carter@cat27.cs.wisc.edu (Gregory Carter) (03/20/91)
Maybe I am just a naive dunce, but I thought I would have the option of
putting in my MEGA STE a nice cpu card someday, or even a nice graphics
card...So what?
Well, I gave the specifications of Atari's VME bus to a freind of mine to
see exactly what I could do and couldn't do and he comes up with the
following very depressing comments.
^^^^^^^^^^
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The fact that the slot is 3U is depressing, the bulk of the VME market is
in the 6U cards, so your options are going to be very limited. Looks to me
more like a way for atari to use a standard bus and allow some kind of
expansion. So you have one 96pin euro connector and about a 4 inch wide slot?
If you really wanted to use 6U cards, you could use the connector with some
kind of cable/extender arrangement to an external case which could
have perhaps multiple card slots. The statement that it is slave only pretty
much rules out CPU cards in the usual sense. Lack of bus arbitration means
you cannot use slave cards (like disk controllers) that want to do DMA
transfers.
This bus would be ideal for things like D/A and A/D converter cards.
PIO cards, communications cards (so long as they avoid DMA - ethernet notable
here). Graphics cards would be a possibility.
The power you quote is very limited (only 50MA of +-12 !! the 2A of +5 would
be just enough to power the single 3U card). If you set things up to an
external multislot box, you would definitely want an external and INDEPENDENT
power supply (and perhaps buffering for the signal lines -- but this would
introduce delays and skew ....).
Take all I say with a grain of salt. VITA (VMEbus intl trade assn or something
like that) publishes a yearly directory of VME products -- I used to have one
of these. Some other VME books are out as well.
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Maybe this is just one guys opinion. Maybe he is wrong?
I think I am going to cry....it won't be the last time either I have a feeling.
--Gregoryarcher@elysium.esd.sgi.com (Archer Sully) (03/20/91)
In <1991Mar19.201218.15050@daffy.cs.wisc.edu> carter@cat27.cs.wisc.edu (Gregory Carter) writes:
*
*Maybe this is just one guys opinion. Maybe he is wrong?
*
No, he's absolutely right.
--
"Actually, I'd rather play a nazi transsexual in a buddy film"
-- John Cusack
<archer@sgi.com> Archer Sully