Serial communication error in Col VF61 with Iris carrier board

Hi all

I am trying to a simple serial receive communication. I have a Col VF61 and Iris Carrier board. I have written program in QT but it seems not to be working. On my development system I have a com port through which I have connected a null modem cable. Right now I do not have 10 pin female IDC to 9-pin male D-Sub RS-232 serial cable so I am using jumper wires. I have connected the 3rd pin of null modem cable to 3rd pin of X13 connector (Tx-Rx) and connected 5th pin to 9th pin (GND-GND). I am trying to send a data from cutecom installed on my ubuntu 16.04 but I am not able to receive the data on vf61 application.

Here is the code:

void MainWindow::SerialInit()
this->Serial = new QextSerialPort("/dev/ttyLP1", QextSerialPort::EventDriven);
qWarning("Serial Port active \n");

connect(Serial, SIGNAL(readyRead()), this, SLOT(SerialRead()));
qWarning("Slot connected \n");

QString serialData;
void MainWindow::SerialRead()
serialData = Serial->readAll();
qWarning("Data received successfully");


As you can see I have connected a signal which will call SerialRead when data is ready to receive. and then it will print the data on a label. I am getting the serial port active and slot connected message but not able to receive the data.

Is the setup I have used wrong.? How can I test a loopback test on iris.? Thanks



As you can see in the image, when ever I am sending data to the ColVf from ubuntu, I receive Data Received Successfully which means that the code is working fine. But the received data is not what I am sending. As you can see, I sent Hello World but only received llo wor. Can anyone please suggest me something about this behaviour. Thanks

I have managed to send data from ColVF61 but not able to receive. I am receiving some other char. Receuved data us corrupted

I suggest for you to have a look at the following article on our developer website and try an easy stty/echo type test first.

stty/echo type test is working fine. I read in one of the post in this forum that DMA is enabled by default which may result in data loss in rx. Is it true. How can we disable it.

Please see the UART Linux article.

Enable/Disable lpuart DMA mode one can set via kernel arguments “setenv defargs fsl_lpart.nodma=1/0”.

Also have a look at the /proc/tty/drivers/fsl_lpuart file while running the tests for tx/rx/overrun statistics.

Can you also check with the synchronous (blocking) alternative(waitForReadyRead) instead of using the asynchronous (non-blocking) alternative(readyRead).