Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!apple!sun-barr!newstop!sun!imagen!atari!apratt
From: apratt@atari.UUCP (Allan Pratt)
Newsgroups: comp.sys.atari.st.tech
Subject: Re: TT VME Bus
Keywords: VME Bus, TT
Message-ID: <2947@atari.UUCP>
Date: 20 May 91 17:11:08 GMT
References: <1991May16.065921.26031@ux1.cso.uiuc.edu> <1991May16.163752.24994@daffy.cs.wisc.edu> <17302@chaph.usc.edu>
Organization: Atari Corp., Sunnyvale CA
Lines: 24

baffoni@aludra.usc.edu (Juxtaposer) writes:
>	Is it possible [to make]  an accelerator card that  uses
>the buslines available on the VME/Atari (TT/mega)bus slots?  Like for instance 
>a 68040 board that takes over the machine and delegates the on
>board cpu as an I/O handler ... ?

No, it's not, because the things that can go on the VME bus in the TT can't
be bus masters.  The TT's VME bus is slave-only, meaning the motherboard
can instigate an access to the VME board, but not the other way around. It
is not unreasonable to suppose that future Atari machines may have
full-blown VME where the VME boards can be bus masters, and then you could
do this.

>Dave Small has already shown that it's possible
>for the ST...:)

No, he shows that it's possible to wire a 68030 into the ST.  I don't know
how he tells the 68000 to go to sleep; maybe you have to cut the whole
thing loose, maybe you just have to cut a few traces (like power and
ground :-) to get it out of the circuit.

============================================
Opinions expressed above do not necessarily	-- Allan Pratt, Atari Corp.
reflect those of Atari Corp. or anyone else.	  ...ames!atari!apratt