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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 mixer.cpp
*
* Control channel input/output mixer and failsafe.
*/
#include <nuttx/config.h>
#include <sys/types.h>
#include <stdbool.h>
#include <string.h>
#include <drivers/drv_pwm_output.h>
#include <drivers/drv_hrt.h>
#include <systemlib/mixer/mixer.h>
extern "C" {
//#define DEBUG
#include "px4io.h"
}
/*
* Maximum interval in us before FMU signal is considered lost
*/
#define FMU_INPUT_DROP_LIMIT_US 200000
/* XXX need to move the RC_CHANNEL_FUNCTION out of rc_channels.h and into systemlib */
#define ROLL 0
#define PITCH 1
#define YAW 2
#define THROTTLE 3
#define OVERRIDE 4
/* current servo arm/disarm state */
static bool mixer_servos_armed = false;
/* selected control values and count for mixing */
enum mixer_source {
MIX_NONE,
MIX_FMU,
MIX_OVERRIDE,
MIX_FAILSAFE
};
static mixer_source source;
static int mixer_callback(uintptr_t handle,
uint8_t control_group,
uint8_t control_index,
float &control);
static MixerGroup mixer_group(mixer_callback, 0);
void
mixer_tick(void)
{
/* check that we are receiving fresh data from the FMU */
if (hrt_elapsed_time(&system_state.fmu_data_received_time) > FMU_INPUT_DROP_LIMIT_US) {
/* too long without FMU input, time to go to failsafe */
if (r_status_flags & PX4IO_P_STATUS_FLAGS_FMU_OK) {
debug("AP RX timeout");
}
r_status_flags |= PX4IO_P_STATUS_FLAGS_OVERRIDE;
r_status_flags &= ~(PX4IO_P_STATUS_FLAGS_FMU_OK | PX4IO_P_STATUS_FLAGS_RAW_PWM);
r_status_alarms |= PX4IO_P_STATUS_ALARMS_FMU_LOST;
}
source = MIX_FAILSAFE;
/*
* Decide which set of controls we're using.
*/
if (r_status_flags & PX4IO_P_STATUS_FLAGS_RAW_PWM) {
/* don't actually mix anything - we already have raw PWM values */
source = MIX_NONE;
} else {
if (!(r_status_flags & PX4IO_P_STATUS_FLAGS_OVERRIDE) &&
(r_status_flags & PX4IO_P_STATUS_FLAGS_MIXER_OK)) {
/* mix from FMU controls */
source = MIX_FMU;
}
if ( (r_status_flags & PX4IO_P_STATUS_FLAGS_OVERRIDE) &&
(r_status_flags & PX4IO_P_STATUS_FLAGS_RC_OK)) {
/* if allowed, mix from RC inputs directly */
source = MIX_OVERRIDE;
}
}
/*
* Run the mixers.
*/
if (source == MIX_FAILSAFE) {
/* copy failsafe values to the servo outputs */
for (unsigned i = 0; i < IO_SERVO_COUNT; i++)
r_page_servos[i] = r_page_servo_failsafe[i];
} else if (source != MIX_NONE) {
float outputs[IO_SERVO_COUNT];
unsigned mixed;
/* mix */
mixed = mixer_group.mix(&outputs[0], IO_SERVO_COUNT);
/* scale to PWM and update the servo outputs as required */
for (unsigned i = 0; i < mixed; i++) {
/* save actuator values for FMU readback */
r_page_actuators[i] = FLOAT_TO_REG(outputs[i]);
/* scale to servo output */
r_page_servos[i] = (outputs[i] * 500.0f) + 1500;
}
for (unsigned i = mixed; i < IO_SERVO_COUNT; i++)
r_page_servos[i] = 0;
}
/*
* Decide whether the servos should be armed right now.
*
* We must be armed, and we must have a PWM source; either raw from
* FMU or from the mixer.
*
* XXX correct behaviour for failsafe may require an additional case
* here.
