27c3: Reverse Engineering the MOS 6502 CPU (en)

It used the MOS 6502 CPU, which was also used for the Apple I, Apple II, the Commodores and Atari and Nintendo (NES, SNES) game consoles! ▶ this video link link

Here's a nice talk video covering the story from the origins of the 6502 to the Visual 6502 (but not the wasm Remix): ▶ this video .

If you have no experience in digital electronics at all, I would actually start with a book like Code by Charles Petzold. It's a pop-science book about electronics and goes from light bulbs and switches to simple logic blocks like adders. It covers the basic building blocks of virtually every cpu in existence - how to turn transistors into calculators. It's well written and provides some context to otherwise pretty dry textbooks. There is quite a bit of difference between how an FPGA works and is programmed versus a totally custom chip. You could also take a look at reverse engineering walkthroughs eg Ken Shirrif has a few on his blog. Nand2tetris is another good thing to look at. Finally, reverse engineering the MOS6502: ▶ this video

There's a lot of information about reverse engineering some of the older CPUs around e.g. the MOS6502 (NES, Apple II, C64, etc). This is a great presentation showing how this CPU is reverse engineered: ▶ this video Basically it comes down to the fact that you can't really hide transistors and ultimately that's something you can reconstruct. It sounds like a lot of work, and it is, but if you do it you can perfectly emulate a chip. If you can dig out non volatile memory then potentially you have the firmware. Once someone has their hands on that it'll be broken, almost guaranteed, as it becomes a software problem. Lots of people are very good at assembly hacking.