STMICROELECTRONICS ST72T631K4B1

ST7263
LOW SPEED USB 8-BIT MCU FAMILY with up to 16K MEMORY,
up to 512 BYTES RAM, 8-BIT ADC, WDG, TIMER, SCI & I2C
DATASHEET
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Up to 16Kbytes program memory
Data RAM: up to 512 bytes with 64 bytes stack
Run, Wait and Halt CPU modes
12 or 24 MHz oscillator
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)
I2C Multi Master Interface up to 400 KHz
(16K program memory version only)
PSDIP32
CSDIP32W
SO34 (Shrink)
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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 (under Windows)
including assembler, linker, C-compiler,
archiver, source level debugger, software
library, hardware emulator, programming
boards and gang programmers
Table 1. Device Summary
Features
ROM - OTP (bytes)
RAM (stack) - bytes
Peripherals
ST72631
512 (64)
Watchdog, 16-bit timer,
SCI, ADC, USB
Watchdog, 16-bit timer,
ADC, USB
4.0V to 5.5V
8 Mhz (with 24 MHz oscillator) or 4 MHz (with 12 MHz oscillator)
Operating temperature
Packages
EPROM device
Note 1: EPROM version for development only
August 2000
ST72633
4K
256 (64)
Watchdog, 16-bit timer, SCI, I2C, ADC,
USB
Operating Supply
CPU frequency
ST72632
8K
16K
0°C to +70°C
SO34/SDIP32
ST72E631 1 (CSDIP32W)
Rev. 1.8
1/109
1
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) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.2.2 Watchdog Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.2.3 External Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4 INTERRUPTS AND POWER SAVING MODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.1 INTERRUPTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
18
18
18
20
20
4.1.1 Interrupt Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2
4.2 POWER SAVING MODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
4.2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2.2 HALT mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2.3 WAIT mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5 ON-CHIP PERIPHERALS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.1 I/O PORTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
23
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24
25
25
5.1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.1.2 Functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.1.3 I/O Port Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.1.4 Port A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.1.5 Port B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.1.6 Port C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.1.7 Register Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.2 MISCELLANEOUS REGISTER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
25
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26
27
29
30
31
32
5.3 WATCHDOG TIMER (WDG) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
5.3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.3.2 Main Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.3.3 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.3.4 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.3.5 Register Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.4 16-BIT TIMER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
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33
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36
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5.4.2 Main Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
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5.4.3 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.4.4 Low Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.4.5 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.4.6 Summary of Timer modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.4.7 Register Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.5 SERIAL COMMUNICATIONS INTERFACE (SCI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
36
48
48
48
49
54
5.5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.5.2 Main Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.5.3 General Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.5.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.5.5 Low Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.5.6 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.5.7 Register Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.6 USB INTERFACE (USB) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
54
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56
60
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61
65
5.6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.6.2 Main Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.6.3 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.6.4 Register Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.6.5 Programming Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.7 I²C BUS INTERFACE (I²C) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
65
65
65
66
71
73
5.7.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.7.2 Main Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.7.3 General Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.7.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.7.5 Low Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.7.6 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.7.7 Register Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.8 8-BIT A/D CONVERTER (ADC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
73
73
73
75
78
78
79
84
5.8.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.8.2 Main Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.8.3 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.8.4 Low Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.8.5 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.8.6 Register Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6 INSTRUCTION SET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.1 ST7 ADDRESSING MODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
84
84
85
85
85
86
87
87
6.1.1 Inherent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.1.2 Immediate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.1.3 Direct . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.1.4 Indexed (No Offset, Short, Long) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.1.5 Indirect (Short, Long) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.1.6 Indirect Indexed (Short, Long) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.1.7 Relative Mode (Direct, Indirect) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.2 INSTRUCTION GROUPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
88
88
88
88
88
89
89
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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ST7263
1 GENERAL DESCRIPTION
1.1 INTRODUCTION
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
– industry standard asynchronous SCI serial interface (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 capabilities
– fast I2C Multi Master interface (not on all products - see device summary)
– Low voltage (LVD) reset ensuring proper poweron 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 VPP/TEST
pin.
Figure 1. General Block Diagram
Internal
CLOCK
OSC/3
OSCIN
OSCOUT
OSCILLATOR
I2C*
OSC/4 or OSC/2
(for USB)
VDD
VSS
PORT A
POWER
SUPPLY
PA[7:0]
(8 bits)
16-BIT TIMER
WATCHDOG
CONTROL
8-BIT CORE
ALU
LVD
USB DMA
VPP/TEST
VDDA
VSSA
PROGRAM
MEMORY
(4K/8K/16K Bytes)
ADDRESS AND DATA BUS
RESET
PORT B
ADC
PB[7:0]
(8 bits)
PORT C
SCI*
(UART)
USB SIE
PC[2:0]
(3 bits)
USBDP
USBDM
USBVCC
RAM
(256/512 Bytes)
* not on all products (refer to Table 1: Device Summary)
5/109
ST7263
1.2 PIN DESCRIPTION
Figure 2. 34-Pin SO Package Pinout
VDD
1
34
VDDA
OSCOUT
OSCIN
2
33
3
32
USBVCC
USBDM
VSS
4
31
USBDP
PC2/USBOE
5
30
PC1/TDO
6
29
VSSA
PA0/MCO
PC0/RDI
7
28
PA1(25mA)/SDA
RESET
8
27
NC
NC
9
26
NC
AIN7/IT8/PB7(10mA)
AIN6/IT7/PB6(10mA)
10
25
NC
11
24
PA2(25mA)/SCL
VPP/TEST
AIN5/IT6/PB5(10mA)
12
23
PA3/EXTCLK
13
22
AIN4/IT5/PB4(10mA)
14
21
PA4/ICAP1/IT1
PA5/ICAP2/IT2
AIN3/PB3(10mA)
15
20
AIN2/PB2(10mA)
16
19
PA6/OCMP1/IT3
PA7/OCMP2/IT4
AIN1/PB1(10mA)
17
18
PB0(10mA)/AIN0
* VPP on EPROM/OTP versions only
Figure 3. 32-Pin SDIP Package Pinout
VDD
1
32
VDDA
OSCOUT
2
31
USBVCC
OSCIN
3
30
USBDM
USBDP
VSSA
VSS
4
29
PC2/USBOE
5
28
PC1/TDO
PC0/RDI
RESET
6
27
7
26
8
25
AIN7/IT8/PB7(10mA)
AIN6/IT7/PB6(10mA)
VPP/TEST*
9
24
10
23
NC
NC
PA2(25mA)/SCL
11
22
PA3/EXTCLK
AIN5/IT6/PB5(10mA)
12
21
AIN4/IT5/PB4(10mA)
13
20
AIN3/PB3(10mA)
14
19
PA4/ICAP1/IT1
PA5/ICAP2/IT2
PA6/COMP1/IT3
AIN2/PB2(10mA)
15
18
PA7/COMP2/IT4
AIN1/PB1/(10mA)
16
17
PB0(10mA)/AIN0
* VPP on EPROM/OTP versions only
6/109
PA0/MCO
PA1(25mA)/SDA
ST7263
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 VDD is low. It can be used to reset external peripherals.
OSCIN/OSCOUT: Input/Output Oscillator pin.
These pins connect a parallel-resonant crystal, or
an external source to the on-chip oscillator.
VPP/TEST: EPROM programming input. This pin
must be held low during normal operating modes.
VDD/VSS (see Note 2): Main power supply and
Ground voltages.
VDDA/VSSA (see Note 2): Power Supply and
Ground for analog peripherals.
Alternate Functions: Several pins of the I/O ports
assume software programmable alternate functions as shown in the pin description.
Note 1: Adding two 100nF decoupling capacitors
on Reset pin (respectively connected to VDD and
VSS) will significantly improve product electromagnetic susceptibility performances.
Note 2: To enhance reliability of operation, it is
recommended to connect VDDA and VDD together
on the application board. The same recommendations apply to VSSA and VSS.
Table 2. Device Pin Description
Level
Port / Control
Output
Main
Function
(after reset)
OSCOUT
O
Oscillator output
3
3
OSCIN
I
Oscillator input
4
4
VSS
S
Digital ground
5
5
PC2/USBOE
I/O
CT
X
X
Port C2
USB Output Enable
6
6
PC1/TDO
I/O
CT
X
X
Port C1
SCI transmit data output *)
7
7
PC0/RDI
I/O
CT
X
X
Port C0
SCI Receive Data Input *)
8
8
RESET
I/O
--
9
NC
9
10 PB7/AIN7/IT8
I/O CT 10mA X
X
X
X
Port B7
ADC analog input 7
10 11 PB6/AIN6/IT7
I/O CT 10mA X
X
X
X
Port B6
ADC analog input 6
11 12 VPP/TEST
X
PP
2
OD
2
ana
Power supply voltage (4V - 5.5V)
int
S
wpu
VDD
float
1
Output
1
Pin Name
Input
SO34
Input
SDIP32
Type
Pin n°
X
Alternate Function
Reset
--
Not connected
S
Supply for EPROM and test input
12 13 PB5/AIN5/IT6
I/O CT 10mA X
X
X
X
Port B5
ADC analog input 5
13 14 PB4/AIN4/IT5
I/O CT 10mA X
X
X
X
Port B4
ADC analog input 4
14 15 PB3/AIN3
I/O CT 10mA X
X
X
Port B3
ADC analog input 3
15 16 PB2/AIN2
I/O CT 10mA X
X
X
Port B2
ADC analog input 2
16 17 PB1/AIN1
I/O CT 10mA X
X
X
Port B1
ADC analog input 1
17 18 PB0/AIN0
I/O CT 10mA X
X
X
Port B0
ADC Analog Input 0
18 19 PA7/OCMP2/IT4
I/O
CT
X
X
X
Port A7
Timer Output Compare 2
19 20 PA6/OCMP1/IT3
I/O
CT
X
X
X
Port A6
Timer Output Compare 1
7/109
ST7263
Port / Control
Input
Main
Function
(after reset)
Alternate Function
CT
X
X
X
Port A5
Timer Input Capture 2
21 22 PA4/ICAP1/IT1
I/O
CT
X
X
X
Port A4
Timer Input Capture 1
22 23 PA3/EXTCLK
I/O
CT
X
X
Port A3
Timer External Clock
23 24 PA2/SCL
I/O CT 25mA X
Port A2
I2C serial clock *)
PP
I/O
OD
20 21 PA5/ICAP2/IT2
ana
int
Output
wpu
float
Output
Type
SO34
SDIP32
Pin Name
Input
Level
Pin n°
T
-- 25 NC
--
Not connected
24 26 NC
--
Not connected
25 27 NC
--
Not connected
26 28 PA1/SDA
I/O CT 25mA X
27 29 PA0/MCO
I/O
28 30 VSSA
S
CT
T
X
X
Port A1
I2C serial data *)
Port A0
Main Clock Output
Analog ground
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 VDDA
S
Analog supply voltage
*: if the peripheral is present on the device (see Table 1 Device Summary)
Legend / Abbreviations for Figure 2 and Table 2:
Type:
I = input, O = output, S = supply
In/Output level: CT = 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
ST7263
1.3 EXTERNAL CONNECTIONS
The following figure shows the recommended external connections for the device.
The VPP 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.
The external reset network is intended to protect
the device against parasitic resets, especially in
noisy environments.
Unused I/Os should be tied high to avoid any unnecessary power consumption on floating lines.
An alternative solution is to program the unused
ports as inputs with pull-up.
Figure 4. Recommended External Connections
VPP
VDD
10nF
VDD
+
0.1µF
VSS
Optional if Low Voltage
Detector (LVD) is used
VDD
4.7K
0.1µF
RESET
EXTERNAL RESET CIRCUIT
0.1µF
See
Clocks
Section
OSCIN
OSCOUT
Or configure unused I/O ports
by software as input with pull-up
VDD
10K
Unused I/O
9/109
ST7263
1.4 REGISTER & MEMORY MAP
As shown in Figure 5, the MCU is capable of addressing 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.
The highest address bytes contain the user reset
and interrupt vectors.
IMPORTANT: Memory locations noted “Reserved” must never be accessed. Accessing a reserved area can have unpredictable effects on the
device
Figure 5. Memory Map
0000h
HW Registers
(see Table 4
003Fh
0040h
023Fh
0240h
0040h
Short Addressing
RAM (192 Bytes)
00FFh
0100h
256 Bytes RAM*
Stack (64 Bytes)
512 Bytes RAM*
013Fh
Reserved
0040h
BFFFh
C000h
Short Addressing
RAM (192 Bytes)
00FFh
0100h
Program Memory*
Stack (64 Bytes)
16K Bytes
013Fh
0140h
E000h
8K Bytes
16-bit Addressing RAM
(256 Bytes)
F000h
4K Bytes
023Fh
FFEFh
FFF0h
FFFFh
Interrupt & Reset Vectors
(see Table 3 on page 10)
* 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
USB Interrupt Vector
I- bit
Internal Interrupt
No
FFF2-FFF3h
SCI Interrupt Vector*
I- bit
Internal Interrupt
No
FFF4-FFF5h
I2C Interrupt Vector*
I- bit
Internal Interrupt
No
FFF6-FFF7h
TIMER Interrupt Vector
I- bit
Internal Interrupt
No
FFF8-FFF9h
IT1 to IT8 Interrupt Vector
I- bit
External Interrupts
Yes
Yes
FFFA-FFFBh
USB End Suspend Mode Interrupt Vector
I- bit
Internal Interrupt
FFFC-FFFDh
TRAP (software) Interrupt Vector
none
CPU Interrupt
FFFE-FFFFh
RESET Vector
none
* If the peripheral is present on the device (see Table 1 Device Summary)
10/109
No
Yes
ST7263
Table 4. Hardware Register Memory Map
Address
Block
Register Label
Register name
Reset Status
Remarks
0000h
PADR
Port A Data Register
00h
R/W
0001h
PADDR
Port A Data Direction Register
00h
R/W
0002h
PBDR
Port B Data Register
00h
R/W
0003h
PBDDR
Port B Data Direction Register
00h
R/W
0004h
PCDR
Port C Data Register
1111 x000b
R/W
0005h
PCDDR
Port C Data Direction Register
1111 x000b
R/W
0006h
Reserved (2 Bytes)
0007h
0008h
ITIFRE
Interrupt Register
00h
R/W
0009h
MISCR
Miscellaneous Register
F0h
R/W
DR
ADC Data Register
00h
Read only
CSR
ADC control Status register
00h
R/W
CR
Watchdog Control Register
7Fh
R/W
000Ah
000Bh
000Ch
ADC
WDG
000Dh
Reserved (4 Bytes)
0010h
0011h
CR2
Timer Control Register 2
00h
R/W
0012h
CR1
Timer Control Register 1
00h
R/W
0013h
SR
Timer Status Register
00h
Read only
0014h
IC1HR
Timer Input Capture High Register 1
xxh
Read only
0015h
IC1LR
Timer Input Capture Low Register 1
xxh
Read only
0016h
OC1HR
Timer Output Compare High Register 1
80h
R/W
0017h
OC1LR
Timer Output Compare Low Register 1
00h
R/W
CHR
Timer Counter High Register
FFh
Read only
0019h
CLR
Timer Counter Low Register
FCh
R/W
001Ah
ACHR
Timer Alternate Counter High Register
FFh
Read only
001Bh
ACLR
Timer Alternate Counter Low Register
FCh
R/W
001Ch
IC2HR
Timer Input Capture High Register 2
xxh
Read only
001Dh
IC2LR
Timer Input Capture Low Register 2
xxh
Read only
001Eh
OC2HR
Timer Output Compare High Register 2
80h
R/W
001Fh
OC2LR
Timer Output Compare Low Register 2
00h
R/W
0020h
SR
SCI Status Register
C0h
Read only
0021h
DR
SCI Data Register
xxh
R/W
0018h
TIM
SCI 1)
BRR
SCI Baud Rate Register
00xx xxxxb
R/W
0023h
CR1
SCI Control Register 1
xxh
R/W
0024h
CR2
SCI Control Register 2
00h
R/W
0022h
11/109
ST7263
Address
Block
Register Label
Register name
Reset Status
Remarks
0025h
PIDR
USB PID Register
xxh
Read only
0026h
DMAR
USB DMA address Register
xxh
R/W
0027h
IDR
USB Interrupt/DMA Register
xxh
R/W
0028h
ISTR
USB Interrupt Status Register
00h
R/W
0029h
IMR
USB Interrupt Mask Register
00h
R/W
002Ah
CTLR
USB Control Register
xxxx 0110b
R/W
DADDR
USB Device Address Register
00h
R/W
002Ch
EP0RA
USB Endpoint 0 Register A
0000 xxxxb
R/W
002Dh
EP0RB
USB Endpoint 0 Register B
80h
R/W
002Eh
EP1RA
USB Endpoint 1 Register A
0000 xxxxb
R/W
002Fh
EP1RB
USB Endpoint 1 Register B
0000 xxxxb
R/W
0030h
EP2RA
USB Endpoint 2 Register A
0000 xxxxb
R/W
0031h
EP2RB
USB Endpoint 2 Register B
0000 xxxxb
R/W
I2C Data Register
00h
R/W
Reserved
-
002Bh
USB
0032h
Reserved (7 Bytes)
0038h
DR
0039h
003Ah
I2C1)
003Bh
OAR
I2C (7 Bits) Slave Address Register
00h
R/W
003Ch
CCR
I2C Clock Control Register
00h
R/W
2
003Dh
SR2
I C 2nd Status Register
00h
Read only
003Eh
SR1
I2C 1st Status Register
00h
Read only
003Fh
CR
I2C Control Register
00h
R/W
Note 1. If the peripheral is present on the device (see Table 1 Device Summary)
12/109
ST7263
1.5 EPROM/OTP PROGRAM MEMORY
The program memory of the ST72T63 may be programmed using the EPROM programming boards
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 to 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 IDD in
power-saving modes due to photo-diode leakage
currents.
