Re: [pyusb-users] ValueError: No backend available

[Wander L. C. <wan...@gm...>]

2014-05-09 17:53 GMT-03:00 Bruce Lewis <bru...@gm...>:
> Good morning ..
>
> I have an iMac 7.1 running OS X Mavericks and use Enthought Canopy to run
> Python.
> I want to use Python to read data from and write data to USB ports.
> I have used MacPorts to install PyUSB and libusb using their portfiles.
> From Idle I have run...
>
> import usb.core
> import usb.util
> dev = usb.core.find(find_all=True)
>
> and receive the following error...
>
> Traceback (most recent call last):
>   File "<pyshell#5>", line 1, in <module>
>     dev = usb.core.find(find_all=True)
>   File "/Library/Python/2.7/site-packages/usb/core.py", line 867, in find
>     raise ValueError('No backend available')
> ValueError: No backend available
>
> I have trawled through the various web sites that identify this error and I
> have been unable to resolve the problem.
> Does anyone please have a solution?
>

Where is libusb installed at?

-- 
Best Regards,
Wander Lairson Costa