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From: joost@neabbs.UUCP (JOOST BOERHOUT)
Newsgroups: comp.sys.amiga.hardware
Subject: 2.0 in FRANCES
Message-ID: <444299@neabbs.UUCP>
Date: 4 Sep 90 20:59:25 GMT
Organization: NEABBS multi-line BBS +31-20-5733533 (13x), Amsterdam, Holland.
Lines: 37

In msg 440507 news.amigahard 28-08-90 Fred Hamilton wrote:

 FH> The only problem is, FRANCES ram disappears betwen when you reset
 FH> the computer (control A-A) and when the resident AFM program is executed.
 FH>
 FH>  [ ... some stuff deleted ... ]
 FH>
 FH> So the only reason that you can have 1.3 in FRANCES ram is because
 FH> during re-boot the exact same image exists in the WCS/ROMs. So if we ever
 FH> want to have a chance of using this technique to run 2.0 (without 2.0 in
 FH> ROM from a Rejuevenator or the like), we'll have to figure out why the
 FH> 8421 DRAM controller seems to lose its programming and needs to be
 FH> modeloaded after every reset (*RESET only goes to the REMAPK flip-flop,
 FH> it doesn't go to the 8421).

I took a thorough look at the spec of the DP8421 DRAM controller and could
not find anything which matches the above described behaviour. There is no
way that the chip 'knows' that a reset cycle is going on. So what actually
happens during a reset of the 68020 ?  The only important thing I can
imagine is that the address bus will be tri-stated thus writing nonsence
to the chip !  This could be fixed with a pulldown resistor at A23 or A31.
I must admit that the above sounds silly but who knows (Murphy :-).

I myself have two problems with FRANCES:

 1) it needs a warming up of 3 - 5 minutes or so.
 2) AFM alway fails to find FRANCES the first time.

I can't explain why FRANCES needs the warming up except the darn thing
is working on the edge of the (timing) specs. A heated chip will have
a shift in the timing specs so this seems to be the case.
I have version 1.11a of the AFM program. This version does not wait for
the required 60ms initialization time of the DP8421 (I took a gimpse
of the source). This should explain why AFM always finds FRANCES the
second time it runs.
Are these two 'problems' known to anyone of you ? Please confirm.

- joost -