Use ctrl key to set/unset flag for poll feature

Ctrl key also changes the text of the button to "Poll"

src/mainwindow.cpp

@@ -47,7 +47,8 @@ extern MainWindow * globalMainWin;
 MainWindow::MainWindow( QWidget * _parent ) :
 	QMainWindow( _parent ),
 	ui( new Ui::MainWindowClass ),
-	m_modbus( NULL )
+	m_modbus( NULL ),
+	m_poll(false)
 {
 	ui->setupUi(this);
 
@@ -112,6 +113,28 @@ MainWindow::~MainWindow()
 	delete ui;
 }
 
+void MainWindow::keyPressEvent(QKeyEvent* event)
+{
+	if( event->key() == Qt::Key_Control )
+	{
+		//set flag to request polling
+		if( m_modbus != NULL )
+			m_poll = true;
+
+		ui->sendBtn->setText( tr("Poll") );
+	}
+}
+
+void MainWindow::keyReleaseEvent(QKeyEvent* event)
+{
+	if( event->key() == Qt::Key_Control )
+	{
+		m_poll = false;
+
+		ui->sendBtn->setText( tr("Send") );
+	}
+}
+
 void MainWindow::busMonitorAddItem( bool isRequest,
 					uint8_t slave,
 					uint8_t func,

src/mainwindow.h

@@ -89,11 +89,14 @@ private slots:
     void setStatusError(const QString &msg);
 
 private:
+    void keyPressEvent(QKeyEvent* event);
+    void keyReleaseEvent(QKeyEvent* event);
+
     Ui::MainWindowClass * ui;
     modbus_t * m_modbus;
     QWidget * m_statusInd;
     QLabel * m_statusText;
-
+    bool m_poll;
 };
 
 #endif // MAINWINDOW_H