Computer Hardware & Operation

Northern College DiplomaPhilip Bird

Computer Fundamentals Philip Bird

NOT Gate

NOT

Rule:

The output is the opposite of the input.

In Out

0 1

1 0

0 1

1 0

Computer Fundamentals Philip Bird

0

0

1

1

1

1

AND Gate

AND

Rule:

The output is 1 if all the inputs are 1.

In1 In2 Out

0 0 0

0 1 0

1 0 0

1 1 1

0

0

0

Computer Fundamentals Philip Bird

0

1

1

1

1

1

0

0

0

OR Gate

OR

Rule:

The output is 1 if any of the inputs are 1.

In1 In2 Out

0 0 0

0 1 1

1 0 1

1 1 1

Computer Fundamentals Philip Bird

1

0

1

0

0

0

0

1

1

XOR Gate

XOR

Rule:

The output is 1 if either of the inputs are 1 but not both.

In1 In2 Out

0 0 0

0 1 1

1 0 1

1 1 0

Computer Fundamentals Philip Bird

Logic in Hardware

1906 Lee de Forrest

The Valve

1947 Bardeen and Brattain

Transistor

1958 Jack KilbyIntegrated Circuit

1971 Ted Hoff

Microprocessor

Computer Fundamentals Philip Bird

A Non-Computing Logic Problem

To do teacher training at University I will need to do Maths GCSE (M) and get either the Diploma (D) or the Access to HE Certificate (A)

M D A X U

0 0 0 0 0

0 0 1 1 0

0 1 0 1 0

0 1 1 1 0

1 0 0 0 0

1 0 1 1 1

1 1 0 1 1

1 1 1 1 1

AND

OR

M

D

A

U

X

Computer Fundamentals Philip Bird

Another Example

AND

OR

A

B

C

NOT

AND

A B X Y Z C

0 0

0 1

1 0

1 1

Y

Z

X

0

0

0

1

1

1

1

0

0

1

1

1

0

1

1

0

Computer Fundamentals Philip Bird

Another Example

AND

A

B

CNOT

A B X Y Z C

0 0

0 1

1 0

1 1

Y

ZX

1

1

0

0

1

0

1

0

1

0

0

0

0

1

1

1

NOT

NOT

Computer Fundamentals Philip Bird

Computer Logic Circuits

Made up of logic gates.Distinct units within the CPU doing specific jobs.Simple in operation – clock speed gives computers the power.

Computer Fundamentals Philip Bird

Control Switches & Masks

1

1

0

1

0

0

0

0

0

1

0

1

1

0 1 0 0

0

1

0

0

Computer Fundamentals Philip Bird

Addition Circuits

In1 In2 Carry

Sum

0 0 0 0

0 1 0 1

1 0 0 1

1 1 1 0

Computer Fundamentals Philip Bird

Summary

What are the rules of the logic gates?What is a logic circuit?Why is clock speed so important?Use Circuit Shop to produce the task examples.

Computer Fundamentals Philip Bird

AnswersI will have another beer if I have the money (M) and can stand at the bar (S) or if someone else is buying (B)

B M S X U

0 0 0 0 0

0 0 1 0 0

0 1 0 0 0

0 1 1 1 1

1 0 0 0 1

1 0 1 0 1

1 1 0 0 1

1 1 1 1 1

OR

AND

B

M

S

U

X

Computer Fundamentals Philip Bird

Answers

S R Q

0 0

1 0

0 0

0 1

0 0

0

1

0

0

1