Re: IIc+ overclocking

[bieling@terra.es (Jorge Chamorro Bieling)]

Mark Frischknecht <appleiiguy@gmail.com> wrote:

> If you are gonna just over clock and not change the cache size all you
> need to do is replace the Osc. But to be safe I replaced the SRAM with
> faster versions.

Hmm... you say change the cache size ? 
I'm not sure that you can do this easily ?

If the address line a13 is connected to the memory socket, it would have
to be at pin 26 and that is cs2 in the 6264 (a 16k 62128 would need it
there). If you go with a 62256, then a14 goes to pin 1 that is a no
connection in the 6264 (and this is good).

But, if these signals were being feeded right now to the memory socket,
(and we forget that a13 is a chip select in the 6264) then I think the
cache "subsystem" would be badly misbehaving as it would be "rolling
over" every 8kb which is not good..

Please take a look at the pdfs of these memories, I have "saved" them
here:
<http://homepage.mac.com/jorgechamorro/a2things/>

And tell me if you think I'm right.

I see your new memories are 100ns parts. What was the speed of the
memories that you pulled ?

I'd like to speed the cpu to 14MHz, but I dont think that the asic that
controls this cache stuff will support it, that's almost a x4 overclock!

BYW, you should have put a socket to the oscillator...

Thanks Mark,
-- 
Jorge Chamorro Bieling