UDOO LVDS Panels

Switch video output from HDMI to LVDS

After you connect your LVDS screen to the CN13 connector, you must tell UDOO QUAD/DUAL to use the LVDS panel to draw the GUI. This can be done in several ways:

Option 1: you have an HDMI monitor and mouse/keyboard

If you have an HDMI screen connected to UDOO QUAD/DUAL, open a terminal with the link on the desktop. Then you can switch the main video output from HDMI to LVDS7 or LVDS15 by typing:

sudo udooscreenctl set lvds7
sudo udooscreenctl set lvds15

(default password, if you did not change it, is udooer)

You can revert this change by typing:

sudo udooscreenctl set hdmi

If you want more info about the udooscreenctl command visit the Set Video Output. If you prefer a graphical simple way to change the default video output, it is provided by the UDOO Web Control Panel in the "Configuration"->"Advanced setting" section.

Option 2: you can connect via VNC or SSH

If you can connect to your board via VNC or via SSH (using the USB, WiFi or Ethernet connection) , you can follow the steps explained in the previous section.

Option 3: you have neither HDMI nor network

If you cannot connect to your board via the network (VNC or SSH) and you have no HDMI screen, you can enable the LVDS display port editing a file in the UDOO QUAD/DUAL SD card. Put the flashed SD card in your computer.

A small FAT partition labelled boot will appear:

Open the file named uEnv.txt contained in the partition.

Heads up! The file must be saved with Unix-like line endings:

• Windows users can use the free Notepad++ text editor to safely edit the file.
• Mac OS X users can use the free TextWrangler text editor to safely edit the file.
• Linux users can use their favourite text editor (gedit, vim, nano) without concerns.

Open the file and, you will need to add this line (if it isn't present):

video_output=

After the = character you need to put the word hdmi or lvds7 or lvds15 for the screen you need:

video_output=hdmi
video_output=lvds7
video_output=lvds15

e.g. :

Save the file, eject the boot partition and restart the board.

Touch Calibration

if you have any problem with touch calibration try to modify the text files:

/etc/X11/xorg.conf.d/90-st1232touchscreen.conf   (for the 7" Touch Display)
/etc/X11/xorg.conf.d/91-3m_touchscreen.conf      (for the 15,6" Touch Display)

These are the default values for the 7" Touch Display:

Section "InputClass"
        Identifier "Touchscreen"
        MatchProduct    "st1232-touchscreen"
        Driver          "evdev"
        Option          "Calibration"   "3 794 476 0"
EndSection

Section "InputClass"
        Identifier      "calibration"
        MatchProduct    "3M 3M USB Touchscreen - EX II"
        Option  "Calibration"   "1853 14628 2589 14106"
        Option  "SwapAxes"      "1"
EndSection

If the calibration is not good enough you can connect a mouse to UDOO DUAL/QUAD and launch the "Calibrate Touchscreen" application from the bottom bar:

Application Menu -> System Tools -> Calibrate Touchscreen

or running in a terminal the command:

xinput_calibrator

and follow the video instruction to change your calibration.