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From: breemen@rulcvx.LeidenUniv.nl (E. van Breemen)
Newsgroups: comp.sys.amiga.hardware
Subject: Two problems with home-build '020 accelarator. Help needed.
Message-ID: <1991Jun19.192747.6888@rulway.LeidenUniv.nl>
Date: 19 Jun 91 19:27:47 GMT
Sender: root@rulway.LeidenUniv.nl (System PRIVILEGED Account)
Organization: Leiden University, the Netherlands.
Lines: 34
Nntp-Posting-Host: rulcvx.leidenuniv.nl


Leiden, The Netherlands, Wed Jun 19 20:07:10 1991

Today we finished our home-build 68020/68881 accelerator board for
the Amiga 500. It's a 14.3 MHz synchronous system, the successor 
of our 68000 14.3 MHz hack.  It's also possible to switch back
to the old 68000. Lot's of fun for just $125!
Everything worked fine (thanks Dave for your advice) the first
time we plugged it in.
All software that should work with a '020 works 100%.

However, we encountered two problems:

Problem I
SetCPU V1.6 locks up the machine completely. Maybe this is
caused when SetCPU executes a MMU instruction. Our board
only responds to FPU instructions, because it decodes the
FCx lines and A13 through A19. The '020 probably
never receives a *DSACKx and will wait forever...
Has anyone encountered this problem? Are there official 
guidelines that solve this kind of problems?

Problem II
The other problem occurs when booting a Promigos harddisk.
This hd starts up, but after a few startup-sequence commands,
it crashes (guru 4). Since all other software works great,
we suspect the hd-device driver software to cause the problem.
The Promigos harddisk is build around a 5527 OMTI controller.
We like to know if anyone else out there uses a Promigos harddisk
or another OMTI controlled harddisk with a '020 accelerator
without problems. All hints are very welcome, please e-mail!
Thanks in advance.

Greetings, Raymond Hoving en Erwin van Breemen.