PrusaFirmware/Firmware/temperature.cpp

/*
  temperature.c - temperature control
  Part of Marlin
  
 Copyright (C) 2011 Camiel Gubbels / Erik van der Zalm
 
 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, see <http://www.gnu.org/licenses/>.
 */

/*
 This firmware is a mashup between Sprinter and grbl.
  (https://github.com/kliment/Sprinter)
  (https://github.com/simen/grbl/tree)
 
 It has preliminary support for Matthew Roberts advance algorithm 
    http://reprap.org/pipermail/reprap-dev/2011-May/003323.html

 */


#include "Marlin.h"
#include "cmdqueue.h"
#include "ultralcd.h"
#include "menu.h"
#include "conv2str.h"
#include "sound.h"
#include "temperature.h"
#include "cardreader.h"

#include "SdFatUtil.h"

#include <avr/wdt.h>
#include "adc.h"
#include "ConfigurationStore.h"
#include "messages.h"
#include "Timer.h"
#include "Configuration_prusa.h"

#include "config.h"

//===========================================================================
//=============================public variables============================
//===========================================================================
int target_temperature[EXTRUDERS] = { 0 };
int target_temperature_bed = 0;
int current_temperature_raw[EXTRUDERS] = { 0 };
float current_temperature[EXTRUDERS] = { 0.0 };

#ifdef PINDA_THERMISTOR
uint16_t current_temperature_raw_pinda =  0 ; //value with more averaging applied
uint16_t current_temperature_raw_pinda_fast = 0; //value read from adc
float current_temperature_pinda = 0.0;
#endif //PINDA_THERMISTOR

#ifdef AMBIENT_THERMISTOR
int current_temperature_raw_ambient =  0 ;
float current_temperature_ambient = 0.0;
#endif //AMBIENT_THERMISTOR

#ifdef VOLT_PWR_PIN
int current_voltage_raw_pwr = 0;
#endif

#ifdef VOLT_BED_PIN
int current_voltage_raw_bed = 0;
#endif

#ifdef IR_SENSOR_ANALOG
uint16_t current_voltage_raw_IR = 0;
#endif //IR_SENSOR_ANALOG

int current_temperature_bed_raw = 0;
float current_temperature_bed = 0.0;
  

#ifdef PIDTEMP
  float _Kp, _Ki, _Kd;
  int pid_cycle, pid_number_of_cycles;
  bool pid_tuning_finished = false;
  #ifdef PID_ADD_EXTRUSION_RATE
    float Kc=DEFAULT_Kc;
  #endif
#endif //PIDTEMP
  
#ifdef FAN_SOFT_PWM
  unsigned char fanSpeedSoftPwm;
#endif

#ifdef FANCHECK
  volatile uint8_t fan_check_error = EFCE_OK;
#endif

unsigned char soft_pwm_bed;

#ifdef BABYSTEPPING
  volatile int babystepsTodo[3]={0,0,0};
#endif

//===========================================================================
//=============================private variables============================
//===========================================================================
static volatile bool temp_meas_ready = false;

#ifdef PIDTEMP
  //static cannot be external:
  static float iState_sum[EXTRUDERS] = { 0 };
  static float dState_last[EXTRUDERS] = { 0 };
  static float pTerm[EXTRUDERS];
  static float iTerm[EXTRUDERS];
  static float dTerm[EXTRUDERS];
  //int output;
  static float pid_error[EXTRUDERS];
  static float iState_sum_min[EXTRUDERS];
  static float iState_sum_max[EXTRUDERS];
  // static float pid_input[EXTRUDERS];
  // static float pid_output[EXTRUDERS];
  static bool pid_reset[EXTRUDERS];
#endif //PIDTEMP
#ifdef PIDTEMPBED
  //static cannot be external:
  static float temp_iState_bed = { 0 };
  static float temp_dState_bed = { 0 };
  static float pTerm_bed;
  static float iTerm_bed;
  static float dTerm_bed;
  //int output;
  static float pid_error_bed;
  static float temp_iState_min_bed;
  static float temp_iState_max_bed;
#else //PIDTEMPBED
	static unsigned long  previous_millis_bed_heater;
#endif //PIDTEMPBED
  static unsigned char soft_pwm[EXTRUDERS];

#ifdef FAN_SOFT_PWM
  static unsigned char soft_pwm_fan;
#endif

uint8_t fanSpeedBckp = 255;

#if (defined(EXTRUDER_0_AUTO_FAN_PIN) && EXTRUDER_0_AUTO_FAN_PIN > -1)
  unsigned long extruder_autofan_last_check = _millis();
  
  bool fan_measuring = false;
  uint8_t fanState = 0;
#ifdef EXTRUDER_ALTFAN_DETECT
  struct
  {
    uint8_t isAltfan : 1;
    uint8_t altfanOverride : 1;
  } altfanStatus;
#endif //EXTRUDER_ALTFAN_DETECT
#endif


#if EXTRUDERS > 3
  # error Unsupported number of extruders
#elif EXTRUDERS > 2
  # define ARRAY_BY_EXTRUDERS(v1, v2, v3) { v1, v2, v3 }
#elif EXTRUDERS > 1
  # define ARRAY_BY_EXTRUDERS(v1, v2, v3) { v1, v2 }
#else
  # define ARRAY_BY_EXTRUDERS(v1, v2, v3) { v1 }
#endif

static ShortTimer oTimer4minTempHeater,oTimer4minTempBed;

// Init min and max temp with extreme values to prevent false errors during startup
static int minttemp_raw[EXTRUDERS] = ARRAY_BY_EXTRUDERS( HEATER_0_RAW_LO_TEMP , HEATER_1_RAW_LO_TEMP , HEATER_2_RAW_LO_TEMP );
static int maxttemp_raw[EXTRUDERS] = ARRAY_BY_EXTRUDERS( HEATER_0_RAW_HI_TEMP , HEATER_1_RAW_HI_TEMP , HEATER_2_RAW_HI_TEMP );
static int minttemp[EXTRUDERS] = ARRAY_BY_EXTRUDERS( 0, 0, 0 );
static int maxttemp[EXTRUDERS] = ARRAY_BY_EXTRUDERS( 16383, 16383, 16383 );
#ifdef BED_MINTEMP
static int bed_minttemp_raw = HEATER_BED_RAW_LO_TEMP;
#endif
#ifdef BED_MAXTEMP
static int bed_maxttemp_raw = HEATER_BED_RAW_HI_TEMP;
#endif
#ifdef AMBIENT_MINTEMP
static int ambient_minttemp_raw = AMBIENT_RAW_LO_TEMP;
#endif
#ifdef AMBIENT_MAXTEMP
static int ambient_maxttemp_raw = AMBIENT_RAW_HI_TEMP;
#endif

static void *heater_ttbl_map[EXTRUDERS] = ARRAY_BY_EXTRUDERS( (void *)HEATER_0_TEMPTABLE, (void *)HEATER_1_TEMPTABLE, (void *)HEATER_2_TEMPTABLE );
static uint8_t heater_ttbllen_map[EXTRUDERS] = ARRAY_BY_EXTRUDERS( HEATER_0_TEMPTABLE_LEN, HEATER_1_TEMPTABLE_LEN, HEATER_2_TEMPTABLE_LEN );

static float analog2temp(int raw, uint8_t e);
static float analog2tempBed(int raw);
#ifdef AMBIENT_MAXTEMP
static float analog2tempAmbient(int raw);
#endif
static void updateTemperaturesFromRawValues();

enum TempRunawayStates : uint8_t
{
	TempRunaway_INACTIVE = 0,
	TempRunaway_PREHEAT = 1,
	TempRunaway_ACTIVE = 2,
};

#ifndef SOFT_PWM_SCALE
#define SOFT_PWM_SCALE 0
#endif

//===========================================================================
//=============================   functions      ============================
//===========================================================================

#if (defined (TEMP_RUNAWAY_BED_HYSTERESIS) && TEMP_RUNAWAY_BED_TIMEOUT > 0) || (defined (TEMP_RUNAWAY_EXTRUDER_HYSTERESIS) && TEMP_RUNAWAY_EXTRUDER_TIMEOUT > 0)
static uint8_t temp_runaway_status[1 + EXTRUDERS];
static float temp_runaway_target[1 + EXTRUDERS];
static uint32_t temp_runaway_timer[1 + EXTRUDERS];
static uint16_t temp_runaway_error_counter[1 + EXTRUDERS];

static void temp_runaway_check(uint8_t _heater_id, float _target_temperature, float _current_temperature, float _output, bool _isbed);
static void temp_runaway_stop(bool isPreheat, bool isBed);
#endif

#ifdef EXTRUDER_ALTFAN_DETECT
ISR(INT6_vect) {
	fan_edge_counter[0]++;
}

bool extruder_altfan_detect()
{
	setExtruderAutoFanState(3);

	SET_INPUT(TACH_0);

	uint8_t overrideVal = eeprom_read_byte((uint8_t *)EEPROM_ALTFAN_OVERRIDE);
	if (overrideVal == EEPROM_EMPTY_VALUE)
	{
		overrideVal = (calibration_status() == CALIBRATION_STATUS_CALIBRATED) ? 1 : 0;
		eeprom_update_byte((uint8_t *)EEPROM_ALTFAN_OVERRIDE, overrideVal);
	}
	altfanStatus.altfanOverride = overrideVal;

	CRITICAL_SECTION_START;
	EICRB &= ~(1 << ISC61);
	EICRB |= (1 << ISC60);
	EIMSK |= (1 << INT6);
	fan_edge_counter[0] = 0;
	CRITICAL_SECTION_END;
	extruder_autofan_last_check = _millis();

	_delay(1000);

	EIMSK &= ~(1 << INT6);

	countFanSpeed();
	altfanStatus.isAltfan = fan_speed[0] > 100;
	setExtruderAutoFanState(1);
	return altfanStatus.isAltfan;
}

void altfanOverride_toggle()
{
    altfanStatus.altfanOverride = !altfanStatus.altfanOverride;
    eeprom_update_byte((uint8_t *)EEPROM_ALTFAN_OVERRIDE, altfanStatus.altfanOverride);
}

bool altfanOverride_get()
{
    return altfanStatus.altfanOverride;
}

#endif //EXTRUDER_ALTFAN_DETECT

// return "false", if all extruder-heaters are 'off' (ie. "true", if any heater is 'on')
bool checkAllHotends(void)
{
    bool result=false;
    for(int i=0;i<EXTRUDERS;i++) result=(result||(target_temperature[i]!=0));
    return(result);
}

// WARNING: the following function has been marked noinline to avoid a GCC 4.9.2 LTO
//          codegen bug causing a stack overwrite issue in process_commands()
void __attribute__((noinline)) PID_autotune(float temp, int extruder, int ncycles)
{
  pid_number_of_cycles = ncycles;
  pid_tuning_finished = false;
  float input = 0.0;
  pid_cycle=0;
  bool heating = true;

  unsigned long temp_millis = _millis();
  unsigned long t1=temp_millis;
  unsigned long t2=temp_millis;
  long t_high = 0;
  long t_low = 0;

  long bias, d;
  float Ku, Tu;
  float max = 0, min = 10000;
  uint8_t safety_check_cycles = 0;
  const uint8_t safety_check_cycles_count = (extruder < 0) ? 45 : 10; //10 cycles / 20s delay for extruder and 45 cycles / 90s for heatbed
  float temp_ambient;

#if (defined(EXTRUDER_0_AUTO_FAN_PIN) && EXTRUDER_0_AUTO_FAN_PIN > -1)
  unsigned long extruder_autofan_last_check = _millis();
#endif

  if ((extruder >= EXTRUDERS)
  #if (TEMP_BED_PIN <= -1)
       ||(extruder < 0)
  #endif
       ){
          SERIAL_ECHOLN("PID Autotune failed. Bad extruder number.");
		  pid_tuning_finished = true;
		  pid_cycle = 0;
          return;
        }
	
