Nintendo Entertainment System

The heart of the NES is the Ricoh 2A03, a modified MOS 6502 processor that lacked the decimal mode but integrated a custom Audio Processing Unit (APU). This 5-channel APU (2 pulse, 1 triangle, 1 noise, 1 DPCM) is responsible for the distinct "8-bit" sound that defined the era. The Picture Processing Unit (PPU) was equally capable, managing sprites and scrolling backgrounds with a level of fluidity that competitors like the Commodore 64 struggled to match.