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The 80C31 contains a 4k × 8 ROM, a 128 × 8 RAM, 32 I/O lines, three 16-bit counter/timers, a six-source, four-priority level nested interrupt structure, a serial I/O port for either multi-processor communications, I/O expansion or full-duplex UART, and on-chip oscillator and clock circuits.
In addition, the device is a low-power static design that offers a wide range of operating frequencies down to zero. Two software-selectable modes of power reduction—idle mode and power-down mode are available. The idle mode freezes the CPU while allowing the RAM, timers, serial port, and interrupt system to continue functioning.
P80C31 Pinout
P80C31 Pin Configuration
| Pin Number | Pin Name | Description |
|---|---|---|
| 1-8 | P1.0-P1.7 | Port 1 |
| 9 | RST | Reset |
| 10 | P3.0/RXD | Port 3.0 / Serial Receive Pin |
| 11 | P3.1/TXD | Port 3.1 / Serial Transmit Pin |
| 12 | P3.2/INT0 | Port 3.2 / Interrupt 0 (Active Low) |
| 13 | P3.3/INT1 | Port 3.3 / Interrupt 1 (Active Low) |
| 14 | P3.4/T0 | Port 3.4 / Timer 0 |
| 15 | P3.5/T1 | Port 3.5 / Timer 1 |
| 16 | P3.6/WR | Port 3.6 / Write (Active Low) |
| 17 | P3.7/RD | Port 3.7 / Read (Active Low) |
| 18 | XTAL2 | Crystal Input |
| 19 | XTAL1 | Crystal Input |
| 20 | Vss | Ground |
| 21-28 | P2.0-P2.7 | Port 2 |
| 29 | PSEN | Program Store Enable (Active Low) |
| 30 | ALE | Address Latch Enable |
| 31 | EA | External Memory Enable (Active Low) |
| 32-39 | P0.7-P0.1 | Port 0 |
| 40 | Vcc | Positive Supply |
P80C31 Key Features
- 8051 Central Processing Unit
- 4k × 8 ROM (80C51)
- 128 × 8 RAM
- Three 16-bit counter/timers
- Boolean processor
- Full static operation
- Memory addressing capability
- 64k ROM and 64k RAM
- Power control modes:
- Clock can be stopped and resumed
- Idle mode
- Power-down mode
You can download this datasheet for P80C31 CPU with 128×8 RAM and I/O (ROMless) – Datasheet from the link given below:
