LibrePilot/flight/modules/Actuator/actuator.c

/**
 ******************************************************************************
 * @addtogroup OpenPilotModules OpenPilot Modules
 * @{
 * @addtogroup ActuatorModule Actuator Module
 * @brief Compute servo/motor settings based on @ref ActuatorDesired "desired actuator positions" and aircraft type.
 * This is where all the mixing of channels is computed.
 * @{
 *
 * @file       actuator.c
 * @author     The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
 * @brief      Actuator module. Drives the actuators (servos, motors etc).
 *
 * @see        The GNU Public License (GPL) Version 3
 *
 *****************************************************************************/
/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
 * for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */


#include <openpilot.h>

#include "accessorydesired.h"
#include "actuator.h"
#include "actuatorsettings.h"
#include "systemsettings.h"
#include "actuatordesired.h"
#include "actuatorcommand.h"
#include "flightstatus.h"
#include "mixersettings.h"
#include "mixerstatus.h"
#include "cameradesired.h"
#include "manualcontrolcommand.h"
#include "taskinfo.h"

// Private constants
#define MAX_QUEUE_SIZE 2

#if defined(PIOS_ACTUATOR_STACK_SIZE)
#define STACK_SIZE_BYTES PIOS_ACTUATOR_STACK_SIZE
#else
#define STACK_SIZE_BYTES 1312
#endif

#define TASK_PRIORITY (tskIDLE_PRIORITY+4)
#define FAILSAFE_TIMEOUT_MS 100
#define MAX_MIX_ACTUATORS ACTUATORCOMMAND_CHANNEL_NUMELEM

#define CAMERA_BOOT_DELAY_MS	7000

// Private types


// Private variables
static xQueueHandle queue;
static xTaskHandle taskHandle;

static float lastResult[MAX_MIX_ACTUATORS]={0,0,0,0,0,0,0,0};
static float filterAccumulator[MAX_MIX_ACTUATORS]={0,0,0,0,0,0,0,0};
// used to inform the actuator thread that actuator update rate is changed
static volatile bool actuator_settings_updated;
// used to inform the actuator thread that mixer settings are changed
static volatile bool mixer_settings_updated;

// Private functions
static void actuatorTask(void* parameters);
static int16_t scaleChannel(float value, int16_t max, int16_t min, int16_t neutral);
static void setFailsafe(const ActuatorSettingsData * actuatorSettings, const MixerSettingsData * mixerSettings);
static float MixerCurve(const float throttle, const float* curve, uint8_t elements);
static bool set_channel(uint8_t mixer_channel, uint16_t value, const ActuatorSettingsData * actuatorSettings);
static void actuator_update_rate_if_changed(const ActuatorSettingsData * actuatorSettings, bool force_update);
static void MixerSettingsUpdatedCb(UAVObjEvent * ev);
static void ActuatorSettingsUpdatedCb(UAVObjEvent * ev);
float ProcessMixer(const int index, const float curve1, const float curve2,
		   const MixerSettingsData* mixerSettings, ActuatorDesiredData* desired,
		   const float period);

//this structure is equivalent to the UAVObjects for one mixer.
typedef struct {
	uint8_t type;
	int8_t matrix[5];
} __attribute__((packed)) Mixer_t;

/**
 * @brief Module initialization
 * @return 0
 */
int32_t ActuatorStart()
{
	// Start main task
	xTaskCreate(actuatorTask, (signed char*)"Actuator", STACK_SIZE_BYTES/4, NULL, TASK_PRIORITY, &taskHandle);
	PIOS_TASK_MONITOR_RegisterTask(TASKINFO_RUNNING_ACTUATOR, taskHandle);
#ifdef PIOS_INCLUDE_WDG
	PIOS_WDG_RegisterFlag(PIOS_WDG_ACTUATOR);
#endif

	return 0;
}

/**
 * @brief Module initialization
 * @return 0
 */
int32_t ActuatorInitialize()
{
	// Register for notification of changes to ActuatorSettings
	ActuatorSettingsInitialize();
	ActuatorSettingsConnectCallback(ActuatorSettingsUpdatedCb);

