CVBS Video Output

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.

### 480cvbs
$ wm overscan 30,25,30,10
 
### 576cvbs
$ wm overscan 40,10,50,110