it;s not the same cpu , it has got rid of decimal mode and has got instructions for gfx and sound but I'm not keen on it , see http://nesdev.parodius.com/
owns 1xC128, 1x128D cr ,1xc64 (broken unfortunately) ,1xc64c ,2xc64g (one is broken) ,~4xc64e ,1x1541 ,1x1541-II ,1x1541C and some chips for those machines
The main processor used in the NES is the Ricoh RP2A03G, a 6502 variant with built-in audio processing capabilities, and which lacks the Binary Coded Decimal mode. As far as I know, the 2A03 and 6502 are otherwise identical. Graphics are generated by the RP2C02G co-processor, otherwise known as the Picture Processing Unit (PPU).
The 2A03 also has some a couple DMA features. One copies a page of memory to the PPU's OAM (object attribute memory), which takes 2 CPU cycles per byte. The other DMA is used for playing delta-modulated samples. The registers for the internal stuff are all at $4000-$4017