View by Category

Loading...

PPT – Combinational Logic PowerPoint presentation | free to view

The Adobe Flash plugin is needed to view this content

About This Presentation

Write a Comment

User Comments (0)

Transcript and Presenter's Notes

Chapter 4

Combinational Circuits

- Output is function of input only
- i.e. no feedback
- When input changes, output may change (after a

delay)

Combinational Circuits

n inputs

m outputs

?

Combinational Circuits

- Analysis
- Given a circuit, find out its function
- Function may be expressed as
- Boolean function
- Truth table
- Design
- Given a desired function, determine its circuit
- Function may be expressed as
- Boolean function
- Truth table

Analysis Procedure

- Boolean Expression Approach

ABC

ABC

AB'C'A'BC'A'B'C

(AB)(AC)(BC)

ABACBC

F1AB'C'A'BC'A'B'CABC F2ABACBC

Analysis Procedure

- Truth Table Approach

0 0

0 0 0 0 0 0 0 0 0 0

0 0

0 0 0 0 0

0

0

1

0

Analysis Procedure

- Truth Table Approach

0 0 1 0 0 1 0 0 0 1

0 1

0 1 0 0 0

1

1 0

1

1

0

Analysis Procedure

- Truth Table Approach

0 1 0 0 1 0 0 1 0 0

1 0

0 1 0 0 0

1

1 0

1

1

0

Analysis Procedure

- Truth Table Approach

0 1 1 0 1 1 0 1 0 1

1 1

0 1 0 0 1

0

0

0 1

0

1

Analysis Procedure

- Truth Table Approach

1 0 0 1 0 0 1 0 1 0

0 0

0 1 0 0 0

1

1

1 0

1

0

Analysis Procedure

- Truth Table Approach

1 0 1 1 0 1 1 0 1 1

0 1

0 1 0 1 0

0

0

0

0 1

1

Analysis Procedure

- Truth Table Approach

1 1 0 1 1 0 1 1 1 0

1 0

0 1 1 0 0

0

0

0

0 1

1

Analysis Procedure

- Truth Table Approach

1 1 1 1 1 1 1 1 1 1

1 1

1 1 1 1 1

1

0

0

1

1 1

F1AB'C'A'BC'A'B'CABC

F2ABACBC

Design Procedure

- Given a problem statement
- Determine the number of inputs and outputs
- Derive the truth table
- Simplify the Boolean expression for each output
- Produce the required circuit
- Example
- Design a circuit to convert a BCD code to

Excess 3 code

- 4-bits
- 0-9 values

- 4-bits
- Value3

Design Procedure

- BCD-to-Excess 3 Converter

w ABCBD

x BCBDBCD

y CDCD

z D

Design Procedure

- BCD-to-Excess 3 Converter

w A B(CD)

y (CD) CD

x B(CD) B(CD)

z D

Seven-Segment Decoder

BCD code

a w y xz xz

b . . .

c . . .

d . . .

Binary Adder

- Half Adder
- Adds 1-bit plus 1-bit
- Produces Sum and Carry

x y --- C S

Binary Adder

- Full Adder
- Adds 1-bit plus 1-bit plus 1-bit
- Produces Sum and Carry

x y z --- C S

S xy'z'x'yz'x'y'zxyz x ? y ? z

C xy xz yz

Binary Adder

- Full Adder

S xy'z'x'yz'x'y'zxyz x ? y ? z

C xy xz yz

x y z

S C

S C

x y z

Binary Adder

- Full Adder

HA

HA

x y z

S C

x y z

S C

Binary Adder

c3 c2 c1 . x3 x2 x1 x0 y3 y2 y1

y0

-------- Cy S3 S2 S1 S0

Carry Propagate Addition

x3 x2 x1

x0

y3 y2 y1

y0

0

FA

FA

FA

FA

C4 C3 C2

C1

S3 S2 S1

S0

Binary Adder

- Carry Propagate Adder

x3 x2 x1 x0

x7 x6 x5 x4

y3 y2 y1 y0

y7 y6 y5 y4

CPA

A3 A2 A1 A0

B3 B2 B1 B0

0

C0

Cy

S3 S2 S1 S0

S3 S2 S1 S0

S7 S6 S5 S4

BCD Adder

- 4-bits plus 4-bits
- Operands and Result 0 to 9

x3 x2 x1 x0 y3 y2 y1 y0 -------- Cy

S3 S2 S1 S0

Invalid Code

Wrong BCD Value

0001 1000

BCD Adder

? ? ? ? ? ? ? ? ?

