)

15 8

0000

CNTR11CNTR

CNTR9 CNTR8

COUNTER REGISTER LOW (CNTRL)

Read only Reset Value: 0000 0000 (000h)

CNTR7 CNTR6 CNTR5 CNTR4 CNTR3 CNTR2 CNTR1 CNTR0

Note 1: PWM mode and Output Compare modes are not available at this frequency.

Note 2: ATICR counter may return inaccurate results when read. It is therefore not recommended to use Input Capture mode at this frequency.

60/133

Bits 15:12 = Reserved.

Bits 11:0 = CNTR[11:0] Counter Value. This 12-bit register is read by software and cleared by hardware after a reset. The counter is incremented continuously as soon as a counter clok is selected. To obtain the 12-bit value, software should read the counter value in two consecutive read operations, LSB first. When a counter overflow occurs, the counter restarts from the value specified in the ATR register.

12-BIT AUTORELOAD TIMER (Cont’d)

ST7LITE2

AUTORELOAD REGISTER (ATRH)

Read / Write Reset Value: 0000 0000 (00h)

PWMx CONTROL STATUS REGISTER (PWMxCSR)

Read / Write Reset Value: 0000 0000 (00h)

15 8

76 0

0 0 0 0 ATR11 ATR10 ATR9 ATR8

000000OPxCMPFx

AUTORELOAD REGISTER (ATRL)

Read / Write

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

Reset Value: 0000 0000 (00h)

Bit 1 = OPx PWMx Output Polarity. This bit is read/write by software and cleared by

ATR7 ATR6 ATR5 ATR4 ATR3 ATR2 ATR1 ATR0

hardware after a reset. This bit selects the polarity of the PWM signal. 0: The PWM signal is not inverted.

Bits 11:0 = ATR[11:0] Autoreload Register.

1: The PWM signal is inverted.

This is a 12-bit register which is written by software. The ATR register value is automatically loaded into the upcounter when an overflow occurs. The register value is used to set the PWM frequency.

Bit 0 = CMPFx PWMx Compare Flag. This bit is set by hardware and cleared by software by reading the PWMxCSR register. It indicates that the upcounter value matches the DCRx register value.

PWM OUTPUT CONTROL REGISTER (PWMCR)

0: Upcounter value does not match DCR value. 1: Upcounter value matches DCR value.

Read/Write Reset Value: 0000 0000 (00h)

BREAK CONTROL REGISTER (BREAKCR)

Read/Write Reset Value: 0000 0000 (00h)

0OE30OE20OE10OE0

Bits 7:0 = OE[3:0] PWMx output enable. 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 after an overflow event.

1: PWM mode enabled

0 0 BA BPEN PWM3 PWM2 PWM1 PWM0

Bits 7:6 = Reserved. Forced by hardware to 0.

Bit 5 = BA Break Active. This bit is read/write by software, cleared by hardware after reset and set by hardware when the BREAK pin is low. It activates/deactivates the Break function. 0: Break not active 1: Break active

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ST7LITE2

12-BIT AUTORELOAD TIMER (Cont’d)

Bit 4 = BPEN Break Pin Enable. This bit is read/write by software and cleared by hardware after Reset. 0: Break pin disabled 1: Break pin enabled

INPUT CAPTURE REGISTER HIGH (ATICRH)

Read only Reset Value: 0000 0000 (00h)

15 8

Bits 3:0 = PWM[3:0] Break Pattern.

0 0 0 0 ICR11 ICR10 ICR9 ICR8

These bits are read/write by software and cleared by hardware after a reset. They are used to force the four PWMx output signals into a stable state when the Break function is active.

INPUT CAPTURE REGISTER LOW (ATICRL)

Read only Reset Value: 0000 0000 (00h)

PWMx DUTY CYCLE REGISTER HIGH (DCRxH)

Read / Write Reset Value: 0000 0000 (00h)

15 8

ICR7 ICR6 ICR5 ICR4 ICR3 ICR2 ICR1 ICR0

Bits 15:12 = Reserved.

0 0 0 0 DCR11 DCR10 DCR9 DCR8

Bits 11:0 = ICR[11:0] Input Capture Data. This is a 12-bit register which is readable by software and cleared by hardware after a reset. The ATICR register contains captured the value of the

PWMx DUTY CYCLE REGISTER LOW (DCRxL) Read / Write Reset Value: 0000 0000 (00h)

12-bit CNTR register when a rising or falling edge occurs on the ATIC pin. Capture will only be performed when the ICF flag is cleared.

TRANSFER CONTROL REGISTER (TRANCR)

Read/Write

DCR7 DCR6 DCR5 DCR4 DCR3 DCR2 DCR1 DCR0

Reset Value: 0000 0001 (01h)

Bits 15:12 = Reserved.

Bits 11:0 = DCR[11:0] PWMx Duty Cycle Value This 12-bit value is written by software. It definesthe duty cycle of the corresponding PWM output signal (see Figure 36).

In PWM mode (OEx=1 in the PWMCR register) the DCR[11:0] bits define the duty cycle of the PWMx output signal (see Figure 36). In Output Compare mode, they define the value to be compared with the 12-bit upcounter value.

62/133

0000000TRAN

Bits 7:1 Reserved. Forced by hardware to 0.

Bit 0 = TRAN Transfer enable This bit is read/write by software, cleared by hardware after each completed transfer and set by hardware after reset.

It allows the value of the DCRx registers to be transferred to the DCRx shadow registers after the next overflow event.

The OPx bits are transferred to the shadow OPx bits in the same way.

12-BIT AUTORELOAD TIMER (Cont’d)

Table 14. Register Map and Reset Values

ST7LITE2

Address

(Hex.)

Label

ATCSR

Reset Value

CNTRH

Reset Value

CNTRL

Reset Value

ATRH

Reset Value

ATRL

Reset Value

PWMCR

Reset Value

PWM0CSR

Reset Value

PWM1CSR

Reset Value

PWM2CSR

Reset Value

PWM3CSR

Reset Value

DCR0H

Reset Value

DCR0L

Reset Value

DCR1H

Reset Value

DCR1L

Reset Value

DCR2H

Reset Value

DCR2L

Reset Value

DCR3H

Reset Value

DCR3L

Reset Value

ATICRH

Reset Value

ATICRL

Reset Value

76543210

0000

CNTR70CNTR80CNTR70CNTR60CNTR30CNTR20CNTR10CNTR0

0000

ATR7

000000

0000

DCR7

0000

DCR7

0000

DCR7

0000

DCR7

0000

ICR7

ICF

ATR6

OE3

DCR6

ICR6

ICIE

ATR5

DCR5

ICR5

CK1

ATR4

OE2

DCR4

ICR4

CK0

CNTR110CNTR100CNTR90CNTR8

ATR110ATR100ATR9

ATR3

DCR110DCR100DCR90DCR8

DCR30DCR2

DCR110DCR100DCR90DCR8

DCR30DCR2

DCR110DCR10

DCR30DCR2

DCR110DCR100DCR90DCR8

DCR30DCR2

ICR110ICR10

ICR3

OVF

ATR2

OE1

ICR2

OVFIE0CMPIE

ATR8

ATR1

OP0

OP1

OP2

OP3

DCR10DCR0

DCR90DCR8

DCR10DCR0

ICR9

ICR1

ATR0

OE0

CMPF0

CMPF1

CMPF2

CMPF3

ICR8

ICR0

63/133

ST7LITE2

Address

(Hex.)

Label

TRANCR

Reset Value

BREAKCR

Reset Value

76543210

0000000

BPEN0PWM30PWM20PWM10PWM0

TRAN

64/133

11.3 LITE TIMER 2 (LT2)

ST7LITE2

11.3.1 Introduction

The Lite Timer can be used for general-purpose timing functions. It is based on two free-running 8bit upcounters, an 8-bit input capture register.

11.3.2 Main Features

■ Realtime Clock

– One 8-bit upcounter 1 ms or 2 ms timebase

period (@ 8 MHz f

OSC

)

Figure 40. Lite Timer 2 Block Diagram

/32

OSC

LTCNTR

8-bit TIMEBASE

COUNTER 2

LTARR

8-bit AUTORELOAD

LTCSR2

– One 8-bit upcounter with autoreload and pro-

– 2 Maskable timebase interrupts

■ Input Capture

– 8-bit input capture register (LTICR) – Maskable interrupt with wakeup from Halt

grammable timebase period from 4µs to

1.024ms in 4µs increments (@ 8 MHz f

OSC

)

Mode capability

LTTB2

Interrupt request

TB2IE

LTIMER

TB2F

To 12-bit AT TImer

LTIC

8-bit TIMEBASE

COUNTER 1

LTICR

8-bit

INPUT CAPTURE

LTIMER

LTCSR1

Timebase 1 or 2 ms (@ 8MHz f

OSC

)

TB1F TB1IETBICFICIE

LTTB1 INTERRUPT REQUEST

LTIC INTERRUPT REQUEST

65/133

ST7LITE2

LITE TIMER (Cont’d)

11.3.3 Functional Description

11.3.3.1 Timebase Counter 1

The 8-bit value of Counter 1 cannot be read or written by software. After an MCU reset, it starts incrementing from 0 at a frequency of f overflow event occurs when the counter rolls over from F9h to 00h. If f

= 8 MHz, then the time pe-

OSC

riod between two counter overflow events is 1 ms. This period can be doubled by setting the TB bit in the LTCSR1 register.

When Counter 1 overflows, the TB1F bit is set by hardware and an interrupt request is generated if the TB1IE bit is set. The TB1F bit is cleared by software reading the LTCSR1 register.

11.3.3.2 Input Capture

The 8-bit input capture register is used to latch the free-running upcounter (Counter 1) 1 after a rising or falling edge is detected on the LTIC pin. When an input capture occurs, the ICF bit is set and the LTICR1 register contains the MSB of Counter 1.

OSC

/32. An

An interrupt is generated if the ICIE bit is set. The ICF bit is cleared by reading the LTICR register.

The LTICR is a read-only register and always contains the data from the last input capture. Input capture is inhibited if the ICF bit is set.

