Looking at the 6502 processor you must come to the conclusion that it is a very Spartan piece of equipment. To the letter it is not RISC but it comes close, many things other processors have are not present in the 6502. The simplicity made it easier to work with and that is what made it loved by millions of users, but after a while the lack of speed and the absence of real IO made the 6502 not ready for the future. The Z80 lived longer and had more offspring. Only the 6800 and the 8008 have evolved into modern chips still available today. If I would have been on the team of designers I would have made it different. First of all I would give the 6502 ordinary IO, then I would make the addressability bigger and I would give it strictly separated program-memory and data-memory. (for safety) Dozens of chips all working in their own program-memory could function together with other processors on the same sheared data-memory. If in the '70's the Von Neumann-principle was put to rest we would have skipped at least 50 years of useless developments.

Maybe because the X and Y registers were "designed" for indexing data and stepping up and down was considered important? Never quite got my head around 6502 beyond having a basic understanding of the instructions, despite even writing a disassembler WAY back in the past (and one for the related 65816). Maybe because I learned Z80 first which spoils you for registers... It's great seeing these sorts of projects involving these classic CPUs... I really enjoyed getting down to the bits in the 80s and early 90s on Z80 and 68000, less so on 8086 and 6502... I feel inspired to play with this sort of stuff myself, and it is amazing to think that 6502 and Z80 chips can still be bought new!

Simple; 1) you can increase the Accumulator with CLC ADC #$01 and, 2) The X/Y registers are used to index into memory for the more complicated addressing modes, but the Accumulator is not used to index into memory, so the designers saw no point in wasting more silicon with an implementation to increment or decrement it. That’s my guess, but you’d have to ask the actual designers, assuming any are still alive. 🤔

best name EVER!!!!

Man, all I did during the lockdown was organize my closets. I feel like a failure! LOL.

That's a cool display. Where did you get it from?

Did you think about ordering the necessary components from companies like DigiKey or Mouser? Anyway, keep up the excellent work!