MOS Technology 6502

Short history

MOS Technology, Inc was a company specialised in semiconductor design and fabrication. It is most well known for the MOS 6502 that was designed by Chuck Peddle and Bill Mensch. It was released in 1975 and is a big contributor to the home computer revolution in the 1980s.

Notable home computers that used this processor include the Atari 8-bit models, Apple II, Commodore 64, Nintendo Family Computer (Famicom) and Entertainment System (NES). It also functions as the blueprint for the subsequent development of 16-bit processors that were used in Nintendo’s Super Nintendo Entertainment System (SNES).

Features

  • 8-bit data bus (D0-D7)
  • 16-bit address bus (A0-A15; 64 KiB memory space)
  • 8-bit ALU (carry, negative, overflow, zero)
  • 8-bit accumulator (A)
  • 8-bit stack pointer (S)
  • 8-bit index registers (X and Y)
  • 8-bit processor status register (P)
  • 16-bit program counter (PC)
  • 16 addressing modes

Functional description

Arithmetic and Logic Unit (ALU)

Status flags supported:

  • Carry (C)
  • Negative (N)
  • Overflow (V)
  • Zero (Z)

Specifications

CPU clock rate:1 MHz to 2 MHz
Operating voltage range:1.8 V, 2.5 V, 3.0 V, 3.3 V, 5.0 V
Power consumption:150 µA @ 1 MHz
Package:40-pin DIP

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