Re: [pyusb-users] No backend available with windows 7

[Xiaofan C. <xia...@gm...>]

On Tue, Mar 3, 2015 at 2:40 AM, Michel Allaire <mic...@vi...> wrote:
> But it seems that I can't access the list devices on the bus with the
> following script:
>
> import usb.core
> import usb.util
>
> list_dev = usb.core.find(find_all=True)
> n = 0
> for dev in list_dev:
>     n = n+1
>     print (n, "  " , dev)
>
>
> Could it be because I did not specified any filter or .INF file since I want
> to scan the bus myself to connect to microcontrollers in a arbitrary number
> and USB ready

Yes. If you use libusb-win32 under Windows, you have to have
one supported device with libusb0.sys driver.

If you use libusb-1.0 backend (libusb Windows backend), then you
do not need to have a device with a supported driver (eg WinUSB) to find
the device, but then you need to have such a device if you want to do
more than that (read/write endpoint, etc).

> Will this behavior also exists on my target operating system with will be
> Linux running on à Raspberry PI.

No. Linux is different since libusb uses usbfs under Linux (you do need
to detach non-usbfs driver first).



-- 
Xiaofan