17 Oct
2006
17 Oct
'06
3:46 p.m.
On 10/18/06, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
Indeed... I did look first.
It wasn't a commonly-used one, but it certainly did exist.
So... does anyone recognize the Intel part numbers P82C08 or D8293
I don't know where you'd find data sheets in electronic form... (I think I have them on paper)
Those could be handy some day if I ever try to re-use the chips.
but the 8293 is a GPIB buffer
That makes sense given where the wires go, but I had just never heard
of the part before. (the 8291 was the talker/listener chip, the 8292,
actually a
programmed microcontroler
(8042?) was the GPIB contorlelr add-on).
Good call - there does happen to be an 8291 on the board, next to the
buffers, but no sign of an 8292. There _is_ an 8256, but given its location, I'm guessing it's a UART.
The number doesn't ring any bells, but I can try to look it up.
There is also a Siemens 8282 nearby that seems to link
into the 8291 -
could that be the micro-controller? It's 20 pins, and has a printed
I doubt it. It sounds more like a bus buffer. Is there any other procesor
on this board? As I said, if this is a peripheral, you'd not need the 8292.
date code such as one would see on a programmable
part.
If you want to do that, you need to make a GPIB controller. You could use
the 8293s and bit-bang the protocol using parallel interface ICs like
6522s (the 8255 has problems, since you can't reverse the direction of
the port lines.....). Or you could use something like a 9914. Personally
I'd stay away from the 8291, it's an Intel chip and we all know those are
unpleasant to use!.
If you're only linking to one or two GPIB devices, you can get away with
using 74LS14's as the receivers and something like 7438s (open-collector
outputs) as the drivers. Yes, it doesn't meet the spec but I can assure
you it'll work. If you're really curious, I have schematics for the first
HPIB interface -- the one that goes in the HP9830. That used no special
ICs at all, just TTL and discretes (I have an idea the output drivers
were discrete transistors).
And I think the 8208 was some kind of DRAM
controller.
That makes sense - it's next to a bank of 32 41256s.
What indormation do you need? If it's just
pinouts I might well be able
to tyoe them up.
Primarily, I was curious as to what the GPIB parts were - the board is
out of the scrap pile, and I was contemplating scavenging the
GPIB-related parts in the hopes of someday wiring them to some machine
to talk to Commodore-brand disks and printers.
At this point, I might or might not take the time to desolder them.
I'd save them, but I'd not use them in a new design. Keep them for the
time you have some rare device that uses them and needs to be fixed.
If you can find them, I'd go for a TMS9914 GPIB interface chip and 75160
+ 75162 buffers. They are fairly easy to find I think.
-tony