🎨 22-Bit CPU Design Using Logisim

🛠️ Overview

This project demonstrates the design and implementation of a 22-bit CPU using Logisim, a graphical logic circuit simulator. The CPU features modular components, including an Arithmetic Logic Unit (ALU), a Control Unit, and memory modules (ROM and RAM). It supports:

• ✅ Arithmetic calculations
• ✅ Bitwise logic operations
• ✅ Memory management

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🚀 Key Features

🔢 1. Arithmetic Logic Unit (ALU)

• Performs:
  • ➕ Addition
  • ➖ Subtraction
  • 🔗 Bitwise Operations: AND, OR, NAND, NOR.
• Includes universal gates for logical computations.

🎛️ 2. Control Unit

• Decodes and executes instructions from ROM.
• Controls data flow between CPU components.

📝 3. Instruction Set

• Custom opcodes for various operations:
  • Bitwise AND: 0
  • Addition: 1
  • Subtraction: 4
  • NAND: 7
  • Halt: 9

🗂️ 4. Memory Management

• RAM: Temporarily stores data during execution.
• ROM: Preloaded with instruction codes.

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💻 Instruction Format

• Opcode (4 bits): Specifies the operation.
• Data Bits (Remaining bits): Encodes operand and address.

Instruction Examples

🔧 Operation	📜 Machine Code
Load	18000f
Add	04000c
Store	08000a
Halt	240000

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⚙️ How It Works

1. Instruction Execution:
   • Fetch instructions from ROM.
   • Decode opcode and execute with the ALU or memory.
2. Data Flow:
   • Seamless data flow between components.
3. Simulation:
   • Built and tested using Logisim with real-time clock control.

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🛠️ Technologies Used

• Logisim: Circuit design and simulation.
• Multiplexers: Operation selection.
• Logic Gates: Logical and arithmetic operations.
• ROM/RAM: Instruction and data storage.

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