PX4应用实例3：px4_simple_app

1. 打开src/examples/px4_simple_app/px4_simple_app.c

#include <px4_config.h>
#include <px4_tasks.h>
#include <px4_posix.h>
#include <unistd.h>
#include <stdio.h>
#include <poll.h>
#include <string.h>
#include <math.h>

#include <uORB/uORB.h>
#include <uORB/topics/sensor_combined.h>
#include <uORB/topics/vehicle_attitude.h>

__EXPORT int px4_simple_app_main(int argc, char *argv[]);

int px4_simple_app_main(int argc, char *argv[])
{
PX4_INFO("Hello Sky!");

/* 订阅 sensor_combined主题*/
int sensor_sub_fd = orb_subscribe(ORB_ID(sensor_combined));
orb_set_interval(sensor_sub_fd, 200);//限制更新频率为5 Hz

/* 1.公告attitude主题 */
struct vehicle_attitude_s att;
memset(&att, 0, sizeof(att));
orb_advert_t att_pub = orb_advertise(ORB_ID(vehicle_attitude), &att);

/* 可以在此等待多个主题 */
px4_pollfd_struct_t fds[] =
{
{ .fd = sensor_sub_fd, .events = POLLIN },
};

int error_counter = 0;

for (int i = 0; i < 5; i++)
{
/* 等待1000ms获取数据 */
int poll_ret = px4_poll(fds, 1, 1000);

/* 处理结果*/
if (poll_ret == 0) //未得到数据
{
PX4_ERR("Got no data within a second");
}
else if (poll_ret < 0) //严重错误
{
if (error_counter < 10 || error_counter % 50 == 0)
{
/* use a counter to prevent flooding (and slowing us down) */
PX4_ERR("ERROR return value from poll(): %d", poll_ret);
}
error_counter++;
}
else //抓到数据
{
if (fds[0].revents & POLLIN)
{
/* 复制sensor_combined公告主题 */
struct sensor_combined_s raw;
orb_copy(ORB_ID(sensor_combined), sensor_sub_fd, &raw);

PX4_INFO("Accelerometer:\t%8.4f\t%8.4f\t%8.4f",
(double)raw.accelerometer_m_s2[0],
(double)raw.accelerometer_m_s2[1],
(double)raw.accelerometer_m_s2[2]);

/* q在.msg中定义*/
att.q[0] = raw.accelerometer_m_s2[0];
att.q[1] = raw.accelerometer_m_s2[1];
att.q[2] = raw.accelerometer_m_s2[2];
/*2. 发布attitude主题*/
orb_publish(ORB_ID(vehicle_attitude), att_pub, &att);
}
/* if (fds[1..n].revents & POLLIN) {} */
}
}

PX4_INFO("exiting");

return 0;
}

2. 修改Firmware\cmake\configs\nuttx_px4fmu-v2_default.cmake文件

将# examples/px4_simple_app中的#删除

3.运行teraterm