# CS201 Lab: Combinational Design

## Objective of this lab:

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To verify combinational design procedures by testing designed circuits.

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## Preparation

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Read lab lecture notes which contains the Combinational Design Procedure.

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## Lab Assignments

1. Design and implement a 4-input majority detector.
• The output is high if two or more of the inputs are high.
• Use Karnaugh map reduction to get the simplified Boolean function.
• Draw the circuit and simulate the circuit in LogicWorks.
• Check if the truth table for the circuit meets the result of your experiment.
• For your lab assignment, make sure that you follow the combinational design procedures.
Marks will be given to each step.
Hand-In
• The six steps used to solve this problem.
Note: Step 5 (drawing the logic diagram) and Step 6 (implementing the test circuit) can both be done in LogicWorks.

2. Design a circuit which will control LED segment "c" of a 7-Segment display.
• See the diagram below to understand what a "c" segment is.
• If the segment is lit, then the output should be 1. If the segment is not lit, then the output should be 0.
• For example, for the numbers 0, 3, and 4, segment "c" should be lit;
for numbers 1, and 2, segment "c" should not be lit; etc.
• Design the circuit so that if someone applies a value from 10 to 15 then the LED segment does not light.

The following guidelines apply to the 2nd part of the lab assignment:

• You may only use NAND and NOT gates (it is common to have your design limited to certain gates).
• Show all the steps of the combinational design procedure including test results.
• Present the simplified SOP form after using the Karnaugh map reduction method.
• Present the expression that can be implemented by using NAND and NOTgates.
• Print out the circuit when inputs are 1, 3, 9 and 11.
• A 7-segment display can display the digits 0 - 9 by having the appropriate LEDs turned on.

Hand-In
• The six steps used to solve this problem
(Remember the two expressions are needed.)
• Print out of the circuit when input is 1, 3, 9, and 11

Copyright: Department of Computer Science, University of Regina.