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Original question:

TSC2007: PENREQ output oscillates

TSC2007: PENIRQ output oscillation No.2

Daisuke Higa
Genius 4350 points
Part Number: TSC2007

Tool/software:

Hi support team all.

I've tried following the advice I received in the post below, but it didn't improve, so I'm posting again in a new thread.

 TSC2007: PENREQ output oscillates 

I've recently discovered that when sending I2C commands, the X+ and Y- lines vibrate in sync with the communication cycle.

Has this ever happened before?
I'm sending four commands in the order below, and it appears to respond to commands No.1 and No.4.

I'd really appreciate any help you can give me.

Best regards,

DH

PENIRQ Oscillation.pdf

  • 0
    TI__Mastermind 27320 points

    Hi,

    Thank you for the question, i will update thread by the end of the week

  • 0 in reply to Daveon Douglas
    TI__Mastermind 27320 points

     PENIRQ line toggling in sync with I2C which suggests that the X+ and Y– drivers are actively switching. This can happen if the panel is disconnected or floating, which might lead to toggling due to lack of steady touch input or improper grounding.

    Could you confirm:
    • Whether the touch panel is connected during this test?
    • If there are any external pull-ups or loads on X+/Y– lines?

    Also, PENIRQ behavior depends on the logic level at PENIRQ and internal pull-downs, which vary based on panel resistance and noise. You might be able to try adding a small RC filter externally or modifying the sequence to validate behavior with and without the touch panel connected.