6

BCD Adder

- Correct Binary Adders Output (6)
- If the result is between A and F
- If Cy 1

Err S3 S2 S3 S1

BCD Adder

Err

Binary Subtractor

- Use 2s complement with binary adder
- x y x (-y) x y 1

Binary Adder/Subtractor

- M Control Signal (Mode)
- M0 ? F x y
- M1 ? F x y

Overflow

- Unsigned Binary Numbers
- 2s Complement Numbers

Carry

Overflow

Magnitude Comparator

- Compare 4-bit number to 4-bit number
- 3 Outputs
- Expandable to more number of bits

A3A2A1A0 B3B2B1B0

Magnitude Comparator

AB

Magnitude Comparator

Magnitude Comparator

x3 x2 x1 x0

x7 x6 x5 x4

y3 y2 y1 y0

y7 y6 y5 y4

MagnitudeComparator

A3 A2 A1 A0

B3 B2 B1 B0

0 1 0

I(AB) I(AB) I(AAB

AB

Decoders

- Extract Information from the code
- Binary Decoder
- Example 2-bit Binary Number

Only one lamp will turn on

1 0 0 0

0 0

Decoders

- 2-to-4 Line Decoder

Decoders

- 3-to-8 Line Decoder

Decoders

- Enable Control

Decoders

- Expansion

I2 I1 I0

Decoders

- Active-High / Active-Low

Implementation Using Decoders

- Each output is a minterm
- All minterms are produced
- Sum the required minterms
- Example Full Adder
- S(x, y, z) ?(1, 2, 4, 7)
- C(x, y, z) ?(3, 5, 6, 7)

Implementation Using Decoders

Encoders

- Put Information into code
- Binary Encoder
- Example 4-to-2 Binary Encoder

Only one switch should be activated at a time

Encoders

- Octal-to-Binary Encoder (8-to-3)

Priority Encoders

- 4-Input Priority Encoder

Encoder / Decoder Pairs

BinaryEncoder

BinaryDecoder

Y7 Y6 Y5 Y4 Y3 Y2 Y1 Y0

I7 I6 I5 I4 I3 I2 I1 I0

Y2 Y1 Y0

I2 I1 I0

Multiplexers

Multiplexers

- 2-to-1 MUX
- 4-to-1 MUX

Multiplexers

- Quad 2-to-1 MUX

x3 x2 x1 x0

y3 y2 y1 y0

S

Multiplexers

- Quad 2-to-1 MUX

Extra Buffers

Implementation Using Multiplexers

- ExampleF(x, y) ?(0, 1, 3)

1 1 0 1

F

x y

Implementation Using Multiplexers

- ExampleF(x, y, z) ?(1, 2, 6, 7)

0 1 1 0 0 0 1 1

F

x y z

Implementation Using Multiplexers

- ExampleF(x, y, z) ?(1, 2, 6, 7)

z

F z

F

z

0

F z

1

F 0

x y

F 1

Implementation Using Multiplexers

- ExampleF(A, B, C, D) ?(1, 3, 4, 11, 12, 13,

14, 15)

D

F D

D

F D

D

0

F D

F

0

F 0

D

F 0

1

F D

1

F 1

F 1

A B C

Multiplexer Expansion

- 8-to-1 MUX using Dual 4-to-1 MUX

0 0

1

DeMultiplexers

Multiplexer / DeMultiplexer Pairs

MUX

DeMUX

Y7 Y6 Y5 Y4 Y3 Y2 Y1 Y0

I7 I6 I5 I4 I3 I2 I1 I0

Y

I

S2 S1 S0

S2 S1 S0

Synchronize

x2 x1 x0

y2 y1 y0

DeMultiplexers / Decoders

Three-State Gates

- Tri-State Buffer
- Tri-State Inverter

A

Y

C

Three-State Gates

A

Y

C

B

Not Allowed

D

A if C 1 B if C 0

Y

Three-State Gates

I3

I2

Y

I1

I0

BinaryDecoder

Y3 Y2 Y1 Y0

I1 I0 E

S1

S0

E

Homework

- Mano
- Chapter 4
- 4-2
- 4-3
- 4-5
- 4-11
- 4-13
- 4-27
- 4-28
- 4-31
- 4-32
- 4-33
- 4-35

Homework

- Mano

Homework

Homework

Homework

Homework

Homework

About PowerShow.com

PowerShow.com is a leading presentation/slideshow sharing website. Whether your application is business, how-to, education, medicine, school, church, sales, marketing, online training or just for fun, PowerShow.com is a great resource. And, best of all, most of its cool features are free and easy to use.

