[SOLVED] QtSerialPort even parity problem on low baudrate

lfxciii

Hi Team

I've been using QtSerialPort, works fine on baudrates 9600 up. I'm trying to use it on 2400 baudrate with evenparity, one stop bit and 7 data bits. but when i use it like this, the parity is out.

is this a common problem which has been fixed? I'm using qt4.8.

thank you for any help

kuzulis

Please provide your code, OS version, QtSerialPort version.

lfxciii

I'm not sure about the QtSerialPort version, but I built it for Qt4, can you tell me how to find the version?

dont have the code with me now, but i'm using this to open the port:
@
if (currentPortNameChanged) {
serial.close();
serial.setPortName(currentPortName);

if (!serial.open(QIODevice::ReadWrite)) {
    emit error(tr("Can't open %1, error code %2")
               .arg(portName).arg(serial.error()));
    return;
}

if (!serial.setBaudRate(QSerialPort::Baud2400)) {
    emit error(tr("Can't set baud rate 2400 baud to port %1, error code %2")
               .arg(portName).arg(serial.error()));
    return;
}

if (!serial.setDataBits(QSerialPort::Data7)) {
    emit error(tr("Can't set 7 data bits to port %1, error code %2")
               .arg(portName).arg(serial.error()));
    return;
}

if (!serial.setParity(QSerialPort::EvenParity)) {
    emit error(tr("Can't set even parity to port %1, error code %2")
               .arg(portName).arg(serial.error()));
    return;
}

if (!serial.setStopBits(QSerialPort::OneStop)) {
    emit error(tr("Can't set 1 stop bit to port %1, error code %2")
               .arg(portName).arg(serial.error()));
    return;
}

if (!serial.setFlowControl(QSerialPort::NoFlowControl)) {
    emit error(tr("Can't set no flow control to port %1, error code %2")
               .arg(portName).arg(serial.error()));
    return;
}

} @

then connect to readyRead
@
connect(&serial, SIGNAL(readyRead(), this, SLOT(readData()), Qt:DirectConnection);

void ClassWhatWhat::readData(){
QByteArray buffer = serial.read(1);
}
@

Then when I view buffer.at(0) equals = 0x82, where in fact, it should be: 0x02

OS version - ubuntu 12.04

thank you for your help

kuzulis

Are you sure that your transmitter send this byte correctly? I mean, are you sure that transmitter also has same 2400,7,E,1,noflow ?

lfxciii

yes i'm sure, i tested it by connecting another laptop to my ubuntu machine. I sent instructions from it to my ubuntu machine and i get the same. it only looks like it happens when reading from the port though.

lfxciii

i also connected the tramitter to the other laptop (not the ubuntu machine),using the same terminal program and the byte comes through correctly

kuzulis

Strange.. But you can create a bug on bug-tracker in any case, or try to understand a problem yourself.

lfxciii

when my transmitter is set to even parity, i get this problem

lfxciii

faulty usb to serial cable.