PPT Slide

3 – Combinational Logic Implementation

© 1996 Gaetano Borriello

PALs and PLAs: design example (cont'd)

• Code converter: programmed PLA

50

not a particularly good

candidate for PAL/PLA

implementation since no terms are shared among outputs

however, much more compact and regular implementation when compared with discrete AND and OR gates

A B C D

W X Y Z

A

BD

BC

BC'

B

C

A'B'C'D

BCD

AD'

BCD'

minimized functions:

W = A + B D + B C

X = B C'

Y = B + C

Z = A'B'C'D + B C D + A D' + B' C D'

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