André 's CBM IEEE488 interfaces

On these pages you will find a number of IEEE-488 interfaces for Commodore 8-bit equipment as well as one for the PC printerport. The IEEE-488 interface was used with the old CBM PET computers to connect disk drives, printers, modems and more.

IEEE 488

The main bus that connects almost all of my CBM computers and devices is the parallel IEEE488 bus, at least the version that CBM implemented in the PET and CBM-II line of computers. Not all of them are by me, but some are. There is an introduction to the IEEE-488 bus by Ruud Baltissen.

C64: The CBM IEEE488 interface for the C64 is used to connect the C64 to the IEEE488 bus. I had my own (hand-drawn) schematics here, but Wolfgang Gü nther did it with a drawing program, and dumped the ROM as well. Find the description in c64/. A readme can be found in the README file there.
The original software uses up some space in the $c*** area and completely disabled the serial IEC bus. I wrote a modification to the C64 kernal such that both busses can be used and the $c*** area is free. See the kernal pages.
VIC20: Although I never owned a VIC20, I list this one here as well for completeness. Wolfgang Gü nther made the schematics of the original CBM IEEE488 interface for the VIC20 with a drawing program, and dumped the ROM as well. Find the description in vic20/.
VC1541: The now gone 64er magazin published a modification of the VC1541 to use an IEEE488 interface. It basically implements the IEEE488 interface of the 2031 drive, the IEEE488 sister drive to the VC1541. Only the ROM code was modified such that only one of the two 8k ROM chips had to be replaced by an EPROM. Find the description in vc1541-ieee.tar.gz.
PC-LPT: This interface is listed here because I use my PC as a disk drive for my CBM equipment. Starting from ideas from Ruud Baltissen (see pc-ieee.zip) I developed this interface for the PCs LPT port and wrote the software (using some of VICE's disk emulation code). Schematics, description and software (for Linux) can be found in lptiec-0.9.2.tar.gz.
Although the software is for Linux, it is written somewhat portably in that no special kernel device or so is used. The program directly interfaces the PC LPT hardware and should easily be ported.
IEEE488->IEC: A friend of mine used the serial IEC bus and not the IEEE488 bus to connect all his stuff. Unfortunately he also used a CBM 600 (aka B128). We designed a small device - a 6502 computer actually - that is put in between the two busses, converting the parallel IEEE488 to the serial IEC bus. The schematics has longs since been lost, so I reverse-engineered it from the last existing source file for the ROM. Find the description in par2ser-1.tar.gz.

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Contents last modified 15 June 2000

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Last modified: 2010-01-03