  SERIAL_ECHOLN("PID Autotune start");
  
  disable_heater(); // switch off all heaters.

  if (extruder<0)
  {
     soft_pwm_bed = (MAX_BED_POWER)/2;
	 timer02_set_pwm0(soft_pwm_bed << 1);
     bias = d = (MAX_BED_POWER)/2;
     target_temperature_bed = (int)temp; // to display the requested target bed temperature properly on the main screen
   }
   else
   {
     soft_pwm[extruder] = (PID_MAX)/2;
     bias = d = (PID_MAX)/2;
     target_temperature[extruder] = (int)temp; // to display the requested target extruder temperature properly on the main screen
  }




 for(;;) {
#ifdef WATCHDOG
    wdt_reset();
#endif //WATCHDOG
    if(temp_meas_ready == true) { // temp sample ready
      updateTemperaturesFromRawValues();

      input = (extruder<0)?current_temperature_bed:current_temperature[extruder];

      max=max(max,input);
      min=min(min,input);

      #if (defined(EXTRUDER_0_AUTO_FAN_PIN) && EXTRUDER_0_AUTO_FAN_PIN > -1)
      if(_millis() - extruder_autofan_last_check > 2500) {
        checkExtruderAutoFans();
        extruder_autofan_last_check = _millis();
      }
      #endif

      if(heating == true && input > temp) {
        if(_millis() - t2 > 5000) { 
          heating=false;
          if (extruder<0)
		  {
            soft_pwm_bed = (bias - d) >> 1;
			timer02_set_pwm0(soft_pwm_bed << 1);
		  }
          else
            soft_pwm[extruder] = (bias - d) >> 1;
          t1=_millis();
          t_high=t1 - t2;
          max=temp;
        }
      }
      if(heating == false && input < temp) {
        if(_millis() - t1 > 5000) {
          heating=true;
          t2=_millis();
          t_low=t2 - t1;
          if(pid_cycle > 0) {
            bias += (d*(t_high - t_low))/(t_low + t_high);
            bias = constrain(bias, 20 ,(extruder<0?(MAX_BED_POWER):(PID_MAX))-20);
            if(bias > (extruder<0?(MAX_BED_POWER):(PID_MAX))/2) d = (extruder<0?(MAX_BED_POWER):(PID_MAX)) - 1 - bias;
            else d = bias;

            SERIAL_PROTOCOLPGM(" bias: "); SERIAL_PROTOCOL(bias);
            SERIAL_PROTOCOLPGM(" d: "); SERIAL_PROTOCOL(d);
            SERIAL_PROTOCOLPGM(" min: "); SERIAL_PROTOCOL(min);
            SERIAL_PROTOCOLPGM(" max: "); SERIAL_PROTOCOLLN(max);
            if(pid_cycle > 2) {
              Ku = (4.0*d)/(3.14159*(max-min)/2.0);
              Tu = ((float)(t_low + t_high)/1000.0);
              SERIAL_PROTOCOLPGM(" Ku: "); SERIAL_PROTOCOL(Ku);
              SERIAL_PROTOCOLPGM(" Tu: "); SERIAL_PROTOCOLLN(Tu);
              _Kp = 0.6*Ku;
              _Ki = 2*_Kp/Tu;
              _Kd = _Kp*Tu/8;
              SERIAL_PROTOCOLLNPGM(" Classic PID ");
              SERIAL_PROTOCOLPGM(" Kp: "); SERIAL_PROTOCOLLN(_Kp);
              SERIAL_PROTOCOLPGM(" Ki: "); SERIAL_PROTOCOLLN(_Ki);
              SERIAL_PROTOCOLPGM(" Kd: "); SERIAL_PROTOCOLLN(_Kd);
              /*
              _Kp = 0.33*Ku;
              _Ki = _Kp/Tu;
              _Kd = _Kp*Tu/3;
              SERIAL_PROTOCOLLNPGM(" Some overshoot ");
              SERIAL_PROTOCOLPGM(" Kp: "); SERIAL_PROTOCOLLN(_Kp);
              SERIAL_PROTOCOLPGM(" Ki: "); SERIAL_PROTOCOLLN(_Ki);
              SERIAL_PROTOCOLPGM(" Kd: "); SERIAL_PROTOCOLLN(_Kd);
              _Kp = 0.2*Ku;
              _Ki = 2*_Kp/Tu;
              _Kd = _Kp*Tu/3;
              SERIAL_PROTOCOLLNPGM(" No overshoot ");
              SERIAL_PROTOCOLPGM(" Kp: "); SERIAL_PROTOCOLLN(_Kp);
              SERIAL_PROTOCOLPGM(" Ki: "); SERIAL_PROTOCOLLN(_Ki);
              SERIAL_PROTOCOLPGM(" Kd: "); SERIAL_PROTOCOLLN(_Kd);
              */
            }
          }
          if (extruder<0)
		  {
            soft_pwm_bed = (bias + d) >> 1;
			timer02_set_pwm0(soft_pwm_bed << 1);
		  }
          else
            soft_pwm[extruder] = (bias + d) >> 1;
          pid_cycle++;
          min=temp;
        }
      } 
    }
    if(input > (temp + 20)) {
      SERIAL_PROTOCOLLNPGM("PID Autotune failed! Temperature too high");
	  pid_tuning_finished = true;
	  pid_cycle = 0;
      return;
    }
    if(_millis() - temp_millis > 2000) {
      int p;
      if (extruder<0){
        p=soft_pwm_bed;       
        SERIAL_PROTOCOLPGM("B:");
      }else{
        p=soft_pwm[extruder];       
        SERIAL_PROTOCOLPGM("T:");
      }
			
      SERIAL_PROTOCOL(input);   
      SERIAL_PROTOCOLPGM(" @:");
      SERIAL_PROTOCOLLN(p);       
		if (safety_check_cycles == 0) { //save ambient temp
			temp_ambient = input;
			//SERIAL_ECHOPGM("Ambient T: ");
			//MYSERIAL.println(temp_ambient);
			safety_check_cycles++;
		}
		else if (safety_check_cycles < safety_check_cycles_count) { //delay
			safety_check_cycles++;		
		}
		else if (safety_check_cycles == safety_check_cycles_count){ //check that temperature is rising
			safety_check_cycles++;
			//SERIAL_ECHOPGM("Time from beginning: ");
			//MYSERIAL.print(safety_check_cycles_count * 2);
			//SERIAL_ECHOPGM("s. Difference between current and ambient T: ");
			//MYSERIAL.println(input - temp_ambient);

			if (fabs(input - temp_ambient) < 5.0) { 
				temp_runaway_stop(false, (extruder<0));
				pid_tuning_finished = true;
				return;
			}
		}
      temp_millis = _millis();
    }
    if(((_millis() - t1) + (_millis() - t2)) > (10L*60L*1000L*2L)) {
      SERIAL_PROTOCOLLNPGM("PID Autotune failed! timeout");
	  pid_tuning_finished = true;
	  pid_cycle = 0;
      return;
    }
    if(pid_cycle > ncycles) {
      SERIAL_PROTOCOLLNPGM("PID Autotune finished! Put the last Kp, Ki and Kd constants from above into Configuration.h");
	  pid_tuning_finished = true;
	  pid_cycle = 0;
      return;
    }
    lcd_update(0);
  }
}

void updatePID()
{
#ifdef PIDTEMP
  for(uint_least8_t e = 0; e < EXTRUDERS; e++) {
     iState_sum_max[e] = PID_INTEGRAL_DRIVE_MAX / cs.Ki;  
  }
#endif
#ifdef PIDTEMPBED
  temp_iState_max_bed = PID_INTEGRAL_DRIVE_MAX / cs.bedKi;  
#endif
}
  
int getHeaterPower(int heater) {
	if (heater<0)
		return soft_pwm_bed;
  return soft_pwm[heater];
}

#if (defined(EXTRUDER_0_AUTO_FAN_PIN) && EXTRUDER_0_AUTO_FAN_PIN > -1)

  #if defined(FAN_PIN) && FAN_PIN > -1
    #if EXTRUDER_0_AUTO_FAN_PIN == FAN_PIN 
       #error "You cannot set EXTRUDER_0_AUTO_FAN_PIN equal to FAN_PIN"
    #endif
  #endif

void setExtruderAutoFanState(uint8_t state)
{
	//If bit 1 is set (0x02), then the extruder fan speed won't be adjusted according to temperature. Useful for forcing
	//the fan to either On or Off during certain tests/errors.

	fanState = state;
	newFanSpeed = 0;
	if (fanState & 0x01)
	{
#ifdef EXTRUDER_ALTFAN_DETECT
		if (altfanStatus.isAltfan && !altfanStatus.altfanOverride) newFanSpeed = EXTRUDER_ALTFAN_SPEED_SILENT;
		else newFanSpeed = EXTRUDER_AUTO_FAN_SPEED;
#else //EXTRUDER_ALTFAN_DETECT
		newFanSpeed = EXTRUDER_AUTO_FAN_SPEED;
#endif //EXTRUDER_ALTFAN_DETECT
	}
	timer4_set_fan0(newFanSpeed);
}

#if (defined(FANCHECK) && (((defined(TACH_0) && (TACH_0 >-1)) || (defined(TACH_1) && (TACH_1 > -1)))))

void countFanSpeed()
{
	//SERIAL_ECHOPGM("edge counter 1:"); MYSERIAL.println(fan_edge_counter[1]);
	fan_speed[0] = (fan_edge_counter[0] * (float(250) / (_millis() - extruder_autofan_last_check)));
	fan_speed[1] = (fan_edge_counter[1] * (float(250) / (_millis() - extruder_autofan_last_check)));
	/*SERIAL_ECHOPGM("time interval: "); MYSERIAL.println(_millis() - extruder_autofan_last_check);
	SERIAL_ECHOPGM("extruder fan speed:"); MYSERIAL.print(fan_speed[0]); SERIAL_ECHOPGM("; edge counter:"); MYSERIAL.println(fan_edge_counter[0]);
	SERIAL_ECHOPGM("print fan speed:"); MYSERIAL.print(fan_speed[1]); SERIAL_ECHOPGM("; edge counter:"); MYSERIAL.println(fan_edge_counter[1]);
	SERIAL_ECHOLNPGM(" ");*/
	fan_edge_counter[0] = 0;
	fan_edge_counter[1] = 0;
}

void checkFanSpeed()
{
	uint8_t max_print_fan_errors = 0;
	uint8_t max_extruder_fan_errors = 0;
#ifdef FAN_SOFT_PWM
	max_print_fan_errors = 3; //15 seconds
	max_extruder_fan_errors = 2; //10seconds
#else //FAN_SOFT_PWM
	max_print_fan_errors = 15; //15 seconds
	max_extruder_fan_errors = 5; //5 seconds
#endif //FAN_SOFT_PWM
  
  if(fans_check_enabled != false)
	  fans_check_enabled = (eeprom_read_byte((uint8_t*)EEPROM_FAN_CHECK_ENABLED) > 0);
	static unsigned char fan_speed_errors[2] = { 0,0 };
#if (defined(FANCHECK) && defined(TACH_0) && (TACH_0 >-1))
	if ((fan_speed[0] < 20) && (current_temperature[0] > EXTRUDER_AUTO_FAN_TEMPERATURE)){ fan_speed_errors[0]++;}
	else fan_speed_errors[0] = 0;
#endif
#if (defined(FANCHECK) && defined(TACH_1) && (TACH_1 >-1))
	if ((fan_speed[1] < 5) && ((blocks_queued() ? block_buffer[block_buffer_tail].fan_speed : fanSpeed) > MIN_PRINT_FAN_SPEED)) fan_speed_errors[1]++;
	else fan_speed_errors[1] = 0;
#endif

