Qt 串口通信，数据读写

1.串口连接

.pro文件中添加serialPort

QT += core gui serialport //查找可用的串口 foreach (const QSerialPortInfo &info,QSerialPortInfo::availablePorts()) { ui->PortBox->addItem(info.portName()); } QString setPortName = ui->PortBox->currentText(); //端口 int setBaudBox = ui->BaudBox->currentText().toInt(); //波特率 QSerialPort::DataBits setDataBits = ui->BitBox->currentText(); //数据位 QSerialPort::StopBits setStopBits = ui->StopBox->currentText(); //停止位 QSerialPort::Parity setParityBits = ui->ParityBox->currentText(); //校验位 QSerialPort::FlowControl setFlowControl = ui->FlowControl->currentText(); //控制流 //通过读取界面设置的端口数据，选择并设置正确的数据 if(dataBits == "5"){ setDataBits = QSerialPort::Data5; }else if(dataBits == "6"){ setDataBits = QSerialPort::Data6; }else if(dataBits == "7"){ setDataBits = QSerialPort::Data7; }else{ setDataBits = QSerialPort::Data8; } if(stopBits == "1"){ setStopBits = QSerialPort::OneStop; }else if(stopBits == "2"){ setStopBits = QSerialPort::TwoStop; }else{ setStopBits = QSerialPort::OneAndHalfStop; } if(parityBits == "None"){ setParityBits = QSerialPort::NoParity; }else if(parityBits == "Odd"){ setParityBits = QSerialPort::OddParity; }else if(parityBits == "Even"){ setParityBits = QSerialPort::EvenParity; }else if(parityBits == "Mark"){ setParityBits = QSerialPort::MarkParity; }else /*if(parityBits == "Space")*/{ setParityBits = QSerialPort::SpaceParity; } if(flowControl == "HardWare"){ setFlowControl = QSerialPort::HardwareControl; }else if(flowControl == "SoftWare"){ setFlowControl = QSerialPort::SoftwareControl; }else /*if(flowControl == "None")*/{ setFlowControl = QSerialPort::NoFlowControl; } serialPort.setPortName(setPortName); //将设置的串口参数写入 serialPort.setBaudRate(setBaudBox); serialPort.setDataBits(setDataBits); serialPort.setStopBits(setStopBits); serialPort.setParity(setParityBits); serialPort.setFlowControl(setFlowControl); serialPort.open(QIODevice::ReadWrite); //打开串口

2.串口读写数据

//send_byt 位要写入的数据 void mySerialPort::slot_sendText(QByteArray send_byt) { serialPort.write(QByteArray::fromHex(send_byt)); } //读取串口中返回的数据 void mySerialPort::slot_serialPortRead() { QByteArray readText = serialPort.readAll(); emit showRead(readText,button_name); }

这条语句为读取返回数据的关键 作用：当发送数据有效，有返回数据时，会触发slot_serialPortRead()读取返回数据

connect(&serialPort,&QIODevice::readyRead,this,&mySerialPort::slot_serialPortRead); 可以根据自己的需求放在适合的位置，不知道放哪，可以直接放在mySerialPort::mySerialPort(QObject *parent) : QObject(parent){}中； mySerialPort为我当前函数所在

QSerialPort serialPort; connect(&serialPort,&QIODevice::readyRead,this,&mySerialPort::slot_serialPortRead);

在实际工作中，通过串口写入的数据往往是公司给定的协议，我们需要将协议转换为具体的数据，如下图的协议： 根据图中的协议，可以得知我们可能需要发送不同的数据，这就需要我们在图形界面上获取输入的组成协议的数据，再通过协议规则生成完整的数据，并且需要CRC校验。 CRC校验的种类很多，实际工作中根据给定的CRC校验进行校验。

起始码、命令码、功能码、对象索引，有效数据 等根据实际情况输入， 数据长度：第四字节到累计和取反前字节数，[4,n-1] CRC校验：根据给定的校验数据校验 累计和取反：第二字节到累计和取反前一字节，[2,n-1], 计算方式：将每一字节的16进制数相加，满0下0x100从0重新相加，得到累计和，再以0x100 - 累计和。

