Commodore 128 Pinouts

6 Pin Serial Port
Pin Direction
 Type
1 Serial SRQ In
2
GND
3 Serial ATN Out
4 Serial CLK In/Out
5 Serial DATA In/Out
6
Reset
8 Pin Din (Din45326) Port



Audio/Composite Video Connector

Pin Direction
 Type
1
Luminance/Sync Monochrome
2
GND
3 Audio Out
4 Video Out
5
Audio In (into the SID chip)
6 Chrominance
7
NC
8
NC

9 Pin D-SUB Connector



80 Column RGBI Video Connector
Pin: Name: Direction: Description:
1 GND
Ground
2 GND
Ground
3 R Red
4 G Green
5 B Blue
6 I Intensity
7 Video Composite Video
8 HSYNC Horizontal Sync
9 VSYNC Vertical Sync
5 Pin  Power Connector





Note: Power AC lines are in opposite phases.
Pin: Name:
1 +5 Volts DC
2 Ground
3 9 Volts AC
4 Ground
5 9 Volts AC


44 Pin Expansion Bus

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
24 Pin User I/O Port
Pin Type Note
1 GND
2 +5V MAX. 100 mA
3 /RESET
4 CNT1
5 SP1
6 CNT2
7 SP2
8 /PC2
9 SER. ATN out
10 9 VAC MAX. 100 mA
11 9 VAC MAX. 100 mA
12 GND



A
 GND
 Protective Ground
B+C
 FLAG2+PB0 Receive Data (Must be applied to both pins!)
D
 PB1 Ready To Send
E
 PB2 Data Terminal Ready
F
 PB3 Ring Indicator
H
 PB4 Data Carrier Detect
J
 PB5
K
 PB6 Clear To Send
L
 PB7
 Data Set Ready
M
 PA2
 Transmit Data
N
 GND
 Signal Ground
12 Pin Cassette Port
Pin Type
A+1 GND
B+2 +5V
C+3 Cassette Motor
D+4 Cassette Read
E+5 Cassette Write
F+6 Cassette Sense
9 Pin Joystick Ports




Note: Pot is a linear 470 kOhm (±10 %)

Control Port 1

Pin Name Dir Comment
1 JoyA0 Up
2 JoyA1 Down
3 JoyA2 Left
4 JoyA3 Right
5 Pot AY  
6 Button A / LP  
7 +5V 50 mA max
8 GND
Ground
9 Pot AX  

Control Port 2

Pin Name Dir Comment
1 JoyB0 Up
2 JoyB1 Down
3 JoyB2 Left
4 JoyB3 Right
5 Pot BY  
6 Button B  
7 +5V 50 mA max
8 GND
Ground
9 Pot BX