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TUSB2077 HUB communication with Mobile Devices

Adair Rodriguez
Prodigy 130 points
Other Parts Discussed in Thread: TUSB2077A

I designed a 5-port USB HUB for connecting to a mobile phone.

On my first test, I connected it to a PC so i can be sure it works. The thing is, sometimes it disconnects from the PC, or doesn't recognizes some USB memories (2.0)


But it kind of works. and the HUBCFG pin stays High


But if i connected to a mobile phone, my phone doesn't recognizes the Hub, and of course, the HUBCFG pin stays OFF. I tried with a Hub I buoght from a store, and my mobile phone does recognizes the HUB and whatever device i attach to it.

Can you help me, please?

THANK YOU

  • 0
    TI__Mastermind 18655 points

    Hello Adair, 

    Are you following the requirement for the reset signal timing?

    The TUSB2077A requires a power on reset pulse of between 100us to 3ms after 3.3-V (Vcc) reaches its 90%. . Anything less than 100 us is too short for the device and anything longer than 3ms can interfere with USB enumeration.

    Please, take a look at this document, it  can clarify some doubts you may have regarding our product.

     

     

    Could share your schematics? I can review them and provide feedback.

    Regards, 

  • 0 in reply to Joel Jimenez0
    Prodigy 130 points

    Good day,

    Thank you for the replay.

    The thing is, I need the USB HUB to work as a Stand-Alone Device, without any microprocessor control.

    So, for this porpouse, does it going to work?

    THANK YOU

  • 0 in reply to Adair Rodriguez
    TI__Mastermind 18655 points
    Adair,
    No, an USB HUB is fully under the control of an USB host system, therefore, an USB Host is required.
    Regards.
  • 0 in reply to Joel Jimenez0
    Prodigy 130 points
    Sorry, I think I didn't made myself clear. When I talked about a microprocessor, I meant it to send the reset signal.

    The USB HUB is going to be controlled by an Android Tablet, I mean, the Tablet is going to be it's host. but it'll only be attached using the USB.
    So there's no way it can send a Reset Signal (this is why I talked about it to work as a Standalone device, without a processor that send the Reset signal)

    I have USB HUBs I bought on stores like Office Depot, and they don't have a microcontroller inside.

    I'll wait for your comments

    THANK YOU
  • 0 in reply to Adair Rodriguez
    TI__Mastermind 18655 points

    Adair, 

    We use an external RC circuit in our evaluation board( 15K pull-up resistor and .1 uF cap). This circuit will held the  reset  low for somewhere within the range.

    Regards,
    Joel