Update ABL comments (PR#95)

* Updates the auto bed leveling comments ONLY.
* Renames "Z probe" word usage in //comments and #errors properly.

Marlin/Configuration.h

 //#define DISABLE_MAX_ENDSTOPS
 //#define DISABLE_MIN_ENDSTOPS
 
-// If you want to enable the Z Probe pin, but disable its use, uncomment the line below.
-// This only affects a Z Probe Endstop if you have separate Z min endstop as well and have
-// activated Z_MIN_PROBE_ENDSTOP below. If you are using the Z Min endstop on your Z Probe,
+// If you want to enable the Z probe pin, but disable its use, uncomment the line below.
+// This only affects a Z probe endstop if you have separate Z min endstop as well and have
+// activated Z_MIN_PROBE_ENDSTOP below. If you are using the Z Min endstop on your Z probe,
 // this has no effect.
 //#define DISABLE_Z_MIN_PROBE_ENDSTOP
 
 //=========================== Manual Bed Leveling ===========================
 //===========================================================================
 
-// #define MANUAL_BED_LEVELING  // Add display menu option for bed leveling
-// #define MESH_BED_LEVELING    // Enable mesh bed leveling
+// #define MANUAL_BED_LEVELING  // Add display menu option for bed leveling.
+// #define MESH_BED_LEVELING    // Enable mesh bed leveling.
 
 #if ENABLED(MANUAL_BED_LEVELING)
-  #define MBL_Z_STEP 0.025  // Step size while manually probing Z axis
+  #define MBL_Z_STEP 0.025  // Step size while manually probing Z axis.
 #endif  // MANUAL_BED_LEVELING
 
 #if ENABLED(MESH_BED_LEVELING)
   #define MESH_MAX_X (X_MAX_POS - MESH_MIN_X)
   #define MESH_MIN_Y 10
   #define MESH_MAX_Y (Y_MAX_POS - MESH_MIN_Y)
-  #define MESH_NUM_X_POINTS 3  // Don't use more than 7 points per axis, implementation limited
+  #define MESH_NUM_X_POINTS 3  // Don't use more than 7 points per axis, implementation limited.
   #define MESH_NUM_Y_POINTS 3
-  #define MESH_HOME_SEARCH_Z 4  // Z after Home, bed somewhere below but above 0.0
+  #define MESH_HOME_SEARCH_Z 4  // Z after Home, bed somewhere below but above 0.0.
 #endif  // MESH_BED_LEVELING
 
 //===========================================================================
 
 // @section bedlevel
 
-//#define ENABLE_AUTO_BED_LEVELING // Delete the comment to enable (remove // at the start of the line)
-#define Z_MIN_PROBE_REPEATABILITY_TEST  // If not commented out, Z-Probe Repeatability test will be included if Auto Bed Leveling is Enabled.
+//#define ENABLE_AUTO_BED_LEVELING // Delete the comment to enable (remove // at the start of the line).
+#define Z_MIN_PROBE_REPEATABILITY_TEST  // If not commented out, Z probe repeatability test will be included if auto bed leveling is enabled.
 
 #if ENABLED(ENABLE_AUTO_BED_LEVELING)
 
-  // There are 2 different ways to specify probing locations
+  // There are 2 different ways to specify probing locations:
   //
   // - "grid" mode
   //   Probe several points in a rectangular grid.
   //   Probe 3 arbitrary points on the bed (that aren't colinear)
   //   You specify the XY coordinates of all 3 points.
 
-  // Enable this to sample the bed in a grid (least squares solution)
-  // Note: this feature generates 10KB extra code size
+  // Enable this to sample the bed in a grid (least squares solution).
+  // Note: this feature generates 10KB extra code size.
   #define AUTO_BED_LEVELING_GRID
 
   #if ENABLED(AUTO_BED_LEVELING_GRID)
     #define FRONT_PROBE_BED_POSITION 20
     #define BACK_PROBE_BED_POSITION 170
 
-    #define MIN_PROBE_EDGE 10 // The probe square sides can be no smaller than this
+    #define MIN_PROBE_EDGE 10 // The Z probe minimum square sides can be no smaller than this.
 
-    // Set the number of grid points per dimension
-    // You probably don't need more than 3 (squared=9)
+    // Set the number of grid points per dimension.
+    // You probably don't need more than 3 (squared=9).
     #define AUTO_BED_LEVELING_GRID_POINTS 2
 
   #else  // !AUTO_BED_LEVELING_GRID
 
-      // Arbitrary points to probe. A simple cross-product
-      // is used to estimate the plane of the bed.
+      // Arbitrary points to probe.
+      // A simple cross-product is used to estimate the plane of the bed.
       #define ABL_PROBE_PT_1_X 15
       #define ABL_PROBE_PT_1_Y 180
       #define ABL_PROBE_PT_2_X 15
 
   #endif // AUTO_BED_LEVELING_GRID
 
-  // Offsets to the probe relative to the extruder tip (Hotend - Probe)
-  // X and Y offsets must be integers
-  #define X_PROBE_OFFSET_FROM_EXTRUDER -25     // Probe on: -left  +right
-  #define Y_PROBE_OFFSET_FROM_EXTRUDER -29     // Probe on: -front +behind
-  #define Z_PROBE_OFFSET_FROM_EXTRUDER -12.35  // -below (always!)
+  // Offsets to the Z probe relative to the nozzle tip.
+  // X and Y offsets must be integers.
+  #define X_PROBE_OFFSET_FROM_EXTRUDER -25     // Z probe to nozzle X offset: -left  +right
+  #define Y_PROBE_OFFSET_FROM_EXTRUDER -29     // Z probe to nozzle Y offset: -front +behind
+  #define Z_PROBE_OFFSET_FROM_EXTRUDER -12.35  // Z probe to nozzle Z offset: -below (always!)
 
-  #define Z_RAISE_BEFORE_HOMING 4       // (in mm) Raise Z before homing (G28) for Probe Clearance.
-                                        // Be sure you have this distance over your Z_MAX_POS in case
+  #define Z_RAISE_BEFORE_HOMING 4       // (in mm) Raise Z axis before homing (G28) for Z probe clearance.
+                                        // Be sure you have this distance over your Z_MAX_POS in case.
 
-  #define XY_TRAVEL_SPEED 8000         // X and Y axis travel speed between probes, in mm/min
+  #define XY_TRAVEL_SPEED 8000         // X and Y axis travel speed between probes, in mm/min.
 
-  #define Z_RAISE_BEFORE_PROBING 15   //How much the extruder will be raised before traveling to the first probing point.
-  #define Z_RAISE_BETWEEN_PROBINGS 5  //How much the extruder will be raised when traveling from between next probing points
-  #define Z_RAISE_AFTER_PROBING 15    //How much the extruder will be raised after the last probing point.
+  #define Z_RAISE_BEFORE_PROBING 15   // How much the Z axis will be raised before traveling to the first probing point.
+  #define Z_RAISE_BETWEEN_PROBINGS 5  // How much the Z axis will be raised when traveling from between next probing points.
+  #define Z_RAISE_AFTER_PROBING 15    // How much the Z axis will be raised after the last probing point.
 
-//   #define Z_PROBE_END_SCRIPT "G1 Z10 F12000\nG1 X15 Y330\nG1 Z0.5\nG1 Z10" //These commands will be executed in the end of G29 routine.
-                                                                            //Useful to retract a deployable probe.
+//   #define Z_PROBE_END_SCRIPT "G1 Z10 F12000\nG1 X15 Y330\nG1 Z0.5\nG1 Z10" // These commands will be executed in the end of G29 routine.
+                                                                            // Useful to retract a deployable Z probe.
 
-  //#define Z_PROBE_SLED // turn on if you have a z-probe mounted on a sled like those designed by Charles Bell
-  //#define SLED_DOCKING_OFFSET 5 // the extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
+  //#define Z_PROBE_SLED // Turn on if you have a Z probe mounted on a sled like those designed by Charles Bell.
+  //#define SLED_DOCKING_OFFSET 5 // The extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
 
-//If you have enabled the Bed Auto Leveling and are using the same Z Probe for Z Homing,
-//it is highly recommended you let this Z_SAFE_HOMING enabled!!!
+// If you have enabled the bed auto leveling and are using the same Z probe for Z homing,
+// it is highly recommended you let this Z_SAFE_HOMING enabled!!!
 
-  #define Z_SAFE_HOMING   // This feature is meant to avoid Z homing with probe outside the bed area.
+  #define Z_SAFE_HOMING   // This feature is meant to avoid Z homing with Z probe outside the bed area.
                           // When defined, it will:
-                          // - Allow Z homing only after X and Y homing AND stepper drivers still enabled
-                          // - If stepper drivers timeout, it will need X and Y homing again before Z homing
-                          // - Position the probe in a defined XY point before Z Homing when homing all axis (G28)
-                          // - Block Z homing only when the probe is outside bed area.
+                          // - Allow Z homing only after X and Y homing AND stepper drivers still enabled.
+                          // - If stepper drivers timeout, it will need X and Y homing again before Z homing.
+                          // - Position the Z probe in a defined XY point before Z Homing when homing all axis (G28).
+                          // - Block Z homing only when the Z probe is outside bed area.
 
   #if ENABLED(Z_SAFE_HOMING)
 
-    #define Z_SAFE_HOMING_X_POINT ((X_MIN_POS + X_MAX_POS) / 2)    // X point for Z homing when homing all axis (G28)
-    #define Z_SAFE_HOMING_Y_POINT ((Y_MIN_POS + Y_MAX_POS) / 2)    // Y point for Z homing when homing all axis (G28)
+    #define Z_SAFE_HOMING_X_POINT ((X_MIN_POS + X_MAX_POS) / 2)    // X point for Z homing when homing all axis (G28).
+    #define Z_SAFE_HOMING_Y_POINT ((Y_MIN_POS + Y_MAX_POS) / 2)    // Y point for Z homing when homing all axis (G28).
 
   #endif
 
-  // Support for a dedicated Z PROBE endstop separate from the Z MIN endstop.
-  // If you would like to use both a Z PROBE and a Z MIN endstop together , uncomment #define Z_MIN_PROBE_ENDSTOP and read the instructions below.
-  // If you want to still use the Z min endstop for homing, disable Z_SAFE_HOMING above. Eg; to park the head outside the bed area when homing with G28.
-  // WARNING: The Z MIN endstop will need to set properly as it would without a Z PROBE to prevent head crashes and premature stopping during a print.
-  // To use a separate Z PROBE endstop, you must have a Z_MIN_PROBE_PIN defined in the pins.h file for your control board.
-  // If you are using a servo based Z PROBE, you will need to enable NUM_SERVOS, Z_ENDSTOP_SERVO_NR and SERVO_ENDSTOP_ANGLES in the R/C Servo below.
-  // RAMPS 1.3/1.4 boards may be able to use the 5V, Ground and the D32 pin in the Aux 4 section of the RAMPS board. Use 5V for powered sensors, otherwise connect to ground and D32
-  // for normally closed configuration and 5V and D32 for normally open configurations. Normally closed configuration is advised and assumed.
-  // The D32 pin in Aux 4 on RAMPS maps to the Arduino D32 pin. Z_MIN_PROBE_PIN is setting the pin to use on the Arduino. Since the D32 pin on the RAMPS maps to D32 on Arduino, this works.
-  // D32 is currently selected in the RAMPS 1.3/1.4 pin file. All other boards will need changes to the respective pins_XXXXX.h file.
-  // WARNING: Setting the wrong pin may have unexpected and potentially disastrous outcomes. Use with caution and do your homework.
-
+  // Support for a dedicated Z probe endstop separate from the Z min endstop.
+  // If you would like to use both a Z probe and a Z min endstop together,
+  // uncomment #define Z_MIN_PROBE_ENDSTOP and read the instructions below.
+  // If you still want to use the Z min endstop for homing, disable Z_SAFE_HOMING above.
+  // Example: To park the head outside the bed area when homing with G28.
+  //
+  // WARNING:
+  // The Z min endstop will need to set properly as it would without a Z probe
+  // to prevent head crashes and premature stopping during a print.
+  //
+  // To use a separate Z probe endstop, you must have a Z_MIN_PROBE_PIN
+  // defined in the pins_XXXXX.h file for your control board.
+  // If you are using a servo based Z probe, you will need to enable NUM_SERVOS,
+  // Z_ENDSTOP_SERVO_NR and SERVO_ENDSTOP_ANGLES in the R/C SERVO support below.
+  // RAMPS 1.3/1.4 boards may be able to use the 5V, Ground and the D32 pin
+  // in the Aux 4 section of the RAMPS board. Use 5V for powered sensors,
+  // otherwise connect to ground and D32 for normally closed configuration
+  // and 5V and D32 for normally open configurations.
+  // Normally closed configuration is advised and assumed.
+  // The D32 pin in Aux 4 on RAMPS maps to the Arduino D32 pin.
+  // Z_MIN_PROBE_PIN is setting the pin to use on the Arduino.
+  // Since the D32 pin on the RAMPS maps to D32 on Arduino, this works.
+  // D32 is currently selected in the RAMPS 1.3/1.4 pin file.
+  // All other boards will need changes to the respective pins_XXXXX.h file.
+  //
+  // WARNING:
+  // Setting the wrong pin may have unexpected and potentially disastrous outcomes.
+  // Use with caution and do your homework.
+  //
   //#define Z_MIN_PROBE_ENDSTOP
 
 #endif // ENABLE_AUTO_BED_LEVELING
 // Servo Endstops
 //
 // This allows for servo actuated endstops, primary usage is for the Z Axis to eliminate calibration or bed height changes.
-// Use M851 to set the z-probe vertical offset from the nozzle. Store that setting with M500.
+// Use M851 to set the Z probe vertical offset from the nozzle. Store that setting with M500.
 //
 //#define X_ENDSTOP_SERVO_NR 1
 //#define Y_ENDSTOP_SERVO_NR 2

Marlin/Marlin_main.cpp

  * G10 - retract filament according to settings of M207
  * G11 - retract recover filament according to settings of M208
  * G28 - Home one or more axes
- * G29 - Detailed Z-Probe, probes the bed at 3 or more points.  Will fail if you haven't homed yet.
- * G30 - Single Z Probe, probes bed at current XY location.
+ * G29 - Detailed Z probe, probes the bed at 3 or more points.  Will fail if you haven't homed yet.
+ * G30 - Single Z probe, probes bed at current XY location.
  * G31 - Dock sled (Z_PROBE_SLED only)
  * G32 - Undock sled (Z_PROBE_SLED only)
  * G90 - Use Absolute Coordinates
  * M380 - Activate solenoid on active extruder
  * M381 - Disable all solenoids
  * M400 - Finish all moves
- * M401 - Lower z-probe if present
- * M402 - Raise z-probe if present
+ * M401 - Lower Z probe if present
+ * M402 - Raise Z probe if present
  * M404 - N<dia in mm> Enter the nominal filament width (3mm, 1.75mm ) or will display nominal filament width without parameters
  * M405 - Turn on Filament Sensor extrusion control.  Optional D<delay in cm> to set delay in centimeters between sensor and extruder
  * M406 - Turn off Filament Sensor extrusion control
  *
  * ************ Custom codes - This can change to suit future G-code regulations
  * M100 - Watch Free Memory (For Debugging Only)
- * M851 - Set probe's Z offset (mm above extruder -- The value will always be negative)
+ * M851 - Set Z probe's Z offset (mm above extruder -- The value will always be negative)
 
 
  * M928 - Start SD logging (M928 filename.g) - ended by M29
       plan_bed_level_matrix.set_to_identity();
       feedrate = homing_feedrate[Z_AXIS];
 
-      // Move down until the probe (or endstop?) is triggered
+      // Move down until the Z probe (or endstop?) is triggered
       float zPosition = -(Z_MAX_LENGTH + 10);
       line_to_z(zPosition);
       st_synchronize();
     #elif ENABLED(Z_PROBE_ALLEN_KEY)
       feedrate = Z_PROBE_ALLEN_KEY_DEPLOY_1_FEEDRATE;
 
-      // If endstop is already false, the probe is deployed
+      // If endstop is already false, the Z probe is deployed
       #if ENABLED(Z_MIN_PROBE_ENDSTOP)
         bool z_probe_endstop = (READ(Z_MIN_PROBE_PIN) != Z_MIN_PROBE_ENDSTOP_INVERTING);
         if (z_probe_endstop)
       destination[Z_AXIS] = Z_PROBE_ALLEN_KEY_STOW_1_Z;
       prepare_move_raw();
 
-      // Move the nozzle down to push the probe into retracted position
+      // Move the nozzle down to push the Z probe into retracted position
       if (Z_PROBE_ALLEN_KEY_STOW_2_FEEDRATE != Z_PROBE_ALLEN_KEY_STOW_1_FEEDRATE) {
         feedrate = Z_PROBE_ALLEN_KEY_STOW_2_FEEDRATE;
       }
 
   // Probe bed height at position (x,y), returns the measured z value
   static float probe_pt(float x, float y, float z_before, ProbeAction probe_action=ProbeDeployAndStow, int verbose_level=1) {
-    // Move Z up to the z_before height, then move the probe to the given XY
+    // Move Z up to the z_before height, then move the Z probe to the given XY
     do_blocking_move_to_z(z_before); // this also updates current_position
     do_blocking_move_to_xy(x - X_PROBE_OFFSET_FROM_EXTRUDER, y - Y_PROBE_OFFSET_FROM_EXTRUDER); // this also updates current_position
 
     
     #if SERVO_LEVELING && DISABLED(Z_PROBE_SLED)
 
-      // Deploy a probe if there is one, and homing towards the bed
+      // Deploy a Z probe if there is one, and homing towards the bed
       if (axis == Z_AXIS) {
         if (axis_home_dir < 0) deploy_z_probe();
       }
     axis_known_position[axis] = true;
 
     #if ENABLED(Z_PROBE_SLED)
-    // bring probe back
+    // bring Z probe back
       if (axis == Z_AXIS) {
         if (axis_home_dir < 0) dock_sled(true);
       } 
 
     #if SERVO_LEVELING && DISABLED(Z_PROBE_SLED)
 
-      // Deploy a probe if there is one, and homing towards the bed
+      // Deploy a Z probe if there is one, and homing towards the bed
       if (axis == Z_AXIS) {
         if (axis_home_dir < 0) stow_z_probe();
       }
             sync_plan_position();
 
             //
-            // Set the probe (or just the nozzle) destination to the safe homing point
+            // Set the Z probe (or just the nozzle) destination to the safe homing point
             //
             // NOTE: If current_position[X_AXIS] or current_position[Y_AXIS] were set above
             // then this may not work as expected.
             // Let's see if X and Y are homed
             if (axis_known_position[X_AXIS] && axis_known_position[Y_AXIS]) {
 
-              // Make sure the probe is within the physical limits
-              // NOTE: This doesn't necessarily ensure the probe is also within the bed!
+              // Make sure the Z probe is within the physical limits
+              // NOTE: This doesn't necessarily ensure the Z probe is also within the bed!
               float cpx = current_position[X_AXIS], cpy = current_position[Y_AXIS];
               if (   cpx >= X_MIN_POS - X_PROBE_OFFSET_FROM_EXTRUDER
                   && cpx <= X_MAX_POS - X_PROBE_OFFSET_FROM_EXTRUDER
   enum MeshLevelingState { MeshReport, MeshStart, MeshNext, MeshSet };
 
   /**
-   * G29: Mesh-based Z-Probe, probes a grid and produces a
+   * G29: Mesh-based Z probe, probes a grid and produces a
    *      mesh to compensate for variable bed height
    *
    * Parameters With MESH_BED_LEVELING:
   }
 
   /**
-   * G29: Detailed Z-Probe, probes the bed at 3 or more points.
+   * G29: Detailed Z probe, probes the bed at 3 or more points.
    *      Will fail if the printer has not been homed with G28.
    *
    * Enhanced G29 Auto Bed Leveling Probe Routine
    *
    * Global Parameters:
    *
-   * E/e By default G29 will engage the probe, test the bed, then disengage.
-   *     Include "E" to engage/disengage the probe for each sample.
-   *     There's no extra effect if you have a fixed probe.
+   * E/e By default G29 will engage the Z probe, test the bed, then disengage.
+   *     Include "E" to engage/disengage the Z probe for each sample.
+   *     There's no extra effect if you have a fixed Z probe.
    *     Usage: "G29 E" or "G29 e"
    *
    */
     #endif // AUTO_BED_LEVELING_GRID
 
     #if ENABLED(Z_PROBE_SLED)
-      dock_sled(false); // engage (un-dock) the probe
+      dock_sled(false); // engage (un-dock) the Z probe
     #elif ENABLED(Z_PROBE_ALLEN_KEY) //|| SERVO_LEVELING
       deploy_z_probe();
     #endif
         plan_bed_level_matrix.debug(" \n\nBed Level Correction Matrix:");
 
       if (!dryrun) {
-        // Correct the Z height difference from z-probe position and hotend tip position.
-        // The Z height on homing is measured by Z-Probe, but the probe is quite far from the hotend.
+        // Correct the Z height difference from Z probe position and nozzle tip position.
+        // The Z height on homing is measured by Z probe, but the Z probe is quite far from the nozzle.
         // When the bed is uneven, this height must be corrected.
         float x_tmp = current_position[X_AXIS] + X_PROBE_OFFSET_FROM_EXTRUDER,
               y_tmp = current_position[Y_AXIS] + Y_PROBE_OFFSET_FROM_EXTRUDER,
               z_tmp = current_position[Z_AXIS],
               real_z = st_get_position_mm(Z_AXIS);  //get the real Z (since plan_get_position is now correcting the plane)
 
-        apply_rotation_xyz(plan_bed_level_matrix, x_tmp, y_tmp, z_tmp); // Apply the correction sending the probe offset
+        apply_rotation_xyz(plan_bed_level_matrix, x_tmp, y_tmp, z_tmp); // Apply the correction sending the Z probe offset
 
         // Get the current Z position and send it to the planner.
         //
         // >> (z_tmp - real_z) : The rotated current Z minus the uncorrected Z (most recent plan_set_position/sync_plan_position)
         //
-        // >> zprobe_zoffset : Z distance from nozzle to probe (set by default, M851, EEPROM, or Menu)
+        // >> zprobe_zoffset : Z distance from nozzle to Z probe (set by default, M851, EEPROM, or Menu)
         //
-        // >> Z_RAISE_AFTER_PROBING : The distance the probe will have lifted after the last probe
+        // >> Z_RAISE_AFTER_PROBING : The distance the Z probe will have lifted after the last probe
         //
         // >> Should home_offset[Z_AXIS] be included?
         //
              + Z_RAISE_AFTER_PROBING
           #endif
           ;
-        // current_position[Z_AXIS] += home_offset[Z_AXIS]; // The probe determines Z=0, not "Z home"
+        // current_position[Z_AXIS] += home_offset[Z_AXIS]; // The Z probe determines Z=0, not "Z home"
         sync_plan_position();
       }
     #endif // !DELTA
 
     #if ENABLED(Z_PROBE_SLED)
-      dock_sled(true); // dock the probe
+      dock_sled(true); // dock the Z probe
     #elif ENABLED(Z_PROBE_ALLEN_KEY) //|| SERVO_LEVELING
       stow_z_probe();
     #endif
   // This is redundant since the SanityCheck.h already checks for a valid Z_MIN_PROBE_PIN, but here for clarity.
   #if ENABLED(Z_MIN_PROBE_ENDSTOP)
     #if !HAS_Z_PROBE
-      #error You must define Z_MIN_PROBE_PIN to enable Z-Probe repeatability calculation.
+      #error You must define Z_MIN_PROBE_PIN to enable Z probe repeatability calculation.
     #endif
   #elif !HAS_Z_MIN
-    #error You must define Z_MIN_PIN to enable Z-Probe repeatability calculation.
+    #error You must define Z_MIN_PIN to enable Z probe repeatability calculation.
   #endif
 
