PrusaFirmware/Firmware/xyzcal.cpp

//xyzcal.cpp - xyz calibration with image processing

#include "Configuration_prusa.h"
#ifdef NEW_XYZCAL

#include "xyzcal.h"
#include <avr/wdt.h>
#include "stepper.h"
#include "temperature.h"
#include "sm4.h"

#define XYZCAL_PINDA_HYST_MIN 20  //50um
#define XYZCAL_PINDA_HYST_MAX 100 //250um
#define XYZCAL_PINDA_HYST_DIF 5   //12.5um

#define ENABLE_FANCHECK_INTERRUPT()  EIMSK |= (1<<7)
#define DISABLE_FANCHECK_INTERRUPT() EIMSK &= ~(1<<7)

#define _PINDA ((READ(Z_MIN_PIN) != Z_MIN_ENDSTOP_INVERTING)?1:0)

static const char endl[2] PROGMEM = "\n";

#define DBG(args...) printf_P(args)
//#define DBG(args...)
#ifndef _n
#define _n PSTR
#endif //_n

#define _X ((int16_t)count_position[X_AXIS])
#define _Y ((int16_t)count_position[Y_AXIS])
#define _Z ((int16_t)count_position[Z_AXIS])
#define _E ((int16_t)count_position[E_AXIS])

#define _X_ (count_position[X_AXIS])
#define _Y_ (count_position[Y_AXIS])
#define _Z_ (count_position[Z_AXIS])
#define _E_ (count_position[E_AXIS])

#ifndef M_PI
const constexpr float M_PI = 3.1415926535897932384626433832795f;
#endif

const constexpr uint8_t X_PLUS = 0;
const constexpr uint8_t X_MINUS = 1;
const constexpr uint8_t Y_PLUS = 0;
const constexpr uint8_t Y_MINUS = 1;
const constexpr uint8_t Z_PLUS = 0;
const constexpr uint8_t Z_MINUS = 1;

const constexpr uint8_t X_PLUS_MASK = 0;
const constexpr uint8_t X_MINUS_MASK = X_AXIS_MASK;
const constexpr uint8_t Y_PLUS_MASK = 0;
const constexpr uint8_t Y_MINUS_MASK = Y_AXIS_MASK;
const constexpr uint8_t Z_PLUS_MASK = 0;
const constexpr uint8_t Z_MINUS_MASK = Z_AXIS_MASK;

/// Max. jerk in PrusaSlicer, 10000 = 1 mm/s
const constexpr uint16_t MAX_DELAY = 10000;
const constexpr float MIN_SPEED = 0.01f / (MAX_DELAY * 0.000001f);
/// 200 = 50 mm/s
const constexpr uint16_t Z_MIN_DELAY = 200;
const constexpr uint16_t Z_ACCEL = 1000;

/// \returns positive value always
#define ABS(a) \
    ({ __typeof__ (a) _a = (a); \
    _a >= 0 ? _a : (-_a); })

/// \returns maximum of the two
#define MAX(a, b) \
    ({ __typeof__ (a) _a = (a); \
    __typeof__ (b) _b = (b); \
    _a >= _b ? _a : _b; })

/// \returns minimum of the two
#define MIN(a, b) \
    ({ __typeof__ (a) _a = (a); \
    __typeof__ (b) _b = (b); \
    _a <= _b ? _a : _b; })

/// swap values
#define SWAP(a, b) \
    ({ __typeof__ (a) c = (a); \
        a = (b); \
        b = c; })

/// Saturates value
/// \returns min if value is less than min
/// \returns max if value is more than min
/// \returns value otherwise
#define CLAMP(value, min, max) \
    ({ __typeof__ (value) a_ = (value); \
		__typeof__ (min) min_ = (min); \
		__typeof__ (max) max_ = (max); \
        ( a_ < min_ ? min_ : (a_ <= max_ ? a_ : max_)); })

/// \returns square of the value
#define SQR(a) \
    ({ __typeof__ (a) a_ = (a); \
        (a_ * a_); })

/// position types
typedef int16_t pos_i16_t;
typedef long pos_i32_t;
typedef float pos_mm_t;
typedef int16_t usteps_t;

uint8_t check_pinda_0();
uint8_t check_pinda_1();
void xyzcal_update_pos(uint16_t dx, uint16_t dy, uint16_t dz, uint16_t de);
uint16_t xyzcal_calc_delay(uint16_t nd, uint16_t dd);

uint8_t round_to_u8(float f){
	return (uint8_t)(f + .5f);
}

uint16_t round_to_u16(float f){
	return (uint16_t)(f + .5f);
}

int16_t round_to_i16(float f){
	return (int16_t)(f + .5f);
}

/// converts millimeters to integer position
pos_i16_t mm_2_pos(pos_mm_t mm){
	return (pos_i16_t)(0.5f + mm * 100);
}