An Ultraviolet source of wave length 2537 Å yielding a total integrated dosage of 15 Watt-sec/cm2 is
required to erase the ST72Exxx. The device will
be erased in 15 to 30 minutes if such a UV lamp
with a 12mW/cm2 power rating is placed 1 inch
from the device window without any interposed filters.
13/109
ST7263
2 CENTRAL PROCESSING 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 power 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.
Accumulator (A)
The Accumulator is an 8-bit general purpose register used to hold operands and the results of the
arithmetic and logic calculations and to manipulate
data.
Index Registers (X and Y)
In indexed addressing modes, these 8-bit registers
are used to create either effective addresses or
temporary storage areas for data manipulation.
(The Cross-Assembler generates a precede instruction (PRE) to indicate that the following instruction refers to the Y register.)
The Y register is not affected by the interrupt automatic procedures (not pushed to and popped from
the stack).
Program Counter (PC)
The program counter is a 16-bit register containing
the address of the next instruction to be executed
by the CPU. It is made of two 8-bit registers PCL
(Program Counter Low which is the LSB) and PCH
(Program Counter High which is the MSB).
Figure 6. CPU Registers
7
0
ACCUMULATOR
RESET VALUE = XXh
7
0
X INDEX REGISTER
RESET VALUE = XXh
7
0
Y INDEX REGISTER
RESET VALUE = XXh
15
PCH
8 7
PCL
0
PROGRAM COUNTER
RESET VALUE = RESET VECTOR @ FFFEh-FFFFh
7
1 1 1 H I
0
N Z C
CONDITION CODE REGISTER
RESET VALUE = 1 1 1 X 1 X X X
15
8 7
0
STACK POINTER
RESET VALUE = STACK HIGHER ADDRESS
X = Undefined Value
14/109
ST7263
CPU REGISTERS (Cont’d)
CONDITION CODE REGISTER (CC)
Read/Write
Reset Value: 111x1xxx
7
1
0
1
1
H
I
N
Z
because the I bit is set by hardware at the start of
the routine and reset by the IRET instruction at the
end of the routine. If the I bit is cleared by software
in the interrupt routine, pending interrupts are
serviced regardless of the priority level of the current interrupt routine.
C
The 8-bit Condition Code register contains the interrupt mask and four flags representative of the
result of the instruction just executed. This register
can also be handled by the PUSH and POP instructions.
These bits can be individually tested and/or controlled by specific instructions.
Bit 4 = H Half carry.
This bit is set by hardware when a carry occurs between bits 3 and 4 of the ALU during an ADD or
ADC 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 2 = N Negative.
This bit is set and cleared by hardware. It is representative of the result sign of the last arithmetic,
logical or data manipulation. It is a copy of the 7th
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 instructions.
Bit 1 = Z Zero.
This bit is set and cleared by hardware. This bit indicates that the result of the last arithmetic, logical
or data manipulation is zero.
0: The result of the last operation is different from
zero.
1: The result of the last operation is zero.
This bit is accessed by the JREQ and JRNE test
instructions.
Bit 3 = I Interrupt mask.
This bit is set by hardware when entering in interrupt or by software to disable all interrupts except
the TRAP software interrupt. This bit is cleared by
software.
0: Interrupts are enabled.
1: Interrupts are disabled.
This bit is controlled by the RIM, SIM and IRET instructions and is tested by the JRM and JRNM instructions.
Note: Interrupts requested while I is set are
latched and can be processed when I is cleared.
By default an interrupt routine is not interruptable
Bit 0 = C Carry/borrow.
This bit is set and cleared by hardware and software. It indicates an overflow or an underflow has
occurred during the last arithmetic operation.
0: No overflow or underflow has occurred.
1: An overflow or underflow has occurred.
This bit is driven by the SCF and RCF instructions
and tested by the JRC and JRNC instructions. It is
also affected by the “bit test and branch”, shift and
rotate instructions.
15/109
ST7263
CPU REGISTERS (Cont’d)
Stack Pointer (SP)
Read/Write
Reset Value: 01 3Fh
15
0
8
0
0
0
0
0
0
7
0
1
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 hardware. Following an
MCU Reset, or after a Reset Stack Pointer 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, without indicating the stack overflow. The previously
stored information is then overwritten and therefore lost. The stack also wraps in case of an underflow.
The stack is used to save the return address during a subroutine call and the CPU context during
an interrupt. The user may also directly manipulate
the stack by means of the PUSH and POP instructions. In the case of an interrupt, the PCL is stored
at the first location pointed to by the SP. Then the
other registers are stored in the next locations as
shown in Figure 7.
– When an interrupt is received, the SP is decremented and the context is pushed on the stack.
– On return from interrupt, the SP is incremented
and the context is popped from the stack.
A subroutine call occupies two locations and an interrupt five locations in the stack area.
Figure 7. Stack Manipulation Example
CALL
Subroutine
PUSH Y
Interrupt
Event
POP Y
RET
or RSP
IRET
@ 0100h
SP
SP
CC
A
X
X
X
PCH
PCH
PCH
PCL
PCL
PCL
PCH
PCH
PCH
PCH
PCH
PCL
PCL
PCL
PCL
PCL
SP
@ 013Fh
Stack Higher Address = 013Fh
Stack Lower Address = 0100h
16/109
SP
Y
CC
A
CC
A
SP
SP
ST7263
3 CLOCKS AND RESET
3.1 CLOCK SYSTEM
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 (fCPU) is derived from the external oscillator frequency (fOSC),
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 (fCPU) is also routed to
the on-chip peripherals. The CPU clock signal
consists of a square wave with a duty cycle of
50%.
The internal oscillator is designed to operate with
an AT-cut parallel resonant quartz or ceramic resonator in the frequency range specified for fosc.
The circuit shown in Figure 9 is recommended
when using a crystal, and Table 5 Recommended
Values for 24 MHz Crystal Resonator lists the recommended 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.
Table 5. Recommended Values for 24 MHz
Crystal Resonator
RSMAX
20 Ω
25 Ω
70 Ω
COSCIN
56pF
47pF
22pF
COSCOUT
56pF
47pF
22pF
RP
1-10 MΩ
1-10 MΩ
1-10 MΩ
Figure 8. External Clock Source Connections
OSCIN
NC
EXTERNAL
CLOCK
Figure 9. Crystal/Ceramic Resonator
OSCOUT
OSCIN
RP
COSCIN
COSCOUT
Figure 10. Clock block diagram
8 or 4 MHz
CPU and
peripherals)
%3
Note: RSMAX is the equivalent serial resistor of the
crystal (see crystal specification).
3.1.2 External Clock
An external clock may be applied to the OSCIN input with the OSCOUT pin not connected, as
shown on Figure 8. The tOXOV specifications does
not apply when using an external clock input. The
equivalent specification of the external clock
source should be used instead of t OXOV (see Section 6.5 CONTROL TIMING).
OSCOUT
CLKDIV
1
24 or
12 MHz
Crystal
6 MHz (USB)
%2
%2
%2
0
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
active.
3.2.1 Low Voltage Detector (LVD)
Low voltage reset circuitry generates a reset when
VDD is:
■ below VIT+ when VDD is rising,
■ below VIT- when VDD is falling.
During low voltage reset, the RESET pin is held low,
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 pin is
pulled low permitting the MCU to reset other devices in the same way as the low voltage reset (Figure 11).
3.2.3 External Reset
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 provided to improve noise immunity.
Table 6. List of sections affected by RESET, WAIT and HALT (Refer to 3.5 for Wait and Halt Modes)
Section
RESET
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)
Reset HALT latch
WAIT
X
HALT
X
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
Figure 12. Low Voltage Reset Signal Output
RESET
VIT+
VDD
VIT-
LOW VOLTAGE
DETECTOR
INTERNAL
RESET
FROM
WATCHDOG
RESET
VDD
RESET
Note: Hysteresis (VIT+-VIT-) = Vhys
Figure 13. Temporization timing diagram after an internal Reset
VIT+
VDD
temporization (4096 CPU clock cycles)
Addresses
$FFFE
Figure 14. Reset Timing Diagram
tDDR
VDD
OSCIN
tOXOV
fCPU
PC
RESET
WATCHDOG RESET
FFFE
FFFF
4096 CPU
CLOCK
CYCLES
DELAY
Note: Refer to Electrical Characteristics for values of tDDR, tOXOV, VIT+, VIT- and Vhys
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 nonmaskable 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 subsection).
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 additional 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 causes the contents of the
saved registers to be recovered from the stack.
Note: As a consequence of the IRET instruction,
the I bit will be cleared and the main program will
resume.
Priority management
By default, a servicing interrupt 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.
20/109
Interrupts and Low power mode
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 the “Exit from HALT“
column in Table 7 Interrupt Mapping).
External interrupts
The pins ITi/PAk and ITj/PBk (i=1,2; j= 5,6; k=4,5)
can generate an interrupt 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 generate an interrupt when a falling edge occurs on this pin.
Interrupt generation will occur if it is enabled 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
register.
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
register or
– 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.
ST7263
INTERRUPTS (Cont’d)
Figure 15. Interrupt Processing Flowchart
FROM RESET
BIT I SET
N
N
Y
Y
FETCH NEXT INSTRUCTION
N
INTERRUPT
IRET
STACK PC, X, A, CC
SET I BIT
LOAD PC FROM INTERRUPT VECTOR
Y
EXECUTE INSTRUCTION
RESTORE PC, X, A, CC FROM STACK
THIS CLEARS I BIT BY DEFAULT
Table 7. Interrupt Mapping
N°
Source
Block
RESET
TRAP
USB
1
ITi
2
TIMER
3
I2C
Description
Reset
Software Interrupt
End Suspend Mode
External Interrupts
Timer Peripheral Interrupts
I2C Peripheral Interrupts
Register
Label
Priority
Order
N/A
Highest
Priority
ISTR
Address
yes
FFFEh-FFFFh
no
FFFCh-FFFDh
yes
ITRFRE
TIMSR
SCI Peripheral Interrupts
SCISR
5
USB
USB Peripheral Interrupts
ISTR
FFF8h-FFF9h
FFF4h-FFF5h
I2CSR2
SCI
FFFAh-FFFBh
FFF6h-FFF7h
I2CSR1
4
Vector
Exit
from
HALT
no
Lowest
Priority
FFF2h-FFF3h
FFF0h-FFF1h
21/109
ST7263
INTERRUPTS (Cont’d)
4.1.1 Interrupt Register
INTERRUPTS REGISTER (ITRFRE)
Address: 0008h — Read/Write
Reset Value: 0000 0000 (00h)
7
IT8E
0
IT7E
IT6E
IT5E
IT4E
IT3E
IT2E
IT1E
Bit 7:0 = ITiE (i=1 to 8). Interrupt Enable Control
Bits .
22/109
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.
ST7263
4.2 POWER SAVING MODES
4.2.1 Introduction
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 USB end suspend mode),
are allowed and if an interrupt occurs, the CPU
clock becomes active.
The MCU can exit HALT mode on reception of either an external interrupt on ITi, an end suspend
mode interrupt coming from USB peripheral, or a
reset. The oscillator is then turned on and a stabilization time is provided before releasing 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. HALT Mode Flow Chart
HALT INSTRUCTION
OSCILLATOR
PERIPH. CLOCK
CPU CLOCK
OFF
OFF
OFF
CLEARED
I-BIT
N
RESET
N
EXTERNAL
INTERRUPT*
Y
Y
OSCILLATOR
PERIPH. CLOCK
CPU CLOCK
I-BIT
ON
ON
ON
SET
4096 CPU CLOCK
CYCLES DELAY
FETCH RESET VECTOR
OR SERVICE INTERRUPT
Note: Before servicing an interrupt, the CC register is
pushed on the stack. The I-Bit is set during 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 power saving mode is selected by calling 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 memory remain unchanged. The MCU remains in WAIT
mode until an interrupt or Reset occurs, whereupon the Program Counter branches to the starting
address of the interrupt or Reset service routine.
The MCU will remain in WAIT mode until a Reset
or an Interrupt occurs, causing it to wake up.
Refer to Figure 17.
WFI INSTRUCTION
OSCILLATOR
PERIPH. CLOCK
CPU CLOCK
I-BIT
ON
ON
OFF
CLEARED
N
RESET
N
Y
INTERRUPT
Y
OSCILLATOR
PERIPH. CLOCK
CPU CLOCK
I-BIT
ON
ON
ON
SET
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 stack. The I-Bit is set during the interrupt routine and cleared when the CC register is
popped.
24/109
ST7263
5 ON-CHIP PERIPHERALS
5.1 I/O PORTS
5.1.1 Introduction
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 peripherals.
– external interrupt generation
An I/O port is composed of up to 8 pins. Each pin
can be programmed independently as digital input
(with or without interrupt generation) or digital output.
5.1.2 Functional description
Each port is associated to 2 main registers:
– Data Register (DR)
– Data Direction Register (DDR)
Each I/O pin may be programmed using the corresponding 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 Functions
DDR
MODE
0
Input
1
Output
Input Modes
The input configuration is selected 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
trigger.
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 to 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 Function
When an on-chip peripheral is configured to use a
pin, the alternate function is automatically 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 going to an on-chip peripheral,
the I/O pin has to be configured in input mode. In
this case, the pin’s state is also digitally readable
by addressing the DR register.
Notes:
1. Input pull-up configuration can cause an unexpected 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 function must not be activated 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 on the selected pin to
the common analog rail which is connected 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 is recommended not to
26/109
have clocking pins located close to a selected analog pin.
Warning: The analog input voltage level must be
within the limits stated in the Absolute Maximum
Ratings.
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.
ST7263
I/O PORTS (Cont’d)
5.1.4 Port A
Table 9. Port A0, A3, A4, A5, A6, A7 Description
I/O
PORT A
Alternate Function
Input*
Output
Signal
Condition
PA0
with pull-up
push-pull
MCO (Main Clock Output)
PA3
with pull-up
push-pull
Timer EXTCLK
PA4
with pull-up
PA5
with pull-up
PA6
with pull-up
PA7
with pull-up
MCO = 1 (MISCR)
CC1 =1
CC0 = 1 (Timer CR2)
Timer ICAP1
push-pull
IT1 Schmitt triggered input
IT1E = 1 (ITIFRE)
Timer ICAP2
push-pull
push-pull
push-pull
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)
*Reset State
Figure 18. PA0, PA3, PA4, PA5, PA6, PA7 Configuration
ALTERNATE ENABLE
VDD
ALTERNATE 1
OUTPUT
0
P-BUFFER
VDD
DR
PULL-UP
DATA BUS
LATCH
ALTERNATE ENABLE
DDR
LATCH
PAD
DDR SEL
N-BUFFER
DR SEL
ALTERNATE INPUT
1
0
DIODES
ALTERNATE ENABLE
VSS
CMOS SCHMITT TRIGGER
27/109
ST7263
I/O PORTS (Cont’d)
Table 10. PA1, PA2 Description
PORT A
I/O
Alternate Function
Input*
Output
Signal
Condition
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 1
OUTPUT
0
DR
LATCH
DDR
LATCH
DATA BUS
PAD
DDR SEL
N-BUFFER
DR SEL
1
ALTERNATE ENABLE
VSS
0
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)
Analog input (ADC)
CH[2:0]= 100 (ADCCSR)
PB4
without pull-up
push-pull
IT5 Schmitt triggered input
IT4E = 1 (ITIFRE)
Analog input (ADC)
CH[2:0]= 101 (ADCCSR)
IT6 Schmitt triggered input
IT5E = 1 (ITIFRE)
Analog input (ADC)
CH[2:0]= 110 (ADCCSR)
IT7 Schmitt triggered input
IT6E = 1 (ITIFRE)
Analog input (ADC)
CH[2:0]= 111 (ADCCSR)
IT8 Schmitt triggered input
IT7E = 1 (ITIFRE)
PB5
without pull-up
PB6
push-pull
without pull-up
PB7
push-pull
without pull-up
push-pull
*Reset State
Figure 20. Port B Configuration
ALTERNATE ENABLE
ALTERNATE
OUTPUT
V DD
1
0
P-BUFFER
DR
LATCH
VDD
ALTERNATE ENABLE
DDR
PAD
LATCH
DATA BUS
COMMON ANALOG RAIL
ANALOG ENABLE
(ADC)
DDR SEL
ANALOG
SWITCH
DIODES
N-BUFFER
DR SEL
1
ALTERNATE ENABLE
0
DIGITAL ENABLE
V SS
ALTERNATE INPUT
29/109
ST7263
I/O PORTS (Cont’d)
5.1.6 Port C
Table 12. Port C Description
I/O
Alternate Function
PORT C
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. Port C Configuration
ALTERNATE ENABLE
VDD
ALTERNATE 1
OUTPUT
0
P-BUFFER
DR
PULL-UP
LATCH
VDD
ALTERNATE ENABLE
DATA BUS
DDR
PAD
LATCH
DDR SEL
N-BUFFER
DR SEL
1
0
DIODES
ALTERNATE ENABLE
VSS
ALTERNATE INPUT
CMOS SCHMITT TRIGGER
30/109
ST7263
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: for Port C, unused bits (7-3) are not accessible.
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 accessible
7
7
0
0
DD7
D7
D6
D5
D4
D3
D2
D1
DD6
DD5
DD4
DD3
DD2
DD1
DD0
D0
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
even if the pin is configured as an input. Reading
the DR register returns either the DR register latch
content (pin configured as output) or the digital value applied to the I/O pin (pin configured as input).
Bit 7:0 = DD7-DD0 Data Direction Register 8 bits.
The DDR register gives the input/output direction
configuration of the pins. Each bits is set and
cleared by software.
0: Input mode
1: Output mode
Table 13. I/O Ports Register Map
Address
(Hex.)
