QSerialPort能读多于512字节的数据吗？ [英] Can QSerialPort read more than 512 bytes of data?

问题描述

我想使用QSerialPort读取从设备传输的数据。设备每次发送4000个数据字节的帧。我尝试使用以下简单代码

  QSerialPort * serialPort; 
 char receivedData [4000]; 
 int numRead = 0; 
 
 MainWindow :: MainWindow（QWidget * parent）：
 QMainWindow（parent），
 ui（new Ui :: MainWindow）
 {
 ui- > setupUi（this）; 
 
 / *初始化串口* / 
 serialPort = new QSerialPort（this）; 
 QString portName =COM6; 
 qint32 baudRate = 460800; 
 serialPort-> setPortName（portName）; 
 serialPort-> setBaudRate（baudRate）; 
 serialPort-> setDataBits（QSerialPort :: Data8）; 
 serialPort-> setParity（QSerialPort :: NoParity）; 
 serialPort-> setStopBits（QSerialPort :: OneStop）; 
 serialPort-> setFlowControl（QSerialPort :: NoFlowControl）; 
 serialPort-> setReadBufferSize（4000）; 
 if（！serialPort-> open（QIODevice :: ReadOnly））{
 qDebug（）< 无法打开comport; 
} 
 connect（serialPort，SIGNAL（readyRead（）），this，SLOT（serialReceived（）））; 
} 
 
 void MainWindow :: serialReceived（）
 {
 numRead = serialPort-> read（receivedData，4000）; 
 serialPort-> flush（）; 
} 
  

问题是：它总是显示只读取512个数据字节。如何读取整个4000字节的数据帧？ （当我使用Matlab读取这个4000字节帧，它工作正常）

解决方案

没有限制，不一定接收单个块中的所有数据。
您必须继续侦听，直到有等待的字节数（或超时）。

  void MainWindow :: serialReceived（）
 {
 receivedData.append（serialPort-> readAll（））; 
 if（receivedData.size（）> = 4000）{
 //我们已满
} 
} 
  pre> 
I want to use QSerialPort to read data transmitted from a device. The device transmits a frame of 4000 data bytes each time. I try with the following simple code
QSerialPort *serialPort;
char receivedData[4000];
int numRead = 0;

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    /* Initialize serial port*/
    serialPort = new QSerialPort(this);
    QString portName = "COM6";
    qint32 baudRate = 460800;
    serialPort->setPortName(portName);
    serialPort->setBaudRate(baudRate);
    serialPort->setDataBits(QSerialPort::Data8);
    serialPort->setParity(QSerialPort::NoParity);
    serialPort->setStopBits(QSerialPort::OneStop);
    serialPort->setFlowControl(QSerialPort::NoFlowControl);
    serialPort->setReadBufferSize(4000);
    if (!serialPort->open(QIODevice::ReadOnly)) {
        qDebug() << "Cannot open comport";
    }
    connect(serialPort, SIGNAL(readyRead()), this, SLOT(serialReceived()));
}

void MainWindow::serialReceived()
{
    numRead = serialPort->read(receivedData, 4000);
    serialPort->flush();
}
The problem is: it always shows that only 512 data bytes are read. How can I read the whole 4000 bytes data frame? (when I'm using Matlab to read this 4000 bytes frame, it's working fine)
解决方案
There's no limit, but you don't necessarily receive all data in single chunk.
You have to keep listening until you have the number of bytes you're waiting for (or a timeout).
void MainWindow::serialReceived()
{
    receivedData.append(serialPort->readAll());
    if(receivedData.size() >= 4000) {
       // we're full
    }
}


                        
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