2.5 to 5.5V Supply Operating Range

4MHz Maximum Clock Frequency

Fully Static operation

-40° to +85°C Operating Temperature Range

Run, Wait, Stop and RAM Retention modes

User ROM: 6,144 bytes

Data RAM: 224 bytes

EEPROM: 256 bytes

28 pin Dual-in-Line and SO plastic packages

22 Bidirectional I/O lines

6 Interrupt Wake-Up programmable input lines

16-bit Timer with Input Capture and dual

Output Compare

2V RAM Data Retention mode

Master Reset and Power-On Reset

Maskable Options for:

– Input Capture (ICAP) and Output Compare

(OCMP) signal pinouts

– PORT C Wake-Up function

– PORT A Open-Drain outputs

– PORTS A and B input Pull-Ups

– Watchdog Enabled/Disabled following Reset

– Watchdog Enabled during WAIT mode

8-bit Data Manipulation

63 Basic Instructions

17 main Addressing Modes

8x8 Unsigned Multiply instruction

True Bit Manipulation

Complete Development Support on PC/DOS

Real-Time Emulator

Full Software Package (Cross-Assembler,

Debugger)

Full Hardware Emulator

EPROM and OTP support

1 GENERAL DESCRIPTION

1.1 INTRODUCTION

The ST7294 HCMOS Microcontroller Unit is a

member of the ST7 family of Microcontrollers. The

device is based on an industry-standard 8-bit core

and features an enhanced instruction set. The

CPU may be driven by an external 4MHz clock

when the device is operated with a 5V supply, or

by a 2MHz clock when operated with a 3V supply.

Thanks to the fully static design, operation is possible

down to DC. Under software control, the

ST7294 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 ST7294 features

true bit manipulation, 8x8 unsigned multiplication

and indirect addressing modes. The device

includes a CPU, ROM, RAM, EEPROM, I/O, an

on-chip oscillator and a timer with input capture

and dual output compare systems.