From 238b8fd2a3f6e1be9f059e7f1ffb18361a8a7e54 Mon Sep 17 00:00:00 2001
From: Scott Lahteine <sourcetree@thinkyhead.com>
Date: Sat, 18 Mar 2017 10:14:31 -0500
Subject: [PATCH] UBL core and support files

---
 Marlin/G26_Mesh_Validation_Tool.cpp | 1001 ++++++++++++++++++
 Marlin/UBL.h                        |  331 ++++++
 Marlin/UBL_Bed_Leveling.cpp         |  296 ++++++
 Marlin/UBL_G29.cpp                  | 1455 +++++++++++++++++++++++++++
 Marlin/UBL_line_to_destination.cpp  |  553 ++++++++++
 Marlin/hex_print_routines.cpp       |   47 +
 Marlin/hex_print_routines.h         |   33 +
 7 files changed, 3716 insertions(+)
 create mode 100644 Marlin/G26_Mesh_Validation_Tool.cpp
 create mode 100644 Marlin/UBL.h
 create mode 100644 Marlin/UBL_Bed_Leveling.cpp
 create mode 100644 Marlin/UBL_G29.cpp
 create mode 100644 Marlin/UBL_line_to_destination.cpp
 create mode 100644 Marlin/hex_print_routines.cpp
 create mode 100644 Marlin/hex_print_routines.h

diff --git a/Marlin/G26_Mesh_Validation_Tool.cpp b/Marlin/G26_Mesh_Validation_Tool.cpp
new file mode 100644
index 0000000000..5cda27f055
--- /dev/null
+++ b/Marlin/G26_Mesh_Validation_Tool.cpp
@@ -0,0 +1,1001 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (C) 2016 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * 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/>.
+ *
+ */
+
+/**
+ * Marlin Firmware -- G26 - Mesh Validation Tool
+ */
+
+#define EXTRUSION_MULTIPLIER 1.0    // This is too much clutter for the main Configuration.h file  But
+#define RETRACTION_MULTIPLIER 1.0   // some user have expressed an interest in being able to customize
+#define NOZZLE 0.3                  // these numbers for thier printer so they don't need to type all
+#define FILAMENT 1.75               // the options every time they do a Mesh Validation Print.
+#define LAYER_HEIGHT 0.2
+#define PRIME_LENGTH 10.0           // So, we put these number in an easy to find and change place.
+#define BED_TEMP 60.0
+#define HOTEND_TEMP 205.0
+#define OOOOZE_AMOUNT 0.3
+
+#include "Marlin.h"
+#include "Configuration.h"
+#include "planner.h"
+#include "stepper.h"
+#include "temperature.h"
+#include "UBL.h"
+#include "ultralcd.h"
+
+#if ENABLED(AUTO_BED_LEVELING_UBL)
+
+  #define SIZE_OF_INTERSECTION_CIRCLES 5
+  #define SIZE_OF_CROSS_HAIRS 3 // cross hairs inside the circle.  This number should be
+                                // less than SIZE_OR_INTERSECTION_CIRCLES
+
+  /**
+   *   Roxy's G26 Mesh Validation Tool
+   *  
+   *   G26 Is a Mesh Validation Tool intended to provide support for the Marlin Unified Bed Leveling System.
+   *   In order to fully utilize and benefit from the Marlin Unified Bed Leveling System an accurate Mesh must
+   *   be defined.  G29 is designed to allow the user to quickly validate the correctness of her Mesh.  It will
+   *   first heat the bed and nozzle. It will then print lines and circles along the Mesh Cell boundaries and
+   *   the intersections of those lines (respectively).
+   *  
+   *   This action allows the user to immediately see where the Mesh is properly defined and where it needs to
+   *   be edited.  The command will generate the Mesh lines closest to the nozzle's starting position.  Alternatively
+   *   the user can specify the X and Y position of interest with command parameters.  This allows the user to
+   *   focus on a particular area of the Mesh where attention is needed.
+   *  
+   *   B #  Bed   Set the Bed Temperature.  If not specified, a default of 60 C. will be assumed.
+   *  
+   *   C    Current   When searching for Mesh Intersection points to draw, use the current nozzle location
+   *        as the base for any distance comparison.
+   *  
+   *   D    Disable   Disable the Unified Bed Leveling System.  In the normal case the user is invoking this
+   *        command to see how well a Mesh as been adjusted to match a print surface.  In order to do
+   *        this the Unified Bed Leveling System is turned on by the G26 command.  The D parameter
+   *        alters the command's normal behaviour and disables the Unified Bed Leveling System even if
+   *        it is on.
+   *  
+   *   H #  Hotend    Set the Nozzle Temperature.  If not specified, a default of 205 C. will be assumed.
+   *  
+   *   F #  Filament  Used to specify the diameter of the filament being used.  If not specified
+   *        1.75mm filament is assumed.  If you are not getting acceptable results by using the
+   *        'correct' numbers, you can scale this number up or down a little bit to change the amount
+   *        of filament that is being extruded during the printing of the various lines on the bed.
+   *  
+   *   K    Keep-On   Keep the heaters turned on at the end of the command.
+   *  
+   *   L #  Layer   Layer height.  (Height of nozzle above bed)  If not specified .20mm will be used.
+   *  
+   *   Q #  Multiplier  Retraction Multiplier.  Normally not needed.  Retraction defaults to 1.0mm and
+   *        un-retraction is at 1.2mm   These numbers will be scaled by the specified amount
+   *  
+   *   N #  Nozzle    Used to control the size of nozzle diameter.  If not specified, a .4mm nozzle is assumed.
+   *  
+   *   O #  Ooooze    How much your nozzle will Ooooze filament while getting in position to print.  This
+   *        is over kill, but using this parameter will let you get the very first 'cicle' perfect
+   *        so you have a trophy to peel off of the bed and hang up to show how perfectly you have your
+   *        Mesh calibrated.  If not specified, a filament length of .3mm is assumed.
+   *  
+   *   P #  Prime   Prime the nozzle with specified length of filament.  If this parameter is not
+   *        given, no prime action will take place.  If the parameter specifies an amount, that much
+   *        will be purged before continuing.  If no amount is specified the command will start
+   *        purging filament until the user provides an LCD Click and then it will continue with
+   *        printing the Mesh.  You can carefully remove the spent filament with a needle nose
+   *        pliers while holding the LCD Click wheel in a depressed state.
+   *  
+   *   R #  Random    Randomize the order that the circles are drawn on the bed.  The search for the closest
+   *        undrawn cicle is still done.  But the distance to the location for each circle has a
+   *        random number of the size specified added to it.  Specifying R50 will give an interesting
+   *        deviation from the normal behaviour on a 10 x 10 Mesh.
+   *  
+   *   X #  X coordinate  Specify the starting location of the drawing activity.
+   *  
+   *   Y #  Y coordinate  Specify the starting location of the drawing activity.
+   */
+
+  extern int UBL_has_control_of_LCD_Panel;
+  extern float feedrate;
+  //extern bool relative_mode;
+  extern Planner planner;
+  //#if ENABLED(ULTRA_LCD)
+    extern char lcd_status_message[];
+  //#endif
+  extern float destination[];
+  extern void set_destination_to_current();
+  extern void set_current_to_destination();
+  extern float code_value_float();
+  extern bool code_value_bool();
+  extern bool code_has_value();
+  extern void lcd_init();
+  #define PLANNER_XY_FEEDRATE() (min(planner.max_feedrate_mm_s[X_AXIS], planner.max_feedrate_mm_s[Y_AXIS])) //bob
+  bool prepare_move_to_destination_cartesian();
+  void line_to_destination();
+  void line_to_destination(float );
+  void gcode_G28();
+  void sync_plan_position_e();
+  void un_retract_filament();
+  void retract_filament();
+  void look_for_lines_to_connect();
+  bool parse_G26_parameters();
+  void move_to(const float&, const float&, const float&, const float&) ;
+  void print_line_from_here_to_there(float sx, float sy, float sz, float ex, float ey, float ez);
+  bool turn_on_heaters();
+  bool prime_nozzle();
+  void chirp_at_user();
+
+  static uint16_t circle_flags[16], horizontal_mesh_line_flags[16], vertical_mesh_line_flags[16], Continue_with_closest = 0;
+  float G26_E_AXIS_feedrate = 0.020,
+        Random_Deviation = 0.0,
+        Layer_Height = LAYER_HEIGHT;
+
+  bool retracted = false; // We keep track of the state of the nozzle to know if it
+                          // is currently retracted or not.  This allows us to be
+                          // less careful because mis-matched retractions and un-retractions
+                          // won't leave us in a bad state.
+  #if ENABLED(ULTRA_LCD)
+    void lcd_setstatus(const char* message, bool persist);
+  #endif
+
+  float valid_trig_angle(float);
+  mesh_index_pair find_closest_circle_to_print(float, float);
+  void debug_current_and_destination(char *title);
+  void UBL_line_to_destination(const float&, const float&, const float&, const float&, const float&, uint8_t);
+  //uint16_t x_splits = 0xFFFF, uint16_t y_splits = 0xFFFF);  /* needed for the old mesh_buffer_line() routine */
+
+  static float E_Pos_Delta,
+               Extrusion_Multiplier = EXTRUSION_MULTIPLIER,
+               Retraction_Multiplier = RETRACTION_MULTIPLIER,
+               Nozzle = NOZZLE,
+               Filament = FILAMENT,
+               Prime_Length = PRIME_LENGTH,
+               X_Pos, Y_Pos,
+               bed_temp = BED_TEMP,
+               hotend_temp = HOTEND_TEMP,
+               Ooooze_Amount = OOOOZE_AMOUNT;
+
+  int8_t Prime_Flag = 0;
+
+  bool Keep_Heaters_On = false,
+       G26_Debug_flag = false;
+
+  /**
+   * These support functions allow the use of large bit arrays of flags that take very
+   * little RAM. Currently they are limited to being 16x16 in size. Changing the declaration
+   * to unsigned long will allow us to go to 32x32 if higher resolution Mesh's are needed
+   * in the future.
+   */
+  void bit_clear(uint16_t bits[16], uint8_t x, uint8_t y) { CBI(bits[y], x); }
+  void bit_set(uint16_t bits[16], uint8_t x, uint8_t y) { SBI(bits[y], x); }
+  bool is_bit_set(uint16_t bits[16], uint8_t x, uint8_t y) { return TEST(bits[y], x); }
+
+  /**
+   * G26: Mesh Validation Pattern generation.
+   * 
+   * Used to interactively edit UBL's Mesh by placing the
+   * nozzle in a problem area and doing a G29 P4 R command.
+   */
+  void gcode_G26() {
+    float circle_x, circle_y, x, y, xe, ye, tmp,
+          start_angle, end_angle;
+    int   i, xi, yi, lcd_init_counter = 0;
+    mesh_index_pair location;
+
+    if (axis_unhomed_error(true, true, true)) // Don't allow Mesh Validation without homing first
+      gcode_G28();
+
+    if (parse_G26_parameters()) return; // If the paramter parsing did not go OK, we abort the command
+
+    if (current_position[Z_AXIS] < Z_CLEARANCE_BETWEEN_PROBES) {
+      do_blocking_move_to_z(Z_CLEARANCE_BETWEEN_PROBES);
+      stepper.synchronize();
+      set_current_to_destination();
+    }
+
+    if (turn_on_heaters())     // Turn on the heaters, leave the command if anything
+      goto LEAVE;              // has gone wrong.
+
+    axis_relative_modes[E_AXIS] = false;    // Get things setup so we can take control of the
+    //relative_mode = false;                  // planner and stepper motors!
+    current_position[E_AXIS] = 0.0;
+    sync_plan_position_e();
+
+    if (Prime_Flag && prime_nozzle())       // if prime_nozzle() returns an error, we just bail out.
+      goto LEAVE;
+
+    /**
+     *      Bed is preheated
+     *
+     *      Nozzle is at temperature
+     *
+     *      Filament is primed!
+     *
+     *      It's  "Show Time" !!!
+     */
+
+    // Clear all of the flags we need
+    ZERO(circle_flags);
+    ZERO(horizontal_mesh_line_flags);
+    ZERO(vertical_mesh_line_flags);
+
+    //
+    // Move nozzle to the specified height for the first layer
+    //
+    set_destination_to_current();
+    destination[Z_AXIS] = Layer_Height;
+    move_to(destination[X_AXIS], destination[Y_AXIS], destination[Z_AXIS], 0.0);
+    move_to(destination[X_AXIS], destination[Y_AXIS], destination[Z_AXIS], Ooooze_Amount);
+
+    UBL_has_control_of_LCD_Panel = 1; // Take control of the LCD Panel!
+    debug_current_and_destination((char *)"Starting G26 Mesh Validation Pattern.");
+
+    do {
+      if (G29_lcd_clicked()) {                                 // Check if the user wants to stop the Mesh Validation
+        strcpy(lcd_status_message, "Mesh Validation Stopped."); // We can't do lcd_setstatus() without having it continue;
+        while (G29_lcd_clicked()) idle(); // Debounce the switch click
+        #if ENABLED(ULTRA_LCD)
+          lcd_setstatus("Mesh Validation Stopped.", true);
+          lcd_quick_feedback();
+        #endif
+        goto LEAVE;
+      }
+
+      if (Continue_with_closest)
+        location = find_closest_circle_to_print(current_position[X_AXIS], current_position[Y_AXIS]);
+      else
+        location = find_closest_circle_to_print(X_Pos, Y_Pos); // Find the closest Mesh Intersection to where we are now.
+
+      if (location.x_index >= 0 && location.y_index >= 0) {
+        circle_x = blm.map_x_index_to_bed_location(location.x_index);
+        circle_y = blm.map_y_index_to_bed_location(location.y_index);
+
+        // Let's do a couple of quick sanity checks.  We can pull this code out later if we never see it catch a problem
+        #ifdef DELTA
+          if (HYPOT2(circle_x, circle_y) > sq(DELTA_PRINTABLE_RADIUS)) {
+            SERIAL_PROTOCOLLNPGM("?Error: Attempt to print outside of DELTA_PRINTABLE_RADIUS.");
+            goto LEAVE;
+          }
+        #endif
+
+        if (circle_x < X_MIN_POS || circle_x > X_MAX_POS || circle_y < Y_MIN_POS || circle_y > Y_MAX_POS) {
+          SERIAL_PROTOCOLLNPGM("?Error: Attempt to print off the bed.");
+          goto LEAVE;
+        }
+
+        xi = location.x_index;  // Just to shrink the next few lines and make them easier to understand
+        yi = location.y_index;
+
+        if (G26_Debug_flag) {
+          SERIAL_ECHOPGM("   Doing circle at: (xi=");
+          SERIAL_ECHO(xi);
+          SERIAL_ECHOPGM(", yi=");
+          SERIAL_ECHO(yi);
+          SERIAL_ECHOLNPGM(")");
+        }
+
+        start_angle = 0.0;    // assume it is going to be a full circle
+        end_angle   = 360.0;
+        if (xi == 0) {       // Check for bottom edge
+          start_angle = -90.0;
+          end_angle   =  90.0;
+          if (yi == 0)        // it is an edge, check for the two left corners
+            start_angle = 0.0;
+          else if (yi == UBL_MESH_NUM_Y_POINTS - 1)
+            end_angle = 0.0;
+        }
+        else if (xi == UBL_MESH_NUM_X_POINTS - 1) { // Check for top edge
+          start_angle =  90.0;
+          end_angle   = 270.0;
+          if (yi == 0)                  // it is an edge, check for the two right corners
+            end_angle = 180.0;
+          else if (yi == UBL_MESH_NUM_Y_POINTS - 1)
+            start_angle = 180.0;
+        }
+        else if (yi == 0) {
+          start_angle =   0.0;         // only do the top   side of the cirlce
+          end_angle   = 180.0;
+        }
+        else if (yi == UBL_MESH_NUM_Y_POINTS - 1) {
+          start_angle = 180.0;         // only do the bottom side of the cirlce
+          end_angle   = 360.0;
+        }
+
+        /**
+         * Declare and generate a sin() & cos() table to be used during the circle drawing.  This will lighten
+         * the CPU load and make the arc drawing faster and more smooth
+         */
+        float sin_table[360 / 30 + 1], cos_table[360 / 30 + 1];
+        int tmp_div_30;
+        for (i = 0; i <= 360 / 30; i++) {
+          cos_table[i] = SIZE_OF_INTERSECTION_CIRCLES * cos(RADIANS(valid_trig_angle(i * 30.0)));
+          sin_table[i] = SIZE_OF_INTERSECTION_CIRCLES * sin(RADIANS(valid_trig_angle(i * 30.0)));
+        }
+
+        for (tmp = start_angle; tmp < end_angle - 0.1; tmp += 30.0) {
+          tmp_div_30 = tmp / 30.0;
+          if (tmp_div_30 < 0) tmp_div_30 += 360 / 30;
+
+          x = circle_x + cos_table[tmp_div_30];    // for speed, these are now a lookup table entry
+          y = circle_y + sin_table[tmp_div_30];
+
+          if (tmp_div_30 > 11) tmp_div_30 -= 360 / 30;
+          xe = circle_x + cos_table[tmp_div_30 + 1]; // for speed, these are now a lookup table entry
+          ye = circle_y + sin_table[tmp_div_30 + 1];
+          #ifdef DELTA
+            if (HYPOT2(x, y) > sq(DELTA_PRINTABLE_RADIUS))   // Check to make sure this part of
+              continue;                                      // the 'circle' is on the bed.  If
+          #else                                              // not, we need to skip
+            x  = constrain(x, X_MIN_POS + 1, X_MAX_POS - 1);     // This keeps us from bumping the endstops
+            y  = constrain(y, Y_MIN_POS + 1, Y_MAX_POS - 1);
+            xe = constrain(xe, X_MIN_POS + 1, X_MAX_POS - 1);
+            ye = constrain(ye, Y_MIN_POS + 1, Y_MAX_POS - 1);
+          #endif
+
+          if (G26_Debug_flag) {
+            char ccc, *cptr, seg_msg[50], seg_num[10];
+            strcpy(seg_msg, "   segment: ");
+            strcpy(seg_num, "    \n");
+            cptr = (char *) "01234567890ABCDEF????????";
+            ccc = cptr[tmp_div_30];
+            seg_num[1] = ccc;
+            strcat(seg_msg, seg_num);
+            debug_current_and_destination(seg_msg);
+          }
+
+          print_line_from_here_to_there(x, y, Layer_Height, xe, ye, Layer_Height);
+        }
+        lcd_init_counter++;
+        if (lcd_init_counter > 10) {
+          lcd_init_counter = 0;
+          lcd_init(); // Some people's LCD Displays are locking up.  This might help them
+        }
+
+        debug_current_and_destination((char *)"Looking for lines to connect.");
+        look_for_lines_to_connect();
+        debug_current_and_destination((char *)"Done with line connect.");
+      }
+
+      debug_current_and_destination((char *)"Done with current circle.");
+
+    }
+    while (location.x_index >= 0 && location.y_index >= 0) ;
+
+    LEAVE:
+
+    retract_filament();
+    destination[Z_AXIS] = Z_CLEARANCE_BETWEEN_PROBES;                             // Raise the nozzle
+
+    debug_current_and_destination((char *)"ready to do Z-Raise.");
+    move_to( destination[X_AXIS], destination[Y_AXIS], destination[Z_AXIS], 0); // Raise the nozzle
+    debug_current_and_destination((char *)"done doing Z-Raise.");
+
+    destination[X_AXIS] = X_Pos;                                                // Move back to the starting position
+    destination[Y_AXIS] = Y_Pos;
+    destination[Z_AXIS] = Z_CLEARANCE_BETWEEN_PROBES;                             // Keep the nozzle where it is
+
+    move_to(destination[X_AXIS], destination[Y_AXIS], destination[Z_AXIS], 0); // Move back to the starting position
+    debug_current_and_destination((char *)"done doing X/Y move.");
+
+    UBL_has_control_of_LCD_Panel = 0;     // Give back control of the LCD Panel!
+
+    if (!Keep_Heaters_On) {
+      #if HAS_TEMP_BED
+        thermalManager.setTargetBed(0.0);
+      #endif
+      thermalManager.setTargetHotend(0.0, 0);
+    }
+    lcd_init(); // Some people's LCD Displays are locking up.  This might help them
+  }
+
+
+  float valid_trig_angle(float d) {
+    while (d > 360.0) d -= 360.0;
+    while (d < 0.0) d += 360.0;
+    return d;
+  }
+
+  mesh_index_pair find_closest_circle_to_print( float X, float Y) {
+    float f, mx, my, dx, dy, closest = 99999.99;
+    mesh_index_pair return_val;
+
+    return_val.x_index = return_val.y_index = -1;
+
+    for (uint8_t i = 0; i < UBL_MESH_NUM_X_POINTS; i++) {
+      for (uint8_t j = 0; j < UBL_MESH_NUM_Y_POINTS; j++) {
+        if (!is_bit_set(circle_flags, i, j))  {
+          mx = blm.map_x_index_to_bed_location(i);  // We found a circle that needs to be printed
+          my = blm.map_y_index_to_bed_location(j);
+
+          dx = X - mx;        // Get the distance to this intersection
+          dy = Y - my;
+          f = HYPOT(dx, dy);
+
+          dx = X_Pos - mx;                  // It is possible that we are being called with the values
+          dy = Y_Pos - my;                  // to let us find the closest circle to the start position.
+          f += HYPOT(dx, dy) / 15.0;        // But if this is not the case,
+                                            // we are going to add in a small
+                                            // weighting to the distance calculation to help it choose
+                                            // a better place to continue.
