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RE: [N8VEM-S100:5667] Re: Z80 CPU board - D2/D3 port timing problem

Philippe I’m surprised you are getting away with only one wait state, I seem to remember I have 2 or3 for 10 MHz. If people have problems at these speeds may want to play around with wait states, particular for I/O.




From: n8vem...@googlegroups.com [mailto:n8vem...@googlegroups.com] On Behalf Of Philippe Elie
Sent: Sunday, November 23, 2014 4:21 AM
To: n8vem...@googlegroups.com
Subject: [N8VEM-S100:5667] Re: Z80 CPU board - D2/D3 port timing problem


Hi folks,

a quick update in case this can be of interest to others : even after the above modifications, I ran a infinite test loop (a turbo pascal program incrementing an integer and displaying the result) and discovered the display was hanging after around one hour.

I ran a RAM test with no IOs that worked perfectly well. I started to suspect the console IO timing, and indeed that was the issue : i swapped the 244, 32, 04 and 00's for F versions, and the turbo pascal loop is not running since more than 3 hours. 

note than i use one one wait state for IO, RAM and ROM with a 10 MHz oscillator.


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