GPIB (was Re: OT: Windows profanity)

From: Tony Duell <ard_at_p850ug1.demon.co.uk>
Date: Fri Mar 19 18:03:32 2004

> I do, however, have a few Texas Instruments GPIB interface ICs (SN75160BN and
> SN75161BN) in my junkbox. The GPIB connectors are standard anyway - 24-way

If you're just talking to 1 or 2 peripherals (say you want to hook up a
GPIB plotter, or you want to get the data off an HP disk drive) you can
get away without the special buffers. You can use open-collector TTL
gates to drive the bus, and TTL schmitt triggers ('14s, for example) as
receivers. Like many things I'd not do this on a 'production' board, but
it works as a hack.

You don't ened a GPIB talker/listener/controller IC. The whole bus is
designed so that the handshakes are 'interlocked' That is, something
happening in one device causes some other device to do something, then
the first deivce might do something else, etc. You can do the whole
handshake in software (Commodoer always did, in the PET and all the
peripherals), and there's no chance of missing a signal transition.
Alternatively you can make some state machines from TTL or PALs (I did
this years ago, it's not hard) if you like hardware.

I have plenty of GPIB-capable machines from handheld calculators up to
workstations (e.g. HP41 + HPIL + HP82169 translator in the first case,
PERQ in the second). I even have the Acorn interface for the Beeb.
Nothing spare, though

> Centronics-style IIRC.

Yes, 24 pin Blue Ribbon. Watch out, the screw-down jackposts have the
M3.5 thread, and as far as I know are unobtainium from any of the normal
UK catalogues. I had to spend an hour in the garage making some from
stainless steel rod...

-tony
Received on Fri Mar 19 2004 - 18:03:32 GMT