Ricoh 2A03

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RP2A03E
RP2A07

Ricoh 2A03 or RP2A03 is the NTSC version of the 8-bit microprocessor of the Nintendo Entertainment System (NES) game console , manufactured by Ricoh . It contained a 6502 core from a secondary source that lacked the BCD code mode of the 6502. To control the programmable tone generators it had 22 memory mapped I / O registers, rudimentary DMA and polling for the game controller .

Regional variants

European and Australian versions of the NES used the Ricoh 2A07 - or RP2A07 processor, which is identical to 2A03, up to another frequency divider and different low frequency - lookup tables to the 50 Hz vertical frequency to determine that the PAL used standard .

See also

Individual evidence

  1. ↑ Brad Taylor: 2A03 technical reference. April 23, 2004, accessed June 6, 2008 .