	// Register for notification of changes to MixerSettings
	MixerSettingsInitialize();
	MixerSettingsConnectCallback(MixerSettingsUpdatedCb);

	// Listen for ActuatorDesired updates (Primary input to this module)
	ActuatorDesiredInitialize();
	queue = xQueueCreate(MAX_QUEUE_SIZE, sizeof(UAVObjEvent));
	ActuatorDesiredConnectQueue(queue);

	// Primary output of this module
	ActuatorCommandInitialize();

#ifdef DIAG_MIXERSTATUS
	// UAVO only used for inspecting the internal status of the mixer during debug
	MixerStatusInitialize();
#endif

	return 0;
}
MODULE_INITCALL(ActuatorInitialize, ActuatorStart)

/**
 * @brief Main Actuator module task
 *
 * Universal matrix based mixer for VTOL, helis and fixed wing.
 * Converts desired roll,pitch,yaw and throttle to servo/ESC outputs.
 *
 * Because of how the Throttle ranges from 0 to 1, the motors should too!
 *
 * Note this code depends on the UAVObjects for the mixers being all being the same
 * and in sequence. If you change the object definition, make sure you check the code!
 *
 * @return -1 if error, 0 if success
 */
static void actuatorTask(__attribute__((unused)) void* parameters)
{
	UAVObjEvent ev;
	portTickType lastSysTime;
	portTickType thisSysTime;
	float dTSeconds;
	uint32_t dTMilliseconds;

	ActuatorCommandData command;
	ActuatorDesiredData desired;
	MixerStatusData mixerStatus;
	FlightStatusData flightStatus;

	/* Read initial values of ActuatorSettings */
	ActuatorSettingsData actuatorSettings;
	actuator_settings_updated = false;
	ActuatorSettingsGet(&actuatorSettings);

	/* Read initial values of MixerSettings */
	MixerSettingsData mixerSettings;
	mixer_settings_updated = false;
	MixerSettingsGet(&mixerSettings);

	/* Force an initial configuration of the actuator update rates */
	actuator_update_rate_if_changed(&actuatorSettings, true);

	// Go to the neutral (failsafe) values until an ActuatorDesired update is received
	setFailsafe(&actuatorSettings, &mixerSettings);

	// Main task loop
	lastSysTime = xTaskGetTickCount();
	while (1)
	{
#ifdef PIOS_INCLUDE_WDG
		PIOS_WDG_UpdateFlag(PIOS_WDG_ACTUATOR);
#endif

		// Wait until the ActuatorDesired object is updated
		uint8_t rc = xQueueReceive(queue, &ev, FAILSAFE_TIMEOUT_MS / portTICK_RATE_MS);

		/* Process settings updated events even in timeout case so we always act on the latest settings */
		if (actuator_settings_updated) {
			actuator_settings_updated = false;
			ActuatorSettingsGet (&actuatorSettings);
			actuator_update_rate_if_changed (&actuatorSettings, false);
		}
		if (mixer_settings_updated) {
			mixer_settings_updated = false;
			MixerSettingsGet (&mixerSettings);
		}

		if (rc != pdTRUE) {
			/* Update of ActuatorDesired timed out.  Go to failsafe */
			setFailsafe(&actuatorSettings, &mixerSettings);
			continue;
		}

		// Check how long since last update
		thisSysTime = xTaskGetTickCount();
		dTMilliseconds = (thisSysTime == lastSysTime)? 1: (thisSysTime - lastSysTime) * portTICK_RATE_MS;
		lastSysTime = thisSysTime;
		dTSeconds = dTMilliseconds * 0.001f;

		FlightStatusGet(&flightStatus);
		ActuatorDesiredGet(&desired);
		ActuatorCommandGet(&command);

#ifdef DIAG_MIXERSTATUS
		MixerStatusGet(&mixerStatus);
#endif
		int nMixers = 0;
		Mixer_t * mixers = (Mixer_t *)&mixerSettings.Mixer1Type;
		for(int ct=0; ct < MAX_MIX_ACTUATORS; ct++)
		{
			if(mixers[ct].type != MIXERSETTINGS_MIXER1TYPE_DISABLED)
			{
				nMixers ++;
			}
		}
		if((nMixers < 2) && !ActuatorCommandReadOnly()) //Nothing can fly with less than two mixers.
		{
			setFailsafe(&actuatorSettings, &mixerSettings); // So that channels like PWM buzzer keep working
			continue;
		}

