ST ST7263 User Manual

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查询ST72631供应商

ST7263

LOW SPEED USB 8-BIT MCU F AMILY with up to 16K MEMORY,

up to 512 BYTES RAM, 8-BIT ADC, WDG, TIMER, SCI

■ Up to 16Kbytes program memory

■ Data RAM: up to 512 bytes with 64 bytes stack

■ Run, Wait and Halt CPU modes

■ 12 or 24 MH z os c illator

■ RAM retention mode

■ USB (Universal Serial Bus) Interface with DMA

for low speed applications compliant with USB

1.5 Mbs specification (version 1.1) and USB HID specifications (version 1.0)

■ Integrated 3.3V voltage regulator and

transceivers

■ Suspend and Resume operations

■ 3 endpoints with programmable in/out

configuration

■ 19 programmable I/O lines with:

– 8 high current I/Os (10mA at 1.3V) – 2 very high current pure Open Drain I/Os

(25mA at 1.5V)

– 8 lines individually programmable as interrupt

inputs

■ Optional Low Voltage Detector (LVD)

■ Programmable Watchdog for system reliability

■ 16-bit Timer with:

– 2 Input Captures – 2 Output Compares – PWM Generation capabilities – External Clock input

■ Asynchronous Serial Communications Interface

(8K and 16K program memory versions only)

■ I

C Multi Master Interface up to 400 KHz

(16K program memory version only)

■ 8-bit A/D Converter (ADC) with 8 channels

■ Fully static operation

■ 63 basic instructions

■ 17 main addressing modes

■ 8x8 unsigned multiply instruction

■ True bit manipulation

■ Versatile Development Tools (und er Windows)

including assembler, linker, C-compiler, archiver, source level debugger, software library, hardware emulator, programming boards and gang programmers

PSDIP32

CSDIP32W

SO34 (Shrink)

& I2C

DATASHEET

Table 1. Device Summary

Features

ROM - OTP (bytes) 16K 8K 4K RAM (stack) - bytes 512 (64) 256 (64)

Peripherals Operating Supply 4.0V to 5.5V

CPU frequency 8 Mhz (with 24 MHz oscillator) or 4 MHz (with 12 MHz oscillator) Operating temperature 0°C to +70°C

Packages SO34/SDIP32 EPROM device ST72E631

Watchdog, 16-bit timer, SCI, I

Note 1: EPROM version for development only

August 2000 1/109

ST72631

USB

C, ADC,

ST72632 ST72633

Watchdog, 16-bit timer,

SCI, ADC, USB

(CSDIP32W)

Watchdog, 16-bit timer,

ADC, USB

Rev. 1.8

Table of Contents

1 GENERAL DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

1.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

1.2 PIN DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

1.3 EXTERNAL CONNECTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

1.4 REGISTER & MEMORY MAP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

1.5 EPROM/OTP PROGRAM MEMORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

1.5.1 EPROM ERASURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

2 CENTRAL PROCESSING UNIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

2.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

2.2 MAIN FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

2.3 CPU REGISTERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

3 CLOCKS AND RESET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

3.1 CLOCK SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

3.1.1 General Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

3.1.2 External Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

3.2 RESET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

3.2.1 Low Voltage Detector (LVD) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

3.2.2 Watchdog Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

3.2.3 External Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

4 INTERRUPTS AND POWER SAVING MODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

4.1 INTERRUPTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

4.1.1 Interrupt Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

4.2 POWER SAVING MODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

4.2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

4.2.2 HALT mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

4.2.3 WAIT mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

5 ON-CHIP PERIPHERALS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

5.1 I/O PORTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

5.1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

5.1.2 Functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

5.1.3 I/O Port Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

5.1.4 Port A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

5.1.5 Port B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

5.1.6 Port C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

5.1.7 Register Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

5.2 MISCELLANEOUS REGISTER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

5.3 WATCHDOG TIMER (WDG) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

5.3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

5.3.2 Main Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

5.3.3 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

5.3.4 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

5.3.5 Register Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

5.4 16-BIT TIMER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

5.4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

5.4.2 Main Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

109

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5.4.3 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

5.4.4 Low Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

5.4.5 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

5.4.6 Summary of Timer modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

5.4.7 Register Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

5.5 SERIAL COMMUNICATIONS INTERFACE (SCI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

5.5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

5.5.2 Main Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

5.5.3 General Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

5.5.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

5.5.5 Low Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

5.5.6 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

5.5.7 Register Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

5.6 USB INTERFACE (USB) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

5.6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

5.6.2 Main Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

5.6.3 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

5.6.4 Register Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

5.6.5 Programming Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

5.7 I²C BUS INTERFACE (I²C) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

5.7.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

5.7.2 Main Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

5.7.3 General Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

5.7.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

5.7.5 Low Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

5.7.6 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

5.7.7 Register Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

5.8 8-BIT A/D CONVERTER (ADC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

5.8.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

5.8.2 Main Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

5.8.3 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

5.8.4 Low Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

5.8.5 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

5.8.6 Register Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

6 INSTRUCTION SET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

6.1 ST7 ADDRESSING MODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

6.1.1 Inherent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

6.1.2 Immediate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

6.1.3 Direct . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

6.1.4 Indexed (No Offset, Short, Long) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

6.1.5 Indirect (Short, Long) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

6.1.6 Indirect Indexed (Short, Long) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

6.1.7 Relative Mode (Direct, Indirect) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

6.2 INSTRUCTION GROUPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

7 ELECTRICAL CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

7.1 ABSOLUTE MAXIMUM RATINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

7.2 THERMAL CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

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ST7263

7.3 OPERATING CONDITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

7.4 POWER CONSUMPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

7.5 I/O PORT CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

7.6 LOW VOLTAGE DETECTOR (LVD) CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . 98

7.7 CONTROL TIMING CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

7.8 COMMUNICATION INTERFACE CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . 99

7.8.1 USB - Universal Bus Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

7.8.2 I2C - Inter IC Control Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

7.9 8-BIT ADC CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

8 PACKAGE CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

8.1 PACKAGE MECHANICAL DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

9 DEVICE CONFIGURATION AND ORDERING INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . 106

9.1 DEVICE ORDERING INFORMATION AND TRANSFER OF CUSTOMER CODE . . . . . 106

9.2 ST7 APPLICATION NOTES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

9.3 TO GET MORE INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

10 SUMMARY OF CHANGES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

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1 GENERAL DESCRIPTION

1.1 INTRODUCTION

ST7263

The ST7263 Microcontrollers form a sub family of the ST7 dedicated to USB applications. The devices are based on an industry-standard 8-bit core and feature an enhanced instruction set. They operate at a 24MHz or 12 MHz oscillator frequency. Under software control, the ST7263 MCUs may be placed in either Wait or Halt modes, thus reducing power consumption. The enhanced instruction set and addressing modes afford real programming potential. In addition to standard 8-bit data management, the ST7263 MCUs feature true bit manipulation, 8x8 unsigned multiplication and indirect addressing modes. The devices include an ST7 Core, up to 16K program memory, up to 512 bytes RAM, 19 I/O lines and the following on-chip peripherals:

– USB low speed interface with 3 endpoints with

programmable in/out configuration using the DMA architecture with embedded 3.3V voltage regulator and transceivers (no external components are needed).

– 8-bit Analog-to-Digital converter (ADC) with 8

multiplexed analog inputs

Figure 1. General Block Diagram

Internal CLOCK

OSCIN

OSCOUT

V V

RESET

OSCILLATOR

POWER

SUPPLY

WATCHDOG

CONTROL

8-BIT CO RE

ALU

LVD

USB DMA

OSC/3

OSC/4 or OSC/2

(for USB)

– industry standard asynchronous SCI serial inter-

face (not on all products - see device summary

below) – digital Watchdog – 16-bit Timer featuring an External clock input, 2

Input Captures, 2 Output Compares with Pulse

Generator capabilit ies – fast I2C Multi Master interface (not on all prod-

ucts - see device summary) – Low voltage (LVD) reset ensuring proper power-

on or power-off of the device All ST7263 MCUs are available in ROM and OTP

versions. The ST72E631 is the EPROM version of the

ST7263 in CSDIP32 windowed packages. A specific mode is available to allow programming

of the EPROM user memory array. This is set by a specific voltage source applied to the V

pin.

I2C*

PORT A

16-BI TTIMER

ADDRESS AND DATA BUS

PORT B

ADC

PORT C

SCI*

(UART)

PA[7:0]

(8 bits)

PB[7:0]

(8 bits)

PC[2:0]

(3 bits)

/TEST

VPP/TEST

DDA

SSA

* not on all products ( ref er to Table 1: Device Summary)

PROGRAM

MEMORY

(4K/8K/16K Byte s)

RAM

(256/512 Bytes)

USB SIE

USBDP USBDM USBVCC

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ST7263

1.2 PIN DESCRI PTION Figure 2. 34-Pin SO Package Pinout

OSCOUT

OSCIN

PC2/USBOE

PC1/TDO

PC0/RDI

RESET

AIN7/IT8/PB7 AIN6/IT7/PB6

AIN5/IT6/PB5 AIN4/IT5/PB4

* V

on EPROM/OTP versions only

AIN3/PB3 AIN2/PB2 AIN1/PB1

(10mA) (10mA)

VPP/TEST

(10mA) (10mA) (10mA) (10mA) (10mA)

1 2 3 4 5 6 7 8 9 10 11 12 13

14 15 16

DDA

USBVCC

USBDM

USBDP

SSA

PA0/MCO

PA1

PA2

24 23

PA3/EXTCLK

PA4/ICAP1/IT1 PA5/ICAP2/IT2

PA6/OCMP1/IT3

PA7/OCMP2/IT4

PB0

(25mA)

(10mA)

/SDA

/SCL

/AIN0

Figure 3. 32-Pin SDIP Package Pinout

OSCOUT

OSCIN

PC2/USBOE

PC1/TDO

PC0/RDI

RESET

AIN7/IT8/PB7

AIN6/IT7/PB6

AIN5/IT6/PB5 AIN4/IT5/PB4

* V

on EPROM/OTP versions only

AIN3/PB3 AIN2/PB2

AIN1/PB1/

(10mA)

VPP/TEST*

(10mA) (10mA) (10mA) (10mA) (10mA)

10 11 12 13 14 15 16

1 2 3 4 5 6 7 8 9

USBVCC

USBDM

USBDP

PA0/MCO

PA1

26 25 24

PA2

PA3/EXTCLK

22 21

PA4/ICAP1/IT1 PA5/ICAP2/IT2

PA6/COMP1/IT3

PA7/COMP2/IT4

PB0

DDA

NC NC

SSA

(25mA)

(10mA)

/SDA

/SCL

/AIN0

6/109

PIN DESCRIPTION (Cont’d) RESET

(see Note 1): Bidirectional. This active low

signal forces the initialization of the MCU. This event is the top priority non maskable interrupt. This pin is switched low when the Watchdog has triggered or V

is low. It can be used to reset ex-

ternal peripherals. OSCIN/OSCOUT: Input/Output Oscillator pin.

These pins connect a pa rallel-resonant crystal, or an external sou rc e to the on -c h ip o s cilla t o r.

/TEST: EPROM programming input. This pin

must be held low during normal operating modes.

DD/VSS

(see Note 2): Main power supply and

Ground voltages.

DDA/VSSA

(see Note 2): Power Supply and

Ground for analog peripherals.

Table 2. Device Pin Description

ST7263

Alter na te Fu nct i ons : Several pins of the I/O ports

assume software programmable alternate functions as shown in the pin description.

Note 1: Adding t wo 100nF de coupling capa citors

together

and

on Reset pin (respectively connected to

) will significantly improve produc t electromag-

netic susceptibility performances. Note 2: To enhance reliability of operation, it is

recommended to conn ect

DDA

and V

on the application board. The same recommenda-

tions apply to

and VSS.

SSA

Pin n°

Pin Name

SO34

SDIP32

11V 2 2 OSCOUT O Oscillator output 3 3 OSCIN I Oscillator input 44V 5 5 PC2/USBOE I/O C 6 6 PC1/TDO I/O C 7 7 PC0/RDI I/O C 8 8 RESET I/O X X Reset

-- 9 NC -- Not connected

9 10 PB7/AIN7/IT8 I/O C 10 11 PB6/AIN6/IT7 I/O C 11 12 V 12 13 PB5/AIN5/IT6 I/O C 13 14 PB4/AIN4/IT5 I/O C 14 15 PB3/AIN3 I/O C 15 16 PB2/AIN2 I/O C 16 17 PB1/AIN1 I/O C 17 18 PB0/AIN0 I/O C 18 19 PA7/OCMP2/IT4 I/O C 19 20 PA6/OCMP1/IT3 I/O C

/TEST S Supply for EPROM and test input

Level Port / Control

Input Output

Type

Input

Output

float

S Power supply voltage (4V - 5.5V)

S Digital ground

T T T

10mA X XX XPort B7 ADC analog input 7

10mA X XX XPort B6 ADC analog input 6

10mA X XX XPort B5 ADC analog input 5

10mA X XX XPort B4 ADC analog input 4

10mA X XXPort B3 ADC analog input 3

10mA X XXPort B2 ADC analog input 2

10mA X XXPort B1 ADC analog input 1

10mA X XXPort B0 ADC Analog Input 0

T T

int

wpu

X X Port C2 USB Output Enable X X Port C1 SCI transmit data output X X Port C0 SCI Receive Data Input

X XXPort A7 Timer Output Compare 2 X XXPort A6 Timer Output Compare 1

ana

Main

Function

(after reset)

Alternate Function

7/109

ST7263

Pin n°

Pin Name

SO34

SDIP32

20 21 PA5/ICAP2/IT2 I/O C 21 22 PA4/ICAP 1/IT1 I/O C 22 23 PA3/EXTC LK I/O C 23 24 PA2/SCL I/O C

-- 25 NC -- Not connected 24 26 NC -- Not connected 25 27 NC -- Not connected 26 28 PA1/SDA I/O C 27 29 PA0/MCO I/O C 28 30 V 29 31 USBDP I/O USB bidirectional data (data +) 30 32 USBDM I/O USB bidirectional data (data -) 31 33 USBVCC O USB power supply 32 34 V

SSA

DDA

Level Port / Control

Input Output

Type

Input

Output

float

T T T

25mA X T Port A2 I2C serial clock

25mA X T Port A1 I2C serial data

S Analog ground

S Analog supply voltage

int

wpu

X XXPort A5 Timer Input Captu re 2 X XXPort A4 Timer Input Captu re 1 X X Port A3 Timer External Clock

XXPort A0 Main Clock Output

ana

Main

Function

(after reset)

Alternate Function

*: if the peripheral is present on the device (see Table 1 Device Summary)

Legend / Abbreviations for Figure 2 and Tab le 2:

Type: I = input, O = output, S = supply In/Output lev e l: C

= CMOS 0.3VDD/0.7VDD with input trigger

Output level: 10mA = 10mA high sink (on N-buffer only)

25mA = 25mA very 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, T = True open drain Refer to “I/O PORTS” on page 25 for more details on the software configuration of the I/O ports. The RESET configuration of each pin is shown in bold. This configuration is kept as long as the device is

under reset state.

8/109

1.3 EXTERNAL CONNECTIONS

ST7263

The following figure shows the recom mended external connections for the device.

The V

pin is only used for programming OTP

and EPROM devices and must be tied to ground in user mode.

The 10 nF and 0. 1 µF decoupling capacitors on the power supply lines are a suggested EMC performance/cost tradeoff.

Figure 4. Recommended Extern al Connec tions

Optional if Low Voltage Detector (LVD) is used

EXTERNAL RESET CIRCUIT

10nF

0.1µF

The external reset network is intended to protect the device against parasitic resets, especially in noisy environments.

Unused I/Os shoul d be t ied hi gh to av oid any unnecessary power consumption on floating lines. An alternative solution is to program the unused ports as inputs with pull-up.

4.7K

RESET

0.1µF

See Clocks Section

Or configure unused I/O ports by software as input with pull-up

10K

OSCIN

OSCOUT

Unused I/O

9/109

ST7263

1.4 REGISTER & MEMORY MAP

As sho wn in Figure 5, the MCU is capable of ad- dressing 64K bytes of memories and I/O registers.

The available memory locations consist of 192 bytes of register location, up to 512 bytes of RAM and up to 16K bytes of user program memory. The RAM space includes up to 64 bytes for the stack from 0100h to 013Fh.

Figure 5. Me m ory Map

0000h

003Fh 0040h

023Fh

0240h

BFFFh C000h

E000h

F000h

FFEFh FFF0h

FFFFh

HW Registers

(see Table 4

256 Bytes RAM*

512 Bytes RAM*

Reserved

Program Memory*

16K Bytes

8K Bytes

4K Bytes

Interrupt & Reset Vectors (see Table 3 on page 10)

The highest address by tes contain the user re set and interrupt vectors.

IMPORTANT: Memory locations noted “Reserved” must neve r be ac cess ed. A cce ssing a reserved area can have unpredictable effects on the device

0040h

00FFh 0100h

013Fh

0040h

00FFh 0100h

013Fh 0140h

023Fh

Short Addressing RAM (192 Bytes)

Stack (64 Bytes)

Short Addressing RAM (192 Bytes)

Stack (64 Bytes)

16-bit Addressing RAM

(256 Bytes)

* Program memory and RAM sizes are product dependent (see Table 1 Device Summary)

Table 3. Interrupt Vector Map

Vector Address Description Masked by Remarks Exit from Halt Mode

FFF0-FFF1h FFF2-FFF3h FFF4-FFF5h FFF6-FFF7h

FFF8-FFF9h FFFA-FFFBh FFFC-FFFDh FFFE-FFFFh

USB End Suspend Mode Interrupt Vector

USB Interrupt Vector SCI Interrupt Vector*

C Interrupt Vector*

TIMER Interrupt Vector

IT1 to IT8 Interrupt Vector

TRAP (software) Interrupt Vector

RESET Vector

I- bit I- bit I- bit I- bit I- bit

I- bit none none

Internal Interrupt Internal Interrupt Internal Interrupt Internal Interrupt

External Interrupts

Internal Interrupt

CPU Interrupt

No No No

No Yes Yes

No Yes

* If the peripheral is present on the device (see Table 1 Device Summary)

10/109

ST7263

Table 4. Hardware Register Memory Map

Address Block Register Label Register name Reset Status Remarks

0000h 0001h

0002h 0003h

0004h 0005h

0006h 0007h

0008h ITIFRE Interrupt Register 00h R/W 0009h MISCR Miscellaneous Register F0h R/W 000Ah

000Bh 000Ch WDG CR Watchdog Control Register 7Fh R/W 000Dh

0010h 0011h

0012h 0013h 0014h 0015h 0016h 0017h 0018h 0019h 001Ah 001Bh 001Ch 001Dh 001Eh 001Fh

0020h 0021h 0022h 0023h 0024h

ADC

TIM

SCI

PADR PADDR

PBDR PBDDR

PCDR PCDDR

DR CSR

CR2 CR1 SR IC1HR IC1LR OC1HR OC1LR CHR CLR ACHR ACLR IC2HR IC2LR OC2HR OC2LR

SR DR BRR CR1 CR2

Port A Data Register Port A Data Direction Register

Port B Data Register Port B Data Direction Register

Port C Data Register Port C Data Direction Register

Reserved (2 Bytes)

ADC Data Register ADC control Status register

Reserved (4 Bytes)

Timer Control Register 2 Timer Control Register 1 Timer Status Register Timer Input Capture High Register 1 Timer Input Capture Low Register 1 Timer Output Compare High Register 1 Timer Output Compare Low Register 1 Timer Counter High Register Timer Counter Low Register Timer Alternate Counter High Register Timer Alternate Counter Low Register Timer Input Capture High Register 2 Timer Input Capture Low Register 2 Timer Output Compare High Register 2 Timer Output Compare Low Register 2

SCI Status Register SCI Data Register SCI Baud Rate Register SCI Control Register 1 SCI Control Register 2

00h 00h

1111 x000b 1111 x000b

00h 00h

00h 00h 00h xxh xxh 80h 00h FFh FCh FFh FCh xxh xxh 80h 00h

C0h xxh 00xx xxxxb xxh 00h

R/W R/W

Read only R/W

R/W R/W Read only Read only Read only R/W R/W Read only R/W Read only R/W Read only Read only R/W R/W

Read only R/W R/W R/W R/W

11/109

ST7263

Address Block Register Label Register name Reset Status Remarks

0025h 0026h 0027h 0028h 0029h 002Ah 002Bh 002Ch 002Dh 002Eh 002Fh 0030h 0031h

0032h 0038h

0039h 003Ah 003Bh 003Ch 003Dh 003Eh 003Fh

USB

2C1)

PIDR DMAR IDR ISTR IMR CTLR DADDR EP0RA EP0RB EP1RA EP1RB EP2RA EP2RB

OAR CCR SR2 SR1 CR

USB PID Register USB DMA address Register USB Interrupt/DMA Register USB Interrupt Status Register USB Interrupt Mask Register USB Control Register USB Device Address Register USB Endpoint 0 Register A USB Endpoint 0 Register B USB Endpoint 1 Register A USB Endpoint 1 Register B USB Endpoint 2 Register A USB Endpoint 2 Register B

Reserved (7 Bytes)

C Data Register

I Reserved I2C (7 Bits) Slave Address Register

C Clock Control Register

C 2nd Status Register

C 1st Status Register

C Control Register

xxh xxh xxh 00h 00h xxxx 0110b 00h 0000 xxxxb 80h 0000 xxxxb 0000 xxxxb 0000 xxxxb 0000 xxxxb

00h

00h 00h 00h 00h 00h

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

Note 1. If the peripheral is present on the device (see Table 1 Device Summary)

12/109

1.5 EPROM/OTP PROGRAM MEMORY

ST7263

The program memory of the ST72T63 may be programmed using the EPR OM program m ing b oards available from STMicroelectronics (see Table 26).

