The Ricoh 2A03 or RP2A03 (NTSC version) / Ricoh 2A07 or RP2A07 (PAL version) is the 8-bit microprocessor in the Nintendo Entertainment System video game console. It was manufactured by Ricoh. It contained a second source MOS Technology 6502 core, lacking the 6502's binary-coded decimal mode, with 22 memory-mapped I/O registers that controlled Programmable Sound Generators, rudimentary DMA, and game controller polling.
Regional variations 
European and Australian versions of the NES used the Ricoh 2A07 or RP2A07 processor, which was identical to the 2A03 except for a different clock divider and the 50 Hz vertical refresh rate used in the PAL television standard.
See also