QSerialPort reads only one byte

[flammmable]

I connect TX/Rx contacts together. Then I send **IDN?*. My oscilloscop shows that all of 5 bytes are sent. But readAll returns a QByteArray with only first byte.

#include <QCoreApplication>
#include <QtSerialPort>


int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    printf("initialization...\n"); //debug
    QSerialPort serial;
    serial.setPortName("COM2");
    serial.setBaudRate(QSerialPort::Baud9600);
    serial.setDataBits(QSerialPort::Data8);
    serial.setParity(QSerialPort::NoParity);
    serial.setStopBits(QSerialPort::OneStop);
    serial.setFlowControl(QSerialPort::NoFlowControl);
    serial.open(QSerialPort::ReadWrite);

    QString sendData("*IDN?");
    printf("send data:    "); //debug
    printf(sendData.toUtf8()); //debug
    serial.write(sendData.toUtf8());
    serial.waitForBytesWritten(1000);
    serial.waitForReadyRead(1000);
    QByteArray receiveData = serial.readAll();
    printf("\nreceive data: "); //debug
    printf(receiveData.data()); //debug
    printf("\nreceive byts: "); //debug
    printf("%d\n", receiveData.size()); //debug
    serial.close();
    printf("end"); //debug

    return a.exec();
}

I use a USB-UART demoboard PL2302 from the WaveShare with PL2303TA IC. My enviornment is Windows 7 and Qt 5.10.0. Also I have test this code on a UAS-DB9M-02 USB-UART cable from the Gembird with the same behavior. Examples from LabVIEW works fine with PL2303. So I think it's a Qt problem.

What am I doing wrong?

[jsulm]

@flammmable said in QSerialPort reads only one byte:

readAll

You should not expect that it delivers you everything at once. You should rather connect a slot to readyRead signal, call readAll in that slot and accumulate the data in a buffer until you got everything.

[Ketan__Patel__0011]

This post is deleted!