Qextserial on debian linux and readyRead slot

Hi All,
I would like to use Qextserial in debian linux with readyRead signal. There is no error on init, but it cannot send signal.
Here is my settings:

Code:

---

mSerialPort = new QextSerialPort("/dev/ttyUSB0", QextSerialPort::EventDriven);
    mSerialPort->setBaudRate(BAUD921600);
    mSerialPort->setDataBits(DATA_8);
    mSerialPort->setStopBits(STOP_1);
    mSerialPort->setParity(PAR_NONE);
    mSerialPort->setFlowControl(FLOW_OFF);
    mSerialPort->setQueryMode(QextSerialPort::EventDriven);
    mSerialPort->setRts(true);
    mSerialPort->setDtr(true);
 
    QObject::connect(mSerialPort, SIGNAL(readyRead()), this, SLOT(dataAvailable()));
    mSerialPort->open(QIODevice::ReadWrite);
    if (!mSerialPort->isOpen())
        log_exception(PacketDriverException, "cannot open %s", "/dev/ttyUSB0");

---

I read a post here

http://www.qtcentre.org/threads/1562...th-readyRead()

from 2008, it said I can' t use signal in linux :(
Is it true?
How can I set to use signals?

thx a lot
Zamek

Hi,

This is a deprecated library. Use QtSerialPort instead that is developed by Qt team. It is a part of Qt 5 and also can be used on Qt 4 as a module.

Quote:

---

Originally Posted by ^NyAw^

Hi,

This is a deprecated library. Use QtSerialPort instead that is developed by Qt team. It is a part of Qt 5 and also can be used on Qt 4 as a module.

---

Thx for your response. I changed to QtSerialPort, but unfortunately it doesn't works:(
QExtSerial can read but didn't send signal, QtSerial doesn't read in polling mode:(

There is hardware which sends 80bytes of frames with 921600 8N1 no flow.
Here is the code which I tried:

Code:

---

mSerialPort.setPortName("/dev/ttyUSB0");
    mSerialPort.open(QIODevice::ReadWrite);
 
    if (!mSerialPort.isOpen())
       log_exception(PacketDriverException, "cannot open %s", "/dev/ttyUSB0");
 
    if (! (mSerialPort.setBaudRate(921600, QSerialPort::AllDirections) &&
        mSerialPort.setDataBits(QSerialPort::Data8) &&
        mSerialPort.setStopBits(QSerialPort::OneStop) &&
        mSerialPort.setParity(QSerialPort::NoParity) &&
        mSerialPort.setFlowControl(QSerialPort::NoFlowControl)))
            log_exception(PacketDriverException, "cannot set params of %s", "/dev/ttyUSB0");
 
    mSerialPort.clearError();
    mSerialPort.flush();
    mSerialPort.clear(QSerialPort::AllDirections);
 
    QObject::connect(&mSerialPort, SIGNAL(readyRead()), this, SLOT(dataAvailable()));
    QObject::connect(&mSerialPort, SIGNAL(error(QSerialPort::SerialPortError)), this, SLOT(error()));
    QByteArray b = mSerialPort.readAll();
    std::cout<<b.size()<<std::endl;

---

There is no error and data comings to port. Size of b is 0.
What did I do wrong?

thx
Zamek

Code:

---

YourClass::dataAvailable()
{
    QByteArray b = mSerialPort.readAll();
    std::cout<<b.size()<<std::endl;
}

---

Hi,

Quote:

---

Originally Posted by kuzulis

Code:

---

YourClass::dataAvailable()
{
    QByteArray b = mSerialPort.readAll();
    std::cout<<b.size()<<std::endl;
}

---

---

Yes my dataAvailable is:

Code:

---

void PacketDriver::dataAvailable()
{
    if (mSerialPort.isReadable())
        readChar(mSerialPort.readAll());
}
 
void PacketDriver::error()
{
    QString err=mSerialPort.errorString();
    qDebug()<<err;
    mSerialPort.clearError();
}

---

but I use readAll at end of open, because there is no signal. After I open the port and there are incoming data I have to read something with readAll.
I started this with QExtSerial, which can read after open, but it cannot send signals. QtSerial cannot read after open and cannot send signal:(
The hardware continuously send 80 bytes of frames at every 5 ms. Cutecom and gtkterm can read it.

So, the readyRead() signal does not emitted never? Can you test it with use the Terminal example from the QtSerialPort?

Quote:

---

Originally Posted by kuzulis

So, the readyRead() signal does not emitted never? Can you test it with use the Terminal example from the QtSerialPort?

---

Hi Kuzulis,

creaderasync example works well. And I try to modify it, because it passing QSerialPort as a pointer in constructor, but I need to instantiate QSerialport in my constructor.
There is the problem, because when I try to instantiate in constructor it doesn't works, but no error!

Here is my test version:

Code:

---

#include "serialportreader.h"
 
#include <QCoreApplication>
#include <iostream>
 
QT_USE_NAMESPACE
 
#ifdef TEST
SerialPortReader::SerialPortReader(QObject *parent)
#else
SerialPortReader::SerialPortReader(QSerialPort *serialPort, QObject *parent)
#endif
    : QObject(parent)
#ifndef TEST
    , m_serialPort(serialPort)
#endif
    , m_standardOutput(stdout)
{
#ifdef TEST
    m_serialPort = new QSerialPort();
 
    if (!m_serialPort->open(QIODevice::ReadWrite))
        return;
 
    if (!m_serialPort->setBaudRate(921600))
        return;
 
    if (!m_serialPort->setDataBits(QSerialPort::Data8))
        return;
 
    if (!m_serialPort->setParity(QSerialPort::NoParity))
        return;
 
    if (!m_serialPort->setStopBits(QSerialPort::OneStop))
        return;
 
    if (!m_serialPort->setFlowControl(QSerialPort::NoFlowControl))
        return;
#endif
    connect(m_serialPort, SIGNAL(readyRead()), SLOT(handleReadyRead()));
    connect(m_serialPort, SIGNAL(error(QSerialPort::SerialPortError)), SLOT(handleError(QSerialPort::SerialPortError)));
}
 
