The AT89C55WD is a low-power, high-performance CMOS 8-bit microcontroller with 20K bytes of Flash programmable read only memory and 256 bytes of RAM. The device is manufactured using Atmel’s high-density nonvolatile memory technology and is compatible with the industry standard 80C51 and 80C52 instruction set and pinout. The on-chip Flash allows the program memory to be user programmed by a conventional nonvolatile memory programmer. By combining a versatile 8-bit CPU with Flash on a monolithic chip, the Atmel AT89C55WD is a powerful microcomputer which provides a highly flexible and cost effective solution to many embedded control applications. The AT89C55WD provides the following standard features: 20K bytes of Flash, 256 bytes of RAM, 32 I/O lines, three 16-bit timer/counters, a six-vector, two-level interrupt architecture, a full-duplex serial port, on-chip oscillator, and clock circuitry. In addition, the AT89C55WD also provides power management unit and low power modes, which further reduce the system power consumption.
The AT89C55WD is a low‑power, high‑performance CMOS 8‑bit microcontroller with 20 KB of Flash memory, 256 bytes of RAM, and 32 programmable I/O lines. It operates from 4 V to 5.5 V and supports a fully static operation from 0 Hz to 33 MHz, making it suitable for a wide range of embedded control applications.
This datasheet includes a description of the device, pin configurations for TQFP, PLCC and PDIP packages, a block diagram, detailed pin descriptions, special function registers, timer and interrupt register maps, and package dimension drawings. Technical specifications such as memory sizes, voltage range, and peripheral features are listed throughout.
| Flash Memory | 20 KB |
|---|---|
| RAM | 256 bytes |
| Programmable I/O Lines | 32 |
| Operating Voltage | 4 V to 5.5 V |
| Maximum Clock Frequency | 33 MHz |
| Timer/Counters | Three 16‑bit |
| Interrupt Sources | Eight |
| Serial Channel | Programmable |
| Power‑down Modes | Idle and Power‑down |
| Endurance | 1000 Write/Erase Cycles |
The device contains 20 KB of reprogrammable flash memory.
It provides 256 bytes of internal RAM.
The AT89C55WD operates from 4 V to 5.5 V.
The microcontroller has 32 programmable I/O lines.