Classes/Building an 8-Bit CPU from Scratch

8-Bit CPU Using Logic Gates

Creator	Andrew Vaughan
Date	May 27, 2017
Estimated Time	16 Weeks
Estimated Cost	$40

In this class, taught by Andrew Vaughan, you will learn how to build a functional (albeit, simple) 8-Bit CPU from scratch using breadboards and TTL Integrated Circuits. No prior electronics experience is required in the class, as the basics are covered in the first lesson. At the end of the course, you will have built a fully-functional, modular CPU, as well as your own personalized Assembly language, that you can extend indefinitely to create more extensive functionality.

Office hours are held before and after each class. The office hours prior to the class (timing of which will be announced with each class) are intended for members who have missed classes and need to catch up on modules for the upcoming lesson. Office hours after each class will provide a list of advanced topics from the lesson plan, which will only be covered if interest is shown. This time is also available to assist with debugging problems in circuits.

Time and Location

Instructor:	Andrew Vaughan (Contact information available on user page)
Where:	Pumping Station: One Electronics Lab (2nd Floor)
When:	TBD
Office Hours:	TBD
Minimum Class Size:	2
Maximum Class Size:	8

Prerequisites

There are minimal prerequisites to attend this class. No prior experience in electronics is needed, nor any experience with soldering or computers. It is important that novices to these are attend the first classes and to make use of office hours to ask questions before continuing into more advanced topics.

Materials

Components and tools will be made available for persons who wish to learn, but do not wish to keep their project after class completion. If parts are borrowed from the electronics space, it is asked that a donation be made, at your discretion, to the Electronics Lab area host. Note that you will be required to return all components used for the class after the course is completed. Persons borrowing equipment will be required to pair with others doing the same, if enough persons are available.

If you, however, wish to keep your project, or want to extend it further after the course is complete (both highly recommended), the following will need to be purchased:

Notice
This section is still under development. Please check back later for more information.

Components

The following components are required to build the CPU project. No components are "consumed" by this project, as long as it is built on a breadboard; so, if you so choose, you may reuse these components in future projects. A bulk-purchase option is given to students at the beginning of each class, which serves to reduce costs. The average cost, per-student, when bulk-purchasing all-new components is generally about $TBD.

Quantity	Component
1	22AWG Solid Wire Kit, Various Colors (see below)
14	Full-Sized (830-Point) Breadboards†

^† For advanced participants familiar with soldering, StripBoard can be used instead to save space and money (about $30 in savings). Do note, however, that soldering and organization of these boards will not be covered in the class, and if chosen by the student, will need to be managed themselves. Using such boards can also make debugging and modification significantly more time-consuming and difficult. If using StripBoard, ensure that the board's pin pitch is the standard breadboard size of 0.1" (2.54mm).

Wire Color Guide

Wire colors are used for the following, so please ensure any kit you buy contains enough of each. Wire may be available in the Electronics Lab, but gauge and color cannot be guaranteed:

Red	Power, Positive
Black	Power, Ground
White	Signal, Clock
Yellow	Signal, Control Logic
Blue	Signal, Module-to-Bus
Green	Signal, Other (IC-to-IC, Module-to-Module, etc)

Recommended Tools

Most of these tools are available in the space. However, we will need to share them within the group, as well as with others who may be working in the space at the time. Especially in the case of hand tools and multimeters, you may wish to provide your own. Given the simplicity of this project, neither high-end nor high-precision tools are required for this project.

Unless specifically marked, it is recommend that you get your own tools for this project to keep pace with the rest of the class:

Tool	Details
Flush Diagonal Cutters	Used to cut wire and trim pins flush to a surface. Very useful for any electronics project.
Self-Adjusting Wire Strippers	Used to trim the ends of wire sheathing (which we do a lot). Simpler strippers exist, if you wish to save money.
Multimeter with Standard and Alligator-Clip Probes	Used to measure voltages, amperage, continuity, and generally debug problem circuits. Given the basic nature of this project, a high-precision multimeter is not necessary
Oscilloscope	-	Used to debug and optimize circuits. We will use the Oscilloscopes in the Electronics Lab.

Authorizations

Please read the rules and responsibilities in the Electronics Area prior to attending. Along with these rules, the following authorizations must be completed to be eligible for this course:

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Syllabus

Classes are held weekly, and build on top of each other. It is important that all classes are attended, or completing the CPU will be very difficult. Office hours are made available prior to every class to allow persons who miss classes to catch up prior to starting a new lesson.

Week 1 - Digital Electronics Fundamentals

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Week 2 - Implementing Logic with Transistors

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Week 3 - The CPU Clock Module

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Week 4 - The 8-Bit Register Modules

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Week 5 - Designing an ALU

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Week 6 - The ALU Module

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Week 7 - The RAM Module

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Week 8 - Building a Binary Counter

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Week 9 - The Program Counter Module

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Week 10 - Designing for 7-Segment Displays

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Week 11 - Introduction to EEPROM

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Week 12 - The Display Module

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Week 13 - Connecting the Modules with a Bus

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Week 14 - Designing Control Signals

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Week 15 - Control Logic Module

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Completion

Upon completion, each member of the class will have a modularized, extendable CPU. The CPU can be programmed using an Arduino Programmer, which can be borrowed during the class, or built in one of the after-hours office-hours. Here are some examples what can be done to extend and modify the basic circuitry:

• Create additional circuitry to support more-advanced instructions
• Add more capabilities to the ALU to enable more-powerful processing
• Transition 7400-series integrated circuits to more-advanced functionality to reduce circuit complexity
• Extend the processing capability to 16- or even 32-bit processing
• Add additional input and output capabilities to the system (e.g., serial controllers, USB, disks, multi-line LCDs, etc...)