SerialPortReader::~SerialPortReader()
{
}
 
void SerialPortReader::handleReadyRead()
{
    m_readData = m_serialPort->readAll();
    std::cout<<"read, size:"<<m_readData.length()<<std::endl;
 
    if (!m_timer.isActive())
        m_timer.start(5000);
}
 
void SerialPortReader::handleTimeout()
{
    if (m_readData.isEmpty()) {
        m_standardOutput << QObject::tr("No data was currently available for reading from port %1").arg(m_serialPort->portName()) << endl;
    } else {
        m_standardOutput << QObject::tr("Data successfully received from port %1").arg(m_serialPort->portName()) << endl;
        m_standardOutput << m_readData << endl;
    }
 
    QCoreApplication::quit();
}
 
void SerialPortReader::handleError(QSerialPort::SerialPortError serialPortError)
{
    if (serialPortError == QSerialPort::ReadError) {
        m_standardOutput << QObject::tr("An I/O error occurred while reading the data from port %1, error: %2").arg(m_serialPort->portName()).arg(m_serialPort->errorString()) << endl;
        QCoreApplication::exit(1);
    }
}

---

So, how can I instantiate QSerialport at constructor?

thx
Zamek

Some advance:

Is it true I need to use connect before I open the port? In terminal example does this.
I tried to this, and in open I get an error: "No such file or direcory". I tried /dev/ttyUSB0 and ttyUSB0 too.

Code:

---

PacketDriver::PacketDriver(const QString& cfgPrefix)
    : mFifo(cfgPrefix)
{
    mSerialPort = new QSerialPort(this);
 
    connect(mSerialPort, SIGNAL(error(QSerialPort::SerialPortError)), this, SLOT(error()));
    connect(mSerialPort, SIGNAL(readyRead()), this, SLOT(onReadyRead()));
 
    mSerialPort->setPortName("/dev/ttyUSB0");
 
    if (!mSerialPort->open(QIODevice::ReadWrite))
        log_exception(PacketDriverException, "cannot open /dev/ttyUSB0");
 
    if (!mSerialPort->setBaudRate(921600))
       log_exception(PacketDriverException, "cannot set baud 921600");
 
    if (!mSerialPort->setDataBits(QSerialPort::Data8))
       log_exception(PacketDriverException, "cannot set databits 8");
 
    if (!mSerialPort->setParity(QSerialPort::NoParity))
       log_exception(PacketDriverException, "cannot set noparity");
 
    if (!mSerialPort->setStopBits(QSerialPort::OneStop))
       log_exception(PacketDriverException, "cannot set one stopbits");
 
    if (!mSerialPort->setFlowControl(QSerialPort::NoFlowControl))
       log_exception(PacketDriverException, "cannot set noflow");
}
 
void PacketDriver::error()
{
    QString err=mSerialPort->errorString();
    std::cout<<"Error:"<<err.toStdString()<<std::endl;
}
 
void PacketDriver::onReadyRead()
{
    std::cout<<"dataAvailable";
    if (mSerialPort->bytesAvailable()) {
        QByteArray bytes = mSerialPort->readAll();
        std::cout<<", bytes:"<<bytes.length()<<std::endl;
        readChar(bytes);
    }
}

---

Could I debug into QtSerial?

thx
Zamek

Seems, you missed setup a port name, like:

Code:

---

SerialPortReader::SerialPortReader(...)
{
...
 
m_serialPort = new QSerialPort();
 
m_serialPort->setPortName("/dev/ttyUSB0"); // << :)
 
if (!m_serialPort->open(QIODevice::ReadWrite))
    return;
...
}

---

UPD:

Quote:

---

Is it true I need to use connect before I open the port? In terminal example does this.

---

Yes, you can... Has no difference do it before or after than open(). But if you do QObject::connect() after open(), don't forget after close() to call QObject::disconnect().

Quote:

---

I tried to this, and in open I get an error: "No such file or direcory". I tried /dev/ttyUSB0 and ttyUSB0 too.

---

It because maybe really a port is not present.

Quote:

---

Could I debug into QtSerial?

---

Yes, of course.

hi,

Quote:

---

Originally Posted by kuzulis

Seems, you missed setup a port name, like:

---

Yes thx, it was a little mistake, I already found it...

Quote:

---

It because maybe really a port is not present.

---

No, the port continuously works, cutecom, gtkterm and qtserialport example terminal can use it and works well. There is a hw, which always sends 80 bytes of frames at every 5 ms.
I used to check with lsof /dev/ttyUSB0 to opened locks. I am the member of dialout groups.

What do I need to set for debugging into source of qtserialport?
When I debug my program, I see the address of serialport, but I can't see the variables and I cannot step into a function.

thx
Zamek

Quote:

---

What do I need to set for debugging into source of qtserialport?

---

Build *.so library as "debug" target... Or directly connect the sources via "serialport-lib.pri" file (imho, *.pri - it is preffered and simple to do gebugging).

Hi Kuzulis,

I found the problem. I wrote this test inside an infinite loop, so the main thread couldn't runs and there was no emitted event on received char.
It was good lesson for me: the main thread cannot blocked!

Many thx to you

Zamek