Motherboard
The motherboard is the brain of the console, and serves as the base for all other console components, including integrated circuits, connector ports, A/V output, and power.
Primary Components
CPU
The NEC VR4300 serves as the CPU, which runs at 93.75 MHz. It contains a 64 bit bus internally, a 5-stage pipeline, 24KB of L1 cache, and a 64 bit FPU used for floating point operations.
Reality CoProcessor
The RCP is effectively the console's GPU. So named as it contains two processors: the Reality Display Processor, and the Reality Signal Processor. However, it also manages memory access to and from the CPU, as there is no direct connection between the CPU and console memory.
Video Interface
The video interface is made up of multiple components, including the Video DAC and a video encoder chip, but most of the interface is implemented inside the RCP. The interface handles the graphics output from the RCP and feeds it to the console's Composite and S-Video outputs.
Controller Ports
Four controller ports are found along one side of the motherboard. While they are most often used for standard controllers, they can be used for any Joybus device. Custom devices can even be produced to enable additional functionality for games. The Voice Recognition Unit is one official example of such a device. These devices can either use existing Joybus commands or games can define their own for communicating different information.