Run LVDS display using Cortex-M4 core

[stefan_wenninge]

Hello all,

I am attempting to run a LVDS display off of the Cortex-M4 core of an i.MX8MQ SOC.

During my research I stumbled upon several posts on NXP forums that reference a demo application called "rear_view_camera" that seems to do exactly that:

Drive a LVDS display module directly from the Cortex-M4 MCU.

https://community.nxp.com/t5/i-MX-Processors/Rear-View-Camera-Demo-in-M4-Core/m-p/998248

https://community.nxp.com/t5/i-MX-Processors/question-about-imx8qm-M4-rear-view-camer-demo/td-p/1005...

https://community.nxp.com/t5/i-MX-Processors/LVDS-Display-in-Cortex-M4-Core-IMX8QM-is-not-working/m-...

I have however not yet been able to locate the source code (source/vendor/nxp/mcu-sdk-auto/SDK_MEK-MIMX8QM/boards/mekmimx8qm/demo_apps/rear_view_camera) of this demo application or any conclusive documentation that confirms this use case.

Therefore my question: Is it at all possible to run a LVDS display directly with the Cortex-M4?

If so, I would greatly appreciate some pointers as to where to find example code snippets or documentation.

Thank you very much and best regards

Stefan Wenninger

[AldoG]

Hello,

Yes it is possible using the i.MX8QM, but please note that the demo you have seen is delivered with Android Auto BSP, so if you plan on use it you may try with that.

Android Automotive BSP

As for normal SDK you may try with dpu driver examples located at <SDK installation path>\boards\mekmimx8qm\driver_examples\dpu

All documentation is available inside the SDK package at <SDK installation path>\docs

You may download the SDK from here:
https://mcuxpresso.nxp.com/en/welcome

Best regards,
Aldo.

[stefan_wenninge]

Hi,

thank you for your reply and the information you provide within.

Unfortunately I am stuck with the i.MX8MQ SoC in my project.

The i.MX8MQ has a different internal structure compared to the i.MX8QM SoC which prevents the rear_view_camera demo from being used on a plug and play basis.

There are also no similar demos that show how to use any of the display interface with the Cortex-M4 on i.MX8MQ.

Porting this demo to the i.MX8MQ would require a detailed investigation into:
* What internal components of the display controller the i.MX8QM uses for the demo.
* If those components also exist in the i.MX8MQ's display controller.
* If those components have drivers in the i.MX8MQ SDK that can be used.
* If a driver can be implemented by hand for components that do not have a driver.

(Docs to compare: IMX8QMRM section 15.7 and IMX8MDQLQRM section 15)

Unfortunately again this amount of work exceeds the time frame available for this project, which forces me to interface with the display in the standard Linux way.

Best regards
Stefan

[AldoG]

Hi,

Sorry for the confusion at first I thought you were using the i.MX8QM, as for your comments you are right unfortunately porting this example would take such efforts, so using the display with Cortex-A (Linux) would be better.

Best regards,
Aldo.