Digital Electronics

Applications: Computers Telecommunication Automation Medical Science and Technology Transportation Space Exploration Entertainment Home Appliances Others

Dr. Bahawodin Baha, University of Brighton, UK.March 2007

Digital Systems, Principles and Applications, 10th EditionR.J Tocci, N. S. Windmer, G. L. Moss, 2007.

Course Summary

Overview of Electronics

Digital Electronics Number systems, decimal, binary, hexadecimal

Combinational logic circuits

Sequential logic circuits

Computer Systems

Combinational Logic Systems Number systems: Binary, decimal and hexadecimal

conversions and calculations Basic logic gates: AND, OR, NOT and Ex-OR

Truth tables, Boolean equations. Combinational logic circuit design: General hierarchical logic

design methodology Minimisation using Karnaugh maps and Boolean algebra,

De-Morgan’s laws. Simulation of gates and combinational logic designs Implementation and testing of designs using a suitable

version of TTL series ICs. Practical aspects of using logic ICs: data sheets, current

and voltage characteristics, timing issues, output types, compatibility, families etc..

Course Summary (cont.)

Course Summary (cont.)

Sequential logic designFlip-flops: SR, JK, D, T types, truth tables,

excitation tables and device operation.

Flip-flop applications: Registers and counters (asynchronous); MSI and LSI devices

Synchronous counter and sequence generator design method

Course Summary (cont.)

Introduction to Microprocessor SystemsOverview of computer systems

architectures, a simple microprocessor-based system, the stored programme concept.

Design of a microprocessor based system

Differences between microprocessors and microcontrollers.

Brief history of microprocessors and microcontrollers.

Overview of Electronics

Analogue electronics

Power electronics

Physical electronics

Differences between digital and other types of electronics

Numerical Presentation

In 1947, Transistor was invented in Bell labs in the USA.

It was as tall as the face of wristwatch.In November 2001, another Bell lab

team has built a transistor from a single Molecule - small enough to fit about 10 million transistors on the head of a pin.

Numerical Representation

There is two ways to represent numerical values. 1- Analogue In analogue representation one quantity is represented by

another quantity which is directly proportional to the first quantity.

Analogue = Continuous 2- Digital In digital representation the quantities are not represented

by proportional quantities but symbols called digits. The digital representation is in discrete steps.

Digital = Discrete Logic Level in digital representation, 0 – 0.8 logic 0 and 2 –

5 logic 1. Voltage between 0.8 V and 2 V are unacceptable and are

never used.

Number systems

Type of NumbersDecimal, Binary, Octal and

Hexadecimal

Converting decimal to binary and

Converting decimal to hexadecimal

Converting binary to hexadecimal

Number Systems

DecimalBase of 10

BinaryBase 0f 2

HexadecimalBase of 16

0 0000 0

1 0001 1

2 0010 2

3 0011 3

4 0100 4

5 0101 5

6 0110 6

7 0111 7

8 1000 8

9 1001 9

10 1010 A

11 1011 B

12 1100 C

13 1101 D

14 1110 E

15 1111 F

Converting Decimal to Binary

Convert Therefore, 810 = (1000)2

LSB, Less Significant Bit

MSB, Most significant Bit

To examine (0 X 2 0) + (0 X 2 1) +

(0 X 2 2) + (1 X 2 3) = 8 decimal into binary

8

4

1

2

0

2

2

2

2

Reminder0

0

0

1

LSB

MSB

2nd Example

Convert 624 decimal into binary

624 decimal = 1001110000 in binary.

To examine the result (1 X 2 4) + (1 X 2 5) +

(1 X 2 6) + (1 X 2 9) = 624

624 Reminder2

156

312

19

39

2

2

2

2

278

9

4

2

1

0

2222

2

0

0

0

0

0

0

1

1

1

1 MSB

LSB

Converting Decimal to Hex

Find the Hex equivalent of (3875)

(3875) = (F23)H To examine (15 X 162) + (2 X

161) + (3 X 160) = 3875

3875 Reminder16

3

2

150MSB

LSB24216

1516

16

Converting Hex to Decimal

Convert (AF16B)16 to decimal.

(AF16B)16 = [(10 X 164) + (15 X 163) + (1 X 162) + (6 X 161) + (11 X 160)]

= (655360 + 61440 +256 +96 +11)

= (717163)10

Converting Binary to Hex

To convert Binary into Hex, simply group them in four and write down the Hex equivalent for each group.

Example:(10110011) 2 = (1011)2 (0011)2 =

(11)10 (3)10 = B316

Main Points

Digital Electronics use many exciting applications

Introduction to digital electronics Number systems: Decimal, binary

and hex Converting from one number system

into another

The End

Thank you for your attention.

Any questions? Good luck and

have fun!