+
+          if (Random_Deviation > 1.0)
+            f += random(0.0, Random_Deviation); // Add in the specified amount of Random Noise to our search
+
+          if (f < closest) {
+            closest = f;              // We found a closer location that is still
+            return_val.x_index = i;   // un-printed  --- save the data for it
+            return_val.y_index = j;
+            return_val.distance= closest;
+          }
+        }
+      }
+    }
+    bit_set(circle_flags, return_val.x_index, return_val.y_index);   // Mark this location as done.
+    return return_val;
+  }
+
+  void look_for_lines_to_connect() {
+    float sx, sy, ex, ey;
+
+    for (uint8_t i = 0; i < UBL_MESH_NUM_X_POINTS; i++) {
+      for (uint8_t j = 0; j < UBL_MESH_NUM_Y_POINTS; j++) {
+
+        if (i < UBL_MESH_NUM_X_POINTS) { // We can't connect to anything to the right than UBL_MESH_NUM_X_POINTS.
+                                      // This is already a half circle because we are at the edge of the bed.
+
+          if (is_bit_set(circle_flags, i, j) && is_bit_set(circle_flags, i + 1, j)) { // check if we can do a line to the left
+            if (!is_bit_set(horizontal_mesh_line_flags, i, j)) {
+
+              //
+              // We found two circles that need a horizontal line to connect them
+              // Print it!
+              //
+              sx = blm.map_x_index_to_bed_location(i);
+              sx = sx + SIZE_OF_INTERSECTION_CIRCLES - SIZE_OF_CROSS_HAIRS; // get the right edge of the circle
+              sy = blm.map_y_index_to_bed_location(j);
+
+              ex = blm.map_x_index_to_bed_location(i + 1);
+              ex = ex - SIZE_OF_INTERSECTION_CIRCLES + SIZE_OF_CROSS_HAIRS; // get the left edge of the circle
+              ey = sy;
+
+              sx = constrain(sx, X_MIN_POS + 1, X_MAX_POS - 1);             // This keeps us from bumping the endstops
+              sy = constrain(sy, Y_MIN_POS + 1, Y_MAX_POS - 1);
+              ex = constrain(ex, X_MIN_POS + 1, X_MAX_POS - 1);
+              ey = constrain(ey, Y_MIN_POS + 1, Y_MAX_POS - 1);
+
+              if (G26_Debug_flag) {
+                SERIAL_ECHOPGM(" Connecting with horizontal line (sx=");
+                SERIAL_ECHO(sx);
+                SERIAL_ECHOPGM(", sy=");
+                SERIAL_ECHO(sy);
+                SERIAL_ECHOPGM(") -> (ex=");
+                SERIAL_ECHO(ex);
+                SERIAL_ECHOPGM(", ey=");
+                SERIAL_ECHO(ey);
+                SERIAL_ECHOLNPGM(")");
+                debug_current_and_destination((char *)"Connecting horizontal line.");
+              }
+
+              print_line_from_here_to_there(sx, sy, Layer_Height, ex, ey, Layer_Height);
+              bit_set(horizontal_mesh_line_flags, i, j);   // Mark it as done so we don't do it again
+            }
+          }
+
+          if (j < UBL_MESH_NUM_Y_POINTS) { // We can't connect to anything further back than UBL_MESH_NUM_Y_POINTS.
+                                        // This is already a half circle because we are at the edge  of the bed.
+
+            if (is_bit_set(circle_flags, i, j) && is_bit_set(circle_flags, i, j + 1)) { // check if we can do a line straight down
+              if (!is_bit_set( vertical_mesh_line_flags, i, j)) {
+                //
+                // We found two circles that need a vertical line to connect them
+                // Print it!
+                //
+                sx = blm.map_x_index_to_bed_location(i);
+                sy = blm.map_y_index_to_bed_location(j);
+                sy = sy + SIZE_OF_INTERSECTION_CIRCLES - SIZE_OF_CROSS_HAIRS; // get the top edge of the circle
+
+                ex = sx;
+                ey = blm.map_y_index_to_bed_location(j + 1);
+                ey = ey - SIZE_OF_INTERSECTION_CIRCLES + SIZE_OF_CROSS_HAIRS; // get the bottom edge of the circle
+
+                sx = constrain(sx, X_MIN_POS + 1, X_MAX_POS - 1);             // This keeps us from bumping the endstops
+                sy = constrain(sy, Y_MIN_POS + 1, Y_MAX_POS - 1);
+                ex = constrain(ex, X_MIN_POS + 1, X_MAX_POS - 1);
+                ey = constrain(ey, Y_MIN_POS + 1, Y_MAX_POS - 1);
+
+                if (G26_Debug_flag) {
+                  SERIAL_ECHOPGM(" Connecting with vertical line (sx=");
+                  SERIAL_ECHO(sx);
+                  SERIAL_ECHOPGM(", sy=");
+                  SERIAL_ECHO(sy);
+                  SERIAL_ECHOPGM(") -> (ex=");
+                  SERIAL_ECHO(ex);
+                  SERIAL_ECHOPGM(", ey=");
+                  SERIAL_ECHO(ey);
+                  SERIAL_ECHOLNPGM(")");
+                  debug_current_and_destination((char *)"Connecting vertical line.");
+                }
+                print_line_from_here_to_there(sx, sy, Layer_Height, ex, ey, Layer_Height);
+                bit_set( vertical_mesh_line_flags, i, j);   // Mark it as done so we don't do it again
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+
+  void debug_current_and_destination(char *title) {
+    float dx, dy, de, xy_dist, fpmm;
+
+    // if the title message starts with a '!' it is so important, we are going to
+    // ignore the status of the G26_Debug_Flag
+    if (*title != '!' && !G26_Debug_flag) return;
+
+    dx = current_position[X_AXIS] - destination[X_AXIS];
+    dy = current_position[Y_AXIS] - destination[Y_AXIS];
+    de = destination[E_AXIS] - current_position[E_AXIS];
+    if (de == 0.0) return;
+
+    xy_dist = HYPOT(dx, dy);
+    if (xy_dist == 0.0) {
+      return;
+      //SERIAL_ECHOPGM("   FPMM=");
+      //fpmm = de;
+      //SERIAL_PROTOCOL_F(fpmm, 6);
+    }
+    else {
+      SERIAL_ECHOPGM("   fpmm=");
+      fpmm = de / xy_dist;
+      SERIAL_PROTOCOL_F(fpmm, 6);
+    }
+
+    SERIAL_ECHOPGM("    current=( ");
+    SERIAL_PROTOCOL_F(current_position[X_AXIS], 6);
+    SERIAL_ECHOPGM(", ");
+    SERIAL_PROTOCOL_F(current_position[Y_AXIS], 6);
+    SERIAL_ECHOPGM(", ");
+    SERIAL_PROTOCOL_F(current_position[Z_AXIS], 6);
+    SERIAL_ECHOPGM(", ");
+    SERIAL_PROTOCOL_F(current_position[E_AXIS], 6);
+    SERIAL_ECHOPGM(" )   destination=( ");
+    if (current_position[X_AXIS] == destination[X_AXIS])
+      SERIAL_ECHOPGM("-------------");
+    else
+      SERIAL_PROTOCOL_F(destination[X_AXIS], 6);
+
+    SERIAL_ECHOPGM(", ");
+
+    if (current_position[Y_AXIS] == destination[Y_AXIS])
+      SERIAL_ECHOPGM("-------------");
+    else
+      SERIAL_PROTOCOL_F(destination[Y_AXIS], 6);
+
+    SERIAL_ECHOPGM(", ");
+
+    if (current_position[Z_AXIS] == destination[Z_AXIS])
+      SERIAL_ECHOPGM("-------------");
+    else
+      SERIAL_PROTOCOL_F(destination[Z_AXIS], 6);
+
+    SERIAL_ECHOPGM(", ");
+
+    if (current_position[E_AXIS] == destination[E_AXIS])
+      SERIAL_ECHOPGM("-------------");
+    else
+      SERIAL_PROTOCOL_F(destination[E_AXIS], 6);
+
+    SERIAL_ECHOPGM(" )   ");
+    SERIAL_ECHO(title);
+    SERIAL_EOL;
+
+    SET_INPUT_PULLUP(66); // Roxy's Left Switch is on pin 66.  Right Switch is on pin 65
+
+    //if (been_to_2_6) {
+    //while ((digitalRead(66) & 0x01) != 0)
+    //  idle();
+    //}
+  }
+
+  void move_to(const float &x, const float &y, const float &z, const float &e_delta) {
+    float feed_value;
+    static float last_z = -999.99;
+
+    bool has_XY_component = (x != current_position[X_AXIS] || y != current_position[Y_AXIS]); // Check if X or Y is involved in the movement.
+
+    if (G26_Debug_flag) {
+      SERIAL_ECHOPAIR("in move_to()  has_XY_component:", (int)has_XY_component);
+      SERIAL_EOL;
+    }
+
+    if (z != last_z) {
+
+      if (G26_Debug_flag) {
+        SERIAL_ECHOPAIR("in move_to()  changing Z to ", (int)z);
+        SERIAL_EOL;
+      }
+      last_z = z;
+      feed_value = planner.max_feedrate_mm_s[Z_AXIS]/(3.0);  // Base the feed rate off of the configured Z_AXIS feed rate
+
+      destination[X_AXIS] = current_position[X_AXIS];
+      destination[Y_AXIS] = current_position[Y_AXIS];
+      destination[Z_AXIS] = z;                          // We know the last_z==z or we wouldn't be in this block of code.
+      destination[E_AXIS] = current_position[E_AXIS];
+
+      UBL_line_to_destination(destination[X_AXIS], destination[Y_AXIS], destination[Z_AXIS], destination[E_AXIS], feed_value, 0);
+
+      stepper.synchronize();
+      set_destination_to_current();
+
+      if (G26_Debug_flag)
+        debug_current_and_destination((char *)" in move_to() done with Z move");
+    }
+
+    // Check if X or Y is involved in the movement.
+    // Yes: a 'normal' movement. No: a retract() or un_retract()
+    feed_value = has_XY_component ? PLANNER_XY_FEEDRATE() / 10.0 : planner.max_feedrate_mm_s[E_AXIS] / 1.5;
+
+    if (G26_Debug_flag) {
+      SERIAL_ECHOPAIR("in move_to() feed_value for XY:", feed_value);
+      SERIAL_EOL;
+    }
+
+    destination[X_AXIS] = x;
+    destination[Y_AXIS] = y;
+    destination[E_AXIS] += e_delta;
+
+    if (G26_Debug_flag)
+      debug_current_and_destination((char *)" in move_to() doing last move");
+
+    UBL_line_to_destination(destination[X_AXIS], destination[Y_AXIS], destination[Z_AXIS], destination[E_AXIS], feed_value, 0);
+
+    if (G26_Debug_flag)
+      debug_current_and_destination((char *)" in move_to() after last move");
+
+    stepper.synchronize();
+    set_destination_to_current();
+  }
+
+  void retract_filament() {
+    if (!retracted) { // Only retract if we are not already retracted!
+      retracted = true;
+      if (G26_Debug_flag) SERIAL_ECHOLNPGM(" Decided to do retract.");
+      move_to(destination[X_AXIS], destination[Y_AXIS], destination[Z_AXIS], -1.0 * Retraction_Multiplier);
+      if (G26_Debug_flag) SERIAL_ECHOLNPGM(" Retraction done.");
+    }
+  }
+
+  void un_retract_filament() {
+    if (retracted) { // Only un-retract if we are retracted.
+      move_to(destination[X_AXIS], destination[Y_AXIS], destination[Z_AXIS], 1.2 * Retraction_Multiplier);
+      retracted = false;
+      if (G26_Debug_flag) SERIAL_ECHOLNPGM(" unretract done.");
+    }
+  }
+
+  /**
+   * print_line_from_here_to_there() takes two cartesian coordinates and draws a line from one
+   * to the other.  But there are really three sets of coordinates involved.  The first coordinate
+   * is the present location of the nozzle.  We don't necessarily want to print from this location.
+   * We first need to move the nozzle to the start of line segment where we want to print.  Once
+   * there, we can use the two coordinates supplied to draw the line.
+   *
+   * Note:  Although we assume the first set of coordinates is the start of the line and the second
+   * set of coordinates is the end of the line, it does not always work out that way.  This function
+   * optimizes the movement to minimize the travel distance before it can start printing.  This saves
+   * a lot of time and eleminates a lot of non-sensical movement of the nozzle.   However, it does
+   * cause a lot of very little short retracement of th nozzle when it draws the very first line
+   * segment of a 'circle'.   The time this requires is very short and is easily saved by the other
+   * cases where the optimization comes into play.
+   */
+  void print_line_from_here_to_there( float sx, float sy, float sz, float ex, float ey, float ez) {
+    float dx, dy, dx_s, dy_s, dx_e, dy_e, dist_start, dist_end, Line_Length;
+
+    dx_s = current_position[X_AXIS] - sx;   // find our distance from the start of the actual line segment
+    dy_s = current_position[Y_AXIS] - sy;
+    dist_start = HYPOT2(dx_s, dy_s);        // We don't need to do a sqrt(), we can compare the distance^2
+                                            // to save computation time
+    dx_e = current_position[X_AXIS] - ex;   // find our distance from the end of the actual line segment
+    dy_e = current_position[Y_AXIS] - ey;
+    dist_end = HYPOT2(dx_e, dy_e);
+
+    dx = ex - sx;
+    dy = ey - sy;
+    Line_Length = HYPOT(dx, dy);
+
+    // If the end point of the line is closer to the nozzle, we are going to
+    // flip the direction of this line.   We will print it from the end to the start.
+    // On very small lines we don't do the optimization because it just isn't worth it.
+    //
+    if (dist_end < dist_start && (SIZE_OF_INTERSECTION_CIRCLES) < abs(Line_Length)) {
+      if (G26_Debug_flag)
+        SERIAL_ECHOLNPGM("  Reversing start and end of print_line_from_here_to_there()");
+      print_line_from_here_to_there(ex, ey, ez, sx, sy, sz);
+      return;
+    }
+
+    // Now decide if we should retract.
+
+    if (dist_start > 2.0) {
+      retract_filament();
+      if (G26_Debug_flag)
+        SERIAL_ECHOLNPGM("  filament retracted.");
+    }
+    move_to(sx, sy, sz, 0.0); // Get to the starting point with no extrusion
+
+    E_Pos_Delta = Line_Length * G26_E_AXIS_feedrate * Extrusion_Multiplier;
+
+    un_retract_filament();
+    if (G26_Debug_flag) {
+      SERIAL_ECHOLNPGM("  doing printing move.");
+      debug_current_and_destination((char *)"doing final move_to() inside print_line_from_here_to_there()");
+    }
+    move_to(ex, ey, ez, E_Pos_Delta);  // Get to the ending point with an appropriate amount of extrusion
+  }
+
+  /**
+   * This function used to be inline code in G26. But there are so many
+   * parameters it made sense to turn them into static globals and get
+   * this code out of sight of the main routine.
+   */
+  bool parse_G26_parameters() {
+
+    Extrusion_Multiplier  = EXTRUSION_MULTIPLIER;
+    Retraction_Multiplier = RETRACTION_MULTIPLIER;
+    Nozzle                = NOZZLE;
+    Filament              = FILAMENT;
+    Layer_Height          = LAYER_HEIGHT;
+    Prime_Length          = PRIME_LENGTH;
+    bed_temp              = BED_TEMP;
+    hotend_temp           = HOTEND_TEMP;
+    Ooooze_Amount         = OOOOZE_AMOUNT;
+    Prime_Flag            = 0;
+    Keep_Heaters_On       = false;
+
+    if (code_seen('B')) {
+      bed_temp = code_value_float();
+      if (bed_temp < 15.0 || bed_temp > 140.0) {
+        SERIAL_PROTOCOLLNPGM("?Specified bed temperature not plausible.");
+        return UBL_ERR;
+      }
+    }
+
+    if (code_seen('C')) Continue_with_closest++;
+
+    if (code_seen('L')) {
+      Layer_Height = code_value_float();
+      if (Layer_Height<0.0 || Layer_Height>2.0) {
+        SERIAL_PROTOCOLLNPGM("?Specified layer height not plausible.");
+        return UBL_ERR;
+      }
+    }
+
+    if (code_seen('Q')) {
+      if (code_has_value()) {
+        Retraction_Multiplier = code_value_float();
+        if (Retraction_Multiplier<.05 || Retraction_Multiplier>15.0) {
+          SERIAL_PROTOCOLLNPGM("?Specified Retraction Multiplier not plausible.");
+          return UBL_ERR;
+        }
+      }
+      else {
+        SERIAL_PROTOCOLLNPGM("?Retraction Multiplier must be specified.");
+        return UBL_ERR;
+      }
+    }
+
+    if (code_seen('N')) {
+      Nozzle = code_value_float();
+      if (Nozzle < 0.1 || Nozzle > 1.0) {
+        SERIAL_PROTOCOLLNPGM("?Specified nozzle size not plausible.");
+        return UBL_ERR;
+      }
+    }
+
+    if (code_seen('K')) Keep_Heaters_On++;
+
+    if (code_seen('O') && code_has_value())
+      Ooooze_Amount = code_value_float();
+
+    if (code_seen('P')) {
+      if (!code_has_value())
+        Prime_Flag = -1;
+      else {
+        Prime_Flag++;
+        Prime_Length = code_value_float();
+        if (Prime_Length < 0.0 || Prime_Length > 25.0) {
+          SERIAL_PROTOCOLLNPGM("?Specified prime length not plausible.");
+          return UBL_ERR;
+        }
+      }
+    }
+
+    if (code_seen('F')) {
+      Filament = code_value_float();
+      if (Filament < 1.0 || Filament > 4.0) {
+        SERIAL_PROTOCOLLNPGM("?Specified filament size not plausible.");
+        return UBL_ERR;
+      }
+    }
+    Extrusion_Multiplier *= sq(1.75) / sq(Filament);  // If we aren't using 1.75mm filament, we need to
+                                                              // scale up or down the length needed to get the
+                                                              // same volume of filament
+    Extrusion_Multiplier *= Filament * sq(Nozzle) / sq(0.3); // Scale up by nozzle size
+
+    if (code_seen('H')) {
+      hotend_temp = code_value_float();
+      if (hotend_temp < 165.0 || hotend_temp > 280.0) {
+        SERIAL_PROTOCOLLNPGM("?Specified nozzle temperature not plausible.");
+        return UBL_ERR;
+      }
+    }
+
+    if (code_seen('R')) {
+      randomSeed(millis());
+      Random_Deviation = code_has_value() ? code_value_float() : 50.0;
+    }
+
+    X_Pos = current_position[X_AXIS];
+    Y_Pos = current_position[Y_AXIS];
+
+    if (code_seen('X')) {
+      X_Pos = code_value_float();
+      if (X_Pos < X_MIN_POS || X_Pos > X_MAX_POS) {
+        SERIAL_PROTOCOLLNPGM("?Specified X coordinate not plausible.");
+        return UBL_ERR;
+      }
+    }
+    else
+
+    if (code_seen('Y')) {
+      Y_Pos = code_value_float();
+      if (Y_Pos < Y_MIN_POS || Y_Pos > Y_MAX_POS) {
+        SERIAL_PROTOCOLLNPGM("?Specified Y coordinate not plausible.");
+        return UBL_ERR;
+      }
+    }
+
+    /**
+     * We save the question of what to do with the Unified Bed Leveling System's Activation until the very
+     * end.  The reason is, if one of the parameters specified up above is incorrect, we don't want to
+     * alter the system's status.  We wait until we know everything is correct before altering the state
+     * of the system.
+     */
+    blm.state.active = !code_seen('D');
+
+    return UBL_OK;
+  }
+
+  /**
+   * Turn on the bed and nozzle heat and
+   * wait for them to get up to temperature.
+   */
+  bool turn_on_heaters() {
+    #if HAS_TEMP_BED
+      #if ENABLED(ULTRA_LCD)
+        if (bed_temp > 25) {
+          lcd_setstatus("G26 Heating Bed.", true);
+          lcd_quick_feedback();
+      #endif
+          UBL_has_control_of_LCD_Panel++;
+          thermalManager.setTargetBed(bed_temp);
+          while (abs(thermalManager.degBed() - bed_temp) > 3) {
+            if (G29_lcd_clicked()) {
+              strcpy(lcd_status_message, "Leaving G26"); // We can't do lcd_setstatus() without having it continue;
+              while (G29_lcd_clicked()) idle();          // Debounce the switch
+              lcd_setstatus("Leaving G26", true);        // Now we do it right.
+              return UBL_ERR;
+            }
+            idle();
+          }
+      #if ENABLED(ULTRA_LCD)
+        }
+        lcd_setstatus("G26 Heating Nozzle.", true);
+        lcd_quick_feedback();
+      #endif
+    #endif
+
+    // Start heating the nozzle and wait for it to reach temperature.
+    thermalManager.setTargetHotend(hotend_temp, 0);
+    while (abs(thermalManager.degHotend(0) - hotend_temp) > 3) {
+      if (G29_lcd_clicked()) {
+        strcpy(lcd_status_message, "Leaving G26"); // We can't do lcd_setstatus() without having it continue;
+        while (G29_lcd_clicked()) idle();          // Debounce the switch
+        lcd_setstatus("Leaving G26", true);        // Now we do it right.
+        return UBL_ERR;
+      }
+      idle();
+    }
+
+    #if ENABLED(ULTRA_LCD)
+      lcd_setstatus("", true);
+      lcd_quick_feedback();
+    #endif
+    return UBL_OK;
+  }
+
+  /**
+   * Prime the nozzle if needed. Return true on error.
