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/****************************************************************************
*
* Copyright (C) 2012 PX4 Development Team. All rights reserved.
*
* 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 controls.c
*
* R/C inputs and servo outputs.
*/
#include <nuttx/config.h>
#include <stdio.h>
#include <stdbool.h>
#include <fcntl.h>
#include <unistd.h>
#include <debug.h>
#include <stdlib.h>
#include <errno.h>
#include <termios.h>
#include <string.h>
#include <poll.h>
#include <nuttx/clock.h>
#include <drivers/drv_hrt.h>
#include <systemlib/hx_stream.h>
#include <systemlib/perf_counter.h>
#include <systemlib/ppm_decode.h>
#define DEBUG
#include "px4io.h"
#define RC_FAILSAFE_TIMEOUT 2000000 /**< two seconds failsafe timeout */
#define RC_CHANNEL_HIGH_THRESH 1700
#define RC_CHANNEL_LOW_THRESH 1300
static void ppm_input(void);
void
controls_main(void)
{
struct pollfd fds[2];
/* DSM input */
fds[0].fd = dsm_init("/dev/ttyS0");
fds[0].events = POLLIN;
/* S.bus input */
fds[1].fd = sbus_init("/dev/ttyS2");
fds[1].events = POLLIN;
for (;;) {
/* run this loop at ~100Hz */
poll(fds, 2, 10);
/*
* Gather R/C control inputs from supported sources.
*
* Note that if you're silly enough to connect more than
* one control input source, they're going to fight each
* other. Don't do that.
*/
bool locked = false;
/*
* Store RC channel count to detect switch to RC loss sooner
* than just by timeout
*/
unsigned rc_channels = system_state.rc_channels;
/*
* Track if any input got an update in this round
*/
bool rc_updated;
if (fds[0].revents & POLLIN)
locked |= dsm_input();
if (fds[1].revents & POLLIN)
locked |= sbus_input(fds[1].fd, PX4IO_INPUT_CHANNELS, &system_state.rc_channel_data,
&system_state.rc_channels, &system_state.rc_channels_timestamp, &rc_updated);
/*
* If we don't have lock from one of the serial receivers,
* look for PPM. It shares an input with S.bus, so there's
* a possibility it will mis-parse an S.bus frame.
*
* XXX each S.bus frame will cause a PPM decoder interrupt
* storm (lots of edges). It might be sensible to actually
* disable the PPM decoder completely if we have an alternate
* receiver lock.
*/
if (!locked)
ppm_input();
/* check for manual override status */
if (system_state.rc_channel_data[4] > RC_CHANNEL_HIGH_THRESH) {
/* force manual input override */
system_state.mixer_manual_override = true;
} else {
/* override not engaged, use FMU */
system_state.mixer_manual_override = false;
}
/*
* If we haven't seen any new control data in 200ms, assume we
* have lost input and tell FMU.
*/
if ((hrt_absolute_time() - system_state.rc_channels_timestamp) > 200000) {
/* set the number of channels to zero - no inputs */
system_state.rc_channels = 0;
rc_updated = true;
}
/*
* If there was a RC update OR the RC signal status (lost / present) has
* just changed, request an update immediately.
*/
system_state.fmu_report_due |= rc_updated;
/*
* PWM output updates are performed in addition on each comm update.
* the updates here are required to ensure operation if FMU is not started
* or stopped responding.
*/
mixer_tick();
}
}
static void
ppm_input(void)
{
/*
* Look for new PPM input.
*/
if (ppm_last_valid_decode != 0) {
/* avoid racing with PPM updates */
irqstate_t state = irqsave();
/* PPM data exists, copy it */
system_state.rc_channels = ppm_decoded_channels;
for (unsigned i = 0; i < ppm_decoded_channels; i++) {
system_state.rc_channel_data[i] = ppm_buffer[i];
}
/* copy the timestamp and clear it */
system_state.rc_channels_timestamp = ppm_last_valid_decode;
ppm_last_valid_decode = 0;
irqrestore(state);
/* trigger an immediate report to the FMU */
system_state.fmu_report_due = true;
}
}
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