1.5.1 EPROM ERASURE

ST72Exxx EPROM devices are erased by exposure to high intensity UV light admitted through the transparent window. This exposure discharges the floating gate to its initial state through induced photo current.

It is recommended that the ST72Exxx devices be kept out of direct sunlight, since the UV content of sunlight can be sufficient to cause functional failure. Extended exposure t o room level fluorescent lighting may also cause erasure.

An opaque coating (paint, tape, label, etc...) should be placed over the package window if the product is to be operated under these lighting conditions. Covering the window also reduces I

in power-saving modes du e to photo-diode leakage currents.

An Ultraviolet source of wave length 2537 Å yielding a total integrated dosage of 15 Watt-sec/cm

is required to erase the ST72Exxx. The device will be erased in 15 to 30 minutes if such a UV lamp with a 12mW/cm

power rating is placed 1 inch from the device window without any interposed filters.

13/109

ST7263

2 CENTRAL PROCE SSI NG UNIT

2.1 INTRODUCTION

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

2.2 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 po wer modes

■ Maskable hardware interrupts

■ Non-maskable software interrupt

2.3 CPU REGISTERS

The 6 CPU registers shown in Figure 1 are not present in the memory mapping and are accessed by specific instructions.

Figure 6. CPU Registers

RESET VALUE = XXh

Accumulator (A)

The Accumulator is an 8-bit general purpose register used to hold operan ds 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 Cou nt er (P C )

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).

ACCUMULA T OR

X INDEX REGISTER

Y INDEX REGISTER

15 8

RESET VALUE = RESET VECTOR @ FFFEh-FFFFh

RESET VALUE = STACK HIGHER ADDRESS

14/109

PCH

RESET VALUE =

1C11HI NZ

1X11X1XX 70

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

The 8-bit Condition Code register c ontains the interrupt mask and four flags represent ative 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.

because the I bi t 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

This bit is set and cleared by hardware. It is representative of the result sign of the last arithmeti c, 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 instruc-

Bit 4 = H

Half carry

tions.

This bit is set by hardware when a carry occurs between bits 3 and 4 of t he 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 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.

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 interrup ts 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 whe n I is cleared.

Bit 0 = C

Carry/borrow.

This bit is set and cleared b y hardware and software. It indicates an overflow or an underflow has occurred during the last arithmetic operation. 0: No overflow or underflow has occurred. 1: An overflow or underflow has occurred.

This bit is driven by the SCF and RCF instructions and tested by the JRC and JRNC instructions. It is also affected by the “bit test and branch”, shift and rotate instructions.

By default an interrupt routine is not in terruptable

ST7263

15/109

ST7263

CPU REGISTERS (Cont’d) Stack Pointer (SP)

Read/Write Reset Value: 01 3Fh

15 8

00000001

0 0 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 7).

Since the stack is 64 bytes deep, the 10 most significant bits are forced by hardw are. Following a n MCU Reset, or after a Reset Stack Pointe r instruction (RSP), the Stack Pointer contains its reset value (SP5 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, wi thout indicating the s tack overflow. The previously stored information is then o verwritten and therefore lost. The stack also wraps in case of an underflow.

The stack is used to save the retu rn address during a subroutine call and the CPU context during an interrupt. The user may also directly manipulate the stack by means of the PUSH and POP instructions. In the case of an interrupt, the PCL is stored at the first location point ed to by the SP. Then the other registers are stored in the next locations as shown in Figure 7.

– 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 interrupt five locat ions i n the sta ck ar ea.

Figure 7. Stack Manipulation Example

@ 0100h

@ 013Fh

CALL

Subroutine

PCH PCL

Stack Higher Address = 013Fh Stack Lower Address =

Interrupt

Event

X PCH PCL PCH PCL

0100h

PUSH Y POP Y IRET

X PCH PCL PCH

PCL

X PCH PCL PCH PCL

PCH

PCL

RET

or RSP

16/109

3 CLOCKS AND RESET

3.1 CLOCK SYSTEM

ST7263

3.1.1 General Description

The MCU accepts either a Crystal or Ceramic resonator, or an external clock signal to drive the internal oscillator. The internal clock (f rived from the external oscillator frequency (f

CPU

) is de-

OSC

which is divided by 3 (and by 2 or 4 for USB, depending on the external clock used).

By setting the CLKDIV bit in the Miscellaneous Register, a 12 MHz external clock can be used giving an internal frequency of 4 MHz while maintaining a 6 MHz for USB (refer to Figure 10).

The internal clock signal (f

) is also routed to

CPU

the on-chip peripherals. The CPU clock signal consists of a square wave with a duty cycle of 50%.

The internal oscillat or is designed to operate with an AT-cut parallel resonant quartz or ceramic resonator in the frequency range specified for f

osc

The circuit shown in Figure 9 is recommended when using a crystal, and Table 5 Re commended

Values for 24 MHz Crystal Resonator lists the rec-

ommended capacitance. The crystal and associated components should be mounted as close as possible to the input pins in order to minimize output distortion and start-up stabilisation time.

Figure 8. External Clock Source Connections

OSCIN OSCOUT

EXTERNAL

CLOCK

Figure 9. Crystal/Ceramic Resonator

OSCOUT

OSCIN

Table 5. Recommended Values for 24 MHz Crystal Resonator

SMAX

OSCIN

OSCOUT

Note: R crystal (see crystal specification).

SMAX

Ω

56pF 47pF 22pF 56pF 47pF 22pF

1-10 M

Ω

1-10 M

Ω

1-10 M

Ω

is the equivalent serial resistor of the

3.1.2 External Clock

An external clock may be applied to the OSCIN input with the OSCOUT pin not connected, as shown on F igure 8. The t

specifications does

OXOV

not apply when using an external clock input. The equivalent specification of the external clock source should be used instead of t

OXOV

(see Sec-

tion 6.5 CONTROL TIMING).

Figure 10. Clock block diagram

CLKDIV

24 or

12 MHz

Crystal

8 or 4 MHz CPU and

peripherals)

6 MHz (USB)

17/109

ST7263

3.2 RESET

The Reset procedure is used to provide an orderly software start-up or to exit low power modes.

Three reset modes are provided: a low voltage (LVD) reset, a watchdog reset and an external reset at the RESET

pin.

A reset causes the reset vector to be fetched from addresses FFFEh and FFFFh in order to be loaded into the PC and with program execution starting from this point.

An internal circuitry provides a 4096 CPU clock cycle delay from the time that the oscillator becomes

During low voltage reset, the RESET thus permitting the MCU to reset other devices.

The Low Voltage Detector can be disabled by setting the LVD bit of the Miscellaneous Register.

3.2.2 Watchdog Reset

When a watchdog reset occurs, the RESET pulled low permitting the MCU to reset other devices in the same way as t he low voltage reset (Fig-

ure 11).

pin is held low,

pin is

active.

3.2.3 External Reset

3.2.1 Low Voltage Detector (LVD)

Low voltage reset circuitry generates a reset when V

is:

■ below V

when VDD is rising,

IT+

when VDD is falling.

IT-

The external reset is an active low input signal applied to the RESET pin of the MCU. As shown in Figure 14, the RESET

signal must stay low for a minimum of one and a half CPU clock cycles.

An internal Schmitt trigger at the RESET

pin is pro-

vided to improve noise immunity.

Table 6. List of secti ons affect ed by RESET, WA IT and HAL T (Ref er t o 3.5 for Wait a nd Hal t Modes )

Section RESET WAIT HALT

CPU clock running at 8 MHz X Timer Prescaler reset to zero X Timer Counter set to FFFCh X All Timer enable bit set to 0 (disable) X Data Direction Registers set to 0 (as Inputs) X Set Stack Pointer to 013Fh X Force Internal Address Bus to restart vector FFFEh,FFFFh X Set Interrupt Mask Bit (I-Bit, CCR) to 1 (Interrupt Disable) X Set Interrupt Mask Bit (I-Bit, CCR) to 0 (Interrupt Enable) X X Reset HALT latch X Reset WAIT latch X Disable Oscillator (for 4096 cycles) X X Set Timer Clock to 0 X X Watchdog counter reset X Watchdog register reset X Port data registers reset X Other on-chip peripherals: registers reset X

18/109

ST7263

Figure 11. Low Voltage Detector functional Diagram

RESET

LOW VOLTAGE

DETECTOR

FROM

WATCHDOG

RESET

INTERNAL

RESET

Figure 12. Low Voltage Reset Signal Output

IT+

RESET

Note: Hysteresis (V

Figure 13. Temporization timing diagram after an internal Reset

Addresses

IT+

temporization (4096 CPU clock cycles)

$FFFE

IT+-VIT-

) = V

hys

IT-

Figure 14. Reset Timing Diagram

DDR

OSCIN

OXOV

CPU

RESET

WATCHDOG RESET

Note: Refer to Electrical Characteristics for values of t

4096 CPU

CLOCK

CYCLES

, t

DDR

DELAY

OXOV

FFFE

, V

IT+

, V

FFFF

IT-

and V

hys

19/109

ST7263

4 INTERRUPTS AND POWER SAVING MODES

4.1 INTERRUPTS

The ST7 core may be interrupted by one of two different methods: maskable hardware interrupts as listed in Table 7 Interrupt Mapping and a non- maskable software interrupt (TRAP). The Interrupt processing flowchart is shown in Figure 15.

The maskable interrupts must be enabled clearing the I bit in order to be serviced. However, disabled interrupts may be latched and processed when they are enabled (see external interrupts subsec tion) .

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

Table 7 Interrupt Mapping for vector addresses).

The interrupt service routine should finish with the IRET instruction which c auses the conten ts o f the saved registers to be recovered from the stack.

Note: As a consequence of the IRET instruction, the I bit will be cleared a nd the main pro gram will resume.

Priority management

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

In the case several interrupts are simultaneously pending, a hardware priority defines which one will be serviced first (see Table 7 Interrupt Mapping).

Non maskable software interrupts

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 15.

Interrupts a n d Low power mod e

All interrupts allow the processor to leave the Wait low power mode. Only external and specific mentioned interrupts allow the processor to leave the Halt low power mode (refer to t he “Exit f rom HALT“ column in Table 7 Interrupt Mapping).

External interrupts

The pins ITi/PAk and ITj/P Bk (i=1,2; j= 5,6; k=4,5) can generate an i nterrupt when a rising edge occurs on this pin. Conversely, pins ITl/PAn and ITm/ PBn (l=3,4; m= 7,8; n=6,7) can generat e an interrupt when a falling edge occurs on this pin.

Interrupt generation will occur if it is enabl ed with the ITiE bit (i=1 to 8) in the ITRFRE register and if the I bit of the CCR is reset.

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

– an access to the status register while the flag is

set followed by a read or write of an associated register.

Notes:

1. 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.

2. All interrupts allow the processor to leave the Wait low power mode.

3. Exit from Halt mode may only be triggered by an External Interrupt on one of the ITi ports (PA4-PA7 and PB4-PB7), an end suspend mode Interrupt coming from USB peripheral, or a reset.

20/109

INTERRUPTS (Cont’d) Figure 15. I nt errupt Proces s ing Fl owchart

FROM RESET

ST7263

EXECUTE INSTRUCTION

Table 7. Int errupt Mapp in g

N°

Source

Block

BIT I SET

FETCH NEXT INSTRUCTION

RESTORE PC, X, A, CC FROM STACK

THIS CLEARS I BIT BY DEFAULT

IRET

Description

Label

INTERRUPT

STACK PC, X, A, CC

SET I BIT

LOAD PC FROM INTERRUPT VECTOR

Priority

Order

Exit from

HALT

Vector

Address

RESET Reset

TRAP Software Interrupt no FFFCh-FFFDh

N/A

USB End Suspend Mode ISTR 1 ITi External Interrupts ITRFRE FFF8h-FFF9h 2 TIMER Timer Peripheral Interrupts TIMSR

C Peripheral Interrupts

I2CSR1 I2CSR2

4 SCI SCI Peripheral Interr upts SCISR FFF2h-FFF3h 5 USB USB Peripheral Interrupts ISTR FFF0h-FFF1h

Highest

Priority

Lowest

Priority

yes FFFEh-FFFFh

yes

FFFAh-FFFBh

FFF6h-FFF7h FFF4h-FFF5h

21/109

ST7263

INTERRUPTS (Cont’d)

4.1.1 Interrupt Register INTERRUPTS REGISTER (ITRFRE)

Address: 0008h — Read/Write Reset Value: 0000 0000 (00h)

IT8E IT7E IT6E IT5E IT4E IT3E IT2E IT1E

Bit 7:0 = ITiE (i=1 to 8).

Bits

Interrupt Enable Control

If an ITiE bit is set, the corresponding interrupt is generated when

– a rising edge occurs on the pin PA4/IT1 or PA5/

IT2 or PB4/IT5 or PB5/IT6 or – a falling edge occurs on the pin PA6/IT3 or PA7/

IT4 or PB6/IT7 or PB7/IT8 No interrupt is generated elsewhere. Note: Analog input must be disabled for interrupts

coming from port B.

22/109

4.2 POWER SAVI NG MO DE S

ST7263

4.2.1 Introd uct i on

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

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 by 3 (f

CPU

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.

4.2.2 HALT mode

The HALT mode is the MCU lowest power consumption mode. The HALT mode is entered by executing the HALT instruction. The internal oscillator is then turned off, causing all internal processing to be stopped, including the operation of the on-chip peripherals.

When entering HALT mode, the I bit in the Condition Code Register is cleared. Thus, any of the external interrupts (ITi or US B end suspend mode), are allowed and if an interrupt occurs, the CPU clock becomes active.

The MCU can exit HALT m ode on reception of either an external interrupt on ITi, an end suspend mode interrupt coming from USB peripheral, or a reset. The oscillat or is t hen t urned on and a stabilization time is provided before rele asing CPU operation. The stabilization time is 4096 CPU clock cycles. After the start up delay, the CPU continues operation by servicing the interrupt which wakes it up or by fetching the reset vector if a reset wakes it up.

Figure 16. HAL T Mode Flow C hart

HALT INSTRUCTION

OSCILLATOR PERIPH. CLOCK CPU CLOCK

I-BIT

RESET

EXTERNAL

INTERRUPT*

OSCILLATOR PERIPH. CLOCK CPU CLOCK I-BIT

4096 CPU CLOCK

CYCLES DELAY

FETCH RESET VECTOR

OR SERVICE INTERRUPT

OFF

OFF CLEARED

ON SET

Note: Before servicing an interrupt, the CC register is pushed on the stac k. T he I -Bit i s se t du ring the interrupt routine and cleared when the CC register is popped.

23/109

ST7263

POWER SAVING MODES (Cont’d)

4.2.3 WAIT mode

Figure 17. WAIT Mode Flow Chart

WAIT mode places the MCU in a low power consumption mode by stopping the CPU. This pow er s av in g mode is s elected b y ca llin g the “WFI” ST7 software instruction. All peripherals remain active. During WAIT mode, the I bit of the CC register is forced to 0, to enable all interrupts. All other registers and mem ory remain unchanged. The MCU remains in WAIT mode until an interrupt or Reset occu rs, where upon the Program Counter branc hes to the starting address of the interrupt or Reset service routine. The MCU will r e main in W AIT mod e unt il a Rese t or an Interrupt occurs, causing it to wake up.

Refer to Figure 17.

INTERRUPT

WFI INSTRUCTION

OSCILLATOR PERIPH. CLOCK CPU CLOCK

I-BIT

RESET

OSCILLATOR PERIPH. CLOCK

CPU CLOCK

I-BIT

OFF CLEARED

ON SET

24/109

IF RESET

4096 CPU CLOCK

CYCLES DELAY

FETCH RESET VECTOR

OR SERVICE INTERRUPT

Note: Before servicing an interrupt, the CC register is pushed on the sta ck. The I-Bit is s et d uring the inte rrupt routine and cleared when the CC register is popped.

5 ON-CHIP PERIPHERALS

5.1 I/O PORTS

ST7263

5.1.1 Introd uct i on

The I/O ports offer different functional modes:

– transfer of data through digital inputs and outputs and for specific pins: – analog signal input (ADC) – alternate signal input/output for the on-chip pe-

ripherals. – external interrupt generation An I/O port i s com pos ed of up to 8 pins. E ach pin

can be programmed independently as digital input (with or without interrupt generation) or digital output.

5.1.2 Functi onal descri ption

Each port is associated to 2 main registers: – Data Register (DR) – Data Direction Register (DDR) Each I/O pin may be programmed using the corre-

sponding register bits in DDR register: bit X corresponding to pin X of the port. The same correspondence is used for the DR register.

Table 8. I/O Pin Functi ons

DDR MODE

0 Input 1 Output

Inpu t Mode s

The input configuration is sele cted by clearing the corresponding DDR register bit.

In this case, reading the DR register returns the digital value applied to the external I/O pin.

Note 1: All the inputs are triggered by a Schmitt trigg er. Note 2: When switching from input mode to output mode, the DR register should be written first to output the correct value as soon as the port is configured as an output.

Interrupt function

When an I/O is configured in Input with Interrupt, an event on this I/O can generate an external In-

terrupt request to the CPU. The interrupt sensitivity is given independently according to the description mentioned in the ITRFRE interrupt register.

Each pin can independently generate an Interrupt request.

Each external interrupt vector is linked t o a dedicated group of I/O port pins (see Interrupts section). If more than one input pin is selected simultaneously as interrupt source, this is logically ORed. For this reason if one of the interrupt pins is tied low, it masks the other ones.

Output Mode

The pin is configured in output mode by setting the corresponding DDR register bit (see Table 7).

In this mode, writing “0” or “1” to the DR register applies this digital value to the I/O pin through the latch. Then reading the DR register returns the previously stored value.

Note: In this mode, the interrupt function is disabled.

Digital Alternate Func ti on

When an on-chip peripheral is configured to use a pin, the alternate function is au tomatically selected. This alternate function takes priority over standard I/O programming. When the signal is coming from an on-chip peripheral, the I/O pin is automatically configured in output mode (push-pull or open drain according to the peripheral).

When the signal is goi ng to an on-chip peripheral, the I/O pin ha s to be configured in i nput mode. In this case, the pin’s state is a lso digitally readable by addressing the DR register.

Notes:

1. Input pull-up configuration can cause an unex pected value at the input of the alternate peripheral input.

2. When the on-chip peripheral uses a pin as input and output, this pin must be configured as an input (DDR = 0).

Warning

: The alternate func tion m us t not be a cti-

vated as long as the pin is configured as input with interrupt, in order to avoid generating spurious interrupts.

25/109

ST7263

I/O PORTS (Cont’d) Analog Alternate Function

When the pin is used as an ADC input the I/O must be configured as input, floating. The analog multiplexer (controlled by the ADC registers) switches the analog voltage present o n the selected pin to the common ana log rail which i s c onnect ed to the ADC input.

It is recommended not to change the voltage level or loading on any port pin while conversion is in progress. Furthermore it i s recommended not to

have clocking pins locat ed close t o a selected analog pin.

Warning

within the limits stat ed in the A bsolute Max imum Ratings.

5.1.3 I/O Port Implementation

The hardware implementation on each I/O port depends on the settings in the DDR register and specific feature of the I/O port such as ADC Input or true open drain.

