=== uIDE-8 74LS02 considerations ===
The timing of the Z80 /RD signal is very tight, so the choice of NOR gate IC that you put at U2 is critical. Choose a fast part such as a 74'''F'''02. At least one manufacturer, Misubishi, makes a fast enough 74'''LS'''02 and that is what I used in my prototype. It has a propagation delay of 6-12ns15ns, and this the typical delay is somewhere in between, say 9ns. This appears to be the maximum lowest speed the design will allow, although I have only tested with a few '02 variants. If in doubt, check the manufacturer's datasheetand don't buy anything with an average propagation delay larger than say 9ns. I've done this listed the delay times for several different '02 logic chips and below. It's quite surprising what the results propagation time range is for parts that are belowsupposedly "standard".
'''74??02 Propagation times'''
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If in doubt, ask on the forum or choose a '''74F02''' or known working typeshown above. If you find working types that are not listed, or are shown as not compatible, please let me know so I can update the list. As a result of this investigation, the BOM was updates to specify a 74F02 for U2.
== Pictures of the built boards ==