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TUSB8040A1 port0 not working in full power management

touzeau patrick
Prodigy 40 points
Other Parts Discussed in Thread: TUSB8040A1

Hello

We have design USB3 hub with TUSB8040A1.

We currently meet a major problem during the pre-serie production.

Port 0 (and always port0) detect an over-current in full power management mode.

The OVERCUR0Z pin force the level 0 even with or without a 4.7k ohms pull up. This OVERCUR0Z is normaly an input !!!

When we disable the full power management mode by removing the 4.7k pull down on FULLPWRMGMTZ pin then the over-current never occured.


Is anybody meet this problem ?  Any solution ?


Thanks in advanced for your help

  • 0
    TI__Guru* 76130 points
    Hello,
    Please provide your schematic, you can email them to elias.villegas@ti.com
    Regards
  • 0 in reply to Elias Villegas M.
    TI__Guru* 76130 points
    Hello,

    "We will need to see the part of the schematic that generates ILM_SEL_0_1, the OVERCUR0Z should never be an output unless the device is held in a test mode.

    Also, some general feedback:
    The TUSB8040A1 is not rated as a bus-powered hub Installing a pullup on SS_SUSPEND turns off SSC, which is functional but not USB compliant.
    If they are using a SMBUS host, can they send the configuration settings for the TUSB8040A1?"
  • 0 in reply to Elias Villegas M.
    Prodigy 40 points

    Hello


    On the board the pull up on SS_SUSPEND is not populated.

    Regarding the schematic, the signal ILM_SEL_0_1 is generated by a microcontroler. I remove the microntroler from the board : in that case  the IO OVERCUR0Z is only connected to the pull up. The result is the same : the I/O OVERCUR0Z is force to 0 in the full power management mode.


    What are the conditions to force the TUSB8040A1 in test mode ?

    Regards

  • 0 in reply to touzeau patrick
    TI__Guru 60870 points
    Does the hub report an overcurrent condition to the host or turn off downstream port power? If either of those events occur, then the hub is not in test mode. Test mode is entered using the JTAG interface which appears to be properly disabled in this application. When fullpwrmgmtz is high, does OVERCUr0z still go high? Do you see this problem on multiple platforms?
  • 0 in reply to JMMN
    Prodigy 40 points

    Hi

    The port OVERCURZ0 is connected to an external 4.7k pull up and not connected to any other device.

    After de-assertion of reset the OVERCURZ0 port is forced to 0 by the TUSB8040A1 HUB  (in that case fullpwrmgmtz the force to 0 by an external 4.7k pull down) and then signaling an over current to the PC and  turning off downstream port power.

    When fullpwrmgmtz is high (1 = Full Power management not supported, internal pull up and no external pull down), the OVERCUr0z stay high.

    Yes I see the problem on multiple platforms. Around 30% of my board has the defect. The other boards are working normaly.


    Regards

  • 0 in reply to touzeau patrick
    TI__Guru 60870 points

    Can you ohm out the OVERCURZ0 on passing and failing platforms and see if they are similar?  Does the OVERCUR0z go high before upstream port is connected or afterwards?  Does it go low after the upstream port is disconnected? Can you force the TUSB8040A1 into programming mode and see if the OVERCUR0z is still high?  You can do this by pulling DP and DM on one of the downstream ports to 3.3V for 1-2 seconds.


    Thanks,

    JMMN

  • 0 in reply to JMMN
    Prodigy 40 points

    Hi
    is it possible to organize a conference call and discuss about the problem.

    In complement the impedance on Port0 when they are not working is about 2.3k with a 4.7k pull up and 4.3k when it is working with also a 4.7k pull up.

    In ganged mode I don't have the over current event.

    The over current event occured always independtly if an upsteam is connected or not...

    Waiting for a call

    Regards

  • 0 in reply to touzeau patrick
    TI__Guru 60870 points
    Arranging via direct email.