6502 compatible TTL computer

So, this is the project I've been working on for the past 10 months, a 6502 compatible (but for timing and decimal mode) TTL CPU and accompanying computer.

I'm slowly working my way through Learning the Art of Electronics, and the digital part of the course requires quite a lot of specialized material. To make up for the practical sessions, I decided to build a CPU from 74XX ICs. The original idea was to make something like this project , but then I found out about the 6502 and things went a bit out of hand.

I started designing the CPU in Logisim, using Python to write microcode and the ALU ROMs contents. After several versions and a lot of debugging, it finally executed Klauss Dorman's 6502 test suite, taking an entire week to do so in the slow Logisim simulation.

Most schematics were laid out and the entire CPU was built in little more than two weeks, on "holidays" between university semesters. Quite some productive time I must say.

Lots of debugging and modifications later, regarding subjects such as power and ground distribution, reflections, asynchronous interrupts and more, the CPU and the peripherals I have built around are now fully functional.

Those peripherals include memory, a character LCD, VGA output, PS/2 and serial interface.

All this was possible thanks to the people over forum.6502.org. This project's thread can be found here.

All files, schematics, block diagrams, assembly programs, the Logisim simulation and more can be found in this gitHub repository.

Finished case

Fully populated CPU cards

This is just a short summary. I may write a couple posts on curious aspects of the project. As of now, here is a summary & demonstration video:

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