   /**
-   * M48: Z-Probe repeatability measurement function.
+   * M48: Z probe repeatability measurement function.
    *
    * Usage:
    *   M48 <P#> <X#> <Y#> <V#> <E> <L#>
    *     X = Sample X position
    *     Y = Sample Y position
    *     V = Verbose level (0-4, default=1)
-   *     E = Engage probe for each reading
+   *     E = Engage Z probe for each reading
    *     L = Number of legs of movement before probe
    *  
    * This function assumes the bed has been homed.  Specifically, that a G28 command
-   * as been issued prior to invoking the M48 Z-Probe repeatability measurement function.
+   * as been issued prior to invoking the M48 Z probe repeatability measurement function.
    * Any information generated by a prior G29 Bed leveling command will be lost and need to be
    * regenerated.
    */
     }
 
     //
-    // Do all the preliminary setup work.   First raise the probe.
+    // Do all the preliminary setup work.   First raise the Z probe.
     //
 
     st_synchronize();
         break;
 
       #if ENABLED(ENABLE_AUTO_BED_LEVELING) || ENABLED(MESH_BED_LEVELING)
-        case 29: // G29 Detailed Z-Probe, probes the bed at 3 or more points.
+        case 29: // G29 Detailed Z probe, probes the bed at 3 or more points.
           gcode_G29();
           break;
       #endif
 
         #if DISABLED(Z_PROBE_SLED)
 
-          case 30: // G30 Single Z Probe
+          case 30: // G30 Single Z probe
             gcode_G30();
             break;
 
         break;
 
       #if ENABLED(ENABLE_AUTO_BED_LEVELING) && ENABLED(Z_MIN_PROBE_REPEATABILITY_TEST)
-        case 48: // M48 Z-Probe repeatability
+        case 48: // M48 Z probe repeatability
           gcode_M48();
           break;
       #endif // ENABLE_AUTO_BED_LEVELING && Z_MIN_PROBE_REPEATABILITY_TEST

Marlin/SanityCheck.h

   #if ENABLED(ENABLE_AUTO_BED_LEVELING)
 
     /**
-     * Require a Z Min pin
+     * Require a Z min pin
      */
     #if !PIN_EXISTS(Z_MIN)
-      #if !PIN_EXISTS(Z_MIN_PROBE) || (DISABLED(Z_MIN_PROBE_ENDSTOP) || ENABLED(DISABLE_Z_MIN_PROBE_ENDSTOP)) // It's possible for someone to set a pin for the Z Probe, but not enable it.
+      #if !PIN_EXISTS(Z_MIN_PROBE) || (DISABLED(Z_MIN_PROBE_ENDSTOP) || ENABLED(DISABLE_Z_MIN_PROBE_ENDSTOP)) // It's possible for someone to set a pin for the Z probe, but not enable it.
         #if ENABLED(Z_MIN_PROBE_REPEATABILITY_TEST)
-          #error You must have a Z_MIN or Z_PROBE endstop to enable Z_MIN_PROBE_REPEATABILITY_TEST.
+          #error You must have a Z min or Z probe endstop to enable Z_MIN_PROBE_REPEATABILITY_TEST.
         #else
-          #error ENABLE_AUTO_BED_LEVELING requires a Z_MIN or Z_PROBE endstop. Z_MIN_PIN or Z_MIN_PROBE_PIN must point to a valid hardware pin.
+          #error ENABLE_AUTO_BED_LEVELING requires a Z min or Z probe endstop. Z_MIN_PIN or Z_MIN_PROBE_PIN must point to a valid hardware pin.
         #endif
       #endif
     #endif
 
     /**
-     * Require a Z Probe Pin if Z_MIN_PROBE_ENDSTOP is enabled.
+     * Require a Z probe pin if Z_MIN_PROBE_ENDSTOP is enabled.
      */
     #if ENABLED(Z_MIN_PROBE_ENDSTOP)
       #ifndef Z_MIN_PROBE_PIN
         #endif
         // Make sure probing points are reachable
         #if LEFT_PROBE_BED_POSITION < MIN_PROBE_X
-          #error "The given LEFT_PROBE_BED_POSITION can't be reached by the probe."
+          #error "The given LEFT_PROBE_BED_POSITION can't be reached by the Z probe."
         #elif RIGHT_PROBE_BED_POSITION > MAX_PROBE_X
-          #error "The given RIGHT_PROBE_BED_POSITION can't be reached by the probe."
+          #error "The given RIGHT_PROBE_BED_POSITION can't be reached by the Z probe."
         #elif FRONT_PROBE_BED_POSITION < MIN_PROBE_Y
-          #error "The given FRONT_PROBE_BED_POSITION can't be reached by the probe."
+          #error "The given FRONT_PROBE_BED_POSITION can't be reached by the Z probe."
         #elif BACK_PROBE_BED_POSITION > MAX_PROBE_Y
-          #error "The given BACK_PROBE_BED_POSITION can't be reached by the probe."
+          #error "The given BACK_PROBE_BED_POSITION can't be reached by the Z probe."
         #endif
       #endif
     #else // !AUTO_BED_LEVELING_GRID
 
       // Check the triangulation points
       #if ABL_PROBE_PT_1_X < MIN_PROBE_X || ABL_PROBE_PT_1_X > MAX_PROBE_X
-        #error "The given ABL_PROBE_PT_1_X can't be reached by the probe."
+        #error "The given ABL_PROBE_PT_1_X can't be reached by the Z probe."
       #elif ABL_PROBE_PT_2_X < MIN_PROBE_X || ABL_PROBE_PT_2_X > MAX_PROBE_X
-        #error "The given ABL_PROBE_PT_2_X can't be reached by the probe."
+        #error "The given ABL_PROBE_PT_2_X can't be reached by the Z probe."
       #elif ABL_PROBE_PT_3_X < MIN_PROBE_X || ABL_PROBE_PT_3_X > MAX_PROBE_X
-        #error "The given ABL_PROBE_PT_3_X can't be reached by the probe."
+        #error "The given ABL_PROBE_PT_3_X can't be reached by the Z probe."
       #elif ABL_PROBE_PT_1_Y < MIN_PROBE_Y || ABL_PROBE_PT_1_Y > MAX_PROBE_Y
-        #error "The given ABL_PROBE_PT_1_Y can't be reached by the probe."
+        #error "The given ABL_PROBE_PT_1_Y can't be reached by the Z probe."
       #elif ABL_PROBE_PT_2_Y < MIN_PROBE_Y || ABL_PROBE_PT_2_Y > MAX_PROBE_Y
-        #error "The given ABL_PROBE_PT_2_Y can't be reached by the probe."
+        #error "The given ABL_PROBE_PT_2_Y can't be reached by the Z probe."
       #elif ABL_PROBE_PT_3_Y < MIN_PROBE_Y || ABL_PROBE_PT_3_Y > MAX_PROBE_Y
-        #error "The given ABL_PROBE_PT_3_Y can't be reached by the probe."
+        #error "The given ABL_PROBE_PT_3_Y can't be reached by the Z probe."
       #endif
 
     #endif // !AUTO_BED_LEVELING_GRID
   #endif
 
   /**
-   * Allen Key Z Probe requires Auto Bed Leveling grid and Delta
+   * Allen Key Z probe requires Auto Bed Leveling grid and Delta
    */
   #if ENABLED(Z_PROBE_ALLEN_KEY) && !(ENABLED(AUTO_BED_LEVELING_GRID) && ENABLED(DELTA))
     #error Invalid use of Z_PROBE_ALLEN_KEY.

Marlin/configurator/config/Configuration.h

 //#define DISABLE_MAX_ENDSTOPS
 //#define DISABLE_MIN_ENDSTOPS
 
-// If you want to enable the Z Probe pin, but disable its use, uncomment the line below.
-// This only affects a Z Probe Endstop if you have separate Z min endstop as well and have
-// activated Z_MIN_PROBE_ENDSTOP below. If you are using the Z Min endstop on your Z Probe,
+// If you want to enable the Z probe pin, but disable its use, uncomment the line below.
+// This only affects a Z probe endstop if you have separate Z min endstop as well and have
+// activated Z_MIN_PROBE_ENDSTOP below. If you are using the Z Min endstop on your Z probe,
 // this has no effect.
 //#define DISABLE_Z_MIN_PROBE_ENDSTOP
 
 //=========================== Manual Bed Leveling ===========================
 //===========================================================================
 
-// #define MANUAL_BED_LEVELING  // Add display menu option for bed leveling
-// #define MESH_BED_LEVELING    // Enable mesh bed leveling
+// #define MANUAL_BED_LEVELING  // Add display menu option for bed leveling.
+// #define MESH_BED_LEVELING    // Enable mesh bed leveling.
 
 #if ENABLED(MANUAL_BED_LEVELING)
-  #define MBL_Z_STEP 0.025  // Step size while manually probing Z axis
+  #define MBL_Z_STEP 0.025  // Step size while manually probing Z axis.
 #endif  // MANUAL_BED_LEVELING
 
 #if ENABLED(MESH_BED_LEVELING)
   #define MESH_MAX_X (X_MAX_POS - MESH_MIN_X)
   #define MESH_MIN_Y 10
   #define MESH_MAX_Y (Y_MAX_POS - MESH_MIN_Y)
-  #define MESH_NUM_X_POINTS 3  // Don't use more than 7 points per axis, implementation limited
+  #define MESH_NUM_X_POINTS 3  // Don't use more than 7 points per axis, implementation limited.
   #define MESH_NUM_Y_POINTS 3
-  #define MESH_HOME_SEARCH_Z 4  // Z after Home, bed somewhere below but above 0.0
+  #define MESH_HOME_SEARCH_Z 4  // Z after Home, bed somewhere below but above 0.0.
 #endif  // MESH_BED_LEVELING
 
 //===========================================================================
 
 // @section bedlevel
 
-//#define ENABLE_AUTO_BED_LEVELING // Delete the comment to enable (remove // at the start of the line)
-#define Z_MIN_PROBE_REPEATABILITY_TEST  // If not commented out, Z-Probe Repeatability test will be included if Auto Bed Leveling is Enabled.
+//#define ENABLE_AUTO_BED_LEVELING // Delete the comment to enable (remove // at the start of the line).
+#define Z_MIN_PROBE_REPEATABILITY_TEST  // If not commented out, Z probe repeatability test will be included if auto bed leveling is enabled.
 
 #if ENABLED(ENABLE_AUTO_BED_LEVELING)
 
-  // There are 2 different ways to specify probing locations
+  // There are 2 different ways to specify probing locations:
   //
   // - "grid" mode
   //   Probe several points in a rectangular grid.
   //   Probe 3 arbitrary points on the bed (that aren't colinear)
   //   You specify the XY coordinates of all 3 points.
 
-  // Enable this to sample the bed in a grid (least squares solution)
-  // Note: this feature generates 10KB extra code size
+  // Enable this to sample the bed in a grid (least squares solution).
+  // Note: this feature generates 10KB extra code size.
   #define AUTO_BED_LEVELING_GRID
 
   #if ENABLED(AUTO_BED_LEVELING_GRID)
     #define FRONT_PROBE_BED_POSITION 20
     #define BACK_PROBE_BED_POSITION 170
 
-    #define MIN_PROBE_EDGE 10 // The probe square sides can be no smaller than this
+    #define MIN_PROBE_EDGE 10 // The Z probe square sides can be no smaller than this.
 
-    // Set the number of grid points per dimension
-    // You probably don't need more than 3 (squared=9)
+    // Set the number of grid points per dimension.
+    // You probably don't need more than 3 (squared=9).
     #define AUTO_BED_LEVELING_GRID_POINTS 2
 
   #else  // !AUTO_BED_LEVELING_GRID
 
-      // Arbitrary points to probe. A simple cross-product
-      // is used to estimate the plane of the bed.
+      // Arbitrary points to probe.
+      // A simple cross-product is used to estimate the plane of the bed.
       #define ABL_PROBE_PT_1_X 15
       #define ABL_PROBE_PT_1_Y 180
       #define ABL_PROBE_PT_2_X 15
 
   #endif // AUTO_BED_LEVELING_GRID
 
-  // Offsets to the probe relative to the extruder tip (Hotend - Probe)
-  // X and Y offsets must be integers
-  #define X_PROBE_OFFSET_FROM_EXTRUDER -25     // Probe on: -left  +right
-  #define Y_PROBE_OFFSET_FROM_EXTRUDER -29     // Probe on: -front +behind
-  #define Z_PROBE_OFFSET_FROM_EXTRUDER -12.35  // -below (always!)
+  // Offsets to the Z probe relative to the nozzle tip.
+  // X and Y offsets must be integers.
+  #define X_PROBE_OFFSET_FROM_EXTRUDER -25     // Z probe to nozzle X offset: -left  +right
+  #define Y_PROBE_OFFSET_FROM_EXTRUDER -29     // Z probe to nozzle Y offset: -front +behind
+  #define Z_PROBE_OFFSET_FROM_EXTRUDER -12.35  // Z probe to nozzle Z offset: -below (always!)
 
-  #define Z_RAISE_BEFORE_HOMING 4       // (in mm) Raise Z before homing (G28) for Probe Clearance.
-                                        // Be sure you have this distance over your Z_MAX_POS in case
+  #define Z_RAISE_BEFORE_HOMING 4       // (in mm) Raise Z axis before homing (G28) for Z probe clearance.
+                                        // Be sure you have this distance over your Z_MAX_POS in case.
 
-  #define XY_TRAVEL_SPEED 8000         // X and Y axis travel speed between probes, in mm/min
+  #define XY_TRAVEL_SPEED 8000         // X and Y axis travel speed between probes, in mm/min.
 
-  #define Z_RAISE_BEFORE_PROBING 15   //How much the extruder will be raised before traveling to the first probing point.
-  #define Z_RAISE_BETWEEN_PROBINGS 5  //How much the extruder will be raised when traveling from between next probing points
-  #define Z_RAISE_AFTER_PROBING 15    //How much the extruder will be raised after the last probing point.
+  #define Z_RAISE_BEFORE_PROBING 15   // How much the Z axis will be raised before traveling to the first probing point.
+  #define Z_RAISE_BETWEEN_PROBINGS 5  // How much the Z axis will be raised when traveling from between next probing points.
+  #define Z_RAISE_AFTER_PROBING 15    // How much the Z axis will be raised after the last probing point.
 
-//   #define Z_PROBE_END_SCRIPT "G1 Z10 F12000\nG1 X15 Y330\nG1 Z0.5\nG1 Z10" //These commands will be executed in the end of G29 routine.
-                                                                            //Useful to retract a deployable probe.
+//   #define Z_PROBE_END_SCRIPT "G1 Z10 F12000\nG1 X15 Y330\nG1 Z0.5\nG1 Z10" // These commands will be executed in the end of G29 routine.
+                                                                            // Useful to retract a deployable Z probe.
 
-  //#define Z_PROBE_SLED // turn on if you have a z-probe mounted on a sled like those designed by Charles Bell
-  //#define SLED_DOCKING_OFFSET 5 // the extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
+  //#define Z_PROBE_SLED // Turn on if you have a Z probe mounted on a sled like those designed by Charles Bell.
+  //#define SLED_DOCKING_OFFSET 5 // The extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
 
-//If you have enabled the Bed Auto Leveling and are using the same Z Probe for Z Homing,
-//it is highly recommended you let this Z_SAFE_HOMING enabled!!!
+// If you have enabled the bed auto leveling and are using the same Z probe for Z homing,
+// it is highly recommended you let this Z_SAFE_HOMING enabled!!!
 
-  #define Z_SAFE_HOMING   // This feature is meant to avoid Z homing with probe outside the bed area.
+  #define Z_SAFE_HOMING   // This feature is meant to avoid Z homing with Z probe outside the bed area.
                           // When defined, it will:
-                          // - Allow Z homing only after X and Y homing AND stepper drivers still enabled
-                          // - If stepper drivers timeout, it will need X and Y homing again before Z homing
-                          // - Position the probe in a defined XY point before Z Homing when homing all axis (G28)
-                          // - Block Z homing only when the probe is outside bed area.
+                          // - Allow Z homing only after X and Y homing AND stepper drivers still enabled.
+                          // - If stepper drivers timeout, it will need X and Y homing again before Z homing.
+                          // - Position the Z probe in a defined XY point before Z Homing when homing all axis (G28).
+                          // - Block Z homing only when the Z probe is outside bed area.
 
   #if ENABLED(Z_SAFE_HOMING)
 
-    #define Z_SAFE_HOMING_X_POINT ((X_MIN_POS + X_MAX_POS) / 2)    // X point for Z homing when homing all axis (G28)
-    #define Z_SAFE_HOMING_Y_POINT ((Y_MIN_POS + Y_MAX_POS) / 2)    // Y point for Z homing when homing all axis (G28)
+    #define Z_SAFE_HOMING_X_POINT ((X_MIN_POS + X_MAX_POS) / 2)    // X point for Z homing when homing all axis (G28).
+    #define Z_SAFE_HOMING_Y_POINT ((Y_MIN_POS + Y_MAX_POS) / 2)    // Y point for Z homing when homing all axis (G28).
 
   #endif
 
-  // Support for a dedicated Z PROBE endstop separate from the Z MIN endstop.
-  // If you would like to use both a Z PROBE and a Z MIN endstop together , uncomment #define Z_MIN_PROBE_ENDSTOP and read the instructions below.
-  // If you want to still use the Z min endstop for homing, disable Z_SAFE_HOMING above. Eg; to park the head outside the bed area when homing with G28.
-  // WARNING: The Z MIN endstop will need to set properly as it would without a Z PROBE to prevent head crashes and premature stopping during a print.
-  // To use a separate Z PROBE endstop, you must have a Z_MIN_PROBE_PIN defined in the pins.h file for your control board.
-  // If you are using a servo based Z PROBE, you will need to enable NUM_SERVOS, Z_ENDSTOP_SERVO_NR and SERVO_ENDSTOP_ANGLES in the R/C Servo below.
-  // RAMPS 1.3/1.4 boards may be able to use the 5V, Ground and the D32 pin in the Aux 4 section of the RAMPS board. Use 5V for powered sensors, otherwise connect to ground and D32
-  // for normally closed configuration and 5V and D32 for normally open configurations. Normally closed configuration is advised and assumed.
-  // The D32 pin in Aux 4 on RAMPS maps to the Arduino D32 pin. Z_MIN_PROBE_PIN is setting the pin to use on the Arduino. Since the D32 pin on the RAMPS maps to D32 on Arduino, this works.
-  // D32 is currently selected in the RAMPS 1.3/1.4 pin file. All other boards will need changes to the respective pins_XXXXX.h file.
-  // WARNING: Setting the wrong pin may have unexpected and potentially disastrous outcomes. Use with caution and do your homework.
-
+  // Support for a dedicated Z probe endstop separate from the Z min endstop.
+  // If you would like to use both a Z probe and a Z min endstop together,
+  // uncomment #define Z_MIN_PROBE_ENDSTOP and read the instructions below.
+  // If you still want to use the Z min endstop for homing, disable Z_SAFE_HOMING above.
+  // Example: To park the head outside the bed area when homing with G28.
+  //
+  // WARNING:
+  // The Z min endstop will need to set properly as it would without a Z probe
+  // to prevent head crashes and premature stopping during a print.
+  //
+  // To use a separate Z probe endstop, you must have a Z_MIN_PROBE_PIN
+  // defined in the pins_XXXXX.h file for your control board.
+  // If you are using a servo based Z probe, you will need to enable NUM_SERVOS,
+  // Z_ENDSTOP_SERVO_NR and SERVO_ENDSTOP_ANGLES in the R/C SERVO support below.
+  // RAMPS 1.3/1.4 boards may be able to use the 5V, Ground and the D32 pin
+  // in the Aux 4 section of the RAMPS board. Use 5V for powered sensors,
+  // otherwise connect to ground and D32 for normally closed configuration
+  // and 5V and D32 for normally open configurations.
+  // Normally closed configuration is advised and assumed.
+  // The D32 pin in Aux 4 on RAMPS maps to the Arduino D32 pin.
+  // Z_MIN_PROBE_PIN is setting the pin to use on the Arduino.
+  // Since the D32 pin on the RAMPS maps to D32 on Arduino, this works.
+  // D32 is currently selected in the RAMPS 1.3/1.4 pin file.
+  // All other boards will need changes to the respective pins_XXXXX.h file.
+  //
+  // WARNING:
+  // Setting the wrong pin may have unexpected and potentially disastrous outcomes.
+  // Use with caution and do your homework.
+  //
   //#define Z_MIN_PROBE_ENDSTOP
 
 #endif // ENABLE_AUTO_BED_LEVELING
 // Servo Endstops
 //
 // This allows for servo actuated endstops, primary usage is for the Z Axis to eliminate calibration or bed height changes.
-// Use M851 to set the z-probe vertical offset from the nozzle. Store that setting with M500.
+// Use M851 to set the Z probe vertical offset from the nozzle. Store that setting with M500.
 //
 //#define X_ENDSTOP_SERVO_NR 1
 //#define Y_ENDSTOP_SERVO_NR 2

Marlin/example_configurations/Felix/Configuration.h

 #define DISABLE_MAX_ENDSTOPS
 //#define DISABLE_MIN_ENDSTOPS
 
-// If you want to enable the Z Probe pin, but disable its use, uncomment the line below.
-// This only affects a Z Probe Endstop if you have separate Z min endstop as well and have
-// activated Z_MIN_PROBE_ENDSTOP below. If you are using the Z Min endstop on your Z Probe,
+// If you want to enable the Z probe pin, but disable its use, uncomment the line below.
+// This only affects a Z probe endstop if you have separate Z min endstop as well and have
+// activated Z_MIN_PROBE_ENDSTOP below. If you are using the Z Min endstop on your Z probe,
 // this has no effect.
 //#define DISABLE_Z_MIN_PROBE_ENDSTOP
 
 //=========================== Manual Bed Leveling ===========================
 //===========================================================================
 
-// #define MANUAL_BED_LEVELING  // Add display menu option for bed leveling
-// #define MESH_BED_LEVELING    // Enable mesh bed leveling
+// #define MANUAL_BED_LEVELING  // Add display menu option for bed leveling.
+// #define MESH_BED_LEVELING    // Enable mesh bed leveling.
 
 #if ENABLED(MANUAL_BED_LEVELING)
-  #define MBL_Z_STEP 0.025  // Step size while manually probing Z axis
+  #define MBL_Z_STEP 0.025  // Step size while manually probing Z axis.
 #endif  // MANUAL_BED_LEVELING
 
 #if ENABLED(MESH_BED_LEVELING)
   #define MESH_MAX_X (X_MAX_POS - MESH_MIN_X)
   #define MESH_MIN_Y 10
   #define MESH_MAX_Y (Y_MAX_POS - MESH_MIN_Y)
-  #define MESH_NUM_X_POINTS 3  // Don't use more than 7 points per axis, implementation limited
+  #define MESH_NUM_X_POINTS 3  // Don't use more than 7 points per axis, implementation limited.
   #define MESH_NUM_Y_POINTS 3
-  #define MESH_HOME_SEARCH_Z 4  // Z after Home, bed somewhere below but above 0.0
+  #define MESH_HOME_SEARCH_Z 4  // Z after Home, bed somewhere below but above 0.0.
 #endif  // MESH_BED_LEVELING
 
 //===========================================================================
 
 // @section bedlevel
 
-//#define ENABLE_AUTO_BED_LEVELING // Delete the comment to enable (remove // at the start of the line)
-//#define Z_MIN_PROBE_REPEATABILITY_TEST  // If not commented out, Z-Probe Repeatability test will be included if Auto Bed Leveling is Enabled.
+//#define ENABLE_AUTO_BED_LEVELING // Delete the comment to enable (remove // at the start of the line).
+//#define Z_MIN_PROBE_REPEATABILITY_TEST  // If not commented out, Z probe repeatability test will be included if auto bed leveling is enabled.
 
 #if ENABLED(ENABLE_AUTO_BED_LEVELING)
 
-  // There are 2 different ways to specify probing locations
+  // There are 2 different ways to specify probing locations:
   //
   // - "grid" mode
   //   Probe several points in a rectangular grid.
   //   Probe 3 arbitrary points on the bed (that aren't colinear)
   //   You specify the XY coordinates of all 3 points.
 
