Re: gEDA-user: m32c expansion board works!

[DJ Delorie <dj@xxxxxxxxxxx>]

I added some pictures of the board swamped with logic probe clips (22
clips) as I debugged the bus timing.

http://www.delorie.com/pcb/m3a/

Turns out the CP2200 is too slow to run the m32c at full speed (30
MHz); the m32c can only add 3 wait states (115nS vs 140nS needed).
The RAM is too slow for zero wait states by design (15nS vs 20nS
needed); the rd/wr pulses are only a half clock wide, not a full
clock.

So, I programmed the m32c to run at half the crystal speed (15MHz),
the RAM at 0 ws (33nS) and the cp2200 at 2 ws (165nS).  It seems to be
happy that way.


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