serial communication

[semden]

Hi everybody. Iam working with serial communication , using qextserialport library on QT 4.4.3 intergrated with visual studio 2005.
I have been able to successfully configure the library and try out an example QESPTA , which is able to recieve data from an embedded system to the computer running the QESPTA example.
Iam able to recieve data when i click on the open and recieve buttons, my problem is that i want to continously recieve data as long as it is available on the port , not just by clicking the recieve buttom.

I need some guidance.

[Cruz]

You need to write either a thread that runs in the background and collects the data, or use a QTimer to periodically poll the serial port. The threaded version looks something like this:

setupTheSerialPortJustLikeInQESPTA();
 
while (true)
{
   receiveData();
   msleep(100);
}
 
void receiveData()
{
      // Check if there is any data to read.
      if (!port->bytesAvailable())
            return -1;
 
      // Read as much data as you can from the port.
      bytesRead = port->read(receiveBuffer, qMin(port->bytesAvailable(), BUFFER_SIZE));
}

setupTheSerialPortJustLikeInQESPTA();

while (true)
{
   receiveData();
   msleep(100);
}

void receiveData()
{
      // Check if there is any data to read.
      if (!port->bytesAvailable())
            return -1;

      // Read as much data as you can from the port.
      bytesRead = port->read(receiveBuffer, qMin(port->bytesAvailable(), BUFFER_SIZE));
}

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With the QTimer solution you don't have an infinite loop with a sleep, but you call receiveData() with a timer instead.

A blocking approach that tries to read from the port and waits until data arrives would be preferable, but I couldn't make that work because of a problem with waitForReadyRead().

[semden]

Thanks , i will try it now and see how it works