Re: Z80 CPU Speeds? - Upgrading

[mjmahon@aol.com (Michael J. Mahon)]

Roy wrote:

>Eric Smith wrote:
>> "Brian A. Davis" <badavis@nbnet.nb.ca> writes:
>> 
>>>Sorry, Roy. I was not specific enough. I have a PCPI Appli-card with a 6 
>>>MHz Z80B. On board the Appli-card is a 12 MHz oscillator. This is what I 
>>>was thinking of changing. I did not mean the oscillator on the Apple IIe 
>>>motherboard.
>>>
>>>The PCPI Appli-card has its own 64k RAM bank, so the only interactions 
>>>between the card and the Apple IIe motheboard are I/O calls (I think).
>> 
>> 
>> It *might* work.  But even if it seems to work, I wouldn't count on it
>> being reliable.  Running it faster than designed will probably result
>> in the memory timing being on (or over) the hairy edge.
>
>Faster memory chips might help, but I'd be more concerned with how the 
>card interfaces with the II. Since I have the same card, Brian, I'd be 
>glad to let you experiment with yours and let me know if it works, and 
>is safe for mine...   ;-)

The interface with the 6502 should be OK, since it's just a shared
register with software handshaking.

-michael

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