		AlarmsClear(SYSTEMALARMS_ALARM_ACTUATOR);

		bool armed = flightStatus.Armed == FLIGHTSTATUS_ARMED_ARMED;
		bool positiveThrottle = desired.Throttle >= 0.00f;
		bool spinWhileArmed = actuatorSettings.MotorsSpinWhileArmed == ACTUATORSETTINGS_MOTORSSPINWHILEARMED_TRUE;

		float curve1 = MixerCurve(desired.Throttle,mixerSettings.ThrottleCurve1,MIXERSETTINGS_THROTTLECURVE1_NUMELEM);
		
		//The source for the secondary curve is selectable
		float curve2 = 0;
		AccessoryDesiredData accessory;
		switch(mixerSettings.Curve2Source) {
			case MIXERSETTINGS_CURVE2SOURCE_THROTTLE:
				curve2 = MixerCurve(desired.Throttle,mixerSettings.ThrottleCurve2,MIXERSETTINGS_THROTTLECURVE2_NUMELEM);
				break;
			case MIXERSETTINGS_CURVE2SOURCE_ROLL:
				curve2 = MixerCurve(desired.Roll,mixerSettings.ThrottleCurve2,MIXERSETTINGS_THROTTLECURVE2_NUMELEM);
				break;
			case MIXERSETTINGS_CURVE2SOURCE_PITCH:
				curve2 = MixerCurve(desired.Pitch,mixerSettings.ThrottleCurve2,
				MIXERSETTINGS_THROTTLECURVE2_NUMELEM);
				break;
			case MIXERSETTINGS_CURVE2SOURCE_YAW:
				curve2 = MixerCurve(desired.Yaw,mixerSettings.ThrottleCurve2,MIXERSETTINGS_THROTTLECURVE2_NUMELEM);
				break;
			case MIXERSETTINGS_CURVE2SOURCE_COLLECTIVE:
				ManualControlCommandCollectiveGet(&curve2);
				curve2 = MixerCurve(curve2,mixerSettings.ThrottleCurve2,
				MIXERSETTINGS_THROTTLECURVE2_NUMELEM);
				break;
			case MIXERSETTINGS_CURVE2SOURCE_ACCESSORY0:
			case MIXERSETTINGS_CURVE2SOURCE_ACCESSORY1:
			case MIXERSETTINGS_CURVE2SOURCE_ACCESSORY2:
			case MIXERSETTINGS_CURVE2SOURCE_ACCESSORY3:
			case MIXERSETTINGS_CURVE2SOURCE_ACCESSORY4:
			case MIXERSETTINGS_CURVE2SOURCE_ACCESSORY5:
				if(AccessoryDesiredInstGet(mixerSettings.Curve2Source - MIXERSETTINGS_CURVE2SOURCE_ACCESSORY0,&accessory) == 0)
					curve2 = MixerCurve(accessory.AccessoryVal,mixerSettings.ThrottleCurve2,MIXERSETTINGS_THROTTLECURVE2_NUMELEM);
				else
					curve2 = 0;
				break;
		}

		float * status = (float *)&mixerStatus; //access status objects as an array of floats

		for(int ct=0; ct < MAX_MIX_ACTUATORS; ct++)
		{
			// During boot all camera actuators should be completely disabled (PWM pulse = 0).
			// command.Channel[i] is reused below as a channel PWM activity flag:
			// 0 - PWM disabled, >0 - PWM set to real mixer value using scaleChannel() later.
			// Setting it to 1 by default means "Rescale this channel and enable PWM on its output".
			command.Channel[ct] = 1;

			if(mixers[ct].type == MIXERSETTINGS_MIXER1TYPE_DISABLED) {
				// Set to minimum if disabled.  This is not the same as saying PWM pulse = 0 us
				status[ct] = -1;
				continue;
			}

			if((mixers[ct].type == MIXERSETTINGS_MIXER1TYPE_MOTOR) || (mixers[ct].type == MIXERSETTINGS_MIXER1TYPE_SERVO))
				status[ct] = ProcessMixer(ct, curve1, curve2, &mixerSettings, &desired, dTSeconds);
			else
				status[ct] = -1;

