scube/Marlin/Marlin_main.cpp

/* -*- c++ -*- */

/*
    Reprap firmware based on Sprinter and grbl.
 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"

#ifdef ENABLE_AUTO_BED_LEVELING
#include "vector_3.h"
  #ifdef AUTO_BED_LEVELING_GRID
    #include "qr_solve.h"
  #endif
#endif // ENABLE_AUTO_BED_LEVELING

#include "ultralcd.h"
#include "planner.h"
#include "stepper.h"
#include "temperature.h"
#include "motion_control.h"
#include "cardreader.h"
#include "watchdog.h"
#include "ConfigurationStore.h"
#include "language.h"
#include "pins_arduino.h"
#include "math.h"

#ifdef BLINKM
  #include "BlinkM.h"
  #include "Wire.h"
#endif

#if NUM_SERVOS > 0
  #include "Servo.h"
#endif

#if defined(DIGIPOTSS_PIN) && DIGIPOTSS_PIN > -1
  #include <SPI.h>
#endif

// look here for descriptions of G-codes: http://linuxcnc.org/handbook/gcode/g-code.html
// http://objects.reprap.org/wiki/Mendel_User_Manual:_RepRapGCodes

//Implemented Codes
//-------------------
// G0  -> G1
// G1  - Coordinated Movement X Y Z E
// G2  - CW ARC
// G3  - CCW ARC
// G4  - Dwell S<seconds> or P<milliseconds>
// G10 - retract filament according to settings of M207
// G11 - retract recover filament according to settings of M208
// G28 - Home all Axis
// G29 - Detailed Z-Probe, probes the bed at 3 or more points.  Will fail if you haven't homed yet.
// G30 - Single Z Probe, probes bed at current XY location.
// G31 - Dock sled (Z_PROBE_SLED only)
// G32 - Undock sled (Z_PROBE_SLED only)
// G90 - Use Absolute Coordinates
// G91 - Use Relative Coordinates
// G92 - Set current position to coordinates given

// M Codes
// M0   - Unconditional stop - Wait for user to press a button on the LCD (Only if ULTRA_LCD is enabled)
// M1   - Same as M0
// M17  - Enable/Power all stepper motors
// M18  - Disable all stepper motors; same as M84
// M20  - List SD card
// M21  - Init SD card
// M22  - Release SD card
// M23  - Select SD file (M23 filename.g)
// M24  - Start/resume SD print
// M25  - Pause SD print
// M26  - Set SD position in bytes (M26 S12345)
// M27  - Report SD print status
// M28  - Start SD write (M28 filename.g)
// M29  - Stop SD write
// M30  - Delete file from SD (M30 filename.g)
// M31  - Output time since last M109 or SD card start to serial
// M32  - Select file and start SD print (Can be used _while_ printing from SD card files):
//        syntax "M32 /path/filename#", or "M32 S<startpos bytes> !filename#"
//        Call gcode file : "M32 P !filename#" and return to caller file after finishing (similar to #include).
//        The '#' is necessary when calling from within sd files, as it stops buffer prereading
// M42  - Change pin status via gcode Use M42 Px Sy to set pin x to value y, when omitting Px the onboard led will be used.
// M80  - Turn on Power Supply
// M81  - Turn off Power Supply
// M82  - Set E codes absolute (default)
// M83  - Set E codes relative while in Absolute Coordinates (G90) mode
// M84  - Disable steppers until next move,
//        or use S<seconds> to specify an inactivity timeout, after which the steppers will be disabled.  S0 to disable the timeout.
// M85  - Set inactivity shutdown timer with parameter S<seconds>. To disable set zero (default)
// M92  - Set axis_steps_per_unit - same syntax as G92
// M104 - Set extruder target temp
// M105 - Read current temp
// M106 - Fan on
// M107 - Fan off
// M109 - Sxxx Wait for extruder current temp to reach target temp. Waits only when heating
//        Rxxx Wait for extruder current temp to reach target temp. Waits when heating and cooling
//        IF AUTOTEMP is enabled, S<mintemp> B<maxtemp> F<factor>. Exit autotemp by any M109 without F
// M112 - Emergency stop
// M114 - Output current position to serial port
// M115 - Capabilities string
// M117 - display message
// M119 - Output Endstop status to serial port
// M126 - Solenoid Air Valve Open (BariCUDA support by jmil)
// M127 - Solenoid Air Valve Closed (BariCUDA vent to atmospheric pressure by jmil)
// M128 - EtoP Open (BariCUDA EtoP = electricity to air pressure transducer by jmil)
// M129 - EtoP Closed (BariCUDA EtoP = electricity to air pressure transducer by jmil)
// M140 - Set bed target temp
// M150 - Set BlinkM Color Output R: Red<0-255> U(!): Green<0-255> B: Blue<0-255> over i2c, G for green does not work.
// M190 - Sxxx Wait for bed current temp to reach target temp. Waits only when heating
//        Rxxx Wait for bed current temp to reach target temp. Waits when heating and cooling
// M200 D<millimeters>- set filament diameter and set E axis units to cubic millimeters (use S0 to set back to millimeters).
// M201 - Set max acceleration in units/s^2 for print moves (M201 X1000 Y1000)
// M202 - Set max acceleration in units/s^2 for travel moves (M202 X1000 Y1000) Unused in Marlin!!
// M203 - Set maximum feedrate that your machine can sustain (M203 X200 Y200 Z300 E10000) in mm/sec
// M204 - Set default acceleration: S normal moves T filament only moves (M204 S3000 T7000) in mm/sec^2  also sets minimum segment time in ms (B20000) to prevent buffer under-runs and M20 minimum feedrate
// M205 -  advanced settings:  minimum travel speed S=while printing T=travel only,  B=minimum segment time X= maximum xy jerk, Z=maximum Z jerk, E=maximum E jerk
// M206 - Set additional homing offset
// M207 - Set retract length S[positive mm] F[feedrate mm/min] Z[additional zlift/hop], stays in mm regardless of M200 setting
// M208 - Set recover=unretract length S[positive mm surplus to the M207 S*] F[feedrate mm/sec]
// M209 - S<1=true/0=false> enable automatic retract detect if the slicer did not support G10/11: every normal extrude-only move will be classified as retract depending on the direction.
// M218 - Set hotend offset (in mm): T<extruder_number> X<offset_on_X> Y<offset_on_Y>
// M220 S<factor in percent>- set speed factor override percentage
// M221 S<factor in percent>- set extrude factor override percentage
// M226 P<pin number> S<pin state>- Wait until the specified pin reaches the state required
// M240 - Trigger a camera to take a photograph
// M250 - Set LCD contrast C<contrast value> (value 0..63)
// M280 - Set servo position absolute. P: servo index, S: angle or microseconds
// M300 - Play beep sound S<frequency Hz> P<duration ms>
// M301 - Set PID parameters P I and D
// M302 - Allow cold extrudes, or set the minimum extrude S<temperature>.
// M303 - PID relay autotune S<temperature> sets the target temperature. (default target temperature = 150C)
// M304 - Set bed PID parameters P I and D
// M380 - Activate solenoid on active extruder
// M381 - Disable all solenoids
// M400 - Finish all moves
// M401 - Lower z-probe if present
// M402 - Raise z-probe if present
// M404 - N<dia in mm> Enter the nominal filament width (3mm, 1.75mm ) or will display nominal filament width without parameters
// M405 - Turn on Filament Sensor extrusion control.  Optional D<delay in cm> to set delay in centimeters between sensor and extruder 
// M406 - Turn off Filament Sensor extrusion control 
// M407 - Displays measured filament diameter 
// M500 - Store parameters in EEPROM
// M501 - Read parameters from EEPROM (if you need reset them after you changed them temporarily).
// M502 - Revert to the default "factory settings".  You still need to store them in EEPROM afterwards if you want to.
// M503 - Print the current settings (from memory not from EEPROM). Use S0 to leave off headings.
// M540 - Use S[0|1] to enable or disable the stop SD card print on endstop hit (requires ABORT_ON_ENDSTOP_HIT_FEATURE_ENABLED)
// M600 - Pause for filament change X[pos] Y[pos] Z[relative lift] E[initial retract] L[later retract distance for removal]
// M665 - Set delta configurations
// M666 - Set delta endstop adjustment
// M605 - Set dual x-carriage movement mode: S<mode> [ X<duplication x-offset> R<duplication temp offset> ]
// M907 - Set digital trimpot motor current using axis codes.
// M908 - Control digital trimpot directly.
// M350 - Set microstepping mode.
// M351 - Toggle MS1 MS2 pins directly.

// ************ SCARA Specific - This can change to suit future G-code regulations
// M360 - SCARA calibration: Move to cal-position ThetaA (0 deg calibration)
// M361 - SCARA calibration: Move to cal-position ThetaB (90 deg calibration - steps per degree)
// M362 - SCARA calibration: Move to cal-position PsiA (0 deg calibration)
// M363 - SCARA calibration: Move to cal-position PsiB (90 deg calibration - steps per degree)
// M364 - SCARA calibration: Move to cal-position PSIC (90 deg to Theta calibration position)
// M365 - SCARA calibration: Scaling factor, X, Y, Z axis
//************* SCARA End ***************

// M928 - Start SD logging (M928 filename.g) - ended by M29
// M999 - Restart after being stopped by error

#ifdef SDSUPPORT
  CardReader card;
#endif

float homing_feedrate[] = HOMING_FEEDRATE;
bool axis_relative_modes[] = AXIS_RELATIVE_MODES;
int feedmultiply = 100; //100->1 200->2
int saved_feedmultiply;
int extrudemultiply = 100; //100->1 200->2
int extruder_multiply[EXTRUDERS] = { 100
  #if EXTRUDERS > 1
    , 100
    #if EXTRUDERS > 2
      , 100
	    #if EXTRUDERS > 3
      	, 100
	    #endif
    #endif
  #endif
};
bool volumetric_enabled = false;
float filament_size[EXTRUDERS] = { DEFAULT_NOMINAL_FILAMENT_DIA
  #if EXTRUDERS > 1
      , DEFAULT_NOMINAL_FILAMENT_DIA
    #if EXTRUDERS > 2
       , DEFAULT_NOMINAL_FILAMENT_DIA
      #if EXTRUDERS > 3
        , DEFAULT_NOMINAL_FILAMENT_DIA
      #endif
    #endif
  #endif
};
float volumetric_multiplier[EXTRUDERS] = {1.0
  #if EXTRUDERS > 1
    , 1.0
    #if EXTRUDERS > 2
      , 1.0
      #if EXTRUDERS > 3
        , 1.0
      #endif
    #endif
  #endif
};
float current_position[NUM_AXIS] = { 0.0, 0.0, 0.0, 0.0 };
float add_homing[3] = { 0, 0, 0 };
#ifdef DELTA
  float endstop_adj[3] = { 0, 0, 0 };
#endif

float min_pos[3] = { X_MIN_POS, Y_MIN_POS, Z_MIN_POS };
float max_pos[3] = { X_MAX_POS, Y_MAX_POS, Z_MAX_POS };
bool axis_known_position[3] = { false, false, false };
float zprobe_zoffset;

// Extruder offset
#if EXTRUDERS > 1
#ifndef DUAL_X_CARRIAGE
  #define NUM_EXTRUDER_OFFSETS 2 // only in XY plane
#else
  #define NUM_EXTRUDER_OFFSETS 3 // supports offsets in XYZ plane
#endif
float extruder_offset[NUM_EXTRUDER_OFFSETS][EXTRUDERS] = {
  #if defined(EXTRUDER_OFFSET_X)
    EXTRUDER_OFFSET_X
  #else
    0
  #endif
  ,
  #if defined(EXTRUDER_OFFSET_Y)
    EXTRUDER_OFFSET_Y
  #else
    0
  #endif
};
#endif

uint8_t active_extruder = 0;
int fanSpeed = 0;

#ifdef SERVO_ENDSTOPS
  int servo_endstops[] = SERVO_ENDSTOPS;
  int servo_endstop_angles[] = SERVO_ENDSTOP_ANGLES;
#endif

#ifdef BARICUDA
  int ValvePressure = 0;
  int EtoPPressure = 0;
#endif

#ifdef FWRETRACT

  bool autoretract_enabled = false;
  bool retracted[EXTRUDERS] = { false
    #if EXTRUDERS > 1
      , false
      #if EXTRUDERS > 2
        , false
        #if EXTRUDERS > 3
       	  , false
      	#endif
      #endif
    #endif
  };
  bool retracted_swap[EXTRUDERS] = { false
    #if EXTRUDERS > 1
      , false
      #if EXTRUDERS > 2
        , false
        #if EXTRUDERS > 3
       	  , false
      	#endif
      #endif
    #endif
  };

  float retract_length = RETRACT_LENGTH;
  float retract_length_swap = RETRACT_LENGTH_SWAP;
  float retract_feedrate = RETRACT_FEEDRATE;
  float retract_zlift = RETRACT_ZLIFT;
  float retract_recover_length = RETRACT_RECOVER_LENGTH;
  float retract_recover_length_swap = RETRACT_RECOVER_LENGTH_SWAP;
  float retract_recover_feedrate = RETRACT_RECOVER_FEEDRATE;

#endif // FWRETRACT

#ifdef ULTIPANEL
  bool powersupply = 
    #ifdef PS_DEFAULT_OFF
      false
    #else
  	  true
    #endif
  ;
#endif

#ifdef DELTA
  float delta[3] = { 0, 0, 0 };
  #define SIN_60 0.8660254037844386
  #define COS_60 0.5
  // these are the default values, can be overriden with M665
  float delta_radius = DELTA_RADIUS;
  float delta_tower1_x = -SIN_60 * delta_radius; // front left tower
  float delta_tower1_y = -COS_60 * delta_radius;	   
  float delta_tower2_x =  SIN_60 * delta_radius; // front right tower
  float delta_tower2_y = -COS_60 * delta_radius;	   
  float delta_tower3_x = 0;                      // back middle tower
  float delta_tower3_y = delta_radius;
  float delta_diagonal_rod = DELTA_DIAGONAL_ROD;
  float delta_diagonal_rod_2 = sq(delta_diagonal_rod);
  float delta_segments_per_second = DELTA_SEGMENTS_PER_SECOND;
#endif

#ifdef SCARA
  float axis_scaling[3] = { 1, 1, 1 };    // Build size scaling, default to 1
#endif				

bool cancel_heatup = false;

#ifdef FILAMENT_SENSOR
  //Variables for Filament Sensor input 
  float filament_width_nominal=DEFAULT_NOMINAL_FILAMENT_DIA;  //Set nominal filament width, can be changed with M404 
  bool filament_sensor=false;  //M405 turns on filament_sensor control, M406 turns it off 
  float filament_width_meas=DEFAULT_MEASURED_FILAMENT_DIA; //Stores the measured filament diameter 
  signed char measurement_delay[MAX_MEASUREMENT_DELAY+1];  //ring buffer to delay measurement  store extruder factor after subtracting 100 
  int delay_index1=0;  //index into ring buffer
  int delay_index2=-1;  //index into ring buffer - set to -1 on startup to indicate ring buffer needs to be initialized
  float delay_dist=0; //delay distance counter  
  int meas_delay_cm = MEASUREMENT_DELAY_CM;  //distance delay setting
#endif

const char errormagic[] PROGMEM = "Error:";
const char echomagic[] PROGMEM = "echo:";

const char axis_codes[NUM_AXIS] = {'X', 'Y', 'Z', 'E'};
static float destination[NUM_AXIS] = { 0, 0, 0, 0 };

#ifndef DELTA
  static float delta[3] = { 0, 0, 0 };
#endif

static float offset[3] = { 0, 0, 0 };
static bool home_all_axis = true;
static float feedrate = 1500.0, next_feedrate, saved_feedrate;
static long gcode_N, gcode_LastN, Stopped_gcode_LastN = 0;

static bool relative_mode = false;  //Determines Absolute or Relative Coordinates

static char cmdbuffer[BUFSIZE][MAX_CMD_SIZE];
static bool fromsd[BUFSIZE];
static int bufindr = 0;
static int bufindw = 0;
static int buflen = 0;

static char serial_char;
static int serial_count = 0;
static boolean comment_mode = false;
static char *strchr_pointer; ///< A pointer to find chars in the command string (X, Y, Z, E, etc.)

const char* queued_commands_P= NULL; /* pointer to the current line in the active sequence of commands, or NULL when none */

const int sensitive_pins[] = SENSITIVE_PINS; ///< Sensitive pin list for M42

// Inactivity shutdown
static unsigned long previous_millis_cmd = 0;
static unsigned long max_inactive_time = 0;
static unsigned long stepper_inactive_time = DEFAULT_STEPPER_DEACTIVE_TIME*1000l;

unsigned long starttime = 0; ///< Print job start time
unsigned long stoptime = 0;  ///< Print job stop time

static uint8_t tmp_extruder;


bool Stopped = false;

#if NUM_SERVOS > 0
  Servo servos[NUM_SERVOS];
#endif

bool CooldownNoWait = true;
bool target_direction;

#ifdef CHDK
  unsigned long chdkHigh = 0;
  boolean chdkActive = false;
#endif

//===========================================================================
//=============================Routines======================================
//===========================================================================

void get_arc_coordinates();
bool setTargetedHotend(int code);

void serial_echopair_P(const char *s_P, float v)
    { serialprintPGM(s_P); SERIAL_ECHO(v); }
void serial_echopair_P(const char *s_P, double v)
    { serialprintPGM(s_P); SERIAL_ECHO(v); }
void serial_echopair_P(const char *s_P, unsigned long v)
    { serialprintPGM(s_P); SERIAL_ECHO(v); }

#ifdef SDSUPPORT
  #include "SdFatUtil.h"
  int freeMemory() { return SdFatUtil::FreeRam(); }
#else
  extern "C" {
    extern unsigned int __bss_end;
    extern unsigned int __heap_start;
    extern void *__brkval;

    int freeMemory() {
      int free_memory;

      if ((int)__brkval == 0)
        free_memory = ((int)&free_memory) - ((int)&__bss_end);
      else
        free_memory = ((int)&free_memory) - ((int)__brkval);

      return free_memory;
    }
  }
#endif //!SDSUPPORT

//Injects the next command from the pending sequence of commands, when possible
//Return false if and only if no command was pending
static bool drain_queued_commands_P()
{
  char cmd[30];
  if(!queued_commands_P)
    return false;
  // Get the next 30 chars from the sequence of gcodes to run
  strncpy_P(cmd, queued_commands_P, sizeof(cmd)-1);
  cmd[sizeof(cmd)-1]= 0;
  // Look for the end of line, or the end of sequence
  size_t i= 0;
  char c;
  while( (c= cmd[i]) && c!='\n' )
    ++i; // look for the end of this gcode command
  cmd[i]= 0;
  if(enquecommand(cmd)) // buffer was not full (else we will retry later)
  {
    if(c)
      queued_commands_P+= i+1; // move to next command
    else
      queued_commands_P= NULL; // will have no more commands in the sequence
  }
  return true;
}

//Record one or many commands to run from program memory.
//Aborts the current queue, if any.
//Note: drain_queued_commands_P() must be called repeatedly to drain the commands afterwards
void enquecommands_P(const char* pgcode)
{
    queued_commands_P= pgcode;
    drain_queued_commands_P(); // first command exectuted asap (when possible)
}

//adds a single command to the main command buffer, from RAM
//that is really done in a non-safe way.
//needs overworking someday
//Returns false if it failed to do so
bool enquecommand(const char *cmd)
{
  if(*cmd==';')
    return false;
  if(buflen >= BUFSIZE)
    return false;
  //this is dangerous if a mixing of serial and this happens
  strcpy(&(cmdbuffer[bufindw][0]),cmd);
  SERIAL_ECHO_START;
  SERIAL_ECHOPGM(MSG_Enqueing);
  SERIAL_ECHO(cmdbuffer[bufindw]);
  SERIAL_ECHOLNPGM("\"");
  bufindw= (bufindw + 1)%BUFSIZE;
  buflen += 1;
  return true;
}



void setup_killpin()
{
  #if defined(KILL_PIN) && KILL_PIN > -1
    SET_INPUT(KILL_PIN);
    WRITE(KILL_PIN,HIGH);
  #endif
}

// Set home pin
void setup_homepin(void)
{
#if defined(HOME_PIN) && HOME_PIN > -1
   SET_INPUT(HOME_PIN);
   WRITE(HOME_PIN,HIGH);
#endif
}


void setup_photpin()
{
  #if defined(PHOTOGRAPH_PIN) && PHOTOGRAPH_PIN > -1
    OUT_WRITE(PHOTOGRAPH_PIN, LOW);
  #endif
}

void setup_powerhold()
{
  #if defined(SUICIDE_PIN) && SUICIDE_PIN > -1
    OUT_WRITE(SUICIDE_PIN, HIGH);
  #endif
  #if defined(PS_ON_PIN) && PS_ON_PIN > -1
    #if defined(PS_DEFAULT_OFF)
      OUT_WRITE(PS_ON_PIN, PS_ON_ASLEEP);
      #else
      OUT_WRITE(PS_ON_PIN, PS_ON_AWAKE);
    #endif
  #endif
}

void suicide()
{
  #if defined(SUICIDE_PIN) && SUICIDE_PIN > -1
    OUT_WRITE(SUICIDE_PIN, LOW);
  #endif
}

void servo_init()
{
  #if (NUM_SERVOS >= 1) && defined(SERVO0_PIN) && (SERVO0_PIN > -1)
    servos[0].attach(SERVO0_PIN);
  #endif
  #if (NUM_SERVOS >= 2) && defined(SERVO1_PIN) && (SERVO1_PIN > -1)
    servos[1].attach(SERVO1_PIN);
  #endif
  #if (NUM_SERVOS >= 3) && defined(SERVO2_PIN) && (SERVO2_PIN > -1)
    servos[2].attach(SERVO2_PIN);
  #endif
  #if (NUM_SERVOS >= 4) && defined(SERVO3_PIN) && (SERVO3_PIN > -1)
    servos[3].attach(SERVO3_PIN);
  #endif
  #if (NUM_SERVOS >= 5)
    #error "TODO: enter initalisation code for more servos"
  #endif

  // Set position of Servo Endstops that are defined
  #ifdef SERVO_ENDSTOPS
  for(int8_t i = 0; i < 3; i++)
  {
    if(servo_endstops[i] > -1) {
      servos[servo_endstops[i]].write(servo_endstop_angles[i * 2 + 1]);
    }
  }
  #endif

  #if defined (ENABLE_AUTO_BED_LEVELING) && (PROBE_SERVO_DEACTIVATION_DELAY > 0)
  delay(PROBE_SERVO_DEACTIVATION_DELAY);
  servos[servo_endstops[Z_AXIS]].detach();
  #endif
}


void setup()
{
  setup_killpin();
  setup_powerhold();
  MYSERIAL.begin(BAUDRATE);
  SERIAL_PROTOCOLLNPGM("start");
  SERIAL_ECHO_START;

  // Check startup - does nothing if bootloader sets MCUSR to 0
  byte mcu = MCUSR;
  if(mcu & 1) SERIAL_ECHOLNPGM(MSG_POWERUP);
  if(mcu & 2) SERIAL_ECHOLNPGM(MSG_EXTERNAL_RESET);
  if(mcu & 4) SERIAL_ECHOLNPGM(MSG_BROWNOUT_RESET);
  if(mcu & 8) SERIAL_ECHOLNPGM(MSG_WATCHDOG_RESET);
  if(mcu & 32) SERIAL_ECHOLNPGM(MSG_SOFTWARE_RESET);
  MCUSR=0;

  SERIAL_ECHOPGM(MSG_MARLIN);
  SERIAL_ECHOLNPGM(STRING_VERSION);
  #ifdef STRING_VERSION_CONFIG_H
    #ifdef STRING_CONFIG_H_AUTHOR
      SERIAL_ECHO_START;
      SERIAL_ECHOPGM(MSG_CONFIGURATION_VER);
      SERIAL_ECHOPGM(STRING_VERSION_CONFIG_H);
      SERIAL_ECHOPGM(MSG_AUTHOR);
      SERIAL_ECHOLNPGM(STRING_CONFIG_H_AUTHOR);
      SERIAL_ECHOPGM("Compiled: ");
      SERIAL_ECHOLNPGM(__DATE__);
    #endif // STRING_CONFIG_H_AUTHOR
  #endif // STRING_VERSION_CONFIG_H
  SERIAL_ECHO_START;
  SERIAL_ECHOPGM(MSG_FREE_MEMORY);
  SERIAL_ECHO(freeMemory());
  SERIAL_ECHOPGM(MSG_PLANNER_BUFFER_BYTES);
  SERIAL_ECHOLN((int)sizeof(block_t)*BLOCK_BUFFER_SIZE);
  for(int8_t i = 0; i < BUFSIZE; i++)
  {
    fromsd[i] = false;
  }

  // loads data from EEPROM if available else uses defaults (and resets step acceleration rate)
  Config_RetrieveSettings();

  tp_init();    // Initialize temperature loop
  plan_init();  // Initialize planner;
  watchdog_init();
  st_init();    // Initialize stepper, this enables interrupts!
  setup_photpin();
  servo_init();
  

  lcd_init();
  _delay_ms(1000);	// wait 1sec to display the splash screen

  #if defined(CONTROLLERFAN_PIN) && CONTROLLERFAN_PIN > -1
    SET_OUTPUT(CONTROLLERFAN_PIN); //Set pin used for driver cooling fan
  #endif

  #ifdef DIGIPOT_I2C
    digipot_i2c_init();
  #endif
#ifdef Z_PROBE_SLED
  pinMode(SERVO0_PIN, OUTPUT);
  digitalWrite(SERVO0_PIN, LOW); // turn it off
#endif // Z_PROBE_SLED
  setup_homepin();
  
#ifdef STAT_LED_RED
  pinMode(STAT_LED_RED, OUTPUT);
  digitalWrite(STAT_LED_RED, LOW); // turn it off
#endif
#ifdef STAT_LED_BLUE
  pinMode(STAT_LED_BLUE, OUTPUT);
  digitalWrite(STAT_LED_BLUE, LOW); // turn it off
#endif  
}


void loop()
{
  if(buflen < (BUFSIZE-1))
    get_command();
  #ifdef SDSUPPORT
  card.checkautostart(false);
  #endif
  if(buflen)
  {
    #ifdef SDSUPPORT
      if(card.saving)
      {
        if(strstr_P(cmdbuffer[bufindr], PSTR("M29")) == NULL)
        {
          card.write_command(cmdbuffer[bufindr]);
          if(card.logging)
          {
            process_commands();
          }
          else
          {
            SERIAL_PROTOCOLLNPGM(MSG_OK);
          }
        }
        else
        {
          card.closefile();
          SERIAL_PROTOCOLLNPGM(MSG_FILE_SAVED);
        }
      }
      else
      {
        process_commands();
      }
    #else
      process_commands();
    #endif //SDSUPPORT
    buflen = (buflen-1);
    bufindr = (bufindr + 1)%BUFSIZE;
  }
  //check heater every n milliseconds
  manage_heater();
  manage_inactivity();
  checkHitEndstops();
  lcd_update();
}

void get_command()
{
  if(drain_queued_commands_P()) // priority is given to non-serial commands
    return;
  
  while( MYSERIAL.available() > 0  && buflen < BUFSIZE) {
    serial_char = MYSERIAL.read();
    if(serial_char == '\n' ||
       serial_char == '\r' ||
       (serial_char == ':' && comment_mode == false) ||
       serial_count >= (MAX_CMD_SIZE - 1) )
    {
      if(!serial_count) { //if empty line
        comment_mode = false; //for new command
        return;
      }
      cmdbuffer[bufindw][serial_count] = 0; //terminate string
      if(!comment_mode){
        comment_mode = false; //for new command
        fromsd[bufindw] = false;
        if(strchr(cmdbuffer[bufindw], 'N') != NULL)
        {
          strchr_pointer = strchr(cmdbuffer[bufindw], 'N');
          gcode_N = (strtol(&cmdbuffer[bufindw][strchr_pointer - cmdbuffer[bufindw] + 1], NULL, 10));
          if(gcode_N != gcode_LastN+1 && (strstr_P(cmdbuffer[bufindw], PSTR("M110")) == NULL) ) {
            SERIAL_ERROR_START;
            SERIAL_ERRORPGM(MSG_ERR_LINE_NO);
            SERIAL_ERRORLN(gcode_LastN);
            //Serial.println(gcode_N);
            FlushSerialRequestResend();
            serial_count = 0;
            return;
          }

          if(strchr(cmdbuffer[bufindw], '*') != NULL)
          {
            byte checksum = 0;
            byte count = 0;
            while(cmdbuffer[bufindw][count] != '*') checksum = checksum^cmdbuffer[bufindw][count++];
            strchr_pointer = strchr(cmdbuffer[bufindw], '*');

            if( (int)(strtod(&cmdbuffer[bufindw][strchr_pointer - cmdbuffer[bufindw] + 1], NULL)) != checksum) {
              SERIAL_ERROR_START;
              SERIAL_ERRORPGM(MSG_ERR_CHECKSUM_MISMATCH);
              SERIAL_ERRORLN(gcode_LastN);
              FlushSerialRequestResend();
              serial_count = 0;
              return;
            }
            //if no errors, continue parsing
          }
          else
          {
            SERIAL_ERROR_START;
            SERIAL_ERRORPGM(MSG_ERR_NO_CHECKSUM);
            SERIAL_ERRORLN(gcode_LastN);
            FlushSerialRequestResend();
            serial_count = 0;
            return;
          }

          gcode_LastN = gcode_N;
          //if no errors, continue parsing
        }
        else  // if we don't receive 'N' but still see '*'
        {
          if((strchr(cmdbuffer[bufindw], '*') != NULL))
          {
            SERIAL_ERROR_START;
            SERIAL_ERRORPGM(MSG_ERR_NO_LINENUMBER_WITH_CHECKSUM);
            SERIAL_ERRORLN(gcode_LastN);
            serial_count = 0;
            return;
          }
        }
        if((strchr(cmdbuffer[bufindw], 'G') != NULL)){
          strchr_pointer = strchr(cmdbuffer[bufindw], 'G');
          switch((int)((strtod(&cmdbuffer[bufindw][strchr_pointer - cmdbuffer[bufindw] + 1], NULL)))){
          case 0:
          case 1:
          case 2:
          case 3:
            if (Stopped == true) {
              SERIAL_ERRORLNPGM(MSG_ERR_STOPPED);
              LCD_MESSAGEPGM(MSG_STOPPED);
            }
            break;
          default:
            break;
          }

        }

        //If command was e-stop process now
        if(strcmp(cmdbuffer[bufindw], "M112") == 0)
          kill();
        
        bufindw = (bufindw + 1)%BUFSIZE;
        buflen += 1;
      }
      serial_count = 0; //clear buffer
    }
    else
    {
      if(serial_char == ';') comment_mode = true;
      if(!comment_mode) cmdbuffer[bufindw][serial_count++] = serial_char;
    }
  }
  #ifdef SDSUPPORT
  if(!card.sdprinting || serial_count!=0){
    return;
  }

  //'#' stops reading from SD to the buffer prematurely, so procedural macro calls are possible
  // if it occurs, stop_buffering is triggered and the buffer is ran dry.
  // this character _can_ occur in serial com, due to checksums. however, no checksums are used in SD printing

  static bool stop_buffering=false;
  if(buflen==0) stop_buffering=false;

  while( !card.eof()  && buflen < BUFSIZE && !stop_buffering) {
    int16_t n=card.get();
    serial_char = (char)n;
    if(serial_char == '\n' ||
       serial_char == '\r' ||
       (serial_char == '#' && comment_mode == false) ||
       (serial_char == ':' && comment_mode == false) ||
       serial_count >= (MAX_CMD_SIZE - 1)||n==-1)
    {
      if(card.eof()){
        SERIAL_PROTOCOLLNPGM(MSG_FILE_PRINTED);
        stoptime=millis();
        char time[30];
        unsigned long t=(stoptime-starttime)/1000;
        int hours, minutes;
        minutes=(t/60)%60;
        hours=t/60/60;
        sprintf_P(time, PSTR("%i hours %i minutes"),hours, minutes);
        SERIAL_ECHO_START;
        SERIAL_ECHOLN(time);
        lcd_setstatus(time);
        card.printingHasFinished();
        card.checkautostart(true);

      }
      if(serial_char=='#')
        stop_buffering=true;

      if(!serial_count)
      {
        comment_mode = false; //for new command
        return; //if empty line
      }
      cmdbuffer[bufindw][serial_count] = 0; //terminate string
//      if(!comment_mode){
        fromsd[bufindw] = true;
        buflen += 1;
        bufindw = (bufindw + 1)%BUFSIZE;
//      }
      comment_mode = false; //for new command
      serial_count = 0; //clear buffer
    }
    else
    {
      if(serial_char == ';') comment_mode = true;
      if(!comment_mode) cmdbuffer[bufindw][serial_count++] = serial_char;
    }
  }

  #endif //SDSUPPORT

}


float code_value()
{
  return (strtod(&cmdbuffer[bufindr][strchr_pointer - cmdbuffer[bufindr] + 1], NULL));
}

long code_value_long()
{
  return (strtol(&cmdbuffer[bufindr][strchr_pointer - cmdbuffer[bufindr] + 1], NULL, 10));
}

bool code_seen(char code)
{
  strchr_pointer = strchr(cmdbuffer[bufindr], code);
  return (strchr_pointer != NULL);  //Return True if a character was found
}

#define DEFINE_PGM_READ_ANY(type, reader)       \
    static inline type pgm_read_any(const type *p)  \
    { return pgm_read_##reader##_near(p); }

DEFINE_PGM_READ_ANY(float,       float);
DEFINE_PGM_READ_ANY(signed char, byte);

#define XYZ_CONSTS_FROM_CONFIG(type, array, CONFIG) \
static const PROGMEM type array##_P[3] =        \
    { X_##CONFIG, Y_##CONFIG, Z_##CONFIG };     \
static inline type array(int axis)          \
    { return pgm_read_any(&array##_P[axis]); }

XYZ_CONSTS_FROM_CONFIG(float, base_min_pos,    MIN_POS);
XYZ_CONSTS_FROM_CONFIG(float, base_max_pos,    MAX_POS);
XYZ_CONSTS_FROM_CONFIG(float, base_home_pos,   HOME_POS);
XYZ_CONSTS_FROM_CONFIG(float, max_length,      MAX_LENGTH);
XYZ_CONSTS_FROM_CONFIG(float, home_retract_mm, HOME_RETRACT_MM);
XYZ_CONSTS_FROM_CONFIG(signed char, home_dir,  HOME_DIR);

#ifdef DUAL_X_CARRIAGE
  #if EXTRUDERS == 1 || defined(COREXY) \
      || !defined(X2_ENABLE_PIN) || !defined(X2_STEP_PIN) || !defined(X2_DIR_PIN) \
      || !defined(X2_HOME_POS) || !defined(X2_MIN_POS) || !defined(X2_MAX_POS) \
      || !defined(X_MAX_PIN) || X_MAX_PIN < 0
    #error "Missing or invalid definitions for DUAL_X_CARRIAGE mode."
  #endif
  #if X_HOME_DIR != -1 || X2_HOME_DIR != 1
    #error "Please use canonical x-carriage assignment" // the x-carriages are defined by their homing directions
  #endif

#define DXC_FULL_CONTROL_MODE 0
#define DXC_AUTO_PARK_MODE    1
#define DXC_DUPLICATION_MODE  2
static int dual_x_carriage_mode = DEFAULT_DUAL_X_CARRIAGE_MODE;

static float x_home_pos(int extruder) {
  if (extruder == 0)
    return base_home_pos(X_AXIS) + add_homing[X_AXIS];
  else
    // In dual carriage mode the extruder offset provides an override of the
    // second X-carriage offset when homed - otherwise X2_HOME_POS is used.
    // This allow soft recalibration of the second extruder offset position without firmware reflash
    // (through the M218 command).
    return (extruder_offset[X_AXIS][1] > 0) ? extruder_offset[X_AXIS][1] : X2_HOME_POS;
}

static int x_home_dir(int extruder) {
  return (extruder == 0) ? X_HOME_DIR : X2_HOME_DIR;
}

static float inactive_extruder_x_pos = X2_MAX_POS; // used in mode 0 & 1
static bool active_extruder_parked = false; // used in mode 1 & 2
static float raised_parked_position[NUM_AXIS]; // used in mode 1
static unsigned long delayed_move_time = 0; // used in mode 1
static float duplicate_extruder_x_offset = DEFAULT_DUPLICATION_X_OFFSET; // used in mode 2
static float duplicate_extruder_temp_offset = 0; // used in mode 2
bool extruder_duplication_enabled = false; // used in mode 2
#endif //DUAL_X_CARRIAGE

static void axis_is_at_home(int axis) {
#ifdef DUAL_X_CARRIAGE
  if (axis == X_AXIS) {
    if (active_extruder != 0) {
      current_position[X_AXIS] = x_home_pos(active_extruder);
      min_pos[X_AXIS] =          X2_MIN_POS;
      max_pos[X_AXIS] =          max(extruder_offset[X_AXIS][1], X2_MAX_POS);
      return;
    }
    else if (dual_x_carriage_mode == DXC_DUPLICATION_MODE && active_extruder == 0) {
      current_position[X_AXIS] = base_home_pos(X_AXIS) + add_homing[X_AXIS];
      min_pos[X_AXIS] =          base_min_pos(X_AXIS) + add_homing[X_AXIS];
      max_pos[X_AXIS] =          min(base_max_pos(X_AXIS) + add_homing[X_AXIS],
                                  max(extruder_offset[X_AXIS][1], X2_MAX_POS) - duplicate_extruder_x_offset);
      return;
    }
  }
#endif
#ifdef SCARA
   float homeposition[3];
   char i;
   
   if (axis < 2)
   {
   
     for (i=0; i<3; i++)
     {
        homeposition[i] = base_home_pos(i); 
     }  
	// SERIAL_ECHOPGM("homeposition[x]= "); SERIAL_ECHO(homeposition[0]);
   //  SERIAL_ECHOPGM("homeposition[y]= "); SERIAL_ECHOLN(homeposition[1]);
   // Works out real Homeposition angles using inverse kinematics, 
   // and calculates homing offset using forward kinematics
     calculate_delta(homeposition);
     
    // SERIAL_ECHOPGM("base Theta= "); SERIAL_ECHO(delta[X_AXIS]);
    // SERIAL_ECHOPGM(" base Psi+Theta="); SERIAL_ECHOLN(delta[Y_AXIS]);
     
     for (i=0; i<2; i++)
     {
        delta[i] -= add_homing[i];
     } 
     
    // SERIAL_ECHOPGM("addhome X="); SERIAL_ECHO(add_homing[X_AXIS]);
	// SERIAL_ECHOPGM(" addhome Y="); SERIAL_ECHO(add_homing[Y_AXIS]);
    // SERIAL_ECHOPGM(" addhome Theta="); SERIAL_ECHO(delta[X_AXIS]);
    // SERIAL_ECHOPGM(" addhome Psi+Theta="); SERIAL_ECHOLN(delta[Y_AXIS]);
      
     calculate_SCARA_forward_Transform(delta);
     
    // SERIAL_ECHOPGM("Delta X="); SERIAL_ECHO(delta[X_AXIS]);
    // SERIAL_ECHOPGM(" Delta Y="); SERIAL_ECHOLN(delta[Y_AXIS]);
     
    current_position[axis] = delta[axis];
    
    // SCARA home positions are based on configuration since the actual limits are determined by the 
    // inverse kinematic transform.
    min_pos[axis] =          base_min_pos(axis); // + (delta[axis] - base_home_pos(axis));
    max_pos[axis] =          base_max_pos(axis); // + (delta[axis] - base_home_pos(axis));
   } 
   else
   {
      current_position[axis] = base_home_pos(axis) + add_homing[axis];
      min_pos[axis] =          base_min_pos(axis) + add_homing[axis];
      max_pos[axis] =          base_max_pos(axis) + add_homing[axis];
   }
#else
  current_position[axis] = base_home_pos(axis) + add_homing[axis];
  min_pos[axis] =          base_min_pos(axis) + add_homing[axis];
  max_pos[axis] =          base_max_pos(axis) + add_homing[axis];
#endif
}

#ifdef ENABLE_AUTO_BED_LEVELING
#ifdef AUTO_BED_LEVELING_GRID
static void set_bed_level_equation_lsq(double *plane_equation_coefficients)
{
    vector_3 planeNormal = vector_3(-plane_equation_coefficients[0], -plane_equation_coefficients[1], 1);
    planeNormal.debug("planeNormal");
    plan_bed_level_matrix = matrix_3x3::create_look_at(planeNormal);
    //bedLevel.debug("bedLevel");

    //plan_bed_level_matrix.debug("bed level before");
    //vector_3 uncorrected_position = plan_get_position_mm();
    //uncorrected_position.debug("position before");

    vector_3 corrected_position = plan_get_position();
//    corrected_position.debug("position after");
    current_position[X_AXIS] = corrected_position.x;
    current_position[Y_AXIS] = corrected_position.y;
    current_position[Z_AXIS] = corrected_position.z;

    // put the bed at 0 so we don't go below it.
    current_position[Z_AXIS] = zprobe_zoffset; // in the lsq we reach here after raising the extruder due to the loop structure

    plan_set_position(current_position[X_AXIS], current_position[Y_AXIS], current_position[Z_AXIS], current_position[E_AXIS]);
}

#else // not AUTO_BED_LEVELING_GRID

static void set_bed_level_equation_3pts(float z_at_pt_1, float z_at_pt_2, float z_at_pt_3) {

    plan_bed_level_matrix.set_to_identity();

    vector_3 pt1 = vector_3(ABL_PROBE_PT_1_X, ABL_PROBE_PT_1_Y, z_at_pt_1);
    vector_3 pt2 = vector_3(ABL_PROBE_PT_2_X, ABL_PROBE_PT_2_Y, z_at_pt_2);
    vector_3 pt3 = vector_3(ABL_PROBE_PT_3_X, ABL_PROBE_PT_3_Y, z_at_pt_3);

    vector_3 from_2_to_1 = (pt1 - pt2).get_normal();
    vector_3 from_2_to_3 = (pt3 - pt2).get_normal();
    vector_3 planeNormal = vector_3::cross(from_2_to_1, from_2_to_3).get_normal();
    planeNormal = vector_3(planeNormal.x, planeNormal.y, abs(planeNormal.z));

    plan_bed_level_matrix = matrix_3x3::create_look_at(planeNormal);

    vector_3 corrected_position = plan_get_position();
    current_position[X_AXIS] = corrected_position.x;
    current_position[Y_AXIS] = corrected_position.y;
    current_position[Z_AXIS] = corrected_position.z;

    // put the bed at 0 so we don't go below it.
    current_position[Z_AXIS] = zprobe_zoffset;

    plan_set_position(current_position[X_AXIS], current_position[Y_AXIS], current_position[Z_AXIS], current_position[E_AXIS]);

}

#endif // AUTO_BED_LEVELING_GRID

static void run_z_probe() {
    plan_bed_level_matrix.set_to_identity();
    feedrate = homing_feedrate[Z_AXIS];

    // move down until you find the bed
    float zPosition = -10;
    plan_buffer_line(current_position[X_AXIS], current_position[Y_AXIS], zPosition, current_position[E_AXIS], feedrate/60, active_extruder);
    st_synchronize();

        // we have to let the planner know where we are right now as it is not where we said to go.
    zPosition = st_get_position_mm(Z_AXIS);
    plan_set_position(current_position[X_AXIS], current_position[Y_AXIS], zPosition, current_position[E_AXIS]);

    // move up the retract distance
    zPosition += home_retract_mm(Z_AXIS);
    plan_buffer_line(current_position[X_AXIS], current_position[Y_AXIS], zPosition, current_position[E_AXIS], feedrate/60, active_extruder);
    st_synchronize();

    // move back down slowly to find bed
    feedrate = homing_feedrate[Z_AXIS]/4;
    zPosition -= home_retract_mm(Z_AXIS) * 2;
    plan_buffer_line(current_position[X_AXIS], current_position[Y_AXIS], zPosition, current_position[E_AXIS], feedrate/60, active_extruder);
    st_synchronize();

    current_position[Z_AXIS] = st_get_position_mm(Z_AXIS);
    // make sure the planner knows where we are as it may be a bit different than we last said to move to
    plan_set_position(current_position[X_AXIS], current_position[Y_AXIS], current_position[Z_AXIS], current_position[E_AXIS]);
}

static void do_blocking_move_to(float x, float y, float z) {
    float oldFeedRate = feedrate;

    feedrate = homing_feedrate[Z_AXIS];

    current_position[Z_AXIS] = z;
    plan_buffer_line(current_position[X_AXIS], current_position[Y_AXIS], current_position[Z_AXIS], current_position[E_AXIS], feedrate/60, active_extruder);
    st_synchronize();

    feedrate = XY_TRAVEL_SPEED;

    current_position[X_AXIS] = x;
    current_position[Y_AXIS] = y;
    plan_buffer_line(current_position[X_AXIS], current_position[Y_AXIS], current_position[Z_AXIS], current_position[E_AXIS], feedrate/60, active_extruder);
    st_synchronize();

    feedrate = oldFeedRate;
}

static void do_blocking_move_relative(float offset_x, float offset_y, float offset_z) {
    do_blocking_move_to(current_position[X_AXIS] + offset_x, current_position[Y_AXIS] + offset_y, current_position[Z_AXIS] + offset_z);
}

static void setup_for_endstop_move() {
    saved_feedrate = feedrate;
    saved_feedmultiply = feedmultiply;
    feedmultiply = 100;
    previous_millis_cmd = millis();

    enable_endstops(true);
}

static void clean_up_after_endstop_move() {
#ifdef ENDSTOPS_ONLY_FOR_HOMING
    enable_endstops(false);
#endif

    feedrate = saved_feedrate;
    feedmultiply = saved_feedmultiply;
    previous_millis_cmd = millis();
}

static void engage_z_probe() {
    // Engage Z Servo endstop if enabled
    #ifdef SERVO_ENDSTOPS
    if (servo_endstops[Z_AXIS] > -1) {
#if defined (ENABLE_AUTO_BED_LEVELING) && (PROBE_SERVO_DEACTIVATION_DELAY > 0)
        servos[servo_endstops[Z_AXIS]].attach(0);
#endif
        servos[servo_endstops[Z_AXIS]].write(servo_endstop_angles[Z_AXIS * 2]);
#if defined (ENABLE_AUTO_BED_LEVELING) && (PROBE_SERVO_DEACTIVATION_DELAY > 0)
        delay(PROBE_SERVO_DEACTIVATION_DELAY);
        servos[servo_endstops[Z_AXIS]].detach();
#endif
    }
    #endif
}

static void retract_z_probe() {
    // Retract Z Servo endstop if enabled
    #ifdef SERVO_ENDSTOPS
    if (servo_endstops[Z_AXIS] > -1) {
#if defined (ENABLE_AUTO_BED_LEVELING) && (PROBE_SERVO_DEACTIVATION_DELAY > 0)
        servos[servo_endstops[Z_AXIS]].attach(0);
#endif
        servos[servo_endstops[Z_AXIS]].write(servo_endstop_angles[Z_AXIS * 2 + 1]);
#if defined (ENABLE_AUTO_BED_LEVELING) && (PROBE_SERVO_DEACTIVATION_DELAY > 0)
        delay(PROBE_SERVO_DEACTIVATION_DELAY);
        servos[servo_endstops[Z_AXIS]].detach();
#endif
    }
    #endif
}

/// Probe bed height at position (x,y), returns the measured z value
static float probe_pt(float x, float y, float z_before, int retract_action=0) {
  // move to right place
  do_blocking_move_to(current_position[X_AXIS], current_position[Y_AXIS], z_before);
  do_blocking_move_to(x - X_PROBE_OFFSET_FROM_EXTRUDER, y - Y_PROBE_OFFSET_FROM_EXTRUDER, current_position[Z_AXIS]);

#ifndef Z_PROBE_SLED
   if ((retract_action==0) || (retract_action==1)) 
     engage_z_probe();   // Engage Z Servo endstop if available
#endif // Z_PROBE_SLED
  run_z_probe();
  float measured_z = current_position[Z_AXIS];
#ifndef Z_PROBE_SLED
  if ((retract_action==0) || (retract_action==3)) 
     retract_z_probe();
#endif // Z_PROBE_SLED

  SERIAL_PROTOCOLPGM(MSG_BED);
  SERIAL_PROTOCOLPGM(" x: ");
  SERIAL_PROTOCOL(x);
  SERIAL_PROTOCOLPGM(" y: ");
  SERIAL_PROTOCOL(y);
  SERIAL_PROTOCOLPGM(" z: ");
  SERIAL_PROTOCOL(measured_z);
  SERIAL_PROTOCOLPGM("\n");
  return measured_z;
}

#endif // #ifdef ENABLE_AUTO_BED_LEVELING

static void homeaxis(int axis) {
#define HOMEAXIS_DO(LETTER) \
  ((LETTER##_MIN_PIN > -1 && LETTER##_HOME_DIR==-1) || (LETTER##_MAX_PIN > -1 && LETTER##_HOME_DIR==1))

  if (axis==X_AXIS ? HOMEAXIS_DO(X) :
      axis==Y_AXIS ? HOMEAXIS_DO(Y) :
      axis==Z_AXIS ? HOMEAXIS_DO(Z) :
      0) {
    int axis_home_dir = home_dir(axis);
#ifdef DUAL_X_CARRIAGE
    if (axis == X_AXIS)
      axis_home_dir = x_home_dir(active_extruder);
#endif

    current_position[axis] = 0;
    plan_set_position(current_position[X_AXIS], current_position[Y_AXIS], current_position[Z_AXIS], current_position[E_AXIS]);


#ifndef Z_PROBE_SLED
    // Engage Servo endstop if enabled
    #ifdef SERVO_ENDSTOPS
      #if defined (ENABLE_AUTO_BED_LEVELING) && (PROBE_SERVO_DEACTIVATION_DELAY > 0)
        if (axis==Z_AXIS) {
          engage_z_probe();
        }
	    else
      #endif
      if (servo_endstops[axis] > -1) {
        servos[servo_endstops[axis]].write(servo_endstop_angles[axis * 2]);
      }
    #endif
#endif // Z_PROBE_SLED
    destination[axis] = 1.5 * max_length(axis) * axis_home_dir;
    feedrate = homing_feedrate[axis];
    plan_buffer_line(destination[X_AXIS], destination[Y_AXIS], destination[Z_AXIS], destination[E_AXIS], feedrate/60, active_extruder);
    st_synchronize();

    current_position[axis] = 0;
    plan_set_position(current_position[X_AXIS], current_position[Y_AXIS], current_position[Z_AXIS], current_position[E_AXIS]);
    destination[axis] = -home_retract_mm(axis) * axis_home_dir;
    plan_buffer_line(destination[X_AXIS], destination[Y_AXIS], destination[Z_AXIS], destination[E_AXIS], feedrate/60, active_extruder);
    st_synchronize();

    destination[axis] = 2*home_retract_mm(axis) * axis_home_dir;
#ifdef DELTA
    feedrate = homing_feedrate[axis]/10;
#else
    feedrate = homing_feedrate[axis]/2 ;
#endif
    plan_buffer_line(destination[X_AXIS], destination[Y_AXIS], destination[Z_AXIS], destination[E_AXIS], feedrate/60, active_extruder);
    st_synchronize();
#ifdef DELTA
    // retrace by the amount specified in endstop_adj
    if (endstop_adj[axis] * axis_home_dir < 0) {
      plan_set_position(current_position[X_AXIS], current_position[Y_AXIS], current_position[Z_AXIS], current_position[E_AXIS]);
      destination[axis] = endstop_adj[axis];
      plan_buffer_line(destination[X_AXIS], destination[Y_AXIS], destination[Z_AXIS], destination[E_AXIS], feedrate/60, active_extruder);
      st_synchronize();
    }
#endif
    axis_is_at_home(axis);
    destination[axis] = current_position[axis];
    feedrate = 0.0;
    endstops_hit_on_purpose();
    axis_known_position[axis] = true;

    // Retract Servo endstop if enabled
    #ifdef SERVO_ENDSTOPS
      if (servo_endstops[axis] > -1) {
        servos[servo_endstops[axis]].write(servo_endstop_angles[axis * 2 + 1]);
      }
    #endif
#if defined (ENABLE_AUTO_BED_LEVELING) && (PROBE_SERVO_DEACTIVATION_DELAY > 0)
  #ifndef Z_PROBE_SLED
    if (axis==Z_AXIS) retract_z_probe();
  #endif
#endif

  }
}
#define HOMEAXIS(LETTER) homeaxis(LETTER##_AXIS)

void refresh_cmd_timeout(void)
{
  previous_millis_cmd = millis();
}

#ifdef FWRETRACT
  void retract(bool retracting, bool swapretract = false) {
    if(retracting && !retracted[active_extruder]) {
      destination[X_AXIS]=current_position[X_AXIS];
      destination[Y_AXIS]=current_position[Y_AXIS];
      destination[Z_AXIS]=current_position[Z_AXIS];
      destination[E_AXIS]=current_position[E_AXIS];
      if (swapretract) {
        current_position[E_AXIS]+=retract_length_swap/volumetric_multiplier[active_extruder];
      } else {
        current_position[E_AXIS]+=retract_length/volumetric_multiplier[active_extruder];
      }
      plan_set_e_position(current_position[E_AXIS]);
      float oldFeedrate = feedrate;
      feedrate=retract_feedrate*60;
      retracted[active_extruder]=true;
      prepare_move();
      if(retract_zlift > 0.01) {
         current_position[Z_AXIS]-=retract_zlift;
#ifdef DELTA
         calculate_delta(current_position); // change cartesian kinematic to  delta kinematic;
         plan_set_position(delta[X_AXIS], delta[Y_AXIS], delta[Z_AXIS], current_position[E_AXIS]);
#else
         plan_set_position(current_position[X_AXIS], current_position[Y_AXIS], current_position[Z_AXIS], current_position[E_AXIS]);
#endif
         prepare_move();
      }
      feedrate = oldFeedrate;
    } else if(!retracting && retracted[active_extruder]) {
      destination[X_AXIS]=current_position[X_AXIS];
      destination[Y_AXIS]=current_position[Y_AXIS];
      destination[Z_AXIS]=current_position[Z_AXIS];
      destination[E_AXIS]=current_position[E_AXIS];
      if(retract_zlift > 0.01) {
         current_position[Z_AXIS]+=retract_zlift;
#ifdef DELTA
         calculate_delta(current_position); // change cartesian kinematic  to  delta kinematic;
         plan_set_position(delta[X_AXIS], delta[Y_AXIS], delta[Z_AXIS], current_position[E_AXIS]);
#else
         plan_set_position(current_position[X_AXIS], current_position[Y_AXIS], current_position[Z_AXIS], current_position[E_AXIS]);
#endif
         //prepare_move();
      }
      if (swapretract) {
        current_position[E_AXIS]-=(retract_length_swap+retract_recover_length_swap)/volumetric_multiplier[active_extruder]; 
      } else {
        current_position[E_AXIS]-=(retract_length+retract_recover_length)/volumetric_multiplier[active_extruder]; 
      }
      plan_set_e_position(current_position[E_AXIS]);
      float oldFeedrate = feedrate;
      feedrate=retract_recover_feedrate*60;
      retracted[active_extruder]=false;
      prepare_move();
      feedrate = oldFeedrate;
    }
  } //retract
#endif //FWRETRACT

#ifdef Z_PROBE_SLED
//
// Method to dock/undock a sled designed by Charles Bell.
//
// dock[in]     If true, move to MAX_X and engage the electromagnet
// offset[in]   The additional distance to move to adjust docking location
//
static void dock_sled(bool dock, int offset=0) {
 int z_loc;
 
 if (!((axis_known_position[X_AXIS]) && (axis_known_position[Y_AXIS]))) {
   LCD_MESSAGEPGM(MSG_POSITION_UNKNOWN);
   SERIAL_ECHO_START;
   SERIAL_ECHOLNPGM(MSG_POSITION_UNKNOWN);
   return;
 }

 if (dock) {
   do_blocking_move_to(X_MAX_POS + SLED_DOCKING_OFFSET + offset,
                       current_position[Y_AXIS],
                       current_position[Z_AXIS]);
   // turn off magnet
   digitalWrite(SERVO0_PIN, LOW);
 } else {
   if (current_position[Z_AXIS] < (Z_RAISE_BEFORE_PROBING + 5))
     z_loc = Z_RAISE_BEFORE_PROBING;
   else
     z_loc = current_position[Z_AXIS];
   do_blocking_move_to(X_MAX_POS + SLED_DOCKING_OFFSET + offset,
                       Y_PROBE_OFFSET_FROM_EXTRUDER, z_loc);
   // turn on magnet
   digitalWrite(SERVO0_PIN, HIGH);
 }
}
#endif

void process_commands()
{
  unsigned long codenum; //throw away variable
  char *starpos = NULL;
#ifdef ENABLE_AUTO_BED_LEVELING
  float x_tmp, y_tmp, z_tmp, real_z;
#endif
  if(code_seen('G'))
  {
    switch((int)code_value())
    {
    case 0: // G0 -> G1
    case 1: // G1
      if(Stopped == false) {
        get_coordinates(); // For X Y Z E F
          #ifdef FWRETRACT
            if(autoretract_enabled)
            if( !(code_seen('X') || code_seen('Y') || code_seen('Z')) && code_seen('E')) {
              float echange=destination[E_AXIS]-current_position[E_AXIS];
              if((echange<-MIN_RETRACT && !retracted[active_extruder]) || (echange>MIN_RETRACT && retracted[active_extruder])) { //move appears to be an attempt to retract or recover
                  current_position[E_AXIS] = destination[E_AXIS]; //hide the slicer-generated retract/recover from calculations
                  plan_set_e_position(current_position[E_AXIS]); //AND from the planner
                  retract(!retracted[active_extruder]);
                  return;
              }
            }
          #endif //FWRETRACT
        prepare_move();
        //ClearToSend();
      }
      break;
#ifndef SCARA //disable arc support
    case 2: // G2  - CW ARC
      if(Stopped == false) {
        get_arc_coordinates();
        prepare_arc_move(true);
      }
      break;
    case 3: // G3  - CCW ARC
      if(Stopped == false) {
        get_arc_coordinates();
        prepare_arc_move(false);
      }
      break;
#endif
    case 4: // G4 dwell
      LCD_MESSAGEPGM(MSG_DWELL);
      codenum = 0;
      if(code_seen('P')) codenum = code_value(); // milliseconds to wait
      if(code_seen('S')) codenum = code_value() * 1000; // seconds to wait

      st_synchronize();
      codenum += millis();  // keep track of when we started waiting
      previous_millis_cmd = millis();
      while(millis() < codenum) {
        manage_heater();
        manage_inactivity();
        lcd_update();
      }
      break;
      #ifdef FWRETRACT
      case 10: // G10 retract
       #if EXTRUDERS > 1
        retracted_swap[active_extruder]=(code_seen('S') && code_value_long() == 1); // checks for swap retract argument
        retract(true,retracted_swap[active_extruder]);
       #else
        retract(true);
       #endif
      break;
      case 11: // G11 retract_recover
       #if EXTRUDERS > 1
        retract(false,retracted_swap[active_extruder]);
       #else
        retract(false);
       #endif 
      break;
      #endif //FWRETRACT
    case 28: //G28 Home all Axis one at a time
#ifdef ENABLE_AUTO_BED_LEVELING
      plan_bed_level_matrix.set_to_identity();  //Reset the plane ("erase" all leveling data)
#endif //ENABLE_AUTO_BED_LEVELING

      saved_feedrate = feedrate;
      saved_feedmultiply = feedmultiply;
      feedmultiply = 100;
      previous_millis_cmd = millis();

      enable_endstops(true);

      for(int8_t i=0; i < NUM_AXIS; i++) {
        destination[i] = current_position[i];
      }
      feedrate = 0.0;

#ifdef DELTA
          // A delta can only safely home all axis at the same time
          // all axis have to home at the same time

          // Move all carriages up together until the first endstop is hit.
          current_position[X_AXIS] = 0;
          current_position[Y_AXIS] = 0;
          current_position[Z_AXIS] = 0;
          plan_set_position(current_position[X_AXIS], current_position[Y_AXIS], current_position[Z_AXIS], current_position[E_AXIS]);

          destination[X_AXIS] = 3 * Z_MAX_LENGTH;
          destination[Y_AXIS] = 3 * Z_MAX_LENGTH;
          destination[Z_AXIS] = 3 * Z_MAX_LENGTH;
          feedrate = 1.732 * homing_feedrate[X_AXIS];
          plan_buffer_line(destination[X_AXIS], destination[Y_AXIS], destination[Z_AXIS], destination[E_AXIS], feedrate/60, active_extruder);
          st_synchronize();
          endstops_hit_on_purpose();

          current_position[X_AXIS] = destination[X_AXIS];
          current_position[Y_AXIS] = destination[Y_AXIS];
          current_position[Z_AXIS] = destination[Z_AXIS];

          // take care of back off and rehome now we are all at the top
          HOMEAXIS(X);
          HOMEAXIS(Y);
          HOMEAXIS(Z);

          calculate_delta(current_position);
          plan_set_position(delta[X_AXIS], delta[Y_AXIS], delta[Z_AXIS], current_position[E_AXIS]);

#else // NOT DELTA

      home_all_axis = !((code_seen(axis_codes[X_AXIS])) || (code_seen(axis_codes[Y_AXIS])) || (code_seen(axis_codes[Z_AXIS])));

      #if Z_HOME_DIR > 0                      // If homing away from BED do Z first
      if((home_all_axis) || (code_seen(axis_codes[Z_AXIS]))) {
        HOMEAXIS(Z);
      }
      #endif

      #ifdef QUICK_HOME
      if((home_all_axis)||( code_seen(axis_codes[X_AXIS]) && code_seen(axis_codes[Y_AXIS])) )  //first diagonal move
      {
        current_position[X_AXIS] = 0;current_position[Y_AXIS] = 0;

       #ifndef DUAL_X_CARRIAGE
        int x_axis_home_dir = home_dir(X_AXIS);
       #else
        int x_axis_home_dir = x_home_dir(active_extruder);
        extruder_duplication_enabled = false;
       #endif

        plan_set_position(current_position[X_AXIS], current_position[Y_AXIS], current_position[Z_AXIS], current_position[E_AXIS]);
        destination[X_AXIS] = 1.5 * max_length(X_AXIS) * x_axis_home_dir;destination[Y_AXIS] = 1.5 * max_length(Y_AXIS) * home_dir(Y_AXIS);
        feedrate = homing_feedrate[X_AXIS];
        if(homing_feedrate[Y_AXIS]<feedrate)
          feedrate = homing_feedrate[Y_AXIS];
        if (max_length(X_AXIS) > max_length(Y_AXIS)) {
          feedrate *= sqrt(pow(max_length(Y_AXIS) / max_length(X_AXIS), 2) + 1);
        } else {
          feedrate *= sqrt(pow(max_length(X_AXIS) / max_length(Y_AXIS), 2) + 1);
        }
        plan_buffer_line(destination[X_AXIS], destination[Y_AXIS], destination[Z_AXIS], destination[E_AXIS], feedrate/60, active_extruder);
        st_synchronize();

        axis_is_at_home(X_AXIS);
        axis_is_at_home(Y_AXIS);
        plan_set_position(current_position[X_AXIS], current_position[Y_AXIS], current_position[Z_AXIS], current_position[E_AXIS]);
        destination[X_AXIS] = current_position[X_AXIS];
        destination[Y_AXIS] = current_position[Y_AXIS];
        plan_buffer_line(destination[X_AXIS], destination[Y_AXIS], destination[Z_AXIS], destination[E_AXIS], feedrate/60, active_extruder);
        feedrate = 0.0;
        st_synchronize();
        endstops_hit_on_purpose();

        current_position[X_AXIS] = destination[X_AXIS];
        current_position[Y_AXIS] = destination[Y_AXIS];
		#ifndef SCARA
        current_position[Z_AXIS] = destination[Z_AXIS];
		#endif
      }
      #endif

      if((home_all_axis) || (code_seen(axis_codes[X_AXIS])))
      {
      #ifdef DUAL_X_CARRIAGE
        int tmp_extruder = active_extruder;
        extruder_duplication_enabled = false;
        active_extruder = !active_extruder;
        HOMEAXIS(X);
        inactive_extruder_x_pos = current_position[X_AXIS];
        active_extruder = tmp_extruder;
        HOMEAXIS(X);
        // reset state used by the different modes
        memcpy(raised_parked_position, current_position, sizeof(raised_parked_position));
        delayed_move_time = 0;
        active_extruder_parked = true;
      #else
        HOMEAXIS(X);
      #endif
      }

      if((home_all_axis) || (code_seen(axis_codes[Y_AXIS]))) {
        HOMEAXIS(Y);
      }

      if(code_seen(axis_codes[X_AXIS]))
      {
        if(code_value_long() != 0) {
		#ifdef SCARA
		   current_position[X_AXIS]=code_value();
		#else
		   current_position[X_AXIS]=code_value()+add_homing[X_AXIS];
		#endif
        }
      }

      if(code_seen(axis_codes[Y_AXIS])) {
        if(code_value_long() != 0) {
         #ifdef SCARA
		   current_position[Y_AXIS]=code_value();
		#else
		   current_position[Y_AXIS]=code_value()+add_homing[Y_AXIS];
		#endif
        }
      }

      #if Z_HOME_DIR < 0                      // If homing towards BED do Z last
        #ifndef Z_SAFE_HOMING
          if((home_all_axis) || (code_seen(axis_codes[Z_AXIS]))) {
            #if defined (Z_RAISE_BEFORE_HOMING) && (Z_RAISE_BEFORE_HOMING > 0)
              destination[Z_AXIS] = Z_RAISE_BEFORE_HOMING * home_dir(Z_AXIS) * (-1);    // Set destination away from bed
              feedrate = max_feedrate[Z_AXIS];
              plan_buffer_line(destination[X_AXIS], destination[Y_AXIS], destination[Z_AXIS], destination[E_AXIS], feedrate, active_extruder);
              st_synchronize();
            #endif
            HOMEAXIS(Z);
          }
        #else                      // Z Safe mode activated.
          if(home_all_axis) {
            destination[X_AXIS] = round(Z_SAFE_HOMING_X_POINT - X_PROBE_OFFSET_FROM_EXTRUDER);
            destination[Y_AXIS] = round(Z_SAFE_HOMING_Y_POINT - Y_PROBE_OFFSET_FROM_EXTRUDER);
            destination[Z_AXIS] = Z_RAISE_BEFORE_HOMING * home_dir(Z_AXIS) * (-1);    // Set destination away from bed
            feedrate = XY_TRAVEL_SPEED/60;
            current_position[Z_AXIS] = 0;

            plan_set_position(current_position[X_AXIS], current_position[Y_AXIS], current_position[Z_AXIS], current_position[E_AXIS]);
            plan_buffer_line(destination[X_AXIS], destination[Y_AXIS], destination[Z_AXIS], destination[E_AXIS], feedrate, active_extruder);
            st_synchronize();
            current_position[X_AXIS] = destination[X_AXIS];
            current_position[Y_AXIS] = destination[Y_AXIS];

            HOMEAXIS(Z);
          }
                                                // Let's see if X and Y are homed and probe is inside bed area.
          if(code_seen(axis_codes[Z_AXIS])) {
            if ( (axis_known_position[X_AXIS]) && (axis_known_position[Y_AXIS]) \
              && (current_position[X_AXIS]+X_PROBE_OFFSET_FROM_EXTRUDER >= X_MIN_POS) \
              && (current_position[X_AXIS]+X_PROBE_OFFSET_FROM_EXTRUDER <= X_MAX_POS) \
              && (current_position[Y_AXIS]+Y_PROBE_OFFSET_FROM_EXTRUDER >= Y_MIN_POS) \
              && (current_position[Y_AXIS]+Y_PROBE_OFFSET_FROM_EXTRUDER <= Y_MAX_POS)) {

              current_position[Z_AXIS] = 0;
              plan_set_position(current_position[X_AXIS], current_position[Y_AXIS], current_position[Z_AXIS], current_position[E_AXIS]);
              destination[Z_AXIS] = Z_RAISE_BEFORE_HOMING * home_dir(Z_AXIS) * (-1);    // Set destination away from bed
              feedrate = max_feedrate[Z_AXIS];
              plan_buffer_line(destination[X_AXIS], destination[Y_AXIS], destination[Z_AXIS], destination[E_AXIS], feedrate, active_extruder);
              st_synchronize();

              HOMEAXIS(Z);
            } else if (!((axis_known_position[X_AXIS]) && (axis_known_position[Y_AXIS]))) {
                LCD_MESSAGEPGM(MSG_POSITION_UNKNOWN);
                SERIAL_ECHO_START;
                SERIAL_ECHOLNPGM(MSG_POSITION_UNKNOWN);
            } else {
                LCD_MESSAGEPGM(MSG_ZPROBE_OUT);
                SERIAL_ECHO_START;
                SERIAL_ECHOLNPGM(MSG_ZPROBE_OUT);
            }
          }
        #endif
      #endif



      if(code_seen(axis_codes[Z_AXIS])) {
        if(code_value_long() != 0) {
          current_position[Z_AXIS]=code_value()+add_homing[Z_AXIS];
        }
      }
      #ifdef ENABLE_AUTO_BED_LEVELING
        if((home_all_axis) || (code_seen(axis_codes[Z_AXIS]))) {
          current_position[Z_AXIS] += zprobe_zoffset;  //Add Z_Probe offset (the distance is negative)
        }
      #endif
      plan_set_position(current_position[X_AXIS], current_position[Y_AXIS], current_position[Z_AXIS], current_position[E_AXIS]);
#endif // else DELTA

#ifdef SCARA
	  calculate_delta(current_position);
      plan_set_position(delta[X_AXIS], delta[Y_AXIS], delta[Z_AXIS], current_position[E_AXIS]);
#endif // SCARA

      #ifdef ENDSTOPS_ONLY_FOR_HOMING
        enable_endstops(false);
      #endif

      feedrate = saved_feedrate;
      feedmultiply = saved_feedmultiply;
      previous_millis_cmd = millis();
      endstops_hit_on_purpose();
      break;

#ifdef ENABLE_AUTO_BED_LEVELING
    case 29: // G29 Detailed Z-Probe, probes the bed at 3 or more points.
    	     // Override probing area by providing [F]ront [B]ack [L]eft [R]ight Grid[P]oints values
        {
            #if Z_MIN_PIN == -1
            #error "You must have a Z_MIN endstop in order to enable Auto Bed Leveling feature!!! Z_MIN_PIN must point to a valid hardware pin."
            #endif

            // Prevent user from running a G29 without first homing in X and Y
            if (! (axis_known_position[X_AXIS] && axis_known_position[Y_AXIS]) )
            {
                LCD_MESSAGEPGM(MSG_POSITION_UNKNOWN);
                SERIAL_ECHO_START;
                SERIAL_ECHOLNPGM(MSG_POSITION_UNKNOWN);
                break; // abort G29, since we don't know where we are
            }

#ifdef Z_PROBE_SLED
            dock_sled(false);
#endif // Z_PROBE_SLED
            st_synchronize();
            // make sure the bed_level_rotation_matrix is identity or the planner will get it incorectly
            //vector_3 corrected_position = plan_get_position_mm();
            //corrected_position.debug("position before G29");
            plan_bed_level_matrix.set_to_identity();
            vector_3 uncorrected_position = plan_get_position();
            //uncorrected_position.debug("position durring G29");
            current_position[X_AXIS] = uncorrected_position.x;
            current_position[Y_AXIS] = uncorrected_position.y;
            current_position[Z_AXIS] = uncorrected_position.z;
            plan_set_position(current_position[X_AXIS], current_position[Y_AXIS], current_position[Z_AXIS], current_position[E_AXIS]);
            setup_for_endstop_move();

            feedrate = homing_feedrate[Z_AXIS];
#ifdef AUTO_BED_LEVELING_GRID
            // probe at the points of a lattice grid
            int left_probe_bed_position=LEFT_PROBE_BED_POSITION;
            int right_probe_bed_position=RIGHT_PROBE_BED_POSITION;
            int back_probe_bed_position=BACK_PROBE_BED_POSITION;
            int front_probe_bed_position=FRONT_PROBE_BED_POSITION;
            int auto_bed_leveling_grid_points=AUTO_BED_LEVELING_GRID_POINTS;
            if (code_seen('L')) left_probe_bed_position=(int)code_value();
            if (code_seen('R')) right_probe_bed_position=(int)code_value();
            if (code_seen('B')) back_probe_bed_position=(int)code_value();
            if (code_seen('F')) front_probe_bed_position=(int)code_value();
            if (code_seen('P')) auto_bed_leveling_grid_points=(int)code_value();

            int xGridSpacing = (right_probe_bed_position - left_probe_bed_position) / (auto_bed_leveling_grid_points-1);
            int yGridSpacing = (back_probe_bed_position - front_probe_bed_position) / (auto_bed_leveling_grid_points-1);


            // solve the plane equation ax + by + d = z
            // A is the matrix with rows [x y 1] for all the probed points
            // B is the vector of the Z positions
            // the normal vector to the plane is formed by the coefficients of the plane equation in the standard form, which is Vx*x+Vy*y+Vz*z+d = 0
            // so Vx = -a Vy = -b Vz = 1 (we want the vector facing towards positive Z

            // "A" matrix of the linear system of equations
            double eqnAMatrix[auto_bed_leveling_grid_points*auto_bed_leveling_grid_points*3];

            // "B" vector of Z points
            double eqnBVector[auto_bed_leveling_grid_points*auto_bed_leveling_grid_points];



            int probePointCounter = 0;
            bool zig = true;

            for (int yProbe=front_probe_bed_position; yProbe <= back_probe_bed_position; yProbe += yGridSpacing)

            {
              int xProbe, xInc;
              if (zig)
              {
                xProbe = left_probe_bed_position;
                //xEnd = right_probe_bed_position;
                xInc = xGridSpacing;
                zig = false;
              } else // zag
              {
                xProbe = right_probe_bed_position;
                //xEnd = left_probe_bed_position;
                xInc = -xGridSpacing;
                zig = true;
              }

              for (int xCount=0; xCount < auto_bed_leveling_grid_points; xCount++)
              {
                float z_before;
                if (probePointCounter == 0)
                {
                  // raise before probing
                  z_before = Z_RAISE_BEFORE_PROBING;
                } else
                {
                  // raise extruder
                  z_before = current_position[Z_AXIS] + Z_RAISE_BETWEEN_PROBINGS;
                }

                float measured_z;
                //Enhanced G29 - Do not retract servo between probes
                if (code_seen('E') || code_seen('e') )
                   {
                   if ((yProbe==FRONT_PROBE_BED_POSITION) && (xCount==0))
                       {
                        measured_z = probe_pt(xProbe, yProbe, z_before,1);
                       } else if ((yProbe==FRONT_PROBE_BED_POSITION + (yGridSpacing * (AUTO_BED_LEVELING_GRID_POINTS-1))) && (xCount == AUTO_BED_LEVELING_GRID_POINTS-1))
                         {
                         measured_z = probe_pt(xProbe, yProbe, z_before,3);
                         } else {
                           measured_z = probe_pt(xProbe, yProbe, z_before,2);
                         }
                    } else {
                    measured_z = probe_pt(xProbe, yProbe, z_before);
                    }

                eqnBVector[probePointCounter] = measured_z;

                eqnAMatrix[probePointCounter + 0*auto_bed_leveling_grid_points*auto_bed_leveling_grid_points] = xProbe;
                eqnAMatrix[probePointCounter + 1*auto_bed_leveling_grid_points*auto_bed_leveling_grid_points] = yProbe;
                eqnAMatrix[probePointCounter + 2*auto_bed_leveling_grid_points*auto_bed_leveling_grid_points] = 1;
                probePointCounter++;
                xProbe += xInc;
              }
            }
            clean_up_after_endstop_move();

            // solve lsq problem
            double *plane_equation_coefficients = qr_solve(auto_bed_leveling_grid_points*auto_bed_leveling_grid_points, 3, eqnAMatrix, eqnBVector);

            SERIAL_PROTOCOLPGM("Eqn coefficients: a: ");
            SERIAL_PROTOCOL(plane_equation_coefficients[0]);
            SERIAL_PROTOCOLPGM(" b: ");
            SERIAL_PROTOCOL(plane_equation_coefficients[1]);
            SERIAL_PROTOCOLPGM(" d: ");
            SERIAL_PROTOCOLLN(plane_equation_coefficients[2]);


            set_bed_level_equation_lsq(plane_equation_coefficients);

            free(plane_equation_coefficients);

#else // AUTO_BED_LEVELING_GRID not defined

            // Probe at 3 arbitrary points
            // Enhanced G29
            
            float z_at_pt_1, z_at_pt_2, z_at_pt_3;
            
            if (code_seen('E') || code_seen('e')) {
              // probe 1               
              z_at_pt_1 = probe_pt(ABL_PROBE_PT_1_X, ABL_PROBE_PT_1_Y, Z_RAISE_BEFORE_PROBING,1);
              // probe 2
              z_at_pt_2 = probe_pt(ABL_PROBE_PT_2_X, ABL_PROBE_PT_2_Y, current_position[Z_AXIS] + Z_RAISE_BETWEEN_PROBINGS,2);
              // probe 3
              z_at_pt_3 = probe_pt(ABL_PROBE_PT_3_X, ABL_PROBE_PT_3_Y, current_position[Z_AXIS] + Z_RAISE_BETWEEN_PROBINGS,3); 
            }
            else {
              // probe 1
              z_at_pt_1 = probe_pt(ABL_PROBE_PT_1_X, ABL_PROBE_PT_1_Y, Z_RAISE_BEFORE_PROBING);
              // probe 2
              z_at_pt_2 = probe_pt(ABL_PROBE_PT_2_X, ABL_PROBE_PT_2_Y, current_position[Z_AXIS] + Z_RAISE_BETWEEN_PROBINGS);
              // probe 3
              z_at_pt_3 = probe_pt(ABL_PROBE_PT_3_X, ABL_PROBE_PT_3_Y, current_position[Z_AXIS] + Z_RAISE_BETWEEN_PROBINGS);
            }
            clean_up_after_endstop_move();
            set_bed_level_equation_3pts(z_at_pt_1, z_at_pt_2, z_at_pt_3);


#endif // AUTO_BED_LEVELING_GRID
            st_synchronize();

            // The following code correct the Z height difference from z-probe position and hotend tip position.
            // The Z height on homing is measured by Z-Probe, but the probe is quite far from the hotend.
            // When the bed is uneven, this height must be corrected.
            real_z = float(st_get_position(Z_AXIS))/axis_steps_per_unit[Z_AXIS];  //get the real Z (since the auto bed leveling is already correcting the plane)
            x_tmp = current_position[X_AXIS] + X_PROBE_OFFSET_FROM_EXTRUDER;
            y_tmp = current_position[Y_AXIS] + Y_PROBE_OFFSET_FROM_EXTRUDER;
            z_tmp = current_position[Z_AXIS];

            apply_rotation_xyz(plan_bed_level_matrix, x_tmp, y_tmp, z_tmp);         //Apply the correction sending the probe offset
            current_position[Z_AXIS] = z_tmp - real_z + current_position[Z_AXIS];   //The difference is added to current position and sent to planner.
            plan_set_position(current_position[X_AXIS], current_position[Y_AXIS], current_position[Z_AXIS], current_position[E_AXIS]);
#ifdef Z_PROBE_SLED
            dock_sled(true, -SLED_DOCKING_OFFSET); // correct for over travel.
#endif // Z_PROBE_SLED
        }
        break;
#ifndef Z_PROBE_SLED
    case 30: // G30 Single Z Probe
        {
            engage_z_probe(); // Engage Z Servo endstop if available
            st_synchronize();
            // TODO: make sure the bed_level_rotation_matrix is identity or the planner will get set incorectly
            setup_for_endstop_move();

            feedrate = homing_feedrate[Z_AXIS];

            run_z_probe();
            SERIAL_PROTOCOLPGM(MSG_BED);
            SERIAL_PROTOCOLPGM(" X: ");
            SERIAL_PROTOCOL(current_position[X_AXIS]);
            SERIAL_PROTOCOLPGM(" Y: ");
            SERIAL_PROTOCOL(current_position[Y_AXIS]);
            SERIAL_PROTOCOLPGM(" Z: ");
            SERIAL_PROTOCOL(current_position[Z_AXIS]);
            SERIAL_PROTOCOLPGM("\n");

            clean_up_after_endstop_move();
            retract_z_probe(); // Retract Z Servo endstop if available
        }
        break;
#else
    case 31: // dock the sled
        dock_sled(true);
        break;
    case 32: // undock the sled
        dock_sled(false);
        break;
#endif // Z_PROBE_SLED
#endif // ENABLE_AUTO_BED_LEVELING
    case 90: // G90
      relative_mode = false;
      break;
    case 91: // G91
      relative_mode = true;
      break;
    case 92: // G92
      if(!code_seen(axis_codes[E_AXIS]))
        st_synchronize();
      for(int8_t i=0; i < NUM_AXIS; i++) {
        if(code_seen(axis_codes[i])) {
           if(i == E_AXIS) {
             current_position[i] = code_value();
             plan_set_e_position(current_position[E_AXIS]);
           }
           else {
#ifdef SCARA
		if (i == X_AXIS || i == Y_AXIS) {
                	current_position[i] = code_value();  
		}
		else {
                current_position[i] = code_value()+add_homing[i];  
            	}  
#else
		current_position[i] = code_value()+add_homing[i];
#endif
            plan_set_position(current_position[X_AXIS], current_position[Y_AXIS], current_position[Z_AXIS], current_position[E_AXIS]);
           }
        }
      }
      break;
    }
  }

  else if(code_seen('M'))
  {
    switch( (int)code_value() )
    {
#ifdef ULTIPANEL
    case 0: // M0 - Unconditional stop - Wait for user button press on LCD
    case 1: // M1 - Conditional stop - Wait for user button press on LCD
    {
      char *src = strchr_pointer + 2;

      codenum = 0;

      bool hasP = false, hasS = false;
      if (code_seen('P')) {
        codenum = code_value(); // milliseconds to wait
        hasP = codenum > 0;
      }
      if (code_seen('S')) {
        codenum = code_value() * 1000; // seconds to wait
        hasS = codenum > 0;
      }
      starpos = strchr(src, '*');
      if (starpos != NULL) *(starpos) = '\0';
      while (*src == ' ') ++src;
      if (!hasP && !hasS && *src != '\0') {
        lcd_setstatus(src);
      } else {
        LCD_MESSAGEPGM(MSG_USERWAIT);
      }

      lcd_ignore_click();
      st_synchronize();
      previous_millis_cmd = millis();
      if (codenum > 0){
        codenum += millis();  // keep track of when we started waiting
        while(millis() < codenum && !lcd_clicked()){
          manage_heater();
          manage_inactivity();
          lcd_update();
        }
        lcd_ignore_click(false);
      }else{
          if (!lcd_detected())
            break;
        while(!lcd_clicked()){
          manage_heater();
          manage_inactivity();
          lcd_update();
        }
      }
      if (IS_SD_PRINTING)
        LCD_MESSAGEPGM(MSG_RESUMING);
      else
        LCD_MESSAGEPGM(WELCOME_MSG);
    }
    break;
#endif
    case 17:
        LCD_MESSAGEPGM(MSG_NO_MOVE);
        enable_x();
        enable_y();
        enable_z();
        enable_e0();
        enable_e1();
        enable_e2();
      break;

#ifdef SDSUPPORT
    case 20: // M20 - list SD card
      SERIAL_PROTOCOLLNPGM(MSG_BEGIN_FILE_LIST);
      card.ls();
      SERIAL_PROTOCOLLNPGM(MSG_END_FILE_LIST);
      break;
    case 21: // M21 - init SD card

      card.initsd();

      break;
    case 22: //M22 - release SD card
      card.release();

      break;
    case 23: //M23 - Select file
      starpos = (strchr(strchr_pointer + 4,'*'));
      if(starpos!=NULL)
        *(starpos)='\0';
      card.openFile(strchr_pointer + 4,true);
      break;
    case 24: //M24 - Start SD print
      card.startFileprint();
      starttime=millis();
      break;
    case 25: //M25 - Pause SD print
      card.pauseSDPrint();
      break;
    case 26: //M26 - Set SD index
      if(card.cardOK && code_seen('S')) {
        card.setIndex(code_value_long());
      }
      break;
    case 27: //M27 - Get SD status
      card.getStatus();
      break;
    case 28: //M28 - Start SD write
      starpos = (strchr(strchr_pointer + 4,'*'));
      if(starpos != NULL){
        char* npos = strchr(cmdbuffer[bufindr], 'N');
        strchr_pointer = strchr(npos,' ') + 1;
        *(starpos) = '\0';
      }
      card.openFile(strchr_pointer+4,false);
      break;
    case 29: //M29 - Stop SD write
      //processed in write to file routine above
      //card,saving = false;
      break;
    case 30: //M30 <filename> Delete File
      if (card.cardOK){
        card.closefile();
        starpos = (strchr(strchr_pointer + 4,'*'));
        if(starpos != NULL){
          char* npos = strchr(cmdbuffer[bufindr], 'N');
          strchr_pointer = strchr(npos,' ') + 1;
          *(starpos) = '\0';
        }
        card.removeFile(strchr_pointer + 4);
      }
      break;
    case 32: //M32 - Select file and start SD print
    {
      if(card.sdprinting) {
        st_synchronize();

      }
      starpos = (strchr(strchr_pointer + 4,'*'));

      char* namestartpos = (strchr(strchr_pointer + 4,'!'));   //find ! to indicate filename string start.
      if(namestartpos==NULL)
      {
        namestartpos=strchr_pointer + 4; //default name position, 4 letters after the M
      }
      else
        namestartpos++; //to skip the '!'

      if(starpos!=NULL)
        *(starpos)='\0';

      bool call_procedure=(code_seen('P'));

      if(strchr_pointer>namestartpos)
        call_procedure=false;  //false alert, 'P' found within filename

      if( card.cardOK )
      {
        card.openFile(namestartpos,true,!call_procedure);
        if(code_seen('S'))
          if(strchr_pointer<namestartpos) //only if "S" is occuring _before_ the filename
            card.setIndex(code_value_long());
        card.startFileprint();
        if(!call_procedure)
          starttime=millis(); //procedure calls count as normal print time.
      }
    } break;
    case 928: //M928 - Start SD write
      starpos = (strchr(strchr_pointer + 5,'*'));
      if(starpos != NULL){
        char* npos = strchr(cmdbuffer[bufindr], 'N');
        strchr_pointer = strchr(npos,' ') + 1;
        *(starpos) = '\0';
      }
      card.openLogFile(strchr_pointer+5);
      break;

#endif //SDSUPPORT

    case 31: //M31 take time since the start of the SD print or an M109 command
      {
      stoptime=millis();
      char time[30];
      unsigned long t=(stoptime-starttime)/1000;
      int sec,min;
      min=t/60;
      sec=t%60;
      sprintf_P(time, PSTR("%i min, %i sec"), min, sec);
      SERIAL_ECHO_START;
      SERIAL_ECHOLN(time);
      lcd_setstatus(time);
      autotempShutdown();
      }
      break;
    case 42: //M42 -Change pin status via gcode
      if (code_seen('S'))
      {
        int pin_status = code_value();
        int pin_number = LED_PIN;
        if (code_seen('P') && pin_status >= 0 && pin_status <= 255)
          pin_number = code_value();
        for(int8_t i = 0; i < (int8_t)(sizeof(sensitive_pins)/sizeof(int)); i++)
        {
          if (sensitive_pins[i] == pin_number)
          {
            pin_number = -1;
            break;
          }
        }
      #if defined(FAN_PIN) && FAN_PIN > -1
        if (pin_number == FAN_PIN)
          fanSpeed = pin_status;
      #endif
        if (pin_number > -1)
        {
          pinMode(pin_number, OUTPUT);
          digitalWrite(pin_number, pin_status);
          analogWrite(pin_number, pin_status);
        }
      }
     break;

// M48 Z-Probe repeatability measurement function.
//
// Usage:   M48 <n #_samples> <X X_position_for_samples> <Y Y_position_for_samples> <V Verbose_Level> <Engage_probe_for_each_reading> <L legs_of_movement_prior_to_doing_probe>
//	
// This function assumes the bed has been homed.  Specificaly, that a G28 command
// as been issued prior to invoking the M48 Z-Probe repeatability measurement function.
// Any information generated by a prior G29 Bed leveling command will be lost and need to be
// regenerated.
//
// The number of samples will default to 10 if not specified.  You can use upper or lower case
// letters for any of the options EXCEPT n.  n must be in lower case because Marlin uses a capital
// N for its communication protocol and will get horribly confused if you send it a capital N.
//

#ifdef ENABLE_AUTO_BED_LEVELING
#ifdef Z_PROBE_REPEATABILITY_TEST 

    case 48: // M48 Z-Probe repeatability
        {
            #if Z_MIN_PIN == -1
            #error "You must have a Z_MIN endstop in order to enable calculation of Z-Probe repeatability."
            #endif

	double sum=0.0; 
	double mean=0.0; 
	double sigma=0.0;
	double sample_set[50];
	int verbose_level=1, n=0, j, n_samples = 10, n_legs=0, engage_probe_for_each_reading=0 ;
	double X_current, Y_current, Z_current;
	double X_probe_location, Y_probe_location, Z_start_location, ext_position;
	
	if (code_seen('V') || code_seen('v')) {
        	verbose_level = code_value();
		if (verbose_level<0 || verbose_level>4 ) {
			SERIAL_PROTOCOLPGM("?Verbose Level not plausable.\n");
			goto Sigma_Exit;
		}
	}

	if (verbose_level > 0)   {
		SERIAL_PROTOCOLPGM("M48 Z-Probe Repeatability test.   Version 2.00\n");
		SERIAL_PROTOCOLPGM("Full support at: http://3dprintboard.com/forum.php\n");
	}

	if (code_seen('n')) {
        	n_samples = code_value();
		if (n_samples<4 || n_samples>50 ) {
			SERIAL_PROTOCOLPGM("?Specified sample size not plausable.\n");
			goto Sigma_Exit;
		}
	}

	X_current = X_probe_location = st_get_position_mm(X_AXIS);
	Y_current = Y_probe_location = st_get_position_mm(Y_AXIS);
	Z_current = st_get_position_mm(Z_AXIS);
	Z_start_location = st_get_position_mm(Z_AXIS) + Z_RAISE_BEFORE_PROBING;
	ext_position	 = st_get_position_mm(E_AXIS);

	if (code_seen('E') || code_seen('e') ) 
		engage_probe_for_each_reading++;

	if (code_seen('X') || code_seen('x') ) {
        	X_probe_location = code_value() -  X_PROBE_OFFSET_FROM_EXTRUDER;
		if (X_probe_location<X_MIN_POS || X_probe_location>X_MAX_POS ) {
			SERIAL_PROTOCOLPGM("?Specified X position out of range.\n");
			goto Sigma_Exit;
		}
	}

	if (code_seen('Y') || code_seen('y') ) {
        	Y_probe_location = code_value() -  Y_PROBE_OFFSET_FROM_EXTRUDER;
		if (Y_probe_location<Y_MIN_POS || Y_probe_location>Y_MAX_POS ) {
			SERIAL_PROTOCOLPGM("?Specified Y position out of range.\n");
			goto Sigma_Exit;
		}
	}

	if (code_seen('L') || code_seen('l') ) {
        	n_legs = code_value();
		if ( n_legs==1 ) 
			n_legs = 2;
		if ( n_legs<0 || n_legs>15 ) {
			SERIAL_PROTOCOLPGM("?Specified number of legs in movement not plausable.\n");
			goto Sigma_Exit;
		}
	}

//
// Do all the preliminary setup work.   First raise the probe.
//

        st_synchronize();
        plan_bed_level_matrix.set_to_identity();
	plan_buffer_line( X_current, Y_current, Z_start_location,
			ext_position,
    			homing_feedrate[Z_AXIS]/60,
			active_extruder);
        st_synchronize();

//
// Now get everything to the specified probe point So we can safely do a probe to
// get us close to the bed.  If the Z-Axis is far from the bed, we don't want to 
// use that as a starting point for each probe.
//
	if (verbose_level > 2) 
		SERIAL_PROTOCOL("Positioning probe for the test.\n");

	plan_buffer_line( X_probe_location, Y_probe_location, Z_start_location,
			ext_position,
    			homing_feedrate[X_AXIS]/60,
			active_extruder);
        st_synchronize();

	current_position[X_AXIS] = X_current = st_get_position_mm(X_AXIS);
	current_position[Y_AXIS] = Y_current = st_get_position_mm(Y_AXIS);
	current_position[Z_AXIS] = Z_current = st_get_position_mm(Z_AXIS);
	current_position[E_AXIS] = ext_position = st_get_position_mm(E_AXIS);

// 
// OK, do the inital probe to get us close to the bed.
// Then retrace the right amount and use that in subsequent probes
//

        engage_z_probe();	

	setup_for_endstop_move();
	run_z_probe();

	current_position[Z_AXIS] = Z_current = st_get_position_mm(Z_AXIS);
	Z_start_location = st_get_position_mm(Z_AXIS) + Z_RAISE_BEFORE_PROBING;

	plan_buffer_line( X_probe_location, Y_probe_location, Z_start_location,
			ext_position,
    			homing_feedrate[X_AXIS]/60,
			active_extruder);
        st_synchronize();
	current_position[Z_AXIS] = Z_current = st_get_position_mm(Z_AXIS);

	if (engage_probe_for_each_reading)
        	retract_z_probe();

        for( n=0; n<n_samples; n++) {

		do_blocking_move_to( X_probe_location, Y_probe_location, Z_start_location); // Make sure we are at the probe location

		if ( n_legs)  {
		double radius=0.0, theta=0.0, x_sweep, y_sweep;
		int rotational_direction, l;

			rotational_direction = (unsigned long) millis() & 0x0001;			// clockwise or counter clockwise
			radius = (unsigned long) millis() % (long) (X_MAX_LENGTH/4); 			// limit how far out to go 
			theta = (float) ((unsigned long) millis() % (long) 360) / (360./(2*3.1415926));	// turn into radians

//SERIAL_ECHOPAIR("starting radius: ",radius);
//SERIAL_ECHOPAIR("   theta: ",theta);
//SERIAL_ECHOPAIR("   direction: ",rotational_direction);
//SERIAL_PROTOCOLLNPGM("");

			for( l=0; l<n_legs-1; l++) {
				if (rotational_direction==1)
					theta += (float) ((unsigned long) millis() % (long) 20) / (360.0/(2*3.1415926)); // turn into radians
				else
					theta -= (float) ((unsigned long) millis() % (long) 20) / (360.0/(2*3.1415926)); // turn into radians

				radius += (float) ( ((long) ((unsigned long) millis() % (long) 10)) - 5);
				if ( radius<0.0 )
					radius = -radius;

				X_current = X_probe_location + cos(theta) * radius;
				Y_current = Y_probe_location + sin(theta) * radius;

				if ( X_current<X_MIN_POS)		// Make sure our X & Y are sane
					 X_current = X_MIN_POS;
				if ( X_current>X_MAX_POS)
					 X_current = X_MAX_POS;

				if ( Y_current<Y_MIN_POS)		// Make sure our X & Y are sane
					 Y_current = Y_MIN_POS;
				if ( Y_current>Y_MAX_POS)
					 Y_current = Y_MAX_POS;

				if (verbose_level>3 ) {
					SERIAL_ECHOPAIR("x: ", X_current);
					SERIAL_ECHOPAIR("y: ", Y_current);
					SERIAL_PROTOCOLLNPGM("");
				}

				do_blocking_move_to( X_current, Y_current, Z_current );
			}
			do_blocking_move_to( X_probe_location, Y_probe_location, Z_start_location); // Go back to the probe location
		}

		if (engage_probe_for_each_reading)  {
        		engage_z_probe();	
          		delay(1000);
		}

		setup_for_endstop_move();
                run_z_probe();

		sample_set[n] = current_position[Z_AXIS];

//
// Get the current mean for the data points we have so far
//
		sum=0.0; 
		for( j=0; j<=n; j++) {
			sum = sum + sample_set[j];
		}
		mean = sum / (double (n+1));
//
// Now, use that mean to calculate the standard deviation for the
// data points we have so far
//

		sum=0.0; 
		for( j=0; j<=n; j++) {
			sum = sum + (sample_set[j]-mean) * (sample_set[j]-mean);
		}
		sigma = sqrt( sum / (double (n+1)) );

		if (verbose_level > 1) {
			SERIAL_PROTOCOL(n+1);
			SERIAL_PROTOCOL(" of ");
			SERIAL_PROTOCOL(n_samples);
			SERIAL_PROTOCOLPGM("   z: ");
			SERIAL_PROTOCOL_F(current_position[Z_AXIS], 6);
		}

		if (verbose_level > 2) {
			SERIAL_PROTOCOL(" mean: ");
			SERIAL_PROTOCOL_F(mean,6);

			SERIAL_PROTOCOL("   sigma: ");
			SERIAL_PROTOCOL_F(sigma,6);
		}

		if (verbose_level > 0) 
			SERIAL_PROTOCOLPGM("\n");

		plan_buffer_line( X_probe_location, Y_probe_location, Z_start_location, 
				  current_position[E_AXIS], homing_feedrate[Z_AXIS]/60, active_extruder);
        	st_synchronize();

		if (engage_probe_for_each_reading)  {
        		retract_z_probe();	
          		delay(1000);
		}
	}

        retract_z_probe();
	delay(1000);

        clean_up_after_endstop_move();

//      enable_endstops(true);

	if (verbose_level > 0) {
		SERIAL_PROTOCOLPGM("Mean: ");
		SERIAL_PROTOCOL_F(mean, 6);
		SERIAL_PROTOCOLPGM("\n");
	}

SERIAL_PROTOCOLPGM("Standard Deviation: ");
SERIAL_PROTOCOL_F(sigma, 6);
SERIAL_PROTOCOLPGM("\n\n");

Sigma_Exit:
        break;
	}
#endif		// Z_PROBE_REPEATABILITY_TEST 
#endif		// ENABLE_AUTO_BED_LEVELING

    case 104: // M104
      if(setTargetedHotend(104)){
        break;
      }
      if (code_seen('S')) setTargetHotend(code_value(), tmp_extruder);
#ifdef DUAL_X_CARRIAGE
      if (dual_x_carriage_mode == DXC_DUPLICATION_MODE && tmp_extruder == 0)
        setTargetHotend1(code_value() == 0.0 ? 0.0 : code_value() + duplicate_extruder_temp_offset);
#endif
      setWatch();
      break;
    case 112: //  M112 -Emergency Stop
      kill();
      break;
    case 140: // M140 set bed temp
      if (code_seen('S')) setTargetBed(code_value());
      break;
    case 105 : // M105
      if(setTargetedHotend(105)){
        break;
        }
      #if defined(TEMP_0_PIN) && TEMP_0_PIN > -1
        SERIAL_PROTOCOLPGM("ok T:");
        SERIAL_PROTOCOL_F(degHotend(tmp_extruder),1);
        SERIAL_PROTOCOLPGM(" /");
        SERIAL_PROTOCOL_F(degTargetHotend(tmp_extruder),1);
        #if defined(TEMP_BED_PIN) && TEMP_BED_PIN > -1
          SERIAL_PROTOCOLPGM(" B:");
          SERIAL_PROTOCOL_F(degBed(),1);
          SERIAL_PROTOCOLPGM(" /");
          SERIAL_PROTOCOL_F(degTargetBed(),1);
        #endif //TEMP_BED_PIN
        for (int8_t cur_extruder = 0; cur_extruder < EXTRUDERS; ++cur_extruder) {
          SERIAL_PROTOCOLPGM(" T");
          SERIAL_PROTOCOL(cur_extruder);
          SERIAL_PROTOCOLPGM(":");
          SERIAL_PROTOCOL_F(degHotend(cur_extruder),1);
          SERIAL_PROTOCOLPGM(" /");
          SERIAL_PROTOCOL_F(degTargetHotend(cur_extruder),1);
        }
      #else
        SERIAL_ERROR_START;
        SERIAL_ERRORLNPGM(MSG_ERR_NO_THERMISTORS);
      #endif

        SERIAL_PROTOCOLPGM(" @:");
      #ifdef EXTRUDER_WATTS
        SERIAL_PROTOCOL((EXTRUDER_WATTS * getHeaterPower(tmp_extruder))/127);
        SERIAL_PROTOCOLPGM("W");
      #else
        SERIAL_PROTOCOL(getHeaterPower(tmp_extruder));
      #endif

        SERIAL_PROTOCOLPGM(" B@:");
      #ifdef BED_WATTS
        SERIAL_PROTOCOL((BED_WATTS * getHeaterPower(-1))/127);
        SERIAL_PROTOCOLPGM("W");
      #else
        SERIAL_PROTOCOL(getHeaterPower(-1));
      #endif

        #ifdef SHOW_TEMP_ADC_VALUES
          #if defined(TEMP_BED_PIN) && TEMP_BED_PIN > -1
            SERIAL_PROTOCOLPGM("    ADC B:");
            SERIAL_PROTOCOL_F(degBed(),1);
            SERIAL_PROTOCOLPGM("C->");
            SERIAL_PROTOCOL_F(rawBedTemp()/OVERSAMPLENR,0);
          #endif
          for (int8_t cur_extruder = 0; cur_extruder < EXTRUDERS; ++cur_extruder) {
            SERIAL_PROTOCOLPGM("  T");
            SERIAL_PROTOCOL(cur_extruder);
            SERIAL_PROTOCOLPGM(":");
            SERIAL_PROTOCOL_F(degHotend(cur_extruder),1);
            SERIAL_PROTOCOLPGM("C->");
            SERIAL_PROTOCOL_F(rawHotendTemp(cur_extruder)/OVERSAMPLENR,0);
          }
        #endif

        SERIAL_PROTOCOLLN("");
      return;
      break;
    case 109:
    {// M109 - Wait for extruder heater to reach target.
      if(setTargetedHotend(109)){
        break;
      }
      LCD_MESSAGEPGM(MSG_HEATING);
      #ifdef AUTOTEMP
        autotemp_enabled=false;
      #endif
      if (code_seen('S')) {
        setTargetHotend(code_value(), tmp_extruder);
#ifdef DUAL_X_CARRIAGE
        if (dual_x_carriage_mode == DXC_DUPLICATION_MODE && tmp_extruder == 0)
          setTargetHotend1(code_value() == 0.0 ? 0.0 : code_value() + duplicate_extruder_temp_offset);
#endif
        CooldownNoWait = true;
      } else if (code_seen('R')) {
        setTargetHotend(code_value(), tmp_extruder);
#ifdef DUAL_X_CARRIAGE
        if (dual_x_carriage_mode == DXC_DUPLICATION_MODE && tmp_extruder == 0)
          setTargetHotend1(code_value() == 0.0 ? 0.0 : code_value() + duplicate_extruder_temp_offset);
#endif
        CooldownNoWait = false;
      }
      #ifdef AUTOTEMP
        if (code_seen('S')) autotemp_min=code_value();
        if (code_seen('B')) autotemp_max=code_value();
        if (code_seen('F'))
        {
          autotemp_factor=code_value();
          autotemp_enabled=true;
        }
      #endif

      setWatch();
      codenum = millis();

      /* See if we are heating up or cooling down */
      target_direction = isHeatingHotend(tmp_extruder); // true if heating, false if cooling

      cancel_heatup = false;

      #ifdef TEMP_RESIDENCY_TIME
        long residencyStart;
        residencyStart = -1;
        /* continue to loop until we have reached the target temp
          _and_ until TEMP_RESIDENCY_TIME hasn't passed since we reached it */
        while((!cancel_heatup)&&((residencyStart == -1) ||
              (residencyStart >= 0 && (((unsigned int) (millis() - residencyStart)) < (TEMP_RESIDENCY_TIME * 1000UL)))) ) {
      #else
        while ( target_direction ? (isHeatingHotend(tmp_extruder)) : (isCoolingHotend(tmp_extruder)&&(CooldownNoWait==false)) ) {
      #endif //TEMP_RESIDENCY_TIME
          if( (millis() - codenum) > 1000UL )
          { //Print Temp Reading and remaining time every 1 second while heating up/cooling down
            SERIAL_PROTOCOLPGM("T:");
            SERIAL_PROTOCOL_F(degHotend(tmp_extruder),1);
            SERIAL_PROTOCOLPGM(" E:");
            SERIAL_PROTOCOL((int)tmp_extruder);
            #ifdef TEMP_RESIDENCY_TIME
              SERIAL_PROTOCOLPGM(" W:");
              if(residencyStart > -1)
              {
                 codenum = ((TEMP_RESIDENCY_TIME * 1000UL) - (millis() - residencyStart)) / 1000UL;
                 SERIAL_PROTOCOLLN( codenum );
              }
              else
              {
                 SERIAL_PROTOCOLLN( "?" );
              }
            #else
              SERIAL_PROTOCOLLN("");
            #endif
            codenum = millis();
          }
          manage_heater();
          manage_inactivity();
          lcd_update();
        #ifdef TEMP_RESIDENCY_TIME
            /* start/restart the TEMP_RESIDENCY_TIME timer whenever we reach target temp for the first time
              or when current temp falls outside the hysteresis after target temp was reached */
          if ((residencyStart == -1 &&  target_direction && (degHotend(tmp_extruder) >= (degTargetHotend(tmp_extruder)-TEMP_WINDOW))) ||
              (residencyStart == -1 && !target_direction && (degHotend(tmp_extruder) <= (degTargetHotend(tmp_extruder)+TEMP_WINDOW))) ||
              (residencyStart > -1 && labs(degHotend(tmp_extruder) - degTargetHotend(tmp_extruder)) > TEMP_HYSTERESIS) )
          {
            residencyStart = millis();
          }
        #endif //TEMP_RESIDENCY_TIME
        }
        LCD_MESSAGEPGM(MSG_HEATING_COMPLETE);
        starttime=millis();
        previous_millis_cmd = millis();
      }
      break;
    case 190: // M190 - Wait for bed heater to reach target.
    #if defined(TEMP_BED_PIN) && TEMP_BED_PIN > -1
        LCD_MESSAGEPGM(MSG_BED_HEATING);
        if (code_seen('S')) {
          setTargetBed(code_value());
          CooldownNoWait = true;
        } else if (code_seen('R')) {
          setTargetBed(code_value());
          CooldownNoWait = false;
        }
        codenum = millis();
        
        cancel_heatup = false;
        target_direction = isHeatingBed(); // true if heating, false if cooling

        while ( (target_direction)&&(!cancel_heatup) ? (isHeatingBed()) : (isCoolingBed()&&(CooldownNoWait==false)) )
        {
          if(( millis() - codenum) > 1000 ) //Print Temp Reading every 1 second while heating up.
          {
            float tt=degHotend(active_extruder);
            SERIAL_PROTOCOLPGM("T:");
            SERIAL_PROTOCOL(tt);
            SERIAL_PROTOCOLPGM(" E:");
            SERIAL_PROTOCOL((int)active_extruder);
            SERIAL_PROTOCOLPGM(" B:");
            SERIAL_PROTOCOL_F(degBed(),1);
            SERIAL_PROTOCOLLN("");
            codenum = millis();
          }
          manage_heater();
          manage_inactivity();
          lcd_update();
        }
        LCD_MESSAGEPGM(MSG_BED_DONE);
        previous_millis_cmd = millis();
    #endif
        break;

    #if defined(FAN_PIN) && FAN_PIN > -1
      case 106: //M106 Fan On
        if (code_seen('S')){
           fanSpeed=constrain(code_value(),0,255);
        }
        else {
          fanSpeed=255;
        }
        break;
      case 107: //M107 Fan Off
        fanSpeed = 0;
        break;
    #endif //FAN_PIN
    #ifdef BARICUDA
      // PWM for HEATER_1_PIN
      #if defined(HEATER_1_PIN) && HEATER_1_PIN > -1
        case 126: //M126 valve open
          if (code_seen('S')){
             ValvePressure=constrain(code_value(),0,255);
          }
          else {
            ValvePressure=255;
          }
          break;
        case 127: //M127 valve closed
          ValvePressure = 0;
          break;
      #endif //HEATER_1_PIN

      // PWM for HEATER_2_PIN
      #if defined(HEATER_2_PIN) && HEATER_2_PIN > -1
        case 128: //M128 valve open
          if (code_seen('S')){
             EtoPPressure=constrain(code_value(),0,255);
          }
          else {
            EtoPPressure=255;
          }
          break;
        case 129: //M129 valve closed
          EtoPPressure = 0;
          break;
      #endif //HEATER_2_PIN
    #endif

    #if defined(PS_ON_PIN) && PS_ON_PIN > -1
      case 80: // M80 - Turn on Power Supply
        OUT_WRITE(PS_ON_PIN, PS_ON_AWAKE); // GND

        // If you have a switch on suicide pin, this is useful
        // if you want to start another print with suicide feature after
        // a print without suicide...
        #if defined SUICIDE_PIN && SUICIDE_PIN > -1
            OUT_WRITE(SUICIDE_PIN, HIGH);
        #endif

        #ifdef ULTIPANEL
          powersupply = true;
          LCD_MESSAGEPGM(WELCOME_MSG);
          lcd_update();
        #endif
        break;
      #endif

      case 81: // M81 - Turn off Power Supply
        disable_heater();
        st_synchronize();
        disable_e0();
        disable_e1();
        disable_e2();
        finishAndDisableSteppers();
        fanSpeed = 0;
        delay(1000); // Wait a little before to switch off
      #if defined(SUICIDE_PIN) && SUICIDE_PIN > -1
        st_synchronize();
        suicide();
      #elif defined(PS_ON_PIN) && PS_ON_PIN > -1
        OUT_WRITE(PS_ON_PIN, PS_ON_ASLEEP);
      #endif
      #ifdef ULTIPANEL
        powersupply = false;
        LCD_MESSAGEPGM(MACHINE_NAME" "MSG_OFF".");
        lcd_update();
      #endif
	  break;

    case 82:
      axis_relative_modes[3] = false;
      break;
    case 83:
      axis_relative_modes[3] = true;
      break;
    case 18: //compatibility
    case 84: // M84
      if(code_seen('S')){
        stepper_inactive_time = code_value() * 1000;
      }
      else
      {
        bool all_axis = !((code_seen(axis_codes[X_AXIS])) || (code_seen(axis_codes[Y_AXIS])) || (code_seen(axis_codes[Z_AXIS]))|| (code_seen(axis_codes[E_AXIS])));
        if(all_axis)
        {
          st_synchronize();
          disable_e0();
          disable_e1();
          disable_e2();
          finishAndDisableSteppers();
        }
        else
        {
          st_synchronize();
          if(code_seen('X')) disable_x();
          if(code_seen('Y')) disable_y();
          if(code_seen('Z')) disable_z();
          #if ((E0_ENABLE_PIN != X_ENABLE_PIN) && (E1_ENABLE_PIN != Y_ENABLE_PIN)) // Only enable on boards that have seperate ENABLE_PINS
            if(code_seen('E')) {
              disable_e0();
              disable_e1();
              disable_e2();
            }
          #endif
        }
      }
      break;
    case 85: // M85
      if(code_seen('S')) {
        max_inactive_time = code_value() * 1000;
      }
      break;
    case 92: // M92
      for(int8_t i=0; i < NUM_AXIS; i++)
      {
        if(code_seen(axis_codes[i]))
        {
          if(i == 3) { // E
            float value = code_value();
            if(value < 20.0) {
              float factor = axis_steps_per_unit[i] / value; // increase e constants if M92 E14 is given for netfab.
              max_e_jerk *= factor;
              max_feedrate[i] *= factor;
              axis_steps_per_sqr_second[i] *= factor;
            }
            axis_steps_per_unit[i] = value;
          }
          else {
            axis_steps_per_unit[i] = code_value();
          }
        }
      }
      break;
    case 115: // M115
      SERIAL_PROTOCOLPGM(MSG_M115_REPORT);
      break;
    case 117: // M117 display message
      starpos = (strchr(strchr_pointer + 5,'*'));
      if(starpos!=NULL)
        *(starpos)='\0';
      lcd_setstatus(strchr_pointer + 5);
      break;
    case 114: // M114
      SERIAL_PROTOCOLPGM("X:");
      SERIAL_PROTOCOL(current_position[X_AXIS]);
      SERIAL_PROTOCOLPGM(" Y:");
      SERIAL_PROTOCOL(current_position[Y_AXIS]);
      SERIAL_PROTOCOLPGM(" Z:");
      SERIAL_PROTOCOL(current_position[Z_AXIS]);
      SERIAL_PROTOCOLPGM(" E:");
      SERIAL_PROTOCOL(current_position[E_AXIS]);

      SERIAL_PROTOCOLPGM(MSG_COUNT_X);
      SERIAL_PROTOCOL(float(st_get_position(X_AXIS))/axis_steps_per_unit[X_AXIS]);
      SERIAL_PROTOCOLPGM(" Y:");
      SERIAL_PROTOCOL(float(st_get_position(Y_AXIS))/axis_steps_per_unit[Y_AXIS]);
      SERIAL_PROTOCOLPGM(" Z:");
      SERIAL_PROTOCOL(float(st_get_position(Z_AXIS))/axis_steps_per_unit[Z_AXIS]);

      SERIAL_PROTOCOLLN("");
#ifdef SCARA
	  SERIAL_PROTOCOLPGM("SCARA Theta:");
      SERIAL_PROTOCOL(delta[X_AXIS]);
      SERIAL_PROTOCOLPGM("   Psi+Theta:");
      SERIAL_PROTOCOL(delta[Y_AXIS]);
      SERIAL_PROTOCOLLN("");
      
      SERIAL_PROTOCOLPGM("SCARA Cal - Theta:");
      SERIAL_PROTOCOL(delta[X_AXIS]+add_homing[X_AXIS]);
      SERIAL_PROTOCOLPGM("   Psi+Theta (90):");
      SERIAL_PROTOCOL(delta[Y_AXIS]-delta[X_AXIS]-90+add_homing[Y_AXIS]);
      SERIAL_PROTOCOLLN("");
      
      SERIAL_PROTOCOLPGM("SCARA step Cal - Theta:");
      SERIAL_PROTOCOL(delta[X_AXIS]/90*axis_steps_per_unit[X_AXIS]);
      SERIAL_PROTOCOLPGM("   Psi+Theta:");
      SERIAL_PROTOCOL((delta[Y_AXIS]-delta[X_AXIS])/90*axis_steps_per_unit[Y_AXIS]);
      SERIAL_PROTOCOLLN("");
      SERIAL_PROTOCOLLN("");
#endif
      break;
    case 120: // M120
      enable_endstops(false) ;
      break;
    case 121: // M121
      enable_endstops(true) ;
      break;
    case 119: // M119
    SERIAL_PROTOCOLLN(MSG_M119_REPORT);
      #if defined(X_MIN_PIN) && X_MIN_PIN > -1
        SERIAL_PROTOCOLPGM(MSG_X_MIN);
        SERIAL_PROTOCOLLN(((READ(X_MIN_PIN)^X_MIN_ENDSTOP_INVERTING)?MSG_ENDSTOP_HIT:MSG_ENDSTOP_OPEN));
      #endif
      #if defined(X_MAX_PIN) && X_MAX_PIN > -1
        SERIAL_PROTOCOLPGM(MSG_X_MAX);
        SERIAL_PROTOCOLLN(((READ(X_MAX_PIN)^X_MAX_ENDSTOP_INVERTING)?MSG_ENDSTOP_HIT:MSG_ENDSTOP_OPEN));
      #endif
      #if defined(Y_MIN_PIN) && Y_MIN_PIN > -1
        SERIAL_PROTOCOLPGM(MSG_Y_MIN);
        SERIAL_PROTOCOLLN(((READ(Y_MIN_PIN)^Y_MIN_ENDSTOP_INVERTING)?MSG_ENDSTOP_HIT:MSG_ENDSTOP_OPEN));
      #endif
      #if defined(Y_MAX_PIN) && Y_MAX_PIN > -1
        SERIAL_PROTOCOLPGM(MSG_Y_MAX);
        SERIAL_PROTOCOLLN(((READ(Y_MAX_PIN)^Y_MAX_ENDSTOP_INVERTING)?MSG_ENDSTOP_HIT:MSG_ENDSTOP_OPEN));
      #endif
      #if defined(Z_MIN_PIN) && Z_MIN_PIN > -1
        SERIAL_PROTOCOLPGM(MSG_Z_MIN);
        SERIAL_PROTOCOLLN(((READ(Z_MIN_PIN)^Z_MIN_ENDSTOP_INVERTING)?MSG_ENDSTOP_HIT:MSG_ENDSTOP_OPEN));
      #endif
      #if defined(Z_MAX_PIN) && Z_MAX_PIN > -1
        SERIAL_PROTOCOLPGM(MSG_Z_MAX);
        SERIAL_PROTOCOLLN(((READ(Z_MAX_PIN)^Z_MAX_ENDSTOP_INVERTING)?MSG_ENDSTOP_HIT:MSG_ENDSTOP_OPEN));
      #endif
      break;
      //TODO: update for all axis, use for loop
    #ifdef BLINKM
    case 150: // M150
      {
        byte red;
        byte grn;
        byte blu;

        if(code_seen('R')) red = code_value();
        if(code_seen('U')) grn = code_value();
        if(code_seen('B')) blu = code_value();

        SendColors(red,grn,blu);
      }
      break;
    #endif //BLINKM
    case 200: // M200 D<millimeters> set filament diameter and set E axis units to cubic millimeters (use S0 to set back to millimeters).
      {

        tmp_extruder = active_extruder;
        if(code_seen('T')) {
          tmp_extruder = code_value();
          if(tmp_extruder >= EXTRUDERS) {
            SERIAL_ECHO_START;
            SERIAL_ECHO(MSG_M200_INVALID_EXTRUDER);
            break;
          }
        }

        float area = .0;
        if(code_seen('D')) {
          float diameter = code_value();
          // setting any extruder filament size disables volumetric on the assumption that
          // slicers either generate in extruder values as cubic mm or as as filament feeds
          // for all extruders
          volumetric_enabled = (diameter != 0.0);
          if (volumetric_enabled) {
            filament_size[tmp_extruder] = diameter;
            // make sure all extruders have some sane value for the filament size
            for (int i=0; i<EXTRUDERS; i++)
              if (! filament_size[i]) filament_size[i] = DEFAULT_NOMINAL_FILAMENT_DIA;
          }
        } else {
          //reserved for setting filament diameter via UFID or filament measuring device
          break;
        }
        calculate_volumetric_multipliers();
      }
      break;
    case 201: // M201
      for(int8_t i=0; i < NUM_AXIS; i++)
      {
        if(code_seen(axis_codes[i]))
        {
          max_acceleration_units_per_sq_second[i] = code_value();
        }
      }
      // steps per sq second need to be updated to agree with the units per sq second (as they are what is used in the planner)
      reset_acceleration_rates();
      break;
    #if 0 // Not used for Sprinter/grbl gen6
    case 202: // M202
      for(int8_t i=0; i < NUM_AXIS; i++) {
        if(code_seen(axis_codes[i])) axis_travel_steps_per_sqr_second[i] = code_value() * axis_steps_per_unit[i];
      }
      break;
    #endif
    case 203: // M203 max feedrate mm/sec
      for(int8_t i=0; i < NUM_AXIS; i++) {
        if(code_seen(axis_codes[i])) max_feedrate[i] = code_value();
      }
      break;
    case 204: // M204 acclereration S normal moves T filmanent only moves
      {
        if(code_seen('S')) acceleration = code_value() ;
        if(code_seen('T')) retract_acceleration = code_value() ;
      }
      break;
    case 205: //M205 advanced settings:  minimum travel speed S=while printing T=travel only,  B=minimum segment time X= maximum xy jerk, Z=maximum Z jerk
    {
      if(code_seen('S')) minimumfeedrate = code_value();
      if(code_seen('T')) mintravelfeedrate = code_value();
      if(code_seen('B')) minsegmenttime = code_value() ;
      if(code_seen('X')) max_xy_jerk = code_value() ;
      if(code_seen('Z')) max_z_jerk = code_value() ;
      if(code_seen('E')) max_e_jerk = code_value() ;
    }
    break;
    case 206: // M206 additional homing offset
      for(int8_t i=0; i < 3; i++)
      {
        if(code_seen(axis_codes[i])) add_homing[i] = code_value();
      }
	  #ifdef SCARA
	   if(code_seen('T'))       // Theta
      {
        add_homing[X_AXIS] = code_value() ;
      }
      if(code_seen('P'))       // Psi
      {
        add_homing[Y_AXIS] = code_value() ;
      }
	  #endif
      break;
    #ifdef DELTA
	case 665: // M665 set delta configurations L<diagonal_rod> R<delta_radius> S<segments_per_sec>
		if(code_seen('L')) {
			delta_diagonal_rod= code_value();
		}
		if(code_seen('R')) {
			delta_radius= code_value();
		}
		if(code_seen('S')) {
			delta_segments_per_second= code_value();
		}
		
		recalc_delta_settings(delta_radius, delta_diagonal_rod);
		break;
    case 666: // M666 set delta endstop adjustemnt
      for(int8_t i=0; i < 3; i++)
      {
        if(code_seen(axis_codes[i])) endstop_adj[i] = code_value();
      }
      break;
    #endif
    #ifdef FWRETRACT
    case 207: //M207 - set retract length S[positive mm] F[feedrate mm/min] Z[additional zlift/hop]
    {
      if(code_seen('S'))
      {
        retract_length = code_value() ;
      }
      if(code_seen('F'))
      {
        retract_feedrate = code_value()/60 ;
      }
      if(code_seen('Z'))
      {
        retract_zlift = code_value() ;
      }
    }break;
    case 208: // M208 - set retract recover length S[positive mm surplus to the M207 S*] F[feedrate mm/min]
    {
      if(code_seen('S'))
      {
        retract_recover_length = code_value() ;
      }
      if(code_seen('F'))
      {
        retract_recover_feedrate = code_value()/60 ;
      }
    }break;
    case 209: // M209 - S<1=true/0=false> enable automatic retract detect if the slicer did not support G10/11: every normal extrude-only move will be classified as retract depending on the direction.
    {
      if(code_seen('S'))
      {
        int t= code_value() ;
        switch(t)
        {
          case 0:
          case 1:
          {
            autoretract_enabled = (t == 1);
            for (int i=0; i<EXTRUDERS; i++) retracted[i] = false;
          }break;
          default:
            SERIAL_ECHO_START;
            SERIAL_ECHOPGM(MSG_UNKNOWN_COMMAND);
            SERIAL_ECHO(cmdbuffer[bufindr]);
            SERIAL_ECHOLNPGM("\"");
        }
      }

    }break;
    #endif // FWRETRACT
    #if EXTRUDERS > 1
    case 218: // M218 - set hotend offset (in mm), T<extruder_number> X<offset_on_X> Y<offset_on_Y>
    {
      if(setTargetedHotend(218)){
        break;
      }
      if(code_seen('X'))
      {
        extruder_offset[X_AXIS][tmp_extruder] = code_value();
      }
      if(code_seen('Y'))
      {
        extruder_offset[Y_AXIS][tmp_extruder] = code_value();
      }
      #ifdef DUAL_X_CARRIAGE
      if(code_seen('Z'))
      {
        extruder_offset[Z_AXIS][tmp_extruder] = code_value();
      }
      #endif
      SERIAL_ECHO_START;
      SERIAL_ECHOPGM(MSG_HOTEND_OFFSET);
      for(tmp_extruder = 0; tmp_extruder < EXTRUDERS; tmp_extruder++)
      {
         SERIAL_ECHO(" ");
         SERIAL_ECHO(extruder_offset[X_AXIS][tmp_extruder]);
         SERIAL_ECHO(",");
         SERIAL_ECHO(extruder_offset[Y_AXIS][tmp_extruder]);
      #ifdef DUAL_X_CARRIAGE
         SERIAL_ECHO(",");
         SERIAL_ECHO(extruder_offset[Z_AXIS][tmp_extruder]);
      #endif
      }
      SERIAL_EOL;
    }break;
    #endif
    case 220: // M220 S<factor in percent>- set speed factor override percentage
    {
      if(code_seen('S'))
      {
        feedmultiply = code_value() ;
      }
    }
    break;
    case 221: // M221 S<factor in percent>- set extrude factor override percentage
    {
      if(code_seen('S'))
      {
        int tmp_code = code_value();
        if (code_seen('T'))
        {
          if(setTargetedHotend(221)){
            break;
          }
          extruder_multiply[tmp_extruder] = tmp_code;
        }
        else
        {
          extrudemultiply = tmp_code ;
        }
      }
    }
    break;

	case 226: // M226 P<pin number> S<pin state>- Wait until the specified pin reaches the state required
	{
      if(code_seen('P')){
        int pin_number = code_value(); // pin number
        int pin_state = -1; // required pin state - default is inverted

        if(code_seen('S')) pin_state = code_value(); // required pin state

        if(pin_state >= -1 && pin_state <= 1){

          for(int8_t i = 0; i < (int8_t)(sizeof(sensitive_pins)/sizeof(int)); i++)
          {
            if (sensitive_pins[i] == pin_number)
            {
              pin_number = -1;
              break;
            }
          }

          if (pin_number > -1)
          {
            int target = LOW;

            st_synchronize();

            pinMode(pin_number, INPUT);

            switch(pin_state){
            case 1:
              target = HIGH;
              break;

            case 0:
              target = LOW;
              break;

            case -1:
              target = !digitalRead(pin_number);
              break;
            }

            while(digitalRead(pin_number) != target){
              manage_heater();
              manage_inactivity();
              lcd_update();
            }
          }
        }
      }
    }
    break;

    #if NUM_SERVOS > 0
    case 280: // M280 - set servo position absolute. P: servo index, S: angle or microseconds
      {
        int servo_index = -1;
        int servo_position = 0;
        if (code_seen('P'))
          servo_index = code_value();
        if (code_seen('S')) {
          servo_position = code_value();
          if ((servo_index >= 0) && (servo_index < NUM_SERVOS)) {
#if defined (ENABLE_AUTO_BED_LEVELING) && (PROBE_SERVO_DEACTIVATION_DELAY > 0)
		      servos[servo_index].attach(0);
#endif
            servos[servo_index].write(servo_position);
#if defined (ENABLE_AUTO_BED_LEVELING) && (PROBE_SERVO_DEACTIVATION_DELAY > 0)
              delay(PROBE_SERVO_DEACTIVATION_DELAY);
              servos[servo_index].detach();
#endif
          }
          else {
            SERIAL_ECHO_START;
            SERIAL_ECHO("Servo ");
            SERIAL_ECHO(servo_index);
            SERIAL_ECHOLN(" out of range");
          }
        }
        else if (servo_index >= 0) {
          SERIAL_PROTOCOL(MSG_OK);
          SERIAL_PROTOCOL(" Servo ");
          SERIAL_PROTOCOL(servo_index);
          SERIAL_PROTOCOL(": ");
          SERIAL_PROTOCOL(servos[servo_index].read());
          SERIAL_PROTOCOLLN("");
        }
      }
      break;
    #endif // NUM_SERVOS > 0

    #if (LARGE_FLASH == true && ( BEEPER > 0 || defined(ULTRALCD) || defined(LCD_USE_I2C_BUZZER)))
    case 300: // M300
    {
      int beepS = code_seen('S') ? code_value() : 110;
      int beepP = code_seen('P') ? code_value() : 1000;
      if (beepS > 0)
      {
        #if BEEPER > 0
          tone(BEEPER, beepS);
          delay(beepP);
          noTone(BEEPER);
        #elif defined(ULTRALCD)
		  lcd_buzz(beepS, beepP);
		#elif defined(LCD_USE_I2C_BUZZER)
		  lcd_buzz(beepP, beepS);
        #endif
      }
      else
      {
        delay(beepP);
      }
    }
    break;
    #endif // M300

    #ifdef PIDTEMP
	case 301: // M301
	{

		// multi-extruder PID patch: M301 updates or prints a single extruder's PID values
		// default behaviour (omitting E parameter) is to update for extruder 0 only
		int e = 0; // extruder being updated
		if (code_seen('E'))
		{
			e = (int)code_value();
		}
		if (e < EXTRUDERS) // catch bad input value
		{

			if (code_seen('P')) PID_PARAM(Kp,e) = code_value();
			if (code_seen('I')) PID_PARAM(Ki,e) = scalePID_i(code_value());
			if (code_seen('D')) PID_PARAM(Kd,e) = scalePID_d(code_value());
			#ifdef PID_ADD_EXTRUSION_RATE
			if (code_seen('C')) PID_PARAM(Kc,e) = code_value();
			#endif			

			updatePID();
			SERIAL_PROTOCOL(MSG_OK);
            #ifdef PID_PARAMS_PER_EXTRUDER
			  SERIAL_PROTOCOL(" e:"); // specify extruder in serial output
			  SERIAL_PROTOCOL(e);
            #endif // PID_PARAMS_PER_EXTRUDER
			SERIAL_PROTOCOL(" p:");
			SERIAL_PROTOCOL(PID_PARAM(Kp,e));
			SERIAL_PROTOCOL(" i:");
			SERIAL_PROTOCOL(unscalePID_i(PID_PARAM(Ki,e)));
			SERIAL_PROTOCOL(" d:");
			SERIAL_PROTOCOL(unscalePID_d(PID_PARAM(Kd,e)));
			#ifdef PID_ADD_EXTRUSION_RATE
			SERIAL_PROTOCOL(" c:");
			//Kc does not have scaling applied above, or in resetting defaults
			SERIAL_PROTOCOL(PID_PARAM(Kc,e));
			#endif
			SERIAL_PROTOCOLLN("");
		
		}
		else
		{
			SERIAL_ECHO_START;
			SERIAL_ECHOLN(MSG_INVALID_EXTRUDER);
		}

      }
      break;
    #endif //PIDTEMP
    #ifdef PIDTEMPBED
    case 304: // M304
      {
        if(code_seen('P')) bedKp = code_value();
        if(code_seen('I')) bedKi = scalePID_i(code_value());
        if(code_seen('D')) bedKd = scalePID_d(code_value());

        updatePID();
        SERIAL_PROTOCOL(MSG_OK);
        SERIAL_PROTOCOL(" p:");
        SERIAL_PROTOCOL(bedKp);
        SERIAL_PROTOCOL(" i:");
        SERIAL_PROTOCOL(unscalePID_i(bedKi));
        SERIAL_PROTOCOL(" d:");
        SERIAL_PROTOCOL(unscalePID_d(bedKd));
        SERIAL_PROTOCOLLN("");
      }
      break;
    #endif //PIDTEMP
    case 240: // M240  Triggers a camera by emulating a Canon RC-1 : http://www.doc-diy.net/photo/rc-1_hacked/
     {
     	#ifdef CHDK
       
         OUT_WRITE(CHDK, HIGH);
         chdkHigh = millis();
         chdkActive = true;
       
       #else
     	
      	#if defined(PHOTOGRAPH_PIN) && PHOTOGRAPH_PIN > -1
	const uint8_t NUM_PULSES=16;
	const float PULSE_LENGTH=0.01524;
	for(int i=0; i < NUM_PULSES; i++) {
        WRITE(PHOTOGRAPH_PIN, HIGH);
        _delay_ms(PULSE_LENGTH);
        WRITE(PHOTOGRAPH_PIN, LOW);
        _delay_ms(PULSE_LENGTH);
        }
        delay(7.33);
        for(int i=0; i < NUM_PULSES; i++) {
        WRITE(PHOTOGRAPH_PIN, HIGH);
        _delay_ms(PULSE_LENGTH);
        WRITE(PHOTOGRAPH_PIN, LOW);
        _delay_ms(PULSE_LENGTH);
        }
      	#endif
      #endif //chdk end if
     }
    break;
#ifdef DOGLCD
    case 250: // M250  Set LCD contrast value: C<value> (value 0..63)
     {
	  if (code_seen('C')) {
	   lcd_setcontrast( ((int)code_value())&63 );
          }
          SERIAL_PROTOCOLPGM("lcd contrast value: ");
          SERIAL_PROTOCOL(lcd_contrast);
          SERIAL_PROTOCOLLN("");
     }
    break;
#endif
    #ifdef PREVENT_DANGEROUS_EXTRUDE
    case 302: // allow cold extrudes, or set the minimum extrude temperature
    {
	  float temp = .0;
	  if (code_seen('S')) temp=code_value();
      set_extrude_min_temp(temp);
    }
    break;
	#endif
    case 303: // M303 PID autotune
    {
      float temp = 150.0;
      int e=0;
      int c=5;
      if (code_seen('E')) e=code_value();
        if (e<0)
          temp=70;
      if (code_seen('S')) temp=code_value();
      if (code_seen('C')) c=code_value();
      PID_autotune(temp, e, c);
    }
    break;
	#ifdef SCARA
	case 360:  // M360 SCARA Theta pos1
      SERIAL_ECHOLN(" Cal: Theta 0 ");
      //SoftEndsEnabled = false;              // Ignore soft endstops during calibration
      //SERIAL_ECHOLN(" Soft endstops disabled ");
      if(Stopped == false) {
        //get_coordinates(); // For X Y Z E F
        delta[X_AXIS] = 0;
        delta[Y_AXIS] = 120;
        calculate_SCARA_forward_Transform(delta);
        destination[X_AXIS] = delta[X_AXIS]/axis_scaling[X_AXIS];
        destination[Y_AXIS] = delta[Y_AXIS]/axis_scaling[Y_AXIS];
        
        prepare_move();
        //ClearToSend();
        return;
      }
    break;

    case 361:  // SCARA Theta pos2
      SERIAL_ECHOLN(" Cal: Theta 90 ");
      //SoftEndsEnabled = false;              // Ignore soft endstops during calibration
      //SERIAL_ECHOLN(" Soft endstops disabled ");
      if(Stopped == false) {
        //get_coordinates(); // For X Y Z E F
        delta[X_AXIS] = 90;
        delta[Y_AXIS] = 130;
        calculate_SCARA_forward_Transform(delta);
        destination[X_AXIS] = delta[X_AXIS]/axis_scaling[X_AXIS];
        destination[Y_AXIS] = delta[Y_AXIS]/axis_scaling[Y_AXIS];
        
        prepare_move();
        //ClearToSend();
        return;
      }
    break;
    case 362:  // SCARA Psi pos1
      SERIAL_ECHOLN(" Cal: Psi 0 ");
      //SoftEndsEnabled = false;              // Ignore soft endstops during calibration
      //SERIAL_ECHOLN(" Soft endstops disabled ");
      if(Stopped == false) {
        //get_coordinates(); // For X Y Z E F
        delta[X_AXIS] = 60;
        delta[Y_AXIS] = 180;
        calculate_SCARA_forward_Transform(delta);
        destination[X_AXIS] = delta[X_AXIS]/axis_scaling[X_AXIS];
        destination[Y_AXIS] = delta[Y_AXIS]/axis_scaling[Y_AXIS];
        
        prepare_move();
        //ClearToSend();
        return;
      }
    break;
    case 363:  // SCARA Psi pos2
      SERIAL_ECHOLN(" Cal: Psi 90 ");
      //SoftEndsEnabled = false;              // Ignore soft endstops during calibration
      //SERIAL_ECHOLN(" Soft endstops disabled ");
      if(Stopped == false) {
        //get_coordinates(); // For X Y Z E F
        delta[X_AXIS] = 50;
        delta[Y_AXIS] = 90;
        calculate_SCARA_forward_Transform(delta);
        destination[X_AXIS] = delta[X_AXIS]/axis_scaling[X_AXIS];
        destination[Y_AXIS] = delta[Y_AXIS]/axis_scaling[Y_AXIS];
        
        prepare_move();
        //ClearToSend();
        return;
      }
    break;
    case 364:  // SCARA Psi pos3 (90 deg to Theta)
      SERIAL_ECHOLN(" Cal: Theta-Psi 90 ");
     // SoftEndsEnabled = false;              // Ignore soft endstops during calibration
      //SERIAL_ECHOLN(" Soft endstops disabled ");
      if(Stopped == false) {
        //get_coordinates(); // For X Y Z E F
        delta[X_AXIS] = 45;
        delta[Y_AXIS] = 135;
        calculate_SCARA_forward_Transform(delta);
        destination[X_AXIS] = delta[X_AXIS]/axis_scaling[X_AXIS];
        destination[Y_AXIS] = delta[Y_AXIS]/axis_scaling[Y_AXIS]; 
        
        prepare_move();
        //ClearToSend();
        return;
      }
    break;
    case 365: // M364  Set SCARA scaling for X Y Z
      for(int8_t i=0; i < 3; i++) 
      {
        if(code_seen(axis_codes[i])) 
        {
          
            axis_scaling[i] = code_value();
          
        }
      }
      break;
	#endif
    
#ifdef EXT_SOLENOID
    case 380:
        enable_solenoid_on_active_extruder();
        break;

    case 381:
        disable_all_solenoids();
        break;
#endif //EXT_SOLENOID

    case 400: // M400 finish all moves
    {
      st_synchronize();
    }
    break;
#if defined(ENABLE_AUTO_BED_LEVELING) && defined(SERVO_ENDSTOPS) && not defined(Z_PROBE_SLED)
    case 401:
    {
        engage_z_probe();    // Engage Z Servo endstop if available
    }
    break;

    case 402:
    {
        retract_z_probe();    // Retract Z Servo endstop if enabled
    }
    break;
#endif

#ifdef FILAMENT_SENSOR
case 404:  //M404 Enter the nominal filament width (3mm, 1.75mm ) N<3.0> or display nominal filament width 
    {
    #if (FILWIDTH_PIN > -1) 
    if(code_seen('N')) filament_width_nominal=code_value();
    else{
    SERIAL_PROTOCOLPGM("Filament dia (nominal mm):"); 
    SERIAL_PROTOCOLLN(filament_width_nominal); 
    }
    #endif
    }
    break; 
    
    case 405:  //M405 Turn on filament sensor for control 
    {
    
    
    if(code_seen('D')) meas_delay_cm=code_value();
       
       if(meas_delay_cm> MAX_MEASUREMENT_DELAY)
       	meas_delay_cm = MAX_MEASUREMENT_DELAY;
    
       if(delay_index2 == -1)  //initialize the ring buffer if it has not been done since startup
    	   {
    	   int temp_ratio = widthFil_to_size_ratio(); 
       	    
       	    for (delay_index1=0; delay_index1<(MAX_MEASUREMENT_DELAY+1); ++delay_index1 ){
       	              measurement_delay[delay_index1]=temp_ratio-100;  //subtract 100 to scale within a signed byte
       	        }
       	    delay_index1=0;
       	    delay_index2=0;	
    	   }
    
    filament_sensor = true ; 
    
    //SERIAL_PROTOCOLPGM("Filament dia (measured mm):"); 
    //SERIAL_PROTOCOL(filament_width_meas); 
    //SERIAL_PROTOCOLPGM("Extrusion ratio(%):"); 
    //SERIAL_PROTOCOL(extrudemultiply); 
    } 
    break; 
    
    case 406:  //M406 Turn off filament sensor for control 
    {      
    filament_sensor = false ; 
    } 
    break; 
  
    case 407:   //M407 Display measured filament diameter 
    { 
     
    
    
    SERIAL_PROTOCOLPGM("Filament dia (measured mm):"); 
    SERIAL_PROTOCOLLN(filament_width_meas);   
    } 
    break; 
    #endif
    




    case 500: // M500 Store settings in EEPROM
    {
        Config_StoreSettings();
    }
    break;
    case 501: // M501 Read settings from EEPROM
    {
        Config_RetrieveSettings();
    }
    break;
    case 502: // M502 Revert to default settings
    {
        Config_ResetDefault();
    }
    break;
    case 503: // M503 print settings currently in memory
    {
        Config_PrintSettings(code_seen('S') && code_value == 0);
    }
    break;
    #ifdef ABORT_ON_ENDSTOP_HIT_FEATURE_ENABLED
    case 540:
    {
        if(code_seen('S')) abort_on_endstop_hit = code_value() > 0;
    }
    break;
    #endif

    #ifdef CUSTOM_M_CODE_SET_Z_PROBE_OFFSET
    case CUSTOM_M_CODE_SET_Z_PROBE_OFFSET:
    {
      float value;
      if (code_seen('Z'))
      {
        value = code_value();
        if ((Z_PROBE_OFFSET_RANGE_MIN <= value) && (value <= Z_PROBE_OFFSET_RANGE_MAX))
        {
          zprobe_zoffset = -value; // compare w/ line 278 of ConfigurationStore.cpp
          SERIAL_ECHO_START;
          SERIAL_ECHOLNPGM(MSG_ZPROBE_ZOFFSET " " MSG_OK);
          SERIAL_PROTOCOLLN("");
        }
        else
        {
          SERIAL_ECHO_START;
          SERIAL_ECHOPGM(MSG_ZPROBE_ZOFFSET);
          SERIAL_ECHOPGM(MSG_Z_MIN);
          SERIAL_ECHO(Z_PROBE_OFFSET_RANGE_MIN);
          SERIAL_ECHOPGM(MSG_Z_MAX);
          SERIAL_ECHO(Z_PROBE_OFFSET_RANGE_MAX);
          SERIAL_PROTOCOLLN("");
        }
      }
      else
      {
          SERIAL_ECHO_START;
          SERIAL_ECHOLNPGM(MSG_ZPROBE_ZOFFSET " : ");
          SERIAL_ECHO(-zprobe_zoffset);
          SERIAL_PROTOCOLLN("");
      }
      break;
    }
    #endif // CUSTOM_M_CODE_SET_Z_PROBE_OFFSET

    #ifdef FILAMENTCHANGEENABLE
    case 600: //Pause for filament change X[pos] Y[pos] Z[relative lift] E[initial retract] L[later retract distance for removal]
    {
        float target[NUM_AXIS], lastpos[NUM_AXIS], fr60 = feedrate/60;
        for (int i=0; i<NUM_AXIS; i++)
          target[i] = lastpos[i] = current_position[i];

        #define BASICPLAN plan_buffer_line(target[X_AXIS], target[Y_AXIS], target[Z_AXIS], target[E_AXIS], fr60, active_extruder);
        #ifdef DELTA
          #define RUNPLAN calculate_delta(target); BASICPLAN
        #else
          #define RUNPLAN BASICPLAN
        #endif

        //retract by E
        if(code_seen('E'))
        {
          target[E_AXIS]+= code_value();
        }
        else
        {
          #ifdef FILAMENTCHANGE_FIRSTRETRACT
            target[E_AXIS]+= FILAMENTCHANGE_FIRSTRETRACT ;
          #endif
        }
        RUNPLAN;

        //lift Z
        if(code_seen('Z'))
        {
          target[Z_AXIS]+= code_value();
        }
        else
        {
          #ifdef FILAMENTCHANGE_ZADD
            target[Z_AXIS]+= FILAMENTCHANGE_ZADD ;
          #endif
        }
        RUNPLAN;

        //move xy
        if(code_seen('X'))
        {
          target[X_AXIS]= code_value();
        }
        else
        {
          #ifdef FILAMENTCHANGE_XPOS
            target[X_AXIS]= FILAMENTCHANGE_XPOS ;
          #endif
        }
        if(code_seen('Y'))
        {
          target[Y_AXIS]= code_value();
        }
        else
        {
          #ifdef FILAMENTCHANGE_YPOS
            target[Y_AXIS]= FILAMENTCHANGE_YPOS ;
          #endif
        }

        RUNPLAN;

        if(code_seen('L'))
        {
          target[E_AXIS]+= code_value();
        }
        else
        {
          #ifdef FILAMENTCHANGE_FINALRETRACT
            target[E_AXIS]+= FILAMENTCHANGE_FINALRETRACT ;
          #endif
        }

        RUNPLAN;

        //finish moves
        st_synchronize();
        //disable extruder steppers so filament can be removed
        disable_e0();
        disable_e1();
        disable_e2();
        delay(100);
        LCD_ALERTMESSAGEPGM(MSG_FILAMENTCHANGE);
        uint8_t cnt=0;
        while(!lcd_clicked()){
          cnt++;
          manage_heater();
          manage_inactivity(true);
          lcd_update();
          if(cnt==0)
          {
          #if BEEPER > 0
            OUT_WRITE(BEEPER,HIGH);
            delay(3);
            WRITE(BEEPER,LOW);
            delay(3);
          #else
			#if !defined(LCD_FEEDBACK_FREQUENCY_HZ) || !defined(LCD_FEEDBACK_FREQUENCY_DURATION_MS)
              lcd_buzz(1000/6,100);
			#else
			  lcd_buzz(LCD_FEEDBACK_FREQUENCY_DURATION_MS,LCD_FEEDBACK_FREQUENCY_HZ);
			#endif
          #endif
          }
        }

        //return to normal
        if(code_seen('L'))
        {
          target[E_AXIS]+= -code_value();
        }
        else
        {
          #ifdef FILAMENTCHANGE_FINALRETRACT
            target[E_AXIS]+=(-1)*FILAMENTCHANGE_FINALRETRACT ;
          #endif
        }
        current_position[E_AXIS]=target[E_AXIS]; //the long retract of L is compensated by manual filament feeding
        plan_set_e_position(current_position[E_AXIS]);

        RUNPLAN; //should do nothing

        //reset LCD alert message
    	lcd_reset_alert_level();

        #ifdef DELTA
          calculate_delta(lastpos);
          plan_buffer_line(delta[X_AXIS], delta[Y_AXIS], delta[Z_AXIS], target[E_AXIS], fr60, active_extruder); //move xyz back
          plan_buffer_line(delta[X_AXIS], delta[Y_AXIS], delta[Z_AXIS], lastpos[E_AXIS], fr60, active_extruder); //final untretract
        #else
          plan_buffer_line(lastpos[X_AXIS], lastpos[Y_AXIS], target[Z_AXIS], target[E_AXIS], fr60, active_extruder); //move xy back
          plan_buffer_line(lastpos[X_AXIS], lastpos[Y_AXIS], lastpos[Z_AXIS], target[E_AXIS], fr60, active_extruder); //move z back
          plan_buffer_line(lastpos[X_AXIS], lastpos[Y_AXIS], lastpos[Z_AXIS], lastpos[E_AXIS], fr60, active_extruder); //final untretract
        #endif
    }
    break;
    #endif //FILAMENTCHANGEENABLE
    #ifdef DUAL_X_CARRIAGE
    case 605: // Set dual x-carriage movement mode:
              //    M605 S0: Full control mode. The slicer has full control over x-carriage movement
              //    M605 S1: Auto-park mode. The inactive head will auto park/unpark without slicer involvement
              //    M605 S2 [Xnnn] [Rmmm]: Duplication mode. The second extruder will duplicate the first with nnn
              //                         millimeters x-offset and an optional differential hotend temperature of
              //                         mmm degrees. E.g., with "M605 S2 X100 R2" the second extruder will duplicate
              //                         the first with a spacing of 100mm in the x direction and 2 degrees hotter.
              //
              //    Note: the X axis should be homed after changing dual x-carriage mode.
    {
        st_synchronize();

        if (code_seen('S'))
          dual_x_carriage_mode = code_value();

        if (dual_x_carriage_mode == DXC_DUPLICATION_MODE)
        {
          if (code_seen('X'))
            duplicate_extruder_x_offset = max(code_value(),X2_MIN_POS - x_home_pos(0));

          if (code_seen('R'))
            duplicate_extruder_temp_offset = code_value();

          SERIAL_ECHO_START;
          SERIAL_ECHOPGM(MSG_HOTEND_OFFSET);
          SERIAL_ECHO(" ");
          SERIAL_ECHO(extruder_offset[X_AXIS][0]);
          SERIAL_ECHO(",");
          SERIAL_ECHO(extruder_offset[Y_AXIS][0]);
          SERIAL_ECHO(" ");
          SERIAL_ECHO(duplicate_extruder_x_offset);
          SERIAL_ECHO(",");
          SERIAL_ECHOLN(extruder_offset[Y_AXIS][1]);
        }
        else if (dual_x_carriage_mode != DXC_FULL_CONTROL_MODE && dual_x_carriage_mode != DXC_AUTO_PARK_MODE)
        {
          dual_x_carriage_mode = DEFAULT_DUAL_X_CARRIAGE_MODE;
        }

        active_extruder_parked = false;
        extruder_duplication_enabled = false;
        delayed_move_time = 0;
    }
    break;
    #endif //DUAL_X_CARRIAGE

    case 907: // M907 Set digital trimpot motor current using axis codes.
    {
      #if defined(DIGIPOTSS_PIN) && DIGIPOTSS_PIN > -1
        for(int i=0;i<NUM_AXIS;i++) if(code_seen(axis_codes[i])) digipot_current(i,code_value());
        if(code_seen('B')) digipot_current(4,code_value());
        if(code_seen('S')) for(int i=0;i<=4;i++) digipot_current(i,code_value());
      #endif
      #ifdef MOTOR_CURRENT_PWM_XY_PIN
        if(code_seen('X')) digipot_current(0, code_value());
      #endif
      #ifdef MOTOR_CURRENT_PWM_Z_PIN
        if(code_seen('Z')) digipot_current(1, code_value());
      #endif
      #ifdef MOTOR_CURRENT_PWM_E_PIN
        if(code_seen('E')) digipot_current(2, code_value());
      #endif
      #ifdef DIGIPOT_I2C
        // this one uses actual amps in floating point
        for(int i=0;i<NUM_AXIS;i++) if(code_seen(axis_codes[i])) digipot_i2c_set_current(i, code_value());
        // for each additional extruder (named B,C,D,E..., channels 4,5,6,7...)
        for(int i=NUM_AXIS;i<DIGIPOT_I2C_NUM_CHANNELS;i++) if(code_seen('B'+i-NUM_AXIS)) digipot_i2c_set_current(i, code_value());
      #endif
    }
    break;
    case 908: // M908 Control digital trimpot directly.
    {
      #if defined(DIGIPOTSS_PIN) && DIGIPOTSS_PIN > -1
        uint8_t channel,current;
        if(code_seen('P')) channel=code_value();
        if(code_seen('S')) current=code_value();
        digitalPotWrite(channel, current);
      #endif
    }
    break;
    case 350: // M350 Set microstepping mode. Warning: Steps per unit remains unchanged. S code sets stepping mode for all drivers.
    {
      #if defined(X_MS1_PIN) && X_MS1_PIN > -1
        if(code_seen('S')) for(int i=0;i<=4;i++) microstep_mode(i,code_value());
        for(int i=0;i<NUM_AXIS;i++) if(code_seen(axis_codes[i])) microstep_mode(i,(uint8_t)code_value());
        if(code_seen('B')) microstep_mode(4,code_value());
        microstep_readings();
      #endif
    }
    break;
    case 351: // M351 Toggle MS1 MS2 pins directly, S# determines MS1 or MS2, X# sets the pin high/low.
    {
      #if defined(X_MS1_PIN) && X_MS1_PIN > -1
      if(code_seen('S')) switch((int)code_value())
      {
        case 1:
          for(int i=0;i<NUM_AXIS;i++) if(code_seen(axis_codes[i])) microstep_ms(i,code_value(),-1);
          if(code_seen('B')) microstep_ms(4,code_value(),-1);
          break;
        case 2:
          for(int i=0;i<NUM_AXIS;i++) if(code_seen(axis_codes[i])) microstep_ms(i,-1,code_value());
          if(code_seen('B')) microstep_ms(4,-1,code_value());
          break;
      }
      microstep_readings();
      #endif
    }
    break;
    case 999: // M999: Restart after being stopped
      Stopped = false;
      lcd_reset_alert_level();
      gcode_LastN = Stopped_gcode_LastN;
      FlushSerialRequestResend();
    break;
    }
  }

  else if(code_seen('T'))
  {
    tmp_extruder = code_value();
    if(tmp_extruder >= EXTRUDERS) {
      SERIAL_ECHO_START;
      SERIAL_ECHO("T");
      SERIAL_ECHO(tmp_extruder);
      SERIAL_ECHOLN(MSG_INVALID_EXTRUDER);
    }
    else {
      boolean make_move = false;
      if(code_seen('F')) {
        make_move = true;
        next_feedrate = code_value();
        if(next_feedrate > 0.0) {
          feedrate = next_feedrate;
        }
      }
      #if EXTRUDERS > 1
      if(tmp_extruder != active_extruder) {
        // Save current position to return to after applying extruder offset
        memcpy(destination, current_position, sizeof(destination));
      #ifdef DUAL_X_CARRIAGE
        if (dual_x_carriage_mode == DXC_AUTO_PARK_MODE && Stopped == false &&
            (delayed_move_time != 0 || current_position[X_AXIS] != x_home_pos(active_extruder)))
        {
          // Park old head: 1) raise 2) move to park position 3) lower
          plan_buffer_line(current_position[X_AXIS], current_position[Y_AXIS], current_position[Z_AXIS] + TOOLCHANGE_PARK_ZLIFT,
                current_position[E_AXIS], max_feedrate[Z_AXIS], active_extruder);
          plan_buffer_line(x_home_pos(active_extruder), current_position[Y_AXIS], current_position[Z_AXIS] + TOOLCHANGE_PARK_ZLIFT,
                current_position[E_AXIS], max_feedrate[X_AXIS], active_extruder);
          plan_buffer_line(x_home_pos(active_extruder), current_position[Y_AXIS], current_position[Z_AXIS],
                current_position[E_AXIS], max_feedrate[Z_AXIS], active_extruder);
          st_synchronize();
        }

        // apply Y & Z extruder offset (x offset is already used in determining home pos)
        current_position[Y_AXIS] = current_position[Y_AXIS] -
                     extruder_offset[Y_AXIS][active_extruder] +
                     extruder_offset[Y_AXIS][tmp_extruder];
        current_position[Z_AXIS] = current_position[Z_AXIS] -
                     extruder_offset[Z_AXIS][active_extruder] +
                     extruder_offset[Z_AXIS][tmp_extruder];

        active_extruder = tmp_extruder;

        // This function resets the max/min values - the current position may be overwritten below.
        axis_is_at_home(X_AXIS);

        if (dual_x_carriage_mode == DXC_FULL_CONTROL_MODE)
        {
          current_position[X_AXIS] = inactive_extruder_x_pos;
          inactive_extruder_x_pos = destination[X_AXIS];
        }
        else if (dual_x_carriage_mode == DXC_DUPLICATION_MODE)
        {
          active_extruder_parked = (active_extruder == 0); // this triggers the second extruder to move into the duplication position
          if (active_extruder == 0 || active_extruder_parked)
            current_position[X_AXIS] = inactive_extruder_x_pos;
          else
            current_position[X_AXIS] = destination[X_AXIS] + duplicate_extruder_x_offset;
          inactive_extruder_x_pos = destination[X_AXIS];
          extruder_duplication_enabled = false;
        }
        else
        {
          // record raised toolhead position for use by unpark
          memcpy(raised_parked_position, current_position, sizeof(raised_parked_position));
          raised_parked_position[Z_AXIS] += TOOLCHANGE_UNPARK_ZLIFT;
          active_extruder_parked = true;
          delayed_move_time = 0;
        }
      #else
        // Offset extruder (only by XY)
        int i;
        for(i = 0; i < 2; i++) {
           current_position[i] = current_position[i] -
                                 extruder_offset[i][active_extruder] +
                                 extruder_offset[i][tmp_extruder];
        }
        // Set the new active extruder and position
        active_extruder = tmp_extruder;
      #endif //else DUAL_X_CARRIAGE
#ifdef DELTA 

  calculate_delta(current_position); // change cartesian kinematic  to  delta kinematic;
   //sent position to plan_set_position();
  plan_set_position(delta[X_AXIS], delta[Y_AXIS], delta[Z_AXIS],current_position[E_AXIS]);
            
#else
        plan_set_position(current_position[X_AXIS], current_position[Y_AXIS], current_position[Z_AXIS], current_position[E_AXIS]);

#endif
        // Move to the old position if 'F' was in the parameters
        if(make_move && Stopped == false) {
           prepare_move();
        }
      }

#ifdef EXT_SOLENOID
      st_synchronize();
      disable_all_solenoids();
      enable_solenoid_on_active_extruder();
#endif //EXT_SOLENOID

      #endif
      SERIAL_ECHO_START;
      SERIAL_ECHO(MSG_ACTIVE_EXTRUDER);
      SERIAL_PROTOCOLLN((int)active_extruder);
    }
  }

  else
  {
    SERIAL_ECHO_START;
    SERIAL_ECHOPGM(MSG_UNKNOWN_COMMAND);
    SERIAL_ECHO(cmdbuffer[bufindr]);
    SERIAL_ECHOLNPGM("\"");
  }

  ClearToSend();
}

void FlushSerialRequestResend()
{
  //char cmdbuffer[bufindr][100]="Resend:";
  MYSERIAL.flush();
  SERIAL_PROTOCOLPGM(MSG_RESEND);
  SERIAL_PROTOCOLLN(gcode_LastN + 1);
  ClearToSend();
}

void ClearToSend()
{
  previous_millis_cmd = millis();
  #ifdef SDSUPPORT
  if(fromsd[bufindr])
    return;
  #endif //SDSUPPORT
  SERIAL_PROTOCOLLNPGM(MSG_OK);
}

void get_coordinates()
{
  bool seen[4]={false,false,false,false};
  for(int8_t i=0; i < NUM_AXIS; i++) {
    if(code_seen(axis_codes[i]))
    {
      destination[i] = (float)code_value() + (axis_relative_modes[i] || relative_mode)*current_position[i];
      seen[i]=true;
    }
    else destination[i] = current_position[i]; //Are these else lines really needed?
  }
  if(code_seen('F')) {
    next_feedrate = code_value();
    if(next_feedrate > 0.0) feedrate = next_feedrate;
  }
}

void get_arc_coordinates()
{
#ifdef SF_ARC_FIX
   bool relative_mode_backup = relative_mode;
   relative_mode = true;
#endif
   get_coordinates();
#ifdef SF_ARC_FIX
   relative_mode=relative_mode_backup;
#endif

   if(code_seen('I')) {
     offset[0] = code_value();
   }
   else {
     offset[0] = 0.0;
   }
   if(code_seen('J')) {
     offset[1] = code_value();
   }
   else {
     offset[1] = 0.0;
   }
}

void clamp_to_software_endstops(float target[3])
{
  if (min_software_endstops) {
    if (target[X_AXIS] < min_pos[X_AXIS]) target[X_AXIS] = min_pos[X_AXIS];
    if (target[Y_AXIS] < min_pos[Y_AXIS]) target[Y_AXIS] = min_pos[Y_AXIS];
    
    float negative_z_offset = 0;
    #ifdef ENABLE_AUTO_BED_LEVELING
      if (Z_PROBE_OFFSET_FROM_EXTRUDER < 0) negative_z_offset = negative_z_offset + Z_PROBE_OFFSET_FROM_EXTRUDER;
      if (add_homing[Z_AXIS] < 0) negative_z_offset = negative_z_offset + add_homing[Z_AXIS];
    #endif
    
    if (target[Z_AXIS] < min_pos[Z_AXIS]+negative_z_offset) target[Z_AXIS] = min_pos[Z_AXIS]+negative_z_offset;
  }

  if (max_software_endstops) {
    if (target[X_AXIS] > max_pos[X_AXIS]) target[X_AXIS] = max_pos[X_AXIS];
    if (target[Y_AXIS] > max_pos[Y_AXIS]) target[Y_AXIS] = max_pos[Y_AXIS];
    if (target[Z_AXIS] > max_pos[Z_AXIS]) target[Z_AXIS] = max_pos[Z_AXIS];
  }
}

#ifdef DELTA
void recalc_delta_settings(float radius, float diagonal_rod)
{
	 delta_tower1_x= -SIN_60*radius; // front left tower
	 delta_tower1_y= -COS_60*radius;	   
	 delta_tower2_x=  SIN_60*radius; // front right tower
	 delta_tower2_y= -COS_60*radius;	   
	 delta_tower3_x= 0.0;                  // back middle tower
	 delta_tower3_y= radius;
	 delta_diagonal_rod_2= sq(diagonal_rod);
}

void calculate_delta(float cartesian[3])
{
  delta[X_AXIS] = sqrt(delta_diagonal_rod_2
                       - sq(delta_tower1_x-cartesian[X_AXIS])
                       - sq(delta_tower1_y-cartesian[Y_AXIS])
                       ) + cartesian[Z_AXIS];
  delta[Y_AXIS] = sqrt(delta_diagonal_rod_2
                       - sq(delta_tower2_x-cartesian[X_AXIS])
                       - sq(delta_tower2_y-cartesian[Y_AXIS])
                       ) + cartesian[Z_AXIS];
  delta[Z_AXIS] = sqrt(delta_diagonal_rod_2
                       - sq(delta_tower3_x-cartesian[X_AXIS])
                       - sq(delta_tower3_y-cartesian[Y_AXIS])
                       ) + cartesian[Z_AXIS];
  /*
  SERIAL_ECHOPGM("cartesian x="); SERIAL_ECHO(cartesian[X_AXIS]);
  SERIAL_ECHOPGM(" y="); SERIAL_ECHO(cartesian[Y_AXIS]);
  SERIAL_ECHOPGM(" z="); SERIAL_ECHOLN(cartesian[Z_AXIS]);

  SERIAL_ECHOPGM("delta x="); SERIAL_ECHO(delta[X_AXIS]);
  SERIAL_ECHOPGM(" y="); SERIAL_ECHO(delta[Y_AXIS]);
  SERIAL_ECHOPGM(" z="); SERIAL_ECHOLN(delta[Z_AXIS]);
  */
}
#endif

void prepare_move()
{
  clamp_to_software_endstops(destination);
  previous_millis_cmd = millis();
  
  #ifdef SCARA //for now same as delta-code

float difference[NUM_AXIS];
for (int8_t i=0; i < NUM_AXIS; i++) {
	difference[i] = destination[i] - current_position[i];
}

float cartesian_mm = sqrt(	sq(difference[X_AXIS]) +
							sq(difference[Y_AXIS]) +
							sq(difference[Z_AXIS]));
if (cartesian_mm < 0.000001) { cartesian_mm = abs(difference[E_AXIS]); }
if (cartesian_mm < 0.000001) { return; }
float seconds = 6000 * cartesian_mm / feedrate / feedmultiply;
int steps = max(1, int(scara_segments_per_second * seconds));
 //SERIAL_ECHOPGM("mm="); SERIAL_ECHO(cartesian_mm);
 //SERIAL_ECHOPGM(" seconds="); SERIAL_ECHO(seconds);
 //SERIAL_ECHOPGM(" steps="); SERIAL_ECHOLN(steps);
for (int s = 1; s <= steps; s++) {
	float fraction = float(s) / float(steps);
	for(int8_t i=0; i < NUM_AXIS; i++) {
		destination[i] = current_position[i] + difference[i] * fraction;
	}

	
	calculate_delta(destination);
         //SERIAL_ECHOPGM("destination[X_AXIS]="); SERIAL_ECHOLN(destination[X_AXIS]);
         //SERIAL_ECHOPGM("destination[Y_AXIS]="); SERIAL_ECHOLN(destination[Y_AXIS]);
         //SERIAL_ECHOPGM("destination[Z_AXIS]="); SERIAL_ECHOLN(destination[Z_AXIS]);
         //SERIAL_ECHOPGM("delta[X_AXIS]="); SERIAL_ECHOLN(delta[X_AXIS]);
         //SERIAL_ECHOPGM("delta[Y_AXIS]="); SERIAL_ECHOLN(delta[Y_AXIS]);
         //SERIAL_ECHOPGM("delta[Z_AXIS]="); SERIAL_ECHOLN(delta[Z_AXIS]);
         
	plan_buffer_line(delta[X_AXIS], delta[Y_AXIS], delta[Z_AXIS],
	destination[E_AXIS], feedrate*feedmultiply/60/100.0,
	active_extruder);
}
#endif // SCARA
  
#ifdef DELTA
  float difference[NUM_AXIS];
  for (int8_t i=0; i < NUM_AXIS; i++) {
    difference[i] = destination[i] - current_position[i];
  }
  float cartesian_mm = sqrt(sq(difference[X_AXIS]) +
                            sq(difference[Y_AXIS]) +
                            sq(difference[Z_AXIS]));
  if (cartesian_mm < 0.000001) { cartesian_mm = abs(difference[E_AXIS]); }
  if (cartesian_mm < 0.000001) { return; }
  float seconds = 6000 * cartesian_mm / feedrate / feedmultiply;
  int steps = max(1, int(delta_segments_per_second * seconds));
  // SERIAL_ECHOPGM("mm="); SERIAL_ECHO(cartesian_mm);
  // SERIAL_ECHOPGM(" seconds="); SERIAL_ECHO(seconds);
  // SERIAL_ECHOPGM(" steps="); SERIAL_ECHOLN(steps);
  for (int s = 1; s <= steps; s++) {
    float fraction = float(s) / float(steps);
    for(int8_t i=0; i < NUM_AXIS; i++) {
      destination[i] = current_position[i] + difference[i] * fraction;
    }
    calculate_delta(destination);
    plan_buffer_line(delta[X_AXIS], delta[Y_AXIS], delta[Z_AXIS],
                     destination[E_AXIS], feedrate*feedmultiply/60/100.0,
                     active_extruder);
  }
  
#endif // DELTA

#ifdef DUAL_X_CARRIAGE
  if (active_extruder_parked)
  {
    if (dual_x_carriage_mode == DXC_DUPLICATION_MODE && active_extruder == 0)
    {
      // move duplicate extruder into correct duplication position.
      plan_set_position(inactive_extruder_x_pos, current_position[Y_AXIS], current_position[Z_AXIS], current_position[E_AXIS]);
      plan_buffer_line(current_position[X_AXIS] + duplicate_extruder_x_offset, current_position[Y_AXIS], current_position[Z_AXIS],
          current_position[E_AXIS], max_feedrate[X_AXIS], 1);
      plan_set_position(current_position[X_AXIS], current_position[Y_AXIS], current_position[Z_AXIS], current_position[E_AXIS]);
      st_synchronize();
      extruder_duplication_enabled = true;
      active_extruder_parked = false;
    }
    else if (dual_x_carriage_mode == DXC_AUTO_PARK_MODE) // handle unparking of head
    {
      if (current_position[E_AXIS] == destination[E_AXIS])
      {
        // this is a travel move - skit it but keep track of current position (so that it can later
        // be used as start of first non-travel move)
        if (delayed_move_time != 0xFFFFFFFFUL)
        {
          memcpy(current_position, destination, sizeof(current_position));
          if (destination[Z_AXIS] > raised_parked_position[Z_AXIS])
            raised_parked_position[Z_AXIS] = destination[Z_AXIS];
          delayed_move_time = millis();
          return;
        }
      }
      delayed_move_time = 0;
      // unpark extruder: 1) raise, 2) move into starting XY position, 3) lower
      plan_buffer_line(raised_parked_position[X_AXIS], raised_parked_position[Y_AXIS], raised_parked_position[Z_AXIS],    current_position[E_AXIS], max_feedrate[Z_AXIS], active_extruder);
      plan_buffer_line(current_position[X_AXIS], current_position[Y_AXIS], raised_parked_position[Z_AXIS],
          current_position[E_AXIS], min(max_feedrate[X_AXIS],max_feedrate[Y_AXIS]), active_extruder);
      plan_buffer_line(current_position[X_AXIS], current_position[Y_AXIS], current_position[Z_AXIS],
          current_position[E_AXIS], max_feedrate[Z_AXIS], active_extruder);
      active_extruder_parked = false;
    }
  }
#endif //DUAL_X_CARRIAGE

#if ! (defined DELTA || defined SCARA)
  // Do not use feedmultiply for E or Z only moves
  if( (current_position[X_AXIS] == destination [X_AXIS]) && (current_position[Y_AXIS] == destination [Y_AXIS])) {
      plan_buffer_line(destination[X_AXIS], destination[Y_AXIS], destination[Z_AXIS], destination[E_AXIS], feedrate/60, active_extruder);
  }
  else {
    plan_buffer_line(destination[X_AXIS], destination[Y_AXIS], destination[Z_AXIS], destination[E_AXIS], feedrate*feedmultiply/60/100.0, active_extruder);
  }
#endif // !(DELTA || SCARA)

  for(int8_t i=0; i < NUM_AXIS; i++) {
    current_position[i] = destination[i];
  }
}

void prepare_arc_move(char isclockwise) {
  float r = hypot(offset[X_AXIS], offset[Y_AXIS]); // Compute arc radius for mc_arc

  // Trace the arc
  mc_arc(current_position, destination, offset, X_AXIS, Y_AXIS, Z_AXIS, feedrate*feedmultiply/60/100.0, r, isclockwise, active_extruder);

  // As far as the parser is concerned, the position is now == target. In reality the
  // motion control system might still be processing the action and the real tool position
  // in any intermediate location.
  for(int8_t i=0; i < NUM_AXIS; i++) {
    current_position[i] = destination[i];
  }
  previous_millis_cmd = millis();
}

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

#if defined(FAN_PIN)
  #if CONTROLLERFAN_PIN == FAN_PIN
    #error "You cannot set CONTROLLERFAN_PIN equal to FAN_PIN"
  #endif
#endif

unsigned long lastMotor = 0; //Save the time for when a motor was turned on last
unsigned long lastMotorCheck = 0;

void controllerFan()
{
  if ((millis() - lastMotorCheck) >= 2500) //Not a time critical function, so we only check every 2500ms
  {
    lastMotorCheck = millis();

    if(!READ(X_ENABLE_PIN) || !READ(Y_ENABLE_PIN) || !READ(Z_ENABLE_PIN) || (soft_pwm_bed > 0)
    #if EXTRUDERS > 2
       || !READ(E2_ENABLE_PIN)
    #endif
    #if EXTRUDER > 1
      #if defined(X2_ENABLE_PIN) && X2_ENABLE_PIN > -1
       || !READ(X2_ENABLE_PIN)
      #endif
       || !READ(E1_ENABLE_PIN)
    #endif
       || !READ(E0_ENABLE_PIN)) //If any of the drivers are enabled...
    {
      lastMotor = millis(); //... set time to NOW so the fan will turn on
    }

    if ((millis() - lastMotor) >= (CONTROLLERFAN_SECS*1000UL) || lastMotor == 0) //If the last time any driver was enabled, is longer since than CONTROLLERSEC...
    {
        digitalWrite(CONTROLLERFAN_PIN, 0);
        analogWrite(CONTROLLERFAN_PIN, 0);
    }
    else
    {
        // allows digital or PWM fan output to be used (see M42 handling)
        digitalWrite(CONTROLLERFAN_PIN, CONTROLLERFAN_SPEED);
        analogWrite(CONTROLLERFAN_PIN, CONTROLLERFAN_SPEED);
    }
  }
}
#endif

#ifdef SCARA
void calculate_SCARA_forward_Transform(float f_scara[3])
{
  // Perform forward kinematics, and place results in delta[3]
  // The maths and first version has been done by QHARLEY . Integrated into masterbranch 06/2014 and slightly restructured by Joachim Cerny in June 2014
  
  float x_sin, x_cos, y_sin, y_cos;
  
    //SERIAL_ECHOPGM("f_delta x="); SERIAL_ECHO(f_scara[X_AXIS]);
    //SERIAL_ECHOPGM(" y="); SERIAL_ECHO(f_scara[Y_AXIS]);
  
    x_sin = sin(f_scara[X_AXIS]/SCARA_RAD2DEG) * Linkage_1;
    x_cos = cos(f_scara[X_AXIS]/SCARA_RAD2DEG) * Linkage_1;
    y_sin = sin(f_scara[Y_AXIS]/SCARA_RAD2DEG) * Linkage_2;
    y_cos = cos(f_scara[Y_AXIS]/SCARA_RAD2DEG) * Linkage_2;
   
  //  SERIAL_ECHOPGM(" x_sin="); SERIAL_ECHO(x_sin);
  //  SERIAL_ECHOPGM(" x_cos="); SERIAL_ECHO(x_cos);
  //  SERIAL_ECHOPGM(" y_sin="); SERIAL_ECHO(y_sin);
  //  SERIAL_ECHOPGM(" y_cos="); SERIAL_ECHOLN(y_cos);
  
    delta[X_AXIS] = x_cos + y_cos + SCARA_offset_x;  //theta
    delta[Y_AXIS] = x_sin + y_sin + SCARA_offset_y;  //theta+phi
	
    //SERIAL_ECHOPGM(" delta[X_AXIS]="); SERIAL_ECHO(delta[X_AXIS]);
    //SERIAL_ECHOPGM(" delta[Y_AXIS]="); SERIAL_ECHOLN(delta[Y_AXIS]);
}  

void calculate_delta(float cartesian[3]){
  //reverse kinematics.
  // Perform reversed kinematics, and place results in delta[3]
  // The maths and first version has been done by QHARLEY . Integrated into masterbranch 06/2014 and slightly restructured by Joachim Cerny in June 2014
  
  float SCARA_pos[2];
  static float SCARA_C2, SCARA_S2, SCARA_K1, SCARA_K2, SCARA_theta, SCARA_psi; 
  
  SCARA_pos[X_AXIS] = cartesian[X_AXIS] * axis_scaling[X_AXIS] - SCARA_offset_x;  //Translate SCARA to standard X Y
  SCARA_pos[Y_AXIS] = cartesian[Y_AXIS] * axis_scaling[Y_AXIS] - SCARA_offset_y;  // With scaling factor.
  
  #if (Linkage_1 == Linkage_2)
    SCARA_C2 = ( ( sq(SCARA_pos[X_AXIS]) + sq(SCARA_pos[Y_AXIS]) ) / (2 * (float)L1_2) ) - 1;
  #else
    SCARA_C2 =   ( sq(SCARA_pos[X_AXIS]) + sq(SCARA_pos[Y_AXIS]) - (float)L1_2 - (float)L2_2 ) / 45000; 
  #endif
  
  SCARA_S2 = sqrt( 1 - sq(SCARA_C2) );
  
  SCARA_K1 = Linkage_1 + Linkage_2 * SCARA_C2;
  SCARA_K2 = Linkage_2 * SCARA_S2;
  
  SCARA_theta = ( atan2(SCARA_pos[X_AXIS],SCARA_pos[Y_AXIS])-atan2(SCARA_K1, SCARA_K2) ) * -1;
  SCARA_psi   =   atan2(SCARA_S2,SCARA_C2);
  
  delta[X_AXIS] = SCARA_theta * SCARA_RAD2DEG;  // Multiply by 180/Pi  -  theta is support arm angle
  delta[Y_AXIS] = (SCARA_theta + SCARA_psi) * SCARA_RAD2DEG;  //       -  equal to sub arm angle (inverted motor)
  delta[Z_AXIS] = cartesian[Z_AXIS];
  
  /*
  SERIAL_ECHOPGM("cartesian x="); SERIAL_ECHO(cartesian[X_AXIS]);
  SERIAL_ECHOPGM(" y="); SERIAL_ECHO(cartesian[Y_AXIS]);
  SERIAL_ECHOPGM(" z="); SERIAL_ECHOLN(cartesian[Z_AXIS]);
  
  SERIAL_ECHOPGM("scara x="); SERIAL_ECHO(SCARA_pos[X_AXIS]);
  SERIAL_ECHOPGM(" y="); SERIAL_ECHOLN(SCARA_pos[Y_AXIS]);
  
  SERIAL_ECHOPGM("delta x="); SERIAL_ECHO(delta[X_AXIS]);
  SERIAL_ECHOPGM(" y="); SERIAL_ECHO(delta[Y_AXIS]);
  SERIAL_ECHOPGM(" z="); SERIAL_ECHOLN(delta[Z_AXIS]);
  
  SERIAL_ECHOPGM("C2="); SERIAL_ECHO(SCARA_C2);
  SERIAL_ECHOPGM(" S2="); SERIAL_ECHO(SCARA_S2);
  SERIAL_ECHOPGM(" Theta="); SERIAL_ECHO(SCARA_theta);
  SERIAL_ECHOPGM(" Psi="); SERIAL_ECHOLN(SCARA_psi);
  SERIAL_ECHOLN(" ");*/
}

#endif

#ifdef TEMP_STAT_LEDS
static bool blue_led = false;
static bool red_led = false;
static uint32_t stat_update = 0;

void handle_status_leds(void) {
  float max_temp = 0.0;
  if(millis() > stat_update) {
    stat_update += 500; // Update every 0.5s
    for (int8_t cur_extruder = 0; cur_extruder < EXTRUDERS; ++cur_extruder) {
       max_temp = max(max_temp, degHotend(cur_extruder));
       max_temp = max(max_temp, degTargetHotend(cur_extruder));
    }
    #if defined(TEMP_BED_PIN) && TEMP_BED_PIN > -1
      max_temp = max(max_temp, degTargetBed());
      max_temp = max(max_temp, degBed());
    #endif
    if((max_temp > 55.0) && (red_led == false)) {
      digitalWrite(STAT_LED_RED, 1);
      digitalWrite(STAT_LED_BLUE, 0);
      red_led = true;
      blue_led = false;
    }
    if((max_temp < 54.0) && (blue_led == false)) {
      digitalWrite(STAT_LED_RED, 0);
      digitalWrite(STAT_LED_BLUE, 1);
      red_led = false;
      blue_led = true;
    }
  }
}
#endif

void manage_inactivity(bool ignore_stepper_queue/*=false*/) //default argument set in Marlin.h
{
	
#if defined(KILL_PIN) && KILL_PIN > -1
	static int killCount = 0;   // make the inactivity button a bit less responsive
   const int KILL_DELAY = 10000;
#endif

#if defined(HOME_PIN) && HOME_PIN > -1
   static int homeDebounceCount = 0;   // poor man's debouncing count
   const int HOME_DEBOUNCE_DELAY = 10000;
#endif
   
	
  if(buflen < (BUFSIZE-1))
    get_command();

  if( (millis() - previous_millis_cmd) >  max_inactive_time )
    if(max_inactive_time)
      kill();
  if(stepper_inactive_time)  {
    if( (millis() - previous_millis_cmd) >  stepper_inactive_time )
    {
      if(blocks_queued() == false && ignore_stepper_queue == false) {
        disable_x();
        disable_y();
        disable_z();
        disable_e0();
        disable_e1();
        disable_e2();
      }
    }
  }
  
  #ifdef CHDK //Check if pin should be set to LOW after M240 set it to HIGH
    if (chdkActive && (millis() - chdkHigh > CHDK_DELAY))
    {
      chdkActive = false;
      WRITE(CHDK, LOW);
    }
  #endif
  
  #if defined(KILL_PIN) && KILL_PIN > -1
    
    // Check if the kill button was pressed and wait just in case it was an accidental
    // key kill key press
    // -------------------------------------------------------------------------------
    if( 0 == READ(KILL_PIN) )
    {
       killCount++;
    }
    else if (killCount > 0)
    {
       killCount--;
    }
    // Exceeded threshold and we can confirm that it was not accidental
    // KILL the machine
    // ----------------------------------------------------------------
    if ( killCount >= KILL_DELAY)
    {
       kill();
    }
  #endif

#if defined(HOME_PIN) && HOME_PIN > -1
    // Check to see if we have to home, use poor man's debouncer
    // ---------------------------------------------------------
    if ( 0 == READ(HOME_PIN) )
    {
       if (homeDebounceCount == 0)
       {
          enquecommands_P((PSTR("G28")));
          homeDebounceCount++;
          LCD_ALERTMESSAGEPGM(MSG_AUTO_HOME);
       }
       else if (homeDebounceCount < HOME_DEBOUNCE_DELAY)
       {
          homeDebounceCount++;
       }
       else
       {
          homeDebounceCount = 0;
       }
    }
#endif
    
  #if defined(CONTROLLERFAN_PIN) && CONTROLLERFAN_PIN > -1
    controllerFan(); //Check if fan should be turned on to cool stepper drivers down
  #endif
  #ifdef EXTRUDER_RUNOUT_PREVENT
    if( (millis() - previous_millis_cmd) >  EXTRUDER_RUNOUT_SECONDS*1000 )
    if(degHotend(active_extruder)>EXTRUDER_RUNOUT_MINTEMP)
    {
     bool oldstatus=READ(E0_ENABLE_PIN);
     enable_e0();
     float oldepos=current_position[E_AXIS];
     float oldedes=destination[E_AXIS];
     plan_buffer_line(destination[X_AXIS], destination[Y_AXIS], destination[Z_AXIS],
                      destination[E_AXIS]+EXTRUDER_RUNOUT_EXTRUDE*EXTRUDER_RUNOUT_ESTEPS/axis_steps_per_unit[E_AXIS],
                      EXTRUDER_RUNOUT_SPEED/60.*EXTRUDER_RUNOUT_ESTEPS/axis_steps_per_unit[E_AXIS], active_extruder);
     current_position[E_AXIS]=oldepos;
     destination[E_AXIS]=oldedes;
     plan_set_e_position(oldepos);
     previous_millis_cmd=millis();
     st_synchronize();
     WRITE(E0_ENABLE_PIN,oldstatus);
    }
  #endif
  #if defined(DUAL_X_CARRIAGE)
    // handle delayed move timeout
    if (delayed_move_time != 0 && (millis() - delayed_move_time) > 1000 && Stopped == false)
    {
      // travel moves have been received so enact them
      delayed_move_time = 0xFFFFFFFFUL; // force moves to be done
      memcpy(destination,current_position,sizeof(destination));
      prepare_move();
    }
  #endif
  #ifdef TEMP_STAT_LEDS
      handle_status_leds();
  #endif
  check_axes_activity();
}

void kill()
{
  cli(); // Stop interrupts
  disable_heater();

  disable_x();
  disable_y();
  disable_z();
  disable_e0();
  disable_e1();
  disable_e2();

#if defined(PS_ON_PIN) && PS_ON_PIN > -1
  pinMode(PS_ON_PIN,INPUT);
#endif
  SERIAL_ERROR_START;
  SERIAL_ERRORLNPGM(MSG_ERR_KILLED);
  LCD_ALERTMESSAGEPGM(MSG_KILLED);
  
  // FMC small patch to update the LCD before ending
  sei();   // enable interrupts
  for ( int i=5; i--; lcd_update())
  {
     delay(200);	
  }
  cli();   // disable interrupts
  suicide();
  while(1) { /* Intentionally left empty */ } // Wait for reset
}

void Stop()
{
  disable_heater();
  if(Stopped == false) {
    Stopped = true;
    Stopped_gcode_LastN = gcode_LastN; // Save last g_code for restart
    SERIAL_ERROR_START;
    SERIAL_ERRORLNPGM(MSG_ERR_STOPPED);
    LCD_MESSAGEPGM(MSG_STOPPED);
  }
}

bool IsStopped() { return Stopped; };

#ifdef FAST_PWM_FAN
void setPwmFrequency(uint8_t pin, int val)
{
  val &= 0x07;
  switch(digitalPinToTimer(pin))
  {

    #if defined(TCCR0A)
    case TIMER0A:
    case TIMER0B:
//         TCCR0B &= ~(_BV(CS00) | _BV(CS01) | _BV(CS02));
//         TCCR0B |= val;
         break;
    #endif

    #if defined(TCCR1A)
    case TIMER1A:
    case TIMER1B:
//         TCCR1B &= ~(_BV(CS10) | _BV(CS11) | _BV(CS12));
//         TCCR1B |= val;
         break;
    #endif

    #if defined(TCCR2)
    case TIMER2:
    case TIMER2:
         TCCR2 &= ~(_BV(CS10) | _BV(CS11) | _BV(CS12));
         TCCR2 |= val;
         break;
    #endif

    #if defined(TCCR2A)
    case TIMER2A:
    case TIMER2B:
         TCCR2B &= ~(_BV(CS20) | _BV(CS21) | _BV(CS22));
         TCCR2B |= val;
         break;
    #endif

    #if defined(TCCR3A)
    case TIMER3A:
    case TIMER3B:
    case TIMER3C:
         TCCR3B &= ~(_BV(CS30) | _BV(CS31) | _BV(CS32));
         TCCR3B |= val;
         break;
    #endif

    #if defined(TCCR4A)
    case TIMER4A:
    case TIMER4B:
    case TIMER4C:
         TCCR4B &= ~(_BV(CS40) | _BV(CS41) | _BV(CS42));
         TCCR4B |= val;
         break;
   #endif

    #if defined(TCCR5A)
    case TIMER5A:
    case TIMER5B:
    case TIMER5C:
         TCCR5B &= ~(_BV(CS50) | _BV(CS51) | _BV(CS52));
         TCCR5B |= val;
         break;
   #endif

  }
}
#endif //FAST_PWM_FAN

bool setTargetedHotend(int code){
  tmp_extruder = active_extruder;
  if(code_seen('T')) {
    tmp_extruder = code_value();
    if(tmp_extruder >= EXTRUDERS) {
      SERIAL_ECHO_START;
      switch(code){
        case 104:
          SERIAL_ECHO(MSG_M104_INVALID_EXTRUDER);
          break;
        case 105:
          SERIAL_ECHO(MSG_M105_INVALID_EXTRUDER);
          break;
        case 109:
          SERIAL_ECHO(MSG_M109_INVALID_EXTRUDER);
          break;
        case 218:
          SERIAL_ECHO(MSG_M218_INVALID_EXTRUDER);
          break;
        case 221:
          SERIAL_ECHO(MSG_M221_INVALID_EXTRUDER);
          break;
      }
      SERIAL_ECHOLN(tmp_extruder);
      return true;
    }
  }
  return false;
}

float calculate_volumetric_multiplier(float diameter) {
  if (!volumetric_enabled || diameter == 0) return 1.0;
  float d2 = diameter * 0.5;
  return 1.0 / (M_PI * d2 * d2);
}

void calculate_volumetric_multipliers() {
  for (int i=0; i<EXTRUDERS; i++)
    volumetric_multiplier[i] = calculate_volumetric_multiplier(filament_size[i]);
}

#ifdef EXT_SOLENOID

void enable_solenoid(uint8_t num) {
  switch(num) {
    case 0:
      OUT_WRITE(SOL0_PIN, HIGH);
      break;
      #if defined(SOL1_PIN) && SOL1_PIN > -1
        case 1:
          OUT_WRITE(SOL1_PIN, HIGH);
          break;
      #endif
      #if defined(SOL2_PIN) && SOL2_PIN > -1
        case 2:
          OUT_WRITE(SOL2_PIN, HIGH);
          break;
      #endif
      #if defined(SOL3_PIN) && SOL3_PIN > -1
        case 3:
          OUT_WRITE(SOL3_PIN, HIGH);
          break;
      #endif
    default:
      SERIAL_ECHO_START;
      SERIAL_ECHOLNPGM(MSG_INVALID_SOLENOID);
      break;
  }
}

void enable_solenoid_on_active_extruder() { enable_solenoid(active_extruder); }

void disable_all_solenoids() {
  OUT_WRITE(SOL0_PIN, LOW);
  OUT_WRITE(SOL1_PIN, LOW);
  OUT_WRITE(SOL2_PIN, LOW);
  OUT_WRITE(SOL3_PIN, LOW);
}

#endif //EXT_SOLENOID