: The analog input voltage level must be

26/109

I/O PORTS (Cont’d)

5.1.4 Port A Table 9. Port A0, A3, A4, A5, A6, A7 Description

ST7263

PORT A

Input* Output Signal Condition

I / O Alternate Function

PA0 with pull-up push-pull MCO (Main Clock Output) MCO = 1 (MISCR)

PA3 with pull-up push-pull Timer EXTCLK

PA4 with pull-up

PA5 with pull-up

PA6 with pull-up

PA7 with pull-up

push-pull

Timer ICAP1 IT1 Schmitt triggered input IT1E = 1 (ITIFRE) Timer ICAP2 IT2 Schmitt triggered input IT2E = 1 (ITIFRE) Timer OCMP1 OC1E = 1 IT3 Schmitt triggered input IT3E = 1 (ITIFRE) Timer OCMP2 OC2E = 1 IT4 Schmitt triggered input IT4E = 1 (ITIFRE)

CC1 =1 CC0 = 1 (Timer CR2)

*Reset State

Figure 18. PA0, PA3, PA4, PA5, PA6, PA7 Configuration

ALTERNATE ENABLE ALTERNATE OUTPUT

P-BUFFER

DATA BUS

DR SEL

ALTERNATE INPUT

LATCH

DDR

LATCH

DDR SEL

PULL-UP

ALTERNATE ENABLE

N-BUFFER

ALTERNATE ENABLE

CMOS SCHMITT TRIGGER

PAD

DIODES

27/109

ST7263

I/O PORTS (Cont’d)

Table 10. PA1, PA2 Description

PORT A

Input* Output Signal Condition

I / O Alternate Function

PA1 without pull-up Very High Current open drain SDA (I2C data) I2C enable PA2 without pull-up Very High Current open drain SCL (I2C clock) I2C enable *Reset State

Figure 19. PA1, PA2 Configuration

ALTERNATE ENABLE

ALTERNATE OUTPUT

LATCH

DDR

LATCH

DATA BUS

DDR SEL

PAD

DR SEL

N-BUFFER

ALTERNATE ENABLE

CMOS SCHMITT TRIGGER

28/109

ST7263

I/O PORTS (Cont’d)

5.1.5 Port B Table 11. Port B Description

PORT B I/O Alternate Function

Input* Output Signal Condition

PB0 without pull-up push-pull Analog input (ADC) CH[2:0] = 000 (ADCCSR) PB1 without pull-up push-pull Analog input (ADC) CH[2:0] = 001 (ADCCSR) PB2 without pull-up push-pull Analog input (ADC) CH[2:0]= 010 (ADCCSR) PB3 without pull-up push-pull Analog input (ADC) CH[2:0]= 011 (ADCCSR)

PB4 without pull-up push-pull

PB5 without pull-up push-pull

PB6 without pull-up push-pull

PB7 without pull-up push-pull

*Reset State

Figure 20. Port B C onfi guration

ALTERNAT E EN ABL E

ALTERNATE OUTPUT

LATCH

DDR

COMMON ANALOG RAIL

DATA BUS

LATCH

ANALOG ENABLE (ADC)

Analog input (ADC) CH[2:0]= 100 (ADCCS R) IT5 Schmitt triggered input IT4E = 1 (ITIFRE) Analog input (ADC) CH[2:0]= 101 (ADCCS R) IT6 Schmitt triggered input IT5E = 1 (ITIFRE) Analog input (ADC) CH[2:0]= 110 (ADCCS R) IT7 Schmitt triggered input IT6E = 1 (ITIFRE) Analog input (ADC) CH[2:0]= 111 (ADCCS R) IT8 Schmitt triggered input IT7E = 1 (ITIFRE)

P-BUFF ER

ALTERNATE EN ABLE

PAD

ALTER N A T E INP U T

DDR SEL

DR SEL

ANALOG SWITCH

N-BUFFER

DIGITA L EN ABL E

ALTERNATE EN ABLE

DIODES

29/109

ST7263

I/O PORTS (Cont’d)

5.1.6 Port C Table 12. Port C Description

PORT C

I / O Alternate Function

Input* Output Signal Condition

PC0 with pull-up push-pull RDI (SCI input) PC1 with pull-up push-pull TDO (SCI output) SCI enable

PC2 with pull-up push-pull

USBOE (USB output enable)

USBOE =1 (MISCR)

*Reset State

Figure 21. P ort C Conf i gu ra ti on

ALTER N AT E ENABLE ALTERNATE OUTPUT

DR LATCH

DATA BUS

DDR LATCH

PULL-UP

ALTERNAT E EN ABL E

P-BUFFER

PAD

ALTERNATE INPUT

30/109

DDR SEL

DR SEL

N-BUFFER

ALTERNATE ENABLE

CMOS SCHMITT TRIGGER

DIODES

I/O PORTS (Cont’d)

5.1.7 Register Description DATA REGISTERS (PxDR)

Port A Data Register (PADR): 0000h Port B Data Register (PBDR): 0002h Port C Data Register (PCDR): 0004h Read/Write Reset Value Port A: 0000 0000 (00h) Reset Value Port B: 0000 0000 (00h) Reset Value Port C: 1111 x000 (FXh)

Note: f or Port C, unused bits (7-3) are not acces-

DATA DIRECTION REGISTER (PxDDR)

Port A Data Direction Register (PADDR): 0001h Port B Data Direction Register (PBDDR): 0003h Port C Data Direction Register (PCDDR): 0005h Read/Write Reset Value Port A: 0000 0000 (00h) Reset Value Port B: 0000 0000 (00h) Reset Value Port C: 1111 x000 (FXh) Note: for Port C, unused bits (7-3) are not acces-

sible

sible.

D7 D6 D5 D4 D 3 D2 D1 D0

DD7 DD6 DD 5 DD4 DD3 DD2 DD1 DD0

ST7263

Bit 7:0 = DD7-DD0

Data Direction Register 8 bits.

The DDR register gives the input /output direction

Bit 7:0 = D7-D0

Data Register 8 bits.

The DR register has a specific behaviour according to the selected input/output configuration. Writing the DR register is always taken in account

configuration of the pins. Each bits is set and cleared by software.

0: Input mode 1: Output mode

even if the pin is configured as an input. Reading the DR register returns ei ther the DR register latch content (pin configured as output) or the digital value applied to the I/O pin (pin configured as input).

Table 13. I/O Ports Register Map

Address

(Hex.)

00 PADR MSB LSB 01 PADDR MSB LSB 02 PBDR MSB LSB 03 PBDDR MSB LSB 04 PCDR MSB LSB 05 PCDDR MSB LSB

Label

76543210

31/109

ST7263

5.2 MISCELLANEOUS REGISTER

Bit 2 = CLKDIV

Address: 0009h — Read/Write Reset Value: 1111 0000 (F0h)

----LVDCLKDIVUSBOEMCO

Bit 7:4 = Reserved

This bit is set by software and only cleared by hardware after a reset. If this bit is set, it enables the use of a 12 MHz external os cillator (refer to Figure 10

on page 17).

0: 24 MHz external oscillator 1: 12 MHz external oscillator.

Bit 1 = USBOE

Clock Divider

USB enable.

If this bit is set, the port PC2 outputs the USB out-

Bit 3 = LVD

Low Voltage Detector.

This bit is set by software and only cleared by hardware after a reset.

put enable signal (at “1” when the ST7 USB is transmitting data).

Unused bits 7-4 are set.

0: LVD enabled 1: LVD disabled

Bit 0 = MCO

Main Clock Out selection

This bit enables the MCO alternate function on the PA0 I/O port. It is set and cleared by software. 0: MCO alternate function disabled (I/O pin free for

general-purpose I/O)

1: MCO alternate function enabled (f

port)

on I/O

CPU

32/109

5.3 WATCHDOG TIMER (WDG)

ST7263

5.3.1 Introd uction

The Watchdog tim er is used to detect t he occurrence of a software fault, usually generated by external interference or by unforeseen logi cal conditions, which causes the application program to abandon its normal seque nce. The W atchdog circuit generates an MCU reset o n expiry of a programmed time period, unless the program refresh-

es the counter’s contents before the T6 bit becomes cleared.

Figure 22. Watc hdog Block Diagram

RESET

WATCHDOG CONTROL REGISTER (CR)

WDGA

T6 T0

7-BIT DOWNCOUNTER

5.3.2 Main Features

■ Programmable timer (64 increments of 49152

CPU cycles)

■ Programmable reset

■ Reset (if watchdog activated) when the T6 bit

reaches zero

CPU

CLOCK DIVIDER

49152

33/109

ST7263

WATCHD OG TI M E R (Cont’d)

5.3.3 Functional Description

The counter value stored in the CR register (bits T6:T0), is decremented every 49,152 machine cycles, and the length of the timeout period can b e programmed by the user in 64 increments.

If the watchdog is activated (the W DGA bit is s et) and when the 7-bit timer (bits T6:T0) rolls over from 40h to 3Fh (T6 becom es cleared), it initiates a reset cycle pu lling lo w t he rese t pi n fo r typical ly 500ns.

The application program must write in the CR register at regular intervals during normal operation to prevent an MCU reset. The value to b e stored in the CR register must be between FFh and C0h (see Table 14 . Watchdog Timing (fCPU = 8

MHz)):

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

diate reset

– The T5:T0 bits contain the number of increments

which represents the time delay before the watchdog produces a reset.

Table 14. Watchdog Timing (f

CR Register

initial value

Max FFh 393.216

Min C0h 6.144

= 8 MHz)

CPU

WDG timeout period

(ms)

reset immediately after waking up the microcontroller.

– 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 ROM with the value 0x8E.

– As the HALT instruction clears the I bit in the CC

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

5.3.4 Interrupts

None.

Notes: Following a reset, the watchdog is disabled. Once activated it cannot be disabled, except by a reset.

The T6 bit can be used to generat e a sof t ware reset (the WDGA bit is set and the T6 bit is cleared).

5.3.3.1 Using Halt Mode with the WDG

The HALT instruction stops the oscillator. When the oscillator is stopped, the WDG stop s counting and is no longer able to generate a reset u ntil the microcontroller receives an external interrupt or a reset.

If an external interrupt is received, the WDG restarts counting after 4096 CPU clocks. If a reset is generated, the WDG is disabled (reset state).

Recommendations

– Mak e sure that an external event is available to

wake up the microcontroller from Halt mode.

– Before ex ecuting the HALT instruction, refresh

the WDG counter, to avoid an unexpected WDG

34/109

5.3.5 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

Bit 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).

WATCHD OG TI M E R (Cont’d) Table 15. Watchdog Time r Register Map and Rese t Values

Address

(Hex.)

Label

WDGCR

Reset Value

76543210

WDGA

ST7263

35/109

ST7263

5.4 16-BIT TIMER

5.4.1 Introd uction

The timer consists of a 16-bit free-running counter driven by a programmable prescaler.

It may be used for a variety of purposes, including measuring the pulse lengths of up to two input signals (

input capture

waveforms (

) or generating up to two output

output compare

and

PWM

Pulse lengths and waveform perio ds c an be m odulated from a few microseconds to several milliseconds using the timer prescaler and the CPU clock prescaler.

Some ST7 devices have two on-chip 16-bit timers. They are completely independent, and do not share any resources. They are synchronized a fter a MCU reset as long as the timer clock frequencies are not modified.

This description covers one or two 16-bit timers. In ST7 devices with two timers, regi ster names are prefixed with TA (Timer A) or TB (Timer B).

5.4.2 Main Features

■ Programmable prescaler: f

■ Overflow status flag and maskable interrupt

■ External clock inpu t (must be at le ast 4 times

slower than the CPU

clock speed) with the choice

divided by 2, 4 or 8.

CPU

of active edge

■ Output compare functions with:

– 2 dedicated 16-bit registers – 2 dedicated programmable signals – 2 dedicated status flags – 1 dedicated maskable interrupt

■ Input capture functions with:

– 2 dedicated 16-bit registers – 2 dedicated active edge selection signals – 2 dedicated status flags – 1 dedicated maskable interrupt

■ Pulse Width Modulation mode (PWM)

■ One Pulse mode

■ 5 alternate functions on I/O ports (ICAP1, ICAP2,

OCMP1, OCMP2, EXTCLK)*

5.4.3 Functional Description

5.4.3.1 Counter

The main block of the Programmab le Timer is a 16-bit free running upcounter and its associated 16-bit registers. The 16-bit registers are made up of two 8-bit registers called high & low.

Counter Register (CR):

– Counter High Register (CHR) is the most sig-

nific a nt byte (MS B y te ) .

– Counter Low Register (CLR) is the least sig-

nificant byte (LS Byte).

Alternate Counter Register (ACR)

– Alternate Count er Hi gh Regi ster ( ACHR) is th e

most significant byte (MS Byte).

– Alternate Counter Low Register (ACLR) is the

least significant byt e (LS Byte).

These two read-only 16-bit registers contain the same value but with the difference that reading the ACLR register does not clear the TOF bit (Timer overflow flag), located in the Stat us register (SR). (See note at the end of paragraph titled 16-bit read sequence).

Writing in the CLR register or ACLR register resets the free running counter to the FFFCh value. Both counters have a reset value of FFFCh (this is the only value which is reloaded in the 16-bit timer). The reset value of both counters is also FFFCh in One Pulse mode and PWM mode.

The timer clock depends on the cloc k control bits of the CR2 register, as illustrated in T able 1. The value in the counter register repeats every

131.072, 262.144 or 524.288 CPU clock cycles depending on the CC[1:0] bits. The timer frequency c an be f

CPU

/2, f

CPU

/4, f

CPU

or an external frequency.

The Block Diagram is shown in Figure 1. *Note: Some timer pins m ay not be av ai lable (not

bonded) in some ST7 devices. Refer to the device pin out description. When reading an input signal on a non-bonded pin, the value will always be ‘1’.

36/109

16-BIT TIMER (Cont’d) Figure 23. Timer Block Diagram

CPU

ST7263

ST7 INTERNAL BUS

MCU-PERIPHERAL INTERFACE

EXTCLK

EXEDG

1/2 1/4

1/8

CC[1:0]

8 high

COUNTER

ALTERNATE

COUNTER

OVERFLOW

DETECT

CIRCUIT

8 low

8-bit

buffer

high

OUTPUT

COMPARE

TIMER INTERNAL BUS

OUTPUT COMPARE

CIRCUIT

low

16 16

low

high

OUTPUT COMPARE REGISTER

88 8

high

INPUT

CAPTURE

EDGE DETECT

CIRCUIT1

EDGE DETECT

CIRCUIT2

8 8 8

low

high

low

INPUT

CAPTURE

ICAP1

ICAP2

(See note)

TIMER INTERRUPT

ICF2ICF1 000OCF2OCF1 TOF

(Status Register) SR

(Control Register 1) CR1

LATCH1

LATCH2

OC2E

PWMOC1E

OPMFOLV2ICIE OLVL1IEDG1OLVL2FOLV1OCIETOIE

EXEDG

IEDG2CC0CC1

(Control Register 2) CR2

Note: If IC, OC and TO interrupt requests have separate vectors then the last O R is not presen t (See device In t errupt Vector Table)

OCMP1

OCMP2

37/109

ST7263

16-BIT TIMER (Cont’d) 16-bit Read Sequence: (from either the Counter

Beginning of the sequence

Read

At t0

MS Byte

Other

instructions

Read

At t0 +∆t

LS Byte

Sequence completed

The user must read the MS Byte f irst, then the LS Byte value is buffered automatically.

This buffered value rem ains unchanged until the 16-bit read sequence is completed, even if the user reads the MS Byte several times.

After a complete reading sequence, if only the CLR register or ACLR register are read, they return the LS Byte of the count value at the time of the read.

Whatever the timer mode used (input capture, output compare, One Pulse mo de or P WM m ode) an overflow occurs when the counter rolls over from FFFFh to 0000h then:

– The TOF bit of the SR register is set. – A timer interrupt is generated if:

– TOIE bit of the CR1 register is set and – I bit of the CC register is cleared.

If one of these cond itions is false, the interrupt remains pending to be issued as soon as they are both true.

LS Byte

is buffered

Returns the buffered

LS Byte value at t0

Clearing the overflow interrupt request is done in two steps:

1.Reading the SR register while the TOF bit is set.

2.An access (read or write) to the CLR register. Note: The TOF bit is not cleared by accessing the

ACLR register. The advantage of accessing the ACLR register rather than the CLR register is that it allows simultaneous use of the overflow function and reading the free running counter at random times (for example, to measure elapsed time) without the risk of clearing the TOF bit erroneously.

The timer is not affected by WAIT mode. In HALT mode, the counter stops counting until the

mode is exited. Count ing then resumes from the previous count (MCU awakened by an interrupt) or from the reset count (MCU awakened by a Reset).

5.4.3.2 External Clock

The external clock (wh ere available) is selected if CC0=1 and CC1=1 in the CR2 register.

The status of the EXEDG bit in the CR2 register determines the type of level transition on the external clock pin EXTCLK that will trigger the free running counter.

The counter is synchronised with t he falling edge of the internal CPU clock.

A minimum of four falling edges of the CPU clock must occur between two consecutive active edges of the external clock; thus the external clock frequency must be less than a quarter of the CPU clock frequency.

38/109

16-BIT TIMER (Cont’d) Figure 24. Counter Timing Diagram, internal clock divided by 2

CPU CLOCK

INTERNAL RESET

TIMER CLOCK

ST7263

COUNTER REGISTER

TIMER OVERFL OW FLAG (TOF)

FFFD FFFE FFFF 0000 0001 0002 0003

Figure 25. Counter Timing Diagram, internal clock divided by 4

CPU CLOCK

INTERNAL RESET

TIMER CLOCK

COUNTER REGI STER

TIMER OVERFLOW FLAG (TOF)

FFFC FFF D 0000 0001

Figure 26. Counter Timing Diagram, internal clock divided by 8

CPU CLOCK

INTERNAL RESET

TIMER CLOCK

COUNTER REGISTER

TIMER OVERFLOW FLAG (TOF)

FFFC FFFD

0000

Note: The MCU is in reset state when the internal reset signal is high. When it is low, the MCU is running.

39/109

ST7263

16-BIT TIMER (Cont’d)

5.4.3.3 Input Capture

In this section, the index, there are 2 input capture functions in the 16-bit timer.

The two input capture 16-bit registers (IC1R and IC2R) are used to latch the valu e of the free running counter after a transition is detected by the ICAP

pin (see figure 5).

MS Byte LS Byte

ICiR IC

The IC

R register is a read-only register.

The active transition is software programmable

through the IEDG Timing resolution is one count of the free running

counter: (

Procedure:

To use the input capture function, select the following in the CR2 register:

– Select the timer clock (CC[1:0]) (see Table 1). – Select the edge of the active transition on the

ICAP2 pin with the IEDG2 bit (the ICAP2 pin

must be configured as a floating input). And select the following in the CR1 register: – Set the ICI E bit to ge nerat e an in terrupt after an

input capture com ing from e ither the ICAP1 pin

or the ICAP2 pin – Select the edge of the active transition on the

ICAP1 pin with the IEDG1 bit (the ICAP1pin must

be configured as a floating input).

CPU

bit of Control Registers (CRi).

/CC[1:0]).

, may be 1 or 2 because

HR ICiLR

When an input capture occurs: – The ICF – The IC

running counter on the active transition on the ICAP

– A timer interrupt is generated if the ICIE bit i s s e t

and the I bit is cleared in the CC register. Otherwise, the interrupt remains pending until both conditions become true.

Clearing the Input Capture in terrupt request (i.e. clearing the ICF

1. Reading the SR register while the ICF

2. An access (read or write) to the IC

Notes:

1. After reading the IC input capture data is inhibited and ICF never be set until the IC read.

2. The IC counter value which corresponds to the most recent input capture.

3. The 2 input capture functions can be used together even if the timer also uses the 2 output compare functions.

4. In One Pulse mode and PWM mode only the input capture 2 function can be used.

5. The alternate inputs (ICAP1 & ICAP2) are always directly connecte d to the timer. So any transitions on these pins activate the input capture function. Moreover if one of th e ICAP as an input and the s econd one as an output, an interrupt can be generated if the user toggles the output pin and if the ICIE bit is set. This can be avoided if the in put capture function

1).

6. The TOF bit can be used with an interrupt in order to measure events that exce ed the timer range (FFFFh).

bit is set.

R register contains t he val ue of the free

pin (see Figure 6).

bit) is done in two steps:

bit is set.

iLR

HR register, the transfer of

will

LR register is also

R register contains the free running

pin is configured

is disabled by reading the ICiHR (see note

40/109

16-BIT TIMER (Cont’d) Figure 27. Input Capture Block Diagram

ST7263

ICAP1

ICAP2

EDGE DETECT

CIRCUIT2

IC2R Register

16-BIT

EDGE DETECT

CIRCUIT1

IC1R Register

16-BIT FREE RUNNING

COUNTER

Figure 28. Input Capture Timing Diagram

TIMER CLOCK

ICIE

(Control Register 1) CR1

IEDG1

(Status Register) SR

ICF2ICF1 000

(Control Register 2) CR2

IEDG2

CC0

CC1

COUNTER REGISTER

ICAPi PIN

ICAPi FLAG

ICAPi REGISTER

Note: Active edge is rising edge.

FF01 FF02 FF03

FF03

41/109

ST7263

16-BIT TIMER (Cont’d)

5.4.3.4 Output Compare

In this section, the index, there are 2 output compare functions in the 16-bit timer .

This function can be used to control an output waveform or indicate when a period of time has elapsed.

