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TUSB3410 GPIO pin frequency

Rob McCarthy
Prodigy 575 points
Other Parts Discussed in Thread: TUSB3410

Some of the GPIO pins on the TUSB3410 have a frequency on them. They have noticed that the frequency changes or goes to zero after a system ESD event. They would like to monitor one of the pins to tell if an ESD event has occured. Is this some thing that can be relied on? what generates this frequency and why would it change?

 

  • 0
    TI__Genius 16440 points

    Hi Paul,

    The Win 7 driver is now available at our website: http://focus.ti.com/docs/toolsw/folders/print/tusbwinvcp.html

    Thanks and Best Regards,

    Ismael 

    From: PAUL SCHOENKE [mailto:pschoenke@arrow.com]
    Sent: Martes, 10 de Noviembre de 2009 09:44 a.m.
    Subject: RE: 1-634188293 from Americas PIC regarding part number TUSB3410 Arrow

    Thanks again Ismael.  The latest feedback that I received from Thermo Fisher follows:

    Hi Paul,

    Thanks for the additional information.  The SUSPEND pin does not seem to notice the kind of failure that we are seeing, which is why we are monitoring the P3.3 pin for the frequency shift to detect that the link is down.  It would have been nice if the SUSPEND pin would have been able to report this problem.

    We suspect that the problem with the com link is mostly on the PC end, and the P3.3 pin frequency shift is a side effect of the operation of the TUSB3410 while the com link is in that mode.

    We are speculating that resetting the TUSB3410 appears to the PC as though the cable has been plugged out and then in, triggering a re-initialization of the link, which then clears the problem.   It is an ugly work around, but we want to get the product to be robust enough to win the CE sticker.

    We are going to test operation under VISTA and Windows 7, and I understand that new drivers are in the works, which we will check too when they become available.

    Thanks,

    Bob

    From: Ismael Duron [mailto:iduron@ti.com]
    Sent: Tuesday, November 03, 2009 9:46 AM
    Subject: RE: 1-634188293 from Americas PIC regarding part number TUSB3410 Arrow

    Julie, 

    These are some GPIO being used in our default FW source code.

    P3.3 à is being toggled to monitor the usage of watchdog timer…

    P3.4 à is being toggled tell if code is running…

    P3.1 à is only being used in the special case of setting a flag for high power consumption…

    P3.0 à I don’t see that it’s being used… 

    So maybe P3.0 and P3.1 can be customized by the customer.

    About these P3 terminals, according to the spec: 

    • 3-state CMOS output (±12-mA drive/sink).
    • TTL-compatible, hysteresis input, with internal 100uA active pullup resistor.
    • The MCU treats the outputs as open drain types in that the output can be driven low continuously, but a high output is driven for two clock cycles and then the output is high impedance.

    It’s also mentioned “that each GPIO terminal has an associated internal pullup resistor. It is strongly recommended that the pullup resistor remain connected to the terminal to prevent oscillations in the input buffer. The only exception is if an external source always drives the input.” 

    Thanks and Best Regards,

    Ismael

    Julie / Ismael;
    Thanks. I just got this back from Thermo and will await their additional feedback.
    Paul
    ------
     Thanks for the additional information. We were in a tight spot, finding a failure mode on Wednesday two weeks ago, and needing to go to CE testing the following Sunday.  We had to scramble to get something together on short notice.  As it turns out, we will have to retest this part for an unrelated reason, so there is still time for us to get it right.  I’ll ask Eoin to revisit the SUSPEND pin, to see if it does change state or not during the ESD provoked failure mode.
    From: "Nirchi, Julie" <nirchi@ti.com>
    Date: Mon, 2 Nov 2009 14:16:29 -0600
    Subject: RE: 1-634188293 from Americas PIC regarding part number TUSB3410 Arrow

    Hi Paul, 

    The SUSPEND pin would go high and stay high, it shouldn’t just toggle.  I was hoping to use a documented pin function to initiate the reset recovery, but it appears they don’t see anything that tracks the ESD failure.  Obviously, using what appears to be a somewhat predictable failure mode to initiate a reset recovery is not a robust solution.

    Ismael, 

    Do you know if there are functions are assigned to these pins (P3x) in the TI firmware?  Are the internal pullups enabled on the terminals?

    Regards,

    Julie

    From: PAUL SCHOENKE [mailto:pschoenke@arrow.com]
    Subject: RE: 1-634188293 from Americas PIC regarding part number TUSB3410 Arrow

    Thanks Julie.  Feedback from Thermo Fisher is that they investigated the status of the pins and did a "walk around the chip looking for pins that changed from pre-lockup to post-lockup."   

    The only thing they found was this variation in frequency on one of the GPIO pins (actually on three of the four, I think, although they are only using one.)  So they believe that the SUSPEND line did not change.

    I can ask them to re-test it if you think it is likely that it toggles, as it would be easier for them to sense a level on a pin rather than measuring a frequency.

    Paul

    From: Nirchi, Julie [mailto:nirchi@ti.com]
    Sent: Monday, November 02, 2009 10:13 AM
    Subject: RE: 1-634188293 from Americas PIC regarding part number TUSB3410 Arrow

    When the ESD event occurs and the device goes offline, does the TUSB3410 drive the SUSPEND terminal high?