我有一个使用FTDI芯片的USB设备，该设备可以在Linux中识别：
user@user:~/src/libftdi/build$ lsusb
Bus 009 Device 008: ID 0403:faf0 Future Technology Devices International, Ltd
或：
user@user:~$ lsusb -v -d 0403:faf0
Bus 009 Device 008: ID 0403:faf0 Future Technology Devices International, Ltd
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 2.00
bDeviceClass 0 (Defined at Interface level)
bDeviceSubClass 0
bDeviceProtocol 0
bMaxPacketSize0 8
idVendor 0x0403 Future Technology Devices International, Ltd
idProduct 0xfaf0
bcdDevice 6.00
iManufacturer 1 Thorlabs
iProduct 2 APT DC Motor Controller
iSerial 3 83836244
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 32
bNumInterfaces 1
bConfigurationValue 1
iConfiguration 0
bmAttributes 0xc0
Self Powered
MaxPower 0mA
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 2
bInterfaceClass 255 Vendor Specific Class
bInterfaceSubClass 255 Vendor Specific Subclass
bInterfaceProtocol 255 Vendor Specific Protocol
iInterface 2 APT DC Motor Controller
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x02 EP 2 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 0
Device Status: 0x0001
Self Powered
我已经安装了pylibftdi并弄清楚了如何列出它们
In [26]: dev.driver.list_devices()
Out[26]:
[('Thorlabs', 'APT DC Motor Controller', '83836244'),
('Thorlabs', 'APT DC Motor Controller', '83838416'),
('Thorlabs', 'APT DC Motor Controller', '83837686'),
('Thorlabs', 'APT DC Motor Controller', '83836852'),
('Thorlabs', 'APT DC Motor Controller', '83837812'),
('Thorlabs', 'APT DC Motor Controller', '83825518'),
('Thorlabs', 'APT DC Motor Controller', '83838377'),
('Thorlabs', 'APT DC Motor Controller', '83838379'),
('Thorlabs', 'APT DC Motor Controller', '83836769'),
('Thorlabs', 'APT DC Motor Controller', '83837688'),
('Thorlabs', 'APT DC Motor Controller', '83836926'),
('Thorlabs', 'APT DC Motor Controller', '83837767'),
('Thorlabs', 'APT DC Motor Controller', '83836887'),
('Thorlabs', 'APT DC Motor Controller', '83836737'),
('Thorlabs', 'APT DC Motor Controller', '83838436'),
('Thorlabs', 'APT DC Motor Controller', '83837639'),
('Thorlabs', 'APT DC Motor Controller', '83836040'),
('Thorlabs', 'APT DC Motor Controller', '83837769'),
('Thorlabs', 'Brushed Motor Controller', '27251492'),
('Thorlabs', 'Brushed Motor Controller', '27251539')]
In [1]: from pylibftdi import USB_PID_LIST, USB_VID_LIST, Device
In [2]: USB_PID_LIST.append(0xFAF0)
In [3]: dev = Device()
In [4]: dev.driver.libftdi_version()
Out[4]: libftdi_version(major=0, minor=0, micro=0, version_str='< 1.0 - no ftdi_get_library_version()', snapshot_str='unknown')
pylibusb的文档说，device_id属性可用于指定我要连接的设备：
| __init__(self, device_id=None, mode='b', encoding='latin1', interface_select=None, device_index=0, **kwargs)
| Device([device_id[, mode, [OPTIONS ...]]) -> Device instance
|
| represents a single FTDI device accessible via the libftdi driver.
| Supports a basic file-like interface (open/close/read/write, context
| manager support).
:param device_id: an optional serial number of the device to open.
| if omitted, this refers to the first device found, which is
| convenient if only one device is attached, but otherwise
| fairly useless.
这是我的简单代码，在其中创建两个实例dev1和dev2。对于dev2，我不指定device_id（因此没有特定的序列号），而对于dev1，我可以指定。我可以成功地与dev2通信，但不能与dev1通信：
>>>from pylibftdi import USB_PID_LIST, USB_VID_LIST, Device
>>>from struct import pack, unpack
>>>USB_PID_LIST.append(0xFAF0)
>>>command = pack('BBBBBB',0x05,0x00,0x00,0x00,0x50,0x01)
>>>dev2 = Device();
>>>dev2.baudrate = 115200;
>>>dev2.writelines(command);
>>>dev2.readline()
'\x06\x00T\x00\x81P\xc0z\xf2\x04TDC001\x00\x00\x10\x00\x03\x00\x02\x00TDC001 DC Servo Drive\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\x00104927Apr\x00\x01\x00\x02\x00\x00\x00\x01\x00'
>>>dev1 = Device(device_id = '83838416');
>>>dev1.baudrate = 115200;
>>>dev1.writelines(command);
>>>dev1.readline()
''
由于我将许多USB设备连接到一台计算机，因此能够创建实例并与已定义序列号的设备进行通讯对我来说至关重要。
我不确定这是一个错误还是做错了什么。
稍后添加：
以某种方式取决于历史。如果我在重新启动python之后运行相同的代码，则会得到一个空字符串作为响应。我不知道我现在在做什么与以前不同。
In [1]: from pylibftdi import USB_PID_LIST, USB_VID_LIST, Device
In [2]: from struct import pack, unpack
In [3]: USB_PID_LIST.append(0xFAF0)
In [4]: command = pack('BBBBBB',0x05,0x00,0x00,0x00,0x50,0x01)
In [5]: dev2 = Device();dev2.baudrate = 115200;dev2.writelines(command);dev2.readline();
In [6]: dev2.__dict__
Out[6]:
{'_baudrate': 115200,
'_opened': True,
'ctx': <ctypes.c_char_Array_1024 at 0x7ff2008a1b00>,
'decoder': <encodings.latin_1.IncrementalDecoder at 0x7ff2006906d0>,
'device_id': None,
'device_index': 0,
'driver': <pylibftdi.driver.Driver at 0x7ff200690610>,
'encoder': <encodings.latin_1.IncrementalEncoder at 0x7ff200681f90>,
'encoding': 'latin1',
'fdll': <CDLL 'libftdi.so.1', handle 5627c1668650 at 7ff2011d08d0>,
'interface_select': None,
'mode': 'b'}
In [8]:
答案 0 :(得分：2)
您仅对uart（类似）模式感兴趣吗？如果是这样，您可以看看pyserial。尤其是serial.tools.list_ports.comports（）函数：
import serial
import serial.tools.list_ports
print([(x.device,x.hwid,x.description,x.location,x.serial_number) for x in serial.tools.list_ports.comports()])
这样，您也许可以获取正确的描述，然后通过
打开端口ports = [x.device for x in serial.tools.list_ports.comports() if search_string in x.hwid]
serial.Serial(ports[0], 115200)