11.3.3.3 Timebase Counter 2

Counter 2 is an 8-bit autoreload upcounter. It can be read by accessing the LTCNTR register. After an MCU reset, it increments at a frequency of

/32 starting from the value stored in the

OSC

LTARR register. A counter overflow event occurs when the counter rolls over from FFh to the LTARR reload value. Software can write a new value at anytime in the LTARR register, this value will be automatically loaded in the counter when the next overflow occurs.

When Counter 2 overflows, the TB2F bit in the LTCSR2 register is set by hardware and an interrupt request is generated if the TB2IE bit is set. The TB2F bit is cleared by software reading the LTCSR2 register.

Figure 41. Input Capture Timing Diagram.

4µs

CPU

/32

OSC

8-bit COUNTER 1

LTIC PIN

ICF FLAG

LTICR REGISTER

(@ 8MHz f

01h

)

OSC

02h 03h 05h 06h 07h

xxh

04h

CLEARED

BY S/W

READING

LTIC REGISTER

07h

66/133

LITE TIMER (Cont’d)

11.3.4 Low Power Modes

ST7LITE2

11.3.6 Register Description

Mode Description

No effect on Lite timer

SLOW

(this peripheral is driven directly

OSC

/32)

by f WAIT No effect on Lite timer ACTIVE-HALT No effect on Lite timer HALT Lite timer stops counting

11.3.5 Interrupts

Exit

from

Wait

Flag

Enable

Control

Bit

Interrupt

Event

Timebase 1 Event

Timebase 2 Event

IC Event ICF ICIE Yes No No

Event

TB1F TB1IE Yes Yes No

TB2F TB2IE Yes No No

Exit

from

Active

Halt

Exit

from

Halt

Note: The TBxF and ICF interrupt events are con-

nected to separate interrupt vectors (see Interrupts chapter).

They generate an interrupt if the enable bit is set in the LTCSR1 or LTCSR2 register and the interrupt mask in the CC register is reset (RIM instruction).

LITE TIMER CONTROL/STATUS REGISTER 2 (LTCSR2)

Read / Write Reset Value: 0000 0000 (00h)

000000TB2IETB2F

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

Bit 1 = TB2IE Timebase 2 Interrupt enable. This bit is set and cleared by software. 0: Timebase (TB2) interrupt disabled 1: Timebase (TB2) interrupt enabled

Bit 0 = TB2F Timebase 2 Interrupt Flag. This bit is set by hardware and cleared by software reading the LTCSR register. Writing to this bit has no effect. 0: No Counter 2 overflow 1: A Counter 2 overflow has occurred

LITE TIMER AUTORELOAD REGISTER (LTARR)

Read / Write Reset Value: 0000 0000 (00h)

AR7 AR7 AR7 AR7 AR3 AR2 AR1 AR0

Bits 7:0 = AR[7:0] Counter 2 Reload Value. These bits register is read/write by software. The LTARR value is automatically loaded into Counter 2 (LTCNTR) when an overflow occurs.

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ST7LITE2

LITE TIMER (Cont’d)

LITE TIMER COUNTER 2 (LTCNTR)

Read only Reset Value: 0000 0000 (00h)

CNT7 CNT7 CNT7 CNT7 CNT3 CNT2 CNT1 CNT0

Bit 5 = TB Timebase period selection. This bit is set and cleared by software. 0: Timebase period = t 1: Timebase period = t

* 8000 (1ms @ 8 MHz)

OSC

* 16000 (2ms @ 8

OSC

MHz)

Bit 4 = TB1IE Timebase Interrupt enable. This bit is set and cleared by software.

Bits 7:0 = CNT[7:0] Counter 2 Reload Value. This register is read by software. The LTARR val-

0: Timebase (TB1) interrupt disabled 1: Timebase (TB1) interrupt enabled

ue is automatically loaded into Counter 2 (LTCNTR) when an overflow occurs.

Bit 3 = TB1F Timebase Interrupt Flag. This bit is set by hardware and cleared by software

LITE TIMER CONTROL/STATUS REGISTER (LTCSR1)

Read / Write Reset Value: 0x00 0000 (x0h)

reading the LTCSR register. Writing to this bit has no effect. 0: No counter overflow 1: A counter overflow has occurred

Bits 2:0 = Reserved

ICIE ICF TB TB1IE TB1F - - -

LITE TIMER INPUT CAPTURE REGISTER (LTICR)

Read only

Bit 7 = ICIE Interrupt Enable.

Reset Value: 0000 0000 (00h)

This bit is set and cleared by software. 0: Input Capture (IC) interrupt disabled

1: Input Capture (IC) interrupt enabled

ICR7 ICR6 ICR5 ICR4 ICR3 ICR2 ICR1 ICR0

Bit 6 = ICF Input Capture Flag. This bit is set by hardware and cleared by software by reading the LTICR register. Writing to this bit does not change the bit value. 0: No input capture 1: An input capture has occurred

Note: After an MCU reset, software must initialise

Bits 7:0 = ICR[7:0] Input Capture Value These bits are read by software and cleared by hardware after a reset. If the ICF bit in the LTCSR is cleared, the value of the 8-bit up-counter will be captured when a rising or falling edge occurs on the LTIC pin.

the ICF bit by reading the LTICR register

68/133

LITE TIMER (Cont’d)

Table 15. Lite Timer Register Map and Reset Values

ST7LITE2

Address

(Hex.)

Label

LTCSR2

Reset Value

LTARR

Reset Value

LTCNTR

Reset Value

LTCSR1

Reset Value

LTICR

Reset Value

76543210

000000

AR7

CNT7

ICIE

ICR7

AR6

CNT6

ICF

ICR6

AR5

CNT5

ICR5

AR4

CNT4

TB1IE

ICR4

AR3

CNT3

TB1F

ICR3

AR2

CNT2

000

ICR2

TB2IE

AR1

CNT1

ICR1

TB2F

AR0

CNT0

ICR0

69/133

ST7LITE2

11.4 SERIAL PERIPHERAL INTERFACE (SPI)

11.4.1 Introduction

The Serial Peripheral Interface (SPI) allows fullduplex, synchronous, serial communication with external devices. An SPI system may consist of a master and one or more slaves or a system in which devices may be either masters or slaves.

11.4.2 Main Features

■ Full duplex synchronous transfers (on 3 lines)

■ Simplex synchronous transfers (on 2 lines)

■ Master or slave operation

■ Six master mode frequencies (f

■ f

■ SS Management by software or hardware

■ Programmable clock polarity and phase

■ End of transfer interrupt flag

■ Write collision, Master Mode Fault and Overrun

/2 max. slave mode frequency (see note)

CPU

/4 max.)

flags

Note: In slave mode, continuous transmission is not possible at maximum frequency due to the software overhead for clearing status flags and to initiate the next transmission sequence.

Figure 42. Serial Peripheral Interface Block Diagram

Data/Address Bus

SPIDR

Read Buffer

Read

11.4.3 General Description

Figure 42 shows the serial peripheral interface

(SPI) block diagram. There are 3 registers:

– SPI Control Register (SPICR) – SPI Control/Status Register (SPICSR) – SPI Data Register (SPIDR)

The SPI is connected to external devices through 3 pins:

– MISO: Master In / Slave Out data – MOSI: Master Out / Slave In data – SCK: Serial Clock out by SPI masters and in-

put by SPI slaves

: Slave select:

–SS

This input signal acts as a ‘chip select’ to let the SPI master communicate with slaves individually and to avoid contention on the data lines. Slave SS ard I/O ports on the master

inputs can be driven by stand-

Device.

Interrupt

request

MOSI

MISO

SCK

70/133

SOD

bit

8-Bit Shift Register

Write

MASTER

CONTROL

SERIAL CLOCK

GENERATOR

SPIF WCOL MODF

SPIE SPE

OVR SSISSMSOD

SPI

STATE

CONTROL

MSTR

SPR2

CPOL

CPHA

SPICSR

SPICR

SPR1

SPR0

SERIAL PERIPHERAL INTERFACE (Cont’d)

11.4.3.1 Functional Description

A basic example of interconnections between a single master and a single slave is illustrated in

Figure 43.

The MOSI pins are connected together and the MISO pins are connected together. In this way data is transferred serially between master and slave (most significant bit first).

The communication is always initiated by the master. When the master device transmits data to a slave device via MOSI pin, the slave device re-

Figure 43. Single Master/ Single Slave Application

ST7LITE2

sponds by sending data to the master device via the MISO pin. This implies full duplex communication with both data out and data in synchronized with the same clock signal (which is provided by the master device via the SCK pin).

To use a single data line, the MISO and MOSI pins must be connected at each node ( in this case only simplex communication is possible).

Four possible data/clock timing relationships may be chosen (see Figure 46) but master and slave must be programmed with the same timing mode.

MASTER

MSBit LSBit MSBit LSBit

+5V

MISO

MOSI

SCK

8-BIT SHIFT REGISTER

SPI

CLOCK

GENERATOR

MISO

MOSI

SCK

SLAVE

Not used if SS is managed by software

71/133

ST7LITE2

SERIAL PERIPHERAL INTERFACE (Cont’d)

11.4.3.2 Slave Select Management

As an alternative to using the SS Slave Select signal, the application can choose to manage the Slave Select signal by software. This is configured by the SSM bit in the SPICSR register (see Figure 45)

In software management, the external SS free for other application uses and the internal SS signal level is driven by writing to the SSI bit in the SPICSR register.

In Master mode:

internal must be held high continuously.

pin to control the

pin is

In Slave Mode:

There are two cases depending on the data/clock timing relationship (see Figure 44):

If CPHA=1 (data latched on 2nd clock edge):

–SS

internal must be held low during the entire transmission. This implies that in single slave applications the SS V

, or made free for standard I/O by manag-

ing the SS

function by software (SSM= 1 and

pin either can be tied to

SSI=0 in the in the SPICSR register)

If CPHA=0 (data latched on 1st clock edge):

–SS

internal must be held low during byte transmission and pulled high between each byte to allow the slave to write to the shift register. If SS

is not pulled high, a Write Collision error will occur when the slave writes to the shift register (see Section 11.4.5.3).

