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Benm 1143 Logic Circuits

This document discusses various combinational logic circuits including adders, comparators, decoders, encoders, multiplexers, and parity generators/checkers. It provides details on half adders, full adders, parallel binary adders, 1-bit and 2-bit comparators, binary decoders, BCD to decimal decoders, decimal to BCD encoders, 8-line to 3-line encoders, 4-input multiplexers, 2-line to 4-line demultiplexers, and parity generators/checkers. Diagrams and truth tables are provided to illustrate the logic and function of these basic digital circuits.

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240 views21 pages

Benm 1143 Logic Circuits

This document discusses various combinational logic circuits including adders, comparators, decoders, encoders, multiplexers, and parity generators/checkers. It provides details on half adders, full adders, parallel binary adders, 1-bit and 2-bit comparators, binary decoders, BCD to decimal decoders, decimal to BCD encoders, 8-line to 3-line encoders, 4-input multiplexers, 2-line to 4-line demultiplexers, and parity generators/checkers. Diagrams and truth tables are provided to illustrate the logic and function of these basic digital circuits.

Uploaded by

badhell_18
Copyright
© Attribution Non-Commercial (BY-NC)
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PPT, PDF, TXT or read online on Scribd
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BENM 1143 LOGIC CIRCUITS

CHAPTER 4
Functions of Combinational Logic

Slide 1
4.1 BASIC ADDER
4.1.1 Half-Adder

Simple Binary Addition


0+0=0 Zero plus zero equals zero
0+1=1 Zero plus one equals one
1+0=1 One plus zero equals one
1 + 1 = 10 One plus one equals zero with a carry
of one

Slide 2
4.1.1 Half-Adder (cont…)

Slide 3
4.1.2 Full-Adder

Slide 4
4.1.2 Full-Adder (cont…)

• Full adder from two half-adder circuits

Slide 5
4.1.3 Parallel Binary Adders

• Two-bit parallel binary adder

Slide 6
4.1.3 Parallel Binary Adders (cont…)

• Four-bit parallel binary adder

Slide 7
4.2 COMPARATORS

4.2.1 1-Bit Comparator

The output is 1 when the inputs are equal

Slide 8
4.2 COMPARATORS (cont…)

4.2.2 2-Bit Comparator

The output is 1 when A0 = B0 AND A1 = B1

Slide 9
4.2 COMPARATORS (cont…)
4.2.3 4-Bit Comparator
One of three outputs will be HIGH:
• A greater than B (A > B)
• A equal to B (A = B)
• A less than B (A < B)

Slide 10
4.3 DECODER
• Binary decoder
The output is 1 only when:
A0 = 1
A2 = 0
A3 = 0
A4 = 1

This is only one of an infinite number of examples

Slide 11
4.3 DECODER (cont…)
• 4-bit decoder

Logic
Diagram

Slide 12
4.3 DECODER (cont…)
• 4-bit decoder

– Binary inputs

– Active-low
outputs

Truth
Table

Slide 13
4.3 DECODER (cont…)
• BCD-to-decimal decoder

Slide 14
4.3 DECODER (cont…)
• BCD-to-7-segement decoder

Logic
Diagram

Slide 15
4.3 DECODER (cont…)
• BCD-to-7-segement decoder

Truth
Table

Slide 16
4.4 ENCODER
• Decimal-to-BCD encoder

Slide 17
4.4 ENCODER (cont…)
• 8-line-to-3-line encoder

Slide 18
4.5 MULTIPLEXER (Data Selectors)
• 4-input multiplexer

Slide 19
4.5 DEMULTIPLEXER
• 2-line-to4-line demux

Slide 20
4.5 PARITY GENERATOR/CHECKER
• Parity generator/checker

Slide 21

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