Re: Z80 CPU board - D2/D3 port timing problem

[Philippe Elie <philip...@gmail.com>]

Hi folks, quick update after having replaced the chips by F series : the board now appears to run fine in partial match mode up to 6 MHz. With a 8 MHz oscillator, the board hangs when loading CP/M but this is certainly the limit of my passive backplane. I have soldered three connectors on the 8 slot active backplane PCB I already have, I will populate it with the necessary components and run a quick test, until I get the terminator board or the 18-slot active backplane.

One problem to investigate though : Querying unused IO ports from the monitor still returns values different from FF, so certainly something's wrong somewhere...