Do you have LibUSB installed? You'll need a binary backend in addition to
the Python bindings.
You can follow the installation instructions located at
http://sourceforge.net/apps/trac/libusb-win32/wiki.
On Tue, Nov 29, 2011 at 11:11, Barney, Bryson <bbar...@sandia.gov> wrote:
> Hi,
>
> I am new here, and a new user of PyUSB. I have a very simple HID
> Isochronous application to use this for, so I thought that I would start
> out by running the example that is shown in the “Programming with PyUSB
> 1.0” tutorial. I am running this on windows 7 with python27
>
> I get through the following lines:
>
> import usb.core
> import usb.util
>
> # find our device
> dev = usb.core.find(idVendor=0xfffe, idProduct=0x0001)
>
> Then “ValueError: no backend abailable” appears, which is an error from
> line 846 in core.py. It looks like I have all three backends (libusb01.py,
> libusb10.py, and openusb.py) in the usb/backend directory. Do you by any
> chance know why it cannot find a backend? Any help with this would be much
> appreciated.
>
> Thanks,
> Bryson
>
> Just in case, here is the script that I am trying to run:
>
>
> import usb.core
> import usb.util
>
> # find our device
> dev = usb.core.find(idVendor=0x0B40, idProduct=0x0133)
>
> # was it found?
> if dev is None:
> raise ValueError('Device not found')
>
> # set the active configuration. With no arguments, the first
> # configuration will be the active one
> dev.set_configuration()
>
> # get an endpoint instance
> cfg = dev.get_active_configuration()
> interface_number = cfg[0].bInterfaceNumber
> alternate_settting = usb.control.get_interface(interface_number)
> intf = usb.util.find_descriptor(
> cfg, bInterfaceNumber = interface_number,
> bAlternateSetting = alternate_setting
> )
>
> ep = usb.util.find_descriptor(
> intf,
> # match the first OUT endpoint
> custom_match = \
> lambda e: \
> usb.util.endpoint_direction(e.bEndpointAddress) == \
> usb.util.ENDPOINT_OUT
> )
>
> assert ep is not None
>
> # write the data
> ep.write('test')
>
>
>
>
>
> ------------------------------------------------------------------------------
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>
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All the data continuously generated in your IT infrastructure
contains a definitive record of customers, application performance,
security threats, fraudulent activity, and more. Splunk takes this
data and makes sense of it. IT sense. And common sense.
http://p.sf.net/sfu/splunk-novd2d
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