Figure 44. Generic SS

MOSI/MISO

Master SS

Slave SS

(if CPHA=0)

Slave SS

(if CPHA=1)

Timing Diagram

Byte 1 Byte 2

Figure 45. Hardware/Software Slave Select Management

SSM bit

external pin

SSI bit

SS internal

Byte 3

72/133

SERIAL PERIPHERAL INTERFACE (Cont’d)

11.4.3.3 Master Mode Operation

In master mode, the serial clock is output on the SCK pin. The clock frequency, polarity and phase are configured by software (refer to the description of the SPICSR register).

Note: The idle state of SCK must correspond to the polarity selected in the SPICSR register (by pulling up SCK if CPOL=1 or pulling down SCK if CPOL=0).

How to operate the SPI in master mode

To operate the SPI in master mode, perform the following steps in order (if the SPICSR register is not written first, the SPICR register setting (MSTR bit ) may be not taken into account):

1. Write to the SPICR register: – Select the clock frequency by configuring the

SPR[2:0] bits.

– Select the clock polarity and clock phase by

configuring the CPOL and CPHA bits. Figure

46 shows the four possible configurations.

Note: The slave must have the same CPOL and CPHA settings as the master.

2. Write to the SPICSR register: – Either set the SSM bit and set the SSI bit or

clear the SSM bit and tie the SS the complete byte transmit sequence.

3. Write to the SPICR register: – Set the MSTR and SPE bits

Note: MSTR and SPE bits remain set only if SS

is high.

Important note: if the SPICSR register is not written first, the SPICR register setting (MSTR bit) may be not taken into account.

The transmit sequence begins when software writes a byte in the SPIDR register.

11.4.3.4 Master Mode Transmit Sequence

When software writes to the SPIDR register, the data byte is loaded into the 8-bit shift register and then shifted out serially to the MOSI pin most significant bit first.

When data transfer is complete:

– The SPIF bit is set by hardware – An interrupt request is generated if the SPIE

bit is set and the interrupt mask in the CCR register is cleared.

Clearing the SPIF bit is performed by the following software sequence:

1. An access to the SPICSR register while the SPIF bit is set

pin high for

ST7LITE2

2. A read to the SPIDR register. Note: While the SPIF bit is set, all writes to the

SPIDR register are inhibited until the SPICSR register is read.

11.4.3.5 Slave Mode Operation

In slave mode, the serial clock is received on the SCK pin from the master device.

To operate the SPI in slave mode:

1. Write to the SPICSR register to perform the following actions:

– Select the clock polarity and clock phase by

configuring the CPOL and CPHA bits (see

Figure 46).

Note: The slave must have the same CPOL and CPHA settings as the master.

– Manage the SS

11.4.3.2 and Figure 44. If CPHA=1 SS

be held low continuously. If CPHA=0 SS be held low during byte transmission and pulled up between each byte to let the slave write in the shift register.

2. Write to the SPICR register to clear the MSTR bit and set the SPE bit to enable the SPI I/O functions.

11.4.3.6 Slave Mode Transmit Sequence

When software writes to the SPIDR register, the data byte is loaded into the 8-bit shift register and then shifted out serially to the MISO pin most significant bit first.

The transmit sequence begins when the slave device receives the clock signal and the most significant bit of the data on its MOSI pin.

When data transfer is complete:

– The SPIF bit is set by hardware – An interrupt request is generated if SPIE bit is

set and interrupt mask in the CCR register is cleared.

Clearing the SPIF bit is performed by the following software sequence:

1. An access to the SPICSR register while the SPIF bit is set.

2. A write or a read to the SPIDR register.

Notes: While the SPIF bit is set, all writes to the SPIDR register are inhibited until the SPICSR register is read.

The SPIF bit can be cleared during a second transmission; however, it must be cleared before the second SPIF bit in order to prevent an Overrun condition (see Section 11.4.5.2).

pin as described in Section

must

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ST7LITE2

SERIAL PERIPHERAL INTERFACE (Cont’d)

11.4.4 Clock Phase and Clock Polarity

Four possible timing relationships may be chosen by software, using the CPOL and CPHA bits (See

Figure 46).

Note: The idle state of SCK must correspond to the polarity selected in the SPICSR register (by pulling up SCK if CPOL=1 or pulling down SCK if CPOL=0).

The combination of the CPOL clock polarity and CPHA (clock phase) bits selects the data capture clock edge

Figure 46. Data Clock Timing Diagram

SCK (CPOL = 1)

SCK (CPOL = 0)

Figure 46, shows an SPI transfer with the four

combinations of the CPHA and CPOL bits. The diagram may be interpreted as a master or slave timing diagram where the SCK pin, the MISO pin, the MOSI pin are directly connected between the master and the slave device.

Note: If CPOL is changed at the communication byte boundaries, the SPI must be disabled by resetting the SPE bit.

CPHA =1

MISO

(from master)

MOSI

(from slave)

(to slave)

CAPTURE STROBE

SCK (CPOL = 1)

SCK (CPOL = 0)

MISO

(from master)

MOSI

(from slave)

(to slave)

CAPTURE STROBE

MSBit Bit 6 Bit 5

Bit 4 Bit3 Bit 2 Bit 1 LSBit

Bit 4 Bit3Bit 2Bit 1LSBit

CPHA =0

Bit 4 Bit3 Bit 2 Bit 1 LSBit

74/133

Note:

This figure should not be used as a replacement for parametric information.

Refer to the Electrical Characteristics chapter.

SERIAL PERIPHERAL INTERFACE (Cont’d)

11.4.5 Error Flags

11.4.5.1 Master Mode Fault (MODF)

Master mode fault occurs when the master device has its SS

pin pulled low.

When a Master mode fault occurs:

– The MODF bit is set and an SPI interrupt re-

quest is generated if the SPIE bit is set.

– The SPE bit is reset. This blocks all output

from the Device and disables the SPI peripheral.

– The MSTR bit is reset, thus forcing the Device

into slave mode.

Clearing the MODF bit is done through a software sequence:

1. A read access to the SPICSR register while the MODF bit is set.

2. A write to the SPICR register.

Notes: To avoid any conflicts in an application with multiple slaves, the SS

pin must be pulled high during the MODF bit clearing sequence. The SPE and MSTR bits may be restored to their original state during or after this clearing sequence.

Hardware does not allow the user to set the SPE and MSTR bits while the MODF bit is set except in the MODF bit clearing sequence.

In a slave device, the MODF bit can not be set, but in a multi master configuration the

Device can be in

slave mode with the MODF bit set. The MODF bit indicates that there might have

been a multi-master conflict and allows software to handle this using an interrupt routine and either perform to a reset or return to an application default state.

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11.4.5.2 Overrun Condition (OVR)

An overrun condition occurs, when the master device has sent a data byte and the slave device has not cleared the SPIF bit issued from the previously transmitted byte.

When an Overrun occurs: – The OVR bit is set and an interrupt request is

generated if the SPIE bit is set.

In this case, the receiver buffer contains the byte sent after the SPIF bit was last cleared. A read to the SPIDR register returns this byte. All other bytes are lost.

The OVR bit is cleared by reading the SPICSR register.

11.4.5.3 Write Collision Error (WCOL)

A write collision occurs when the software tries to write to the SPIDR register while a data transfer is taking place with an external device. When this happens, the transfer continues uninterrupted; and the software write will be unsuccessful.

Write collisions can occur both in master and slave mode. See also Section 11.4.3.2 Slave Select

Management.

Note: a "read collision" will never occur since the received data byte is placed in a buffer in which access is always synchronous with the CPU operation.

The WCOL bit in the SPICSR register is set if a write collision occurs.

No SPI interrupt is generated when the WCOL bit is set (the WCOL bit is a status flag only).

Clearing the WCOL bit is done through a software sequence (see Figure 47).

Figure 47. Clearing the WCOL bit (Write Collision Flag) Software Sequence

Clearing sequence after SPIF = 1 (end of a data byte transfer)

1st Step

2nd Step

Read SPICSR

Read SPIDR

RESULT

SPIF =0 WCOL=0

Clearing sequence before SPIF = 1 (during a data byte transfer)

1st Step

2nd Step

Read SPICSR

Read SPIDR

RESULT

WCOL=0

Note: Writing to the SPIDR register instead of reading it does not reset the WCOL bit

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ST7LITE2

SERIAL PERIPHERAL INTERFACE (Cont’d)

11.4.5.4 Single Master and Multimaster Configurations

There are two types of SPI systems: – Single Master System – Multimaster System

Single Master System

A typical single master system may be configured, using a slaves (see Figure 48).

The master device selects the individual slave devices by using four pins of a parallel port to control the four SS

The SS master device ports will be forced to be inputs at that time, thus disabling the slave devices.

Note: To prevent a bus conflict on the MISO line the master allows only one active slave device during a transmission.

Figure 48. Single Master / Multiple Slave Configuration

device as the master and four devices as

pins of the slave devices.

pins are pulled high during reset since the

For more security, the slave device may respond to the master with the received data byte. Then the master will receive the previous byte back from the slave device if all MISO and MOSI pins are connected and the slave has not written to its SPIDR register.

Other transmission security methods can use ports for handshake lines or data bytes with command fields.

Multi-Master System

A multi-master system may also be configured by the user. Transfer of master control could be implemented using a handshake method through the I/O ports or by an exchange of code messages through the serial peripheral interface system.

The multi-master system is principally handled by the MSTR bit in the SPICR register and the MODF bit in the SPICSR register.

SCK

Device

MOSI

SCK

Master

Device

Slave

MISO

Ports

SCK

MOSI MOSI MOSIMISO MISO MISOMISO

Slave

Device

SCK

Slave

Device

SCK

Slave

Device

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SERIAL PERIPHERAL INTERFACE (Cont’d)

11.4.6 Low Power Modes

Mode Description

WAIT

HALT

No effect on SPI. SPI interrupt events cause the Device to exit from WAIT mode.

SPI registers are frozen. In HALT mode, the SPI is inactive. SPI operation resumes when the Device is woken up by an interrupt with “exit from HALT mode” capability. The data received is subsequently read from the SPIDR register when the software is running (interrupt vector fetching). If several data are received before the wakeup event, then an overrun error is generated. This error can be detected after the fetch of the interrupt routine that woke up the Device.

11.4.6.1 Using the SPI to wake-up the Device from Halt mode

In slave configuration, the SPI is able to wake-up the Device from HALT mode through a SPIF interrupt. The data received is subsequently read from the SPIDR register when the software is running (interrupt vector fetch). If multiple data transfers have been performed before software clears the SPIF bit, then the OVR bit is set by hardware.

Note: When waking up from Halt mode, if the SPI remains in Slave mode, it is recommended to perform an extra communications cycle to bring the SPI from Halt mode state to normal state. If the SPI exits from Slave mode, it returns to normal state immediately.

Caution: The SPI can wake-up the

Device from

Halt mode only if the Slave Select signal (external

ST7LITE2

pin or the SSI bit in the SPICSR register) is low

SS when the lection is configured as external (see Section

11.4.3.2), make sure the master drives a low level

on the SS

11.4.7 Interrupts

Interrupt Event

SPI End of Transfer Event

Master Mode Fault Event

Overrun Error OVR Yes No

Note: The SPI interrupt events are connected to the same interrupt vector (see Interrupts chapter). They generate an interrupt if the corresponding Enable Control Bit is set and the interrupt mask in the CC register is reset (RIM instruction).

Device enters Halt mode. So if Slave se-

pin when the slave enters Halt mode.

Event

Flag

SPIF

MODF Yes No

Enable

Control

Bit

SPIE

Exit from Wait

Yes Yes

Exit

from

Halt

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ST7LITE2

SERIAL PERIPHERAL INTERFACE (Cont’d)

11.4.8 Register Description CONTROL REGISTER (SPICR)

Read/Write Reset Value: 0000 xxxx (0xh)

SPIE SPE SPR2 MSTR CPOL CPHA SPR1 SPR0

Bit 7 = SPIE Serial Peripheral Interrupt Enable. This bit is set and cleared by software. 0: Interrupt is inhibited 1: An SPI interrupt is generated whenever an End

of Transfer event, Master Mode Fault or Overrun error occurs (SPIF=1, MODF=1 or OVR=1 in the SPICSR register)

Bit 6 = SPE Serial Peripheral Output Enable. This bit is set and cleared by software. It is also cleared by hardware when, in master mode, SS

=0 (see Section 11.4.5.1 Master Mode Fault

(MODF)). The SPE bit is cleared by reset, so the

SPI peripheral is not initially connected to the external pins. 0: I/O pins free for general purpose I/O 1: SPI I/O pin alternate functions enabled

Bit 5 = SPR2 Divider Enable. This bit is set and cleared by software and is cleared by reset. It is used with the SPR[1:0] bits to set the baud rate. Refer to Table 16 SPI Master

mode SCK Frequency.

0: Divider by 2 enabled 1: Divider by 2 disabled

Note: This bit has no effect in slave mode.

Bit 4 = MSTR Master Mode. This bit is set and cleared by software. It is also cleared by hardware when, in master mode, SS

=0 (see Section 11.4.5.1 Master Mode Fault

(MODF)).

0: Slave mode 1: Master mode. The function of the SCK pin

changes from an input to an output and the functions of the MISO and MOSI pins are reversed.

Bit 3 = CPOL Clock Polarity. This bit is set and cleared by software. This bit determines the idle state of the serial Clock. The CPOL bit affects both the master and slave modes. 0: SCK pin has a low level idle state 1: SCK pin has a high level idle state

Note: If CPOL is changed at the communication byte boundaries, the SPI must be disabled by resetting the SPE bit.

Bit 2 = CPHA Clock Phase. This bit is set and cleared by software. 0: The first clock transition is the first data capture

edge.

1: The second clock transition is the first capture

edge.

Note: The slave must have the same CPOL and CPHA settings as the master.

Bits 1:0 = SPR[1:0] Serial Clock Frequency. These bits are set and cleared by software. Used with the SPR2 bit, they select the baud rate of the SPI serial clock SCK output by the SPI in master mode.

Note: These 2 bits have no effect in slave mode.

Table 16. SPI Master mode SCK Frequency

Serial Clock SPR2 SPR1 SPR0

/4 1 0 0

CPU

/8 0 0 0

CPU

/16 0 0 1

CPU

/32 1 1 0

CPU

/64 0 1 0

CPU

/128 0 1 1

CPU

78/133

SERIAL PERIPHERAL INTERFACE (Cont’d) CONTROL/STATUS REGISTER (SPICSR)

Read/Write (some bits Read Only) Reset Value: 0000 0000 (00h)

Bit 2 = SOD SPI Output Disable. This bit is set and cleared by software. When set, it disables the alternate function of the SPI output (MOSI in master mode / MISO in slave mode)

SPIF WCOL OVR MODF - SOD SSM SSI

0: SPI output enabled (if SPE=1) 1: SPI output disabled

ST7LITE2

Bit 7 = SPIF Serial Peripheral Data Transfer Flag

(Read only).

This bit is set by hardware when a transfer has been completed. An interrupt is generated if SPIE=1 in the SPICR register. It is cleared by a software sequence (an access to the SPICSR register followed by a write or a read to the SPIDR register).

0: Data transfer is in progress or the flag has been

cleared.

1: Data transfer between the

Device and an exter-

nal device has been completed.

Note: While the SPIF bit is set, all writes to the SPIDR register are inhibited until the SPICSR register is read.

Bit 6 = WCOL Write Collision status (Read only). This bit is set by hardware when a write to the SPIDR register is done during a transmit sequence. It is cleared by a software sequence (see

Figure 47).

0: No write collision occurred 1: A write collision has been detected

Bit 5 = OVR SPI Overrun error (Read only). This bit is set by hardware when the byte currently being received in the shift register is ready to be transferred into the SPIDR register while SPIF = 1 (See Section 11.4.5.2). An interrupt is generated if SPIE = 1 in the SPICR register. The OVR bit is cleared by software reading the SPICSR register. 0: No overrun error 1: Overrun error detected

Bit 4 = MODF Mode Fault flag (Read only). This bit is set by hardware when the SS

pin is pulled low in master mode (see Section 11.4.5.1

Master Mode Fault (MODF)). An SPI interrupt can

be generated if SPIE=1 in the SPICR register. This bit is cleared by a software sequence (An access to the SPICSR register while MODF=1 followed by a write to the SPICR register). 0: No master mode fault detected 1: A fault in master mode has been detected

Bit 3 = Reserved, must be kept cleared.

Bit 1 = SSM SS

Management.

This bit is set and cleared by software. When set, it disables the alternate function of the SPI SS

and uses the SSI bit value instead. See Section

11.4.3.2 Slave Select Management.

0: Hardware management (SS

managed by exter-

nal pin)

1: Software management (internal SS

trolled by SSI bit. External SS

signal con-

pin free for gener-

al-purpose I/O)

Bit 0 = SSI SS

Internal Mode.

This bit is set and cleared by software. It acts as a ‘chip select’ by controlling the level of the SS

slave select signal when the SSM bit is set. 0 : Slave selected 1 : Slave deselected

DATA I/O REGISTER (SPIDR)

Read/Write Reset Value: Undefined

D7 D6 D5 D4 D3 D2 D1 D0

The SPIDR register is used to transmit and receive data on the serial bus. In a master device, a write to this register will initiate transmission/reception of another byte.

Notes: During the last clock cycle the SPIF bit is set, a copy of the received data byte in the shift register is moved to a buffer. When the user reads the serial peripheral data I/O register, the buffer is actually being read.

While the SPIF bit is set, all writes to the SPIDR register are inhibited until the SPICSR register is read.

Warning: A write to the SPIDR register places data directly into the shift register for transmission.

A read to the SPIDR register returns the value located in the buffer and not the content of the shift register (see Figure 42).

79/133

ST7LITE2

Table 17. SPI Register Map and Reset Values

Address

(Hex.)

0031h

0032h

0033h

Label

SPIDR

Reset Value

SPICR

Reset Value

SPICSR

Reset Value

76543210

MSB

xxxxxxx

SPIE

SPIF

SPE

WCOL

SPR20MSTR

OVR

MODF

CPOLxCPHA

SOD

SPR1

SSM

LSB

SPR0

SSI

80/133

11.5 10-BIT A/D CONVERTER (ADC)

ST7LITE2

11.5.1 Introduction

The on-chip Analog to Digital Converter (ADC) peripheral is a 10-bit, successive approximation converter with internal sample and hold circuitry. This peripheral has up to 7 multiplexed analog input channels (refer to device pin out description) that allow the peripheral to convert the analog voltage levels from up to 7 different sources.

The result of the conversion is stored in a 10-bit Data Register. The A/D converter is controlled through a Control/Status Register.

11.5.2 Main Features

■ 10-bit conversion

■ Up to 7 channels with multiplexed input

■ Linear successive approximation

Figure 49. ADC Block Diagram

CPU

DIV 2

DIV 4

■ Data register (DR) which contains the results

■ Conversion complete status flag

■ On/off bit (to reduce consumption)

The block diagram is shown in Figure 49.

11.5.3 Functional Description

11.5.3.1 Analog Power Supply

DDA

and V

are the high and low level refer-

SSA

ence voltage pins. In some devices (refer to device pin out description) they are internally connected to the V

and VSS pins.

Conversion accuracy may therefore be impacted by voltage drops and noise in the event of heavily loaded or badly decoupled power supply lines.

SLOW

bit

ADC

AIN0

AIN1

AINx

ANALOG

MUX

x 1 or x 8

AMPSEL

bit

ADCDRH

CH2 CH1EOC SPEED ADON 0 CH0

HOLD CONTROL

ADC

ADCCSR

ADC

ADCDRL 00 0

ANALOG TO DIGITAL

CONVERTER

D4 D3D5D9 D8 D7 D6 D2

AMP

CAL

SLOW

AMP

SEL

D1 D0

81/133

ST7LITE2

10-BIT A/D CONVERTER (ADC) (Cont’d)

11.5.3.2 Input Voltage Amplifier

The input voltage can be amplified by a factor of 8 by enabling the AMPSEL bit in the ADCDRL register.

When the amplifier is enabled, the input range is 0V to V

For example, if V vert voltages in the range 0V to 430mV with an ideal resolution of 0.6mV (equivalent to 13-bit resolution with reference to a V

For more details, refer to the Electrical characteristics section.