+   */
+  bool prime_nozzle() {
+    float Total_Prime = 0.0;
+
+    if (Prime_Flag == -1) {  // The user wants to control how much filament gets purged
+      lcd_setstatus("User Controled Prime", true);
+      chirp_at_user();
+
+      set_destination_to_current();
+
+      un_retract_filament();    // Lets make sure the G26 command doesn't think the filament is
+                                // retracted().  We are here because we want to prime the nozzle.
+                                // So let's just unretract just to be sure.
+
+      UBL_has_control_of_LCD_Panel++;
+      while (!G29_lcd_clicked()) {
+        chirp_at_user();
+        destination[E_AXIS] += 0.25;
+        #ifdef PREVENT_LENGTHY_EXTRUDE
+          Total_Prime += 0.25;
+          if (Total_Prime >= EXTRUDE_MAXLENGTH) return UBL_ERR;
+        #endif
+        UBL_line_to_destination(
+          destination[X_AXIS], destination[Y_AXIS], destination[Z_AXIS], destination[E_AXIS],
+          //planner.max_feedrate_mm_s[E_AXIS] / 15.0, 0, 0xFFFF, 0xFFFF);
+          planner.max_feedrate_mm_s[E_AXIS] / 15.0, 0
+        );
+
+        stepper.synchronize();    // Without this synchronize, the purge is more consistent,
+                                  // but because the planner has a buffer, we won't be able
+                                  // to stop as quickly.  So we put up with the less smooth
+                                  // action to give the user a more responsive 'Stop'.
+        set_destination_to_current();
+        idle();
+      }
+
+      strcpy(lcd_status_message, "Done Priming"); // We can't do lcd_setstatus() without having it continue;
+                                                  // So...  We cheat to get a message up.
+
+      while (G29_lcd_clicked()) idle(); // Debounce the switch
+
+      #if ENABLED(ULTRA_LCD)
+        UBL_has_control_of_LCD_Panel = 0;
+        lcd_setstatus("Done Priming", true);      // Now we do it right.
+        lcd_quick_feedback();
+      #endif
+    }
+    else {
+      #if ENABLED(ULTRA_LCD)
+        lcd_setstatus("Fixed Length Prime.", true);
+        lcd_quick_feedback();
+      #endif
+      set_destination_to_current();
+      destination[E_AXIS] += Prime_Length;
+      UBL_line_to_destination(
+        destination[X_AXIS], destination[Y_AXIS], destination[Z_AXIS], destination[E_AXIS],
+        //planner.max_feedrate_mm_s[E_AXIS] / 15.0, 0, 0xFFFF, 0xFFFF);
+        planner.max_feedrate_mm_s[E_AXIS] / 15.0, 0
+      );
+      stepper.synchronize();
+      set_destination_to_current();
+      retract_filament();
+    }
+    return UBL_OK;
+  }
+
+#endif // AUTO_BED_LEVELING_UBL
diff --git a/Marlin/UBL.h b/Marlin/UBL.h
new file mode 100644
index 0000000000..2c26276288
--- /dev/null
+++ b/Marlin/UBL.h
@@ -0,0 +1,331 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (C) 2016, 2017 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * 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/>.
+ *
+ */
+
+#include "Marlin.h"
+#include "math.h"
+
+#ifndef UNIFIED_BED_LEVELING_H
+#define UNIFIED_BED_LEVELING_H
+
+  #if ENABLED(AUTO_BED_LEVELING_UBL)
+
+    #define UBL_OK false
+    #define UBL_ERR true
+
+    typedef struct {
+      int x_index, y_index;
+      float distance; // Not always used. But when populated, it is the distance
+                      // from the search location
+    } mesh_index_pair;
+
+    struct vector { double dx, dy, dz; };
+
+    enum Mesh_Point_Type { INVALID, REAL, SET_IN_BITMAP };
+
+    bool axis_unhomed_error(bool, bool, bool);
+    void dump(char *str, float f);
+    bool G29_lcd_clicked();
+    void probe_entire_mesh(float, float, bool, bool);
+    void UBL_line_to_destination(const float&, const float&, const float&, const float&, const float&, uint8_t);
+    void manually_probe_remaining_mesh(float, float, float, float, bool);
+    struct vector tilt_mesh_based_on_3pts(float, float, float);
+    void new_set_bed_level_equation_3pts(float, float, float);
+    float measure_business_card_thickness(float);
+    mesh_index_pair find_closest_mesh_point_of_type(Mesh_Point_Type, float, float, bool, unsigned int[16]);
+    void Find_Mean_Mesh_Height();
+    void Shift_Mesh_Height();
+    bool G29_Parameter_Parsing();
+    void G29_What_Command();
+    void G29_EEPROM_Dump();
+    void G29_Kompare_Current_Mesh_to_Stored_Mesh();
+    void fine_tune_mesh(float, float, float, bool);
+    void bit_clear(uint16_t bits[16], uint8_t x, uint8_t y);
+    void bit_set(uint16_t bits[16], uint8_t x, uint8_t y);
+    bool is_bit_set(uint16_t bits[16], uint8_t x, uint8_t y);
+    char *ftostr43sign(const float&, char);
+
+    void gcode_G26();
+    void gcode_G28();
+    void gcode_G29();
+    extern char conv[9];
+
+    void save_UBL_active_state_and_disable();
+    void restore_UBL_active_state_and_leave();
+
+    ///////////////////////////////////////////////////////////////////////////////////////////////////////
+
+    #if ENABLED(ULTRA_LCD)
+      extern char lcd_status_message[];
+      void lcd_quick_feedback();
+    #endif
+
+    enum MBLStatus { MBL_STATUS_NONE = 0, MBL_STATUS_HAS_MESH_BIT = 0, MBL_STATUS_ACTIVE_BIT = 1 };
+
+    #define MESH_X_DIST ((float(UBL_MESH_MAX_X) - float(UBL_MESH_MIN_X)) / (float(UBL_MESH_NUM_X_POINTS) - 1.0))
+    #define MESH_Y_DIST ((float(UBL_MESH_MAX_Y) - float(UBL_MESH_MIN_Y)) / (float(UBL_MESH_NUM_Y_POINTS) - 1.0))
+
+    extern bool G26_Debug_flag;
+    extern float last_specified_z;
+    extern float fade_scaling_factor_for_current_height;
+    extern float z_values[UBL_MESH_NUM_X_POINTS][UBL_MESH_NUM_Y_POINTS];
+    extern float mesh_index_to_X_location[UBL_MESH_NUM_X_POINTS + 1]; // +1 just because of paranoia that we might end up on the
+    extern float mesh_index_to_Y_location[UBL_MESH_NUM_Y_POINTS + 1]; // the last Mesh Line and that is the start of a whole new cell
+
+    class bed_leveling {
+      public:
+      struct ubl_state {
+        bool active = false;
+        float z_offset = 0.0;
+        int EEPROM_storage_slot = -1,
+            n_x = UBL_MESH_NUM_X_POINTS,
+            n_y = UBL_MESH_NUM_Y_POINTS;
+        float mesh_x_min = UBL_MESH_MIN_X,
+              mesh_y_min = UBL_MESH_MIN_Y,
+              mesh_x_max = UBL_MESH_MAX_X,
+              mesh_y_max = UBL_MESH_MAX_Y,
+              mesh_x_dist = MESH_X_DIST,
+              mesh_y_dist = MESH_Y_DIST,
+              G29_Correction_Fade_Height = 10.0,
+              G29_Fade_Height_Multiplier = 1.0 / 10.0; // It is cheaper to do a floating point multiply than a floating
+                                                       // point divide. So, we keep this number in both forms. The first
+                                                       // is for the user. The second one is the one that is actually used
+                                                       // again and again and again during the correction calculations.
+
+        unsigned char padding[24];  // This is just to allow room to add state variables without
+                                    // changing the location of data structures in the EEPROM.
+                                    // This is for compatability with future versions to keep
+                                    // people from having to regenerate thier mesh data.
+                                    //
+                                    // If you change the contents of this struct, please adjust
+                                    // the padding[] to keep the size the same!
+      } state, pre_initialized;
+
+      bed_leveling();
+      //  ~bed_leveling();  // No destructor because this object never goes away!
+
+      void display_map(int);
+
+      void reset();
+      void invalidate();
+
+      void store_state();
+      void load_state();
+      void store_mesh(int);
+      void load_mesh(int);
+
+      bool sanity_check();
+
+      FORCE_INLINE float map_x_index_to_bed_location(int8_t i){ return ((float) UBL_MESH_MIN_X) + (((float) MESH_X_DIST) * (float) i); };
+      FORCE_INLINE float map_y_index_to_bed_location(int8_t i){ return ((float) UBL_MESH_MIN_Y) + (((float) MESH_Y_DIST) * (float) i); };
+
+      void set_z(const int8_t px, const int8_t py, const float z) { z_values[px][py] = z; }
+
+      int8_t get_cell_index_x(float x) {
+        int8_t cx = (x - (UBL_MESH_MIN_X)) * (1.0 / (MESH_X_DIST));
+        return constrain(cx, 0, (UBL_MESH_NUM_X_POINTS) - 1);   // -1 is appropriate if we want all movement to the X_MAX
+      }                                                         // position. But with this defined this way, it is possible
+                                                                // to extrapolate off of this point even further out. Probably
+                                                                // that is OK because something else should be keeping that from
+                                                                // happening and should not be worried about at this level.
+      int8_t get_cell_index_y(float y) {
+        int8_t cy = (y - (UBL_MESH_MIN_Y)) * (1.0 / (MESH_Y_DIST));
+        return constrain(cy, 0, (UBL_MESH_NUM_Y_POINTS) - 1);   // -1 is appropriate if we want all movement to the Y_MAX
+      }                                                         // position. But with this defined this way, it is possible
+                                                                // to extrapolate off of this point even further out. Probably
+                                                                // that is OK because something else should be keeping that from
+                                                                // happening and should not be worried about at this level.
+
+      int8_t find_closest_x_index(float x) {
+        int8_t px = (x - (UBL_MESH_MIN_X) + (MESH_X_DIST) * 0.5) * (1.0 / (MESH_X_DIST));
+        return (px >= 0 && px < (UBL_MESH_NUM_X_POINTS)) ? px : -1;
+      }
+
+      int8_t find_closest_y_index(float y) {
+        int8_t py = (y - (UBL_MESH_MIN_Y) + (MESH_Y_DIST) * 0.5) * (1.0 / (MESH_Y_DIST));
+        return (py >= 0 && py < (UBL_MESH_NUM_Y_POINTS)) ? py : -1;
+      }
+
+      /**
+       *                           z2   --|
+       *                 z0        |      |
+       *                  |        |      + (z2-z1)
+       *   z1             |        |      |
+       * ---+-------------+--------+--  --|
+       *   a1            a0        a2
+       *    |<---delta_a---------->|
+       *
+       *  calc_z0 is the basis for all the Mesh Based correction. It is used to
+       *  find the expected Z Height at a position between two known Z-Height locations
+       *
+       *  It is farly expensive with its 4 floating point additions and 2 floating point
+       *  multiplications.
+       */
+      inline float calc_z0(float a0, float a1, float z1, float a2, float z2) {
+        float delta_z = (z2 - z1);
+        float delta_a = (a0 - a1) / (a2 - a1);
+        return z1 + delta_a * delta_z;
+      }
+
+      /**
+       * get_z_correction_at_Y_intercept(float x0, int x1_i, int yi) only takes
+       * three parameters. It assumes the x0 point is on a Mesh line denoted by yi. In theory
+       * we could use get_cell_index_x(float x) to obtain the 2nd parameter x1_i but any code calling
+       * the get_z_correction_along_vertical_mesh_line_at_specific_X routine  will already have
+       * the X index of the x0 intersection available and we don't want to perform any extra floating
+       * point operations.
+       */
+      inline float get_z_correction_along_horizontal_mesh_line_at_specific_X(float x0, int x1_i, int yi) {
+        if (x1_i < 0 || yi < 0 || x1_i >= UBL_MESH_NUM_X_POINTS || yi >= UBL_MESH_NUM_Y_POINTS) {
+          SERIAL_ECHOPAIR("? in get_z_correction_along_horizontal_mesh_line_at_specific_X(x0=", x0);
+          SERIAL_ECHOPAIR(",x1_i=", x1_i);
+          SERIAL_ECHOPAIR(",yi=", yi);
+          SERIAL_CHAR(')');
+          SERIAL_EOL;
+          return NAN;
+        }
+
+        const float a0ma1diva2ma1 = (x0 - mesh_index_to_X_location[x1_i]) * (1.0 / (MESH_X_DIST)),
+                    z1 = z_values[x1_i][yi],
+                    z2 = z_values[x1_i + 1][yi],
+                    dz = (z2 - z1);
+
+        return z1 + a0ma1diva2ma1 * dz;
+      }
+
+      //
+      // See comments above for get_z_correction_along_horizontal_mesh_line_at_specific_X
+      //
+      inline float get_z_correction_along_vertical_mesh_line_at_specific_Y(float y0, int xi, int y1_i) {
+        if (xi < 0 || y1_i < 0 || xi >= UBL_MESH_NUM_X_POINTS || y1_i >= UBL_MESH_NUM_Y_POINTS) {
+          SERIAL_ECHOPAIR("? in get_z_correction_along_vertical_mesh_line_at_specific_X(y0=", y0);
+          SERIAL_ECHOPAIR(", x1_i=", xi);
+          SERIAL_ECHOPAIR(", yi=", y1_i);
+          SERIAL_CHAR(')');
+          SERIAL_EOL;
+          return NAN;
+        }
+
+        const float a0ma1diva2ma1 = (y0 - mesh_index_to_Y_location[y1_i]) * (1.0 / (MESH_Y_DIST)),
+                    z1 = z_values[xi][y1_i],
+                    z2 = z_values[xi][y1_i + 1],
+                    dz = (z2 - z1);
+
+        return z1 + a0ma1diva2ma1 * dz;
+      }
+
+      /**
+       * This is the generic Z-Correction. It works anywhere within a Mesh Cell. It first
+       * does a linear interpolation along both of the bounding X-Mesh-Lines to find the
+       * Z-Height at both ends. Then it does a linear interpolation of these heights based
+       * on the Y position within the cell.
+       */
+      float get_z_correction(float x0, float y0) {
+        int8_t cx = get_cell_index_x(x0),
+        cy = get_cell_index_y(y0);
+
+        if (cx < 0 || cy < 0 || cx >= UBL_MESH_NUM_X_POINTS || cy >= UBL_MESH_NUM_Y_POINTS) {
+
+          SERIAL_ECHOPAIR("? in get_z_correction(x0=", x0);
+          SERIAL_ECHOPAIR(", y0=", y0);
+          SERIAL_CHAR(')');
+          SERIAL_EOL;
+
+          #if ENABLED(ULTRA_LCD)
+            strcpy(lcd_status_message, "get_z_correction() indexes out of range.");
+            lcd_quick_feedback();
+          #endif
+          return 0.0; // this used to return state.z_offset
+        }
+
+        float z1 = calc_z0(x0,
+          map_x_index_to_bed_location(cx), z_values[cx][cy],
+          map_x_index_to_bed_location(cx + 1), z_values[cx + 1][cy]);
+        float z2 = calc_z0(x0,
+          map_x_index_to_bed_location(cx), z_values[cx][cy + 1],
+          map_x_index_to_bed_location(cx + 1), z_values[cx + 1][cy + 1]);
+        float z0 = calc_z0(y0,
+          map_y_index_to_bed_location(cy), z1,
+          map_y_index_to_bed_location(cy + 1), z2);
+
+        #if ENABLED(DEBUG_LEVELING_FEATURE)
+          if (DEBUGGING(MESH_ADJUST)) {
+            SERIAL_ECHOPAIR(" raw get_z_correction(", x0);
+            SERIAL_ECHOPAIR(",", y0);
+            SERIAL_ECHOPGM(")=");
+            SERIAL_PROTOCOL_F(z0, 6);
+          }
+        #endif
+
+        #if ENABLED(DEBUG_LEVELING_FEATURE)
+          if (DEBUGGING(MESH_ADJUST)) {
+            SERIAL_ECHOPGM(" >>>---> ");
+            SERIAL_PROTOCOL_F(z0, 6);
+            SERIAL_EOL;
+          }
+        #endif
+
+        if (isnan(z0)) { // if part of the Mesh is undefined, it will show up as NAN
+          z0 = 0.0;      // in blm.z_values[][] and propagate through the
+                         // calculations. If our correction is NAN, we throw it out
+                         // because part of the Mesh is undefined and we don't have the
+                         // information we need to complete the height correction.
+
+          #if ENABLED(DEBUG_LEVELING_FEATURE)
+            if (DEBUGGING(MESH_ADJUST)) {
+              SERIAL_ECHOPGM("??? Yikes!  NAN in get_z_correction( ");
+              SERIAL_ECHO(x0);
+              SERIAL_ECHOPGM(", ");
+              SERIAL_ECHO(y0);
+              SERIAL_ECHOLNPGM(" )");
+            }
+          #endif
+        }
+        return z0; // there used to be a +state.z_offset on this line
+      }
+
+      /**
+       * This routine is used to scale the Z correction depending upon the current nozzle height. It is
+       * optimized for speed. It avoids floating point operations by checking if the requested scaling
+       * factor is going to be the same as the last time the function calculated a value. If so, it just
+       * returns it.
+       *
+       * If it must do a calcuation, it will return a scaling factor of 0.0 if the UBL System is not active
+       * or if the current Z Height is past the specified 'Fade Height'
+       */
+      FORCE_INLINE float fade_scaling_factor_for_Z(float current_z) {
+        if (last_specified_z == current_z)
+          return fade_scaling_factor_for_current_height;
+
+        last_specified_z = current_z;
+        fade_scaling_factor_for_current_height =
+          state.active && current_z < state.G29_Correction_Fade_Height
+          ? 1.0 - (current_z * state.G29_Fade_Height_Multiplier)
+          : 0.0;
+        return fade_scaling_factor_for_current_height;
+      }
+    };
+
+    extern bed_leveling blm;
+    extern int Unified_Bed_Leveling_EEPROM_start;
+
+#endif // AUTO_BED_LEVELING_UBL
+#endif // UNIFIED_BED_LEVELING_H
\ No newline at end of file
diff --git a/Marlin/UBL_Bed_Leveling.cpp b/Marlin/UBL_Bed_Leveling.cpp
new file mode 100644
index 0000000000..feff74e976
--- /dev/null
+++ b/Marlin/UBL_Bed_Leveling.cpp
@@ -0,0 +1,296 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (C) 2016 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * 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/>.
+ *
+ */
+
+#include "Marlin.h"
+#include "math.h"
+
+#if ENABLED(AUTO_BED_LEVELING_UBL)
+  #include "UBL.h"
+  #include "hex_print_routines.h"
+
+  /**
+   * These variables used to be declared inside the bed_leveling class.  We are going to still declare
+   * them within the .cpp file for bed leveling.   But there is only one instance of the bed leveling
+   * object and we can get rid of a level of inderection by not making them 'member data'.  So, in the
+   * interest of speed, we do it this way.    When we move to a 32-Bit processor, they can be moved
+   * back inside the bed leveling class.
+   */
+  float last_specified_z,
+        fade_scaling_factor_for_current_height,
+        z_values[UBL_MESH_NUM_X_POINTS][UBL_MESH_NUM_Y_POINTS],
+        mesh_index_to_X_location[UBL_MESH_NUM_X_POINTS + 1], // +1 just because of paranoia that we might end up on the
+        mesh_index_to_Y_location[UBL_MESH_NUM_Y_POINTS + 1]; // the last Mesh Line and that is the start of a whole new cell
+
+  bed_leveling::bed_leveling() {
+    for (uint8_t i = 0; i <= UBL_MESH_NUM_X_POINTS; i++)  // We go one past what we expect to ever need for safety
+      mesh_index_to_X_location[i] = double(UBL_MESH_MIN_X) + double(MESH_X_DIST) * double(i);
+
+    for (uint8_t i = 0; i <= UBL_MESH_NUM_Y_POINTS; i++)  // We go one past what we expect to ever need for safety
+      mesh_index_to_Y_location[i] = double(UBL_MESH_MIN_Y) + double(MESH_Y_DIST) * double(i);
+
+    reset();
+  }
+
+  void bed_leveling::store_state() {
+    int k = E2END - sizeof(blm.state);
+    eeprom_write_block((void *)&blm.state, (void *)k, sizeof(blm.state));
+  }
+
+  void bed_leveling::load_state() {
+    int k = E2END - sizeof(blm.state);
+    eeprom_read_block((void *)&blm.state, (void *)k, sizeof(blm.state));
+
+    if (sanity_check())
+      SERIAL_PROTOCOLLNPGM("?In load_state() sanity_check() failed.\n");
+
+    // These lines can go away in a few weeks.  They are just
+    // to make sure people updating thier firmware won't be using
+    if (blm.state.G29_Fade_Height_Multiplier != 1.0 / blm.state.G29_Correction_Fade_Height) { // an incomplete Bed_Leveling.state structure. For speed
+      blm.state.G29_Fade_Height_Multiplier = 1.0 / blm.state.G29_Correction_Fade_Height;      // we now multiply by the inverse of the Fade Height instead of
+      store_state();   // dividing by it. Soon... all of the old structures will be
+    }                  // updated, but until then, we try to ease the transition
+                       // for our Beta testers.