You can use PowerShow.com to find and download example online PowerPoint ppt presentations on just about any topic you can imagine so you can learn how to improve your own slides and presentations for free. Or use it to find and download high-quality how-to PowerPoint ppt presentations with illustrated or animated slides that will teach you how to do something new, also for free. Or use it to upload your own PowerPoint slides so you can share them with your teachers, class, students, bosses, employees, customers, potential investors or the world. Or use it to create really cool photo slideshows - with 2D and 3D transitions, animation, and your choice of music - that you can share with your Facebook friends or Google+ circles. That's all free as well!

For a small fee you can get the industry's best online privacy or publicly promote your presentations and slide shows with top rankings. But aside from that it's free. We'll even convert your presentations and slide shows into the universal Flash format with all their original multimedia glory, including animation, 2D and 3D transition effects, embedded music or other audio, or even video embedded in slides. All for free. Most of the presentations and slideshows on PowerShow.com are free to view, many are even free to download. (You can choose whether to allow people to download your original PowerPoint presentations and photo slideshows for a fee or free or not at all.) Check out PowerShow.com today - for FREE. There is truly something for everyone!

You can use PowerShow.com to find and download example online PowerPoint ppt presentations on just about any topic you can imagine so you can learn how to improve your own slides and presentations for free. Or use it to find and download high-quality how-to PowerPoint ppt presentations with illustrated or animated slides that will teach you how to do something new, also for free. Or use it to upload your own PowerPoint slides so you can share them with your teachers, class, students, bosses, employees, customers, potential investors or the world. Or use it to create really cool photo slideshows - with 2D and 3D transitions, animation, and your choice of music - that you can share with your Facebook friends or Google+ circles. That's all free as well!

For a small fee you can get the industry's best online privacy or publicly promote your presentations and slide shows with top rankings. But aside from that it's free. We'll even convert your presentations and slide shows into the universal Flash format with all their original multimedia glory, including animation, 2D and 3D transition effects, embedded music or other audio, or even video embedded in slides. All for free. Most of the presentations and slideshows on PowerShow.com are free to view, many are even free to download. (You can choose whether to allow people to download your original PowerPoint presentations and photo slideshows for a fee or free or not at all.) Check out PowerShow.com today - for FREE. There is truly something for everyone!

presentations for free. Or use it to find and download high-quality how-to PowerPoint ppt presentations with illustrated or animated slides that will teach you how to do something new, also for free. Or use it to upload your own PowerPoint slides so you can share them with your teachers, class, students, bosses, employees, customers, potential investors or the world. Or use it to create really cool photo slideshows - with 2D and 3D transitions, animation, and your choice of music - that you can share with your Facebook friends or Google+ circles. That's all free as well!

For a small fee you can get the industry's best online privacy or publicly promote your presentations and slide shows with top rankings. But aside from that it's free. We'll even convert your presentations and slide shows into the universal Flash format with all their original multimedia glory, including animation, 2D and 3D transition effects, embedded music or other audio, or even video embedded in slides. All for free. Most of the presentations and slideshows on PowerShow.com are free to view, many are even free to download. (You can choose whether to allow people to download your original PowerPoint presentations and photo slideshows for a fee or free or not at all.) Check out PowerShow.com today - for FREE. There is truly something for everyone!

For a small fee you can get the industry's best online privacy or publicly promote your presentations and slide shows with top rankings. But aside from that it's free. We'll even convert your presentations and slide shows into the universal Flash format with all their original multimedia glory, including animation, 2D and 3D transition effects, embedded music or other audio, or even video embedded in slides. All for free. Most of the presentations and slideshows on PowerShow.com are free to view, many are even free to download. (You can choose whether to allow people to download your original PowerPoint presentations and photo slideshows for a fee or free or not at all.) Check out PowerShow.com today - for FREE. There is truly something for everyone!

Recommended

«

/ »

Page of

«

/ »

Promoted Presentations

Related Presentations

Page of

Page of

CrystalGraphics Sales Tel: (800) 394-0700 x 1 or Send an email

Home About Us Terms and Conditions Privacy Policy Contact Us Send Us Feedback

Copyright 2015 CrystalGraphics, Inc. — All rights Reserved. PowerShow.com is a trademark of CrystalGraphics, Inc.

Copyright 2015 CrystalGraphics, Inc. — All rights Reserved. PowerShow.com is a trademark of CrystalGraphics, Inc.

The PowerPoint PPT presentation: "Combinational Logic" is the property of its rightful owner.

Do you have PowerPoint slides to share? If so, share your PPT presentation slides online with PowerShow.com. It's FREE!

Committed to assisting Psut University and other schools with their online training by sharing educational presentations for free