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TSC2007: Touch Screen Drivers Interface Y+/Y- cannot work

Kevin Huang8
Genius 3185 points
Part Number: TSC2007

Tool/software:

Hi Team,

After connecting the touch panel, TSC2007 X+/X- has measured the voltage of 3.3V, and there is a voltage change when touching.
But TSC2007 Y+/Y- cannot measure the 3.3V voltage. (After swap panel terminal X+/X- to Y+/Y- pin, still cannot measure the voltage)
Does Register need to be set?

  • 0
    TI__Mastermind 22860 points

    Are you writing any data to registers? How do you read the data?

  • 0 in reply to Sanjay Dixit
    Genius 3185 points

    Hi Sanjay,

    Before issue has been resolved. as now current issue is about the stability of the touch board. Is there any recommended value for the touch board model?

  • 0 in reply to Kevin Huang8
    TI__Mastermind 22860 points

    Can you please explain what you mean by touch panel stability ?

  • 0 in reply to Sanjay Dixit
    TI__Genius 9725 points

    Hi Sanjay,

    the issue is, when the touch pen slide on the touch panel, the touch point sometimes will not follow the touch pen's slide path, instead it will jump to to the left bottom 

    Customer are now using Linux driver and setting as below, 

    tsc2007@48 {

                  compatible = "ti,tsc2007";

                  reg = <0x48>;

                  pinctrl-names = "default";

                  pinctrl-0 = <&ts_default>;

                  interrupt-parent = <&pio>;

                  interrupts = <0 0x8>;

                  gpio = <&pio 0 0>;

                  ti,x-plate-ohms = <650>;

      };

    Can you help review if any suggestion?  thanks!

  • 0 in reply to PYTsai
    TI__Mastermind 22860 points

    Please send me your schematic

  • 0 in reply to Sanjay Dixit
    TI__Genius 9725 points

    Hi Sanjay,

    customer's schematics attached, pls help check !

    trk-06-m_tsc2007.pdf

  • 0 in reply to PYTsai
    TI__Mastermind 22860 points

    Sometimes switching noise can disrupt behaviour of the touchscreen. We normally suggest 1n capacitors on X+,X-/Y+,Y- pins.

    Is there some switching supply in the vicinity? 

  • 0 in reply to Sanjay Dixit
    TI__Genius 9725 points

    Hi Sanjay,

    The X+/X-/Y+/Y- routing short in inner L8 layer and surround by ground plane (adjacent layer are also ground ).

    The X+,X-/Y+,Y- pins. layout out should be fine, is it ? 

    Also customer had tried add 0.01uF on X+,X-/Y+,Y- pins. but problem the same. Should i ask customer try 1nF ? 

    is there any thing else we can check? 

    thanks!

  • 0 in reply to PYTsai
    TI__Mastermind 22860 points

    Is this an intermittent issue or is it always present

  • 0 in reply to Sanjay Dixit
    TI__Genius 9725 points

    Hi Sanjay

    This issue is always present and easy to duplicate.

  • 0 in reply to PYTsai
    TI__Mastermind 22860 points

    I shall reply shortly

  • 0 in reply to Sanjay Dixit
    TI__Mastermind 22860 points

    You can try the below.

    Remove the touchscreen connections. Take a DC Power supply and connect its output through a 470 ohm resistor to X+ pin.

    Take a second DC Supply and connect it with 470 ohm resistor to y+

    Fix the Y+Voltage to 1.65v DC. Then shift X+Voltage from 0v to 3v

    Does the touch panel create a stable  x coordinate from left to right of screen?