Logic Lab

CS63: Principles of Computer Organization
Fall Semester, 1997

Ray Ontko
Department of Computer Science
Earlham College

The purpose of this lab is to give you a chance to explore complex logic gate circuits as a way of understanding gate, transformation of AND/OR/NOT circuits to NAND/NOR/NOT circuits, and to develop a clearer notion of how elementary circuits can be combined to perform useful tasks.

1) Using a digital logic simulation program such as DigSim by Brian Rauchfuss, LogicSim by Arnaud Masson, or DigitalSimulator by Andreas Herz, create one or more of the following:

1-bit ALU
4-bit adder
4-bit adder with fast carry
8-bit left/right shifter
8-bit left/right shifter with rotate option
4-input multiplexor
8-input multiplexor
2-to-4 decoder
3-to-8 decoder
4-bit comparator
4-bit comparator with GT and LT outputs
8-bit comparator
8-bit negation (i.e., negation is under control of an input line)

2) Implement one of the following circuits using NOT/NAND/NOR gates only:

3-input OR
3-input AND
1-bit half-adder
1-bit full-adder

Demonstrate each to the person next to you.