Qué (quién) es 6502 - definición

8-BIT MICROPROCESSOR

MOS Technology 6501; 6502 microprocessor; 6502; 6501; MOS Technologies 6501; MOS Technologies 6502; M6502; MOS 6502; Motorola M6502; Sunplus Technology SPLB20D2; SPLB20D2; 6502 architecture computer; 6502 Processor; CM630; 6502 assembly; MOS Technology 6502C; MOS 6502C; 6502C; SALLY (microprocessor); MOS 6512; 6502A; MOS Technology 6512

Home computers and video game consoles using the 6502 or its variants

6502

<hardware> An eight-bit microprocessor designed by {MOS Technologies} around 1975 and made by Rockwell. Unlike the Intel 8080 and its kind, the 6502 had very few registers. It was an 8-bit processor, with 16-bit {address bus}. Inside was one 8-bit data register (accumulator), two 8-bit index registers and an 8-bit stack pointer (stack was preset from address 256 to 511). It used these index and stack registers effectively, with more addressing modes, including a fast zero-page mode that accessed memory locations from address 0 to 255 with an 8-bit address (it didn't have to fetch a second byte for the address). Back when the 6502 was introduced, RAM was actually faster than CPUs, so it made sense to optimise for RAM access rather than increase the number of registers on a chip. The 6502 was used in the BBC Microcomputer, Apple II, Commodore, Apple Computer and Atari {personal computers}. Steve Wozniak described it as the first chip you could get for less than a hundred dollars (actually a quarter of the 6800 price). The 6502's indirect jump instruction, JMP (xxxx), was broken. If the address was hexadecimal xxFF, the processor would not access the address stored in xxFF and xxFF + 1, but rather xxFF and xx00. The 6510 did not fix this bug, nor was it fixed in any of the other NMOS versions of the 6502 such as the 8502. Bill Mensch at Western Design Center was probably the first to fix it, in the 65C02. The 6502 also had undocumented instructions. The 65816 is an expanded version of the 6502. There is a 6502 assembler by Doug Jones <jones@cs.uiowa.edu> which supports macros and conditional features and can be used for linkage editing of object files. It requires Pascal. See also cross-assembler, RTI, Small-C. (2001-01-02)

6501

<hardware> An eight-bit microprocessor, the first sold by MOS Technologies. The 6501 pin-compatible with the Motorola 6800 and was the first member of the 650x series. It had an on-chip clock oscillator. See also 6502. (2001-02-26)

Wikipedia

MOS Technology 6502

The MOS Technology 6502 (typically pronounced "sixty-five-oh-two" or "six-five-oh-two") is an 8-bit microprocessor that was designed by a small team led by Chuck Peddle for MOS Technology. The design team had formerly worked at Motorola on the Motorola 6800 project; the 6502 is essentially a simplified, less expensive and faster version of that design.

When it was introduced in 1975, the 6502 was the least expensive microprocessor on the market by a considerable margin. It initially sold for less than one-sixth the cost of competing designs from larger companies, such as the 6800 or Intel 8080. Its introduction caused rapid decreases in pricing across the entire processor market. Along with the Zilog Z80, it sparked a series of projects that resulted in the home computer revolution of the early 1980s.

Popular video game consoles and home computers of the 1980s and early 1990s, such as the Atari 2600, Atari 8-bit family, Apple II, Nintendo Entertainment System, Commodore 64, Atari Lynx, BBC Micro and others, use the 6502 or variations of the basic design. Soon after the 6502's introduction, MOS Technology was purchased outright by Commodore International, who continued to sell the microprocessor and licenses to other manufacturers. In the early days of the 6502, it was second-sourced by Rockwell and Synertek, and later licensed to other companies.

In 1981, the Western Design Center started development of a CMOS version, the 65C02. This continues to be widely used in embedded systems, with estimated production volumes in the hundreds of millions.

https://en.wikipedia.org/wiki/MOS Technology 6502