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From: welland@cbmvax.UUCP (Bob Welland)
Newsgroups: comp.sys.amiga
Subject: Re: New Custom Chips?
Message-ID: <2376@cbmvax.UUCP>
Date: Mon, 21-Sep-87 17:44:23 EDT
Article-I.D.: cbmvax.2376
Posted: Mon Sep 21 17:44:23 1987
Date-Received: Wed, 23-Sep-87 01:19:26 EDT
References: <2948@hoptoad.uucp> <2345@cbmvax.UUCP> <2472@xanth.UUCP> <3823@zen.berkeley.edu>
Reply-To: welland@cbmvax.UUCP (Bob Welland)
Organization: Commodore Technology, West Chester, PA
Lines: 26


The idea of making a Fat Agnus to Agnus converter is a rather tricky
one. I would advise anyone thinking about this to think instead about
a Fat Agnus and Gary conversion. These two chips work very closely in
consort with each other and it would take a lot of logic (and hacking)
to make a TTL version work. Another problem is that Fat Agnus generates
all of the clocks for the system. This replaces a mess of logic on the
A1000. This means that all of the A1000 clock logic has to be bypassed.
It would be much easier to replace ALL of the logic on the A1000 except
the custom chips, the 8520's, and the 68000. It would make for a strange
tower board but it might work ...

If you look at an A500 you will see that there is very little other then
the the chips mentioned above ... everything else has been squeezed into
Fat Agnus, Gary, and the Video Hybrid (which you do not need).

Finally if one wanted to make life even easier you could dump the
writable control store and replace it by the ROM ... (I can hear the
booing and hissing allready)


				Bob Welland


All of the words seen above are my own ... not those of my esteemed
corporation.