Question

我正在尝试与连接到我的Ubuntu 16系统的设备（Python ver 2.7.12）进行交互。当我尝试写入设备时，我会收到写入超时（类似于从设备读取）。

根据我所拥有的少量文档，HID接口在接口3中实现，除了标准端点（EP）0外，设备还支持EP4 IN（设备到主机）中断传输类型，以及EP5 OUT（主机到设备）中断传输类型。它还声明USB Bulk基于请求 - 响应消息对，消息格式为64字节，第一个字节为“操作码”。对于'get version'命令，操作码为0x02，其余部分被忽略。

我是Python和USB的新手，所以可能有这个错误，但我试图写入'OUT'接口，然后从'IN'界面读取。我注意到当我将设备插入Ubuntu系统时，我得到一个新设备/ dev / usb / hiddev0但似乎无法写入，因此尝试连接到接口3并获取输入/输出接口。另外我添加了我认为是对PYUSB_DEBUG的调用，但我没有看到任何更多的输出比没有它。

使用以下代码我看到设备，我得到一个IN / OUT接口，但写/读总是超时。我不知道我错过了什么。非常感谢你的帮助

import usb.core
import usb.util
from usb.core import *
import sys
import os
import binascii
import time
import serial    
import itertools


idV = 0x2abf
idP = 0x0505

# doesnt seem to write anything to log?!
os.environ['PYUSB_DEBUG'] = 'debug'
#os.environ['PYUSB_LOG_FILENAME'] = "pyusb.log" #never written


print "finding idVendor = {}, idProduct= {}".format(idV, idP)
device = usb.core.find(idVendor=idV, idProduct=idP)

if device is None:
    print ("Device not found")
    exit()


# free up the device from the kernal
for cfg in device:
    for intf in cfg:
        if device.is_kernel_driver_active(intf.bInterfaceNumber):
            try:
                device.detach_kernel_driver(intf.bInterfaceNumber)
            except usb.core.USBError as e:
                sys.exit("Could not detach kernel driver from interface({0}): {1}".format(intf.bInterfaceNumber, str(e)))

# try default conf
print "setting configuration"
device.set_configuration()
print "config set"

print "trying to claim device"
try:
    usb.util.claim_interface(device, 0)
    print "claimed device"
except usb.core.USBError as e:
    print "Error occurred claiming " + str(e)
    sys.exit("Error occurred on claiming")
print "device claimed"

# get enpoint instance
cfg = device.get_active_configuration()
print "***********"
for intf in cfg:
    print "intf= " + str(intf)
print "***********"

# from document:
# The HID interface is implemented on Interface 3, in addition to standard endpoint (er)0, the device supports
# EP4 IN (device to host) interrupt transfer type, and EP5 OUT (host to device) interrupt transfer type
#  Note: EP$ seems to come back as 0x84 while EP5 comes back as 0x05
intf = cfg[(3, 0)]

# get the BULK OUT descriptor
epo = usb.util.find_descriptor(
    intf,
    # match our first out endpoint
    custom_match= \
        lambda e: \
            usb.util.endpoint_direction(e.bEndpointAddress) == \
            usb.util.ENDPOINT_OUT)

assert epo is not None

# get the BULK IN descriptor
epi = usb.util.find_descriptor(
    intf,
    # match our first out endpoint
    custom_match= \
        lambda e: \
            usb.util.endpoint_direction(e.bEndpointAddress) == \
            usb.util.ENDPOINT_IN)

assert epi is not None

print "write the data"
# commands are 64 bytes long, first byte is command code, 02 is 'get version', it doesn't need any of the other bytes set
try:
    # don't think I can use [0x00]*63 because it will be all pointers to same object?, call them out to be safe
    test = [0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]
    mybuff = b'\x02\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
    #device.write(epo,mybuff,1)         #timeout on write
    #epo.write(mybuff)                  #timeout on write
    epo.write(mybuff.encode('utf-8'))   #timeout on write
except usb.core.USBError as e:
    print "Write USBError: " + str(e)
    sys.exit()

print "done writing"
print "try read?"
try:
    #info = device.read(0x84, 8)
    info = epo.read(epi.bEndpointAddress,epi.wMaxPacketSize)
except usb.core.USBError as e:
    print "Read USBError: " + str(e)
    sys.exit()

print "read: " + str(info)

输出：

finding idVendor = 10943, idProduct= 1285
setting configuration
config set
trying to claim device
claimed device
device claimed
***********
< skipping audio interfaces>
intf=     INTERFACE 3: Human Interface Device ====================
     bLength            :    0x9 (9 bytes)
     bDescriptorType    :    0x4 Interface
     bInterfaceNumber   :    0x3
     bAlternateSetting  :    0x0
     bNumEndpoints      :    0x2
     bInterfaceClass    :    0x3 Human Interface Device
     bInterfaceSubClass :    0x0
     bInterfaceProtocol :    0x0
     iInterface         :    0x8 PlaylistControl
      ENDPOINT 0x84: Interrupt IN ==========================
       bLength          :    0x7 (7 bytes)
       bDescriptorType  :    0x5 Endpoint
       bEndpointAddress :   0x84 IN
       bmAttributes     :    0x3 Interrupt
       wMaxPacketSize   :   0x40 (64 bytes)
       bInterval        :    0xa
      ENDPOINT 0x5: Interrupt OUT ==========================
       bLength          :    0x7 (7 bytes)
       bDescriptorType  :    0x5 Endpoint
       bEndpointAddress :    0x5 OUT
       bmAttributes     :    0x3 Interrupt
       wMaxPacketSize   :   0x40 (64 bytes)
       bInterval        :    0xa
***********
write the data
Write USBError: [Errno 110] Operation timed out

Answer 1

我认为您在测试代码时重复使用该设备，并且在执行多次时会出现问题。你应该使用

Weight: 100.0
Height: 2,0

Weight: 6.9
Height: 0.7

Weight: 43.2
Height: 1.2

代码末尾。尝试使用

usb.util.dispose_resources(device)

后

device.reset()

如果您怀疑之前的代码运行已关闭，则在使用该设备执行任何其他操作之前。

使用PyUSB从usb设备读取/写入时遇到问题（超时）

1 个答案: