Game controller port

The VIC-20's game controller port is a common 9-pin, male, sub-D connector located on the right side of the VIC-20 (as seen by a user sitting in front of the computer). As its name suggests, this port was mostly used to connect joystick and paddle controllers to the VIC-20 for use in game-play. Specific pins in this connector were designed for either analogue or digital input/output.

Less frequently, this port was also used to connect light-pens, graphic tablets, number keypads and a range of user-built custom input/output hardware.

The VIC-20's game controller port is pin-compatible to that established for the earlier Atari 2600 video game console. As such, most controllers for the Atari 2600 will work with the VIC-20 and vice-versa.

The VIC-20 offered only one game controller port while most other consoles and computers of the day offered at least two. This was seen as a limitation but was overcome by adapting the keyboard to allow for simultaneous two-player games. Several third party manufacturers created hardware that allowed an additional game connector to be attached to the VIC-20's user port.

Pinout

Pin	Connection	Use
1	VIA #1 PA2	Joy up
2	VIA #1 PA3	Joy down
3	VIA #1 PA4	Joy left, paddle X fire
4	VIA #2 PB7	Joy right, paddle Y fire
5		Pot Y
6	VIA #1 PA5	Joy fire, light pen
7	+5V
8	GND
9		Pot X