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通过 USB 连接 pyboard 时出现“无法获取端口 (tty/ttyACM0)”

tag-icon • tag-icon usb usb-modem tty modem-manager
通过 USB 连接 pyboard 时出现“无法获取端口 (tty/ttyACM0)”

当我通过 USB 插入 micropython（类似 Arduino 的微处理器板）时，它可以作为 USB 文件系统正常工作，但是我无法将其用作 TTY。

我正在使用 Ubuntu 14.4 64 位。

当我插入设备时，我在系统日志中收到以下信息：

Jun 20 22:01:24 halob ModemManager[801]: <info>  Creating modem with plugin 'Generic' and '1' ports
Jun 20 22:01:24 halob ModemManager[801]: <warn>  Could not grab port (tty/ttyACM0): 'Cannot add port 'tty/ttyACM0', unhandled serial type'
Jun 20 22:01:24 halob ModemManager[801]: <warn>  Couldn't create modem for device at '/sys/devices/pci0000:00/0000:00:1c.3/0000:04:00.0/usb3/3-2': Failed to find primary AT port

lusb -v 输出如下所示：

Bus 003 Device 050: ID f055:9800  
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.00
  bDeviceClass            0 (Defined at Interface level)
  bDeviceSubClass         0 
  bDeviceProtocol         0 
  bMaxPacketSize0        64
  idVendor           0xf055 
  idProduct          0x9800 
  bcdDevice            2.00
  iManufacturer           1 Micro Python
  iProduct                2 Pyboard Virtual Comm Port in FS Mode
  iSerial                 3 000000000011
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength           98
    bNumInterfaces          3
    bConfigurationValue     1
    iConfiguration          0 
    bmAttributes         0x80
      (Bus Powered)
    MaxPower              500mA
    Interface Association:
      bLength                 8
      bDescriptorType        11
      bFirstInterface         1
      bInterfaceCount         2
      bFunctionClass          0 (Defined at Interface level)
      bFunctionSubClass       0 
      bFunctionProtocol       0 
      iFunction               0 
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         2 Communications
      bInterfaceSubClass      2 Abstract (modem)
      bInterfaceProtocol      1 AT-commands (v.25ter)
      iInterface              0 
      CDC Header:
        bcdCDC               1.10
      CDC Call Management:
        bmCapabilities       0x00
        bDataInterface          2
      CDC ACM:
        bmCapabilities       0x02
          line coding and serial state
      CDC Union:
        bMasterInterface        1
        bSlaveInterface         2 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x82  EP 2 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0008  1x 8 bytes
        bInterval              32
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        2
      bAlternateSetting       0
      bNumEndpoints           2
      bInterfaceClass        10 CDC Data
      bInterfaceSubClass      0 Unused
      bInterfaceProtocol      0 
      iInterface              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x03  EP 3 OUT
        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     0x83  EP 3 IN
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0040  1x 64 bytes
        bInterval               0
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           2
      bInterfaceClass         8 Mass Storage
      bInterfaceSubClass      6 SCSI
      bInterfaceProtocol     80 Bulk-Only
      iInterface              0 
      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     0x01  EP 1 OUT
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0040  1x 64 bytes
        bInterval               0
Device Status:     0x0000
  (Bus Powered)

答案1

我创建了一个 /etc/udev/rules.d/49-micropython.rules 文件，其内容如下：

# f055:9800 - MicroPython board
ATTRS{idVendor}=="f055", ATTRS{idProduct}=="9800", ENV{ID_MM_DEVICE_IGNORE}="1"
ATTRS{idVendor}=="f055", ATTRS{idProduct}=="9800", ENV{MTP_NO_PROBE}="1"
SUBSYSTEMS=="usb", ATTRS{idVendor}=="f055", ATTRS{idProduct}=="9800", MODE:="0666"
KERNEL=="ttyACM*", ATTRS{idVendor}=="f055", ATTRS{idProduct}=="9800", MODE:="0666"

然后我执行：

sudo udevadm control --reload-rules

然后拔下并重新插入连接至 micropython 板的 USB 电缆。

在 14.04 下对我来说有效

答案2

就像建议的那样：https://e2e.ti.com/support/microcontrollers/msp430/f/166/t/714021?Linux-MSP432P401R-How-to-connect-dev-ttyACM0-on-restart

您也可以使用以下命令禁用 Ubuntu Modem Manager 服务：

sudo systemctl disable ModemManager.service

该服务有一个 30 秒的初始化过程，由于不是调制解调器，因此会导致 /dev/TTYACM0 上的设备失败。

即使在重新启动机器后，这在 Ubuntu 18.04 下仍然有效。

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