C128 Expansion Bus

Available at the Commodore 128.

UNKNOWN (at the computer)

44 PIN FEMALE EDGE at the computer.

Pin	Name	Description
1	GND	System Ground
2	+5V	System Vcc
3	+5V	System Vcc
4	/IRQ	Interrupt request
5	R/W	System Read/Write Signal
6	DClock	8.18MHz Video Dot Clock
7	I/O1	I/O Chip select $de00-deff
8	/GAME	Sensed for memory map configuration
9	/EXROM	Sensed for memory map configuration
10	I/O2	I/O Chip select $df00-dfff
11	/ROML	External ROM select $8000-Bfff
12	BA	Bus available output
13	/DMA	Direct memory access input
14	D7	Data bit 7
15	D6	Data bit 6
16	D5	Data bit 5
17	D4	Data bit 4
18	D3	Data bit 3
19	D2	Data bit 2
20	D1	Data bit 1
21	D0	Data bit 0
22	GND	System Ground

A	GND	System Ground
B	/ROMH	External ROM Select $c000-ffff
C	/RESET	System Reset Signal
D	/NMI	Non-Maskable Interrupt
E	1MHz	System 1MHz clock
F	TA15	Translated address bit 15
H	TA14	Translated address bit 14
J	TA13	Translated address bit 13
K	TA12	Translated address bit 12
L	TA11	Translated address bit 11
M	TA10	Translated address bit 10
N	TA9	Translated address bit 9
P	TA8	Translated address bit 8
R	SA7	Shared address bit 7
S	SA6	Shared address bit 6
T	SA5	Shared address bit 5
U	SA4	Shared address bit 4
V	SA3	Shared address bit 3
W	SA2	Shared address bit 2
X	SA1	Shared address bit 1
Y	SA0	Shared address bit 0
Z	GND	System Ground

Contributor:

Rob Gill

Source:

Commodore 128 Programmers reference guide

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