YURIX


Building a CPU - 50% through the project

Summer 2023

The breadboard CPU I built

As part of my education, I have to do a bigger project before finishing school. I've always been very interested in computer architecture and design, so I decided to combine the two: Build a CPU as a project.

This is obviously an ambitious project, additionally because I didn't just want to build the simplest things possible. And this is already the most important advice I can give to anyone: Keep it as simple as possible. And if you think it is simple enough, make it 10 times simpler.

Anyways, how does one actually build a CPU? Producing your own chip is pretty much out of question, the cost are way to high. For example, the semiconductor prototyping platform efabless.com lists a price of only 10'000$.

Since I want a real product and not just a simulation in something like an FPGA, I decided to build the thing using 74-Series glue-logic integrated circuits. They are great. To connect them, I use breadboards and wire.

A 74-Series integrated circuit as a PDIP chip

However, I mainly wanted this post to be about my learnings. Here is a list

Maybe one day I'll write about the details of the architecture of a CPU, but until then, these are my experiences I wanted to get out and share with the wild. On James Sharmann's discord from time to time people ask questions that exactly need this kind of answer, so I hope it helps ¯\_(ツ)_/¯.