NOTICE: The Processors Wiki will End-of-Life in December of 2020. It is recommended to download any files or other content you may need that are hosted on The site is now set to read only.

DM355 EVM PAL/NTSC selection

From Texas Instruments Wiki
Jump to: navigation, search

The Video drivers require the secondary bootloader (U-Boot) to pass the output mode (NTSC or PAL) as an argument in the commandline to the kernel. This is done by updating the bootargs environment variable.

The Jumper J1 on the DM355 EVM decides the output mode selection. U-Boot detects the jumper position and sets the output mode selection as NTSC or PAL using an environment variable - videostd.

When you execute 'printenv' at the U-Boot prompt, you will notice the value of videostd changing based on the jumper selection.




In order to pass this value automatically (when ever the jumper position is changed), the following environment variables need to be updated:

setenv bootargs 'mem=116M console=ttyS0,115200n8 root=/dev/mtdblock3 rw rootfstype=yaffs2 ip=dhcp'
setenv bootcmd 'setenv setboot setenv bootargs \$(bootargs) video=dm355fb:output=\$(videostd);run setboot;nboot 0x80700000 0 0x400000;bootm'

On every reboot, the bootcmd updates the bootargs with the current videostd setting.

Note: These settings are valid with the Beta release version of DVSDK 1.30 (and the corresponding LSP)