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32F746GDISCOVERY's Virtual COM Port not listed (ST-LINK/V2-1)

AZane.1
Associate II

Hello! I am trying to access the Virtual COM Port of my 32F746GDISCOVERY' board. Unfortunately, the the COM port is not listed correctly in my system (Ubuntu 16.04). This is the output of "lsusb -v"

Bus 001 Device 012: ID 0483:3752 STMicroelectronics 
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.00
  bDeviceClass          239 Miscellaneous Device
  bDeviceSubClass         2 ?
  bDeviceProtocol         1 Interface Association
  bMaxPacketSize0        64
  idVendor           0x0483 STMicroelectronics
  idProduct          0x3752 
  bcdDevice            1.00
  iManufacturer           1 STMicroelectronics
  iProduct                2 STM32 STLink
  iSerial                 3 066CFF535651727067063241
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength          105
    bNumInterfaces          3
    bConfigurationValue     1
    iConfiguration          0 
    bmAttributes         0x80
      (Bus Powered)
    MaxPower              500mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           3
      bInterfaceClass       255 Vendor Specific Class
      bInterfaceSubClass    255 Vendor Specific Subclass
      bInterfaceProtocol    255 Vendor Specific Protocol
      iInterface              4 ST-Link Debug
      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
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x82  EP 2 IN
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0020  1x 32 bytes
        bInterval               0
    Interface Association:
      bLength                 8
      bDescriptorType        11
      bFirstInterface         1
      bInterfaceCount         2
      bFunctionClass          2 Communications
      bFunctionSubClass       2 Abstract (modem)
      bFunctionProtocol       1 AT-commands (v.25ter)
      iFunction               6 ST-Link VCP Ctrl
    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              6 ST-Link VCP Ctrl
      CDC Header:
        bcdCDC               1.10
      CDC Call Management:
        bmCapabilities       0x00
        bDataInterface          2
      CDC ACM:
        bmCapabilities       0x06
          sends break
          line coding and serial state
      CDC Union:
        bMasterInterface        1
        bSlaveInterface         2 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x84  EP 4 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0008  1x 8 bytes
        bInterval             255
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        2
      bAlternateSetting       0
      bNumEndpoints           2
      bInterfaceClass        10 CDC Data
      bInterfaceSubClass      0 Unused
      bInterfaceProtocol      0 
      iInterface              7 ST-Link VCP Data
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x05  EP 5 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     0x85  EP 5 IN
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0040  1x 64 bytes
        bInterval               0
Device Status:     0x0000
  (Bus Powered)

which seem OK to me. However, "dmesg | grep tty" shows

[    0.000000] console [tty0] enabled
[    1.216778] tty ttyS8: hash matches
[    5.016946] cdc_acm 1-1:1.2: ttyACM0: USB ACM device
[   50.552564] cdc_acm 1-1:1.2: ttyACM0: USB ACM device
[  117.338140] cdc_acm 1-1:1.2: ttyACM0: USB ACM device
[  313.987037] cdc_acm 1-1:1.2: ttyACM0: USB ACM device
[ 1255.781209] cdc_acm 1-1:1.1: ttyACM0: USB ACM device
[ 1280.179821] cdc_acm 1-1:1.1: ttyACM0: USB ACM device
[ 1419.712027] cdc_acm 1-1:1.1: ttyACM0: USB ACM device
[ 1452.144266] cdc_acm 1-1:1.1: ttyACM0: USB ACM device

with no "ttyUSB*" entry. Any clue? :)

1 ACCEPTED SOLUTION

Accepted Solutions
KnarfB
Principal III

the descriptors are fine, I get the same. You should see ttyACM0 which you can use:

$ ls -l /dev/serial/by-id/usb-STMicroelectronics_STM32_STLink_* 
lrwxrwxrwx 1 root root 13 Dec 19 12:09 /dev/serial/by-id/usb-STMicroelectronics_STM32_STLink_066DFF303739465043112657-if01 -> ../../ttyACM0

hth

KnarfB

View solution in original post

2 REPLIES 2
KnarfB
Principal III

the descriptors are fine, I get the same. You should see ttyACM0 which you can use:

$ ls -l /dev/serial/by-id/usb-STMicroelectronics_STM32_STLink_* 
lrwxrwxrwx 1 root root 13 Dec 19 12:09 /dev/serial/by-id/usb-STMicroelectronics_STM32_STLink_066DFF303739465043112657-if01 -> ../../ttyACM0

hth

KnarfB

AZane.1
Associate II

Thanks @KnarfB​! I think I simply had an unrelated issue with the communication over UART.