Use the readyRead() signal to get notified when new data is available in the device instead of looping forever. You need to call readAll only when you know that new data has arrived. Currently, You are just calling readAll in an endless loop (this makes the thread, spend all its time in this loop, unable to receive the new data that may have arrived.) Instead, it returns currently available data (data that can be read from the device without waiting). This means that readAll() does not wait for data to arrive. Most IO functions in Qt are asynchronous. this is called when a serial communication error occurs Here is my final code QSerialPort serial Thanks to mike i can finaly read this usb device !!! If no why there is no data display via the qDebug().Did i miss something in the setting of the QSerialPort ?.If(!tBaudRate(QSerialPort::Baud1200, QSerialPort::Input)) Now i want to read the data via a Qt5.3 program QSerialPort serial sudo stty -F /dev/ttyUSB0 1200 sane parenb evenp cs7 -crtsctsĪnd the data are like this TGPHI_s -0,24 =.(Thread modified from QSerialPort BlockingMaster example.I am trying to read the data sent by a device plug via usb. If device is desired type ('Light'), then we format the device ID to the intended QByteArray message structure. QObject::connect(&thread, SIGNAL(timeout(QString)),įunction used to iterate through QList of devices. QObject::connect(&thread, SIGNAL(error(QString)), Setup signal-slot connections: QObject::connect(&thread, SIGNAL(sendResponse(QByteArray)), I have tried many different examples and configurations, currently I am using the following: Now, my problem – I must not have my function setup properly to send and then receive the response bytes. If off, the modem would send back 0x00 in the last byte position if the device was off. The returned message indicates exactly what I would expect, that the device is on. Using Docklight, I receive the response: 02 62 1D E9 4B 05 19 00 06 02 50 20 CB CF 1E DA F7 21 00 FF I send the following message to query the state of the device: 02 62 1D E9 4B 05 19 00 I have tested my message using DockLight ( ). When I send messages to my INSTEON modem (serial), upon reading my message the device sends back a copy of my message + 0x06 (ACK Byte) followed by a status message. I am using the QSerialPort ( ) module to instantiate device IO support. I am sending (writing) bytes to a device via my serial port.

Qt serial port read