When a match is found bet ween the Output Compare register and the free running counter, the output compare function:

– Assigns pins with a programmable value if the

OCIE bit is set – Sets a flag in the status register – Generates an interrupt if enabled

Two 16-bit registers Output Compare Register 1 (OC1R) and Output Compare Register 2 (OC2R) contain the value to be com pared to the counter register each timer clock cycle.

MS Byte LS Byte

ROC

These registers are readable and writable and are not affected by the timer hardware. A reset event changes the OC

R value to 8000h.

Timing resolution is one count of the free running counter: (

CPU/

CC[1:0]

Procedure:

To use the output compare function, select the following in the CR2 register:

– Set the OC

OCMP

E bit if an output is needed then the

pin is dedicated to the output com pare

signal. – Select the timer clock (CC[1:0]) (see Table 1). And select the following in the CR1 register: – Select the OLVL

bit to applied to the OCMPi pins

after the match occurs. – Set the OC IE bit to generate an interrupt if it is

needed. When a match is found between OCRi register

and CR register: – OCF

bit is set.

, may be 1 or 2 because

HR OCiLR

– The OCMP

pin takes OLVLi bit value (OCMPi

pin latch is forced low during reset).

– A timer interrupt is generated if the OCIE bit is

set in the CR2 register and the I bit is cleared in the CC register (CC).

The OC

R register value required for a specific timing application can be c alcul ated using the following f ormula:

∆t * f

∆ OC

R =

CPU

PRESC

Where:

∆t = Output compare period (in seconds)

= CPU clock frequency (in hertz)

CPU

PRESC

= Timer prescaler factor (2, 4 or 8 de-

pending on CC[1:0] bits, see Table 1)

If the timer clock is an external clock, the formula is:

∆ OC

R = ∆t

* fEXT

Where:

∆t = Output compare period (in seconds)

= External timer clock frequency (in hertz)

EXT

Clearing the output compare interrupt request (i.e. clearing the OCF

1. Reading the SR register while the OCF

set.

2. An access (read or write) to the OC The following procedure is recommended to pre-

vent the OCF it is read and the write to the OC

– Write to the OC

are inhibited).

– Read the SR register (first step of the clearance

of the OCF

– Write to the OC

compare function and clears the OCF

bit) is done by:

bit from being set between the time

R register:

HR register (further compares

bit, which may be already set).

LR register (enables the output

bit is

LR register.

bit).

42/109

16-BIT TIMER (Cont’d) Notes:

1. After a process or write cycle to t he O C

iHR

reg-

ister, the output compare function is inhibited

iLR

until the OC

2. If the OC general I/O port and the OLVL

E bit is not set, the OCMPi pin is a

bit will not appear when a match is f ound but an interrupt could be generated if the OCIE bit is set.

3. When the timer clock is f OCMP

are set while the counter value equals

the OC

R register value (see Figure 8). This

/2, OCFi and

CPU

behaviour is the same in OPM or PWM mode. When the timer clock is f external clock mode, O CF while the counter value equals the OC

/4, f

CPU

and OCMPi are set

CPU

/8 or in

R regis-

ter value plus 1 (see Figure 9).

4. The output compare functions can be used both for generating external events on the OCMP pins even if the input capture mode is also used.

5. The value in the 16-bit OC

bit should be changed after each suc-

OLV

R register and the

cessful comparison in order to control an output waveform or establish a new elapsed timeout.

Forced Compare Output capabili ty

When the FOLV

bit is set by software, the OLVL bit is copied to the OCMPi pin. Th e OLVi bit has to be toggled in ord er to t oggle th e OCMP it is enabled (OC

E bit=1). The OCFi bit is then not set by hardware, and thus no interrupt request is generated.

FOLVL

bits have no effect in either One-Pulse

mode or PWM mode.

ST7263

pin when

Figure 29. Output Compare Block Diagram

16 BIT FREE RUNNING

COUNTER

16-bit

OUTPUT COMPARE

CIRCUIT

16-bit

OC1R Register

16-bit

OC2R Register

OC1E CC0CC1

OC2E

(Control Register 2) CR2

(Control Register 1) CR1

FOLV2 FOLV1

(Status Register) SR

OLVL1OLVL2OCIE

000OCF2OCF1

Latch

OCMP1

OCMP2

43/109

ST7263

16-BIT TIMER (Cont’d) Figure 30. Output Compare Timing Diagram, f

INTERNAL CPU CLOC K

TIMER CLOCK

TIMER

CPU

COUNTER REGISTER

OUTPUT COMPARE REGISTER

OUTPUT COMPARE FLAG

OCMP

(OCRi)

(OCFi)

PIN (OLVLi=1)

Figure 31. Output Compare Timing Diagram, f

INTERNAL CPU CLOC K

TIMER CLOCK

COUNTER REGISTER

OUTPUT COMPARE REGISTER

COMPARE REGISTER

OUTPUT COMPARE FLAG

(OCRi)

LATCH

(OCFi)

2ED0 2ED1 2ED2

TIMER

CPU

2ED0 2ED 1 2ED 2

2ED3

2ED42ECF

44/109

OCMPi PIN (OLVLi=1)

16-BIT TIMER (Cont’d)

5.4.3.5 One Pulse Mode

One Pulse mode enables the generation of a pulse when an external event occurs. This mode is selected via the OPM bit in the CR2 register.

The One Pulse mode uses the Input Capture1 function and the Output Compare1 function.

Procedure:

To use One Pulse mode:

1. Load the OC1R register with the value corresponding to the length of the pulse (see the formula in the opposite column).

2. Select the following in the CR1 register: – Using the OLVL1 bit, select the level to be ap-

plied to the OCMP1 pin after the pulse.

– Using the OLVL2 bit, select the level to be ap-

plied to the OCMP1 pin during the pulse.

– Select the edge of the a ctive trans ition o n th e

ICAP1 pin with the IEDG1 bit

(the ICAP1 pin

must be configured as floating input).

3. Select the following in the CR2 register: – Set the OC1E bit, the OCMP1 pin is then ded-

icated to the Output Compare 1 function. – Set the OPM bit. – Select the timer clock CC[1:0] (see Table 1).

ST7263

Clearing the Input Capture in terrupt request (i.e. clearing the ICF

1. Reading the SR register while the ICF

2. An access (read or write) to the IC The OC1R register value required for a specific

timing application can be calculated usi ng the following formula:

Where: t = Pulse period (in seconds)

= CPU clock frequency (in hertz)

CPU

PRESC

= Timer prescaler factor (2, 4 or 8 depend-

If the timer clock is an external clock the formula is:

Wher e: t = Pulse period (in seconds) f

= External timer clock frequency (in hertz)

EXT

When the value of the counter is equal to the value of the contents of t he OC1R register, the OLV L1 bit is output on the OCMP1 pin (see Figure 10).

bit) is done in two steps:

bit is set.

iLR

R Value =

CPU

PRESC

- 5

ing on the CC[1:0] bits, see Table 1)

OCiR = t

* fEXT

-5

One Pulse mode cycle

When

event occurs

on ICAP1

OCMP1 = OLVL2

Counter is reset

to FFFCh

ICF1 bit is set

When Counter = OC1R

OCMP1 = OLVL1

Then, on a valid event on the ICAP1 pin, the counter is initialized to FFFCh and the OLVL2 bit is loaded on the OCMP1 pin, th e ICF1 bit is set and the value FFFDh is loaded in the IC1R register.

Because the ICF1 bit is set when an active edge occurs, an interrupt can be generated if the ICIE bit is set.

Notes:

1. The OCF1 bit cannot be set by hardware in One Pulse mode but the OCF2 bit can generate an Output Compare interrupt.

2. When the Pulse Width Modulation (PWM ) and One Pulse mode (OPM) bits are both set, the PWM mode is the only active one.

3. If OLVL1=OLVL2 a continuous signal will be seen on the OCMP1 pin.

4. The ICAP1 pin can not be used to perform input capture. The ICAP2 pin can be used t o perfo rm input capture (ICF2 can be set and IC2R can be loaded) but the user must take care that the counter is reset each time a valid edge o ccurs on the ICAP1 pin and ICF1 can also generates interrupt if ICIE is set.

5. When One Pulse m ode is used OC1R is dedicated to this mode. Nevertheless OC2R and OCF2 can be used to indicate that a period of time has elapsed but cannot generate an output waveform because the OLVL2 level is dedicated to One Pulse mode.

45/109

ST7263

16-BIT TIMER (Cont’d) Figure 32. One Pulse Mode Timing Example

COUNTER

ICAP1

OCMP1

FFFC FFFD FFFE 2ED0 2ED1 2ED2

OLVL2

compare1

Note: IEDG1=1, OC1R=2ED 0h, OLV L1=0, OLVL2=1

Figure 33. P ul se Wi dt h M odulation Mode Timing Example

COUNTER

OCMP1

FFFC FFFD FFFE

34E2

OLVL2

2ED0 2ED1 2ED2

compare2 compare1 compare2

FFFC FFFD

2ED3

OLVL2OLVL1

34E2 FFFC

OLVL2OLVL1

Note: OC1R=2ED0h, OC2R=34E2, OLVL1=0, OLVL2= 1

46/109

16-BIT TIMER (Cont’d)

5.4.3.6 Pulse Width Modulation Mode

Pulse Width Modulation (PWM) mode enables the generation of a signal wi th a frequency a nd pul se length determined by the value of the OC1R and OC2R registers.

The Pulse Width Modulation mode uses the com plete Output Compare 1 funct ion plus the OC2R register, and so these functions cannot be used when the PWM mode is activated.

Procedure

To use Pulse Width Modulation mode:

1. Load the OC2R register with the value corresponding to the period of the signal using the formula in the opposite column.

2. Load the OC1R register with the value corresponding to the period of the p ulse i f OLVL1= 0 and OLVL2=1, using the formula in the opposite column.

3. Select the following in the CR1 register: – Using the OLVL1 bit, select the level to be ap-

plied to the OCMP1 pin after a successful comparison with OC1R register.

– Using the OLVL2 bit, select the level to be ap-

plied to the OCMP1 pin after a successful comparison with OC2R register.

4. Select the following in the CR2 register: – Set OC1E bit: the OCMP1 pin is then dedicat-

ed to the output compare 1 function. – Set the PWM bit. – Select the timer clock (CC[1:0]) (see Table 1).

If OLVL1=1 and O LVL2=0, t he length of t he pos itive pulse is the difference between the OC2R and OC1R registers.

If OLVL1=OLVL2 a c ontinuous s ign al will be seen on the OCMP1 pin.

Pulse Width Modulation cycle

When

Counter

OCMP1 = OLVL1

= OC1R

When

Counter = OC2R

OCMP1 = OLVL 2

Counter is reset

to FFFCh

ST7263

The OC ing application can be c alcul ated using the following f ormula:

Where: t = Signal or pulse period (in seconds)

CPU

PRESC

If the timer clock is an external clock the formula is:

Wher e: t = Signal or pulse period (in seconds) f

EXT

The Output Compare 2 event causes the counter to be initialized to FFFCh (See Figure 11)

Notes:

1. After a write instruction to the OC

2. The OCF1 and OCF2 bits cannot be set by

3. The ICF1 bit is set by hardware when the coun-

4. In PWM mod e the ICAP1 pin can not be used

5. When the Pulse Width Modulation (PWM ) and

R register value required for a specific tim-

R Value =

CPU

PRESC

- 5

= CPU clock frequency (in hertz)

= Timer prescaler factor (2, 4 or 8 depend-

ing on CC[1:0] bits, see Table 1)

OCiR = t

* fEXT

-5

= External timer clock frequency (in hertz)

HR register,

the output compare function is inhibited until the

LR register is also written.

hardware in PWM mode, therefore the Output Compare interrupt is inhibited.

ter reaches the OC2R value and can produce a timer interrupt if the ICIE bit is set and the I bit is cleared.

to perform input capture because it is disconnected from the timer. The ICAP2 pin can be used to perform input capture (ICF2 can be set and IC2R can be loaded) but the user must take care that the counter is reset after each period and ICF1 can also ge nerate an interrupt if ICIE is set.

One Pulse mode (OPM) bits are both set, the PWM mode is the only active one.

ICF1 bit is set

47/109

ST7263

16-BIT TIMER (Cont’d)

5.4.4 Low Power Modes

Mode Description

WAIT

HALT

5.4.5 Interrupts

Input Capture 1 event/Counter reset in PWM mode ICF1 Input Capture 2 event ICF2 Yes No Output Compare 1 event (not available in PWM mode) OCF1 Output Compare 2 event (not available in PWM mode) OCF2 Yes No Timer Overflow event TOF TOIE Yes No

No effect on 16-bit Timer. Timer interrupts cause the device to exit from WAIT mode.

16-bit Timer registers are frozen. In HALT mode, the counter stops counting until Halt mode is exited. Counting resumes from the previous

count when the MCU is woken up by an interrupt with “exit from HALT mode” capability or from the counter reset value when the MCU is woken up by a RESET.

If an input capture event occurs on the ICAP ly, when the MCU is woken up by an interrupt with “exit from HALT mode” capability, the ICF the counter value present when exiting from HALT mode is captured into the IC

Interrupt Event

pin, the input capture detection circuitry is armed. Consequent-

bit is set, and

R register.

Event

Flag

Enable

Control

Bit

ICIE

OCIE

Exit

from

Wait

Yes No

Exit

from

Halt

Note: The 16-bit Timer interrupt ev ents are co nnecte d to the same inte rrupt vector (see In terrupts chap-

ter). These events generate an interrupt if the correspo nding Enable Control Bit is set and the interrupt mask in the CC register is reset (RIM instruction).

5.4.6 Summary of Timer modes

MODES

Input Capture (1 and/or 2) Yes Yes Yes Yes Output Compare (1 and/or 2) Yes Yes Yes Yes One Pulse mode No Not Recommended PWM Mode No Not Recommended

See note 4 in Section 0.1.3.5 One Puls e Mode

See note 5 in Section 0.1.3.5 One Puls e Mode

See note 4 in Section 0.1.3.6 Pulse Wi dth Modula tion Mode

Input Capture 1 Input Capture 2 Output Compare 1 Output Compare 2

AVAILABLE RESO URC ES

No Partially No No

48/109

16-BIT TIMER (Cont’d)

5.4.7 Register Description

Each Timer is associated with three control and status registers, and with six pairs of data registers (16-bit values) relating to the two input captures, the two output compares, the count er and the a lternate counter.

ST7263

Bit 4 = FOLV2 This bit is set and cleared by software. 0: No effect on the OCMP2 pin. 1:Forces the OLVL2 bit to be copied to the

OCMP2 pin, if the OC 2E bit is set and even if there is no successful compariso n.

Forced Output Compare 2.

CONTROL REGISTER 1 (CR1)

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

ICIE OCIE TOIE FOLV2 FOLV1 OLVL2 IEDG1 OLVL1

Bit 3 = FOLV1 This bit is set and cleared by software. 0: No effect on the OCMP1 pin. 1: Forces OLVL1 to be copied to the OCMP1 pin, if

the OC1E bit is set and e ven if there i s no successful comparison.

Bit 2 = OLVL2

Bit 7 = ICIE

Input Capture Interrupt Enable.

0: Interrupt is inhibited. 1: A timer interrupt is generated whenever the

ICF1 or ICF2 bit of the SR register is set.

This bit is copied to the OCMP2 pin whenev er a successful compa rison occurs with t h e OC2R reg ister and OCxE is set in the CR2 register. This value is copied to the OCMP1 pin in One Pulse mode and Pulse Width Modulation mode.

Bit 1 = IEDG1

Bit 6 = OCIE 0: Interrupt is inhibited. 1: A timer interrupt is generated whenever the

OCF1 or OCF2 bit of the SR register is set.

Bit 5 = TOIE 0: Interrupt is inhibited. 1: A timer interrupt is enabled whenever the TOF

bit of the SR register is set.

Output Compare Interrupt Enable.

Timer Overflow Interrupt Enable.

This bit determines wh ich type of level transition on the ICAP1 pin will trigger the capture. 0: A falling edge triggers the capture. 1: A rising edge triggers the capture.

Bit 0 = OLVL1 The OLVL1 bi t is c opied to t he OCMP1 pin whenever a successful comparison occurs with the OC1R register and the OC 1E bit is s et in the CR2

Forced Output Compare 1.

Output Level 2.

Input Edge 1.

Output Level 1.

49/109

ST7263

16-BIT TIMER (Cont’d) CONTROL REGISTER 2 (CR2)

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

OC1E OC2E OPM PWM CC1 CC0 IEDG2 EXEDG

Bit 4 = PWM 0: PWM mode is not active. 1: PWM mode is active, the OCMP 1 pin outputs a

programmable cyclic signal; the length of the pulse depends on the value of OC1R register; the period depends on the value of OC2R register.

Pulse Width Modulation.

Bit 7 = OC1E

Output Compare 1 Pin Enable.

This bit is used only to outp ut the signal from the timer on the OCMP1 pin (OLV1 in Output Compare mode, both OLV1 and OLV2 in PWM and one-pulse mode). Whatever the value of the OC1E bit, the internal Output Compare 1 function of the timer remains active. 0: OCMP1 pin alternate f unction disa bled (I/O pin

free for general-purpose I/O).

1: OCMP1 pin alternate function enabled.

Bit 6 = OC2E

Output Compare 2 Pin Enable.

This bit is used only to outp ut the signal from the timer on the OCMP2 pin (OLV2 in Output Compare mode). Whatever the value of the OC2E bit, the internal Output Compare 2 function of the timer remains active. 0: OCMP2 pin alternate f unction disa bled (I/O pin

free for general-purpose I/O).

1: OCMP2 pin alternate function enabled.

Bit 5 = OPM

One Pulse mode.

0: One Pulse mode is not active. 1: One Pulse mode is active, the ICAP1 pin can be

used to trigger one pulse on the OCMP1 pin; the active transition is g iven by the I EDG1 bit. Th e length of the generated pulse depends on the contents of the OC1R register.

Bits 3:2 = CC[1:0]

Clock Control.

The timer clock mode depends on these bits:

Table 16. Clock Control Bits

Timer Clock CC1 CC 0

/ 4 0 0

CPU

/ 2 0 1

CPU

/ 8 1 0

CPU

External Clock (where

available)

Note: If the external clock pin is not available, programming the external clock configuration stops the counter.

Bit 1 = IEDG2

Input Edge 2.

This bit determines wh ich type of level transition on the ICAP2 pin will trigger the capture. 0: A falling edge triggers the capture. 1: A rising edge triggers the capture.

Bit 0 = EXEDG

External Clock Edge.

This bit determines wh ich type of level transition on the external clock pin (EXTCLK) will trigger the counter register. 0: A falling edge triggers the counter register. 1: A rising edge triggers the counter register.

50/109

16-BIT TIMER (Cont’d) STATUS REGISTER (SR)

Read Only Reset Value: 0000 0000 (00h) The three least significant bits are not used.

ICF1 OCF1 TOF ICF2 OCF2 0 0 0

INPUT CAPTURE 1 HIGH REGISTER (IC1HR)

Read Only Reset Value: Undefined

This is an 8-bit read only register that contains the high part of the counter value (transferred by the input capture 1 event).

ST7263

Bit 7 = ICF1

Input Capture Flag 1.

0: No input capture (reset value). 1: An input capture has occurred on the ICAP1 pin

or the counter has reached th e OC2R value in PWM mode. To clear this bit, first read the SR register, then read or write the lo w byte of the IC1R (IC1LR) register.

Bit 6 = OCF1

Output Compare Flag 1.

0: No match (reset value). 1: The content of the free running counter matches

the content of the OC1R regis ter. To clear this bit, first read the SR register, then re ad or write the low byte of the OC1R (OC1LR) register.

Bit 5 = TOF

Timer Overflow Flag.

0: No timer overflow (reset value). 1: The free running counter has rolled over from

FFFFh to 0000h. To clear this bit, first read the SR register, then read or write t he low byte of the CR (CLR) register.

Note: Reading or writing the ACLR register does not clear TOF.

Bit 4 = ICF2

Input Capture Flag 2.

0: No input capture (reset value). 1: An input capture has occurred on the ICAP2

pin. To clear this bit, first read the SR register, then read or write the low byte of the IC2R (IC2LR) register.

Bit 3 = OCF2

Output Compare Flag 2.

0: No match (reset value). 1: The content of the free running counter matches

the content of the OC2R regis ter. To clear this bit, first read the SR register, then re ad or write the low byte of the OC2R (OC2LR) register.

Bit 2-0 = Reserved, forced by hardware to 0.

MSB LSB

INPUT CAPTURE 1 LOW REGISTER (IC1LR)

Read Only Reset Value: Undefined

This is an 8-bit read only register that contains the low part of the counter value (transferred by the input capture 1 event).

