PrusaFirmware/Firmware/stepper.cpp

/*
  stepper.c - stepper motor driver: executes motion plans using stepper motors
  Part of Grbl

  Copyright (c) 2009-2011 Simen Svale Skogsrud

  Grbl 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.

  Grbl 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 Grbl.  If not, see <http://www.gnu.org/licenses/>.
*/

/* The timer calculations of this module informed by the 'RepRap cartesian firmware' by Zack Smith
   and Philipp Tiefenbacher. */

#include "Marlin.h"
#include "stepper.h"
#include "planner.h"
#include "temperature.h"
#include "ultralcd.h"
#include "language.h"
#include "cardreader.h"
#include "speed_lookuptable.h"
#if defined(DIGIPOTSS_PIN) && DIGIPOTSS_PIN > -1
#include <SPI.h>
#endif
#ifdef TMC2130
#include "tmc2130.h"
#endif //TMC2130

#ifdef FILAMENT_SENSOR
#include "fsensor.h"
int fsensor_counter = 0; //counter for e-steps
#endif //FILAMENT_SENSOR

#include "mmu.h"

#ifdef DEBUG_STACK_MONITOR
uint16_t SP_min = 0x21FF;
#endif //DEBUG_STACK_MONITOR

//===========================================================================
//=============================public variables  ============================
//===========================================================================
block_t *current_block;  // A pointer to the block currently being traced
bool x_min_endstop = false;
bool x_max_endstop = false;
bool y_min_endstop = false;
bool y_max_endstop = false;
bool z_min_endstop = false;
bool z_max_endstop = false;
//===========================================================================
//=============================private variables ============================
//===========================================================================
//static makes it inpossible to be called from outside of this file by extern.!

// Variables used by The Stepper Driver Interrupt
static unsigned char out_bits;        // The next stepping-bits to be output
static dda_isteps_t
               counter_x,       // Counter variables for the bresenham line tracer
               counter_y,
               counter_z,
               counter_e;
volatile dda_usteps_t step_events_completed; // The number of step events executed in the current block
static int32_t  acceleration_time, deceleration_time;
//static unsigned long accelerate_until, decelerate_after, acceleration_rate, initial_rate, final_rate, nominal_rate;
static uint16_t acc_step_rate; // needed for deccelaration start point
static uint8_t  step_loops;
static uint16_t OCR1A_nominal;
static uint8_t  step_loops_nominal;

volatile long endstops_trigsteps[3]={0,0,0};
volatile long endstops_stepsTotal,endstops_stepsDone;
static volatile bool endstop_x_hit=false;
static volatile bool endstop_y_hit=false;
static volatile bool endstop_z_hit=false;
#ifdef ABORT_ON_ENDSTOP_HIT_FEATURE_ENABLED
bool abort_on_endstop_hit = false;
#endif
#ifdef MOTOR_CURRENT_PWM_XY_PIN
  int motor_current_setting[3] = DEFAULT_PWM_MOTOR_CURRENT;
  int motor_current_setting_silent[3] = DEFAULT_PWM_MOTOR_CURRENT;
  int motor_current_setting_loud[3] = DEFAULT_PWM_MOTOR_CURRENT_LOUD;
#endif

static bool old_x_min_endstop=false;
static bool old_x_max_endstop=false;
static bool old_y_min_endstop=false;
static bool old_y_max_endstop=false;
static bool old_z_min_endstop=false;
static bool old_z_max_endstop=false;

static bool check_endstops = true;

static bool check_z_endstop = false;
static bool z_endstop_invert = false;

volatile long count_position[NUM_AXIS] = { 0, 0, 0, 0};
volatile signed char count_direction[NUM_AXIS] = { 1, 1, 1, 1};

#ifdef LIN_ADVANCE

  static uint16_t nextMainISR = 0;
  static uint16_t eISR_Rate;

  // Extrusion steps to be executed by the stepper.
  // If set to non zero, the timer ISR routine will tick the Linear Advance extruder ticks first.
  // If e_steps is zero, then the timer ISR routine will perform the usual DDA step.
  static volatile int16_t e_steps = 0;
  // How many extruder steps shall be ticked at a single ISR invocation?
  static uint8_t          estep_loops;
  // The current speed of the extruder, scaled by the linear advance constant, so it has the same measure
  // as current_adv_steps.
  static int              current_estep_rate;
  // The current pretension of filament expressed in extruder micro steps.
  static int              current_adv_steps;

  #define _NEXT_ISR(T)    nextMainISR = T
#else
  #define _NEXT_ISR(T)    OCR1A = T
#endif

#ifdef DEBUG_STEPPER_TIMER_MISSED
extern bool stepper_timer_overflow_state;
extern uint16_t stepper_timer_overflow_last;
#endif /* DEBUG_STEPPER_TIMER_MISSED */

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

#ifndef _NO_ASM

// intRes = intIn1 * intIn2 >> 16
// uses:
// r26 to store 0
// r27 to store the byte 1 of the 24 bit result
#define MultiU16X8toH16(intRes, charIn1, intIn2) \
asm volatile ( \
"clr r26 \n\t" \
"mul %A1, %B2 \n\t" \
"movw %A0, r0 \n\t" \
"mul %A1, %A2 \n\t" \
"add %A0, r1 \n\t" \
"adc %B0, r26 \n\t" \
"lsr r0 \n\t" \
"adc %A0, r26 \n\t" \
"adc %B0, r26 \n\t" \
"clr r1 \n\t" \
: \
"=&r" (intRes) \
: \
"d" (charIn1), \
"d" (intIn2) \
: \
"r26" \
)

// intRes = longIn1 * longIn2 >> 24
// uses:
// r26 to store 0
// r27 to store the byte 1 of the 48bit result
#define MultiU24X24toH16(intRes, longIn1, longIn2) \
asm volatile ( \
"clr r26 \n\t" \
"mul %A1, %B2 \n\t" \
"mov r27, r1 \n\t" \
"mul %B1, %C2 \n\t" \
"movw %A0, r0 \n\t" \
"mul %C1, %C2 \n\t" \
"add %B0, r0 \n\t" \
"mul %C1, %B2 \n\t" \
"add %A0, r0 \n\t" \
"adc %B0, r1 \n\t" \
"mul %A1, %C2 \n\t" \
"add r27, r0 \n\t" \
"adc %A0, r1 \n\t" \
"adc %B0, r26 \n\t" \
"mul %B1, %B2 \n\t" \
"add r27, r0 \n\t" \
"adc %A0, r1 \n\t" \
"adc %B0, r26 \n\t" \
"mul %C1, %A2 \n\t" \
"add r27, r0 \n\t" \
"adc %A0, r1 \n\t" \
"adc %B0, r26 \n\t" \
"mul %B1, %A2 \n\t" \
"add r27, r1 \n\t" \
"adc %A0, r26 \n\t" \
"adc %B0, r26 \n\t" \
"lsr r27 \n\t" \
"adc %A0, r26 \n\t" \
"adc %B0, r26 \n\t" \
"clr r1 \n\t" \
: \
"=&r" (intRes) \
: \
"d" (longIn1), \
"d" (longIn2) \
: \
"r26" , "r27" \
)

#else //_NO_ASM

void MultiU16X8toH16(unsigned short& intRes, unsigned char& charIn1, unsigned short& intIn2)
{
}

void MultiU24X24toH16(uint16_t& intRes, int32_t& longIn1, long& longIn2)
{
}

#endif //_NO_ASM

// Some useful constants

void checkHitEndstops()
{
 if( endstop_x_hit || endstop_y_hit || endstop_z_hit) {
   SERIAL_ECHO_START;
   SERIAL_ECHORPGM(_T(MSG_ENDSTOPS_HIT));
   if(endstop_x_hit) {
     SERIAL_ECHOPAIR(" X:",(float)endstops_trigsteps[X_AXIS]/axis_steps_per_unit[X_AXIS]);
//     LCD_MESSAGERPGM(CAT2(_T(MSG_ENDSTOPS_HIT), PSTR("X")));
   }
   if(endstop_y_hit) {
     SERIAL_ECHOPAIR(" Y:",(float)endstops_trigsteps[Y_AXIS]/axis_steps_per_unit[Y_AXIS]);
//     LCD_MESSAGERPGM(CAT2(_T(MSG_ENDSTOPS_HIT), PSTR("Y")));
   }
   if(endstop_z_hit) {
     SERIAL_ECHOPAIR(" Z:",(float)endstops_trigsteps[Z_AXIS]/axis_steps_per_unit[Z_AXIS]);
//     LCD_MESSAGERPGM(CAT2(_T(MSG_ENDSTOPS_HIT),PSTR("Z")));
   }
   SERIAL_ECHOLN("");
   endstop_x_hit=false;
   endstop_y_hit=false;
   endstop_z_hit=false;
#if defined(ABORT_ON_ENDSTOP_HIT_FEATURE_ENABLED) && defined(SDSUPPORT)
   if (abort_on_endstop_hit)
   {
     card.sdprinting = false;
     card.closefile();
     quickStop();
     setTargetHotend0(0);
     setTargetHotend1(0);
     setTargetHotend2(0);
   }
#endif
 }
}

bool endstops_hit_on_purpose()
{
  bool hit = endstop_x_hit || endstop_y_hit || endstop_z_hit;
  endstop_x_hit=false;
  endstop_y_hit=false;
  endstop_z_hit=false;
  return hit;
}

bool endstop_z_hit_on_purpose()
{
  bool hit = endstop_z_hit;
  endstop_z_hit=false;
  return hit;
}

bool enable_endstops(bool check)
{
  bool old = check_endstops;
  check_endstops = check;
  return old;
}

bool enable_z_endstop(bool check)
{
	bool old = check_z_endstop;
	check_z_endstop = check;
	endstop_z_hit = false;
	return old;
}

void invert_z_endstop(bool endstop_invert)
{
  z_endstop_invert = endstop_invert;
}

