我有一个关于从板 ESP 连接到 USB 端口的问题。尽管我设置了驱动程序，但我无法连接到此端口。我使用 ESP-WROVER-KI。在 MacOS 10.14 上运行

Serial port /dev/ttyUSB0

Traceback (most recent call last):
  File "/Users/apple/esp/esp-idf/components/esptool_py/esptool/esptool.py", line 2959, in <module>
    _main()
  File "/Users/apple/esp/esp-idf/components/esptool_py/esptool/esptool.py", line 2952, in _main
    main()
  File "/Users/apple/esp/esp-idf/components/esptool_py/esptool/esptool.py", line 2652, in main
    esp = chip_class(each_port, initial_baud, args.trace)
  File "/Users/apple/esp/esp-idf/components/esptool_py/esptool/esptool.py", line 222, in __init__
    self._port = serial.serial_for_url(port)
  File "/Users/apple/Library/Python/2.7/lib/python/site-packages/serial/__init__.py", line 88, in serial_for_url
    instance.open()
  File "/Users/apple/Library/Python/2.7/lib/python/site-packages/serial/serialposix.py", line 268, in open
    raise SerialException(msg.errno, "could not open port {}: {}".format(self._port, msg))
serial.serialutil.SerialException: [Errno 2] could not open port /dev/ttyUSB0: [Errno 2] No such file or directory: '/dev/ttyUSB0'
make: *** [flash] Error 1

任何有连接 USB 端口经验的人都可以告诉我原因吗？