-  // Enable this to sample the bed in a grid (least squares solution)
-  // Note: this feature generates 10KB extra code size
+  // Enable this to sample the bed in a grid (least squares solution).
+  // Note: this feature generates 10KB extra code size.
   #define AUTO_BED_LEVELING_GRID
 
   #if ENABLED(AUTO_BED_LEVELING_GRID)
     #define FRONT_PROBE_BED_POSITION 20
     #define BACK_PROBE_BED_POSITION 180
 
-    #define MIN_PROBE_EDGE 10 // The probe square sides can be no smaller than this
+    #define MIN_PROBE_EDGE 10 // The Z probe square sides can be no smaller than this.
 
-    // Set the number of grid points per dimension
-    // You probably don't need more than 3 (squared=9)
+    // Set the number of grid points per dimension.
+    // You probably don't need more than 3 (squared=9).
     #define AUTO_BED_LEVELING_GRID_POINTS 2
 
   #else  // !AUTO_BED_LEVELING_GRID
 
-      // Arbitrary points to probe. A simple cross-product
-      // is used to estimate the plane of the bed.
+      // Arbitrary points to probe.
+      // A simple cross-product is used to estimate the plane of the bed.
       #define ABL_PROBE_PT_1_X 15
       #define ABL_PROBE_PT_1_Y 180
       #define ABL_PROBE_PT_2_X 15
 
   #endif // AUTO_BED_LEVELING_GRID
 
-  // Offsets to the probe relative to the extruder tip (Hotend - Probe)
-  // X and Y offsets must be integers
-  #define X_PROBE_OFFSET_FROM_EXTRUDER -25     // Probe on: -left  +right
-  #define Y_PROBE_OFFSET_FROM_EXTRUDER -29     // Probe on: -front +behind
-  #define Z_PROBE_OFFSET_FROM_EXTRUDER -12.35  // -below (always!)
+  // Offsets to the Z probe relative to the nozzle tip.
+  // X and Y offsets must be integers.
+  #define X_PROBE_OFFSET_FROM_EXTRUDER -25     // Z probe to nozzle X offset: -left  +right
+  #define Y_PROBE_OFFSET_FROM_EXTRUDER -29     // Z probe to nozzle Y offset: -front +behind
+  #define Z_PROBE_OFFSET_FROM_EXTRUDER -12.35  // Z probe to nozzle Z offset: -below (always!)
 
-  #define Z_RAISE_BEFORE_HOMING 4       // (in mm) Raise Z before homing (G28) for Probe Clearance.
-                                        // Be sure you have this distance over your Z_MAX_POS in case
+  #define Z_RAISE_BEFORE_HOMING 4       // (in mm) Raise Z axis before homing (G28) for Z probe clearance.
+                                        // Be sure you have this distance over your Z_MAX_POS in case.
 
-  #define XY_TRAVEL_SPEED 8000         // X and Y axis travel speed between probes, in mm/min
+  #define XY_TRAVEL_SPEED 8000         // X and Y axis travel speed between probes, in mm/min.
 
-  #define Z_RAISE_BEFORE_PROBING 15   //How much the extruder will be raised before traveling to the first probing point.
-  #define Z_RAISE_BETWEEN_PROBINGS 5  //How much the extruder will be raised when traveling from between next probing points
-  #define Z_RAISE_AFTER_PROBING 15    //How much the extruder will be raised after the last probing point.
+  #define Z_RAISE_BEFORE_PROBING 15   // How much the Z axis will be raised before traveling to the first probing point.
+  #define Z_RAISE_BETWEEN_PROBINGS 5  // How much the Z axis will be raised when traveling from between next probing points.
+  #define Z_RAISE_AFTER_PROBING 15    // How much the Z axis will be raised after the last probing point.
 
-//   #define Z_PROBE_END_SCRIPT "G1 Z10 F12000\nG1 X15 Y330\nG1 Z0.5\nG1 Z10" //These commands will be executed in the end of G29 routine.
-                                                                            //Useful to retract a deployable probe.
+//   #define Z_PROBE_END_SCRIPT "G1 Z10 F12000\nG1 X15 Y330\nG1 Z0.5\nG1 Z10" // These commands will be executed in the end of G29 routine.
+                                                                            // Useful to retract a deployable Z probe.
 
-  //#define Z_PROBE_SLED // turn on if you have a z-probe mounted on a sled like those designed by Charles Bell
-  //#define SLED_DOCKING_OFFSET 5 // the extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
+  //#define Z_PROBE_SLED // Turn on if you have a Z probe mounted on a sled like those designed by Charles Bell.
+  //#define SLED_DOCKING_OFFSET 5 // The extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
 
-//If you have enabled the Bed Auto Leveling and are using the same Z Probe for Z Homing,
-//it is highly recommended you let this Z_SAFE_HOMING enabled!!!
+// If you have enabled the bed auto leveling and are using the same Z probe for Z homing,
+// it is highly recommended you let this Z_SAFE_HOMING enabled!!!
 
-  #define Z_SAFE_HOMING   // This feature is meant to avoid Z homing with probe outside the bed area.
+  #define Z_SAFE_HOMING   // This feature is meant to avoid Z homing with Z probe outside the bed area.
                           // When defined, it will:
-                          // - Allow Z homing only after X and Y homing AND stepper drivers still enabled
-                          // - If stepper drivers timeout, it will need X and Y homing again before Z homing
-                          // - Position the probe in a defined XY point before Z Homing when homing all axis (G28)
-                          // - Block Z homing only when the probe is outside bed area.
+                          // - Allow Z homing only after X and Y homing AND stepper drivers still enabled.
+                          // - If stepper drivers timeout, it will need X and Y homing again before Z homing.
+                          // - Position the Z probe in a defined XY point before Z Homing when homing all axis (G28).
+                          // - Block Z homing only when the Z probe is outside bed area.
 
   #if ENABLED(Z_SAFE_HOMING)
 
-    #define Z_SAFE_HOMING_X_POINT ((X_MIN_POS + X_MAX_POS) / 2)    // X point for Z homing when homing all axis (G28)
-    #define Z_SAFE_HOMING_Y_POINT ((Y_MIN_POS + Y_MAX_POS) / 2)    // Y point for Z homing when homing all axis (G28)
+    #define Z_SAFE_HOMING_X_POINT ((X_MIN_POS + X_MAX_POS) / 2)    // X point for Z homing when homing all axis (G28).
+    #define Z_SAFE_HOMING_Y_POINT ((Y_MIN_POS + Y_MAX_POS) / 2)    // Y point for Z homing when homing all axis (G28).
 
   #endif
 
-  // Support for a dedicated Z PROBE endstop separate from the Z MIN endstop.
-  // If you would like to use both a Z PROBE and a Z MIN endstop together , uncomment #define Z_MIN_PROBE_ENDSTOP and read the instructions below.
-  // If you want to still use the Z min endstop for homing, disable Z_SAFE_HOMING above. Eg; to park the head outside the bed area when homing with G28.
-  // WARNING: The Z MIN endstop will need to set properly as it would without a Z PROBE to prevent head crashes and premature stopping during a print.
-  // To use a separate Z PROBE endstop, you must have a Z_MIN_PROBE_PIN defined in the pins.h file for your control board.
-  // If you are using a servo based Z PROBE, you will need to enable NUM_SERVOS, Z_ENDSTOP_SERVO_NR and SERVO_ENDSTOP_ANGLES in the R/C Servo below.
-  // RAMPS 1.3/1.4 boards may be able to use the 5V, Ground and the D32 pin in the Aux 4 section of the RAMPS board. Use 5V for powered sensors, otherwise connect to ground and D32
-  // for normally closed configuration and 5V and D32 for normally open configurations. Normally closed configuration is advised and assumed.
-  // The D32 pin in Aux 4 on RAMPS maps to the Arduino D32 pin. Z_MIN_PROBE_PIN is setting the pin to use on the Arduino. Since the D32 pin on the RAMPS maps to D32 on Arduino, this works.
-  // D32 is currently selected in the RAMPS 1.3/1.4 pin file. All other boards will need changes to the respective pins_XXXXX.h file.
-  // WARNING: Setting the wrong pin may have unexpected and potentially disastrous outcomes. Use with caution and do your homework.
-
+  // Support for a dedicated Z probe endstop separate from the Z min endstop.
+  // If you would like to use both a Z probe and a Z min endstop together,
+  // uncomment #define Z_MIN_PROBE_ENDSTOP and read the instructions below.
+  // If you still want to use the Z min endstop for homing, disable Z_SAFE_HOMING above.
+  // Example: To park the head outside the bed area when homing with G28.
+  //
+  // WARNING:
+  // The Z min endstop will need to set properly as it would without a Z probe
+  // to prevent head crashes and premature stopping during a print.
+  //
+  // To use a separate Z probe endstop, you must have a Z_MIN_PROBE_PIN
+  // defined in the pins_XXXXX.h file for your control board.
+  // If you are using a servo based Z probe, you will need to enable NUM_SERVOS,
+  // Z_ENDSTOP_SERVO_NR and SERVO_ENDSTOP_ANGLES in the R/C SERVO support below.
+  // RAMPS 1.3/1.4 boards may be able to use the 5V, Ground and the D32 pin
+  // in the Aux 4 section of the RAMPS board. Use 5V for powered sensors,
+  // otherwise connect to ground and D32 for normally closed configuration
+  // and 5V and D32 for normally open configurations.
+  // Normally closed configuration is advised and assumed.
+  // The D32 pin in Aux 4 on RAMPS maps to the Arduino D32 pin.
+  // Z_MIN_PROBE_PIN is setting the pin to use on the Arduino.
+  // Since the D32 pin on the RAMPS maps to D32 on Arduino, this works.
+  // D32 is currently selected in the RAMPS 1.3/1.4 pin file.
+  // All other boards will need changes to the respective pins_XXXXX.h file.
+  //
+  // WARNING:
+  // Setting the wrong pin may have unexpected and potentially disastrous outcomes.
+  // Use with caution and do your homework.
+  //
   //#define Z_MIN_PROBE_ENDSTOP
 
 #endif // ENABLE_AUTO_BED_LEVELING
   #define EEPROM_CHITCHAT // Please keep turned on if you can.
 #endif
 
+//
+// M100 Free Memory Watcher
+//
+//#define M100_FREE_MEMORY_WATCHER // uncomment to add the M100 Free Memory Watcher for debug purpose
+
 // @section temperature
 
 // Preheat Constants
 // Servo Endstops
 //
 // This allows for servo actuated endstops, primary usage is for the Z Axis to eliminate calibration or bed height changes.
-// Use M851 to set the z-probe vertical offset from the nozzle. Store that setting with M500.
+// Use M851 to set the Z probe vertical offset from the nozzle. Store that setting with M500.
 //
 //#define X_ENDSTOP_SERVO_NR 1
 //#define Y_ENDSTOP_SERVO_NR 2

Marlin/example_configurations/Felix/Configuration_DUAL.h

 #define DISABLE_MAX_ENDSTOPS
 //#define DISABLE_MIN_ENDSTOPS
 
+// If you want to enable the Z probe pin, but disable its use, uncomment the line below.
+// This only affects a Z probe endstop if you have separate Z min endstop as well and have
+// activated Z_MIN_PROBE_ENDSTOP below. If you are using the Z Min endstop on your Z probe,
+// this has no effect.
+//#define DISABLE_Z_MIN_PROBE_ENDSTOP
+
 // For Inverting Stepper Enable Pins (Active Low) use 0, Non Inverting (Active High) use 1
 #define X_ENABLE_ON 0
 #define Y_ENABLE_ON 0
 //=========================== Manual Bed Leveling ===========================
 //===========================================================================
 
-// #define MANUAL_BED_LEVELING  // Add display menu option for bed leveling
-// #define MESH_BED_LEVELING    // Enable mesh bed leveling
+// #define MANUAL_BED_LEVELING  // Add display menu option for bed leveling.
+// #define MESH_BED_LEVELING    // Enable mesh bed leveling.
+
+#if ENABLED(MANUAL_BED_LEVELING)
+  #define MBL_Z_STEP 0.025  // Step size while manually probing Z axis.
+#endif  // MANUAL_BED_LEVELING
 
 #if ENABLED(MESH_BED_LEVELING)
   #define MESH_MIN_X 10
   #define MESH_MAX_X (X_MAX_POS - MESH_MIN_X)
   #define MESH_MIN_Y 10
   #define MESH_MAX_Y (Y_MAX_POS - MESH_MIN_Y)
-  #define MESH_NUM_X_POINTS 3  // Don't use more than 7 points per axis, implementation limited
+  #define MESH_NUM_X_POINTS 3  // Don't use more than 7 points per axis, implementation limited.
   #define MESH_NUM_Y_POINTS 3
-  #define MESH_HOME_SEARCH_Z 4  // Z after Home, bed somewhere below but above 0.0
+  #define MESH_HOME_SEARCH_Z 4  // Z after Home, bed somewhere below but above 0.0.
 #endif  // MESH_BED_LEVELING
 
 //===========================================================================
 //============================ Bed Auto Leveling ============================
 //===========================================================================
 
-//#define ENABLE_AUTO_BED_LEVELING // Delete the comment to enable (remove // at the start of the line)
-//#define Z_MIN_PROBE_REPEATABILITY_TEST  // If not commented out, Z-Probe Repeatability test will be included if Auto Bed Leveling is Enabled.
+// @section bedlevel
+
+//#define ENABLE_AUTO_BED_LEVELING // Delete the comment to enable (remove // at the start of the line).
+//#define Z_MIN_PROBE_REPEATABILITY_TEST  // If not commented out, Z probe repeatability test will be included if auto bed leveling is enabled.
 
 #if ENABLED(ENABLE_AUTO_BED_LEVELING)
 
-  // There are 2 different ways to specify probing locations
+  // There are 2 different ways to specify probing locations:
   //
   // - "grid" mode
   //   Probe several points in a rectangular grid.
   //   Probe 3 arbitrary points on the bed (that aren't colinear)
   //   You specify the XY coordinates of all 3 points.
 
-  // Enable this to sample the bed in a grid (least squares solution)
-  // Note: this feature generates 10KB extra code size
+  // Enable this to sample the bed in a grid (least squares solution).
+  // Note: this feature generates 10KB extra code size.
   #define AUTO_BED_LEVELING_GRID
 
   #if ENABLED(AUTO_BED_LEVELING_GRID)
     #define FRONT_PROBE_BED_POSITION 20
     #define BACK_PROBE_BED_POSITION 180
 
-    #define MIN_PROBE_EDGE 10 // The probe square sides can be no smaller than this      
+    #define MIN_PROBE_EDGE 10 // The Z probe square sides can be no smaller than this.
 
-    // Set the number of grid points per dimension
-    // You probably don't need more than 3 (squared=9)
+    // Set the number of grid points per dimension.
+    // You probably don't need more than 3 (squared=9).
     #define AUTO_BED_LEVELING_GRID_POINTS 2
 
   #else  // !AUTO_BED_LEVELING_GRID
 
-      // Arbitrary points to probe. A simple cross-product
-      // is used to estimate the plane of the bed.
+      // Arbitrary points to probe.
+      // A simple cross-product is used to estimate the plane of the bed.
       #define ABL_PROBE_PT_1_X 15
       #define ABL_PROBE_PT_1_Y 180
       #define ABL_PROBE_PT_2_X 15
 
   #endif // AUTO_BED_LEVELING_GRID
 
-  // Offsets to the probe relative to the extruder tip (Hotend - Probe)
-  // X and Y offsets must be integers
-  #define X_PROBE_OFFSET_FROM_EXTRUDER -25     // Probe on: -left  +right
-  #define Y_PROBE_OFFSET_FROM_EXTRUDER -29     // Probe on: -front +behind
-  #define Z_PROBE_OFFSET_FROM_EXTRUDER -12.35  // -below (always!)
+  // Offsets to the Z probe relative to the nozzle tip.
+  // X and Y offsets must be integers.
+  #define X_PROBE_OFFSET_FROM_EXTRUDER -25     // Z probe to nozzle X offset: -left  +right
+  #define Y_PROBE_OFFSET_FROM_EXTRUDER -29     // Z probe to nozzle Y offset: -front +behind
+  #define Z_PROBE_OFFSET_FROM_EXTRUDER -12.35  // Z probe to nozzle Z offset: -below (always!)
 
-  #define Z_RAISE_BEFORE_HOMING 4       // (in mm) Raise Z before homing (G28) for Probe Clearance.
-                                        // Be sure you have this distance over your Z_MAX_POS in case
+  #define Z_RAISE_BEFORE_HOMING 4       // (in mm) Raise Z axis before homing (G28) for Z probe clearance.
+                                        // Be sure you have this distance over your Z_MAX_POS in case.
 
-  #define XY_TRAVEL_SPEED 8000         // X and Y axis travel speed between probes, in mm/min
+  #define XY_TRAVEL_SPEED 8000         // X and Y axis travel speed between probes, in mm/min.
 
-  #define Z_RAISE_BEFORE_PROBING 15   //How much the extruder will be raised before traveling to the first probing point.
-  #define Z_RAISE_BETWEEN_PROBINGS 5  //How much the extruder will be raised when traveling from between next probing points
-  #define Z_RAISE_AFTER_PROBING 15    //How much the extruder will be raised after the last probing point.
+  #define Z_RAISE_BEFORE_PROBING 15   // How much the Z axis will be raised before traveling to the first probing point.
+  #define Z_RAISE_BETWEEN_PROBINGS 5  // How much the Z axis will be raised when traveling from between next probing points.
+  #define Z_RAISE_AFTER_PROBING 15    // How much the Z axis will be raised after the last probing point.
 
-//   #define Z_PROBE_END_SCRIPT "G1 Z10 F12000\nG1 X15 Y330\nG1 Z0.5\nG1 Z10" //These commands will be executed in the end of G29 routine.
-                                                                            //Useful to retract a deployable probe.
+//   #define Z_PROBE_END_SCRIPT "G1 Z10 F12000\nG1 X15 Y330\nG1 Z0.5\nG1 Z10" // These commands will be executed in the end of G29 routine.
+                                                                            // Useful to retract a deployable Z probe.
                                                                            
-  //#define Z_PROBE_SLED // turn on if you have a z-probe mounted on a sled like those designed by Charles Bell
-  //#define SLED_DOCKING_OFFSET 5 // the extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
-
-  //If defined, the Probe servo will be turned on only during movement and then turned off to avoid jerk
-  //The value is the delay to turn the servo off after powered on - depends on the servo speed; 300ms is good value, but you can try lower it.
+  //#define Z_PROBE_SLED // Turn on if you have a Z probe mounted on a sled like those designed by Charles Bell.
+  //#define SLED_DOCKING_OFFSET 5 // The extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
 
+// If you have enabled the bed auto leveling and are using the same Z probe for Z homing,
+// it is highly recommended you let this Z_SAFE_HOMING enabled!!!
 
-//If you have enabled the Bed Auto Leveling and are using the same Z Probe for Z Homing,
-//it is highly recommended you let this Z_SAFE_HOMING enabled!!!
-
-  #define Z_SAFE_HOMING   // This feature is meant to avoid Z homing with probe outside the bed area.
+  #define Z_SAFE_HOMING   // This feature is meant to avoid Z homing with Z probe outside the bed area.
                           // When defined, it will:
-                          // - Allow Z homing only after X and Y homing AND stepper drivers still enabled
-                          // - If stepper drivers timeout, it will need X and Y homing again before Z homing
-                          // - Position the probe in a defined XY point before Z Homing when homing all axis (G28)
-                          // - Block Z homing only when the probe is outside bed area.
+                          // - Allow Z homing only after X and Y homing AND stepper drivers still enabled.
+                          // - If stepper drivers timeout, it will need X and Y homing again before Z homing.
+                          // - Position the Z probe in a defined XY point before Z Homing when homing all axis (G28).
+                          // - Block Z homing only when the Z probe is outside bed area.
 
   #if ENABLED(Z_SAFE_HOMING)
 
-    #define Z_SAFE_HOMING_X_POINT ((X_MIN_POS + X_MAX_POS) / 2)    // X point for Z homing when homing all axis (G28)
-    #define Z_SAFE_HOMING_Y_POINT ((Y_MIN_POS + Y_MAX_POS) / 2)    // Y point for Z homing when homing all axis (G28)
+    #define Z_SAFE_HOMING_X_POINT ((X_MIN_POS + X_MAX_POS) / 2)    // X point for Z homing when homing all axis (G28).
+    #define Z_SAFE_HOMING_Y_POINT ((Y_MIN_POS + Y_MAX_POS) / 2)    // Y point for Z homing when homing all axis (G28).
 
   #endif
 
-  // Support for a dedicated Z PROBE endstop separate from the Z MIN endstop.
-  // If you would like to use both a Z PROBE and a Z MIN endstop together , uncomment #define Z_MIN_PROBE_ENDSTOP and read the instructions below.
-  // If you want to still use the Z min endstop for homing, disable Z_SAFE_HOMING above. Eg; to park the head outside the bed area when homing with G28.
-  // WARNING: The Z MIN endstop will need to set properly as it would without a Z PROBE to prevent head crashes and premature stopping during a print.
-  // To use a separate Z PROBE endstop, you must have a Z_MIN_PROBE_PIN defined in the pins.h file for your control board.
-  // If you are using a servo based Z PROBE, you will need to enable NUM_SERVOS, Z_ENDSTOP_SERVO_NR and SERVO_ENDSTOP_ANGLES in the R/C Servo below.
-  // RAMPS 1.3/1.4 boards may be able to use the 5V, Ground and the D32 pin in the Aux 4 section of the RAMPS board. Use 5V for powered sensors, otherwise connect to ground and D32
-  // for normally closed configuration and 5V and D32 for normally open configurations. Normally closed configuration is advised and assumed.
-  // The D32 pin in Aux 4 on RAMPS maps to the Arduino D32 pin. Z_MIN_PROBE_PIN is setting the pin to use on the Arduino. Since the D32 pin on the RAMPS maps to D32 on Arduino, this works.
-  // D32 is currently selected in the RAMPS 1.3/1.4 pin file. All other boards will need changes to the respective pins_XXXXX.h file.
-  // WARNING: Setting the wrong pin may have unexpected and potentially disastrous outcomes. Use with caution and do your homework.
-
+  // Support for a dedicated Z probe endstop separate from the Z min endstop.
+  // If you would like to use both a Z probe and a Z min endstop together,
+  // uncomment #define Z_MIN_PROBE_ENDSTOP and read the instructions below.
+  // If you still want to use the Z min endstop for homing, disable Z_SAFE_HOMING above.
+  // Example: To park the head outside the bed area when homing with G28.
+  //
+  // WARNING:
+  // The Z min endstop will need to set properly as it would without a Z probe
+  // to prevent head crashes and premature stopping during a print.
+  //
+  // To use a separate Z probe endstop, you must have a Z_MIN_PROBE_PIN
+  // defined in the pins_XXXXX.h file for your control board.
+  // If you are using a servo based Z probe, you will need to enable NUM_SERVOS,
+  // Z_ENDSTOP_SERVO_NR and SERVO_ENDSTOP_ANGLES in the R/C SERVO support below.
+  // RAMPS 1.3/1.4 boards may be able to use the 5V, Ground and the D32 pin
+  // in the Aux 4 section of the RAMPS board. Use 5V for powered sensors,
+  // otherwise connect to ground and D32 for normally closed configuration
+  // and 5V and D32 for normally open configurations.
+  // Normally closed configuration is advised and assumed.
+  // The D32 pin in Aux 4 on RAMPS maps to the Arduino D32 pin.
+  // Z_MIN_PROBE_PIN is setting the pin to use on the Arduino.
+  // Since the D32 pin on the RAMPS maps to D32 on Arduino, this works.
+  // D32 is currently selected in the RAMPS 1.3/1.4 pin file.
+  // All other boards will need changes to the respective pins_XXXXX.h file.
+  //
+  // WARNING:
+  // Setting the wrong pin may have unexpected and potentially disastrous outcomes.
+  // Use with caution and do your homework.
+  //
   //#define Z_MIN_PROBE_ENDSTOP
 
 #endif // ENABLE_AUTO_BED_LEVELING
   #define EEPROM_CHITCHAT // please keep turned on if you can.
 #endif
 
+//
+// M100 Free Memory Watcher
+//
+//#define M100_FREE_MEMORY_WATCHER // uncomment to add the M100 Free Memory Watcher for debug purpose
+
+// @section temperature
+
 // Preheat Constants
 #define PLA_PREHEAT_HOTEND_TEMP 180
 #define PLA_PREHEAT_HPB_TEMP 70
 // Servo Endstops
 //
 // This allows for servo actuated endstops, primary usage is for the Z Axis to eliminate calibration or bed height changes.
-// Use M851 to set the z-probe vertical offset from the nozzle. Store that setting with M500.
+// Use M851 to set the Z probe vertical offset from the nozzle. Store that setting with M500.
 //
 //#define X_ENDSTOP_SERVO_NR 1
 //#define Y_ENDSTOP_SERVO_NR 2

Marlin/example_configurations/Hephestos/Configuration.h

 //#define DISABLE_MAX_ENDSTOPS
 //#define DISABLE_MIN_ENDSTOPS
 
-// If you want to enable the Z Probe pin, but disable its use, uncomment the line below.
-// This only affects a Z Probe Endstop if you have separate Z min endstop as well and have
-// activated Z_MIN_PROBE_ENDSTOP below. If you are using the Z Min endstop on your Z Probe,
+// If you want to enable the Z probe pin, but disable its use, uncomment the line below.
+// This only affects a Z probe endstop if you have separate Z min endstop as well and have
+// activated Z_MIN_PROBE_ENDSTOP below. If you are using the Z Min endstop on your Z probe,
 // this has no effect.
 //#define DISABLE_Z_MIN_PROBE_ENDSTOP
 
 //=========================== Manual Bed Leveling ===========================
 //===========================================================================
 
-// #define MANUAL_BED_LEVELING  // Add display menu option for bed leveling
-// #define MESH_BED_LEVELING    // Enable mesh bed leveling
+// #define MANUAL_BED_LEVELING  // Add display menu option for bed leveling.
+// #define MESH_BED_LEVELING    // Enable mesh bed leveling.
 
