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/****************************************************************************
*
* Copyright (C) 2012 PX4 Development Team. All rights reserved.
* Author: @author Example User <mail@example.com>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name PX4 nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/**
* @file px4_simple_app.c
* Minimal application example for PX4 autopilot
*/
#include <nuttx/config.h>
#include <unistd.h>
#include <stdio.h>
#include <poll.h>
#include <string.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[])
{
printf("Hello Sky!\n");
/* subscribe to sensor_combined topic */
int sensor_sub_fd = orb_subscribe(ORB_ID(sensor_combined));
orb_set_interval(sensor_sub_fd, 1000);
/* advertise attitude topic */
struct vehicle_attitude_s att;
memset(&att, 0, sizeof(att));
orb_advert_t att_pub = orb_advertise(ORB_ID(vehicle_attitude), &att);
/* one could wait for multiple topics with this technique, just using one here */
struct pollfd fds[] = {
{ .fd = sensor_sub_fd, .events = POLLIN },
/* there could be more file descriptors here, in the form like:
* { .fd = other_sub_fd, .events = POLLIN },
*/
};
int error_counter = 0;
for (int i = 0; i < 5; i++) {
/* wait for sensor update of 1 file descriptor for 1000 ms (1 second) */
int poll_ret = poll(fds, 1, 1000);
/* handle the poll result */
if (poll_ret == 0) {
/* this means none of our providers is giving us data */
printf("[px4_simple_app] Got no data within a second\n");
} else if (poll_ret < 0) {
/* this is seriously bad - should be an emergency */
if (error_counter < 10 || error_counter % 50 == 0) {
/* use a counter to prevent flooding (and slowing us down) */
printf("[px4_simple_app] ERROR return value from poll(): %d\n"
, poll_ret);
}
error_counter++;
} else {
if (fds[0].revents & POLLIN) {
/* obtained data for the first file descriptor */
struct sensor_combined_s raw;
/* copy sensors raw data into local buffer */
orb_copy(ORB_ID(sensor_combined), sensor_sub_fd, &raw);
printf("[px4_simple_app] Accelerometer:\t%8.4f\t%8.4f\t%8.4f\n",
(double)raw.accelerometer_m_s2[0],
(double)raw.accelerometer_m_s2[1],
(double)raw.accelerometer_m_s2[2]);
/* set att and publish this information for other apps */
att.roll = raw.accelerometer_m_s2[0];
att.pitch = raw.accelerometer_m_s2[1];
att.yaw = raw.accelerometer_m_s2[2];
orb_publish(ORB_ID(vehicle_attitude), att_pub, &att);
}
/* there could be more file descriptors here, in the form like:
* if (fds[1..n].revents & POLLIN) {}
*/
}
}
return 0;
}
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