通过串口，根据参数名称请求mavlink参数值

一，整体架构

2，代码

void MySerialLink::sendReadPararmeter(QString name)

{

    int componentId = 0;

    int paramIndex=-1;

    int mavlinkSystemID = 255;

    int mavlinkCompontId = 0;

    int vehicleId = 1;

    int channel = 0;

    mavlink_message_t msg;

    char fixedParamName[MAVLINK_MSG_PARAM_REQUEST_READ_FIELD_PARAM_ID_LEN];

    strncpy(fixedParamName, name.toStdString().c_str(), sizeof(fixedParamName));

    mavlink_msg_param_request_read_pack(mavlinkSystemID,    // Our system id

                                        mavlinkCompontId, // Our component id

                                        &msg,                       // Pack into this mavlink_message_t

                                        vehicleId,             // Target system id

                                        componentId,                // Target component id

                                        fixedParamName,             // Named parameter being requested

                                        paramIndex);                // Parameter index being requested, -1 for named

    static const uint8_t messageKeys[256] = MAVLINK_MESSAGE_CRCS;

    mavlink_finalize_message_chan(&msg, mavlinkSystemID, mavlinkCompontId, channel, msg.len, messageKeys[msg.msgid]);

    uint8_t buffer[MAVLINK_MAX_PACKET_LEN];

    int len = mavlink_msg_to_send_buffer(buffer, &msg);

    emit _invokeWriteBytes((const char*)buffer,len);

}

3，

这里没有直接调用串口发送 消息，而是 利用信号与槽  转了一下，否则消息发送失败，原因不详。

connect(this,SIGNAL(_invokeWriteBytes(const char*,qint64)),this,SLOT(sl_sendData(const char*,qint64)));

void MySerialLink::sl_sendData(const char*buff,qint64 size)
{
    if(mPort && mPort->isOpen()) {
        int sendSize =  mPort->write(buff,size);
        qDebug()<<"send data "<<size<<sendSize;
    } else {
        qDebug()<<"Could not send data,mPort is not opened";
    }
}