MOS 6502
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. It has an instruction set of 56 8-bit instructions with 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:
- Apple I
- Apple II family
- Atari 2600
- Atari 8-bit family
- Atom
- BBC Micro
- Commodore PET
- Commodore VIC-20
- Commodore 64
- Commodore 128
- Commodore Plus/4
- Electron
- Famicom
- Lynx
- Nintendo Entertainment System
- PlayChoice-10
- TurboGrafx-16
- VS. System
A 16-bit version of the 6502 was created in 1983 and variations were used in the Apple IIgs and Super Nintendo Entertainment System.
Media
Pictures
A MOS 6502.
The exposed die.
Documentation
6500 Family Programming Manual.
Pinout.
Videos
Links
- 6502.org - The 6502 Microprocessor Resource.
- skilldrick.github.io/easy6502 - An online 6502 emulator.
- visual6502.org - Reverse engineering the 6502.
