Input / Output

The Nintendo 64 system spends a good deal of its time performing I/O operations. The operating system provides an optimized I/O interface layer that directly communicates with the hardware. Some of these interfaces include:

- VI — the video interface
  The interface routines communicate with a video manager system thread, called the VI/Timer manager. This thread receives all vertical retrace interrupts and programs the video hardware. In addition, it also receives all counter interrupt messages and implements timer services.

- PI — the peripheral interface
  The PI also has an associated I/O manager thread, the PI manager. It manages access to the ROM cartridge so that two threads do not attempt to DMA from ROM to RAM at the same time.

- AI — the audio interface
  This interface programs the audio hardware to output the desired sample rate and manages access to the audio data buffer.

- DP — the RDP interface
  It is mostly of interest because it has an associated system event when a DP operation is complete.

- Cont — the controller interface
  This interface resets, detects, obtains status, queries and reads data from the game controllers.

Copyright © 1999 Nintendo of America Inc. All Rights Reserved Nintendo and N64 are registered trademarks of Nintendo Last Updated January, 1999