Ricoh 2A03

Ricoh 2A03 / Ricoh 2A07

General information
Launched	1982
Discontinued	2003
Common manufacturer(s)	Nintendo, Ricoh
Performance
Max. CPU clock rate	1.79 MHz
Architecture and classification
Technology node	6 μm
Instruction set	MOS 6502
Physical specifications
Cores	1
Socket(s)	Through-hole Dual Inline Package (DIP)

RP2A03E

The Ricoh 2A03 or RP2A03 (NTSC version) / Ricoh 2A07 or RP2A07 (PAL version) is an 8-bit microprocessor manufactured by Ricoh for the Nintendo Entertainment System video game console. It was also used as a sound chip and secondary CPU by Nintendo's arcade games Punch-Out!! and Donkey Kong 3.

Technical details

The Ricoh 2A03 contained a second sourced MOS Technology 6502 core, modified to disable the 6502's binary-coded decimal mode (possibly to avoid a MOS Technology patent). It also integrated a programmable sound generator (also known as APU, featuring twenty two memory-mapped I/O registers), rudimentary DMA, and game controller polling.

Regional variations

PAL versions of the NES (sold in Europe, Asia, and Australia) 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