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Changing the Video Input/Output Methods
A-2
A.1 Changing the Video Input/Output Methods
U-Boot reads the S3 mini-dip switch, position 10 setting on boot-up and
stores the results in the videostd environment variable. As long as your
U-Boot bootcmd sets the video output using the videostd variable (as the
example bootcmds in Section A.4, Alternate Boot Methods do), you can
switch between NTSC and PAL by simply changing the S3 switch setting
as shown in Section 2.1, Setting Up the Hardware.
To automatically update the bootargs based on the S3 switch setting,
please use the following options:
EVM # setenv bootargs 'mem=232M console=ttyS0,115200n8
root=/dev/mtdblock0 rw rootfstype=yaffs2 ip=dhcp
video=davincifb:vid0=0,2025K:vid1=0,
1350K:osd0=720x576x16,
2025K davinci_enc_mgr.ch0_output=COMPOSITE
EVM # setenv bootcmd 'setenv setboot setenv bootargs
\$(bootargs) davinci_enc_mngr.ch0_mode=\$(videostd);run
setboot;nboot 0x80700000 0 0x400000;bootm'
If you do not want to use the videostd variable in your bootcmd, use the
following options within your bootargs setting. The difference between
the NTSC and PAL settings is shown in bold.
NTSC
video=davincifb:vid0=0,2025K:vid1=0,
1350K:osd0=720x576x16,
2025K davinci_enc_mgr.ch0_output=COMPOSITE
davinci_enc_mgr.ch0_mode=ntsc
PAL
video=davincifb:vid0=0,2025K:vid1=0,
1350K:osd0=720x576x16,
2025K davinci_enc_mgr.ch0_output=COMPOSITE
davinci_enc_mgr.ch0_mode=pal