MSB LSB

OUTPUT COMPARE 1 HIGH REGISTER (OC1HR)

Read/Write Reset Value: 1000 0000 (80h)

This is an 8-bit re gister tha t co ntains t he hi gh part of the value to be compared to the CHR register.

MSB LSB

OUTPUT COMPARE 1 LOW REGISTER (OC1LR)

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

This is an 8-bit register that contains the low part of the value to be compared to the CLR register.

MSB LSB

51/109

ST7263

16-BIT TIMER (Cont’d) OUTPUT COMPARE 2 HIGH REGISTER

(OC2HR)

Read/Write Reset Value: 1000 0000 (80h)

This is an 8-bit register that cont ains the high part of the value to be compared to the CHR register.

ALTERNATE COUNTER HIGH REGISTER (ACHR)

Read Only Reset Value: 1111 1111 (FFh)

This is an 8-bit re gister tha t co ntains t he hi gh part of the counter value.

MSB LSB

OUTPUT COMPARE 2 LOW REGISTER (OC2LR)

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

This is an 8-bit register that contains the low part of the value to be compared to the CLR register.

MSB LSB

ALTERNATE COUNTER LOW REGISTER (ACLR)

Read Only Reset Value: 1111 1100 (FCh)

This is an 8-bit register that contains the low part of the counter value. A write to this register resets the counter. An access to this register after an access to SR register does no t clear the TOF bit i n SR register.

MSB LSB

COUNTER HIGH REGISTER (CHR)

MSB LSB

Read Only Reset Value: 1111 1111 (FFh)

This is an 8-bit register that cont ains the high part of the counter value.

INPUT CAPTURE 2 HIGH REGISTER (IC2HR) Read Only

Reset Value: Undefined This is an 8-bit read only register that contains the

high part of the counter value (transferred by the

MSB LSB

Input Capture 2 event).

COUNTER LOW REGISTER (CLR)

MSB LSB

Read Only Reset Value: 1111 1100 (FCh)

This is an 8-bit register that contains the low part of the counter value. A write to this register resets the counter. An access to this register after accessing the SR register clears the TOF bit.

INPUT CAPTURE 2 LOW REGISTER (IC2LR)

Read Only Reset Value: Undefined

This is an 8-bit read only register that contains the low part of the counter value (transferred by the Input Capture 2 event).

MSB LSB

52/109

MSB LSB

16-BIT TIMER (Cont’d) Table 17. 16-Bit Timer Register Map and Reset Values

Address

(Hex.)

Label

CR2

Reset Value

CR1

Reset Value

IC1HR

Reset Value

IC1LR

Reset Value

OC1HR

Reset Value

OC1LR

Reset Value

CHR

Reset Value

CLR

Reset Value

ACHR

Reset Value

ACLR

Reset Value

IC2HR

Reset Value

IC2LR

Reset Value

OC2HR

Reset Value

OC2LR

Reset Value

76543210

OC1E0OC2E

ICIE

ICF1

MSB LSB

MSB LSB MSB

MSB

MSB LSB

MSB LSB MSB

MSB

OCIE

OCF1

OPM

TOIE0FOLV20FOLV10OLVL20IEDG10OLVL1

TOF

PWM

ICF2

CC1

OCF2

CC0

0 0

ST7263

IEDG20EXEDG

0 0 0

LSB

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ST7263

5.5 SERIAL COMMUNICATIONS INTERFACE (SCI)

5.5.1 Introd uction

The Serial Communications Interface (SCI) offers a flexible means of full-duplex data exchange with external equipment requiring an indust ry stand ard NRZ asynchronous serial data format.

5.5.2 Main Features

■ Full duplex, asynchronous communi cations

■ NRZ standard format (Mark/Space)

■ Independently programmable transmit and

receive baud rates up to 250K baud.

■ Programmable data word length (8 or 9 bits)

■ Receive buffer full, Transmit buffer empty and

End of Transmission flags

■ Two receiver wake-up modes:

– Address bit (MSB) – Idle line

■ Muting function for multiprocessor configurations

■ Separate enable bits for Transmitter and

Receiver

■ Three error detection flags:

– Overrun error – Noise error – Frame error

■ Five interrupt sources with flags:

– Transmit data register empty – Transmission complete – Receive data register full – Idle line received – Overrun error detected

5.5.3 General Description

The interface is externally connected to another device by two pins (see Figure 1):

– TDO: Transmit Data Output. When the transmit-

ter is disabled, the output pin returns to its I/O port configuration. When the transmitter is enabled and nothing is to be transmitted, the TDO pin is at high level.

– RDI: Receive Data Input is the serial data input.

Oversampling techniques are used for data recovery by discriminating between valid incoming data and noise.

Through this pins, serial data is transmitted and received as frames comprising:

– An Idle Line prior to transmission or reception – A start bit – A data word (8 or 9 bits) least significant bit first – A Stop bit indicating that the frame is complete.

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SERIAL COMMUNICATIONS INTERFACE (Cont’d) Figure 34. SCI Block Diagram

ST7263

TDO

RDI

Write

Transmit Data Register (TDR)

Transmit Shift Register

TRANSMIT

CONTROL

CR2

WAKE

UNIT

SBKRWURETEILIERIETCIETIE

Read

Received Data Register (RDR)

Received Shift Register

T8 - M

(Data Register) DR

WAKE

RECEIVER

CONTROL

TDRE TC RDRF

IDLE OR NF FE -

CR1

RECEIVER

CLOCK

CPU

SCI

INTERRUPT

CONTROL

TRANSMITTER

CLOCK

/16

/PR

Transmitter Rate

Control

SCP1

SCT2

SCP0

BAUD RATE GENER ATOR

BRR

SCT1SCT0SCR2SCR1SCR0

Receiver Rate Control

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ST7263

SERIAL COMMUNICATIONS INTERFACE (Cont’d)

5.5.4 Functional Description

The block diagram of the S erial Control Interface, is shown in Figure 1. It contains 4 dedicated registers:

– Two control registers (CR1 & CR2) – A status register (SR) – A baud rate register (BRR) Refer to the register descriptions in Section 0.1.7

for the definitions of each bit.

5.5.4.1 Serial Data Format

Word length may be selected as being either 8 or 9 bits by programming the M bit in the CR1 register (see Figure 1).

Figure 35. Word Length Programming

The TDO pin is in low state during the start bit. The TDO pin is in high state during the stop bit. An Idle character is interpreted as an entire frame

of “1”s followed by t he start bit of the n ext frame which contains data.

A Break character is interpreted on receiving “0”s for some multiple of the frame period. At the end of the last break frame the transm itter inserts an extra “1” bit to acknowledge the start bit.

Transmission and reception are driven by their own baud rate generator.

9-bit Word length (M bit is set)

Data Frame

Start

Bit

Bit0

Bit1

Bit2

Bit3

Idle Frame

Break Frame

8-bit Word length (M bit is reset)

Data Frame

Start

Bit

Bit0

Bit1

Bit2

Bit3

Idle Frame

Break Fr ame

Bit4

Bit5

Bit5 Bit6

Bit6

Possible

Parity

Bit7

Possible

Parity

Bit

Bit7

Bit

Bit8

Stop

Bit

Next Data Frame

Next Start

Stop

Bit

Start

Bit

Extra

’1’

Next Data Frame

Next Start

Bit

Start

Bit

Start

Extra

’1’

Bit

Start

Bit

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SERIAL COMMUNICATIONS INTERFACE (Cont’d)

5.5.4.2 Transmitter

The transmitter can send data words of either 8 or 9 bits depending on the M bit status. W hen the M bit is set, word length is 9 bits and the 9th bit (the MSB) has to be stored in the T8 bit in the CR1 register.

Character Transmission

During an SCI transmission, data shifts out least significant bit first on t he TDO pin. In this m ode, the DR register consists of a buffer (TDR) between the internal bus and the transmit shift register (see Figure 1).

Procedure

– Sele ct the M bit to define the word length. – Select the desired baud rate using the BRR reg-

ister.

– Set the TE bit to assign the TDO pin to the alter-

nate function and to send a idle frame as first transmission.

– Acc ess the SR register and write the data to

send in the DR register (this sequence clears the TDRE bit). Repeat this sequence for each data to be transmitted.

The following software sequence is always to clear the TDRE bit:

1. An access to the SR register

2. A write to the DR register The TDRE bit is set by hardware and it indicates

that: – The TDR register is empty. – The dat a transfer is beginning. – The next data can be written in the DR register

without overwriting the previous data.

This flag generates an interrupt if the TIE bit is set and the I bit is cleared in the CC register.

When a transmission is taking place, a write instruction to the DR register stores the data in the TDR register which is copied in the shift register at the end of the current transmission.

When no transmission is ta king place, a write instruction to the DR register places the data directly in the shift register, the data transmission starts, and the TDRE bit is immediately set.

ST7263

When a frame trans mission is com plete (after the stop bit or after the break frame) the TC bit is set and an interrupt is generated if the TCIE is set and the I bit is cleared in the CC register.

The following software sequence is always to clear the TC bit:

1. An access to the SR register

2. A write to the DR register Note: The TDRE and TC bits are cleared by the

same software sequence.

Break Characters

Setting the SBK bit loads the shift register with a break character. The break frame length depends on the M bit (see Figure 2).

As long as the SBK bit is set, the SCI sends break frames to the T DO pin. After clearing this bit by software, the SCI inserts a logic 1 bit at the end of the last break frame to guarantee the recognition of the start bit of the next frame.

Idle Characters

Setting the TE bit drives the SCI t o send an idle frame before the first data frame.

Clearing and then setting the TE bit during a transmission sends an idle frame after the current word.

Note: Resetting and setting t he TE bit causes t he data in the TDR register to be lost . Therefore the best time to toggle the TE bit is when the TDRE bit is set, i.e. before writing the next byte in the DR.

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ST7263

SERIAL COMMUNICATIONS INTERFACE (Cont’d)

5.5.4.3 Receiver

The SCI can receive data words of either 8 or 9 bits. When the M bit i s set, word length is 9 bits and the MSB is stored in the R8 bit in the CR1 register.

Character reception

During a SCI reception, data shifts in least significant bit first through the RDI pin. In this mode, the DR register consists of a buffer (RDR) between the internal bus and the received shift register (see Figure 1).

Procedure

– Sele ct the M bit to define the word length. – Select the desired baud rate using the BRR reg-

ister.

– Set the RE bit to enable the receiverto begin

searching for a start bit. When a character is received: – The RDRF bit is set. It indicates that the content

of the shift register is transferred to the RDR. – An interrupt is generated if the RIE bit is set and

the I bit is cleared in the CC register. – The error flags can be set if a frame error, noise

or an overrun error has been detected during re-

ception. Clearing the RDRF bit is performed by the following

software sequence done by:

1. An access to the SR register

2. A read to the DR register. The RDRF bit must be cleared before the end of t he

reception of the next character to avoid an overrun error.

Break Character

When a break charact er is rec eived, t he S CI handles it as a framing error.

Idle Character

When a idle frame is detected, there is the same procedure as a data received character plus an interrupt if the ILIE bit is set and the I bit is cleared in the CC register.

Overrun Error

An overrun error occurs when a character is received when RDRF has not been reset. Data can not be transferred from the shift register to the TDR register as long as the RDRF bit is not cleared.

When a overrun error occurs: – The OR bit is set. – The RDR content will not be lost. – The shift register will be overwritten. – An interrupt is generated if the RIE bit is set and

the I bit is cleared in the CC register.

The OR bit is reset by an access to the SR register followed by a DR register read operation.

Noise Error

Oversampling techniques are used for data recovery by discriminating between v alid inc oming dat a and noise.

When noise is detected in a frame: – The NF is set at the rising edge of the RDRF bit. – Data is transferred from the Shift register to the

DR register.

– No interrupt is generated. However this bit rises

at the same time as the RDRF bit which itself generates an interrupt.

The NF bit is reset by a SR register read operation followed by a DR register read operation.

Framing E rror

A framing error is detected when: – The stop bit is not recognized on reception at the

expected time, following either a de-synchroni-

zation or excessive noise. – A break is received. When the framing error is detected: – The FE bit is set by hardware – Data is transferred from the Shift register to the

DR register. – No interrupt is generated. However this bit rises

at the same time as the RDRF bit which itself

generates an interrupt. The FE bit is reset by a SR register read operation

followed by a DR register read operation.

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SERIAL COMMUNICATIONS INTERFACE (Cont’d)

5.5.4.4 Baud Rate Generation

The baud rates for the receiver and transmitter (Rx and Tx) are set independent ly and calculated as follo ws:

(32

CPU

PR)*RR

Tx =

(32

CPU

PR)*TR

Rx =

with: PR = 1, 3, 4 or 13 (see SCP0 & SCP1 bits) TR = 1, 2, 4, 8, 16, 32, 64,128 (see SCT0, SCT1 & SCT2 bit s ) RR = 1, 2, 4, 8, 16, 32, 64,128 (see SCR0,SCR1 & SCR2 bits) All these bits are in the BRR register. Example: If f

is 8 MHz and if PR=13 and

CPU

TR=RR=1, the transmit and receive baud rates are 19200 bauds.

Note: The baud rate registers MUST NOT be changed while the transmitter or the receiver is enabled.

5.5.4.5 Receiver Muting and Wake-up Feature

In multiprocessor configurations it is often desirable that only the intended message recipient

ST7263

should actively receive the f ull me ssag e cont ents, thus reducing redundant SCI service overhead for all non addressed receivers.

The non addressed devices may be placed in sleep mode by means of the muting function.

Setting the RWU b it by software puts the SCI in sleep mode:

All the reception status bits can not be set. All the receive interrupt are inhibited. A muted receiver may be awakened by one of the

following two ways: – by Idle Line detection if the WAKE bit is reset, – by Address Mark detection if the WAKE bit is set. The Receiver wakes-up by Idle Line detection

when the Receive line has recognised an Idle Frame. Then the RWU bit is reset by hardware but the IDLE bit is not set.

The Receiver wakes-up by Address Mark detection when it received a “1” as the most significant bit of a word, thus indicating that the mess age is an address. The reception of this particular word wakes up the receiver, resets the RWU bit and sets the RDRF bit, which allows the receiver to receive this word normally and to use it as an address word.

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ST7263

SERIAL COMMUNICATIONS INTERFACE (Cont’d)

5.5.5 Low Power Modes Mode Description

WAIT

HALT

5.5.6 Interrupts

Transmit Data Register Empty TDRE TIE Yes No Transmission Complete TC TCIE Yes No Received Data Ready to be Read RDRF Overrrun Error Detected OR Yes No Idle Line Detected IDLE ILIE Yes No

No effect on SCI. SCI interrupts exit from Wait mode.

SCI registers are frozen.

In Halt mode, the SCI stops transmitting/receiving until Halt mode is exited.

Enable

Control

Bit

RIE

Interrupt Event

Event

Flag

Exit

from

Wait

Yes No

Exit

from

Halt

The SCI interrupt events are connected to the same interrupt vector (see Interrupts chapter).

These events generate an interrupt if the corresponding Enable Control Bit is set and the inter-

rupt mask in the CC register is reset (RIM instruction).

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SERIAL COMMUNICATIONS INTERFACE (Cont’d)

5.5.7 Register Description

STATUS REGISTER (SR)

Read Only

Note: T he IDLE bit will not be set again unt il the RDRF bit has been set itself (i.e. a new idle line occurs). This bit is not set by an idle line when the receiver wakes up from wake-up mode.

Reset Value: 1100 0000 (C0h)

TDRE TC RDRF IDLE O R NF FE

Bit 3 = OR This bit is set by hardware when the word currently being received in the s hift register is ready to be transferred into the RDR register while RDRF=1.

Overrun error.

An interrupt is generate d i f RIE=1 in th e CR2 reg-

Bit 7 = TDRE

Transmit data register empty.

This bit is set by hardware when the content of the TDR register has been transferred into the shift register. An interrupt is generated if TIE =1 in the CR2 register. It is cleared by a software sequence

ister. It is cleared by hardware when RE=0 by a software sequence (an access to the SR register followed by a read to the DR register). 0: No Overrun error 1: Overrun error is detected

(an access to the SR register followed by a write to the DR register). 0: Data is not transferred to the shift register 1: Data is transferred to the shift register

Note: data will not be transferred to the shift register as long as the TDRE bit is not reset.

Note: When this bit is set the RDR register content will not be lost but the shift register will be overwritten.

Bit 2 = NF

Noise flag.

This bit is set by hardware when noise is detected on a received frame. It is cleared by hardware

Bit 6 = TC

Transmission complete.

This bit is set by hardware when transmission of a frame containing Data, a Preamble or a Break is complete. An interrupt is generat ed if TCIE=1 in the CR2 register. It is cleared by a software sequence (an access to the SR register followed by a write to the DR register). 0: Transmission is not complete

when RE=0 by a software sequence (an access to the SR register followed by a read to the DR register). 0: No noise is detected 1: Noise is detected

Note: This bit does not generate interrupt as it appears at the same time as the RDRF bit which itself generates an interrupt.

1: Transmission is complete

Bit 5 = R DRF

Received data ready flag.

This bit is set by hardware when the content of the RDR register has been transferred into the DR register. An interrupt is generated if RIE=1 in the CR2 register. It is cleared by hardware when RE=0 or by a software sequence (an access to the SR register followed by a read to the DR register). 0: Data is not received 1: Received data is ready to be read

Bit 1 = FE This bit is set by hardware when a de-synchronization, excessive noise or a b reak character is detected. It is cleared by hardware when RE=0 by a software sequence (an access to the SR register followed by a read to the DR register). 0: No Framing error is detected 1: Framing error or break character is detected

Note: This bit does not generate interrupt as it appears at the same time as the RDRF bit which it-

Framing error.

self generates an interrupt. If the word currently

Bit 4 = IDLE This bit is set by hardware when an Idle Line is detected. An interrupt is generated if ILIE=1 in the

Idle line detect.

being transferred causes both frame error and overrun error, it will be transferred and only the OR bit will be se t.

CR2 register. It is cleared by hardware when RE=0 by a software sequence (an access to the SR register followed by a read to the DR register).

Bit 0 = Reserved, forced by hardware to 0. 0: No Idle Line is detected 1: Idle Line is detected

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ST7263

SERIAL COMMUNICATIONS INTERFACE (Cont’d) CONTROL REGISTER 1 (CR1)

Read/Write Reset Value: Undefined

0: interrupt is inhibited

1: An SCI interrupt is generated whenever TC=1 in

the SR register

Bit 5 = RIE

Receiver interrupt enable

This bit is set and cleared by software.

R8 T8 0 M WAKE 0 0

0: interrupt is inhibited

1: An SCI interrupt is generated whenever OR=1

or RDRF=1 in the SR register

Bit 7 = R8 This bit is used t o store the 9t h bit o f the rec ei ved word when M=1.

Receive data bit 8.

Bit 4 = ILIE

Idle line interrupt enable.

This bit is set and cleared by software.

0: interrupt is inhibited Bit 6 = T8

Transmit data bit 8.

This bit is used to store the 9th bit of the transmit-

1: An SCI interrupt is generated whenever IDLE=1

in the SR register.

ted word when M=1.

Transmitter enable.

Bit 5 = Reserved, forced by hardware to 0.

Bit 3 = TE

This bit enables the transmitter and assigns the

TDO pin to the alternate function. It is set and

cleared by software. Bit 4 = M

Word length.

This bit determines the data length. It is set or cleared by software. 0: 1 Start bit, 8 Data bits, 1 Stop bit 1: 1 Start bit, 9 Data bits, 1 Stop bit

0: Transmitter is disabled, the TDO pin is back to

the I/O port configuration.

1: Transmitter is enabled

Note: During transmission, a “0” pulse on the TE

bit (“0” followed by “1”) sends a preamble after the

current word. Bit 3 = WAKE

This bit determines the SCI Wake-Up method, it is set or cleared by software. 0: Idle Line 1: Address Mark

Wake-Up method.

Bit 2 = RE

Receiver enable.

This bit enables the receiver. It is set and cleared

by software.

0: Receiver is disabled, it resets the RDRF, IDLE,

OR, NF and FE bits of the SR register.

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

1: Receiver is enabled and begins searching for a

start bit.

CONTROL REGISTER 2 (CR2)

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

Bit 1 = RWU

This bit determines if the SCI is in mut e mode or

not. It is set and cleared by so ftware and can be

cleared by hardware when a wake-up sequence is

recognized.

0: Receiver in active mode

Receiver wake-up.

1: Receiver in mute mode

TIE TCIE RIE ILIE TE RE RWU SBK

Send break.

Bit 7 = TIE

Transmitter interrupt enable

. This bit is set and cleared by software. 0: interrupt is inhibited 1: An SCI interrupt is generated whenever

TDRE=1 in the SR register.

Bit 0 = SBK This bit set is used to se nd break characters. It is set and cleared by software. 0: No break character is transmitted 1: Break characters are transmitted

Note: If the SBK bit is set to “1” and then to “0”, the transmitter will send a BREAK word at the end of

Bit 6 = TCIE

Transmission complete interrupt ena-

the current word.

ble

This bit is set and cleared by software.