+  }
+
+  void bed_leveling::load_mesh(int m) {
+    int k = E2END - sizeof(blm.state),
+        j = (k - Unified_Bed_Leveling_EEPROM_start) / sizeof(z_values);
+
+    if (m == -1) {
+      SERIAL_PROTOCOLLNPGM("?No mesh saved in EEPROM. Zeroing mesh in memory.\n");
+      reset();
+      return;
+    }
+
+    if (m < 0 || m >= j || Unified_Bed_Leveling_EEPROM_start <= 0) {
+      SERIAL_PROTOCOLLNPGM("?EEPROM storage not available to load mesh.\n");
+      return;
+    }
+
+    j = k - (m + 1) * sizeof(z_values);
+    eeprom_read_block((void *)&z_values , (void *)j, sizeof(z_values));
+
+    SERIAL_PROTOCOLPGM("Mesh loaded from slot ");
+    SERIAL_PROTOCOL(m);
+    SERIAL_PROTOCOLPGM("  at offset 0x");
+    prt_hex_word(j);
+    SERIAL_EOL;
+  }
+
+  void bed_leveling:: store_mesh(int m) {
+    int k = E2END - sizeof(state),
+        j = (k - Unified_Bed_Leveling_EEPROM_start) / sizeof(z_values);
+
+    if (m < 0 || m >= j || Unified_Bed_Leveling_EEPROM_start <= 0) {
+      SERIAL_PROTOCOLLNPGM("?EEPROM storage not available to load mesh.\n");
+      SERIAL_PROTOCOL(m);
+      SERIAL_PROTOCOLLNPGM(" mesh slots available.\n");
+      SERIAL_PROTOCOLLNPAIR("E2END     : ", E2END);
+      SERIAL_PROTOCOLLNPAIR("k         : ", k);
+      SERIAL_PROTOCOLLNPAIR("j         : ", j);
+      SERIAL_PROTOCOLLNPAIR("m         : ", m);
+      SERIAL_EOL;
+      return;
+    }
+
+    j = k - (m + 1) * sizeof(z_values);
+    eeprom_write_block((const void *)&z_values, (void *)j, sizeof(z_values));
+
+    SERIAL_PROTOCOLPGM("Mesh saved in slot ");
+    SERIAL_PROTOCOL(m);
+    SERIAL_PROTOCOLPGM("  at offset 0x");
+    prt_hex_word(j);
+    SERIAL_EOL;
+  }
+
+  void bed_leveling::reset() {
+    state.active = false;
+    state.z_offset = 0;
+    state.EEPROM_storage_slot = -1;
+
+    ZERO(z_values);
+
+    last_specified_z = -999.9;        // We can't pre-initialize these values in the declaration
+    fade_scaling_factor_for_current_height = 0.0; // due to C++11 constraints
+  }
+
+  void bed_leveling::invalidate() {
+    prt_hex_word((unsigned int)this);
+    SERIAL_EOL;
+
+    state.active = false;
+    state.z_offset = 0;
+    for (int x = 0; x < UBL_MESH_NUM_X_POINTS; x++)
+      for (int y = 0; y < UBL_MESH_NUM_Y_POINTS; y++)
+        z_values[x][y] = NAN;
+  }
+
+  void bed_leveling::display_map(int map_type) {
+    float f, current_xi, current_yi;
+    int8_t i, j;
+    UNUSED(map_type);
+
+    SERIAL_PROTOCOLLNPGM("\nBed Topography Report:\n");
+
+    SERIAL_ECHOPAIR("(", 0);
+    SERIAL_ECHOPAIR(", ", UBL_MESH_NUM_Y_POINTS - 1);
+    SERIAL_ECHOPGM(")    ");
+
+    current_xi = blm.get_cell_index_x(current_position[X_AXIS] + (MESH_X_DIST) / 2.0);
+    current_yi = blm.get_cell_index_y(current_position[Y_AXIS] + (MESH_Y_DIST) / 2.0);
+
+    for (i = 0; i < UBL_MESH_NUM_X_POINTS - 1; i++)
+      SERIAL_ECHOPGM("                 ");
+
+    SERIAL_ECHOPAIR("(", UBL_MESH_NUM_X_POINTS - 1);
+    SERIAL_ECHOPAIR(",", UBL_MESH_NUM_Y_POINTS - 1);
+    SERIAL_ECHOLNPGM(")");
+
+    //  if (map_type || 1) {
+    SERIAL_ECHOPAIR("(", UBL_MESH_MIN_X);
+    SERIAL_ECHOPAIR(",", UBL_MESH_MAX_Y);
+    SERIAL_CHAR(')');
+
+    for (i = 0; i < UBL_MESH_NUM_X_POINTS - 1; i++)
+      SERIAL_ECHOPGM("                 ");
+
+    SERIAL_ECHOPAIR("(", UBL_MESH_MAX_X);
+    SERIAL_ECHOPAIR(",", UBL_MESH_MAX_Y);
+    SERIAL_ECHOLNPGM(")");
+    //  }
+
+    for (j = UBL_MESH_NUM_Y_POINTS - 1; j >= 0; j--) {
+      for (i = 0; i < UBL_MESH_NUM_X_POINTS; i++) {
+        f = z_values[i][j];
+
+        // is the nozzle here?  if so, mark the number
+        SERIAL_CHAR(i == current_xi && j == current_yi ? '[' : ' ');
+
+        if (isnan(f))
+          SERIAL_PROTOCOLPGM("      .       ");
+        else {
+          // if we don't do this, the columns won't line up nicely
+          if (f >= 0.0) SERIAL_CHAR(' ');
+          SERIAL_PROTOCOL_F(f, 5);
+          idle();
+        }
+        if (i == current_xi && j == current_yi) // is the nozzle here? if so, finish marking the number
+          SERIAL_CHAR(']');
+        else
+          SERIAL_PROTOCOL("  ");
+
+        SERIAL_CHAR(' ');
+      }
+      SERIAL_EOL;
+      if (j) { // we want the (0,0) up tight against the block of numbers
+        SERIAL_CHAR(' ');
+        SERIAL_EOL;
+      }
+    }
+
+    //  if (map_type) {
+    SERIAL_ECHOPAIR("(", int(UBL_MESH_MIN_X));
+    SERIAL_ECHOPAIR(",", int(UBL_MESH_MIN_Y));
+    SERIAL_ECHOPGM(")    ");
+
+    for (i = 0; i < UBL_MESH_NUM_X_POINTS - 1; i++)
+      SERIAL_ECHOPGM("                 ");
+
+    SERIAL_ECHOPAIR("(", int(UBL_MESH_MAX_X));
+    SERIAL_ECHOPAIR(",", int(UBL_MESH_MIN_Y));
+    SERIAL_CHAR(')');
+    //  }
+
+    SERIAL_ECHOPAIR("(", 0);
+    SERIAL_ECHOPAIR(",", 0);
+    SERIAL_ECHOPGM(")       ");
+
+    for (i = 0; i < UBL_MESH_NUM_X_POINTS - 1; i++)
+      SERIAL_ECHOPGM("                 ");
+
+    SERIAL_ECHOPAIR("(", UBL_MESH_NUM_X_POINTS-1);
+    SERIAL_ECHOPAIR(",", 0);
+    SERIAL_CHAR(')');
+
+    SERIAL_CHAR(' ');
+    SERIAL_EOL;
+  }
+
+  bool bed_leveling::sanity_check() {
+    uint8_t error_flag = 0;
+
+    if (state.n_x !=  UBL_MESH_NUM_X_POINTS)  {
+      SERIAL_PROTOCOLLNPGM("?UBL_MESH_NUM_X_POINTS set wrong\n");
+      error_flag++;
+    }
+
+    if (state.n_y !=  UBL_MESH_NUM_Y_POINTS)  {
+      SERIAL_PROTOCOLLNPGM("?UBL_MESH_NUM_Y_POINTS set wrong\n");
+      error_flag++;
+    }
+
+    if (state.mesh_x_min !=  UBL_MESH_MIN_X)  {
+      SERIAL_PROTOCOLLNPGM("?UBL_MESH_MIN_X set wrong\n");
+      error_flag++;
+    }
+
+    if (state.mesh_y_min !=  UBL_MESH_MIN_Y)  {
+      SERIAL_PROTOCOLLNPGM("?UBL_MESH_MIN_Y set wrong\n");
+      error_flag++;
+    }
+
+    if (state.mesh_x_max !=  UBL_MESH_MAX_X)  {
+      SERIAL_PROTOCOLLNPGM("?UBL_MESH_MAX_X set wrong\n");
+      error_flag++;
+    }
+
+    if (state.mesh_y_max !=  UBL_MESH_MAX_Y)  {
+      SERIAL_PROTOCOLLNPGM("?UBL_MESH_MAX_Y set wrong\n");
+      error_flag++;
+    }
+
+    if (state.mesh_x_dist !=  MESH_X_DIST)  {
+      SERIAL_PROTOCOLLNPGM("?MESH_X_DIST set wrong\n");
+      error_flag++;
+    }
+
+    if (state.mesh_y_dist !=  MESH_Y_DIST)  {
+      SERIAL_PROTOCOLLNPGM("?MESH_Y_DIST set wrong\n");
+      error_flag++;
+    }
+
+    int k = E2END - sizeof(blm.state),
+        j = (k - Unified_Bed_Leveling_EEPROM_start) / sizeof(z_values);
+
+    if (j < 1) {
+      SERIAL_PROTOCOLLNPGM("?No EEPROM storage available for a mesh of this size.\n");
+      error_flag++;
+    }
+
+    //  SERIAL_PROTOCOLPGM("?sanity_check() return value: ");
+    //  SERIAL_PROTOCOL(error_flag);
+    //  SERIAL_EOL;
+
+    return !!error_flag;
+  }
+
+#endif // AUTO_BED_LEVELING_UBL
diff --git a/Marlin/UBL_G29.cpp b/Marlin/UBL_G29.cpp
new file mode 100644
index 0000000000..7f4bdf3686
--- /dev/null
+++ b/Marlin/UBL_G29.cpp
@@ -0,0 +1,1455 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (C) 2016 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * 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/>.
+ *
+ */
+
+#include "Marlin.h"
+#if ENABLED(AUTO_BED_LEVELING_UBL)
+  //#include "vector_3.h"
+  //#include "qr_solve.h"
+
+  #include "UBL.h"
+  #include "hex_print_routines.h"
+  #include "configuration_store.h"
+  #include "planner.h"
+  #include "ultralcd.h"
+
+  #include <avr/io.h>
+
+  void lcd_babystep_z();
+  void lcd_return_to_status();
+  bool lcd_clicked();
+  void lcd_implementation_clear();
+  void lcd_mesh_edit_setup(float inital);
+  float lcd_mesh_edit();
+  void lcd_z_offset_edit_setup(float);
+  float lcd_z_offset_edit();
+
+  extern float meshedit_done;
+  extern long babysteps_done;
+  extern float code_value_float();
+  extern bool code_value_bool();
+  extern bool code_has_value();
+  extern float probe_pt(float x, float y, bool, int);
+  extern float zprobe_zoffset;
+  extern bool set_probe_deployed(bool);
+  #define DEPLOY_PROBE() set_probe_deployed(true)
+  #define STOW_PROBE() set_probe_deployed(false)
+  bool ProbeStay = true;
+  float ubl_3_point_1_X = UBL_PROBE_PT_1_X;
+  float ubl_3_point_1_Y = UBL_PROBE_PT_1_Y;
+  float ubl_3_point_2_X = UBL_PROBE_PT_2_X;
+  float ubl_3_point_2_Y = UBL_PROBE_PT_2_Y;
+  float ubl_3_point_3_X = UBL_PROBE_PT_3_X;
+  float ubl_3_point_3_Y = UBL_PROBE_PT_3_Y;
+
+  #define SIZE_OF_LITTLE_RAISE 0
+  #define BIG_RAISE_NOT_NEEDED 0
+  extern void lcd_quick_feedback();
+
+  /**
+   * G29: Unified Bed Leveling by Roxy
+   */
+
+  // Transform required to compensate for bed level
+  //extern matrix_3x3 plan_bed_level_matrix;
+
+  /**
+   *   Get the position applying the bed level matrix
+   */
+
+  //vector_3 plan_get_position();
+
+  // static void set_bed_level_equation_lsq(double* plane_equation_coefficients);
+  // static void set_bed_level_equation_3pts(float z_at_pt_1, float z_at_pt_2, float z_at_pt_3);
+
+  /**
+   *   G29: Mesh Based Compensation System
+   *
+   *   Parameters understood by this leveling system:
+   *
+   *   A     Activate  Activate the Unified Bed Leveling system.
+   *
+   *   B #   Business  Use the 'Business Card' mode of the Manual Probe subsystem.  This is invoked as
+   *   G29 P2 B   The mode of G29 P2 allows you to use a bussiness card or recipe card
+   *   as a shim that the nozzle will pinch as it is lowered. The idea is that you
+   *   can easily feel the nozzle getting to the same height by the amount of resistance
+   *   the business card exhibits to movement. You should try to achieve the same amount
+   *   of resistance on each probed point to facilitate accurate and repeatable measurements.
+   *   You should be very careful not to drive the nozzle into the bussiness card with a
+   *   lot of force as it is very possible to cause damage to your printer if your are
+   *   careless.  If you use the B option with G29 P2 B you can leave the number parameter off
+   *   on its first use to enable measurement of the business card thickness.  Subsequent usage
+   *   of the B parameter can have the number previously measured supplied to the command.
+   *   Incidently, you are much better off using something like a Spark Gap feeler gauge than
+   *   something that compresses like a Business Card.
+   *
+   *   C     Continue  Continue, Constant, Current Location. This is not a primary command.  C is used to
+   *   further refine the behaviour of several other commands.  Issuing a G29 P1 C will
+   *   continue the generation of a partially constructed Mesh without invalidating what has
+   *   been done.  Issuing a G29 P2 C will tell the Manual Probe subsystem to use the current
+   *   location in its search for the closest unmeasured Mesh Point.  When used with a G29 Z C
+   *   it indicates to use the current location instead of defaulting to the center of the print bed.
+   *
+   *   D     Disable   Disable the Unified Bed Leveling system.
+   *
+   *   E     Stow_probe Stow the probe after each sampled point.
+   *
+   *   F #   Fade   *   Fade the amount of Mesh Based Compensation over a specified height.  At the specified height,
+   *   no correction is applied and natural printer kenimatics take over.  If no number is specified
+   *   for the command, 10mm is assummed to be reasonable.
+   *
+   *   G #   Grid   *   Perform a Grid Based Leveling of the current Mesh using a grid with n points on
+   *   a side.
+   *
+   *   H #   Height    Specify the Height to raise the nozzle after each manual probe of the bed.  The
+   *   default is 5mm.
+   *
+   *   I #   Invalidate Invalidate specified number of Mesh Points.  The nozzle location is used unless
+   *   the X and Y parameter are used. If no number is specified, only the closest Mesh
+   *   point to the location is invalidated.  The M parameter is available as well to produce
+   *   a map after the operation.  This command is useful to invalidate a portion of the
+   *   Mesh so it can be adjusted using other tools in the Unified Bed Leveling System.  When
+   *   attempting to invalidate an isolated bad point in the mesh, the M option will indicate
+   *   where the nozzle is positioned in the Mesh with (#).  You can move the nozzle around on
+   *   the bed and use this feature to select the center of the area (or cell) you want to
+   *   invalidate.
+   *
+   *   K #   Kompare   Kompare current Mesh with stored Mesh # replacing current Mesh with the result.  This
+   *   command litterly performs a difference between two Mesh.
+   *
+   *   L     Load   *   Load Mesh from the previously activated location in the EEPROM.
+   *
+   *   L #   Load   *   Load Mesh from the specified location in the EEPROM.  Set this location as activated
+   *   for subsequent Load and Store operations.
+   *
+   *   O     Map   *    Display the Mesh Map Topology.
+   *   The parameter can be specified alone (ie. G29 O) or in combination with many of the
+   *   other commands.  The Mesh Map option works with all of the Phase
+   *   commands (ie. G29 P4 R 5 X 50 Y100 C -.1 O)
+   *
+   *   N    No Home    G29 normally insists that a G28 has been performed.  You can over rule this with an
+   *   N option.  In general, you should not do this.  This can only be done safely with
+   *   commands that do not move the nozzle.
+   *
+   *   The P or Phase commands are used for the bulk of the work to setup a Mesh.  In general, your Mesh will
+   *   start off being initialized with a G29 P0 or a G29 P1. Further refinement of the Mesh happens with
+   *   each additional Phase that processes it.
+   *
+   *   P0    Phase 0   Zero Mesh Data and turn off the Mesh Compensation System.  This reverts the
+   *   3D Printer to the same state it was in before the Unified Bed Leveling Compensation
+   *   was turned on.  Setting the entire Mesh to Zero is a special case that allows
+   *   a subsequent G or T leveling operation for backward compatability.
+   *
+   *   P1    Phase 1   Invalidate entire Mesh and continue with automatic generation of the Mesh data using
+   *   the Z-Probe. Depending upon the values of DELTA_PROBEABLE_RADIUS and
+   *   DELTA_PRINTABLE_RADIUS some area of the bed will not have Mesh Data automatically
+   *   generated.  This will be handled in Phase 2.  If the Phase 1 command is given the
+   *   C (Continue) parameter it does not invalidate the Mesh prior to automatically
+   *   probing needed locations.  This allows you to invalidate portions of the Mesh but still
+   *   use the automatic probing capabilities of the Unified Bed Leveling System.  An X and Y
+   *   parameter can be given to prioritize where the command should be trying to measure points.
+   *   If the X and Y parameters are not specified the current probe position is used.  Phase 1
+   *   allows you to specify the M (Map) parameter so you can watch the generation of the Mesh.
+   *   Phase 1 also watches for the LCD Panel's Encoder Switch being held in a depressed state.
+   *   It will suspend generation of the Mesh if it sees the user request that.  (This check is
+   *   only done between probe points.  You will need to press and hold the switch until the
+   *   Phase 1 command can detect it.)
+   *
+   *   P2    Phase 2   Probe areas of the Mesh that can not be automatically handled.  Phase 2 respects an H
+   *   parameter to control the height between Mesh points.  The default height for movement
+   *   between Mesh points is 5mm.  A smaller number can be used to make this part of the
+   *   calibration less time consuming.  You will be running the nozzle down until it just barely
+   *   touches the glass.  You should have the nozzle clean with no plastic obstructing your view.
+   *   Use caution and move slowly.  It is possible to damage your printer if you are careless.
+   *   Note that this command will use the configuration #define SIZE_OF_LITTLE_RAISE if the
+   *   nozzle is moving a distance of less than BIG_RAISE_NOT_NEEDED.
+   *
+   *   The H parameter can be set negative if your Mesh dips in a large area.  You can press
+   *   and hold the LCD Panel's encoder wheel to terminate the current Phase 2 command.  You
+   *   can then re-issue the G29 P 2 command with an H parameter that is more suitable for the
+   *   area you are manually probing.  Note that the command tries to start you in a corner
+   *   of the bed where movement will be predictable.  You can force the location to be used in
+   *   the distance calculations by using the X and Y parameters.  You may find it is helpful to
+   *   print out a Mesh Map (G29 O ) to understand where the mesh is invalidated and where
+   *   the nozzle will need to move in order to complete the command.   The C parameter is
+   *   available on the Phase 2 command also and indicates the search for points to measure should
+   *   be done based on the current location of the nozzle.
+   *
+   *   A B parameter is also available for this command and described up above.  It places the
+   *   manual probe subsystem into Business Card mode where the thickness of a business care is
+   *   measured and then used to accurately set the nozzle height in all manual probing for the
+   *   duration of the command.  (S for Shim mode would be a better parameter name, but S is needed
+   *   for Save or Store of the Mesh to EEPROM)  A Business card can be used, but you will have
+   *   better results if you use a flexible Shim that does not compress very much.  That makes it
+   *   easier for you to get the nozzle to press with similar amounts of force against the shim so you
+   *   can get accurate measurements.  As you are starting to touch the nozzle against the shim try
+   *   to get it to grasp the shim with the same force as when you measured the thickness of the
+   *   shim at the start of the command.
+   *
+   *   Phase 2 allows the O (Map) parameter to be specified.  This helps the user see the progression
+   *   of the Mesh being built.
+   *
+   *   P3    Phase 3   Fill the unpopulated regions of the Mesh with a fixed value.  The C parameter is used to
+   *   specify the Constant value to fill all invalid areas of the Mesh.  If no C parameter is
+   *   specified, a value of 0.0 is assumed.  The R parameter can be given to specify the number
+   *   of points to set.  If the R parameter is specified the current nozzle position is used to
+   *   find the closest points to alter unless the X and Y parameter are used to specify the fill
+   *   location.
+   *
+   *   P4    Phase 4   Fine tune the Mesh.  The Delta Mesh Compensation System assume the existance of
+   *   an LCD Panel.  It is possible to fine tune the mesh without the use of an LCD Panel.
+   *   (More work and details on doing this later!)
+   *   The System will search for the closest Mesh Point to the nozzle.  It will move the
+   *   nozzle to this location.  The user can use the LCD Panel to carefully adjust the nozzle
+   *   so it is just barely touching the bed.  When the user clicks the control, the System
+   *   will lock in that height for that point in the Mesh Compensation System.
+   *
+   *   Phase 4 has several additional parameters that the user may find helpful.  Phase 4
+   *   can be started at a specific location by specifying an X and Y parameter.  Phase 4
+   *   can be requested to continue the adjustment of Mesh Points by using the R(epeat)
+   *   parameter.  If the Repetition count is not specified, it is assumed the user wishes
+   *   to adjust the entire matrix.  The nozzle is moved to the Mesh Point being edited.
