4-Bit Full Adder Using ATmega16

This project implements a 4-bit Full Adder using the ATmega16 microcontroller. It computes the sum and carry-out for two 4-bit binary inputs along with a carry-in signal. The results are displayed using LEDs connected to the microcontroller.

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✨ Features

• 4-bit Binary Addition:
  • Adds two 4-bit numbers (A and B) with a carry-in (Cin).
  • Outputs the Sum and Carry-out (Cout) on LEDs.
• Dynamic Input Handling:
  • Reads inputs directly from PORTA, PORTB, and PINB.
• Assembly Language Implementation:
  • Efficient and optimized for microcontroller use.

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📋 Table of Contents

1. Overview
2. Requirements
3. Setup Instructions
4. How It Works
5. Project Diagrams
6. References
7. License

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🛠️ Requirements

Hardware:

• ATmega16 Microcontroller //1MHz internal clock used here
• LEDs (5) with 330 Ω resistors
• Push buttons (for binary inputs)
• Breadboard and jumper wires
• 5V Power Supply

Software:

• AVR Studio (for compiling the code)
• Proteus (for circuit simulation)

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🚀 Setup Instructions

1. Assemble the Circuit:

   • Connect inputs (A, B, and Cin) to PORTA, PORTB, and PINB, respectively.
   • Connect outputs (Sum and Carry) to PORTC, where LEDs are attached.
   • Use pull-down resistors with input buttons for stable signals.

2. Load the Assembly Code:

   • Open 4bit_full_adder.asm in AVR Studio.
   • Compile the file to generate the .hex file.

3. Program the Microcontroller:

   • Use a suitable programmer (e.g., USBasp) to flash the .hex file to the ATmega16.

4. Run the Simulation:

   • Simulate the circuit using Proteus to validate functionality.
   • Test the hardware circuit with various input combinations.

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⚙️ How It Works

1. Initialization:

   • Input ports (PORTA and PORTB) are configured as inputs.
   • Output port (PORTC) is configured to drive LEDs.

2. Input Handling:

   • Binary values for A and B are read from PORTA and PORTB.
   • Cin is derived from the 5th bit of PINB (via SBRC and SBRS instructions).

3. Calculation:

   • A, B, and Cin are added using the ADD instruction.
   • Carry-out is detected using bitwise operations.

4. Output Display:

   • Sum and Carry-out values are written to PORTC, lighting up the corresponding LEDs.

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📊 Project Diagrams

Circuit Diagram

• Example: A = 6 , B = 4, Cin = 1 (in decimal) || Sum = 11, Cout = 0 (in decimal)

Flowchart

Pinout Diagram

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🔗 References

• ATmega16 Datasheet
• AVR Assembly Language Tutorial
• Proteus Circuit Simulation Tool //version 8.10 used in this project.