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px4-firmware/apps/px4io/controls.c

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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 <stdbool.h>
#include <drivers/drv_hrt.h>
#include <systemlib/perf_counter.h>
#include <systemlib/ppm_decode.h>
#include "px4io.h"
#define RC_FAILSAFE_TIMEOUT 2000000 /**< two seconds failsafe timeout */
#define RC_CHANNEL_HIGH_THRESH 5000
#define RC_CHANNEL_LOW_THRESH -5000
static bool ppm_input(uint16_t *values, uint16_t *num_values);
static perf_counter_t c_gather_dsm;
static perf_counter_t c_gather_sbus;
static perf_counter_t c_gather_ppm;
void
controls_init(void)
{
/* DSM input */
dsm_init("/dev/ttyS0");
/* S.bus input */
sbus_init("/dev/ttyS2");
/* default to a 1:1 input map, all enabled */
for (unsigned i = 0; i < MAX_CONTROL_CHANNELS; i++) {
unsigned base = PX4IO_P_RC_CONFIG_STRIDE * i;
r_page_rc_input_config[base + PX4IO_P_RC_CONFIG_OPTIONS] = 0;
r_page_rc_input_config[base + PX4IO_P_RC_CONFIG_MIN] = 1000;
r_page_rc_input_config[base + PX4IO_P_RC_CONFIG_CENTER] = 1500;
r_page_rc_input_config[base + PX4IO_P_RC_CONFIG_MAX] = 2000;
r_page_rc_input_config[base + PX4IO_P_RC_CONFIG_DEADZONE] = 30;
r_page_rc_input_config[base + PX4IO_P_RC_CONFIG_ASSIGNMENT] = i;
r_page_rc_input_config[base + PX4IO_P_RC_CONFIG_OPTIONS] = PX4IO_P_RC_CONFIG_OPTIONS_ENABLED;
}
c_gather_dsm = perf_alloc(PC_ELAPSED, "c_gather_dsm");
c_gather_sbus = perf_alloc(PC_ELAPSED, "c_gather_sbus");
c_gather_ppm = perf_alloc(PC_ELAPSED, "c_gather_ppm");
}
void
controls_tick() {
/*
* 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.
*/
perf_begin(c_gather_dsm);
bool dsm_updated = dsm_input(r_raw_rc_values, &r_raw_rc_count);
if (dsm_updated)
r_status_flags |= PX4IO_P_STATUS_FLAGS_RC_DSM;
perf_end(c_gather_dsm);
perf_begin(c_gather_sbus);
bool sbus_updated = sbus_input(r_raw_rc_values, &r_raw_rc_count);
if (sbus_updated)
r_status_flags |= PX4IO_P_STATUS_FLAGS_RC_SBUS;
perf_end(c_gather_sbus);
/*
* 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 S.bus signal.
*/
perf_begin(c_gather_ppm);
bool ppm_updated = ppm_input(r_raw_rc_values, &r_raw_rc_count);
if (ppm_updated)
r_status_flags |= PX4IO_P_STATUS_FLAGS_RC_PPM;
perf_end(c_gather_ppm);
ASSERT(r_raw_rc_count <= MAX_CONTROL_CHANNELS);
/*
* In some cases we may have received a frame, but input has still
* been lost.
*/
bool rc_input_lost = false;
/*
* If we received a new frame from any of the RC sources, process it.
*/
if (dsm_updated || sbus_updated || ppm_updated) {
/* update RC-received timestamp */
system_state.rc_channels_timestamp = hrt_absolute_time();
/* record a bitmask of channels assigned */
unsigned assigned_channels = 0;
/* map raw inputs to mapped inputs */
/* XXX mapping should be atomic relative to protocol */
for (unsigned i = 0; i < r_raw_rc_count; i++) {
/* map the input channel */
uint16_t *conf = &r_page_rc_input_config[i * PX4IO_P_RC_CONFIG_STRIDE];
if (conf[PX4IO_P_RC_CONFIG_OPTIONS] & PX4IO_P_RC_CONFIG_OPTIONS_ENABLED) {
uint16_t raw = r_raw_rc_values[i];
int16_t scaled;
/*
* 1) Constrain to min/max values, as later processing depends on bounds.
*/
if (raw < conf[PX4IO_P_RC_CONFIG_MIN])
raw = conf[PX4IO_P_RC_CONFIG_MIN];
if (raw > conf[PX4IO_P_RC_CONFIG_MAX])
raw = conf[PX4IO_P_RC_CONFIG_MAX];
/*
* 2) Scale around the mid point differently for lower and upper range.
*
* This is necessary as they don't share the same endpoints and slope.
*
* First normalize to 0..1 range with correct sign (below or above center),
* then scale to 20000 range (if center is an actual center, -10000..10000,
* if parameters only support half range, scale to 10000 range, e.g. if
* center == min 0..10000, if center == max -10000..0).
*
* As the min and max bounds were enforced in step 1), division by zero
* cannot occur, as for the case of center == min or center == max the if
* statement is mutually exclusive with the arithmetic NaN case.
*
* DO NOT REMOVE OR ALTER STEP 1!
*/
if (raw > (conf[PX4IO_P_RC_CONFIG_CENTER] + conf[PX4IO_P_RC_CONFIG_DEADZONE])) {
scaled = 10000.0f * ((raw - conf[PX4IO_P_RC_CONFIG_CENTER] - conf[PX4IO_P_RC_CONFIG_DEADZONE]) / (float)(conf[PX4IO_P_RC_CONFIG_MAX] - conf[PX4IO_P_RC_CONFIG_CENTER] - conf[PX4IO_P_RC_CONFIG_DEADZONE]));
} else if (raw < (conf[PX4IO_P_RC_CONFIG_CENTER] - conf[PX4IO_P_RC_CONFIG_DEADZONE])) {
scaled = 10000.0f * ((raw - conf[PX4IO_P_RC_CONFIG_CENTER] - conf[PX4IO_P_RC_CONFIG_DEADZONE]) / (float)(conf[PX4IO_P_RC_CONFIG_CENTER] - conf[PX4IO_P_RC_CONFIG_DEADZONE] - conf[PX4IO_P_RC_CONFIG_MIN]));
} else {
/* in the configured dead zone, output zero */
scaled = 0;
}
/* invert channel if requested */
if (conf[PX4IO_P_RC_CONFIG_OPTIONS] & PX4IO_P_RC_CONFIG_OPTIONS_REVERSE)
scaled = -scaled;
/* and update the scaled/mapped version */
unsigned mapped = conf[PX4IO_P_RC_CONFIG_ASSIGNMENT];
ASSERT(mapped < MAX_CONTROL_CHANNELS);
r_rc_values[mapped] = SIGNED_TO_REG(scaled);
assigned_channels |= (1 << mapped);
}
}
/* set un-assigned controls to zero */
for (unsigned i = 0; i < MAX_CONTROL_CHANNELS; i++) {
if (!(assigned_channels & (1 << i)))
r_rc_values[i] = 0;
}
/*
* If we got an update with zero channels, treat it as
* a loss of input.
*
* This might happen if a protocol-based receiver returns an update
* that contains no channels that we have mapped.
*/
if (assigned_channels == 0) {
rc_input_lost = true;
} else {
/* set RC OK flag and clear RC lost alarm */
r_status_flags |= PX4IO_P_STATUS_FLAGS_RC_OK;
r_status_alarms &= ~PX4IO_P_STATUS_ALARMS_RC_LOST;
}
/*
* Export the valid channel bitmap
*/
r_rc_valid = assigned_channels;
}
/*
* If we haven't seen any new control data in 200ms, assume we
* have lost input.
*/
if (hrt_elapsed_time(&system_state.rc_channels_timestamp) > 200000) {
rc_input_lost = true;
/* clear the input-kind flags here */
r_status_flags &= ~(
PX4IO_P_STATUS_FLAGS_RC_PPM |
PX4IO_P_STATUS_FLAGS_RC_DSM |
PX4IO_P_STATUS_FLAGS_RC_SBUS);
}
/*
* Handle losing RC input
*/
if (rc_input_lost) {
/* Clear the RC input status flag, clear manual override flag */
r_status_flags &= ~(
PX4IO_P_STATUS_FLAGS_OVERRIDE |
PX4IO_P_STATUS_FLAGS_RC_OK);
/* Set the RC_LOST alarm */
r_status_alarms |= PX4IO_P_STATUS_ALARMS_RC_LOST;
/* Mark the arrays as empty */
r_raw_rc_count = 0;
r_rc_valid = 0;
}
/*
* Check for manual override.
*
* The PX4IO_P_SETUP_ARMING_MANUAL_OVERRIDE_OK flag must be set, and we
* must have R/C input.
* Override is enabled if either the hardcoded channel / value combination
* is selected, or the AP has requested it.
*/
if ((r_setup_arming & PX4IO_P_SETUP_ARMING_MANUAL_OVERRIDE_OK) &&
(r_status_flags & PX4IO_P_STATUS_FLAGS_RC_OK)) {
bool override = false;
/*
* Check mapped channel 5 (can be any remote channel,
* depends on RC_MAP_OVER parameter);
* If the value is 'high' then the pilot has
* requested override.
*
*/
if ((r_status_flags & PX4IO_P_STATUS_FLAGS_RC_OK) && (REG_TO_SIGNED(r_rc_values[4]) > RC_CHANNEL_HIGH_THRESH))
override = true;
if (override) {
r_status_flags |= PX4IO_P_STATUS_FLAGS_OVERRIDE;
/* mix new RC input control values to servos */
if (dsm_updated || sbus_updated || ppm_updated)
mixer_tick();
} else {
r_status_flags &= ~PX4IO_P_STATUS_FLAGS_OVERRIDE;
}
}
}
static bool
ppm_input(uint16_t *values, uint16_t *num_values)
{
bool result = false;
/* avoid racing with PPM updates */
irqstate_t state = irqsave();
/*
* If we have received a new PPM frame within the last 200ms, accept it
* and then invalidate it.
*/
if (hrt_elapsed_time(&ppm_last_valid_decode) < 200000) {
/* PPM data exists, copy it */
*num_values = ppm_decoded_channels;
if (*num_values > MAX_CONTROL_CHANNELS)
*num_values = MAX_CONTROL_CHANNELS;
for (unsigned i = 0; i < *num_values; i++)
values[i] = ppm_buffer[i];
/* clear validity */
ppm_last_valid_decode = 0;
/* good if we got any channels */
result = (*num_values > 0);
}
irqrestore(state);
return result;
}
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