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Linux/TUSB8041: TUSB8041 recognition problem

bang songkuk
Prodigy 60 points
Part Number: TUSB8041
Other Parts Discussed in Thread: BEAGLEBOARD-X15, , AM5728

Tool/software: Linux

Dear sir

We are developing the board with reference to the BeagleBoard-X15 board.

However, the TUSB8041 recognition problem faced a difficult situation.

When the power is turned on, the TUSB8041 recognizes the USB 2.0 mouse, and sometimes it does not recognize it.

In this case, measuring the USB VBUS voltage will measure + 0.6V .If it is recognized normally, + 5.0V is measured.

We can not find out what causes this problem.We attach the schematic we designed.

I look forward to your reply.

Best regards,

skbang

2746.SCHEMATIC1 _ p12_AM572x USB POR1.pdf5444.SCHEMATIC1 _ p76_USB HUB.pdfSCHEMATIC1 _ p77_AM5728_USB1.pdf

  • 0
    TI__Expert 7395 points

    Hello Bang,

    I have a few recommendations based on your schematic implementation.

    • Add an external pull-down resistor to the TEST terminal (4.7K is recommended)
    • Check your power-up sequence. When VDD33 is stable before VDD, which is your case, you need to implement an active reset to assert GRSTz low for at least 3 ms after both power supplies have reached their stable levels. Check section 7.6 of the datasheet for additional details.
    • Please also make sure that soldering on the thermal pad is properly done (covering enough area) and evenly distributed.

    Regards,

    Jorge.

  • 0 in reply to Jorge Llamas (SWAT)
    Prodigy 60 points

    Dear Jorge.

    Thank you kindly answer.

    I attached the measured TUSB8041-RESET pin timing file. ( PCB images are also attached.), The ground is well distributed in the PCB inner layer.

    First, VDD3.3V is supplied and VDD1.1V is supplied immediately.

    The TUSB8401-RESET timing is greater than a minimum of 20 ms.

    Could you please review the attached measurement graph?

    The TEST pin is marked as PD in the manual. Do I need to connect a 4.7K resistor separately to the outside ?

    Regards,

    sk,bang

    TUSB8401_RESET.pdf

  • 0 in reply to bang songkuk
    TI__Expert 7395 points

    Hello Bang,

    When the issue occurs, is it only the mouse on the downstream port not being recognized? Or is it the entire TUSB8041 not being recognized?

    USB VBus voltage measurements mentioned on your first post ("USB VBUS voltage will measure + 0.6V") are taken on the upstream or the downstream port where the mouse is connected?

    One additional observation on your schematic, if you are using 5V logic for upstream VBus detection (USB1_DRVVBUS), then you should change R329 to 10K

    Thanks,

    Jorge

  • 0 in reply to Jorge Llamas (SWAT)
    Prodigy 60 points

    Dear Jorge

    In Linux, the TUSB8041 chipset is recognized.

    However, there are some ports on the downstream port that are not recognized. This does not happen every time.

    Since we are connected to the TUSB8041 upstream and the AM5728, we used a 16K resistor.

    Is there anything else we need to review ?

    Thanks,

    sk,bang

  • 0 in reply to bang songkuk
    TI__Expert 7395 points
    Dear Bang,

    On your original post you mentioned that when the failure occurs "measuring the USB VBUS voltage will measure + 0.6V .If it is recognized normally, + 5.0V is measured.", so you are referring to VBUS on the downstream port where device (Mouse) is connected? If that is the case, can you check what is the state of the corresponding PWRONX/BATENx when the issue happens and you have a low voltage level on VBUS?
    What is the state of the corresponding OVERCURx terminal when the issue occurs?

    Regards,
    Jorge