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PET IEEE-488 Extension

There are two reasons, why I have designed the PET IEEE-488 extension:
  1. The IEEE-488 cables with the edge connector are about as expensive as the peripherals (in 2021).
  2. The SD2PET future does not allow to connect other peripherals.

This project consists of 3 different PCBs:
1. The Base Board with Centronics connector (the standard IEEE-488 connector)
2. The Base Board with an edge connector
3. A Riser Card with and edge connector

Baseboard with Centronics connector

Base with Centronics connector

The Base with 24p. Centronics (female) connector can be used as an adapter for standard IEEE-488 cables, which are stilöl available for a bearable price. Part of the project is a 3D printed case that fits the Base without the box connector. The latter is not required, if the Centronics Base is used as an adapter, only.

Centronics Base with a 3D printed case

The standard cable can be purchased from e.g. AliExpress, ebay or Amazon:

IEEE488 cable/GPIB cable on AliExpress

The Centronics connector is a
Female Centronics Connector 24 Pin 90°. The search term on Ali Express is "Series 57":

Connector on AliExpress

Base Board with Edge Connector
This Base Board can be used as a very simple solution to connect a DIY IEEE-488 ribbon cable to the IEEE port of the PET or other adaptation purposes.

Base with edge connector

DIY IEEE-488 ribbon cable

The ribbon cable should not be very long, since the properties of a ribbon cable are not as good as the standard IEEE-488 cable.

The used IDC Centronics connector (24pin male) can be found on AliExpress:
57 Series 24 pin male connector

IEEE-488 Extension Base Board with ribbon cables

Riser Card
The Riser Card can be mounted on two 15mm standoffs and connected with a ribbon cable/jumper cable. Its main purpose is being a splitter for a device with edge connector, like the
SD2PET future.

The SD2PET future connected to the riser card and the centronics base

Note: To connect both, the SD2PET future and a CBM8050 floppy disk drive, the CBM8050 needs to be hardwired to a device address other than 8. The maximum load capacity of the SD2PET is not specified, so it might be a good idea to connect just one other peripheral to the IEEE bus. Also, keeping the cable short is a good choice. This configuration was tested with a 1.5 meter cable and a CBM8050 switched to device addess 9. All my old 8050 floppy disks could be flawlessly copied to SD card this way.

This project is open hardware and can be founs in my github repositories: