Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!uunet!mcsun!unido!mpirbn!p554mve
From: p554mve@mpirbn.UUCP (Michael van Elst)
Newsgroups: comp.sys.amiga
Subject: Re: A-501 2 meg autoconfig?
Keywords: Autoconfig 501 Amiga 500
Message-ID: <562@mpirbn.UUCP>
Date: 21 Feb 90 14:44:08 GMT
References: <1251@crash.cts.com> <9442@cbmvax.commodore.com> <1277@bmers58.UUCP> <1287@bmers58.UUCP> <9696@cbmvax.commodore.com> <-1773786386@convex.convex.com> <9731@cbmvax.commodore.com> <3308@pikes.Colorado.EDU>
Reply-To: p554mve@mpirbn.UUCP (Michael van Elst)
Organization: Max-Planck-Institut fuer Radioastronomie, Bonn
Lines: 17

In article <3308@pikes.Colorado.EDU> bscott@pikes.Colorado.EDU (Ben M Scott) writes:
>I've seen stuff about 1.8 and 2 meg expanders that fit in the Amiga 500's
>A-501 slot.  Obviously, you'll need some connection to the motherboard (I'd
>guess the Gary, since it's close) for the extra address lines.  However, I've
>been asking hither and yon whether these cards are autoconfig;

That's indeed possible (and done). Those expanders replace the orignal
512k ram expansion. The additional memory is placed in the so called
"ranger" memory space starting at address $c00000 (and of course as
additional CHIP RAM at $080000 if you have a big agnus). 
Exec checks up to 1.8 meg, the following addresses are dedicated to
the battery backed clock and the custom chip registers.

Since this is on the chip memory bus its only "slow"-fast memory.

Michael van Elst
uunet!unido!mpirbn!p554mve