我有：USB HID原始温度/湿度传感器覆盆子Pi B.
我想：python从PI上的USB传感器获取数据
借助几个不同的网页和本网站上的一些答案，我找到了设备，我可以显示界面细节并发送一个数组并获得一个数据点，但随后设备忙碌而且超时 . 为什么它只发送一个读数然后需要重新插入以获得另一个数据点？我的第一个想法可能是它是设备，但设备在我的窗户盒上工作得很好 . 我的python代码错了吗？ USB设备在中断IN endpoints ＃1上发送16位数据，并在中断OUT endpoints 2上接收数据（因为这是我编写固件的方式） .
Python代码：
#!/usr/bin/env python
import usb
import sys
dev = usb.core.find(idVendor=0x1dfd, idProduct=0x0006)
if not dev:
raise IOError('Device not found')
else:
# dev.set_configuration()
cfg = dev.get_active_configuration();
# cfg = [(0,0)]
print ("Device located")
print ('configuration ' + str(cfg));
for configuration in dev:
for interface in configuration:
ifnum = interface.bInterfaceNumber
if not dev.is_kernel_driver_active(ifnum):
continue
try:
print "detach %s: %s" % (dev, ifnum)
dev.detach_kernel_driver(ifnum)
reattach = True
renum = ifnum
except usb.core.USBError, e:
pass
dev.set_configuration()
interface_number = 0
alternate_setting = usb.control.get_interface(dev,interface_number)
intf = usb.util.find_descriptor(cfg, bInterfaceNumber = interface_number,bAlternateSetting = alternate_setting)
epO = usb.util.find_descriptor(
intf,
custom_match = \
lambda f: \
usb.util.endpoint_direction(f.bEndpointAddress) == \
usb.util.ENDPOINT_OUT
)
epI = usb.util.find_descriptor(
intf,
custom_match = \
lambda f: \
usb.util.endpoint_direction(f.bEndpointAddress) == \
usb.util.ENDPOINT_IN
)
# write the data
print('epI length ' + str(epI.bLength))
print('ep desc type ' + str(epI.bDescriptorType))
print('ep address ' + str(epI.bEndpointAddress))
print('ep xfer type ' + str(epI.bmAttributes))
# print('ep synch type ' + str(epI.bmAttributes[1]))
# print('ep Use type ' + str(epI.bmAttributes[2]))
print('ep max packet ' + str(epI.wMaxPacketSize))
print('ep interval ' + str(epI.bInterval))
print('epO length ' + str(epO.bLength))
print('ep desc type ' + str(epO.bDescriptorType))
print('ep address ' + str(epO.bEndpointAddress))
print('ep xfer type ' + str(epO.bmAttributes))
# print('ep synch type ' + str(epO.bmAttributes[1]))
# print('ep Use type ' + str(epO.bmAttributes[2]))
print('ep max packet ' + str(epO.wMaxPacketSize))
print('ep interval ' + str(epO.bInterval))
print('dev length ' + str(dev.bLength))
print('dev num configs ' + str(dev.bNumConfigurations))
print('dev class ' + str(dev.bDeviceClass))
assert epO is not None
assert epI is not None
msg = '2234567890123456' #first character is the command
print('writing to USB ->' + msg)
print(str(dev))
# dev.write(epO, msg, 100)
epO.write(msg)
print('reading from USB...')
ret = epI.read(16)
# ret = dev.read(2,len(msg),100) # device timeout is 50 ms,
sret = ''.join([chr(x) for x in ret])
print(sret)
# This is needed to release interface, otherwise attach_kernel_driver fails
# due to "Resource busy"
usb.util.dispose_resources(dev)
# It may raise USBError if there's e.g. no kernel driver loads
if reattach:
print('Reattaching Kernel Driver')
dev.attach_kernel_driver(renum)
这是在PI上执行时的响应：
Device located
configuration <usb.core.Configuration object at 0xb6a6e6d0>
detach <usb.core.Device object at 0xb6a6e750>: 0
epI length 7
ep desc type 5
ep address 129
ep xfer type 3
ep max packet 16
ep interval 50
epO length 7
ep desc type 5
ep address 2
ep xfer type 3
ep max packet 16
ep interval 50
dev length 18
dev num configs 1
dev class 0
writing to USB ->
<usb.core.Device object at 0xb6a6e750>
2234567890123456
reading from USB...
227.45,51.0 ## The first response has this after the last line above
## the second try gives this response instead:
Traceback (most recent call last):
File "./t8.py", line 78, in <module>
ret = epI.read(16)
File "/usr/local/lib/python2.7/dist-packages/usb/core.py", line 300, in read
return self.device.read(self.bEndpointAddress, size, self.interface, timeout)
File "/usr/local/lib/python2.7/dist-packages/usb/core.py", line 670, in read
self.__get_timeout(timeout)
File "/usr/local/lib/python2.7/dist-packages/usb/backend/libusb1.py", line 798, in intr_read
timeout)
File "/usr/local/lib/python2.7/dist-packages/usb/backend/libusb1.py", line 889, in __read
_check(retval)
File "/usr/local/lib/python2.7/dist-packages/usb/backend/libusb1.py", line 571, in _check
raise USBError(_str_error[ret], ret, _libusb_errno[ret])
usb.core.USBError: [Errno 110] Operation timed out
我搜索并发现我可以使用以下命令检查USB的USB消息：
grep usb /var/log/messages
我发现了这条消息：
Nov 3 02:16:06 raspberrypi kernel: [123725.144960] usb 1-1.3: usbfs: process 10698 (python) did not claim interface 0 before use
我添加了重新连接代码，然后就消失了 . 我搜索并发现其他人有问题，可能是pyUSB . 我更新到了b2版本 . 现在，设备打印命令在给出print（dev）命令时给出完整的HID报告打印输出 . 非常好，但设备超时的原始问题仍然存在，并且它看起来不像它与声称的接口有关 .
有关如何防止超时的任何见解，以便设备可以提供多组数据？
谢谢你的帮助 .