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USB enumeration RRS feed

  • Question

  • Hello,

    when I capture an enumeration proccess of an USB device in Win 7 and Win 8 I can see it goes through these steps (they totally take few miliseconds):

    1) HOST: Get descriptor from Device (Device descriptor)

    2) DEVICE: Replies with Device descriptor

    3) HOST: Get descriptor from device (Configuration descriptor)

    4) DEVICE: Replies with Configuration descriptor: 0x09 0x02 0x29 0x00 0x01 0x01 0x00 0x00 0xFA

    5) HOST: Get descriptor from device (Configuration descriptor)

    6) DEVICE: Replies with Configuration descriptor: 0x09 0x02 0x29 0x00 0x01 0x01 0x00 0x00 0xFA

    My question is: Why steps 3,4 and 5,6 (get configuration descriptor) repeats?

    I developed an USB HID device which, under certain conditions, fails enumeration at step 6 (I get a transaction error on this step) and I get code 10 error in Windows for this device.


    Sunday, September 21, 2014 2:05 PM