I bought a cute little 4 bit cpu kit from Aliexpress called the TD4. It has 2 registers, some LEDs, and 16 bytes of program ROM. Quite limited but still very cool and teaches a lot of principles of computer architecture. The documentation, schematics, and pictures for this cpu are here https://github.com/wuxx/TD4-4BIT-CPU. It’s a little sparse though. I can imagine a student getting overwhelmed. So I thought it would be helpful to write some longer form notes. Building We took two sessions just.