Note: The amplifier is switched on by the ADON bit in the ADCCSR register, so no additional startup time is required when the amplifier is selected by the AMPSEL bit.

11.5.3.3 Digital A/D Conversion Result

The conversion is monotonic, meaning that the result never decreases if the analog input does not and never increases if the analog input does not.

If the input voltage (V (high-level voltage reference) then the conversion result is FFh in the ADCDRH register and 03h in the ADCDRL register (without overflow indication).

If the input voltage (V level voltage reference) then the conversion result in the ADCDRH and ADCDRL registers is 00 00h.

The A/D converter is linear and the digital result of the conversion is stored in the ADCDRH and ADCDRL registers. The accuracy of the conversion is described in the Electrical Characteristics Section.

AIN

for an analog input signal. If the impedance is too high, this will result in a loss of accuracy due to leakage and sampling not being completed in the alloted time.

11.5.3.4 A/D Conversion

The analog input ports must be configured as input, no pull-up, no interrupt. Refer to the «I/O ports» chapter. Using these pins as analog inputs does not affect the ability of the port to be read as a logic input.

/8.

= 5V, then the ADC can con-

to VDD range).

) is greater than V

AIN

) is lower than V

AIN

SSA

DDA

(low-

is the maximum recommended impedance

In the ADCCSR register:

– Select the CS[2:0] bits to assign the analog

channel to convert.

ADC Conversion mode

In the ADCCSR register: Set the ADON bit to enable the A/D converter and

to start the conversion. From this time on, the ADC performs a continuous conversion of the selected channel.

When a conversion is complete:

– The EOC bit is set by hardware. – The result is in the ADCDR registers.

A read to the ADCDRH resets the EOC bit. To read the 10 bits, perform the following steps:

1. Poll EOC bit

2. Read ADCDRL

3. Read ADCDRH. This clears EOC automati-

cally.

To read only 8 bits, perform the following steps:

1. Poll EOC bit

2. Read ADCDRH. This clears EOC automati-

cally.

11.5.4 Low Power Modes Note: The A/D converter may be disabled by re-

setting the ADON bit. This feature allows reduced power consumption when no conversion is needed and between single shot conversions.

Mode Description

WAIT No effect on A/D Converter

A/D Converter disabled. After wakeup from Halt mode, the A/D

HALT

Converter requires a stabilization time

(see Electrical Characteristics)

STAB

before accurate conversions can be performed.

11.5.5 Interrupts

None.

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10-BIT A/D CONVERTER (ADC) (Cont’d)

11.5.6 Register Description

ST7LITE2

CONTROL/STATUS REGISTER (ADCCSR)

Read/Write (Except bit 7 read only) Reset Value: 0000 0000 (00h)

EOC SPEED ADON 0 CH3 CH2 CH1 CH0

DATA REGISTER HIGH (ADCDRH)

Read Only Reset Value: xxxx xxxx (xxh)

D9 D8 D7 D6 D5 D4 D3 D2

Bit 7 = EOC End of Conversion This bit is set by hardware. It is cleared by software reading the ADCDRH register. 0: Conversion is not complete 1: Conversion complete

Bits 7:0 = D[9:2] MSB of Analog Converted Value

AMP CONTROL/DATA REGISTER LOW (ADCDRL)

Read/Write

Bit 6 = SPEED ADC clock selection

Reset Value: 0000 00xx (0xh)

This bit is set and cleared by software. It is used together with the SLOW bit to configure the ADC

clock speed. Refer to the table in the SLOW bit description.

Bit 5 = ADON A/D Converter on

000

Bits 7:5 = Reserved. Forced by hardware to 0.

AMP CAL

SLOW

This bit is set and cleared by software. 0: A/D converter and amplifier are switched off 1: A/D converter and amplifier are switched on

Bit 4 = AMPCAL Amplifier Calibration Bit This bit is set and cleared by software. User is suggested to use this bit to calibrate the ADC when

Bits 4:3 = Reserved. Must be kept cleared.

amplifier is ON. Setting this bit internally connects amplifier input to 0v. Hence, corresponding ADC output can be used in software to eliminate ampli-

Bits 2:0 = CH[2:0] Channel Selection These bits are set and cleared by software. They select the analog input to convert.

Channel Pin* CH2 CH1 CH0

AIN0 0 0 0 AIN1 0 0 1 AIN2 0 1 0 AIN3 0 1 1 AIN4 1 0 0 AIN5 1 0 1 AIN6 1 1 0

*The number of channels is device dependent. Refer to the device pinout description.

fier-offset error. 0: Calibration off 1: Calibration on (The input voltage of the amp is set to 0V)

Note: It is advised to use this bit to calibrate the ADC when the amplifier is ON. Setting this bit internally connects the amplifier input to 0v. Hence, the corresponding ADC output can be used in software to eliminate an amplifier-offset error.

Bit 3 = SLOW Slow mode This bit is set and cleared by software. It is used together with the SPEED bit to configure the ADC clock speed as shown on the table below.

AMP-

SEL

D1 D0

ADC

/2 00

CPU

/4 1x

CPU

SLOW SPEED

This bit is set and cleared by software.

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Bit 2 = AMPSEL Amplifier Selection Bit 0: Amplifier is not selected 1: Amplifier is selected

Bits 1:0 = D[1:0] LSB of Analog Converted Value Note: When AMPSEL=1 it is mandatory that f

be less than or equal to 2 MHz.

Table 18. ADC Register Map and Reset Values

ADC

Address

(Hex.)

0034h

0035h

0036h

Label

ADCCSR

Reset Value

ADCDRH

Reset Value

ADCDRL

Reset Value

76543210

EOC0SPEED0ADON

0 0

AMPCAL0SLOW0AMPSEL0D1

0 0

CH2

CH1

CH0

84/133

12 INSTRUCTION SET

ST7LITE2

12.1 ST7 ADDRESSING MODES

The ST7 Core features 17 different addressing modes which can be classified in seven main groups:

Addressing Mode Example

Inherent nop Immediate ld A,#$55 Direct ld A,$55 Indexed ld A,($55,X) Indirect ld A,([$55],X) Relative jrne loop Bit operation bset byte,#5

The ST7 Instruction set is designed to minimize the number of bytes required per instruction: To do so, most of the addressing modes may be subdivided in two submodes called long and short:

– Long addressing mode is more powerful be-

cause it can use the full 64 Kbyte address space, however it uses more bytes and more CPU cycles.

– Short addressing mode is less powerful because

it can generally only access page zero (0000h 00FFh range), but the instruction size is more compact, and faster. All memory to memory instructions use short addressing modes only (CLR, CPL, NEG, BSET, BRES, BTJT, BTJF, INC, DEC, RLC, RRC, SLL, SRL, SRA, SWAP)

The ST7 Assembler optimizes the use of long and short addressing modes.

Table 19. ST7 Addressing Mode Overview

Mode Syntax

Inherent nop + 0 Immediate ld A,#$55 + 1 Short Direct ld A,$10 00..FF + 1 Long Direct ld A,$1000 0000..FFFF + 2

No Offset Direct Indexed ld A,(X) 00..FF

Short Direct Indexed ld A,($10,X) 00..1FE + 1 Long Direct Indexed ld A,($1000,X) 0000..FFFF + 2 Short Indirect ld A,[$10] 00..FF 00..FF byte + 2 Long Indirect ld A,[$10.w] 0000..FFFF 00..FF word + 2 Short Indirect Indexed ld A,([$10],X) 00..1FE 00..FF byte + 2 Long Indirect Indexed ld A,([$10.w],X) 0000..FFFF 00..FF word + 2 Relative Direct jrne loop PC-128/PC+127 Relative Indirect jrne [$10] PC-128/PC+127 Bit Direct bset $10,#7 00..FF + 1 Bit Indirect bset [$10],#7 00..FF 00..FF byte + 2 Bit Direct Relative btjt $10,#7,skip 00..FF + 2 Bit Indirect Relative btjt [$10],#7,skip 00..FF 00..FF byte + 3

Note:

1. At the time the instruction is executed, the Program Counter (PC) points to the instruction following JRxx.

Destination/

Source

Pointer

Address

(Hex.)

00..FF byte + 2

Pointer

Size

(Hex.)

Length (Bytes)

+ 0 (with X register) + 1 (with Y register)

+ 1

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ST7LITE2

ST7 ADDRESSING MODES (Cont’d)

12.1.1 Inherent

All Inherent instructions consist of a single byte. The opcode fully specifies all the required information for the CPU to process the operation.

Inherent Instruction Function

NOP No operation TRAP S/W Interrupt

WFI

HALT

RET Subroutine Return IRET Interrupt Subroutine Return SIM Set Interrupt Mask RIM Reset Interrupt Mask SCF Set Carry Flag RCF Reset Carry Flag RSP Reset Stack Pointer LD Load CLR Clear PUSH/POP Push/Pop to/from the stack INC/DEC Increment/Decrement TNZ Test Negative or Zero CPL, NEG 1 or 2 Complement MUL Byte Multiplication SLL, SRL, SRA, RLC,

RRC SWAP Swap Nibbles

Wait For Interrupt (Low Power Mode)

Halt Oscillator (Lowest Power Mode)

Shift and Rotate Operations

12.1.3 Direct

In Direct instructions, the operands are referenced by their memory address.

The direct addressing mode consists of two submodes:

Direct (short)

The address is a byte, thus requires only 1 byte after the opcode, but only allows 00 - FF addressing space.

Direct (long)

The address is a word, thus allowing 64 Kbyte addressing space, but requires 2 bytes after the opcode.

12.1.4 Indexed (No Offset, Short, Long)

In this mode, the operand is referenced by its memory address, which is defined by the unsigned addition of an index register (X or Y) with an offset.

The indirect addressing mode consists of three submodes:

Indexed (No Offset)

There is no offset (no extra byte after the opcode), and allows 00 - FF addressing space.

Indexed (Short)

The offset is a byte, thus requires only 1 byte after the opcode and allows 00 - 1FE addressing space.

Indexed (long)

The offset is a word, thus allowing 64 Kbyte addressing space and requires 2 bytes after the opcode.

12.1.2 Immediate

Immediate instructions have 2 bytes, the first byte contains the opcode, the second byte contains the operand value.