00
01
02
03
04
05
Register
Label
7
PADR
PADDR
PBDR
PBDDR
PCDR
PCDDR
MSB
MSB
MSB
MSB
MSB
MSB
6
5
4
3
2
1
0
LSB
LSB
LSB
LSB
LSB
LSB
31/109
ST7263
5.2 MISCELLANEOUS REGISTER
Address: 0009h — Read/Write
Reset Value: 1111 0000 (F0h)
7
-
0
-
-
-
LVD
CLKDIV USBOE
MCO
Bit 7:4 = Reserved
Bit 3 = LVD Low Voltage Detector.
This bit is set by software and only cleared by hardware after a reset.
0: LVD enabled
1: LVD disabled
32/109
Bit 2 = CLKDIV Clock Divider.
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 oscillator (refer to Figure 10
on page 17).
0: 24 MHz external oscillator
1: 12 MHz external oscillator.
Bit 1 = USBOE USB enable.
If this bit is set, the port PC2 outputs the USB output enable signal (at “1” when the ST7 USB is
transmitting data).
Unused bits 7-4 are set.
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 (fCPU on I/O
port)
ST7263
5.3 WATCHDOG TIMER (WDG)
5.3.1 Introduction
The Watchdog timer is used to detect the occurrence of a software fault, usually generated by external interference or by unforeseen logical conditions, which causes the application program to
abandon its normal sequence. The Watchdog circuit generates an MCU reset on expiry of a programmed time period, unless the program refreshes the counter’s contents before the T6 bit becomes cleared.
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
Figure 22. Watchdog Block Diagram
RESET
WATCHDOG CONTROL REGISTER (CR)
WDGA
T6
T5
T4
T3
T2
T1
T0
7-BIT DOWNCOUNTER
fCPU
CLOCK DIVIDER
÷49152
33/109
ST7263
WATCHDOG TIMER (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 be
programmed by the user in 64 increments.
If the watchdog is activated (the WDGA bit is set)
and when the 7-bit timer (bits T6:T0) rolls over
from 40h to 3Fh (T6 becomes cleared), it initiates
a reset cycle pulling low the reset pin for typically
500ns.
The application program must write in the CR register at regular intervals during normal operation to
prevent an MCU reset. The value to be 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 immediate 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 (fCPU = 8 MHz)
CR Register
initial value
WDG timeout period
(ms)
Max
FFh
393.216
Min
C0h
6.144
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 generate a software 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 stops counting
and is no longer able to generate a reset until 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
– Make sure that an external event is available to
wake up the microcontroller from Halt mode.
– Before executing the HALT instruction, refresh
the WDG counter, to avoid an unexpected WDG
34/109
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 sensitiveness of each external interrupt as a precautionary measure.
– The opcode for the HALT instruction is 0x8E. To
avoid an unexpected HALT instruction due to a
program counter failure, it is advised to clear all
occurrences of the data value 0x8E from memory. For example, avoid defining a constant in
ROM with the value 0x8E.
– As the HALT instruction clears the I bit in the CC
register to allow interrupts, the user may choose
to clear all pending interrupt bits before executing the HALT instruction. This avoids entering
other peripheral interrupt routines after executing
the external interrupt routine corresponding to
the wake-up event (reset or external interrupt).
5.3.4 Interrupts
None.
5.3.5 Register Description
CONTROL REGISTER (CR)
Read /Write
Reset Value: 0111 1111 (7Fh)
7
WDGA
0
T6
T5
T4
T3
T2
T1
T0
Bit 7 = WDGA Activation bit.
This bit is set by software and only cleared by
hardware after a reset. When WDGA = 1, the
watchdog can generate a reset.
0: Watchdog disabled
1: Watchdog enabled
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).
ST7263
WATCHDOG TIMER (Cont’d)
Table 15. Watchdog Timer Register Map and Reset Values
Address
(Hex.)
0C
Register
Label
7
6
5
4
3
2
1
0
WDGCR
WDGA
T6
T5
T4
T3
T2
T1
T0
Reset Value
0
1
1
1
1
1
1
1
35/109
ST7263
5.4 16-BIT TIMER
5.4.1 Introduction
The timer consists of a 16-bit free-running counter
driven by a programmable prescaler.
It may be used for a variety of purposes, including
measuring the pulse lengths of up to two input signals ( input capture) or generating up to two output
waveforms (output compare and PWM ).
Pulse lengths and waveform periods can be modulated from a few microseconds to several milliseconds using the timer prescaler and the CPU
clock prescaler.
Some ST7 devices have two on-chip 16-bit timers.
They are completely independent, and do not
share any resources. They are synchronized after
a MCU reset as long as the timer clock frequencies are not modified.
This description covers one or two 16-bit timers. In
ST7 devices with two timers, register names are
prefixed with TA (Timer A) or TB (Timer B).
5.4.2 Main Features
■ Programmable prescaler: fCPU divided by 2, 4 or 8.
■ Overflow status flag and maskable interrupt
■ External clock input (must be at least 4 times
slower than the CPU clock speed) with the choice
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)*
The Block Diagram is shown in Figure 1.
*Note: Some timer pins may not be available (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
5.4.3 Functional Description
5.4.3.1 Counter
The main block of the Programmable Timer is a
16-bit free running upcounter and its associated
16-bit registers. The 16-bit registers are made up
of two 8-bit registers called high & low.
Counter Register (CR):
– Counter High Register (CHR) is the most significant byte (MS Byte).
– Counter Low Register (CLR) is the least significant byte (LS Byte).
Alternate Counter Register (ACR)
– Alternate Counter High Register (ACHR) is the
most significant byte (MS Byte).
– Alternate Counter Low Register (ACLR) is the
least significant byte (LS Byte).
These two read-only 16-bit registers contain the
same value but with the difference that reading the
ACLR register does not clear the TOF bit (Timer
overflow flag), located in the Status register (SR).
(See note at the end of paragraph titled 16-bit read
sequence).
Writing in the CLR register or ACLR register resets
the free running counter to the FFFCh value.
Both counters have a reset value of FFFCh (this is
the only value which is reloaded in the 16-bit timer). The reset value of both counters is also
FFFCh in One Pulse mode and PWM mode.
The timer clock depends on the clock control bits
of the CR2 register, as illustrated in Table 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 can be fCPU/2, fCPU/4, fCPU/8
or an external frequency.
ST7263
16-BIT TIMER (Cont’d)
Figure 23. Timer Block Diagram
ST7 INTERNAL BUS
fCPU
MCU-PERIPHERAL INTERFACE
8 low
8
8
8
low
8
high
8
low
8
high
EXEDG
8
low
high
8
high
8-bit
buffer
low
8 high
16
1/2
1/4
1/8
OUTPUT
COMPARE
REGISTER
2
OUTPUT
COMPARE
REGISTER
1
COUNTER
REGISTER
ALTERNATE
COUNTER
REGISTER
EXTCLK
pin
INPUT
CAPTURE
REGISTER
1
INPUT
CAPTURE
REGISTER
2
16
16
16
CC[1:0]
TIMER INTERNAL BUS
16 16
OVERFLOW
DETECT
CIRCUIT
OUTPUT COMPARE
CIRCUIT
6
ICF1 OCF1 TOF ICF2 OCF2 0
0
EDGE DETECT
CIRCUIT1
ICAP1
pin
EDGE DETECT
CIRCUIT2
ICAP2
pin
LATCH1
OCMP1
pin
LATCH2
OCMP2
pin
0
(Status Register) SR
ICIE OCIE TOIE FOLV2 FOLV1 OLVL2 IEDG1 OLVL1
(Control Register 1) CR1
OC1E OC2E OPM PWM
CC1
CC0 IEDG2 EXEDG
(Control Register 2) CR2
(See note)
TIMER INTERRUPT
Note: If IC, OC and TO interrupt requests have separate vectors
then the last OR is not present (See device Interrupt Vector Table)
37/109
ST7263
16-BIT TIMER (Cont’d)
16-bit Read Sequence: (from either the Counter
Register or the Alternate Counter Register).
Beginning of the sequence
At t0
Read
MS Byte
LS Byte
is buffered
Other
instructions
Read
At t0 +∆t LS Byte
Returns the buffered
LS Byte value at t0
Sequence completed
The user must read the MS Byte first, then the LS
Byte value is buffered automatically.
This buffered value remains unchanged until the
16-bit read sequence is completed, even if the
user reads the MS Byte several times.
After a complete reading sequence, if only the
CLR register or ACLR register are read, they return the LS Byte of the count value at the time of
the read.
Whatever the timer mode used (input capture, output compare, One Pulse mode or PWM mode) an
overflow occurs when the counter rolls over from
FFFFh to 0000h then:
– The TOF bit of the SR register is set.
– A timer interrupt is generated if:
– TOIE bit of the CR1 register is set and
– I bit of the CC register is cleared.
If one of these conditions is false, the interrupt remains pending to be issued as soon as they are
both true.
38/109
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. Counting 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 (where available) is selected if
CC0=1 and CC1=1 in the CR2 register.
The status of the EXEDG bit in the CR2 register
determines the type of level transition on the external clock pin EXTCLK that will trigger the free running counter.
The counter is synchronised with the falling edge
of the internal CPU clock.
A minimum of four falling edges of the CPU clock
must occur between two consecutive active edges
of the external clock; thus the external clock frequency must be less than a quarter of the CPU
clock frequency.
ST7263
16-BIT TIMER (Cont’d)
Figure 24. Counter Timing Diagram, internal clock divided by 2
CPU CLOCK
INTERNAL RESET
TIMER CLOCK
FFFD FFFE FFFF 0000
COUNTER REGISTER
0001
0002
0003
TIMER OVERFLOW FLAG (TOF)
Figure 25. Counter Timing Diagram, internal clock divided by 4
CPU CLOCK
INTERNAL RESET
TIMER CLOCK
COUNTER REGISTER
FFFC
FFFD
0000
0001
TIMER OVERFLOW FLAG (TOF)
Figure 26. Counter Timing Diagram, internal clock divided by 8
CPU CLOCK
INTERNAL RESET
TIMER CLOCK
COUNTER REGISTER
FFFC
FFFD
0000
TIMER OVERFLOW FLAG (TOF)
Note: The MCU is in reset state when the internal reset signal is high. When it is low, the MCU is running.
39/109
ST7263
16-BIT TIMER (Cont’d)
5.4.3.3 Input Capture
In this section, the index, i, may be 1 or 2 because
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 value of the free running counter after a transition is detected by the
ICAP i pin (see figure 5).
ICiR
MS Byte
ICiHR
LS Byte
ICiLR
The ICiR register is a read-only register.
The active transition is software programmable
through the IEDGi bit of Control Registers (CRi).
Timing resolution is one count of the free running
counter: (fCPU/CC[1:0]).
Procedure:
To use the input capture function, select the following in the CR2 register:
– Select the timer clock (CC[1:0]) (see Table 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 ICIE bit to generate an interrupt after an
input capture coming from either the ICAP1 pin
or the ICAP2 pin
– Select the edge of the active transition on the
ICAP1 pin with the IEDG1 bit (the ICAP1pin must
be configured as a floating input).
40/109
When an input capture occurs:
– The ICFi bit is set.
– The ICiR register contains the value of the free
running counter on the active transition on the
ICAPi pin (see Figure 6).
– A timer interrupt is generated if the ICIE bit is set
and the I bit is cleared in the CC register. Otherwise, the interrupt remains pending until both
conditions become true.
Clearing the Input Capture interrupt request (i.e.
clearing the ICFi bit) is done in two steps:
1. Reading the SR register while the ICFi bit is set.
2. An access (read or write) to the ICiLR register.
Notes:
1. After reading the ICiHR register, the transfer of
input capture data is inhibited and ICFi will
never be set until the ICiLR register is also
read.
2. The ICiR register contains the free running
counter value which corresponds to the most
recent input capture.
3. The 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 connected to the timer. So any
transitions on these pins activate the input capture function.
Moreover if one of the ICAPi pin is configured
as an input and the second one as an output,
an interrupt can be generated if the user toggles the output pin and if the ICIE bit is set.
This can be avoided if the input capture function i is disabled by reading the IC iHR (see note
1).
6. The TOF bit can be used with an interrupt in
order to measure events that exceed the timer
range (FFFFh).
ST7263
16-BIT TIMER (Cont’d)
Figure 27. Input Capture Block Diagram
ICAP1
pin
ICAP2
pin
(Control Register 1) CR1
EDGE DETECT
CIRCUIT2
EDGE DETECT
CIRCUIT1
ICIE
IEDG1
(Status Register) SR
IC1R Register
IC2R Register
ICF1
ICF2
0
0
0
(Control Register 2) CR2
16-BIT
16-BIT FREE RUNNING
CC1
CC0
IEDG2
COUNTER
Figure 28. Input Capture Timing Diagram
TIMER CLOCK
COUNTER REGISTER
FF01
FF02
FF03
ICAPi PIN
ICAPi FLAG
ICAPi REGISTER
FF03
Note: Active edge is rising edge.
41/109
ST7263
16-BIT TIMER (Cont’d)
5.4.3.4 Output Compare
In this section, the index, i, may be 1 or 2 because
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 between the Output Compare register and the free running counter, the output compare function:
– Assigns pins with a programmable value if the
OCIE bit is set
– Sets a flag in the status register
– Generates an interrupt if enabled
Two 16-bit registers Output Compare Register 1
(OC1R) and Output Compare Register 2 (OC2R)
contain the value to be compared to the counter
register each timer clock cycle.
OCiR
MS Byte
OCiHR
LS Byte
OCiLR
These registers are readable and writable and are
not affected by the timer hardware. A reset event
changes the OCiR value to 8000h.
Timing resolution is one count of the free running
counter: (fCPU/CC[1:0]).
Procedure:
To use the output compare function, select the following in the CR2 register:
– Set the OCiE bit if an output is needed then the
OCMPi pin is dedicated to the output compare i
signal.
– Select the timer clock (CC[1:0]) (see Table 1).
And select the following in the CR1 register:
– Select the OLVLi bit to applied to the OCMP i pins
after the match occurs.
– Set the OCIE bit to generate an interrupt if it is
needed.
When a match is found between OCRi register
and CR register:
– OCFi bit is set.
42/109
– The OCMP i 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 OCiR register value required for a specific timing application can be calculated using the following formula:
∆ OCiR =
∆t * fCPU
PRESC
Where:
∆t
= Output compare period (in seconds)
fCPU
= CPU clock frequency (in hertz)
PRESC = Timer prescaler factor (2, 4 or 8 depending on CC[1:0] bits, see Table 1)
If the timer clock is an external clock, the formula
is:
∆ OCiR = ∆t * fEXT
Where:
∆t
= Output compare period (in seconds)
= External timer clock frequency (in hertz)
fEXT
Clearing the output compare interrupt request (i.e.
clearing the OCFi bit) is done by:
1. Reading the SR register while the OCFi bit is
set.
2. An access (read or write) to the OCiLR register.
The following procedure is recommended to prevent the OCFi bit from being set between the time
it is read and the write to the OCiR register:
– Write to the OCiHR register (further compares
are inhibited).
– Read the SR register (first step of the clearance
of the OCFi bit, which may be already set).
– Write to the OCiLR register (enables the output
compare function and clears the OCFi bit).
ST7263
16-BIT TIMER (Cont’d)
Notes:
1. After a processor write cycle to the OCiHR register, the output compare function is inhibited
until the OCiLR register is also written.
2. If the OCiE bit is not set, the OCMPi pin is a
general I/O port and the OLVLi bit will not
appear when a match is found but an interrupt
could be generated if the OCIE bit is set.
3. When the timer clock is fCPU/2, OCFi and
OCMPi are set while the counter value equals
the OCiR register value (see Figure 8). This
behaviour is the same in OPM or PWM mode.
When the timer clock is fCPU/4, fCPU/8 or in
external clock mode, OCFi and OCMPi are set
while the counter value equals the OCiR register value plus 1 (see Figure 9).
4. The output compare functions can be used both
for generating external events on the OCMPi
pins even if the input capture mode is also
used.
5. The value in the 16-bit OCiR register and the
OLVi bit should be changed after each successful comparison in order to control an output
waveform or establish a new elapsed timeout.
Forced Compare Output capability
When the FOLVi bit is set by software, the OLVLi
bit is copied to the OCMPi pin. The OLVi bit has to
be toggled in order to toggle the OCMPi pin when
it is enabled (OCiE bit=1). The OCFi bit is then not
set by hardware, and thus no interrupt request is
generated.
FOLVLi bits have no effect in either One-Pulse
mode or PWM mode.
Figure 29. Output Compare Block Diagram
16 BIT FREE RUNNING
COUNTER
OC1E OC2E
CC1
CC0
(Control Register 2) CR2
16-bit
(Control Register 1) CR1
OUTPUT COMPARE
CIRCUIT
16-bit
OCIE
FOLV2 FOLV1 OLVL2
OLVL1
16-bit
Latch
1
Latch
2
OC1R Register
OCF1
OCF2
0
0
OCMP1
Pin
OCMP2
Pin
0
OC2R Register
(Status Register) SR
43/109
ST7263
16-BIT TIMER (Cont’d)
Figure 30. Output Compare Timing Diagram, fTIMER =fCPU/2
INTERNAL CPU CLOCK
TIMER CLOCK
COUNTER REGISTER
2ECF 2ED0
2ED1 2ED2 2ED3 2ED4
OUTPUT COMPARE REGISTER i (OCRi)
2ED3
OUTPUT COMPARE FLAG i (OCFi)
OCMPi PIN (OLVLi=1)
Figure 31. Output Compare Timing Diagram, fTIMER =fCPU/4
INTERNAL CPU CLOCK
TIMER CLOCK
COUNTER REGISTER
OUTPUT COMPARE REGISTER i (OCRi)
COMPARE REGISTER i LATCH
OUTPUT COMPARE FLAG i (OCFi)
OCMPi PIN (OLVLi=1)
44/109
2ECF 2ED0
2ED1 2ED2 2ED3 2ED4
2ED3
ST7263
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 applied to the OCMP1 pin after the pulse.
– Using the OLVL2 bit, select the level to be applied to the OCMP1 pin during the pulse.
– Select the edge of the active transition on the
ICAP1 pin with the IEDG1 bit (the ICAP1 pin
must be configured as floating input).
