Qt Serial Port (works ok on Mac, can't read on Windows only write)

hugofreitas

Hello,

I'm having a strange problem with qtserialport. I'll be thankful if someone help me solve this problem:

I'm not an expert in QT and STM.
I already search for this issue in several forums but I didn't have any luck.

Problem:

I'm trying to communicate with STM32F767
The port device is a virtual one.
STM is sending a package of data each 250 ms (~100bytes).
Using Mac OS I don't have problems with the code and readyRead() signal is trigger normally.
If I use Windows and run the app readyRead() is never triggered and if I try to readAll() no data is showed.
Write method is working.

Important note: Using Windows and after open and close the port with putty the app works normally. In these case readyRead() is triggered.

You can find bellow the setup code used:

firmware = new QSerialPort(this);
...
firmware -> setPortName(port);
firmware -> open(QIODevice::ReadWrite);
firmware -> setBaudRate(QSerialPort::Baud115200);
firmware -> setDataBits(QSerialPort::Data8);
firmware -> setFlowControl(QSerialPort::NoFlowControl);
firmware -> setParity(QSerialPort::NoParity);
firmware -> setStopBits(QSerialPort::OneStop);

connect(firmware, SIGNAL(readyRead()), this, SLOT(receivedata()));

Thank you for your help,
Hugo

aha_1980

Hi @hugofreitas,

firmware = new QSerialPort(this);

I guess firmware is a member variable ... right?

firmware -> open(QIODevice::ReadWrite);

Open returns a bool, check it!

Also, I'd move all the setBaudRate & co. calls before calling open.
Also, most of these calls have a return value to check.

Regarding the controller: does it have an internal USB-serial port or do you use an external chip (e.g. FTDI)?

Regards

hugofreitas

Thank you for your answer @aha_1980

@aha_1980 said in Qt Serial Port (works ok on Mac, can't read on Windows only write):

I guess firmware is a member variable ... right?

Yes!

@aha_1980 said in Qt Serial Port (works ok on Mac, can't read on Windows only write):

I guess firmware is a member variable ... right?

firmware -> open(QIODevice::ReadWrite);

Open returns a bool, check it!

Also, most of these calls have a return value to check.

Everything that can return bools returns a true state and without errors. (firmware -> error())

@aha_1980 said in Qt Serial Port (works ok on Mac, can't read on Windows only write):

Regarding the controller: does it have an internal USB-serial port or do you use an external chip (e.g. FTDI)?

Internal.

@aha_1980 said in Qt Serial Port (works ok on Mac, can't read on Windows only write):

Also, I'd move all the setBaudRate & co. calls before calling open.

I'll try this and come back later.

Regards,
Hugo