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Re: 65c02 in Apple][



Robert Steinmetz wrote:

Vince Briel wrote:

The real reason for this is to use a CFFA card in this machine,
which requires  65c02 but its not working correctly (yet)



I've worked with Rich Dreher on that problem for a while and I've also installed a Rockwell 65C02 in my IIplus with weird results. It seems to work for a few seconds then looses the ability to do prodos commands. I've read old articles relating to issues with a 65C02 in a IIplus and the problem appears to be a memory timing issue. It may be possible to replace the 74LS257's at locations B6 and B7 on the main board with a faster version like a HCT series. I haven't tried this yet but I plan to within the next couple of
weeks.

Vince

--
Replica I
The Apple I clone

http://www.applefritter.com/apple1/members/replica1/index.htm


Yes, the results I'm getting seem sort of consistently, inconsistent.

I also tried a Zip Chip, with almost the same results.

Sorry for replying to my own post.

I forgot to mention I have been able to boot Prodos 2.0.x from a Disk][ in my Apple][ with the 65c02 installed.

I think possibly the problem may lie in timing issues related to the CFFA not just the Apple ][.

Please keep us posted on your progress.

--
Rob

"Never ascribe to malice that which can adequately be explained by stupidity."