Enable Capacitive touch display 10.1" LVDS on Apalis Evaluation Board

Dear developer,
I have the following configuration:
-apalis eval board V1.1z
-imx8 quadmax 8gb v1.1a
-calacitive touch display 10.1 lvds v1.0a (the display is connected to the x13 connector of the card; I have not connected the touch adapter v1.0a)

I connected the card to a monitor via DVI connection

I connected the card to the network

I connected the card to the PC via USB cable (I have the commercial version of QT on my PC)

My goal is to configure the system to be able to create applications with the QT, download them to the toradex card, view the information on the toradex touch display.

Problem: When I start the Apalis card, I cannot view the information via the toradex touch display.

I booted the board with 12V power, downloaded qt for Device Creation Demo Image to the Apalis board.

I started Qt, created a new project (a simple Button). I clicked Run to launch the application.
This button appeared on the monitor with DVI connection AND NOT ON THE TORADEx TOUCH DISPLAY (on the x39 and x40 connector the jumpers are positioned on DVI)
By positioning the x39 and x40 connector jumpers in correspondence with LVDS and starting the toradex card, the information is always displayed on the monitor connected to the DVI and not via the touch display.

How can I solve the problem?

Tanks for your support

Hi, I’m the Toradex AI Assistant. I’m in early beta, and I would appreciate your feedback.
The Toradex Support team will follow up with you shortly!

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To address the issue where your Apalis iMX8 QuadMax module is not displaying output on the capacitive touch display connected via LVDS, but instead on a monitor connected via DVI, you’ll need to ensure that the display settings are correctly configured to route the video output to the LVDS display. Here are the steps you should follow:

  1. Ensure Hardware Connections: Verify that the LVDS display and the capacitive touch adapter are correctly connected as per the instructions you’ve followed. Since you mentioned not connecting the touch adapter, please ensure it’s connected if touch functionality is required.

  2. Check the Device Tree: The display output is controlled by the device tree settings on the Apalis iMX8. You’ll need to modify the device tree to ensure that the LVDS display is enabled and configured as the primary display output. Look for the display-related nodes in the device tree and adjust them to match your LVDS display specifications. This might involve specifying the correct resolution, timings, and interface type for the LVDS display.

  3. Update the Bootloader Environment: The U-Boot environment variables might also need to be adjusted to select the correct display output. You can change the display output settings by modifying the vidargs U-Boot environment variable to specify the LVDS output. For example, you might need to set it to something like video=mxcfb0:dev=ldb,LVDS,if=RGB24. This command can vary depending on the exact specifications of your display and the version of U-Boot you are using.

  4. Configure Qt for the Correct Display: Ensure that your Qt application is configured to use the correct framebuffer device. This is typically /dev/fb0 for the primary display, but you should verify this based on your system’s configuration. You can specify the framebuffer device in your Qt application or through the Qt environment variables (e.g., QT_QPA_FB_DEVICE=/dev/fb0).

  5. Test the Configuration: After making the necessary changes, reboot your system and observe if the display output is now directed to the LVDS display. If the display still does not show the output, double-check the connections and configurations.

  6. Debugging: If the issue persists, you might need to debug further by checking the kernel log messages (dmesg) for any errors related to the display or framebuffer initialization. This can provide clues on what might be going wrong.

Remember, when modifying the device tree or U-

Please, also check if these links can help you solve your problem:

First Steps with Capacitive Touch Display 10.1 Inch LVDS | Toradex Developer Center.


Thank you for contacting us.
Do you have the correct device tree overlays added to your files?
In order for your LVDS screen to work, you will need the correct .dtbo files.
The corresponding developer page for this matter is Device Tree Overlays on Toradex System on Modules.
You will likely need the following components from our git repository:

  • apalis-imx8_lvds_overlay.dtbo: this one “enables” you to use the LVDS
  • display-lt170410_overlay.dtbo: specific display settings for the 10.1" Capacitive LVDS Display from Toradex webshop

Please let me know how you fare with this.

Best regards