			// Motors have additional protection for when to be on
			if(mixers[ct].type == MIXERSETTINGS_MIXER1TYPE_MOTOR) {

				// If not armed or motors aren't meant to spin all the time
				if( !armed ||
				   (!spinWhileArmed && !positiveThrottle))
				{
					filterAccumulator[ct] = 0;
					lastResult[ct] = 0;
					status[ct] = -1;  //force min throttle
				}
				// If armed meant to keep spinning,
				else if ((spinWhileArmed && !positiveThrottle) ||
					 (status[ct] < 0) )
					status[ct] = 0;
			}

			// If an accessory channel is selected for direct bypass mode
			// In this configuration the accessory channel is scaled and mapped
			// directly to output.  Note: THERE IS NO SAFETY CHECK HERE FOR ARMING
			// these also will not be updated in failsafe mode.  I'm not sure what
			// the correct behavior is since it seems domain specific.  I don't love
			// this code
			if( (mixers[ct].type >= MIXERSETTINGS_MIXER1TYPE_ACCESSORY0) &&
			   (mixers[ct].type <= MIXERSETTINGS_MIXER1TYPE_ACCESSORY5))
			{
				if(AccessoryDesiredInstGet(mixers[ct].type - MIXERSETTINGS_MIXER1TYPE_ACCESSORY0,&accessory) == 0)
					status[ct] = accessory.AccessoryVal;
				else
					status[ct] = -1;
			}

			if( (mixers[ct].type >= MIXERSETTINGS_MIXER1TYPE_CAMERAROLLORSERVO1) &&
			   (mixers[ct].type <= MIXERSETTINGS_MIXER1TYPE_CAMERAYAW))
			{
				CameraDesiredData cameraDesired;
				if( CameraDesiredGet(&cameraDesired) == 0 ) {
					switch(mixers[ct].type) {
						case MIXERSETTINGS_MIXER1TYPE_CAMERAROLLORSERVO1:
							status[ct] = cameraDesired.RollOrServo1;
							break;
						case MIXERSETTINGS_MIXER1TYPE_CAMERAPITCHORSERVO2:
							status[ct] = cameraDesired.PitchOrServo2;
							break;
						case MIXERSETTINGS_MIXER1TYPE_CAMERAYAW:
							status[ct] = cameraDesired.Yaw;
							break;
						default:
							break;
					}
				}
				else
					status[ct] = -1;

				// Disable camera actuators for CAMERA_BOOT_DELAY_MS after boot
				if (thisSysTime < (CAMERA_BOOT_DELAY_MS / portTICK_RATE_MS))
					command.Channel[ct] = 0;
			}
		}

		// Set real actuator output values scaling them from mixers. All channels
		// will be set except explicitly disabled (which will have PWM pulse = 0).
		for (int i = 0; i < MAX_MIX_ACTUATORS; i++)
			if (command.Channel[i])
				command.Channel[i] = scaleChannel(status[i],
							   actuatorSettings.ChannelMax[i],
							   actuatorSettings.ChannelMin[i],
							   actuatorSettings.ChannelNeutral[i]);

		// Store update time
		command.UpdateTime = dTMilliseconds;
		if (command.UpdateTime > command.MaxUpdateTime)
			command.MaxUpdateTime = command.UpdateTime;
		
		// Update output object
		ActuatorCommandSet(&command);
		// Update in case read only (eg. during servo configuration)
		ActuatorCommandGet(&command);

#ifdef DIAG_MIXERSTATUS
		MixerStatusSet(&mixerStatus);
#endif
		

		// Update servo outputs
		bool success = true;

		for (int n = 0; n < ACTUATORCOMMAND_CHANNEL_NUMELEM; ++n)
		{
			success &= set_channel(n, command.Channel[n], &actuatorSettings);
		}

		if(!success) {
			command.NumFailedUpdates++;
			ActuatorCommandSet(&command);
			AlarmsSet(SYSTEMALARMS_ALARM_ACTUATOR, SYSTEMALARMS_ALARM_CRITICAL);
		}

	}
}



/**
 *Process mixing for one actuator
 */
float ProcessMixer(const int index, const float curve1, const float curve2,
		   const MixerSettingsData* mixerSettings, ActuatorDesiredData* desired, const float period)
{
	static float lastFilteredResult[MAX_MIX_ACTUATORS];
	const Mixer_t * mixers = (Mixer_t *)&mixerSettings->Mixer1Type; //pointer to array of mixers in UAVObjects
	const Mixer_t * mixer = &mixers[index];

	float result = (((float)mixer->matrix[MIXERSETTINGS_MIXER1VECTOR_THROTTLECURVE1] / 128.0f) * curve1) +
		       (((float)mixer->matrix[MIXERSETTINGS_MIXER1VECTOR_THROTTLECURVE2] / 128.0f) * curve2) +
		       (((float)mixer->matrix[MIXERSETTINGS_MIXER1VECTOR_ROLL] / 128.0f) * desired->Roll) +
		       (((float)mixer->matrix[MIXERSETTINGS_MIXER1VECTOR_PITCH] / 128.0f) * desired->Pitch) +
		       (((float)mixer->matrix[MIXERSETTINGS_MIXER1VECTOR_YAW] / 128.0f) * desired->Yaw);

	if(mixer->type == MIXERSETTINGS_MIXER1TYPE_MOTOR)
	{
		if(result < 0.0f) //idle throttle
		{
			result = 0.0f;
		}

		//feed forward
		float accumulator = filterAccumulator[index];
		accumulator += (result - lastResult[index]) * mixerSettings->FeedForward;
		lastResult[index] = result;
		result += accumulator;
		if(period > 0.0f)
		{
			if(accumulator > 0.0f)
			{
				float filter = mixerSettings->AccelTime / period;
				if(filter <1)
				{
					filter = 1;
				}
				accumulator -= accumulator / filter;
			}else
			{
				float filter = mixerSettings->DecelTime / period;
				if(filter <1)
				{
					filter = 1;
				}
				accumulator -= accumulator / filter;
			}
		}
		filterAccumulator[index] = accumulator;
		result += accumulator;

		//acceleration limit
		float dt = result - lastFilteredResult[index];
		float maxDt = mixerSettings->MaxAccel * period;
		if(dt > maxDt) //we are accelerating too hard
		{
			result = lastFilteredResult[index] + maxDt;
		}
		lastFilteredResult[index] = result;
	}

	return(result);
}


/**
 *Interpolate a throttle curve. Throttle input should be in the range 0 to 1.
 *Output is in the range 0 to 1.
 */
static float MixerCurve(const float throttle, const float* curve, uint8_t elements)
{
	float scale = throttle * (float) (elements - 1);
	int idx1 = scale;
	scale -= (float)idx1; //remainder
	if(curve[0] < -1)
	{
		return(throttle);
	}
	if (idx1 < 0)
	{
		idx1 = 0; //clamp to lowest entry in table
		scale = 0;
	}
	int idx2 = idx1 + 1;
	if(idx2 >= elements)
	{
		idx2 = elements -1; //clamp to highest entry in table
		if(idx1 >= elements)
		{
			idx1 = elements -1;
		}
	}
	return curve[idx1] * (1.0f - scale) + curve[idx2] * scale;
}


/**
 * Convert channel from -1/+1 to servo pulse duration in microseconds
 */
static int16_t scaleChannel(float value, int16_t max, int16_t min, int16_t neutral)
{
	int16_t valueScaled;
	// Scale
	if ( value >= 0.0f)
	{
		valueScaled = (int16_t)(value*((float)(max-neutral))) + neutral;
	}
	else
	{
		valueScaled = (int16_t)(value*((float)(neutral-min))) + neutral;
	}

	if (max>min)
	{
		if( valueScaled > max ) valueScaled = max;
		if( valueScaled < min ) valueScaled = min;
	}
	else
	{
		if( valueScaled < max ) valueScaled = max;
		if( valueScaled > min ) valueScaled = min;
	}

	return valueScaled;
}

/**
 * Set actuator output to the neutral values (failsafe)
 */
static void setFailsafe(const ActuatorSettingsData * actuatorSettings, const MixerSettingsData * mixerSettings)
{
	/* grab only the parts that we are going to use */
	int16_t Channel[ACTUATORCOMMAND_CHANNEL_NUMELEM];
	ActuatorCommandChannelGet(Channel);

	const Mixer_t * mixers = (Mixer_t *)&mixerSettings->Mixer1Type; //pointer to array of mixers in UAVObjects