/// converts integer position to millimeters
pos_mm_t pos_2_mm(pos_i16_t pos){
	return pos * 0.01f;
}
pos_mm_t pos_2_mm(float pos){
	return pos * 0.01f;
}

void xyzcal_meassure_enter(void)
{
	DBG(_n("xyzcal_meassure_enter\n"));
	disable_heater();
	DISABLE_TEMPERATURE_INTERRUPT();
#if (defined(FANCHECK) && defined(TACH_1) && (TACH_1 >-1))
	DISABLE_FANCHECK_INTERRUPT();
#endif //(defined(FANCHECK) && defined(TACH_1) && (TACH_1 >-1))
	DISABLE_STEPPER_DRIVER_INTERRUPT();
#ifdef WATCHDOG
	wdt_disable();
#endif //WATCHDOG
	sm4_stop_cb = 0;
	sm4_update_pos_cb = xyzcal_update_pos;
	sm4_calc_delay_cb = xyzcal_calc_delay;
}

void xyzcal_meassure_leave(void)
{
	DBG(_n("xyzcal_meassure_leave\n"));
    planner_abort_hard();
	ENABLE_TEMPERATURE_INTERRUPT();
#if (defined(FANCHECK) && defined(TACH_1) && (TACH_1 >-1))
	ENABLE_FANCHECK_INTERRUPT();
#endif //(defined(FANCHECK) && defined(TACH_1) && (TACH_1 >-1))
	ENABLE_STEPPER_DRIVER_INTERRUPT();
#ifdef WATCHDOG
	wdt_enable(WDTO_4S);
#endif //WATCHDOG
	sm4_stop_cb = 0;
	sm4_update_pos_cb = 0;
	sm4_calc_delay_cb = 0;
}


uint8_t check_pinda_0()
{
	return _PINDA?0:1;
}

uint8_t check_pinda_1()
{
	return _PINDA?1:0;
}

uint8_t xyzcal_dm = 0;

void xyzcal_update_pos(uint16_t dx, uint16_t dy, uint16_t dz, uint16_t)
{
//	DBG(_n("xyzcal_update_pos dx=%d dy=%d dz=%d dir=%02x\n"), dx, dy, dz, xyzcal_dm);
	if (xyzcal_dm&1) count_position[0] -= dx; else count_position[0] += dx;
	if (xyzcal_dm&2) count_position[1] -= dy; else count_position[1] += dy;
	if (xyzcal_dm&4) count_position[2] -= dz; else count_position[2] += dz;
//	DBG(_n(" after xyzcal_update_pos x=%ld y=%ld z=%ld\n"), count_position[0], count_position[1], count_position[2]);
}

uint16_t xyzcal_sm4_delay = 0;

//#define SM4_ACCEL_TEST
#ifdef SM4_ACCEL_TEST
uint16_t xyzcal_sm4_v0 = 2000;
uint16_t xyzcal_sm4_vm = 45000;
uint16_t xyzcal_sm4_v = xyzcal_sm4_v0;
uint16_t xyzcal_sm4_ac = 2000;
uint16_t xyzcal_sm4_ac2 = (uint32_t)xyzcal_sm4_ac * 1024 / 10000;
//float xyzcal_sm4_vm = 10000;
#endif //SM4_ACCEL_TEST

#ifdef SM4_ACCEL_TEST
uint16_t xyzcal_calc_delay(uint16_t nd, uint16_t dd)
{
	uint16_t del_us = 0;
	if (xyzcal_sm4_v & 0xf000) //>=4096
	{
		del_us = (uint16_t)62500 / (uint16_t)(xyzcal_sm4_v >> 4);
		xyzcal_sm4_v += (xyzcal_sm4_ac2 * del_us + 512) >> 10;
		if (xyzcal_sm4_v > xyzcal_sm4_vm) xyzcal_sm4_v = xyzcal_sm4_vm;
		if (del_us > 25) return del_us - 25;
	}
	else
	{
		del_us = (uint32_t)1000000 / xyzcal_sm4_v;
		xyzcal_sm4_v += ((uint32_t)xyzcal_sm4_ac2 * del_us + 512) >> 10;
		if (xyzcal_sm4_v > xyzcal_sm4_vm) xyzcal_sm4_v = xyzcal_sm4_vm;
		if (del_us > 50) return del_us - 50;
	}

//	uint16_t del_us = (uint16_t)(((float)1000000 / xyzcal_sm4_v) + 0.5);		
//	uint16_t del_us = (uint32_t)1000000 / xyzcal_sm4_v;		
//	uint16_t del_us = 100;		
//	uint16_t del_us = (uint16_t)10000 / xyzcal_sm4_v;
//	v += (ac * del_us + 500) / 1000;
//	xyzcal_sm4_v += (xyzcal_sm4_ac * del_us) / 1000;
//	return xyzcal_sm4_delay;
//	DBG(_n("xyzcal_calc_delay nd=%d dd=%d v=%d  del_us=%d\n"), nd, dd, xyzcal_sm4_v, del_us);
	return 0;
}
#else //SM4_ACCEL_TEST
uint16_t xyzcal_calc_delay(uint16_t, uint16_t)
{
    return xyzcal_sm4_delay;
}
#endif //SM4_ACCEL_TEST

/// Moves printer to absolute position [x,y,z] defined in integer position system
/// check_pinda == 0: ordinary move
/// check_pinda == 1: stop when PINDA triggered
/// check_pinda == -1: stop when PINDA untriggered
bool xyzcal_lineXYZ_to(int16_t x, int16_t y, int16_t z, uint16_t delay_us, int8_t check_pinda)
{
//	DBG(_n("xyzcal_lineXYZ_to x=%d y=%d z=%d  check=%d\n"), x, y, z, check_pinda);
	x -= (int16_t)count_position[0];
	y -= (int16_t)count_position[1];
	z -= (int16_t)count_position[2];
	xyzcal_dm = ((x<0)?1:0) | ((y<0)?2:0) | ((z<0)?4:0);
	sm4_set_dir_bits(xyzcal_dm);
	sm4_stop_cb = check_pinda?((check_pinda<0)?check_pinda_0:check_pinda_1):0;
	xyzcal_sm4_delay = delay_us;
	//	uint32_t u = _micros();
	bool ret = sm4_line_xyz_ui(abs(x), abs(y), abs(z)) ? true : false;
	//	u = _micros() - u;
	return ret;
}

