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QSerialPort: problem with waitForReadyRead()

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  • K kuzulis

    What is OS, and what is Qt version?

    O Offline
    O Offline
    oBOXPOH
    wrote on last edited by
    #6

    @kuzulis said in QSerialPort: problem with waitForReadyRead():

    What is OS, and what is Qt version?

    OS: Windows 10
    Qt Version: 5.13.1
    Building: MinGW 32-bit

    JonBJ J.HilkJ 2 Replies Last reply
    0
    • O oBOXPOH

      @kuzulis said in QSerialPort: problem with waitForReadyRead():

      What is OS, and what is Qt version?

      OS: Windows 10
      Qt Version: 5.13.1
      Building: MinGW 32-bit

      JonBJ Offline
      JonBJ Offline
      JonB
      wrote on last edited by
      #7

      @oBOXPOH
      Like I & @J-Hilk have said, suggest you at least try it with readyRead signal instead of waits and see if that makes the difference?

      O 1 Reply Last reply
      1
      • O oBOXPOH

        @kuzulis said in QSerialPort: problem with waitForReadyRead():

        What is OS, and what is Qt version?

        OS: Windows 10
        Qt Version: 5.13.1
        Building: MinGW 32-bit

        J.HilkJ Offline
        J.HilkJ Offline
        J.Hilk
        Moderators
        wrote on last edited by
        #8

        @oBOXPOH
        I would suggest to use a different Qt version QSerialPort has some serious issues in 5.13.1

        see this bugreport
        https://bugreports.qt.io/browse/QTBUG-78086


        Be aware of the Qt Code of Conduct, when posting : https://forum.qt.io/topic/113070/qt-code-of-conduct


        Q: What's that?
        A: It's blue light.
        Q: What does it do?
        A: It turns blue.

        O D 2 Replies Last reply
        4
        • J.HilkJ J.Hilk

          @oBOXPOH
          I would suggest to use a different Qt version QSerialPort has some serious issues in 5.13.1

          see this bugreport
          https://bugreports.qt.io/browse/QTBUG-78086

          O Offline
          O Offline
          oBOXPOH
          wrote on last edited by oBOXPOH
          #9

          @J-Hilk said in QSerialPort: problem with waitForReadyRead():

          @oBOXPOH
          I would suggest to use a different Qt version QSerialPort has some serious issues in 5.13.1

          see this bugreport
          https://bugreports.qt.io/browse/QTBUG-78086

          Tried Qt 5.9.8.

          In this case waitForReadyRead() always returns false with accepted write command.

          1 Reply Last reply
          0
          • JonBJ JonB

            @oBOXPOH
            Like I & @J-Hilk have said, suggest you at least try it with readyRead signal instead of waits and see if that makes the difference?

            O Offline
            O Offline
            oBOXPOH
            wrote on last edited by oBOXPOH
            #10

            @JonB said in QSerialPort: problem with waitForReadyRead():

            @oBOXPOH
            Like I & @J-Hilk have said, suggest you at least try it with readyRead signal instead of waits and see if that makes the difference?

            I tried next (all is inside the class):

            connect(deviceControl_SerialPort, &QSerialPort::readyRead, this, &Class::readData_slot);
            
            void Class::readData_slot()
            {
                qDebug() << "Ready Read" << endl;
                deviceControl_readData.append(deviceControl_SerialPort->readAll());
            }
            

            In this case I can't reach readData_slot() method.

            Then I tried next:

            connect(deviceControl_SerialPort, &QSerialPort::errorOccurred, this, &Class::serialPortError_slot);
            
            void Class::serialPortError_slot(QSerialPort::SerialPortError error)
            {
                qDebug() << error << endl;
            }
            
            

            and got some error (see log below):

            WRITTEN  1 
            
            READING... 
            
            QSerialPort::TimeoutError 
            
            WRITTEN  2 
            
            READING... 
            
            QSerialPort::TimeoutError 
            
            WRITTEN  3 
            
            QSerialPort::TimeoutError 
            
            I AM NOT READY! 
            
            Ready Read 
            
            Ready Read 
            

            and, by the way, message for readyRead signal. Strangely, that I got it only after 2 real readings...

            aha_1980A 1 Reply Last reply
            0
            • O oBOXPOH

              @JonB said in QSerialPort: problem with waitForReadyRead():

              @oBOXPOH
              Like I & @J-Hilk have said, suggest you at least try it with readyRead signal instead of waits and see if that makes the difference?

              I tried next (all is inside the class):

              connect(deviceControl_SerialPort, &QSerialPort::readyRead, this, &Class::readData_slot);
              
              void Class::readData_slot()
              {
                  qDebug() << "Ready Read" << endl;
                  deviceControl_readData.append(deviceControl_SerialPort->readAll());
              }
              

              In this case I can't reach readData_slot() method.

              Then I tried next:

              connect(deviceControl_SerialPort, &QSerialPort::errorOccurred, this, &Class::serialPortError_slot);
              
              void Class::serialPortError_slot(QSerialPort::SerialPortError error)
              {
                  qDebug() << error << endl;
              }
              
              

              and got some error (see log below):

              WRITTEN  1 
              
              READING... 
              
              QSerialPort::TimeoutError 
              
              WRITTEN  2 
              
              READING... 
              
              QSerialPort::TimeoutError 
              
              WRITTEN  3 
              
              QSerialPort::TimeoutError 
              
              I AM NOT READY! 
              