	// drop the fan_check_error flag when both fans are ok
	if( fan_speed_errors[0] == 0 && fan_speed_errors[1] == 0 && fan_check_error == EFCE_REPORTED){
		// we may even send some info to the LCD from here
		fan_check_error = EFCE_FIXED;
	}
	if ((fan_check_error == EFCE_FIXED) && !PRINTER_ACTIVE){
		fan_check_error = EFCE_OK; //if the issue is fixed while the printer is doing nothing, reenable processing immediately.
		lcd_reset_alert_level(); //for another fan speed error
	}
	if ((fan_speed_errors[0] > max_extruder_fan_errors) && fans_check_enabled && (fan_check_error == EFCE_OK)) {
		fan_speed_errors[0] = 0;
		fanSpeedError(0); //extruder fan
	}
	if ((fan_speed_errors[1] > max_print_fan_errors) && fans_check_enabled && (fan_check_error == EFCE_OK)) {
		fan_speed_errors[1] = 0;
		fanSpeedError(1); //print fan
	}
}

//! Prints serialMsg to serial port, displays lcdMsg onto the LCD and beeps.
//! Extracted from fanSpeedError to save some space.
//! @param serialMsg pointer into PROGMEM, this text will be printed to the serial port
//! @param lcdMsg pointer into PROGMEM, this text will be printed onto the LCD
static void fanSpeedErrorBeep(const char *serialMsg, const char *lcdMsg){
	SERIAL_ECHOLNRPGM(serialMsg);
	if (get_message_level() == 0) {
		Sound_MakeCustom(200,0,true);
		LCD_ALERTMESSAGERPGM(lcdMsg);
	}
}

void fanSpeedError(unsigned char _fan) {
	if (get_message_level() != 0 && isPrintPaused) return;
	//to ensure that target temp. is not set to zero in case that we are resuming print
	if (card.sdprinting || usb_timer.running()) {
		if (heating_status != HeatingStatus::NO_HEATING) {
			lcd_print_stop();
		}
		else {
			fan_check_error = EFCE_DETECTED; //plans error for next processed command
		}
	}
	else {
		// SERIAL_PROTOCOLLNRPGM(MSG_OCTOPRINT_PAUSED); //Why pause octoprint? usb_timer.running() would be true in that case, so there is no need for this.
		setTargetHotend0(0);
        heating_status = HeatingStatus::NO_HEATING;
        fan_check_error = EFCE_REPORTED;
	}
	switch (_fan) {
	case 0:	// extracting the same code from case 0 and case 1 into a function saves 72B
		fanSpeedErrorBeep(PSTR("Extruder fan speed is lower than expected"), MSG_FANCHECK_EXTRUDER);
		break;
	case 1:
		fanSpeedErrorBeep(PSTR("Print fan speed is lower than expected"), MSG_FANCHECK_PRINT);
		break;
	}
}
#endif //(defined(TACH_0) && TACH_0 >-1) || (defined(TACH_1) && TACH_1 > -1)


void checkExtruderAutoFans()
{
#if defined(EXTRUDER_0_AUTO_FAN_PIN) && EXTRUDER_0_AUTO_FAN_PIN > -1
	if (!(fanState & 0x02))
	{
		fanState &= ~1;
		fanState |= current_temperature[0] > EXTRUDER_AUTO_FAN_TEMPERATURE;
	}
	setExtruderAutoFanState(fanState);
#endif 
}

#endif // any extruder auto fan pins set

// ready for eventually parameters adjusting
void resetPID(uint8_t)                            // only for compiler-warning elimination (if function do nothing)
//void resetPID(uint8_t extruder)
{
}

void manage_heater()
{
#ifdef WATCHDOG
    wdt_reset();
#endif //WATCHDOG

  float pid_input;
  float pid_output;

  if(temp_meas_ready != true)   //better readability
    return; 
// more precisely - this condition partially stabilizes time interval for regulation values evaluation (@ ~ 230ms)

  // ADC values need to be converted before checking: converted values are later used in MINTEMP
  updateTemperaturesFromRawValues();

  check_max_temp();
  check_min_temp();

#ifdef TEMP_RUNAWAY_BED_HYSTERESIS
  temp_runaway_check(0, target_temperature_bed, current_temperature_bed, (int)soft_pwm_bed, true);
#endif

  for(uint8_t e = 0; e < EXTRUDERS; e++) 
  {

#ifdef TEMP_RUNAWAY_EXTRUDER_HYSTERESIS
	  temp_runaway_check(e+1, target_temperature[e], current_temperature[e], (int)soft_pwm[e], false);
#endif

  #ifdef PIDTEMP
    pid_input = current_temperature[e];

    #ifndef PID_OPENLOOP
        if(target_temperature[e] == 0) {
          pid_output = 0;
          pid_reset[e] = true;
        } else {
          pid_error[e] = target_temperature[e] - pid_input;
          if(pid_reset[e]) {
            iState_sum[e] = 0.0;
            dTerm[e] = 0.0;                       // 'dState_last[e]' initial setting is not necessary (see end of if-statement)
            pid_reset[e] = false;
          }
#ifndef PonM
          pTerm[e] = cs.Kp * pid_error[e];
          iState_sum[e] += pid_error[e];
          iState_sum[e] = constrain(iState_sum[e], iState_sum_min[e], iState_sum_max[e]);
          iTerm[e] = cs.Ki * iState_sum[e];
          // PID_K1 defined in Configuration.h in the PID settings
          #define K2 (1.0-PID_K1)
          dTerm[e] = (cs.Kd * (pid_input - dState_last[e]))*K2 + (PID_K1 * dTerm[e]); // e.g. digital filtration of derivative term changes
          pid_output = pTerm[e] + iTerm[e] - dTerm[e]; // subtraction due to "Derivative on Measurement" method (i.e. derivative of input instead derivative of error is used)
          if (pid_output > PID_MAX) {
            if (pid_error[e] > 0 ) iState_sum[e] -= pid_error[e]; // conditional un-integration
            pid_output=PID_MAX;
          } else if (pid_output < 0) {
            if (pid_error[e] < 0 ) iState_sum[e] -= pid_error[e]; // conditional un-integration
            pid_output=0;
          }
#else // PonM ("Proportional on Measurement" method)
          iState_sum[e] += cs.Ki * pid_error[e];
          iState_sum[e] -= cs.Kp * (pid_input - dState_last[e]);
          iState_sum[e] = constrain(iState_sum[e], 0, PID_INTEGRAL_DRIVE_MAX);
          dTerm[e] = cs.Kd * (pid_input - dState_last[e]);
          pid_output = iState_sum[e] - dTerm[e];  // subtraction due to "Derivative on Measurement" method (i.e. derivative of input instead derivative of error is used)
          pid_output = constrain(pid_output, 0, PID_MAX);
#endif // PonM
        }
        dState_last[e] = pid_input;
    #else 
          pid_output = constrain(target_temperature[e], 0, PID_MAX);
    #endif //PID_OPENLOOP
    #ifdef PID_DEBUG
    SERIAL_ECHO_START;
    SERIAL_ECHO(" PID_DEBUG ");
    SERIAL_ECHO(e);
    SERIAL_ECHO(": Input ");
    SERIAL_ECHO(pid_input);
    SERIAL_ECHO(" Output ");
    SERIAL_ECHO(pid_output);
    SERIAL_ECHO(" pTerm ");
    SERIAL_ECHO(pTerm[e]);
    SERIAL_ECHO(" iTerm ");
    SERIAL_ECHO(iTerm[e]);
    SERIAL_ECHO(" dTerm ");
    SERIAL_ECHOLN(-dTerm[e]);
    #endif //PID_DEBUG
  #else /* PID off */
    pid_output = 0;
    if(current_temperature[e] < target_temperature[e]) {
      pid_output = PID_MAX;
    }
  #endif

    // Check if temperature is within the correct range
    if((current_temperature[e] < maxttemp[e]) && (target_temperature[e] != 0))
    {
      soft_pwm[e] = (int)pid_output >> 1;
    }
    else
    {
      soft_pwm[e] = 0;
    }
  } // End extruder for loop

#define FAN_CHECK_PERIOD 5000 //5s
#define FAN_CHECK_DURATION 100 //100ms

#ifndef DEBUG_DISABLE_FANCHECK
  #if (defined(EXTRUDER_0_AUTO_FAN_PIN) && EXTRUDER_0_AUTO_FAN_PIN > -1)

#ifdef FAN_SOFT_PWM
#ifdef FANCHECK
  if ((_millis() - extruder_autofan_last_check > FAN_CHECK_PERIOD) && (!fan_measuring)) {
	  extruder_autofan_last_check = _millis();
	  fanSpeedBckp = fanSpeedSoftPwm;
	  
	  if (fanSpeedSoftPwm >= MIN_PRINT_FAN_SPEED) { //if we are in rage where we are doing fan check, set full PWM range for a short time to measure fan RPM by reading tacho signal without modulation by PWM signal
		//  printf_P(PSTR("fanSpeedSoftPwm 1: %d\n"), fanSpeedSoftPwm);
		  fanSpeedSoftPwm = 255;
	  }
	  fan_measuring = true;
  }
  if ((_millis() - extruder_autofan_last_check > FAN_CHECK_DURATION) && (fan_measuring)) {
	  countFanSpeed();
	  checkFanSpeed();
	  //printf_P(PSTR("fanSpeedSoftPwm 1: %d\n"), fanSpeedSoftPwm);
	  fanSpeedSoftPwm = fanSpeedBckp;
	  //printf_P(PSTR("fan PWM: %d; extr fanSpeed measured: %d; print fan speed measured: %d \n"), fanSpeedBckp, fan_speed[0], fan_speed[1]);
	  extruder_autofan_last_check = _millis();
	  fan_measuring = false;
  }
#endif //FANCHECK
  checkExtruderAutoFans();
#else //FAN_SOFT_PWM
  if(_millis() - extruder_autofan_last_check > 1000)  // only need to check fan state very infrequently
  {
#if (defined(FANCHECK) && ((defined(TACH_0) && (TACH_0 >-1)) || (defined(TACH_1) && (TACH_1 > -1))))
	countFanSpeed();
	checkFanSpeed();
#endif //(defined(TACH_0) && TACH_0 >-1) || (defined(TACH_1) && TACH_1 > -1)
    checkExtruderAutoFans();
    extruder_autofan_last_check = _millis();
  }  
#endif //FAN_SOFT_PWM

  #endif  
#endif //DEBUG_DISABLE_FANCHECK
  
  #ifndef PIDTEMPBED
  if(_millis() - previous_millis_bed_heater < BED_CHECK_INTERVAL)
    return;
  previous_millis_bed_heater = _millis();
  #endif

  #if TEMP_SENSOR_BED != 0

  #ifdef PIDTEMPBED
    pid_input = current_temperature_bed;

    #ifndef PID_OPENLOOP
		  pid_error_bed = target_temperature_bed - pid_input;
		  pTerm_bed = cs.bedKp * pid_error_bed;
		  temp_iState_bed += pid_error_bed;
		  temp_iState_bed = constrain(temp_iState_bed, temp_iState_min_bed, temp_iState_max_bed);
		  iTerm_bed = cs.bedKi * temp_iState_bed;

		  //PID_K1 defined in Configuration.h in the PID settings
		  #define K2 (1.0-PID_K1)
		  dTerm_bed= (cs.bedKd * (pid_input - temp_dState_bed))*K2 + (PID_K1 * dTerm_bed);
		  temp_dState_bed = pid_input;

		  pid_output = pTerm_bed + iTerm_bed - dTerm_bed;
          	  if (pid_output > MAX_BED_POWER) {
            	    if (pid_error_bed > 0 )  temp_iState_bed -= pid_error_bed; // conditional un-integration
                    pid_output=MAX_BED_POWER;
          	  } else if (pid_output < 0){
            	    if (pid_error_bed < 0 )  temp_iState_bed -= pid_error_bed; // conditional un-integration
                    pid_output=0;
                  }