+   *   The command can be terminated early (or after the area of interest has been edited) by
+   *   pressing and holding the encoder wheel until the system recognizes the exit request.
+   *   Phase 4's general form is G29 P4 [R # of points] [X position] [Y position]
+   *
+   *   Phase 4 is intended to be used with the G26 Mesh Validation Command.  Using the
+   *   information left on the printer's bed from the G26 command it is very straight forward
+   *   and easy to fine tune the Mesh.  One concept that is important to remember and that
+   *   will make using the Phase 4 command easy to use is this:  You are editing the Mesh Points.
+   *   If you have too little clearance and not much plastic was extruded in an area, you want to
+   *   LOWER the Mesh Point at the location.  If you did not get good adheasion, you want to
+   *   RAISE the Mesh Point at that location.
+   *
+   *
+   *   P5    Phase 5   Find Mean Mesh Height and Standard Deviation.  Typically, it is easier to use and
+   *   work with the Mesh if it is Mean Adjusted.  You can specify a C parameter to
+   *   Correct the Mesh to a 0.00 Mean Height.  Adding a C parameter will automatically
+   *   execute a G29 P6 C <mean height>.
+   *
+   *   P6    Phase 6   Shift Mesh height.  The entire Mesh's height is adjusted by the height specified
+   *   with the C parameter.  Being able to adjust the height of a Mesh is useful tool.  It
+   *   can be used to compensate for poorly calibrated Z-Probes and other errors.  Ideally,
+   *   you should have the Mesh adjusted for a Mean Height of 0.00 and the Z-Probe measuring
+   *   0.000 at the Z Home location.
+   *
+   *   Q     Test   *   Load specified Test Pattern to assist in checking correct operation of system.  This
+   *   command is not anticipated to be of much value to the typical user.  It is intended
+   *   for developers to help them verify correct operation of the Unified Bed Leveling System.
+   *
+   *   S     Store     Store the current Mesh in the Activated area of the EEPROM.  It will also store the
+   *   current state of the Unified Bed Leveling system in the EEPROM.
+   *
+   *   S #   Store     Store the current Mesh at the specified location in EEPROM.  Activate this location
+   *   for subsequent Load and Store operations.  It will also store the current state of
+   *   the Unified Bed Leveling system in the EEPROM.
+   *
+   *   S -1  Store     Store the current Mesh as a print out that is suitable to be feed back into
+   *   the system at a later date. The text generated can be saved and later sent by PronterFace or
+   *   Repetier Host to reconstruct the current mesh on another machine.
+   *
+   *   T     3-Point   Perform a 3 Point Bed Leveling on the current Mesh
+   *
+   *   W     What?     Display valuable data the Unified Bed Leveling System knows.
+   *
+   *   X #   *      *    Specify X Location for this line of commands
+   *
+   *   Y #   *      *    Specify Y Location for this line of commands
+   *
+   *   Z     Zero   *   Probes to set the Z Height of the nozzle.  The entire Mesh can be raised or lowered
+   *   by just doing a G29 Z
+   *
+   *   Z #   Zero   *   The entire Mesh can be raised or lowered to conform with the specified difference.
+   *   zprobe_zoffset is added to the calculation.
+   *
+   *
+   *   Release Notes:
+   *   You MUST do a M502 & M500 pair of commands to initialize the storage.  Failure to do this
+   *   will cause all kinds of problems.  Enabling EEPROM Storage is highly recommended.  With
+   *   EEPROM Storage of the mesh, you are limited to 3-Point and Grid Leveling.  (G29 P0 T and
+   *   G29 P0 G respectively.)
+   *
+   *   Z-Probe Sleds are not currently fully supported.  There were too many complications caused
+   *   by them to support them in the Unified Bed Leveling code.  Support for them will be handled
+   *   better in the upcoming Z-Probe Object that will happen during the Code Clean Up phase.  (That
+   *   is what they really are:  A special case of the Z-Probe.)  When a Z-Probe Object appears, it
+   *   should slip in under the Unified Bed Leveling code without major trauma.
+   *
+   *   When you do a G28 and then a G29 P1 to automatically build your first mesh, you are going to notice
+   *   the Unified Bed Leveling probes points further and further away from the starting location. (The
+   *   starting location defaults to the center of the bed.)   The original Grid and Mesh leveling used
+   *   a Zig Zag pattern. The new pattern is better, especially for people with Delta printers.  This
+   *   allows you to get the center area of the Mesh populated (and edited) quicker.  This allows you to
+   *   perform a small print and check out your settings quicker.  You do not need to populate the
+   *   entire mesh to use it.  (You don't want to spend a lot of time generating a mesh only to realize
+   *   you don't have the resolution or zprobe_zoffset set correctly.  The Mesh generation
+   *   gathers points closest to where the nozzle is located unless you specify an (X,Y) coordinate pair.
+   *
+   *   The Unified Bed Leveling uses a lot of EEPROM storage to hold its data.  And it takes some effort
+   *   to get this Mesh data correct for a user's printer.  We do not want this data destroyed as
+   *   new versions of Marlin add or subtract to the items stored in EEPROM.  So, for the benefit of
+   *   the users, we store the Mesh data at the end of the EEPROM and do not keep it contiguous with the
+   *   other data stored in the EEPROM.  (For sure the developers are going to complain about this, but
+   *   this is going to be helpful to the users!)
+   *
+   *   The foundation of this Bed Leveling System is built on Epatel's Mesh Bed Leveling code.  A big
+   *   'Thanks!' to him and the creators of 3-Point and Grid Based leveling.  Combining thier contributions
+   *   we now have the functionality and features of all three systems combined.
+   */
+
+  int Unified_Bed_Leveling_EEPROM_start = -1;
+  int UBL_has_control_of_LCD_Panel = 0;
+  volatile int G29_encoderDiff = 0; // This is volatile because it is getting changed at interrupt time.
+
+  // We keep the simple parameter flags and values as 'static' because we break out the
+  // parameter parsing into a support routine.
+
+  static int G29_Verbose_Level = 0, Test_Value = 0,
+             Phase_Value = -1, Repetition_Cnt = 1;
+  static bool Repeat_Flag = UBL_OK, C_Flag = false, X_Flag = UBL_OK, Y_Flag = UBL_OK, Statistics_Flag = UBL_OK, Business_Card_Mode = false;
+  static float X_Pos = 0.0, Y_Pos = 0.0, Height_Value = 5.0, measured_z, card_thickness = 0.0, Constant = 0.0;
+  static int Storage_Slot = 0, Test_Pattern = 0;
+
+  #if ENABLED(ULTRA_LCD)
+    void lcd_setstatus(const char* message, bool persist);
+  #endif
+
+  void gcode_G29() {
+    mesh_index_pair location;
+    int i, j, k;
+    float Z1, Z2, Z3;
+
+    G29_Verbose_Level = 0;  // These may change, but let's get some reasonable values into them.
+    Repeat_Flag       = UBL_OK;
+    Repetition_Cnt    = 1;
+    C_Flag            = false;
+
+    SERIAL_PROTOCOLPGM("Unified_Bed_Leveling_EEPROM_start=");
+    SERIAL_PROTOCOLLN(Unified_Bed_Leveling_EEPROM_start);
+
+    if (Unified_Bed_Leveling_EEPROM_start < 0) {
+      SERIAL_PROTOCOLLNPGM("?You need to enable your EEPROM and initialize it ");
+      SERIAL_PROTOCOLLNPGM("with M502, M500, M501 in that order.\n");
+      return;
+    }
+
+    if (!code_seen('N') && axis_unhomed_error(true, true, true))  // Don't allow auto-leveling without homing first
+      gcode_G28();
+
+    if (G29_Parameter_Parsing()) return; // abort if parsing the simple parameters causes a problem,
+
+    // Invalidate Mesh Points. This command is a little bit asymetrical because
+    // it directly specifies the repetition count and does not use the 'R' parameter.
+    if (code_seen('I')) {
+      Repetition_Cnt = code_has_value() ? code_value_int() : 1;
+      while (Repetition_Cnt--) {
+        location = find_closest_mesh_point_of_type(REAL, X_Pos, Y_Pos, 0, NULL);  // The '0' says we want to use the nozzle's position
+        if (location.x_index < 0) {
+          SERIAL_PROTOCOLLNPGM("Entire Mesh invalidated.\n");
+          break;            // No more invalid Mesh Points to populate
+        }
+        z_values[location.x_index][location.y_index] = NAN;
+      }
+      SERIAL_PROTOCOLLNPGM("Locations invalidated.\n");
+    }
+
+    if (code_seen('Q')) {
+
+      if (code_has_value()) Test_Pattern = code_value_int();
+
+      if (Test_Pattern < 0 || Test_Pattern > 4) {
+        SERIAL_PROTOCOLLNPGM("Invalid Test_Pattern value. (0-4)\n");
+        return;
+      }
+      SERIAL_PROTOCOLLNPGM("Loading Test_Pattern values.\n");
+      switch (Test_Pattern) {
+        case 0:
+          for (i = 0; i < UBL_MESH_NUM_X_POINTS; i++) {         // Create a bowl shape. This is
+            for (j = 0; j < UBL_MESH_NUM_Y_POINTS; j++) {       // similar to what a user would see with
+              Z1 = 0.5 * (UBL_MESH_NUM_X_POINTS) - i;  // a poorly calibrated Delta.
+              Z2 = 0.5 * (UBL_MESH_NUM_Y_POINTS) - j;
+              z_values[i][j] += 2.0 * HYPOT(Z1, Z2);
+            }
+          }
+        break;
+        case 1:
+          for (i = 0; i < UBL_MESH_NUM_X_POINTS; i++) {         // Create a diagonal line several Mesh
+            z_values[i][i] += 9.999;                             // cells thick that is raised
+            if (i < UBL_MESH_NUM_Y_POINTS - 1)
+              z_values[i][i + 1] += 9.999;                       // We want the altered line several mesh points thick
+            if (i > 0)
+              z_values[i][i - 1] += 9.999;                       // We want the altered line several mesh points thick
+          }
+          break;
+        case 2:
+          // Allow the user to specify the height because 10mm is
+          // a little bit extreme in some cases.
+          for (i = (UBL_MESH_NUM_X_POINTS) / 3.0; i < 2 * ((UBL_MESH_NUM_X_POINTS) / 3.0); i++)   // Create a rectangular raised area in
+            for (j = (UBL_MESH_NUM_Y_POINTS) / 3.0; j < 2 * ((UBL_MESH_NUM_Y_POINTS) / 3.0); j++) // the center of the bed
+              z_values[i][j] += code_seen('C') ? Constant : 9.99;
+          break;
+        case 3:
+          break;
+      }
+    }
+
+    if (code_seen('P')) {
+      Phase_Value = code_value_int();
+      if (Phase_Value < 0 || Phase_Value > 7) {
+        SERIAL_PROTOCOLLNPGM("Invalid Phase value. (0-4)\n");
+        return;
+      }
+      switch (Phase_Value) {
+        //
+        // Zero Mesh Data
+        //
+        case 0:
+          blm.reset();
+          SERIAL_PROTOCOLLNPGM("Mesh zeroed.\n");
+          break;
+        //
+        // Invalidate Entire Mesh and Automatically Probe Mesh in areas that can be reached by the probe
+        //
+        case 1:
+          if (!code_seen('C') )  {
+            blm.invalidate();
+            SERIAL_PROTOCOLLNPGM("Mesh invalidated. Probing mesh.\n");
+          }
+          if (G29_Verbose_Level > 1) {
+            SERIAL_ECHOPGM("Probing Mesh Points Closest to (");
+            SERIAL_ECHO(X_Pos);
+            SERIAL_ECHOPAIR(",", Y_Pos);
+            SERIAL_PROTOCOLLNPGM(")\n");
+          }
+          probe_entire_mesh( X_Pos+X_PROBE_OFFSET_FROM_EXTRUDER, Y_Pos+Y_PROBE_OFFSET_FROM_EXTRUDER,
+                             code_seen('O') || code_seen('M'), code_seen('E'));
+          break;
+        //
+        // Manually Probe Mesh in areas that can not be reached by the probe
+        //
+        case 2:
+          SERIAL_PROTOCOLLNPGM("Manually probing unreachable mesh locations.\n");
+          do_blocking_move_to_z(Z_CLEARANCE_BETWEEN_PROBES);
+          if (!X_Flag && !Y_Flag) {      // use a good default location for the path
+            X_Pos = X_MIN_POS;
+            Y_Pos = Y_MIN_POS;
+            if (X_PROBE_OFFSET_FROM_EXTRUDER > 0)   // The flipped > and < operators on these two comparisons is
+              X_Pos = X_MAX_POS;                    // intentional. It should cause the probed points to follow a
+
+            if (Y_PROBE_OFFSET_FROM_EXTRUDER < 0)   // nice path on Cartesian printers. It may make sense to
+              Y_Pos = Y_MAX_POS;                    // have Delta printers default to the center of the bed.
+
+          }           // For now, until that is decided, it can be forced with the X
+                      // and Y parameters.
+          if (code_seen('C')) {
+            X_Pos = current_position[X_AXIS];
+            Y_Pos = current_position[Y_AXIS];
+          }
+
+          Height_Value = code_seen('H') && code_has_value() ? code_value_float() : Z_CLEARANCE_BETWEEN_PROBES;
+
+          if ((Business_Card_Mode = code_seen('B'))) {
+            card_thickness = code_has_value() ? code_value_float() : measure_business_card_thickness(Height_Value);
+
+            if (fabs(card_thickness) > 1.5)  {
+              SERIAL_PROTOCOLLNPGM("?Error in Business Card measurment.\n");
+              return;
+            }
+          }
+          manually_probe_remaining_mesh( X_Pos, Y_Pos, Height_Value, card_thickness, code_seen('O') || code_seen('M'));
+          break;
+        //
+        // Populate invalid Mesh areas with a constant
+        //
+        case 3:
+          Height_Value = 0.0; // Assume 0.0 until proven otherwise
+          if (code_seen('C')) Height_Value = Constant;
+          // If no repetition is specified, do the whole Mesh
+          if (!Repeat_Flag) Repetition_Cnt = 9999;
+          while (Repetition_Cnt--) {
+            location = find_closest_mesh_point_of_type( INVALID, X_Pos, Y_Pos, 0, NULL); // The '0' says we want to use the nozzle's position
+            if (location.x_index < 0) break; // No more invalid Mesh Points to populate
+            z_values[location.x_index][location.y_index] = Height_Value;
+          }
+          break;
+        //
+        // Fine Tune (Or Edit) the Mesh
+        //
+        case 4:
+          fine_tune_mesh(X_Pos, Y_Pos, Height_Value, code_seen('O') || code_seen('M'));
+          break;
+        case 5:
+          Find_Mean_Mesh_Height();
+          break;
+        case 6:
+          Shift_Mesh_Height();
+          break;
+
+        case 10:
+          UBL_has_control_of_LCD_Panel++;     // Debug code... Pan no attention to this stuff
+          SERIAL_ECHO_START;
+          SERIAL_ECHOPGM("Checking G29 has control of LCD Panel:\n");
+          while(!G29_lcd_clicked()) {
+            idle();
+            delay(250);
+            SERIAL_PROTOCOL(G29_encoderDiff);
+            G29_encoderDiff = 0;
+            SERIAL_EOL;
+          }
+          while (G29_lcd_clicked()) idle();
+          UBL_has_control_of_LCD_Panel = 0;;
+          SERIAL_ECHOPGM("G29 giving back control of LCD Panel.\n");
+          break;
+      }
+    }
+
+    if (code_seen('T')) {
+      Z1 = probe_pt(ubl_3_point_1_X, ubl_3_point_1_Y, false /*Stow Flag*/, G29_Verbose_Level) + zprobe_zoffset;
+      Z2 = probe_pt(ubl_3_point_2_X, ubl_3_point_2_Y, false /*Stow Flag*/, G29_Verbose_Level) + zprobe_zoffset;
+      Z3 = probe_pt(ubl_3_point_3_X, ubl_3_point_3_Y, true  /*Stow Flag*/, G29_Verbose_Level) + zprobe_zoffset;
+
+      //  We need to adjust Z1, Z2, Z3 by the Mesh Height at these points. Just because they are non-zero doesn't mean
+      //  the Mesh is tilted!  (We need to compensate each probe point by what the Mesh says that location's height is)
+
+      Z1 -= blm.get_z_correction(ubl_3_point_1_X, ubl_3_point_1_Y);
+      Z2 -= blm.get_z_correction(ubl_3_point_2_X, ubl_3_point_2_Y);
+      Z3 -= blm.get_z_correction(ubl_3_point_3_X, ubl_3_point_3_Y);
+
+      do_blocking_move_to_xy((X_MAX_POS - (X_MIN_POS)) / 2.0, (Y_MAX_POS - (Y_MIN_POS)) / 2.0);
+      tilt_mesh_based_on_3pts(Z1, Z2, Z3);
+    }
+
+    //
+    // Much of the 'What?' command can be eliminated. But until we are fully debugged, it is
+    // good to have the extra information. Soon... we prune this to just a few items
+    //
+    if (code_seen('W')) G29_What_Command();
+
+    //
+    // When we are fully debugged, the EEPROM dump command will get deleted also. But
+    // right now, it is good to have the extra information. Soon... we prune this.
+    //
+    if (code_seen('J')) G29_EEPROM_Dump();   // EEPROM Dump
+
+    //
+    // When we are fully debugged, this may go away. But there are some valid
+    // use cases for the users. So we can wait and see what to do with it.
+    //
+
+    if (code_seen('K')) // Kompare Current Mesh Data to Specified Stored Mesh
+      G29_Kompare_Current_Mesh_to_Stored_Mesh();
+
+    //
+    // Load a Mesh from the EEPROM
+    //
+
+    if (code_seen('L')) {     // Load Current Mesh Data
+      Storage_Slot = code_has_value() ? code_value_int() : blm.state.EEPROM_storage_slot;
+
+      k = E2END - sizeof(blm.state);
+      j = (k - Unified_Bed_Leveling_EEPROM_start) / sizeof(z_values);
+
+      if (Storage_Slot < 0 || Storage_Slot >= j || Unified_Bed_Leveling_EEPROM_start <= 0) {
+        SERIAL_PROTOCOLLNPGM("?EEPROM storage not available for use.\n");
+        return;
+      }
+      blm.load_mesh(Storage_Slot);
+      blm.state.EEPROM_storage_slot = Storage_Slot;
+      if (Storage_Slot != blm.state.EEPROM_storage_slot)
+        blm.store_state();
+      SERIAL_PROTOCOLLNPGM("Done.\n");
+    }
+
+    //
+    // Store a Mesh in the EEPROM
+    //
+
+    if (code_seen('S')) {     // Store (or Save) Current Mesh Data
+      Storage_Slot = code_has_value() ? code_value_int() : blm.state.EEPROM_storage_slot;
+
+      if (Storage_Slot == -1) {                     // Special case, we are going to 'Export' the mesh to the
+        SERIAL_ECHOPGM("G29 I 999\n");                // host in a form it can be reconstructed on a different machine
+        for (i = 0; i < UBL_MESH_NUM_X_POINTS; i++) {
+          for (j = 0;  j < UBL_MESH_NUM_Y_POINTS; j++) {
+            if (!isnan(z_values[i][j])) {
+              SERIAL_ECHOPAIR("M421 I ", i);
+              SERIAL_ECHOPAIR(" J ", j);
+              SERIAL_ECHOPGM(" Z ");
+              SERIAL_PROTOCOL_F(z_values[i][j], 6);
+              SERIAL_EOL;
+            }
+          }
+        }
+        return;
+      }
+
+      int k = E2END - sizeof(blm.state),
+          j = (k - Unified_Bed_Leveling_EEPROM_start) / sizeof(z_values);
+
+      if (Storage_Slot < 0 || Storage_Slot >= j || Unified_Bed_Leveling_EEPROM_start <= 0) {
+        SERIAL_PROTOCOLLNPGM("?EEPROM storage not available for use.\n");
+        SERIAL_PROTOCOLLNPAIR("?Use 0 to ", j - 1);
+        goto LEAVE;
+      }
+      blm.store_mesh(Storage_Slot);
+      blm.state.EEPROM_storage_slot = Storage_Slot;
+      //
+      //  if (Storage_Slot != blm.state.EEPROM_storage_slot)
+      blm.store_state();    // Always save an updated copy of the UBL State info
+
+      SERIAL_PROTOCOLLNPGM("Done.\n");
+    }
+
+    if (code_seen('O') || code_seen('M')) {
+      i = code_has_value() ? code_value_int() : 0;
+      blm.display_map(i);
+    }
+
+    if (code_seen('Z')) {
+      if (code_has_value()) {
+        blm.state.z_offset = code_value_float();   // do the simple case. Just lock in the specified value
+      }
+      else {
+        save_UBL_active_state_and_disable();
+        //measured_z = probe_pt(X_Pos + X_PROBE_OFFSET_FROM_EXTRUDER, Y_Pos+Y_PROBE_OFFSET_FROM_EXTRUDER, ProbeDeployAndStow, G29_Verbose_Level);
+
+        measured_z = 1.5;
+        do_blocking_move_to_z(measured_z);  // Get close to the bed, but leave some space so we don't damage anything
+                                            // The user is not going to be locking in a new Z-Offset very often so
+                                            // it won't be that painful to spin the Encoder Wheel for 1.5mm
+        lcd_implementation_clear();
+        lcd_z_offset_edit_setup(measured_z);
+        do {
+          measured_z = lcd_z_offset_edit();
+          idle();
+          do_blocking_move_to_z(measured_z);
+        } while (!G29_lcd_clicked());
+
+        UBL_has_control_of_LCD_Panel = 1; // There is a race condition for the Encoder Wheel getting clicked.
