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orangeincup
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Homework Statement
The question is mostly in the picture, it has tables associated with it so I couldn't put it here.QUESTION: Make a truth table of the controller outputs enable/direction, as a function of the inputs S1, S2, R1, and R2. Since you have not been given the explicit output for some inputs, to minimize the number of gates in the circuit, it is desirable to mark these outputs as “don’t care”, denoted by “X” and meaning that either a 0 or 1 is acceptable.
Homework Equations
The Attempt at a Solution
I'm a bit confused at the question,
should my truth table be something like..
S1 | S2 | R1 | R2| Enable Direction
0 0 0 0 X X
0 0 0 1 ? ?
0 0 1 1 ? ?
0 1 1 1 1 0
...
1 1 11 0 X
I have an input for (R1 R2 ) 0 1, but no input for S1 and S2. Should I put X X again or am I doing this wrong? If either side has no input(aka 0 0) should I put X X for both enable and direction?
For the next part, 0 1 1 1... should it be 1 0? Meaning I am on second floor, and want to go to ground floor. I want it to move down two floors, but the direction command only says go down 1 floor for the 0 input.
For 1 1 1 1... should it be 0 X? I want the door to open but direction doesn't have to do anything.