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Re: Z80 its refresh pin

David Wilson wrote:

On Mar 29, 12:52 am, srk...@gmail.com wrote:


2. SoftCard has to use a very special clocking scheme to be able to
access the Apple's memory transparently. It pulses twice during PH0 and
stays low during PH1. Well documented.

I think i might have this bit ok. An image of the captured FPGA wave
form shows it seems to look the part;

http://users.tpg.com.au/srkh//PH0%2BPH1%2BPIN6.png


Unless my eyes deceive me, you have the double pulse during PH1 rather
than PH0.



This is correct. I wrote from (bad) memory. PH1 is the CPU access time.

-Alex.