Ricoh 2A03

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 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.cite web|url=http://www.nesdev.com/2A03%20technical%20reference.txt|title=2A03 technical reference|last=Taylor|first=Brad|date=2004-04-23|accessdate=2008-06-06]

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 different audio frequency lookup tables to account for the 50Hz vertical refresh rate used in the PAL television standard.

ee also

* Nintendo Entertainment System technical specifications

References