/// Moves printer to absolute position [x,y,z] defined in millimeters
bool xyzcal_lineXYZ_to_float(pos_mm_t x, pos_mm_t y, pos_mm_t z, uint16_t delay_us, int8_t check_pinda){
	return xyzcal_lineXYZ_to(mm_2_pos(x), mm_2_pos(y), mm_2_pos(z), delay_us, check_pinda);
}

bool xyzcal_spiral2(int16_t cx, int16_t cy, int16_t z0, int16_t dz, int16_t radius, int16_t rotation, uint16_t delay_us, int8_t check_pinda, uint16_t* pad)
{
	bool ret = false;
	float r = 0; //radius
	uint16_t ad = 0; //angle [deg]
	float ar; //angle [rad]
	uint8_t dad = 0; //delta angle [deg]
	uint8_t dad_min = 4; //delta angle min [deg]
	uint8_t dad_max = 16; //delta angle max [deg]
	uint8_t k = 720 / (dad_max - dad_min); //delta calculation constant
	ad = 0;
	if (pad) ad = *pad % 720;
	
    //@size=214
	DBG(_n("xyzcal_spiral2 cx=%d cy=%d z0=%d dz=%d radius=%d ad=%d\n"), cx, cy, z0, dz, radius, ad);
	// lcd_set_cursor(0, 4);
	// char text[10];
	// snprintf(text, 10, "%4d", z0);
	// lcd_print(text);

	for (; ad < 720; ad++)
	{
		if (radius > 0)
		{
			dad = dad_max - (ad / k);
			r = (float)(((uint32_t)ad) * radius) / 720;
		}
		else
		{
			dad = dad_max - ((719 - ad) / k);
			r = (float)(((uint32_t)(719 - ad)) * (-radius)) / 720;
		}
		ar = radians(ad + rotation);
		int x = (int)(cx + (cos(ar) * r));
		int y = (int)(cy + (sin(ar) * r));
		int z = (int)(z0 - ((float)((int32_t)dz * ad) / 720));
		if (xyzcal_lineXYZ_to(x, y, z, delay_us, check_pinda))
		{
			ad += dad + 1;
			ret = true;
			break;
		}
		ad += dad;
	}
	if (pad) *pad = ad;
	// if(ret){
	// 	lcd_set_cursor(0, 4);
	// 	lcd_print("         ");
	// }
	return ret;
}

bool xyzcal_spiral8(int16_t cx, int16_t cy, int16_t z0, int16_t dz, int16_t radius, uint16_t delay_us, int8_t check_pinda, uint16_t* pad)
{
	bool ret = false;
	uint16_t ad = 0;
	if (pad) ad = *pad;
    //@size=274
	DBG(_n("xyzcal_spiral8 cx=%d cy=%d z0=%d dz=%d radius=%d ad=%d\n"), cx, cy, z0, dz, radius, ad);
	if (!ret && (ad < 720))
		if ((ret = xyzcal_spiral2(cx, cy, z0 - 0*dz, dz, radius, 0, delay_us, check_pinda, &ad)) != 0)
			ad += 0;
	if (!ret && (ad < 1440))
		if ((ret = xyzcal_spiral2(cx, cy, z0 - 1*dz, dz, -radius, 0, delay_us, check_pinda, &ad)) != 0)
			ad += 720;
	if (!ret && (ad < 2160))
		if ((ret = xyzcal_spiral2(cx, cy, z0 - 2*dz, dz, radius, 180, delay_us, check_pinda, &ad)) != 0)
			ad += 1440;
	if (!ret && (ad < 2880))
		if ((ret = xyzcal_spiral2(cx, cy, z0 - 3*dz, dz, -radius, 180, delay_us, check_pinda, &ad)) != 0)
			ad += 2160;
	if (pad) *pad = ad;
	return ret;
}

#ifdef XYZCAL_MEASSURE_PINDA_HYSTEREZIS
int8_t xyzcal_meassure_pinda_hysterezis(int16_t min_z, int16_t max_z, uint16_t delay_us, uint8_t samples)
{
	DBG(_n("xyzcal_meassure_pinda_hysterezis\n"));
	int8_t ret = -1; // PINDA signal error
	int16_t z = _Z;
	int16_t sum_up = 0;
	int16_t sum_dn = 0;
	int16_t up;
	int16_t dn;
	uint8_t sample;
	xyzcal_lineXYZ_to(_X, _Y, min_z, delay_us, 1);
	xyzcal_lineXYZ_to(_X, _Y, max_z, delay_us, -1);
	if (!_PINDA)
	{
		for (sample = 0; sample < samples; sample++)
		{
			dn = _Z;
			if (!xyzcal_lineXYZ_to(_X, _Y, min_z, delay_us, 1)) break;
			dn = dn - _Z;
			up = _Z;
			if (!xyzcal_lineXYZ_to(_X, _Y, max_z, delay_us, -1)) break;
			up = _Z - up;
			DBG(_n("%d. up=%d dn=%d\n"), sample, up, dn);
			sum_up += up;
			sum_dn += dn;
			if (abs(up - dn) > XYZCAL_PINDA_HYST_DIF)
			{
				ret = -2; // difference between up-dn to high
				break;
			}
		}
		if (sample == samples)
		{
			up = sum_up / samples;
			dn = sum_dn / samples;
			uint16_t hyst = (up + dn) / 2;
			if (abs(up - dn) > XYZCAL_PINDA_HYST_DIF)
				ret = -2; // difference between up-dn to high
			else if ((hyst < XYZCAL_PINDA_HYST_MIN) || (hyst > XYZCAL_PINDA_HYST_MAX))
				ret = -3; // hysterezis out of range
			else
				ret = hyst;
		}
	}
	xyzcal_lineXYZ_to(_X, _Y, z, delay_us, 0);
	return ret;
}
#endif //XYZCAL_MEASSURE_PINDA_HYSTEREZIS