+                                          // It could get detected in lcd_mesh_edit (actually _lcd_mesh_fine_tune( )
+                                          // or here. So, until we are done looking for a long Encoder Wheel Press,
+                                          // we need to take control of the panel
+        millis_t nxt = millis() + 1500UL;
+        lcd_return_to_status();
+        while (G29_lcd_clicked()) { // debounce and watch for abort
+          idle();
+          if (ELAPSED(millis(), nxt)) {
+            SERIAL_PROTOCOLLNPGM("\nZ-Offset Adjustment Stopped.");
+            do_blocking_move_to_z(Z_CLEARANCE_DEPLOY_PROBE);
+            lcd_setstatus("Z-Offset Stopped", true);
+
+            while (G29_lcd_clicked()) idle();
+
+            UBL_has_control_of_LCD_Panel = 0;
+            restore_UBL_active_state_and_leave();
+            goto LEAVE;
+          }
+        }
+        UBL_has_control_of_LCD_Panel = 0;
+        delay(20); // We don't want any switch noise.
+
+        blm.state.z_offset = measured_z;
+
+        lcd_implementation_clear();
+        restore_UBL_active_state_and_leave();
+      }
+    }
+
+    LEAVE:
+    #if ENABLED(ULTRA_LCD)
+      lcd_setstatus("                         ", true);
+      lcd_quick_feedback();
+    #endif
+    UBL_has_control_of_LCD_Panel = 0;
+  }
+
+  void Find_Mean_Mesh_Height()  {
+    int i, j, n;
+    float sum, sum_of_diff_squared, sigma, difference, mean;
+
+    sum = sum_of_diff_squared = 0.0;
+    n = 0;
+    for (i = 0; i < UBL_MESH_NUM_X_POINTS; i++) {
+      for (j = 0; j < UBL_MESH_NUM_Y_POINTS; j++) {
+        if (!isnan(z_values[i][j])) {
+          sum += z_values[i][j];
+          n++;
+        }
+      }
+    }
+    mean = sum / n;
+    //
+    // Now do the sumation of the squares of difference from mean
+    //
+    for (i = 0; i < UBL_MESH_NUM_X_POINTS; i++) {
+      for (j = 0;  j < UBL_MESH_NUM_Y_POINTS; j++) {
+        if (!isnan(z_values[i][j])) {
+          difference = (z_values[i][j] - mean);
+          sum_of_diff_squared += difference * difference;
+        }
+      }
+    }
+    SERIAL_ECHOLNPAIR("# of samples: ", n);
+    SERIAL_ECHOPGM("Mean Mesh Height: ");
+    SERIAL_PROTOCOL_F(mean, 6);
+    SERIAL_EOL;
+
+    sigma = sqrt( sum_of_diff_squared / (n + 1));
+    SERIAL_ECHOPGM("Standard Deviation: ");
+    SERIAL_PROTOCOL_F(sigma, 6);
+    SERIAL_EOL;
+
+    if (C_Flag)
+      for (i = 0; i < UBL_MESH_NUM_X_POINTS; i++)
+        for (j = 0;  j < UBL_MESH_NUM_Y_POINTS; j++)
+          if (!isnan(z_values[i][j]))
+            z_values[i][j] -= mean + Constant;
+  }
+
+  void Shift_Mesh_Height( )  {
+    for (uint8_t i = 0; i < UBL_MESH_NUM_X_POINTS; i++)
+      for (uint8_t j = 0;  j < UBL_MESH_NUM_Y_POINTS; j++)
+        if (!isnan(z_values[i][j]))
+          z_values[i][j] += Constant;
+  }
+
+  // probe_entire_mesh(X_Pos, Y_Pos)  probes all invalidated locations of the mesh that can be reached
+  // by the probe. It attempts to fill in locations closest to the nozzle's start location first.
+
+  void probe_entire_mesh(float X_Pos, float Y_Pos, bool do_UBL_MESH_Map, bool stow_probe)  {
+    mesh_index_pair location;
+    float xProbe, yProbe, measured_z;
+
+    UBL_has_control_of_LCD_Panel++;
+    save_UBL_active_state_and_disable();   // we don't do bed level correction because we want the raw data when we probe
+    DEPLOY_PROBE();
+
+    do {
+      if (G29_lcd_clicked()) {
+        SERIAL_PROTOCOLLNPGM("\nMesh only partially populated.");
+        lcd_quick_feedback();
+        while (G29_lcd_clicked()) idle();
+        UBL_has_control_of_LCD_Panel = 0;
+        STOW_PROBE();
+        restore_UBL_active_state_and_leave();
+        return;
+      }
+      location = find_closest_mesh_point_of_type( INVALID, X_Pos,  Y_Pos, 1, NULL);  // the '1' says we want the location to be relative to the probe
+      if (location.x_index>=0 && location.y_index>=0) {
+        xProbe = blm.map_x_index_to_bed_location(location.x_index);
+        yProbe = blm.map_y_index_to_bed_location(location.y_index);
+        if (xProbe < MIN_PROBE_X || xProbe > MAX_PROBE_X || yProbe < MIN_PROBE_Y || yProbe > MAX_PROBE_Y) {
+          SERIAL_PROTOCOLLNPGM("?Error: Attempt to probe off the bed.");
+          UBL_has_control_of_LCD_Panel = 0;
+          goto LEAVE;
+        }
+        measured_z = probe_pt(xProbe, yProbe, stow_probe, G29_Verbose_Level);
+        z_values[location.x_index][location.y_index] = measured_z + Z_PROBE_OFFSET_FROM_EXTRUDER;
+      }
+
+      if (do_UBL_MESH_Map) blm.display_map(1);
+    } while (location.x_index >= 0 && location.y_index >= 0);
+
+    LEAVE:
+    STOW_PROBE();
+    restore_UBL_active_state_and_leave();
+
+    X_Pos = constrain( X_Pos-X_PROBE_OFFSET_FROM_EXTRUDER, X_MIN_POS, X_MAX_POS);
+    Y_Pos = constrain( Y_Pos-Y_PROBE_OFFSET_FROM_EXTRUDER, Y_MIN_POS, Y_MAX_POS);
+
+    do_blocking_move_to_xy(X_Pos, Y_Pos);
+  }
+
+  struct vector tilt_mesh_based_on_3pts(float pt1, float pt2, float pt3) {
+    struct vector v1, v2, normal;
+    float c, d, t;
+    int i, j;
+
+    v1.dx = (ubl_3_point_1_X - ubl_3_point_2_X);
+    v1.dy = (ubl_3_point_1_Y - ubl_3_point_2_Y);
+    v1.dz = (pt1 - pt2);
+
+    v2.dx = (ubl_3_point_3_X - ubl_3_point_2_X);
+    v2.dy = (ubl_3_point_3_Y - ubl_3_point_2_Y);
+    v2.dz = (pt3 - pt2);
+
+    // do cross product
+
+    normal.dx = v1.dy * v2.dz - v1.dz * v2.dy;
+    normal.dy = v1.dz * v2.dx - v1.dx * v2.dz;
+    normal.dz = v1.dx * v2.dy - v1.dy * v2.dx;
+
+    // printf("[%f,%f,%f]    ", normal.dx, normal.dy, normal.dz);
+
+    normal.dx /= normal.dz; // This code does two things. This vector is normal to the tilted plane.
+    normal.dy /= normal.dz; // However, we don't know its direction. We need it to point up. So if
+    normal.dz /= normal.dz; // Z is negative, we need to invert the sign of all components of the vector
+    // We also need Z to be unity because we are going to be treating this triangle
+    // as the sin() and cos() of the bed's tilt
+
+    //
+    // All of 3 of these points should give us the same d constant
+    //
+    t = normal.dx * ubl_3_point_1_X + normal.dy * ubl_3_point_1_Y;
+    d = t + normal.dz * pt1;
+    c = d - t;
+    SERIAL_ECHOPGM("d from 1st point: ");
+    SERIAL_PROTOCOL_F(d, 6);
+    SERIAL_ECHOPGM("  c: ");
+    SERIAL_PROTOCOL_F(c, 6);
+    SERIAL_EOL;
+    t = normal.dx * ubl_3_point_2_X + normal.dy * ubl_3_point_2_Y;
+    d = t + normal.dz * pt2;
+    c = d - t;
+    SERIAL_ECHOPGM("d from 2nd point: ");
+    SERIAL_PROTOCOL_F(d, 6);
+    SERIAL_ECHOPGM("  c: ");
+    SERIAL_PROTOCOL_F(c, 6);
+    SERIAL_EOL;
+    t = normal.dx * ubl_3_point_3_X + normal.dy * ubl_3_point_3_Y;
+    d = t + normal.dz * pt3;
+    c = d - t;
+    SERIAL_ECHOPGM("d from 3rd point: ");
+    SERIAL_PROTOCOL_F(d, 6);
+    SERIAL_ECHOPGM("  c: ");
+    SERIAL_PROTOCOL_F(c, 6);
+    SERIAL_EOL;
+
+    for (i = 0; i < UBL_MESH_NUM_X_POINTS; i++) {
+      for (j = 0; j < UBL_MESH_NUM_Y_POINTS; j++) {
+        c = -((normal.dx * (UBL_MESH_MIN_X + i * (MESH_X_DIST)) + normal.dy * (UBL_MESH_MIN_Y + j * (MESH_Y_DIST))) - d);
+        z_values[i][j] += c;
+      }
+    }
+    return normal;
+  }
+
+  float use_encoder_wheel_to_measure_point() {
+    UBL_has_control_of_LCD_Panel++;
+    while (!G29_lcd_clicked()) {     // we need the loop to move the nozzle based on the encoder wheel here!
+      idle();
+      if (G29_encoderDiff != 0) {
+        float new_z;
+        // We define a new variable so we can know ahead of time where we are trying to go.
+        // The reason is we want G29_encoderDiff cleared so an interrupt can update it even before the move
+        // is complete. (So the dial feels responsive to user)
+        new_z = current_position[Z_AXIS] + 0.01 * float(G29_encoderDiff);
+        G29_encoderDiff = 0;
+        do_blocking_move_to_z(new_z);
+      }
+    }
+    while (G29_lcd_clicked()) idle(); // debounce and wait
+    UBL_has_control_of_LCD_Panel--;
+    return current_position[Z_AXIS];
+  }
+
+  float measure_business_card_thickness(float Height_Value) {
+    float Z1, Z2;
+
+    UBL_has_control_of_LCD_Panel++;
+    save_UBL_active_state_and_disable();   // we don't do bed level correction because we want the raw data when we probe
+
+    SERIAL_PROTOCOLLNPGM("Place Shim Under Nozzle and Perform Measurement.");
+    do_blocking_move_to_z(Height_Value);
+    do_blocking_move_to_xy((float(X_MAX_POS) - float(X_MIN_POS)) / 2.0, (float(Y_MAX_POS) - float(Y_MIN_POS)) / 2.0);
+      //, min( planner.max_feedrate_mm_s[X_AXIS], planner.max_feedrate_mm_s[Y_AXIS])/2.0);
+
+    Z1 = use_encoder_wheel_to_measure_point();
+    do_blocking_move_to_z(current_position[Z_AXIS] + SIZE_OF_LITTLE_RAISE);
+    UBL_has_control_of_LCD_Panel = 0;
+
+    SERIAL_PROTOCOLLNPGM("Remove Shim and Measure Bed Height.");
+    Z2 = use_encoder_wheel_to_measure_point();
+    do_blocking_move_to_z(current_position[Z_AXIS] + SIZE_OF_LITTLE_RAISE);
+
+    if (G29_Verbose_Level > 1) {
+      SERIAL_ECHOPGM("Business Card is: ");
+      SERIAL_PROTOCOL_F(abs(Z1 - Z2), 6);
+      SERIAL_PROTOCOLLNPGM("mm thick.");
+    }
+    restore_UBL_active_state_and_leave();
+    return abs(Z1 - Z2);
+  }
+
+  void manually_probe_remaining_mesh(float X_Pos, float Y_Pos, float z_clearance, float card_thickness, bool do_UBL_MESH_Map) {
+    mesh_index_pair location;
+    float last_x, last_y, dx, dy,
+          xProbe, yProbe;
+    unsigned long cnt;
+
+    UBL_has_control_of_LCD_Panel++;
+    last_x = last_y = -9999.99;
+    save_UBL_active_state_and_disable();   // we don't do bed level correction because we want the raw data when we probe
+    do_blocking_move_to_z(z_clearance);
+    do_blocking_move_to_xy(X_Pos, Y_Pos);
+
+    do {
+      if (do_UBL_MESH_Map) blm.display_map(1);
+
+      location = find_closest_mesh_point_of_type(INVALID, X_Pos, Y_Pos, 0, NULL); // The '0' says we want to use the nozzle's position
+      // It doesn't matter if the probe can not reach the
+      // NAN location. This is a manual probe.
+      if (location.x_index < 0 && location.y_index < 0) continue;
+
+      xProbe = blm.map_x_index_to_bed_location(location.x_index);
+      yProbe = blm.map_y_index_to_bed_location(location.y_index);
+      if (xProbe < (X_MIN_POS) || xProbe > (X_MAX_POS) || yProbe < (Y_MIN_POS) || yProbe > (Y_MAX_POS))  {
+        SERIAL_PROTOCOLLNPGM("?Error: Attempt to probe off the bed.");
+        UBL_has_control_of_LCD_Panel = 0;
+        goto LEAVE;
+      }
+
+      dx = xProbe - last_x;
+      dy = yProbe - last_y;
+
+      if (HYPOT(dx, dy) < BIG_RAISE_NOT_NEEDED)
+        do_blocking_move_to_z(current_position[Z_AXIS] + SIZE_OF_LITTLE_RAISE);
+      else
+        do_blocking_move_to_z(z_clearance);
+
+      last_x = xProbe;
+      last_y = yProbe;
+      do_blocking_move_to_xy(xProbe, yProbe);
+
+      while (!G29_lcd_clicked()) {     // we need the loop to move the nozzle based on the encoder wheel here!
+        idle();
+        if (G29_encoderDiff) {
+          float new_z;
+          // We define a new variable so we can know ahead of time where we are trying to go.
+          // The reason is we want G29_encoderDiff cleared so an interrupt can update it even before the move
+          // is complete. (So the dial feels responsive to user)
+          new_z = current_position[Z_AXIS] + float(G29_encoderDiff) / 100.0;
+          G29_encoderDiff = 0;
+          do_blocking_move_to_z(new_z);
+        }
+      }
+
+      cnt = millis();
+      while (G29_lcd_clicked()) {     // debounce and watch for abort
+        idle();
+        if (millis() - cnt > 1500L) {
+          SERIAL_PROTOCOLLNPGM("\nMesh only partially populated.");
+          do_blocking_move_to_z(Z_CLEARANCE_DEPLOY_PROBE);
+          lcd_quick_feedback();
+          while (G29_lcd_clicked()) idle();
+          UBL_has_control_of_LCD_Panel = 0;
+          restore_UBL_active_state_and_leave();
+          return;
+        }
+      }
+
+      z_values[location.x_index][location.y_index] = current_position[Z_AXIS] - card_thickness;
+      if (G29_Verbose_Level > 2) {
+        SERIAL_PROTOCOL("Mesh Point Measured at: ");
+        SERIAL_PROTOCOL_F(z_values[location.x_index][location.y_index], 6);
+        SERIAL_EOL;
+      }
+    } while (location.x_index >= 0 && location.y_index >= 0);
+
+    if (do_UBL_MESH_Map) blm.display_map(1);
+
+    LEAVE:
+    restore_UBL_active_state_and_leave();
+    do_blocking_move_to_z(Z_CLEARANCE_DEPLOY_PROBE);
+    do_blocking_move_to_xy(X_Pos, Y_Pos);
+  }
+
+  bool G29_Parameter_Parsing() {
+
+    #if ENABLED(ULTRA_LCD)
+      lcd_setstatus("Doing G29 UBL !", true);
+      lcd_quick_feedback();
+    #endif
+
+    X_Pos = current_position[X_AXIS];
+    Y_Pos = current_position[Y_AXIS];
+    X_Flag = Y_Flag = Repeat_Flag = UBL_OK;
+    Constant = 0.0;
+    Repetition_Cnt = 1;
+
+    if ((X_Flag = code_seen('X'))) {
+      X_Pos = code_value_float();
+      if (X_Pos < X_MIN_POS || X_Pos > X_MAX_POS) {
+        SERIAL_PROTOCOLLNPGM("Invalid X location specified.\n");
+        return UBL_ERR;
+      }
+    }
+
+    if ((Y_Flag = code_seen('Y'))) {
+      Y_Pos = code_value_float();
+      if (Y_Pos < Y_MIN_POS || Y_Pos > Y_MAX_POS) {
+        SERIAL_PROTOCOLLNPGM("Invalid Y location specified.\n");
+        return UBL_ERR;
+      }
+    }
+
+    if (X_Flag != Y_Flag) {
+      SERIAL_PROTOCOLLNPGM("Both X & Y locations must be specified.\n");
+      return UBL_ERR;
+    }
+
+    G29_Verbose_Level = 0;
+    if (code_seen('V')) {
+      G29_Verbose_Level = code_value_int();
+      if (G29_Verbose_Level < 0 || G29_Verbose_Level > 4) {
+        SERIAL_PROTOCOLLNPGM("Invalid Verbose Level specified. (0-4)\n");
+        return UBL_ERR;
+      }
+    }
+
+    if (code_seen('A')) {     // Activate the Unified Bed Leveling System
+      blm.state.active = 1;
+      SERIAL_PROTOCOLLNPGM("Unified Bed Leveling System activated.\n");
+      blm.store_state();
+    }
+
+    if ((C_Flag = code_seen('C')) && code_has_value())
+      Constant = code_value_float();
+
+    if (code_seen('D')) {     // Disable the Unified Bed Leveling System
+      blm.state.active = 0;
+      SERIAL_PROTOCOLLNPGM("Unified Bed Leveling System de-activated.\n");
+      blm.store_state();
+    }
+
+    if (code_seen('F')) {
+      blm.state.G29_Correction_Fade_Height = 10.00;
+      if (code_has_value()) {
+        blm.state.G29_Correction_Fade_Height = code_value_float();
+        blm.state.G29_Fade_Height_Multiplier = 1.0 / blm.state.G29_Correction_Fade_Height;
+      }
+      if (blm.state.G29_Correction_Fade_Height<0.0 || blm.state.G29_Correction_Fade_Height>100.0) {
+        SERIAL_PROTOCOLLNPGM("?Bed Level Correction Fade Height Not Plausable.\n");
+        blm.state.G29_Correction_Fade_Height = 10.00;
+        blm.state.G29_Fade_Height_Multiplier = 1.0 / blm.state.G29_Correction_Fade_Height;
+        return UBL_ERR;
+      }
+    }
+
+    if ((Repeat_Flag = code_seen('R'))) {
+      Repetition_Cnt = code_has_value() ? code_value_int() : 9999;
+      if (Repetition_Cnt < 1) {
+        SERIAL_PROTOCOLLNPGM("Invalid Repetition count.\n");
+        return UBL_ERR;
+      }
+    }
+    return UBL_OK;
+  }
+
+  /**
+   * This function goes away after G29 debug is complete. But for right now, it is a handy
+   * routine to dump binary data structures.
+   */
+  void dump(char *str, float f) {
+    char *ptr;
+
+    SERIAL_PROTOCOL(str);
+    SERIAL_PROTOCOL_F(f, 8);
+    SERIAL_PROTOCOL("  ");
+    ptr = (char *)&f;
+    for (uint8_t i = 0; i < 4; i++) {
+      SERIAL_PROTOCOL("  ");
+      prt_hex_byte(*ptr++);
+    }
+    SERIAL_PROTOCOL("  isnan()=");
+    SERIAL_PROTOCOL(isnan(f));
+    SERIAL_PROTOCOL("  isinf()=");
+    SERIAL_PROTOCOL(isinf(f));
+
+    constexpr float g = INFINITY;
+    if (f == -g)
+      SERIAL_PROTOCOL("  Minus Infinity detected.");
+
+    SERIAL_EOL;
+  }
+
+  static int UBL_state_at_invokation = 0,
+             UBL_state_recursion_chk = 0;
+
+  void save_UBL_active_state_and_disable() {
+    UBL_state_recursion_chk++;
+    if (UBL_state_recursion_chk != 1) {
+      SERIAL_ECHOLNPGM("save_UBL_active_state_and_disabled() called multiple times in a row.");
+      lcd_setstatus("save_UBL_active() error", true);
+      lcd_quick_feedback();
+      return;
+    }
+    UBL_state_at_invokation = blm.state.active;
+    blm.state.active = 0;
+    return;
+  }
+
+  void restore_UBL_active_state_and_leave() {
+    if (--UBL_state_recursion_chk) {
+      SERIAL_ECHOLNPGM("restore_UBL_active_state_and_leave() called too many times.");
+      lcd_setstatus("restore_UBL_active() error", true);
+      lcd_quick_feedback();
+      return;
+    }
+    blm.state.active = UBL_state_at_invokation;
+  }
+
+  /**
+   * Much of the 'What?' command can be eliminated. But until we are fully debugged, it is
+   * good to have the extra information. Soon... we prune this to just a few items
+   */
+  void G29_What_Command() {
+    int k, i;
+    k = E2END - Unified_Bed_Leveling_EEPROM_start;
+    Statistics_Flag++;
+
+    SERIAL_PROTOCOLPGM("Version #4: 10/30/2016 branch \n");
+    SERIAL_PROTOCOLPGM("Unified Bed Leveling System ");
+    if (blm.state.active)
+      SERIAL_PROTOCOLPGM("Active.");
+    else
+      SERIAL_PROTOCOLPGM("Inactive.");
+    SERIAL_PROTOCOLLNPGM("  -------------------------------------       <----<<<");  // These arrows are just to help me
+
+    if (blm.state.EEPROM_storage_slot == 0xFFFF)  {
+      SERIAL_PROTOCOLPGM("No Mesh Loaded.");
+      SERIAL_PROTOCOLLNPGM("  -------------------------------------       <----<<<"); // These arrows are just to help me
+      // find this info buried in the clutter
+    }
+    else {
+      SERIAL_PROTOCOLPGM("Mesh: ");
+      prt_hex_word(blm.state.EEPROM_storage_slot);
+      SERIAL_PROTOCOLPGM(" Loaded. ");
+      SERIAL_PROTOCOLLNPGM("  --------------------------------------------------------       <----<<<"); // These arrows are just to help me
+      // find this info buried in the clutter
+    }
+
+    SERIAL_ECHOPAIR("\nG29_Correction_Fade_Height : ", blm.state.G29_Correction_Fade_Height );
+    SERIAL_PROTOCOLPGM("  -------------------------------------       <----<<< \n");  // These arrows are just to help me
+    // find this info buried in the clutter
+    idle();
+
+    SERIAL_ECHOPGM("z_offset: ");
+    SERIAL_PROTOCOL_F(blm.state.z_offset, 6);
+    SERIAL_PROTOCOLLNPGM("  ------------------------------------------------------------       <----<<<");
+
+    SERIAL_PROTOCOLPGM("X-Axis Mesh Points at: ");
+    for (i = 0; i < UBL_MESH_NUM_X_POINTS; i++) {
+      SERIAL_PROTOCOL_F( blm.map_x_index_to_bed_location(i), 1);
+      SERIAL_PROTOCOLPGM("  ");
+    }
+    SERIAL_EOL;
+    SERIAL_PROTOCOLPGM("Y-Axis Mesh Points at: ");
+    for (i = 0; i < UBL_MESH_NUM_Y_POINTS; i++) {
+      SERIAL_PROTOCOL_F( blm.map_y_index_to_bed_location(i), 1);
+      SERIAL_PROTOCOLPGM("  ");
+    }
+    SERIAL_EOL;
+
+    #if HAS_KILL
+      SERIAL_ECHOPAIR("Kill pin on :", KILL_PIN);
+      SERIAL_ECHOLNPAIR("  state:", READ(KILL_PIN));
+    #endif
+
+    SERIAL_ECHOLNPAIR("UBL_state_at_invokation :", UBL_state_at_invokation);
+    SERIAL_ECHOLNPAIR("UBL_state_recursion_chk :", UBL_state_recursion_chk);
+
+    SERIAL_EOL;
+    SERIAL_PROTOCOLPGM("Free EEPROM space starts at: 0x");
+    prt_hex_word(Unified_Bed_Leveling_EEPROM_start);
+    SERIAL_EOL;
+    idle();
+
+    SERIAL_PROTOCOLPGM("end of EEPROM              : ");
+    prt_hex_word(E2END);
+    SERIAL_EOL;
+    idle();
+
+    SERIAL_PROTOCOLLNPAIR("sizeof(blm) :  ", (int)sizeof(blm));
+    SERIAL_EOL;
+    SERIAL_PROTOCOLLNPAIR("z_value[][] size: ", (int)sizeof(z_values));
+    SERIAL_EOL;
+
+    SERIAL_PROTOCOLPGM("EEPROM free for UBL: 0x");
+    prt_hex_word(k);
+    SERIAL_EOL;
+    idle();
+
+    SERIAL_PROTOCOLPGM("EEPROM can hold 0x");
+    prt_hex_word(k / sizeof(z_values));
+    SERIAL_PROTOCOLPGM(" meshes. \n");
+
+    SERIAL_PROTOCOLPGM("sizeof(stat)     :");
+    prt_hex_word(sizeof(blm.state));
+    SERIAL_EOL;
+    idle();
+
+    SERIAL_ECHOPAIR("\nUBL_MESH_NUM_X_POINTS  ", UBL_MESH_NUM_X_POINTS);
+    SERIAL_ECHOPAIR("\nUBL_MESH_NUM_Y_POINTS  ", UBL_MESH_NUM_Y_POINTS);
+    SERIAL_ECHOPAIR("\nUBL_MESH_MIN_X         ", UBL_MESH_MIN_X);
+    SERIAL_ECHOPAIR("\nUBL_MESH_MIN_Y         ", UBL_MESH_MIN_Y);
+    SERIAL_ECHOPAIR("\nUBL_MESH_MAX_X         ", UBL_MESH_MAX_X);
+    SERIAL_ECHOPAIR("\nUBL_MESH_MAX_Y         ", UBL_MESH_MAX_Y);
+    SERIAL_ECHOPGM("\nMESH_X_DIST        ");
+    SERIAL_PROTOCOL_F(MESH_X_DIST, 6);
+    SERIAL_ECHOPGM("\nMESH_Y_DIST        ");
+    SERIAL_PROTOCOL_F(MESH_Y_DIST, 6);
+    SERIAL_EOL;
+    idle();
+
+    SERIAL_ECHOPAIR("\nsizeof(block_t): ", (int)sizeof(block_t));
+    SERIAL_ECHOPAIR("\nsizeof(planner.block_buffer): ", (int)sizeof(planner.block_buffer));
+    SERIAL_ECHOPAIR("\nsizeof(char): ", (int)sizeof(char));
+    SERIAL_ECHOPAIR("   sizeof(unsigned char): ", (int)sizeof(unsigned char));
+    SERIAL_ECHOPAIR("\nsizeof(int): ", (int)sizeof(int));
+    SERIAL_ECHOPAIR("   sizeof(unsigned int): ", (int)sizeof(unsigned int));
+    SERIAL_ECHOPAIR("\nsizeof(long): ", (int)sizeof(long));
+    SERIAL_ECHOPAIR("   sizeof(unsigned long int): ", (int)sizeof(unsigned long int));
+    SERIAL_ECHOPAIR("\nsizeof(float): ", (int)sizeof(float));
+    SERIAL_ECHOPAIR("   sizeof(double): ", (int)sizeof(double));
+    SERIAL_ECHOPAIR("\nsizeof(void *): ", (int)sizeof(void *));
+    struct pf { void *p_f(); } ptr_func;
+    SERIAL_ECHOPAIR("   sizeof(struct pf): ", (int)sizeof(pf));
+    SERIAL_ECHOPAIR("   sizeof(void *()): ", (int)sizeof(ptr_func));
+    SERIAL_EOL;
+
+    idle();
+
+    if (!blm.sanity_check())
+      SERIAL_PROTOCOLLNPGM("Unified Bed Leveling sanity checks passed.");
+  }
+
+  /**
+   * When we are fully debugged, the EEPROM dump command will get deleted also. But
+   * right now, it is good to have the extra information. Soon... we prune this.
+   */
+  void G29_EEPROM_Dump() {
+    unsigned char cccc;
+    int i, j, kkkk;
+
+    SERIAL_ECHO_START;
+    SERIAL_ECHOPGM("EEPROM Dump:\n");
+    for (i = 0; i < E2END + 1; i += 16) {
+      if (i & 0x3 == 0) idle();
+      prt_hex_word(i);
+      SERIAL_ECHOPGM(": ");
+      for (j = 0; j < 16; j++) {
+        kkkk = i + j;
+        eeprom_read_block(&cccc, (void *)kkkk, 1);
+        prt_hex_byte(cccc);
+        SERIAL_ECHO(' ');
+      }
+      SERIAL_EOL;
+    }
+    SERIAL_EOL;
+    return;
+  }
+
+  /**
+   * When we are fully debugged, this may go away. But there are some valid
+   * use cases for the users. So we can wait and see what to do with it.
+   */
+  void G29_Kompare_Current_Mesh_to_Stored_Mesh()  {
+    float tmp_z_values[UBL_MESH_NUM_X_POINTS][UBL_MESH_NUM_Y_POINTS];
+    int i, j, k;
+
+    if (!code_has_value()) {
+      SERIAL_PROTOCOLLNPGM("?Mesh # required.\n");
+      return;
+    }
+    Storage_Slot = code_value_int();
+
+    k = E2END - sizeof(blm.state);
+    j = (k - Unified_Bed_Leveling_EEPROM_start) / sizeof(tmp_z_values);
+
+    if (Storage_Slot < 0 || Storage_Slot > j || Unified_Bed_Leveling_EEPROM_start <= 0) {
+      SERIAL_PROTOCOLLNPGM("?EEPROM storage not available for use.\n");
+      return;
+    }
+
+    j = k - (Storage_Slot + 1) * sizeof(tmp_z_values);
+    eeprom_read_block((void *)&tmp_z_values, (void *)j, sizeof(tmp_z_values));
+
+    SERIAL_ECHOPAIR("Subtracting Mesh ", Storage_Slot);
+    SERIAL_PROTOCOLPGM(" loaded from EEPROM address ");   // Soon, we can remove the extra clutter of printing
+    prt_hex_word(j);            // the address in the EEPROM where the Mesh is stored.
+    SERIAL_EOL;
+
+    for (i = 0; i < UBL_MESH_NUM_X_POINTS; i++)
+      for (j = 0; j < UBL_MESH_NUM_Y_POINTS; j++)
+        z_values[i][j] = z_values[i][j] - tmp_z_values[i][j];
+  }
+
+  mesh_index_pair find_closest_mesh_point_of_type(Mesh_Point_Type type, float X, float Y, bool probe_as_reference, unsigned int bits[16]) {
+    int i, j;
+    float f, px, py, mx, my, dx, dy, closest = 99999.99;
+    float current_x, current_y, distance;
+    mesh_index_pair return_val;
+
+    return_val.x_index = return_val.y_index = -1;
+
+    current_x = current_position[X_AXIS];
+    current_y = current_position[Y_AXIS];
+
+    px = X;       // Get our reference position. Either the nozzle or
+    py = Y;       // the probe location.
+    if (probe_as_reference) {
+      px -= X_PROBE_OFFSET_FROM_EXTRUDER;
+      py -= Y_PROBE_OFFSET_FROM_EXTRUDER;
+    }
+
+    for (i = 0; i < UBL_MESH_NUM_X_POINTS; i++) {
+      for (j = 0; j < UBL_MESH_NUM_Y_POINTS; j++) {
+
+        if ( (type == INVALID && isnan(z_values[i][j]))  // Check to see if this location holds the right thing
+          || (type == REAL && !isnan(z_values[i][j]))
+          || (type == SET_IN_BITMAP && is_bit_set(bits, i, j))
+        ) {
+
+          // We only get here if we found a Mesh Point of the specified type
+
+          mx = blm.map_x_index_to_bed_location(i); // Check if we can probe this mesh location
+          my = blm.map_y_index_to_bed_location(j);
+
+          // If we are using the probe as the reference
+          // there are some locations we can't get to.
+          // We prune these out of the list and ignore
+          // them until the next Phase where we do the
+          // manual nozzle probing.
+          if (probe_as_reference
+            && (mx < (MIN_PROBE_X) || mx > (MAX_PROBE_X))
+            && (my < (MIN_PROBE_Y) || my > (MAX_PROBE_Y))
+          ) continue;
+
+          dx = px - mx;         // We can get to it. Let's see if it is the
+          dy = py - my;         // closest location to the nozzle.
+          distance = HYPOT(dx, dy);
+
+          dx = current_x - mx;                    // We are going to add in a weighting factor that considers
+          dy = current_y - my;                    // the current location of the nozzle. If two locations are equal
+          distance += HYPOT(dx, dy) * 0.01;       // distance from the measurement location, we are going to give
+
+          if (distance < closest) {
+            closest = distance;       // We found a closer location with
+            return_val.x_index = i;   // the specified type of mesh value.
+            return_val.y_index = j;
+            return_val.distance = closest;
+          }
+        }
+      }
+    }
+    return return_val;
+  }
+
+  void fine_tune_mesh(float X_Pos, float Y_Pos, float Height_Value, bool do_UBL_MESH_Map) {
+    mesh_index_pair location;
+    float xProbe, yProbe, new_z;
+    uint16_t i, not_done[16];
+    long round_off;
+
+    save_UBL_active_state_and_disable();
+    memset(not_done, 0xFF, sizeof(not_done));
+
+    #if ENABLED(ULTRA_LCD)
+      lcd_setstatus("Fine Tuning Mesh.", true);
+    #endif
+
+    do_blocking_move_to_z(Z_CLEARANCE_DEPLOY_PROBE);
+    do_blocking_move_to_xy(X_Pos, Y_Pos);
+    do {
+      if (do_UBL_MESH_Map) blm.display_map(1);
+
+      location = find_closest_mesh_point_of_type( SET_IN_BITMAP, X_Pos,  Y_Pos, 0, not_done); // The '0' says we want to use the nozzle's position
+                                                                                              // It doesn't matter if the probe can not reach this
+                                                                                              // location. This is a manual edit of the Mesh Point.
+      if (location.x_index < 0 && location.y_index < 0) continue; // abort if we can't find any more points.
+
+      bit_clear(not_done, location.x_index, location.y_index);  // Mark this location as 'adjusted' so we will find a
+                                                                // different location the next time through the loop
+
+      xProbe = blm.map_x_index_to_bed_location(location.x_index);
+      yProbe = blm.map_y_index_to_bed_location(location.y_index);
+      if (xProbe < X_MIN_POS || xProbe > X_MAX_POS || yProbe < Y_MIN_POS || yProbe > Y_MAX_POS) { // In theory, we don't need this check.
+        SERIAL_PROTOCOLLNPGM("?Error: Attempt to edit off the bed.");                             // This really can't happen, but for now,
+        UBL_has_control_of_LCD_Panel = 0;                                                         // Let's do the check.
+        goto FINE_TUNE_EXIT;
+      }
+
+      do_blocking_move_to_z(Z_CLEARANCE_DEPLOY_PROBE);    // Move the nozzle to where we are going to edit
+      do_blocking_move_to_xy(xProbe, yProbe);
+      new_z = z_values[location.x_index][location.y_index] + 0.001;
+
+      round_off = (int32_t)(new_z * 1000.0 + 2.5); // we chop off the last digits just to be clean. We are rounding to the
+      round_off -= (round_off % 5L); // closest 0 or 5 at the 3rd decimal place.
+      new_z = ((float)(round_off)) / 1000.0;
+
+      //SERIAL_ECHOPGM("Mesh Point Currently At:  ");
+      //SERIAL_PROTOCOL_F(new_z, 6);
+      //SERIAL_EOL;
+
+      lcd_implementation_clear();
+      lcd_mesh_edit_setup(new_z);
+      UBL_has_control_of_LCD_Panel++;
+      do {
+        new_z = lcd_mesh_edit();
+        idle();
+      } while (!G29_lcd_clicked());
+
+      UBL_has_control_of_LCD_Panel = 1; // There is a race condition for the Encoder Wheel getting clicked.
+                                        // It could get detected in lcd_mesh_edit (actually _lcd_mesh_fine_tune( )
+                                        // or here.
+      millis_t nxt = millis() + 1500UL;
+      lcd_return_to_status();
+      while (G29_lcd_clicked()) { // debounce and watch for abort
+        idle();
+        if (ELAPSED(millis(), nxt)) {
+          lcd_return_to_status();
+          SERIAL_PROTOCOLLNPGM("\nFine Tuning of Mesh Stopped.");
+          do_blocking_move_to_z(Z_CLEARANCE_DEPLOY_PROBE);
+          lcd_setstatus("Mesh Editing Stopped", true);
+
+          while (G29_lcd_clicked()) idle();
+
+          UBL_has_control_of_LCD_Panel = 0;
+          goto FINE_TUNE_EXIT;
+        }
+      }
+      //UBL_has_control_of_LCD_Panel = 0;
+      delay(20);                       // We don't want any switch noise.
+
+      z_values[location.x_index][location.y_index] = new_z;
+
+      lcd_implementation_clear();
+
+    } while (location.x_index >= 0 && location.y_index >= 0 && --Repetition_Cnt);
+
+    FINE_TUNE_EXIT:
+
+    if (do_UBL_MESH_Map) blm.display_map(1);
+    restore_UBL_active_state_and_leave();
+    do_blocking_move_to_z(Z_CLEARANCE_DEPLOY_PROBE);
+
+    do_blocking_move_to_xy(X_Pos, Y_Pos);
+
+    UBL_has_control_of_LCD_Panel = 0;
+
+    #if ENABLED(ULTRA_LCD)
+      lcd_setstatus("Done Editing Mesh", true);
+    #endif
+    SERIAL_ECHOLNPGM("Done Editing Mesh.");
+  }
+
+#endif // AUTO_BED_LEVELING_UBL
diff --git a/Marlin/UBL_line_to_destination.cpp b/Marlin/UBL_line_to_destination.cpp
new file mode 100644
index 0000000000..bb3956dc38
--- /dev/null
+++ b/Marlin/UBL_line_to_destination.cpp
@@ -0,0 +1,553 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (C) 2016 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * 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/>.
+ *
+ */
+#include "Marlin.h"
+
+#if ENABLED(AUTO_BED_LEVELING_UBL)
+
+  #include "UBL.h"
+  #include "planner.h"
+  #include <avr/io.h>
+  #include <math.h>
+
+  extern void set_current_to_destination();
+  extern bool G26_Debug_flag;
+  void debug_current_and_destination(char *title);
+
+  void wait_for_button_press();
+
+  void UBL_line_to_destination(const float &x_end, const float &y_end, const float &z_end, const float &e_end, const float &feed_rate, uint8_t extruder) {
+
+    int cell_start_xi, cell_start_yi, cell_dest_xi, cell_dest_yi;
+    int left_flag, down_flag;
+    int current_xi, current_yi;
+    int dxi, dyi, xi_cnt, yi_cnt;
+    bool use_X_dist, inf_normalized_flag, inf_m_flag;
+    float x_start, y_start;
+    float x, y, z1, z2, z0 /*, z_optimized */;
+    float next_mesh_line_x, next_mesh_line_y, a0ma1diva2ma1;
+    float on_axis_distance, e_normalized_dist, e_position, e_start, z_normalized_dist, z_position, z_start;
+    float dx, dy, adx, ady, m, c;
+
+    //
+    // Much of the nozzle movement will be within the same cell.  So we will do as little computation
+    // as possible to determine if this is the case.  If this move is within the same cell, we will
+    // just do the required Z-Height correction, call the Planner's buffer_line() routine, and leave
+    //
+
+    x_start = current_position[X_AXIS];
+    y_start = current_position[Y_AXIS];
+    z_start = current_position[Z_AXIS];
+    e_start = current_position[E_AXIS];
+
+    cell_start_xi = blm.get_cell_index_x(x_start);
+    cell_start_yi = blm.get_cell_index_y(y_start);
+    cell_dest_xi  = blm.get_cell_index_x(x_end);
+    cell_dest_yi  = blm.get_cell_index_y(y_end);
+
+    if (G26_Debug_flag!=0) {
+      SERIAL_ECHOPGM(" UBL_line_to_destination(xe=");
+      SERIAL_ECHO(x_end);
+      SERIAL_ECHOPGM(",ye=");
+      SERIAL_ECHO(y_end);
+      SERIAL_ECHOPGM(",ze=");
+      SERIAL_ECHO(z_end);
+      SERIAL_ECHOPGM(",ee=");
+      SERIAL_ECHO(e_end);
+      SERIAL_ECHOPGM(")\n");
+      debug_current_and_destination( (char *) "Start of UBL_line_to_destination()");
+    }
+
+    if ((cell_start_xi == cell_dest_xi) && (cell_start_yi == cell_dest_yi)) { // if the whole move is within the same cell,
+      // we don't need to break up the move
+      //
+      // If we are moving off the print bed, we are going to allow the move at this level.
+      // But we detect it and isolate it.   For now, we just pass along the request.
+      //
+
+      if (cell_dest_xi<0 || cell_dest_yi<0 || cell_dest_xi >= UBL_MESH_NUM_X_POINTS || cell_dest_yi >= UBL_MESH_NUM_Y_POINTS) {
+
+        // Note:  There is no Z Correction in this case.  We are off the grid and don't know what
+        // a reasonable correction would be.
+
+        planner.buffer_line(x_end, y_end, z_end + blm.state.z_offset, e_end, feed_rate, extruder);
+        set_current_to_destination();
+        if (G26_Debug_flag!=0) {
+          debug_current_and_destination( (char *) "out of bounds in UBL_line_to_destination()");
+        }
+        return;
+      }
+
+      // we can optimize some floating point operations here.  We could call float get_z_correction(float x0, float y0) to
+      // generate the correction for us.  But we can lighten the load on the CPU by doing a modified version of the function.
+      // We are going to only calculate the amount we are from the first mesh line towards the second mesh line once.
+      // We will use this fraction in both of the original two Z Height calculations for the bi-linear interpolation.  And,
+      // instead of doing a generic divide of the distance, we know the distance is MESH_X_DIST so we can use the preprocessor
+      // to create a 1-over number for us.  That will allow us to do a floating point multiply instead of a floating point divide.
