# Vic 20 User I/O

(at the 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
B | CB1 | CB1
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
M | CB2 | CB2
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).

Contributor: | Joakim Ögren, Nikolas Engström, Arwin Vosselman, Jestin Nesselroad, Larry Anderson

Source: | Commodore VIC-20 User Manual
| Commodore VIC-20 Programmer's Reference Guide
| NT Rautanen Tietokonesivut: Commodore

Copyright © The Hardware Book Team 1996-2004.
May be copied and redistributed, partially or in whole, as appropriate.
Document last modified: 2002-01-13