hunt@tramp.Colorado.EDU (Lee Cameron Hunt) (09/02/89)
I have received quite a few requests for this and I could not
respond to many of them do to a braindamaged mailer. So, here it
is:
>From daveh@cbmvax.commodore.com Mon Aug 28 08:52:47 1989
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Date: Mon, 28 Aug 89 10:32:54 EDT
From: daveh@cbmvax.commodore.com (Dave Haynie)
Message-Id: <8908281432.AA16312@cbmvax.UUCP>
To: ncar!boulder!spot!maziar@spot
Subject: Rev 6
Status: R
Commodore is aware of the conflict between the Rev 6 board and the
Microbotics hardframe, and we (George Robbins, !cbmvax!grr) are investigating
the conflict. I'm not personally involved in this investigation.
In any case, what I can tell you:
- The Rev 6 timing is identical to the Rev 4.x timing. All the same parts
are used.
- The pullup fix you're talking about was something officially sanctioned
by Commodore to bus a potentially troublesome situation in which BAS*
could take too long to rise. This problem was corrected in production
starting at Rev 4.5, and it's of course on Rev 6. I really wouldn't
recommend an additional 1k pullup there.
- The problem you heard of an earlier "timing problem" on older 2000s seems
to have been exaggerated quite a bit. The original 2000s were shipped in
conjunction with a keyboard made by Cherry in West Germany. These keyboards
had very strong output drivers which caused lots of noise, and to pass the
FCC tests, our FCC engineers had placed an extra set of bypass capacitors
on the keyboard lines. When production switched over to the more common
(these day) HiTek keyboard (which is very similar internally to the
A1000 keyboard design), these capacitors were no longer necessary, but they
didn't immediately get the word to remove them in production. The HiTek
keyboard used different drivers that were occasionally marginal with these
extra capacitors. Generally, the CIA that reads the keyboard would get
confused on powerup and the first keystroke in a CLI window could be
missed. This didn't effect mouse operation at all, and in most cases, the
missed first keystroke was the extent of the problem. That was fixed long
ago in production.
Anyway, the Rev 6 investigation is underway, and as usual, if it's Commodore's
fault, you get a free fix, even if your warrenty is out (that's what they
tell me, and I agree with the policy). Far as we know, the only conflict
has been with the Microbotics design, but they probably do push the bus as
fast or faster than anyone out there, so if it is a Rev 6 problem and not
theirs, we'll certainly find out.
Dave Haynie Commodore-Amiga (Systems Engineering) "The Crew That Never Rests"
{uunet|pyramid|rutgers}!cbmvax!daveh PLINK: hazy BIX: hazy
We have no choice. We are, after all, professionals.
A side note: In moving from my appartment to to another residence I put
the cover back on my 2000 (I had already installed the omnious 1K pullup
resistor between pins 11 and 20 of U605). It had not been working
reliably with that setup (but it was working better, at least I
could format the drive). Anyhow, with the cover on it has been working
fine! (and I don't know at all why... perhaps it's cooler).
--Lee
(...!ncar!boulder!spot!tramp!hunt)