Enabling touch on 10.1" Display LVDS - Touch pins are integrated into LVDS interface

Technical Support
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1

Hi there,

I am using Apalis iMX8 on Ixora Carrier Board V1.2A.

I was using Capacitive Touch Display 10.1" LVDS from Toradex and its part number is LT170410-2WHC.
Now, I have an almost identical display from the same supplier and the part number is LT170410-1WHC (link to the datasheet: https://www.endrich.com/sixcms/media.php/2/10.1%20LT170410-1WHC%20Rev%201.pdf). The only difference is that the LT170410-1WHC does not have an FFC cable for the capacitive touch but instead, the touch pins are integrated to the LVDS interface. So, I am looking for a correct approach to enable the touch feature with the LVDS interface on this display. So, I am assuming a different overlay file would be necessary.

so this is the LVDS interface of the display and only the ones in yellow are different than the Toradex Display.

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Note: I understand the assembly of the pins in the LVDS connector is important, this would be the next step.

Thank you in advance
Samir

3

According to your display’s datasheet, it utilizes the same touch sensor IC (Atmel Mxt1066T2), so you only need to create a simple passive adapter to split signals from the display into two cables. One cable will connect the touch interface to the X24 connector on the Ixora board, while the LVDS, PWM, BL, and power will be connected to the X19 connector on the Ixora board.

If you opt to populate the unassembled Ixora resistors R177, R178, R179, and R180 with 0 Ohm values, and remove R127 and R128, you can exclusively utilize the Ixora X19 connector for your display. The only remaining step would be to fabricate the appropriate cable. For more detailed information, please refer to the Ixora schematics

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If you have any further inquiries or require additional assistance, feel free to ask. Best of luck with your project!

4

Hi Alex,

Thank you very much for your response, this clarifies a lot.

As the next step, I am fabricating the required cable that is aligned with your second approach. I am trying to populate the unassembled Ixora resistors R177, R178, R179, and R180 with 0 Ohms. I couldn’t find where are these pads on the Ixora board. Can you help me locate them?

Thank you,
Samir

5

Click on the PCB tab here - Ixora Carrier Board | Toradex Developer Center

6

Thank you very much. This is very helpful. I will update this thread with my findings.

Best,
Samir

7

Hi Alex,

I have manufactured the custom-made cable and made all the modifications as per your recommendation.

I don’t have the touch feature now.

As I can see now, As R97 and R100 are 0Ohms and connected to the same 3.3V source, now, GPIO5 and GPIO6 pins are shorted (connected to the 3.3V without any resistance). It seems to me that the R97 and R100 resistors should be either removed or I need to add pull-down resistors at the R99 and R102. Can you please let me know about it?

Thank you and best regards,
Samir

8

Hi,

In addition to Alex’s proposed solution, removing the R97 and R100 solved the issue.

Overall, the approach to use exclusively the Ixora X19 connector for the display these steps need to be taken on the Ixora board:

  • Removing R97, R100, R127, and R128
  • Populating R177, R178, R179, and R180 with 0 Ohm values

Thank you, Alex.

Best regards,
Samir