21 Feb
2007
21 Feb
'07
5:47 a.m.
On 21 Feb 2007 at 2:25, Tony Duell wrote:
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.
If you're communicating to a single device, it's possible to use a PC
paralell port (particularly a bidirectional one) to do the job. A
very long time ago, I needed to draw a color pie chart. I had a copy
of Supercalc and a friend loaned me an HP 5-pen (IIRC) plotter that
he'd picked up at the going-out-of-business sale of the Control Data
retail stores. I had a PC XT at the time. The problem was that the
plotter was GPIB only.
I hacked the parallel port on the IBM MDA to do bidirectional I/O
(easy--just a cut and a jumper). I wrote a TSR that hooked the
parallel port BIOS interrupt and translated the codes intended for a
parallel-interface plotter to GPIB strings. I told Supercalc that it
was driving the parallel-port version of the plotter and bingo--I had
my charts.
You can probably still find the code in one of the SIMTEL archives,
but I can't remember what I called it--something like LPTHPIB, IIRC.
Cheers,
Chuck