This document introduces the features of the AT89C51ED2 chip, including 80C52 compatibility, 8051 instruction compatibility, six 8-bit I/O ports, three 16-bit timers/counters, 256 bytes of erasable scratchpad RAM, 9 interrupt sources, 4 priority levels, integrated power monitor, ISP (in-system programming), 2048 bytes of boot ROM, etc.
The AT89C51RD2/ED2 is a high‑performance CMOS 8‑bit microcontroller compatible with the 80C52 core. It provides up to 64 KB of on‑chip Flash program/data memory, 1792 bytes of expanded XRAM, and a 2048‑byte EEPROM block (ED2 variant) for non‑volatile storage. The device supports a wide operating voltage range of 2.7 V to 5.5 V and can run at clock speeds from 20 MHz up to 60 MHz, offering flexible power‑saving modes such as Idle and Power‑down.
Key peripherals include three 16‑bit timer/counters, a programmable counter array, full‑duplex UART with baud‑rate generator, SPI master/slave, keyboard interface, and a hardware watchdog timer. The microcontroller is offered in PLCC44, VQFP44, PLCC68 and VQFP64 packages and is rated for industrial temperature ranges from –40 °C to +85 °C.
| Flash Memory | 64 KB |
|---|---|
| Expanded RAM (XRAM) | 1792 bytes |
| EEPROM (ED2 variant) | 2048 bytes |
| Operating Voltage | 2.7 V to 5.5 V |
| Operating Temperature | -40 °C to +85 °C |
| Package Types | PLCC44, VQFP44, PLCC68, VQFP64 |
| Interrupt Sources | 9 sources, 4 priority levels |
| Timer/Counters | Three 16‑bit timers |
| Flash Write Endurance | 100 k cycles |
| Maximum Clock Frequency | Up to 60 MHz |
The device includes 64 KB of on‑chip Flash program and data memory.
It operates from a single supply of 2.7 V to 5.5 V.
The microcontroller provides nine interrupt sources with four priority levels.
It is available in PLCC44, VQFP44, PLCC68 and VQFP64 packages.