Limit current provided by USB host

  • Hello Support-Team,


    Is it possible to configure the USB host functionality in a way so that only one bus-powered USB device is enumerated which claims a maximum current of 100 mA and rejects USB devices which ask for more current?


    Background: We use a battery driven efusA9X board with WEC2013 and want to limit the current provided by the USB port to avoid that USB devices deplete the battery too fast.

    The device supports the USB classes mass-storage and printer.


    In this context I have noticed that the USB host at our device does not support external hubs (self made kernel). I'm wondering if it is possible to add support of hubs? I have found no appropriate catalog item to do so.


    Best regards,

    Habi

  • Hello,


    >> ... 100 mA and rejects USB devices which ask for more current?

    << Overcurrent detection by the CPU can only be done in the context of USB Specification Revision 2.0. So i asume you Need additional HW.


    >> In this context I have noticed that the USB host at our device does not support external hubs

    << Should work out of the box. Did it help to set: HKLM\Drivers\Builtin\HCD_HSH<your>\PhysicalPageSize=dword:40000 or higher?

    PS: can you test this on a SKIT with Standardkernel and your HUB?

    F&S Elektronik Systeme GmbH
    As this is an international forum, please try to post in English.
    Da dies ein internationales Forum ist, bitten wir darum, Beiträge möglichst in Englisch zu verfassen.