Cannot open port on Windows XP

GoogleCodeExporter commented 9 years ago

What steps will reproduce the problem?
1. Write a simple app.
2. Try to open the com port.
3.

What is the expected output? What do you see instead?
m_port->open(QIODevice::ReadWrite) = false ALWAYS

What version of the product are you using? On what operating system?
1.2 beta1

Please provide any additional information below.
    m_port = new QextSerialPort(portName, QextSerialPort::Polling);
    m_port->setBaudRate(BAUD19200);
    m_port->setFlowControl(FLOW_OFF);
    m_port->setParity(PAR_NONE);
    m_port->setDataBits(DATA_8);
    m_port->setStopBits(STOP_2);
    m_port->setTimeout(500);

In linux everything works fine. When cross compiling on Linux for Windows and 
run the app in Windows XP I can't get the port to open, port enumeration works 
fine though.
The XP user has admin rights.

I don't use the port for serial communication rather than bitbanging to create 
a I2C host interface that works fine on Linux.

Original issue reported on code.google.com by applyser...@gmail.com on 20 Jun 2012 at 10:16

GoogleCodeExporter commented 9 years ago

Looks rather strange, return value of open() only affected by Windows API: 
CreateFile.

You can write a simple program to test the return value of:

  CreateFileW(L"COM1", GENERIC_READ|GENERIC_WRITE, 0, NULL, OPEN_EXISTING, 0, NULL);

to see whether it equals INVALID_HANDLE_VALUE or not.

If you can find the problem, then we can fix it. Thanks.

Original comment by dbzhang...@gmail.com on 21 Jun 2012 at 12:43

GoogleCodeExporter commented 9 years ago

similar issue

We have a virtual com, in XP being opened by "Sealevel  TCIP to serial 
converter".  It does not report the virtual com to the device manger. We can 
not see the port in QT.  But we cam see the data on the virtual com with a raw 
data display "PUTTY" or hypterm. 

help

Original comment by emihol...@gmail.com on 2 Sep 2014 at 5:52

lemanhtrung / qextserialport

Cannot open port on Windows XP #136