VIC-20 User I/O

From HwB

Available at the Commodore VIC-20 computer.



24 PIN MALE EDGE (DZM 12 DREH) at the computer.

Pin Name Description
1 GND Ground
2 +5V +5 VDC (100 mA max)
3 /RESET Reset, will force a Cold Start. Also a reset output for devices.
4 JOY0 This pin is connected to joystick switch 0 (See game port).
5 JOY1 This pin is connected to joystick switch 1 (See game port).
6 JOY2 This pin is connected to joystick switch 2 (See game port).
7 LIGHT PEN This pin also acts ad the input for the joystick fire button (See game port).
8 CASSETTE SWITCH This pin is connected to the sense cassette switch line.
9 ATN Serial Attention In
10 +9V AC +9 VAC (+ phase)
11 +9V AC +9 VAC (- phase)
12 GND Ground
A GND Ground
C PB0 Data 0
D PB1 Data 1
E PB2 Data 2
F PB3 Data 3
H PB4 Data 4
J PB5 Data 5
K PB6 Data 6
L PB7 Data 7
N GND Ground

Note: 0.156" (3.96mm) contact spacing.

The VIC gives you complete control over Port B on VIA chip #1. Eight lines for input or output are available, as well as 2 lines for handshaking with an outside device. The I/O lines for Port B are controlled by two locations. One is the port itself, and is located at 37136 ($9110 hex). Naturally you PEEK it to read an input, or POKE it to set an output. Each of the eight I/O lines can be set up as either an input or an output by setting the data direction register properly. It is located at 37138 ($9112 hex).