Path: news.weeg.uiowa.edu!news.uiowa.edu!hobbes.physics.uiowa.edu!math.ohio-state.edu!howland.reston.ans.net!pipex!uknet!EU.net!Germany.EU.net!netmbx.de!zib-berlin.de!fauern!lrz-muenchen.de!colin.muc.de!meadow.muc.de!schaf Date: 16 May 1994 05:22:00 +0100 From: schaf@meadow.muc.de (Soenke Behrens) Newsgroups: comp.sys.apple2 Message-ID: <5OxOvdOEzhB@meadow.muc.de> References: Subject: Re: Could it be done? X-Newsreader: XP v3.02 Lines: 30 > Could more RAM be added to a ROM01 or ROM03 GS in the sound RAM space? > I know it wouldn't be feasible, too expensive, you don't like RAM, etc. > But could it be done, and if so, how? It could be done. Solder another 64k on top of the existing 64k. Address and data lines are shared, chip enable lines not. Now, for chip enable: - Look at what the DOC outputs, use that for DOC access. - Use a gameport softswitch or whatever to have something so the GS can write into the upper 64k. Whenever it's on, select upper 64k for writing. Of course, you would have to be sure not to confuse DOC accesses and GS accesses. So, some TTLs (or a GAL) would be in order. I'm too lazy to look up all the names of the lines you need, but it's all there in the GS Hardware Ref., really. By looking at the circuitry and the names of them you can figure it out quickly. Can be done, software won't support it "out of the box", is a real hacker solution. I don't think it's really worth it. Nice idea, though. Oh, while you're at it and fiddle with the gameport: Install a cable for the second joystick, too ;-). Soenke -- Decompression sucksssss ## CrossPoint v3.02 ##