/sinclair/zxspectrum/articles.html">Commodore 64/128 ArticlesC128 Ports and Pinouts

C128 Ports and Pinouts

Two 9 pin D-sub males (D9M) at the computer.

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

Note: In Commodore 128 the pin 7 (+5 V) is max. 50 mA

Note that when a 1350 (rolling joystick) mouse is used, pins 1 through 4 will have pulses on them instead of logic low levels as a joystick would provide. Also, a pressed right mouse button grounds pin 9. The POT lines are otherwise unused by a 1350. When a 1351 (proportional) mouse, a paddle, or graphics tablet is used, the two POT lines are used for direction control. A pressed right mouse button grounds pin 1.

Source: Commodore 64 User Manual, Commodore 128 Programmer's Reference Guide


C128 Power Supply

Connector at the Commodore 128.

 Pin Name Power
1 +5Vdc 2.5A
2 n/c  
3 9Vac 1A
4 Ground  
5 9Vac 1A

Note: the square metal shell of the plug is also a ground.

Source: Ray Carlsen's C= Repair Articles



Commodore 64/128 Cartridge Expansion Slot



44 pin female edge at the computer. The pins function as described below:

1 GND System ground. All four ground lines are usually tied together.
2,3 +5VDC 5-volt power supply to the cartridge. (Total user port and cartridge devices can draw no more than 450 mA.)
4 /IRQ IRQ. As long as this is low, it requests an interrupt.
5 R/W Read/write line. Reads when low, writes when high.
6 DOT CLOCK 8.18 MHz video dot clock input, for your own video control.
7 /I/O1 I/O 1 goes low when 64 detects use of $DE00-$DEFF; can be used with