Multiplexers for general-purpose logic

• A 2n:1 mux can implement any function of n variables

  • Called a lookup table

• A 2n – 1:1 mux also can implement any function of n variables

  • Example: F(A,B,C) = m0 + m2 + m6 + m7 = A'B'(C') + A'B(C') + AB'(0) + AB(1)

A B C F0 0 0 10 0 1 00 1 0 10 1 1 01 0 0 01 0 1 01 1 0 11 1 1 1

C'C'01

S1

S0

F

0123

4:1 MUX

C'C'01

01234567

10100011

S2

8:1 MUX

S1

S0

F

A B C

A B

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