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TSC2007: Touch panel after some time will be no response, recovery after restart.

Leo He
Intellectual 420 points
Part Number: TSC2007

The customer connected the frequency converter through RS485 with our board, and connected the PLC through RS232.

After use for a period of time (the time is not fixed), Touch panel has no response , need to restart the device.

our software test the  IIC signal.      Data transmission is normal, but   the return data is 0 (it feels like that the chip is not working or the host is not answering).

what caused  this problem,? how to solve it?

TP_3V3   and VCC_3V3 are same sourcing. 3V3 is from DCDC convert.

  • 0
    TI__Guru 63995 points
    Hello Leo,

    This is not expected operation of the TSC2007. Can you confirm how you're resetting the device to return to normal operation? Are you toggling the 3.3V power on/off? Are the results of all of the conversion channels (X/Y/Z) zero, or only one measurement?

    Reviewing the schematic we noticed there doesn't appear to be any power-supply decoupling on the VDD (pin1) pin. Can you confirm if this capacitor is located on a a different part of the schematic?
  • 0 in reply to Collin Wells
    Intellectual 420 points
    Hi Collin,
    Yes,the results of all of the conversion channels (X/Y/Z) are zero.

    and We have power-supply decoupling on the VDD (pin1) pin ,it is seem 100nF

    This will not happen if our product is not connected to other devices.
  • 0 in reply to Leo He
    TI__Guru 63995 points
    Hi Leo,

    Thank you for confirming the decoupling capacitance. Do you have to cycle / reset power to the TSC2007 to return it to normal operation? When it becomes non-responsive does it still provide the "ACK" signal before outputting all zeros?

    Is it possible this has to do with SCL clock stretching?
    e2e.ti.com/.../758520