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. _______________________________________________ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user