The '''MOS Technology 6502''' is an 8-bit microprocessor designed by Chuck Peddle for MOS Technology in 1975. When it was introduced it was the least expensive full featured CPU on the market by far, at about 1/6th the price, or less, of competing designs from larger companies such as Motorola and Intel. It was nevertheless faster than most of them, and, along with the [[Zilog]] [[Z80]], sparked off a series of computer projects that would eventually result in the home computer revolution of the 1980s. The 6502 design was originally second-sourced by Rockwell and Synertek and later licensed to a number of companies; it is still made for embedded systems.
The 6502 was used, among others, for Commodore's 8-bit machines.
Originally the CPC was destined to be designed around the 6502 processor. But when Amstrad approached [[Locomotive Software]] to develop a Basic for it with a very tight deadline, Locomotive PLC, who already had a Z80 Basic in the works, urged and convinced Amstrad to switch to the Z80.
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== Description ==
The 6502 microprocessor is an 8-bit CPU with an 8-bit ALU and a 16-bit address bus capable of direct access to 64KB of memory space. Like the Z80, the 6502 is also a little-endian CPU, meaning it stores 16-bit values with the least significant byte first, followed by the most significant byte. The 6502 has 151 instructions, which are composed of 56 distinct opcodes across various addressing modes.
While it doesn't match the raw power of processors like the Intel 80x86 or the Motorola 68000 series, the 6502 is widely known for its efficiency and low cost, making it ideal for embedded systems and early home computers. Its simple design allowed for reduced manufacturing costs and ease of implementation.
The 6502 comes in a 40-pin DIP package. It has been produced by various manufacturers and used in a wide range of applications, from early gaming consoles like the Nintendo Entertainment System to personal computers like the Apple II and Commodore 64.
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