10/16/2021 0 Comments Qt Serial Port Example
It provides information on the available serial ports on the system. To do this I use the qextserialport library (version 1.2alpha).Qt serial communication basics and terminologyQSerialPortInfo is a helper class. So we have to install a library to be able to communicate with the port com. Even if Qt is very huge and provides a lot of tools, there is one thing which is missing in our case : the serial port functions. Step 2: Installation of the Library.I dont recommend doing it like this. In some cases you can do it like this, but its blocking, meaning that your GUI will freeze while your app is waiting for the serial port. To run the example from Qt Creator, open the Welcome mode and select the example from Examples.PyFirmata is basically a prebuilt library package of python program which can be installed in Arduino to allow serial communication between a python script.The concept of serial communications is very simple,The serial port sends and receives bytes in bits.Although slower than parallel communication by byte,However, the serial port can use one wire to send data while receiving data on the other wire.It is simple and enables long-distance communication.For example, when ieee488 defines a parallel traffic state,It is stipulated that the total length of equipment lines shall not exceed 20 meters, and the length between any two equipments shall not exceed 2 meters Open the port The bad way. For getting information about the available ports, use the static method availablePorts(). This GUI example displays information about serial ports in a widget, provided by the class QSerialPortInfo.The baud rates of telephone lines are usually 14400, 28800, and 36600. Generally the modulation rate is greater than the baud rate,Such as Manchester coding). Therefore, registering a service with custom values for these fields might not yield the expected result on Windows.This is a parameter that measures the symbol transmission rate.Refers to the change in the unit time after the signal is modulated,That is, the number of times the carrier parameter changes in a unit time,For example, 240 characters are transmitted per second, and each character format contains 10 bits (1 start bit,1 stop bit,8 data bits), the baud rate at this time is 240bd, and the bit rate is 10 bits * 240 bits/second=2400bps.If the data uses simple text (standard ascii code), then each packet uses 7 bits of data. The extended ascii code is 0 to 255 (8 bits). How you set it up depends on the message i want to send.For example, the standard ascii code is 0 to 127 (7 bits). The standard values are 6, 7 and 8 bits. Data bits:This is a parameter that measures the actual data bits in the communication.When the computer sends a packet,The actual data is often not 8 bits.
Qt Serial Port Example Install A LibraryParity bit:A simple error detection method in serial communication.There are four error detection modes:even, odd, high, and low. Since the data is timed on the transmission line,And each device has its own clock,It is possible that a small out-of-sync occurred between the two devices during communication.So the stop bit is more than just the end of the transfer,It also provides the computer with the opportunity to correct the clock synchronization.The more bits that apply to the stop bit,The greater the tolerance of different clock synchronization,But the data transfer rate is also slower. Stop bits:Used to represent the last bit of a single packet.Typical values are 1, 1.5 and 2 digits. Download paint for mac os xQt serial communication module qserialport class member functions //ConstructorQserialport ::qserialport (qobject * parent=q_nullptr)Qserialport ::qserialport (const qstring&name, qobject * parent=q_nullptr)Qserialport ::qserialport (const qserialportinfo&serialportinfo, qobject * parent=q_nullptr)//If no data is currently readable,Returns true bool qserialport ::atend () const//After the baud rate changes,Signal trigger void qserialport ::baudratechanged (qint32 baudrate, qserialport ::directions directions)//Returns the number of bytes of readable data qint64 qserialport ::bytesavailable () const//Return the number of bytes of writable data qint64 qserialport ::bytestowrite () const//Set the serial port information to serialportinfoVoid qserialport ::setport (const qserialportinfo&serialportinfo)Void qserialport ::setportname (const qstring&name)Qt serial communication module qserialport simple serial port exampleThe mainwindows.h code reference is as follows: #ifndef mainwindow_hExplicit mainwindow (qwidget * parent=0) Mainwindows.cpp code #include "mainwindow.h"Static const char blankstring =qt_translate_noop ("settingsdialog", "n/a") Mainwindow ::mainwindow (qwidget * parent):Qmainwindow (parent), ui (new ui ::mainwindow)Qlistserialportinfos=qserialportinfo ::availableports () //Output the number of serial ports that the current system can useQdebug ()combobox_serialport->additem (list. Pro file:Qserialport provides interface functions to access the serial port.Use the auxiliary class qserialportinfo to get the available serial port information.Take the qserialportinfo helper object as a parameter,Use the setport () or setportname () function to set the serial device to be accessed.After setting the port,You can use the open () function to open it in read-only, write-only, or read-write mode.Note that the serial port is opened exclusively.Use the close () function to close the serial port and cancel the io operation.After the serial port is successfully opened,qserialport will try to determine the current configuration of the serial port and initialize it.You can use the setbaudrate (), setdatabits (), setparity (), setstopbits (), and setflowcontrol () functions to reconfigure port settings.There are a pair of attributes named qserialport ::dataterminalready, qserialport ::requesttosendQserialport provides a series of functions that terminate the calling thread until the signal is triggered.These functions are used to block the serial port.Waitforreadyread ():blocking call,Until new data is readableWaitforbyteswritten ():blocking call,Until the data and write to the serial portBlocking serial programming is completely different from non-blocking serial programming.Blocking the serial port does not require a time loop and usually simplifies the code.However, in the gui program, to avoid freezing the user interface,Blocked serial programming can only be used for non-gui threads.Qserialport can also use the stream operators of qtextstream and qdatastream.When trying to read using the stream operator> , you need to make sure that there is enough data available. Timeout and delay configuration for read or write operationsTo use qtserialport in your application, you need to include the following declaration:To link the qtserialport module, you need to add the following to the. Introduction to qt serial communication module qtserialportThe qtserialport module is a module of the additional module in qt5,Provides a unified interface for hardware and virtual serial ports.Because of its simplicity and reliability, the serial portIt is still widely used in industries such as embedded systems and robots.Using the qtserialport module, developers can greatly shorten the development cycle of serial port-related applications.Qt serialport provides basic functions,Including configuration, i/o operation, obtaining and setting the signal of rs-232 pin.The qt serialport module does not currently support the following features:A, terminal characteristics,For example,Control cr/lf, etc.C.
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