    #else 
      pid_output = constrain(target_temperature_bed, 0, MAX_BED_POWER);
    #endif //PID_OPENLOOP

	  if(current_temperature_bed < BED_MAXTEMP)
	  {
	    soft_pwm_bed = (int)pid_output >> 1;
		timer02_set_pwm0(soft_pwm_bed << 1);
	  }
	  else {
	    soft_pwm_bed = 0;
		timer02_set_pwm0(soft_pwm_bed << 1);
	  }

    #elif !defined(BED_LIMIT_SWITCHING)
      // Check if temperature is within the correct range
      if(current_temperature_bed < BED_MAXTEMP)
      {
        if(current_temperature_bed >= target_temperature_bed)
        {
          soft_pwm_bed = 0;
		  timer02_set_pwm0(soft_pwm_bed << 1);
        }
        else 
        {
          soft_pwm_bed = MAX_BED_POWER>>1;
		  timer02_set_pwm0(soft_pwm_bed << 1);
        }
      }
      else
      {
        soft_pwm_bed = 0;
		timer02_set_pwm0(soft_pwm_bed << 1);
        WRITE(HEATER_BED_PIN,LOW);
      }
    #else //#ifdef BED_LIMIT_SWITCHING
      // Check if temperature is within the correct band
      if(current_temperature_bed < BED_MAXTEMP)
      {
        if(current_temperature_bed > target_temperature_bed + BED_HYSTERESIS)
        {
          soft_pwm_bed = 0;
		  timer02_set_pwm0(soft_pwm_bed << 1);
        }
        else if(current_temperature_bed <= target_temperature_bed - BED_HYSTERESIS)
        {
          soft_pwm_bed = MAX_BED_POWER>>1;
          timer02_set_pwm0(soft_pwm_bed << 1);
        }
      }
      else
      {
        soft_pwm_bed = 0;
		timer02_set_pwm0(soft_pwm_bed << 1);
        WRITE(HEATER_BED_PIN,LOW);
      }
    #endif
      if(target_temperature_bed==0)
	  {
        soft_pwm_bed = 0;
		timer02_set_pwm0(soft_pwm_bed << 1);
	  }
  #endif
}

#define PGM_RD_W(x)   (short)pgm_read_word(&x)
// Derived from RepRap FiveD extruder::getTemperature()
// For hot end temperature measurement.
static float analog2temp(int raw, uint8_t e) {
  if(e >= EXTRUDERS)
  {
      SERIAL_ERROR_START;
      SERIAL_ERROR((int)e);
      SERIAL_ERRORLNPGM(" - Invalid extruder number !");
      kill(NULL, 6);
      return 0.0;
  } 
  #ifdef HEATER_0_USES_MAX6675
    if (e == 0)
    {
      return 0.25 * raw;
    }
  #endif

  if(heater_ttbl_map[e] != NULL)
  {
    float celsius = 0;
    uint8_t i;
    short (*tt)[][2] = (short (*)[][2])(heater_ttbl_map[e]);

    for (i=1; i<heater_ttbllen_map[e]; i++)
    {
      if (PGM_RD_W((*tt)[i][0]) > raw)
      {
        celsius = PGM_RD_W((*tt)[i-1][1]) + 
          (raw - PGM_RD_W((*tt)[i-1][0])) * 
          (float)(PGM_RD_W((*tt)[i][1]) - PGM_RD_W((*tt)[i-1][1])) /
          (float)(PGM_RD_W((*tt)[i][0]) - PGM_RD_W((*tt)[i-1][0]));
        break;
      }
    }

    // Overflow: Set to last value in the table
    if (i == heater_ttbllen_map[e]) celsius = PGM_RD_W((*tt)[i-1][1]);

    return celsius;
  }
  return ((raw * ((5.0 * 100.0) / 1024.0) / OVERSAMPLENR) * TEMP_SENSOR_AD595_GAIN) + TEMP_SENSOR_AD595_OFFSET;
}

// Derived from RepRap FiveD extruder::getTemperature()
// For bed temperature measurement.
static float analog2tempBed(int raw) {
  #ifdef BED_USES_THERMISTOR
    float celsius = 0;
    byte i;

    for (i=1; i<BEDTEMPTABLE_LEN; i++)
    {
      if (PGM_RD_W(BEDTEMPTABLE[i][0]) > raw)
      {
        celsius  = PGM_RD_W(BEDTEMPTABLE[i-1][1]) + 
          (raw - PGM_RD_W(BEDTEMPTABLE[i-1][0])) * 
          (float)(PGM_RD_W(BEDTEMPTABLE[i][1]) - PGM_RD_W(BEDTEMPTABLE[i-1][1])) /
          (float)(PGM_RD_W(BEDTEMPTABLE[i][0]) - PGM_RD_W(BEDTEMPTABLE[i-1][0]));
        break;
      }
    }

    // Overflow: Set to last value in the table
    if (i == BEDTEMPTABLE_LEN) celsius = PGM_RD_W(BEDTEMPTABLE[i-1][1]);


	// temperature offset adjustment
#ifdef BED_OFFSET
	float _offset = BED_OFFSET;
	float _offset_center = BED_OFFSET_CENTER;
	float _offset_start = BED_OFFSET_START;
	float _first_koef = (_offset / 2) / (_offset_center - _offset_start);
	float _second_koef = (_offset / 2) / (100 - _offset_center);


	if (celsius >= _offset_start && celsius <= _offset_center)
	{
		celsius = celsius + (_first_koef * (celsius - _offset_start));
	}
	else if (celsius > _offset_center && celsius <= 100)
	{
		celsius = celsius + (_first_koef * (_offset_center - _offset_start)) + ( _second_koef * ( celsius - ( 100 - _offset_center ) )) ;
	}
	else if (celsius > 100)
	{
		celsius = celsius + _offset;
	}
#endif


    return celsius;
  #elif defined BED_USES_AD595
    return ((raw * ((5.0 * 100.0) / 1024.0) / OVERSAMPLENR) * TEMP_SENSOR_AD595_GAIN) + TEMP_SENSOR_AD595_OFFSET;
  #else
    return 0;
  #endif
}

#ifdef AMBIENT_THERMISTOR
static float analog2tempAmbient(int raw)
{
    float celsius = 0;
    byte i;

    for (i=1; i<AMBIENTTEMPTABLE_LEN; i++)
    {
      if (PGM_RD_W(AMBIENTTEMPTABLE[i][0]) > raw)
      {
        celsius  = PGM_RD_W(AMBIENTTEMPTABLE[i-1][1]) + 
          (raw - PGM_RD_W(AMBIENTTEMPTABLE[i-1][0])) * 
          (float)(PGM_RD_W(AMBIENTTEMPTABLE[i][1]) - PGM_RD_W(AMBIENTTEMPTABLE[i-1][1])) /
          (float)(PGM_RD_W(AMBIENTTEMPTABLE[i][0]) - PGM_RD_W(AMBIENTTEMPTABLE[i-1][0]));
        break;
      }
    }
    // Overflow: Set to last value in the table
    if (i == AMBIENTTEMPTABLE_LEN) celsius = PGM_RD_W(AMBIENTTEMPTABLE[i-1][1]);
    return celsius;
}
#endif //AMBIENT_THERMISTOR

/* Called to get the raw values into the the actual temperatures. The raw values are created in interrupt context,
    and this function is called from normal context as it is too slow to run in interrupts and will block the stepper routine otherwise */
static void updateTemperaturesFromRawValues()
{
    for(uint8_t e=0;e<EXTRUDERS;e++)
    {
        current_temperature[e] = analog2temp(current_temperature_raw[e], e);
    }

#ifdef PINDA_THERMISTOR
	current_temperature_raw_pinda = (uint16_t)((uint32_t)current_temperature_raw_pinda * 3 + current_temperature_raw_pinda_fast) >> 2;
	current_temperature_pinda = analog2tempBed(current_temperature_raw_pinda);
#endif

#ifdef AMBIENT_THERMISTOR
	current_temperature_ambient = analog2tempAmbient(current_temperature_raw_ambient); //thermistor for ambient is NTCG104LH104JT1 (2000)
#endif
   
#ifdef DEBUG_HEATER_BED_SIM
	current_temperature_bed = target_temperature_bed;
#else //DEBUG_HEATER_BED_SIM
	current_temperature_bed = analog2tempBed(current_temperature_bed_raw);
#endif //DEBUG_HEATER_BED_SIM

    CRITICAL_SECTION_START;
    temp_meas_ready = false;
    CRITICAL_SECTION_END;
}

void tp_init()
{
#if MB(RUMBA) && ((TEMP_SENSOR_0==-1)||(TEMP_SENSOR_1==-1)||(TEMP_SENSOR_2==-1)||(TEMP_SENSOR_BED==-1))
  //disable RUMBA JTAG in case the thermocouple extension is plugged on top of JTAG connector
  MCUCR=(1<<JTD); 
  MCUCR=(1<<JTD);
#endif
  
  // Finish init of mult extruder arrays 
  for(int e = 0; e < EXTRUDERS; e++) {
    // populate with the first value 
    maxttemp[e] = maxttemp[0];
#ifdef PIDTEMP
    iState_sum_min[e] = 0.0;
    iState_sum_max[e] = PID_INTEGRAL_DRIVE_MAX / cs.Ki;
#endif //PIDTEMP
#ifdef PIDTEMPBED
    temp_iState_min_bed = 0.0;
    temp_iState_max_bed = PID_INTEGRAL_DRIVE_MAX / cs.bedKi;
#endif //PIDTEMPBED
  }

  #if defined(HEATER_0_PIN) && (HEATER_0_PIN > -1) 
    SET_OUTPUT(HEATER_0_PIN);
  #endif  
  #if defined(HEATER_1_PIN) && (HEATER_1_PIN > -1) 
    SET_OUTPUT(HEATER_1_PIN);
  #endif  
  #if defined(HEATER_2_PIN) && (HEATER_2_PIN > -1) 
    SET_OUTPUT(HEATER_2_PIN);
  #endif  
  #if defined(HEATER_BED_PIN) && (HEATER_BED_PIN > -1) 
    SET_OUTPUT(HEATER_BED_PIN);
  #endif  
  #if defined(FAN_PIN) && (FAN_PIN > -1) 
    SET_OUTPUT(FAN_PIN);
    #ifdef FAST_PWM_FAN
    setPwmFrequency(FAN_PIN, 1); // No prescaling. Pwm frequency = F_CPU/256/8
    #endif
    #ifdef FAN_SOFT_PWM
    soft_pwm_fan = fanSpeedSoftPwm / (1 << (8 - FAN_SOFT_PWM_BITS));
    #endif
  #endif

  #ifdef HEATER_0_USES_MAX6675
    #ifndef SDSUPPORT
      SET_OUTPUT(SCK_PIN);
      WRITE(SCK_PIN,0);
    
      SET_OUTPUT(MOSI_PIN);
      WRITE(MOSI_PIN,1);
    
      SET_INPUT(MISO_PIN);
      WRITE(MISO_PIN,1);
    #endif
    /* Using pinMode and digitalWrite, as that was the only way I could get it to compile */
    
    //Have to toggle SD card CS pin to low first, to enable firmware to talk with SD card
	pinMode(SS_PIN, OUTPUT);
	digitalWrite(SS_PIN,0);  
	pinMode(MAX6675_SS, OUTPUT);
	digitalWrite(MAX6675_SS,1);
  #endif

  adc_init();

  timer0_init(); //enables the heatbed timer.

  // timer2 already enabled earlier in the code
  // now enable the COMPB temperature interrupt
  OCR2B = 128;
  TIMSK2 |= (1<<OCIE2B);
  
  timer4_init(); //for tone and Extruder fan PWM
  
  // Wait for temperature measurement to settle
  _delay(250);

#ifdef HEATER_0_MINTEMP
  minttemp[0] = HEATER_0_MINTEMP;
  while(analog2temp(minttemp_raw[0], 0) < HEATER_0_MINTEMP) {
#if HEATER_0_RAW_LO_TEMP < HEATER_0_RAW_HI_TEMP
    minttemp_raw[0] += OVERSAMPLENR;
#else
    minttemp_raw[0] -= OVERSAMPLENR;
#endif
  }
#endif //MINTEMP
#ifdef HEATER_0_MAXTEMP
  maxttemp[0] = HEATER_0_MAXTEMP;
  while(analog2temp(maxttemp_raw[0], 0) > HEATER_0_MAXTEMP) {
#if HEATER_0_RAW_LO_TEMP < HEATER_0_RAW_HI_TEMP
    maxttemp_raw[0] -= OVERSAMPLENR;
#else
    maxttemp_raw[0] += OVERSAMPLENR;
#endif
  }
#endif //MAXTEMP

#if (EXTRUDERS > 1) && defined(HEATER_1_MINTEMP)
  minttemp[1] = HEATER_1_MINTEMP;
  while(analog2temp(minttemp_raw[1], 1) < HEATER_1_MINTEMP) {
#if HEATER_1_RAW_LO_TEMP < HEATER_1_RAW_HI_TEMP
    minttemp_raw[1] += OVERSAMPLENR;
#else
    minttemp_raw[1] -= OVERSAMPLENR;
#endif
  }
#endif // MINTEMP 1
#if (EXTRUDERS > 1) && defined(HEATER_1_MAXTEMP)
  maxttemp[1] = HEATER_1_MAXTEMP;
  while(analog2temp(maxttemp_raw[1], 1) > HEATER_1_MAXTEMP) {
#if HEATER_1_RAW_LO_TEMP < HEATER_1_RAW_HI_TEMP
    maxttemp_raw[1] -= OVERSAMPLENR;
#else
    maxttemp_raw[1] += OVERSAMPLENR;
#endif
  }
#endif //MAXTEMP 1

#if (EXTRUDERS > 2) && defined(HEATER_2_MINTEMP)
  minttemp[2] = HEATER_2_MINTEMP;
  while(analog2temp(minttemp_raw[2], 2) < HEATER_2_MINTEMP) {
#if HEATER_2_RAW_LO_TEMP < HEATER_2_RAW_HI_TEMP
    minttemp_raw[2] += OVERSAMPLENR;
#else
    minttemp_raw[2] -= OVERSAMPLENR;
#endif
  }
#endif //MINTEMP 2
#if (EXTRUDERS > 2) && defined(HEATER_2_MAXTEMP)
  maxttemp[2] = HEATER_2_MAXTEMP;
  while(analog2temp(maxttemp_raw[2], 2) > HEATER_2_MAXTEMP) {
#if HEATER_2_RAW_LO_TEMP < HEATER_2_RAW_HI_TEMP
    maxttemp_raw[2] -= OVERSAMPLENR;
#else
    maxttemp_raw[2] += OVERSAMPLENR;
#endif
  }
#endif //MAXTEMP 2

#ifdef BED_MINTEMP
  while(analog2tempBed(bed_minttemp_raw) < BED_MINTEMP) {
#if HEATER_BED_RAW_LO_TEMP < HEATER_BED_RAW_HI_TEMP
    bed_minttemp_raw += OVERSAMPLENR;
#else
    bed_minttemp_raw -= OVERSAMPLENR;
#endif
  }
#endif //BED_MINTEMP
#ifdef BED_MAXTEMP
  while(analog2tempBed(bed_maxttemp_raw) > BED_MAXTEMP) {
#if HEATER_BED_RAW_LO_TEMP < HEATER_BED_RAW_HI_TEMP
    bed_maxttemp_raw -= OVERSAMPLENR;
#else
    bed_maxttemp_raw += OVERSAMPLENR;
#endif
  }
#endif //BED_MAXTEMP

#ifdef AMBIENT_MINTEMP
  while(analog2tempAmbient(ambient_minttemp_raw) < AMBIENT_MINTEMP) {
#if HEATER_AMBIENT_RAW_LO_TEMP < HEATER_AMBIENT_RAW_HI_TEMP
    ambient_minttemp_raw += OVERSAMPLENR;
#else
    ambient_minttemp_raw -= OVERSAMPLENR;
#endif
  }
#endif //AMBIENT_MINTEMP
#ifdef AMBIENT_MAXTEMP
  while(analog2tempAmbient(ambient_maxttemp_raw) > AMBIENT_MAXTEMP) {
#if HEATER_AMBIENT_RAW_LO_TEMP < HEATER_AMBIENT_RAW_HI_TEMP
    ambient_maxttemp_raw -= OVERSAMPLENR;
#else
    ambient_maxttemp_raw += OVERSAMPLENR;
#endif
  }
#endif //AMBIENT_MAXTEMP
}

#if (defined (TEMP_RUNAWAY_BED_HYSTERESIS) && TEMP_RUNAWAY_BED_TIMEOUT > 0) || (defined (TEMP_RUNAWAY_EXTRUDER_HYSTERESIS) && TEMP_RUNAWAY_EXTRUDER_TIMEOUT > 0)
void temp_runaway_check(uint8_t _heater_id, float _target_temperature, float _current_temperature, float _output, bool _isbed)
{
     float __delta;
	float __hysteresis = 0;
	uint16_t __timeout = 0;
	bool temp_runaway_check_active = false;
	static float __preheat_start[2] = { 0,0}; //currently just bed and one extruder
	static uint8_t __preheat_counter[2] = { 0,0};
	static uint8_t __preheat_errors[2] = { 0,0};
		

	if (_millis() - temp_runaway_timer[_heater_id] > 2000)
	{

#ifdef 	TEMP_RUNAWAY_BED_TIMEOUT
          if (_isbed)
          {
               __hysteresis = TEMP_RUNAWAY_BED_HYSTERESIS;
               __timeout = TEMP_RUNAWAY_BED_TIMEOUT;
          }
#endif
#ifdef 	TEMP_RUNAWAY_EXTRUDER_TIMEOUT
          if (!_isbed)
          {
               __hysteresis = TEMP_RUNAWAY_EXTRUDER_HYSTERESIS;
               __timeout = TEMP_RUNAWAY_EXTRUDER_TIMEOUT;
          }
#endif

		temp_runaway_timer[_heater_id] = _millis();
		if (_output == 0)
		{
			temp_runaway_check_active = false;
			temp_runaway_error_counter[_heater_id] = 0;
		}

		if (temp_runaway_target[_heater_id] != _target_temperature)
		{
			if (_target_temperature > 0)
			{
				temp_runaway_status[_heater_id] = TempRunaway_PREHEAT;
				temp_runaway_target[_heater_id] = _target_temperature;
				__preheat_start[_heater_id] = _current_temperature;
				__preheat_counter[_heater_id] = 0;
			}
			else
			{
				temp_runaway_status[_heater_id] = TempRunaway_INACTIVE;
				temp_runaway_target[_heater_id] = _target_temperature;
			}
		}

		if ((_current_temperature < _target_temperature)  && (temp_runaway_status[_heater_id] == TempRunaway_PREHEAT))
		{
			__preheat_counter[_heater_id]++;
			if (__preheat_counter[_heater_id] > ((_isbed) ? 16 : 8)) // periodicaly check if current temperature changes
			{
				/*SERIAL_ECHOPGM("Heater:");
				MYSERIAL.print(_heater_id);
				SERIAL_ECHOPGM(" T:");
				MYSERIAL.print(_current_temperature);
				SERIAL_ECHOPGM(" Tstart:");
				MYSERIAL.print(__preheat_start[_heater_id]);
				SERIAL_ECHOPGM(" delta:");
				MYSERIAL.print(_current_temperature-__preheat_start[_heater_id]);*/
				
//-//				if (_current_temperature - __preheat_start[_heater_id] < 2) {
//-//				if (_current_temperature - __preheat_start[_heater_id] < ((_isbed && (_current_temperature>105.0))?0.6:2.0)) {
                    __delta=2.0;
                    if(_isbed)
                         {
                         __delta=3.0;
                         if(_current_temperature>90.0) __delta=2.0;
                         if(_current_temperature>105.0) __delta=0.6;
                         }
				if (_current_temperature - __preheat_start[_heater_id] < __delta) {
					__preheat_errors[_heater_id]++;
					/*SERIAL_ECHOPGM(" Preheat errors:");
					MYSERIAL.println(__preheat_errors[_heater_id]);*/
				}
				else {
					//SERIAL_ECHOLNPGM("");
					__preheat_errors[_heater_id] = 0;
				}

				if (__preheat_errors[_heater_id] > ((_isbed) ? 3 : 5)) 
				{
					if (farm_mode) { prusa_statistics(0); }
					temp_runaway_stop(true, _isbed);
					if (farm_mode) { prusa_statistics(91); }
				}
				__preheat_start[_heater_id] = _current_temperature;
				__preheat_counter[_heater_id] = 0;
			}
		}

//-//		if (_current_temperature >= _target_temperature  && temp_runaway_status[_heater_id] == TempRunaway_PREHEAT)
		if ((_current_temperature > (_target_temperature - __hysteresis))  && temp_runaway_status[_heater_id] == TempRunaway_PREHEAT)
		{
			/*SERIAL_ECHOPGM("Heater:");
			MYSERIAL.print(_heater_id);
			MYSERIAL.println(" ->tempRunaway");*/
			temp_runaway_status[_heater_id] = TempRunaway_ACTIVE;
			temp_runaway_check_active = false;
			temp_runaway_error_counter[_heater_id] = 0;
		}

		if (_output > 0)
		{
			temp_runaway_check_active = true;
		}


		if (temp_runaway_check_active)
		{			
			//	we are in range
			if ((_current_temperature > (_target_temperature - __hysteresis)) && (_current_temperature < (_target_temperature + __hysteresis)))
			{
				temp_runaway_check_active = false;
				temp_runaway_error_counter[_heater_id] = 0;
			}
			else
			{
				if (temp_runaway_status[_heater_id] > TempRunaway_PREHEAT)
				{
					temp_runaway_error_counter[_heater_id]++;
					if (temp_runaway_error_counter[_heater_id] * 2 > __timeout)
					{
						if (farm_mode) { prusa_statistics(0); }
						temp_runaway_stop(false, _isbed);
						if (farm_mode) { prusa_statistics(90); }
					}
				}
			}
		}

	}
}

void temp_runaway_stop(bool isPreheat, bool isBed)
{
    disable_heater();
    Sound_MakeCustom(200,0,true);

    if (isPreheat)
	{
		lcd_setalertstatuspgm(isBed? PSTR("BED PREHEAT ERROR") : PSTR("PREHEAT ERROR"), LCD_STATUS_CRITICAL);
		SERIAL_ERROR_START;
		isBed ? SERIAL_ERRORLNPGM(" THERMAL RUNAWAY (PREHEAT HEATBED)") : SERIAL_ERRORLNPGM(" THERMAL RUNAWAY (PREHEAT HOTEND)");

#ifdef EXTRUDER_ALTFAN_DETECT
		altfanStatus.altfanOverride = 1; //full speed
#endif //EXTRUDER_ALTFAN_DETECT
		setExtruderAutoFanState(3);
		SET_OUTPUT(FAN_PIN);
#ifdef FAN_SOFT_PWM
		fanSpeedSoftPwm = 255;
#else //FAN_SOFT_PWM
		analogWrite(FAN_PIN, 255);
#endif //FAN_SOFT_PWM
		fanSpeed = 255;
	}
	else
	{
		lcd_setalertstatuspgm(isBed? PSTR("BED THERMAL RUNAWAY") : PSTR("THERMAL RUNAWAY"), LCD_STATUS_CRITICAL);
		SERIAL_ERROR_START;
		isBed ? SERIAL_ERRORLNPGM(" HEATBED THERMAL RUNAWAY") : SERIAL_ERRORLNPGM(" HOTEND THERMAL RUNAWAY");
	}

