Merge pull request #155 from openxc/64-bit-python-fix

64 bit python fix

README.rst

@@ -30,6 +30,8 @@ In addition to a port of the Android library API, the package also contains a
 number of command-line tools for connecting to the CAN translator and
 manipulating previously recorded vehicle data.
 
+If you are getting the error "ValueError: No backend available" on windows please reinstall your libusb0 driver using https://github.com/openxc/vi-windows-driver if you are in a envirment where you can not use an unsigned driver  please use https://zadig.akeo.ie/
+
 Due to changes in signals.cpp openxc-python Version 2.0.0 must be used with vi-firmware 8.0.0 or greater. 
 Due to changes with large diagnostic responses Version 2.1.0 must be used with vi-firmware 8.1.0 or greater.
 

openxc/sources/usb.py

@@ -1,9 +1,10 @@
 """A USB vehicle interface data source."""
 
-
+import os
 import logging
 import usb.core
 import usb.util
+from usb.backend import libusb0
 
 from .base import BytestreamDataSource, DataSourceError
 
@@ -58,8 +59,14 @@ def __init__(self, vendor_id=None, product_id=None, **kwargs):
             product_id = int(product_id, 0)
         self.product_id = product_id or self.DEFAULT_PRODUCT_ID
 
-        devices = usb.core.find(find_all=True, idVendor=self.vendor_id,
+        if os.name == 'nt':
+            be = libusb0.get_backend()
+            devices = usb.core.find(backend=be, find_all=True, idVendor=self.vendor_id,
+                idProduct=self.product_id)
+        else:
+            devices = usb.core.find(find_all=True, idVendor=self.vendor_id,
                 idProduct=self.product_id)
+
         for device in devices:
             self.device = device
             try: