Issue with serial communication with Arduino

[Kira]

Yes, I have checked it many times and it the port is busy it give me error message.

[Kira]

@sierdzio : And one more thing when i try to run the application by keeping the baud rate as 1200
It gives me error of the serial port.
And when i run samples from serial monitor everything works fine

[sierdzio]

To be honest, I don't know how to help. Last time I used Arduino was a few years ago, I don't remember encountering similar issues.

[Kira]

@sierdzio :Can you please share any code, if available so that i can check the scenario with it.
Actually the same problem is observed in qt's examples so don't know how to proceed.

[aha_1980]

Hi @Kira :

And one more thing when i try to run the application by keeping the baud rate as 1200
It gives me error of the serial port.

You will need to show us more (initialization) code and the exact error message here...

void MainWindow::writeData(const QByteArray &data)
{
serial->flush();
serial->write(data);
}

Note: serial->flush() is not needed in most cases (the documentation also states this).

And if, then it would be more useful to have it after the serial->write(data);.

Can you verify that the data you send arrives at the Arduino?

[Kira]

@aha_1980 : You can refer to the terminal example in the qtcreator's example list
I am using the same example.
And i am using arduino leonardo, it program is in the given link.
Please let me know of any other detail if required

[aha_1980]

@Kira

You will need to show us [...] the exact error message here...

Can you verify that the data you send arrives at the Arduino?

[Kira]

@aha_1980 : I was searching on internet and came across an topic which co-relates to my issue.
Please have a look on the given link:
https://stackoverflow.com/questions/31560694/qt-serial-port-not-working

The serial error which i get when i connect with baud rate 1200 is as follows:

Critical Error: The I/0 operation has been aborted because of either a thread exit or an application request.

[SGaist]

Hi,

You should connect the errorOccured signal of your serial port and handle QSerialPort::ResourceError which would likely be close the port and open it again. Note that your arduino serial device might have had its name changed depending on the system.

[Kira]

@SGaist : One more thing i tried to communicate the same program using arduino uno and there is no issue with the program it works fine without any error any issue.
Currently i am using arduino leonardo for my project and i need to move on with the same device.
My python program and serial simulator program works fine with the board without giving any error and this scenario occur with qt program so just not able to figure out where exactly the problem is.

[Kira]

@SGaist : Thanks for your response. I tried to play with the terminal examples in qt example set and got the stuff working.
Following are the observations:

1. First you have to configure the port in the settings and set the flow control to RTS/CTS.
   Earlier was set to noflowcontrol.
2. Connect the port
   3.Disconnect the port
   4.Reconnect the port
   Note: The above approach implies when arduino is disconnected and reconnected or fresh program is burned into the arduino.
   Apart from that only step 1 and 2 was sufficient.

In case of Arudino uno only step 1 & 2 were required even after reconnecting and burning fresh program. May be because of the hardware specifications.
Wondering why i have to connect, disconnect and again reconnect to get it working and only hardware flow control is working.

[SGaist]

For the control flow, check your Arduino documentation regarding the serial port settings.

[Kira]

Ohk thanks a lot

[KerrySelect]

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[JensenPitt]

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