    Stop();
}
#endif


void disable_heater()
{
  setAllTargetHotends(0);
  setTargetBed(0);
  #if defined(TEMP_0_PIN) && TEMP_0_PIN > -1
  target_temperature[0]=0;
  soft_pwm[0]=0;
   #if defined(HEATER_0_PIN) && HEATER_0_PIN > -1  
     WRITE(HEATER_0_PIN,LOW);
   #endif
  #endif
     
  #if defined(TEMP_1_PIN) && TEMP_1_PIN > -1 && EXTRUDERS > 1
    target_temperature[1]=0;
    soft_pwm[1]=0;
    #if defined(HEATER_1_PIN) && HEATER_1_PIN > -1 
      WRITE(HEATER_1_PIN,LOW);
    #endif
  #endif
      
  #if defined(TEMP_2_PIN) && TEMP_2_PIN > -1 && EXTRUDERS > 2
    target_temperature[2]=0;
    soft_pwm[2]=0;
    #if defined(HEATER_2_PIN) && HEATER_2_PIN > -1  
      WRITE(HEATER_2_PIN,LOW);
    #endif
  #endif 

  #if defined(TEMP_BED_PIN) && TEMP_BED_PIN > -1
    target_temperature_bed=0;
    soft_pwm_bed=0;
	timer02_set_pwm0(soft_pwm_bed << 1);
	bedPWMDisabled = 0;
    #if defined(HEATER_BED_PIN) && HEATER_BED_PIN > -1
      //WRITE(HEATER_BED_PIN,LOW);
    #endif
  #endif 
}
//! codes of alert messages for the LCD - it is shorter to compare an uin8_t
//! than raw const char * of the messages themselves.
//! Could be used for MAXTEMP situations too - after reaching MAXTEMP and turning off the heater automagically
//! the heater/bed may cool down and a similar alert message like "MAXTERM fixed..." may be displayed.
enum { LCDALERT_NONE = 0, LCDALERT_HEATERMINTEMP, LCDALERT_BEDMINTEMP, LCDALERT_MINTEMPFIXED, LCDALERT_PLEASERESTART };

//! remember the last alert message sent to the LCD
//! to prevent flicker and improve speed
uint8_t last_alert_sent_to_lcd = LCDALERT_NONE;


//! update the current temperature error message
//! @param type short error abbreviation (PROGMEM)
void temp_update_messagepgm(const char* PROGMEM type)
{
    char msg[LCD_WIDTH];
    strcpy_P(msg, PSTR("Err: "));
    strcat_P(msg, type);
    lcd_setalertstatus(msg, LCD_STATUS_CRITICAL);
}

//! signal a temperature error on both the lcd and serial
//! @param type short error abbreviation (PROGMEM)
//! @param e optional extruder index for hotend errors
void temp_error_messagepgm(const char* PROGMEM type, uint8_t e = EXTRUDERS)
{
    temp_update_messagepgm(type);

    SERIAL_ERROR_START;

    if(e != EXTRUDERS) {
        SERIAL_ERROR((int)e);
        SERIAL_ERRORPGM(": ");
    }

    SERIAL_ERRORPGM("Heaters switched off. ");
    SERIAL_ERRORRPGM(type);
    SERIAL_ERRORLNPGM(" triggered!");
}


void max_temp_error(uint8_t e) {
  disable_heater();
  if(IsStopped() == false) {
    temp_error_messagepgm(PSTR("MAXTEMP"), e);
  }
  #ifndef BOGUS_TEMPERATURE_FAILSAFE_OVERRIDE
  Stop();
  #endif

    SET_OUTPUT(FAN_PIN);
    SET_OUTPUT(BEEPER);
    WRITE(FAN_PIN, 1);
    WRITE(BEEPER, 1);
#ifdef EXTRUDER_ALTFAN_DETECT
    altfanStatus.altfanOverride = 1; //full speed
#endif //EXTRUDER_ALTFAN_DETECT
    setExtruderAutoFanState(3);
    // fanSpeed will consumed by the check_axes_activity() routine.
    fanSpeed=255;
	if (farm_mode) { prusa_statistics(93); }
}

void min_temp_error(uint8_t e) {
#ifdef DEBUG_DISABLE_MINTEMP
	return;
#endif
  disable_heater();
//if (current_temperature_ambient < MINTEMP_MINAMBIENT) return;
	static const char err[] PROGMEM = "MINTEMP";
  if(IsStopped() == false) {
    temp_error_messagepgm(err, e);
    last_alert_sent_to_lcd = LCDALERT_HEATERMINTEMP;
  } else if( last_alert_sent_to_lcd != LCDALERT_HEATERMINTEMP ){ // only update, if the lcd message is to be changed (i.e. not the same as last time)
	// we are already stopped due to some error, only update the status message without flickering
    temp_update_messagepgm(err);
	last_alert_sent_to_lcd = LCDALERT_HEATERMINTEMP;
  }
  #ifndef BOGUS_TEMPERATURE_FAILSAFE_OVERRIDE
//	if( last_alert_sent_to_lcd != LCDALERT_HEATERMINTEMP ){
//		last_alert_sent_to_lcd = LCDALERT_HEATERMINTEMP;
//		lcd_print_stop();
//	}
  Stop();
  #endif
  if (farm_mode) { prusa_statistics(92); }

}

void bed_max_temp_error(void) {
  disable_heater();
  if(IsStopped() == false) {
    temp_error_messagepgm(PSTR("MAXTEMP BED"));
  }
  #ifndef BOGUS_TEMPERATURE_FAILSAFE_OVERRIDE
  Stop();
  #endif
}

void bed_min_temp_error(void) {
#ifdef DEBUG_DISABLE_MINTEMP
	return;
#endif
    disable_heater();
    static const char err[] PROGMEM = "MINTEMP BED";
    if(IsStopped() == false) {
        temp_error_messagepgm(err);
		last_alert_sent_to_lcd = LCDALERT_BEDMINTEMP;
	} else if( last_alert_sent_to_lcd != LCDALERT_BEDMINTEMP ){ // only update, if the lcd message is to be changed (i.e. not the same as last time)
		// we are already stopped due to some error, only update the status message without flickering
        temp_update_messagepgm(err);
		last_alert_sent_to_lcd = LCDALERT_BEDMINTEMP;
    }
#ifndef BOGUS_TEMPERATURE_FAILSAFE_OVERRIDE
    Stop();
#endif
}


#ifdef AMBIENT_THERMISTOR
void ambient_max_temp_error(void) {
    disable_heater();
    if(IsStopped() == false) {
        temp_error_messagepgm(PSTR("MAXTEMP AMB"));
    }
#ifndef BOGUS_TEMPERATURE_FAILSAFE_OVERRIDE
    Stop();
#endif
}

void ambient_min_temp_error(void) {
#ifdef DEBUG_DISABLE_MINTEMP
	return;
#endif
    disable_heater();
    if(IsStopped() == false) {
        temp_error_messagepgm(PSTR("MINTEMP AMB"));
    }
#ifndef BOGUS_TEMPERATURE_FAILSAFE_OVERRIDE
    Stop();
#endif
}
#endif


#ifdef HEATER_0_USES_MAX6675
#define MAX6675_HEAT_INTERVAL 250
long max6675_previous_millis = MAX6675_HEAT_INTERVAL;
int max6675_temp = 2000;

int read_max6675()
{
  if (_millis() - max6675_previous_millis < MAX6675_HEAT_INTERVAL) 
    return max6675_temp;
  
  max6675_previous_millis = _millis();
  max6675_temp = 0;
    
  #ifdef	PRR
    PRR &= ~(1<<PRSPI);
  #elif defined PRR0
    PRR0 &= ~(1<<PRSPI);
  #endif
  
  SPCR = (1<<MSTR) | (1<<SPE) | (1<<SPR0);
  
  // enable TT_MAX6675
  WRITE(MAX6675_SS, 0);
  
  // ensure 100ns delay - a bit extra is fine
  asm("nop");//50ns on 20Mhz, 62.5ns on 16Mhz
  asm("nop");//50ns on 20Mhz, 62.5ns on 16Mhz
  
  // read MSB
  SPDR = 0;
  for (;(SPSR & (1<<SPIF)) == 0;);
  max6675_temp = SPDR;
  max6675_temp <<= 8;
  
  // read LSB
  SPDR = 0;
  for (;(SPSR & (1<<SPIF)) == 0;);
  max6675_temp |= SPDR;
  
  // disable TT_MAX6675
  WRITE(MAX6675_SS, 1);

  if (max6675_temp & 4) 
  {
    // thermocouple open
    max6675_temp = 2000;
  }
  else 
  {
    max6675_temp = max6675_temp >> 3;
  }

  return max6675_temp;
}
#endif


extern "C" {


void adc_ready(void) //callback from adc when sampling finished
{
	current_temperature_raw[0] = adc_values[ADC_PIN_IDX(TEMP_0_PIN)]; //heater
#ifdef PINDA_THERMISTOR
	current_temperature_raw_pinda_fast = adc_values[ADC_PIN_IDX(TEMP_PINDA_PIN)];
#endif //PINDA_THERMISTOR
	current_temperature_bed_raw = adc_values[ADC_PIN_IDX(TEMP_BED_PIN)];
#ifdef VOLT_PWR_PIN
	current_voltage_raw_pwr = adc_values[ADC_PIN_IDX(VOLT_PWR_PIN)];
#endif
#ifdef AMBIENT_THERMISTOR
	current_temperature_raw_ambient = adc_values[ADC_PIN_IDX(TEMP_AMBIENT_PIN)]; // 5->6
#endif //AMBIENT_THERMISTOR
#ifdef VOLT_BED_PIN
	current_voltage_raw_bed = adc_values[ADC_PIN_IDX(VOLT_BED_PIN)]; // 6->9
#endif
#ifdef IR_SENSOR_ANALOG
     current_voltage_raw_IR = adc_values[ADC_PIN_IDX(VOLT_IR_PIN)];
#endif //IR_SENSOR_ANALOG
	temp_meas_ready = true;
}

} // extern "C"

FORCE_INLINE static void temperature_isr()
{
	if (!temp_meas_ready) adc_cycle();
	lcd_buttons_update();

  static uint8_t pwm_count = (1 << SOFT_PWM_SCALE);
  static uint8_t soft_pwm_0;
#ifdef SLOW_PWM_HEATERS
  static unsigned char slow_pwm_count = 0;
  static unsigned char state_heater_0 = 0;
  static unsigned char state_timer_heater_0 = 0;
#endif 
#if (EXTRUDERS > 1) || defined(HEATERS_PARALLEL)
  static unsigned char soft_pwm_1;
#ifdef SLOW_PWM_HEATERS
  static unsigned char state_heater_1 = 0;
  static unsigned char state_timer_heater_1 = 0;
#endif 
#endif
#if EXTRUDERS > 2
  static unsigned char soft_pwm_2;
#ifdef SLOW_PWM_HEATERS
  static unsigned char state_heater_2 = 0;
  static unsigned char state_timer_heater_2 = 0;
#endif 
#endif
#if HEATER_BED_PIN > -1
  // @@DR static unsigned char soft_pwm_b;
#ifdef SLOW_PWM_HEATERS
  static unsigned char state_heater_b = 0;
  static unsigned char state_timer_heater_b = 0;
#endif 
#endif
  
#if defined(FILWIDTH_PIN) &&(FILWIDTH_PIN > -1)
  static unsigned long raw_filwidth_value = 0;  //added for filament width sensor
#endif
  
