GPIB state machine info WTD

Ethan Dicks ethan.dicks at
Fri Sep 9 14:25:18 CDT 2005

On 9/9/05, Cini, Richard <Richard.Cini at> wrote:
> If you can find it, get a ROM dump or listing from one of the floppy drives
> like the 2031LP disk drive or the 2040 dual-drive. The 2031 is a
> 1541-looking GPIB floppy drive for the PET.

If you want to look at the circuit the 2031 uses...

(it's a 6522 VIA with 75160/75161 GPIB interface chips, much like a
similar design I saw on a 3rd party VIC-20 GPIB interface)

It's not what the original questor was after, but it might be helpful
in trying to mark up a state machine based on how Commodore
implemented GPIB (or to implement your own on another flavor of


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