Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!wuarchive!psuvax1!rutgers!cbmvax!daveh
From: daveh@cbmvax.commodore.com (Dave Haynie)
Newsgroups: comp.sys.amiga.misc
Subject: Re: Revised Amiga line
Message-ID: <21457@cbmvax.commodore.com>
Date: 9 May 91 23:06:28 GMT
References: <4822@orbit.cts.com>
Reply-To: daveh@cbmvax.commodore.com (Dave Haynie)
Organization: Commodore, West Chester, PA
Lines: 48

In article <4822@orbit.cts.com> chucks@pnet51.orb.mn.org (Erik Funkenbusch) writes:
>daveh@cbmvax.commodore.com (Dave Haynie) writes:
>>Well, keep in mind that what everyone thinks of as VLSI generally isn't.  

>Well, i was considering reducing the chip count.  such as integrating th
>8520's and other support chips into a single chip.  

That certainly COULD be done.  I suppose the only reason it hasn't is that
8520s, for example, have been made practically forever.  The 6526 used on the
C64 is practically the same chip.  So they're as cheap as sand, and while
any larger package could save you a little in board space (might just fit in
a 68 pin PLCC, I haven't checked), but cost you more in chip carrier and socket
money.

>heck, i know this is stretching it, but Apple shrunk the entire motherboard of
>the Apple IIe onto one chip (the Mega II chip) and the technology isn't much 
>less than that of the support circuitry on the 500.  

Keep in mind that the Apple II was, originally, pure TTL.  The video display
was thirtysomething TTL chips.  That's a trivial number of gates and also a
trivial number of I/O pins on a gate array, most of the logic involves
interconnection.  Most of the A500 "glue" left is buffer chips and that kind
of thing.  You don't substantially save going to a custom chip vs. off the
shelf TTL if you still need the same number of pins, unless that's real 
expensive TTL.  Or unless you can make it up in PC board savings, which is
certainly a possibility.

>That was the point.  shrinking the PCB to a very small size.  as for the 3000
>style backplane on a 2000, my point there was that if it could be designed to
>place all the expansion circuitry possible on the backplane, and also make it
>possible for the machine to function properly without the backplane then the
>redesigned 2000 could be sold much cheaper.

Sure.  Yeah, it could be done, and the price you pay would be one slot.  This
is essentially what Apple has done in their 20MHz 68030 machine, the IIsi.
You have Yet Another New Slot, which is probably more like the A500's 
expansion edge (albeit 32 bits wide) than anything else.  Your choice of
modules, one gives you NuBus, the other, their PD slot.  Of course, NuBus
costs substantially more than Zorro II to implement -- bus controller, buffers,
connector all cost more.  And they have the problem of supporting two mutually
exclusive slot "standards" in a machine with only one slot.  So while it could
be done, I don't know if it would save enough to make a difference.


-- 
Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests"
   {uunet|pyramid|rutgers}!cbmvax!daveh      PLINK: hazy     BIX: hazy
      "That's me in the corner, that's me in the spotlight" -R.E.M.