void print_hysteresis(int16_t min_z, int16_t max_z, int16_t step){
	int16_t delay_us = 600;
	int16_t trigger = 0;
	int16_t untrigger = 0;
	DBG(_n("Hysteresis\n"));

	xyzcal_lineXYZ_to(_X, _Y, min_z, delay_us, 0);

	for (int16_t z = min_z; z <= max_z; z += step){
		xyzcal_lineXYZ_to(_X, _Y, z, delay_us, -1);
		untrigger = _Z;
		xyzcal_lineXYZ_to(_X, _Y, z, delay_us, 0);
		xyzcal_lineXYZ_to(_X, _Y, min_z, delay_us, 1);
		trigger = _Z;
		//xyzcal_lineXYZ_to(_X, _Y, min_z, delay_us, 0);

        //@size=114
		DBG(_n("min, trigger, untrigger, max: [%d %d %d %d]\n"), _Z, trigger, untrigger, z);
	}
}

void update_position_1_step(uint8_t axis, uint8_t dir){
	if (axis & X_AXIS_MASK)
		_X_ += dir & X_AXIS_MASK ? -1 : 1;
	if (axis & Y_AXIS_MASK)
		_Y_ += dir & Y_AXIS_MASK ? -1 : 1;
	if (axis & Z_AXIS_MASK)
		_Z_ += dir & Z_AXIS_MASK ? -1 : 1;
}

void set_axes_dir(uint8_t axes, uint8_t dir){
	if (axes & X_AXIS_MASK)
		sm4_set_dir(X_AXIS, dir & X_AXIS_MASK);
	if (axes & Y_AXIS_MASK)
		sm4_set_dir(Y_AXIS, dir & Y_AXIS_MASK);
	if (axes & Z_AXIS_MASK)
		sm4_set_dir(Z_AXIS, dir & Z_AXIS_MASK);
}

/// Accelerate up to max.speed (defined by @min_delay_us)
/// does not update global positions
void accelerate_1_step(uint8_t axes, int16_t acc, uint16_t &delay_us, uint16_t min_delay_us){
	sm4_do_step(axes);

	/// keep max speed (avoid extra computation)
	if (acc > 0 && delay_us == min_delay_us){
		delayMicroseconds(delay_us);
		return;
	}

	// v1 = v0 + a * t
	// 0.01 = length of a step
	const float t0 = delay_us * 0.000001f;
	const float v1 = (0.01f / t0 + acc * t0);
	uint16_t t1;
	if (v1 <= 0.16f){ ///< slowest speed convertible to uint16_t delay
		t1 = MAX_DELAY; ///< already too slow so it wants to move back
	} else {
		/// don't exceed max.speed
		t1 = MAX(min_delay_us, round_to_u16(0.01f / v1 * 1000000.f));
	}

	/// make sure delay has changed a bit at least
	if (t1 == delay_us && acc != 0){
		if (acc > 0)
			t1--;
		else
			t1++;
	}
	
	//DBG(_n("%d "), t1);

	delayMicroseconds(t1);
	delay_us = t1;
}

/// Goes defined number of steps while accelerating
/// updates global positions
void accelerate(uint8_t axes, uint8_t dir, int16_t acc, uint16_t &delay_us, uint16_t min_delay_us, uint16_t steps){
	set_axes_dir(axes, dir);
	while (steps--){
		accelerate_1_step(axes, acc, delay_us, min_delay_us);
		update_position_1_step(axes, dir);
	}
}

/// keeps speed and then it decelerates to a complete stop (if possible)
/// it goes defined number of steps
/// returns after each step
/// \returns true if step was done
/// does not update global positions
bool go_and_stop_1_step(uint8_t axes, int16_t dec, uint16_t &delay_us, uint16_t &steps){
	if (steps <= 0 || dec <= 0)
		return false;

	/// deceleration distance in steps, s = 1/2 v^2 / a
	uint16_t s = round_to_u16(100 * 0.5f * SQR(0.01f) / (SQR((float)delay_us) * dec));
	if (steps > s){
		/// go steady
		sm4_do_step(axes);
		delayMicroseconds(delay_us);
	} else {
		/// decelerate
		accelerate_1_step(axes, -dec, delay_us, delay_us);
	}
	--steps;
	return true;
}

/// \param dir sets direction of movement
/// updates global positions
void go_and_stop(uint8_t axes, uint8_t dir, int16_t dec, uint16_t &delay_us, uint16_t steps){
	set_axes_dir(axes, dir);
	while (go_and_stop_1_step(axes, dec, delay_us, steps)){
		update_position_1_step(axes, dir);
	}
}

/// goes all the way to stop
/// \returns steps done
/// updates global positions
void stop_smoothly(uint8_t axes, uint8_t dir, int16_t dec, uint16_t &delay_us){
	if (dec <= 0)
		return;
	set_axes_dir(axes, dir);
	while (delay_us < MAX_DELAY){
		accelerate_1_step(axes, -dec, delay_us, delay_us);
		update_position_1_step(axes, dir);
	}
}

void go_start_stop(uint8_t axes, uint8_t dir, int16_t acc, uint16_t min_delay_us, uint16_t steps){
	if (steps == 0)
		return;
	uint16_t current_delay_us = MAX_DELAY;
	const uint16_t half = steps / 2;
	accelerate(axes, dir, acc, current_delay_us, min_delay_us, half);
	go_and_stop(axes, dir, -acc, current_delay_us, steps - half);
}

/// moves X, Y, Z one after each other
/// starts and ends at 0 speed
void go_manhattan(int16_t x, int16_t y, int16_t z, int16_t acc, uint16_t min_delay_us){
	int32_t length;

	// DBG(_n("x %d -> %d, "), x, _X);
	length = x - _X;
	go_start_stop(X_AXIS_MASK, length < 0 ? X_MINUS_MASK : X_PLUS_MASK, acc, min_delay_us, ABS(length));

	// DBG(_n("y %d -> %d, "), y, _Y);
	length = y - _Y;
	go_start_stop(Y_AXIS_MASK, length < 0 ? Y_MINUS_MASK : Y_PLUS_MASK, acc, min_delay_us, ABS(length));

	// DBG(_n("z %d -> %d\n"), z, _Z);
	length = z - _Z;
	go_start_stop(Z_AXIS_MASK, length < 0 ? Z_MINUS_MASK : Z_PLUS_MASK, acc, min_delay_us, ABS(length));
	// DBG(_n("\n"));
}

void xyzcal_scan_pixels_32x32_Zhop(int16_t cx, int16_t cy, int16_t min_z, int16_t max_z, uint16_t delay_us, uint8_t *pixels){
	if (!pixels)
		return;
	int16_t z_trig;
	uint16_t line_buffer[32];
	uint16_t current_delay_us = MAX_DELAY; ///< defines current speed
	int16_t start_z;
	uint16_t steps_to_go;

	DBG(_n("Scan countdown: "));

	for (uint8_t r = 0; r < 32; r++){ ///< Y axis
		for (uint8_t d = 0; d < 2; ++d){
			go_manhattan((d & 1) ? (cx + 992) : (cx - 992), cy - 992 + r * 64, _Z, Z_ACCEL, Z_MIN_DELAY);
			xyzcal_lineXYZ_to((d & 1) ? (cx + 992) : (cx - 992), cy - 992 + r * 64, _Z, delay_us, 0);
			sm4_set_dir(X_AXIS, d);
            //@size=242
			DBG(_n("%d\n"), 64 - (r * 2 + d)); ///< to keep OctoPrint connection alive

			for (uint8_t c = 0; c < 32; c++){ ///< X axis
				/// move to the next point and move Z up diagonally (if needed)
				current_delay_us = MAX_DELAY;
				const int16_t end_x = ((d & 1) ? 1 : -1) * (64 * (16 - c) - 32) + cx;
				const int16_t length_x = ABS(end_x - _X);
				const int16_t half_x = length_x / 2;
				/// don't go up if PINDA not triggered (optimization)
				const bool up = _PINDA;
				const uint8_t axes = up ? X_AXIS_MASK | Z_AXIS_MASK : X_AXIS_MASK;
				const uint8_t dir = Z_PLUS_MASK | (d & 1 ? X_MINUS_MASK : X_PLUS_MASK);

				accelerate(axes, dir, Z_ACCEL, current_delay_us, Z_MIN_DELAY, half_x);
				go_and_stop(axes, dir, Z_ACCEL, current_delay_us, length_x - half_x);
				
				
				z_trig = min_z;

				/// move up to un-trigger (surpress hysteresis)
				sm4_set_dir(Z_AXIS, Z_PLUS);
				/// speed up from stop, go half the way
				current_delay_us = MAX_DELAY;
				for (start_z = _Z; _Z < (max_z + start_z) / 2; ++_Z_){
					if (!_PINDA){
						break;
					}
					accelerate_1_step(Z_AXIS_MASK, Z_ACCEL, current_delay_us, Z_MIN_DELAY);
				}

				if (_PINDA){
					steps_to_go = MAX(0, max_z - _Z);
					while (_PINDA && _Z < max_z){
						go_and_stop_1_step(Z_AXIS_MASK, Z_ACCEL, current_delay_us, steps_to_go);
						++_Z_;
					}
				}
				stop_smoothly(Z_AXIS_MASK, Z_PLUS_MASK, Z_ACCEL, current_delay_us);

				/// move down to trigger
				sm4_set_dir(Z_AXIS, Z_MINUS);
				/// speed up
				current_delay_us = MAX_DELAY;
				for (start_z = _Z; _Z > (min_z + start_z) / 2; --_Z_){
					if (_PINDA){
						z_trig = _Z;
						break;
					}
					accelerate_1_step(Z_AXIS_MASK, Z_ACCEL, current_delay_us, Z_MIN_DELAY);
				}
				/// slow down
				if (!_PINDA){
					steps_to_go = MAX(0, _Z - min_z);
					while (!_PINDA && _Z > min_z){
						go_and_stop_1_step(Z_AXIS_MASK, Z_ACCEL, current_delay_us, steps_to_go);
						--_Z_;
					}
					z_trig = _Z;
				}
				/// slow down to stop but not lower than min_z
				while (_Z > min_z && current_delay_us < MAX_DELAY){
					accelerate_1_step(Z_AXIS_MASK, -Z_ACCEL, current_delay_us, Z_MIN_DELAY);
					--_Z_;
				}

				if (d == 0){
					line_buffer[c] = (uint16_t)(z_trig - min_z);
				} else {
					/// !!! data reversed in X
					// DBG(_n("%04x"), ((uint32_t)line_buffer[31 - c] + (z_trig - min_z)) / 2);
					/// save average of both directions (filters effect of hysteresis)
					pixels[(uint16_t)r * 32 + (31 - c)] = (uint8_t)MIN((uint32_t)255, ((uint32_t)line_buffer[31 - c] + (z_trig - min_z)) / 2);
				}
			}
		}
	}
	DBG(endl);
}

/// Returns rate of match
/// max match = 132, min match = 0
uint8_t xyzcal_match_pattern_12x12_in_32x32(uint16_t* pattern, uint8_t* pixels, uint8_t c, uint8_t r){
	uint8_t thr = 16;
	uint8_t match = 0;
	for (uint8_t i = 0; i < 12; ++i){
		for (uint8_t j = 0; j < 12; ++j){
			/// skip corners (3 pixels in each)
			if (((i == 0) || (i == 11)) && ((j < 2) || (j >= 10))) continue;
			if (((j == 0) || (j == 11)) && ((i < 2) || (i >= 10))) continue;
			const uint16_t idx = (c + j) + 32 * ((uint16_t)r + i);
			const bool high_pix = pixels[idx] > thr;
			const bool high_pat = pattern[i] & (1 << j);
			if (high_pix == high_pat)
				match++;
		}
	}
	return match;
}

/// Searches for best match of pattern by shifting it
/// Returns rate of match and the best location
/// max match = 132, min match = 0
uint8_t xyzcal_find_pattern_12x12_in_32x32(uint8_t* pixels, uint16_t* pattern, uint8_t* pc, uint8_t* pr){
	if (!pixels || !pattern || !pc || !pr)
		return -1;
	uint8_t max_c = 0;
	uint8_t max_r = 0;
	uint8_t max_match = 0;

	// DBG(_n("Matching:\n"));
	/// pixel precision
	for (uint8_t r = 0; r < (32 - 12); ++r){
		for (uint8_t c = 0; c < (32 - 12); ++c){
			const uint8_t match = xyzcal_match_pattern_12x12_in_32x32(pattern, pixels, c, r);
			if (max_match < match){
				max_c = c;
				max_r = r;
				max_match = match;
			}
			// DBG(_n("%d "), match);
		}
		// DBG(_n("\n"));
	}
    //@size=278
	DBG(_n("Pattern center [%f %f], match %f%%\n"), max_c + 5.5f, max_r + 5.5f, max_match / 1.32f);

	*pc = max_c;
	*pr = max_r;
	return max_match;
}

const uint16_t xyzcal_point_pattern_10[12] PROGMEM = {0x000, 0x0f0, 0x1f8, 0x3fc, 0x7fe, 0x7fe, 0x7fe, 0x7fe, 0x3fc, 0x1f8, 0x0f0, 0x000};
const uint16_t xyzcal_point_pattern_08[12] PROGMEM = {0x000, 0x000, 0x0f0, 0x1f8, 0x3fc, 0x3fc, 0x3fc, 0x3fc, 0x1f8, 0x0f0, 0x000, 0x000};

bool xyzcal_searchZ(void) {
	//@size=118
	DBG(_n("xyzcal_searchZ x=%ld y=%ld z=%ld\n"), count_position[X_AXIS], count_position[Y_AXIS], count_position[Z_AXIS]);
	int16_t x0 = _X;
	int16_t y0 = _Y;
	int16_t z = _Z;
//	int16_t min_z = -6000;
//	int16_t dz = 100;
	while (z > -2300) { //-6mm + 0.25mm
		uint16_t ad = 0;
		if (xyzcal_spiral8(x0, y0, z, 100, 900, 320, 1, &ad)) { //dz=100 radius=900 delay=400
			//@size=82
			DBG(_n(" ON-SIGNAL at x=%d y=%d z=%d ad=%d\n"), _X, _Y, _Z, ad);

			/// return to starting XY position
			/// magic constant, lowers min_z after searchZ to obtain more dense data in scan
			const pos_i16_t lower_z = 72;
			xyzcal_lineXYZ_to(x0, y0, _Z - lower_z, 200, 0);
			return true;
		}
		z -= 400;
	}
	//@size=138
	DBG(_n("xyzcal_searchZ no signal\n x=%ld y=%ld z=%ld\n"), count_position[X_AXIS], count_position[Y_AXIS], count_position[Z_AXIS]);
	return false;
}

/// returns value of any location within data
/// uses bilinear interpolation
float get_value(uint8_t * matrix_32x32, float c, float r){
	if (c <= 0 || r <= 0 || c >= 31 || r >= 31)
		return 0;