	// Reset ActuatorCommand to safe values
	for (int n = 0; n < ACTUATORCOMMAND_CHANNEL_NUMELEM; ++n)
	{

		if(mixers[n].type == MIXERSETTINGS_MIXER1TYPE_MOTOR)
		{
			Channel[n] = actuatorSettings->ChannelMin[n];
		}
		else if(mixers[n].type == MIXERSETTINGS_MIXER1TYPE_SERVO)
		{
			Channel[n] = actuatorSettings->ChannelNeutral[n];
		}
		else
		{
			Channel[n] = 0;
		}
		
		
	}

	// Set alarm
	AlarmsSet(SYSTEMALARMS_ALARM_ACTUATOR, SYSTEMALARMS_ALARM_CRITICAL);

	// Update servo outputs
	for (int n = 0; n < ACTUATORCOMMAND_CHANNEL_NUMELEM; ++n)
	{
		set_channel(n, Channel[n], actuatorSettings);
	}

	// Update output object's parts that we changed
	ActuatorCommandChannelSet(Channel);
}

/**
 * determine buzzer or blink sequence
 **/

typedef enum {BUZZ_BUZZER=0,BUZZ_ARMING=1,BUZZ_INFO=2,BUZZ_MAX=3} buzzertype;

static inline bool buzzerState(buzzertype type)
{
	// This is for buzzers that take a PWM input

	static uint32_t tune[BUZZ_MAX]={0};
	static uint32_t tunestate[BUZZ_MAX]={0};


	uint32_t newTune = 0;
	if(type==BUZZ_BUZZER)
	{
		// Decide what tune to play
		if (AlarmsGet(SYSTEMALARMS_ALARM_BATTERY) > SYSTEMALARMS_ALARM_WARNING) {
			newTune = 0b11110110110000;	// pause, short, short, short, long
		} else if (AlarmsGet(SYSTEMALARMS_ALARM_GPS) >= SYSTEMALARMS_ALARM_WARNING) {
			newTune = 0x80000000;			// pause, short
		} else {
			newTune = 0;
		}

	} else { // BUZZ_ARMING || BUZZ_INFO
		uint8_t arming;
		FlightStatusArmedGet(&arming);
		//base idle tune  
		newTune =  0x80000000;	  // 0b1000...
		
		// Merge the error pattern for InfoLed
		if(type==BUZZ_INFO)
		{
			if (AlarmsGet(SYSTEMALARMS_ALARM_BATTERY) > SYSTEMALARMS_ALARM_WARNING) 
			{
				newTune |= 0b00000000001111111011111110000000;
			}
			else if(AlarmsGet(SYSTEMALARMS_ALARM_GPS) >= SYSTEMALARMS_ALARM_WARNING) 
			{			 
				newTune |= 0b00000000000000110110110000000000;
			}
		}
		// fast double blink pattern if armed 
		if (arming == FLIGHTSTATUS_ARMED_ARMED) 
		   newTune |= 0xA0000000;   // 0b101000... 