3. Select the following in the CR2 register:
– Set the OC1E bit, the OCMP1 pin is then dedicated to the Output Compare 1 function.
– Set the OPM bit.
– Select the timer clock CC[1:0] (see Table 1).
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, the ICF1 bit is set and
the value FFFDh is loaded in the IC1R register.
Because the ICF1 bit is set when an active edge
occurs, an interrupt can be generated if the ICIE
bit is set.
Clearing the Input Capture interrupt request (i.e.
clearing the ICFi bit) is done in two steps:
1. Reading the SR register while the ICFi bit is set.
2. An access (read or write) to the ICiLR register.
The OC1R register value required for a specific
timing application can be calculated using the following formula:
OCiR Value =
t * fCPU
-5
PRESC
Where:
t
= Pulse period (in seconds)
fCPU = CPU clock frequency (in hertz)
PRESC = Timer prescaler factor (2, 4 or 8 depending on the CC[1:0] bits, see Table 1)
If the timer clock is an external clock the formula is:
OCiR = t * fEXT -5
Where:
t
= Pulse period (in seconds)
fEXT
= External timer clock frequency (in hertz)
When the value of the counter is equal to the value
of the contents of the OC1R register, the OLVL1
bit is output on the OCMP1 pin (see Figure 10).
Notes:
1. The OCF1 bit cannot be set by hardware in
One Pulse mode but the OCF2 bit can generate
an Output Compare interrupt.
2. When the Pulse Width Modulation (PWM) and
One Pulse mode (OPM) bits are both set, the
PWM mode is the only active one.
3. If OLVL1=OLVL2 a continuous signal will be
seen on the OCMP1 pin.
4. The ICAP1 pin can not be used to perform input
capture. The ICAP2 pin can be used to perform
input capture (ICF2 can be set and IC2R can be
loaded) but the user must take care that the
counter is reset each time a valid edge occurs
on the ICAP1 pin and ICF1 can also generates
interrupt if ICIE is set.
5. When One Pulse mode is used OC1R is dedicated to this mode. Nevertheless OC2R and
OCF2 can be used to indicate 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
FFFC FFFD FFFE
2ED0 2ED1 2ED2
FFFC FFFD
2ED3
ICAP1
OLVL2
OCMP1
OLVL1
OLVL2
compare1
Note: IEDG1=1, OC1R=2ED0h, OLVL1=0, OLVL2=1
Figure 33. Pulse Width Modulation Mode Timing Example
COUNTER 34E2 FFFC FFFD FFFE
2ED0 2ED1 2ED2
OLVL2
OCMP1
compare2
OLVL1
compare1
Note: OC1R=2ED0h, OC2R=34E2, OLVL1=0, OLVL2= 1
46/109
34E2
FFFC
OLVL2
compare2
ST7263
16-BIT TIMER (Cont’d)
5.4.3.6 Pulse Width Modulation Mode
Pulse Width Modulation (PWM) mode enables the
generation of a signal with a frequency and pulse
length determined by the value of the OC1R and
OC2R registers.
The Pulse Width Modulation mode uses the complete Output Compare 1 function 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 pulse if OLVL1=0
and OLVL2=1, using the formula in the opposite column.
3. Select the following in the CR1 register:
– Using the OLVL1 bit, select the level to be applied to the OCMP1 pin after a successful
comparison with OC1R register.
– Using the OLVL2 bit, select the level to be applied 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 dedicated to the output compare 1 function.
– Set the PWM bit.
– Select the timer clock (CC[1:0]) (see Table 1).
If OLVL1=1 and OLVL2=0, the length of the positive pulse is the difference between the OC2R and
OC1R registers.
If OLVL1=OLVL2 a continuous signal will be seen
on the OCMP1 pin.
Pulse Width Modulation cycle
When
Counter
= OC1R
When
Counter
= OC2R
OCMP1 = OLVL1
The OCiR register value required for a specific timing application can be calculated using the following formula:
OCiR Value =
t * fCPU
-5
PRESC
Where:
t
= Signal or pulse period (in seconds)
fCPU = CPU clock frequency (in hertz)
PRESC = Timer prescaler factor (2, 4 or 8 depending on CC[1:0] bits, see Table 1)
If the timer clock is an external clock the formula is:
OCiR = t * fEXT -5
Where:
t
= Signal or pulse period (in seconds)
fEXT
= External timer clock frequency (in hertz)
The Output Compare 2 event causes the counter
to be initialized to FFFCh (See Figure 11)
Notes:
1. After a write instruction to the OCiHR register,
the output compare function is inhibited until the
OCiLR register is also written.
2. The OCF1 and OCF2 bits cannot be set by
hardware in PWM mode, therefore the Output
Compare interrupt is inhibited.
3. The ICF1 bit is set by hardware when the counter reaches the OC2R value and can produce a
timer interrupt if the ICIE bit is set and the I bit is
cleared.
4. In PWM mode the ICAP1 pin can not be used
to perform input capture because it is disconnected 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 generate an interrupt
if ICIE is set.
5. When the Pulse Width Modulation (PWM) and
One Pulse mode (OPM) bits are both set, the
PWM mode is the only active one.
OCMP1 = OLVL2
Counter is reset
to FFFCh
ICF1 bit is set
47/109
ST7263
16-BIT TIMER (Cont’d)
5.4.4 Low Power Modes
Mode
WAIT
HALT
Description
No effect on 16-bit Timer.
Timer interrupts cause the device to exit from WAIT mode.
16-bit Timer registers are frozen.
In HALT mode, the counter stops counting until Halt mode is exited. Counting resumes from the previous
count when the MCU is woken up by an interrupt with “exit from HALT mode” capability or from the counter
reset value when the MCU is woken up by a RESET.
If an input capture event occurs on the ICAPi pin, the input capture detection circuitry is armed. Consequently, when the MCU is woken up by an interrupt with “exit from HALT mode” capability, the ICFi bit is set, and
the counter value present when exiting from HALT mode is captured into the ICiR register.
5.4.5 Interrupts
Event
Flag
Interrupt Event
Input Capture 1 event/Counter reset in PWM mode
Input Capture 2 event
Output Compare 1 event (not available in PWM mode)
Output Compare 2 event (not available in PWM mode)
Timer Overflow event
ICF1
ICF2
OCF1
OCF2
TOF
Enable
Control
Bit
ICIE
OCIE
TOIE
Exit
from
Wait
Yes
Yes
Yes
Yes
Yes
Exit
from
Halt
No
No
No
No
No
Note: The 16-bit Timer interrupt events are connected to the same interrupt vector (see Interrupts chapter). These events generate an interrupt if the corresponding Enable Control Bit is set and the interrupt
mask in the CC register is reset (RIM instruction).
5.4.6 Summary of Timer modes
MODES
Input Capture (1 and/or 2)
Output Compare (1 and/or 2)
One Pulse mode
PWM Mode
1)
Input Capture 1
Yes
Yes
No
No
AVAILABLE RESOURCES
Input Capture 2
Output Compare 1 Output Compare 2
Yes
Yes
Yes
Yes
Yes
Yes
1)
No
Partially 2)
Not Recommended
3)
Not Recommended
No
No
See note 4 in Section 0.1.3.5 One Pulse Mode
See note 5 in Section 0.1.3.5 One Pulse Mode
3)
See note 4 in Section 0.1.3.6 Pulse Width Modulation Mode
2)
48/109
ST7263
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 counter and the alternate counter.
CONTROL REGISTER 1 (CR1)
Read/Write
Reset Value: 0000 0000 (00h)
7
0
Bit 4 = FOLV2 Forced Output Compare 2.
This bit is set and cleared by software.
0: No effect on the OCMP2 pin.
1: Forces the OLVL2 bit to be copied to the
OCMP2 pin, if the OC2E bit is set and even if
there is no successful comparison.
Bit 3 = FOLV1 Forced Output Compare 1.
This bit is set and cleared by software.
0: No effect on the OCMP1 pin.
1: Forces OLVL1 to be copied to the OCMP1 pin, if
the OC1E bit is set and even if there is no successful comparison.
ICIE OCIE TOIE FOLV2 FOLV1 OLVL2 IEDG1 OLVL1
Bit 7 = ICIE Input Capture Interrupt Enable.
0: Interrupt is inhibited.
1: A timer interrupt is generated whenever the
ICF1 or ICF2 bit of the SR register is set.
Bit 6 = OCIE Output Compare Interrupt Enable.
0: Interrupt is inhibited.
1: A timer interrupt is generated whenever the
OCF1 or OCF2 bit of the SR register is set.
Bit 5 = TOIE Timer Overflow Interrupt Enable.
0: Interrupt is inhibited.
1: A timer interrupt is enabled whenever the TOF
bit of the SR register is set.
Bit 2 = OLVL2 Output Level 2.
This bit is copied to the OCMP2 pin whenever a
successful comparison occurs with the OC2R register and OCxE is set in the CR2 register. This value is copied to the OCMP1 pin in One Pulse mode
and Pulse Width Modulation mode.
Bit 1 = IEDG1 Input Edge 1.
This bit determines which type of level transition
on the ICAP1 pin will trigger the capture.
0: A falling edge triggers the capture.
1: A rising edge triggers the capture.
Bit 0 = OLVL1 Output Level 1.
The OLVL1 bit is copied to the OCMP1 pin whenever a successful comparison occurs with the
OC1R register and the OC1E bit is set in the CR2
register.
49/109
ST7263
16-BIT TIMER (Cont’d)
CONTROL REGISTER 2 (CR2)
Read/Write
Reset Value: 0000 0000 (00h)
7
0
OC1E OC2E OPM PWM CC1 CC0 IEDG2 EXEDG
Bit 7 = OC1E Output Compare 1 Pin Enable.
This bit is used only to output the signal from the
timer on the OCMP1 pin (OLV1 in Output Compare mode, both OLV1 and OLV2 in PWM and
one-pulse mode). Whatever the value of the OC1E
bit, the internal Output Compare 1 function of the
timer remains active.
0: OCMP1 pin alternate function disabled (I/O pin
free for general-purpose I/O).
1: OCMP1 pin alternate function enabled.
Bit 6 = OC2E Output Compare 2 Pin Enable.
This bit is used only to output the signal from the
timer on the OCMP2 pin (OLV2 in Output Compare mode). Whatever the value of the OC2E bit,
the internal Output Compare 2 function of the timer
remains active.
0: OCMP2 pin alternate function disabled (I/O pin
free for general-purpose I/O).
1: OCMP2 pin alternate function enabled.
Bit 5 = OPM One Pulse mode.
0: One Pulse mode is not active.
1: One Pulse mode is active, the ICAP1 pin can be
used to trigger one pulse on the OCMP1 pin; the
active transition is given by the IEDG1 bit. The
length of the generated pulse depends on the
contents of the OC1R register.
50/109
Bit 4 = PWM Pulse Width Modulation.
0: PWM mode is not active.
1: PWM mode is active, the OCMP1 pin outputs a
programmable cyclic signal; the length of the
pulse depends on the value of OC1R register;
the period depends on the value of OC2R register.
Bits 3:2 = CC[1:0] Clock Control.
The timer clock mode depends on these bits:
Table 16. Clock Control Bits
Timer Clock
fCPU / 4
fCPU / 2
fCPU / 8
External Clock (where
available)
CC1
0
0
1
CC0
0
1
0
1
1
Note: If the external clock pin is not available, programming the external clock configuration stops
the counter.
Bit 1 = IEDG2 Input Edge 2.
This bit determines which type of level transition
on the ICAP2 pin will trigger the capture.
0: A falling edge triggers the capture.
1: A rising edge triggers the capture.
Bit 0 = EXEDG External Clock Edge.
This bit determines which type of level transition
on the external clock pin (EXTCLK) will trigger the
counter register.
0: A falling edge triggers the counter register.
1: A rising edge triggers the counter register.
ST7263
16-BIT TIMER (Cont’d)
STATUS REGISTER (SR)
Read Only
Reset Value: 0000 0000 (00h)
The three least significant bits are not used.
7
ICF1
0
OCF1
TOF
ICF2
OCF2
0
0
0
Bit 7 = ICF1 Input Capture Flag 1.
0: No input capture (reset value).
1: An input capture has occurred on the ICAP1 pin
or the counter has reached the OC2R value in
PWM mode. To clear this bit, first read the SR
register, then read or write the low byte of the
IC1R (IC1LR) register.
Bit 6 = OCF1 Output Compare Flag 1.
0: No match (reset value).
1: The content of the free running counter matches
the content of the OC1R register. To clear this
bit, first read the SR register, then read or write
the low byte of the OC1R (OC1LR) register.
Bit 5 = TOF Timer Overflow Flag.
0: No timer overflow (reset value).
1: The free running counter has rolled over from
FFFFh to 0000h. To clear this bit, first read the
SR register, then read or write the low byte of
the CR (CLR) register.
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 register. To clear this
bit, first read the SR register, then read or write
the low byte of the OC2R (OC2LR) register.
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).
7
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).
7
0
MSB
LSB
OUTPUT COMPARE 1 HIGH REGISTER
(OC1HR)
Read/Write
Reset Value: 1000 0000 (80h)
This is an 8-bit register that contains the high part
of the value to be compared to the CHR register.
7
0
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.
7
0
MSB
LSB
Bit 2-0 = Reserved, forced by hardware to 0.
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 contains the high part
of the value to be compared to the CHR register.
ALTERNATE COUNTER HIGH REGISTER
(ACHR)
Read Only
Reset Value: 1111 1111 (FFh)
This is an 8-bit register that contains the high part
of the counter value.
7
0
7
0
MSB
LSB
MSB
LSB
OUTPUT COMPARE 2 LOW REGISTER
(OC2LR)
Read/Write
Reset Value: 0000 0000 (00h)
This is an 8-bit register that contains the low part of
the value to be compared to the CLR register.
7
0
MSB
LSB
COUNTER HIGH REGISTER (CHR)
Read Only
Reset Value: 1111 1111 (FFh)
This is an 8-bit register that contains the high part
of the counter value.
7
0
MSB
LSB
COUNTER LOW REGISTER (CLR)
Read Only
Reset Value: 1111 1100 (FCh)
This is an 8-bit register that contains the low part of
the counter value. A write to this register resets the
counter. An access to this register after accessing
the SR register clears the TOF bit.
7
0
MSB
LSB
52/109
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 not clear the TOF bit in SR
register.
7
0
MSB
LSB
INPUT CAPTURE 2 HIGH REGISTER (IC2HR)
Read Only
Reset Value: Undefined
This is an 8-bit read only register that contains the
high part of the counter value (transferred by the
Input Capture 2 event).
7
0
MSB
LSB
INPUT CAPTURE 2 LOW REGISTER (IC2LR)
Read Only
Reset Value: Undefined
This is an 8-bit read only register that contains the
low part of the counter value (transferred by the Input Capture 2 event).
7
0
MSB
LSB
ST7263
16-BIT TIMER (Cont’d)
Table 17. 16-Bit Timer Register Map and Reset Values
Address
(Hex.)
11
12
13
14
15
16
17
18
19
1A
1B
1C
1D
1E
1F
Register
Label
7
6
5
4
3
2
1
0
OC1E
OC2E
OPM
PWM
CC1
CC0
IEDG2
EXEDG
Reset Value
CR1
0
ICIE
0
OCIE
0
TOIE
0
FOLV2
0
FOLV1
0
OLVL2
0
IEDG1
0
OLVL1
Reset Value
SR
0
ICF1
0
OCF1
0
TOF
0
ICF2
0
OCF2
0
0
0
0
0
0
Reset Value
IC1HR
0
0
0
0
0
0
0
0
CR2
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
MSB
LSB
MSB
LSB
MSB
1
0
0
0
0
0
0
LSB
0
MSB
0
0
0
0
0
0
0
LSB
0
MSB
1
1
1
1
1
1
1
LSB
1
MSB
1
1
1
1
1
1
0
LSB
0
MSB
1
1
1
1
1
1
1
LSB
1
MSB
1
1
1
1
1
1
0
LSB
0
MSB
LSB
MSB
LSB
MSB
1
0
0
0
0
0
0
LSB
0
MSB
0
0
0
0
0
0
0
LSB
0
53/109
ST7263
5.5 SERIAL COMMUNICATIONS INTERFACE (SCI)
5.5.1 Introduction
5.5.3 General Description
The Serial Communications Interface (SCI) offers
a flexible means of full-duplex data exchange with
external equipment requiring an industry standard
NRZ asynchronous serial data format.
The interface is externally connected to another
device by two pins (see Figure 1):
– TDO: Transmit Data Output. When the transmitter 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.
5.5.2 Main Features
■
■
■
■
■
■
■
■
■
■
Full duplex, asynchronous communications
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
54/109
ST7263
SERIAL COMMUNICATIONS INTERFACE (Cont’d)
Figure 34. SCI Block Diagram
Write
Read
(Data Register) DR
Received Data Register (RDR)
Transmit Data Register (TDR)
TDO
Received Shift Register
Transmit Shift Register
RDI
CR1
R8
WAKE
UP
UNIT
TRANSMIT
CONTROL
T8
-
M
WAKE
-
-
-
RECEIVER
CLOCK
RECEIVER
CONTROL
SR
CR2
TIE TCIE RIE
ILIE
TE
RE RWU SBK
TDRE TC RDRF IDLE OR
NF
FE
-
SCI
INTERRUPT
CONTROL
TRANSMITTER
CLOCK
fCPU
Transmitter Rate
Control
/2
/16
/PR
BRR
SCP1 SCP0 SCT2 SCT1 SCT0 SCR2 SCR1SCR0
Receiver Rate
Control
BAUD RATE GENERATOR
55/109
ST7263
SERIAL COMMUNICATIONS INTERFACE (Cont’d)
5.5.4 Functional Description
The block diagram of the Serial 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
The TDO pin is in low state during the start bit.
The TDO pin is in high state during the stop bit.
