VID(3)                      (MPC823)                       VID(3)

     NAME
          vid - Motorola 823 video output

     SYNOPSIS
          bind -b #v /dev

          /dev/viddata
          /dev/vidctl
          /dev/vidcram

     DESCRIPTION
          The vid device serves two files giving basic access to the
          on-chip video output of the Motorola 823.  It assumes a
          video hardware configuration exactly like that of the
          823FADS board, with an I²C interface to an off-chip ADV7176
          NTSC/PAL converter at I²C address 0x54.

          The control device vidctl accepts the following commands:

          on   Disable LCD panel (if present) and enable output from
               the video frame buffer.

          off  Stop display from the video frame buffer and re-enable
               the LCD panel (if present).

          mode m
               Set the video output format to m, which is one of:
               ntsc, pal-i, pal-m or pal-n.  This command is only
               effective when video output is off.  When next switched
               on, the both the video controller RAM and ADV7176 are
               reprogrammed to the new format.

          Video data can be written to the video frame buffer by
          writes of the viddata file.  The file offset selects the
          starting byte within the frame buffer.  Reads return the
          corresponding data from the frame buffer.  The application
          is responsible for formatting the data as the 823's video
          encoder requires, for the selected video format.

          The file vidcram gives read and write access to the contents
          of the video control RAM.  The file offset addresses bytes
          in the RAM; values can be read from or written to the RAM in
          groups of 4-byte big-endian words.

     SOURCE
          /os/mpc/devvid.c

     BUGS
          Square pixel mode cannot be used on the FADS board: no suit-
          able video clock source is available.