Video DAC

The video DAC is connected to the RCP over a video bus. The Video Interface (VI) sends data to the video DAC from the framebuffer. The video bus is one (7-bit) byte wide and also has a !DSYNC signal. The !DSYNC signal is active on the first out of four bytes. The bus comes out of the RCP and is fed into the video DAC. A clock signal (about 50Mhz) is also connected to the DAC. Only NTSC supports s-video. The control deck can be modified to suport RGB as this was left unconnected in the retail.

Pinout:
--          --    |                    |              OSC (~50Mhz)
 * D0||       | composite video
 * D1||       |
 * D2||       |
 * RCP  D3||  DAC   | luma (s-video)
 * D4||       |
 * D5||       |
 * D6||       | chroma (s-video)
 * !DSYNC||       |
 * clock|---+|       |
 * clock|---+|       |