AbstractSerial *port = new AbstractSerial;
QByteArray a,b,inputBuffer;

QString *logText = new QString;


MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
 ui->setupUi(this);

 port->setDeviceName("/dev/ttyUSB0");
 connect( port, SIGNAL(readyRead()), this, SLOT(ReadData()));
 connect( port, SIGNAL(signalStatus(QString,QDateTime)), this, SLOT(State(QString,QDateTime)));

 if (port->open(AbstractSerial::ReadWrite))
     ui->label->setText("open!");

 port->reset();
 port->setBaudRate(AbstractSerial::BaudRate57600);
 port->setFlowControl(AbstractSerial::FlowControlOff);
 port->setDataBits(AbstractSerial::DataBits8);
 port->setParity(AbstractSerial::ParityNone);
 port->setStopBits(AbstractSerial::StopBits1);

 qDebug() << "= New parameters =";
 qDebug() << "Device name            : " << port->deviceName();
 qDebug() << "Baud rate              : " << port->baudRate();
 qDebug() << "Data bits              : " << port->dataBits();
 qDebug() << "Parity                 : " << port->parity();
 qDebug() << "Stop bits              : " << port->stopBits();
 qDebug() << "Flow                   : " << port->flowControl();
 qDebug() << "Char timeout, msec     : " << port->charIntervalTimeout();
 qDebug() << "open mode              : " << port->openMode();
 qDebug() << "port error             : " << port->errorString();
 qDebug() << "port lineStatus        : " << port->lineStatus();

}

void MainWindow::ReadData()
{
   if (!port->waitForReadyRead(500))
        qDebug() << "Response timeout.";
  qint64 ba_count= port->bytesAvailable();
   QByteArray ba = port->read(ba_count);

   inputBuffer.append(ba);
       if (inputBuffer.contains("\n"))                                 // Если пришёл конец строки
       {
           QString ba_str(inputBuffer);
           inputBuffer.clear();
         logText->append(QString("<b>></b> %1").arg(ba_str));       // Записываем посылаемые данные в лог
       }

    QString ba1_str(ba);
    qDebug () << "log    : "  << logText;
    qDebug () << "read   : "  << ba1_str;
}

void MainWindow::State(QString stateMsg,QDateTime dt)
{

  qDebug() << "State: " << stateMsg << ", in time: " << dt.time().toString();
}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::on_pushButton_clicked()
{


 port->write(ui->lineEdit->text().toAscii() +'/r');
 ui->lineEdit->clear();
// qDebug() << "port error             : " << port->errorString();
// qDebug() << "port line state        : " << port->lineStatus();

}

void MainWindow::on_pushButton_2_clicked()
{
  port->flush();
}