I'm trying to read a serial port with the Qt SerialPort library. I can read the data using HyperTerminal.

In Qt I used the following code to try and do the same thing. Qt says the the port has been opened correctly, but for some reason, the bytesAvailable from the serial port is always 0.

serial.setPortName("COM20");

if (serial.open(QIODevice::ReadOnly))
    qDebug() << "Opened port " << endl;
else
    qDebug() << "Unable to open port" << endl;

serial.setDataBits(QSerialPort::Data8);

serial.setParity(QSerialPort::EvenParity);

serial.setBaudRate(QSerialPort::Baud115200);


qDebug() << "Is open?? " << serial.isOpen();


// Wait unit serial port data is ready
while (!serial.bytesAvailable())
{
    //qDebug() << serial.bytesAvailable()<<endl;
    continue;
}

QByteArray data = serial.read(100);

qDebug() << "This is the data -" << data << endl;

serial.close();

In comparison, MATLAB code with the same structure as the above code, successfully manages to read the serial port data

%Serial Port Grapher - Shurjo Banerjee

s = serial('COM20');
s.BaudRate = 460800;
s.Parity = 'even';

try 
    input('Ready to begin?');
catch
end


fopen(s);

fh = figure();
hold on;

t = 1;

 while (s.BytesAvailable <= 0)
        continue
 end
 a = fread(s, 1)

 old_t = 1;
 old_a = a;

while true

   if (s.BytesAvailable > 0)
        a = fread(s, 1)

        figure(fh)
        t = t + 1;
        plot([old_t t], [old_a a]);
        old_t = t;
        old_a = a;
    end
end

fclose(s);