The 8XC251SA/SB/SP/SQ is a member of Intel's family of 8-bit MCS 251 microcontrollers, and 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 8XC251SA/SB/SP/SQ family is a high‑performance CHMOS 8‑bit microcontroller compatible with MCS‑51 instruction set and pin‑compatible with 40‑pin PDIP and 44‑pin PLCC sockets. It offers a 40‑byte register file, linear addressing, and expanded external memory space up to 256 KB.
Key features include selectable on‑chip RAM (1 KB or 512 B), ROM/OTPROM/EPROM options (8 KB, 16 KB, or none), 32 programmable I/O lines, three 16‑bit timers/counters, a hardware watchdog timer, and a programmable serial I/O port. The device is available in PDIP, PLCC, and ceramic DIP packages and operates from 0 to 16 MHz with a 5 V ±10 % supply.
| Device Speed | 0 - 16 MHz; 5 V ±10 % |
|---|---|
| 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 |
| Interrupt Sources | Seven maskable with four priority levels |
| Timer/Counters | Three flexible 16‑bit |
| Watchdog Timer | Hardware |
| Package Options | PDIP, PLCC, Ceramic DIP |
It provides 32 programmable I/O lines.
The microcontroller is available in 44‑pin PLCC, 40‑pin PDIP, and 40‑pin ceramic DIP packages.
They operate from 0 MHz up to 16 MHz with a 5 V ±10 % supply.