CVBS Video Output
Hardware Example
The below picture is a sample guide.
You can find CVBS test point by header J7 near the HDMI connector.
We recommend using the board's backside point as shown in the picture. Pin 1 of header J7 can be used as a Ground point.
Software Guide (1) - Ubuntu
- Ubuntu : Available with 3.14.79-89 (Oct 13, 2016) or higher version
There are two modes of CVBS, 480cvbs and 576cvbs on C2.
You need to modify boot.ini to set CVBS output.
setenv m "480cvbs" setenv cvbsmode "480cvbs" setenv bootargs ${bootargs} cvbsmode=${cvbsmode}
And make sure the vout mode is set as hdmi mode.
setenv vout "hdmi"
Overscan
Please refer to the following article.
http://magazine.odroid.com/wp-content/uploads/ODROID-Magazine-201602.pdf#page=9
As we tested cvbs mode with our monitors, overscan setting is needed.
For example, in case of 480cvbs mode, the following values can be used.
# echo 20 20 695 478 > /sys/class/graphics/fb0/window_axis # echo 0x10001 > /sys/class/graphics/fb0/free_scale
Software Guide (2) - Android
- We're planning to release CVBS functionality soon. The version will be specified here after new release.
Please refer to the following example.
setenv hdmimode "480cvbs" setenv cvbs "480cvbs" # Display Auto Detection # "false" or "true" setenv display_autodetect "false" setenv bootargs "${rootopt} ${consoleopt} hdmimode=${hdmimode} cvbs=${cvbs} ${cmode} ${hdmitx} vout=${vout_mode} disablehpd=${disablehpd} logo=${logoopt} ${androidopt} ${selinuxopt} suspend_hdmiphy=${suspend_hdmiphy} led_onoff=${led_onoff} max_freq=${max_freq} maxcpus=${maxcpus} disable_vu7=${disable_vu7} touch_invert_x=${touch_invert_x} touch_invert_y=${touch_invert_y} usbmulticam=${usbmulticam} gpiopower=${gpiopower} backlight_pwm=${backlight_pwm} ddrclock=${ddrclock} test_mt_pid=${test_mt_pid} test_mt_vid=${test_mt_vid}"
Overscan
As we tested cvbs mode with our monitors, overscan setting is needed. For example, the following values can be used.
- target
### 480cvbs $ wm overscan 30,25,30,10 ### 576cvbs $ wm overscan 40,10,50,110