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From: grr@cbmvax.UUCP (George Robbins)
Newsgroups: comp.sys.amiga
Subject: Re: Commodore 68020
Message-ID: <2788@cbmvax.UUCP>
Date: Mon, 16-Nov-87 03:31:57 EST
Article-I.D.: cbmvax.2788
Posted: Mon Nov 16 03:31:57 1987
Date-Received: Tue, 17-Nov-87 06:12:07 EST
References: <2720@cbmvax.UUCP> <5338@cisunx.UUCP>
Reply-To: grr@cbmvax.UUCP (George Robbins)
Distribution: na
Organization: Commodore Technology, West Chester, PA
Lines: 43

In article <5338@cisunx.UUCP> ejkst@cisunx.UUCP (Eric J. Kennedy) writes:
> In article <2720@cbmvax.UUCP>, welland@cbmvax.UUCP (Bob Welland) writes:
> > 
> > I was dissapointed to see that no one who was at the  COMDEX
> > show reported on the Commodore 68020 board for the A2000. It
> > was shown in the booth by Dave Haynie (he and  I  where  the
> > designers). It has some nice features !
> > 
> > RAM option      0, 1M, 2M       Numbers in bytes
> > RAM width       32 bits
> > RAM expansion   Yes
> > on-board?
> > RAM is          Yes
> > auto-config?
> > 
> Can this 32 bit memory be used along with 16 bit memory expansions?
> If so, how does it work?  I.e. what determines which type of memory
> is used if both types are available to the system.  

The memory will auto-config along with any memory on the expansion bus.  It
gets configured first, thus will most likely be at the 200000-3FFFFF spot.
AmigaDOS doesn't have any real preference for this memory, but one could
probably do some tuning by editing the memory list before starting ram-disks
and other low-priority items.
  
> Also, I seem to remember reading that CSA's Turbo-Amiga has a 12 Meg
> limit of 32 bit memory.  How does that work?  Just what are the limits
> with a 32 bit system?  

If the memory is placed outside the normal 16MB space, all you want.  However,
on the current 68020 board we chose to place the memory within the confines
of the normal expansion bus architecture, mostly so that DMA devices can
transfer data directly into the memory, without having to do a programmed
memory-to-memory transfer.

I'm not sure of the 12 MB limit on the CSA board, I'd guess it's some kind
of electrical or loading limit, since they only get a little memory on
each of their static RAM cards.

-- 
George Robbins - now working for,	uucp: {ihnp4|rutgers|allegra}!cbmvax!grr
but no way officially representing	arpa: out to lunch...
Commodore, Engineering Department	fone: 215-431-9255 (only by moonlite)