Experiment #2: Introduction to Logic Functions and their

Gate-Level Hardware Implementations

CPE 169

Digital Design

Laboratory

Basic Logic Functions

• Defined with Truth Tables

AND OR Complement

A B F

0 0 0

0 1 0

1 0 0

1 1 1

A B F

0 0 0

0 1 1

1 0 1

1 1 1

A F

0 1

1 0

Basic Logic Gates

• Hardware used to implement logic functions

AND OR Complement

Other Common Logic Gates• Can be constructed from basic logic gates

NAND NOR XOR

A B F

0 0 1

0 1 1

1 0 1

1 1 0

A B F

0 0 1

0 1 0

1 0 0

1 1 0

A B F

0 0 0

0 1 1

1 0 1

1 1 0

Nexys Development Board

Nexys Board

Integrated Circuits (ICs)• ICs contain logic gates• SSI (small scale integration) 50-100

transistors per IC• DIPs (dual in-line packages) • Require power supply (Vcc, GND)

7400 Package Interior Layout 7400 Dual In-Line Package

Circuit Implementation on Nexys Board

• Chips (IC’s) are place on Solderless Breadboard• Solid-core wire connect circuit elements• Power (Vcc) and Ground (GND) from Nexys

Solderless Breadboard• Physical connections made without soldering• Certain holes are physically connected to other holes

physical hole connections

Circuit Connections to Nexys Signals

• Solid-core wire used for circuit connections to the Expansion Connector

Nexys BoardNexys Expansion

Connectors

Detailed Schematic Diagram

• Normal schematic diagram plus various IC related information:

• Pin numbers• IC labels• Gate labels

Schematic Diagram Detailed Schematic Diagram

Experiment 2 Procedure Overview

• Implement basic logic circuits on the breadboard using Integrated Circuits

2-Input NAND4-Input NAND 2-Input XOR2-Input AND

Made from NAND + Inverter (also from NAND)

• Verify your hardware implementations of each logic function.

HEY!!There’s no

#&$@^! “AND” gate IC in my Parts Kit !!?!

??