Communication Arduino-C++ do not read Arduino

Question

I have the following code:

QSerialPort arduPort(\"COM5\");
arduPort.setBaudRate(QSerialPort::Baud9600);
arduPort.setDataBits(QSerialPort::Data8);
arduPort.se         


        

Answer 1

Setting the ports before open is not quite possible before Qt 5.2. The reason is that the original design was a bit too low-level for the class rather properly object oriented. I had been considered for a long-time whether to change it and in the end I actually decided to do so.

I have just submitted a change that is now under code review that will make your original concept work, too.

Here you can find the details:

Make it possible to set the port values before opening

The summary can be read here for the change:

Make it possible to set the port values before opening

This patch also changes the behavior of the open method. We do not use port detection anymore for good. It has been a broken concept, and it is very unlikely that anyone has ever relied on it. If anyone had done that, they would be in trouble anyway, getting noisy warnings needlessly and all that.

The other option was also considered to keep this behavior optionally as the default, but that would complicate the API too much without not much gain.

The default port settings are now also the sane 9600,8,N,1, and no flow control. Also please note that the serial port is closed automatically in the open method if any of the settings fails.

Please update your Qt version (at least to Qt 5.2) or you can backport the change yourself. Then, it is possible to write this code and actually it is even recommended:

QSerialPort arduPort("COM5");
arduPort.setBaudRate(QSerialPort::Baud9600);
arduPort.setDataBits(QSerialPort::Data8);
arduPort.setParity(QSerialPort::NoParity);
arduPort.setStopBits(QSerialPort::OneStop);
arduPort.setFlowControl(QSerialPort::NoFlowControl);
arduPort.open(QSerialPort::ReadWrite);