QIODevice::write: device not open

Matthacker

Hi

I have a problem with setting up my connection to a COM port have been stuck for awhile now hope you can help me.

Do I have to have my mbed controller connected for it to work ?

when i run my code it says:

bq.
Serial NOT Opened
error code = 1
error string = "No such file or directory"
QIODevice::write: device not open

the code I have is:
@

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "modify_scenario.h"
#include <QSerialPort>
#include <QDebug>
#include <QPushButton>
#include <QWidget>

MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{

 ui->setupUi(this);

 serial = new QSerialPort(this);
 serial->setPortName("COM2");
 if(serial->open(QIODevice::ReadWrite))
 {
     qDebug("Serial Opened");
     serial->setBaudRate(QSerialPort::Baud9600);
     serial->setDataBits(QSerialPort::Data8);
     serial->setParity(QSerialPort::NoParity);
     serial->setStopBits(QSerialPort::OneStop);
     serial->setFlowControl(QSerialPort::NoFlowControl);
 }
 else
 {
     qDebug ("Serial NOT Opened");
     qDebug() << "error code = " << serial->error();
     qDebug() << "error string = " << serial->errorString();
 }

 connect(serial,SIGNAL(readyRead()),this,SLOT(serialReceived()));

@

for the connect: (serialReceived())

@
void MainWindow::serialReceived()
{
QByteArray ba;
ba = serial -> readAll();
ui->label->setText(ba);
qDebug() << ba;
}
@

and in the header I have in private slots

@

void serialReceived();
@

and in private

@

private:
Ui::MainWindow *ui;
Modify_Scenario *modify;
int counter;
QSerialPort *serial;
@

really hope you can help me :)

Regards Alex.

kuzulis

This means that COM2 is not exists on your PC (you can check it in Device Manager).

Matthacker

Hi Kuzulis

Yes that is correct, checked it already.

does that mean I have to setup a virtual com port?
and how do I do that ?

if I input my device to my computer, then my computer detects a COM port, but wanted to test it without the device.

Alex.

SGaist

Hi and welcome to devnet,

Do you mean that you would like to make your code run even when there's no serial port available ?

Matthacker

used Eltima's virtual COM port to setup a virtual port and tested it with tera term and it works now :)