Instruction decoder

Modular 8-bit "Simple as Possible" TTL-Logics Computer

This project showcases the design and construction of a modular 8-bit computer built with TTL logic units. The core principle behind the project is to create a "Simple as Possible" system, focusing on simplicity, modularity, and compactness.

Key Features

• TTL Logic-Based Design: The computer is built using traditional TTL (Transistor-Transistor Logic) components, adhering to a fundamental, hands-on approach to computing.
• Modular Architecture: Designed for modularity, each functional unit (ALU, registers, memory, control logic, etc.) is implemented as a separate module, allowing for easy debugging, customization, and scalability.
• Compact Form Factor: By predominantly using SMD (Surface-Mount Device) components, the overall size of the computer is significantly reduced compared to traditional through-hole designs, making it more efficient and portable.
• Educational Value: Serves as an excellent learning resource for understanding the basic principles of digital logic, computer architecture, and how these concepts come together to form a functional computing system.
• Customization Potential: The modular approach allows users to experiment with different configurations and expand the system to suit specific needs or projects.

Technical specifications

• 8 bit program counter
• 256 bytes of RAM and 256 bytes of program ROM
• 256 configurable programs via a dip switch
• Three general-purpose register: A, B and T
• Simple ALU allowing for addition and subtraction
• EEPROM-configurable instruction decoder
• Custom assembly language including Python-based assembler

Goals of the Project

The project aims to:

1. Simplify Complexity: Break down the workings of a computer into comprehensible modules without unnecessary abstraction.
2. Promote Learning: Provide an accessible platform for enthusiasts, educators, and students to explore computer design.
3. Encourage Miniaturization: Demonstrate how SMD components can be used effectively in hobbyist and educational projects to save space while maintaining functionality.

Why SMD Components?

SMD components offer several advantages:

• Space Efficiency: Significantly smaller than through-hole components, enabling more compact designs.
• Modern Availability: Easier to source and more reflective of contemporary electronics practices.
• Scalability: Allows for a more complex system without requiring excessive physical space.

Who Is This For?

This project is ideal for:

• Hobbyists and Makers interested in retrocomputing and hardware design.
• Students and Educators looking for hands-on experience with digital logic and computing fundamentals.
• Researchers and Enthusiasts exploring minimalist computing and modular design approaches.

Getting Started

1. Clone the Repository: Download the files and schematics from this repository.
2. Review the Documentation: Detailed explanations and schematics for each module are available in the docs directory.
3. Assemble and Test: Follow the provided instructions to assemble and test the modules step-by-step.
4. Customize: Modify or expand the design to suit your needs or explore specific areas of interest.

Contributing

Contributions to this project are welcome! If you have ideas for improvements, additional features, or alternative designs, feel free to fork the repository and submit a pull request.