Commodore Serial I/O
Available on the Commodore VIC-20, C64, C128, C16, C116 and +4 computers.
Pinout
6 PIN DIN (DIN45322) FEMALE at the Computer.
6 PIN DIN (DIN45322) MALE at the Cable.
| Pin | Name | Dir | Description |
|---|---|---|---|
| 1 | /SRQIN | ← | Serial SRQIN |
| 2 | GND | ─ | Ground |
| 3 | ATN | ↔ | Serial ATN In/Out |
| 4 | CLK | ↔ | Serial CLK In/Out |
| 5 | DATA | ↔ | Serial DATA In/Out |
| 6 | /RESET | ? | Reset |
Note: Direction is computer relative peripherals.
/SRQIN
Serial service request in: Any device on the serial bus can bring this signal low when it requires attention from the VIC. The VIC will then take care of the device.
ATN
Serial attention in/out: The VIC uses this signal to start a command sequence for a device on the serial bus. When the VIC brings this signal low, all other devices on the bus start listening for the VIC to transmit an address. The device addressed must respond in a preset period of time; otherwise the VIC will assume that the device addressed is not on the bus, and will return an error in the status word.
CLK
Serial clock in/out: This signal is used for timing on the serial bus.
DATA
Serial data in/out: Data on the serial bus is transmitted one bit at a time on this line.
RESET
Not connected on some VIC-20 computers.
Contributions
Sources
- SAMS Computerfacts CC8 Commodore 16.
- NT Rautanen's VIC-20 Serial I/O