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SERIAL COMMUNICATIONS INTERFACE (Cont’d) DATA REGISTER (DR)

Read/Write Reset Value: Undefined Contains the Received or Transmitted dat a char-

acter, depending on whether it is read from or written to.

DR7 DR6 DR5 DR4 DR3 DR2 DR1 DR0

The Data register performs a double function (read and write) since it is composed of two reg isters, one for transmission (T DR) and one for recep tion (RDR). The TDR register provides the parallel interface

Bits 5:3 = SCT[2:0] These 3 bits, in conjunction with the SCP1 & SCP0

bits, define the total division applied to the bus clock to yield the transmit rate clock in conventional Baud Rate Generator mode.

TR Dividing Factor SCT2 SCT1 SCT0

1 000 2 001 4 010

8 011 16 100 32 101 64 110

128 1 1 1

SCI Transmitter rate divisor

between the internal bus and the out put shift register (see Figure 1). The RDR register provides the parallel interface between the input shift register and the internal bus (see Figure 1).

BAUD RATE REGISTER (BRR)

Read/Write Reset Value: 00xx xxxx (XXh)

SCP1 SCP0 SCT2 SCT1 SCT0 SCR2 SCR1 SCR0

Bits 7:6= SCP[1:0]

First SCI Prescaler

These 2 prescaling bits allow several standard clock division ranges:

PR Prescaling Factor SCP1 SCP0

100 301 410

13 1 1

Bits 2:0 = SCR[2:0] These 3 bits, in conjunction with the SCP1 & SCP0

bits, define the total division applied to the bus clock to yield the receive rate clock in conventional Baud Rate Generator mode.

RR Dividing Factor SCR2 SCR1 SCR0

1 000

2 001

4 010

8 011 16 100 32 101 64 110

128 1 1 1

SCI Receiver rate divisor.

ST7263

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ST7263

SERIAL COMMUNICATIONS INTERFACE (Cont’d) Table 18. SCI Register Map and Reset Values

Address

(Hex.)

20 SR

21 DR

22 BRR

23 CR1

24 CR2

Label

Reset Value

76543210

TDRE

DR7

SCP1

TIE

DR6

SCP00SCT2xSCT1

TCIE

RDRF0IDLE

DR5

0 0

RIE

DR4

ILIE

DR3

SCT0xSCR2xSCR1xSCR0

WAKE

DR2

0 0

DR1

0 0

RWU

0 0

DR0

0 0

SBK

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5.6 USB INTERFACE (USB)

ST7263

5.6.1 Introd uction

The USB Interface implements a low-speed function interface between the USB and the ST7 microcontroller. It is a highly integrated circuit whi ch includes the transceiver, 3.3 voltage regulator, SIE and DMA. No external components are needed apart from the external pull-up on USBDM for low speed recognition by the USB host. The use of DMA architecture allows the endpoint definition to be completely flexible. Endpoints can be configured by software as in or out.

5.6.2 Main Features

■ USB Specification Version 1.1 Compliant

■ Supports Low-Speed USB Protocol

■ Two or Three Endpoints (i ncludin g default one)

depending on the device (see device feature list and register map)

■ CRC generation/checking, NRZI encoding/

decoding and bit-stuffing

■ USB Suspend/Resume operations

■ DMA Data transfers

■ On-Chip 3.3V Regulator

■ On-Chip USB Transceiver

5.6.3 Functional Description

The block diagram in Fig ure 1 , gives an overview of the USB interface hardware.

For general information on the USB, refer to the

“Universal Serial Bus Specifications” document available at http//:www.usb.org.

Serial Interface Engine

The SIE (Serial Interface Engine) interfaces with the USB, via the transceiver.

The SIE processes tokens, handles data transmission/reception, and handshaking as required by the USB standard. It also perf orms frame formatting, including CRC generation and checking.

Endpoints

The Endpoint registers indicate if the microcontroller is ready to transmit/receive, and how many bytes need to be transmitted.

DMA

When a token for a valid Endpoint is recognized by the USB interface, the related data transfer takes place, using DMA. At the end of the transaction, an interrupt is generated.

Interrupts

By reading the Interrupt S tatus register, application software can know which USB event has occurred.

Figure 36. USB Block Diagram

USBDM

Transceiver

USBDP

3.3V

USBVCC

Voltage Regulator

USBGND

SIE

6 MHz

ENDPOINT

REGISTERS

DMA

INTERRUPT REGISTERS

CPU

Address, data buses and interrupts

MEMORY

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ST7263

USB INTERFACE (Cont’d)

5.6.4 Register Description DMA ADDRESS REGISTER (DMAR)

Read / Write Reset Value: Undefined

DA15 DA14 DA13 DA12 DA11 DA10 DA9 DA8

Bits 7:0=DA[15:8] Software must write the start address of the DMA memory area whose most significant bits are given by DA15-DA6. The remaining 6 address bits are set by hardware. See the description of the I DR register and Figure 2.

DMA address bits 15-8.

INTERRUPT/DMA REGISTER (IDR)

Read / Write Reset Value: xxxx 0000 (x0h)

DA7 DA6 EP1 EP0 CNT3 CNT2 CNT1 CNT0

Bits 7:6 = DA[7:6] Software must reset these bits. See the description of the DMAR register and Figure 2.

Bits 5:4 = EP[1:0] These bits identify the endpoint which required attention. 00: Endpoint 0 01: Endpoint 1 10: Endpoint 2

When a CTR interrupt occurs (see register ISTR) the software should read the EP bits to identify the endpoint which has sent or received a packet.

DMA address bits 7-6.

Endpoint numb er

(read-only).

Figure 37. DMA Buffers

DA15-6,000000

Bits 3:0 = CNT[3:0] This field shows how man y data bytes have b een received during the last data reception.

Note: Not valid for data transmission.

Byte count

(read only).

101111

Endpoint 2 TX

101000 100111

Endpoint 2 RX

100000 011111

Endpoint 1 TX

011000 010111

Endpoint 1 RX

010000 001111

Endpoint 0 TX

001000 000111

Endpoint 0 RX

000000

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USB INTERFACE (Cont’d) PID REGISTER (PIDR)

Read only Reset Value: xx00 0000 (x0h)

ST7263

INTERRUPT STATUS REGISTER (ISTR)

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

TP3TP2000

RX_ SEZ

RXD 0

SUSP DOVR CTR ERR IOVR ESUSP RESET SOF

When an interrupt occurs these bits are set by

Bits 7:6 = TP[3:2] USB token PIDs are encoded in four bits. TP[3:2] correspond to the variable token PID bits 3 & 2.

Token PID bits 3 & 2

hardware. Software must read them to determine the interrupt type and clear them after servicing.

Note : These bits cannot be set by software.

Note: PID bits 1 & 0 have a fixed value of 01.

When a CTR interrupt occurs (see register ISTR) the software should read the TP 3 and TP2 bits to retrieve the PID name of the token received. The USB standard defines TP bits as:

TP3 TP 2 PID Name

00 OUT 10 IN 1 1 SETUP

Bit 7 = SUSP

Suspend mode request

This bit is set by hardware when a constant idle state is present on the bus line for more than 3 ms, indicating a suspend m ode reques t from the U SB bus. The suspend request check is active immediately after each USB reset event and its disabled by hardware when suspend mode is forced (FSUSP bit of CTLR register) until the end of resume sequence.

Bits 5:3 Reserved. Forced by hardware to 0.

DMA over/underrun

Bit 2 = R X_SEZ

Received single-ended zero

This bit indicates the status of the RX_SEZ transceiver output. 0: No SE0 (single-ended zero) state

Bit 6 = DOVR This bit is set by hardware i f the ST7 processor can’t answer a DMA request in time. 0: No over/underrun detected 1: Over/underrun detected

1: USB lines are in SE0 (single-ended zero) state

Bit 1 = RXD

Received data

0: No K-state 1: USB lines are in K-state

This bit indicates the status of the RXD transceiver output (differential receiver output).

Note: If the environment is noisy, the RX_SEZ and RXD bits can be used to secure the application. By interpreting the status, software c an distinguish a valid End Suspend event from a spurious wake-up due to noise on the external USB line. A valid End Suspend is followed by a Resume or Reset sequence. A Resume is indicated by RXD=1, a Reset is indicated by RX_SEZ=1.

Bit 5 = CTR hardware when a correct transfer operation is performed. The type of transfer can be determined by looking at bits TP3-TP2 in register PIDR. The Endpoint on which the transfer was made is identified by bits EP1-EP0 in register IDR. 0: No Correct Transfer detected 1: Correct Transfer detected

Note: A transfer where the device sent a NA K or STALL handshake i s considered not correct (the host only sends ACK handshak es). A transfer is considered correct if there are no errors in the PID and CRC fields, if the DATA0/DATA1 PI D is sent as expected, if there were no data overruns, bit stuffing or framing errors.

Correct Transfer.

This bit is set by

Bit 0 = Reserved. Forced by hardware to 0.

Error.

Bit 4 = ERR This bit is set by hardware whenever one of the errors listed below has occurred: 0: No error detected 1: Timeout, CRC, bit stuffing or nonstandard

framing error detected

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ST7263

USB INTERFACE (Cont’d)

Bit 3 = IOVR This bit is set when hardware tries t o set ERR, or SOF before they have been cleared by software. 0: No overrun detected 1: Overrun detected

Bit 2 = ESUSP This bit is set by hardware when, during suspend mode, activity is detected that wakes the USB i nterface up from suspend mode.

This interrupt is serviced by a specific vector, in order to wake up the ST7 from HALT mode. 0: No End Suspend detected 1: End Suspend detected

Interrupt overrun.

End suspend mode

of each bit, please refer t o the corresponding bit description in ISTR.

CONTROL REGISTER (CTLR)

Read / Write Reset Value: 0000 0110 (06h)

0 0 0 0 RESUME PDWN FSUSP FRES

Bits 7:4 = Reserved. Forced by hardware to 0.

Bit 1 = R ESET

USB reset.

This bit is set by hardware when the USB reset sequence is detected on the bus. 0: No USB reset signal detected 1: USB reset signal detected

Note: The DADDR, EP0RA, EP0RB, EP1RA, EP1RB, EP2RA and EP2RB registers are reset by a USB reset.

Bit 0 = SOF

Start of frame.

This bit is set by hardware when a low-speed SOF indication (keep-alive strobe) is seen o n the USB bus. It is also issued at the end of a resume sequence. 0: No SOF signal detected 1: SOF signal detected

Note: To avoid spurious clearing of some bits, it is recommended to clear them using a load instruction where all bits which must not be altered are set, and all bits to be cleared are reset. Avoid readmodify-write instructions like AND , XOR..

INTERRUPT MASK REGISTER (IMR)

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

Bit 3 = RESUME

Resume

. This bit is set by software to wake-up the Host when the ST7 is in suspend mode. 0: Resume signal not forced 1: Resume signal forced on the USB bus.

Software should clear this bit after the appropriate delay.

Bit 2 = PDWN

Power down

. This bit is set by software to turn off the 3.3V onchip voltage regulator that supplies the external pull-up resistor and the transceiver. 0: Voltage regulator on 1: Voltage regulator off

Note: After turning on the voltage regulator, software should allow at le ast 3 µs for s tabilisation of the power supply before using the USB interface.

Bit 1 = FSUSP

Force suspend mode

. This bit is set by software to enter Suspend mode. The ST7 should also be halted al lowing at least 600 ns before issuing the HALT instruction. 0: Suspend mode inactive 1: Suspend mode active

When the hardware detec ts USB a ctivity, it res ets this bit (it can also be reset by software).

SUSPMDOVRMCTRMERRMIOVRMESU

SPM

RES ETM

SOF

Bit 0 = FRES This bit is set by software to force a reset of the USB interface, just as if a RESET sequence came from the USB.

Force reset.

0: Reset not forced

Bits 7:0 = These bits are mask bits for a ll interrupt condition bits included in the ISTR. Whenever one of the IMR bits is set, if the corresponding ISTR bit is set, and the I bit in the CC register is cleared, an

1: USB interface reset forced. The USB is held in RESET state until software

clears this bit, at which point a “USB-RES ET” interrupt will be generated if enabled.

interrupt request is generated. For an explanation

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USB INTERFACE (Cont’d) DEVICE ADDRESS REGISTER (DADDR)

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

0 ADD6 ADD5 ADD4 ADD3 ADD2 ADD1 ADD0

Bit 6 = DTOG_TX

transfers.

It contains the required value of the toggle bit (0=DATA0, 1=DATA1) for the next transmitted data packet. This bit is set by hardware at the reception of a SETUP P ID. DTOG_TX toggle s only when the transmitter has received the ACK signal

Data Toggle, for tr ansmission

from the USB host. DTOG_TX and also

Bit 7 = Reserved. Forced by hardware to 0.

DTOG_RX (see E PnRB ) are n ormal ly up date d by hardware, at the receipt of a relevant PID. They can be also written by software.

Bits 6:0 = ADD[6:0] Software must write into this register the address

sent by the host during enumeration. Note: This register is also reset when a USB reset

is received from the USB bus or forced through bit FRES in the CTLR register.

ENDPOINT n REGISTER A (EPnRA)

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

ST_

DTOG

OUT

_TX

Device address, 7 bits.

STAT

TBC3TBC2TBC1TBC

_TX1

_TX0

Bits 5:4 = STAT_TX[1:0]

Status bits, for transmis-

sion transfers.

These bits contain the information about the endpoint status, which are listed below:

STAT_TX1 STAT_TX0 Meaning

DISABLED: transmission transfers cannot be executed.

STALL: the endpoint is stalled and all transmission requests result in a STALL handshake.

NAK: the endpoint is naked and all transmission requests result in a NAK handshake.

VALID: this endpoint is enabled for transmission.

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These registers (EP0RA, EP1RA and EP2RA) are used for controlling data transmission. They are also reset by the USB bus reset.

Note: Endpoint 2 an d the EP2RA register are not available on some devices (see device f eature list and register map).

Bit 7 = ST_OUT

Status out.

This bit is set by software to indicate that a status out packet is expec ted: in this case, al l nonzero OUT data transfers on the endpoint are STALLe d instead of being ACKed. When ST _OUT is reset, OUT transactions can have any number of bytes, as needed.

These bits are written by software. Hardware sets the STAT_TX bits to NAK when a correct transfer has occurred (CTR=1) related to a IN or SETUP transaction addressed to this endpoint; this allows the software to prepare the next set of data to be transmitted.

Bits 3:0 = TBC[3:0]

point n.

Transmit byte count for E nd-

Before tr ansmis sion, af ter fillin g the trans mit buf fer, software must write in the TBC field the transmit packet size expressed in bytes (in the range 0-

8).

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USB INTERFACE (Cont’d) ENDPOINT n REGISTER B (EPnRB)

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

CTRL

DTOG

_RX

STAT _RX1

STAT

EA3 EA2 EA1 EA0

_RX0

These registers (EP1RB and EP2RB) are used for controlling data reception on Endpoints 1 and 2. They are also reset by the USB bus reset.

Note: Endpoint 2 an d the EP2RB register are not available on some devices (see device f eature list and register map).

Bit 7 = CTRL

Control.

This bit should be 0. Note: If this bit is 1, the Endpoint is a con trol e nd-

point. (Endpoint 0 is always a control Endpoint, but it is possible to have more than one control Endpoint).

Bit 6 = DTOG_RX

fers

Data toggle, for reception trans-

It contains the expected value of the toggle bit (0=DATA0, 1=DATA1) for the next data packet. This bit is cleared by hardware in the first stage (Setup Stage) of a control transfer (SETUP transactions start always with DATA0 PID). The receiver toggles DTOG_RX o nly if it receives a correct data packet and the packet’s data PID matches the receiver sequence bit.

STAT_RX1 STAT_RX0 Meaning

NAK: the endpoint is na-

ked and all reception requests result in a NAK handshake.

VALID: this endpoint is enabled for reception.

These bits are written by software. Hardware sets the STAT_RX bits to NAK wh en a c orrect transfer has occurred (CTR=1) related to an OUT or SETUP transaction addressed to this endpoint, so the software has the time to elaborate the received data before acknowledging a new transaction.

Bits 3:0 = EA[3:0]

Endpoint address

Software must write in this field the 4-bit address used to identify the transactions directed to this endpoint. Usually EP1RB contains “0001” and EP2RB contains “0010”.

ENDPOINT 0 REGISTER B (EP0RB)

Read / Write Reset Value: 1000 0000 (80h)

DTOGRXSTAT

RX1

STAT

RX0

0000

This register is used for controlling data reception on Endpoint 0. It is also reset b y the USB bus reset.

Bits 5:4 = STAT_RX [1:0]

Status bi ts , fo r r ecept ion

transfers.

These bits contain the informat ion abo ut the e ndpoint status, which are listed below:

STAT_RX1 STAT_RX0 Meaning

DISABLED: reception

transfers cannot be executed.

STALL: the endpoint is

stalled and all reception requests result in a STALL handshake.

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Bit 7 = Forced by hardware to 1.

Bits 6:4 = Refer to the EPnRB register for a description of these bits.

Bits 3:0 = Forced by hardware to 0.

USB INTERFACE (Cont’d)

5.6.5 Programming Considerations

The interaction between the USB interface and the application program is described below. Apart from system reset, action is always initiated by the USB interface, driven by one of the USB events associated with the Interrupt Status Register (ISTR) bits.

5.6.5.1 Initializing the Registers

At system reset, t he software must initia lize all registers to enable the USB interface to properly generate interrupts and DMA requests.

1. Initialize the DMAR, IDR, and IMR registers (choice of enabled interrupts, address of DMA buffers). Refer the paragraph titled initializing the DMA Buffers.

2. Initialize the EP0RA and EP0RB registers to enable accesses to address 0 and endp oint 0 to support USB enumeration. Refer to the paragraph titled Endpoint Initialization.

3. When addresses are received through this channel, update the content of the DADDR.

4. If needed, write the endpoint numbers in the EA fields in the EP1RB and EP2RB register.

5.6.5.2 Initializing DMA buffers

The DMA buffers are a contiguous zone of memory whose maximum size is 48 bytes. They can be placed anywhere in the memory space t o enable the reception of messages. The 10 most significant bits of the start of this memory area are specified by bits DA15-DA6 in registers DMAR and IDR, the remaining bits are 0. The memory map is shown in Figure 2.

Each buffer is filled starting from the bottom (last 3 address bits=000) up.

5.6.5.3 Endpoint Initialization

To be ready to receive: Set STAT_RX to VALID (11b) in EP0RB to enable

reception. To be ready to transmit:

1. Write the data in the DMA transmit buffer.

2. In register EPnRA, specify the num ber of bytes to be transmitted in the TBC field

3. Enable the endpoint by setting the STAT_TX bits to VALID (11b) in EPnRA.

Note: Once transmission and/or reception are enabled, registers EPnRA and/or EPnRB (respectively) must not be modified by software, as the hardware can change their value on the fly.

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When the operation is completed, they can be accessed again to enable a new operation.

5.6.5.4 Interrupt Handling Start of Frame (SOF)

The interrupt service routine may monitor the SOF events for a 1 ms synchronization event to the USB bus. This interrupt is ge nerated at the end of a resume sequence and can also be used to detect this event.

USB Reset (RESET)

When this event occurs, the DADDR register is reset, and communication is disabled i n all en dpoint registers (the USB interface will not respond to any packet). Software is responsible for reenabling endpoint 0 within 10 ms of the end of reset . To do this, set the STAT_RX bits in the EP0RB register to VALID.

Suspend (SUSP)

The CPU is warned abou t the lack of bus activity for more than 3 ms, which i s a suspend request. The software should set the USB interface to suspend mode and execute an S T 7 HA LT i ns truction to meet the USB-specified power constraints.

End Suspend (ESUSP)

The CPU is alerted by ac tivity on the US B, which causes an ESUSP interrupt. The ST7 automatically terminates HALT mode.

Correct Transfer (CTR)

1. When this event occurs, the hardware automatically sets the STAT _ TX or STAT_ RX to NAK. Note: Every valid endpoint is NAKed until software clears the CTR bit in the ISTR register, independently of the endpoint number addressed by the tr ansfer which generated t he CTR interrupt. Note: If the event triggering the CTR interrupt is a SETUP transaction, both STAT_TX and STAT_RX are set to NAK.

2. Read the PIDR to obtain the token and t he I DR to get the endpo int number related to t he last transfer. Note: When a CTR i nterrupt occurs, the TP3TP2 bits in the P IDR register and EP1-EP0 bi ts in the IDR register stay unchanged until the CTR bit in the ISTR register is cleared.

3. Clear the CTR bit in the ISTR register.

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USB INTERFACE (Cont’d)

Table 19. USB Register Map and Reset Values

Address

(Hex.)

