ECE 547 - UNIVERSITY OF MAINE 1
8-Bit Arithmetic Logic Unit
Samuel Winchenbach, Department of Electrical and Computer Engineering
Mohammed Driss, Department of Electrical and Computer Engineering
University of Maine, Orono
CONTENTS
I Introduction 2
I-A Project Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
I-B Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
II Circuit Design 2
II-A Logic Gates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
II-B 4 Bit ALU Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
II-C Multiplexer/Path Selector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
II-D 8 Bit ALU Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
III Design Verification 4
IV Physical Design 4
V Circuit Performance 5
VI Test And Characterization 5
VII 4 Bit ALU Verilog Verification Code 9
VIII 8 Bit ALU Verilog Verification Code 11
IX Circuit Schematics 13
References 15
Biographies 15
Samuel A Winchenbach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Mohammed Driss . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Abstract
Digital design is an amazing and very broad field. The applications of digital design are present in our daily life, including
Computers, calculators, video cameras etc. In fact, there will be always need for high speed and low power digital products which
makes digital design a future growing business. ALU (Arithmetic logic unit) is a critical component of a microprocessor and is
the core component of central processing unit. Furthermore, it is the heart of the instruction execution portion of every computer.
ALU’s comprise the combinational logic that implements logic operations, such as AND and OR, and arithmetic operations, such
as ADD and SUBTRACT. We designed and had fabricated an 8-bit ALU (Arithmetic logic unit) that is formed by combining
three 74S181 [1], 4-bit ALUs, and five multiplexers.