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Thread: Windows USB example

  1. #41
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    Default Re: Windows USB example

    Hi All,
    After I found this example I was very happy and even before trying I modified it to match with my application... then I found out that device detection worked properly but write failed.
    I get a proper read and write handle, no errors at write, but... it seems to send nothing.

    I went back to the example changed nothing but MY_DEVICE_VIDPID and added a debug message after WriteFile to check BytesWritten
    It may be clear that the protocol to my device differs, but I should at least be able to send something even when it is wrong -- or not?
    If I only received an error would help already

    any ideas?
    Thanks

    ---
    BytesWritten always 0
    Last edited by Marc van der Kamp; 14th March 2012 at 08:37.

  2. #42
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    Default Re: Windows USB example

    Oops... inverted my error checking, WriteFile did give an error (87)

  3. #43
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    Default Re: Windows USB example

    Hi there,
    I have the same error..I am wondering if you managed to fix it!!
    Thanks

  4. #44
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    Default Re: Windows USB example

    Quote Originally Posted by gavagai View Post
    Don't use the class GUID returned by device manager, it don't works. It is the device SETUP GUID class. We need the device INTERFACE GUID class (see http://msdn.microsoft.com/en-us/libr...(v=vs.85).aspx).
    Try this:
    - be sure that your device is installed and recognized in the system
    - start regedit and search for your vid&pid (VID_XXXX&PID_XXXX) in the following key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Contro l\DeviceClasses. You can get more of a result.
    - Try to use the parent class GUID where the descriptor starts with the type of device (##?#HID#VID... or ##?#IMAGE#VID...).
    For more informations see the examples in http://msdn.microsoft.com/en-us/library/ff551069.aspx

    Your device seems to be an image device. I do not know if endpoint size (InputBuffer and OutputBuffer size) is correct for this device. Depends on the driver.

    Good luck
    Hi gavagai,
    First of all thanks for the great upload.
    I am tryint to build qt application to detect a usb device(Not necessarily a HID) when plugged in.
    Now, i have two HIDs connected to my PC a keyboard and a mouse.
    how do i know which VID/PID is for which device? Coz its really confusing even when i navigate to registry location you mentioned above.
    how does HID differs from Mass storage device in terms of VID/PID?
    Just want to put me in the right direction.
    Thnx.

  5. #45
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    Mar 2012
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    Default Re: Windows USB example

    Hi Marc van der Kamp,

    I am still getting error 87.. Have you fixed it ? I really need to make it work..
    Please help me..

    Many thanks

    Quote Originally Posted by Marc van der Kamp View Post
    Oops... inverted my error checking, WriteFile did give an error (87)
    Hi Marc van der Kamp,

    I am still getting error 87.. Have you fixed it ? I really need to make it work..
    Please help me..

    Many thanks

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