#ifndef SLOW_PWM_HEATERS
  /*
   * standard PWM modulation
   */
  if (pwm_count == 0)
  {
    soft_pwm_0 = soft_pwm[0];
    if(soft_pwm_0 > 0)
	{ 
      WRITE(HEATER_0_PIN,1);
#ifdef HEATERS_PARALLEL
      WRITE(HEATER_1_PIN,1);
#endif
    } else WRITE(HEATER_0_PIN,0);
#if EXTRUDERS > 1
    soft_pwm_1 = soft_pwm[1];
    if(soft_pwm_1 > 0) WRITE(HEATER_1_PIN,1); else WRITE(HEATER_1_PIN,0);
#endif
#if EXTRUDERS > 2
    soft_pwm_2 = soft_pwm[2];
    if(soft_pwm_2 > 0) WRITE(HEATER_2_PIN,1); else WRITE(HEATER_2_PIN,0);
#endif
  }
#if defined(HEATER_BED_PIN) && HEATER_BED_PIN > -1
  
#if 0  // @@DR vypnuto pro hw pwm bedu
  // tuhle prasarnu bude potreba poustet ve stanovenych intervalech, jinak nemam moc sanci zareagovat
  // teoreticky by se tato cast uz vubec nemusela poustet
  if ((pwm_count & ((1 << HEATER_BED_SOFT_PWM_BITS) - 1)) == 0)
  {
    soft_pwm_b = soft_pwm_bed >> (7 - HEATER_BED_SOFT_PWM_BITS);
#  ifndef SYSTEM_TIMER_2
	// tady budu krokovat pomalou frekvenci na automatu - tohle je rizeni spinani a rozepinani
	// jako ridici frekvenci mam 2khz, jako vystupni frekvenci mam 30hz
	// 2kHz jsou ovsem ve slysitelnem pasmu, mozna bude potreba jit s frekvenci nahoru (a tomu taky prizpusobit ostatni veci)
	// Teoreticky bych mohl stahnout OCR0B citac na 6, cimz bych se dostal nekam ke 40khz a tady potom honit PWM rychleji nebo i pomaleji
	// to nicemu nevadi. Soft PWM scale by se 20x zvetsilo (no dobre, 16x), cimz by se to posunulo k puvodnimu 30Hz PWM
	//if(soft_pwm_b > 0) WRITE(HEATER_BED_PIN,1); else WRITE(HEATER_BED_PIN,0);
#  endif //SYSTEM_TIMER_2
  }
#endif
#endif
  
#ifdef FAN_SOFT_PWM
  if ((pwm_count & ((1 << FAN_SOFT_PWM_BITS) - 1)) == 0)
  {
    soft_pwm_fan = fanSpeedSoftPwm / (1 << (8 - FAN_SOFT_PWM_BITS));
    if(soft_pwm_fan > 0) WRITE(FAN_PIN,1); else WRITE(FAN_PIN,0);
  }
#endif
  if(soft_pwm_0 < pwm_count)
  { 
    WRITE(HEATER_0_PIN,0);
#ifdef HEATERS_PARALLEL
    WRITE(HEATER_1_PIN,0);
#endif
  }

#if EXTRUDERS > 1
  if(soft_pwm_1 < pwm_count) WRITE(HEATER_1_PIN,0);
#endif
#if EXTRUDERS > 2
  if(soft_pwm_2 < pwm_count) WRITE(HEATER_2_PIN,0);
#endif

#if 0 // @@DR  
#if defined(HEATER_BED_PIN) && HEATER_BED_PIN > -1
  if (soft_pwm_b < (pwm_count & ((1 << HEATER_BED_SOFT_PWM_BITS) - 1))){
	  //WRITE(HEATER_BED_PIN,0);
  }
  //WRITE(HEATER_BED_PIN, pwm_count & 1 );
#endif
#endif
#ifdef FAN_SOFT_PWM
  if (soft_pwm_fan < (pwm_count & ((1 << FAN_SOFT_PWM_BITS) - 1))) WRITE(FAN_PIN,0);
#endif
  
  pwm_count += (1 << SOFT_PWM_SCALE);
  pwm_count &= 0x7f;

#else //ifndef SLOW_PWM_HEATERS
  /*
   * SLOW PWM HEATERS
   *
   * for heaters drived by relay
   */
#ifndef MIN_STATE_TIME
#define MIN_STATE_TIME 16 // MIN_STATE_TIME * 65.5 = time in milliseconds
#endif
  if (slow_pwm_count == 0) {
    // EXTRUDER 0 
    soft_pwm_0 = soft_pwm[0];
    if (soft_pwm_0 > 0) {
      // turn ON heather only if the minimum time is up 
      if (state_timer_heater_0 == 0) { 
	// if change state set timer 
	if (state_heater_0 == 0) {
	  state_timer_heater_0 = MIN_STATE_TIME;
	}
	state_heater_0 = 1;
	WRITE(HEATER_0_PIN, 1);
#ifdef HEATERS_PARALLEL
	WRITE(HEATER_1_PIN, 1);
#endif
      }
    } else {
      // turn OFF heather only if the minimum time is up 
      if (state_timer_heater_0 == 0) {
	// if change state set timer 
	if (state_heater_0 == 1) {
	  state_timer_heater_0 = MIN_STATE_TIME;
	}
	state_heater_0 = 0;
	WRITE(HEATER_0_PIN, 0);
#ifdef HEATERS_PARALLEL
	WRITE(HEATER_1_PIN, 0);
#endif
      }
    }
    
#if EXTRUDERS > 1
    // EXTRUDER 1
    soft_pwm_1 = soft_pwm[1];
    if (soft_pwm_1 > 0) {
      // turn ON heather only if the minimum time is up 
      if (state_timer_heater_1 == 0) { 
	// if change state set timer 
	if (state_heater_1 == 0) {
	  state_timer_heater_1 = MIN_STATE_TIME;
	}
	state_heater_1 = 1;
	WRITE(HEATER_1_PIN, 1);
      }
    } else {
      // turn OFF heather only if the minimum time is up 
      if (state_timer_heater_1 == 0) {
	// if change state set timer 
	if (state_heater_1 == 1) {
	  state_timer_heater_1 = MIN_STATE_TIME;
	}
	state_heater_1 = 0;
	WRITE(HEATER_1_PIN, 0);
      }
    }
#endif
    
#if EXTRUDERS > 2
    // EXTRUDER 2
    soft_pwm_2 = soft_pwm[2];
    if (soft_pwm_2 > 0) {
      // turn ON heather only if the minimum time is up 
      if (state_timer_heater_2 == 0) { 
	// if change state set timer 
	if (state_heater_2 == 0) {
	  state_timer_heater_2 = MIN_STATE_TIME;
	}
	state_heater_2 = 1;
	WRITE(HEATER_2_PIN, 1);
      }
    } else {
      // turn OFF heather only if the minimum time is up 
      if (state_timer_heater_2 == 0) {
	// if change state set timer 
	if (state_heater_2 == 1) {
	  state_timer_heater_2 = MIN_STATE_TIME;
	}
	state_heater_2 = 0;
	WRITE(HEATER_2_PIN, 0);
      }
    }
#endif
    
#if defined(HEATER_BED_PIN) && HEATER_BED_PIN > -1
    // BED
    soft_pwm_b = soft_pwm_bed;
    if (soft_pwm_b > 0) {
      // turn ON heather only if the minimum time is up 
      if (state_timer_heater_b == 0) { 
	// if change state set timer 
	if (state_heater_b == 0) {
	  state_timer_heater_b = MIN_STATE_TIME;
	}
	state_heater_b = 1;
	//WRITE(HEATER_BED_PIN, 1);
      }
    } else {
      // turn OFF heather only if the minimum time is up 
      if (state_timer_heater_b == 0) {
	// if change state set timer 
	if (state_heater_b == 1) {
	  state_timer_heater_b = MIN_STATE_TIME;
	}
	state_heater_b = 0;
	WRITE(HEATER_BED_PIN, 0);
      }
    }
#endif
  } // if (slow_pwm_count == 0)
  
  // EXTRUDER 0 
  if (soft_pwm_0 < slow_pwm_count) {
    // turn OFF heather only if the minimum time is up 
    if (state_timer_heater_0 == 0) { 
      // if change state set timer 
      if (state_heater_0 == 1) {
	state_timer_heater_0 = MIN_STATE_TIME;
      }
      state_heater_0 = 0;
      WRITE(HEATER_0_PIN, 0);
#ifdef HEATERS_PARALLEL
      WRITE(HEATER_1_PIN, 0);
#endif
    }
  }
    
#if EXTRUDERS > 1
  // EXTRUDER 1 
  if (soft_pwm_1 < slow_pwm_count) {
    // turn OFF heather only if the minimum time is up 
    if (state_timer_heater_1 == 0) { 
      // if change state set timer 
      if (state_heater_1 == 1) {
	state_timer_heater_1 = MIN_STATE_TIME;
      }
      state_heater_1 = 0;
      WRITE(HEATER_1_PIN, 0);
    }
  }
#endif
  
#if EXTRUDERS > 2
  // EXTRUDER 2
  if (soft_pwm_2 < slow_pwm_count) {
    // turn OFF heather only if the minimum time is up 
    if (state_timer_heater_2 == 0) { 
      // if change state set timer 
      if (state_heater_2 == 1) {
	state_timer_heater_2 = MIN_STATE_TIME;
      }
      state_heater_2 = 0;
      WRITE(HEATER_2_PIN, 0);
    }
  }
#endif
  
#if defined(HEATER_BED_PIN) && HEATER_BED_PIN > -1
  // BED
  if (soft_pwm_b < slow_pwm_count) {
    // turn OFF heather only if the minimum time is up 
    if (state_timer_heater_b == 0) { 
      // if change state set timer 
      if (state_heater_b == 1) {
	state_timer_heater_b = MIN_STATE_TIME;
      }
      state_heater_b = 0;
      WRITE(HEATER_BED_PIN, 0);
    }
  }
#endif
  
#ifdef FAN_SOFT_PWM
  if ((pwm_count & ((1 << FAN_SOFT_PWM_BITS) - 1)) == 0)
    soft_pwm_fan = fanSpeedSoftPwm / (1 << (8 - FAN_SOFT_PWM_BITS));
    if (soft_pwm_fan > 0) WRITE(FAN_PIN,1); else WRITE(FAN_PIN,0);
  }
  if (soft_pwm_fan < pwm_count) WRITE(FAN_PIN,0);
#endif

  pwm_count += (1 << SOFT_PWM_SCALE);
  pwm_count &= 0x7f;
  
  // increment slow_pwm_count only every 64 pwm_count circa 65.5ms
  if ((pwm_count % 64) == 0) {
    slow_pwm_count++;
    slow_pwm_count &= 0x7f;
    
    // Extruder 0
    if (state_timer_heater_0 > 0) {
      state_timer_heater_0--;
    } 
  
#if EXTRUDERS > 1
    // Extruder 1
    if (state_timer_heater_1 > 0) 
      state_timer_heater_1--;
#endif
    
#if EXTRUDERS > 2
    // Extruder 2
    if (state_timer_heater_2 > 0) 
      state_timer_heater_2--;
#endif
    
#if defined(HEATER_BED_PIN) && HEATER_BED_PIN > -1
    // Bed   
    if (state_timer_heater_b > 0) 
      state_timer_heater_b--;
#endif
  } //if ((pwm_count % 64) == 0) {
  
#endif //ifndef SLOW_PWM_HEATERS

  
#ifdef BABYSTEPPING
  for(uint8_t axis=0;axis<3;axis++)
  {
    int curTodo=babystepsTodo[axis]; //get rid of volatile for performance
   
    if(curTodo>0)
    {
      CRITICAL_SECTION_START;
      babystep(axis,/*fwd*/true);
      babystepsTodo[axis]--; //less to do next time
      CRITICAL_SECTION_END;
    }
    else
    if(curTodo<0)
    {
      CRITICAL_SECTION_START;
      babystep(axis,/*fwd*/false);
      babystepsTodo[axis]++; //less to do next time
      CRITICAL_SECTION_END;
    }
  }
#endif //BABYSTEPPING

  // Check if a stack overflow happened
  if (!SdFatUtil::test_stack_integrity()) stack_error();

#if (defined(FANCHECK) && defined(TACH_0) && (TACH_0 > -1))
  check_fans();
#endif //(defined(TACH_0))
}

// Timer2 (originaly timer0) is shared with millies
#ifdef SYSTEM_TIMER_2
ISR(TIMER2_COMPB_vect)
#else //SYSTEM_TIMER_2
ISR(TIMER0_COMPB_vect)
#endif //SYSTEM_TIMER_2
{
    static bool _lock = false;
    if (!_lock)
    {
        _lock = true;
        sei();
        temperature_isr();
        cli();
        _lock = false;
    }
}

void check_max_temp()
{
//heater
#if HEATER_0_RAW_LO_TEMP > HEATER_0_RAW_HI_TEMP
    if (current_temperature_raw[0] <= maxttemp_raw[0]) {
#else
    if (current_temperature_raw[0] >= maxttemp_raw[0]) {
#endif
        max_temp_error(0);
    }
//bed
#if defined(BED_MAXTEMP) && (TEMP_SENSOR_BED != 0)
#if HEATER_BED_RAW_LO_TEMP > HEATER_BED_RAW_HI_TEMP
    if (current_temperature_bed_raw <= bed_maxttemp_raw) {
#else
    if (current_temperature_bed_raw >= bed_maxttemp_raw) {
#endif
       bed_max_temp_error();
    }
#endif
//ambient
#if defined(AMBIENT_MAXTEMP) && (TEMP_SENSOR_AMBIENT != 0)
#if AMBIENT_RAW_LO_TEMP > AMBIENT_RAW_HI_TEMP
    if (current_temperature_raw_ambient <= ambient_maxttemp_raw) {
#else
    if (current_temperature_raw_ambient >= ambient_maxttemp_raw) {
#endif
       ambient_max_temp_error();
    }
#endif
}
//! number of repeating the same state with consecutive step() calls
//! used to slow down text switching
struct alert_automaton_mintemp {
	const char *m2;
	alert_automaton_mintemp(const char *m2):m2(m2){}
private:
	enum { ALERT_AUTOMATON_SPEED_DIV = 5 };
	enum class States : uint8_t { Init = 0, TempAboveMintemp, ShowPleaseRestart, ShowMintemp };
	States state = States::Init;
	uint8_t repeat = ALERT_AUTOMATON_SPEED_DIV;

	void substep(States next_state){
		if( repeat == 0 ){
			state = next_state; // advance to the next state
			repeat = ALERT_AUTOMATON_SPEED_DIV; // and prepare repeating for it too
		} else {
			--repeat;
		}
	}
public:
	//! brief state automaton step routine
	//! @param current_temp current hotend/bed temperature (for computing simple hysteresis)
	//! @param mintemp minimal temperature including hysteresis to check current_temp against
	void step(float current_temp, float mintemp){
		static const char m1[] PROGMEM = "Please restart";
		switch(state){
		case States::Init: // initial state - check hysteresis
			if( current_temp > mintemp ){
				state = States::TempAboveMintemp;
			}
			// otherwise keep the Err MINTEMP alert message on the display,
			// i.e. do not transfer to state 1
			break;
		case States::TempAboveMintemp: // the temperature has risen above the hysteresis check
			lcd_setalertstatuspgm(m2);
			substep(States::ShowMintemp);
			last_alert_sent_to_lcd = LCDALERT_MINTEMPFIXED;
			break;
		case States::ShowPleaseRestart: // displaying "Please restart"
			lcd_updatestatuspgm(m1);
			substep(States::ShowMintemp);
			last_alert_sent_to_lcd = LCDALERT_PLEASERESTART;
			break;
		case States::ShowMintemp: // displaying "MINTEMP fixed"
			lcd_updatestatuspgm(m2);
			substep(States::ShowPleaseRestart);
			last_alert_sent_to_lcd = LCDALERT_MINTEMPFIXED;
			break;
		}
	}
};
static const char m2hotend[] PROGMEM = "MINTEMP HOTEND fixed";
static const char m2bed[] PROGMEM = "MINTEMP BED fixed";
static alert_automaton_mintemp alert_automaton_hotend(m2hotend), alert_automaton_bed(m2bed);

void check_min_temp_heater0()
{
//heater
#if HEATER_0_RAW_LO_TEMP > HEATER_0_RAW_HI_TEMP
	if (current_temperature_raw[0] >= minttemp_raw[0]) {
#else
	if (current_temperature_raw[0] <= minttemp_raw[0]) {
#endif
		menu_set_serious_error(SERIOUS_ERR_MINTEMP_HEATER);
		min_temp_error(0);
	} else if( menu_is_serious_error(SERIOUS_ERR_MINTEMP_HEATER) ) {
		// no recovery, just force the user to restart the printer
		// which is a safer variant than just continuing printing
		// The automaton also checks for hysteresis - the temperature must have reached a few degrees above the MINTEMP, before
		// we shall signalize, that MINTEMP has been fixed
		// Code notice: normally the alert_automaton instance would have been placed here 
		// as static alert_automaton_mintemp alert_automaton_hotend, but
		// due to stupid compiler that takes 16 more bytes.
		alert_automaton_hotend.step(current_temperature[0], minttemp[0] + TEMP_HYSTERESIS);
	}
}

void check_min_temp_bed()
{
#if HEATER_BED_RAW_LO_TEMP > HEATER_BED_RAW_HI_TEMP
	if (current_temperature_bed_raw >= bed_minttemp_raw) {
#else
	if (current_temperature_bed_raw <= bed_minttemp_raw) {
#endif
		menu_set_serious_error(SERIOUS_ERR_MINTEMP_BED);
		bed_min_temp_error();
	} else if( menu_is_serious_error(SERIOUS_ERR_MINTEMP_BED) ){
		// no recovery, just force the user to restart the printer
		// which is a safer variant than just continuing printing
		alert_automaton_bed.step(current_temperature_bed, BED_MINTEMP + TEMP_HYSTERESIS);
	}
}

#ifdef AMBIENT_MINTEMP
void check_min_temp_ambient()
{
#if AMBIENT_RAW_LO_TEMP > AMBIENT_RAW_HI_TEMP
	if (current_temperature_raw_ambient >= ambient_minttemp_raw) {
#else
	if (current_temperature_raw_ambient <= ambient_minttemp_raw) {
#endif
		ambient_min_temp_error();
	}
}
#endif

void check_min_temp()
{
static bool bCheckingOnHeater=false;              // state variable, which allows to short no-checking delay (is set, when temperature is (first time) over heaterMintemp)
static bool bCheckingOnBed=false;                 // state variable, which allows to short no-checking delay (is set, when temperature is (first time) over bedMintemp)
#ifdef AMBIENT_THERMISTOR
#ifdef AMBIENT_MINTEMP
check_min_temp_ambient();
#endif
#if AMBIENT_RAW_LO_TEMP > AMBIENT_RAW_HI_TEMP
if(current_temperature_raw_ambient>(OVERSAMPLENR*MINTEMP_MINAMBIENT_RAW)) // thermistor is NTC type
#else
if(current_temperature_raw_ambient=<(OVERSAMPLENR*MINTEMP_MINAMBIENT_RAW))
#endif
     {                                            // ambient temperature is low
#endif //AMBIENT_THERMISTOR
// *** 'common' part of code for MK2.5 & MK3
// * nozzle checking
if(target_temperature[active_extruder]>minttemp[active_extruder])
     {                                            // ~ nozzle heating is on
     bCheckingOnHeater=bCheckingOnHeater||(current_temperature[active_extruder]>(minttemp[active_extruder]+TEMP_HYSTERESIS)); // for eventually delay cutting
     if(oTimer4minTempHeater.expired(HEATER_MINTEMP_DELAY)||(!oTimer4minTempHeater.running())||bCheckingOnHeater)
          {
          bCheckingOnHeater=true;                 // not necessary
		check_min_temp_heater0();               // delay is elapsed or temperature is/was over minTemp => periodical checking is active
          }
     }
else {                                            // ~ nozzle heating is off
     oTimer4minTempHeater.start();
     bCheckingOnHeater=false;
     }
// * bed checking
if(target_temperature_bed>BED_MINTEMP)
     {                                            // ~ bed heating is on
     bCheckingOnBed=bCheckingOnBed||(current_temperature_bed>(BED_MINTEMP+TEMP_HYSTERESIS)); // for eventually delay cutting
     if(oTimer4minTempBed.expired(BED_MINTEMP_DELAY)||(!oTimer4minTempBed.running())||bCheckingOnBed)
          {
          bCheckingOnBed=true;                    // not necessary
		check_min_temp_bed();                   // delay is elapsed or temperature is/was over minTemp => periodical checking is active
          }
     }
else {                                            // ~ bed heating is off
     oTimer4minTempBed.start();
     bCheckingOnBed=false;
     }
// *** end of 'common' part
#ifdef AMBIENT_THERMISTOR
     }
else {                                            // ambient temperature is standard
     check_min_temp_heater0();
     check_min_temp_bed();
     }
#endif //AMBIENT_THERMISTOR
}
 
#if (defined(FANCHECK) && defined(TACH_0) && (TACH_0 > -1))
void check_fans() {
#ifdef FAN_SOFT_PWM
	if (READ(TACH_0) != fan_state[0]) {
		if(fan_measuring) fan_edge_counter[0] ++;
		fan_state[0] = !fan_state[0];
	}
#else //FAN_SOFT_PWM
	if (READ(TACH_0) != fan_state[0]) {
		fan_edge_counter[0] ++;
		fan_state[0] = !fan_state[0];
	}
#endif
	//if (READ(TACH_1) != fan_state[1]) {
	//	fan_edge_counter[1] ++;
	//	fan_state[1] = !fan_state[1];
	//}
}
#endif //TACH_0

#ifdef PIDTEMP
// Apply the scale factors to the PID values


float scalePID_i(float i)
{
	return i*PID_dT;
}

float unscalePID_i(float i)
{
	return i/PID_dT;
}

float scalePID_d(float d)
{
    return d/PID_dT;
}

float unscalePID_d(float d)
{
	return d*PID_dT;
}

#endif //PIDTEMP

#ifdef PINDA_THERMISTOR
//! @brief PINDA thermistor detected
//!
//! @retval true firmware should do temperature compensation and allow calibration
//! @retval false PINDA thermistor is not detected, disable temperature compensation and calibration
//! @retval true/false when forced via LCD menu Settings->HW Setup->SuperPINDA
//!
bool has_temperature_compensation()
{
#ifdef SUPERPINDA_SUPPORT
#ifdef PINDA_TEMP_COMP
   	uint8_t pinda_temp_compensation = eeprom_read_byte((uint8_t*)EEPROM_PINDA_TEMP_COMPENSATION);
    if (pinda_temp_compensation == EEPROM_EMPTY_VALUE) //Unkown PINDA temp compenstation, so check it.
      {
#endif //PINDA_TEMP_COMP
        return (current_temperature_pinda >= PINDA_MINTEMP) ? true : false;
#ifdef PINDA_TEMP_COMP
      }
    else if (pinda_temp_compensation == 0) return true; //Overwritten via LCD menu SuperPINDA [No]
    else return false; //Overwritten via LCD menu SuperPINDA [YES]
#endif //PINDA_TEMP_COMP
#else
    return true;
#endif
}
#endif //PINDA_THERMISTOR