I'm studying for my exam in digital electronics in mid april. There is a question with a multiplexer where I should write the correct truth table but I don't understand how to do it. It should be written with 1:s and 0:s. Can someone explain how to do this?
You have 4 inputs A,B,C and D and you're looking for the output F(A,B,C,D). s0,s1,s2 decide which of the 8 inputs is mapped to the output. As we already know the the input values (0,1, D or ¬D) we can write the output function F(A,B,C,D).
F(A,B,C,D) = ¬A¬B¬CD + ¬A¬BC0 + ¬AB¬C¬D + ¬ABC0 + A¬B¬C1 + A¬BC¬D + AB¬CD + ABC0 F(A,B,C,D) = ¬A¬B¬CD + ¬AB¬C¬D + A¬B¬C + A¬BC¬D + AB¬CD
Then you create a table with all possible combinations of A,B,C and D and enter the resulting Y = F(A,B,C,D)
A B C D | Y 0 0 0 0 | 0 0 0 0 1 | 1 0 0 1 0 | 0 0 0 1 1 | 0 0 1 0 0 | 1 0 1 0 1 | 0 ...
I hope I didn't make any mistakes.