The 82C55 is a high-performance, CHMOS version of the industry-standard 8255A general-purpose programmable I/O device which is designed for use with all Intel and most other microprocessors. It provides 24 I/O pins which may be individually programmed in 2 groups of 12 and used in 3 major modes of operation.
The 82C55A is pin-compatible with the NMOS 8255A and 8255A-5. In MODE 0, each group of 12 I/O pins may be programmed in sets of 4 and 8 to be inputs or outputs. In MODE 1, each group may be programmed to have 8 lines of input or output. 3 of the remaining 4 pins are used for handshaking and interrupt control signals. MODE 2 is a strobed bi-directional bus configuration.
82C55 Pinout
82C55 Pin Configuration
| Pin No | Pin Name | Description |
|---|---|---|
| 1-4 | PA0-PA3 | Port A |
| 5 | RD | Read (Active Low) |
| 6 | CS | Chip Select (Active Low) |
| 7 | GND | Ground |
| 8 | A0 | Address Input |
| 9 | A1 | Address Input |
| 10-17 | PC0-PC7 | Port C |
| 18-25 | PB0-PB7 | Port B |
| 26 | Vcc | +5V Power Supply |
| 27-34 | D0-D7 | Data Bus |
| 35 | RESET | Reset Input |
| 36 | WR | Write (Active Low) |
| 37-40 | PA4-PA7 | Port A |
82C55 Key Features
- 24 Programmable I/O Pins
- Low Power CHMOS
- Completely TTL Compatible
- Control Word Read-Back Capability
- Direct Bit Set/Reset Capability
- 2.5 mA DC Drive Capability on all I/O Port Outputs
You can download this datasheet for 82C55 Programmable Peripheral I/O – Datasheet from the link given below:
