Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!cbmvax!daveh From: daveh@cbmvax.commodore.com (Dave Haynie) Newsgroups: comp.sys.amiga.tech Subject: Re: DAVE HAYNIE!!! Message-ID: <14198@cbmvax.commodore.com> Date: 4 Sep 90 23:14:50 GMT References: <4133@crash.cts.com> Reply-To: daveh@cbmvax (Dave Haynie) Organization: Commodore, West Chester, PA Lines: 47 In article <4133@crash.cts.com> hawk@pnet01.cts.com (John Anderson) writes: > Sorry Dave, I just wanted to make sure I flagged you down before you skipped >past this message. I'm still working on getting a 2 meg Agnus into a 2000. OK, fine, but you're going about it wrong. >My 1 meg agnus map the on-board 1 meg into chip RAM from 0 to 1 meg. Yes, and, ignoring other issues, you will have to have a similar additional 1 meg of Chip RAM to fill the second meg of Chip RAM space. How to get that memory there without getting too ugly will be your problem. >I have a 16 bit 2 meg RAM board and a 4 meg 2630 board. Neither of those will do you one bit of good as Chip RAM. Chip RAM in on the Agnus bus, neither of those memory chunks are addressable by Agnus. You have to find some way to tack another meg of memory onto the Chip bus, and then you'll have to rewire some memory decode logic to get the 2 Meg Agnus to address that memory, since it does things a little differently than 1 Meg or 512K Agnus. >What happened to the space from 1 meg to 2 meg ($100000 - $1fffff)? That memory space is on the Chip bus, but there's no simple way to put any additional memory there. >I don't necessarily want the second meg to be 32 bits wide, That's good, because it can't be 32 bits wide on an A2000, period. >How can I get the 16 bit expansion board (or the first 1 meg of it) mapped >right after the first meg of chip RAM? You can't. If you're into building your own memory board, or some similar thing, you can probably build a tower board, a thing that plugs into the 84 pin Agnus socket and contains the extra decoding logic and the second megabyte. Pretty ugly, though, and not a whole lot of room down there to put such a creation. -- Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests" {uunet|pyramid|rutgers}!cbmvax!daveh PLINK: hazy BIX: hazy Get that coffee outta my face, put a Margarita in its place!