+
+      FINAL_MOVE:
+      a0ma1diva2ma1 = (x_end - mesh_index_to_X_location[cell_dest_xi]) * (float) (1.0 / MESH_X_DIST);
+
+      z1 = z_values[cell_dest_xi][cell_dest_yi] +
+      (z_values[cell_dest_xi + 1][cell_dest_yi] - z_values[cell_dest_xi][cell_dest_yi]) * a0ma1diva2ma1;
+
+      z2 = z_values[cell_dest_xi][cell_dest_yi+1] +
+      (z_values[cell_dest_xi+1][cell_dest_yi+1] - z_values[cell_dest_xi][cell_dest_yi+1]) * a0ma1diva2ma1;
+
+      // we are done with the fractional X distance into the cell.  Now with the two Z-Heights we have calculated, we
+      // are going to apply the Y-Distance into the cell to interpolate the final Z correction.
+
+      a0ma1diva2ma1 = (y_end - mesh_index_to_Y_location[cell_dest_yi]) * (float) (1.0 / MESH_Y_DIST);
+
+      z0 = z1 + (z2 - z1) * a0ma1diva2ma1;
+
+      // debug code to use non-optimized get_z_correction() and to do a sanity check
+      // that the correct value is being passed to planner.buffer_line()
+      //
+      /*
+        z_optimized = z0;
+        z0 = blm.get_z_correction( x_end, y_end);
+        if ( fabs(z_optimized - z0) > .01 || isnan(z0) || isnan(z_optimized) )  {
+        debug_current_and_destination( (char *) "FINAL_MOVE: z_correction()");
+        if ( isnan(z0) ) SERIAL_ECHO(" z0==NAN  ");
+        if ( isnan(z_optimized) ) SERIAL_ECHO(" z_optimized==NAN  ");
+        SERIAL_ECHOPAIR("  x_end=", x_end);
+        SERIAL_ECHOPAIR("  y_end=", y_end);
+        SERIAL_ECHOPAIR("  z0=", z0);
+        SERIAL_ECHOPAIR("  z_optimized=", z_optimized);
+        SERIAL_ECHOPAIR("  err=",fabs(z_optimized - z0));
+        SERIAL_EOL;
+        }
+      */
+      z0 = z0 * blm.fade_scaling_factor_for_Z( z_end );
+
+      if (isnan(z0)) {  // if part of the Mesh is undefined, it will show up as NAN
+        z0 = 0.0; // in z_values[][] and propagate through the
+        // calculations. If our correction is NAN, we throw it out
+        // because part of the Mesh is undefined and we don't have the
+        // information we need to complete the height correction.
+      }
+
+      planner.buffer_line(x_end, y_end, z_end + z0 + blm.state.z_offset, e_end, feed_rate, extruder);
+      if (G26_Debug_flag!=0) {
+        debug_current_and_destination( (char *) "FINAL_MOVE in UBL_line_to_destination()");
+      }
+      set_current_to_destination();
+      return;
+    }
+
+    //
+    //  If we get here, we are processing a move that crosses at least one Mesh Line.   We will check
+    //  for the simple case of just crossing X or just crossing Y Mesh Lines after we get all the details
+    //  of the move figured out.  We can process the easy case of just crossing an X or Y Mesh Line with less
+    //  computation and in fact most lines are of this nature.  We will check for that in the following
+    //  blocks of code:
+
+    left_flag = 0;
+    down_flag = 0;
+    inf_m_flag = false;
+    inf_normalized_flag = false;
+
+    dx = x_end - x_start;
+    dy = y_end - y_start;
+
+    if (dx<0.0) {     // figure out which way we need to move to get to the next cell
+      dxi = -1;
+      adx = -dx;  // absolute value of dx.  We already need to check if dx and dy are negative.
+    }
+    else {   // We may as well generate the appropriate values for adx and ady right now
+      dxi = 1;  // to save setting up the abs() function call and actually doing the call.
+      adx = dx;
+    }
+    if (dy<0.0) {
+      dyi = -1;
+      ady = -dy;  // absolute value of dy
+    }
+    else {
+      dyi = 1;
+      ady = dy;
+    }
+
+    if (dx<0.0) left_flag = 1;
+    if (dy<0.0) down_flag = 1;
+    if (cell_start_xi == cell_dest_xi) dxi = 0;
+    if (cell_start_yi == cell_dest_yi) dyi = 0;
+
+    //
+    // Compute the scaling factor for the extruder for each partial move.
+    // We need to watch out for zero length moves because it will cause us to
+    // have an infinate scaling factor.  We are stuck doing a floating point
+    // divide to get our scaling factor, but after that, we just multiply by this
+    // number.   We also pick our scaling factor based on whether the X or Y
+    // component is larger.  We use the biggest of the two to preserve precision.
+    //
+    if ( adx > ady ) {
+      use_X_dist = true;
+      on_axis_distance   = x_end-x_start;
+    }
+    else {
+      use_X_dist = false;
+      on_axis_distance   = y_end-y_start;
+    }
+    e_position = e_end - e_start;
+    e_normalized_dist = e_position / on_axis_distance;
+
+    z_position = z_end - z_start;
+    z_normalized_dist = z_position / on_axis_distance;
+
+    if (e_normalized_dist==INFINITY || e_normalized_dist==-INFINITY) {
+      inf_normalized_flag = true;
+    }
+    current_xi = cell_start_xi;
+    current_yi = cell_start_yi;
+
+    m = dy / dx;
+    c = y_start - m*x_start;
+    if (m == INFINITY || m == -INFINITY) {
+      inf_m_flag = true;
+    }
+    //
+    // This block handles vertical lines.  These are lines that stay within the same
+    // X Cell column.  They do not need to be perfectly vertical.  They just can
+    // not cross into another X Cell column.
+    //
+    if (dxi == 0) {       // Check for a vertical line
+      current_yi += down_flag;  // Line is heading down, we just want to go to the bottom
+      while (current_yi != cell_dest_yi + down_flag) {
+        current_yi += dyi;
+        next_mesh_line_y = mesh_index_to_Y_location[current_yi];
+        if (inf_m_flag) {
+          x = x_start;  // if the slope of the line is infinite, we won't do the calculations
+        }
+        // we know the next X is the same so we can recover and continue!
+        else {
+          x = (next_mesh_line_y - c) / m; // Calculate X at the next Y mesh line
+        }
+
+        z0 = blm.get_z_correction_along_horizontal_mesh_line_at_specific_X(x, current_xi, current_yi);
+
+        //
+        // debug code to use non-optimized get_z_correction() and to do a sanity check
+        // that the correct value is being passed to planner.buffer_line()
+        //
+        /*
+          z_optimized = z0;
+          z0 = blm.get_z_correction( x, next_mesh_line_y);
+          if ( fabs(z_optimized - z0) > .01 || isnan(z0) || isnan(z_optimized) )  {
+          debug_current_and_destination( (char *) "VERTICAL z_correction()");
+          if ( isnan(z0) ) SERIAL_ECHO(" z0==NAN  ");
+          if ( isnan(z_optimized) ) SERIAL_ECHO(" z_optimized==NAN  ");
+          SERIAL_ECHOPAIR("  x=", x);
+          SERIAL_ECHOPAIR("  next_mesh_line_y=", next_mesh_line_y);
+          SERIAL_ECHOPAIR("  z0=", z0);
+          SERIAL_ECHOPAIR("  z_optimized=", z_optimized);
+          SERIAL_ECHOPAIR("  err=",fabs(z_optimized-z0));
+          SERIAL_ECHO("\n");
+          }
+        */
+
+        z0 = z0 * blm.fade_scaling_factor_for_Z( z_end );
+
+        if (isnan(z0)) {  // if part of the Mesh is undefined, it will show up as NAN
+          z0 = 0.0; // in z_values[][] and propagate through the
+          // calculations. If our correction is NAN, we throw it out
+          // because part of the Mesh is undefined and we don't have the
+          // information we need to complete the height correction.
+        }
+        y = mesh_index_to_Y_location[current_yi];
+
+        // Without this check, it is possible for the algorythm to generate a zero length move in the case
+        // where the line is heading down and it is starting right on a Mesh Line boundary.  For how often that
+        // happens, it might be best to remove the check and always 'schedule' the move because
+        // the planner.buffer_line() routine will filter it if that happens.
+        if ( y!=y_start)   {
+          if ( inf_normalized_flag == false ) {
+            on_axis_distance   = y - y_start;       // we don't need to check if the extruder position
+            e_position = e_start + on_axis_distance * e_normalized_dist;  // is based on X or Y because this is a vertical move
+            z_position = z_start + on_axis_distance * z_normalized_dist;
+          }
+          else {
+            e_position = e_start;
+            z_position = z_start;
+          }
+
+          planner.buffer_line(x, y, z_position + z0 + blm.state.z_offset, e_position, feed_rate, extruder);
+        } //else printf("FIRST MOVE PRUNED  ");
+      }
+      //
+      // Check if we are at the final destination.  Usually, we won't be, but if it is on a Y Mesh Line, we are done.
+      //
+      if (G26_Debug_flag!=0) {
+        debug_current_and_destination( (char *) "vertical move done in UBL_line_to_destination()");
+      }
+      if (current_position[X_AXIS] != x_end || current_position[Y_AXIS] != y_end) {
+        goto FINAL_MOVE;
+      }
+      set_current_to_destination();
+      return;
+    }
+
+    //
+    // This block handles horizontal lines.  These are lines that stay within the same
+    // Y Cell row.  They do not need to be perfectly horizontal.  They just can
+    // not cross into another Y Cell row.
+    //
+
+    if (dyi == 0) {       // Check for a horiziontal line
+      current_xi += left_flag;  // Line is heading left, we just want to go to the left
+      // edge of this cell for the first move.
+      while (current_xi != cell_dest_xi + left_flag) {
+        current_xi += dxi;
+        next_mesh_line_x = mesh_index_to_X_location[current_xi];
+        y = m * next_mesh_line_x + c;   // Calculate X at the next Y mesh line
+
+        z0 = blm.get_z_correction_along_vertical_mesh_line_at_specific_Y(y, current_xi, current_yi);
+
+        //
+        // debug code to use non-optimized get_z_correction() and to do a sanity check
+        // that the correct value is being passed to planner.buffer_line()
+        //
+        /*
+          z_optimized = z0;
+          z0 = blm.get_z_correction( next_mesh_line_x, y);
+          if ( fabs(z_optimized - z0) > .01 || isnan(z0) || isnan(z_optimized) )  {
+          debug_current_and_destination( (char *) "HORIZONTAL z_correction()");
+          if ( isnan(z0) ) SERIAL_ECHO(" z0==NAN  ");
+          if ( isnan(z_optimized) ) SERIAL_ECHO(" z_optimized==NAN  ");
+          SERIAL_ECHOPAIR("  next_mesh_line_x=", next_mesh_line_x);
+          SERIAL_ECHOPAIR("  y=", y);
+          SERIAL_ECHOPAIR("  z0=", z0);
+          SERIAL_ECHOPAIR("  z_optimized=", z_optimized);
+          SERIAL_ECHOPAIR("  err=",fabs(z_optimized-z0));
+          SERIAL_ECHO("\n");
+          }
+        */
+
+        z0 = z0 * blm.fade_scaling_factor_for_Z( z_end );
+
+        if (isnan(z0)) {  // if part of the Mesh is undefined, it will show up as NAN
+          z0 = 0.0; // in z_values[][] and propagate through the
+          // calculations. If our correction is NAN, we throw it out
+          // because part of the Mesh is undefined and we don't have the
+          // information we need to complete the height correction.
+        }
+        x = mesh_index_to_X_location[current_xi];
+
+        // Without this check, it is possible for the algorythm to generate a zero length move in the case
+        // where the line is heading left and it is starting right on a Mesh Line boundary.  For how often
+        // that happens, it might be best to remove the check and always 'schedule' the move because
+        // the planner.buffer_line() routine will filter it if that happens.
+        if ( x!=x_start)   {
+          if ( inf_normalized_flag == false ) {
+            on_axis_distance   = x - x_start;       // we don't need to check if the extruder position
+            e_position = e_start + on_axis_distance * e_normalized_dist;  // is based on X or Y because this is a horizontal move
+            z_position = z_start + on_axis_distance * z_normalized_dist;
+          }
+          else {
+            e_position = e_start;
+            z_position = z_start;
+          }
+
+          planner.buffer_line(x, y, z_position + z0 + blm.state.z_offset, e_position, feed_rate, extruder);
+        } //else printf("FIRST MOVE PRUNED  ");
+      }
+      if (G26_Debug_flag!=0) {
+        debug_current_and_destination( (char *) "horizontal move done in UBL_line_to_destination()");
+      }
+      if (current_position[X_AXIS] != x_end || current_position[Y_AXIS] != y_end) {
+        goto FINAL_MOVE;
+      }
+      set_current_to_destination();
+      return;
+    }
+
+    //
+    //
+    //
+    //
+    // This block handles the generic case of a line crossing both X and Y
+    // Mesh lines.
+    //
+    //
+    //
+    //
+
+    xi_cnt = cell_start_xi - cell_dest_xi;
+    if ( xi_cnt < 0 ) {
+      xi_cnt = -xi_cnt;
+    }
+
+    yi_cnt = cell_start_yi - cell_dest_yi;
+    if ( yi_cnt < 0 ) {
+      yi_cnt = -yi_cnt;
+    }
+
+    current_xi += left_flag;
+    current_yi += down_flag;
+
+    while ( xi_cnt>0 || yi_cnt>0 )    {
+
+      next_mesh_line_x = mesh_index_to_X_location[current_xi + dxi];
+      next_mesh_line_y = mesh_index_to_Y_location[current_yi + dyi];
+
+      y = m * next_mesh_line_x + c; // Calculate Y at the next X mesh line
+      x = (next_mesh_line_y-c) / m; // Calculate X at the next Y mesh line    (we don't have to worry
+      // about m being equal to 0.0  If this was the case, we would have
+      // detected this as a vertical line move up above and we wouldn't
+      // be down here doing a generic type of move.
+
+      if ((left_flag && (x>next_mesh_line_x)) || (!left_flag && (x<next_mesh_line_x))) { // Check if we hit the Y line first
+        //
+        // Yes!  Crossing a Y Mesh Line next
+        //
+        z0 = blm.get_z_correction_along_horizontal_mesh_line_at_specific_X(x, current_xi-left_flag, current_yi+dyi);
+
+        //
+        // debug code to use non-optimized get_z_correction() and to do a sanity check
+        // that the correct value is being passed to planner.buffer_line()
+        //
+
+        /*
+
+          z_optimized = z0;
+
+          z0 = blm.get_z_correction( x, next_mesh_line_y);
+          if ( fabs(z_optimized - z0) > .01 || isnan(z0) || isnan(z_optimized) )  {
+            debug_current_and_destination( (char *) "General_1: z_correction()");
+            if ( isnan(z0) ) SERIAL_ECHO(" z0==NAN  ");
+            if ( isnan(z_optimized) ) SERIAL_ECHO(" z_optimized==NAN  "); {
+              SERIAL_ECHOPAIR("  x=", x);
+            }
+            SERIAL_ECHOPAIR("  next_mesh_line_y=", next_mesh_line_y);
+            SERIAL_ECHOPAIR("  z0=", z0);
+            SERIAL_ECHOPAIR("  z_optimized=", z_optimized);
+            SERIAL_ECHOPAIR("  err=",fabs(z_optimized-z0));
+            SERIAL_ECHO("\n");
+          }
+        */
+
+        z0 = z0 * blm.fade_scaling_factor_for_Z( z_end );
+        if (isnan(z0)) {  // if part of the Mesh is undefined, it will show up as NAN
+          z0 = 0.0; // in z_values[][] and propagate through the
+          // calculations. If our correction is NAN, we throw it out
+          // because part of the Mesh is undefined and we don't have the
+          // information we need to complete the height correction.
+        }
+
+        if ( inf_normalized_flag == false ) {
+          if ( use_X_dist ) {
+            on_axis_distance   = x - x_start;
+          }
+          else {
+            on_axis_distance   = next_mesh_line_y - y_start;
+          }
+          e_position = e_start + on_axis_distance * e_normalized_dist;
+          z_position = z_start + on_axis_distance * z_normalized_dist;
+        }
+        else {
+          e_position = e_start;
+          z_position = z_start;
+        }
+        planner.buffer_line(x, next_mesh_line_y, z_position + z0 + blm.state.z_offset, e_position, feed_rate, extruder);
+        current_yi += dyi;
+        yi_cnt--;
+      }
+      else {
+        //
+        // Yes!  Crossing a X Mesh Line next
+        //
+        z0 = blm.get_z_correction_along_vertical_mesh_line_at_specific_Y(y, current_xi+dxi, current_yi-down_flag);
+
+
+        //
+        // debug code to use non-optimized get_z_correction() and to do a sanity check
+        // that the correct value is being passed to planner.buffer_line()
+        //
+        /*
+          z_optimized = z0;
+          z0 = blm.get_z_correction( next_mesh_line_x, y);
+          if ( fabs(z_optimized - z0) > .01 || isnan(z0) || isnan(z_optimized) )  {
+          debug_current_and_destination( (char *) "General_2: z_correction()");
+          if ( isnan(z0) ) SERIAL_ECHO(" z0==NAN  ");
+          if ( isnan(z_optimized) ) SERIAL_ECHO(" z_optimized==NAN  ");
+          SERIAL_ECHOPAIR("  next_mesh_line_x=", next_mesh_line_x);
+          SERIAL_ECHOPAIR("  y=", y);
+          SERIAL_ECHOPAIR("  z0=", z0);
+          SERIAL_ECHOPAIR("  z_optimized=", z_optimized);
+          SERIAL_ECHOPAIR("  err=",fabs(z_optimized-z0));
+          SERIAL_ECHO("\n");
+          }
+        */
+
+        z0 = z0 * blm.fade_scaling_factor_for_Z( z_end );
+
+        if (isnan(z0)) {  // if part of the Mesh is undefined, it will show up as NAN
+          z0 = 0.0; // in z_values[][] and propagate through the
+          // calculations. If our correction is NAN, we throw it out
+          // because part of the Mesh is undefined and we don't have the
+          // information we need to complete the height correction.
+        }
+        if ( inf_normalized_flag == false ) {
+          if ( use_X_dist ) {
+            on_axis_distance   = next_mesh_line_x - x_start;
+          }
+          else {
+            on_axis_distance   = y - y_start;
+          }
+          e_position = e_start + on_axis_distance * e_normalized_dist;
+          z_position = z_start + on_axis_distance * z_normalized_dist;
+        }
+        else {
+          e_position = e_start;
+          z_position = z_start;
+        }
+
+        planner.buffer_line(next_mesh_line_x, y, z_position + z0 + blm.state.z_offset, e_position, feed_rate, extruder);
+        current_xi += dxi;
+        xi_cnt--;
+      }
+    }
+    if (G26_Debug_flag) {
+      debug_current_and_destination( (char *) "generic move done in UBL_line_to_destination()");
+    }
+    if (current_position[0] != x_end || current_position[1] != y_end)  {
+      goto FINAL_MOVE;
+    }
+    set_current_to_destination();
+    return;
+  }
+
+  void wait_for_button_press() {
+    //  if ( !been_to_2_6 )
+    //return;   // bob - I think this should be commented out
+
+    SET_INPUT_PULLUP(66); // Roxy's Left Switch is on pin 66.  Right Switch is on pin 65
+    SET_OUTPUT(64);
+    while (READ(66) & 0x01) idle();
+
+    delay(50);
+    while (!(READ(66) & 0x01)) idle();
+    delay(50);
+  }
+
+#endif
+
+
diff --git a/Marlin/hex_print_routines.cpp b/Marlin/hex_print_routines.cpp
new file mode 100644
index 0000000000..19563ccb88
--- /dev/null
+++ b/Marlin/hex_print_routines.cpp
@@ -0,0 +1,47 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (C) 2016 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * 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/>.
+ *
+ */
+
+
+#include "Marlin.h"
+#if ENABLED(AUTO_BED_LEVELING_UBL) || ENABLED(M100_FREE_MEMORY_WATCHER)
+
+#include "hex_print_routines.h"
+
+void prt_hex_nibble(uint8_t n) {
+  if (n <= 9)
+    SERIAL_ECHO(n);
+  else
+    SERIAL_ECHO((char)('A' + n - 10));
+  delay(3);
+}
+
+void prt_hex_byte(uint8_t b) {
+  prt_hex_nibble((b & 0xF0) >> 4);
+  prt_hex_nibble(b & 0x0F);
+}
+
+void prt_hex_word(uint16_t w) {
+  prt_hex_byte((w & 0xFF00) >> 8);
+  prt_hex_byte(w & 0x0FF);
+}
+
+#endif // AUTO_BED_LEVELING_UBL || M100_FREE_MEMORY_WATCHER
diff --git a/Marlin/hex_print_routines.h b/Marlin/hex_print_routines.h
new file mode 100644
index 0000000000..f6b7b28e2c
--- /dev/null
+++ b/Marlin/hex_print_routines.h
@@ -0,0 +1,33 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (C) 2016 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * 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/>.
+ *
+ */
+
+#ifndef HEX_PRINT_ROUTINES_H
+#define HEX_PRINT_ROUTINES_H
+
+//
+// 3 support routines to print hex numbers.  We can print a nibble, byte and word
+//
+void prt_hex_nibble(uint8_t n);
+void prt_hex_byte(uint8_t b);
+void prt_hex_word(uint16_t w);
+
+#endif // HEX_PRINT_ROUTINES_H
\ No newline at end of file
-- 
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