Breadboard Computer Project

WINLAB Summer Internship 2024

Advisors: Dr. Richard Howard, Dr. Richard Martin

Group Members: Dilan Gandhi, Rithvik Madiraju

Project Objective

Overview

The goal of our project is to build an 8-bit computer from scratch on a breadboard using different electrical components like Integrated Circuits, LEDs, Wires, etc.

Specific Goals:

• Construction: Build a fully functional 8-bit computer using discrete components.
• Documentation: Create comprehensive documentation covering each step, allowing others to replicate the process. Our aim is to document the step-by-step process, including schematics, notes, and procedures so that others can replicate the creation of their own Breadboard Computer.

Week 1

Week 1 Presentation

Summary

• Familiarized with breadboard computer components: ICs, logic gates, registers, breadboards, wires, and connectors.
• Learned about fundamental computer components: Fetch-Execute Cycle, CPU, RAM, ALU, and BUS.
• Explored the Fetch-Execute Cycle: Fetch, Decode, Execute.
• Studied the CPU: functions, clock, registers, and ALU.
• Understood RAM: its function, volatility, and direct access capabilities.
• Examined the ALU: performs arithmetic and logical operations.
• Investigated the BUS: facilitates communication between CPU, memory, and peripherals.
• Planned tasks for next week: model and test the ALU using TinkerCad, begin detailed documentation, construct the clock monitor, and build the registers.

Week 2

Week 2 Presentation

Summary

• Started and Finished building different components of the clock module
• Started building the A register
• Added more pictures and videos of testing to the documentation
• Tested and troubleshooted problems related to the Clock Module
  • First LED wasn't blinking
  • Connectivity issues
  • Push button wasn't functioning
    • Fixed issue due to the different pins on the push button

Week 3

Week 3 Presentation

Summary

• Continued and restarted building of the Clock Module
  • Used Oscilloscope to reassure connection
  • Fixed the push button to be powered by 555 chip
  • Technical issue with Blinking LED
  • Fixed response delay from Switch
• Finished building the A-Register
  • Used 2 74LS173 chips and 1 7LS245 chip
• Started building the Random Access Memory (RAM)
  • Used Inverting Chips, Signal Inversion, and Flip-Flop Chips
  
  
  

  Week 4

  Week 4 Presentation

  Summary

  • Continued and restarted building of the Clock Module
  • Completed the construction of the B-Register
    • Used as temporary data storage, one of the operands for the ALU, and holds data during transfers
    • Contains 2 4-bit registers, each storing 4-bits of data
    • Includes bidirectional bus transceivers to facilitate data flow between the B-Register and BUS
  • Continued building the Random Access Memory (RAM)
    • Uses flip-flop chips to store 4 1-bit data units
    • A multiplexer (Quad 2-to-1) is employed to channel multiple data lines into a single line
    • The BUS transceiver chip is an 8-bit tri-state buffer that allows data to flow bidirectionally between two buses
  • Continued documentation, focusing on schematics
  
  
  

  Week 5

  Week 5 Presentation

  Summary

  • Rebuilt the A and B Registers.
  • Completed the construction of the Program Counter.
    • Counts in binary to track which instruction the computer is executing
    • Utilizes JK flip-flops, which are storage elements that count binary numbers
    • Connected to the Clock Module to test counter inputs
  • Nearly finished building the RAM.
  • Successfully completed the Clock Module.
    • Resolved connection issues in all three uses of the 555 Chip: Switch, Button, and Flicker
    • Incorporated three logic gates to connect to the clock signal:
      • NOT Gate: Inverts input signal
      • NAND Gate: Controls clock signal
      • AND Gate: Combines signals
    • Conducted tests with the RAM and Program Counter.
  • Tested RAM through the Clock Module.
  • Continued work on the Instruction Manual.

Week 6