Intel 8XC251SA User Manual
Preliminary

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.
■
Real-time and Programmed Wait State
Bus Operation
■
Binary-code Compatible with MCS
®
51
■
Pin Compatible with 44-pin PLCC and 40-
pin PDIP MCS 51 Sockets
■
Register-based MCS
®
251 Architecture
— 40-byte Register File
— Registers Accessible as Bytes, Words,
or Double Words
■
Enriched MCS 51 Instruction Set
— 16-bit and 32-bit Arithmetic and Logic
Instructions
— Compare and Conditional Jump
Instructions
— Expanded Set of Move Instructions
■
Linear Addressing
■
256-Kbyte Expanded External Code/Data
Memory Space
■
ROM/OTPROM/EPROM Options:
16 Kbytes (SB/SQ), 8 Kbytes (SA/SP), or
without ROM/OTPROM/EPROM
■
16-bit Internal Code Fetch
■
64-Kbyte Extended Stack Space
■
On-chip Data RAM Options:
1-Kbyte (SA/SB) or 512-Byte (SP/SQ)
■
8-bit, 2-clock External Code Fetch in
Page Mode
■
Fast MCS 251 Instruction Pipeline
■
User-selectable Configurations:
— External Wait States (0-3 wait states)
— Address Range & Memory Mapping
— Page Mode
■
32 Programmable I/O Lines
■
Seven Maskable Interrupt Sources
with Four Programmable Priority
Levels
■
Three Flexible 16-bit Timer/counters
■
Hardware Watchdog Timer
■
Programmable Counter Array
— High-speed Output
— Compare/Capture Operation
— Pulse Width Modulator
— Watchdog Timer
■
Programmable Serial I/O Port
— Framing Error Detection
— Automatic Address Recognition
■
High-performance CHMOS Technology
■
Static Standby to 16-MHz Operation
■
Complete System Development
Support
— Compatible with Existing Tools
— New MCS 251 Tools Available:
Compiler, Assembler, Debugger, ICE
■
Package Options (PDIP, PLCC, and
Ceramic DIP)
Document Outline
- 8XC251SA/SB/SP/SQ HIGH-PERFORMANCE CHMOS Microcont...
- Copyright Page
- 1.0 Nomenclature
- 2.0 Pinout
- 3.0 Signals
- 4.0 Address map
- 5.0 Electrical Characteristics
- 6.0Thermal characteristics
- 7.0 Nonvolatile memory Programming and Verificatio...
- 8.0 Errata
- 9.0 Revision History
- FIGURES
- Figure 1. 8XC251SA/SB/SP/SQ Block Diagram
- Figure 2. The 8XC251SA/SB/SP/SQ Family Nomenclatur...
- Figure 3. 8XC251SA/SB/SP/SQ 44-pin PLCC Package
- Figure 4. 8XC251SA/SB/SP/SQ 40-pin PDIP and Cerami...
- Figure 5. IPD Test Condition, Powerdown Mode, Vcc ...
- Figure 6. Icc vs. Frequency (Mhz)
- Figure 7. External Bus Cycle: Code Fetch (Nonpage ...
- Figure 8. External Bus Cycle: Data Read (Nonpage M...
- Figure 9. External Bus Cycle: Data Write (Nonpage ...
- Figure 10. External Bus Cycle: Code Fetch (Page Mo...
- Figure 11. External Bus Cycle: Data Read (Page Mod...
- Figure 12. External Bus Cycle: Data Write (Page Mo...
- Figure 13. External Bus Cycle: Code Fetch/Data Rea...
- Figure 14. External Bus Cycle: Data Write (Nonpage...
- Figure 15. External Bus Cycle: Code Fetch/Data Rea...
- Figure 16. External Bus Cycle: Data Write (Page Mo...
- Figure 17. Serial Port Waveform — Shift Register M...
- Figure 18. External Clock Drive Waveforms
- Figure 19. AC Testing Input, Output Waveforms
- Figure 20. Float Waveforms
- Figure 21. Timing for Programming and Verification...
- TABLES
- Table 1. Description of Product Nomenclature
- Table 2. Proliferation Options
- Table 3. Package Information
- Table 4. 8XC251SA/SB/SP/SQ Pin Assignment
- Table 5. 8XC251SA/SB/SP/SQ PLCC/DIP Pin Assignment...
- Table 6. Signal Descriptions (Continued)
- Table 7. Memory Signal Selections (RD1:0)
- Table 8. 8XC251SA/SB/SP/SQ Address Map
- Table 9. DC Characteristics at Vcc = 4.5 – 5.5 V (...
- Table 10. AC Timing Symbol Definitions
- Table 11. AC Characteristics(Continued)
- Table 12. Real-time Wait Timing Symbol Definitions...
- Table 13. Real-time Wait AC Timing
- Table 14. Serial Port Timing — Shift Register Mode...
- Table 15. External Clock Drive
- Table 16. Thermal Characteristics
- Table 17. Nonvolatile Memory Timing Symbol Definit...
- Table 18. Nonvolatile Memory Programming and Verif...