簡述

Qt下無論是RS232、RS422、RS485的串列埠通訊都可以使用統一的編碼實現。本文把每路串列埠的通訊各放在一個執行緒中，使用movetoThread的方式實現。

程式碼之路

用SerialPort類實現串列埠功能，Widget類呼叫串列埠。
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();  //初始化串列埠
  QSerialPort *port;

public slots:
  void handle_data();  //處理接收到的資料
  void write_data();     //傳送資料

signals:
  //接收資料
  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();  //啟動執行緒

}

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

void SerialPort::init_port()
{
    port->setPortName("/dev/ttyS1");                   //串列埠名 windows下寫作COM1
    port->setBaudRate(38400);                           //波特率
    port->setDataBits(QSerialPort::Data8);             //資料位
    port->setStopBits(QSerialPort::OneStop);           //停止位
    port->setParity(QSerialPort::NoParity);            //奇偶校驗
    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(收到的資料):") << 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);   //傳送“data”字元
}
 

widget.h的呼叫程式碼

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

widget.cpp呼叫程式碼

//建構函式中
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槽函式
void Widget::on_receive(QByteArray tmpdata)
{
 ui->textEdit->append(tmpdata);
}
 

寫在最後

本文例子實現的串列埠號是 /dev/ttyS1（對應windows系統是COM1口），波特率38400，資料位8，停止位1，無校驗位的串列埠通訊。