浅谈APM系列----void Copter::setup()和void Copter::loop()

APM与PX4底层之间的关系

PX4创建任务之后，调用APM中的void Copter::setup()和void Copter::loop()函数

位置：X:\ardupilot\libraries\AP_HAL_PX4\HAL_PX4_Class.cpp

在HAL_PX4_Class.cpp文件中，有如下代码

static AP_HAL::HAL::Callbacks* g_callbacks;

void HAL_PX4::run(int argc, char * const argv[], Callbacks* callbacks)

 g_callbacks = callbacks;

在main_loop中调用了

g_callbacks->setup();

g_callbacks->loop();

我们应该还记得APM中的

AP_HAL_MAIN_CALLBACKS(&copter);

和

#pragma once

#include "HAL.h"

#if CONFIG_HAL_BOARD == HAL_BOARD_PX4 || CONFIG_HAL_BOARD == HAL_BOARD_VRBRAIN
#define AP_MAIN __EXPORT ArduPilot_main
#endif

#ifndef AP_MAIN
#define AP_MAIN main
#endif

#define AP_HAL_MAIN() \
    AP_HAL::HAL::FunCallbacks callbacks(setup, loop); \
    extern "C" {                               \
    int AP_MAIN(int argc, char* const argv[]); \
    int AP_MAIN(int argc, char* const argv[]) { \
        hal.run(argc, argv, &callbacks); \
        return 0; \
    } \
    }

#define AP_HAL_MAIN_CALLBACKS(CALLBACKS) extern "C" { \
    int AP_MAIN(int argc, char* const argv[]); \
    int AP_MAIN(int argc, char* const argv[]) { \
        hal.run(argc, argv, CALLBACKS); \
        return 0; \
    } \
    }

其中的copter，是一个Copter的对象

Copter copter;

看到这里你应该明白了，APM中的set函数和loop函数是怎么被调用的了

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APM中的void Copter::setup()函数，由PX4调用

位置：X:\ardupilot\ArduCopter\ArduCopter.cpp

void Copter::setup()
{
    // Load the default values of variables listed in var_info[]s
    AP_Param::setup_sketch_defaults();

    // setup storage layout for copter
    StorageManager::set_layout_copter();

    init_ardupilot();

    // initialise the main loop scheduler
    scheduler.init(&scheduler_tasks[0], ARRAY_SIZE(scheduler_tasks));

    // setup initial performance counters
    perf_info.reset(scheduler.get_loop_rate_hz());
    fast_loopTimer = AP_HAL::micros();
}

APM中的void Copter::loop()函数，同样是由PX4调用

位置：X:\ardupilot\ArduCopter\ArduCopter.cpp

void Copter::loop()
{
    // wait for an INS sample
    ins.wait_for_sample();//等待最新的传感器数据

    uint32_t timer = micros();

    // check loop time
    perf_info.check_loop_time(timer - fast_loopTimer);

    // used by PI Loops
    G_Dt                    = (float)(timer - fast_loopTimer) / 1000000.0f;//计算Dt,用于PID计算
    fast_loopTimer          = timer;

    // for mainloop failure monitoring
    mainLoop_count++;

    // Execute the fast loop
    // ---------------------
    fast_loop();

    // tell the scheduler one tick has passed
    scheduler.tick();

    // run all the tasks that are due to run. Note that we only
    // have to call this once per loop, as the tasks are scheduled
    // in multiples of the main loop tick. So if they don't run on
    // the first call to the scheduler they won't run on a later
    // call until scheduler.tick() is called again
    const uint32_t loop_us = scheduler.get_loop_period_us();
    const uint32_t time_available = (timer + loop_us) - micros();
    scheduler.run(time_available > loop_us ? 0u : time_available);
}

明日复明日，明日何其多

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后面将继续更新，APM的其他部分代码。希望能对你的学习和工作有所帮助。

请耐心等待。。。。。