PRELIMINARY
COPYRIGHT © INTEL CORPORATION, 1996 May 1996 Order Number: 272783-003
8XC251SA/SB/SP/SQ
HIGH-PERFORMANCE
CHMOS MICROCONTROLLER
Commercial/Express
A member of the Intel family of 8-bit MCS 251 microcontrollers, the 8XC251SA/SB/SP/SQ is binary-code
compatible with MCS 51 microcontrollers and pin compatible with 40-pin PDIP and 44-pin PLCC MCS 51
microcontrollers. MCS 251 microcontrollers feature an enriched instruction set, linear addressing, and
efficient C-language support. The 8XC251SA/SB/SP/SQ has 512 bytes or 1 Kbyte of on-chip RAM and is
available with 8 Kbytes or 16 Kbytes of on-chip ROM/OTPROM/EPROM, or without ROM/OTPROM/EPROM.
A variety of features can be selected by new user-programmable configurations.
a73 Real-time and Programmed Wait State
Bus Operation
a73 Binary-code Compatible with MCS
®
51
a73 Pin Compatible with 44-pin PLCC and 40-
pin PDIP MCS 51 Sockets
a73 Register-based MCS
®
251 Architecture
— 40-byte Register File
— Registers Accessible as Bytes, Words,
or Double Words
a73 Enriched MCS 51 Instruction Set
— 16-bit and 32-bit Arithmetic and Logic
Instructions
— Compare and Conditional Jump
Instructions
— Expanded Set of Move Instructions
a73 Linear Addressing
a73 256-Kbyte Expanded External Code/Data
Memory Space
a73 ROM/OTPROM/EPROM Options:
16 Kbytes (SB/SQ), 8 Kbytes (SA/SP), or
without ROM/OTPROM/EPROM
a73 16-bit Internal Code Fetch
a73 64-Kbyte Extended Stack Space
a73 On-chip Data RAM Options:
1-Kbyte (SA/SB) or 512-Byte (SP/SQ)
a73 8-bit, 2-clock External Code Fetch in
Page Mode
a73 Fast MCS 251 Instruction Pipeline
a73 User-selectable Configurations:
— External Wait States (0-3 wait states)
— Address Range & Memory Mapping
— Page Mode
a73 32 Programmable I/O Lines
a73 Seven Maskable Interrupt Sources
with Four Programmable Priority
Levels
a73 Three Flexible 16-bit Timer/counters
a73 Hardware Watchdog Timer
a73 Programmable Counter Array
— High-speed Output
— Compare/Capture Operation
— Pulse Width Modulator
— Watchdog Timer
a73 Programmable Serial I/O Port
— Framing Error Detection
— Automatic Address Recognition
a73 High-performance CHMOS Technology
a73 Static Standby to 16-MHz Operation
a73 Complete System Development
Support
— Compatible with Existing Tools
— New MCS 251 Tools Available:
Compiler, Assembler, Debugger, ICE
a73 Package Options (PDIP, PLCC, and
Ceramic DIP)