Colibri IMX6, Windows CE7: Disable LCD

Hello,

I am wondering if it is possible to completely (and persistently) disable the LCD unit on a Colibri IMX6 module running Windows CE7.

We have disabled the splash screen by modifying the Config Block, but this is not enough. We need to ensure that the LCD unit is not active, otherwise we risk IO contention and interference with other circuits on our carrier board.

Previously, our design used a Colibri T20 module. For the T20 running Windows CE7, the LCD could be disabled by changing the “BootupStyle” registry key. Is there anything similar for the Colibri IMX6? If not, what are our options?

Kind regards,
Dylan

UPDATE:

Previously on the T20, we used the “BootupStyle” registry key. The default value for this key is 0x00001, which selects LCD. We used value 0x00010, which selects HDMI. This is the recommended approach for disabling the LCD unit on Txx modules as indicated here.

  [HKLM\Software\Nvidia Corporation\NVDDI]
  "BootupStyle"=dword:0x00010

I see that for the IMX6 there is a registry key “Out” that selects the display driver output port. The default value for this key is 0, which selects Parallel LCD on the Colibri. It looks like a value of 5 selects HDMI. Would this have the same effect as the T20 registry key mentioned above?

[HKLM\Drivers\Display\Colibri]
"Out"=dword:5

Hi, I’m the Toradex AI Assistant. The Toradex Support team will follow up with you shortly!

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Hello Dylan,

Thank you for reaching out with your question about disabling the LCD on the Colibri iMX6 module running Windows CE7. While the “BootupStyle” registry key was used for the Colibri T20, the iMX6 may require a different approach.

Here are some steps you can consider:

  1. Registry Settings: Explore the Windows CE registry for any keys related to display settings. You might find options to disable the display driver or prevent the LCD from initializing during boot. This would be similar to the method used on the T20, though the exact key may differ.

  2. Bootloader Configuration: Check the bootloader settings for any options that might allow you to disable the LCD. This could involve modifying environment variables or configuration files within the bootloader.

These methods focus on software configuration and should help you achieve your goal without hardware modifications. If these options do not provide a solution, further investigation into the specific registry and bootloader settings for the Colibri iMX6 might be necessary.

I hope this helps you in disabling the LCD on your module.

Best regards,
Toradex AI Assistant

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

Imx6dl with Iris 2.0, No Lvds display.

I have now attempted the above and it did not work for me. I used an Colibri IMX6 512 MB V1.1B, and the Colibri Evaluation Board Rev 3.2. The registry key was saved and persisted following a reboot, but LCD activity was still present (e.g. on Colibri SODIMM 44).

I see another forum thread that discusses disabling the display driver on the Colibri VF50 running WEC6.

I would like to attempt the procedure described in the above thread; however, the downloadable zip presumably only contains DLLs compatible with the Colibri VF50 module. Is there a page where I can download an equivalent ( “DDI_NOP.DLL”) for the Colibri IMX6 running WEC7 1.8?

Hi @toradexdbd ,

The DDI_NOP.DLL is not specific to any SOC, so it should work also on iMX6. (you need to get the CE7 version in your case)
The problem it might not work for you is probably because the \flashdisk folder where ddi_nop.dll is stored is not yet mounted when the system tries to load the display driver.
We load all drivers in parallel and there is a way to create dependencies between them, but the display driver is not a normal driver and does not follow the same load machanism.
There is a workaround to make sure the \flasdisk is ready before the display driver is loaded. Change this registry entry:
[HKEY_LOCAL_MACHINE\Drivers\BuiltIn\Wait4FlashDisk]
“LoadAsync”=0

Let me know if this helped

This is the OE/DE signal, which is controlled separately from the other LCD lines. You can disable it using the DisableSyncs key.

Apologies for the delayed update.

As @germano.tx explained, the DDI_NOP.DLL approach did not work initially; however, after applying the suggested registry change and rebooting the system, the LCD interface seems to have been disabled. There is no more activity on the pins in question, as confirmed by Logic Analyser and the use of the IMX6 GPIO Tool.

Thank you both for your prompt assistance!