An Idle character is interpreted as an entire frame
of “1”s followed by the start bit of the next frame
which contains data.
A Break character is interpreted on receiving “0”s
for some multiple of the frame period. At the end of
the last break frame the transmitter inserts an extra “1” bit to acknowledge the start bit.
Transmission and reception are driven by their
own baud rate generator.
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
9-bit Word length (M bit is set)
Possible
Parity
Bit
Data Frame
Start
Bit
Bit0
Bit2
Bit1
Bit3
Bit4
Bit5
Bit6
Start
Bit
Break Frame
Extra
’1’
Possible
Parity
Bit
Data Frame
56/109
Bit0
Bit8
Next
Stop Start
Bit
Bit
Idle Frame
8-bit Word length (M bit is reset)
Start
Bit
Bit7
Next Data Frame
Bit1
Bit2
Bit3
Bit4
Bit5
Bit6
Bit7
Start
Bit
Next Data Frame
Stop
Bit
Next
Start
Bit
Idle Frame
Start
Bit
Break Frame
Extra Start
Bit
’1’
ST7263
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. When the M
bit is set, word length is 9 bits and the 9th bit (the
MSB) has to be stored in the T8 bit in the CR1 register.
Character Transmission
During an SCI transmission, data shifts out least
significant bit first on the TDO pin. In this mode,
the DR register consists of a buffer (TDR) between
the internal bus and the transmit shift register (see
Figure 1).
Procedure
– Select the M bit to define the word length.
– Select the desired baud rate using the BRR register.
– Set the TE bit to assign the TDO pin to the alternate function and to send a idle frame as first
transmission.
– Access 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 data 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 taking 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.
When a frame transmission is complete (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 TDO 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 to send an idle
frame before the first data frame.
Clearing and then setting the TE bit during a transmission sends an idle frame after the current word.
Note: Resetting and setting the TE bit causes the
data in the TDR register to be lost. Therefore the
best time to toggle the TE bit is when the TDRE bit
is set, i.e. before writing the next byte in the DR.
57/109
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 is 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
– Select the M bit to define the word length.
– Select the desired baud rate using the BRR register.
– 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 reception.
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 the
reception of the next character to avoid an overrun
error.
Break Character
When a break character is received, the SCI handles it as a framing error.
Idle Character
When a idle frame is detected, there is the same
procedure as a data received character plus an interrupt if the ILIE bit is set and the I bit is cleared in
the CC register.
58/109
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 valid incoming data
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 Error
A framing error is detected when:
– The stop bit is not recognized on reception at the
expected time, following either a de-synchronization or excessive noise.
– A break is received.
When the framing error is detected:
– The FE bit is set by hardware
– Data is transferred from the Shift register to the
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.
ST7263
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 independently and calculated as
follows:
Tx =
fCPU
(32*PR)*TR
Rx =
fCPU
(32*PR)*RR
with:
PR = 1, 3, 4 or 13 (see SCP0 & SCP1 bits)
TR = 1, 2, 4, 8, 16, 32, 64,128
(see SCT0, SCT1 & SCT2 bits)
RR = 1, 2, 4, 8, 16, 32, 64,128
(see SCR0,SCR1 & SCR2 bits)
All these bits are in the BRR register.
Example: If fCPU is 8 MHz and if PR=13 and
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
should actively receive the full message contents,
thus reducing redundant SCI service overhead for
all non addressed receivers.
The non addressed devices may be placed in
sleep mode by means of the muting function.
Setting the RWU bit by software puts the SCI in
sleep mode:
All the reception status bits can not be set.
All the receive 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 message is
an address. The reception of this particular word
wakes up the receiver, resets the RWU bit and
sets the RDRF bit, which allows the receiver to receive this word normally and to use it as an address word.
59/109
ST7263
SERIAL COMMUNICATIONS INTERFACE (Cont’d)
5.5.5 Low Power Modes
Mode
WAIT
HALT
Description
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.
5.5.6 Interrupts
Interrupt Event
Transmit Data Register Empty
Transmission Complete
Received Data Ready to be Read
Overrrun Error Detected
Idle Line Detected
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-
60/109
Enable
Control
Bit
TDRE
TIE
TC
TCIE
RDRF
RIE
OR
IDLE
ILIE
Event
Flag
Exit
from
Wait
Yes
Yes
Yes
Yes
Yes
Exit
from
Halt
No
No
No
No
No
rupt mask in the CC register is reset (RIM instruction).
ST7263
SERIAL COMMUNICATIONS INTERFACE (Cont’d)
Note: The IDLE bit will not be set again until 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.
5.5.7 Register Description
STATUS REGISTER (SR)
Read Only
Reset Value: 1100 0000 (C0h)
7
TDRE
0
TC
RDRF
IDLE
OR
NF
FE
0
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
(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.
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 generated 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
1: Transmission is complete
Bit 5 = RDRF 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 4 = IDLE Idle line detect.
This bit is set by hardware when an Idle Line is detected. An interrupt is generated if ILIE=1 in the
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).
0: No Idle Line is detected
1: Idle Line is detected
Bit 3 = OR Overrun error.
This bit is set by hardware when the word currently
being received in the shift register is ready to be
transferred into the RDR register while RDRF=1.
An interrupt is generated if RIE=1 in the 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).
0: No Overrun error
1: Overrun error is detected
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
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.
Bit 1 = FE Framing error.
This bit is set by hardware when a de-synchronization, excessive noise or a break 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 itself generates an interrupt. If the word currently
being transferred causes both frame error and
overrun error, it will be transferred and only the OR
bit will be set.
Bit 0 = Reserved, forced by hardware to 0.
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ST7263
SERIAL COMMUNICATIONS INTERFACE (Cont’d)
0: interrupt is inhibited
CONTROL REGISTER 1 (CR1)
1: An SCI interrupt is generated whenever TC=1 in
Read/Write
the SR register
Reset Value: Undefined
7
R8
0
T8
0
M
WAKE
0
0
0
Bit 7 = R8 Receive data bit 8.
This bit is used to store the 9th bit of the received
word when M=1.
Bit 6 = T8 Transmit data bit 8.
This bit is used to store the 9th bit of the transmitted word when M=1.
Bit 5 = Reserved, forced by hardware to 0.
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
Bit 3 = WAKE Wake-Up method.
This bit determines the SCI Wake-Up method, it is
set or cleared by software.
0: Idle Line
1: Address Mark
Bits 2:0 = Reserved, forced by hardware to 0.
CONTROL REGISTER 2 (CR2)
Read/Write
Reset Value: 0000 0000 (00 h)
7
TIE
0
TCIE
RIE
ILIE
TE
RE
RWU
Bit 4 = ILIE Idle line interrupt enable.
This bit is set and cleared by software.
0: interrupt is inhibited
1: An SCI interrupt is generated whenever IDLE=1
in the SR register.
Bit 3 = TE Transmitter enable.
This bit enables the transmitter and assigns the
TDO pin to the alternate function. It is set and
cleared by software.
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 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.
1: Receiver is enabled and begins searching for a
start bit.
Bit 1 = RWU Receiver wake-up.
This bit determines if the SCI is in mute mode or
not. It is set and cleared by software and can be
cleared by hardware when a wake-up sequence is
recognized.
0: Receiver in active mode
1: Receiver in mute mode
SBK
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 6 = TCIE Transmission complete interrupt enable
This bit is set and cleared by software.
62/109
Bit 5 = RIE Receiver interrupt enable .
This bit is set and cleared by software.
0: interrupt is inhibited
1: An SCI interrupt is generated whenever OR=1
or RDRF=1 in the SR register
Bit 0 = SBK Send break.
This bit set is used to send 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
the current word.
ST7263
SERIAL COMMUNICATIONS INTERFACE (Cont’d)
DATA REGISTER (DR)
Read/Write
Reset Value: Undefined
Contains the Received or Transmitted data character, depending on whether it is read from or written to.
7
0
DR7
DR6
DR5
DR4
DR3
DR2
DR1
DR0
The Data register performs a double function (read
and write) since it is composed of two registers,
one for transmission (TDR) and one for reception
(RDR).
The TDR register provides the parallel interface
between the internal bus and the output shift register (see Figure 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)
7
0
SCP1
SCP0
SCT2
SCT1
SCT0
SCR2
SCR1 SCR0
Bits 7:6= SCP[1:0] First SCI Prescaler
These 2 prescaling bits allow several standard
clock division ranges:
PR Prescaling Factor
SCP1
SCP0
1
0
0
3
0
1
4
1
0
13
1
1
Bits 5:3 = SCT[2:0] SCI Transmitter rate divisor
These 3 bits, in conjunction with the SCP1 & SCP0
bits, define the total division applied to the bus
clock to yield the transmit rate clock in conventional Baud Rate Generator mode.
TR Dividing Factor
SCT2
SCT1
SCT0
1
0
0
0
2
0
0
1
4
0
1
0
8
0
1
1
16
1
0
0
32
1
0
1
64
1
1
0
128
1
1
1
Bits 2:0 = SCR[2:0] SCI Receiver rate divisor.
These 3 bits, in conjunction with the 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
0
0
0
2
0
0
1
4
0
1
0
8
0
1
1
16
1
0
0
32
1
0
1
64
1
1
0
128
1
1
1
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ST7263
SERIAL COMMUNICATIONS INTERFACE (Cont’d)
Table 18. SCI Register Map and Reset Values
Address
(Hex.)
Register
Label
7
6
5
4
3
2
1
0
20
SR
Reset Value
TDRE
1
TC
1
RDRF
0
IDLE
0
OR
0
NF
0
FE
0
0
0
21
DR
Reset Value
DR7
x
DR6
x
DR5
x
DR4
x
DR3
x
DR2
x
DR1
x
DR0
x
22
BRR
Reset Value
SCP1
0
SCP0
0
SCT2
x
SCT1
x
SCT0
x
SCR2
x
SCR1
x
SCR0
x
23
CR1
Reset Value
R8
x
T8
x
0
0
M
x
WAKE
x
0
0
0
0
0
0
24
CR2
Reset Value
TIE
0
TCIE
0
RIE
0
ILIE
0
TE
0
RE
0
RWU
0
SBK
0
64/109
ST7263
5.6 USB INTERFACE (USB)
5.6.1 Introduction
The USB Interface implements a low-speed function interface between the USB and the ST7 microcontroller. It is a highly integrated circuit which
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 (including 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 Figure 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 performs 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 Status register, application software can know which USB event has occurred.
Figure 36. USB Block Diagram
6 MHz
ENDPOINT
REGISTERS
USBDM
Transceiver
SIE
DMA
USBDP
CPU
Address,
data buses
and interrupts
USBVCC
3.3V
Voltage
Regulator
INTERRUPT
REGISTERS
MEMORY
USBGND
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ST7263
USB INTERFACE (Cont’d)
5.6.4 Register Description
DMA ADDRESS REGISTER (DMAR)
Read / Write
Reset Value: Undefined
INTERRUPT/DMA REGISTER (IDR)
Read / Write
Reset Value: xxxx 0000 (x0h)
7
7
DA7
DA15
0
0
DA14
DA13
DA12
DA11
DA10
DA9
DA6
EP1
EP0
CNT3
CNT2
CNT1
CNT0
DA8
Bits 7:0=DA[15:8] DMA address bits 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 IDR
register and Figure 2.
Bits 7:6 = DA[7:6] DMA address bits 7-6.
Software must reset these bits. See the description of the DMAR register and Figure 2.
Bits 5:4 = EP[1:0] Endpoint number (read-only).
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.
Bits 3:0 = CNT[3:0] Byte count (read only).
This field shows how many data bytes have been
received during the last data reception.
Note: Not valid for data transmission.
Figure 37. DMA Buffers
101111
Endpoint 2 TX
101000
100111
Endpoint 2 RX
100000
011111
011000
010111
010000
001111
Endpoint 1 TX
Endpoint 1 RX
Endpoint 0 TX
001000
000111
Endpoint 0 RX
DA15-6,000000
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000000
ST7263
USB INTERFACE (Cont’d)
PID REGISTER (PIDR)
Read only
Reset Value: xx00 0000 (x0h)
INTERRUPT STATUS REGISTER (ISTR)
Read / Write
Reset Value: 0000 0000 (00h)
7
TP3
0
TP2
0
0
0
RX_
SEZ
RXD
0
Bits 7:6 = TP[3:2] Token PID bits 3 & 2.
USB token PIDs are encoded in four bits. TP[3:2]
correspond to the variable token PID bits 3 & 2.
Note: PID bits 1 & 0 have a fixed value of 01.
When a CTR interrupt occurs (see register ISTR)
the software should read the TP3 and TP2 bits to
retrieve the PID name of the token received.
The USB standard defines TP bits as:
TP3
0
1
1
TP2
0
0
1
PID Name
OUT
IN
SETUP
7
SUSP
0
DOVR
CTR
ERR
IOVR
ESUSP
RESET
SOF
When an interrupt occurs these bits are set by
hardware. Software must read them to determine
the interrupt type and clear them after servicing.
Note: These bits cannot be set by software.
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 mode request from the USB
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.
Bit 2 = RX_SEZ Received single-ended zero
This bit indicates the status of the RX_SEZ transceiver output.
0: No SE0 (single-ended zero) state
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 can 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 0 = Reserved. Forced by hardware to 0.
Bit 6 = DOVR DMA over/underrun.
This bit is set by hardware if the ST7 processor
can’t answer a DMA request in time.
0: No over/underrun detected
1: Over/underrun detected
Bit 5 = CTR Correct Transfer. This bit is set by
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 NAK or
STALL handshake is considered not correct (the
host only sends ACK handshakes). A transfer is
considered correct if there are no errors in the PID
and CRC fields, if the DATA0/DATA1 PID is sent
as expected, if there were no data overruns, bit
stuffing or framing errors.
Bit 4 = ERR Error.
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 Interrupt overrun.
This bit is set when hardware tries to set ERR, or
SOF before they have been cleared by software.
0: No overrun detected
1: Overrun detected
Bit 2 = ESUSP End suspend mode.
This bit is set by hardware when, during suspend
mode, activity is detected that wakes the USB interface 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
Bit 1 = RESET 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 on 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)
7
SUS
PM
0
DOV
RM
CTR
M
ERR
M
IOVR
M
ESU
SPM
RES
ETM
SOF
M
Bits 7:0 = These bits are mask bits for all 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
interrupt request is generated. For an explanation
68/109
of each bit, please refer to the corresponding bit
description in ISTR.
CONTROL REGISTER (CTLR)
Read / Write
Reset Value: 0000 0110 (06h)
7
0
0
0
0
0
RESUME
PDWN
FSUSP
FRES
Bits 7:4 = Reserved. Forced by hardware to 0.
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 least 3 µs for stabilisation 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 allowing at least
600 ns before issuing the HALT instruction.
0: Suspend mode inactive
1: Suspend mode active
When the hardware detects USB activity, it resets
this bit (it can also be reset by software).
Bit 0 = FRES Force reset.
This bit is set by software to force a reset of the
USB interface, just as if a RESET sequence came
from the USB.
0: Reset not forced
1: USB interface reset forced.
The USB is held in RESET state until software
clears this bit, at which point a “USB-RESET” interrupt will be generated if enabled.
ST7263
USB INTERFACE (Cont’d)
DEVICE ADDRESS REGISTER (DADDR)
Read / Write
Reset Value: 0000 0000 (00h)
7
0
0
ADD6
ADD5
ADD4
ADD3
ADD2
ADD1
ADD0
Bit 7 = Reserved. Forced by hardware to 0.
Bits 6:0 = ADD[6:0] Device address, 7 bits.
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)
7
ST_
OUT
0
DTOG
_TX
STAT
_TX1
STAT
_TX0
TBC
3
TBC
2
TBC
1
TBC
0
Bit 6 = DTOG_TX Data Toggle, for transmission
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 PID. DTOG_TX toggles only
when the transmitter has received the ACK signal
from the USB host. DTOG_TX and also
DTOG_RX (see EPnRB) are normally updated by
hardware, at the receipt of a relevant PID. They
can be also written by software.
Bits 5:4 = STAT_TX[1:0] Status bits, for transmission transfers.
These bits contain the information about the endpoint status, which are listed below:
STAT_TX1 STAT_TX0 Meaning
DISABLED: transmission
0
0
transfers cannot be executed.
STALL: the endpoint is stalled
0
1
and all transmission requests
result in a STALL handshake.
NAK: the endpoint is naked
1
0
and all transmission requests
result in a NAK handshake.
VALID: this endpoint is ena1
1
bled for transmission.
These registers (EP0RA, EP1RA and EP2RA) are
used for controlling data transmission. They are
also reset by the USB bus reset.
Note: Endpoint 2 and the EP2RA register are not
available on some devices (see device feature list
and register map).
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.
Bit 7 = ST_OUT Status out.
This bit is set by software to indicate that a status
out packet is expected: in this case, all nonzero
OUT data transfers on the endpoint are STALLed
instead of being ACKed. When ST_OUT is reset,
OUT transactions can have any number of bytes,
as needed.
Bits 3:0 = TBC[3:0] Transmit byte count for Endpoint n.
Before transmission, after filling the transmit buffer, software must write in the TBC field the transmit packet size expressed in bytes (in the range 08).
69/109
ST7263
USB INTERFACE (Cont’d)
ENDPOINT n REGISTER B (EPnRB)
Read / Write
Reset Value: 0000 xxxx (0xh)
STAT_RX1
7
CTRL
1
0
1
1
NAK: the endpoint is naked and all reception requests result in a NAK
handshake.
VALID: this endpoint is
enabled for reception.
0
DTOG
_RX
STAT
_RX1
STAT
_RX0
EA3
EA2
EA1
EA0
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 and the EP2RB register are not
available on some devices (see device feature list
and register map).
Bit 7 = CTRL Control.
This bit should be 0.
Note: If this bit is 1, the Endpoint is a control endpoint. (Endpoint 0 is always a control Endpoint, but
it is possible to have more than one control Endpoint).
Bit 6 = DTOG_RX Data toggle, for reception transfers .
