On Dec 5, 2012, at 11:24 AM, Chris Elmquist wrote:
It's got firmware on it that the '11 executes
when you enable the ROM
and then jump to that from ODT. That firmware provides a user interface
for configuring the card and each of the target devices as well as the
means to then boot from a specific device. I use that user interface
to ge it to boot from one of the ZIPs.
The CQD-220 (QBUS) one is similar, though my 11/23+ has the
capability to boot MSCP/TMSCP devices directly, so I use that.
I wonder if anyone has attempted to archive the
firmware and PALs on
these SCSI cards?
Haha, funny you should mention that. I had to dump and disassemble
it to figure out why my card was bricked (helpful hint: NEVER set
the number of disks and tapes to zero). The CQD-220, which may or
may not be related to the CDU-720, is a pretty standard 8086 design
with a small amount of SRAM. The ROM image is actually a DOS
executable, which makes me wonder if their development machines
were 8086 PCs.
I believe someone (who can name himself if he'd like, though I don't
want to run the risk of incurring the wrath of the Attack Lawyers on
someone else) has a bunch of images of various firmware versions, at
least for the CQD-220. He also has a reverse-engineered PAL equation
set for the CSR decode PAL (which is a pretty simple combinatorial
decode circuit), but the rest of the PALs (on the CQD-220, at least)
are probably somewhat more complicated. I'm willing to bet that they
have the security fuses blown, as well, but I haven't checked.
I have a second card that was injured in a horrible
accident (I plugged
it into the Unibus, justified the wrong way... so, it was off by two in
all the edge connectors. This promptly fried the card because the +20V
core voltage ended up in all the wrong places. That was the quickest
$300 I ever burned. It was however, educational.
I've since repaired most of the damage, replacing buffers, burned traces,
etc. however a couple PALs were affected and need to be replaced.
I am chicken to take them from my working board and try to read them
out unless there's a high likelihood it can be done.
You might have some luck replicating them if you can find (or make) a
schematic, because most of their functions should be pretty apparent
from that. It takes an awfully long time to trace out
a board like
that, though, especially with components still on (and if it's
like
the CQD-220, it's a four-layer board with at least some of the signal
traces buried in inner layers).
Or, if they've already been read, then I could
just burn new ones from
the images and try them.
I'd be thrilled if they were reverse-engineered, or if someone can
persuade CMD (now owned by Silicon Image) to release the materials
needed to repair vintage hardware.
- Dave