HPIB [was Re: Kennedy to PC interface...]

[Tony Duell]

> 
> >> OK... Quick survey. How many people on the list own a HPIB bus
> >> analyzer and have ever made "real" use of it?
> > I've used a logic analyser to grab data off an HPIB interface....
> 
> Speaking of HPIB....
> 
> I wanted to build interface electronics so that one of my "modern"
> machines could act as HPIB disk for my hp300s.  While I was working on
> this, I suspect I managed to short something to soemthing else
> unfortunate and blow a driver.  It stopped working even when my
> electronics were out of the loop, and one of the bits semeed to have
> developed a stuck-at fault, hence my suspicion.
> 
> Is there anyone here who knows enough about typical HPIB hardware of
> the hp300 era to be able to take a list of chip markings and tell me
> which one is probably the relevant driver?  Preferably, also tell me

What I would do is trace back from the data pins of the HPIB connector 
(IIRC that's pins 1-4 and 13-16 of the 24 pin Microribbon connector). On 
most modern-ish machines (anything since the 9830 :-)), there is only one 
chip connected to those lines, and that's the HPIN data buffer.

One common type is the 75160, which comes in a 20 pin DIL package, or I 
guess some kind of SMD thing. But HP did make their own ASIC HPIB buffer 
chips -- I forget the number, but it's a 40 pin DIL thing. Anyway, if you 
find what chip those signals go to, post the number (even if it's an HP 
house number -- 1820-xxxx) and I'll see if I can identify it.

> enough that I can patch on a substitute (if necessary by stealing a
> driver chip from other hardware - for example, I've got a dead HPIB
> disk drive which I could raid for chips at need)?

There aren't that many HPIB buffer chips in common use. There's the TI 
set (75160/75161/75162), the HP custom one, the various Motorola ones (I 
forget the numbers), the Intel one (8293), and that's about it. Oh, 
there's the kludge way, using open-collector TTL as drivers (or before 
that, discrete transistors), and 7414's as receivers.

-tony