Qt下实现多线程的串口通信

简述

Qt下无论是RS232、RS422、RS485的串口通信都可以使用统一的编码实现。本文把每路串口的通信各放在一个线程中，使用movetoThread的方式实现。

代码之路

用SerialPort类实现串口功能，Widget类调用串口。
serialport.h如下

#include <QObject>
#include <QSerialPort>
#include <QString>
#include <QByteArray>
#include <QObject>
#include <QDebug>
#include <QObject>
#include <QThread>

class SerialPort : public QObject
{
  Q_OBJECT
public:
  explicit SerialPort(QObject *parent = NULL);
  ~SerialPort();

  void init_port();  //初始化串口
  QSerialPort *port;

public slots:
  void handle_data();  //处理接收到的数据
  void write_data();     //发送数据

signals:
  //接收数据
  void receive_data(QByteArray tmp);

private:
  QThread *my_thread;
};

serailport.cpp如下

#include "serialport.h"

SerialPort::SerialPort(QObject *parent) : QObject(parent)
{
    my_thread = new QThread();

    port = new QSerialPort();
    init_port();
    this->moveToThread(my_thread);
    port->moveToThread(my_thread);
    my_thread->start();  //启动线程

}

SerialPort::~SerialPort()
{
    port->close();
    port->deleteLater();
    my_thread->quit();
    my_thread->wait();
    my_thread->deleteLater();
}

void SerialPort::init_port()
{
    port->setPortName("/dev/ttyS1");                   //串口名 windows下写作COM1
    port->setBaudRate(38400);                           //波特率
    port->setDataBits(QSerialPort::Data8);             //数据位
    port->setStopBits(QSerialPort::OneStop);           //停止位
    port->setParity(QSerialPort::NoParity);            //奇偶校验
    port->setFlowControl(QSerialPort::NoFlowControl);  //流控制
    if (port->open(QIODevice::ReadWrite))
    {
        qDebug() << "Port have been opened";
    }
    else
    {
        qDebug() << "open it failed";
    }
    connect(port, SIGNAL(readyRead()), this, SLOT(handle_data()), Qt::QueuedConnection); //Qt::DirectConnection
}

void SerialPort::handle_data()
{
    QByteArray data = port->readAll();
    qDebug() << QStringLiteral("data received(收到的数据):") << data;
    qDebug() << "handing thread is:" << QThread::currentThreadId();
    emit receive_data(data);
}

void SerialPort::write_data()
{
    qDebug() << "write_id is:" << QThread::currentThreadId();
    port->write("data", 4);   //发送“data”字符
}

widget.h的调用代码

#include "serialport.h"
public slots:
  void on_receive(QByteArray tmpdata);
private:
  SerialPort *local_serial;

widget.cpp调用代码

//构造函数中
local_serial = new QSerialPort();
connect(ui->pushButton, SIGNAL(clicked()), local_serial, SLOT(write_data()));
connect(local_serial, SIGNAL(receive_data(QByteArray)), this, SLOT(on_receive(QByteArray)), Qt::QueuedConnection);
//on_receive槽函数
void Widget::on_receive(QByteArray tmpdata)
{
 ui->textEdit->append(tmpdata);
}

写在最后

本文例子实现的串口号是 /dev/ttyS1（对应windows系统是COM1口），波特率38400，数据位8，停止位1，无校验位的串口通信。