//         __________________________
//        /|                        |\     _________________         ^
//       / |                        | \   /|               |\        |
//      /  |                        |  \ / |               | \       s
//     /   |                        |   |  |               |  \      p
//    /    |                        |   |  |               |   \     e
//   +-----+------------------------+---+--+---------------+----+    e
//   |               BLOCK 1            |      BLOCK 2          |    d
//
//                           time ----->
//
//  The trapezoid is the shape the speed curve over time. It starts at block->initial_rate, accelerates
//  first block->accelerate_until step_events_completed, then keeps going at constant speed until
//  step_events_completed reaches block->decelerate_after after which it decelerates until the trapezoid generator is reset.
//  The slope of acceleration is calculated with the leib ramp alghorithm.

FORCE_INLINE unsigned short calc_timer(uint16_t step_rate) {
  unsigned short timer;
  if(step_rate > MAX_STEP_FREQUENCY) step_rate = MAX_STEP_FREQUENCY;

  if(step_rate > 20000) { // If steprate > 20kHz >> step 4 times
    step_rate = (step_rate >> 2)&0x3fff;
    step_loops = 4;
  }
  else if(step_rate > 10000) { // If steprate > 10kHz >> step 2 times
    step_rate = (step_rate >> 1)&0x7fff;
    step_loops = 2;
  }
  else {
    step_loops = 1;
  }
//    step_loops = 1;

  if(step_rate < (F_CPU/500000)) step_rate = (F_CPU/500000);
  step_rate -= (F_CPU/500000); // Correct for minimal speed
  if(step_rate >= (8*256)){ // higher step rate
    unsigned short table_address = (unsigned short)&speed_lookuptable_fast[(unsigned char)(step_rate>>8)][0];
    unsigned char tmp_step_rate = (step_rate & 0x00ff);
    unsigned short gain = (unsigned short)pgm_read_word_near(table_address+2);
    MultiU16X8toH16(timer, tmp_step_rate, gain);
    timer = (unsigned short)pgm_read_word_near(table_address) - timer;
  }
  else { // lower step rates
    unsigned short table_address = (unsigned short)&speed_lookuptable_slow[0][0];
    table_address += ((step_rate)>>1) & 0xfffc;
    timer = (unsigned short)pgm_read_word_near(table_address);
    timer -= (((unsigned short)pgm_read_word_near(table_address+2) * (unsigned char)(step_rate & 0x0007))>>3);
  }
  if(timer < 100) { timer = 100; MYSERIAL.print(_i("Steprate too high: ")); MYSERIAL.println(step_rate); }//(20kHz this should never happen)////MSG_STEPPER_TOO_HIGH c=0 r=0
  return timer;
}

// "The Stepper Driver Interrupt" - This timer interrupt is the workhorse.
// It pops blocks from the block_buffer and executes them by pulsing the stepper pins appropriately.
ISR(TIMER1_COMPA_vect) {
#ifdef DEBUG_STACK_MONITOR
	uint16_t sp = SPL + 256 * SPH;
	if (sp < SP_min) SP_min = sp;
#endif //DEBUG_STACK_MONITOR

#ifdef LIN_ADVANCE
  // If there are any e_steps planned, tick them.
  bool run_main_isr = false;
  if (e_steps) {
    //WRITE_NC(LOGIC_ANALYZER_CH7, true);
    for (uint8_t i = estep_loops; e_steps && i --;) {
        WRITE_NC(E0_STEP_PIN, !INVERT_E_STEP_PIN);
        -- e_steps;
        WRITE_NC(E0_STEP_PIN, INVERT_E_STEP_PIN);
    }
    if (e_steps) {
      // Plan another Linear Advance tick.
      OCR1A = eISR_Rate;
      nextMainISR -= eISR_Rate;
    } else if (! (nextMainISR & 0x8000) || nextMainISR < 16) {
      // The timer did not overflow and it is big enough, so it makes sense to plan it.
      OCR1A = nextMainISR;
    } else {
      // The timer has overflown, or it is too small. Run the main ISR just after the Linear Advance routine
      // in the current interrupt tick.
      run_main_isr = true;
      //FIXME pick the serial line.
    }
    //WRITE_NC(LOGIC_ANALYZER_CH7, false);
  } else
    run_main_isr = true;

  if (run_main_isr)
#endif
    isr();

  // Don't run the ISR faster than possible
  // Is there a 8us time left before the next interrupt triggers?
  if (OCR1A < TCNT1 + 16) {
#ifdef DEBUG_STEPPER_TIMER_MISSED
    // Verify whether the next planned timer interrupt has not been missed already.  
    // This debugging test takes < 1.125us
    // This skews the profiling slightly as the fastest stepper timer
    // interrupt repeats at a 100us rate (10kHz).
    if (OCR1A + 40 < TCNT1) {
      // The interrupt was delayed by more than 20us (which is 1/5th of the 10kHz ISR repeat rate).
      // Give a warning.
      stepper_timer_overflow_state = true;
      stepper_timer_overflow_last = TCNT1 - OCR1A;
      // Beep, the beeper will be cleared at the stepper_timer_overflow() called from the main thread.
      WRITE(BEEPER, HIGH);
    }
#endif
    // Fix the next interrupt to be executed after 8us from now.
    OCR1A = TCNT1 + 16; 
  }
}

uint8_t last_dir_bits = 0;

#ifdef BACKLASH_X
uint8_t st_backlash_x = 0;
#endif //BACKLASH_X
#ifdef BACKLASH_Y
uint8_t st_backlash_y = 0;
#endif //BACKLASH_Y

FORCE_INLINE void stepper_next_block()
{
  // Anything in the buffer?
  //WRITE_NC(LOGIC_ANALYZER_CH2, true);
  current_block = plan_get_current_block();
  if (current_block != NULL) {
#ifdef BACKLASH_X
	if (current_block->steps_x.wide)
	{ //X-axis movement
		if ((current_block->direction_bits ^ last_dir_bits) & 1)
		{
			printf_P(PSTR("BL %d\n"), (current_block->direction_bits & 1)?st_backlash_x:-st_backlash_x);
			if (current_block->direction_bits & 1)
				WRITE_NC(X_DIR_PIN, INVERT_X_DIR);
			else
				WRITE_NC(X_DIR_PIN, !INVERT_X_DIR);
			_delay_us(100);
			for (uint8_t i = 0; i < st_backlash_x; i++)
			{
				WRITE_NC(X_STEP_PIN, !INVERT_X_STEP_PIN);
				_delay_us(100);
				WRITE_NC(X_STEP_PIN, INVERT_X_STEP_PIN);
				_delay_us(900);
			}
		}
		last_dir_bits &= ~1;
		last_dir_bits |= current_block->direction_bits & 1;
	}
#endif
#ifdef BACKLASH_Y
	if (current_block->steps_y.wide)
	{ //Y-axis movement
		if ((current_block->direction_bits ^ last_dir_bits) & 2)
		{
			printf_P(PSTR("BL %d\n"), (current_block->direction_bits & 2)?st_backlash_y:-st_backlash_y);
			if (current_block->direction_bits & 2)
				WRITE_NC(Y_DIR_PIN, INVERT_Y_DIR);
			else
				WRITE_NC(Y_DIR_PIN, !INVERT_Y_DIR);
			_delay_us(100);
			for (uint8_t i = 0; i < st_backlash_y; i++)
			{
				WRITE_NC(Y_STEP_PIN, !INVERT_Y_STEP_PIN);
				_delay_us(100);
				WRITE_NC(Y_STEP_PIN, INVERT_Y_STEP_PIN);
				_delay_us(900);
			}
		}
		last_dir_bits &= ~2;
		last_dir_bits |= current_block->direction_bits & 2;
	}
#endif

#ifdef FILAMENT_SENSOR
	if (mmu_enabled == false)
	{
		fsensor_counter = 0;
		fsensor_st_block_begin(current_block);
	}
#endif //FILAMENT_SENSOR
    // The busy flag is set by the plan_get_current_block() call.
    // current_block->busy = true;
    // Initializes the trapezoid generator from the current block. Called whenever a new
    // block begins.
    deceleration_time = 0;
    // Set the nominal step loops to zero to indicate, that the timer value is not known yet.
    // That means, delay the initialization of nominal step rate and step loops until the steady
    // state is reached.
    step_loops_nominal = 0;
    acc_step_rate = uint16_t(current_block->initial_rate);
    acceleration_time = calc_timer(acc_step_rate);
#ifdef LIN_ADVANCE
    current_estep_rate = ((unsigned long)acc_step_rate * current_block->abs_adv_steps_multiplier8) >> 17;
#endif /* LIN_ADVANCE */

    if (current_block->flag & BLOCK_FLAG_DDA_LOWRES) {
      counter_x.lo = -(current_block->step_event_count.lo >> 1);
      counter_y.lo = counter_x.lo;
      counter_z.lo = counter_x.lo;
      counter_e.lo = counter_x.lo;
    } else {
      counter_x.wide = -(current_block->step_event_count.wide >> 1);
      counter_y.wide = counter_x.wide;
      counter_z.wide = counter_x.wide;
      counter_e.wide = counter_x.wide;
    }
    step_events_completed.wide = 0;
    // Set directions.
    out_bits = current_block->direction_bits;
    // Set the direction bits (X_AXIS=A_AXIS and Y_AXIS=B_AXIS for COREXY)
    if((out_bits & (1<<X_AXIS))!=0){
      WRITE_NC(X_DIR_PIN, INVERT_X_DIR);
      count_direction[X_AXIS]=-1;
    } else {
      WRITE_NC(X_DIR_PIN, !INVERT_X_DIR);
      count_direction[X_AXIS]=1;
    }
    if((out_bits & (1<<Y_AXIS))!=0){
      WRITE_NC(Y_DIR_PIN, INVERT_Y_DIR);
      count_direction[Y_AXIS]=-1;
    } else {
      WRITE_NC(Y_DIR_PIN, !INVERT_Y_DIR);
      count_direction[Y_AXIS]=1;
    }
    if ((out_bits & (1<<Z_AXIS)) != 0) {   // -direction
      WRITE_NC(Z_DIR_PIN,INVERT_Z_DIR);
      count_direction[Z_AXIS]=-1;
    } else { // +direction
      WRITE_NC(Z_DIR_PIN,!INVERT_Z_DIR);
      count_direction[Z_AXIS]=1;
    }
    if ((out_bits & (1 << E_AXIS)) != 0) { // -direction
#ifndef LIN_ADVANCE
      WRITE(E0_DIR_PIN, 
  #ifdef SNMM
        (mmu_extruder == 0 || mmu_extruder == 2) ? !INVERT_E0_DIR :
  #endif // SNMM
        INVERT_E0_DIR);
#endif /* LIN_ADVANCE */
      count_direction[E_AXIS] = -1;
    } else { // +direction
#ifndef LIN_ADVANCE
      WRITE(E0_DIR_PIN,
  #ifdef SNMM
        (mmu_extruder == 0 || mmu_extruder == 2) ? INVERT_E0_DIR :
  #endif // SNMM
        !INVERT_E0_DIR);
#endif /* LIN_ADVANCE */
      count_direction[E_AXIS] = 1;
    }
  }
  else {
    OCR1A = 2000; // 1kHz.
  }
  //WRITE_NC(LOGIC_ANALYZER_CH2, false);
}

// Check limit switches.
FORCE_INLINE void stepper_check_endstops()
{
  if(check_endstops) 
  {
    #ifndef COREXY
    if ((out_bits & (1<<X_AXIS)) != 0) // stepping along -X axis
    #else
    if ((((out_bits & (1<<X_AXIS)) != 0)&&(out_bits & (1<<Y_AXIS)) != 0)) //-X occurs for -A and -B
    #endif
    {
      #if ( (defined(X_MIN_PIN) && (X_MIN_PIN > -1)) || defined(TMC2130_SG_HOMING) ) && !defined(DEBUG_DISABLE_XMINLIMIT)
      #ifdef TMC2130_SG_HOMING
        // Stall guard homing turned on
        x_min_endstop = (READ(X_TMC2130_DIAG) != 0);
      #else
        // Normal homing
        x_min_endstop = (READ(X_MIN_PIN) != X_MIN_ENDSTOP_INVERTING);
      #endif
        if(x_min_endstop && old_x_min_endstop && (current_block->steps_x.wide > 0)) {
          endstops_trigsteps[X_AXIS] = count_position[X_AXIS];
          endstop_x_hit=true;
          step_events_completed.wide = current_block->step_event_count.wide;
        }
        old_x_min_endstop = x_min_endstop;
      #endif
    } else { // +direction
      #if ( (defined(X_MAX_PIN) && (X_MAX_PIN > -1)) || defined(TMC2130_SG_HOMING) ) && !defined(DEBUG_DISABLE_XMAXLIMIT)          
        #ifdef TMC2130_SG_HOMING
        // Stall guard homing turned on
            x_max_endstop = (READ(X_TMC2130_DIAG) != 0);
        #else
        // Normal homing
        x_max_endstop = (READ(X_MAX_PIN) != X_MAX_ENDSTOP_INVERTING);
        #endif
        if(x_max_endstop && old_x_max_endstop && (current_block->steps_x.wide > 0)){
          endstops_trigsteps[X_AXIS] = count_position[X_AXIS];
          endstop_x_hit=true;
          step_events_completed.wide = current_block->step_event_count.wide;
        }
        old_x_max_endstop = x_max_endstop;
      #endif
    }

    #ifndef COREXY
    if ((out_bits & (1<<Y_AXIS)) != 0) // -direction
    #else
    if ((((out_bits & (1<<X_AXIS)) != 0)&&(out_bits & (1<<Y_AXIS)) == 0)) // -Y occurs for -A and +B
    #endif
    {        
      #if ( (defined(Y_MIN_PIN) && (Y_MIN_PIN > -1)) || defined(TMC2130_SG_HOMING) ) && !defined(DEBUG_DISABLE_YMINLIMIT)          
      #ifdef TMC2130_SG_HOMING
      // Stall guard homing turned on
          y_min_endstop = (READ(Y_TMC2130_DIAG) != 0);
      #else
      // Normal homing
      y_min_endstop = (READ(Y_MIN_PIN) != Y_MIN_ENDSTOP_INVERTING);
      #endif
        if(y_min_endstop && old_y_min_endstop && (current_block->steps_y.wide > 0)) {
          endstops_trigsteps[Y_AXIS] = count_position[Y_AXIS];
          endstop_y_hit=true;
          step_events_completed.wide = current_block->step_event_count.wide;
        }
        old_y_min_endstop = y_min_endstop;
      #endif
    } else { // +direction
      #if ( (defined(Y_MAX_PIN) && (Y_MAX_PIN > -1)) || defined(TMC2130_SG_HOMING) ) && !defined(DEBUG_DISABLE_YMAXLIMIT)                
        #ifdef TMC2130_SG_HOMING
        // Stall guard homing turned on
            y_max_endstop = (READ(Y_TMC2130_DIAG) != 0);
        #else
        // Normal homing
        y_max_endstop = (READ(Y_MAX_PIN) != Y_MAX_ENDSTOP_INVERTING);
        #endif
        if(y_max_endstop && old_y_max_endstop && (current_block->steps_y.wide > 0)){
          endstops_trigsteps[Y_AXIS] = count_position[Y_AXIS];
          endstop_y_hit=true;
          step_events_completed.wide = current_block->step_event_count.wide;
        }
        old_y_max_endstop = y_max_endstop;
      #endif
    }

