Tags: #◇Computer Science #◇CSARCH1 #◇Computer Architecture #◇Combinational Circuits #◇Combinational Circuit - Design

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Combinational Circuit - Design

◇Overview

This sub-module discusses the design procedure for combinational circuits.
Objective: Learn how to design a combinational circuit.

◇Design Procedure

1. From circuit specifications, determine the required number of inputs and outputs and assign a symbol to each.
2. Derive the truth table that defines the relationship between inputs and outputs.
3. Obtain simplified Boolean functions for each output as a function of input variables (using tools like Karnaugh Maps).
4. Draw the logic diagram and verify the correctness of the design (manually or by simulation).

◇Real World Examples

Code Converter: BCD to Excess-3 code

A code converter is a circuit that makes two systems compatible even though each uses a different binary code.

• Inputs: $A, B, C, D$ with $A$ as MSB.
• Outputs: $w, x, y, z$ with $w$ as MSB.
  Excess-3 code is derived by adding 3 (0011 in binary) to the BCD code.

Majority Voting System

Classes will be suspended based on the vote of the Dean (D), Chairperson (C), Teacher (T), and Student (S).

• Dean's vote = 4 points
• Chairperson's vote = 3 points
• Teacher's vote = 2 points
• Student's vote = 1 point
  Classes will be suspended ($F=1$) if there is a majority vote (sum of points $> 5$).

Truth Table Highlights:

• $F = \sum m(7, 10, 11, 12, 13, 14, 15)$
• Simplified Boolean Equation: $F = DC + DT + CTS$

◇References & Navigation

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