 #if ENABLED(MANUAL_BED_LEVELING)
-  #define MBL_Z_STEP 0.025  // Step size while manually probing Z axis
+  #define MBL_Z_STEP 0.025  // Step size while manually probing Z axis.
 #endif  // MANUAL_BED_LEVELING
 
 #if ENABLED(MESH_BED_LEVELING)
   #define MESH_MAX_X (X_MAX_POS - MESH_MIN_X)
   #define MESH_MIN_Y 10
   #define MESH_MAX_Y (Y_MAX_POS - MESH_MIN_Y)
-  #define MESH_NUM_X_POINTS 3  // Don't use more than 7 points per axis, implementation limited
+  #define MESH_NUM_X_POINTS 3  // Don't use more than 7 points per axis, implementation limited.
   #define MESH_NUM_Y_POINTS 3
-  #define MESH_HOME_SEARCH_Z 4  // Z after Home, bed somewhere below but above 0.0
+  #define MESH_HOME_SEARCH_Z 4  // Z after Home, bed somewhere below but above 0.0.
 #endif  // MESH_BED_LEVELING
 
 //===========================================================================
 
 // @section bedlevel
 
-//#define ENABLE_AUTO_BED_LEVELING // Delete the comment to enable (remove // at the start of the line)
-#define Z_MIN_PROBE_REPEATABILITY_TEST  // If not commented out, Z-Probe Repeatability test will be included if Auto Bed Leveling is Enabled.
+//#define ENABLE_AUTO_BED_LEVELING // Delete the comment to enable (remove // at the start of the line).
+#define Z_MIN_PROBE_REPEATABILITY_TEST  // If not commented out, Z probe repeatability test will be included if auto bed leveling is enabled.
 
 #if ENABLED(ENABLE_AUTO_BED_LEVELING)
 
-  // There are 2 different ways to specify probing locations
+  // There are 2 different ways to specify probing locations:
   //
   // - "grid" mode
   //   Probe several points in a rectangular grid.
   //   Probe 3 arbitrary points on the bed (that aren't colinear)
   //   You specify the XY coordinates of all 3 points.
 
-  // Enable this to sample the bed in a grid (least squares solution)
-  // Note: this feature generates 10KB extra code size
+  // Enable this to sample the bed in a grid (least squares solution).
+  // Note: this feature generates 10KB extra code size.
   #define AUTO_BED_LEVELING_GRID
 
   #if ENABLED(AUTO_BED_LEVELING_GRID)
     #define FRONT_PROBE_BED_POSITION 20
     #define BACK_PROBE_BED_POSITION 170
 
-    #define MIN_PROBE_EDGE 10 // The probe square sides can be no smaller than this
+    #define MIN_PROBE_EDGE 10 // The Z probe square sides can be no smaller than this.
 
-    // Set the number of grid points per dimension
-    // You probably don't need more than 3 (squared=9)
+    // Set the number of grid points per dimension.
+    // You probably don't need more than 3 (squared=9).
     #define AUTO_BED_LEVELING_GRID_POINTS 2
 
   #else  // !AUTO_BED_LEVELING_GRID
 
-      // Arbitrary points to probe. A simple cross-product
-      // is used to estimate the plane of the bed.
+      // Arbitrary points to probe.
+      // A simple cross-product is used to estimate the plane of the bed.
       #define ABL_PROBE_PT_1_X 15
       #define ABL_PROBE_PT_1_Y 180
       #define ABL_PROBE_PT_2_X 15
 
   #endif // AUTO_BED_LEVELING_GRID
 
-  // Offsets to the probe relative to the extruder tip (Hotend - Probe)
-  // X and Y offsets must be integers
-  #define X_PROBE_OFFSET_FROM_EXTRUDER -25     // Probe on: -left  +right
-  #define Y_PROBE_OFFSET_FROM_EXTRUDER -29     // Probe on: -front +behind
-  #define Z_PROBE_OFFSET_FROM_EXTRUDER -12.35  // -below (always!)
+  // Offsets to the Z probe relative to the nozzle tip.
+  // X and Y offsets must be integers.
+  #define X_PROBE_OFFSET_FROM_EXTRUDER -25     // Z probe to nozzle X offset: -left  +right
+  #define Y_PROBE_OFFSET_FROM_EXTRUDER -29     // Z probe to nozzle Y offset: -front +behind
+  #define Z_PROBE_OFFSET_FROM_EXTRUDER -12.35  // Z probe to nozzle Z offset: -below (always!)
 
-  #define Z_RAISE_BEFORE_HOMING 4       // (in mm) Raise Z before homing (G28) for Probe Clearance.
-                                        // Be sure you have this distance over your Z_MAX_POS in case
+  #define Z_RAISE_BEFORE_HOMING 4       // (in mm) Raise Z axis before homing (G28) for Z probe clearance.
+                                        // Be sure you have this distance over your Z_MAX_POS in case.
 
-  #define XY_TRAVEL_SPEED 8000         // X and Y axis travel speed between probes, in mm/min
+  #define XY_TRAVEL_SPEED 8000         // X and Y axis travel speed between probes, in mm/min.
 
-  #define Z_RAISE_BEFORE_PROBING 15   //How much the extruder will be raised before traveling to the first probing point.
-  #define Z_RAISE_BETWEEN_PROBINGS 5  //How much the extruder will be raised when traveling from between next probing points
-  #define Z_RAISE_AFTER_PROBING 15    //How much the extruder will be raised after the last probing point.
+  #define Z_RAISE_BEFORE_PROBING 15   // How much the Z axis will be raised before traveling to the first probing point.
+  #define Z_RAISE_BETWEEN_PROBINGS 5  // How much the Z axis will be raised when traveling from between next probing points.
+  #define Z_RAISE_AFTER_PROBING 15    // How much the Z axis will be raised after the last probing point.
 
-//   #define Z_PROBE_END_SCRIPT "G1 Z10 F12000\nG1 X15 Y330\nG1 Z0.5\nG1 Z10" //These commands will be executed in the end of G29 routine.
-                                                                            //Useful to retract a deployable probe.
+//   #define Z_PROBE_END_SCRIPT "G1 Z10 F12000\nG1 X15 Y330\nG1 Z0.5\nG1 Z10" // These commands will be executed in the end of G29 routine.
+                                                                            // Useful to retract a deployable Z probe.
 
-  //#define Z_PROBE_SLED // turn on if you have a z-probe mounted on a sled like those designed by Charles Bell
-  //#define SLED_DOCKING_OFFSET 5 // the extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
+  //#define Z_PROBE_SLED // Turn on if you have a Z probe mounted on a sled like those designed by Charles Bell.
+  //#define SLED_DOCKING_OFFSET 5 // The extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
 
-//If you have enabled the Bed Auto Leveling and are using the same Z Probe for Z Homing,
-//it is highly recommended you let this Z_SAFE_HOMING enabled!!!
+// If you have enabled the bed auto leveling and are using the same Z probe for Z homing,
+// it is highly recommended you let this Z_SAFE_HOMING enabled!!!
 
-  #define Z_SAFE_HOMING   // This feature is meant to avoid Z homing with probe outside the bed area.
+  #define Z_SAFE_HOMING   // This feature is meant to avoid Z homing with Z probe outside the bed area.
                           // When defined, it will:
-                          // - Allow Z homing only after X and Y homing AND stepper drivers still enabled
-                          // - If stepper drivers timeout, it will need X and Y homing again before Z homing
-                          // - Position the probe in a defined XY point before Z Homing when homing all axis (G28)
-                          // - Block Z homing only when the probe is outside bed area.
+                          // - Allow Z homing only after X and Y homing AND stepper drivers still enabled.
+                          // - If stepper drivers timeout, it will need X and Y homing again before Z homing.
+                          // - Position the Z probe in a defined XY point before Z Homing when homing all axis (G28).
+                          // - Block Z homing only when the Z probe is outside bed area.
 
   #if ENABLED(Z_SAFE_HOMING)
 
-    #define Z_SAFE_HOMING_X_POINT ((X_MIN_POS + X_MAX_POS) / 2)    // X point for Z homing when homing all axis (G28)
-    #define Z_SAFE_HOMING_Y_POINT ((Y_MIN_POS + Y_MAX_POS) / 2)    // Y point for Z homing when homing all axis (G28)
+    #define Z_SAFE_HOMING_X_POINT ((X_MIN_POS + X_MAX_POS) / 2)    // X point for Z homing when homing all axis (G28).
+    #define Z_SAFE_HOMING_Y_POINT ((Y_MIN_POS + Y_MAX_POS) / 2)    // Y point for Z homing when homing all axis (G28).
 
   #endif
 
-  // Support for a dedicated Z PROBE endstop separate from the Z MIN endstop.
-  // If you would like to use both a Z PROBE and a Z MIN endstop together , uncomment #define Z_MIN_PROBE_ENDSTOP and read the instructions below.
-  // If you want to still use the Z min endstop for homing, disable Z_SAFE_HOMING above. Eg; to park the head outside the bed area when homing with G28.
-  // WARNING: The Z MIN endstop will need to set properly as it would without a Z PROBE to prevent head crashes and premature stopping during a print.
-  // To use a separate Z PROBE endstop, you must have a Z_MIN_PROBE_PIN defined in the pins.h file for your control board.
-  // If you are using a servo based Z PROBE, you will need to enable NUM_SERVOS, Z_ENDSTOP_SERVO_NR and SERVO_ENDSTOP_ANGLES in the R/C Servo below.
-  // RAMPS 1.3/1.4 boards may be able to use the 5V, Ground and the D32 pin in the Aux 4 section of the RAMPS board. Use 5V for powered sensors, otherwise connect to ground and D32
-  // for normally closed configuration and 5V and D32 for normally open configurations. Normally closed configuration is advised and assumed.
-  // The D32 pin in Aux 4 on RAMPS maps to the Arduino D32 pin. Z_MIN_PROBE_PIN is setting the pin to use on the Arduino. Since the D32 pin on the RAMPS maps to D32 on Arduino, this works.
-  // D32 is currently selected in the RAMPS 1.3/1.4 pin file. All other boards will need changes to the respective pins_XXXXX.h file.
-  // WARNING: Setting the wrong pin may have unexpected and potentially disastrous outcomes. Use with caution and do your homework.
-
+  // Support for a dedicated Z probe endstop separate from the Z min endstop.
+  // If you would like to use both a Z probe and a Z min endstop together,
+  // uncomment #define Z_MIN_PROBE_ENDSTOP and read the instructions below.
+  // If you still want to use the Z min endstop for homing, disable Z_SAFE_HOMING above.
+  // Example: To park the head outside the bed area when homing with G28.
+  //
+  // WARNING:
+  // The Z min endstop will need to set properly as it would without a Z probe
+  // to prevent head crashes and premature stopping during a print.
+  //
+  // To use a separate Z probe endstop, you must have a Z_MIN_PROBE_PIN
+  // defined in the pins_XXXXX.h file for your control board.
+  // If you are using a servo based Z probe, you will need to enable NUM_SERVOS,
+  // Z_ENDSTOP_SERVO_NR and SERVO_ENDSTOP_ANGLES in the R/C SERVO support below.
+  // RAMPS 1.3/1.4 boards may be able to use the 5V, Ground and the D32 pin
+  // in the Aux 4 section of the RAMPS board. Use 5V for powered sensors,
+  // otherwise connect to ground and D32 for normally closed configuration
+  // and 5V and D32 for normally open configurations.
+  // Normally closed configuration is advised and assumed.
+  // The D32 pin in Aux 4 on RAMPS maps to the Arduino D32 pin.
+  // Z_MIN_PROBE_PIN is setting the pin to use on the Arduino.
+  // Since the D32 pin on the RAMPS maps to D32 on Arduino, this works.
+  // D32 is currently selected in the RAMPS 1.3/1.4 pin file.
+  // All other boards will need changes to the respective pins_XXXXX.h file.
+  //
+  // WARNING:
+  // Setting the wrong pin may have unexpected and potentially disastrous outcomes.
+  // Use with caution and do your homework.
+  //
   //#define Z_MIN_PROBE_ENDSTOP
 
 #endif // ENABLE_AUTO_BED_LEVELING
   #define EEPROM_CHITCHAT // Please keep turned on if you can.
 #endif
 
+//
+// M100 Free Memory Watcher
+//
+//#define M100_FREE_MEMORY_WATCHER // uncomment to add the M100 Free Memory Watcher for debug purpose
+
 // @section temperature
 
 // Preheat Constants
 // Servo Endstops
 //
 // This allows for servo actuated endstops, primary usage is for the Z Axis to eliminate calibration or bed height changes.
-// Use M851 to set the z-probe vertical offset from the nozzle. Store that setting with M500.
+// Use M851 to set the Z probe vertical offset from the nozzle. Store that setting with M500.
 //
 //#define X_ENDSTOP_SERVO_NR 1
 //#define Y_ENDSTOP_SERVO_NR 2

Marlin/example_configurations/K8200/Configuration.h

 #define DISABLE_MAX_ENDSTOPS
 //#define DISABLE_MIN_ENDSTOPS
 
-// If you want to enable the Z Probe pin, but disable its use, uncomment the line below.
-// This only affects a Z Probe Endstop if you have separate Z min endstop as well and have
-// activated Z_MIN_PROBE_ENDSTOP below. If you are using the Z Min endstop on your Z Probe,
+// If you want to enable the Z probe pin, but disable its use, uncomment the line below.
+// This only affects a Z probe endstop if you have separate Z min endstop as well and have
+// activated Z_MIN_PROBE_ENDSTOP below. If you are using the Z Min endstop on your Z probe,
 // this has no effect.
 //#define DISABLE_Z_MIN_PROBE_ENDSTOP
 
 //=========================== Manual Bed Leveling ===========================
 //===========================================================================
 
-// #define MANUAL_BED_LEVELING  // Add display menu option for bed leveling
-// #define MESH_BED_LEVELING    // Enable mesh bed leveling
+// #define MANUAL_BED_LEVELING  // Add display menu option for bed leveling.
+// #define MESH_BED_LEVELING    // Enable mesh bed leveling.
 
 #if ENABLED(MANUAL_BED_LEVELING)
-  #define MBL_Z_STEP 0.025  // Step size while manually probing Z axis
+  #define MBL_Z_STEP 0.025  // Step size while manually probing Z axis.
 #endif  // MANUAL_BED_LEVELING
 
 #if ENABLED(MESH_BED_LEVELING)
   #define MESH_MAX_X (X_MAX_POS - MESH_MIN_X)
   #define MESH_MIN_Y 10
   #define MESH_MAX_Y (Y_MAX_POS - MESH_MIN_Y)
-  #define MESH_NUM_X_POINTS 3  // Don't use more than 7 points per axis, implementation limited
+  #define MESH_NUM_X_POINTS 3  // Don't use more than 7 points per axis, implementation limited.
   #define MESH_NUM_Y_POINTS 3
-  #define MESH_HOME_SEARCH_Z 4  // Z after Home, bed somewhere below but above 0.0
+  #define MESH_HOME_SEARCH_Z 4  // Z after Home, bed somewhere below but above 0.0.
 #endif  // MESH_BED_LEVELING
 
 //===========================================================================
 
 // @section bedlevel
 
-//#define ENABLE_AUTO_BED_LEVELING // Delete the comment to enable (remove // at the start of the line)
-#define Z_MIN_PROBE_REPEATABILITY_TEST  // If not commented out, Z-Probe Repeatability test will be included if Auto Bed Leveling is Enabled.
+//#define ENABLE_AUTO_BED_LEVELING // Delete the comment to enable (remove // at the start of the line).
+#define Z_MIN_PROBE_REPEATABILITY_TEST  // If not commented out, Z probe repeatability test will be included if auto bed leveling is enabled.
 
 #if ENABLED(ENABLE_AUTO_BED_LEVELING)
 
-  // There are 2 different ways to specify probing locations
+  // There are 2 different ways to specify probing locations:
   //
   // - "grid" mode
   //   Probe several points in a rectangular grid.
   //   Probe 3 arbitrary points on the bed (that aren't colinear)
   //   You specify the XY coordinates of all 3 points.
 
-  // Enable this to sample the bed in a grid (least squares solution)
-  // Note: this feature generates 10KB extra code size
+  // Enable this to sample the bed in a grid (least squares solution).
+  // Note: this feature generates 10KB extra code size.
   #define AUTO_BED_LEVELING_GRID
 
   #if ENABLED(AUTO_BED_LEVELING_GRID)
     #define FRONT_PROBE_BED_POSITION 20
     #define BACK_PROBE_BED_POSITION 170
 
-    #define MIN_PROBE_EDGE 10 // The probe square sides can be no smaller than this
+    #define MIN_PROBE_EDGE 10 // The Z probe square sides can be no smaller than this.
 
-    // Set the number of grid points per dimension
-    // You probably don't need more than 3 (squared=9)
+    // Set the number of grid points per dimension.
+    // You probably don't need more than 3 (squared=9).
     #define AUTO_BED_LEVELING_GRID_POINTS 2
 
   #else  // !AUTO_BED_LEVELING_GRID
 
-      // Arbitrary points to probe. A simple cross-product
-      // is used to estimate the plane of the bed.
+      // Arbitrary points to probe.
+      // A simple cross-product is used to estimate the plane of the bed.
       #define ABL_PROBE_PT_1_X 15
       #define ABL_PROBE_PT_1_Y 180
       #define ABL_PROBE_PT_2_X 15
 
   #endif // AUTO_BED_LEVELING_GRID
 
-  // Offsets to the probe relative to the extruder tip (Hotend - Probe)
-  // X and Y offsets must be integers
-  #define X_PROBE_OFFSET_FROM_EXTRUDER -25     // Probe on: -left  +right
-  #define Y_PROBE_OFFSET_FROM_EXTRUDER -29     // Probe on: -front +behind
-  #define Z_PROBE_OFFSET_FROM_EXTRUDER -12.35  // -below (always!)
+  // Offsets to the Z probe relative to the nozzle tip.
+  // X and Y offsets must be integers.
+  #define X_PROBE_OFFSET_FROM_EXTRUDER -25     // Z probe to nozzle X offset: -left  +right
+  #define Y_PROBE_OFFSET_FROM_EXTRUDER -29     // Z probe to nozzle Y offset: -front +behind
+  #define Z_PROBE_OFFSET_FROM_EXTRUDER -12.35  // Z probe to nozzle Z offset: -below (always!)
 
-  #define Z_RAISE_BEFORE_HOMING 4       // (in mm) Raise Z before homing (G28) for Probe Clearance.
-                                        // Be sure you have this distance over your Z_MAX_POS in case
+  #define Z_RAISE_BEFORE_HOMING 4       // (in mm) Raise Z axis before homing (G28) for Z probe clearance.
+                                        // Be sure you have this distance over your Z_MAX_POS in case.
 
-  #define XY_TRAVEL_SPEED 8000         // X and Y axis travel speed between probes, in mm/min
+  #define XY_TRAVEL_SPEED 8000         // X and Y axis travel speed between probes, in mm/min.
 
-  #define Z_RAISE_BEFORE_PROBING 15   //How much the extruder will be raised before traveling to the first probing point.
-  #define Z_RAISE_BETWEEN_PROBINGS 5  //How much the extruder will be raised when traveling from between next probing points
-  #define Z_RAISE_AFTER_PROBING 15    //How much the extruder will be raised after the last probing point.
+  #define Z_RAISE_BEFORE_PROBING 15   // How much the Z axis will be raised before traveling to the first probing point.
+  #define Z_RAISE_BETWEEN_PROBINGS 5  // How much the Z axis will be raised when traveling from between next probing points.
+  #define Z_RAISE_AFTER_PROBING 15    // How much the Z axis will be raised after the last probing point.
 
-//   #define Z_PROBE_END_SCRIPT "G1 Z10 F12000\nG1 X15 Y330\nG1 Z0.5\nG1 Z10" //These commands will be executed in the end of G29 routine.
-                                                                            //Useful to retract a deployable probe.
+//   #define Z_PROBE_END_SCRIPT "G1 Z10 F12000\nG1 X15 Y330\nG1 Z0.5\nG1 Z10" // These commands will be executed in the end of G29 routine.
+                                                                            // Useful to retract a deployable Z probe.
 
-  //#define Z_PROBE_SLED // turn on if you have a z-probe mounted on a sled like those designed by Charles Bell
-  //#define SLED_DOCKING_OFFSET 5 // the extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
+  //#define Z_PROBE_SLED // Turn on if you have a Z probe mounted on a sled like those designed by Charles Bell.
+  //#define SLED_DOCKING_OFFSET 5 // The extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
 
-//If you have enabled the Bed Auto Leveling and are using the same Z Probe for Z Homing,
-//it is highly recommended you let this Z_SAFE_HOMING enabled!!!
+// If you have enabled the bed auto leveling and are using the same Z probe for Z homing,
+// it is highly recommended you let this Z_SAFE_HOMING enabled!!!
 
-  #define Z_SAFE_HOMING   // This feature is meant to avoid Z homing with probe outside the bed area.
+  #define Z_SAFE_HOMING   // This feature is meant to avoid Z homing with Z probe outside the bed area.
                           // When defined, it will:
-                          // - Allow Z homing only after X and Y homing AND stepper drivers still enabled
-                          // - If stepper drivers timeout, it will need X and Y homing again before Z homing
-                          // - Position the probe in a defined XY point before Z Homing when homing all axis (G28)
-                          // - Block Z homing only when the probe is outside bed area.
+                          // - Allow Z homing only after X and Y homing AND stepper drivers still enabled.
+                          // - If stepper drivers timeout, it will need X and Y homing again before Z homing.
+                          // - Position the Z probe in a defined XY point before Z Homing when homing all axis (G28).
+                          // - Block Z homing only when the Z probe is outside bed area.
 
