Question

If I have a 5-variable function (below) and I want to implement it using a multiplexer, how would I do that (using the minimum possible multiplexer):

f(A,B,C,D,E) = A + C'D + BD' + B'D + B'CE

This is homework, so don’t provide a solution, just a guidance of how that works.

Thanks!

Answer 1

5 variables means a 2**5 (32) input multiplexer, with inputs 0 through 31. Convert the terms into binary numbers and hold the corresponding inputs high. For B'CE we have:

A B C D E
X 0 1 X 1

This gives us 4 numbers, since we have 2 don’t cares. The four numbers are:

00101 = 5
00111 = 7
10101 = 21
10111 = 23

Hold inputs 5, 7, 21, and 23 high.

Repeat for the rest of the terms.