python3操作USB设备
本文以读取USB无线测量设备数据举例说明。需要用到pyusb模块和libusb-1.0.dll，详细说明如下。
一、配置libusb-1.0.dll
下载libusb-1.0.22.7z，根据操作系统来选择对应的动态库，如下：
-
32位操作系统：复制MS32\dll\libusb-1.0.dll到C:\Windows\SysWOW64
-
64位操作系统：复制 MS64\dll\libusb-1.0.dll到C:\Windows\System32
二、安装USB驱动
- 打开zadig-2.5.exe
- 选择菜单：Options->List All Devices，列出当前电脑所有USB设备，键盘和鼠标USB设备不用考虑
- 在设备列表中选择USB设备，点击“Replace Driver”按钮安装USB驱动
三、查询USB设备的idVendor和idProduct
- 打开zadig-2.5.exe
- 选择菜单：Options->List All Devices，列出当前电脑所有USB设备，键盘和鼠标USB设备不用考虑
- USB ID后面的两个值，分别对应：idVendor和idProduct
四、代码
- 查询所有USB设备信息
def get_usb_devlists():
all_devs = usb.core.find(find_all=True)
dev_list = []
for d in all_devs:
key = '{0}{1}'.format(hex(d.idVendor), hex(d.idProduct))
try:
dev_u = usb.core.find(idVendor=d.idVendor, idProduct=d.idProduct)
dev_u.reset()
if dev_u:
dev_u.set_configuration() # added this line
cfg = dev_u.get_active_configuration() # exception: access violation writing 0x0000000000000000
intf = cfg[(0, 0)]
ep = intf[0]
dev_list.append(key)
if key in CUsb.dev_dict: # 避免重复加入
continue
CUsb.dev_dict[key] = {
'idVendor': d.idVendor, 'idProduct': d.idProduct, 'thread': False}
except Exception as e:
err_str = str(e)
print("error!", err_str)
- 读取USB设备数据
def __init__(self, VID: int=None, PID: int=None, dev=None, ep=None):
self.VID = VID
self.PID = PID
self.dev_u = None
self.ep = None
if VID and PID:
try:
self.dev_u = usb.core.find(idVendor=VID, idProduct=PID)
if self.dev_u:
# get the configuration
self.dev_u.set_configuration() # added this line
cfg = self.dev_u.get_active_configuration()
# get interface 0
intf = cfg[(0, 0)]
# print(self.dev_u)
# get endpoints 1
self.ep = intf[0]
else:
print("Can't find device!")
except Exception as e:
print('__init__: ', e)
def read_data(self):
if not self.ep:
return []
key_dict = {
30: '1', 31: '2', 32: '3', 33: '4', 34: '5', 35: '6', 36: '7', 37: '8', 38: '9',
39: '0', 40: '\n', 55: '.'}
result_list = []
data = []
n = 0
inter = 16
while (40 not in data) or n < 1: # 40表示'\n'，是数据截止符
n += 1
try:
if self.ep:
data += self.ep.read(8, 1000) # timeout：1000毫秒
except Exception as e:
err_str = str(e)
# print('-----------------------', err_str)
count = len(data)
# print(count, len(data), data)
tmp_data = [data[i:i + inter] for i in range(0, count, inter)]
# print(self.ep.bEndpointAddress, len(tmp_data), tmp_data)
result_list.append('') # 创建初始值
for idx, tmp in enumerate(tmp_data):
data_str = self.get_value_form_8_byte(tmp)
if data_str == '\n': # 截止符
result_list[-1] += data_str
if idx < len(tmp_data)-1: # 处理下一个，创建初始值
result_list.append('')
continue
if (data_str == '' or data_str == '0') and result_list[-1] == '': # 过滤数字前面的0
continue
result_list[-1] += data_str
result_list[-1] = ('0' + result_list[-1]) if (result_list[-1][0] == '.') else result_list[-1] # 处理小数点前面没有0的情况
return [i for i in result_list if ('\n' in i) and ('.' in i)] # 丢掉异常数据