4 Jul
1999
4 Jul
'99
9:21 a.m.
plz see embedded comments below.
Dick
-----Original Message-----
From: Tony Duell <ard(a)p850ug1.demon.co.uk>
To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
Date: Sunday, July 04, 1999 2:01 PM
Subject: Re: OT: A call to arms (sort of)
Oddly enough, the DRV11-WA was the one board for which I saw reasonable
documentation, and it was what we used to interface to the E3-A (AWACS). I
saw no PAL equations, and, in fact, the PALs were soldered in place, so if
there were any, which I don't remember, you couldn't read them even if there
were no security bit.
I
guess I just had too little interest in DEC to notice that. Documentation
was an issue, though, and as I once mentioned, even DEC couldn't tell if two
of their machines were alike.
>
> <This is where I'd recommend caution if you use q-bus. The schematics
must
> <not only be available and complete, but they
must be correct as well.
PAL
<must be
fully characterized, something I've never seen in a DEC product,
A lot of the time, DEC didn't copy-protect the PALs on their Unibus or
Q-bus cards. So it is possible to get the equations out of them. That,
combined with the schematic is enough.
I have seen some DEC printests with logic equations in them. I've also
seen one (DRV11-W?) with the PALs drawn out as gates.
Sorry, no. DEC in the handbooks provide full
data, timing, and sample
schematics for qbus interfaces. Same for Omnibus Unibus. In that area
Indeed. The PDP11 bus handbook is a very useful document.
There is a standard, however. IBM didn't create it.
interface (DMA capable) already there. ISA, I
don't have any similar
concise reference for bus timing other than a few simple published
circuits. I've ahd to extrapolate from the XT and 8088 (and supporting
chips) knowledge to get things like timing and protocal for at least the
ISA 8bit.
No, the IBM Techrefs do _NOT_ include timing diagrams, etc for the ISA
bus. Sure you can work them out from the 8088 data sheets, etc, but the
fact is, IBM did not fully document ISA.
-tony