Ricoh 2A03

The Ricoh 2A03, RP2A03 (NTSC), Ricoh 2A07, RP2A07 (PAL) or 2A03 is the 8-bit microprocessor in the Nintendo Entertainment System (NES), (also known as the Famicom).

Technical details
Manufactured by Ricoh and based on the MOS Technology 6502. NTSC versions of the NES use the 2A03, which is run at 1.79 MHz. PAL versions used the 2A07 processor, which is identical to the 2A03 except that it runs at 1.66 MHz. Timing differences between NTSC & PAL versions are to ensure that the sound output is the same on either. There is no seperate soundchip. The APU, a PSG (programmable sound generator) integrated in the 2A03 is used to produce audio.