问题描述
我正在尝试使用python3和pyusb进行一些基本的USB通信，并且在写入USB设备时遇到了困难。经过大量研究，我开发了以下代码，可以识别并声明设备没有错误，但是在尝试写入设备时收到超时。我相信我使用了正确的端点（HID /接口0，无论如何都尝试了所有端点，但均未成功。）FWIW'* IDN？'是SCPI命令，我的愿望是简单地在设备中写入和读取SCPI（ASCII）字符串。
有关设备，收到的错误和示例代码的信息如下。事实证明，它们都在Buster / 10.4下的R-Pi3 +上运行。任何指针将不胜感激。谢谢。
尝试运行并收到错误：
pi@raspBerrypi:~/src $ sudo python3 test6.py
Ladybug device found
writing: *IDN?
Traceback (most recent call last):
File "test6.py",line 36,in <module>
dev.write(0x81,msg,1000)
File "/usr/local/lib/python3.7/site-packages/usb/core.py",line 982,in write
self.__get_timeout(timeout)
File "/usr/local/lib/python3.7/site-packages/usb/backend/libusb1.py",line 860,in intr_write
timeout)
File "/usr/local/lib/python3.7/site-packages/usb/backend/libusb1.py",line 938,in __write
_check(retval)
File "/usr/local/lib/python3.7/site-packages/usb/backend/libusb1.py",line 602,in _check
raise USBTimeoutError(_strerror(ret),ret,_libusb_errno[ret])
usb.core.USBTimeoutError: [Errno 110] Operation timed out
设备信息：
DEVICE ID 1a0d:15d8 on Bus 001 Address 004 =================
bLength : 0x12 (18 bytes)
bDescriptorType : 0x1 Device
bcdUSB : 0x200 USB 2.0
bDeviceClass : 0x0 Specified at interface
bDeviceSubClass : 0x0
bDeviceProtocol : 0x0
bMaxPacketSize0 : 0x40 (64 bytes)
idvendor : 0x1a0d
idProduct : 0x15d8
bcdDevice : 0x100 Device 1.0
iManufacturer : 0x1 LadyBug Technologies LLC
iProduct : 0x2 LB5908A
iSerialNumber : 0x3 189546
bNumConfigurations : 0x1
CONfigURATION 1: 500 mA ==================================
bLength : 0x9 (9 bytes)
bDescriptorType : 0x2 Configuration
wTotalLength : 0x47 (71 bytes)
bNumInterfaces : 0x2
bConfigurationValue : 0x1
iConfiguration : 0x0
bmAttributes : 0x80 Bus Powered
bMaxPower : 0xfa (500 mA)
INTERFACE 0: Human Interface Device ====================
bLength : 0x9 (9 bytes)
bDescriptorType : 0x4 Interface
bInterfaceNumber : 0x0
bAlternateSetting : 0x0
bNumEndpoints : 0x2
bInterfaceClass : 0x3 Human Interface Device
bInterfaceSubClass : 0x0
bInterfaceProtocol : 0x0
iInterface : 0x0
ENDPOINT 0x81: Interrupt IN ==========================
bLength : 0x7 (7 bytes)
bDescriptorType : 0x5 Endpoint
bEndpointAddress : 0x81 IN
bmAttributes : 0x3 Interrupt
wMaxPacketSize : 0x80 (128 bytes)
bInterval : 0x1
ENDPOINT 0x1: Interrupt OUT ==========================
bLength : 0x7 (7 bytes)
bDescriptorType : 0x5 Endpoint
bEndpointAddress : 0x1 OUT
bmAttributes : 0x3 Interrupt
wMaxPacketSize : 0x80 (128 bytes)
bInterval : 0x1
INTERFACE 1: Application Specific ======================
bLength : 0x9 (9 bytes)
bDescriptorType : 0x4 Interface
bInterfaceNumber : 0x1
bAlternateSetting : 0x0
bNumEndpoints : 0x3
bInterfaceClass : 0xfe Application Specific
bInterfaceSubClass : 0x3
bInterfaceProtocol : 0x1
iInterface : 0x0
ENDPOINT 0x82: Bulk IN ===============================
bLength : 0x7 (7 bytes)
bDescriptorType : 0x5 Endpoint
bEndpointAddress : 0x82 IN
bmAttributes : 0x2 Bulk
wMaxPacketSize : 0x200 (512 bytes)
bInterval : 0x0
ENDPOINT 0x2: Bulk OUT ===============================
bLength : 0x7 (7 bytes)
bDescriptorType : 0x5 Endpoint
bEndpointAddress : 0x2 OUT
bmAttributes : 0x2 Bulk
wMaxPacketSize : 0x200 (512 bytes)
bInterval : 0x0
ENDPOINT 0x83: Interrupt IN ==========================
bLength : 0x7 (7 bytes)
bDescriptorType : 0x5 Endpoint
bEndpointAddress : 0x83 IN
bmAttributes : 0x3 Interrupt
wMaxPacketSize : 0x40 (64 bytes)
bInterval : 0x1
代码：
import usb.core
import usb.util
import time
# find the device
dev = usb.core.find(idvendor=0x1a0d,idProduct=0x15d8)
# was it found?
if dev is None:
raise ValueError('Ladybug device not found')
else:
print ("Ladybug device found")
# required to detach device from OS,othewise I receive a 'device busy' error
for cfg in dev:
for intf in cfg:
if dev.is_kernel_driver_active(intf.bInterfaceNumber):
try:
dev.detach_kernel_driver(intf.bInterfaceNumber)
except usb.core.USBError as e:
sys.exit("Could not detatch kernel driver from interface({0}): {1}".format(intf.bInterfaceNumber,str(e)))
dev.set_configuration()
usb.util.claim_interface(dev,0)
data = ('null')
msg = "*IDN?\r\n"
print ("writing: " + msg)
# write the data
dev.write(0x81,1000)
print ("reading...")
data = dev.read(0x1,100,1000)
print (data)
解决方法
我认为应该是：
# write the data
dev.write(0x02,msg,1000) # bulk out
print ("reading...")`
data = dev.read(0x82,100,1000) # bulk in