No more secrets Part B: Is it zero?
This module checks if the result of a computation is zero or not. The output of the circuit is one if all its input lines are zero. Viceversa, if one of its input has value one, the output is zero.
It is an implementation of a four inputs NOR gate.
This is the circuit:
and this is the map for jumpers:
i0 -> AA i1 -> BB i2 -> EE i3 -> FF A -> C B -> C C -> DD D -> I E -> G F -> G G -> HH H -> I I -> outnotZ JJ J -> outZ
notZ output is just for testing. When a led is connected to this line the entire circuit is a four inputs OR gate, so the led turns on when at least one of the input line is one. outZ is the result of a NOR gate so it has the opposite behavior: a led diode connected to outZ lits when all the inputs are zero and it get turned off as soon as at least one input has the value one.