I need to send data via USB using Python, I'm using PyUSB (http://sourceforge.net/apps/trac/pyusb/) I look for any USB port available, and I tried to send a message:
devList = usb.core.find(find_all=True)
for dev in devList:
for cfg in dev:
for intf in cfg:
sys.stdout.write('\t' + str(intf.bInterfaceNumber) + ',' + str(intf.bAlternateSetting) + '\n')
for ep in intf:
sys.stdout.write('\t\t' + str(ep.bEndpointAddress) + '\n')
if ep.bEndpointAddress:
try:
dev.write(ep.bEndpointAddress, 'test', intf.bInterfaceNumber)
except Exception:
print "\t\terror : dev.write("+str(ep.bEndpointAddress)+", 'test', "+str(intf.bInterfaceNumber)+")"
The result is :
0,0
129
error : dev.write(129, 'test', 0)
0,1
129
error : dev.write(129, 'test', 0)
0,0
136
error : dev.write(136, 'test', 0)
10
error : dev.write(10, 'test', 0)
1,0
139
error : dev.write(139, 'test', 1)
13
error : dev.write(13, 'test', 1)
without try catch it gives:
usb.core.USBError: [Errno None] usb_claim_interface: could not claim interface 0, invalid configuration 0
What is wrong? Is there a best way to communicate via usb with python? because I just have found this lib
As stated in the tutorial:
[...] a device does not work without setting a configuration, even if it has just one! [...]
Apparently most of the times there is only one configuration. Assuming all those configurations are from different devices, you can do something like:
for dev in devList:
for cfg in dev:
cfg.set()
for intf in cfg:
If you can't set a configuration due to "resource busy", you'll need to unload its interface kernel driver:
dev.detatch_kernel_driver(interface)