*/
bool should_arm = (/* FMU is armed */ (r_setup_arming & PX4IO_P_SETUP_ARMING_ARM_OK) &&
/* IO is armed */ (r_status_flags & PX4IO_P_STATUS_FLAGS_ARMED) &&
/* there is valid input */ (r_status_flags & (PX4IO_P_STATUS_FLAGS_RAW_PWM | PX4IO_P_STATUS_FLAGS_MIXER_OK)));
if (should_arm && !mixer_servos_armed) {
/* need to arm, but not armed */
up_pwm_servo_arm(true);
mixer_servos_armed = true;
} else if (!should_arm && mixer_servos_armed) {
/* armed but need to disarm */
up_pwm_servo_arm(false);
mixer_servos_armed = false;
}
if (mixer_servos_armed) {
/* update the servo outputs. */
for (unsigned i = 0; i < IO_SERVO_COUNT; i++)
up_pwm_servo_set(i, r_page_servos[i]);
}
}
static int
mixer_callback(uintptr_t handle,
uint8_t control_group,
uint8_t control_index,
float &control)
{
if (control_group != 0)
return -1;
switch (source) {
case MIX_FMU:
if (control_index < PX4IO_CONTROL_CHANNELS) {
control = REG_TO_FLOAT(r_page_controls[control_index]);
break;
}
return -1;
case MIX_OVERRIDE:
if (r_page_rc_input[PX4IO_P_RC_VALID] & (1 << control_index)) {
control = REG_TO_FLOAT(r_page_rc_input[PX4IO_P_RC_BASE + control_index]);
break;
}
return -1;
case MIX_FAILSAFE:
case MIX_NONE:
/* XXX we could allow for configuration of per-output failsafe values */
return -1;
}
return 0;
}
/*
* XXX error handling here should be more aggressive; currently it is
* possible to get STATUS_FLAGS_MIXER_OK set even though the mixer has
* not loaded faithfully.
*/
static char mixer_text[256]; /* large enough for one mixer */
static unsigned mixer_text_length = 0;
void
mixer_handle_text(const void *buffer, size_t length)
{
px4io_mixdata *msg = (px4io_mixdata *)buffer;
isr_debug(2, "mix txt %u", length);
if (length < sizeof(px4io_mixdata))
return;
unsigned text_length = length - sizeof(px4io_mixdata);
switch (msg->action) {
case F2I_MIXER_ACTION_RESET:
isr_debug(2, "reset");
mixer_group.reset();
mixer_text_length = 0;
r_status_flags &= ~PX4IO_P_STATUS_FLAGS_MIXER_OK;
/* FALLTHROUGH */
case F2I_MIXER_ACTION_APPEND:
isr_debug(2, "append %d", length);
/* check for overflow - this is really fatal */
/* XXX could add just what will fit & try to parse, then repeat... */
if ((mixer_text_length + text_length + 1) > sizeof(mixer_text)) {
r_status_flags &= ~PX4IO_P_STATUS_FLAGS_MIXER_OK;
return;
}
/* append mixer text and nul-terminate */
memcpy(&mixer_text[mixer_text_length], msg->text, text_length);
mixer_text_length += text_length;
mixer_text[mixer_text_length] = '\0';
isr_debug(2, "buflen %u", mixer_text_length);
/* process the text buffer, adding new mixers as their descriptions can be parsed */
unsigned resid = mixer_text_length;
mixer_group.load_from_buf(&mixer_text[0], resid);
/* if anything was parsed */
if (resid != mixer_text_length) {
/* ideally, this should test resid == 0 ? */
r_status_flags |= PX4IO_P_STATUS_FLAGS_MIXER_OK;
isr_debug(2, "used %u", mixer_text_length - resid);
/* copy any leftover text to the base of the buffer for re-use */
if (resid > 0)
memcpy(&mixer_text[0], &mixer_text[mixer_text_length - resid], resid);
mixer_text_length = resid;
}
break;
}
}
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