   #if ENABLED(Z_SAFE_HOMING)
 
-    #define Z_SAFE_HOMING_X_POINT ((X_MIN_POS + X_MAX_POS) / 2)    // X point for Z homing when homing all axis (G28)
-    #define Z_SAFE_HOMING_Y_POINT ((Y_MIN_POS + Y_MAX_POS) / 2)    // Y point for Z homing when homing all axis (G28)
+    #define Z_SAFE_HOMING_X_POINT ((X_MIN_POS + X_MAX_POS) / 2)    // X point for Z homing when homing all axis (G28).
+    #define Z_SAFE_HOMING_Y_POINT ((Y_MIN_POS + Y_MAX_POS) / 2)    // Y point for Z homing when homing all axis (G28).
 
   #endif
 
-  // Support for a dedicated Z PROBE endstop separate from the Z MIN endstop.
-  // If you would like to use both a Z PROBE and a Z MIN endstop together , uncomment #define Z_MIN_PROBE_ENDSTOP and read the instructions below.
-  // If you want to still use the Z min endstop for homing, disable Z_SAFE_HOMING above. Eg; to park the head outside the bed area when homing with G28.
-  // WARNING: The Z MIN endstop will need to set properly as it would without a Z PROBE to prevent head crashes and premature stopping during a print.
-  // To use a separate Z PROBE endstop, you must have a Z_MIN_PROBE_PIN defined in the pins.h file for your control board.
-  // If you are using a servo based Z PROBE, you will need to enable NUM_SERVOS, Z_ENDSTOP_SERVO_NR and SERVO_ENDSTOP_ANGLES in the R/C Servo below.
-  // RAMPS 1.3/1.4 boards may be able to use the 5V, Ground and the D32 pin in the Aux 4 section of the RAMPS board. Use 5V for powered sensors, otherwise connect to ground and D32
-  // for normally closed configuration and 5V and D32 for normally open configurations. Normally closed configuration is advised and assumed.
-  // The D32 pin in Aux 4 on RAMPS maps to the Arduino D32 pin. Z_MIN_PROBE_PIN is setting the pin to use on the Arduino. Since the D32 pin on the RAMPS maps to D32 on Arduino, this works.
-  // D32 is currently selected in the RAMPS 1.3/1.4 pin file. All other boards will need changes to the respective pins_XXXXX.h file.
-  // WARNING: Setting the wrong pin may have unexpected and potentially disastrous outcomes. Use with caution and do your homework.
-
+  // Support for a dedicated Z probe endstop separate from the Z min endstop.
+  // If you would like to use both a Z probe and a Z min endstop together,
+  // uncomment #define Z_MIN_PROBE_ENDSTOP and read the instructions below.
+  // If you still want to use the Z min endstop for homing, disable Z_SAFE_HOMING above.
+  // Example: To park the head outside the bed area when homing with G28.
+  //
+  // WARNING:
+  // The Z min endstop will need to set properly as it would without a Z probe
+  // to prevent head crashes and premature stopping during a print.
+  //
+  // To use a separate Z probe endstop, you must have a Z_MIN_PROBE_PIN
+  // defined in the pins_XXXXX.h file for your control board.
+  // If you are using a servo based Z probe, you will need to enable NUM_SERVOS,
+  // Z_ENDSTOP_SERVO_NR and SERVO_ENDSTOP_ANGLES in the R/C SERVO support below.
+  // RAMPS 1.3/1.4 boards may be able to use the 5V, Ground and the D32 pin
+  // in the Aux 4 section of the RAMPS board. Use 5V for powered sensors,
+  // otherwise connect to ground and D32 for normally closed configuration
+  // and 5V and D32 for normally open configurations.
+  // Normally closed configuration is advised and assumed.
+  // The D32 pin in Aux 4 on RAMPS maps to the Arduino D32 pin.
+  // Z_MIN_PROBE_PIN is setting the pin to use on the Arduino.
+  // Since the D32 pin on the RAMPS maps to D32 on Arduino, this works.
+  // D32 is currently selected in the RAMPS 1.3/1.4 pin file.
+  // All other boards will need changes to the respective pins_XXXXX.h file.
+  //
+  // WARNING:
+  // Setting the wrong pin may have unexpected and potentially disastrous outcomes.
+  // Use with caution and do your homework.
+  //
   //#define Z_MIN_PROBE_ENDSTOP
 
 #endif // ENABLE_AUTO_BED_LEVELING
   #define EEPROM_CHITCHAT // Please keep turned on if you can.
 #endif
 
+//
+// M100 Free Memory Watcher
+//
+//#define M100_FREE_MEMORY_WATCHER // uncomment to add the M100 Free Memory Watcher for debug purpose
+
 // @section temperature
 
 // Preheat Constants
 // Servo Endstops
 //
 // This allows for servo actuated endstops, primary usage is for the Z Axis to eliminate calibration or bed height changes.
-// Use M851 to set the z-probe vertical offset from the nozzle. Store that setting with M500.
+// Use M851 to set the Z probe vertical offset from the nozzle. Store that setting with M500.
 //
 //#define X_ENDSTOP_SERVO_NR 1
 //#define Y_ENDSTOP_SERVO_NR 2

Marlin/example_configurations/RepRapWorld/Megatronics/Configuration.h

 //#define DISABLE_MAX_ENDSTOPS
 //#define DISABLE_MIN_ENDSTOPS
 
-// If you want to enable the Z Probe pin, but disable its use, uncomment the line below.
-// This only affects a Z Probe Endstop if you have separate Z min endstop as well and have
-// activated Z_MIN_PROBE_ENDSTOP below. If you are using the Z Min endstop on your Z Probe,
+// If you want to enable the Z probe pin, but disable its use, uncomment the line below.
+// This only affects a Z probe endstop if you have separate Z min endstop as well and have
+// activated Z_MIN_PROBE_ENDSTOP below. If you are using the Z Min endstop on your Z probe,
 // this has no effect.
 //#define DISABLE_Z_MIN_PROBE_ENDSTOP
 
 //=========================== Manual Bed Leveling ===========================
 //===========================================================================
 
-// #define MANUAL_BED_LEVELING  // Add display menu option for bed leveling
-// #define MESH_BED_LEVELING    // Enable mesh bed leveling
+// #define MANUAL_BED_LEVELING  // Add display menu option for bed leveling.
+// #define MESH_BED_LEVELING    // Enable mesh bed leveling.
 
 #if ENABLED(MANUAL_BED_LEVELING)
-  #define MBL_Z_STEP 0.025  // Step size while manually probing Z axis
+  #define MBL_Z_STEP 0.025  // Step size while manually probing Z axis.
 #endif  // MANUAL_BED_LEVELING
 
 #if ENABLED(MESH_BED_LEVELING)
   #define MESH_MAX_X (X_MAX_POS - MESH_MIN_X)
   #define MESH_MIN_Y 10
   #define MESH_MAX_Y (Y_MAX_POS - MESH_MIN_Y)
-  #define MESH_NUM_X_POINTS 3  // Don't use more than 7 points per axis, implementation limited
+  #define MESH_NUM_X_POINTS 3  // Don't use more than 7 points per axis, implementation limited.
   #define MESH_NUM_Y_POINTS 3
-  #define MESH_HOME_SEARCH_Z 4  // Z after Home, bed somewhere below but above 0.0
+  #define MESH_HOME_SEARCH_Z 4  // Z after Home, bed somewhere below but above 0.0.
 #endif  // MESH_BED_LEVELING
 
 //===========================================================================
 
 // @section bedlevel
 
-//#define ENABLE_AUTO_BED_LEVELING // Delete the comment to enable (remove // at the start of the line)
-#define Z_MIN_PROBE_REPEATABILITY_TEST  // If not commented out, Z-Probe Repeatability test will be included if Auto Bed Leveling is Enabled.
+//#define ENABLE_AUTO_BED_LEVELING // Delete the comment to enable (remove // at the start of the line).
+#define Z_MIN_PROBE_REPEATABILITY_TEST  // If not commented out, Z probe repeatability test will be included if auto bed leveling is enabled.
 
 #if ENABLED(ENABLE_AUTO_BED_LEVELING)
 
-  // There are 2 different ways to specify probing locations
+  // There are 2 different ways to specify probing locations:
   //
   // - "grid" mode
   //   Probe several points in a rectangular grid.
   //   Probe 3 arbitrary points on the bed (that aren't colinear)
   //   You specify the XY coordinates of all 3 points.
 
-  // Enable this to sample the bed in a grid (least squares solution)
-  // Note: this feature generates 10KB extra code size
+  // Enable this to sample the bed in a grid (least squares solution).
+  // Note: this feature generates 10KB extra code size.
   #define AUTO_BED_LEVELING_GRID
 
   #if ENABLED(AUTO_BED_LEVELING_GRID)
     #define FRONT_PROBE_BED_POSITION 20
     #define BACK_PROBE_BED_POSITION 170
 
-    #define MIN_PROBE_EDGE 10 // The probe square sides can be no smaller than this
+    #define MIN_PROBE_EDGE 10 // The Z probe square sides can be no smaller than this.
 
-    // Set the number of grid points per dimension
-    // You probably don't need more than 3 (squared=9)
+    // Set the number of grid points per dimension.
+    // You probably don't need more than 3 (squared=9).
     #define AUTO_BED_LEVELING_GRID_POINTS 2
 
   #else  // !AUTO_BED_LEVELING_GRID
 
-      // Arbitrary points to probe. A simple cross-product
-      // is used to estimate the plane of the bed.
+      // Arbitrary points to probe.
+      // A simple cross-product is used to estimate the plane of the bed.
       #define ABL_PROBE_PT_1_X 15
       #define ABL_PROBE_PT_1_Y 180
       #define ABL_PROBE_PT_2_X 15
 
   #endif // AUTO_BED_LEVELING_GRID
 
-  // Offsets to the probe relative to the extruder tip (Hotend - Probe)
-  // X and Y offsets must be integers
-  #define X_PROBE_OFFSET_FROM_EXTRUDER -25     // Probe on: -left  +right
-  #define Y_PROBE_OFFSET_FROM_EXTRUDER -29     // Probe on: -front +behind
-  #define Z_PROBE_OFFSET_FROM_EXTRUDER -12.35  // -below (always!)
+  // Offsets to the Z probe relative to the nozzle tip.
+  // X and Y offsets must be integers.
+  #define X_PROBE_OFFSET_FROM_EXTRUDER -25     // Z probe to nozzle X offset: -left  +right
+  #define Y_PROBE_OFFSET_FROM_EXTRUDER -29     // Z probe to nozzle Y offset: -front +behind
+  #define Z_PROBE_OFFSET_FROM_EXTRUDER -12.35  // Z probe to nozzle Z offset: -below (always!)
 
-  #define Z_RAISE_BEFORE_HOMING 4       // (in mm) Raise Z before homing (G28) for Probe Clearance.
-                                        // Be sure you have this distance over your Z_MAX_POS in case
+  #define Z_RAISE_BEFORE_HOMING 4       // (in mm) Raise Z axis before homing (G28) for Z probe clearance.
+                                        // Be sure you have this distance over your Z_MAX_POS in case.
 
-  #define XY_TRAVEL_SPEED 8000         // X and Y axis travel speed between probes, in mm/min
+  #define XY_TRAVEL_SPEED 8000         // X and Y axis travel speed between probes, in mm/min.
 
-  #define Z_RAISE_BEFORE_PROBING 15   //How much the extruder will be raised before traveling to the first probing point.
-  #define Z_RAISE_BETWEEN_PROBINGS 5  //How much the extruder will be raised when traveling from between next probing points
-  #define Z_RAISE_AFTER_PROBING 15    //How much the extruder will be raised after the last probing point.
+  #define Z_RAISE_BEFORE_PROBING 15   // How much the Z axis will be raised before traveling to the first probing point.
+  #define Z_RAISE_BETWEEN_PROBINGS 5  // How much the Z axis will be raised when traveling from between next probing points.
+  #define Z_RAISE_AFTER_PROBING 15    // How much the Z axis will be raised after the last probing point.
 
-//   #define Z_PROBE_END_SCRIPT "G1 Z10 F12000\nG1 X15 Y330\nG1 Z0.5\nG1 Z10" //These commands will be executed in the end of G29 routine.
-                                                                            //Useful to retract a deployable probe.
+//   #define Z_PROBE_END_SCRIPT "G1 Z10 F12000\nG1 X15 Y330\nG1 Z0.5\nG1 Z10" // These commands will be executed in the end of G29 routine.
+                                                                            // Useful to retract a deployable Z probe.
 
-  //#define Z_PROBE_SLED // turn on if you have a z-probe mounted on a sled like those designed by Charles Bell
-  //#define SLED_DOCKING_OFFSET 5 // the extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
+  //#define Z_PROBE_SLED // Turn on if you have a Z probe mounted on a sled like those designed by Charles Bell.
+  //#define SLED_DOCKING_OFFSET 5 // The extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
 
-//If you have enabled the Bed Auto Leveling and are using the same Z Probe for Z Homing,
-//it is highly recommended you let this Z_SAFE_HOMING enabled!!!
+// If you have enabled the bed auto leveling and are using the same Z probe for Z homing,
+// it is highly recommended you let this Z_SAFE_HOMING enabled!!!
 
-  #define Z_SAFE_HOMING   // This feature is meant to avoid Z homing with probe outside the bed area.
+  #define Z_SAFE_HOMING   // This feature is meant to avoid Z homing with Z probe outside the bed area.
                           // When defined, it will:
-                          // - Allow Z homing only after X and Y homing AND stepper drivers still enabled
-                          // - If stepper drivers timeout, it will need X and Y homing again before Z homing
-                          // - Position the probe in a defined XY point before Z Homing when homing all axis (G28)
-                          // - Block Z homing only when the probe is outside bed area.
+                          // - Allow Z homing only after X and Y homing AND stepper drivers still enabled.
+                          // - If stepper drivers timeout, it will need X and Y homing again before Z homing.
+                          // - Position the Z probe in a defined XY point before Z Homing when homing all axis (G28).
+                          // - Block Z homing only when the Z probe is outside bed area.
 
   #if ENABLED(Z_SAFE_HOMING)
 
-    #define Z_SAFE_HOMING_X_POINT ((X_MIN_POS + X_MAX_POS) / 2)    // X point for Z homing when homing all axis (G28)
-    #define Z_SAFE_HOMING_Y_POINT ((Y_MIN_POS + Y_MAX_POS) / 2)    // Y point for Z homing when homing all axis (G28)
+    #define Z_SAFE_HOMING_X_POINT ((X_MIN_POS + X_MAX_POS) / 2)    // X point for Z homing when homing all axis (G28).
+    #define Z_SAFE_HOMING_Y_POINT ((Y_MIN_POS + Y_MAX_POS) / 2)    // Y point for Z homing when homing all axis (G28).
 
   #endif
 
-  // Support for a dedicated Z PROBE endstop separate from the Z MIN endstop.
-  // If you would like to use both a Z PROBE and a Z MIN endstop together , uncomment #define Z_MIN_PROBE_ENDSTOP and read the instructions below.
-  // If you want to still use the Z min endstop for homing, disable Z_SAFE_HOMING above. Eg; to park the head outside the bed area when homing with G28.
-  // WARNING: The Z MIN endstop will need to set properly as it would without a Z PROBE to prevent head crashes and premature stopping during a print.
-  // To use a separate Z PROBE endstop, you must have a Z_MIN_PROBE_PIN defined in the pins.h file for your control board.
-  // If you are using a servo based Z PROBE, you will need to enable NUM_SERVOS, Z_ENDSTOP_SERVO_NR and SERVO_ENDSTOP_ANGLES in the R/C Servo below.
-  // RAMPS 1.3/1.4 boards may be able to use the 5V, Ground and the D32 pin in the Aux 4 section of the RAMPS board. Use 5V for powered sensors, otherwise connect to ground and D32
-  // for normally closed configuration and 5V and D32 for normally open configurations. Normally closed configuration is advised and assumed.
-  // The D32 pin in Aux 4 on RAMPS maps to the Arduino D32 pin. Z_MIN_PROBE_PIN is setting the pin to use on the Arduino. Since the D32 pin on the RAMPS maps to D32 on Arduino, this works.
-  // D32 is currently selected in the RAMPS 1.3/1.4 pin file. All other boards will need changes to the respective pins_XXXXX.h file.
-  // WARNING: Setting the wrong pin may have unexpected and potentially disastrous outcomes. Use with caution and do your homework.
-
+  // Support for a dedicated Z probe endstop separate from the Z min endstop.
+  // If you would like to use both a Z probe and a Z min endstop together,
+  // uncomment #define Z_MIN_PROBE_ENDSTOP and read the instructions below.
+  // If you still want to use the Z min endstop for homing, disable Z_SAFE_HOMING above.
+  // Example: To park the head outside the bed area when homing with G28.
+  //
+  // WARNING:
+  // The Z min endstop will need to set properly as it would without a Z probe
+  // to prevent head crashes and premature stopping during a print.
+  //
+  // To use a separate Z probe endstop, you must have a Z_MIN_PROBE_PIN
+  // defined in the pins_XXXXX.h file for your control board.
+  // If you are using a servo based Z probe, you will need to enable NUM_SERVOS,
+  // Z_ENDSTOP_SERVO_NR and SERVO_ENDSTOP_ANGLES in the R/C SERVO support below.
+  // RAMPS 1.3/1.4 boards may be able to use the 5V, Ground and the D32 pin
+  // in the Aux 4 section of the RAMPS board. Use 5V for powered sensors,
+  // otherwise connect to ground and D32 for normally closed configuration
+  // and 5V and D32 for normally open configurations.
+  // Normally closed configuration is advised and assumed.
+  // The D32 pin in Aux 4 on RAMPS maps to the Arduino D32 pin.
+  // Z_MIN_PROBE_PIN is setting the pin to use on the Arduino.
+  // Since the D32 pin on the RAMPS maps to D32 on Arduino, this works.
+  // D32 is currently selected in the RAMPS 1.3/1.4 pin file.
+  // All other boards will need changes to the respective pins_XXXXX.h file.
+  //
+  // WARNING:
+  // Setting the wrong pin may have unexpected and potentially disastrous outcomes.
+  // Use with caution and do your homework.
+  //
   //#define Z_MIN_PROBE_ENDSTOP
 
 #endif // ENABLE_AUTO_BED_LEVELING
   #define EEPROM_CHITCHAT // Please keep turned on if you can.
 #endif
 
+//
+// M100 Free Memory Watcher
+//
+//#define M100_FREE_MEMORY_WATCHER // uncomment to add the M100 Free Memory Watcher for debug purpose
+
 // @section temperature
 
 // Preheat Constants
 // Servo Endstops
 //
 // This allows for servo actuated endstops, primary usage is for the Z Axis to eliminate calibration or bed height changes.
-// Use M851 to set the z-probe vertical offset from the nozzle. Store that setting with M500.
+// Use M851 to set the Z probe vertical offset from the nozzle. Store that setting with M500.
 //
 //#define X_ENDSTOP_SERVO_NR 1
 //#define Y_ENDSTOP_SERVO_NR 2

Marlin/example_configurations/RigidBot/Configuration.h

 //#define DISABLE_MAX_ENDSTOPS
 //#define DISABLE_MIN_ENDSTOPS
 
-// If you want to enable the Z Probe pin, but disable its use, uncomment the line below.
-// This only affects a Z Probe Endstop if you have separate Z min endstop as well and have
-// activated Z_MIN_PROBE_ENDSTOP below. If you are using the Z Min endstop on your Z Probe,
+// If you want to enable the Z probe pin, but disable its use, uncomment the line below.
+// This only affects a Z probe endstop if you have separate Z min endstop as well and have
+// activated Z_MIN_PROBE_ENDSTOP below. If you are using the Z Min endstop on your Z probe,
 // this has no effect.
 //#define DISABLE_Z_MIN_PROBE_ENDSTOP
 
 //=========================== Manual Bed Leveling ===========================
 //===========================================================================
 
-// #define MANUAL_BED_LEVELING  // Add display menu option for bed leveling
-// #define MESH_BED_LEVELING    // Enable mesh bed leveling
+// #define MANUAL_BED_LEVELING  // Add display menu option for bed leveling.
+// #define MESH_BED_LEVELING    // Enable mesh bed leveling.
 
 #if ENABLED(MANUAL_BED_LEVELING)
-  #define MBL_Z_STEP 0.025  // Step size while manually probing Z axis
+  #define MBL_Z_STEP 0.025  // Step size while manually probing Z axis.
 #endif  // MANUAL_BED_LEVELING
 
 #if ENABLED(MESH_BED_LEVELING)
   #define MESH_MAX_X (X_MAX_POS - MESH_MIN_X)
   #define MESH_MIN_Y 10
   #define MESH_MAX_Y (Y_MAX_POS - MESH_MIN_Y)
-  #define MESH_NUM_X_POINTS 3  // Don't use more than 7 points per axis, implementation limited
+  #define MESH_NUM_X_POINTS 3  // Don't use more than 7 points per axis, implementation limited.
   #define MESH_NUM_Y_POINTS 3
-  #define MESH_HOME_SEARCH_Z 4  // Z after Home, bed somewhere below but above 0.0
+  #define MESH_HOME_SEARCH_Z 4  // Z after Home, bed somewhere below but above 0.0.
 #endif  // MESH_BED_LEVELING
 
 //===========================================================================
 
 // @section bedlevel
 
-//#define ENABLE_AUTO_BED_LEVELING // Delete the comment to enable (remove // at the start of the line)
-//#define Z_MIN_PROBE_REPEATABILITY_TEST  // If not commented out, Z-Probe Repeatability test will be included if Auto Bed Leveling is Enabled.
+//#define ENABLE_AUTO_BED_LEVELING // Delete the comment to enable (remove // at the start of the line).
+//#define Z_MIN_PROBE_REPEATABILITY_TEST  // If not commented out, Z probe repeatability test will be included if auto bed leveling is enabled.
 
 #if ENABLED(ENABLE_AUTO_BED_LEVELING)
 
-  // There are 2 different ways to specify probing locations
+  // There are 2 different ways to specify probing locations:
   //
   // - "grid" mode
   //   Probe several points in a rectangular grid.
   //   Probe 3 arbitrary points on the bed (that aren't colinear)
   //   You specify the XY coordinates of all 3 points.
 
-  // Enable this to sample the bed in a grid (least squares solution)
-  // Note: this feature generates 10KB extra code size
+  // Enable this to sample the bed in a grid (least squares solution).
+  // Note: this feature generates 10KB extra code size.
   #define AUTO_BED_LEVELING_GRID
 
   #if ENABLED(AUTO_BED_LEVELING_GRID)
     #define FRONT_PROBE_BED_POSITION 20
     #define BACK_PROBE_BED_POSITION 170
 
-    #define MIN_PROBE_EDGE 10 // The probe square sides can be no smaller than this
+    #define MIN_PROBE_EDGE 10 // The Z probe square sides can be no smaller than this.
 
-    // Set the number of grid points per dimension
-    // You probably don't need more than 3 (squared=9)
+    // Set the number of grid points per dimension.
+    // You probably don't need more than 3 (squared=9).
     #define AUTO_BED_LEVELING_GRID_POINTS 2
 
   #else  // !AUTO_BED_LEVELING_GRID
 
-      // Arbitrary points to probe. A simple cross-product
-      // is used to estimate the plane of the bed.
+      // Arbitrary points to probe.
+      // A simple cross-product is used to estimate the plane of the bed.
       #define ABL_PROBE_PT_1_X 15
       #define ABL_PROBE_PT_1_Y 180
       #define ABL_PROBE_PT_2_X 15
 
   #endif // AUTO_BED_LEVELING_GRID
 
-  // Offsets to the probe relative to the extruder tip (Hotend - Probe)
-  // X and Y offsets must be integers
-  #define X_PROBE_OFFSET_FROM_EXTRUDER -25     // Probe on: -left  +right
-  #define Y_PROBE_OFFSET_FROM_EXTRUDER -29     // Probe on: -front +behind
-  #define Z_PROBE_OFFSET_FROM_EXTRUDER -12.35  // -below (always!)
+  // Offsets to the Z probe relative to the nozzle tip.
+  // X and Y offsets must be integers.
+  #define X_PROBE_OFFSET_FROM_EXTRUDER -25     // Z probe to nozzle X offset: -left  +right
+  #define Y_PROBE_OFFSET_FROM_EXTRUDER -29     // Z probe to nozzle Y offset: -front +behind
+  #define Z_PROBE_OFFSET_FROM_EXTRUDER -12.35  // Z probe to nozzle Z offset: -below (always!)
 
