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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.

Breadboard Computer Instruction Manual

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.