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 only if it receives a correct
data packet and the packet’s data PID matches
the receiver sequence bit.
Bits 5:4 = STAT_RX [1:0] Status bits, for reception
transfers.
These bits contain the information about the endpoint status, which are listed below:
STAT_RX1
STAT_RX0 Meaning
0
0
0
1
70/109
STAT_RX0 Meaning
DISABLED: reception
transfers cannot be executed.
STALL: the endpoint is
stalled and all reception
requests result in a
STALL handshake.
These bits are written by software. Hardware sets
the STAT_RX bits to NAK when a correct 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)
7
1
0
DTOG
RX
STAT
RX1
STAT
RX0
0
0
0
0
This register is used for controlling data reception
on Endpoint 0. It is also reset by the USB bus reset.
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.
ST7263
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, the software must initialize 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 endpoint 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 to 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 number 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.
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 generated 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 in all endpoint
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 about the lack of bus activity
for more than 3 ms, which is a suspend request.
The software should set the USB interface to suspend mode and execute an ST7 HALT instruction
to meet the USB-specified power constraints.
End Suspend (ESUSP)
The CPU is alerted by activity on the USB, 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 transfer which generated the
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 the IDR
to get the endpoint number related to the last
transfer.
Note: When a CTR interrupt occurs, the TP3TP2 bits in the PIDR register and EP1-EP0 bits
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.
71/109
ST7263
USB INTERFACE (Cont’d)
Table 19. USB Register Map and Reset Values
Address
(Hex.)
25
26
27
28
29
2A
2B
2C
2D
2E
2F
30
31
72/109
Register
Name
7
6
5
4
3
2
1
0
TP3
TP2
0
0
0
RX_SEZ
RXD
0
Reset Value
DMAR
x
DA15
x
DA14
0
DA13
0
DA12
0
DA11
0
DA10
0
DA9
0
DA8
Reset Value
IDR
x
DA7
x
DA6
x
EP1
x
EP0
x
CNT3
x
CNT2
x
CNT1
x
CNT0
Reset Value
ISTR
x
SUSP
x
DOVR
x
CTR
x
ERR
0
IOVR
0
ESUSP
0
RESET
0
SOF
Reset Value
IMR
0
SUSPM
0
DOVRM
0
CTRM
0
ERRM
0
IOVRM
Reset Value
CTLR
0
0
0
0
0
0
0
0
0
RESUME
0
PDWN
0
FSUSP
0
FRES
Reset Value
DADDR
0
0
0
ADD6
0
ADD5
0
ADD4
0
ADD3
1
ADD2
1
ADD1
0
ADD0
Reset Value
EP0RA
0
ST_OUT
0
0
TBC3
0
TBC2
0
TBC1
0
TBC0
Reset Value
EP0RB
0
1
0
0
STAT_TX1
STAT_TX0
DTOG_TX
0
0
0
DTOG_RX STAT_RX1 STAT_RX0
x
0
x
0
x
0
x
0
Reset Value
EP1RA
1
ST_OUT
0
0
0
DTOG_TX STAT_TX1 STAT_TX0
0
TBC3
0
TBC2
0
TBC1
0
TBC0
Reset Value
EP1RB
0
CTRL
0
0
0
DTOG_RX STAT_RX1 STAT_RX0
x
EA3
x
EA2
x
EA1
x
EA0
Reset Value
EP2RA
0
ST_OUT
0
0
0
DTOG_TX STAT_TX1 STAT_TX0
x
TBC3
x
TBC2
x
TBC1
x
TBC0
Reset Value
EP2RB
0
CTRL
0
0
0
DTOG_RX STAT_RX1 STAT_RX0
x
EA3
x
EA2
x
EA1
x
EA0
Reset Value
0
x
x
x
x
PIDR
0
0
0
0
0
ESUSPM RESETM
0
SOFM
ST7263
5.7 I²C BUS INTERFACE (I²C)
5.7.1 Introduction
The I²C Bus Interface serves as an interface between the microcontroller and the serial I²C bus. It
provides both multimaster and slave functions,
and controls all I²C bus-specific sequencing, protocol, arbitration and timing. It supports fast I²C
mode (400 kHz).
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 both with a standard I²C bus
and a Fast I²C bus. This selection is made by software.
Mode Selection
The interface can operate in the four following
modes:
– Slave transmitter/receiver
– Master transmitter/receiver
By default, it operates in slave mode.
The interface automatically switches from slave to
master after it generates a START condition and
from master to slave in case of arbitration loss or a
STOP generation, this allows Multi-Master capability.
Communication Flow
In Master mode, it initiates a data transfer and
generates the clock signal. A serial data transfer
always begins with a start condition and ends with
a stop condition. Both start and stop conditions are
generated in master mode by software.
In Slave mode, the interface is capable of recognising its own address (7-bit), and the General Call
address. The General Call address detection may
be enabled or disabled by software.
Data and addresses are transferred as 8-bit bytes,
MSB first. The first byte following the start condition is the address byte; it is always transmitted in
Master mode.
A 9th clock pulse follows the 8 clock cycles of a
byte transfer, during which the receiver must send
an acknowledge bit to the transmitter. Refer to Figure 1.
Figure 38. I²C BUS Protocol
SDA
ACK
MSB
SCL
1
START
CONDITION
2
8
9
STOP
CONDITION
VR02119B
73/109
ST7263
I²C BUS INTERFACE (Cont’d)
The Acknowledge function may be enabled and
disabled by software.
The I²C interface address and/or general call address can be selected by software.
The speed of the I²C interface may be selected between Standard (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.
The SCL frequency (FSCL) is controlled by a programmable clock divider which depends on the I²C
bus mode.
When the I²C cell is enabled, the SDA and SCL
ports must be configured as floating open-drain
output or floating input. In this case, the value of
the external pull-up resistor used depends on the
application.
When the I²C cell is disabled, the SDA and SCL
ports revert to being standard I/O port pins.
Figure 39. I²C Interface Block Diagram
DATA REGISTER (DR)
SDAI
DATA CONTROL
SDA
DATA SHIFT REGISTER
COMPARATOR
OWN ADDRESS REGISTER (OAR)
SCLI
SCL
CLOCK CONTROL
CLOCK CONTROL REGISTER (CCR)
CONTROL REGISTER (CR)
STATUS REGISTER 1 (SR1)
CONTROL LOGIC
STATUS REGISTER 2 (SR2)
INTERRUPT
74/109
ST7263
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 SDA line and sent to
the shift register; then it is compared with the
address of the interface or the General Call
address (if selected by software).
Address not matched: the interface ignores it
and waits for another Start condition.
Address matched: the interface generates in sequence:
– An Acknowledge pulse is generated if the ACK
bit is set.
– EVF and ADSL bits are set with an interrupt if the
ITE bit is set.
Then the interface waits for a read of the SR1 register, holding the SCL line low (see Figure 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 Acknowledge pulse 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 SCL line low (see Figure 3 Transfer sequencing EV2).
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 transferred a Stop Condition is generated by the master. The interface
detects this condition and sets:
– EVF and STOPF bits with an interrupt if the ITE
bit is set.
Then the interface waits for a read of the SR2 register (see Figure 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/SCL lines are released 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 register to the SDA line via the internal shift
register.
75/109
ST7263
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 SDA
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 the CR register (for example set PE bit), holding the SCL line low (see Figure 3 Transfer sequencing EV6).
Next the master must enter Receiver or Transmitter mode.
Master Receiver
Following the address transmission and after the
SR1 and CR registers have been accessed, the
master receives bytes from the SDA line into the
DR register via the internal shift register. After
each byte the interface generates in sequence:
– An Acknowledge pulse is generated if if the ACK
bit is set
– EVF and BTF bits are set by hardware with an interrupt if the ITE bit is set.
Then the interface waits for a read of the SR1 register followed by a read of the DR register, holding
the SCL line low (see Figure 3 Transfer sequencing EV7).
76/109
To close the communication: before reading the
last byte from the DR register, set the STOP bit to
generate the Stop condition. The interface 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 condition. The interface goes automatically back to slave mode (M/SL bit cleared).
Error Cases
– BERR: Detection of a Stop or a Start condition
during a byte transfer. In this case, the EVF and
BERR bits are set by hardware with an interrupt
if 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 an interrupt if the ITE bit is set. 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.
ST7263
I²C BUS INTERFACE (Cont’d)
Figure 40. Transfer Sequencing
Slave Receiver
S Address
A
Data1
A
EV1
Data2
A
EV2
EV2
.....
DataN
A
P
EV2
EV4
Slave Transmitter
S Address
A
Data1
A
EV1 EV3
Data2
A
EV3
EV3
.....
DataN
NA
P
EV3-1
EV4
Master Receiver
S
Address
A
EV5
Data1
A
EV6
Data2
A
EV7
EV7
.....
DataN
NA
P
EV7
Master Transmitter
S
Address
EV5
A
Data1
EV6 EV8
A
Data2
EV8
A
EV8
.....
DataN
A
P
EV8
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.
77/109
ST7263
I²C BUS INTERFACE (Cont’d)
5.7.5 Low Power Modes
Mode
WAIT
HALT
Description
No effect on I²C interface.
I²C interrupts exit from Wait mode.
I²C registers are frozen.
In Halt mode, the I²C interface is inactive and does not acknowledge data on the bus. The I²C
interface resumes operation when the MCU is woken up by an interrupt with “exit from Halt
mode” capability.
5.7.6 Interrupts
Figure 41. Event Flags and Interrupt Generation
BTF
ADSL
SB
AF
STOPF
ARLO
BERR
ITE
INTERRUPT
EVF
*
* EVF can also be set by EV6 or an error from the SR2 register.
Interrupt Event
End of Byte Transfer Event
Address Matched Event (Slave mode)
Start Bit Generation Event (Master mode)
Acknowledge Failure Event
Stop Detection Event (Slave mode)
Arbitration Lost Event (Multimaster configuration)
Bus Error Event
The I²C interrupt events are connected to the
same interrupt vector (see Interrupts chapter).
78/109
Event
Flag
Enable
Control
Bit
BTF
ADSEL
SB
AF
STOPF
ARLO
BERR
ITE
Exit
from
Wait
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Exit
from
Halt
No
No
No
No
No
No
No
They generate an interrupt if the corresponding
Enable Control Bit is set and the I-bit in the CC
register is reset (RIM instruction).
ST7263
I²C BUS INTERFACE (Cont’d)
5.7.7 Register Description
I²C CONTROL REGISTER (CR)
Read / Write
Reset Value: 0000 0000 (00h)
7
0
0
0
PE
ENGC START
ACK
STOP
ITE
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:
– When PE=0, all the bits of the CR register and
the SR register except the Stop bit are reset. All
outputs are released while PE=0
– When PE=1, the corresponding I/O pins are selected by hardware as alternate functions.
– To enable the I²C interface, write the CR register
TWICE with PE=1 as the first write only activates
the interface (only PE is set).
Bit 4 = ENGC Enable General Call.
This bit is set and cleared by software. It is also
cleared by hardware when the interface is disabled (PE=0). The 00h General Call address is acknowledged (01h ignored).
0: General Call disabled
1: General Call enabled
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 2 = ACK Acknowledge enable.
This bit is set and cleared by software. It is also
cleared by hardware when the interface is disabled (PE=0).
0: No acknowledge returned
1: Acknowledge returned after an address byte or
a data byte is received
Bit 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 ADSL flags
or an EV6 event (See Figure 3) is detected.
79/109
ST7263
I²C BUS INTERFACE (Cont’d)
I²C STATUS REGISTER 1 (SR1)
Read Only
Reset Value: 0000 0000 (00h)
7
EVF
0
0
TRA
BUSY
BTF
ADSL
M/SL
SB
Bit 7 = EVF Event flag.
This bit is set by hardware as soon as an event occurs. It is cleared by software reading SR2 register
in case of error event or as described in Figure 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
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 Master mode.
Bit 6 = Reserved. Forced to 0 by hardware.
Bit 5 = TRA Transmitter/Receiver.
When BTF is set, TRA=1 if a data byte has been
transmitted. It is cleared automatically when BTF
is cleared. It is also cleared by hardware after detection of Stop condition (STOPF=1), loss of bus
arbitration (ARLO=1) or when the interface is disabled (PE=0).
0: Data byte received (if BTF=1)
1: Data byte transmitted
Bit 4 = BUSY Bus busy .
This bit is set by hardware on detection of a Start
condition and cleared by hardware on detection of
a Stop condition. It indicates a communication in
progress on the bus. 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 3 = BTF Byte transfer finished.
This bit is set by hardware as soon as a byte is correctly received or transmitted with interrupt generation if ITE=1. It is cleared by software reading
SR1 register followed by a read or write of DR register. It is also cleared by hardware when the interface is disabled (PE=0).
– Following a byte transmission, this bit is set after
reception of the acknowledge clock pulse. In
case an address byte is sent, this bit is set only
after the EV6 event (See Figure 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
Bit 2 = ADSL Address matched (Slave mode).
This bit is set by hardware as soon as the received
slave address matched with the OAR register content or a general call is recognized. An interrupt is
generated if ITE=1. It is cleared by software reading SR1 register or by hardware when the interface is disabled (PE=0).
The SCL line is held low while ADSL=1.
0: Address mismatched or not received
1: Received address matched
Bit 1 = M/SL Master/Slave.
This bit is set by hardware as soon as the interface
is in Master mode (writing START=1). It is cleared
by hardware after detecting a Stop condition on
the bus or a loss of arbitration (ARLO=1). It is also
cleared when the interface is disabled (PE=0).
0: Slave mode
1: Master mode
Bit 0 = SB Start bit (Master mode).
This bit is set by hardware as soon as the Start
condition is generated (following a write
START=1). An interrupt is generated if ITE=1. It is
cleared by software reading SR1 register followed
by writing the address byte in DR register. It is also
cleared by hardware when the interface is disabled (PE=0).
0: No Start condition
1: Start condition generated
ST7263
I²C BUS INTERFACE (Cont’d)
I²C STATUS REGISTER 2 (SR2)
Read Only
Reset Value: 0000 0000 (00h)
7
0
0
0
0
AF
STOPF ARLO BERR GCAL
Bits 7:5 = Reserved. Forced to 0 by hardware.
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
automatically to Slave mode (M/SL=0).
The SCL line is not held low while ARLO=1.
0: No arbitration lost detected
1: Arbitration lost detected
Bit 4 = AF Acknowledge failure.
This bit is set by hardware when no acknowledge
is returned. An interrupt is generated if ITE=1. It is
cleared by software reading SR2 register or by
hardware when the interface is disabled (PE=0).
The SCL line is not held low while AF=1.
0: No acknowledge failure
1: Acknowledge failure
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 3 = STOPF Stop detection (Slave mode).
This bit is set by hardware when a Stop condition
is detected on the bus after an acknowledge (if
ACK=1). An interrupt is generated if ITE=1. It is
cleared by software reading SR2 register or by
hardware when the interface is disabled (PE=0).
The SCL line is not held low while STOPF=1.
0: No Stop condition detected
1: Stop condition detected
Bit 0 = GCAL General Call (Slave mode).
This bit is set by hardware when a general call address is detected on the bus while ENGC=1. It is
cleared by hardware detecting a Stop condition
(STOPF=1) or when the interface is disabled
(PE=0).
0: No general call address detected on bus
1: general call address detected on bus
Bit 2 = ARLO Arbitration lost.
This bit is set by hardware when the interface los-
81/109
ST7263
I²C BUS INTERFACE (Cont’d)
I²C CLOCK CONTROL REGISTER (CCR)
Read / Write
Reset Value: 0000 0000 (00h)
7
FM/SM
CC6
CC5
CC4
CC3
CC2
CC1
I²C OWN ADDRESS REGISTER (OAR)
Read / Write
Reset Value: 0000 0000 (00h)
0
7
CC0
ADD7
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 7-bit clock divider.
These bits select the speed of the bus (FSCL) depending on the I²C mode. They are not cleared
when the interface is disabled (PE=0).
– Standard mode (FM/SM=0): FSCL <= 100kHz
FSCL = fCPU/(2x([CC6..CC0]+2))
– Fast mode (FM/SM=1): FSCL > 100kHz
FSCL = fCPU/(3x([CC6..CC0]+2))
Note: The programmed FSCL assumes no load on
SCL and SDA lines.
I²C DATA REGISTER (DR)
Read / Write
Reset Value: 0000 0000 (00h)
7
D7
0
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.
– Transmitter mode: Byte transmission start automatically when the software writes in the DR register.
– Receiver mode: the first data byte is received automatically in the DR register using the least significant bit of the address.
Then, the next data bytes are received one by
one after reading the DR register.
82/109
0
ADD6
ADD5
ADD4
ADD3
ADD2
ADD1
ADD0
Bits 7:1 = ADD7-ADD1 Interface address .
These bits define the I²C bus address of the interface. They are not cleared when the interface is
disabled (PE=0).
Bit 0 = ADD0 Address direction bit.
This bit is don’t care, the interface acknowledges
either 0 or 1. It is not cleared when the interface is
disabled (PE=0).
Note: Address 01h is always ignored.
ST7263
Table 20. I2C Register Map
Address
(Hex.)
39
3B
3C
3D
3E
3F
Register
Name
DR
OAR
CCR
SR2
SR1
CR
7
6
5
FM/SM
EVF
TRA
PE
4
3
DR7 .. DR0
ADD7 .. ADD0
CC6 .. CC0
AF
STOPF
BUSY
BTF
ENGC
START
2
1
0
ARLO
ADSL
ACK
BERR
M/SL
STOP
GCAL
SB
ITE
83/109
ST7263
5.8 8-BIT A/D CONVERTER (ADC)
5.8.1 Introduction
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 voltage
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.
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.
