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Index
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Model:
Commodore VIC-20 ( VIC-20 )
Release Date:
January 1981
Original Price:
$299
Processor:
MOS Technologies 6502 1 MHz
Memory:
5 KB RAM / 16 KB ROM
A first in many regards, the Commodore VIC-20 was (and still is) a landmark in
computer history. The VIC-20 was the first computer to be sold in the retail giant
K-Mart and, in 1983, became the first computer ever to sell over one million units
with 2.5 million being sold by the time it was discontinued in 1985. Although it's
cult following today isn't as impressive as that of the C64, the little VIC-20
still has it's share of devotees and applications.
Available interface ports include tape drive (using a PET-standard Datasette),
serial bus for disk drives (which weren't released until 82) and printers, an
RS-232 compatible user port (most often used to connect a modem) and a single
DB9 male joystick port. The final, and probably one of the most important port
was the cartridge port that allowed for software cartridges and additional
memory. Video output was provided through a composite output.
The graphics chip, a 6560, also doubled as the sound chip providing three voices
in three octaves. In text mode, 256 different 8 x 8 pixel characters could be be
displayed at a time on a 22 x 23 screen. Graphics mode was 184 x 176 with eight
character colors and sixteen background colors - a far cry from high-resolution.
This excellent addition to my little computer museum was acquired through ebay
a while back. It included the base unit itself, a Datasette cassette, dozens of
software applications and games on both cartridge and cassette as well as plenty
of reference materials.
>>
Click here to download the User Manual (23.0 mb)
>>
Click here to download the Programmer's Reference Guide
(41.4 mb)
>>
manuals were scanned by Richard A. Cini, Jr. and used by permission
>>
Click here to download a Complete Game List
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Pinouts:
5-pin DIN Video
Pin 1 --> +5vdc regulated (10 mA max)
Pin 2 --- Ground
Pin 3 --> Audio Out
Pin 4 --> Video Low
Pin 5 --> Video High
Controller Ports
Pin 1 <-- JOY0
Pin 2 <-- JOY1
Pin 3 <-- JOY2
Pin 4 <-- JOY3
Pin 5 <-> POT Y
Pin 6 <-> Button/Light Pen
Pin 7 --> +5vdc 100mA max
Pin 8 --- Ground
Pin 9 <-> POT X
Cassette Interface
Pin A-1 --- Ground
Pin B-2 --> +5vdc
Pin C-3 --> Cassette Motor
Pin D-4 <-- Cassette Read
Pin E-5 --> Cassette Write
Pin F-6 --> Cassette Sense
Serial I/O
Pin 1 <-- Serial SRQIN
Pin 2 --- Ground
Pin 3 <-> Serial ATN
Pin 4 <-> Serial CLK
Pin 5 <-> Serial DATA
Pin 6 <-> /RESET
| Memory Expansion Port |
 |
| Pin 01 = GND | Pin 23 = GND |
| Pin 02 = CD0 | Pin 24 = CA0 |
| Pin 03 = CD1 | Pin 25 = CA1 |
| Pin 04 = CD2 | Pin 26 = CA2 |
| Pin 05 = CD3 | Pin 27 = CA3 |
| Pin 06 = CD4 | Pin 28 = CA4 |
| Pin 07 = CD5 | Pin 29 = CA5 |
| Pin 08 = CD6 | Pin 30 = CA6 |
| Pin 09 = CD7 | Pin 31 = CA7 |
| Pin 10 = /BLK1 | Pin 32 = CA8 |
| Pin 11 = /BLK2 | Pin 33 = CA9 |
| Pin 12 = /BLK3 | Pin 34 = CA10 |
| Pin 13 = /BLK5 | Pin 35 = CA11 |
| Pin 14 = /RAM1 | Pin 36 = CA12 |
| Pin 15 = /RAM2 | Pin 37 = CA13 |
| Pin 16 = /RAM3 | Pin 38 = I/O2 |
| Pin 17 = VR/W | Pin 39 = I/O3 |
| Pin 18 = CR/W | Pin 40 = S/O2 |
| Pin 19 = /IRQ | Pin 41 = /NMI |
| Pin 20 = n/c | Pin 42 = /RESET |
| Pin 21 = +5vdc | Pin 43 = n/c |
| Pin 22 = GND | Pin 44 = GND |
| User Expansion Port |
 |
| Pin 01 = GND | Pin 13 = GND |
| Pin 02 = +5vdc (100 mA max) | Pin 14 = CB1 |
| Pin 03 = /RESET | Pin 15 = PB0 |
| Pin 04 = JOY0 | Pin 16 = PB1 |
| Pin 05 = JOY1 | Pin 17 = PB2 |
| Pin 06 = JOY2 | Pin 18 = PB3 |
| Pin 07 = LightPen | Pin 19 = PB4 |
| Pin 08 = CassetteSwitch | Pin 20 = PB5 |
| Pin 09 = ATN | Pin 21 = PB6 |
| Pin 10 = +9vac (+ phase) | Pin 22 = PB7 |
| Pin 11 = +9vac (- phase) | Pin 23 = CB2 |
| Pin 12 = GND | Pin 24 = GND |
All Pin-Outs Are Taken From the VIC-20 User Manual
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