Hello everybody,

this is my first post to this list, so let me apologize this question:
Am I blind or is there really no search-this-list (apart from using google)? 
I'm pretty sure that I'll gain from other user's contributions, if I could only 
search for them reasonably.

And now for something completely different:
I want to use pyusb together with Win-XP, Python 2.7, libusb 1.2.6.0 and a 
piece of hardware like the one described under 
http://www.harbaum.org/till/i2c_tiny_usb/index.shtml
Is this setup reasonable?

I started with the example under "Let's get it started" on 
https://github.com/walac/pyusb/blob/master/docs/tutorial.rst

libusb named its .dll-file libusb0.dll — despite its version 1.x. Therefore, 
during call of usb.core.find, when pyusb looks for the backend, the backend 
will be found by usb.backend.libusb01. Therefore, I guess, pyusb treats the 
usblib 1.x like an 0.x version.

Should I worry about that?

The example program travels on until line
"alternate_setting = usb.control.get_interface…"
and then it stops with
"USBError: [Errno None] libusb0-dll:err [control_msg] sending control message 
failed, win error: Die Anforderung wird nicht unterstützt." (I think the latter 
sentence translates to "The request is not supported", full error message 
follows at the bottom.)

Is this a problem regarding libusb (as it naïvely sounds like)?
May it due to libusb 1.x be treated like an 0.x version?
May it due to limited communication capabilities of the hardware?

Thanks for any suggestions – Peter



Full error output:

ERROR, UNEXPECTED EXCEPTION
[Errno None] libusb0-dll:err [control_msg] sending control message failed, win 
error: Die Anforderung wird nicht unterstützt.

Traceback (most recent call last):
  File "O:\I²C\USB-I²C mit ATtiny45\SW, Treiber für Python\test.py", line 104, 
in <module>
    main()
  File "O:\I²C\USB-I²C mit ATtiny45\SW, Treiber für Python\test.py", line 68, 
in main
    alternate_setting = usb.control.get_interface(dev, interface_number)
  File "C:\Programme\Python27\lib\site-packages\usb\control.py", line 242, in 
get_interface
    data_or_wLength = 1
  File "C:\Programme\Python27\lib\site-packages\usb\core.py", line 695, in 
ctrl_transfer
    self.__get_timeout(timeout)
  File "C:\Programme\Python27\lib\site-packages\usb\backend\libusb01.py", line 
536, in ctrl_transfer
    timeout
  File "C:\Programme\Python27\lib\site-packages\usb\backend\libusb01.py", line 
384, in _check
    raise USBError(errmsg, ret)
USBError: [Errno None] libusb0-dll:err [control_msg] sending control message 
failed, win error: Die Anforderung wird nicht unterstützt.





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