mavlink协议移植问题

mavlink协议移植问题

mavlink源代码是一个代码库，使用的时候只需要将mavlink.h头文件包含到工程项目中即可。

mavlink通信协议是无状态的连接，一般采用心跳消息跟踪系统是否存在。请确保每60、30、10或1秒发送心跳（建议使用1HZ），一旦心跳到达则视为系统已经连接。

快速整合方法： 发送数据例程（这个例子需要的代码比较多）

/* The default UART header for your MCU */
#include "uart.h"
#include <mavlink/v1./common/mavlink.h>

mavlink_system_t mavlink_system;

mavlink_system.sysid = ;                   ///< ID 20 for this airplane
mavlink_system.compid = MAV_COMP_ID_IMU;     ///< The component sending the message is the IMU, it could be also a Linux process

// Define the system type, in this case an airplane
uint8_t system_type = MAV_TYPE_FIXED_WING;
uint8_t autopilot_type = MAV_AUTOPILOT_GENERIC;

uint8_t system_mode = MAV_MODE_PREFLIGHT; ///< Booting up
uint32_t custom_mode = 0;                 ///< Custom mode, can be defined by user/adopter
uint8_t system_state = MAV_STATE_STANDBY; ///< System ready for flight

// Initialize the required buffers
mavlink_message_t msg;
uint8_t buf[MAVLINK_MAX_PACKET_LEN];

// Pack the message
mavlink_msg_heartbeat_pack(mavlink_system.sysid, mavlink_system.compid, &msg, system_type, autopilot_type, system_mode, custom_mode, system_state);

// Copy the message to the send buffer
uint16_t len = mavlink_msg_to_send_buffer(buf, &msg);

// Send the message with the standard UART send function
// uart0_send might be named differently depending on
// the individual microcontroller / library in use.
uart0_send(buf, len);

接收数据例程：此段代码运行效率比较低，所以建议在主循环中运行该函数，并且尽快清空USART缓冲区。

#include <mavlink/v1./common/mavlink.h>

// Example variable, by declaring them static they're persistent
// and will thus track the system state
static int packet_drops = ;
static int mode = MAV_MODE_UNINIT; /* Defined in mavlink_types.h, which is included by mavlink.h */

/**
* @brief Receive communication packets and handle them
*
* This function decodes packets on the protocol level and also handles
* their value by calling the appropriate functions.
*/
static void communication_receive(void)
{
    mavlink_message_t msg;
    mavlink_status_t status;

    // COMMUNICATION THROUGH EXTERNAL UART PORT (XBee serial)

    while(uart0_char_available())
    {
        uint8_t c = uart0_get_char();
        // Try to get a new message
        if(mavlink_parse_char(MAVLINK_COMM_0, c, &msg, &status)) {
            // Handle message

            switch(msg.msgid)
            {
                    case MAVLINK_MSG_ID_HEARTBEAT:
                    {
                  // E.g. read GCS heartbeat and go into
                                  // comm lost mode if timer times out
                    }
                    break;
            case MAVLINK_MSG_ID_COMMAND_LONG:
                // EXECUTE ACTION
                break;
            default:
                //Do nothing
                break;
            }
        }

        // And get the next one
    }

    // Update global packet drops counter
    packet_drops += status.packet_rx_drop_count;
}

利用适配器函数减少代码

#include "your_mavlink_bridge_header.h"
/* You have to #define MAVLINK_USE_CONVENIENCE_FUNCTIONS in your_mavlink_bridge_header,
   and you have to declare: mavlink_system_t mavlink_system;
   these two variables will be used internally by the mavlink_msg_xx_send() functions.
   Please see the section below for an example of such a bridge header. */
#include <mavlink.h>

// Define the system type, in this case an airplane
int system_type = MAV_FIXED_WING;
// Send a heartbeat over UART0 including the system type
mavlink_msg_heartbeat_send(MAVLINK_COMM_0, system_type, MAV_AUTOPILOT_GENERIC, MAV_MODE_MANUAL_DISARMED, MAV_STATE_STANDBY);

your_mavlink_bridge_header.h
/* MAVLink adapter header */
#ifndef YOUR_MAVLINK_BRIDGE_HEADER_H
#define YOUR_MAVLINK_BRIDGE_HEADER_H

#define MAVLINK_USE_CONVENIENCE_FUNCTIONS

#include <mavlink/v1./mavlink_types.h>

/* Struct that stores the communication settings of this system.
   you can also define / alter these settings elsewhere, as long
   as they're included BEFORE mavlink.h.
   So you can set the

   mavlink_system.sysid = 100; // System ID, 1-255
   mavlink_system.compid = 50; // Component/Subsystem ID, 1-255

   Lines also in your main.c, e.g. by reading these parameter from EEPROM.
 */
mavlink_system_t mavlink_system;
mavlink_system.sysid = ; // System ID, 1-255
mavlink_system.compid = ; // Component/Subsystem ID, 1-255

/**
 * @brief Send one char (uint8_t) over a comm channel
 *
 * @param chan MAVLink channel to use, usually MAVLINK_COMM_0 = UART0
 * @param ch Character to send
 */
static inline void comm_send_ch(mavlink_channel_t chan, uint8_t ch)
{
    if (chan == MAVLINK_COMM_0)
    {
        uart0_transmit(ch);
    }
    if (chan == MAVLINK_COMM_1)
    {
        uart1_transmit(ch);
    }
}

#endif /* YOUR_MAVLINK_BRIDGE_HEADER_H */