80C851/83C851 is a high-performance microcontroller fabricated with Philips high-density CMOS technology. It has 8-bit CPU, 4k × 8 ROM, 128 × 8 RAM, 256 × 8 EEPROM, 32 I/O pins, two 16-bit counters/timers, seven-source, five vector, two-priority level nested interrupt structure, serial I/O port, on-chip oscillator and clock circuits.
The 80C851/83C851 is a CMOS single‑chip 8‑bit microcontroller with on‑chip EEPROM, offering the same instruction set as the 80C51 while providing high speed, low power operation. It includes 4 KB ROM, 128 B RAM, 256 B EEPROM, 32 I/O lines, two 16‑bit timers, and a full‑duplex serial port.
The document provides a description of the device, ordering information, pin configurations and functions, EEPROM interface details, special function registers, timer register values, and notes on product status and usage warnings.
| ROM size | 4 KB (4k × 8) |
|---|---|
| RAM size | 128 B (128 × 8) |
| EEPROM size | 256 B (256 × 8) |
| I/O lines | 32 |
| Counter/Timers | Two 16‑bit counters/timers |
| Operating frequency range | 1.2 – 16 MHz or 3.5 – 24 MHz |
The device provides 32 I/O lines.
The microcontroller supports an idle mode and a power‑down mode.