The AT89S51 is a low-power, high-performance CMOS8-bit microcontroller produced by ATMEL Corporation. The chip contains 4k bytes of in-system programmable Flash read-only program memory. The device is produced using ATMEL's high-density, non-volatile storage technology and is compatible with the MCS-51 product instruction system and pins. It integrates Flash program storage devices that can be programmed both online (ISP) and by conventional methods and general 8-bit microprocessors on a single chip. ATMEL's powerful and low-priced AT89S51 microcontroller can provide you with many cost-effective applications and can be flexibly applied to various control fields.
The AT89S51 is an 8‑bit flash microcontroller from Atmel featuring low power consumption, 128 bytes of internal RAM, 32 programmable I/O pins, and a range of on‑chip peripherals such as timers, UART, and a watchdog timer. It supports the standard 8051 instruction set and can be programmed in‑system via ISP or traditional methods.
The manual details the pin‑out, special function registers, auxiliary registers, clock and oscillator circuitry, interrupt sources, and the procedures for enabling and using the watchdog timer, UART, timers, and power‑saving modes. It also includes package dimensions for the PDIP variants. This manual is written in Chinese.
| Operating voltage range | 4.0 V – 5.5 V |
|---|---|
| Internal RAM | 128 bytes |
| Programmable I/O pins | 32 pins |
| Watchdog timer counter width | 14‑bit |
When the oscillator is running, the RST pin must be held high for at least two machine cycles to reset the microcontroller.
The AT89S51 provides five interrupt vectors: two external interrupts, two timer interrupts, and one serial interrupt.