ENGR 338 Lab 2021 Fall
Lab 9
Name: Brian Tsosie
Email: bjtsosie@fortlewis.edu

Simple 8-Bit ALU

Introduction

Building an 8-bit ALU.

Materials and Methods

Pencil & Paper

LT Spice software

Electric VLSI software

Results


Task 1: Logic circuit of the ALU.


Figure 1. Layout of an 8-bit inverter with DRC and NCC.


Figure 2.  Schematic of the 8-bit ALU.


Figure 3. Simulation to verify AND gate by setting S1S0=00.


Figure 4.  Simulation to verify OR gate by setting S1S0=01.


Figure 5.  Simulation verifying AND operation using 1111 1111 + 0000 0001 = S = 0000 0000, Co=1.


Figure 6.  Simulation to verify the subtraction operation.

Task 2: ALU layout.


Figure 7.  8-bit ALU layout.



Discussion

Building the ALU layout proved to be very challenging. While the layout could be considered straight forward, connecting all the components together was not an easy task.
So much that the DRC and a NCC checks did not pass. It was easy to get lost and lose track of what went where and spacing each component just right. Unfortunately, that
is what happen here.