Name

PIDR Reset Value DMAR Reset Value IDR Reset Value ISTR Reset Value IMR Reset Value CTLR Reset Value DADDR Reset Value EP0RA Reset Value EP0RB Reset Value EP1RA Reset Value EP1RB Reset Value EP2RA Reset Value EP2RB Reset Value

7 6 5 4 3210

TP3

DA15

DA7

SUSP

SUSPM0DOVRM

0 0 0 0

ST_OUT

0 1 1

ST_OUT0DTOG_TX0STAT_TX10STAT_TX00TBC3

CTRL0DTOG_RX0STAT_RX10STAT_RX00EA3

ST_OUT0DTOG_TX0STAT_TX10STAT_TX00TBC3

CTRL0DTOG_RX0STAT_RX10STAT_RX00EA3

TP2

DA14

DA6

DOVR

0 0 0

ADD6

DTOG_TX

DTOG_RX0STAT_RX10STAT_RX0

0 0

DA13

EP1

CTR

CTRM

0 0 0

ADD5

STAT_TX10STAT_TX00TBC3

DA12

EP0

ERR

ERRM

ADD4

RX_SEZ0RXD

DA11

CNT3

IOVR0ESUSP0RESET

IOVRM0ESUSPM0RESETM0SOFM

RESUME0PDWN1FSUSP1FRES

ADD3

DA10

CNT2

ADD2

TBC2

EA2

TBC2

EA2

DA9

CNT1

ADD1

TBC1

EA1

TBC1

EA1

DA8

CNT0

SOF

ADD0

TBC0

EA0

TBC0

EA0

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5.7 I²C BUS INTERFACE (I²C)

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5.7.1 Introd uction

The I²C Bus Interface serves as an in terface between the microcontroller and the serial I²C bus. It provides both multimaster and slave functions, and controls all I²C bus-specific sequencing, protocol, arbitration and timing. It supports fast I²C mode (400kHz).

5.7.2 Main Features

■ Parallel-bus/I²C protocol converter

■ Multi-master capability

■ 7-bit Addressing

■ Transmitter/Receiver flag

■ End-of-byte transmission flag

■ Transfer problem detection

I²C Master Features:

■ Clock generation

■ I²C bus busy flag

■ Arbitration Lost Flag

■ End of byte transmission flag

■ Transmitter/Receiver Flag

■ Start bit detection flag

■ Start and Stop generation

I²C Slave Features:

■ Stop bit detection

■ I²C bus busy flag

■ Detection of misplaced start or stop condition

■ Programmable I²C Address detection

■ Transfer problem detection

■ End-of-byte transmission flag

■ Transmitter/Receiver flag

5.7.3 General Description

In addition to receiving and transmitting data, this interface converts it from serial to parallel format and vice versa, using either an interrupt or polled

handshake. The interrupts are enabled or disabled by software. The interface is connected to the I²C bus by a data pin (SDAI) and by a clock pin (SCLI). It can be connected b oth with a standard I²C bus and a Fast I²C bus. This selection is made by software.

Mode Selection

The interface can operate in the four following modes:

– Slave transmitter/receiver – Master transmitter/receiver By default, it operates in slave mode. The interface automatically switches from slave to

master after it generates a START condition and from master to slave in case of arbitration loss or a STOP generation, this allows Multi-Master capability.

Communicati on Flow

In Master mode, it initiates a data transfer and generates the clock signal. A serial data tran sfer always begins with a start condition and ends with a stop condition. Both start and stop conditions are generated in master mode by software.

In Slave mode, the interface is capable of recognising its own address (7-bit), and the General Call address. The General Call address d etection may be enabled or disabled by software.

Data and addresses are transferred as 8-bit bytes, MSB first. The first byte following the start condition is the address byte; it is al ways transm itted in Master mode.

A 9th clock pulse follows the 8 clock cycles of a byte transfer, during which the receiver must send an acknowledge bit to the transmitter. Refer to Fig -

ure 1.

Figure 38. I²C BUS Protocol

SDA

SCL

START

CONDITION

MSB

ACK

12 89

STOP

CONDITION

VR02119B

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I²C BUS INTERFACE (Cont’d) The Acknowledge function may be enabled and

disabled by software. The I²C interface address and/or general call ad-

dress can be selected by software. The speed of the I²C interface may be selected be-

tween Standard (0-100 kHz) and Fast I²C (100400 kHz).

SDA/SCL Line Control

Transmitter mode: the interface holds the clock line low before transmission to wait for the microcontroller to write the byte in the Data Register.

Receiver mode: the interface holds the clock line low after reception to wait for the microcontroller to read the byte in the Data Register.

Figure 39. I²C Interface Block Diagram

The SCL frequency (F

) is controlled by a pro-

SCL

grammable clock divider which depends on the I²C bus mode.

When the I²C cell is enabled, the SDA and SCL ports must be configured as floating open-drain output or floating input . In this case, the val ue of the external pull-up resistor used depends on t he application.

When the I²C cell is disabled, the SDA and SC L ports revert to being standard I /O port pins.

DATA REG ISTER (DR)

SDA

SCL

SDAI

SCLI

DATA CON TROL

CLOCK CONTROL

CLOCK CONTROL REGISTER (CCR )

CONTRO L REGISTE R (CR)

STATUS REGISTER 1 (SR1)

STATUS REGISTER 2 (SR2)

DATA SHIFT REGISTER

COMPARATOR

OWN ADDRESS REGISTER (OAR)

CONTROL LOGIC

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INTERRUPT

I²C BUS INTERFACE (Cont’d)

5.7.4 Functional Description

Refer to the CR, SR1 and SR2 registers in Section

0.1.7. for the bit definitions.

By default the I²C interface operates in Slave mode (M/SL bit is cleared) except when it initiates a transmit or receive sequence.

5.7.4.1 Slave Mode

As soon as a start condition is detected, the address is received from the S DA line and s ent to the shift register; then it is compared with the address of the interface or the General Call address (if selected by software).

Address not matched: the interface ignores it and waits for another Start condition.

Address matched: the interface generates in sequence:

– An A ckno wledge pul se is generated if the ACK

bit is set.

– EVF and ADSL bits are set with an interrupt i f the

ITE bit is set.

Then the interface waits for a read of the SR1 register, holding the SCL line low (see Figure 3 Transfer sequencing EV1). Next, software must read the DR register to determine from the least significant bit if the slave must enter Receiver or Transmitter mode.

Slave Receiver

Following the address reception and after SR1 register has been read, the slave receives bytes from the SDA line into the DR register via the internal shift register. After each byte the interface generates in sequence:

– An A ckno wledge pul se is generated if the ACK

bit is set

– EVF and BTF bits are set with an interrupt if the

ITE bit is set.

Then the interface waits for a read of the SR1 register followed by a read of the DR register, holding the SC L li ne low (see Figure 3 Transfer sequenc- ing EV2).

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The slave waits for a read of the SR1 register followed by a write in the DR register, holding the SCL line low (see Figure 3 Transfer sequencing EV3).

When the acknowledge pulse is received: – The EVF and BTF bits are set by hardware with

an interrupt if the ITE bit is set.

Closing Slave Communication

After the last data byte is trans ferred a Sto p Condition is generated by the master. The interface detects this condition and sets:

– EVF and STOPF bits with an interrupt if the ITE

bit is set.

Then the interface waits for a read of the SR2 register (see Figure 3 Transfer sequencing EV4).

Error Cases

– BERR: Detection of a Stop or a Start condition

during a byte transfer. In this case, the EVF and BERR bits are set with an interrupt if the ITE bit is set. If it is a Stop condition, then the interface discards the data, released the lines and waits for another Start condition. If it is a Start condition, then the interface discards the data and waits for the next slave address on the bus.

– AF: Detection of a non-acknowledge bit. In this

case, the EVF and AF bits are set with an interrupt if the ITE bit is set.

Note: In both cases, the SCL line is not held low; however, the SDA line can remain low due to possible “0” bits transmitted last. It is then necessary to release both lines by software.

How to Release the SDA / SCL lines

Set and subsequently clear the STOP bit while BTF is set. The SDA/SC L lines are release d after the transfer of the current byte.

Slave Transmitter

Following the address reception and after the SR1 register has been read, the slave sends bytes from the DR regi ster to the SDA li ne via the internal shift register.

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I²C BUS INTERFACE (Cont’d)

5.7.4.2 Master Mode

To switch from default Slave mode to Master mode, a Start condition generation is needed.

Start Condition and Transmit Slave Address

Setting the START bit while the BUSY bit is cleared causes the interface to switch to Master mode (M/SL bit set) and generates a Start condition.

Once the Start condition is sent: – The EVF and SB bits are set by hardware with

an interrupt if the ITE bit is set.

Then the master waits for a read of the SR1 register followed by a write in the DR register with the Slave address byte, holding the SCL line low (see Figure 3 Transfer sequencing EV5).

Then the slave address byte is sent to the S DA line via the internal shift register.

After completion of this transfer (and acknowledge from the slave if the ACK bit is set):

– The EVF bit is set by hardware with interrupt

generation if the ITE bit is set.

Then the master waits for a read of the SR1 register followed by a write in t he CR register (f or example set PE bit), holding the SCL line low (see Fig-

ure 3 Transfer sequencing EV6).

Next the master must enter Rec eiver or Transm itter mode.

Master Receiver Following the address transmission and after the

SR1 and CR registers have be en accessed, the master receives bytes from the S DA line into the DR register via the internal shift register. After each byte the interface generates in sequence:

– An Acknowledge pulse is generated if if the ACK

bit is set

– EVF and BTF bits are set by hardware with an in-

terrupt if the ITE bit is set.

Then the interface waits for a read of the SR1 register followed by a read of the DR register, holding the SC L li ne low (see Figure 3 Transfer sequenc- ing EV7).

To close the communication: before reading the last byte from the DR register, set the STOP bit to generate the Stop condition . The interfa ce returns automatically to slave mode (M/SL bit cleared).

Note: In order to generate the non-acknowledge pulse after the last received data byte, the ACK bit must be cleared just before reading the second last data byte.

Master Transmitter

Following the address transmission and after SR1 register has been read, the master sends bytes from the DR register to the SDA line via the internal shift register.

The master waits for a read of the SR1 register followed by a write in the DR register, holding the SCL line low (see Figure 3 Transfer sequencing EV8).

When the acknowledge bit is received, the interface sets:

– EVF and BTF bits with an interrupt if the ITE bit

is set.

To close the communication: after writing the last byte to the DR register, set the STOP bit to generate the Stop c ondition. The interfac e goes automatically back to slave mode (M/SL bit cleared).

Error Cases

– BERR: Detection of a Stop or a Start condition

during a byte transfer. In this case, the EVF and BERR bits are set by hardware with an interrupt if the ITE bit is set.

– AF: Detection of a non-acknowledge bit. In this

case, the EVF and AF bits are set by hardware with a n in terru p t i f th e ITE bi t i s se t. To resume , set the START or STOP bit.

– ARLO: Detection of an arbitration lost condition.

In this case the ARLO bit is set by hardware (with an interrupt if the ITE bit is set and the interface goes automatically back to slave mode (the M/SL bit is cleared).

Note: In all these cases, the SCL line is not held low; however, the SDA line can remain low due to possible “0” bits transmitted last. It is then necessary to release both lines by software.

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I²C BUS INTERFACE (Cont’d)

Figure 40. Transfer Sequencing

ave Receiver

S Address A Data1 A Data2 A

EV1 EV2 EV2 EV2 EV4

DataN A P

.....

Slave Transmitter

S Address A Data1 A Data2 A

EV1 EV3 EV3 EV3 EV3-1 EV4

DataN NA P

.....

Master Receiver

S Address A Data1 A Data2 A

EV5 EV6 EV7 EV7 EV7

DataN NA P

.....

Master Trans mitter

S Address A Data1 A Data2 A

EV5 EV6 EV8 EV8 EV8 EV8

DataN A P

.....

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Legend:

S=Start, P=Stop, A=Acknowledge, NA=Non-acknowledge EVx=Event (with interrupt if ITE=1)

EV1: EVF=1, ADSL=1, cleared by reading the SR1 register. EV2: EVF=1, BTF=1, cleared by reading the SR1 register followed by reading the DR register. EV3: EVF=1, BTF=1, cleared by reading the SR1 register followed by writing the DR register.

EV3-1: EVF=1, AF=1, BTF=1; AF is cleared by reading the SR1 register. The BTF is cleared

by releasing the lines (STOP=1, STOP=0) or by writing the DR register (DR=FFh).

Note: If lines are released by STOP=1, STOP=0, the subsequent EV4 is not seen. EV4: EVF=1, STOPF=1, cleared by reading the SR2 register. EV5: EVF=1, SB=1, cleared by reading the SR1 register followed by writing the DR register. EV6: EVF=1, cleared by reading the SR1 register followed by writing the CR register

(for example PE=1).

EV7: EVF=1, BTF=1, cleared by reading the SR1 register followed by reading the DR register. EV8: EVF=1, BTF=1, cleared by reading the SR1 register followed by writing the DR register.

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I²C BUS INTERFACE (Cont’d)

5.7.5 Low Power Modes Mode Description

WAIT

HALT

5.7.6 Interrupts

Figure 41. Event Flags and Interrupt Generation

No effect on I²C interface. I²C interrupts exit from Wait mode.

I²C registers are frozen.

In Halt mode, the I ²C in terface is inact ive and does not ack nowled ge da ta on the bus. The I²C interface resumes operation when the MCU is woken up by an interrupt with “exit from Halt mode” capability.

BTF

ADSL

STOPF

ARLO BERR

ITE

INTERRUPT

EVF

EVF can also be set by EV6 or an error from the SR2 register.

Interrupt Event

End of Byte Transfer Event BTF Address Matched Event (Slave mode) ADSEL Yes No Start Bit Generation Event (Master mode) SB Yes No Acknowledge Failure Event AF Yes No Stop Detection Event (Slave mode) STOPF Yes No Arbitration Lost Event (Multimaster configuration) ARLO Yes No Bus Error Event BERR Yes No

The I²C interrupt events are connected to the same interrupt vector (see Interrupts chapter).

They generate an interrupt if the corresponding Enable Control Bit is set and the I-bit in the CC

Event

Flag

Enable

Control

Bit

ITE

Exit

from

Wait

Yes No

Exit

from

Halt

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I²C BUS INTERFACE (Cont’d)

5.7.7 Register Description

I²C CONTROL REGISTER (CR)

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

Bit 2 = ACK This bit is set and cleared by software. It is also cleared by hardware when the interface is disabled (PE=0). 0: No acknowledge returned

Acknowledge enable.

1: Acknowledge returned after an address byte or

0 0 PE ENGC START ACK STOP ITE

a data byte is received

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Bits 7:6 = Reserved. Forced to 0 by hardware. Bit 5 = PE

Peripheral enable.

This bit is set and cleared by software. 0: Peripheral disabled 1: Master/Slave capability Notes:

– W hen PE= 0, all the bits of the CR register and

the SR register except the Stop bit are reset. All outputs are released while PE=0

– W hen PE= 1, the correspond ing I/O pins are se-

lected by hardware as alternate functions.

– To enable the I²C interface, write the CR register

TWICE with PE=1 as the first write only activates the interface (only PE is set).

Bit 4 = ENGC

Enable General Call.

This bit is set and cleared by software. It is also cleared by hardware when the interface is disabled (PE=0). The 00h General Call address is acknowledged (01h ignored). 0: General Call disabled 1: General Call enabled

Bit 3 = START

Generation of a Start condition

This bit is set and cleared by software. It is also cleared by hardware when the interface is disabled (PE=0) or when the Start condition is sent (with interrupt generation if ITE=1).

– In master mode :

0: No start generation 1: Repeated start generation

– In slave mode :

0: No start generation 1: Start generation when the bus is free

Bit 1 = STOP

Generation of a Stop condition

This bit is set and cleared by software. It is also cleared by hardware in master mode. Note: This bit is not cleared when the interface is disabled (PE=0).

– In Master mode:

0: No stop generation 1: Stop generation after the current byte transfer or after the current Start condition is sent. The STOP bit is cleared by hardware when the Stop condition is sent.

– In Slave mode:

0: No stop generation 1: Release the SCL and SDA lines after the current byte transfer (BTF=1). In this mode the STOP bit has to be cleared by software.

Bit 0 = ITE

Interrupt enable.

This bit is set and cleared by software and cleared by hardware when the interface is disabled (PE=0). 0: Interrupts disabled 1: Interrupts enabled

Refer to Figure 4 for the relationship between the events and the interrupt.

SCL is held low when the SB, BTF or ADS L flags or an EV6 event (See Figure 3) is detected.

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ST7263

I²C BUS INTERFACE (Cont’d) I²C STATUS REGISTER 1 (SR1)

Read Only Reset Value: 0000 0000 (00h)

EVF 0 TRA BUSY BTF ADSL M/SL SB

Bit 3 = BTF This bit is set by hardware as soon as a byte is correctly received or transmitted with interrupt generation if ITE=1. It is cleared by software reading SR1 register followed by a read or write of DR register. It is also cleared by hardware when the interface is disabled (PE=0).

– Following a byte transmission, this bit is set after

Bit 7 = EVF

Event flag.

This bit is set by hardware as soon as an event occurs. It is cleared by software reading SR2 register in case of error event or as described in Figure 3. It is also cleared by hardware when the interface is disabled (PE=0). 0: No event 1: One of the following events has occurred:

– BTF=1 (Byte received or transmitted) – ADSL=1 (Address matched in Slave mode

while ACK=1 )

– SB=1 (Start condition generated in Master

reception of the acknowledge clock pulse. In case an address byte is sent, this bit is set only after the EV6 event (See Figure 3). BTF is cleared by reading SR1 register followed by writing the next byte in DR register.

– Following a byte reception, this bit is set after

transmission of the acknowledge clock pulse if ACK=1. BTF is cleared by reading SR1 register

followed by reading the byte from DR register. The SCL line is held low while BTF=1. 0: Byte transfer not done

1: Byte transfer succeeded

mode)

– AF=1 (No acknowledge received after byte

transmission)

– STOPF=1 (Stop condition detected in Slave

mode) – ARLO=1 (Arbitration lost in Master mode) – BERR=1 (Bus error, misplaced Start or Stop

condition detected) – Address byte successfully transmitted in Mas-

ter mode.

Bit 2 = ADSL This bit is set by hardware as soon as the received slave address matched with the OAR register content or a general call is recognized. A n in terrupt is generated if ITE=1. It is c leared by sof tware reading SR1 register or by hardware when t he interface is disabled (PE=0).

The SCL line is held low while ADSL=1. 0: Address mismatched or not received

1: Received address matched

Byte transfer finished.

Address matched (Slave mode).

Bit 6 = Reserved. Forced to 0 by hardware.

Bit 5 = TRA

Transmitter/Receiver.

When BTF is set, TRA=1 if a dat a byte has been transmitted. It is cleared automatically when BTF is cleared. It is also cleared by hardware after detection of Stop condition (STOPF=1), loss of bus arbitration (ARLO=1) or when the interface is disabled (PE=0). 0: Data byte received (if BTF=1) 1: Data byte transmitted

Bit 4 = BUSY

Bus busy

. This bit is set by hardware on de tection of a S tart condition and cleared by hardware on detection of a Stop condition. I t indicates a communi cation in progress on the bus. This information is still updated when the interface is disabled (PE=0). 0: No communication on the bus 1: Communication ongoing on the bus

80/109

Bit 1 = M/SL

Master/Slave.

This bit is set by hardware as soon as the interface is in Master mode (writing START=1). It is cleared by hardware after detecting a Stop condition on the bus or a loss of arbitration (ARLO=1). It is also cleared when the interface is disabled (PE=0). 0: Slave mode 1: Master mode

Bit 0 = SB

Start bit (Master mode).

This bit is set by hardware as soon as the Start condition is generated (following a write START=1). An interrupt is generated if ITE=1. It is cleared by software reading SR1 register followed by writing the address byte in DR register. It is al so cleared by hardware when the interface is disabled (PE=0). 0: No Start condition 1: Start condition generated

I²C BUS INTERFACE (Cont’d) I²C STATUS REGISTER 2 (SR2)

Read Only Reset Value: 0000 0000 (00h)

es the arbitration of the bus to another master. An interrupt is generated if ITE=1. It is cleared by software reading SR2 register or by hardware when the interface is disabled (PE=0).

After an ARLO event the interface switches back

0 0 0 AF STOPF ARLO BERR GCAL

automatically to Slave mode (M/SL=0). The SCL line is not held low while ARLO=1. 0: No arbitration lost detected

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

1: Arbitration lost detected

ST7263

Bit 4 = AF

Acknowledge failure

. This bit is set by hardware when no acknowledg e is returned. An interrupt is generated if ITE=1. It is cleared by software reading SR2 register or by hardware when the interface is disabled (PE=0).

