Newsgroups: comp.sys.apple2
Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!wuarchive!m.cs.uiuc.edu!ernie!bazyar
From: bazyar@ernie (Jawaid Bazyar)
Subject: Re: ASIC Prototype
Message-ID: <1991Apr19.002759.28135@m.cs.uiuc.edu>
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Organization: Mutation Testing Facility, University of Illinois
References: <51671@apple.Apple.COM> <1991Apr18.190155.5198@m.cs.uiuc.edu> <109618@tut.cis.ohio-state.edu>
Date: Fri, 19 Apr 91 00:27:59 GMT
Lines: 46

In article <109618@tut.cis.ohio-state.edu> meekins@tortoise.cis.ohio-state.edu (timothy lee meekins) writes:
>Question:
>    "How are you running/using the ASIC?"

   It's just plugged into my motherboard right now, 2.8MHz. I'm basically
just testing it.

>Can you physically replace the Apple's 65816 and crystal or do you need
>a TWGS or ZIP?

  You can't speed up the motherboard without an accelerator.  Apple engineers
have stated, however, that by making a few simple changes to take advantage
of the ASICs page-mode RAM addressing, that they can up the motherboard to
8MHz with no problem. 

>Does the ASIC have different power consumptions than WDC/GTE chips? To use
>a chip >10 Mhz typically needs a larger power supply. Can I assume the ASIC
>is low power?

  I let it run all afternoon while I was gone. I came back and it wasn't
warm to the touch, which indicates it's power consumption is pretty low
(it is CMOS, after all).  Considering that certain ROM 03 power supplies
failed because the system didn't draw enough current from them, there
should be no problem.

>I guess what I am asking is: What does someone need to use the ASIC assuming
>it actually becomes available this decade?

  Obviously to get any benefit from it some sort of accelerator card is
necessary.  I'll test it first on a Transwarp, then depending on how it
works I'll buy a Zip (sorry, Albert) and crank away.
  FYI, I called Zip and they said that their computer simulations say that
the Zip card should work up to 20MHz.  They can't say for sure because they've
never had a processor to test it with. Oh, and get this:  They took a Zip and
and hopped it up to 14MHz (the whole power supply, etc shebang). Then they
did all the same mods to a Transwarp and could only get 11MHz out of it.
Meaning the Zip is a whole lot more robust (nothing I didn't already know).

  I'm going to be really careful about what I say from now on, so don't
expect too much, folks.

--
Jawaid Bazyar               |  "Twenty seven faces- with their eyes turned to
Senior/Computer Engineering |    the sky. I have got a camera, and an airtight
bazyar@cs.uiuc.edu          |     alibi.."
   Apple II Forever!        |  I need a job... Be priviliged to pay me! :-)