Key facts
- Brand
- Atmel
- Model
- AT89S51
- Category
- Other Electronics
- Industry
- Electronics
- Documents
- 2
- Languages
- EN · ZH
- Last added
- 2012-05-11
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Atmel AT89S51 User Manual
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.
Atmel AT89S51 specifications
| Flash Memory | 4 KB |
|---|---|
| Internal RAM | 128 bytes (8‑bit) |
| Programmable I/O Lines | 32 |
| Timer/Counters | Two 16‑bit |
| UART | Full‑duplex serial channel |
| Operating Voltage | 4.0 V to 5.5 V |
| Maximum Clock Frequency | 33 MHz |
| Watchdog Timer | Present |
| Low‑Power Modes | Idle and Power‑down |
All Atmel AT89S51 documents by type
Ratings, dimensions and ordering codes, for selection and design work.
Day-to-day operation, settings and troubleshooting. Start here if the product is already set up.
Questions answered in these manuals
What is the flash memory size of the AT89S51?
The AT89S51 contains 4 KB of in‑system programmable flash memory.
How many programmable I/O pins does the AT89S51 provide?
It provides 32 programmable I/O lines.
What does the reset (RST) pin require to reset the device?
When the oscillator is running, the RST pin must be held high for at least two machine cycles to reset the microcontroller.
How many interrupt vectors does the AT89S51 have?
The AT89S51 provides five interrupt vectors: two external interrupts, two timer interrupts, and one serial interrupt.