1) It's still simple enough that you can actually get a full diagram of the processor and actually have hope of understanding it.
2) It's interesting enough to actually produce good things. Blockbusters like Super Mario Bros 3 were based on this tech. The Terminator runs on the 6502. The low-cost CPU was comparatively as ubiquitous as the Intel architecture is today.
3) Limitations breed creativity and ingenuity. When you only have uint8 as your only data type, the kind of tricks you have to do to get a simple physics engine working are very interesting.
https://www.youtube.com/watch?v=9UP7HImbAlA&t=517s
So combined with not-too-complicated but complicated-enough-to-be-useful is basically why old tech is fun.
The 6502 in particular is a nice choice since they're still made and available (Mouser carries them), there's a zillion vintage things that use them if you want something actually old, there's hobbyist kits/preassembled if you want something new, and it's a super easy CPU to interface to, especially for trivial cases.
And you can still get them today... and they're still in fairly wide use. https://westerndesigncenter.com
> The legendary 6502/65816 microprocessors with both 8-bit and 8/16-bit ISA's keep cranking out the unit volumes in ASIC and standard microcontroller forms supplied by WDC and WDC's licensees. Annual volumes in the hundreds (100's) of millions of units keep adding in a significant way to the estimated shipped volumes of five (5) to ten (10) billion units. With 200MHz+ 8-bit W65C02S and 100MHz+ 8/16-bit W65C816S processors coming on line in ASIC and FPGA forms, we see these annual volumes continuing for a long, long time.
> The 6502 is likely the only processor family that has remained loyal to its ISA over the last 45 years. In addition it has served the widest spectrum of electronic markets through those years. For example, it has served and in some cases created markets for the PC, video game, toy, communication, industrial control, automotive, life support embedded in the human body medical devices, outside the body medical systems, engineering education systems, hobby systems, and you name it electronic market segments. I might add the 6502 has served in a highly reliable and successful way!
> As added food for thought, the 6502/65816 microprocessors protect millions of lives annually within embedded heart defibrillation and pacing systems. We are quite proud of what our customers and partners have created and continue to create with the 6502 Embedded Intelligence Technology for the benefit of mankind!
Another fun fact: the most common CPU in use today is the Z80 (or at least it was a couple of years ago, I haven't checked since). 6502s are not rare. In both cases, they may go by different part numbers these days, of course.
Where I work, I'm currently working on a system that uses 6 Z80s.
Z80s are used here because they're tiny, low-power, cheap, readily available from multiple manufacturers (a particular bonus since the chip shortage remains a problem), and are extremely reliable. A more modern CPU would be more expensive and harder to guarantee behavior in.
There’s even a Turbo Pascal-like IDE that can target them. Link: https://retrogamecoders.com/introduction-to-trse-programming...
Ahem! uint8 or int8 by the programmers discretions that is.