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Author Topic: Interesting, WinUSB show USB speed is different from USBView.  (Read 11367 times)

lanmanck

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Interesting, WinUSB show USB speed is different from USBView.
« on: May 23, 2013, 02:27:01 am »
Hi,Guys.
I just have my devcie working. But there is a interesting I have no idea:
When open it using WinUSB, it show the speed is LOW, code from M$: "WinUSB How to.docx"
When view it using USBView from WindowsDDK from M$, it show the speed is FULL(that 's what I want).
So have you met this problem before? if did, why?
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Jan Axelson

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Re: Interesting, WinUSB show USB speed is different from USBView.
« Reply #1 on: May 24, 2013, 07:54:53 pm »
The Microsoft documentation for WinUsb_QueryDeviceInformation has been wrong. The function returns one of two values for device spped, "low or full" or "high or higher". I don't know how usbview determines speed, but I believe the source code is in the wdk.
« Last Edit: May 27, 2013, 09:16:23 am by Jan Axelson »
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lanmanck

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Re: Interesting, WinUSB show USB speed is different from USBView.
« Reply #2 on: May 24, 2013, 10:37:16 pm »
I also beleive that, using bus hound also return FULL speed. I will try to ask them in Microsoft forum :-)
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Jan Axelson

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Re: Interesting, WinUSB show USB speed is different from USBView.
« Reply #3 on: May 27, 2013, 09:15:10 am »
Here is the corrected documentation:

If InformationType is DEVICE_SPEED, on successful return, Buffer indicates the operating speed of the device. 0x03 indicates high-speed or higher; 0x01 indicates full-speed or lower.

http://msdn.microsoft.com/en-us/library/windows/hardware/ff540290%28v=vs.85%29.aspx
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