4-Bit Arithmetic Logic Unit (ALU) - DLD Lab Project

A theoretical design and simulation of a basic 4-bit Arithmetic Logic Unit (ALU), created as a project for a Digital Logic Design course. This project focuses on the hardware implementation of addition and subtraction operations using fundamental logic chips.

🧠 Project Overview

This ALU is a combinational circuit that performs two core arithmetic operations on two 4-bit binary inputs (A and B), selected by a mode bit (M0). The result is displayed on a 7-segment display.

Mode (M0)	Operation	Output
0	Addition	F = A + B
1	Subtraction	F = A - B

⚙️ Implementation

The design was implemented and simulated in Tinkercad using the following integrated circuits (ICs):

• 1x 74LS83: 4-bit binary full adder (Core of the arithmetic unit)
• 1x 74153: Dual 4-line to 1-line data selector/multiplexer (Used for mode selection)
• 1x 7447: BCD-to-seven segment decoder (Drives the display)
• 1x Common-Anode Seven-Segment Display
• DIP Switches & Toggle Switches for inputting values and selecting the mode.

📊 Key Features

• 4-bit Data Processing: Handles binary numbers from 0000 to 1001 (0 to 9 in decimal).
• Two Operations: Performs both addition and subtraction based on the control input.
• Visual Output: Displays the result on a 7-segment LED display.
• Combinational Logic: Output is purely dependent on the current inputs (no clock/sequential logic).

📁 Project Contents

This repository contains the design documentation and report for the project, which includes:

• Circuit design and logic equations.
• Screenshots of the complete functional simulation from Tinkercad.

Tinkercard links:

• circuit using the common cathode-seven segment display: https://www.tinkercad.com/things/4zg2yJoilSE-final-project-cathode-display-

• circuit using the common anode-seven segment display: https://www.tinkercad.com/things/1a99QJrJVm1-final-project-anode-display-

This project was a theoretical exercise in digital circuit design and simulation.