History and use of 6052

The 6502 was designed primarily by the same engineering team that had designed the Motorola 6800. After resigning from Motorola en masse, the team went looking for another company that would be interested in hosting a design team, and found MOS Technology, then a small chipmaking company whose main product was a single-chip implementation of the popular Pong video game.

At MOS, they quickly designed the 6501, a completely new processor that was pin-compatible with the 6800 (that is, it could be plugged into motherboards designed for the Motorola processor, although its instruction set was different). Motorola sued immediately, and MOS agreed to stop producing the 6501 and went back to the drawing board. The result was the "lawsuit-compatible" 6502, which was by design unusable in a 6800 motherboard but otherwise identical to the 6501. Motorola had no objection. However, this left MOS with the problem of getting developers to try their processor, so engineer Peddle designed the KIM-1 simple single-board computer. Much to their surprise, the KIM-1 sold well to hobbyists and tinkerers as well as to the engineers it was intended for. The related Rockwell AIM 65 control/training/development system also did well. Another roughly similar product was the Synertek SYM-1.


Apple IIeThe 6502 was introduced at $25 at the Westcon show in September 1975. The company had an off-floor suite with a wooden barrel full of the chips, although this early run meant only the ones at the top of the barrel worked. At the same show the 6800 and Intel 8080 were selling for $179. At first many people thought the new chip's price was a hoax or a mistake, but while the show was still ongoing both Motorola and Intel had dropped their chips to $79. These price reductions legitimized the 6502, which started selling by the hundreds.

One of the first "public" uses for the design was the Apple I computer, introduced in 1976. The 6502 was next used in the Commodore PET and the Apple II. It was later used in the Atari home computers, the BBC Micro family, the Commodore VIC-20 and a large number of other designs both for home computers and business, such as Ohio Scientific.


Commodore 64The 6510, a direct successor of the 6502 with a digital I/O port and a three-state address bus, was the CPU utilized in the Commodore 64 home computer. (Commodore's disk drive, the 1541, had a processor of its own—it too was a 6502.)


Atari 2600Another important use of the 6500 family was in video games. The first to make use was the Atari 2600 videogame console. The 2600 used an offshoot of the 6502 called the 6507, which had fewer pins and, as a result, could address only 8 KB of memory. Millions of the Atari consoles would be sold, each with a MOS processor. Another significant use was by the Nintendo Famicom, a Japanese video game console. Its international equivalent, the Nintendo Entertainment System, also used the processor. The 6502 used in the NES was a second source version by Ricoh, a partial system-on-a-chip, that lacked a binary-coded decimal mode but added 22 memory-mapped registers for sound generation, joypad reading, and sprite list DMA. Called 2A03 in NTSC consoles and 2A07 in PAL consoles (the difference being the memory divider ratio and a lookup table for audio sample rates), this processor was produced exclusively for Nintendo.

Even as of 2006, some universities, including the Eindhoven University of Technology, the Netherlands, University of Tasmania, the University of Applied Sciences in Cologne, Germany, University of Exeter in Devon, England, Carleton College, Hull University, Matthew Boulton College, University of Brescia in Italy and Universidad APEC in Santo Domingo, Dominican Republic still use the processor to teach assembly language, computer architecture and digital integrated systems.