Finally I completely built and tested NEDONAND-16 board that is MPROM (Manually Programmable Read Only Memory ;)
It's programmable by inserting diodes into holes in proper places:
In order to do that diode's terminals must be specifically formed:
I connected it to my Analog Discovery 2 and tested its limits in terms of frequency:
So this is 100 kHz:
And this is 1 MHz - should be good enough for TTL:
P.S. But I redo this board anyway, because couple wires still may short on some copies of the board...
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Nice work !
Why did you use diodes ? wasn't simpler, cheaper and space saving to use dip switches ? Or it was a personnal achievement ?
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Thanks!
Switches will allow current to flow in both directions, but ROM in this circuit will work properly only if current flows only in one direction, so it has to be a diode, not wire
Are you sure? yes | no