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TUSB2046BVF without EEPROM?

Frank Tran
Prodigy 40 points
Other Parts Discussed in Thread: TPS2041, TUSB2046B

Hi TI,

I design a USB Hub Controller, and I follow  bus power hub on TI web design reference.  The computer recognizes the up steam port, and displays Generic USB Hub in Device Manager.  However, when  I try to connector to different USB devices (FT232R USB UART IC,  USB mouse, USB hard disk, and so on) in down stream ports,  my computer does not see these devices.  Do I miss something in my design?

 

Thanks

Frank,

Note: I use two USB down stream ports and leave the other two floating.

  • 0
    Prodigy 40 points

    Dear IT,

    Also, I have 5-volt to down stream ports using TPS2041 (I measured: PWRON1-4 are low, and OVRCUR1-4 are high). SUSPND is low at all time.

    Thanks,

    Frank,

  • 0 in reply to Frank Tran
    TI__Guru* 76130 points

    Hello Frank,

     

    It is probably a power up timing issue. There are critical timing parameters that have to be met for the reset signal at power up, also, if the downstream devices complete its power up sequence before the hub does, they probably will enter into suspend mode causing the host do not "see" them.

     

    We need your schematics in order to give more valuable help.

    Are the downstream devices self-powered?

     

    Regards.

     

  • 0 in reply to Elias Villegas M.
    Prodigy 40 points

    Dear  Elias,

    I have my schematic in attachment.  My downstream devices are bus-powered hub.  Also, my design has less bypassed capacitors comparing to other designs of TUSB2046B on this forum.

    Many thanks for your help

    Frank,

     

     

    TUSB2046B.pdf
  • 0 in reply to Frank Tran
    TI__Guru* 76130 points

    Hi Frank,

     

    There are some issues with your schematic:

    Recommendation:

    1) Place a 2.2K series resistor between XTAL2 and C12 (22pF)  cap.

     

    Must to have:

    1) The reset circuit DS1233AZ provides a 350ms long reset pulse, this condition violates the USB 2.0 specification since a USB device must be able to respond to the host within 100ms after power up.

    You can use an RC circuit to reset the TUSB2046;  using a 2K resistor with a 0.1uF:         3.3V------------2.2K----------------------~RESET(TUSB2046)

                                                                                                                                                                                                                |

                                                                                                                                                                                                              0.1uF

                                                                                                                                                                                                                |

                                                                                                                                                                                                              Gnd

    2) You must place a pull-up resistor(15K) on the OVRCUR terminals.

    3) You must  terminate the unused downstream ports with a 15K pull-down.

     

    Regards.

  • 0 in reply to Elias Villegas M.
    TI__Guru* 76130 points

    Frank,

     

    Can you please make the above changes to your design, hopefully they're gonna fix the problem.

     

    Regards.

  • 0 in reply to Elias Villegas M.
    Prodigy 40 points

    Dear Elias,

    I followed your instruction step by step, and it works like a charm.  I am grateful for your help, and I wish you are always succesful in your career, so that all the TI users will be successful too.

    Best Regards,

    Frank,