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Vic 20 Memory Expansion

Available on Commodore Vic 20 computers. On the left side.

  1               TOP              22
+-------------------//----------------+
| =================//================ |
+-----------------//------------------+
  A              BOTTOM             Z

UNKNOWN (at the Computer)

UNKNOWN CONNECTOR at the Computer.

Pin Name Description
A GND Ground
B CA0 Address 0
C CA1 Address 1
D CA2 Address 2
E CA3 Address 3
F CA4 Address 4
H CA5 Address 5
J CA6 Address 6
K CA7 Address 7
L CA8 Address 8
M CA9 Address 9
N CA10 Address 10
P CA11 Address 11
R CA12 Address 12
S CA13 Address 13
T I/O 2 Decoded I/O block 2, starting at $9130
U I/O 3 Decoded I/O block 3, starting at $9140
V S02 Phase 2 System Clock
W /NMI Non maskable Interrupt
X /RESET 6502 Reset
Y n/c Not connected
Z GND Ground
1 GND Ground
2 CD0 Data 0
3 CD1 Data 1
4 CD2 Data 2
5 CD3 Data 3
6 CD4 Data 4
7 CD5 Data 5
8 CD6 Data 6
9 CD7 Data 7
10 /BLK 1 BLK 1 (Memory location $2000 - $3fff)
11 /BLK 2 BLK 2 (Memory location $4000 - $5fff)
12 /BLK 3 BLK 3 (Memory location $6000 - $7fff)
13 /BLK 5 BLK 5 (Memory location $a000 - $bfff)
14 RAM 1 RAM 1 (Memory location $0400 - $07ff)
15 RAM 2 RAM 2 (Memory location $0800 - $0bff)
16 RAM 3 RAM 3 (Memory location $0c00 - $0fff)
17 V R/W Read/Write from Vic chip (1=R, 0=W)
18 C R/W Read/Write from CPU (1=R, 0=W)
19 /IRQ 6502 Interrupt Request
20 n/c Not connected
21 +5V +5 VDC
22 GND Ground
Contributor: Joakim Ögren
Source: Inside your Vic 20 by Ward Shrake
"The Vic Revealed" by Nick Hampshire, 1982, Hayden Book Co, Inc.
"Vic20 Programmer's Reference Guide", 1992, Commodore Business, Machines, Inc. and Howard W. Sams & Company, Inc.

Copyright © The Hardware Book Team 1996-2004.
May be copied and redistributed, partially or in whole, as appropriate.
Document last modified: 2002-01-10