Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!wuarchive!psuvax1!rutgers!cbmvax!valentin
From: valentin@cbmvax.commodore.com (Valentin Pepelea)
Newsgroups: comp.sys.amiga.hardware
Subject: Re: Cramming an 030 into an 020 hole
Message-ID: <9813@cbmvax.commodore.com>
Date: 24 Feb 90 08:49:11 GMT
References: <86.25e424b2@intersil.uucp>
Reply-To: valentin@cbmvax.cbm.commodore.com (Valentin Pepelea)
Organization: Commodore, West Chester, PA
Lines: 31

In article <86.25e424b2@intersil.uucp> hamilton@intersil.uucp (Fred Hamilton) writes:
>
> So I turned the data cache on and...it crashed.  In addition, it crashed
> when I ran AFM to add the Frances RAM to the system.  In all other respects,
> it seems to work great!  So my questions are:
>
>1)  Should I be able to turn on the data cache and have everything work OK,
>    or should it always be off when accessing chip ram because of DMA going
>    on?  Is that why it crashed?  How do other 030 boards deal with it?

Yes, that's what the problem was. The A2630 board disables the cache
automatically through hardware (MMUDIS pin) when chip and I/O memory is
accessed.

You have to do the same thing, but through software. Take the source code
to Dave Haynie's Setcpu, and in the translation tables, set the CI bit
(cache inhibit) for all the page descriptors that map the chip ram area
and the hardware registers area. 

> 2)  Any ideas why I can't add my 32 bit Frances RAM to the system?

I don't know what the AFM program is and does. (and how it does it) Send
me a Lucas board, and I'll solve these problems for you. (I already have
a 68030 to 68020 widget)

Valentin  :-)
-- 
The Goddess of democracy? "The tyrants     Name:    Valentin Pepelea
may distroy a statue,  but they cannot     Phone:   (215) 431-9327
kill a god."                               UseNet:  cbmvax!valentin@uunet.uu.net
             - Ancient Chinese Proverb     Claimer: I not Commodore spokesman be