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Cannot open Serial Port using CuteCom

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  • H Offline
    H Offline
    houmingc
    wrote on last edited by
    #1

    I am using Cutecom to connect to my device
    When i "open device", Error "could not open /dev/ttyUSB0

    sudo apt-get install cutecom
    may i know where is cutecom installed. <Which CuteCom not working>

    Finding ports ttyUSB0 connected
    dmesg |grep tty shows ttyUSB0 connected
    usb 2-1.3:pl203 now attached to ttyUSB0

    I have check with lsusb, and device is connected

    I set the baud rate, data bits, stops bits and hex input at the right bottom.
    I tried with minicom, but i can't open serial port too

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    • SGaistS Offline
      SGaistS Offline
      SGaist
      Lifetime Qt Champion
      wrote on last edited by
      #2

      Hi,

      Not really a Qt question but anyway, do you have the rights to access your device ?

      Interested in AI ? www.idiap.ch
      Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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      • H Offline
        H Offline
        houmingc
        wrote on last edited by
        #3

        sudo chmod a+rw /dev/ttyUSB0

        works

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        • SGaistS Offline
          SGaistS Offline
          SGaist
          Lifetime Qt Champion
          wrote on last edited by
          #4

          And that's a security hole wide open.

          You should rather add your user to the correct group.

          Interested in AI ? www.idiap.ch
          Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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          • H Offline
            H Offline
            houmingc
            wrote on last edited by
            #5

            It is troublesome to run this command everytimes.
            Is there other alternatives?

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            • SGaistS Offline
              SGaistS Offline
              SGaist
              Lifetime Qt Champion
              wrote on last edited by
              #6

              Yes there is. What I suggested in my last message

              Interested in AI ? www.idiap.ch
              Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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              • H Offline
                H Offline
                houmingc
                wrote on last edited by
                #7

                I do not know what is the benefit of doing so.
                Below is the steps on 'how to add user to correct Group'?
                What is the difference between primary and secondary group

                @
                First, list all group $ cut -d: -f1 /etc/group
                Second, login as root user, $ su -
                Third, add user: $ sudo adduser new_username
                & add group: $ groupadd groupname
                & add user into group $ useradd -G groupname new_username
                Fouth, grant sudo privilege $visudo
                below root, add newuser ALL=(ALL:ALL) ALL
                Fifth, save and closed Ctrl + X
                @

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                • SGaistS Offline
                  SGaistS Offline
                  SGaist
                  Lifetime Qt Champion
                  wrote on last edited by
                  #8

                  The benefit ? You don't allow everybody and anybody the rights to access the serial port.

                  The secondary groups are just the additional groups your user is part of e.g. dial out

                  @useradd -G dialout username@
                  is a bit simpler

                  Interested in AI ? www.idiap.ch
                  Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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                  • H Offline
                    H Offline
                    houmingc
                    wrote on last edited by
                    #9

                    CuteCom can always open serial port but Qt program open serial port sometimes. What is the solution

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                    • SGaistS Offline
                      SGaistS Offline
                      SGaist
                      Lifetime Qt Champion
                      wrote on last edited by
                      #10

                      Is there a pattern when it fails to open the device ? Did you check if there's an error message returned by QSerialPort ?

                      Interested in AI ? www.idiap.ch
                      Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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