Digital Logic & Design Dr. Waseem Ikram Lecture No. 16

Recap

Carry Propagation Delay between 4-bit ALU units

Carry Propagation Delay eliminated by using Group Carry

16-bit ALU S0 S1 S2 Cin G P P0 74X381 A2 B2 A3 B3 ALU0 A0 B0 A1 B1 F0

Parallel Comparators

Implementation of A>B

Implementation of A=B

Implementation of A<B

Comparison of numbers by Cascaded 4-bit Comparator Comparator M Comparator L 1101 0111 A>B 0110 1011 A<B 0011 0010 A=B 0100 0101 1001

Implementation of 4-bit Comparator by Cascading two 2-bit Comparators

Iterative Circuit Implementation of A=B function

Iterative Circuit Implementation of A>B function

12-bit Comparator

Electronic Door Lock

Function Table of a 2-to-4 Binary Decoder Input Output I1 I0 O0 O1 O2 O3 1

2-to-4 Decoder

Function Table of 74LS139, 2-to-4 Decoder Input Output B A 1 X

74LS139, 2-to-4 Decoder

Decoders