The SCL line is not held low while AF=1. 0: No acknowledge failure

1: Acknowledge failure

Bit 3 = STOPF

Stop detection (Slave mode).

This bit is set by hardware when a St op condition is detected on the bus after an acknowledge (if ACK=1). An interrupt is generated if ITE=1. It is cleared by software reading SR2 register or by hardware when the interface is disabled (PE=0).

The SCL line is not held low while STOPF=1. 0: No Stop condition detected

1: Stop condition detected

Bit 2 = ARLO

Arbitration lost

This bit is set by hardware when the interface los-

Bit 1 = BERR

Bus error.

This bit is set by hardware when the interface detects a misplaced Start or Stop condition. An interrupt is generated if ITE=1. It is cleared by software reading SR2 register or by hardware when the interface is disabled (PE=0).

The SCL line is not held low while BERR=1. 0: No misplaced Start or Stop condition

1: Misplaced Start or Stop condition

Bit 0 = GCAL

General Call (Slave mode).

This bit is set by hardware when a general call address is detected on the bu s while ENGC= 1. It is cleared by hardware detecting a Stop condition (STOPF=1) or when the interface is disabled (PE=0).

0: No general call address detected on bus 1: general call address detected on bus

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ST7263

I²C BUS INTERFACE (Cont’d) I²C CLOCK CONTROL REGISTER (CCR)

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

I²C OWN ADDRESS REGISTER (OAR)

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

FM/SM CC6 CC5 CC4 CC3 CC2 CC1 CC0

Bit 7 = FM/SM

Fast/Standard I²C mode.

This bit is set and cleared by software. It is not cleared when the interface is disabled (PE=0).

0: Standard I²C mode 1: Fast I²C mode

Bits 6:0 = CC6-CC0 These bits select the s peed of t he bus (F

7-bit clock divider.

) de-

SCL

pending on the I²C mode. They are not cleared when the interface is disabled (PE=0).

– St andard m ode (FM /SM=0): F

= f

SCL

– Fas t mode (FM /SM =1): F

= f

SCL

Note: The programmed F

/(2x([CC6..CC0]+ 2))

CPU

SCL

/(3x([CC6..CC0]+ 2))

CPU

SCL

<= 100kHz

SCL

> 100kHz

assumes no load on

ADD7 ADD6 ADD5 ADD4 ADD3 ADD2 ADD1 ADD0

Bits 7:1 = ADD7-ADD1

Interface address

These bits define the I²C bus add ress o f the in terface. They a re not cleared when the interface is disabled (PE=0).

Bit 0 = ADD0

Address direction bit.

This bit is don’t care, the interface ack nowledges either 0 or 1. It is not cleared when the interface is disabled (PE=0).

Note: Address 01h is always ignored.

SCL and SDA lines.

I²C DATA REGISTER (DR) Read / Write

Reset Value: 0000 0000 (00h)

D7 D6 D5 D4 D3 D2 D1 D0

Bits 7:0 = D7-D0

8-bit Data Register.

These bits contains the byte to be received or transmitted on the bus.

– Tr ansmi tter mode: Byte transmiss ion start auto-

matically when the software writes in the DR register.

– Receiver mode: the first data byte is received au-

tomatically in the DR register using the least significant bit of the address. Then, the next data bytes are received one by one after reading the DR register.

82/109

Table 20. I2C Register Map

Address

(Hex.)

39 DR DR7 .. DR0 3B OAR ADD7 .. ADD0 3C CCR FM/SM CC6 .. CC0 3D SR2 AF STOPF ARLO BERR GCAL 3E SR1 EVF TRA BUSY BTF ADSL M/SL SB 3F CR PE ENGC START ACK STOP ITE

Name

76543210

ST7263

83/109

ST7263

5.8 8-BIT A/D CONVERTER (ADC)

5.8.1 Introd uction

The on-chip Analog to Digital Converter ( ADC) peripheral is a 8-bit, successive approximation converter with internal sample and hold circuitry. This peripheral has up to 8 multiplexed analog input channels (refer to device pin out description) that allow the peripheral to convert the analog vol tage levels from up to 8 different sources.

The result of the conversion is stored in a 8-bit Data Register. The A/D converter is controlled through a Control/Status Register.

Figure 42. ADC Block Diagram

AIN0 AIN1

AIN2 AIN3 AIN4 AIN5 AIN6 AIN7

ANALOG

MUX

SAMPLE

HOLD

5.8.2 Main Features

■ 8-bit conversion

■ Up to 8 channels with multiplexed input

■ Linear successive approximation

■ Data register (DR) which contains the results

■ Conversion complete status flag

■ On/Off bit (to reduce consumption)

The block diagram is shown in Figure 42.

COCO

0CH0CH1CH2--ADON

(Control Status Register) CSR

ANALOG TO DIGITAL CONVERTER

84/109

CPU

AD7

AD4 AD0AD1AD2AD3AD6 AD5

(Data Register) DR

8-BIT A/D CONVERTER (ADC) (Cont’d)

5.8.3 Functional Description

The high level reference voltage V connected externally to the V reference voltage V nally to the V

pin. In some devices (refer to de-

must be connected exter-

SSA

pin. The low level

must be

DDA

vice pin out description) high and low level reference voltages are internally c onnected to the V and VSS pins.

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

Figure 43. Recommended Ext. Connections

0.1µF

V V

DDA

SSA

ST7

AIN

Px.x/AINx

Characteristics:

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

If input voltage is greater than or equal to V

(voltage reference high) then results = FFh (full scale) without overflow indication.

If input voltage ≤ V

(vol tage refe renc e l ow) then

the results = 00h. The conversion time is 64 CPU clock cycles in-

cluding a sampling time of 31.5 CPU clock cycles.

is the maximum recommended impedance

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.

The A/D converter is linear and the digital result of the conversion is given by the formula:

ST7263

The accuracy of the conversion is described in the Electrical Characteristics Section.

Procedure:

Refer to the CSR and DR register description section for the bit definitions.

Each analog input pin must be configured as input, no pull-up, no interrupt. Refer to the “I/O Ports” chapter. Using these p ins as analog inputs does not affect the ability of the port to be r ead as a logic input.

In the CSR register:

– Select the CH2 to CH0 bits to assign the ana-

log channel to convert. Refer to Table 21

Channel Selection.

– Set the ADON bi t. Then the A /D converter is

enabled after a stabilization time (typically 30 µs). It then performs a c ontinuou s conv ersion of the selected channel.

When a conversion is complete

– The COCO bit is set by hardware. – No interrupt is generated. – The result is in the DR register.

A write to the CSR register aborts the current conversion, resets the COCO bit and starts a new conversion.

5.8.4 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.

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 stabilisation time before accurate conversions can be performed.

Digital res ult =

255 x Input Voltage Reference Voltage

Where Reference Voltage is V

5.8.5 Interrupts

None.

- VSS.

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ST7263

8-BIT A/D CONVERTER (ADC) (Cont’d)

5.8.6 Register Description CONTROL/STATUS REGISTER (CSR)

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

COCO - ADON 0 - CH2 CH1 CH0

Bit 7 = COCO

Conversion Complete

This bit is set by hardware. It is cleared by software reading the result in the DR register or writing to the CSR register. 0: Conversion is not complete. 1: Conversion can be read from the DR register.

Table 21. Channel Selection

Pin* CH2 CH1 CH0

AIN0 000 AIN1 001 AIN2 010 AIN3 011 AIN4 100 AIN5 101 AIN6 110 AIN7 111

*IMPORTANT NOTE:

The number of pins AND the channel selection vary according to the device. REFER TO THE DEVICE PINOUT).

Bit 6 = R eserved . Must always be cleared.

Bit 5 = ADON

A/D converter On

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

Note: A typical 30 µs delay time is necessary for the ADC to stabilize when the ADO N b it is set.

Bit 4 = R eserved . Forced by hardware to 0.

Bit 3 = R eserved . Must always be cleared.

Bits 2:0: CH[2:0]

Channel Selection

These bits are set and cleared by software. They select the analog input to convert.

DATA REGISTER (DR)

Read Only Reset Value: 0000 0000 (00h)

AD7AD6AD5AD4AD3AD2AD1AD0

Bit 7:0 = AD[7:0]

Analog Converted Value

This register contains the converted analog value in the range 00h to FFh.

Reading this register resets the COCO flag.

86/109

6 INSTRUCTION SET

ST7263

6.1 ST7 ADDRESSING MODES

The ST7 Core features 17 different addressing modes which can be classified in 7 main groups:

Addressing Mode Example

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

so, most of the ad dressing modes may be subdivided in two sub-modes 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.

The ST7 Instruction set is designed to minimize the number of bytes required per instruction: To do

Table 22. 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 D irect jrne loop PC-128/PC+1 27 Relative I ndire ct jrne [$10] PC -128 /PC+1 27 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

Destination/

Source

Pointer

Address

(Hex.)

00..FF byte + 2

Pointer

Size

(Hex.)

Length

(Bytes)

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

+ 1

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

87/109

ST7263

ST7 ADDRESSING MODES (Cont’d)

6.1.1 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 Sub-routine Return

IRET Interrupt Sub-routine 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 Multip licatio n SLL, SRL, SRA, RLC,

RRC SWAP Swap Nibbles

6.1.2 Immediate

Immediate instructions have two 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

Wait For Interrupt (Low Power Mode)

Halt Oscillator (Lowest Power Mode)

Shift and Rotate Operations

6.1.3 Direct

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

The direct addressing m ode consists of two submodes:

Direct (short)

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

Direct (lon g)

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

6.1.4 Indexed (No Offset, Short, Long)

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

The indirect addressing mode consists of three sub-modes:

Indexed (No Offset)

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

Indexed (Short)

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

Indexed (long)

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

6.1.5 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 th e op co de. Th e i ndirect addressing mode consists of two sub-modes:

Indirect (short)

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

Indirect (lon g)

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.

88/109

ST7 ADDRESSING MODES (Cont’d)

6.1.6 Indi re ct In dexed (Shor t, Long)

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

The indirect indexed addressing mode consists of two sub-modes:

Indirect Indexed (Short)

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

Indirect Inde xed (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 23. Instructions Supporting Direct, Indexed, Indirect and Indirect Indexed Addressing Modes

ST7263

SWAP Swap Nibbles CALL, JP Call or Jump subroutine

6.1.7 Relative Mode (Direct, Indirect)

This addressing mode is used to m odify 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 t he 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

Arithmetic Addition/subtraction operations

Bit Test and Jump Operations

Shift and Rotate Operations

Function

89/109

ST7263

6.2 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 Code Condition Flag modification SIM RIM SCF RCF

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

Using a pre-b y te

The instructions are described with one to four bytes.

In order to extend the number of available opcodes for an 8-bit CPU (256 opcodes), three different prebyte opcodes a re 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 A dditional word (0 to 2) according to the

number of bytes required to compute the effective address

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 addres sing mode . The prebytes are:

PDY 90 Replace an X based instruction using

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

PIX 92 Replace an instruction using direct, 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 Repla ce an instruction using X indirect

indexed addressing mode by a Y one.

90/109

ST7263

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 Abs olute 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 >

91/109

ST7263

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

92/109

7 ELECTRIC AL CHARACTERI STICS

7.1 ABSOLUTE MAXIMUM RATINGS

ST7263

Devices of the ST72 family contain circuitry to protect the inputs against damage due to high static voltage or electric fields. Nevertheless, it is recommended that normal precautions be observed in order to avoid subjecting this high-impedance circuit to voltages above t hose quoted in the Abs olute Maximum Ratings. For proper operation, it is recommended that the input voltage V

be con-

strained within the range:

- 0.3V) ≤ VIN ≤ (V

+ 0.3V)

connect them to an appropriate logi c voltage level such as V connect (same remark for

or VDD. it is also recommended to

DDA

and V

together on application.

and VSS).

SSA

All the voltage in the following tables are referenced to V

Stresses above those listed as “Absolute Maximum Ratings” may c ause permanent damage to the device. Functional operation of the device at these conditions is no t impl ied. E xposure t o m ax imum rating condit ions for extended periods m ay

To enhance reliability of operation, it is recom-

affect device reliab i lity.

mended to configure unused I/Os as inputs and to

Table 24.

Absolute Maximum Ratings (Voltage Referenced to V

Symbol Ratin gs Value Un it

DDA

- VDD| Max. variations on Power Line 50 mV

DDA

- VSS| Max. variations on Ground Line 50 mV

SSA

- I

VDD

VSS

OUT

STG

PD Power Dissipation 350 mW

ESD ESD susceptibility 2000 V

Recommended Supply Voltage - 0.3 to +6.0 V Analog Reference Voltage - 0.3 to +6.0 V

Total current into VDD/V Input Voltage VSS - 0.3 to VDD + 0.3 V Output Voltage VSS - 0.3 to VDD + 0.3 V

Ambient Temperature Range

Storage Temperature Range -65 to +150 °C Junction Temperature 150 °C

)

80/80 mA

to T

0 to + 70

°C

93/109

ST7263

7.2 THERMAL CHARACTERISTICS

The average chip-junction temperature, T grees Celsius, may be calculated using the follow-

, in de-

An approximate relationship between P (if P

is neglected) is given by:

I/O

ing equation:

= K÷ (TJ + 273°C) (2)

= TA + (PD x θJA) (1)*

Therefore:

Where:

– T

is the Ambient Temperature in °C,

– θJ

is the Package Junction-to-Ambient Thermal

Resistance, in °C/W,

is the sum of P

– P

is the product of I

– P

INT

and P

INT

DD and VDD

I/O

, expressed in

Watts. This is the Chip Internal Power

represents the Power Dissipation on Input

– P

I/O

and Output Pins; User Determined.

For most applications P glected. P

may be significant if the device is con-

I/O

I/O<PINT

and may be ne-

K = P

x (TA + 273°C) + θJA x P

Where:

– K is a constant for the particular part, which may

be determined from equation (3) by measuring P

(at equilibrium) for a known TA. Using this val-

ue of K, the values of P

and TJ may be obtained

by solving equations (1) and (2) iteratively for any value of T

figured to drive Darlington bases or sink LED Loads.

Table 25. Thermal Characteristics

Symbol Package Typical Value Unit

SO34 70

PSDIP32 50

°C/W

and T

(3)

(*): Maximum chip dissipation can directly be obtained from T

(max), θJA and TA parameters.

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7.3 OPERATING CONDITIONS General Operating Conditions

= 0 to +70°C unless otherwise specified)

Symbol Parameter Conditions Min Max Unit

= 4 MHz ; USB not guaranteed 3.00 4.00 V

CPU

= 8 MHz ; USB not guaranteed V

OSC

CPU

Supply voltage

= 8 MHz or 4 MHz

CPU

USB guaranteed f

= 8 MHz or 4 MHz

CPU

USB not guaranteed

External clock frequency 12 24 MHz

IT+

4.0 5.25

5.25 5.50

Note 1: USB 1.1 specifies that the power supply must be between 4.0 0 and 5.25 Volts. The USB cell is therefore guaranteed only in that range.

4.00

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7.4 POWER CONSUMPTION

= 0 to +70°C unless otherwise specified)

GENERAL

Symbol Parameter Conditions Min Typ. Max Unit

RUN & WAIT mode

Operating Supply Voltage

Analog Reference Voltage 4 5 5.5 V

DDA

CPU RUN mode (see Note 1)

CPU WAIT mode (See Note 2) 8 12 mA

CPU HALT mode (see Note 3) 100

USB Suspend mode (see Note 4) 350 450

Note 1: All peripherals running. Note 2: Oscillator, 16-bit Timer (free running counter) and watchdog running.

All others peripherals (including EPROM/RAM memories) disabled.

Note 3: CPU in HALT mode, USB Transceiver disabled, Low Voltage Reset function enabled. Note 4: Low voltage reset function enabled.

CPU in HALT mode. USB in suspend mode. External pull-up (1.5Kohms to USBVCC) and pull-down (15Kohms to V connected on drivers.

Note 5: V

= 5.5 V except in USB Suspend mode where VDD = 5.25 V

= 24 MHz

OSC

= 8 MHz

CPU

I/O in input mode

= 8 MHz,

CPU

= 20°C

(For V

: see Note 5)

4 5 5.5 V

14 20 mA

SSA

)

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7.5 I/O PORT CHARACTERISTICS

= 0 to +70°C unless otherwise specified)

STANDARD I/O PORT PINS

Symbol Parameter Conditions Min Typ M ax Unit

Output Low Level Voltage Port A1,

Port A2 (High Current open drain)

Output Low Level Voltage Port A0,

Port A(3:7), Port C(0:2), Push Pull

Output Low Level Voltage Port B (0:7),

Push Pull

CIO I/O Pin Capacitance

f(IO)out

r(IO)out

Output High Level Voltage Port A0,

Port A(3:7), Port C(0:2) Push Pull

Output High Level Voltage Port B (0:7)

Push Pull

Input High Level Voltage

PA(0:7),PB(0:7),PC(0:2),RESET

Input Low Voltage PA(0-7),

PB(0-7), PC(0-2), RESET

Pull-up resistor VDD = 5V 80 100 120 k

Output High to Low Level Fall Time

All I/O ports

Output Low to High Level Rise Time

I/O ports in Push Pull mode

External Interrupt pulse time

All voltages are referred to VSS unless otherwise specified.

Note 1: Guaranteed by design, not tested in production. Note 2: Data based on characterization results, not tested in production.

= -25mA VDD=5V - - 1.5 V

= -1.6mA VDD=5V - - 0.4 V

= -10mA VDD=5V - - 1.3 V

= 1.6mA VDD-0.8 - - V

= 10mA VDD-1.3 - - V

Leading Edge 0.7xV

Trailing Edge V

0.3xV

5pF

CL=50pF

Between 10% and 90%

Ω

CPU

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7.6 LOW VOLTAGE DETECTOR (LVD) CHARACTERISTICS

LOW VOLTAGE RESET Electrical Specifications

Symbol Parameter Conditions Min Typ Max Unit

IT+

IT-

hys

Low Voltage Reset Threshold

rising

Low Voltage Reset Threshold

falling

Hysteresis (V

IT+

- V

) 200 250 mV

IT-

7.7 CONTROL TIMING CHARACTERISTICS

Max. Variation

50mV/µs

Max. Variation

50mV/µs

3.6 3.75 4.0 V

3.2 3.5 3.7 V

(Operating conditions T

= 0 to +70°C unless otherwise specified)

CONTROL TIMINGS

Symbol Parameter Conditions

OSC

CPU

PORL

DOGL

DOG

OXOV

DDR

Note 1: The minimum period t

Oscillator Frequency 24 MHz Operating Frequency 8 MHz External RESET

Input pulse Width Internal Power Reset Duration 4096 t Watchdog & Low Voltage Reset

Output Pulse Width Watchdog Time-out

= 8MHz

cpu

Crystal Oscillator Start-up Time

Power up rise time from VDD = 0 to 4V 100 ms

should not be less than the number of cycle times it takes to execute the

ILIL

interrupt service routine plus 21 cycles.

Value

Min Typ. Max

1.5 t

200 ns

49152

3145728

384

50 ms

Unit

CPU

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7.8 COMMUNICATION INTERFACE CHARACTERISTICS

The values given in the specifications of dedicated functions are generally not applicable for chips. Therefore, only the limits listed below are val id f or

the product. T = 0... +70°C, V otherwise specified

- VSS = 5 V unless

7.8.1 USB - Universal Bus Interface

(Operating conditions T

USB DC Electrical Characteristics

Parameter Symbol Conditions Min. Max. Unit

Input Levels:

Differential Input Sensitivity VDI I(D+, D-) 0.2 V Differential Common Mode Range VCM Includes VDI range 0.8 2.5 V Single Ended Receiver Threshold VSE 0.8 2.0 V

Output Levels

Static Output Low VOL RL of 1.5K ohms to 3.6v 0.3 V

Static Output High VOH RL of 15K ohm to V

USBVCC: voltage level USBV V

= 0 to +70°C, VDD = 4.0 to 5.25V unless otherwise specified)

=5v 3.00 3.60 V

2.8 3.6 V

Note 1: RL is the load connected on the USB drivers. Note 2: All the voltages are measured from the local ground potential.

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COMMUNICATION INTERFACE CHARACTERISTICS (Cont’d) Figure 44. USB: Data signal Rise and fall time

Differential

Data Li nes

VCRS

Crossover

points

USB: Low speed electrical characteristics

Parameter Symbol Conditions Min Max Unit

Driver characteristics:

Rise time tr Note 1,CL=50 pF 75 ns

Fall Time tf Note 1, CL=50 pF 75 ns

Rise/ Fall Time matching trfm tr/tf 80 120 %

Output signal Crossover

Voltage

Note1: Measured from 10% to 90% of the data signal. For more detailed informations, please refer to Chapter 7 (Electrical) of the USB specification (version 1.1).

VCRS 1.3 2.0 V

Note 1, CL=600 pF 300 ns

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ST ST7263 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual