text: /*
    temperature.cpp - 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/>.
  */
  
  #include "Marlin.h"
  #include "ultralcd.h"
  #include "temperature.h"
  #include "watchdog.h"
  #include "language.h"
  
  #include "Sd2PinMap.h"
  
  //===========================================================================
  //================================== macros =================================
  //===========================================================================
  
  #ifdef K1 // Defined in Configuration.h in the PID settings
    #define K2 (1.0-K1)
  #endif
  
  #if defined(PIDTEMPBED) || defined(PIDTEMP)
    #define PID_dT (((OVERSAMPLENR + 2) * 12.0)/ TEMP_FREQUENCY)
    #define RECI_PID_dT ( 1 / PID_dT )
  #endif
  
  //===========================================================================
  //============================= public variables ============================
  //===========================================================================
  
  int target_temperature[4] = { 0 };
  int target_temperature_bed = 0;
  int current_temperature_raw[4] = { 0 };
  float current_temperature[4] = { 0.0 };
  int current_temperature_bed_raw = 0;
  float current_temperature_bed = 0.0;
  #ifdef TEMP_SENSOR_1_AS_REDUNDANT
    int redundant_temperature_raw = 0;
    float redundant_temperature = 0.0;
  #endif
  
  #ifdef PIDTEMPBED
    float bedKp=DEFAULT_bedKp;
    float bedKi=(DEFAULT_bedKi*PID_dT);
    float bedKd=(DEFAULT_bedKd/PID_dT);
  #endif //PIDTEMPBED
    
  #ifdef FAN_SOFT_PWM
    unsigned char fanSpeedSoftPwm;
  #endif
  
  unsigned char soft_pwm_bed;
    
  #ifdef BABYSTEPPING
    volatile int babystepsTodo[3] = { 0 };
  #endif
  
  #ifdef FILAMENT_SENSOR
    int current_raw_filwidth = 0;  //Holds measured filament diameter - one extruder only
  #endif  
  
  #if defined(THERMAL_PROTECTION_HOTENDS) || defined(THERMAL_PROTECTION_BED)
    enum TRState { TRReset, TRInactive, TRFirstHeating, TRStable, TRRunaway };
    void thermal_runaway_protection(TRState *state, millis_t *timer, float temperature, float target_temperature, int heater_id, int period_seconds, int hysteresis_degc);
    #ifdef THERMAL_PROTECTION_HOTENDS
      static TRState thermal_runaway_state_machine[4] = { TRReset, TRReset, TRReset, TRReset };
      static millis_t thermal_runaway_timer[4]; // = {0,0,0,0};
    #endif
    #ifdef THERMAL_PROTECTION_BED
      static TRState thermal_runaway_bed_state_machine = TRReset;
      static millis_t thermal_runaway_bed_timer;
    #endif
  #endif
  
  //===========================================================================
  //============================ private variables ============================
  //===========================================================================
  
  static volatile bool temp_meas_ready = false;
  
  #ifdef PIDTEMP
    //static cannot be external:
    static float temp_iState[EXTRUDERS] = { 0 };
    static float temp_dState[EXTRUDERS] = { 0 };
    static float pTerm[EXTRUDERS];
    static float iTerm[EXTRUDERS];
    static float dTerm[EXTRUDERS];
    //int output;
    static float pid_error[EXTRUDERS];
    static float temp_iState_min[EXTRUDERS];
    static float temp_iState_max[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 millis_t  next_bed_check_ms;
  #endif //PIDTEMPBED
    static unsigned char soft_pwm[EXTRUDERS];
  
  #ifdef FAN_SOFT_PWM
    static unsigned char soft_pwm_fan;
  #endif
  #if HAS_AUTO_FAN
    static millis_t next_auto_fan_check_ms;
  #endif  
  
  #ifdef PIDTEMP
    #ifdef PID_PARAMS_PER_EXTRUDER
      float Kp[EXTRUDERS] = ARRAY_BY_EXTRUDERS(DEFAULT_Kp, DEFAULT_Kp, DEFAULT_Kp, DEFAULT_Kp);
      float Ki[EXTRUDERS] = ARRAY_BY_EXTRUDERS(DEFAULT_Ki*PID_dT, DEFAULT_Ki*PID_dT, DEFAULT_Ki*PID_dT, DEFAULT_Ki*PID_dT);
      float Kd[EXTRUDERS] = ARRAY_BY_EXTRUDERS(DEFAULT_Kd / PID_dT, DEFAULT_Kd / PID_dT, DEFAULT_Kd / PID_dT, DEFAULT_Kd / PID_dT);
      #ifdef PID_ADD_EXTRUSION_RATE
        float Kc[EXTRUDERS] = ARRAY_BY_EXTRUDERS(DEFAULT_Kc, DEFAULT_Kc, DEFAULT_Kc, DEFAULT_Kc);
      #endif // PID_ADD_EXTRUSION_RATE
    #else //PID_PARAMS_PER_EXTRUDER
      float Kp = DEFAULT_Kp;
      float Ki = DEFAULT_Ki * PID_dT;
      float Kd = DEFAULT_Kd / PID_dT;
      #ifdef PID_ADD_EXTRUSION_RATE
        float Kc = DEFAULT_Kc;
      #endif // PID_ADD_EXTRUSION_RATE
    #endif // PID_PARAMS_PER_EXTRUDER
  #endif //PIDTEMP
  
  // 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, HEATER_3_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, HEATER_3_RAW_HI_TEMP);
  static int minttemp[EXTRUDERS] = { 0 };
  static int maxttemp[EXTRUDERS] = ARRAY_BY_EXTRUDERS( 16383, 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 TEMP_SENSOR_1_AS_REDUNDANT
    static void *heater_ttbl_map[2] = {(void *)HEATER_0_TEMPTABLE, (void *)HEATER_1_TEMPTABLE };
    static uint8_t heater_ttbllen_map[2] = { HEATER_0_TEMPTABLE_LEN, HEATER_1_TEMPTABLE_LEN };
  #else
    static void *heater_ttbl_map[EXTRUDERS] = ARRAY_BY_EXTRUDERS( (void *)HEATER_0_TEMPTABLE, (void *)HEATER_1_TEMPTABLE, (void *)HEATER_2_TEMPTABLE, (void *)HEATER_3_TEMPTABLE );
    static uint8_t heater_ttbllen_map[EXTRUDERS] = ARRAY_BY_EXTRUDERS( HEATER_0_TEMPTABLE_LEN, HEATER_1_TEMPTABLE_LEN, HEATER_2_TEMPTABLE_LEN, HEATER_3_TEMPTABLE_LEN );
  #endif
  
  static float analog2temp(int raw, uint8_t e);
  static float analog2tempBed(int raw);
  static void updateTemperaturesFromRawValues();
  
  #ifdef THERMAL_PROTECTION_HOTENDS
    int watch_target_temp[EXTRUDERS] = { 0 };
    millis_t watch_heater_next_ms[EXTRUDERS] = { 0 };
  #endif
  
  #ifndef SOFT_PWM_SCALE
    #define SOFT_PWM_SCALE 0
  #endif
  
  #ifdef FILAMENT_SENSOR
    static int meas_shift_index;  //used to point to a delayed sample in buffer for filament width sensor
  #endif
  
  #ifdef HEATER_0_USES_MAX6675
    static int read_max6675();
  #endif
  
  //===========================================================================
  //================================ Functions ================================
  //===========================================================================
  
  void PID_autotune(float temp, int extruder, int ncycles) {
    float input = 0.0;
    int cycles = 0;
    bool heating = true;
  
    millis_t temp_ms = millis(), t1 = temp_ms, t2 = temp_ms;
    long t_high = 0, t_low = 0;
  
    long bias, d;
    float Ku, Tu;
    float Kp, Ki, Kd;
    float max = 0, min = 10000;
  
    #if HAS_AUTO_FAN
      millis_t next_auto_fan_check_ms = temp_ms + 2500;
    #endif
  
    if (extruder >= EXTRUDERS
      #if !HAS_TEMP_BED
         || extruder < 0
      #endif
    ) {
      SERIAL_ECHOLN(MSG_PID_BAD_EXTRUDER_NUM);
      return;
    }
    
    SERIAL_ECHOLN(MSG_PID_AUTOTUNE_START);
  
    disable_all_heaters(); // switch off all heaters.
  
    if (extruder < 0)
      soft_pwm_bed = bias = d = MAX_BED_POWER / 2;
    else
      soft_pwm[extruder] = bias = d = PID_MAX / 2;
  
    // PID Tuning loop
    for (;;) {
  
      millis_t ms = millis();
  
      if (temp_meas_ready) { // temp sample ready
        updateTemperaturesFromRawValues();
  
        input = (extruder<0)?current_temperature_bed:current_temperature[extruder];
  
        max = max(max, input);
        min = min(min, input);
  
        #if HAS_AUTO_FAN
          if (ms > next_auto_fan_check_ms) {
            checkExtruderAutoFans();
            next_auto_fan_check_ms = ms + 2500;
          }
        #endif
  
        if (heating && input > temp) {
          if (ms > t2 + 5000) {
            heating = false;
            if (extruder < 0)
              soft_pwm_bed = (bias - d) >> 1;
            else
              soft_pwm[extruder] = (bias - d) >> 1;
            t1 = ms;
            t_high = t1 - t2;
            max = temp;
          }
        }
  
        if (!heating && input < temp) {
          if (ms > t1 + 5000) {
            heating = true;
            t2 = ms;
            t_low = t2 - t1;
            if (cycles > 0) {
              long max_pow = extruder < 0 ? MAX_BED_POWER : PID_MAX;
              bias += (d*(t_high - t_low))/(t_low + t_high);
              bias = constrain(bias, 20, max_pow - 20);
              d = (bias > max_pow / 2) ? max_pow - 1 - bias : bias;
  
              SERIAL_PROTOCOLPGM(MSG_BIAS); SERIAL_PROTOCOL(bias);
              SERIAL_PROTOCOLPGM(MSG_D);    SERIAL_PROTOCOL(d);
              SERIAL_PROTOCOLPGM(MSG_T_MIN);  SERIAL_PROTOCOL(min);
              SERIAL_PROTOCOLPGM(MSG_T_MAX);  SERIAL_PROTOCOLLN(max);
              if (cycles > 2) {
                Ku = (4.0 * d) / (3.14159265 * (max - min) / 2.0);
                Tu = ((float)(t_low + t_high) / 1000.0);
                SERIAL_PROTOCOLPGM(MSG_KU); SERIAL_PROTOCOL(Ku);
                SERIAL_PROTOCOLPGM(MSG_TU); SERIAL_PROTOCOLLN(Tu);
                Kp = 0.6 * Ku;
                Ki = 2 * Kp / Tu;
                Kd = Kp * Tu / 8;
                SERIAL_PROTOCOLLNPGM(MSG_CLASSIC_PID);
                SERIAL_PROTOCOLPGM(MSG_KP); SERIAL_PROTOCOLLN(Kp);
                SERIAL_PROTOCOLPGM(MSG_KI); SERIAL_PROTOCOLLN(Ki);
                SERIAL_PROTOCOLPGM(MSG_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;
            else
              soft_pwm[extruder] = (bias + d) >> 1;
            cycles++;
            min = temp;
          }
        } 
      }
      #define MAX_OVERSHOOT_PID_AUTOTUNE 20
      if (input > temp + MAX_OVERSHOOT_PID_AUTOTUNE) {
        SERIAL_PROTOCOLLNPGM(MSG_PID_TEMP_TOO_HIGH);
        return;
      }
      // Every 2 seconds...
      if (ms > temp_ms + 2000) {
        int p;
        if (extruder < 0) {
          p = soft_pwm_bed;
          SERIAL_PROTOCOLPGM(MSG_B);
        }
        else {
          p = soft_pwm[extruder];
          SERIAL_PROTOCOLPGM(MSG_T);
        }
  
        SERIAL_PROTOCOL(input);
        SERIAL_PROTOCOLPGM(MSG_AT);
        SERIAL_PROTOCOLLN(p);
  
        temp_ms = ms;
      } // every 2 seconds
      // Over 2 minutes?
      if (((ms - t1) + (ms - t2)) > (10L*60L*1000L*2L)) {
        SERIAL_PROTOCOLLNPGM(MSG_PID_TIMEOUT);
        return;
      }
      if (cycles > ncycles) {
        SERIAL_PROTOCOLLNPGM(MSG_PID_AUTOTUNE_FINISHED);
        const char *estring = extruder < 0 ? "bed" : "";
        SERIAL_PROTOCOLPGM("#define  DEFAULT_"); SERIAL_PROTOCOL(estring); SERIAL_PROTOCOLPGM("Kp "); SERIAL_PROTOCOLLN(Kp);
        SERIAL_PROTOCOLPGM("#define  DEFAULT_"); SERIAL_PROTOCOL(estring); SERIAL_PROTOCOLPGM("Ki "); SERIAL_PROTOCOLLN(Ki);
        SERIAL_PROTOCOLPGM("#define  DEFAULT_"); SERIAL_PROTOCOL(estring); SERIAL_PROTOCOLPGM("Kd "); SERIAL_PROTOCOLLN(Kd);
        return;
      }
      lcd_update();
    }
  }
  
  void updatePID() {
    #ifdef PIDTEMP
      for (int e = 0; e < EXTRUDERS; e++) {
        temp_iState_max[e] = PID_INTEGRAL_DRIVE_MAX / PID_PARAM(Ki,e);
      }
    #endif
    #ifdef PIDTEMPBED
      temp_iState_max_bed = PID_BED_INTEGRAL_DRIVE_MAX / bedKi;
    #endif
  }
  
  int getHeaterPower(int heater) {
    return heater < 0 ? soft_pwm_bed : soft_pwm[heater];
  }
  
  #if HAS_AUTO_FAN
  
  void setExtruderAutoFanState(int pin, bool state) {
    unsigned char newFanSpeed = (state != 0) ? EXTRUDER_AUTO_FAN_SPEED : 0;
    // this idiom allows both digital and PWM fan outputs (see M42 handling).
    digitalWrite(pin, newFanSpeed);
    analogWrite(pin, newFanSpeed);
  }
  
  void checkExtruderAutoFans() {
    uint8_t fanState = 0;
  
    // which fan pins need to be turned on?      
    #if HAS_AUTO_FAN_0
      if (current_temperature[0] > EXTRUDER_AUTO_FAN_TEMPERATURE) 
        fanState |= 1;
    #endif
    #if HAS_AUTO_FAN_1
      if (current_temperature[1] > EXTRUDER_AUTO_FAN_TEMPERATURE) 
      {
        if (EXTRUDER_1_AUTO_FAN_PIN == EXTRUDER_0_AUTO_FAN_PIN)
          fanState |= 1;
        else
          fanState |= 2;
      }
    #endif
    #if HAS_AUTO_FAN_2
      if (current_temperature[2] > EXTRUDER_AUTO_FAN_TEMPERATURE) 
      {
        if (EXTRUDER_2_AUTO_FAN_PIN == EXTRUDER_0_AUTO_FAN_PIN) 
          fanState |= 1;
        else if (EXTRUDER_2_AUTO_FAN_PIN == EXTRUDER_1_AUTO_FAN_PIN) 
          fanState |= 2;
        else
          fanState |= 4;
      }
    #endif
    #if HAS_AUTO_FAN_3
      if (current_temperature[3] > EXTRUDER_AUTO_FAN_TEMPERATURE) 
      {
        if (EXTRUDER_3_AUTO_FAN_PIN == EXTRUDER_0_AUTO_FAN_PIN) 
          fanState |= 1;
        else if (EXTRUDER_3_AUTO_FAN_PIN == EXTRUDER_1_AUTO_FAN_PIN) 
          fanState |= 2;
        else if (EXTRUDER_3_AUTO_FAN_PIN == EXTRUDER_2_AUTO_FAN_PIN) 
          fanState |= 4;
        else
          fanState |= 8;
      }
    #endif
    
    // update extruder auto fan states
    #if HAS_AUTO_FAN_0
      setExtruderAutoFanState(EXTRUDER_0_AUTO_FAN_PIN, (fanState & 1) != 0);
    #endif
    #if HAS_AUTO_FAN_1
      if (EXTRUDER_1_AUTO_FAN_PIN != EXTRUDER_0_AUTO_FAN_PIN)
        setExtruderAutoFanState(EXTRUDER_1_AUTO_FAN_PIN, (fanState & 2) != 0);
    #endif
    #if HAS_AUTO_FAN_2
      if (EXTRUDER_2_AUTO_FAN_PIN != EXTRUDER_0_AUTO_FAN_PIN
          && EXTRUDER_2_AUTO_FAN_PIN != EXTRUDER_1_AUTO_FAN_PIN)
        setExtruderAutoFanState(EXTRUDER_2_AUTO_FAN_PIN, (fanState & 4) != 0);
    #endif
    #if HAS_AUTO_FAN_3
      if (EXTRUDER_3_AUTO_FAN_PIN != EXTRUDER_0_AUTO_FAN_PIN
          && EXTRUDER_3_AUTO_FAN_PIN != EXTRUDER_1_AUTO_FAN_PIN
          && EXTRUDER_3_AUTO_FAN_PIN != EXTRUDER_2_AUTO_FAN_PIN)
        setExtruderAutoFanState(EXTRUDER_3_AUTO_FAN_PIN, (fanState & 8) != 0);
    #endif
  }
  
  #endif // HAS_AUTO_FAN
  
  //
  // Temperature Error Handlers
  //
  inline void _temp_error(int e, const char *serial_msg, const char *lcd_msg) {
    static bool killed = false;
    if (IsRunning()) {
      SERIAL_ERROR_START;
      serialprintPGM(serial_msg);
      SERIAL_ERRORPGM(MSG_STOPPED_HEATER);
      if (e >= 0) SERIAL_ERRORLN((int)e); else SERIAL_ERRORLNPGM(MSG_HEATER_BED);
    }
    #ifndef BOGUS_TEMPERATURE_FAILSAFE_OVERRIDE
      if (!killed) {
        Running = false;
        killed = true;
        kill(lcd_msg);
      }
      else
        disable_all_heaters(); // paranoia
    #endif
  }
  
  void max_temp_error(uint8_t e) {
    _temp_error(e, PSTR(MSG_T_MAXTEMP), PSTR(MSG_ERR_MAXTEMP));
  }
  void min_temp_error(uint8_t e) {
    _temp_error(e, PSTR(MSG_T_MINTEMP), PSTR(MSG_ERR_MINTEMP));
  }
  
  float get_pid_output(int e) {
    float pid_output;
    #ifdef PIDTEMP
      #ifndef PID_OPENLOOP
        pid_error[e] = target_temperature[e] - current_temperature[e];
        if (pid_error[e] > PID_FUNCTIONAL_RANGE) {
          pid_output = BANG_MAX;
          pid_reset[e] = true;
        }
        else if (pid_error[e] < -PID_FUNCTIONAL_RANGE || target_temperature[e] == 0) {
          pid_output = 0;
          pid_reset[e] = true;
        }
        else {
          if (pid_reset[e]) {
            temp_iState[e] = 0.0;
            pid_reset[e] = false;
          }
          pTerm[e] = PID_PARAM(Kp,e) * pid_error[e];
          temp_iState[e] += pid_error[e];
          temp_iState[e] = constrain(temp_iState[e], temp_iState_min[e], temp_iState_max[e]);
          iTerm[e] = PID_PARAM(Ki,e) * temp_iState[e];
  
          dTerm[e] = K2 * PID_PARAM(Kd,e) * (current_temperature[e] - temp_dState[e]) + K1 * dTerm[e];
          pid_output = pTerm[e] + iTerm[e] - dTerm[e];
          if (pid_output > PID_MAX) {
            if (pid_error[e] > 0) temp_iState[e] -= pid_error[e]; // conditional un-integration
            pid_output = PID_MAX;
          }
          else if (pid_output < 0) {
            if (pid_error[e] < 0) temp_iState[e] -= pid_error[e]; // conditional un-integration
            pid_output = 0;
          }
        }
        temp_dState[e] = current_temperature[e];
      #else
        pid_output = constrain(target_temperature[e], 0, PID_MAX);
      #endif //PID_OPENLOOP
  
      #ifdef PID_DEBUG
        SERIAL_ECHO_START;
        SERIAL_ECHO(MSG_PID_DEBUG);
        SERIAL_ECHO(e);
        SERIAL_ECHO(MSG_PID_DEBUG_INPUT);
        SERIAL_ECHO(current_temperature[e]);
        SERIAL_ECHO(MSG_PID_DEBUG_OUTPUT);
        SERIAL_ECHO(pid_output);
        SERIAL_ECHO(MSG_PID_DEBUG_PTERM);
        SERIAL_ECHO(pTerm[e]);
        SERIAL_ECHO(MSG_PID_DEBUG_ITERM);
        SERIAL_ECHO(iTerm[e]);
        SERIAL_ECHO(MSG_PID_DEBUG_DTERM);
        SERIAL_ECHOLN(dTerm[e]);
      #endif //PID_DEBUG
  
    #else /* PID off */
      pid_output = (current_temperature[e] < target_temperature[e]) ? PID_MAX : 0;
    #endif
  
    return pid_output;
  }
  
  #ifdef PIDTEMPBED
    float get_pid_output_bed() {
      float pid_output;
      #ifndef PID_OPENLOOP
        pid_error_bed = target_temperature_bed - current_temperature_bed;
        pTerm_bed = 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 = bedKi * temp_iState_bed;
  
        dTerm_bed = K2 * bedKd * (current_temperature_bed - temp_dState_bed) + K1 * dTerm_bed;
        temp_dState_bed = current_temperature_bed;
  
        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
  
      #ifdef PID_BED_DEBUG
        SERIAL_ECHO_START;
        SERIAL_ECHO(" PID_BED_DEBUG ");
        SERIAL_ECHO(": Input ");
        SERIAL_ECHO(current_temperature_bed);
        SERIAL_ECHO(" Output ");
        SERIAL_ECHO(pid_output);
        SERIAL_ECHO(" pTerm ");
        SERIAL_ECHO(pTerm_bed);
        SERIAL_ECHO(" iTerm ");
        SERIAL_ECHO(iTerm_bed);
        SERIAL_ECHO(" dTerm ");
        SERIAL_ECHOLN(dTerm_bed);
      #endif //PID_BED_DEBUG
  
      return pid_output;
    }
  #endif
  
  /**
   * Manage heating activities for extruder hot-ends and a heated bed
   *  - Acquire updated temperature readings
   *  - Invoke thermal runaway protection
   *  - Manage extruder auto-fan
   *  - Apply filament width to the extrusion rate (may move)
   *  - Update the heated bed PID output value
   */
  void manage_heater() {
  
    if (!temp_meas_ready) return;
  
    updateTemperaturesFromRawValues();
  
    #ifdef HEATER_0_USES_MAX6675
      float ct = current_temperature[0];
      if (ct > min(HEATER_0_MAXTEMP, 1023)) max_temp_error(0);
      if (ct < max(HEATER_0_MINTEMP, 0.01)) min_temp_error(0);
    #endif
  
    #if defined(THERMAL_PROTECTION_HOTENDS) || !defined(PIDTEMPBED) || HAS_AUTO_FAN
      millis_t ms = millis();
    #endif
  
    // Loop through all extruders
    for (int e = 0; e < EXTRUDERS; e++) {
  
      #ifdef THERMAL_PROTECTION_HOTENDS
        thermal_runaway_protection(&thermal_runaway_state_machine[e], &thermal_runaway_timer[e], current_temperature[e], target_temperature[e], e, THERMAL_PROTECTION_PERIOD, THERMAL_PROTECTION_HYSTERESIS);
      #endif
  
      float pid_output = get_pid_output(e);
  
      // Check if temperature is within the correct range
      soft_pwm[e] = current_temperature[e] > minttemp[e] && current_temperature[e] < maxttemp[e] ? (int)pid_output >> 1 : 0;
  
      // Check if the temperature is failing to increase
      #ifdef THERMAL_PROTECTION_HOTENDS
  
        // Is it time to check this extruder's heater?
        if (watch_heater_next_ms[e] && ms > watch_heater_next_ms[e]) {
          // Has it failed to increase enough?
          if (degHotend(e) < watch_target_temp[e]) {
            // Stop!
            _temp_error(e, PSTR(MSG_T_HEATING_FAILED), PSTR(MSG_HEATING_FAILED_LCD));
          }
          else {
            // Start again if the target is still far off
            start_watching_heater(e);
          }
        }
  
      #endif // THERMAL_PROTECTION_HOTENDS
  
      #ifdef TEMP_SENSOR_1_AS_REDUNDANT
        if (fabs(current_temperature[0] - redundant_temperature) > MAX_REDUNDANT_TEMP_SENSOR_DIFF) {
          _temp_error(0, PSTR(MSG_EXTRUDER_SWITCHED_OFF), PSTR(MSG_ERR_REDUNDANT_TEMP));
        }
      #endif
  
    } // Extruders Loop
  
    #if HAS_AUTO_FAN
      if (ms > next_auto_fan_check_ms) { // only need to check fan state very infrequently
        checkExtruderAutoFans();
        next_auto_fan_check_ms = ms + 2500;
      }
    #endif       
  
    // Control the extruder rate based on the width sensor
    #ifdef FILAMENT_SENSOR
      if (filament_sensor) {
        meas_shift_index = delay_index1 - meas_delay_cm;
        if (meas_shift_index < 0) meas_shift_index += MAX_MEASUREMENT_DELAY + 1;  //loop around buffer if needed
        
        // Get the delayed info and add 100 to reconstitute to a percent of
        // the nominal filament diameter then square it to get an area
        meas_shift_index = constrain(meas_shift_index, 0, MAX_MEASUREMENT_DELAY);
        float vm = pow((measurement_delay[meas_shift_index] + 100.0) / 100.0, 2);
        if (vm < 0.01) vm = 0.01;
        volumetric_multiplier[FILAMENT_SENSOR_EXTRUDER_NUM] = vm;
      }
    #endif //FILAMENT_SENSOR
  
    #ifndef PIDTEMPBED
      if (ms < next_bed_check_ms) return;
      next_bed_check_ms = ms + BED_CHECK_INTERVAL;
    #endif
  
    #if TEMP_SENSOR_BED != 0
    
      #ifdef THERMAL_PROTECTION_BED
        thermal_runaway_protection(&thermal_runaway_bed_state_machine, &thermal_runaway_bed_timer, current_temperature_bed, target_temperature_bed, -1, THERMAL_PROTECTION_BED_PERIOD, THERMAL_PROTECTION_BED_HYSTERESIS);
      #endif
  
      #ifdef PIDTEMPBED
        float pid_output = get_pid_output_bed();
  
        soft_pwm_bed = current_temperature_bed > BED_MINTEMP && current_temperature_bed < BED_MAXTEMP ? (int)pid_output >> 1 : 0;
  
      #elif defined(BED_LIMIT_SWITCHING)
        // Check if temperature is within the correct band
        if (current_temperature_bed > BED_MINTEMP && current_temperature_bed < BED_MAXTEMP) {
          if (current_temperature_bed >= target_temperature_bed + BED_HYSTERESIS)
            soft_pwm_bed = 0;
          else if (current_temperature_bed <= target_temperature_bed - BED_HYSTERESIS)
            soft_pwm_bed = MAX_BED_POWER >> 1;
        }
        else {
          soft_pwm_bed = 0;
          WRITE_HEATER_BED(LOW);
        }
      #else // BED_LIMIT_SWITCHING
        // Check if temperature is within the correct range
        if (current_temperature_bed > BED_MINTEMP && current_temperature_bed < BED_MAXTEMP) {
          soft_pwm_bed = current_temperature_bed < target_temperature_bed ? MAX_BED_POWER >> 1 : 0;
        }
        else {
          soft_pwm_bed = 0;
          WRITE_HEATER_BED(LOW);
        }
      #endif
    #endif //TEMP_SENSOR_BED != 0
  }
  
  #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) {
    #ifdef TEMP_SENSOR_1_AS_REDUNDANT
      if (e > EXTRUDERS)
    #else
      if (e >= EXTRUDERS)
    #endif
      {
        SERIAL_ERROR_START;
        SERIAL_ERROR((int)e);
        SERIAL_ERRORLNPGM(MSG_INVALID_EXTRUDER_NUM);
        kill(PSTR(MSG_KILLED));
        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]);
  
      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
  }
  
  /* 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() {
    #ifdef HEATER_0_USES_MAX6675
      current_temperature_raw[0] = read_max6675();
    #endif
    for (uint8_t e = 0; e < EXTRUDERS; e++) {
      current_temperature[e] = analog2temp(current_temperature_raw[e], e);
    }
    current_temperature_bed = analog2tempBed(current_temperature_bed_raw);
    #ifdef TEMP_SENSOR_1_AS_REDUNDANT
      redundant_temperature = analog2temp(redundant_temperature_raw, 1);
    #endif
    #if HAS_FILAMENT_SENSOR
      filament_width_meas = analog2widthFil();
    #endif
    //Reset the watchdog after we know we have a temperature measurement.
    watchdog_reset();
  
    CRITICAL_SECTION_START;
    temp_meas_ready = false;
    CRITICAL_SECTION_END;
  }
  
  
  #ifdef FILAMENT_SENSOR
  
    // Convert raw Filament Width to millimeters
    float analog2widthFil() {
      return current_raw_filwidth / 16383.0 * 5.0;
      //return current_raw_filwidth;
    }
  
    // Convert raw Filament Width to a ratio
    int widthFil_to_size_ratio() {
      float temp = filament_width_meas;
      if (temp < MEASURED_LOWER_LIMIT) temp = filament_width_nominal;  //assume sensor cut out
      else if (temp > MEASURED_UPPER_LIMIT) temp = MEASURED_UPPER_LIMIT;
      return filament_width_nominal / temp * 100;
    } 
  
  #endif
  
  
  /**
   * Initialize the temperature manager
   * The manager is implemented by periodic calls to manage_heater()
   */
  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=BIT(JTD);
      MCUCR=BIT(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
        temp_iState_min[e] = 0.0;
        temp_iState_max[e] = PID_INTEGRAL_DRIVE_MAX / PID_PARAM(Ki,e);
      #endif //PIDTEMP
      #ifdef PIDTEMPBED
        temp_iState_min_bed = 0.0;
        temp_iState_max_bed = PID_BED_INTEGRAL_DRIVE_MAX / bedKi;
      #endif //PIDTEMPBED
    }
  
    #if HAS_HEATER_0
      SET_OUTPUT(HEATER_0_PIN);
    #endif
    #if HAS_HEATER_1
      SET_OUTPUT(HEATER_1_PIN);
    #endif
    #if HAS_HEATER_2
      SET_OUTPUT(HEATER_2_PIN);
    #endif
    #if HAS_HEATER_3
      SET_OUTPUT(HEATER_3_PIN);
    #endif
    #if HAS_HEATER_BED
      SET_OUTPUT(HEATER_BED_PIN);
    #endif  
    #if HAS_FAN
      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 / 2;
      #endif
    #endif
  
    #ifdef HEATER_0_USES_MAX6675
  
      #ifndef SDSUPPORT
        OUT_WRITE(SCK_PIN, LOW);
        OUT_WRITE(MOSI_PIN, HIGH);
        OUT_WRITE(MISO_PIN, HIGH);
      #else
        pinMode(SS_PIN, OUTPUT);
        digitalWrite(SS_PIN, HIGH);
      #endif
      
      OUT_WRITE(MAX6675_SS,HIGH);
  
    #endif //HEATER_0_USES_MAX6675
  
    // Set analog inputs
    
    // nothing todo for ARM
    
    // Use timer0 for temperature measurement
    // Interleave temperature interrupt with millies interrupt
    
    HAL_temp_timer_start(TEMP_TIMER_NUM);
    HAL_timer_enable_interrupt (TEMP_TIMER_NUM);
    
    // Wait for temperature measurement to settle
    delay(250);
  
    #define TEMP_MIN_ROUTINE(NR) \
      minttemp[NR] = HEATER_ ## NR ## _MINTEMP; \
      while(analog2temp(minttemp_raw[NR], NR) < HEATER_ ## NR ## _MINTEMP) { \
        if (HEATER_ ## NR ## _RAW_LO_TEMP < HEATER_ ## NR ## _RAW_HI_TEMP) \
          minttemp_raw[NR] += OVERSAMPLENR; \
        else \
          minttemp_raw[NR] -= OVERSAMPLENR; \
      }
    #define TEMP_MAX_ROUTINE(NR) \
      maxttemp[NR] = HEATER_ ## NR ## _MAXTEMP; \
      while(analog2temp(maxttemp_raw[NR], NR) > HEATER_ ## NR ## _MAXTEMP) { \
        if (HEATER_ ## NR ## _RAW_LO_TEMP < HEATER_ ## NR ## _RAW_HI_TEMP) \
          maxttemp_raw[NR] -= OVERSAMPLENR; \
        else \
          maxttemp_raw[NR] += OVERSAMPLENR; \
      }
  
    #ifdef HEATER_0_MINTEMP
      TEMP_MIN_ROUTINE(0);
    #endif
    #ifdef HEATER_0_MAXTEMP
      TEMP_MAX_ROUTINE(0);
    #endif
    #if EXTRUDERS > 1
      #ifdef HEATER_1_MINTEMP
        TEMP_MIN_ROUTINE(1);
      #endif
      #ifdef HEATER_1_MAXTEMP
        TEMP_MAX_ROUTINE(1);
      #endif
      #if EXTRUDERS > 2
        #ifdef HEATER_2_MINTEMP
          TEMP_MIN_ROUTINE(2);
        #endif
        #ifdef HEATER_2_MAXTEMP
          TEMP_MAX_ROUTINE(2);
        #endif
        #if EXTRUDERS > 3
          #ifdef HEATER_3_MINTEMP
            TEMP_MIN_ROUTINE(3);
          #endif
          #ifdef HEATER_3_MAXTEMP
            TEMP_MAX_ROUTINE(3);
          #endif
        #endif // EXTRUDERS > 3
      #endif // EXTRUDERS > 2
    #endif // EXTRUDERS > 1
  
    #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 THERMAL_PROTECTION_HOTENDS
    /**
     * Start Heating Sanity Check for hotends that are below
     * their target temperature by a configurable margin.
     * This is called when the temperature is set. (M104, M109)
     */
    void start_watching_heater(int e) {
      if (degHotend(e) < degTargetHotend(e) - (WATCH_TEMP_INCREASE + TEMP_HYSTERESIS + 1)) {
        watch_target_temp[e] = degHotend(e) + WATCH_TEMP_INCREASE;
        watch_heater_next_ms[e] = millis() + WATCH_TEMP_PERIOD * 1000;
      }
      else
        watch_heater_next_ms[e] = 0;
    }
  #endif
  
  #if defined(THERMAL_PROTECTION_HOTENDS) || defined(THERMAL_PROTECTION_BED)
  
    void thermal_runaway_protection(TRState *state, millis_t *timer, float temperature, float target_temperature, int heater_id, int period_seconds, int hysteresis_degc) {
  
      static float tr_target_temperature[EXTRUDERS+1] = { 0.0 };
  
      /*
          SERIAL_ECHO_START;
          SERIAL_ECHOPGM("Thermal Thermal Runaway Running. Heater ID: ");
          if (heater_id < 0) SERIAL_ECHOPGM("bed"); else SERIAL_ECHOPGM(heater_id);
          SERIAL_ECHOPGM(" ;  State:");
          SERIAL_ECHOPGM(*state);
          SERIAL_ECHOPGM(" ;  Timer:");
          SERIAL_ECHOPGM(*timer);
          SERIAL_ECHOPGM(" ;  Temperature:");
          SERIAL_ECHOPGM(temperature);
          SERIAL_ECHOPGM(" ;  Target Temp:");
          SERIAL_ECHOPGM(target_temperature);
          SERIAL_EOL;
      */
  
      int heater_index = heater_id >= 0 ? heater_id : EXTRUDERS;
  
      // If the target temperature changes, restart
      if (tr_target_temperature[heater_index] != target_temperature)
        *state = TRReset;
  
      switch (*state) {
        case TRReset:
          *timer = 0;
          *state = TRInactive;
        // Inactive state waits for a target temperature to be set
        case TRInactive:
          if (target_temperature > 0) {
            tr_target_temperature[heater_index] = target_temperature;
            *state = TRFirstHeating;
          }
          break;
        // When first heating, wait for the temperature to be reached then go to Stable state
        case TRFirstHeating:
          if (temperature >= tr_target_temperature[heater_index]) *state = TRStable;
          break;
        // While the temperature is stable watch for a bad temperature
        case TRStable:
          // If the temperature is over the target (-hysteresis) restart the timer
          if (temperature >= tr_target_temperature[heater_index] - hysteresis_degc)
            *timer = millis();
            // If the timer goes too long without a reset, trigger shutdown
          else if (millis() > *timer + period_seconds * 1000UL)
            *state = TRRunaway;
          break;
        case TRRunaway:
          _temp_error(heater_id, PSTR(MSG_T_THERMAL_RUNAWAY), PSTR(MSG_THERMAL_RUNAWAY));
      }
    }
  
  #endif // THERMAL_PROTECTION_HOTENDS || THERMAL_PROTECTION_BED
  
  void disable_all_heaters() {
    for (int i=0; i<EXTRUDERS; i++) setTargetHotend(0, i);
    setTargetBed(0);
  
    #define DISABLE_HEATER(NR) { \
      target_temperature[NR] = 0; \
      soft_pwm[NR] = 0; \
      WRITE_HEATER_ ## NR (LOW); \
    }
  
    #if HAS_TEMP_0
      target_temperature[0] = 0;
      soft_pwm[0] = 0;
      WRITE_HEATER_0P(LOW); // Should HEATERS_PARALLEL apply here? Then change to DISABLE_HEATER(0)
    #endif
  
    #if EXTRUDERS > 1 && HAS_TEMP_1
      DISABLE_HEATER(1);
    #endif
  
    #if EXTRUDERS > 2 && HAS_TEMP_2
      DISABLE_HEATER(2);
    #endif
  
    #if EXTRUDERS > 3 && HAS_TEMP_3
      DISABLE_HEATER(3);
    #endif
  
    #if HAS_TEMP_BED
      target_temperature_bed = 0;
      soft_pwm_bed = 0;
      #if HAS_HEATER_BED
        WRITE_HEATER_BED(LOW);
      #endif
    #endif
  }
  
  #ifdef HEATER_0_USES_MAX6675
    #define MAX6675_HEAT_INTERVAL 250u
    static millis_t next_max6675_ms = 0;
    int max6675_temp = 2000;
  
    static int read_max6675() {
  
      millis_t ms = millis();
  
      if (ms < next_max6675_ms)
        return max6675_temp;
      
      next_max6675_ms = ms + MAX6675_HEAT_INTERVAL;
  
      max6675_temp = 0;
  
      #ifdef PRR
        PRR &= ~BIT(PRSPI);
      #elif defined(PRR0)
        PRR0 &= ~BIT(PRSPI);
      #endif
  
      SPCR = BIT(MSTR) | BIT(SPE) | BIT(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 & BIT(SPIF)) == 0;);
      max6675_temp = SPDR;
      max6675_temp <<= 8;
  
      // read LSB
      SPDR = 0;
      for (;(SPSR & BIT(SPIF)) == 0;);
      max6675_temp |= SPDR;
  
      // disable TT_MAX6675
      WRITE(MAX6675_SS, 1);
  
      if (max6675_temp & 4) {
        // thermocouple open
        max6675_temp = 4000;
      }
      else {
        max6675_temp = max6675_temp >> 3;
      }
  
      return max6675_temp;
    }
  
  #endif //HEATER_0_USES_MAX6675
  
  /**
   * Stages in the ISR loop
   */
  enum TempState {
    PrepareTemp_0,
    MeasureTemp_0,
    PrepareTemp_BED,
    MeasureTemp_BED,
    PrepareTemp_1,
    MeasureTemp_1,
    PrepareTemp_2,
    MeasureTemp_2,
    PrepareTemp_3,
    MeasureTemp_3,
    Prepare_FILWIDTH,
    Measure_FILWIDTH,
    StartupDelay // Startup, delay initial temp reading a tiny bit so the hardware can settle
  };
  
  //
  // Timer 0 is shared with millies
  //
  HAL_TEMP_TIMER_ISR {
    //these variables are only accesible from the ISR, but static, so they don't lose their value
    static unsigned char temp_count = 0;
    static unsigned long raw_temp_value[4] = { 0 };
    static unsigned long raw_temp_bed_value = 0;
    static TempState temp_state = StartupDelay;
    static unsigned char pwm_count = BIT(SOFT_PWM_SCALE);
    static int max_temp[5] = { 0 };
    static int min_temp[5] = { 123000 };
    static int temp_read = 0;
  
    static unsigned char median_counter = 0;
    static unsigned long raw_median_temp[5][MEDIAN_COUNT] = { { 3950 * OVERSAMPLENR } };
    static bool first_start = true;
    // Static members for each heater
    #ifdef SLOW_PWM_HEATERS
      static unsigned char slow_pwm_count = 0;
      #define ISR_STATICS(n) \
        static unsigned char soft_pwm_ ## n; \
        static unsigned char state_heater_ ## n = 0; \
        static unsigned char state_timer_heater_ ## n = 0
    #else
      #define ISR_STATICS(n) static unsigned char soft_pwm_ ## n
    #endif
  
    // Statics per heater
    ISR_STATICS(0);
    #if (EXTRUDERS > 1) || defined(HEATERS_PARALLEL)
      ISR_STATICS(1);
      #if EXTRUDERS > 2
        ISR_STATICS(2);
        #if EXTRUDERS > 3
          ISR_STATICS(3);
        #endif
      #endif
    #endif
    #if HAS_HEATER_BED
      ISR_STATICS(BED);
    #endif
  
    #if HAS_FILAMENT_SENSOR
      static unsigned long raw_filwidth_value = 0;
    #endif
    
    // Initialize some variables only at start!
    if (first_start)
    {
      for (char i = 0; i < 5; i++)
      {
        for (int j = 0; j < MEDIAN_COUNT; j++) raw_median_temp[i][j] = 3600 * OVERSAMPLENR;
        max_temp[i] = 0;
        min_temp[i] = 123000;
      }
      first_start = false;
      SERIAL_ECHOLN("First start for temperature finished.");
    }
    
    HAL_timer_isr_status (TEMP_TIMER_COUNTER, TEMP_TIMER_CHANNEL);
    #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(1);
        }
        else WRITE_HEATER_0P(0); // If HEATERS_PARALLEL should apply, change to WRITE_HEATER_0
  
        #if EXTRUDERS > 1
          soft_pwm_1 = soft_pwm[1];
          WRITE_HEATER_1(soft_pwm_1 > 0 ? 1 : 0);
          #if EXTRUDERS > 2
            soft_pwm_2 = soft_pwm[2];
            WRITE_HEATER_2(soft_pwm_2 > 0 ? 1 : 0);
            #if EXTRUDERS > 3
              soft_pwm_3 = soft_pwm[3];
              WRITE_HEATER_3(soft_pwm_3 > 0 ? 1 : 0);
            #endif
          #endif
        #endif
  
        #if HAS_HEATER_BED
          soft_pwm_BED = soft_pwm_bed;
          WRITE_HEATER_BED(soft_pwm_BED > 0 ? 1 : 0);
        #endif
        #ifdef FAN_SOFT_PWM
          soft_pwm_fan = fanSpeedSoftPwm / 2;
          WRITE_FAN(soft_pwm_fan > 0 ? 1 : 0);
        #endif
      }
  
      if (soft_pwm_0 < pwm_count) { WRITE_HEATER_0(0); }
      #if EXTRUDERS > 1
        if (soft_pwm_1 < pwm_count) WRITE_HEATER_1(0);
        #if EXTRUDERS > 2
          if (soft_pwm_2 < pwm_count) WRITE_HEATER_2(0);
          #if EXTRUDERS > 3
            if (soft_pwm_3 < pwm_count) WRITE_HEATER_3(0);
          #endif
        #endif
      #endif
  
      #if HAS_HEATER_BED
        if (soft_pwm_BED < pwm_count) WRITE_HEATER_BED(0);
      #endif
  
      #ifdef FAN_SOFT_PWM
        if (soft_pwm_fan < pwm_count) WRITE_FAN(0);
      #endif
      
      pwm_count += BIT(SOFT_PWM_SCALE);
      pwm_count &= 0x7f;
    
    #else // 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
  
      // Macros for Slow PWM timer logic - HEATERS_PARALLEL applies
      #define _SLOW_PWM_ROUTINE(NR, src) \
        soft_pwm_ ## NR = src; \
        if (soft_pwm_ ## NR > 0) { \
          if (state_timer_heater_ ## NR == 0) { \
            if (state_heater_ ## NR == 0) state_timer_heater_ ## NR = MIN_STATE_TIME; \
            state_heater_ ## NR = 1; \
            WRITE_HEATER_ ## NR(1); \
          } \
        } \
        else { \
          if (state_timer_heater_ ## NR == 0) { \
            if (state_heater_ ## NR == 1) state_timer_heater_ ## NR = MIN_STATE_TIME; \
            state_heater_ ## NR = 0; \
            WRITE_HEATER_ ## NR(0); \
          } \
        }
      #define SLOW_PWM_ROUTINE(n) _SLOW_PWM_ROUTINE(n, soft_pwm[n])
  
      #define PWM_OFF_ROUTINE(NR) \
        if (soft_pwm_ ## NR < slow_pwm_count) { \
          if (state_timer_heater_ ## NR == 0) { \
            if (state_heater_ ## NR == 1) state_timer_heater_ ## NR = MIN_STATE_TIME; \
            state_heater_ ## NR = 0; \
            WRITE_HEATER_ ## NR (0); \
          } \
        }
  
      if (slow_pwm_count == 0) {
  
        SLOW_PWM_ROUTINE(0); // EXTRUDER 0
        #if EXTRUDERS > 1
          SLOW_PWM_ROUTINE(1); // EXTRUDER 1
          #if EXTRUDERS > 2
            SLOW_PWM_ROUTINE(2); // EXTRUDER 2
            #if EXTRUDERS > 3
              SLOW_PWM_ROUTINE(3); // EXTRUDER 3
            #endif
          #endif
        #endif
        #if HAS_HEATER_BED
          _SLOW_PWM_ROUTINE(BED, soft_pwm_bed); // BED
        #endif
  
      } // slow_pwm_count == 0
  
      PWM_OFF_ROUTINE(0); // EXTRUDER 0
      #if EXTRUDERS > 1
        PWM_OFF_ROUTINE(1); // EXTRUDER 1
        #if EXTRUDERS > 2
          PWM_OFF_ROUTINE(2); // EXTRUDER 2
          #if EXTRUDERS > 3
            PWM_OFF_ROUTINE(3); // EXTRUDER 3
          #endif
        #endif
      #endif
      #if HAS_HEATER_BED
        PWM_OFF_ROUTINE(BED); // BED
      #endif
  
      #ifdef FAN_SOFT_PWM
        if (pwm_count == 0) {
          soft_pwm_fan = fanSpeedSoftPwm / 2;
          WRITE_FAN(soft_pwm_fan > 0 ? 1 : 0);
        }
        if (soft_pwm_fan < pwm_count) WRITE_FAN(0);
      #endif //FAN_SOFT_PWM
  
      pwm_count += BIT(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--;
          #if EXTRUDERS > 2    // EXTRUDER 2
            if (state_timer_heater_2 > 0) state_timer_heater_2--;
            #if EXTRUDERS > 3    // EXTRUDER 3
              if (state_timer_heater_3 > 0) state_timer_heater_3--;
            #endif
          #endif
        #endif
        #if HAS_HEATER_BED
          if (state_timer_heater_BED > 0) state_timer_heater_BED--;
        #endif
      } // (pwm_count % 64) == 0
    
    #endif // SLOW_PWM_HEATERS
  
    #define START_TEMP(temp_id) startAdcConversion(pinToAdcChannel(TEMP_## temp_id ##_PIN))
    #define START_BED_TEMP() startAdcConversion(pinToAdcChannel(TEMP_BED_PIN))
    
    #define READ_TEMP(temp_id) temp_read = getAdcReading(pinToAdcChannel(TEMP_## temp_id ##_PIN)); \
      raw_temp_value[temp_id] += temp_read; \
      max_temp[temp_id] = max(max_temp[temp_id], temp_read); \
      min_temp[temp_id] = min(min_temp[temp_id], temp_read)
      
    #define READ_BED_TEMP(temp_id) temp_read = getAdcReading(pinToAdcChannel(TEMP_BED_PIN)); \
      raw_temp_bed_value += temp_read; \
      max_temp[temp_id] = max(max_temp[temp_id], temp_read); \
      min_temp[temp_id] = min(min_temp[temp_id], temp_read)
  
    // Prepare or measure a sensor, each one every 12th frame
    switch(temp_state) {
      case PrepareTemp_0:
        #if HAS_TEMP_0
          START_TEMP(0);
        #endif
        lcd_buttons_update();
        temp_state = MeasureTemp_0;
        break;
      case MeasureTemp_0:
        #if HAS_TEMP_0
          READ_TEMP(0);
        #endif
        temp_state = PrepareTemp_BED;
        break;
  
      case PrepareTemp_BED:
        #if HAS_TEMP_BED
          START_BED_TEMP();
        #endif
        lcd_buttons_update();
        temp_state = MeasureTemp_BED;
        break;
      case MeasureTemp_BED:
        #if HAS_TEMP_BED
          READ_BED_TEMP(4);
        #endif
        temp_state = PrepareTemp_1;
        break;
  
      case PrepareTemp_1:
        #if HAS_TEMP_1
          START_TEMP(1)
        #endif
        lcd_buttons_update();
        temp_state = MeasureTemp_1;
        break;
      case MeasureTemp_1:
        #if HAS_TEMP_1
          READ_TEMP(1);
        #endif
        temp_state = PrepareTemp_2;
        break;
  
      case PrepareTemp_2:
        #if HAS_TEMP_2
          START_TEMP(2)
        #endif
        lcd_buttons_update();
        temp_state = MeasureTemp_2;
        break;
      case MeasureTemp_2:
        #if HAS_TEMP_2
          READ_TEMP(2);
        #endif
        temp_state = PrepareTemp_3;
        break;
  
      case PrepareTemp_3:
        #if HAS_TEMP_3
          START_TEMP(3)
        #endif
        lcd_buttons_update();
        temp_state = MeasureTemp_3;
        break;
      case MeasureTemp_3:
        #if HAS_TEMP_3
          READ_TEMP(3)
        #endif
        temp_state = Prepare_FILWIDTH;
        break;
  
      case Prepare_FILWIDTH:
        #if HAS_FILAMENT_SENSOR
        // nothing todo for Due
        #endif
        lcd_buttons_update();
        temp_state = Measure_FILWIDTH;
        break;
      case Measure_FILWIDTH:
        #if HAS_FILAMENT_SENSOR
          // raw_filwidth_value += ADC;  //remove to use an IIR filter approach
          if (ADC > 102) { //check that ADC is reading a voltage > 0.5 volts, otherwise don't take in the data.
            raw_filwidth_value -= (raw_filwidth_value>>7);  //multiply raw_filwidth_value by 127/128
            raw_filwidth_value += ((unsigned long)ADC<<7);  //add new ADC reading
          }
        #endif
        temp_state = PrepareTemp_0;
        temp_count++;
        break;
  
      case StartupDelay:
        temp_state = PrepareTemp_0;
        analogReadResolution(12); //  ADC need some rework
        break;
  
      // default:
      //   SERIAL_ERROR_START;
      //   SERIAL_ERRORLNPGM("Temp measurement error!");
      //   break;
    } // switch(temp_state)
  
    #define SET_CURRENT_TEMP_RAW(temp_id) raw_median_temp[temp_id][median_counter] = (raw_temp_value[temp_id] - (min_temp[temp_id] + max_temp[temp_id])); \
      sum = 0; \
      for(int i = 0; i < MEDIAN_COUNT; i++) sum += raw_median_temp[temp_id][i]; \
      current_temperature_raw[temp_id] = (sum / MEDIAN_COUNT + 4) >> 2
        
    #define SET_CURRENT_BED_RAW(temp_id) raw_median_temp[temp_id][median_counter] = (raw_temp_bed_value - (min_temp[temp_id] + max_temp[temp_id])); \
      sum = 0; \
      for(int i = 0; i < MEDIAN_COUNT; i++) sum += raw_median_temp[temp_id][i]; \
      current_temperature_bed_raw = (sum / MEDIAN_COUNT + 4) >> 2
      
    #define SET_REDUNDANT_RAW(temp_id) raw_median_temp[temp_id][median_counter] = (raw_temp_bed_value - (min_temp[temp_id] + max_temp[temp_id])); \
      sum = 0; \
      for(int i = 0; i < MEDIAN_COUNT; i++) sum += raw_median_temp[temp_id][i]; \
      redundant_temperature_raw = (sum / MEDIAN_COUNT + 4) >> 2
    
    if(temp_count >= OVERSAMPLENR + 2) { // 10 * 16 * 1/(16000000/64/256)  = 164ms.
      if (!temp_meas_ready) { //Only update the raw values if they have been read. Else we could be updating them during reading.
        unsigned long sum = 0;
        #ifndef HEATER_0_USES_MAX6675
          SET_CURRENT_TEMP_RAW(0);
        #endif
        #if EXTRUDERS > 1
          SET_CURRENT_TEMP_RAW(1);
          #if EXTRUDERS > 2
            SET_CURRENT_TEMP_RAW(2);
            #if EXTRUDERS > 3
              SET_CURRENT_TEMP_RAW(3);
            #endif
          #endif
        #endif
        #ifdef TEMP_SENSOR_1_AS_REDUNDANT
          SET_REDUNDANT_RAW(1);
        #endif
        SET_CURRENT_BED_RAW(4);
        
        //  Reset min/max-holder
        for (char i = 0; i < 5; i++) {
          max_temp[i] = 0;
          min_temp[i] = 123000;
        }
      } //!temp_meas_ready
  
      // Filament Sensor - can be read any time since IIR filtering is used
      #if HAS_FILAMENT_SENSOR
        current_raw_filwidth = raw_filwidth_value >> 10;  // Divide to get to 0-16384 range since we used 1/128 IIR filter approach
      #endif
  
      median_counter++;
      if (median_counter >= MEDIAN_COUNT) median_counter = 0;
  
      temp_meas_ready = true;
      temp_count = 0;
      for (int i = 0; i < 4; i++) raw_temp_value[i] = 0;
      raw_temp_bed_value = 0;
  
      #if HAS_TEMP_0 && !defined(HEATER_0_USES_MAX6675)
        #if HEATER_0_RAW_LO_TEMP > HEATER_0_RAW_HI_TEMP
          #define GE0 <=
        #else
          #define GE0 >=
        #endif
        if (current_temperature_raw[0] GE0 maxttemp_raw[0]) max_temp_error(0);
        if (minttemp_raw[0] GE0 current_temperature_raw[0]) min_temp_error(0);
      #endif
  
      #if HAS_TEMP_1
        #if HEATER_1_RAW_LO_TEMP > HEATER_1_RAW_HI_TEMP
          #define GE1 <=
        #else
          #define GE1 >=
        #endif
        if (current_temperature_raw[1] GE1 maxttemp_raw[1]) max_temp_error(1);
        if (minttemp_raw[1] GE1 current_temperature_raw[1]) min_temp_error(1);
      #endif // TEMP_SENSOR_1
  
      #if HAS_TEMP_2
        #if HEATER_2_RAW_LO_TEMP > HEATER_2_RAW_HI_TEMP
          #define GE2 <=
        #else
          #define GE2 >=
        #endif
        if (current_temperature_raw[2] GE2 maxttemp_raw[2]) max_temp_error(2);
        if (minttemp_raw[2] GE2 current_temperature_raw[2]) min_temp_error(2);
      #endif // TEMP_SENSOR_2
  
      #if HAS_TEMP_3
        #if HEATER_3_RAW_LO_TEMP > HEATER_3_RAW_HI_TEMP
          #define GE3 <=
        #else
          #define GE3 >=
        #endif
        if (current_temperature_raw[3] GE3 maxttemp_raw[3]) max_temp_error(3);
        if (minttemp_raw[3] GE3 current_temperature_raw[3]) min_temp_error(3);
      #endif // TEMP_SENSOR_3
  
      #if HAS_TEMP_BED
        #if HEATER_BED_RAW_LO_TEMP > HEATER_BED_RAW_HI_TEMP
          #define GEBED <=
        #else
          #define GEBED >=
        #endif
        if (current_temperature_bed_raw GEBED bed_maxttemp_raw) _temp_error(-1, PSTR(MSG_T_MAXTEMP), PSTR(MSG_ERR_MAXTEMP_BED));
        if (bed_minttemp_raw GEBED current_temperature_bed_raw) _temp_error(-1, PSTR(MSG_T_MINTEMP), PSTR(MSG_ERR_MINTEMP_BED));
      #endif
  
    } // temp_count >= OVERSAMPLENR
  
    #ifdef BABYSTEPPING
      for (uint8_t axis = X_AXIS; axis <= Z_AXIS; axis++) {
        int curTodo = babystepsTodo[axis]; //get rid of volatile for performance
       
        if (curTodo > 0) {
          babystep(axis,/*fwd*/true);
          babystepsTodo[axis]--; //fewer to do next time
        }
        else if (curTodo < 0) {
          babystep(axis,/*fwd*/false);
          babystepsTodo[axis]++; //fewer to do next time
        }
      }
    #endif //BABYSTEPPING
  }
  
  #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
  