    if ((out_bits & (1<<Z_AXIS)) != 0) // -direction
    {
      #if defined(Z_MIN_PIN) && (Z_MIN_PIN > -1) && !defined(DEBUG_DISABLE_ZMINLIMIT)
      if (! check_z_endstop) {
        #ifdef TMC2130_SG_HOMING
          // Stall guard homing turned on
#ifdef TMC2130_STEALTH_Z
		  if ((tmc2130_mode == TMC2130_MODE_SILENT) && !(tmc2130_sg_homing_axes_mask & 0x04))
	          z_min_endstop = (READ(Z_MIN_PIN) != Z_MIN_ENDSTOP_INVERTING);
		  else
#endif //TMC2130_STEALTH_Z
	          z_min_endstop = (READ(Z_MIN_PIN) != Z_MIN_ENDSTOP_INVERTING) || (READ(Z_TMC2130_DIAG) != 0);
        #else
          z_min_endstop = (READ(Z_MIN_PIN) != Z_MIN_ENDSTOP_INVERTING);
        #endif //TMC2130_SG_HOMING
        if(z_min_endstop && old_z_min_endstop && (current_block->steps_z.wide > 0)) {
          endstops_trigsteps[Z_AXIS] = count_position[Z_AXIS];
          endstop_z_hit=true;
          step_events_completed.wide = current_block->step_event_count.wide;
        }
        old_z_min_endstop = z_min_endstop;
      }
      #endif
    } else { // +direction
      #if defined(Z_MAX_PIN) && (Z_MAX_PIN > -1) && !defined(DEBUG_DISABLE_ZMAXLIMIT)
        #ifdef TMC2130_SG_HOMING
        // Stall guard homing turned on
#ifdef TMC2130_STEALTH_Z
		  if ((tmc2130_mode == TMC2130_MODE_SILENT) && !(tmc2130_sg_homing_axes_mask & 0x04))
	          z_max_endstop = false;
		  else
#endif //TMC2130_STEALTH_Z
        z_max_endstop = (READ(Z_TMC2130_DIAG) != 0);
        #else
        z_max_endstop = (READ(Z_MAX_PIN) != Z_MAX_ENDSTOP_INVERTING);
        #endif //TMC2130_SG_HOMING
        if(z_max_endstop && old_z_max_endstop && (current_block->steps_z.wide > 0)) {
          endstops_trigsteps[Z_AXIS] = count_position[Z_AXIS];
          endstop_z_hit=true;
          step_events_completed.wide = current_block->step_event_count.wide;
        }
        old_z_max_endstop = z_max_endstop;
      #endif
    }
  }

  // Supporting stopping on a trigger of the Z-stop induction sensor, not only for the Z-minus movements.
  #if defined(Z_MIN_PIN) && (Z_MIN_PIN > -1) && !defined(DEBUG_DISABLE_ZMINLIMIT)
  if (check_z_endstop) {
      // Check the Z min end-stop no matter what.
      // Good for searching for the center of an induction target.
      #ifdef TMC2130_SG_HOMING
      // Stall guard homing turned on
#ifdef TMC2130_STEALTH_Z
		  if ((tmc2130_mode == TMC2130_MODE_SILENT) && !(tmc2130_sg_homing_axes_mask & 0x04))
	          z_min_endstop = (READ(Z_MIN_PIN) != Z_MIN_ENDSTOP_INVERTING);
		  else
#endif //TMC2130_STEALTH_Z
       z_min_endstop = (READ(Z_MIN_PIN) != Z_MIN_ENDSTOP_INVERTING) || (READ(Z_TMC2130_DIAG) != 0);
      #else
        z_min_endstop = (READ(Z_MIN_PIN) != Z_MIN_ENDSTOP_INVERTING);
      #endif //TMC2130_SG_HOMING
      if(z_min_endstop && old_z_min_endstop) {
        endstops_trigsteps[Z_AXIS] = count_position[Z_AXIS];
        endstop_z_hit=true;
        step_events_completed.wide = current_block->step_event_count.wide;
      }
      old_z_min_endstop = z_min_endstop;
  }
  #endif
}


FORCE_INLINE void stepper_tick_lowres()
{
  for (uint8_t i=0; i < step_loops; ++ i) { // Take multiple steps per interrupt (For high speed moves)
    MSerial.checkRx(); // Check for serial chars.
    // Step in X axis
    counter_x.lo += current_block->steps_x.lo;
    if (counter_x.lo > 0) {
      WRITE_NC(X_STEP_PIN, !INVERT_X_STEP_PIN);
#ifdef DEBUG_XSTEP_DUP_PIN
      WRITE_NC(DEBUG_XSTEP_DUP_PIN,!INVERT_X_STEP_PIN);
#endif //DEBUG_XSTEP_DUP_PIN
      counter_x.lo -= current_block->step_event_count.lo;
      count_position[X_AXIS]+=count_direction[X_AXIS];
      WRITE_NC(X_STEP_PIN, INVERT_X_STEP_PIN);
#ifdef DEBUG_XSTEP_DUP_PIN
      WRITE_NC(DEBUG_XSTEP_DUP_PIN,INVERT_X_STEP_PIN);
#endif //DEBUG_XSTEP_DUP_PIN
    }
    // Step in Y axis
    counter_y.lo += current_block->steps_y.lo;
    if (counter_y.lo > 0) {
      WRITE_NC(Y_STEP_PIN, !INVERT_Y_STEP_PIN);
#ifdef DEBUG_YSTEP_DUP_PIN
      WRITE_NC(DEBUG_YSTEP_DUP_PIN,!INVERT_Y_STEP_PIN);
#endif //DEBUG_YSTEP_DUP_PIN
      counter_y.lo -= current_block->step_event_count.lo;
      count_position[Y_AXIS]+=count_direction[Y_AXIS];
      WRITE_NC(Y_STEP_PIN, INVERT_Y_STEP_PIN);
#ifdef DEBUG_YSTEP_DUP_PIN
      WRITE_NC(DEBUG_YSTEP_DUP_PIN,INVERT_Y_STEP_PIN);
#endif //DEBUG_YSTEP_DUP_PIN    
    }
    // Step in Z axis
    counter_z.lo += current_block->steps_z.lo;
    if (counter_z.lo > 0) {
      WRITE_NC(Z_STEP_PIN, !INVERT_Z_STEP_PIN);
      counter_z.lo -= current_block->step_event_count.lo;
      count_position[Z_AXIS]+=count_direction[Z_AXIS];
      WRITE_NC(Z_STEP_PIN, INVERT_Z_STEP_PIN);
    }
    // Step in E axis
    counter_e.lo += current_block->steps_e.lo;
    if (counter_e.lo > 0) {
#ifndef LIN_ADVANCE
      WRITE(E0_STEP_PIN, !INVERT_E_STEP_PIN);
#endif /* LIN_ADVANCE */
      counter_e.lo -= current_block->step_event_count.lo;
      count_position[E_AXIS] += count_direction[E_AXIS];
#ifdef LIN_ADVANCE
      ++ e_steps;
#else
  #ifdef FILAMENT_SENSOR
      ++ fsensor_counter;
  #endif //FILAMENT_SENSOR
      WRITE(E0_STEP_PIN, INVERT_E_STEP_PIN);
#endif
    }
    if(++ step_events_completed.lo >= current_block->step_event_count.lo)
      break;
  }
}

FORCE_INLINE void stepper_tick_highres()
{
  for (uint8_t i=0; i < step_loops; ++ i) { // Take multiple steps per interrupt (For high speed moves)
    MSerial.checkRx(); // Check for serial chars.
    // Step in X axis
    counter_x.wide += current_block->steps_x.wide;
    if (counter_x.wide > 0) {
      WRITE_NC(X_STEP_PIN, !INVERT_X_STEP_PIN);
#ifdef DEBUG_XSTEP_DUP_PIN
      WRITE_NC(DEBUG_XSTEP_DUP_PIN,!INVERT_X_STEP_PIN);
#endif //DEBUG_XSTEP_DUP_PIN
      counter_x.wide -= current_block->step_event_count.wide;
      count_position[X_AXIS]+=count_direction[X_AXIS];   
      WRITE_NC(X_STEP_PIN, INVERT_X_STEP_PIN);
#ifdef DEBUG_XSTEP_DUP_PIN
      WRITE_NC(DEBUG_XSTEP_DUP_PIN,INVERT_X_STEP_PIN);
#endif //DEBUG_XSTEP_DUP_PIN
    }
    // Step in Y axis
    counter_y.wide += current_block->steps_y.wide;
    if (counter_y.wide > 0) {
      WRITE_NC(Y_STEP_PIN, !INVERT_Y_STEP_PIN);
#ifdef DEBUG_YSTEP_DUP_PIN
      WRITE_NC(DEBUG_YSTEP_DUP_PIN,!INVERT_Y_STEP_PIN);
#endif //DEBUG_YSTEP_DUP_PIN
      counter_y.wide -= current_block->step_event_count.wide;
      count_position[Y_AXIS]+=count_direction[Y_AXIS];
      WRITE_NC(Y_STEP_PIN, INVERT_Y_STEP_PIN);
#ifdef DEBUG_YSTEP_DUP_PIN
      WRITE_NC(DEBUG_YSTEP_DUP_PIN,INVERT_Y_STEP_PIN);
#endif //DEBUG_YSTEP_DUP_PIN    
    }
    // Step in Z axis
    counter_z.wide += current_block->steps_z.wide;
    if (counter_z.wide > 0) {
      WRITE_NC(Z_STEP_PIN, !INVERT_Z_STEP_PIN);
      counter_z.wide -= current_block->step_event_count.wide;
      count_position[Z_AXIS]+=count_direction[Z_AXIS];
      WRITE_NC(Z_STEP_PIN, INVERT_Z_STEP_PIN);
    }
    // Step in E axis
    counter_e.wide += current_block->steps_e.wide;
    if (counter_e.wide > 0) {
#ifndef LIN_ADVANCE
      WRITE(E0_STEP_PIN, !INVERT_E_STEP_PIN);
#endif /* LIN_ADVANCE */
      counter_e.wide -= current_block->step_event_count.wide;
      count_position[E_AXIS]+=count_direction[E_AXIS];
#ifdef LIN_ADVANCE
      ++ e_steps;
#else
  #ifdef FILAMENT_SENSOR
      ++ fsensor_counter;
  #endif //FILAMENT_SENSOR
      WRITE(E0_STEP_PIN, INVERT_E_STEP_PIN);
#endif
    }
    if(++ step_events_completed.wide >= current_block->step_event_count.wide)
      break;
  }
}

// 50us delay
#define LIN_ADV_FIRST_TICK_DELAY 100

FORCE_INLINE void isr() {
  //WRITE_NC(LOGIC_ANALYZER_CH0, true);

	//if (UVLO) uvlo();
  // If there is no current block, attempt to pop one from the buffer
  if (current_block == NULL)
    stepper_next_block();

  if (current_block != NULL) 
  {
    stepper_check_endstops();
#ifdef LIN_ADVANCE
      e_steps = 0;
#endif /* LIN_ADVANCE */
    if (current_block->flag & BLOCK_FLAG_DDA_LOWRES)
      stepper_tick_lowres();
    else
      stepper_tick_highres();

#ifdef LIN_ADVANCE
      if (out_bits&(1<<E_AXIS))
        // Move in negative direction.
        e_steps = - e_steps;
      if (current_block->use_advance_lead) {
        //int esteps_inc = 0;
        //esteps_inc = current_estep_rate - current_adv_steps;
        //e_steps += esteps_inc;
        e_steps += current_estep_rate - current_adv_steps;
#if 0
        if (abs(esteps_inc) > 4) {
          LOGIC_ANALYZER_SERIAL_TX_WRITE(esteps_inc);
          if (esteps_inc < -511 || esteps_inc > 511)
            LOGIC_ANALYZER_SERIAL_TX_WRITE(esteps_inc >> 9);
        }
#endif
        current_adv_steps = current_estep_rate;
      }
      // If we have esteps to execute, step some of them now.
      if (e_steps) {
        //WRITE_NC(LOGIC_ANALYZER_CH7, true);
        // Set the step direction.
        {
          bool neg = e_steps < 0;
          bool dir =
        #ifdef SNMM
            (neg == (mmu_extruder & 1))
        #else
            neg
        #endif
            ? INVERT_E0_DIR : !INVERT_E0_DIR; //If we have SNMM, reverse every second extruder.
          WRITE_NC(E0_DIR_PIN, dir);
          if (neg)
            // Flip the e_steps counter to be always positive.
            e_steps = - e_steps;
        }
        // Tick min(step_loops, abs(e_steps)).
        estep_loops = (e_steps & 0x0ff00) ? 4 : e_steps;
        if (step_loops < estep_loops)
          estep_loops = step_loops;
    #ifdef FILAMENT_SENSOR
		if (mmu_enabled == false)
		{
			fsensor_counter += estep_loops;
		}
    #endif //FILAMENT_SENSOR
        do {
          WRITE_NC(E0_STEP_PIN, !INVERT_E_STEP_PIN);
          -- e_steps;
          WRITE_NC(E0_STEP_PIN, INVERT_E_STEP_PIN);
        } while (-- estep_loops != 0);
        //WRITE_NC(LOGIC_ANALYZER_CH7, false);
        MSerial.checkRx(); // Check for serial chars.
      }
#endif

    // Calculare new timer value
    // 13.38-14.63us for steady state,
    // 25.12us for acceleration / deceleration.
    {
      //WRITE_NC(LOGIC_ANALYZER_CH1, true);
      if (step_events_completed.wide <= (unsigned long int)current_block->accelerate_until) {
        // v = t * a   ->   acc_step_rate = acceleration_time * current_block->acceleration_rate
        MultiU24X24toH16(acc_step_rate, acceleration_time, current_block->acceleration_rate);
        acc_step_rate += uint16_t(current_block->initial_rate);
        // upper limit
        if(acc_step_rate > uint16_t(current_block->nominal_rate))
          acc_step_rate = current_block->nominal_rate;
        // step_rate to timer interval
        uint16_t timer = calc_timer(acc_step_rate);
        _NEXT_ISR(timer);
        acceleration_time += timer;
  #ifdef LIN_ADVANCE
        if (current_block->use_advance_lead)
          // int32_t = (uint16_t * uint32_t) >> 17
          current_estep_rate = ((uint32_t)acc_step_rate * current_block->abs_adv_steps_multiplier8) >> 17;
  #endif
      }
      else if (step_events_completed.wide > (unsigned long int)current_block->decelerate_after) {
        uint16_t step_rate;
        MultiU24X24toH16(step_rate, deceleration_time, current_block->acceleration_rate);
        step_rate = acc_step_rate - step_rate; // Decelerate from aceleration end point.
        if ((step_rate & 0x8000) || step_rate < uint16_t(current_block->final_rate)) {
          // Result is negative or too small.
          step_rate = uint16_t(current_block->final_rate);
        }
        // Step_rate to timer interval.
        uint16_t timer = calc_timer(step_rate);
        _NEXT_ISR(timer);
        deceleration_time += timer;
  #ifdef LIN_ADVANCE
        if (current_block->use_advance_lead)
          current_estep_rate = ((uint32_t)step_rate * current_block->abs_adv_steps_multiplier8) >> 17;
  #endif
      }
      else {
        if (! step_loops_nominal) {
          // Calculation of the steady state timer rate has been delayed to the 1st tick of the steady state to lower
          // the initial interrupt blocking.
          OCR1A_nominal = calc_timer(uint16_t(current_block->nominal_rate));
          step_loops_nominal = step_loops;
  #ifdef LIN_ADVANCE
          if (current_block->use_advance_lead)
            current_estep_rate = (current_block->nominal_rate * current_block->abs_adv_steps_multiplier8) >> 17;
  #endif
        }
        _NEXT_ISR(OCR1A_nominal);
      }
      //WRITE_NC(LOGIC_ANALYZER_CH1, false);
    }

#ifdef LIN_ADVANCE
    if (e_steps && current_block->use_advance_lead) {
      //WRITE_NC(LOGIC_ANALYZER_CH7, true);
      MSerial.checkRx(); // Check for serial chars.
      // Some of the E steps were not ticked yet. Plan additional interrupts.
      uint16_t now = TCNT1;
      // Plan the first linear advance interrupt after 50us from now.
      uint16_t to_go = nextMainISR - now - LIN_ADV_FIRST_TICK_DELAY;
      eISR_Rate = 0;
      if ((to_go & 0x8000) == 0) {
        // The to_go number is not negative.
        // Count the number of 7812,5 ticks, that fit into to_go 2MHz ticks.
        uint8_t ticks = to_go >> 8;
        if (ticks == 1) {
          // Avoid running the following loop for a very short interval.
          estep_loops = 255;
          eISR_Rate = 1;
        } else if ((e_steps & 0x0ff00) == 0) {
          // e_steps <= 0x0ff
          if (uint8_t(e_steps) <= ticks) {
            // Spread the e_steps along the whole go_to interval.
            eISR_Rate = to_go / uint8_t(e_steps);
            estep_loops = 1;
          } else if (ticks != 0) {
            // At least one tick fits into the to_go interval. Calculate the e-step grouping.
            uint8_t e = uint8_t(e_steps) >> 1;
            estep_loops = 2;
            while (e > ticks) {
              e >>= 1;
              estep_loops <<= 1;
            }
            // Now the estep_loops contains the number of loops of power of 2, that will be sufficient
            // to squeeze enough of Linear Advance ticks until nextMainISR.
            // Calculate the tick rate.
            eISR_Rate = to_go / ticks;          
          }
        } else {
          // This is an exterme case with too many e_steps inserted by the linear advance.
          // At least one tick fits into the to_go interval. Calculate the e-step grouping.
          estep_loops = 2;
          uint16_t e = e_steps >> 1;
          while (e & 0x0ff00) {
            e >>= 1;
            estep_loops <<= 1;
          }
          while (uint8_t(e) > ticks) {
            e >>= 1;
            estep_loops <<= 1;
          }
          // Now the estep_loops contains the number of loops of power of 2, that will be sufficient
          // to squeeze enough of Linear Advance ticks until nextMainISR.
          // Calculate the tick rate.
          eISR_Rate = to_go / ticks;
        }
      }
      if (eISR_Rate == 0) {
        // There is not enough time to fit even a single additional tick.
        // Tick all the extruder ticks now.
    #ifdef FILAMENT_SENSOR
		  if (mmu_enabled == false) {
			  fsensor_counter += e_steps;
		  }
    #endif //FILAMENT_SENSOR
        MSerial.checkRx(); // Check for serial chars.
        do {
          WRITE_NC(E0_STEP_PIN, !INVERT_E_STEP_PIN);
          -- e_steps;
          WRITE_NC(E0_STEP_PIN, INVERT_E_STEP_PIN);
        } while (e_steps);
        OCR1A = nextMainISR;
      } else {
        // Tick the 1st Linear Advance interrupt after 50us from now.
        nextMainISR -= LIN_ADV_FIRST_TICK_DELAY;
        OCR1A = now + LIN_ADV_FIRST_TICK_DELAY;
      }
      //WRITE_NC(LOGIC_ANALYZER_CH7, false);
    } else
      OCR1A = nextMainISR;
#endif

    // If current block is finished, reset pointer
    if (step_events_completed.wide >= current_block->step_event_count.wide) {
#ifdef FILAMENT_SENSOR
		if (mmu_enabled == false) {
			fsensor_st_block_chunk(current_block, fsensor_counter);
			fsensor_counter = 0;
		}
#endif //FILAMENT_SENSOR

      current_block = NULL;
      plan_discard_current_block();
    }
#ifdef FILAMENT_SENSOR
  	else if ((fsensor_counter >= fsensor_chunk_len) && (mmu_enabled == false))
  	{
      fsensor_st_block_chunk(current_block, fsensor_counter);
  	  fsensor_counter = 0;
  	}
#endif //FILAMENT_SENSOR
  }

#ifdef TMC2130
	tmc2130_st_isr();
#endif //TMC2130

  //WRITE_NC(LOGIC_ANALYZER_CH0, false);
}

#ifdef LIN_ADVANCE

void clear_current_adv_vars() {
  e_steps = 0; //Should be already 0 at an filament change event, but just to be sure..
  current_adv_steps = 0;
}

#endif // LIN_ADVANCE
      
void st_init()
{
#ifdef TMC2130
	tmc2130_init();
#endif //TMC2130

  st_current_init(); //Initialize Digipot Motor Current
  microstep_init(); //Initialize Microstepping Pins

  //Initialize Dir Pins
  #if defined(X_DIR_PIN) && X_DIR_PIN > -1
    SET_OUTPUT(X_DIR_PIN);
  #endif
  #if defined(X2_DIR_PIN) && X2_DIR_PIN > -1
    SET_OUTPUT(X2_DIR_PIN);
  #endif
  #if defined(Y_DIR_PIN) && Y_DIR_PIN > -1
    SET_OUTPUT(Y_DIR_PIN);
		
	#if defined(Y_DUAL_STEPPER_DRIVERS) && defined(Y2_DIR_PIN) && (Y2_DIR_PIN > -1)
	  SET_OUTPUT(Y2_DIR_PIN);
	#endif
  #endif
  #if defined(Z_DIR_PIN) && Z_DIR_PIN > -1
    SET_OUTPUT(Z_DIR_PIN);

    #if defined(Z_DUAL_STEPPER_DRIVERS) && defined(Z2_DIR_PIN) && (Z2_DIR_PIN > -1)
      SET_OUTPUT(Z2_DIR_PIN);
    #endif
  #endif
  #if defined(E0_DIR_PIN) && E0_DIR_PIN > -1
    SET_OUTPUT(E0_DIR_PIN);
  #endif
  #if defined(E1_DIR_PIN) && (E1_DIR_PIN > -1)
    SET_OUTPUT(E1_DIR_PIN);
  #endif
  #if defined(E2_DIR_PIN) && (E2_DIR_PIN > -1)
    SET_OUTPUT(E2_DIR_PIN);
  #endif

  //Initialize Enable Pins - steppers default to disabled.

  #if defined(X_ENABLE_PIN) && X_ENABLE_PIN > -1
    SET_OUTPUT(X_ENABLE_PIN);
    if(!X_ENABLE_ON) WRITE(X_ENABLE_PIN,HIGH);
  #endif
  #if defined(X2_ENABLE_PIN) && X2_ENABLE_PIN > -1
    SET_OUTPUT(X2_ENABLE_PIN);
    if(!X_ENABLE_ON) WRITE(X2_ENABLE_PIN,HIGH);
  #endif
  #if defined(Y_ENABLE_PIN) && Y_ENABLE_PIN > -1
    SET_OUTPUT(Y_ENABLE_PIN);
    if(!Y_ENABLE_ON) WRITE(Y_ENABLE_PIN,HIGH);
	
	#if defined(Y_DUAL_STEPPER_DRIVERS) && defined(Y2_ENABLE_PIN) && (Y2_ENABLE_PIN > -1)
	  SET_OUTPUT(Y2_ENABLE_PIN);
	  if(!Y_ENABLE_ON) WRITE(Y2_ENABLE_PIN,HIGH);
	#endif
  #endif
  #if defined(Z_ENABLE_PIN) && Z_ENABLE_PIN > -1
    SET_OUTPUT(Z_ENABLE_PIN);
    if(!Z_ENABLE_ON) WRITE(Z_ENABLE_PIN,HIGH);

    #if defined(Z_DUAL_STEPPER_DRIVERS) && defined(Z2_ENABLE_PIN) && (Z2_ENABLE_PIN > -1)
      SET_OUTPUT(Z2_ENABLE_PIN);
      if(!Z_ENABLE_ON) WRITE(Z2_ENABLE_PIN,HIGH);
    #endif
  #endif
  #if defined(E0_ENABLE_PIN) && (E0_ENABLE_PIN > -1)
    SET_OUTPUT(E0_ENABLE_PIN);
    if(!E_ENABLE_ON) WRITE(E0_ENABLE_PIN,HIGH);
  #endif
  #if defined(E1_ENABLE_PIN) && (E1_ENABLE_PIN > -1)
    SET_OUTPUT(E1_ENABLE_PIN);
    if(!E_ENABLE_ON) WRITE(E1_ENABLE_PIN,HIGH);
  #endif
  #if defined(E2_ENABLE_PIN) && (E2_ENABLE_PIN > -1)
    SET_OUTPUT(E2_ENABLE_PIN);
    if(!E_ENABLE_ON) WRITE(E2_ENABLE_PIN,HIGH);
  #endif

  //endstops and pullups

  #ifdef TMC2130_SG_HOMING
    SET_INPUT(X_TMC2130_DIAG);
    WRITE(X_TMC2130_DIAG,HIGH);
    
    SET_INPUT(Y_TMC2130_DIAG);
    WRITE(Y_TMC2130_DIAG,HIGH);
    
    SET_INPUT(Z_TMC2130_DIAG);
    WRITE(Z_TMC2130_DIAG,HIGH);

	SET_INPUT(E0_TMC2130_DIAG);
    WRITE(E0_TMC2130_DIAG,HIGH);
    
  #endif
    
  #if defined(X_MIN_PIN) && X_MIN_PIN > -1
    SET_INPUT(X_MIN_PIN);
    #ifdef ENDSTOPPULLUP_XMIN
      WRITE(X_MIN_PIN,HIGH);
    #endif
  #endif

  #if defined(Y_MIN_PIN) && Y_MIN_PIN > -1
    SET_INPUT(Y_MIN_PIN);
    #ifdef ENDSTOPPULLUP_YMIN
      WRITE(Y_MIN_PIN,HIGH);
    #endif
  #endif

  #if defined(Z_MIN_PIN) && Z_MIN_PIN > -1
    SET_INPUT(Z_MIN_PIN);
    #ifdef ENDSTOPPULLUP_ZMIN
      WRITE(Z_MIN_PIN,HIGH);
    #endif
  #endif

  #if defined(X_MAX_PIN) && X_MAX_PIN > -1
    SET_INPUT(X_MAX_PIN);
    #ifdef ENDSTOPPULLUP_XMAX
      WRITE(X_MAX_PIN,HIGH);
    #endif
  #endif

  #if defined(Y_MAX_PIN) && Y_MAX_PIN > -1
    SET_INPUT(Y_MAX_PIN);
    #ifdef ENDSTOPPULLUP_YMAX
      WRITE(Y_MAX_PIN,HIGH);
    #endif
  #endif

  #if defined(Z_MAX_PIN) && Z_MAX_PIN > -1
    SET_INPUT(Z_MAX_PIN);
    #ifdef ENDSTOPPULLUP_ZMAX
      WRITE(Z_MAX_PIN,HIGH);
    #endif
  #endif

  #if (defined(FANCHECK) && defined(TACH_0) && (TACH_0 > -1))
	SET_INPUT(TACH_0);
    #ifdef TACH0PULLUP
	  WRITE(TACH_0, HIGH);
    #endif
  #endif


  //Initialize Step Pins
#if defined(X_STEP_PIN) && (X_STEP_PIN > -1)
    SET_OUTPUT(X_STEP_PIN);
    WRITE(X_STEP_PIN,INVERT_X_STEP_PIN);
#ifdef DEBUG_XSTEP_DUP_PIN
    SET_OUTPUT(DEBUG_XSTEP_DUP_PIN);
    WRITE(DEBUG_XSTEP_DUP_PIN,INVERT_X_STEP_PIN);
#endif //DEBUG_XSTEP_DUP_PIN
    disable_x();
  #endif
  #if defined(X2_STEP_PIN) && (X2_STEP_PIN > -1)
    SET_OUTPUT(X2_STEP_PIN);
    WRITE(X2_STEP_PIN,INVERT_X_STEP_PIN);
    disable_x();
  #endif
  #if defined(Y_STEP_PIN) && (Y_STEP_PIN > -1)
    SET_OUTPUT(Y_STEP_PIN);
    WRITE(Y_STEP_PIN,INVERT_Y_STEP_PIN);
#ifdef DEBUG_YSTEP_DUP_PIN
    SET_OUTPUT(DEBUG_YSTEP_DUP_PIN);
    WRITE(DEBUG_YSTEP_DUP_PIN,INVERT_Y_STEP_PIN);
#endif //DEBUG_YSTEP_DUP_PIN
    #if defined(Y_DUAL_STEPPER_DRIVERS) && defined(Y2_STEP_PIN) && (Y2_STEP_PIN > -1)
      SET_OUTPUT(Y2_STEP_PIN);
      WRITE(Y2_STEP_PIN,INVERT_Y_STEP_PIN);
    #endif
    disable_y();
  #endif
  #if defined(Z_STEP_PIN) && (Z_STEP_PIN > -1)
    SET_OUTPUT(Z_STEP_PIN);
    WRITE(Z_STEP_PIN,INVERT_Z_STEP_PIN);
    #if defined(Z_DUAL_STEPPER_DRIVERS) && defined(Z2_STEP_PIN) && (Z2_STEP_PIN > -1)
      SET_OUTPUT(Z2_STEP_PIN);
      WRITE(Z2_STEP_PIN,INVERT_Z_STEP_PIN);
    #endif
    disable_z();
  #endif
  #if defined(E0_STEP_PIN) && (E0_STEP_PIN > -1)
    SET_OUTPUT(E0_STEP_PIN);
    WRITE(E0_STEP_PIN,INVERT_E_STEP_PIN);
    disable_e0();
  #endif
  #if defined(E1_STEP_PIN) && (E1_STEP_PIN > -1)
    SET_OUTPUT(E1_STEP_PIN);
    WRITE(E1_STEP_PIN,INVERT_E_STEP_PIN);
    disable_e1();
  #endif
  #if defined(E2_STEP_PIN) && (E2_STEP_PIN > -1)
    SET_OUTPUT(E2_STEP_PIN);
    WRITE(E2_STEP_PIN,INVERT_E_STEP_PIN);
    disable_e2();
  #endif

  // waveform generation = 0100 = CTC
  TCCR1B &= ~(1<<WGM13);
  TCCR1B |=  (1<<WGM12);
  TCCR1A &= ~(1<<WGM11);
  TCCR1A &= ~(1<<WGM10);

  // output mode = 00 (disconnected)
  TCCR1A &= ~(3<<COM1A0);
  TCCR1A &= ~(3<<COM1B0);

  // Set the timer pre-scaler
  // Generally we use a divider of 8, resulting in a 2MHz timer
  // frequency on a 16MHz MCU. If you are going to change this, be
  // sure to regenerate speed_lookuptable.h with
  // create_speed_lookuptable.py
  TCCR1B = (TCCR1B & ~(0x07<<CS10)) | (2<<CS10);

  // Plan the first interrupt after 8ms from now.
  OCR1A = 0x4000;
  TCNT1 = 0;
  ENABLE_STEPPER_DRIVER_INTERRUPT();

#ifdef LIN_ADVANCE
    e_steps = 0;
    current_adv_steps = 0;
#endif
    
  enable_endstops(true); // Start with endstops active. After homing they can be disabled
  sei();
}


// Block until all buffered steps are executed
void st_synchronize()
{
	while(blocks_queued())
	{
#ifdef TMC2130
		manage_heater();
		// Vojtech: Don't disable motors inside the planner!
		if (!tmc2130_update_sg())
		{
			manage_inactivity(true);
			lcd_update(0);
		}
#else //TMC2130
		manage_heater();
		// Vojtech: Don't disable motors inside the planner!
		manage_inactivity(true);
		lcd_update(0);
#endif //TMC2130
	}
}

void st_set_position(const long &x, const long &y, const long &z, const long &e)
{
  CRITICAL_SECTION_START;
  // Copy 4x4B.
  // This block locks the interrupts globally for 4.56 us,
  // which corresponds to a maximum repeat frequency of 219.18 kHz.
  // This blocking is safe in the context of a 10kHz stepper driver interrupt
  // or a 115200 Bd serial line receive interrupt, which will not trigger faster than 12kHz.
  count_position[X_AXIS] = x;
  count_position[Y_AXIS] = y;
  count_position[Z_AXIS] = z;
  count_position[E_AXIS] = e;
  CRITICAL_SECTION_END;
}

void st_set_e_position(const long &e)
{
  CRITICAL_SECTION_START;
  count_position[E_AXIS] = e;
  CRITICAL_SECTION_END;
}

long st_get_position(uint8_t axis)
{
  long count_pos;
  CRITICAL_SECTION_START;
  count_pos = count_position[axis];
  CRITICAL_SECTION_END;
  return count_pos;
}

void st_get_position_xy(long &x, long &y)
{
  CRITICAL_SECTION_START;
  x = count_position[X_AXIS];
  y = count_position[Y_AXIS];
  CRITICAL_SECTION_END;
}

float st_get_position_mm(uint8_t axis)
{
  float steper_position_in_steps = st_get_position(axis);
  return steper_position_in_steps / axis_steps_per_unit[axis];
}


void finishAndDisableSteppers()
{
  st_synchronize();
  disable_x();
  disable_y();
  disable_z();
  disable_e0();
  disable_e1();
  disable_e2();
}

void quickStop()
{
  DISABLE_STEPPER_DRIVER_INTERRUPT();
  while (blocks_queued()) plan_discard_current_block(); 
  current_block = NULL;
  st_reset_timer();
  ENABLE_STEPPER_DRIVER_INTERRUPT();
}

#ifdef BABYSTEPPING


void babystep(const uint8_t axis,const bool direction)
{
  //MUST ONLY BE CALLED BY A ISR, it depends on that no other ISR interrupts this
    //store initial pin states
  switch(axis)
  {
  case X_AXIS:
  {
    enable_x();   
    uint8_t old_x_dir_pin= READ(X_DIR_PIN);  //if dualzstepper, both point to same direction.
   
    //setup new step
    WRITE(X_DIR_PIN,(INVERT_X_DIR)^direction);
    
    //perform step 
    WRITE(X_STEP_PIN, !INVERT_X_STEP_PIN); 
#ifdef DEBUG_XSTEP_DUP_PIN
    WRITE(DEBUG_XSTEP_DUP_PIN,!INVERT_X_STEP_PIN);
#endif //DEBUG_XSTEP_DUP_PIN
    delayMicroseconds(1);
    WRITE(X_STEP_PIN, INVERT_X_STEP_PIN);
#ifdef DEBUG_XSTEP_DUP_PIN
    WRITE(DEBUG_XSTEP_DUP_PIN,INVERT_X_STEP_PIN);
#endif //DEBUG_XSTEP_DUP_PIN

    //get old pin state back.
    WRITE(X_DIR_PIN,old_x_dir_pin);
  }
  break;
  case Y_AXIS:
  {
    enable_y();   
    uint8_t old_y_dir_pin= READ(Y_DIR_PIN);  //if dualzstepper, both point to same direction.
   
    //setup new step
    WRITE(Y_DIR_PIN,(INVERT_Y_DIR)^direction);
    
    //perform step 
    WRITE(Y_STEP_PIN, !INVERT_Y_STEP_PIN); 
#ifdef DEBUG_YSTEP_DUP_PIN
    WRITE(DEBUG_YSTEP_DUP_PIN,!INVERT_Y_STEP_PIN);
#endif //DEBUG_YSTEP_DUP_PIN
    delayMicroseconds(1);
    WRITE(Y_STEP_PIN, INVERT_Y_STEP_PIN);
#ifdef DEBUG_YSTEP_DUP_PIN
    WRITE(DEBUG_YSTEP_DUP_PIN,INVERT_Y_STEP_PIN);
#endif //DEBUG_YSTEP_DUP_PIN

    //get old pin state back.
    WRITE(Y_DIR_PIN,old_y_dir_pin);

  }
  break;
 
  case Z_AXIS:
  {
    enable_z();
    uint8_t old_z_dir_pin= READ(Z_DIR_PIN);  //if dualzstepper, both point to same direction.
    //setup new step
    WRITE(Z_DIR_PIN,(INVERT_Z_DIR)^direction^BABYSTEP_INVERT_Z);
    #ifdef Z_DUAL_STEPPER_DRIVERS
      WRITE(Z2_DIR_PIN,(INVERT_Z_DIR)^direction^BABYSTEP_INVERT_Z);
    #endif
    //perform step 
    WRITE(Z_STEP_PIN, !INVERT_Z_STEP_PIN); 
    #ifdef Z_DUAL_STEPPER_DRIVERS
      WRITE(Z2_STEP_PIN, !INVERT_Z_STEP_PIN);
    #endif
    delayMicroseconds(1);
    WRITE(Z_STEP_PIN, INVERT_Z_STEP_PIN);
    #ifdef Z_DUAL_STEPPER_DRIVERS
      WRITE(Z2_STEP_PIN, INVERT_Z_STEP_PIN);
    #endif

    //get old pin state back.
    WRITE(Z_DIR_PIN,old_z_dir_pin);
    #ifdef Z_DUAL_STEPPER_DRIVERS
      WRITE(Z2_DIR_PIN,old_z_dir_pin);
    #endif

  }
  break;
 
  default:    break;
  }
}
#endif //BABYSTEPPING

#if defined(DIGIPOTSS_PIN) && DIGIPOTSS_PIN > -1
void digitalPotWrite(int address, int value) // From Arduino DigitalPotControl example
{
    digitalWrite(DIGIPOTSS_PIN,LOW); // take the SS pin low to select the chip
    SPI.transfer(address); //  send in the address and value via SPI:
    SPI.transfer(value);
    digitalWrite(DIGIPOTSS_PIN,HIGH); // take the SS pin high to de-select the chip:
    //delay(10);
}
#endif

void EEPROM_read_st(int pos, uint8_t* value, uint8_t size)
{
    do
    {
        *value = eeprom_read_byte((unsigned char*)pos);
        pos++;
        value++;
    }while(--size);
}


void st_current_init() //Initialize Digipot Motor Current
{  
uint8_t SilentMode = eeprom_read_byte((uint8_t*)EEPROM_SILENT);
  SilentModeMenu = SilentMode;
  #ifdef MOTOR_CURRENT_PWM_XY_PIN
    pinMode(MOTOR_CURRENT_PWM_XY_PIN, OUTPUT);
    pinMode(MOTOR_CURRENT_PWM_Z_PIN, OUTPUT);
    pinMode(MOTOR_CURRENT_PWM_E_PIN, OUTPUT);
    if((SilentMode == SILENT_MODE_OFF) || (farm_mode) ){

     motor_current_setting[0] = motor_current_setting_loud[0];
     motor_current_setting[1] = motor_current_setting_loud[1];
     motor_current_setting[2] = motor_current_setting_loud[2];

    }else{

     motor_current_setting[0] = motor_current_setting_silent[0];
     motor_current_setting[1] = motor_current_setting_silent[1];
     motor_current_setting[2] = motor_current_setting_silent[2];

    }
    st_current_set(0, motor_current_setting[0]);
    st_current_set(1, motor_current_setting[1]);
    st_current_set(2, motor_current_setting[2]);
    //Set timer5 to 31khz so the PWM of the motor power is as constant as possible. (removes a buzzing noise)
    TCCR5B = (TCCR5B & ~(_BV(CS50) | _BV(CS51) | _BV(CS52))) | _BV(CS50);
  #endif
}



#ifdef MOTOR_CURRENT_PWM_XY_PIN
void st_current_set(uint8_t driver, int current)
{
  if (driver == 0) analogWrite(MOTOR_CURRENT_PWM_XY_PIN, (long)current * 255L / (long)MOTOR_CURRENT_PWM_RANGE);
  if (driver == 1) analogWrite(MOTOR_CURRENT_PWM_Z_PIN, (long)current * 255L / (long)MOTOR_CURRENT_PWM_RANGE);
  if (driver == 2) analogWrite(MOTOR_CURRENT_PWM_E_PIN, (long)current * 255L / (long)MOTOR_CURRENT_PWM_RANGE);
}
#else //MOTOR_CURRENT_PWM_XY_PIN
void st_current_set(uint8_t, int ){}
#endif //MOTOR_CURRENT_PWM_XY_PIN

void microstep_init()
{

  #if defined(E1_MS1_PIN) && E1_MS1_PIN > -1
  pinMode(E1_MS1_PIN,OUTPUT);
  pinMode(E1_MS2_PIN,OUTPUT); 
  #endif

  #if defined(X_MS1_PIN) && X_MS1_PIN > -1
  const uint8_t microstep_modes[] = MICROSTEP_MODES;
  pinMode(X_MS1_PIN,OUTPUT);
  pinMode(X_MS2_PIN,OUTPUT);  
  pinMode(Y_MS1_PIN,OUTPUT);
  pinMode(Y_MS2_PIN,OUTPUT);
  pinMode(Z_MS1_PIN,OUTPUT);
  pinMode(Z_MS2_PIN,OUTPUT);
  pinMode(E0_MS1_PIN,OUTPUT);
  pinMode(E0_MS2_PIN,OUTPUT);
  for(int i=0;i<=4;i++) microstep_mode(i,microstep_modes[i]);
  #endif
}


#ifndef TMC2130

void microstep_ms(uint8_t driver, int8_t ms1, int8_t ms2)
{
  if(ms1 > -1) switch(driver)
  {
    case 0: digitalWrite( X_MS1_PIN,ms1); break;
    case 1: digitalWrite( Y_MS1_PIN,ms1); break;
    case 2: digitalWrite( Z_MS1_PIN,ms1); break;
    case 3: digitalWrite(E0_MS1_PIN,ms1); break;
    #if defined(E1_MS1_PIN) && E1_MS1_PIN > -1
    case 4: digitalWrite(E1_MS1_PIN,ms1); break;
    #endif
  }
  if(ms2 > -1) switch(driver)
  {
    case 0: digitalWrite( X_MS2_PIN,ms2); break;
    case 1: digitalWrite( Y_MS2_PIN,ms2); break;
    case 2: digitalWrite( Z_MS2_PIN,ms2); break;
    case 3: digitalWrite(E0_MS2_PIN,ms2); break;
    #if defined(E1_MS2_PIN) && E1_MS2_PIN > -1
    case 4: digitalWrite(E1_MS2_PIN,ms2); break;
    #endif
  }
}

void microstep_mode(uint8_t driver, uint8_t stepping_mode)
{
  switch(stepping_mode)
  {
    case 1: microstep_ms(driver,MICROSTEP1); break;
    case 2: microstep_ms(driver,MICROSTEP2); break;
    case 4: microstep_ms(driver,MICROSTEP4); break;
    case 8: microstep_ms(driver,MICROSTEP8); break;
    case 16: microstep_ms(driver,MICROSTEP16); break;
  }
}

void microstep_readings()
{
      SERIAL_PROTOCOLPGM("MS1,MS2 Pins\n");
      SERIAL_PROTOCOLPGM("X: ");
      SERIAL_PROTOCOL(   digitalRead(X_MS1_PIN));
      SERIAL_PROTOCOLLN( digitalRead(X_MS2_PIN));
      SERIAL_PROTOCOLPGM("Y: ");
      SERIAL_PROTOCOL(   digitalRead(Y_MS1_PIN));
      SERIAL_PROTOCOLLN( digitalRead(Y_MS2_PIN));
      SERIAL_PROTOCOLPGM("Z: ");
      SERIAL_PROTOCOL(   digitalRead(Z_MS1_PIN));
      SERIAL_PROTOCOLLN( digitalRead(Z_MS2_PIN));
      SERIAL_PROTOCOLPGM("E0: ");
      SERIAL_PROTOCOL(   digitalRead(E0_MS1_PIN));
      SERIAL_PROTOCOLLN( digitalRead(E0_MS2_PIN));
      #if defined(E1_MS1_PIN) && E1_MS1_PIN > -1
      SERIAL_PROTOCOLPGM("E1: ");
      SERIAL_PROTOCOL(   digitalRead(E1_MS1_PIN));
      SERIAL_PROTOCOLLN( digitalRead(E1_MS2_PIN));
      #endif
}
#endif //TMC2130