LVDS Problem on Apalis T30 with NEC LCD under WEC2013

Hello support!
I have a problem with your product: Apalis T30 board while trying to connect and use it via LVDS with LCD made by NEC model NL10276BC20-18D

I am using Ixora carrier board. NEC LCD is connected to Ixora with Apalist T30 installed via LVDS wires. All connections triple checked to confirm proper pin setup.
Apalis T30 runs WEC2013. I opened regedit and added under HKLM/SOFTWARE/NVIDIA Corporation/NVDDI new key: LCD.
Under new key LCD I added the following DWORD values: LvdsEnable=0x1, LvdsMap=0x0, LvdsMode=0x1, LvdsRS=0x1, LvdsBitMode=0x1 (see attached picture).
[upload|615rUM609QlMj0LJwlk+L/m6qC0=]

Despite this is done I have no LVDS working. I have LCD with vertical color lines only. I tried multiple different settings, changing resolution, changing key values for lvds and still no results.

[upload|HC7GZuH+AShIVfY/Zj0HbVkSnl8=]

In this picture I use different board but with Ixora results are identical.

Please help me. What can be wrong ?
Is there any way to set LVDS interface in bootloader before board loads Windows CE8 ?
In my case I am changing registry values in Windows but I want LVDS interface to work first of all initially after board boot and then of course in Windows CE8 as well.

What can be wrong with my settings ? For example under HKLM/SOFTWARE/NVIDIA Corporation/NVDDI I did not have LCD key originally so I had to add it manually. After that I had to add DWORD values under LCD key. Is that correct or I was suppose to add Lvds DWORD values directly under NVDDI ?

My LCD is NEC NL10276BC20. Resolution is 1024x768. Display using single channel LVDS with 24bit colors. I use normal scan mode. My suspect is that I do not have LVDS CLK (clock) signal properly from Apalis T30. Oscilloscope shows ~5MHz on Ixora when checking. I would expect it to be at least 50MHz or higher so this is something what may be wrong.
Otherwise something wrong with settings.

  1. What can be wrong in my case ?
  2. How to set LVDS from boot (in bootloader) ?

Please help me. Thanks.

Dear @vinzer

The display driver in the bootloader is completely independent from the one in WinCe. There are also two different ways to configure the display settings. There are three different problem sections, which we need to address individually:

  1. Display Settings in WinCe
  2. Display Settings in the bootloader
  3. Some displays are sensitive to the discontinuity which happens when switching from the bootloader display settings to the WinCe display settings (even if the settings are identical).

Display Settings in WinCe

Let’s start with this part, because you already did the most work for this section. Your approach to create the registry key and adding DWORD values was absolutely correct. I strongly recommend you store these settings in a .reg file (export in Regedit) so you can easily reuse them later. You can also edit the .reg file in a text editor instead of using Regedit.
I guess you also figured out that you need to save the registry in order to keep the settings through a system reboot.

Beside setting the LVDS configuration, you also need to configure the resolution and display timings, as described in the developer page article about display driver registry settings. The timings can be found in the display datasheet.
You are correct, the pixel clock should be in the range of 50MHz. This is configured with the pclk parameter.

Display Settings in the Bootloader

This part is a bit more difficult than the settings in WinCE.

Transition Bootloader (SplashScreen) to WinCe

As mentioned initially, some displays have problems with the switch from splashscreen to WinCe display. Even though the display signals are correct, some displays can’t manage to re-synchronize. To avoid such troubles you can try to disable the splashscreen completely by setting ss.enable=0 in the bootloader configblock.

If you end up in the situation to have a WinCe picture only if the splashscreen is disabled, please get back to me.

Regards, Andy

Dear @vinzer,

I would like to share one working case LVDS configuration registry and boot config block splash screens with you. Please download it from here :

The above settings are done for this display : https://www.toradex.com/capacitive-touch-display-10.1-inch-lvds

Could you adjust the settings for your display in the registry and import it using RegEdit tool then let us know the result.

If you want to apply it from the boot then set splash screen config block.

If you set UseSplashSettings to 1 then display driver from WinCE won’t reconfigure again and would help to avoid the glitches while WinCE GWES launching.

If it doesn’t help, could you dump the registry and splash screen settings and share it with us? Let us verify the parameters for your display.