-  #define Z_RAISE_BEFORE_HOMING 4       // (in mm) Raise Z before homing (G28) for Probe Clearance.
-                                        // Be sure you have this distance over your Z_MAX_POS in case
+  #define Z_RAISE_BEFORE_HOMING 4       // (in mm) Raise Z axis before homing (G28) for Z probe clearance.
+                                        // Be sure you have this distance over your Z_MAX_POS in case.
 
-  #define XY_TRAVEL_SPEED 8000         // X and Y axis travel speed between probes, in mm/min
+  #define XY_TRAVEL_SPEED 8000         // X and Y axis travel speed between probes, in mm/min.
 
-  #define Z_RAISE_BEFORE_PROBING 15   //How much the extruder will be raised before traveling to the first probing point.
-  #define Z_RAISE_BETWEEN_PROBINGS 5  //How much the extruder will be raised when traveling from between next probing points
-  #define Z_RAISE_AFTER_PROBING 15    //How much the extruder will be raised after the last probing point.
+  #define Z_RAISE_BEFORE_PROBING 15   // How much the Z axis will be raised before traveling to the first probing point.
+  #define Z_RAISE_BETWEEN_PROBINGS 5  // How much the Z axis will be raised when traveling from between next probing points.
+  #define Z_RAISE_AFTER_PROBING 15    // How much the Z axis will be raised after the last probing point.
 
-//   #define Z_PROBE_END_SCRIPT "G1 Z10 F12000\nG1 X15 Y330\nG1 Z0.5\nG1 Z10" //These commands will be executed in the end of G29 routine.
-                                                                            //Useful to retract a deployable probe.
+//   #define Z_PROBE_END_SCRIPT "G1 Z10 F12000\nG1 X15 Y330\nG1 Z0.5\nG1 Z10" // These commands will be executed in the end of G29 routine.
+                                                                            // Useful to retract a deployable Z probe.
 
-  //#define Z_PROBE_SLED // turn on if you have a z-probe mounted on a sled like those designed by Charles Bell
-  //#define SLED_DOCKING_OFFSET 5 // the extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
+  //#define Z_PROBE_SLED // Turn on if you have a Z probe mounted on a sled like those designed by Charles Bell.
+  //#define SLED_DOCKING_OFFSET 5 // The extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
 
-//If you have enabled the Bed Auto Leveling and are using the same Z Probe for Z Homing,
-//it is highly recommended you let this Z_SAFE_HOMING enabled!!!
+// If you have enabled the bed auto leveling and are using the same Z probe for Z homing,
+// it is highly recommended you let this Z_SAFE_HOMING enabled!!!
 
-  #define Z_SAFE_HOMING   // This feature is meant to avoid Z homing with probe outside the bed area.
+  #define Z_SAFE_HOMING   // This feature is meant to avoid Z homing with Z probe outside the bed area.
                           // When defined, it will:
-                          // - Allow Z homing only after X and Y homing AND stepper drivers still enabled
-                          // - If stepper drivers timeout, it will need X and Y homing again before Z homing
-                          // - Position the probe in a defined XY point before Z Homing when homing all axis (G28)
-                          // - Block Z homing only when the probe is outside bed area.
+                          // - Allow Z homing only after X and Y homing AND stepper drivers still enabled.
+                          // - If stepper drivers timeout, it will need X and Y homing again before Z homing.
+                          // - Position the Z probe in a defined XY point before Z Homing when homing all axis (G28).
+                          // - Block Z homing only when the Z probe is outside bed area.
 
   #if ENABLED(Z_SAFE_HOMING)
 
-    #define Z_SAFE_HOMING_X_POINT ((X_MIN_POS + X_MAX_POS) / 2)    // X point for Z homing when homing all axis (G28)
-    #define Z_SAFE_HOMING_Y_POINT ((Y_MIN_POS + Y_MAX_POS) / 2)    // Y point for Z homing when homing all axis (G28)
+    #define Z_SAFE_HOMING_X_POINT ((X_MIN_POS + X_MAX_POS) / 2)    // X point for Z homing when homing all axis (G28).
+    #define Z_SAFE_HOMING_Y_POINT ((Y_MIN_POS + Y_MAX_POS) / 2)    // Y point for Z homing when homing all axis (G28).
 
   #endif
 
-  // Support for a dedicated Z PROBE endstop separate from the Z MIN endstop.
-  // If you would like to use both a Z PROBE and a Z MIN endstop together , uncomment #define Z_MIN_PROBE_ENDSTOP and read the instructions below.
-  // If you want to still use the Z min endstop for homing, disable Z_SAFE_HOMING above. Eg; to park the head outside the bed area when homing with G28.
-  // WARNING: The Z MIN endstop will need to set properly as it would without a Z PROBE to prevent head crashes and premature stopping during a print.
-  // To use a separate Z PROBE endstop, you must have a Z_MIN_PROBE_PIN defined in the pins.h file for your control board.
-  // If you are using a servo based Z PROBE, you will need to enable NUM_SERVOS, Z_ENDSTOP_SERVO_NR and SERVO_ENDSTOP_ANGLES in the R/C Servo below.
-  // RAMPS 1.3/1.4 boards may be able to use the 5V, Ground and the D32 pin in the Aux 4 section of the RAMPS board. Use 5V for powered sensors, otherwise connect to ground and D32
-  // for normally closed configuration and 5V and D32 for normally open configurations. Normally closed configuration is advised and assumed.
-  // The D32 pin in Aux 4 on RAMPS maps to the Arduino D32 pin. Z_MIN_PROBE_PIN is setting the pin to use on the Arduino. Since the D32 pin on the RAMPS maps to D32 on Arduino, this works.
-  // D32 is currently selected in the RAMPS 1.3/1.4 pin file. All other boards will need changes to the respective pins_XXXXX.h file.
-  // WARNING: Setting the wrong pin may have unexpected and potentially disastrous outcomes. Use with caution and do your homework.
-
+  // Support for a dedicated Z probe endstop separate from the Z min endstop.
+  // If you would like to use both a Z probe and a Z min endstop together,
+  // uncomment #define Z_MIN_PROBE_ENDSTOP and read the instructions below.
+  // If you still want to use the Z min endstop for homing, disable Z_SAFE_HOMING above.
+  // Example: To park the head outside the bed area when homing with G28.
+  //
+  // WARNING:
+  // The Z min endstop will need to set properly as it would without a Z probe
+  // to prevent head crashes and premature stopping during a print.
+  //
+  // To use a separate Z probe endstop, you must have a Z_MIN_PROBE_PIN
+  // defined in the pins_XXXXX.h file for your control board.
+  // If you are using a servo based Z probe, you will need to enable NUM_SERVOS,
+  // Z_ENDSTOP_SERVO_NR and SERVO_ENDSTOP_ANGLES in the R/C SERVO support below.
+  // RAMPS 1.3/1.4 boards may be able to use the 5V, Ground and the D32 pin
+  // in the Aux 4 section of the RAMPS board. Use 5V for powered sensors,
+  // otherwise connect to ground and D32 for normally closed configuration
+  // and 5V and D32 for normally open configurations.
+  // Normally closed configuration is advised and assumed.
+  // The D32 pin in Aux 4 on RAMPS maps to the Arduino D32 pin.
+  // Z_MIN_PROBE_PIN is setting the pin to use on the Arduino.
+  // Since the D32 pin on the RAMPS maps to D32 on Arduino, this works.
+  // D32 is currently selected in the RAMPS 1.3/1.4 pin file.
+  // All other boards will need changes to the respective pins_XXXXX.h file.
+  //
+  // WARNING:
+  // Setting the wrong pin may have unexpected and potentially disastrous outcomes.
+  // Use with caution and do your homework.
+  //
   //#define Z_MIN_PROBE_ENDSTOP
 
 #endif // ENABLE_AUTO_BED_LEVELING
 // Servo Endstops
 //
 // This allows for servo actuated endstops, primary usage is for the Z Axis to eliminate calibration or bed height changes.
-// Use M851 to set the z-probe vertical offset from the nozzle. Store that setting with M500.
+// Use M851 to set the Z probe vertical offset from the nozzle. Store that setting with M500.
 //
 //#define X_ENDSTOP_SERVO_NR 1
 //#define Y_ENDSTOP_SERVO_NR 2

Marlin/example_configurations/SCARA/Configuration.h

 //#define DISABLE_MAX_ENDSTOPS
 //#define DISABLE_MIN_ENDSTOPS
 
-// If you want to enable the Z Probe pin, but disable its use, uncomment the line below.
-// This only affects a Z Probe Endstop if you have separate Z min endstop as well and have
-// activated Z_MIN_PROBE_ENDSTOP below. If you are using the Z Min endstop on your Z Probe,
+// If you want to enable the Z probe pin, but disable its use, uncomment the line below.
+// This only affects a Z probe endstop if you have separate Z min endstop as well and have
+// activated Z_MIN_PROBE_ENDSTOP below. If you are using the Z Min endstop on your Z probe,
 // this has no effect.
 //#define DISABLE_Z_MIN_PROBE_ENDSTOP
 
 //=========================== Manual Bed Leveling ===========================
 //===========================================================================
 
-// #define MANUAL_BED_LEVELING  // Add display menu option for bed leveling
-// #define MESH_BED_LEVELING    // Enable mesh bed leveling
+// #define MANUAL_BED_LEVELING  // Add display menu option for bed leveling.
+// #define MESH_BED_LEVELING    // Enable mesh bed leveling.
 
 #if ENABLED(MANUAL_BED_LEVELING)
-  #define MBL_Z_STEP 0.025  // Step size while manually probing Z axis
+  #define MBL_Z_STEP 0.025  // Step size while manually probing Z axis.
 #endif  // MANUAL_BED_LEVELING
 
 #if ENABLED(MESH_BED_LEVELING)
   #define MESH_MAX_X (X_MAX_POS - MESH_MIN_X)
   #define MESH_MIN_Y 10
   #define MESH_MAX_Y (Y_MAX_POS - MESH_MIN_Y)
-  #define MESH_NUM_X_POINTS 3  // Don't use more than 7 points per axis, implementation limited
+  #define MESH_NUM_X_POINTS 3  // Don't use more than 7 points per axis, implementation limited.
   #define MESH_NUM_Y_POINTS 3
-  #define MESH_HOME_SEARCH_Z 4  // Z after Home, bed somewhere below but above 0.0
+  #define MESH_HOME_SEARCH_Z 4  // Z after Home, bed somewhere below but above 0.0.
 #endif  // MESH_BED_LEVELING
 
 //===========================================================================
 
 // @section bedlevel
 
-//#define ENABLE_AUTO_BED_LEVELING // Delete the comment to enable (remove // at the start of the line)
-#define Z_MIN_PROBE_REPEATABILITY_TEST  // If not commented out, Z-Probe Repeatability test will be included if Auto Bed Leveling is Enabled.
+//#define ENABLE_AUTO_BED_LEVELING // Delete the comment to enable (remove // at the start of the line).
+#define Z_MIN_PROBE_REPEATABILITY_TEST  // If not commented out, Z probe repeatability test will be included if auto bed leveling is enabled.
 
 #if ENABLED(ENABLE_AUTO_BED_LEVELING)
 
-  // There are 2 different ways to specify probing locations
+  // There are 2 different ways to specify probing locations:
   //
   // - "grid" mode
   //   Probe several points in a rectangular grid.
   //   Probe 3 arbitrary points on the bed (that aren't colinear)
   //   You specify the XY coordinates of all 3 points.
 
-  // Enable this to sample the bed in a grid (least squares solution)
-  // Note: this feature generates 10KB extra code size
+  // Enable this to sample the bed in a grid (least squares solution).
+  // Note: this feature generates 10KB extra code size.
   #define AUTO_BED_LEVELING_GRID
 
   #if ENABLED(AUTO_BED_LEVELING_GRID)
     #define FRONT_PROBE_BED_POSITION 20
     #define BACK_PROBE_BED_POSITION 170
 
-    #define MIN_PROBE_EDGE 10 // The probe square sides can be no smaller than this
+    #define MIN_PROBE_EDGE 10 // The Z probe square sides can be no smaller than this.
 
-    // Set the number of grid points per dimension
-    // You probably don't need more than 3 (squared=9)
+    // Set the number of grid points per dimension.
+    // You probably don't need more than 3 (squared=9).
     #define AUTO_BED_LEVELING_GRID_POINTS 2
 
   #else  // !AUTO_BED_LEVELING_GRID
 
-      // Arbitrary points to probe. A simple cross-product
-      // is used to estimate the plane of the bed.
+      // Arbitrary points to probe.
+      // A simple cross-product is used to estimate the plane of the bed.
       #define ABL_PROBE_PT_1_X 15
       #define ABL_PROBE_PT_1_Y 180
       #define ABL_PROBE_PT_2_X 15
 
   #endif // AUTO_BED_LEVELING_GRID
 
-  // Offsets to the probe relative to the extruder tip (Hotend - Probe)
-  // X and Y offsets must be integers
-  #define X_PROBE_OFFSET_FROM_EXTRUDER -25     // Probe on: -left  +right
-  #define Y_PROBE_OFFSET_FROM_EXTRUDER -29     // Probe on: -front +behind
-  #define Z_PROBE_OFFSET_FROM_EXTRUDER -12.35  // -below (always!)
+  // Offsets to the Z probe relative to the nozzle tip.
+  // X and Y offsets must be integers.
+  #define X_PROBE_OFFSET_FROM_EXTRUDER -25     // Z probe to nozzle X offset: -left  +right
+  #define Y_PROBE_OFFSET_FROM_EXTRUDER -29     // Z probe to nozzle Y offset: -front +behind
+  #define Z_PROBE_OFFSET_FROM_EXTRUDER -12.35  // Z probe to nozzle Z offset: -below (always!)
 
-  //#define Z_RAISE_BEFORE_HOMING 4       // (in mm) Raise Z before homing (G28) for Probe Clearance.
-                                        // Be sure you have this distance over your Z_MAX_POS in case
+  //#define Z_RAISE_BEFORE_HOMING 4       // (in mm) Raise Z axis before homing (G28) for Z probe clearance.
+                                        // Be sure you have this distance over your Z_MAX_POS in case.
 
-  #define XY_TRAVEL_SPEED 8000         // X and Y axis travel speed between probes, in mm/min
+  #define XY_TRAVEL_SPEED 8000         // X and Y axis travel speed between probes, in mm/min.
 
-  #define Z_RAISE_BEFORE_PROBING 15   //How much the extruder will be raised before traveling to the first probing point.
-  #define Z_RAISE_BETWEEN_PROBINGS 5  //How much the extruder will be raised when traveling from between next probing points
-  #define Z_RAISE_AFTER_PROBING 15    //How much the extruder will be raised after the last probing point.
+  #define Z_RAISE_BEFORE_PROBING 15   // How much the Z axis will be raised before traveling to the first probing point.
+  #define Z_RAISE_BETWEEN_PROBINGS 5  // How much the Z axis will be raised when traveling from between next probing points.
+  #define Z_RAISE_AFTER_PROBING 15    // How much the Z axis will be raised after the last probing point.
 
-//   #define Z_PROBE_END_SCRIPT "G1 Z10 F12000\nG1 X15 Y330\nG1 Z0.5\nG1 Z10" //These commands will be executed in the end of G29 routine.
-                                                                            //Useful to retract a deployable probe.
+//   #define Z_PROBE_END_SCRIPT "G1 Z10 F12000\nG1 X15 Y330\nG1 Z0.5\nG1 Z10" // These commands will be executed in the end of G29 routine.
+                                                                            // Useful to retract a deployable Z probe.
 
-  //#define Z_PROBE_SLED // turn on if you have a z-probe mounted on a sled like those designed by Charles Bell
-  //#define SLED_DOCKING_OFFSET 5 // the extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
+  //#define Z_PROBE_SLED // Turn on if you have a Z probe mounted on a sled like those designed by Charles Bell.
+  //#define SLED_DOCKING_OFFSET 5 // The extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
 
-//If you have enabled the Bed Auto Leveling and are using the same Z Probe for Z Homing,
-//it is highly recommended you let this Z_SAFE_HOMING enabled!!!
+// If you have enabled the bed auto leveling and are using the same Z probe for Z homing,
+// it is highly recommended you let this Z_SAFE_HOMING enabled!!!
 
- // #define Z_SAFE_HOMING   // This feature is meant to avoid Z homing with probe outside the bed area.
+ // #define Z_SAFE_HOMING   // This feature is meant to avoid Z homing with Z probe outside the bed area.
                           // When defined, it will:
-                          // - Allow Z homing only after X and Y homing AND stepper drivers still enabled
-                          // - If stepper drivers timeout, it will need X and Y homing again before Z homing
-                          // - Position the probe in a defined XY point before Z Homing when homing all axis (G28)
-                          // - Block Z homing only when the probe is outside bed area.
+                          // - Allow Z homing only after X and Y homing AND stepper drivers still enabled.
+                          // - If stepper drivers timeout, it will need X and Y homing again before Z homing.
+                          // - Position the Z probe in a defined XY point before Z Homing when homing all axis (G28).
+                          // - Block Z homing only when the Z probe is outside bed area.
 
   #if ENABLED(Z_SAFE_HOMING)
 
-    #define Z_SAFE_HOMING_X_POINT ((X_MIN_POS + X_MAX_POS) / 2)    // X point for Z homing when homing all axis (G28)
-    #define Z_SAFE_HOMING_Y_POINT ((Y_MIN_POS + Y_MAX_POS) / 2)    // Y point for Z homing when homing all axis (G28)
+    #define Z_SAFE_HOMING_X_POINT ((X_MIN_POS + X_MAX_POS) / 2)    // X point for Z homing when homing all axis (G28).
+    #define Z_SAFE_HOMING_Y_POINT ((Y_MIN_POS + Y_MAX_POS) / 2)    // Y point for Z homing when homing all axis (G28).
 
   #endif
 
-  // Support for a dedicated Z PROBE endstop separate from the Z MIN endstop.
-  // If you would like to use both a Z PROBE and a Z MIN endstop together , uncomment #define Z_MIN_PROBE_ENDSTOP and read the instructions below.
-  // If you want to still use the Z min endstop for homing, disable Z_SAFE_HOMING above. Eg; to park the head outside the bed area when homing with G28.
-  // WARNING: The Z MIN endstop will need to set properly as it would without a Z PROBE to prevent head crashes and premature stopping during a print.
-  // To use a separate Z PROBE endstop, you must have a Z_MIN_PROBE_PIN defined in the pins.h file for your control board.
-  // If you are using a servo based Z PROBE, you will need to enable NUM_SERVOS, Z_ENDSTOP_SERVO_NR and SERVO_ENDSTOP_ANGLES in the R/C Servo below.
-  // RAMPS 1.3/1.4 boards may be able to use the 5V, Ground and the D32 pin in the Aux 4 section of the RAMPS board. Use 5V for powered sensors, otherwise connect to ground and D32
-  // for normally closed configuration and 5V and D32 for normally open configurations. Normally closed configuration is advised and assumed.
-  // The D32 pin in Aux 4 on RAMPS maps to the Arduino D32 pin. Z_MIN_PROBE_PIN is setting the pin to use on the Arduino. Since the D32 pin on the RAMPS maps to D32 on Arduino, this works.
-  // D32 is currently selected in the RAMPS 1.3/1.4 pin file. All other boards will need changes to the respective pins_XXXXX.h file.
-  // WARNING: Setting the wrong pin may have unexpected and potentially disastrous outcomes. Use with caution and do your homework.
-
+  // Support for a dedicated Z probe endstop separate from the Z min endstop.
+  // If you would like to use both a Z probe and a Z min endstop together,
+  // uncomment #define Z_MIN_PROBE_ENDSTOP and read the instructions below.
+  // If you still want to use the Z min endstop for homing, disable Z_SAFE_HOMING above.
+  // Example: To park the head outside the bed area when homing with G28.
+  //
+  // WARNING:
+  // The Z min endstop will need to set properly as it would without a Z probe
+  // to prevent head crashes and premature stopping during a print.
+  //
+  // To use a separate Z probe endstop, you must have a Z_MIN_PROBE_PIN
+  // defined in the pins_XXXXX.h file for your control board.
+  // If you are using a servo based Z probe, you will need to enable NUM_SERVOS,
+  // Z_ENDSTOP_SERVO_NR and SERVO_ENDSTOP_ANGLES in the R/C SERVO support below.
+  // RAMPS 1.3/1.4 boards may be able to use the 5V, Ground and the D32 pin
+  // in the Aux 4 section of the RAMPS board. Use 5V for powered sensors,
+  // otherwise connect to ground and D32 for normally closed configuration
+  // and 5V and D32 for normally open configurations.
+  // Normally closed configuration is advised and assumed.
+  // The D32 pin in Aux 4 on RAMPS maps to the Arduino D32 pin.
+  // Z_MIN_PROBE_PIN is setting the pin to use on the Arduino.
+  // Since the D32 pin on the RAMPS maps to D32 on Arduino, this works.
+  // D32 is currently selected in the RAMPS 1.3/1.4 pin file.
+  // All other boards will need changes to the respective pins_XXXXX.h file.
+  //
+  // WARNING:
+  // Setting the wrong pin may have unexpected and potentially disastrous outcomes.
+  // Use with caution and do your homework.
+  //
   //#define Z_MIN_PROBE_ENDSTOP
 
 #endif // ENABLE_AUTO_BED_LEVELING
   #define EEPROM_CHITCHAT // Please keep turned on if you can.
 #endif
 
+//
+// M100 Free Memory Watcher
+//
+//#define M100_FREE_MEMORY_WATCHER // uncomment to add the M100 Free Memory Watcher for debug purpose
+
 // @section temperature
 
 // Preheat Constants
 // Servo Endstops
 //
 // This allows for servo actuated endstops, primary usage is for the Z Axis to eliminate calibration or bed height changes.
-// Use M851 to set the z-probe vertical offset from the nozzle. Store that setting with M500.
+// Use M851 to set the Z probe vertical offset from the nozzle. Store that setting with M500.
 //
 //#define X_ENDSTOP_SERVO_NR 1
 //#define Y_ENDSTOP_SERVO_NR 2

Marlin/example_configurations/WITBOX/Configuration.h

 //#define DISABLE_MAX_ENDSTOPS
 //#define DISABLE_MIN_ENDSTOPS
 
-// If you want to enable the Z Probe pin, but disable its use, uncomment the line below.
-// This only affects a Z Probe Endstop if you have separate Z min endstop as well and have
-// activated Z_MIN_PROBE_ENDSTOP below. If you are using the Z Min endstop on your Z Probe,
+// If you want to enable the Z probe pin, but disable its use, uncomment the line below.
+// This only affects a Z probe endstop if you have separate Z min endstop as well and have
+// activated Z_MIN_PROBE_ENDSTOP below. If you are using the Z Min endstop on your Z probe,
 // this has no effect.
 //#define DISABLE_Z_MIN_PROBE_ENDSTOP
 
 //=========================== Manual Bed Leveling ===========================
 //===========================================================================
 
-// #define MANUAL_BED_LEVELING  // Add display menu option for bed leveling
-// #define MESH_BED_LEVELING    // Enable mesh bed leveling
+// #define MANUAL_BED_LEVELING  // Add display menu option for bed leveling.
+// #define MESH_BED_LEVELING    // Enable mesh bed leveling.
 
