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AT89C55WD 40-Pin 24MHz 20kb Microcontroller Datasheet
Photograph
Features
- Compatible with MCS-51 Products
- 20K Bytes of In-System Reprogrammable Flash Memory
- 4V to 5.5V Operating Range
- Fully Static Operation: 0 Hz to 24 MHz
- Three-level Program Memory Lock
- 256 x 8-bit Internal RAM
- 32 Programmable I/O Lines
- Three 16-bit Timer/Counters
- Eight Interrupt Sources
- Programmable Serial Channel
- Low-power Idle and Power-down Modes
- Hardware Watchdog Timer
- Dual Data Pointer
- Power-off Flag
- 40-pin DIP
Pin Layout
Pin Description
| Pin Number | Description |
|---|---|
| 1 - 8 | P1.0 - P1.7 - Port 1 |
| 9 | RST - Reset |
| 10 - 17 | P3.0 - P3.7 - Port 3 |
| 18 | XTAL2 - Crystal |
| 19 | XTAL1 - Crystal |
| 20 | GND - Ground |
| 21 - 28 | P2.0 - P2.7 - Port 2 |
| 29 | PSEN - Program Store Enable |
| 30 | ALE - Address Latch Enable |
| 31 | EA - External Access Enable |
| 32 - 39 | P0.7 - P0.1 - Port 0 |
| 40 | Vcc - Positive Power Supply |
Dimensional Drawing
Technical Data
