PORTS Forum

Ports and Interfaces => USB => Topic started by: lanmanck on May 23, 2013, 02:27:01 am

Title: Interesting, WinUSB show USB speed is different from USBView.
Post by: lanmanck 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?

Title: Re: Interesting, WinUSB show USB speed is different from USBView.
Post by: Jan Axelson 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.

Title: Re: Interesting, WinUSB show USB speed is different from USBView.
Post by: lanmanck 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 :-)

Title: Re: Interesting, WinUSB show USB speed is different from USBView.
Post by: Jan Axelson 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