	/// calculate weights of nearby points
	const float wc1 = c - floor(c);
	const float wr1 = r - floor(r);
	const float wc0 = 1 - wc1;
	const float wr0 = 1 - wr1;

	const float w00 = wc0 * wr0;
	const float w01 = wc0 * wr1;
	const float w10 = wc1 * wr0;
	const float w11 = wc1 * wr1;

	const uint16_t c0 = c;
	const uint16_t c1 = c0 + 1;
	const uint16_t r0 = r;
	const uint16_t r1 = r0 + 1;

	const uint16_t idx00 = c0 + 32 * r0;
	const uint16_t idx01 = c0 + 32 * r1;
	const uint16_t idx10 = c1 + 32 * r0;
	const uint16_t idx11 = c1 + 32 * r1;

	/// bilinear resampling
	return w00 * matrix_32x32[idx00] + w01 * matrix_32x32[idx01] + w10 * matrix_32x32[idx10] + w11 * matrix_32x32[idx11];
}

const constexpr float m_infinity = -1000.f;

/// replaces the highest number by m_infinity
void remove_highest(float *points, const uint8_t num_points){
	if (num_points <= 0)
		return;

	float max = points[0];
	uint8_t max_i = 0;
	for (uint8_t i = 0; i < num_points; ++i){
		if (max < points[i]){
			max = points[i];
			max_i = i;
		}
	}
	points[max_i] = m_infinity;
}

/// return the highest number in the list
float highest(float *points, const uint8_t num_points){
	if (num_points <= 0)
		return 0;

	float max = points[0];
	for (uint8_t i = 0; i < num_points; ++i){
		if (max < points[i]){
			max = points[i];
		}
	}
	return max;
}

/// slow bubble sort but short
void sort(float *points, const uint8_t num_points){
	/// one direction bubble sort
	for (uint8_t i = 0; i < num_points; ++i){
		for (uint8_t j = 0; j < num_points - i - 1; ++j){
			if (points[j] > points[j + 1])
				SWAP(points[j], points[j + 1]);
		}
	}
	
	// DBG(_n("Sorted: "));
	// for (uint8_t i = 0; i < num_points; ++i)
	// 	DBG(_n("%f "), points[i]);
	// DBG(_n("\n"));
}


/// sort array and returns median value
/// don't send empty array or nullptr
float median(float *points, const uint8_t num_points){
	sort(points, num_points);
	return points[num_points / 2];
}

float __attribute__ ((noinline)) CLAMP_median(float *shifts, uint8_t blocks, float norm){
    const constexpr float max_change = 0.5f; ///< avoids too fast changes (avoid oscillation)
    return CLAMP( median(shifts, blocks) * norm, -max_change, max_change);
}

/// Searches for circle iteratively
/// Uses points on the perimeter. If point is high it pushes circle out of the center (shift or change of radius),
/// otherwise to the center.
/// Algorithm is stopped after fixed number of iterations. Move is limited to 0.5 px per iteration.
void dynamic_circle(uint8_t *matrix_32x32, float &x, float &y, float &r, uint8_t iterations){
	/// circle of 10.5 diameter has 33 in circumference, don't go much above
	const constexpr uint8_t num_points = 33;
	const float pi_2_div_num_points = 2 * M_PI / num_points;
	const constexpr uint8_t target_z = 32; ///< target z height of the circle
	const uint8_t blocks = num_points;
	float shifts_x[blocks];
	float shifts_y[blocks];	
	float shifts_r[blocks];	

	// DBG(_n(" [%f, %f][%f] start circle\n"), x, y, r);

	for (int8_t i = iterations; i > 0; --i){
	
        //@size=128B
		// DBG(_n(" [%f, %f][%f] circle\n"), x, y, r);

		/// read points on the circle
		for (uint8_t p = 0; p < num_points; ++p){
			const float angle = p * pi_2_div_num_points;
			const float height = get_value(matrix_32x32, r * cos(angle) + x, r * sin(angle) + y) - target_z;
			// DBG(_n("%f "), point);

			shifts_x[p] = cos(angle) * height;
			shifts_y[p] = sin(angle) * height;
			shifts_r[p] = height;
		}
		// DBG(_n(" points\n"));

		const float reducer = 32.f; ///< reduces speed of convergency to avoid oscillation
		const float norm = 1.f / reducer;
//		x += CLAMP(median(shifts_x, blocks) * norm, -max_change, max_change);
//		y += CLAMP(median(shifts_y, blocks) * norm, -max_change, max_change);
//		r += CLAMP(median(shifts_r, blocks) * norm * .5f, -max_change, max_change);
        //104B down
        x += CLAMP_median(shifts_x, blocks, norm);
        y += CLAMP_median(shifts_y, blocks, norm);
        r += CLAMP_median(shifts_r, blocks, norm * .5f);

		r = MAX(2, r);

	}
    //@size=118
	DBG(_n(" [%f, %f][%f] final circle\n"), x, y, r);
}

/// Prints matrix in hex to debug output (serial line)
void print_image(const uint8_t *matrix_32x32){
	for (uint8_t y = 0; y < 32; ++y){
		const uint16_t idx_y = y * 32;
		for (uint8_t x = 0; x < 32; ++x){
			DBG(_n("%02x"), matrix_32x32[idx_y + x]);
		}
		DBG(endl);
	}
	DBG(endl);
}