 #if ENABLED(MANUAL_BED_LEVELING)
-  #define MBL_Z_STEP 0.025  // Step size while manually probing Z axis
+  #define MBL_Z_STEP 0.025  // Step size while manually probing Z axis.
 #endif  // MANUAL_BED_LEVELING
 
 #if ENABLED(MESH_BED_LEVELING)
   #define MESH_MAX_X (X_MAX_POS - MESH_MIN_X)
   #define MESH_MIN_Y 10
   #define MESH_MAX_Y (Y_MAX_POS - MESH_MIN_Y)
-  #define MESH_NUM_X_POINTS 3  // Don't use more than 7 points per axis, implementation limited
+  #define MESH_NUM_X_POINTS 3  // Don't use more than 7 points per axis, implementation limited.
   #define MESH_NUM_Y_POINTS 3
-  #define MESH_HOME_SEARCH_Z 4  // Z after Home, bed somewhere below but above 0.0
+  #define MESH_HOME_SEARCH_Z 4  // Z after Home, bed somewhere below but above 0.0.
 #endif  // MESH_BED_LEVELING
 
 //===========================================================================
 
 // @section bedlevel
 
-//#define ENABLE_AUTO_BED_LEVELING // Delete the comment to enable (remove // at the start of the line)
-#define Z_MIN_PROBE_REPEATABILITY_TEST  // If not commented out, Z-Probe Repeatability test will be included if Auto Bed Leveling is Enabled.
+//#define ENABLE_AUTO_BED_LEVELING // Delete the comment to enable (remove // at the start of the line).
+#define Z_MIN_PROBE_REPEATABILITY_TEST  // If not commented out, Z probe repeatability test will be included if auto bed leveling is enabled.
 
 #if ENABLED(ENABLE_AUTO_BED_LEVELING)
 
-  // There are 2 different ways to specify probing locations
+  // There are 2 different ways to specify probing locations:
   //
   // - "grid" mode
   //   Probe several points in a rectangular grid.
   //   Probe 3 arbitrary points on the bed (that aren't colinear)
   //   You specify the XY coordinates of all 3 points.
 
-  // Enable this to sample the bed in a grid (least squares solution)
-  // Note: this feature generates 10KB extra code size
+  // Enable this to sample the bed in a grid (least squares solution).
+  // Note: this feature generates 10KB extra code size.
   #define AUTO_BED_LEVELING_GRID
 
   #if ENABLED(AUTO_BED_LEVELING_GRID)
     #define FRONT_PROBE_BED_POSITION 20
     #define BACK_PROBE_BED_POSITION 170
 
-    #define MIN_PROBE_EDGE 10 // The probe square sides can be no smaller than this
+    #define MIN_PROBE_EDGE 10 // The Z probe square sides can be no smaller than this.
 
-    // Set the number of grid points per dimension
-    // You probably don't need more than 3 (squared=9)
+    // Set the number of grid points per dimension.
+    // You probably don't need more than 3 (squared=9).
     #define AUTO_BED_LEVELING_GRID_POINTS 2
 
   #else  // !AUTO_BED_LEVELING_GRID
 
-      // Arbitrary points to probe. A simple cross-product
-      // is used to estimate the plane of the bed.
+      // Arbitrary points to probe.
+      // A simple cross-product is used to estimate the plane of the bed.
       #define ABL_PROBE_PT_1_X 15
       #define ABL_PROBE_PT_1_Y 180
       #define ABL_PROBE_PT_2_X 15
 
   #endif // AUTO_BED_LEVELING_GRID
 
-  // Offsets to the probe relative to the extruder tip (Hotend - Probe)
-  // X and Y offsets must be integers
-  #define X_PROBE_OFFSET_FROM_EXTRUDER -25     // Probe on: -left  +right
-  #define Y_PROBE_OFFSET_FROM_EXTRUDER -29     // Probe on: -front +behind
-  #define Z_PROBE_OFFSET_FROM_EXTRUDER -12.35  // -below (always!)
+  // Offsets to the Z probe relative to the nozzle tip.
+  // X and Y offsets must be integers.
+  #define X_PROBE_OFFSET_FROM_EXTRUDER -25     // Z probe to nozzle X offset: -left  +right
+  #define Y_PROBE_OFFSET_FROM_EXTRUDER -29     // Z probe to nozzle Y offset: -front +behind
+  #define Z_PROBE_OFFSET_FROM_EXTRUDER -12.35  // Z probe to nozzle Z offset: -below (always!)
 
-  #define Z_RAISE_BEFORE_HOMING 4       // (in mm) Raise Z before homing (G28) for Probe Clearance.
-                                        // Be sure you have this distance over your Z_MAX_POS in case
+  #define Z_RAISE_BEFORE_HOMING 4       // (in mm) Raise Z axis before homing (G28) for Z probe clearance.
+                                        // Be sure you have this distance over your Z_MAX_POS in case.
 
-  #define XY_TRAVEL_SPEED 8000         // X and Y axis travel speed between probes, in mm/min
+  #define XY_TRAVEL_SPEED 8000         // X and Y axis travel speed between probes, in mm/min.
 
-  #define Z_RAISE_BEFORE_PROBING 15   //How much the extruder will be raised before traveling to the first probing point.
-  #define Z_RAISE_BETWEEN_PROBINGS 5  //How much the extruder will be raised when traveling from between next probing points
-  #define Z_RAISE_AFTER_PROBING 15    //How much the extruder will be raised after the last probing point.
+  #define Z_RAISE_BEFORE_PROBING 15   // How much the Z axis will be raised before traveling to the first probing point.
+  #define Z_RAISE_BETWEEN_PROBINGS 5  // How much the Z axis will be raised when traveling from between next probing points.
+  #define Z_RAISE_AFTER_PROBING 15    // How much the Z axis will be raised after the last probing point.
 
-//   #define Z_PROBE_END_SCRIPT "G1 Z10 F12000\nG1 X15 Y330\nG1 Z0.5\nG1 Z10" //These commands will be executed in the end of G29 routine.
-                                                                            //Useful to retract a deployable probe.
+//   #define Z_PROBE_END_SCRIPT "G1 Z10 F12000\nG1 X15 Y330\nG1 Z0.5\nG1 Z10" // These commands will be executed in the end of G29 routine.
+                                                                            // Useful to retract a deployable Z probe.
 
-  //#define Z_PROBE_SLED // turn on if you have a z-probe mounted on a sled like those designed by Charles Bell
-  //#define SLED_DOCKING_OFFSET 5 // the extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
+  //#define Z_PROBE_SLED // Turn on if you have a Z probe mounted on a sled like those designed by Charles Bell.
+  //#define SLED_DOCKING_OFFSET 5 // The extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
 
-//If you have enabled the Bed Auto Leveling and are using the same Z Probe for Z Homing,
-//it is highly recommended you let this Z_SAFE_HOMING enabled!!!
+// If you have enabled the bed auto leveling and are using the same Z probe for Z homing,
+// it is highly recommended you let this Z_SAFE_HOMING enabled!!!
 
-  #define Z_SAFE_HOMING   // This feature is meant to avoid Z homing with probe outside the bed area.
+  #define Z_SAFE_HOMING   // This feature is meant to avoid Z homing with Z probe outside the bed area.
                           // When defined, it will:
-                          // - Allow Z homing only after X and Y homing AND stepper drivers still enabled
-                          // - If stepper drivers timeout, it will need X and Y homing again before Z homing
-                          // - Position the probe in a defined XY point before Z Homing when homing all axis (G28)
-                          // - Block Z homing only when the probe is outside bed area.
+                          // - Allow Z homing only after X and Y homing AND stepper drivers still enabled.
+                          // - If stepper drivers timeout, it will need X and Y homing again before Z homing.
+                          // - Position the Z probe in a defined XY point before Z Homing when homing all axis (G28).
+                          // - Block Z homing only when the Z probe is outside bed area.
 
   #if ENABLED(Z_SAFE_HOMING)
 
-    #define Z_SAFE_HOMING_X_POINT ((X_MIN_POS + X_MAX_POS) / 2)    // X point for Z homing when homing all axis (G28)
-    #define Z_SAFE_HOMING_Y_POINT ((Y_MIN_POS + Y_MAX_POS) / 2)    // Y point for Z homing when homing all axis (G28)
+    #define Z_SAFE_HOMING_X_POINT ((X_MIN_POS + X_MAX_POS) / 2)    // X point for Z homing when homing all axis (G28).
+    #define Z_SAFE_HOMING_Y_POINT ((Y_MIN_POS + Y_MAX_POS) / 2)    // Y point for Z homing when homing all axis (G28).
 
   #endif
 
-  // Support for a dedicated Z PROBE endstop separate from the Z MIN endstop.
-  // If you would like to use both a Z PROBE and a Z MIN endstop together , uncomment #define Z_MIN_PROBE_ENDSTOP and read the instructions below.
-  // If you want to still use the Z min endstop for homing, disable Z_SAFE_HOMING above. Eg; to park the head outside the bed area when homing with G28.
-  // WARNING: The Z MIN endstop will need to set properly as it would without a Z PROBE to prevent head crashes and premature stopping during a print.
-  // To use a separate Z PROBE endstop, you must have a Z_MIN_PROBE_PIN defined in the pins.h file for your control board.
-  // If you are using a servo based Z PROBE, you will need to enable NUM_SERVOS, Z_ENDSTOP_SERVO_NR and SERVO_ENDSTOP_ANGLES in the R/C Servo below.
-  // RAMPS 1.3/1.4 boards may be able to use the 5V, Ground and the D32 pin in the Aux 4 section of the RAMPS board. Use 5V for powered sensors, otherwise connect to ground and D32
-  // for normally closed configuration and 5V and D32 for normally open configurations. Normally closed configuration is advised and assumed.
-  // The D32 pin in Aux 4 on RAMPS maps to the Arduino D32 pin. Z_MIN_PROBE_PIN is setting the pin to use on the Arduino. Since the D32 pin on the RAMPS maps to D32 on Arduino, this works.
-  // D32 is currently selected in the RAMPS 1.3/1.4 pin file. All other boards will need changes to the respective pins_XXXXX.h file.
-  // WARNING: Setting the wrong pin may have unexpected and potentially disastrous outcomes. Use with caution and do your homework.
-
+  // Support for a dedicated Z probe endstop separate from the Z min endstop.
+  // If you would like to use both a Z probe and a Z min endstop together,
+  // uncomment #define Z_MIN_PROBE_ENDSTOP and read the instructions below.
+  // If you still want to use the Z min endstop for homing, disable Z_SAFE_HOMING above.
+  // Example: To park the head outside the bed area when homing with G28.
+  //
+  // WARNING:
+  // The Z min endstop will need to set properly as it would without a Z probe
+  // to prevent head crashes and premature stopping during a print.
+  //
+  // To use a separate Z probe endstop, you must have a Z_MIN_PROBE_PIN
+  // defined in the pins_XXXXX.h file for your control board.
+  // If you are using a servo based Z probe, you will need to enable NUM_SERVOS,
+  // Z_ENDSTOP_SERVO_NR and SERVO_ENDSTOP_ANGLES in the R/C SERVO support below.
+  // RAMPS 1.3/1.4 boards may be able to use the 5V, Ground and the D32 pin
+  // in the Aux 4 section of the RAMPS board. Use 5V for powered sensors,
+  // otherwise connect to ground and D32 for normally closed configuration
+  // and 5V and D32 for normally open configurations.
+  // Normally closed configuration is advised and assumed.
+  // The D32 pin in Aux 4 on RAMPS maps to the Arduino D32 pin.
+  // Z_MIN_PROBE_PIN is setting the pin to use on the Arduino.
+  // Since the D32 pin on the RAMPS maps to D32 on Arduino, this works.
+  // D32 is currently selected in the RAMPS 1.3/1.4 pin file.
+  // All other boards will need changes to the respective pins_XXXXX.h file.
+  //
+  // WARNING:
+  // Setting the wrong pin may have unexpected and potentially disastrous outcomes.
+  // Use with caution and do your homework.
+  //
   //#define Z_MIN_PROBE_ENDSTOP
 
 #endif // ENABLE_AUTO_BED_LEVELING
   #define EEPROM_CHITCHAT // Please keep turned on if you can.
 #endif
 
+//
+// M100 Free Memory Watcher
+//
+//#define M100_FREE_MEMORY_WATCHER // uncomment to add the M100 Free Memory Watcher for debug purpose
+
 // @section temperature
 
 // Preheat Constants
 // Servo Endstops
 //
 // This allows for servo actuated endstops, primary usage is for the Z Axis to eliminate calibration or bed height changes.
-// Use M851 to set the z-probe vertical offset from the nozzle. Store that setting with M500.
+// Use M851 to set the Z probe vertical offset from the nozzle. Store that setting with M500.
 //
 //#define X_ENDSTOP_SERVO_NR 1
 //#define Y_ENDSTOP_SERVO_NR 2

Marlin/example_configurations/adafruit/ST7565/Configuration.h

 //#define DISABLE_MAX_ENDSTOPS
 //#define DISABLE_MIN_ENDSTOPS
 
-// If you want to enable the Z Probe pin, but disable its use, uncomment the line below.
-// This only affects a Z Probe Endstop if you have separate Z min endstop as well and have
-// activated Z_MIN_PROBE_ENDSTOP below. If you are using the Z Min endstop on your Z Probe,
+// If you want to enable the Z probe pin, but disable its use, uncomment the line below.
+// This only affects a Z probe endstop if you have separate Z min endstop as well and have
+// activated Z_MIN_PROBE_ENDSTOP below. If you are using the Z Min endstop on your Z probe,
 // this has no effect.
 //#define DISABLE_Z_MIN_PROBE_ENDSTOP
 
 //=========================== Manual Bed Leveling ===========================
 //===========================================================================
 
-// #define MANUAL_BED_LEVELING  // Add display menu option for bed leveling
-// #define MESH_BED_LEVELING    // Enable mesh bed leveling
+// #define MANUAL_BED_LEVELING  // Add display menu option for bed leveling.
+// #define MESH_BED_LEVELING    // Enable mesh bed leveling.
 
 #if ENABLED(MANUAL_BED_LEVELING)
-  #define MBL_Z_STEP 0.025  // Step size while manually probing Z axis
+  #define MBL_Z_STEP 0.025  // Step size while manually probing Z axis.
 #endif  // MANUAL_BED_LEVELING
 
 #if ENABLED(MESH_BED_LEVELING)
   #define MESH_MAX_X (X_MAX_POS - MESH_MIN_X)
   #define MESH_MIN_Y 10
   #define MESH_MAX_Y (Y_MAX_POS - MESH_MIN_Y)
-  #define MESH_NUM_X_POINTS 3  // Don't use more than 7 points per axis, implementation limited
+  #define MESH_NUM_X_POINTS 3  // Don't use more than 7 points per axis, implementation limited.
   #define MESH_NUM_Y_POINTS 3
-  #define MESH_HOME_SEARCH_Z 4  // Z after Home, bed somewhere below but above 0.0
+  #define MESH_HOME_SEARCH_Z 4  // Z after Home, bed somewhere below but above 0.0.
 #endif  // MESH_BED_LEVELING
 
 //===========================================================================
 
 // @section bedlevel
 
-//#define ENABLE_AUTO_BED_LEVELING // Delete the comment to enable (remove // at the start of the line)
-#define Z_MIN_PROBE_REPEATABILITY_TEST  // If not commented out, Z-Probe Repeatability test will be included if Auto Bed Leveling is Enabled.
+//#define ENABLE_AUTO_BED_LEVELING // Delete the comment to enable (remove // at the start of the line).
+#define Z_MIN_PROBE_REPEATABILITY_TEST  // If not commented out, Z probe repeatability test will be included if auto bed leveling is enabled.
 
 #if ENABLED(ENABLE_AUTO_BED_LEVELING)
 
-  // There are 2 different ways to specify probing locations
+  // There are 2 different ways to specify probing locations:
   //
   // - "grid" mode
   //   Probe several points in a rectangular grid.
   //   Probe 3 arbitrary points on the bed (that aren't colinear)
   //   You specify the XY coordinates of all 3 points.
 
-  // Enable this to sample the bed in a grid (least squares solution)
-  // Note: this feature generates 10KB extra code size
+  // Enable this to sample the bed in a grid (least squares solution).
+  // Note: this feature generates 10KB extra code size.
   #define AUTO_BED_LEVELING_GRID
 
   #if ENABLED(AUTO_BED_LEVELING_GRID)
     #define FRONT_PROBE_BED_POSITION 20
     #define BACK_PROBE_BED_POSITION 170
 
-    #define MIN_PROBE_EDGE 10 // The probe square sides can be no smaller than this
+    #define MIN_PROBE_EDGE 10 // The Z probe square sides can be no smaller than this.
 
-    // Set the number of grid points per dimension
-    // You probably don't need more than 3 (squared=9)
+    // Set the number of grid points per dimension.
+    // You probably don't need more than 3 (squared=9).
     #define AUTO_BED_LEVELING_GRID_POINTS 2
 
   #else  // !AUTO_BED_LEVELING_GRID
 
-      // Arbitrary points to probe. A simple cross-product
-      // is used to estimate the plane of the bed.
+      // Arbitrary points to probe.
+      // A simple cross-product is used to estimate the plane of the bed.
       #define ABL_PROBE_PT_1_X 15
       #define ABL_PROBE_PT_1_Y 180
       #define ABL_PROBE_PT_2_X 15
 
   #endif // AUTO_BED_LEVELING_GRID
 
-  // Offsets to the probe relative to the extruder tip (Hotend - Probe)
-  // X and Y offsets must be integers
-  #define X_PROBE_OFFSET_FROM_EXTRUDER -25     // Probe on: -left  +right
-  #define Y_PROBE_OFFSET_FROM_EXTRUDER -29     // Probe on: -front +behind
-  #define Z_PROBE_OFFSET_FROM_EXTRUDER -12.35  // -below (always!)
+  // Offsets to the Z probe relative to the nozzle tip.
+  // X and Y offsets must be integers.
+  #define X_PROBE_OFFSET_FROM_EXTRUDER -25     // Z probe to nozzle X offset: -left  +right
+  #define Y_PROBE_OFFSET_FROM_EXTRUDER -29     // Z probe to nozzle Y offset: -front +behind
+  #define Z_PROBE_OFFSET_FROM_EXTRUDER -12.35  // Z probe to nozzle Z offset: -below (always!)
 
-  #define Z_RAISE_BEFORE_HOMING 4       // (in mm) Raise Z before homing (G28) for Probe Clearance.
-                                        // Be sure you have this distance over your Z_MAX_POS in case
+  #define Z_RAISE_BEFORE_HOMING 4       // (in mm) Raise Z axis before homing (G28) for Z probe clearance.
+                                        // Be sure you have this distance over your Z_MAX_POS in case.
 
-  #define XY_TRAVEL_SPEED 8000         // X and Y axis travel speed between probes, in mm/min
+  #define XY_TRAVEL_SPEED 8000         // X and Y axis travel speed between probes, in mm/min.
 
-  #define Z_RAISE_BEFORE_PROBING 15   //How much the extruder will be raised before traveling to the first probing point.
-  #define Z_RAISE_BETWEEN_PROBINGS 5  //How much the extruder will be raised when traveling from between next probing points
-  #define Z_RAISE_AFTER_PROBING 15    //How much the extruder will be raised after the last probing point.
+  #define Z_RAISE_BEFORE_PROBING 15   // How much the Z axis will be raised before traveling to the first probing point.
+  #define Z_RAISE_BETWEEN_PROBINGS 5  // How much the Z axis will be raised when traveling from between next probing points.
+  #define Z_RAISE_AFTER_PROBING 15    // How much the Z axis will be raised after the last probing point.
 
-//   #define Z_PROBE_END_SCRIPT "G1 Z10 F12000\nG1 X15 Y330\nG1 Z0.5\nG1 Z10" //These commands will be executed in the end of G29 routine.
-                                                                            //Useful to retract a deployable probe.
+//   #define Z_PROBE_END_SCRIPT "G1 Z10 F12000\nG1 X15 Y330\nG1 Z0.5\nG1 Z10" // These commands will be executed in the end of G29 routine.
+                                                                            // Useful to retract a deployable Z probe.
 
-  //#define Z_PROBE_SLED // turn on if you have a z-probe mounted on a sled like those designed by Charles Bell
-  //#define SLED_DOCKING_OFFSET 5 // the extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
+  //#define Z_PROBE_SLED // Turn on if you have a Z probe mounted on a sled like those designed by Charles Bell.
+  //#define SLED_DOCKING_OFFSET 5 // The extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
 
-//If you have enabled the Bed Auto Leveling and are using the same Z Probe for Z Homing,
-//it is highly recommended you let this Z_SAFE_HOMING enabled!!!
+// If you have enabled the bed auto leveling and are using the same Z probe for Z homing,
+// it is highly recommended you let this Z_SAFE_HOMING enabled!!!
 
-  #define Z_SAFE_HOMING   // This feature is meant to avoid Z homing with probe outside the bed area.
+  #define Z_SAFE_HOMING   // This feature is meant to avoid Z homing with Z probe outside the bed area.
                           // When defined, it will:
-                          // - Allow Z homing only after X and Y homing AND stepper drivers still enabled
-                          // - If stepper drivers timeout, it will need X and Y homing again before Z homing
-                          // - Position the probe in a defined XY point before Z Homing when homing all axis (G28)
-                          // - Block Z homing only when the probe is outside bed area.
+                          // - Allow Z homing only after X and Y homing AND stepper drivers still enabled.
+                          // - If stepper drivers timeout, it will need X and Y homing again before Z homing.
+                          // - Position the Z probe in a defined XY point before Z Homing when homing all axis (G28).
+                          // - Block Z homing only when the Z probe is outside bed area.
 
   #if ENABLED(Z_SAFE_HOMING)
 
-    #define Z_SAFE_HOMING_X_POINT ((X_MIN_POS + X_MAX_POS) / 2)    // X point for Z homing when homing all axis (G28)
-    #define Z_SAFE_HOMING_Y_POINT ((Y_MIN_POS + Y_MAX_POS) / 2)    // Y point for Z homing when homing all axis (G28)
+    #define Z_SAFE_HOMING_X_POINT ((X_MIN_POS + X_MAX_POS) / 2)    // X point for Z homing when homing all axis (G28).
+    #define Z_SAFE_HOMING_Y_POINT ((Y_MIN_POS + Y_MAX_POS) / 2)    // Y point for Z homing when homing all axis (G28).
 