Immediate Instruction Function

LD Load CP Compare BCP Bit Compare AND, OR, XOR Logical Operations ADC, ADD, SUB, SBC Arithmetic Operations

86/133

12.1.5 Indirect (Short, Long)

The required data byte to do the operation is found by its memory address, located in memory (pointer).

The pointer address follows the opcode. The indirect addressing mode consists of two submodes:

Indirect (short)

The pointer address is a byte, the pointer size is a byte, thus allowing 00 - FF addressing space, and requires 1 byte after the opcode.

Indirect (long)

The pointer address is a byte, the pointer size is a word, thus allowing 64 Kbyte addressing space, and requires 1 byte after the opcode.

ST7 ADDRESSING MODES (Cont’d)

12.1.6 Indirect Indexed (Short, Long)

This is a combination of indirect and short indexed addressing modes. The operand is referenced by its memory address, which is defined by the unsigned addition of an index register value (X or Y) with a pointer value located in memory. The pointer address follows the opcode.

The indirect indexed addressing mode consists of two submodes:

Indirect Indexed (Short)

The pointer address is a byte, the pointer size is a byte, thus allowing 00 - 1FE addressing space, and requires 1 byte after the opcode.

Indirect Indexed (Long)

The pointer address is a byte, the pointer size is a word, thus allowing 64 Kbyte addressing space, and requires 1 byte after the opcode.

Table 20. Instructions Supporting Direct, Indexed, Indirect and Indirect Indexed Addressing Modes

ST7LITE2

12.1.7 Relative Mode (Direct, Indirect)

This addressing mode is used to modify the PC register value by adding an 8-bit signed offset to it.

Available Relative Direct/

Indirect Instructions

JRxx Conditional Jump CALLR Call Relative

The relative addressing mode consists of two submodes:

Relative (Direct)

The offset follows the opcode.

Relative (Indirect)

The offset is defined in memory, of which the address follows the opcode.

Function

Long and Short

Instructions

LD Load CP Compare AND, OR, XOR Logical Operations

ADC, ADD, SUB, SBC

BCP Bit Compare

Short Instructions Only Function

CLR Clear INC, DEC Increment/Decrement TNZ Test Negative or Zero CPL, NEG 1 or 2 Complement BSET, BRES Bit Operations

BTJT, BTJF

SLL, SRL, SRA, RLC, RRC

SWAP Swap Nibbles CALL, JP Call or Jump subroutine

Arithmetic Addition/subtraction operations

Bit Test and Jump Operations

Shift and Rotate Operations

Function

87/133

ST7LITE2

12.2 INSTRUCTION GROUPS

The ST7 family devices use an Instruction Set consisting of 63 instructions. The instructions may

Load and Transfer LD CLR Stack operation PUSH POP RSP Increment/Decrement INC DEC Compare and Tests CP TNZ BCP Logical operations AND OR XOR CPL NEG Bit Operation BSET BRES Conditional Bit Test and Branch BTJT BTJF Arithmetic operations ADC ADD SUB SBC MUL Shift and Rotates SLL SRL SRA RLC RRC SWAP SLA Unconditional Jump or Call JRA JRT JRF JP CALL CALLR NOP RET Conditional Branch JRxx Interruption management TRAP WFI HALT IRET Condition Code Flag modification SIM RIM SCF RCF

Using a prebyte

The instructions are described with 1 to 4 bytes. In order to extend the number of available op-

codes for an 8-bit CPU (256 opcodes), three different prebyte opcodes are defined. These prebytes modify the meaning of the instruction they precede.

The whole instruction becomes:

PC-2 End of previous instruction PC-1 Prebyte PC Opcode PC+1 Additional word (0 to 2) according to the

number of bytes required to compute the effective address

be subdivided into 13 main groups as illustrated in the following table:

PDY 90 Replace an X based instruction using

immediate, direct, indexed, or inherent addressing mode by a Y one.

PIX 92 Replace an instruction using direct, di-

rect bit or direct relative addressing mode to an instruction using the corresponding indirect addressing mode. It also changes an instruction using X indexed addressing mode to an instruction using indirect X indexed addressing mode.

PIY 91 Replace an instruction using X indirect

indexed addressing mode by a Y one.

12.2.1 Illegal Opcode Reset

In order to provide enhanced robustness to the device against unexpected behavior, a system of illegal opcode detection is implemented. If a code to

These prebytes enable instruction in Y as well as indirect addressing modes to be implemented. They precede the opcode of the instruction in X or the instruction using direct addressing mode. The prebytes are:

be executed does not correspond to any opcode or prebyte value, a reset is generated. This, combined with the Watchdog, allows the detection and recovery from an unexpected fault or interference.

Note: A valid prebyte associated with a valid opcode forming an unauthorized combination does not generate a reset.

88/133

ST7LITE2

INSTRUCTION GROUPS (Cont’d)

Mnemo Description Function/Example Dst Src H I N Z C

ADC Add with Carry A = A + M + C A M H N Z C ADD Addition A = A + M A M H N Z C AND Logical And A = A . M A M N Z BCP Bit compare A, Memory tst (A . M) A M N Z BRES Bit Reset bres Byte, #3 M BSET Bit Set bset Byte, #3 M BTJF Jump if bit is false (0) btjf Byte, #3, Jmp1 M C BTJT Jump if bit is true (1) btjt Byte, #3, Jmp1 M C CALL Call subroutine CALLR Call subroutine relative CLR Clear reg, M 0 1 CP Arithmetic Compare tst(Reg - M) reg M N Z C CPL One Complement A = FFH-A reg, M N Z 1 DEC Decrement dec Y reg, M N Z HALT Halt 0 IRET Interrupt routine return Pop CC, A, X, PC H I N Z C INC Increment inc X reg, M N Z JP Absolute Jump jp [TBL.w] JRA Jump relative always JRT Jump relative JRF Never jump jrf * JRIH Jump if ext. interrupt = 1 JRIL Jump if ext. interrupt = 0 JRH Jump if H = 1 H = 1 ? JRNH Jump if H = 0 H = 0 ? JRM Jump if I = 1 I = 1 ? JRNM Jump if I = 0 I = 0 ? JRMI Jump if N = 1 (minus) N = 1 ? JRPL Jump if N = 0 (plus) N = 0 ? JREQ Jump if Z = 1 (equal) Z = 1 ? JRNE Jump if Z = 0 (not equal) Z = 0 ? JRC Jump if C = 1 C = 1 ? JRNC Jump if C = 0 C = 0 ? JRULT Jump if C = 1 Unsigned < JRUGE Jump if C = 0 Jmp if unsigned >= JRUGT Jump if (C + Z = 0) Unsigned >

89/133

ST7LITE2

INSTRUCTION GROUPS (Cont’d)

Mnemo Description Function/Example Dst Src H I N Z C

JRULE Jump if (C + Z = 1) Unsigned <=

LD Load dst <= src reg, M M, reg N Z

MUL Multiply X,A = X * A A, X, Y X, Y, A 0 0

NEG Negate (2's compl) neg $10 reg, M N Z C

NOP No Operation

OR OR operation A = A + M A M N Z

POP Pop from the Stack pop reg reg M

pop CC CC M H I N Z C

PUSH Push onto the Stack push Y M reg, CC

RCF Reset carry flag C = 0 0

RET Subroutine Return

RIM Enable Interrupts I = 0 0

RLC Rotate left true C C <= Dst <= C reg, M N Z C

RRC Rotate right true C C => Dst => C reg, M N Z C

RSP Reset Stack Pointer S = Max allowed

SBC Subtract with Carry A = A - M - C A M N Z C

SCF Set carry flag C = 1 1

SIM Disable Interrupts I = 1 1

SLA Shift left Arithmetic C <= Dst <= 0 reg, M N Z C

SLL Shift left Logic C <= Dst <= 0 reg, M N Z C

SRL Shift right Logic 0 => Dst => C reg, M 0 Z C

SRA Shift right Arithmetic Dst7 => Dst => C reg, M N Z C

SUB Subtraction A = A - M A M N Z C

SWAP SWAP nibbles Dst[7..4] <=> Dst[3..0] reg, M N Z

TNZ Test for Neg & Zero tnz lbl1 N Z

TRAP S/W trap S/W interrupt 1

WFI Wait for Interrupt 0

XOR Exclusive OR A = A XOR M A M N Z

90/133

13 ELECTRICAL CHARACTERISTICS

13.1 PARAMETER CONDITIONS

ST7LITE2

Unless otherwise specified, all voltages are referred to V

13.1.1 Minimum and Maximum values

Unless otherwise specified the minimum and maximum values are guaranteed in the worst conditions of ambient temperature, supply voltage and frequencies by tests in production on 100% of the devices with an ambient temperature at T and T

max (given by the selected temperature

A=TA

=25°C

range). Data based on characterization results, design

simulation and/or technology characteristics are indicated in the table footnotes and are not tested in production. Based on characterization, the minimum and maximum values refer to sample tests and represent the mean value plus or minus three times the standard deviation (mean±3Σ).

13.1.2 Typical values

Unless otherwise specified, typical data are based

=25°C, VDD=5V (for the 4.5V≤VDD≤5.5V

on T

voltage range) and V

=3.3V (for the 3V≤VDD≤4V

voltage range). They are given only as design guidelines and are not tested.

13.1.3 Typical curves

Unless otherwise specified, all typical curves are given only as design guidelines and are not tested.

13.1.4 Loading capacitor

The loading conditions used for pin parameter measurement are shown in Figure 50.

13.1.5 Pin input voltage

The input voltage measurement on a pin of the device is described in Figure 51.

