MOS 6502

A MOS 6502 chip.

The MOS 6502 is an 8-bit microprocessor designed by Chuck Peddle and a team of engineers at MOS Technology and released in 1975. It's design was largely based on the Motorola 6800, but simplified to be cheaper and faster, and was usually employed as a central processing unit. It has an instruction set of 56 8-bit instructions across 151 opcodes, has a 16-bit address bus, can be clocked from 1-3 MHz, and is packaged in a 40-pin DIP, initially in ceramic. Because it was so cheap to produce, the processor was one of the most popular chips for home computers and video games from the late 1970s through the 1980s and is still used in embedded systems to this day. Unlike the competing Intel design, the 6502 used a RISC philosophy (even before the term was used).

Personal

I didn't start learning about the 6502 until after I began playing with the debugger of a NES emulator. With it, I began teaching myself about 6502 machine language. I'm still quite terrible at it, but I known enough to read and modify basic programs.

Devices

There are a couple dozen devices which use the 6502 and its variants, but here are the most popular ones:

Device	Released	CPU Type
Apple I	1976-04-11	6502
Apple II family	1977-06-10	6502
Atari 2600	1977-09-11	6507
Atari 5200	1982-11-??	6502C
Atari 8-bit family	1979-11-??	6502B or 6502 SALLY
Atom	1980-03-??	6502
BBC Micro	1981-12-??	6502A
Commodore PET	1977-10-??	6502
Commodore VIC-20	1980-??-??	6502
Commodore 64	1982-08-??	6510
Commodore 128	1985-??-??	8502
Commodore Plus/4	1984-??-??	7501
Electron	1983-08-25	Synertek SY6502A
Famicom	1983-07-15	Ricoh 2A03
Lynx	1989-09-??	VLSI VL65NC02
Nintendo Entertainment System	1985-10-18	Ricoh 2A03
PlayChoice-10	1986-??-??	Ricoh 2A03
TurboGrafx-16	1987-10-30	Hudson Soft HuC6280
VS. System	1984-??-??	Ricoh 2A03