Quote:
Originally Posted by SiriusHardware
Looked again more closely and found that my logic probe was actually seeing short _CE pulses (TTL mode : Pulse mode 'on') and only when stepping through the address range 0200-07FF. Outside that range, no CE pulses. And yet still no memory operation.
I've just found the reason why, my NRDS and NWDS pickup wires are crossed. Too tired to drag the soldering iron out to sort it tonight, I'll do it tomorrow and report back.
Funnily enough Ian, it was the unintentional RD / WD 'twist' on your diagram in #45 which prompted me to check that, so thanks!  |
Strangely enough that crossed my mind but I thought "nah, thatd be too weird if we both made the same mistake....!"