# Design logic circut

Discussion in 'Homework Help' started by katarina, Apr 15, 2013.

1. ### katarina Thread Starter New Member

Apr 15, 2013
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"In this exercise you have to make a combinatorial digital circuit. The circuit has a bit width of 2 bit. The circuit also has two control signals A and B which decide the function of the circuit according to TABLE 1(attachement). The signals in and out are on 2's complement form."

I am completely lost on where to start here. First of all the table makes no sense to me, what does "Out = In" actually mean, and "Out = In-1" etc. perhaps that can give me some kind of clue on where to start. I read up on the basics of logic circuits and know what an AND, OR, NOT, NAND, NOR and XOR gate is, but I am not sure how all that helps me solve this exercise.

Thank you all!

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2. ### absf AAC Fanatic!

Dec 29, 2010
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You have to design the inside of the black box as attached so that:

When func_A=0,
and func_B=1,
If input="11", output should be="10" (Out = In -1).

Allen

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3. ### katarina Thread Starter New Member

Apr 15, 2013
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Thank you! That made it way more clear, I am going to try to continue further from here on and see how far I get