Ricoh 2A03

Ricoh 2A03 / Ricoh 2A07

Produced	From 1982 to 1994
Common manufacturer(s)	Nintendo, Ricoh
Max. CPU clock rate	1.79 MHz
Min. feature size	6 μm
Instruction set	MOS 6502
Cores	1
Socket(s)	Through-hole Dual Inline Package (DIP)

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 manufactured by Ricoh. It contained a second source MOS Technology 6502 core, modified to disable the 6502's binary-coded decimal mode, with 22 memory-mapped I/O registers that controlled an APU, rudimentary DMA, and game controller polling. It was also used as a sound chip and secondary CPU by Nintendo's arcade games Punch-Out!! and Donkey Kong 3.

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, with the exception of the 16 hard-coded sampling rates for the Delta modulation-encoded sample playback unit. The changes were made in order for sampled sounds to maintain the original pitch of the RP2A03 with the new clock divider.

See also

• Nintendo Entertainment System technical specifications