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.
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