	}

	// Do we need to change tune?
	if (newTune != tune[type]) {
		tune[type] = newTune;
		// resynchronize all tunes on change, so they stay in sync
		for (int i=0;i<BUZZ_MAX;i++) {
			tunestate[i] = tune[i];
		}
	}

	// Play tune
	bool buzzOn = false;
	static portTickType lastSysTime = 0;
	portTickType thisSysTime = xTaskGetTickCount();
	portTickType dT = 0;

	// For now, only look at the battery alarm, because functions like AlarmsHasCritical() can block for some time; to be discussed
	if (tune[type]) {
		if(thisSysTime > lastSysTime) {
			dT = thisSysTime - lastSysTime;
		} else {
			lastSysTime = 0; // avoid the case where SysTimeMax-lastSysTime <80
		}

		buzzOn = (tunestate[type]&1);

		if (dT > 80) {
			// Go to next bit in alarm_seq_state
			for (int i=0;i<BUZZ_MAX;i++) {
				tunestate[i] >>=1;
				if (tunestate[i]==0) // All done, re-start the tune
					tunestate[i]=tune[i];
			}
			lastSysTime = thisSysTime;
		}
	}
	return buzzOn;
}


#if defined(ARCH_POSIX) || defined(ARCH_WIN32)
static bool set_channel(uint8_t mixer_channel, uint16_t value, const ActuatorSettingsData * actuatorSettings)
{
	return true;
}
#else
static bool set_channel(uint8_t mixer_channel, uint16_t value, const ActuatorSettingsData * actuatorSettings)
{
	switch(actuatorSettings->ChannelType[mixer_channel]) {
		case ACTUATORSETTINGS_CHANNELTYPE_PWMALARMBUZZER: 
			PIOS_Servo_Set(actuatorSettings->ChannelAddr[mixer_channel],
			              buzzerState(BUZZ_BUZZER)?actuatorSettings->ChannelMax[mixer_channel]:actuatorSettings->ChannelMin[mixer_channel]);
			return true;
		case ACTUATORSETTINGS_CHANNELTYPE_ARMINGLED:
			PIOS_Servo_Set(actuatorSettings->ChannelAddr[mixer_channel],
			              buzzerState(BUZZ_ARMING)?actuatorSettings->ChannelMax[mixer_channel]:actuatorSettings->ChannelMin[mixer_channel]);
			return true;
		case ACTUATORSETTINGS_CHANNELTYPE_INFOLED:
			PIOS_Servo_Set(actuatorSettings->ChannelAddr[mixer_channel],
			              buzzerState(BUZZ_INFO)?actuatorSettings->ChannelMax[mixer_channel]:actuatorSettings->ChannelMin[mixer_channel]);
			return true;
		case ACTUATORSETTINGS_CHANNELTYPE_PWM:
			PIOS_Servo_Set(actuatorSettings->ChannelAddr[mixer_channel], value);
			return true;
#if defined(PIOS_INCLUDE_I2C_ESC)
		case ACTUATORSETTINGS_CHANNELTYPE_MK:
			return PIOS_SetMKSpeed(actuatorSettings->ChannelAddr[mixer_channel],value);
		case ACTUATORSETTINGS_CHANNELTYPE_ASTEC4:
			return PIOS_SetAstec4Speed(actuatorSettings->ChannelAddr[mixer_channel],value);
#endif
		default:
			return false;
	}

	return false;

}
#endif

/**
 * @brief Update the servo update rate
 */
static void actuator_update_rate_if_changed(const ActuatorSettingsData * actuatorSettings, bool force_update)
{
	static uint16_t prevChannelUpdateFreq[ACTUATORSETTINGS_CHANNELUPDATEFREQ_NUMELEM];

	// check if the any rate setting is changed
	if (force_update ||
		memcmp (prevChannelUpdateFreq,
			actuatorSettings->ChannelUpdateFreq,
			sizeof(prevChannelUpdateFreq)) != 0) {
		/* Something has changed, apply the settings to HW */
		memcpy (prevChannelUpdateFreq,
			actuatorSettings->ChannelUpdateFreq,
			sizeof(prevChannelUpdateFreq));
		PIOS_Servo_SetHz(actuatorSettings->ChannelUpdateFreq, ACTUATORSETTINGS_CHANNELUPDATEFREQ_NUMELEM);
	}
}

static void ActuatorSettingsUpdatedCb(__attribute__((unused)) UAVObjEvent *ev)
{
	actuator_settings_updated = true;
}

static void MixerSettingsUpdatedCb(__attribute__((unused)) UAVObjEvent *ev)
{
	mixer_settings_updated = true;
}

/**
 * @}
 * @}
 */