Figure 42. ADC Block Diagram
COCO
-
ADON
0
-
CH2
CH1
CH0
(Control Status Register) CSR
AIN0
AIN1
AIN2
AIN3
AIN4
AIN5
AIN6
AIN7
ANALOG
MUX
fCPU
SAMPLE
&
HOLD
ANALOG TO
DIGITAL
CONVERTER
AD7
AD6
AD5
AD4
AD3
AD2
AD1
(Data Register) DR
84/109
AD0
ST7263
8-BIT A/D CONVERTER (ADC) (Cont’d)
5.8.3 Functional Description
The high level reference voltage VDDA must be
connected externally to the V DD pin. The low level
reference voltage V SSA must be connected externally to the VSS pin. In some devices (refer to device pin out description) high and low level reference voltages are internally connected to the VDD
and VSS pins.
Conversion accuracy may therefore be degraded
by voltage drops and noise in the event of heavily
loaded or badly decoupled power supply lines.
Figure 43. Recommended Ext. Connections
VDD
VDDA
0.1µF
VSSA
ST7
RAIN
VAIN
Px.x/AINx
Characteristics:
The conversion is monotonic, meaning the result
never decreases if the analog input does not and
never increases if the analog input does not.
If input voltage is greater than or equal to VDD
(voltage reference high) then results = FFh (full
scale) without overflow indication.
If input voltage ≤ VSS (voltage reference low) then
the results = 00h.
The conversion time is 64 CPU clock cycles including a sampling time of 31.5 CPU clock cycles.
RAIN is the maximum recommended impedance
for an analog input signal. If the impedance is too
high, this will result in a loss of accuracy due to
leakage and sampling not being completed in the
alloted time.
The A/D converter is linear and the digital result of
the conversion is given by the formula:
Digital result =
255 x Input Voltage
Reference Voltage
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 pins as analog inputs does
not affect the ability of the port to be read as a logic
input.
In the CSR register:
– Select the CH2 to CH0 bits to assign the analog channel to convert. Refer to Table 21
Channel Selection.
– Set the ADON bit. Then the A/D converter is
enabled after a stabilization time (typically 30
µs). It then performs a continuous conversion
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 resetting the ADON bit. This feature allows reduced
power consumption when no conversion is needed.
Mode
WAIT
HALT
Description
No effect on A/D Converter
A/D Converter disabled.
After wakeup from Halt mode, the A/D
Converter requires a stabilisation time
before accurate conversions can be
performed.
5.8.5 Interrupts
None.
Where Reference Voltage is VDD - VSS.
85/109
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)
7
COCO
Table 21. Channel Selection
0
-
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.
Bit 6 = Reserved. 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 ADON bit is set.
Bit 4 = Reserved. Forced by hardware to 0.
Bit 3 = Reserved. 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.
86/109
Pin*
CH2
CH1
CH0
AIN0
0
0
0
AIN1
0
0
1
AIN2
0
1
0
AIN3
0
1
1
AIN4
1
0
0
AIN5
1
0
1
AIN6
1
1
0
AIN7
1
1
1
*IMPORTANT NOTE: The number of pins AND
the channel selection vary according to the device.
REFER TO THE DEVICE PINOUT).
DATA REGISTER (DR)
Read Only
Reset Value: 0000 0000 (00h)
7
AD7
0
AD6
AD5
AD4
AD3
AD2
AD1
AD0
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.
ST7263
6 INSTRUCTION SET
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
The ST7 Instruction set is designed to minimize
the number of bytes required per instruction: To do
so, most of the addressing modes may be subdivided in two sub-modes called long and short:
– Long addressing mode is more powerful because it can use the full 64 Kbyte address space,
however it uses more bytes and more CPU cycles.
– Short addressing mode is less powerful because
it can generally only access page zero (0000h 00FFh range), but the instruction size is more
compact, and faster. All memory to memory instructions use short addressing modes only
(CLR, CPL, NEG, BSET, BRES, BTJT, BTJF,
INC, DEC, RLC, RRC, SLL, SRL, SRA, SWAP)
The ST7 Assembler optimizes the use of long and
short addressing modes.
Table 22. ST7 Addressing Mode Overview
Mode
Syntax
Pointer
Address
(Hex.)
Destination/
Source
Pointer
Size
(Hex.)
Length
(Bytes)
Inherent
nop
+0
Immediate
ld A,#$55
+1
Short
Direct
ld A,$10
00..FF
+1
Long
Direct
ld A,$1000
0000..FFFF
+2
No Offset
Direct
Indexed
ld A,(X)
00..FF
+ 0 (with X register)
+ 1 (with Y register)
Short
Direct
Indexed
ld A,($10,X)
00..1FE
+1
Long
Direct
Indexed
Short
Indirect
ld A,($1000,X)
0000..FFFF
ld A,[$10]
00..FF
+2
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
00..FF
byte
00..FF
byte
1)
Relative
Direct
jrne loop
PC-128/PC+127
Relative
Indirect
jrne [$10]
PC-128/PC+1271)
Bit
Direct
bset $10,#7
00..FF
Bit
Indirect
bset [$10],#7
00..FF
Bit
Direct
Relative
btjt $10,#7,skip
00..FF
Bit
Indirect
Relative
btjt [$10],#7,skip 00..FF
+1
+2
+1
+2
+2
00..FF
byte
+3
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
Wait For Interrupt (Low Power
Mode)
HALT
Halt Oscillator (Lowest Power
Mode)
RET
Sub-routine Return
IRET
Interrupt Sub-routine Return
SIM
Set Interrupt Mask
RIM
Reset Interrupt Mask
SCF
Set Carry Flag
RCF
Reset Carry Flag
RSP
Reset Stack Pointer
LD
Load
CLR
Clear
PUSH/POP
Push/Pop to/from the stack
INC/DEC
Increment/Decrement
TNZ
Test Negative or Zero
CPL, NEG
1 or 2 Complement
MUL
Byte Multiplication
SLL, SRL, SRA, RLC,
RRC
Shift and Rotate Operations
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
88/109
6.1.3 Direct
In Direct instructions, the operands are referenced
by their memory address.
The direct addressing mode consists of two submodes:
Direct (short)
The address is a byte, thus requires only one byte
after the opcode, but only allows 00 - FF addressing space.
Direct (long)
The address is a word, thus allowing 64 Kbyte addressing space, but requires 2 bytes after the opcode.
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 bytes 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 the opcode. The indirect 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 (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.
ST7263
ST7 ADDRESSING MODES (Cont’d)
6.1.6 Indirect Indexed (Short, Long)
This is a combination of indirect and short indexed
addressing modes. The operand is referenced by
its memory address, which is defined by the unsigned addition of an index register value (X or Y)
with a pointer value located in memory. The pointer address follows the opcode.
The indirect indexed addressing mode consists of
two 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 Indexed (Long)
The pointer address is a byte, the pointer size is a
word, thus allowing 64 Kbyte addressing space,
and requires 1 byte after the opcode.
Table 23. Instructions Supporting Direct,
Indexed, Indirect and Indirect Indexed
Addressing Modes
Long and Short
Instructions
SWAP
Swap Nibbles
CALL, JP
Call or Jump subroutine
6.1.7 Relative Mode (Direct, Indirect)
This addressing mode is used to modify the PC
register value by adding an 8-bit signed offset to it.
Available Relative Direct/
Indirect Instructions
Function
JRxx
Conditional Jump
CALLR
Call Relative
The relative addressing mode consists of two submodes:
Relative (Direct)
The offset follows the opcode.
Relative (Indirect)
The offset is defined in memory, of which the address follows the opcode.
Function
LD
Load
CP
Compare
AND, OR, XOR
Logical Operations
ADC, ADD, SUB, SBC
Arithmetic Addition/subtraction operations
BCP
Bit Compare
Short Instructions Only
Function
CLR
Clear
INC, DEC
Increment/Decrement
TNZ
Test Negative or Zero
CPL, NEG
1 or 2 Complement
BSET, BRES
Bit Operations
BTJT, BTJF
Bit Test and Jump Operations
SLL, SRL, SRA, RLC,
RRC
Shift and Rotate Operations
89/109
ST7263
6.2 INSTRUCTION GROUPS
The ST7 family devices use an Instruction Set
consisting of 63 instructions. The instructions may
be subdivided into 13 main groups as illustrated in
the following table:
Load and Transfer
LD
CLR
Stack operation
PUSH
POP
Increment/Decrement
INC
DEC
Compare and Tests
CP
TNZ
BCP
Logical operations
AND
OR
XOR
CPL
NEG
Bit Operation
BSET
BRES
Conditional Bit Test and Branch
BTJT
BTJF
Arithmetic operations
ADC
ADD
SUB
SBC
MUL
Shift and Rotates
SLL
SRL
SRA
RLC
RRC
SWAP
SLA
Unconditional Jump or Call
JRA
JRT
JRF
JP
CALL
CALLR
NOP
Conditional Branch
JRxx
Interruption management
TRAP
WFI
HALT
IRET
Code Condition Flag modification
SIM
RIM
SCF
RCF
Using a pre-byte
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 are defined. These prebytes
modify the meaning of the instruction they precede.
The whole instruction becomes:
PC-2 End of previous instruction
PC-1 Prebyte
PC
Opcode
PC+1 Additional word (0 to 2) according to the
number of bytes required to compute the
effective address
90/109
RSP
RET
These prebytes enable instruction in Y as well as
indirect addressing modes to be implemented.
They precede the opcode of the instruction in X or
the instruction using direct addressing mode. The
prebytes are:
PDY 90 Replace an X based instruction using
immediate, direct, indexed, or inherent
addressing mode by a Y one.
PIX 92 Replace an instruction using direct, direct bit, or direct relative addressing
mode to an instruction using the corresponding indirect addressing mode.
It also changes an instruction using X
indexed addressing mode to an instruction using indirect X indexed addressing
mode.
PIY 91 Replace an instruction using X indirect
indexed addressing mode by a Y one.
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
CP
Arithmetic Compare
tst(Reg - M)
reg
reg, M
CPL
One Complement
A = FFH-A
DEC
Decrement
dec Y
HALT
Halt
IRET
Interrupt routine return
Pop CC, A, X, PC
INC
Increment
inc X
JP
Absolute Jump
jp [TBL.w]
JRA
Jump relative always
JRT
Jump relative
JRF
Never jump
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 >
0
1
N
Z
C
reg, M
N
Z
1
reg, M
N
Z
N
Z
N
Z
M
0
H
reg, M
I
C
jrf *
91/109
ST7263
INSTRUCTION GROUPS (Cont’d)
Mnemo
Description
Function/Example
Dst
Src
JRULE
Jump if (C + Z = 1)
Unsigned <=
LD
Load
dst <= src
reg, M
M, reg
MUL
Multiply
X,A = X * A
A, X, Y
X, Y, A
NEG
Negate (2’s compl)
neg $10
reg, M
NOP
No Operation
OR
OR operation
A=A+M
A
M
POP
Pop from the Stack
pop reg
reg
M
pop CC
CC
M
M
reg, CC
H
I
N
Z
N
Z
0
H
C
0
I
N
Z
N
Z
N
Z
C
C
PUSH
Push onto the Stack
push Y
RCF
Reset carry flag
C=0
RET
Subroutine Return
RIM
Enable Interrupts
I=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
N
Z
C
SCF
Set carry flag
C=1
SIM
Disable Interrupts
I=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
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
WFI
Wait for Interrupt
XOR
Exclusive OR
N
Z
92/109
0
0
A
M
1
1
M
1
0
A = A XOR M
A
M
ST7263
7 ELECTRICAL CHARACTERISTICS
7.1 ABSOLUTE MAXIMUM RATINGS
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 those quoted in the Absolute Maximum Ratings. For proper operation, it is
recommended that the input voltage V IN be constrained within the range:
(VSS - 0.3V) ≤ VIN ≤ (VDD + 0.3V)
To enhance reliability of operation, it is recommended to configure unused I/Os as inputs and to
connect them to an appropriate logic voltage level
such as VSS or VDD. it is also recommended to
connect VDDA and VDD together on application.
(same remark for VSSA and VSS).
All the voltage in the following tables are referenced to VSS.
Stresses above those listed as “Absolute Maximum Ratings” may cause permanent damage to
the device. Functional operation of the device at
these conditions is not implied. Exposure to maximum rating conditions for extended periods may
affect device reliability.
Table 24. Absolute Maximum Ratings (Voltage Referenced to VSS )
Symbol
VDD
VDDA
Ratings
Value
Unit
Recommended Supply Voltage
- 0.3 to +6.0
V
Analog Reference Voltage
- 0.3 to +6.0
V
|VDDA - VDD|
Max. variations on Power Line
50
mV
|VSSA - VSS|
Max. variations on Ground Line
50
mV
IVDD - IVSS
VIN
VOUT
Total current into VDD/VSS
Input Voltage
80/80
mA
VSS - 0.3 to VDD + 0.3
V
Output Voltage
VSS - 0.3 to VDD + 0.3
V
TA
Ambient Temperature Range
TSTG
Storage Temperature Range
TL to TH
0 to + 70
°C
-65 to +150
°C
TJ
Junction Temperature
150
°C
PD
Power Dissipation
350
mW
ESD
ESD susceptibility
2000
V
93/109
ST7263
7.2 THERMAL CHARACTERISTICS
The average chip-junction temperature, TJ, in degrees Celsius, may be calculated using the following equation:
An approximate relationship between PD and TJ
(if PI/O is neglected) is given by:
PD = K÷ (TJ + 273°C) (2)
TJ = TA + (PD x θJA) (1)*
Therefore:
Where:
– TA is the Ambient Temperature in °C,
– θJA is the Package Junction-to-Ambient Thermal
Resistance, in °C/W,
– P D is the sum of PINT and P I/O,
– P INT is the product of IDD and VDD, expressed in
Watts. This is the Chip Internal Power
– P I/O represents the Power Dissipation on Input
and Output Pins; User Determined.
For most applications P I/O <PINT and may be neglected. P I/O may be significant if the device is configured to drive Darlington bases or sink LED Loads.
K = PD x (TA + 273°C) + θJA x P D2 (3)
Where:
– K is a constant for the particular part, which may
be determined from equation (3) by measuring
PD (at equilibrium) for a known T A. Using this value of K, the values of PD and TJ may be obtained
by solving equations (1) and (2) iteratively for any
value of TA.
Table 25. Thermal Characteristics
Symbol
θJA
Package
Typical Value
SO34
70
PSDIP32
50
(*): Maximum chip dissipation can directly be obtained from Tj (max), θJA and TA parameters.
94/109
Unit
°C/W
ST7263
7.3 OPERATING CONDITIONS
General Operating Conditions
(TA = 0 to +70°C unless otherwise specified)
Symbol
VDD
fOSC
Parameter
Supply voltage
1)
External clock frequency
Min
Max
Unit
fCPU = 4 MHz ; USB not guaranteed
Conditions
3.00
4.00
V
fCPU = 8 MHz ; USB not guaranteed
VIT+
4.00
fCPU = 8 MHz or 4 MHz
USB guaranteed
4.0
5.25
fCPU = 8 MHz or 4 MHz
USB not guaranteed
5.25
5.50
12
24
V
MHz
Note 1: USB 1.1 specifies that the power supply must be between 4.00 and 5.25 Volts. The USB cell is
therefore guaranteed only in that range.
95/109
ST7263
7.4 POWER CONSUMPTION
(TA = 0 to +70°C unless otherwise specified)
GENERAL
Symbol
Parameter
VDD
Operating Supply Voltage
Conditions
Min
Typ.
Max
Unit
4
5
5.5
V
RUN & WAIT mode
fOSC = 24 MHz
fCPU = 8 MHz
VDDA
IDD
5
5.5
V
CPU RUN mode (see Note 1)
Analog Reference Voltage
I/O in input mode
4
14
20
mA
CPU WAIT mode (See Note 2)
fCPU = 8 MHz,
8
CPU HALT mode (see Note 3)
TA = 20°C
USB Suspend mode (see Note 4)
(For VDD : see Note 5)
350
12
mA
100
µA
450
µA
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 VSSA)
connected on drivers.
Note 5:
VDD = 5.5 V except in USB Suspend mode where VDD = 5.25 V
96/109
ST7263
7.5 I/O PORT CHARACTERISTICS
(TA = 0 to +70°C unless otherwise specified)
STANDARD I/O PORT PINS
Symbol
VOL
VOH
VOH
VIH
VIL
RPU
Parameter
Conditions
Min
Typ
Max
Unit
Output Low Level Voltage Port A1,
Port A2 (High Current open drain)
IOL = -25mA VDD=5V
-
-
1.5
V
Output Low Level Voltage Port A0,
Port A(3:7), Port C(0:2), Push Pull
IOL = -1.6mA VDD=5V
-
-
0.4
V
Output Low Level Voltage Port B (0:7),
Push Pull
IOL = -10mA VDD=5V
-
-
1.3
V
Output High Level Voltage Port A0,
Port A(3:7), Port C(0:2) Push Pull
IOH = 1.6mA
VDD-0.8
-
-
V
IOH = 10mA
VDD-1.3
-
-
V
Leading Edge
0.7xVDD
VDD
V
Trailing Edge
VSS
0.3xVDD
V
VDD = 5V
80
120
kΩ
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
CIO
Pull-up resistor
I/O Pin Capacitance 1)
tf(IO)out
Output High to Low Level Fall Time
All I/O ports
tr(IO)out
Output Low to High Level Rise Time
I/O ports in Push Pull mode
tr(IO)out
External Interrupt pulse time 1)
CL=50pF
Between 10% and 90%
1
100
5
pF
25 2)
ns
25 2)
ns
tCPU
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.
97/109
ST7263
7.6 LOW VOLTAGE DETECTOR (LVD) CHARACTERISTICS
LOW VOLTAGE RESET Electrical Specifications
Symbol
VIT+
VITVhys
Parameter
Conditions
Min
Typ
Max
Unit
Low Voltage Reset Threshold
VDD Max. Variation
50mV/µs
3.6
3.75
4.0
V
VDD Max. Variation
50mV/µs
3.2
3.5
3.7
V
200
250
VDD rising
Low Voltage Reset Threshold
VDD falling
Hysteresis (VIT+ - VIT-)
mV
7.7 CONTROL TIMING CHARACTERISTICS
(Operating conditions TA = 0 to +70°C unless otherwise specified)
CONTROL TIMINGS
Symbol
Parameter
Conditions
Value
Min
Typ.
