PET IEEE-488 Extension
Content
Introduction
There are two reasons, why I have designed the PET IEEE-488 extension:
- The IEEE-488 cables with the edge connector are about as expensive as the peripherals (in 2021).
- 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":
The 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
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 tfw8bit.com 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.
Github
This project is open hardware and can be founs in my github repositories: https://github.com/svenpetersen1965/PET-IEEE-488-Extension