Figure 51. Pin input voltage

ST7 PIN

Figure 50. Pin loading conditions

ST7 PIN

91/133

ST7LITE2

13.2 ABSOLUTE MAXIMUM RATINGS

Stresses above those listed as “absolute maximum ratings” may cause permanent damage to the device. This is a stress rating only and functional operation of the device under these condi-

13.2.1 Voltage Characteristics

Symbol Ratings Maximum value Unit

- V

ESD(HBM)

Supply voltage 7.0 Input voltage on any pin

1) & 2)

Electrostatic discharge voltage (Human Body Model)

13.2.2 Current Characteristics

Symbol Ratings Maximum value Unit

VDD

VSS

Total current into VDD power lines (source) Total current out of VSS ground lines (sink) Output current sunk by any standard I/O and control pin 25

Output current sunk by any high sink I/O pin 50 Output current source by any I/Os and control pin - 25 Injected current on RESET pin ± 5

INJ(PIN)

2) & 4)

Injected current on OSC1 and OSC2 pins ± 5 Injected current on PB0 and PB1 pins Injected current on any other pin

ΣI

INJ(PIN)

Total injected current (sum of all I/O and control pins)

13.2.3 Thermal Characteristics

tions is not implied. Exposure to maximum rating conditions for extended periods may affect device reliability.

VSS-0.3 to VDD+0.3

see section 13.7.3 on

page 105

100 100

± 5

± 20

Symbol Ratings Value Unit

STG

Storage temperature range -65 to +150 °C Maximum junction temperature (see Table 21, “THERMAL CHARACTERISTICS,” on

page 120)

Notes:

1. Directly connecting the I/O pins to V

tion occurs (for example, due to a corrupted program counter). To guarantee safe operation, this connection has to be done through a pull-up or pull-down resistor (typical: 10kΩ for I/Os). Unused I/O pins must be tied in the same way to V or VSS according to their reset configuration.

2. I respected, the injection current must be limited externally to the I

must never be exceeded. This is implicitly insured if VIN maximum is respected. If VIN maximum cannot be

INJ(PIN)

while a negative injection is induced by VIN<VSS. For true open-drain pads, there is no positive injection current, and the corresponding V

3. All power (V

4. Negative injection disturbs the analog performance of the device. In particular, it induces leakage currents throughout

maximum must always be respected

) and ground (VSS) lines must always be connected to the external supply.

or V

could damage the device if an unexpected change of the I/O configura-

value. A positive injection is induced by VIN>V

INJ(PIN)

the device including the analog inputs. To avoid undesirable effects on the analog functions, care must be taken:

- Analog input pins must have a negative injection less than 0.8 mA (assuming that the impedance of the analog voltage is lower than the specified limits)

- Pure digital pins must have a negative injection less than 1.6mA. In addition, it is recommended to inject the current as far as possible from the analog input pins.

5. No negative current injection allowed on PB0 and PB1 pins.

6. When several inputs are submitted to a current injection, the maximum ΣI

and negative injected currents (instantaneous values). These results are based on characterisation with ΣI mum current injection on four I/O port pins of the device.

is the absolute sum of the positive

INJ(PIN)

maxi-

92/133

ST7LITE2

13.3 OPERATING CONDITIONS

13.3.1 General operating conditions

= -40 to +85°C unless otherwise specified.

Symbol Parameter Conditions Min Max Unit

= 4 MHz. max., 2.4 5.5

CPU

Supply voltage

CPU clock frequency

CPU

= 8 MHz. max. 3.3 5.5

CPU

3.3V≤ V

2.4V≤V

≤5.5V up to 8

<3.3V up to 4

MHz

Figure 52. f

FUNCTIONALITY

NOT GUARANTEED

CPU

IN THIS AREA

Maximum operating frequency versus V

[MHz]

CPU

2.0 2.4

2.7

3.3 3.5 4.0 4.5 5.0

supply voltage

FUNCTIONALITY GUARANTEED IN THIS AREA (UNLESS OTHERWISE STATED IN THE TABLES OF PARAMETRIC DATA)

SUPPLY VOLTAGE [V]

5.5

93/133

ST7LITE2

13.3.2 Operating conditions with Low Voltage Detector (LVD)

= -40 to 85°C, unless otherwise specified

Symbol Parameter Conditions Min Typ Max Unit

IT+

IT-

(LVD)

hys

POR

g(VDD)

DD(LVD

(LVD)

Reset release threshold

rise)

Reset generation threshold

fall)

LVD voltage threshold hysteresis V VDD rise time rate Filtered glitch delay on V

2)3)

) LVD/AVD current consumption 220 µA

High Threshold Med. Threshold Low Threshold

(LVD)

-V

IT-

(LVD)

IT+

Not detected by the LVD 150 ns

Notes:

1. Not tested in production.

2. Not tested in production. The V

When the V

slope is outside these values, the LVD may not ensure a proper reset of the MCU.

rise time rate condition is needed to insure a correct device power-on and LVD reset.

3. 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

page 112 and note 4.

down to 0V to ensure optimum restart conditions. Refer to circuit example in Figure 84 on

13.3.3 Auxiliary Voltage Detector (AVD) Thresholds

= -40 to 85°C, unless otherwise specified

Symbol Parameter Conditions Min Typ Max Unit

∆V

IT+

IT-

hys

(AVD)

IT-

1=>0 AVDF flag toggle threshold

rise)

0=>1 AVDF flag toggle threshold

fall)

AVD voltage threshold hysteresis V Voltage drop between AVD flag set

and LVD reset activation

Note:

1. Not tested in production.

High Threshold Med. Threshold Low Threshold

IT+

-V

(AVD)

IT-

(AVD)

fall 0.45 V

4.00

3.40

2.65

3.80

3.20

2.40

4.25

3.60

2.90

4.05

3.40

2.70

4.50

3.80

3.15

4.30

3.65

2.90

200 mV

20 20000 µs/V

4.40

3.90

3.20

4.30

3.70

2.90

4.70

4.10

3.40

4.60

3.90

3.20

5.00

4.30

3.60

4.90

4.10

3.40

150 mV

13.3.4 Internal RC Oscillator and PLL

The ST7 internal clock can be supplied by an internal RC oscillator and PLL (selectable by option byte).

Symbol Parameter Conditions Min Typ Max Unit

DD(RC)

DD(x4PLL)

DD(x8PLL)

Internal RC Oscillator operating voltage 2.4 5.5 x4 PLL operating voltage 2.4 3.3 x8 PLL operating voltage 3.3 5.5

PLL

input

STARTUP

PLL Startup time 60

clock

PLL

cycles

94/133

)

ST7LITE2

OPERATING CONDITIONS (Cont’d)

The RC oscillator and PLL characteristics are temperature-dependent and are grouped in four tables.

13.3.4.1 RC oscillator and PLL characteristics (tested for T

Symbol Parameter Conditions Min Typ Max Unit

ACC

DD(RC)

su(RC)

PLL

LOCK

STAB

ACC

w(JIT)

JIT

PLL

DD(PLL)

Internal RC oscillator frequency

Accuracy of Internal RC oscillator with

RCCR=RCCR0

RC oscillator current consumption

RC oscillator setup time TA=25°C, VDD=5V 10 x8 PLL input clock 1 PLL Lock time

PLL Stabilization time

x8 PLL Accuracy

PLL

PLL jitter period fRC = 1MHz 125 PLL jitter (∆f

CPU/fCPU

PLL current consumption TA=25°C 600

RCCR = FF (reset value), TA=25°C,VDD=5V 760 RCCR = RCCR0

3 )

, TA=25°C,VDD=5V 1000 TA=25°C, VDD=4.5 to 5.5V -1 +1% T

=-40 to +85°C, VDD=5V -5 +2 %

=0 to +85°C, VDD=4.5 to 5.5V -2

=25°C, VDD=5V 970

= 1MHz@TA=25°C, VDD=4.5 to 5.5V 0.1

= 1MHz@TA=-40 to +85°C, VDD=5V 0.1

= -40 to +85°C) @ VDD = 4.5 to 5.5V

2ms 4ms

kHz

µA

µs

MHz

% % µs %

µA

Notes:

1. If the RC oscillator clock is selected, to improve clock stability and frequency accuracy, it is recommended to place a

decoupling capacitor, typically 100nF, between the V

and VSS pins as close as possible to the ST7 device.

2. Data based on characterization results, not tested in production

3. See “INTERNAL RC OSCILLATOR ADJUSTMENT” on page 23

4. Guaranteed by design.

5. Averaged over a 4ms period. After the LOCKED bit is set, a period of t

6. After the LOCKED bit is set ACC

is max. 10% until t

PLL

has elapsed. See Figure 12 on page 24.

STAB

is required to reach ACC

STAB

accuracy.

PLL

95/133

ST7LITE2

OPERATING CONDITIONS (Cont’d)

13.3.4.2 RC oscillator and PLL characteristics (tested for T

Symbol Parameter Conditions Min Typ Max Unit

ACC

DD(RC)

su(RC)

PLL

LOCK

STAB

ACC

w(JIT)

JIT

PLL

DD(PLL)

Internal RC oscillator fre-

quency

Accuracy of Internal RC oscillator when calibrated

with RCCR=RCCR1

RC oscillator current consumption

RC oscillator setup time TA=25°C,VDD=3V 10 x4 PLL input clock 0.7 PLL Lock time

PLL Stabilization time

x4 PLL Accuracy

PLL

PLL jitter period fRC = 1MHz 125 PLL jitter (∆f

CPU/fCPU

PLL current consumption TA=25°C 190

RCCR = FF (reset value), TA=25°C, VDD= 3.0V 560 RCCR=RCCR1

,TA=25°C,VDD= 3V 700 TA=25°C,VDD=3V -2 +2 % T

=25°C,VDD=2.7 t 3.3V -25 +25 %

2)3)

=-40 to +85°C,VDD=3V -15 15 %

=25°C,VDD=3V 700

= 1MHz@TA=25°C,VDD=2.7 to 3.3V 0.1

= 1MHz@TA=40 to +85°C,VDD= 3V 0.1

= -40 to +85°C) @ VDD = 2.7 to 3.3V

2ms 4ms

kHz

µA

µs

MHz

% % µs %

µA

Notes:

1. If the RC oscillator clock is selected, to improve clock stability and frequency accuracy, it is recommended to place a

decoupling capacitor, typically 100nF, between the V

and VSS pins as close as possible to the ST7 device.

2. Data based on characterization results, not tested in production

3. See “INTERNAL RC OSCILLATOR ADJUSTMENT” on page 23.

4. Guaranteed by design.

5. Averaged over a 4ms period. After the LOCKED bit is set, a period of t

6. After the LOCKED bit is set ACC

is max. 10% until t

PLL

has elapsed. See Figure 12 on page 24.

STAB

is required to reach ACC

STAB

accuracy

PLL

96/133

OPERATING CONDITIONS (Cont’d)

)

ST7LITE2

Figure 53. RC Osc Freq vs V (Calibrated with RCCR1: 3V @ 25°C)

@ TA=25°C

1.00

0.90

0.80

0.70

0.60

Output Freq (MHz

0.50

2.4 2.6 2.8 3 3.2 3.4 3.6 3.8 4 VDD (V)

Figure 55. Typical RC oscillator Accuracy vs temperature @ V (Calibrated with RCCR0: 5V @ 25°C

2 1 0

-1

RC Accuracy

-2

-3

-4

(

)

-5

-45 025 85

) tested in production

(

=5V

Temperature (°C)

)

(

(*)

125

Figure 54. RC Osc Freq vs V (Calibrated with RCCR0: 5V@ 25°C)

1.10

1.00

0.90

0.80

0.70

0.60

0.50

0.40

0.30

Output Freq. (MHz)

0.20

0.10

0.00

2.533.544.555.56 Vdd (V)

Figure 56. RC Osc Freq vs V

1.80

1.60

1.40

1.20

1.00

0.80

0.60

Output Freq. (MHz)

0.40

0.20

0.00

2.4 2.7 3 3.3 3.75 4 4.5 5 5.5 6

Vdd (V)

and RCCR Value

-45° 0° 25° 90° 105° 130°

rccr=00h rccr=64h rccr=80h rccr=C0h rccr=FFh

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ST7LITE2

OPERATING CONDITIONS (Cont’d)

Figure 57. PLL ∆f

∆f

Max

Min

CPU/fCPU

versus time

Figure 58. PLLx4 Output vs CLKIN frequency

7.00

6.00

5.00

4.00

3.00

Output Frequency (MHz)

2.00

1.00

11.522.53

Ext ernal Input Clock Frequency (MHz )

3.3 3

2.7

w(JIT)

Figure 59. PLLx8 Output vs CLKIN frequency

11.00

9.00

7.00

5.00

3.00

Output Frequency (MHz)

1.00

0.85 0.9 1 1.5 2 2.5

External Input Cloc k Frequency (MHz)

5.5 5

4.5 4

Note: f

OSC

= f

CLKIN

/2*PLL4

13.3.4.3 32MHz PLL

= -40 to 85°C, unless otherwise specified

Symbol Parameter Min Typ Max Unit

PLL32

INPUT

Voltage Frequency Input Frequency

Note 1: 32 MHz is guaranteed within this voltage range.

98/133

Note: f

OSC

= f

CLKIN

/2*PLL8

4.5 5 5.5 V 32 MHz

89MHz

13.4 SUPPLY CURRENT CHARACTERISTICS

ST7LITE2

The following current consumption specified for the ST7 functional operating modes over temperature range does not take into account the clock

vice consumption, the two current values must be added (except for HALT mode for which the clock is stopped).

source current consumption. To get the total de-

13.4.1 Supply Current

= -40 to +85°C unless otherwise specified, V

Symbol Parameter Conditions Typ Max Unit

Supply current in RUN mode

Supply current in WAIT mode

Supply current in SLOW mode f Supply current in SLOW WAIT mode f

Supply current in HALT mode

Supply current in AWUFH mode

6)7)

Notes:

1. CPU running with memory access, all I/O pins in input mode with a static value at V

in reset state; clock input (CLKIN) driven by external square wave, LVD disabled.

2. All I/O pins in input mode with a static value at V driven by external square wave, LVD disabled.

3. SLOW mode selected with f (no load), all peripherals in reset state; clock input (CLKIN) driven by external square wave, LVD disabled.

4. SLOW-WAIT mode selected with f or VSS (no load), all peripherals in reset state; clock input (CLKIN) driven by external square wave, LVD disabled.

based on f

CPU

based on f

CPU

OSC

5. All I/O pins in output mode with a static value at V

tested in production at VDD max and f

CPU

max.

6. All I/O pins in input mode with a static value at V

max.

7. This consumption refers to the Halt period only and not the associated run period which is software dependent.

=5.5V

External Clock, f Internal RC, f f

CPU

=8MHz

External Clock, f Internal RC, f f

CPU

=8MHz =250kHz =250kHz

=1MHz

CPU

=1MHz 2.2

CPU

=1MHz

CPU

=1MHz 1.8

CPU

-40°C≤TA≤+85°C = +125°C

TA= +25°C

or VSS (no load), all peripherals in reset state; clock input (CLKIN)

7.5 12

0.8 mA

3.7 6

1.6 2.5

110 15 50

µAT

20 30

or VSS (no load), all peripherals

divided by 32. All I/O pins in input mode with a static value at VDD or

divided by 32. All I/O pins in input mode with a static value at

OSC

(no load), LVD disabled. Data based on characterization results,

or VSS (no load). Data tested in production at VDD max. and f

CPU

Figure 60. Typical IDD in RUN vs. f

9.0

8.0

7.0

6.0

5.0

4.0

Idd (mA)

3.0

2.0

1.0

0.0

2.02.53.03.54.04.55.05.56.0

8Mhz 4Mhz 1Mhz

Vdd (V)

CPU

Figure 61. Typical IDD in SLOW vs. f

1.6

1.4

1.2

1.0

0.8

0.6

Idd (mA)

0.4

0.2

0.0

250Khz 125Khz

62.5Hz

2 2.5 3 3.5 4 4.5 5 5.5 6

Vdd (V)

CPU

99/133

ST7LITE2

SUPPLY CURRENT CHARACTERISITCS (Cont’d)

Figure 62. Typical I

4.5

4.0

3.5

3.0

2.5

2.0

Idd (mA)

1.5

1.0

0.5

0.0

8Mhz 4Mhz 1MHz

2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0

in WAIT vs. f

Vdd (V)

CPU

Figure 63. Typical IDD in SLOW-WAIT vs. f

1.4

1.2

1.0

0.8

0.6

Idd (mA)

0.4

0.2

0.0

250KHz 125KHz

62.5Khz

TBD

2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0

Vdd (V)

CPU

Figure 64. Typical IDD in AWUFH mode at T

=25°C

0.035

0.030

0.025

0.020

0.015

Idd(mA)

0.010

0.005

0.000

Figure 65. Typical I at V

= 5V and f

8.0

7.0

6.0

5.0

Idd (mA)

4.0

fawu_rc ~125 KHz

2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0

Vdd(V)

vs. Temperature

= 8MHz

CPU

25°

-45° 90° 130°

3.0

2.0

2.4 2.8 3.2 3.6 4 4.4 4.8 5.2 5.6

Vdd (V)

13.4.2 On-chip peripherals

Symbol Parameter Conditions Typ Unit

=4MHz VDD=3.0V 300

DD(AT)

DD(SPI)

DD(ADC)

12-bit Auto-Reload Timer supply current

SPI supply current

ADC supply current when converting

Notes:

1. Data based on a differential I

mode at f

cpu

=8MHz.

2. Data based on a differential I tion (data sent equal to 55h).

3. Data based on a differential I plifier off.

measurement between reset configuration (timer stopped) and a timer running in PWM

measurement between reset configuration and a permanent SPI master communica-

measurement between reset configuration and continuous A/D conversions with am-

CPU

=8MHz VDD=5.0V 1000

CPU

=4MHz VDD=3.0V 50

CPU

=8MHz VDD=5.0V 300

CPU

=3.0V 250

ADC

=4MHz

=5.0V 1100

µA

100/133

ST ST7LITE2 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

1 INTRODUCTION

2 PIN DESCRIPTION

3 REGISTER & MEMORY MAP

4 FLASH PROGRAM MEMORY

4.1 Introduction

4.2 Main Features

4.3 PROGRAMMING MODES

4.4 ICC interface

4.5 Memory Protection

4.6 Related Documentation

4.7 Register Description

5 DATA EEPROM

5.1 INTRODUCTION

5.2 MAIN FEATURES

5.3 MEMORY ACCESS

5.4 POWER SAVING MODES

5.5 ACCESS ERROR HANDLING

5.6 Data EEPROM Read-out Protection

5.7 REGISTER DESCRIPTION

6 CENTRAL PROCESSING UNIT

6.1 INTRODUCTION

6.2 MAIN FEATURES

6.3 CPU REGISTERS

7 SUPPLY, RESET AND CLOCK MANAGEMENT

7.1 INTERNAL RC OSCILLATOR ADJUSTMENT

7.2 PHASE LOCKED LOOP

7.3 REGISTER DESCRIPTION

7.4 MULTI-OSCILLATOR (MO)

7.5 RESET SEQUENCE MANAGER (RSM)

7.6 SYSTEM INTEGRITY MANAGEMENT (SI)

8 INTERRUPTS

8.1 NON MASKABLE SOFTWARE INTERRUPT

8.2 EXTERNAL INTERRUPTS

8.3 PERIPHERAL INTERRUPTS

9 POWER SAVING MODES

9.1 INTRODUCTION

9.2 SLOW MODE

9.3 WAIT MODE

9.4 HALT MODE

9.5 ACTIVE-HALT MODE

9.6 AUTO WAKE UP FROM HALT MODE

10 I/O PORTS

10.1 INTRODUCTION

10.2 FUNCTIONAL DESCRIPTION

10.4 UNUSED I/O PINS

10.3 I/O PORT IMPLEMENTATION

10.5 LOW POWER MODES

10.6 INTERRUPTS

10.7 DEVICE-SPECIFIC I/O PORT CONFIGURATION

11 ON-CHIP PERIPHERALS

11.1 WATCHDOG TIMER (WDG)

11.2 12-BIT AUTORELOAD TIMER 2 (AT2)

11.3 LITE TIMER 2 (LT2)

11.4 SERIAL PERIPHERAL INTERFACE (SPI)

11.5 10-BIT A/D CONVERTER (ADC)

12 INSTRUCTION SET

12.1 ST7 ADDRESSING MODES

12.2 INSTRUCTION GROUPS

13 ELECTRICAL CHARACTERISTICS

13.1 PARAMETER CONDITIONS

13.2 ABSOLUTE MAXIMUM RATINGS

13.3 OPERATING CONDITIONS

13.4 SUPPLY CURRENT CHARACTERISTICS