A Homemade TTL 6502 (20MHz) - by Drass (WoC 2018)

Great presentation by Drass - first foray into hardware, first PCB design, first soldering, and he made a 20MHz plug-compatible 6502 out of TTL. Lots of TTL. And then ramped the voltage up to overclock it.

The project has its own website (and datasheet!):

via the project’s own megathread on the 6502.org forums.


I like this project because he actually put it in circuit in a machine and it worked. I’ve seen lots of projects that make “giant” all discreet versions of chips, including things like the 555 timer, and I’ve always wondered if anyone put these in circuit. Now I see someone has.

I’m pretty sure the MOnSter6502 has run in-circuit, but not at 1MHz (let alone 20MHz!)… oh yes, it’s run in/with the Cactus computer. But to run at full speed, and with exact cycle timing, including undocumented instructions, as the C74-6502 does, that’s something else.