>> Those IDE boards are in fact a very simple boards.
I agree! On paper, at least. But all the chatter I've seen here w.r.t. the flavor of 8255, mods. to the boards, and subs. for some of the standard LS logic, leads me to believe that they are not all that straightforward.
>> Using a simple logic probe determine if the chip CS* lines is going low with a write.
It is.
>> If WR* is going low etc.
It is. Everything looks OK (with a simple logic probe), but I can't see these signals in relationship to each other (no digital logic analyzer).
>> Single step through a simple continuous write loop in RAM. Eg:-
Yep, did that. As I said, a simple loop to read from any of the 8255 ports seems to work OK. But, I can't see any output at any of the ports using a simple output loop. And, yes, I initialized the 8255 for input or output before running these loops.
>> By now there are well over 100 of these boards out there. It must be some glitch in your
>> system
That's what I can't understand -- my backplane (CompuPro) works fine with lots of legacy CPU's/FDCs/etc. N8VEM serial card works great in the backplane. I'm giving up on the CF cards for now ... can't spend any more time on this.
Roger