VID(3)VID(3)NAMEvid - 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 configu‐
ration 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 out‐
put is off. When next switched on, the both the video con‐
troller 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 buf‐
fer. 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 suitable video
clock source is available.
MPC823 VID(3)
