isabella232 / pc1-isa

Hardware converter to allow the Commodore PC-1 computer to use 8-bit ISA cards

PC1-ISA

Hardware adapter to allow the Commodore PC-1 computer to use 8-bit ISA cards.

The smallest IBM PC compatible computer made by Commodore is the PC-1. So small in fact, that it doesn't have any 8-bit ISA expansion ports like most other IBM "clones". It does, however, have its own expansion port, a simple card-edge connector on the back of the computer which, to a degree, is compatible with the PC/XT (later and by others named ISA) slot.

The PC1-ISA adapter allows you to use an 8-bit ISA expansion card with your Commodore PC-1. Confirmed to work with this adapter is the Glich Works' XT-IDE expansion card, letting you attach an IDE harddisk, or through an IDE-CF adapter, a CF memory card acting as a hard drive. The PC-1's power supply only delivers +5V and +12V, however, so any ISA card requiring -5V or -12V will not work. Also, the later 16-bit ISA cards (with larger connectors) will not work.

How to make your own

These are the Eagle files to use if you want to print your own PCB for the PC1-ISA adapter. In addition to be PCB, you will also need:

• 1 × 60 pin (2×30) female board edge connector, 2.54 mm pitch, angled (for the PC-1 end)
• 1 × 62 pin (2×31) female board edge connector, 2.54 mm pitch, vertical or angled (for the ISA card end)
• 1 × PC internal power cable Y-splitter, 1 male to 2 female (often called a Molex power splitter, even though that might not be 100% correct)
• 1 × TE male 4 pin connector, PCB through-hole mount (Mouser no. 571-3502111)
• Eagle software as well as basic soldering and PCB manufactoring skills

How to buy

If you don't want to print your own PCB's, you can buy the PC1-ISA adapter either as a solder kit or ready-to-use from (to be announced).