              Ready Read 
              
              Ready Read 
              

              and, by the way, message for readyRead signal. Strangely, that I got it only after 2 real readings...

              aha_1980A Offline
              aha_1980A Offline
              aha_1980
              Lifetime Qt Champion
              wrote on last edited by
              #11

              Hi @oBOXPOH,

              Qt is an event-driven framework. By using endless loops, wait routines you create problems if you don't know what you are exactly doing.

              You should use QSerialPort with signals and slots. An example is shown here: https://doc.qt.io/qt-5/qtserialport-terminal-example.html

              Regards

              Qt has to stay free or it will die.

              O 1 Reply Last reply
              5
              • aha_1980A aha_1980

                Hi @oBOXPOH,

                Qt is an event-driven framework. By using endless loops, wait routines you create problems if you don't know what you are exactly doing.

                You should use QSerialPort with signals and slots. An example is shown here: https://doc.qt.io/qt-5/qtserialport-terminal-example.html

                Regards

                O Offline
                O Offline
                oBOXPOH
                wrote on last edited by
                #12

                @aha_1980 said in QSerialPort: problem with waitForReadyRead():

                Hi @oBOXPOH,

                Qt is an event-driven framework. By using endless loops, wait routines you create problems if you don't know what you are exactly doing.

                You should use QSerialPort with signals and slots. An example is shown here: https://doc.qt.io/qt-5/qtserialport-terminal-example.html

                Regards

                Terminal Example also works badly -> https://forum.qt.io/topic/108848/terminal-example-for-qserialport-doesn-t-work-correctly

                O 1 Reply Last reply
                0
                • O oBOXPOH

                  @aha_1980 said in QSerialPort: problem with waitForReadyRead():

                  Hi @oBOXPOH,

                  Qt is an event-driven framework. By using endless loops, wait routines you create problems if you don't know what you are exactly doing.

                  You should use QSerialPort with signals and slots. An example is shown here: https://doc.qt.io/qt-5/qtserialport-terminal-example.html

                  Regards

                  Terminal Example also works badly -> https://forum.qt.io/topic/108848/terminal-example-for-qserialport-doesn-t-work-correctly

                  O Offline
                  O Offline
                  oBOXPOH
                  wrote on last edited by
                  #13

                  @oBOXPOH said in QSerialPort: problem with waitForReadyRead():

                  @aha_1980 said in QSerialPort: problem with waitForReadyRead():

                  Hi @oBOXPOH,

                  Qt is an event-driven framework. By using endless loops, wait routines you create problems if you don't know what you are exactly doing.

                  You should use QSerialPort with signals and slots. An example is shown here: https://doc.qt.io/qt-5/qtserialport-terminal-example.html

                  Regards

                  Terminal Example also works badly -> https://forum.qt.io/topic/108848/terminal-example-for-qserialport-doesn-t-work-correctly

                  Solution is to install 5.13.2 or more version of Qt.

                  1 Reply Last reply
                  2
                  • D Offline
                    D Offline
                    DiaaQTdev
                    wrote on last edited by
                    #14

                    @oBOXPOH Hello i am having the same exact problem with QT, i don't receive any output by triggering the readyread signal or by using the return value of waitForReadyRead(), is it really issue related to QT version??
                    => I do have 5.12 version of QT, i want to make sure that that is the problem before deciding to do an upgrade..

                    Thank you in advance for your reply!

                    1 Reply Last reply
                    0
                    • J.HilkJ J.Hilk

                      @oBOXPOH
                      I would suggest to use a different Qt version QSerialPort has some serious issues in 5.13.1

                      see this bugreport
                      https://bugreports.qt.io/browse/QTBUG-78086

                      D Offline
                      D Offline
                      DiaaQTdev
                      wrote on last edited by
                      #15

                      @J-Hilk Hello, is it really a QT bug for versions under 5.13?

                      J.HilkJ 1 Reply Last reply
                      0
                      • D DiaaQTdev

                        @J-Hilk Hello, is it really a QT bug for versions under 5.13?

                        J.HilkJ Offline
                        J.HilkJ Offline
                        J.Hilk
                        Moderators
                        wrote on last edited by
                        #16

                        @DiaaQTdev

                        iirc 5.12 should work fine, only 5.13 had the issues


                        Be aware of the Qt Code of Conduct, when posting : https://forum.qt.io/topic/113070/qt-code-of-conduct


                        Q: What's that?
                        A: It's blue light.
                        Q: What does it do?
                        A: It turns blue.

                        1 Reply Last reply
                        1
                        • D Offline
                          D Offline
                          DiaaQTdev
                          wrote on last edited by
                          #17

                          @J-Hilk Thank you for your reply, i had upgraded my QT and i still had the same issue, when i send one byte i don't receive any feedback from my device(readyRead is not triggered), it has to be more than one byte in order to receive something. do you please have any idea why is this happening?

                          J.HilkJ 1 Reply Last reply
                          0
                          • D DiaaQTdev

                            @J-Hilk Thank you for your reply, i had upgraded my QT and i still had the same issue, when i send one byte i don't receive any feedback from my device(readyRead is not triggered), it has to be more than one byte in order to receive something. do you please have any idea why is this happening?

                            J.HilkJ Offline
                            J.HilkJ Offline
                            J.Hilk
                            Moderators
                            wrote on last edited by
                            #18

                            @DiaaQTdev
                            Can you show your code?


                            Be aware of the Qt Code of Conduct, when posting : https://forum.qt.io/topic/113070/qt-code-of-conduct


                            Q: What's that?
                            A: It's blue light.
                            Q: What does it do?
                            A: It turns blue.

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