Re: Could it be done?

[schaf@meadow.muc.de (Soenke Behrens)]

> 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
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