/// Takes two patterns and searches them in matrix32
/// \returns best match
uint8_t find_patterns(uint8_t *matrix32, uint16_t *pattern08, uint16_t *pattern10, uint8_t &col, uint8_t &row){
	uint8_t c08 = 0;
	uint8_t r08 = 0;
	uint8_t match08 = 0;
	uint8_t c10 = 0;
	uint8_t r10 = 0;
	uint8_t match10 = 0;

	match08 = xyzcal_find_pattern_12x12_in_32x32(matrix32, pattern08, &c08, &r08);
	match10 = xyzcal_find_pattern_12x12_in_32x32(matrix32, pattern10, &c10, &r10);

	if (match08 > match10){
		col = c08;
		row = r08;
		return match08;
	}
	
	col = c10;
	row = r10;
	return match10;
}

/// Scan should include normal data.
/// If it's too extreme (00, FF) it could be caused by biased sensor.
/// \return true if data looks normal
bool check_scan(uint8_t *matrix32){
	/// magic constants that define normality
	const int16_t threshold_total = 900;
	const int threshold_extreme = 50;

	int16_t mins = 0;
	int16_t maxs = 0;

	for (int16_t i = 0; i < 32*32;++i){
		if (matrix32[i] == 0) {
			++mins;
		} else if (matrix32[i] == 0xFF){
			++maxs;
		}
	}
	const int16_t rest = 1024 - mins - maxs;

	if (mins + maxs > threshold_total
		&& mins > threshold_extreme
		&& maxs > threshold_extreme
		&& mins > rest
		&& maxs > rest)
		return false;

	return true;
}

/// scans area around the current head location and
/// searches for the center of the calibration pin
BedSkewOffsetDetectionResultType xyzcal_scan_and_process(){
    //@size=44
	// DBG(_n("sizeof(block_buffer)=%d\n"), sizeof(block_t)*BLOCK_BUFFER_SIZE);
	BedSkewOffsetDetectionResultType ret = BED_SKEW_OFFSET_DETECTION_POINT_NOT_FOUND;
	int16_t x = _X;
	int16_t y = _Y;
	const int16_t z = _Z;

	uint8_t *matrix32 = (uint8_t *)block_buffer;
	uint16_t *pattern08 = (uint16_t *)(matrix32 + 32 * 32);
	uint16_t *pattern10 = (uint16_t *)(pattern08 + 12);

	for (uint8_t i = 0; i < 12; i++){
		pattern08[i] = pgm_read_word((uint16_t*)(xyzcal_point_pattern_08 + i));
		pattern10[i] = pgm_read_word((uint16_t*)(xyzcal_point_pattern_10 + i));
	}

	xyzcal_scan_pixels_32x32_Zhop(x, y, z, 2400, 200, matrix32);
	print_image(matrix32);
	if (!check_scan(matrix32))
		return BED_SKEW_OFFSET_DETECTION_POINT_SCAN_FAILED;

	/// SEARCH FOR BINARY CIRCLE
	uint8_t uc = 0;
	uint8_t ur = 0;

	/// max match = 132, 1/2 good = 66, 2/3 good = 88
	if (find_patterns(matrix32, pattern08, pattern10, uc, ur) >= 88){
		/// find precise circle
		/// move to the center of the pattern (+5.5)
		float xf = uc + 5.5f;
		float yf = ur + 5.5f;
		float radius = 4.5f; ///< default radius
		constexpr const uint8_t iterations = 20;
		dynamic_circle(matrix32, xf, yf, radius, iterations);
		if (fabs(xf - (uc + 5.5f)) > 3 || fabs(yf - (ur + 5.5f)) > 3 || fabs(radius - 5) > 3){
			//@size=88
            DBG(_n(" [%f %f][%f] mm divergence\n"), xf - (uc + 5.5f), yf - (ur + 5.5f), radius - 5);
			/// dynamic algorithm diverged, use original position instead
			xf = uc + 5.5f;
			yf = ur + 5.5f;
		}

		/// move to the center of area and convert to position
		xf = (float)x + (xf - 15.5f) * 64;
		yf = (float)y + (yf - 15.5f) * 64;
		//@size=114
        DBG(_n(" [%f %f] mm pattern center\n"), pos_2_mm(xf), pos_2_mm(yf));
		x = round_to_i16(xf);
		y = round_to_i16(yf);
		xyzcal_lineXYZ_to(x, y, z, 200, 0);
		ret = BED_SKEW_OFFSET_DETECTION_POINT_FOUND;
	}

	/// wipe buffer
	for (uint16_t i = 0; i < sizeof(block_t)*BLOCK_BUFFER_SIZE; i++)
		matrix32[i] = 0;
	return ret;
}

BedSkewOffsetDetectionResultType xyzcal_find_bed_induction_sensor_point_xy(void){
	BedSkewOffsetDetectionResultType ret = BED_SKEW_OFFSET_DETECTION_POINT_NOT_FOUND;

    //@size=258
    // DBG(_n("xyzcal_find_bed_induction_sensor_point_xy x=%ld y=%ld z=%ld\n"), count_position[X_AXIS], count_position[Y_AXIS], count_position[Z_AXIS]);
	st_synchronize();

	xyzcal_meassure_enter();
	if (xyzcal_searchZ())
		ret = xyzcal_scan_and_process();
	xyzcal_meassure_leave();
	return ret;
}

#endif //NEW_XYZCAL