Confirmed that they all have the same shape and do not overlap with each other.
Colin.
Quote:
Originally Posted by SiriusHardware
They certainly look like chip select pulses so it would seem that even in its semi disabled state the system is managing to sweep through the address ranges of the PROMs. Just one other thing to try while you are in the area: Scope any two of the PROM pin 20s at the same time. You should see that they are selected at the same rate / frequency but at different times, so the chip select pulses will be staggered, one before the other, showing that only one PROM is selected at a time. If any chip select pulses are directly one above the other that would show two devices being selected at the same time (which should not happen).
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