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From: smc8516@isc.rit.edu (S.M. Curtin)
Newsgroups: comp.sys.amiga.hardware
Subject: 68030 In a Lucas and MMU stuff
Message-ID: <1990Dec17.204644.22516@isc.rit.edu>
Date: 17 Dec 90 20:46:44 GMT
Reply-To: smc8516@ultb.rit.edu.isc.rit.edu (S.M. Curtin)
Organization: Rochester Institute of Technology
Lines: 41


I posted this last week and got no replies or acknowledgement
whatsoever, so I'm assuming our server screwed up again. Below are some
questions I'd really like to know the answers to.



A friend and I are planning to build LUCAS boards for ourselves within
the next few months. I seem to remember reading here that one could
replace the 68020 in a LUCAS with a 68030 providing he rewires the
socket (and changes it?) and ties off the extra 68030 lines. Is my
memory correct on this matter. If so, could someone please repost or
point me in the direction of the pertinent information.

Also, would the MMU in the 68030 be operable in this type of setup. It's
the main reason I'm interested in using a 68030. If it's not going to
work, I might as well stick with an '020. Which leads me to another
question: how difficult would it be to install a 68851 on the lucas
board? If it's just a matter of a straight hookup like the 68881, I can
deal with it, if not I'd probably need a vivid description of how it's
done. (Do the 68851 docs give an example of this?) Which leads me to
ANOTHER question: Can the 68851 be hooked up to a 68010 (my current
processor) with ease, and if so would something like SetCpu be able to
detect and make use of it, despite the fact that an '020 or '030 is not
present in the system?

Anyone who has read my posts in the past here knows it's sort of an
ongoing quest of mine ever since I "upgraded" from a 1000 to a 500 to
achieve loadable kickstart on my machine. SetCpu offers that option, but
I need the MMU. If I don't do it this way, I'd have to Do SOme
cumbersome ram hack that maps memory atop and switches out the $f80000
ROM. I'd much rather go the more elegant route. Any help would be
appreciated. 

Thanks.

..Sean.

Oh, by the way, I AM the one who asked about readdressing 501 ram at WOC
in Toronto. I think those Q & A sessions are great. I hope you folks at
Commodore keep them up.