19 Dec
2009
19 Dec
'09
11:09 a.m.
Perhaps the 8291 used less code on the
microcontrollers? Or perhaps it
could do seomthing on it's own, unlike the 9914, such as assert NRDF
when it's databuffer was full? Come to think of it, wasn't the 8291
almost "smart", like a hard coded microcontroller?
I think you're thinking of the 8292, which was an add-on chip to the 8291
to give contrtoller functionality (the 8291 on its own could talk and
listen, but couldn't act as a controller). That chip was clearly a
programmed 8041 or 8042.
I still think it would be a useful project for
somebody to make a=20
HP-drive-emulator. Mot using a PC, but using a microntroller, HPIB=20
buffers, the minimal (if any) logic you need to handle HPIB, and a CF=20
card. Make it 'open' and I'll build several...
Or even a SATA, PATA, USB storage interface. Such a stand alone
emulator would be very useful. There's a fair description of the Amigo protocol
floating around as
well as the CS80 spec as a PDF on Bitsavers. Since all the HP drive
The amigo protocol is in some of the HP drive service manuals.
controllers are built around Intel microcontrollers,
shouldn't be too
Are they? While I'll believe (if shown) that such a device exists, every
HP drive I've been inside [1] uses a Motorola processor. An 6802 in the
82901, 68B09s in most others and a 68000(!) in the 9145 tape drive.
[1] OK, the 9885 doesn't. It uses the HP custom 'nonocontooller'. But
that's not an HPIB device.
the moment. I have several different ROMs for them. It
took some
experimentation to get them working right without docs or any clues
from anyone. I also have one 9133XV with a bad floppy controller.
If this is a 9133XV with the HP controllers (6809 + 9114, etc), then I
have unofficial scheamtics. The floppy controller is actually quite
simple -- most of the logic is on the top board, the lower board contains
the master clock and disk data separator. Apart from the EPROM (which is
the sama as in a 9121 IIRC), there's nothing remotely custom in there.
-tony