Max
Unit
fOSC
Oscillator Frequency
24
MHz
fCPU
Operating Frequency
8
MHz
tRL
External RESET
Input pulse Width
1.5
tCPU
tPORL
Internal Power Reset Duration
4096
tCPU
TDOGL
Watchdog & Low Voltage Reset
Output Pulse Width
200
ns
tDOG
tOXOV
tDDR
Watchdog Time-out
fcpu = 8MHz
Crystal Oscillator
Start-up Time
Power up rise time
from VDD = 0 to 4V
49152
3145728
tCPU
6
384
ms
50
ms
100
ms
Note 1: The minimum period t ILIL should not be less than the number of cycle times it takes to execute the
interrupt service routine plus 21 cycles.
C
98/109
ST7263
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 valid for
the product. T = 0... +70°C, VDD - VSS = 5 V unless
otherwise specified.
7.8.1 USB - Universal Bus Interface
(Operating conditions TA = 0 to +70°C, VDD = 4.0 to 5.25V unless otherwise specified)
USB DC Electrical Characteristics
Parameter
Symbol
Conditions
Min.
Max.
Unit
Input Levels:
Differential Input Sensitivity
VDI
I(D+, D-)
0.2
Differential Common Mode Range
VCM
Includes VDI range
0.8
2.5
V
V
Single Ended Receiver Threshold
VSE
0.8
2.0
V
0.3
V
Output Levels
Static Output Low
VOL
RL of 1.5K ohms to 3.6v
Static Output High
VOH
RL of 15K ohm to VSS
2.8
3.6
V
USBVCC: voltage level
USBV
VDD=5v
3.00
3.60
V
Note 1: RL is the load connected on the USB drivers.
Note 2: All the voltages are measured from the local ground potential.
99/109
ST7263
COMMUNICATION INTERFACE CHARACTERISTICS (Cont’d)
Figure 44. USB: Data signal Rise and fall time
Differential
Data Lines
Crossover
points
VCRS
VSS
tr
tf
USB: Low speed electrical characteristics
Parameter
Symbol
Conditions
Min
Rise time
tr
Note 1,CL=50 pF
75
Fall Time
tf
Rise/ Fall Time matching
trfm
Output signal Crossover
Voltage
VCRS
Max
Unit
Driver characteristics:
Note 1, CL=600 pF
Note 1, CL=50 pF
300
75
Note 1, CL=600 pF
tr/tf
ns
ns
ns
300
ns
80
120
%
1.3
2.0
V
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).
100/109
ST7263
COMMUNICATION INTERFACE CHARACTERISTICS (Cont’d)
7.8.2 I 2C - Inter IC Control Interface
I2C/DDC-Bus Timings
Parameter
Bus free time between a STOP and START condition
Standard I2C
Min
Fast I2C
Max
Min
Max
Symbol
Unit
4.7
1.3
TBUF
ms
4.0
0.6
THD:STA
µs
LOW period of the SCL clock
4.7
1.3
TLOW
µs
HIGH period of the SCL clock
4.0
0.6
THIGH
µs
Set-up time for a repeated START condition
4.7
0.6
TSU:STA
µs
Data hold time
0 (1)
0 (1)
THD:DAT
ns
Data set-up time
250
TSU:DAT
ns
TR
ns
Hold time START condition. After this period,
the first clock pulse is generated
Rise time of both SDA and SCL signals
Set-up time for STOP condition
Capacitive load for each bus line
100
1000
Fall time of both SDA and SCL signals
0.9(2)
300
4.0
20+0.1Cb
300
20+0.1Cb
300
0.6
400
400
TF
ns
TSU:STO
ns
Cb
pF
1) The device must internally provide a hold time of at least 300 ns for the SDA signal in order to bridge the undefined
region of the falling edge of SCL
2) The maximum hold time of the START condition has only to be met if the interface does not stretch the low period of
SCL signal
Cb = total capacitance of one bus line in pF
101/109
ST7263
7.9 8-BIT ADC CHARACTERISTICS
GE
Digital Result ADCDR
(1) Example of an actual transfer curve
(2) The ideal transfer curve
(3) End point correlation line
255
254
253
1LSB
i deal
V
–V
DDA
SSA
= ----------------------------------------256
(2)
(3)
TUE
7
(1)
6
5
4
ILE
OE
3
DLE
2
TUE=Total Unadjusted Error: maximum deviation
between the actual and the ideal transfer curves.
OE=Offset Error: deviation between the first actual
transition and the first ideal one.
GE=Gain Error: deviation between the last ideal
transition and the last actual one.
DLE=Differential Linearity Error: maximum deviation between actual steps and the ideal one.
ILE=Integral Linearity Error: maximum deviation
between any actual transition and the end point
correlation line.
1 LSB(ideal)
1
0
1
VSSA
Vin (LSBideal)
2
3
4
5
6
7
253 254 255 256
VDDA
ADC Analog to Digital Converter (8-bit)
Symbol
Parameter
|TUE|
Total unadjusted error*
OE
Offset error*
GE
Gain Error*
|DLE|
Differential linearity error*
|ILE|
Integral linearity error*
VAIN
Conversion range voltage
IADC
A/D conversion supply current
tSTAB
Stabilization time after enable ADC
Conditions
Min
Typ
Max
Unit
2
fADC=fCPU=4MHz
VDD=VDDA=5V
-1
1
-2
2
LSB
1
2
VSSA
VDDA
1
mA
30
fADC=fCPU=4MHz
VDD=VDDA=5V
V
µs
8
32
µs
1/fADC
8
32
µs
1/fADC
tLOAD
Sample capacitor loading time
tCONV
Hold conversion time
RAIN
External input resistor
20
ΚΩ
RADC
Internal input resistor
18
ΚΩ
22
pF
CSAMPLE Sample capacitor
*Note: ADC Accuracy vs. Negative Injection Current:
For Iinj-=0.8mA, the typical leakage induced inside the die is 1.6µA and the effect on the ADC accuracy is a loss of 1 LSB
by 10KΩ increase of the external analog source impedance.
These measurements results and recommandations are done in the worst condition of injection:
- negative injection
- injection to an Input with analog capability ,adjacent to the enabled Analog Input
- at 5V VDD supply, and worse temperature case.
102/109
ST7263
8-BIT ADC CHARACTERISTICS (Cont’d)
VDD
Sampling
Switch
VT = 0.6V
RAIN
VAIN
SS
Px.x/AINx
Cpin
VT
= input capacitance
= threshold voltage
SS
= sampling switch
Chold
= sample/hold
capacitance
leakage = leakage current
at the pin due
to various junctions
Cpin
5pF
Chold
22.4 pF
VT = 0.6V
leakage
±1µA
VSS
103/109
ST7263
8 PACKAGE CHARACTERISTICS
8.1 PACKAGE MECHANICAL DATA
Figure 45. 34-Pin Shrink Plastic Small Outline Package, 300-mil Width
mm
Dim.
0.10mm
.004
seating plane
Min
inches
Typ
Max
Min
Typ
Max
A
2.46
2.64 0.097
0.104
A1
0.13
0.29 0.005
0.0115
B
0.36
0.48 0.014
0.019
C
0.23
0.32 0.0091
0.0125
D
17.73
18.06 0.698
0.711
E
7.42
7.59 0.292
0.299
e
1.02
0.040
H
10.16
10.41 0.400
0.410
h
0.64
0.74 0.025
0.029
0.61
1.02 0.024
K
L
0°
8°
0.040
Number of Pins
N
34
SO34S
Figure 46. 32-Pin Shrink Plastic Dual in Line Package, 400-mil Width
E
Dim.
See Lead Detail
b
inches
Max
Min
Typ
5.08 0.140 0.148 0.200
A1
0.51
A2
3.05 3.56
4.57 0.120 0.140 0.180
eA
b
0.36 0.46
0.58 0.014 0.018 0.023
eB
0.020
b1
0.76 1.02
1.40 0.030 0.040 0.055
C
0.20 0.25
0.36 0.008 0.010 0.014
D
D
27.43 27.94 28.45 1.080 1.100 1.120
E
9.91 10.41 11.05 0.390 0.410 0.435
E1
7.62 8.89
A2
E1
A1
N/2
9.40 0.300 0.350 0.370
A
e
1.78
0.070
L
eA
10.16
0.400
eB
e
VR01725J
L
12.70
2.54 3.05
N
0.500
3.81 0.100 0.120 0.150
Number of Pins
104/109
Max
3.56 3.76
e3
N
1
Typ
A
C
b1
mm
Min
32
ST7263
Figure 47. 32-Pin Shrink Ceramic Dual In-Line Package
Dim.
mm
Min
Typ
A
Min
Typ
3.63
Max
0.143
A1
0.38
0.015
B
0.36
0.46 0.58 0.014 0.018 0.023
B1
0.64
0.89 1.14 0.025 0.035 0.045
C
0.20
0.25 0.36 0.008 0.010 0.014
D
29.41 29.97 30.53 1.158 1.180 1.202
D1
26.67
1.050
E
10.16
0.400
E1
CDIP32SW
inches
Max
9.45
9.91 10.36 0.372 0.390 0.408
e
1.78
G
9.40
0.070
0.370
G1
14.73
0.580
G2
1.12
0.044
L
3.30
0.130
Ø
7.37
0.290
Number of Pins
N
32
105/109
ST7263
9 DEVICE CONFIGURATION AND ORDERING INFORMATION
The following section deals with the procedure for
transfer of customer codes to STMicroelectronics.
9.1 DEVICE ORDERING INFORMATION AND TRANSFER OF CUSTOMER CODE
Customer code is made up of the ROM contents.
The ROM contents are to be sent on diskette, or
by electronic means, with the hexadecimal file in
.S19 format generated by the development tool.
All unused bytes must be set to FFh.
The customer code should be communicated to
STMicroelectronics with the correctly completed
OPTION LIST appended.
The STMicroelectronics Sales Organization will be
pleased to provide detailed information on contractual points.
Figure 48. Sales Type Coding Rules
Family
Version Code
Sub family
Subset Index
Number of pins
ROM Size Code
Package Type
Temperature Code
ROM Code (three letters)
ST72 T 63 1 K 4 B 1 / xxx
0 = 25°C
B = Plastic DIP
4 = 16K K = 32/34 pins No letter = ROM
1 = Standard (0 to +70°C) D = Ceramic DIP 2 = 8K
E = EPROM
M = Plastic SO
1 = 4K
T = OTP
Subset index : 1 = fully featured; other number = downgraded versions
Table 26. Ordering Information
Sales Type 1)
ST72E631K4D0
ST72631K4M1/xxx
ST72T631K4M1
ST72631K4B1/xxx
ST72T631K4B1
ST72632K2M1/xxx
ST72T632K2M1
ST72632K2B1/xxx
ST72T632K2B1
ST72633K1M1/xxx
ST72T633K1M1
ST72633K1B1/xxx
ST72T633K1B1
106/109
Program
Memory
(bytes)
16K EPROM
16K ROM
16K OTP
16K ROM
16K OTP
8K ROM
8K OTP
8K ROM
8K OTP
4K ROM
4K OTP
4K ROM
4K OTP
Note 1. /xxx stands for the ROM code name assigned by STMicroelectronics.
RAM
Package
(bytes)
CSDIP32
512
SO34
PSDIP32
SO34
256
PSDIP32
SO34
256
PSDIP32
Table 27. Development Tools
Development Tool
Sales Type
Real time emulator ST7263-EMU2
EPROM
Programming
Board
ST72E63-EPB/EU
ST72E63-EPB/US
Remarks
220V Power
Supply
110V Power
Supply
ST7263
ST7263X MICROCONTROLLER OPTION LIST
Customer:
Address:
....
....
....
Contact:
....
Phone No: . . . .
Reference : . . . .
.......
.......
.......
.......
.......
.......
......
......
......
......
......
......
......
......
......
......
......
......
.....
.....
.....
.....
.....
.....
STMicroelectronics references:
Device:
[ ] ST72631K4
[ ] ST72632K2
[ ] ST72633K1
Package:
[ ] Dual in Line Plastic
[ ] Small Outline Plastic
Specify conditioning
[ ] Standard (stick)
[ ] Tape & Reel
[ ] Die form
Specify conditioning
[ ] Inked unscribed wafers
[ ] Inked and scribed wafers
Special Marking:
[ ] No
[ ] Yes "_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _"
For marking, one line is possible with maximum 13 characters.
Authorized characters are letters, digits, ’.’, ’-’, ’/’ and spaces only.
We have checked the ROM code verification file returned to us by STMicroelectronics. It conforms
exactly with the ROM code file orginally supplied. We therefore authorize STMicroelectronics to
proceed with device manufacture.
Signature
............................
Date
............................
107/109
ST7263
9.2 ST7 APPLICATION NOTES
IDENTIFICATION
DESCRIPTION
PROGRAMMING AND TOOLS
AN985
EXECUTING CODE IN ST7 RAM
AN986
USING THE ST7 INDIRECT ADDRESSING MODE
AN987
ST7 IN-CIRCUIT PROGRAMMING
AN988
STARTING WITH ST7 ASSEMBLY TOOL CHAIN
AN989
STARTING WITH ST7 HIWARE C
AN1039
ST7 MATH UTILITY ROUTINES
AN1064
WRITING OPTIMIZED HIWARE C LANGUAGE FOR ST7
AN1106
TRANSLATING ASSEMBLY CODE FROM HC05 TO ST7
EXAMPLE DRIVERS
AN969
ST7 SCI COMMUNICATION BETWEEN THE ST7 AND A PC
AN970
ST7 SPI COMMUNICATION BETWEEN THE ST7 AND E²PROM
AN971
ST7 I²C COMMUNICATION BETWEEN THE ST7 AND E²PROM
AN972
ST7 SOFTWARE SPI MASTER COMMUNICATION
AN973
SCI SOFTWARE COMMUNICATION WITH A PC USING ST72251 16-BIT TIMER
AN974
REAL TIME CLOCK WITH THE ST7 TIMER OUTPUT COMPARE
AN976
DRIVING A BUZZER USING THE ST7 PWM FUNCTION
AN979
DRIVING AN ANALOG KEYBOARD WITH THE ST7 ADC
AN980
ST7 KEYPAD DECODING TECHNIQUES, IMPLEMENTING WAKE-UP ON KEYSTROKE
AN1017
USING THE ST7 USB MICROCONTROLLER
AN1041
USING ST7 PWM SIGNAL TO GENERATE ANALOG OUTPUT (SINUSOID)
AN1042
ST7 ROUTINE FOR I²C SLAVE MODE MANAGEMENT
AN1044
MULTIPLE INTERRUPT SOURCES MANAGEMENT FOR ST7 MCUS
AN1045
ST7 SOFTWARE IMPLEMENTATION OF I²C BUS MASTER
AN1046
ST7 UART EMULATION SOFTWARE
AN1047
MANAGING RECEPTION ERRORS WITH THE ST7 SCI PERIPHERAL
AN1048
ST7 SOFTWARE LCD DRIVER
AN1078
ST7 TIMER PWM DUTY CYCLE SWITCH FOR TRUE 0% or 100% DUTY CYCLE
AN1082
DESCRIPTION OF THE ST72141 MOTOR CONTROL
AN1083
ST72141 BLDC MOTOR CONTROL SOFTWARE AND FLOWCHART EXAMPLE
AN1129
PWM MANAGEMENT FOR BLDC MOTOR DRIVES USING THE ST72141
AN1130
BRUSHLESS DC MOTOR DRIVE WITH ST72141
AN1148
USING THE ST7263 FOR DESIGNING A USB MOUSE
AN1149
HANDLING SUSPEND MODE ON A USB MOUSE
AN1180
USING THE ST7263 KIT TO IMPLEMENT A USB GAME PAD
AN1182
USING THE ST7 USB LOW-SPEED FIRMWARE
PRODUCT OPTIMIZATION
AN982
USING CERAMIC RESONATORS WITH THE ST7
AN1014
HOW TO MINIMIZE THE ST7 POWER CONSUMPTION
AN1070
ST7 CHECKSUM SELFCHECKING CAPABILITY
AN1179
PROGRAMMING ST7 FLASH MICROCONTROLLERS IN REMOTE ISP
PRODUCT EVALUATION
AN910
ST7 AND ST9 PERFORMANCE BENCHMARKING
AN990
ST7 BENEFITS VERSUS INDUSTRY STANDARD
AN1086
ST7 / ST10U435 CAN-do SOLUTIONS FOR CAR MULTIPLEXING
AN1150
BENCHMARK ST72 VS PC16
AN1151
PERFORMANCE COMPARISON BETWEEN ST72254 & PC16F8
9.3 TO GET MORE INFORMATION
To get the latest information on this product please use the ST web server: http://mcu.st.com/
108/109
ST7263
10 SUMMARY OF CHANGES
Description of the changes between the current release of the specification and the previous one.
Revision
1.8
Main changes
Changed status of the document (datasheet instead of preliminary data).
Added Section 9.2 and section 9.3 on page 108.
Date
August 00
Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences
of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted
by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject
to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not
authorized for use as critical components in life support devices or systems without the express written approval of STMicroelectronics.
The ST logo is a registered trademark of STMicroelectronics
2001 STMicroelectronics - All Rights Reserved.
Purchase of I2C Components by STMicroelectronics conveys a license under the Philips I2C Patent. Rights to use these components in an
I2C system is granted provided that the system conforms to the I2C Standard Specification as defined by Philips.
STMicroelectronics Group of Companies
Australia - Brazil - China - Finland - France - Germany - Hong Kong - India - Italy - Japan - Malaysia - Malta - Morocco - Singapore - Spain
Sweden - Switzerland - United Kingdom - U.S.A.
http://www.st.com
109/109