//*******发送采集数据命令************// void MySerialPort::gatherLog() { QString startCode = "*"; //起始码 QString cmdCode = "A0"; //命令类型码 QString code2 = "0800"; //功能码 static quint16 tmp = 0; //对象索引 QString validData = "aabb"; //有效数据 QByteArray crcData = QByteArray::fromHex(validData.toLatin1()); //将有效数据转换为16进制 quint16 crc = CRC16_Dn_Cal((quint8 *)crcData.data(),(quint32)crcData.length(),(quint16)0xffff); //CRC16校验 crc = ((crc & 0x00FF) << 8) + ((crc & 0xFF00) >> 8); //高低位转换 quint16 index = ((tmp & 0x00FF) << 8) + ((tmp & 0xFF00) >> 8); //偏移的字节 QString needPacketData = code2 + QString("%1").arg(index,4,16,QLatin1Char('0')) + QString::number(crc, 16) + validData; // QString::number(crc, 16) 10进制整数转16进制字符串 QByteArray cheakSumData = data_packet(cmdCode,needPacketData); //得到需要进行校验的数据 QByteArray send_data = cheakSumData + cumulativeSum(cheakSumData); //累计和取反 serialport.write(startCode.toLatin1() + send_data); //串口发送采集命令 tmp++; } /* ------CRC校验函数------ */ quint16 MySerialPort::CRC16_Dn_Cal(quint8 * dat, quint32 len, quint16 startCrc) { const unsigned short CRC16_Dn_ByteTab[ 256 ] = { 0x0000, 0xC0C1, 0xC181, 0x0140, 0xC301, 0x03C0, 0x0280, 0xC241, 0xC601, 0x06C0, 0x0780, 0xC741, 0x0500, 0xC5C1, 0xC481, 0x0440, 0xCC01, 0x0CC0, 0x0D80, 0xCD41, 0x0F00, 0xCFC1, 0xCE81, 0x0E40, 0x0A00, 0xCAC1, 0xCB81, 0x0B40, 0xC901, 0x09C0, 0x0880, 0xC841, 0xD801, 0x18C0, 0x1980, 0xD941, 0x1B00, 0xDBC1, 0xDA81, 0x1A40, 0x1E00, 0xDEC1, 0xDF81, 0x1F40, 0xDD01, 0x1DC0, 0x1C80, 0xDC41, 0x1400, 0xD4C1, 0xD581, 0x1540, 0xD701, 0x17C0, 0x1680, 0xD641, 0xD201, 0x12C0, 0x1380, 0xD341, 0x1100, 0xD1C1, 0xD081, 0x1040, 0xF001, 0x30C0, 0x3180, 0xF141, 0x3300, 0xF3C1, 0xF281, 0x3240, 0x3600, 0xF6C1, 0xF781, 0x3740, 0xF501, 0x35C0, 0x3480, 0xF441, 0x3C00, 0xFCC1, 0xFD81, 0x3D40, 0xFF01, 0x3FC0, 0x3E80, 0xFE41, 0xFA01, 0x3AC0, 0x3B80, 0xFB41, 0x3900, 0xF9C1, 0xF881, 0x3840, 0x2800, 0xE8C1, 0xE981, 0x2940, 0xEB01, 0x2BC0, 0x2A80, 0xEA41, 0xEE01, 0x2EC0, 0x2F80, 0xEF41, 0x2D00, 0xEDC1, 0xEC81, 0x2C40, 0xE401, 0x24C0, 0x2580, 0xE541, 0x2700, 0xE7C1, 0xE681, 0x2640, 0x2200, 0xE2C1, 0xE381, 0x2340, 0xE101, 0x21C0, 0x2080, 0xE041, 0xA001, 0x60C0, 0x6180, 0xA141, 0x6300, 0xA3C1, 0xA281, 0x6240, 0x6600, 0xA6C1, 0xA781, 0x6740, 0xA501, 0x65C0, 0x6480, 0xA441, 0x6C00, 0xACC1, 0xAD81, 0x6D40, 0xAF01, 0x6FC0, 0x6E80, 0xAE41, 0xAA01, 0x6AC0, 0x6B80, 0xAB41, 0x6900, 0xA9C1, 0xA881, 0x6840, 0x7800, 0xB8C1, 0xB981, 0x7940, 0xBB01, 0x7BC0, 0x7A80, 0xBA41, 0xBE01, 0x7EC0, 0x7F80, 0xBF41, 0x7D00, 0xBDC1, 0xBC81, 0x7C40, 0xB401, 0x74C0, 0x7580, 0xB541, 0x7700, 0xB7C1, 0xB681, 0x7640, 0x7200, 0xB2C1, 0xB381, 0x7340, 0xB101, 0x71C0, 0x7080, 0xB041, 0x5000, 0x90C1, 0x9181, 0x5140, 0x9301, 0x53C0, 0x5280, 0x9241, 0x9601, 0x56C0, 0x5780, 0x9741, 0x5500, 0x95C1, 0x9481, 0x5440, 0x9C01, 0x5CC0, 0x5D80, 0x9D41, 0x5F00, 0x9FC1, 0x9E81, 0x5E40, 0x5A00, 0x9AC1, 0x9B81, 0x5B40, 0x9901, 0x59C0, 0x5880, 0x9841, 0x8801, 0x48C0, 0x4980, 0x8941, 0x4B00, 0x8BC1, 0x8A81, 0x4A40, 0x4E00, 0x8EC1, 0x8F81, 0x4F40, 0x8D01, 0x4DC0, 0x4C80, 0x8C41, 0x4400, 0x84C1, 0x8581, 0x4540, 0x8701, 0x47C0, 0x4680, 0x8641, 0x8201, 0x42C0, 0x4380, 0x8341, 0x4100, 0x81C1, 0x8081, 0x4040 }; quint8 temp; quint32 i; quint16 crc = startCrc; for(i = 0; i < len; i ++) { temp=(quint8)(crc & 0x00FF) ^ dat[i]; crc >>= 8; crc ^= CRC16_Dn_ByteTab[temp]; } return crc; } /* --------cheakSum校验函数---------*/ QByteArray MySerialPort::cumulativeSum(QByteArray str) { QByteArray tem = str; quint8 sum = 0; quint16 max = 0x100; for(int i=0;i<tem.length();i++) { sum += tem.at(i); //循环对tem求和 } sum = sum & 0x00FF; sum = max - sum; //得到校验和 return QByteArray::fromHex(QString::number(sum, 16).toLatin1()); } /*---------数据封包函数---------*/ QByteArray MySerialPort::data_packet(QString code,QString str) { QByteArray cmd,after_packet; cmd = QByteArray::fromHex(code.toLatin1()); //获得命令类型码 QString package = str; //n个byte的数据包 int length1 = package.length() / 2; //按2个字符1个byte分，计算出数据长度 QByteArray datalength = QByteArray::fromHex(QByteArray::number(length1,16)); //转换为16进制字符串 QByteArray packet = QByteArray::fromHex(package.toLatin1()); //数据封包 after_packet = cmd + datalength + packet; return after_packet; }