Problem in reading data from the serial port to byte array

[prasad1001]

Hello all,
I am new to Qt and please excuse me for my English, am writing code to controll the finger print reader(R305 module) with serial communication. I am writing the data to device successfully but i am unable to get the data to a bytearray and failed to verify received data with my data.

The below is the code for reading and writing data...

void MainWindow::on_pushButton_clicked()
{
 
   const char enable[12]={0xEF,0X01,0XFF,0XFF,0XFF,0XFF,0X01,0X00,0X03,0X01,0X00,0X05};
 
   QByteArray data = QByteArray::fromRawData(enable, sizeof(enable));
 
   textEdit->setText(data);
   qDebug()<<"\n enabletext123:"<<textEdit->toPlainText();
 
   writeData(data);
 
}
 
void MainWindow::on_pushIdentity_clicked()
{
    const char identify[17]={0xef,0x01,0xff,0xff,0xff,0xff,0x01,0x00,0x08,0x1b,0x01,0x00,0x00,0x01,0x01,0x00,0x27};
 
    QByteArray data1 = QByteArray::fromRawData(identify, sizeof(identify));
    // port->write(data);
 
    textEdit->setText(data1);
    qDebug()<<"\n identytext1234:"<<textEdit->toPlainText();
 
    writeData(data1);
}
 
void MainWindow::writeData(const QByteArray &data)
{
 
    qDebug()<< port->write(data);
    qDebug()<<"write data:"<<data;
    for(int i=0;i<=5000;i++);
}
 
 
void MainWindow::readData()
{
    port->flush();
    QByteArray response=port->readAll();
    int count=response.size();
    qDebug()<<"\n no. of bytes read"<<response.count();
 
    textEdit->append(response)
 
    qDebug()<<"read data:"<<response;
}

void MainWindow::on_pushButton_clicked()
{

   const char enable[12]={0xEF,0X01,0XFF,0XFF,0XFF,0XFF,0X01,0X00,0X03,0X01,0X00,0X05};

   QByteArray data = QByteArray::fromRawData(enable, sizeof(enable));

   textEdit->setText(data);
   qDebug()<<"\n enabletext123:"<<textEdit->toPlainText();

   writeData(data);

}

void MainWindow::on_pushIdentity_clicked()
{
    const char identify[17]={0xef,0x01,0xff,0xff,0xff,0xff,0x01,0x00,0x08,0x1b,0x01,0x00,0x00,0x01,0x01,0x00,0x27};

    QByteArray data1 = QByteArray::fromRawData(identify, sizeof(identify));
    // port->write(data);

    textEdit->setText(data1);
    qDebug()<<"\n identytext1234:"<<textEdit->toPlainText();

    writeData(data1);
}

void MainWindow::writeData(const QByteArray &data)
{

    qDebug()<< port->write(data);
    qDebug()<<"write data:"<<data;
    for(int i=0;i<=5000;i++);
}


void MainWindow::readData()
{
    port->flush();
    QByteArray response=port->readAll();
    int count=response.size();
    qDebug()<<"\n no. of bytes read"<<response.count();

    textEdit->append(response)
 
    qDebug()<<"read data:"<<response;
}

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My debug output is showing like this...and the textEdit not displaying this garbage data...The problem is, i am not getting any idea that what is happing..but the reader is blinking when i press the enable button..

Starting /home/hari/Videos/qt_projects2/Fingerprint-build-Desktop-Debug/Fingerprint...
Number of serial ports: 1
Name: "ttyS0"
true ok
Baud rate: 9600
Data bits: 8
Stop bits: 1
Parity: 0
Flow control: 0
Read buffer size: 0

enabletext123: "�
����
"
12
write data: "�
����

no. of bytes read 8
read data: "�
����
no. of bytes read 4
read data: "
identytext1234: "�
����
"
17
write data: "�
����

no. of bytes read 8
read data: "�
����
no. of bytes read 8
read data: " U&
/home/hari/Videos/qt_projects2/Fingerprint-build-Desktop-Debug/Fingerprint exited with code 0


Please suggest some modifications to get the data understandable for me...ASAP...
Thanks in advance..

[Radek]

QByteArray data = QByteArray::fromRawData(enable, sizeof(enable));
 
textEdit->setText(data);

QByteArray data = QByteArray::fromRawData(enable, sizeof(enable));

textEdit->setText(data);

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The data will contain a pointer to enable. No conversion to a human-readable string here. The setText() will use a QString ctor QString( const QByteArray& ) most likely. Do not expect any conversion, too. Just expanding bytes to shorts. That's why you get the output you are getting.

You need to convert yourself. For example:

QByteArray data = QByteArray::fromRawData(enable, sizeof(enable));
QString    aux;
 
for( int i = 0; i < data.size(); i++ )
{
  aux.append(QChar(0x20));
  aux.append(QString::number(data.constData[i],16);
}
 
textEdit->setPlainText(aux);
qDebug()<<"\n enabletext123:"<<textEdit->toPlainText();
 
writeData(data);

QByteArray data = QByteArray::fromRawData(enable, sizeof(enable));
QString    aux;

for( int i = 0; i < data.size(); i++ )
{
  aux.append(QChar(0x20));
  aux.append(QString::number(data.constData[i],16);
}

textEdit->setPlainText(aux);
qDebug()<<"\n enabletext123:"<<textEdit->toPlainText();

writeData(data);

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and so on.

[prasad1001]

Thanks for the quick reply..i was followed your code and ...it works for me....

Thank you very much..