The 8XC251SA/SB/SP/SQ is a member of the Intel family of 8-bit MCS 251 microcontrollers. It 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.
The Intel 8XC251SA/SB/SP/SQ family is a high‑performance CHMOS 8‑bit microcontroller compatible with the MCS‑51 instruction set and pin layout. It offers configurable memory options, programmable I/O, timers, watchdog and serial interfaces for flexible system design.
The datasheet provides detailed pin assignments, package options (44‑pin PLCC, 40‑pin PDIP, 40‑pin Ceramic DIP), memory configurations, and electrical specifications to aid hardware engineers in integrating the device into their applications.
| Maximum external clock frequency | 16 MHz |
|---|---|
| On‑chip RAM | 1 KB (SA/SB) or 512 B (SP/SQ) |
| On‑chip ROM/OTPROM/EPROM | 8 KB (SA/SP), 16 KB (SB/SQ), or none |
| Programmable I/O lines | 32 |
| Maskable interrupt sources | 7 |
| 16‑bit timer/counters | 3 |
| External wait states | 0‑3 |
| Hardware watchdog timer | Yes |
The device supports up to a 16 MHz external clock frequency.
It provides 32 programmable I/O lines.