1. Overview Introduction Logic Gates Flip Flops Registers Counters
Review of Basics of Digital Electronics Lecture 3
Overview
Introduction
Logic Gates
Flip Flops
Registers
Counters
Multiplexer/ Demultiplexer
Decoder/ Encoder
CSE 211, Computer Organization and Architecture Harjeet Kaur, CSE/IT

2. Multiplexer/Demultiplexer
Review of Basics of Digital Electronics Lecture 3
Multiplexer/Demultiplexer
4-to-1 Multiplexer I0 I1 I2 I3 S0 S1 Y I0 I1 I2 I3
Select Output
S1 S Y
Combinational circuit that receives binary information from one of 2n input data lines and directs it to a single input line
Also called data selector
De-multiplexer works in opposite manner, accepts single input line and produces 2n output lines

3. Review of Basics of Digital Electronics 3 Lecture 3
Decoder/Encoder
1 d d
E A1 A0 D0 D1 D2 D3
2-to-4 Decoder
Combinational circuit that converts binary information from the n coded inputs to a maximum of 2n unique outputs
A decoder with n inputs and m outputs is referred to as n X m decoder, where m<= 2n
Decoder is enabled when E=1
Encoders works in opposite manner, accepts 2n input lines and produces n outputs A0 A1 E D0 D1 D2 D3

4. De-multiplexer :

5. Octal to Binary Encoder
Review of Basics of Digital Electronics Lecture 3
Decoder/Encoder
D7 D6 D5 D4 D3 D2 D1 D0 A2 A1 A0
Octal to Binary Encoder D1 D2 D3 D5 D6 D7 D4 A0 A1 A2
A0 = D1 + D3 + D5 + D7
A1 = D2 + D3 + D6 + D7
A2 = D4 + D5 + D6 + D7
CSE 211, Computer Organization and Architecture Harjeet Kaur, CSE/IT

6. Decoder Expansion Review of Basics of Digital Electronics 6 Lecture 3
CSE 211, Computer Organization and Architecture Harjeet Kaur, CSE/IT