i want to connect qt and device using UART cable (RS232C) in linux. so i writing code and making ui and operating ,but it does not work. i want to connecting when i click some button(ui) device turn on and connect. also i want to make a function that if i enter some command device cognize and execute. below is my code , someone help me please. <mainwindow.cpp> #include "mainwindow.h" #include "ui_mainwindow.h" #include <QtSerialPort/QSerialPort> #include <QMessageBox> #include <QObject> #include <QIODevice> #include <QDebug> QSerialPort serial; MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent), ui(new Ui::MainWindow) { QSerialPort*port=new QSerialPort(); port->setPortName("/dev/ttyUSB0"); port->setBaudRate(QSerialPort::Baud19200); port->setDataBits(QSerialPort::Data8); port->setParity(QSerialPort::NoParity); port->setStopBits(QSerialPort::OneStop); port->setFlowControl(QSerialPort::NoFlowControl); port->open(QIODevice::ReadWrite); ui->setupUi(this); serial = new QSerialPort(this); } MainWindow::~MainWindow() { delete ui; } void MainWindow::on_pushButton_connect_clicked() { port=new QSerialPort(); QObject::connect(port,SIGNAL(readyRead()),this, SLOT(on_pushButton_connect_clicked())); if(!port->open(QIODevice::ReadWrite)){ QMessageBox::information(this, tr("connect"), "serialcommunication start"); } else { QMessageBox::critical(this, tr("fail"), serial- >errorString()); } } void MainWindow::on_pushButton_disconnect_clicked() { port->close(); QMessageBox::information(this, tr("disconnect"), "serial communication end"); } <mainwindow.h> #ifndef MAINWINDOW_H #define MAINWINDOW_H #include <QMainWindow> #include <QtSerialPort/QSerialPort> #include <QMessageBox> #include <QIODevice> #include <QDebug> namespace Ui { class MainWindow; } class MainWindow : public QMainWindow { Q_OBJECT public: explicit MainWindow(QWidget *parent = 0); QSerialPort*serial; //plus QSerialPort*port; QWidget*main_widget; void readData(); ~MainWindow(); private slots: void on_pushButton_connect_clicked(); void on_pushButton_disconnect_clicked(); private: Ui::MainWindow *ui; }; #endif // MAINWINDOW_H <main.cpp> #include "mainwindow.h" #include <QApplication> #include <QSerialPort> #include <QSerialPortInfo> #include <QDebug> #include <QMessageBox> #include <QIODevice> int main(int argc, char *argv[]) { QApplication a(argc, argv); foreach(const QSerialPortInfo &info,QSerialPortInfo::availablePorts()){ QSerialPort serial; serial.setPort(info); if (serial.open(QIODevice::ReadWrite)) serial.close(); } MainWindow w; w.show(); return a.exec(); }

@ segtteee said in Qt serial communication using UART : additionaly to what @ sierdzio said, change your constructor from QSerialPort*port=new QSerialPort(); to port = new QSerialPort(); otherwise you config a new Variable instead of your member variable.

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Qt serial communication using UART

Solved Qt Creator and other tools

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aha_1980
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wrote on 12 Sept 2017, 09:26 last edited by

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@mrjj said in Qt serial communication using UART:

@aha_1980
Oh yes. sorry. i did miss. Clicked from locked thread. Should have read it all :)

No problem :) (And no need to delete your post)
Qt has to stay free or it will die.
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12 Sept 2017, 09:26