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Re: IIc+ overclocking



Jorge Chamorro Bieling wrote:
> 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,

	I Did put a socket in. And my SRAM is now 70 ns. The Sram chips are
HY6264LP-70 (8k by 8 bit CMOS SRAM's)

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