   #endif
 
-  // Support for a dedicated Z PROBE endstop separate from the Z MIN endstop.
-  // If you would like to use both a Z PROBE and a Z MIN endstop together , uncomment #define Z_MIN_PROBE_ENDSTOP and read the instructions below.
-  // If you want to still use the Z min endstop for homing, disable Z_SAFE_HOMING above. Eg; to park the head outside the bed area when homing with G28.
-  // WARNING: The Z MIN endstop will need to set properly as it would without a Z PROBE to prevent head crashes and premature stopping during a print.
-  // To use a separate Z PROBE endstop, you must have a Z_MIN_PROBE_PIN defined in the pins.h file for your control board.
-  // If you are using a servo based Z PROBE, you will need to enable NUM_SERVOS, Z_ENDSTOP_SERVO_NR and SERVO_ENDSTOP_ANGLES in the R/C Servo below.
-  // RAMPS 1.3/1.4 boards may be able to use the 5V, Ground and the D32 pin in the Aux 4 section of the RAMPS board. Use 5V for powered sensors, otherwise connect to ground and D32
-  // for normally closed configuration and 5V and D32 for normally open configurations. Normally closed configuration is advised and assumed.
-  // The D32 pin in Aux 4 on RAMPS maps to the Arduino D32 pin. Z_MIN_PROBE_PIN is setting the pin to use on the Arduino. Since the D32 pin on the RAMPS maps to D32 on Arduino, this works.
-  // D32 is currently selected in the RAMPS 1.3/1.4 pin file. All other boards will need changes to the respective pins_XXXXX.h file.
-  // WARNING: Setting the wrong pin may have unexpected and potentially disastrous outcomes. Use with caution and do your homework.
-
+  // Support for a dedicated Z probe endstop separate from the Z min endstop.
+  // If you would like to use both a Z probe and a Z min endstop together,
+  // uncomment #define Z_MIN_PROBE_ENDSTOP and read the instructions below.
+  // If you still want to use the Z min endstop for homing, disable Z_SAFE_HOMING above.
+  // Example: To park the head outside the bed area when homing with G28.
+  //
+  // WARNING:
+  // The Z min endstop will need to set properly as it would without a Z probe
+  // to prevent head crashes and premature stopping during a print.
+  //
+  // To use a separate Z probe endstop, you must have a Z_MIN_PROBE_PIN
+  // defined in the pins_XXXXX.h file for your control board.
+  // If you are using a servo based Z probe, you will need to enable NUM_SERVOS,
+  // Z_ENDSTOP_SERVO_NR and SERVO_ENDSTOP_ANGLES in the R/C SERVO support below.
+  // RAMPS 1.3/1.4 boards may be able to use the 5V, Ground and the D32 pin
+  // in the Aux 4 section of the RAMPS board. Use 5V for powered sensors,
+  // otherwise connect to ground and D32 for normally closed configuration
+  // and 5V and D32 for normally open configurations.
+  // Normally closed configuration is advised and assumed.
+  // The D32 pin in Aux 4 on RAMPS maps to the Arduino D32 pin.
+  // Z_MIN_PROBE_PIN is setting the pin to use on the Arduino.
+  // Since the D32 pin on the RAMPS maps to D32 on Arduino, this works.
+  // D32 is currently selected in the RAMPS 1.3/1.4 pin file.
+  // All other boards will need changes to the respective pins_XXXXX.h file.
+  //
+  // WARNING:
+  // Setting the wrong pin may have unexpected and potentially disastrous outcomes.
+  // Use with caution and do your homework.
+  //
   //#define Z_MIN_PROBE_ENDSTOP
 
 #endif // ENABLE_AUTO_BED_LEVELING
   #define EEPROM_CHITCHAT // Please keep turned on if you can.
 #endif
 
+//
+// M100 Free Memory Watcher
+//
+//#define M100_FREE_MEMORY_WATCHER // uncomment to add the M100 Free Memory Watcher for debug purpose
+
 // @section temperature
 
 // Preheat Constants
 // Servo Endstops
 //
 // This allows for servo actuated endstops, primary usage is for the Z Axis to eliminate calibration or bed height changes.
-// Use M851 to set the z-probe vertical offset from the nozzle. Store that setting with M500.
+// Use M851 to set the Z probe vertical offset from the nozzle. Store that setting with M500.
 //
 //#define X_ENDSTOP_SERVO_NR 1
 //#define Y_ENDSTOP_SERVO_NR 2

Marlin/example_configurations/delta/biv2.5/Configuration.h

 const bool Z_MAX_ENDSTOP_INVERTING = false; // set to true to invert the logic of the endstop.
 const bool Z_MIN_PROBE_ENDSTOP_INVERTING = true; // set to true to invert the logic of the endstop.
 //#define DISABLE_MAX_ENDSTOPS
-#define DISABLE_MIN_ENDSTOPS // Deltas only use min endstops for probing
+#define DISABLE_MIN_ENDSTOPS // Deltas only use min endstops for probing.
 
-// If you want to enable the Z Probe pin, but disable its use, uncomment the line below.
-// This only affects a Z Probe Endstop if you have separate Z min endstop as well and have
-// activated Z_MIN_PROBE_ENDSTOP below. If you are using the Z Min endstop on your Z Probe,
+// If you want to enable the Z probe pin, but disable its use, uncomment the line below.
+// This only affects a Z probe endstop if you have separate Z min endstop as well and have
+// activated Z_MIN_PROBE_ENDSTOP below. If you are using the Z Min endstop on your Z probe,
 // this has no effect.
 //#define DISABLE_Z_MIN_PROBE_ENDSTOP
 
 //=========================== Manual Bed Leveling ===========================
 //===========================================================================
 
-// #define MANUAL_BED_LEVELING  // Add display menu option for bed leveling
-// #define MESH_BED_LEVELING    // Enable mesh bed leveling
+// #define MANUAL_BED_LEVELING  // Add display menu option for bed leveling.
+// #define MESH_BED_LEVELING    // Enable mesh bed leveling.
 
 #if ENABLED(MANUAL_BED_LEVELING)
-  #define MBL_Z_STEP 0.025  // Step size while manually probing Z axis
+  #define MBL_Z_STEP 0.025  // Step size while manually probing Z axis.
 #endif  // MANUAL_BED_LEVELING
 
 #if ENABLED(MESH_BED_LEVELING)
   #define MESH_MAX_X (X_MAX_POS - MESH_MIN_X)
   #define MESH_MIN_Y 10
   #define MESH_MAX_Y (Y_MAX_POS - MESH_MIN_Y)
-  #define MESH_NUM_X_POINTS 3  // Don't use more than 7 points per axis, implementation limited
+  #define MESH_NUM_X_POINTS 3  // Don't use more than 7 points per axis, implementation limited.
   #define MESH_NUM_Y_POINTS 3
-  #define MESH_HOME_SEARCH_Z 4  // Z after Home, bed somewhere below but above 0.0
+  #define MESH_HOME_SEARCH_Z 4  // Z after Home, bed somewhere below but above 0.0.
 #endif  // MESH_BED_LEVELING
 
 //===========================================================================
 
 // @section bedlevel
 
-//#define ENABLE_AUTO_BED_LEVELING // Delete the comment to enable (remove // at the start of the line)
-//#define Z_MIN_PROBE_REPEATABILITY_TEST // Z-Probe Repeatability test is not supported in Deltas yet.
+//#define ENABLE_AUTO_BED_LEVELING // Delete the comment to enable (remove // at the start of the line).
+//#define Z_MIN_PROBE_REPEATABILITY_TEST // Z probe repeatability test is not supported in Deltas yet.
 
 #if ENABLED(ENABLE_AUTO_BED_LEVELING)
 
-  // There are 2 different ways to specify probing locations
+  // There are 2 different ways to specify probing locations:
   //
   // - "grid" mode
   //   Probe several points in a rectangular grid.
   //   Probe 3 arbitrary points on the bed (that aren't colinear)
   //   You specify the XY coordinates of all 3 points.
 
-  // Enable this to sample the bed in a grid (least squares solution)
-  // Note: this feature generates 10KB extra code size
-  #define AUTO_BED_LEVELING_GRID  // Deltas only support grid mode
+  // Enable this to sample the bed in a grid (least squares solution).
+  // Note: this feature generates 10KB extra code size.
+  #define AUTO_BED_LEVELING_GRID  // Deltas only support grid mode.
 
   #if ENABLED(AUTO_BED_LEVELING_GRID)
 
-    // set the rectangle in which to probe
+    // Set the rectangle in which to probe.
     #define DELTA_PROBABLE_RADIUS (DELTA_PRINTABLE_RADIUS - 10)
     #define LEFT_PROBE_BED_POSITION -DELTA_PROBABLE_RADIUS
     #define RIGHT_PROBE_BED_POSITION DELTA_PROBABLE_RADIUS
     #define FRONT_PROBE_BED_POSITION -DELTA_PROBABLE_RADIUS
     #define BACK_PROBE_BED_POSITION DELTA_PROBABLE_RADIUS
 
-    #define MIN_PROBE_EDGE 10 // The probe square sides can be no smaller than this
+    #define MIN_PROBE_EDGE 10 // The Z probe square sides can be no smaller than this.
 
     // Non-linear bed leveling will be used.
     // Compensate by interpolating between the nearest four Z probe values for each point.
 
   #else  // !AUTO_BED_LEVELING_GRID
 
-      // Arbitrary points to probe. A simple cross-product
-      // is used to estimate the plane of the bed.
+      // Arbitrary points to probe.
+      // A simple cross-product is used to estimate the plane of the bed.
       #define ABL_PROBE_PT_1_X 15
       #define ABL_PROBE_PT_1_Y 180
       #define ABL_PROBE_PT_2_X 15
 
   #endif // AUTO_BED_LEVELING_GRID
 
-  // Offsets to the probe relative to the extruder tip (Hotend - Probe)
-  // X and Y offsets must be integers
-  #define X_PROBE_OFFSET_FROM_EXTRUDER 0     // Probe on: -left  +right
-  #define Y_PROBE_OFFSET_FROM_EXTRUDER -10   // Probe on: -front +behind
-  #define Z_PROBE_OFFSET_FROM_EXTRUDER -3.5  // -below (always!)
+  // Offsets to the Z probe relative to the nozzle tip.
+  // X and Y offsets must be integers.
+  #define X_PROBE_OFFSET_FROM_EXTRUDER 0     // Z probe to nozzle X offset: -left  +right
+  #define Y_PROBE_OFFSET_FROM_EXTRUDER -10   // Z probe to nozzle Y offset: -front +behind
+  #define Z_PROBE_OFFSET_FROM_EXTRUDER -3.5  // Z probe to nozzle Z offset: -below (always!)
 
-  #define Z_RAISE_BEFORE_HOMING 4       // (in mm) Raise Z before homing (G28) for Probe Clearance.
-                                        // Be sure you have this distance over your Z_MAX_POS in case
+  #define Z_RAISE_BEFORE_HOMING 4       // (in mm) Raise Z axis before homing (G28) for Z probe clearance.
+                                        // Be sure you have this distance over your Z_MAX_POS in case.
 
-  #define XY_TRAVEL_SPEED 4000         // X and Y axis travel speed between probes, in mm/min
+  #define XY_TRAVEL_SPEED 4000         // X and Y axis travel speed between probes, in mm/min.
 
-  #define Z_RAISE_BEFORE_PROBING 15   //How much the extruder will be raised before traveling to the first probing point.
-  #define Z_RAISE_BETWEEN_PROBINGS 5  //How much the extruder will be raised when traveling from between next probing points
-  #define Z_RAISE_AFTER_PROBING 50    //How much the extruder will be raised after the last probing point.
+  #define Z_RAISE_BEFORE_PROBING 15   // How much the Z axis will be raised before traveling to the first probing point.
+  #define Z_RAISE_BETWEEN_PROBINGS 5  // How much the Z axis will be raised when traveling from between next probing points.
+  #define Z_RAISE_AFTER_PROBING 50    // How much the Z axis will be raised after the last probing point.
 
-//   #define Z_PROBE_END_SCRIPT "G1 Z10 F12000\nG1 X15 Y330\nG1 Z0.5\nG1 Z10" //These commands will be executed in the end of G29 routine.
-                                                                            //Useful to retract a deployable probe.
+//   #define Z_PROBE_END_SCRIPT "G1 Z10 F12000\nG1 X15 Y330\nG1 Z0.5\nG1 Z10" // These commands will be executed in the end of G29 routine.
+                                                                            // Useful to retract a deployable Z probe.
 
-  //#define Z_PROBE_SLED // turn on if you have a z-probe mounted on a sled like those designed by Charles Bell
-  //#define SLED_DOCKING_OFFSET 5 // the extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
+  //#define Z_PROBE_SLED // Turn on if you have a Z probe mounted on a sled like those designed by Charles Bell.
+  //#define SLED_DOCKING_OFFSET 5 // The extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
 
-  // Allen key retractable z-probe as seen on many Kossel delta printers - http://reprap.org/wiki/Kossel#Automatic_bed_leveling_probe
+  // Allen key retractable Z probe as seen on many Kossel delta printers - http://reprap.org/wiki/Kossel#Automatic_bed_leveling_probe
   // Deploys by touching z-axis belt. Retracts by pushing the probe down. Uses Z_MIN_PIN.
   //#define Z_PROBE_ALLEN_KEY
 
     #define Z_PROBE_ALLEN_KEY_STOW_3_FEEDRATE HOMING_FEEDRATE_Z
   #endif
 
-//If you have enabled the Bed Auto Leveling and are using the same Z Probe for Z Homing,
-//it is highly recommended you let this Z_SAFE_HOMING enabled!!!
+// If you have enabled the bed auto leveling and are using the same Z probe for Z homing,
+// it is highly recommended you let this Z_SAFE_HOMING enabled!!!
 
-  #define Z_SAFE_HOMING   // This feature is meant to avoid Z homing with probe outside the bed area.
+  #define Z_SAFE_HOMING   // This feature is meant to avoid Z homing with Z probe outside the bed area.
                           // When defined, it will:
-                          // - Allow Z homing only after X and Y homing AND stepper drivers still enabled
-                          // - If stepper drivers timeout, it will need X and Y homing again before Z homing
-                          // - Position the probe in a defined XY point before Z Homing when homing all axis (G28)
-                          // - Block Z homing only when the probe is outside bed area.
+                          // - Allow Z homing only after X and Y homing AND stepper drivers still enabled.
+                          // - If stepper drivers timeout, it will need X and Y homing again before Z homing.
+                          // - Position the Z probe in a defined XY point before Z Homing when homing all axis (G28).
+                          // - Block Z homing only when the Z probe is outside bed area.
 
   #if ENABLED(Z_SAFE_HOMING)
 
-    #define Z_SAFE_HOMING_X_POINT ((X_MIN_POS + X_MAX_POS) / 2)    // X point for Z homing when homing all axis (G28)
-    #define Z_SAFE_HOMING_Y_POINT ((Y_MIN_POS + Y_MAX_POS) / 2)    // Y point for Z homing when homing all axis (G28)
+    #define Z_SAFE_HOMING_X_POINT ((X_MIN_POS + X_MAX_POS) / 2)    // X point for Z homing when homing all axis (G28).
+    #define Z_SAFE_HOMING_Y_POINT ((Y_MIN_POS + Y_MAX_POS) / 2)    // Y point for Z homing when homing all axis (G28).
 
   #endif
 
-  // Support for a dedicated Z PROBE endstop separate from the Z MIN endstop.
-  // If you would like to use both a Z PROBE and a Z MIN endstop together , uncomment #define Z_MIN_PROBE_ENDSTOP and read the instructions below.
-  // If you want to still use the Z min endstop for homing, disable Z_SAFE_HOMING above. Eg; to park the head outside the bed area when homing with G28.
-  // WARNING: The Z MIN endstop will need to set properly as it would without a Z PROBE to prevent head crashes and premature stopping during a print.
-  // To use a separate Z PROBE endstop, you must have a Z_MIN_PROBE_PIN defined in the pins.h file for your control board.
-  // If you are using a servo based Z PROBE, you will need to enable NUM_SERVOS, Z_ENDSTOP_SERVO_NR and SERVO_ENDSTOP_ANGLES in the R/C Servo below.
-  // RAMPS 1.3/1.4 boards may be able to use the 5V, Ground and the D32 pin in the Aux 4 section of the RAMPS board. Use 5V for powered sensors, otherwise connect to ground and D32
-  // for normally closed configuration and 5V and D32 for normally open configurations. Normally closed configuration is advised and assumed.
-  // The D32 pin in Aux 4 on RAMPS maps to the Arduino D32 pin. Z_MIN_PROBE_PIN is setting the pin to use on the Arduino. Since the D32 pin on the RAMPS maps to D32 on Arduino, this works.
-  // D32 is currently selected in the RAMPS 1.3/1.4 pin file. All other boards will need changes to the respective pins_XXXXX.h file.
-  // WARNING: Setting the wrong pin may have unexpected and potentially disastrous outcomes. Use with caution and do your homework.
-
+  // Support for a dedicated Z probe endstop separate from the Z min endstop.
+  // If you would like to use both a Z probe and a Z min endstop together,
+  // uncomment #define Z_MIN_PROBE_ENDSTOP and read the instructions below.
+  // If you still want to use the Z min endstop for homing, disable Z_SAFE_HOMING above.
+  // Example: To park the head outside the bed area when homing with G28.
+  //
+  // WARNING:
+  // The Z min endstop will need to set properly as it would without a Z probe
+  // to prevent head crashes and premature stopping during a print.
+  //
+  // To use a separate Z probe endstop, you must have a Z_MIN_PROBE_PIN
+  // defined in the pins_XXXXX.h file for your control board.
+  // If you are using a servo based Z probe, you will need to enable NUM_SERVOS,
+  // Z_ENDSTOP_SERVO_NR and SERVO_ENDSTOP_ANGLES in the R/C SERVO support below.
+  // RAMPS 1.3/1.4 boards may be able to use the 5V, Ground and the D32 pin
+  // in the Aux 4 section of the RAMPS board. Use 5V for powered sensors,
+  // otherwise connect to ground and D32 for normally closed configuration
+  // and 5V and D32 for normally open configurations.
+  // Normally closed configuration is advised and assumed.
+  // The D32 pin in Aux 4 on RAMPS maps to the Arduino D32 pin.
+  // Z_MIN_PROBE_PIN is setting the pin to use on the Arduino.
+  // Since the D32 pin on the RAMPS maps to D32 on Arduino, this works.
+  // D32 is currently selected in the RAMPS 1.3/1.4 pin file.
+  // All other boards will need changes to the respective pins_XXXXX.h file.
+  //
+  // WARNING:
+  // Setting the wrong pin may have unexpected and potentially disastrous outcomes.
+  // Use with caution and do your homework.
+  //
   //#define Z_MIN_PROBE_ENDSTOP
 
 #endif // ENABLE_AUTO_BED_LEVELING
   #define EEPROM_CHITCHAT // Please keep turned on if you can.
 #endif
 
+//
+// M100 Free Memory Watcher
+//
+//#define M100_FREE_MEMORY_WATCHER // uncomment to add the M100 Free Memory Watcher for debug purpose
+
 // @section temperature
 
 // Preheat Constants
 // Servo Endstops
 //
 // This allows for servo actuated endstops, primary usage is for the Z Axis to eliminate calibration or bed height changes.
-// Use M851 to set the z-probe vertical offset from the nozzle. Store that setting with M500.
+// Use M851 to set the Z probe vertical offset from the nozzle. Store that setting with M500.
 //
 //#define X_ENDSTOP_SERVO_NR 1
 //#define Y_ENDSTOP_SERVO_NR 2

Marlin/example_configurations/delta/generic/Configuration.h

 const bool Z_MAX_ENDSTOP_INVERTING = true; // set to true to invert the logic of the endstop.
 const bool Z_MIN_PROBE_ENDSTOP_INVERTING = true; // set to true to invert the logic of the endstop.
 //#define DISABLE_MAX_ENDSTOPS
-#define DISABLE_MIN_ENDSTOPS // Deltas only use min endstops for probing
+#define DISABLE_MIN_ENDSTOPS // Deltas only use min endstops for probing.
 
-// If you want to enable the Z Probe pin, but disable its use, uncomment the line below.
-// This only affects a Z Probe Endstop if you have separate Z min endstop as well and have
-// activated Z_MIN_PROBE_ENDSTOP below. If you are using the Z Min endstop on your Z Probe,
+// If you want to enable the Z probe pin, but disable its use, uncomment the line below.
+// This only affects a Z probe endstop if you have separate Z min endstop as well and have
+// activated Z_MIN_PROBE_ENDSTOP below. If you are using the Z Min endstop on your Z probe,
 // this has no effect.
 //#define DISABLE_Z_MIN_PROBE_ENDSTOP
 
 //=========================== Manual Bed Leveling ===========================
 //===========================================================================
 
-// #define MANUAL_BED_LEVELING  // Add display menu option for bed leveling
-// #define MESH_BED_LEVELING    // Enable mesh bed leveling
+// #define MANUAL_BED_LEVELING  // Add display menu option for bed leveling.
+// #define MESH_BED_LEVELING    // Enable mesh bed leveling.
 
 #if ENABLED(MANUAL_BED_LEVELING)
-  #define MBL_Z_STEP 0.025  // Step size while manually probing Z axis
+  #define MBL_Z_STEP 0.025  // Step size while manually probing Z axis.
 #endif  // MANUAL_BED_LEVELING
 
 #if ENABLED(MESH_BED_LEVELING)
   #define MESH_MAX_X (X_MAX_POS - MESH_MIN_X)
   #define MESH_MIN_Y 10
   #define MESH_MAX_Y (Y_MAX_POS - MESH_MIN_Y)
-  #define MESH_NUM_X_POINTS 3  // Don't use more than 7 points per axis, implementation limited
+  #define MESH_NUM_X_POINTS 3  // Don't use more than 7 points per axis, implementation limited.
   #define MESH_NUM_Y_POINTS 3
-  #define MESH_HOME_SEARCH_Z 4  // Z after Home, bed somewhere below but above 0.0
+  #define MESH_HOME_SEARCH_Z 4  // Z after Home, bed somewhere below but above 0.0.
 #endif  // MESH_BED_LEVELING
 
 //===========================================================================
 
 // @section bedlevel
 
-//#define ENABLE_AUTO_BED_LEVELING // Delete the comment to enable (remove // at the start of the line)
-//#define Z_MIN_PROBE_REPEATABILITY_TEST // Z-Probe Repeatability test is not supported in Deltas yet.
+//#define ENABLE_AUTO_BED_LEVELING // Delete the comment to enable (remove // at the start of the line).
+//#define Z_MIN_PROBE_REPEATABILITY_TEST // Z probe repeatability test is not supported in Deltas yet.
 
 #if ENABLED(ENABLE_AUTO_BED_LEVELING)
 
-  // There are 2 different ways to specify probing locations
+  // There are 2 different ways to specify probing locations.
   //
   // - "grid" mode
   //   Probe several points in a rectangular grid.
   //   Probe 3 arbitrary points on the bed (that aren't colinear)
   //   You specify the XY coordinates of all 3 points.
 
-  // Enable this to sample the bed in a grid (least squares solution)
-  // Note: this feature generates 10KB extra code size
-  #define AUTO_BED_LEVELING_GRID  // Deltas only support grid mode
+  // Enable this to sample the bed in a grid (least squares solution).
+  // Note: this feature generates 10KB extra code size.
+  #define AUTO_BED_LEVELING_GRID  // Deltas only support grid mode.
 
   #if ENABLED(AUTO_BED_LEVELING_GRID)
 
     #define FRONT_PROBE_BED_POSITION -DELTA_PROBABLE_RADIUS
     #define BACK_PROBE_BED_POSITION DELTA_PROBABLE_RADIUS
 
-    #define MIN_PROBE_EDGE 10 // The probe square sides can be no smaller than this
+    #define MIN_PROBE_EDGE 10 // The Z probe square sides can be no smaller than this.
 
     // Non-linear bed leveling will be used.
     // Compensate by interpolating between the nearest four Z probe values for each point.
 
   #else  // !AUTO_BED_LEVELING_GRID
 
-      // Arbitrary points to probe. A simple cross-product
-      // is used to estimate the plane of the bed.
+      // Arbitrary points to probe.
+      // A simple cross-product is used to estimate the plane of the bed.
       #define ABL_PROBE_PT_1_X 15
       #define ABL_PROBE_PT_1_Y 180
       #define ABL_PROBE_PT_2_X 15
 
   #endif // AUTO_BED_LEVELING_GRID
 
-  // Offsets to the probe relative to the extruder tip (Hotend - Probe)
-  // X and Y offsets must be integers
-  #define X_PROBE_OFFSET_FROM_EXTRUDER 0     // Probe on: -left  +right
-  #define Y_PROBE_OFFSET_FROM_EXTRUDER -10   // Probe on: -front +behind
-  #define Z_PROBE_OFFSET_FROM_EXTRUDER -3.5  // -below (always!)
+  // Offsets to the Z probe relative to the nozzle tip.
+  // X and Y offsets must be integers.
+  #define X_PROBE_OFFSET_FROM_EXTRUDER 0     // Z probe to nozzle X offset: -left  +right
+  #define Y_PROBE_OFFSET_FROM_EXTRUDER -10   // Z probe to nozzle Y offset: -front +behind
+  #define Z_PROBE_OFFSET_FROM_EXTRUDER -3.5  // Z probe to nozzle Z offset: -below (always!)
 
-  #define Z_RAISE_BEFORE_HOMING 4       // (in mm) Raise Z before homing (G28) for Probe Clearance.
-                                        // Be sure you have this distance over your Z_MAX_POS in case
+  #define Z_RAISE_BEFORE_HOMING 4       // (in mm) Raise Z axis before homing (G28) for Z probe clearance.
+                                        // Be sure you have this distance over your Z_MAX_POS in case.
 
-  #define XY_TRAVEL_SPEED 4000         // X and Y axis travel speed between probes, in mm/min
+  #define XY_TRAVEL_SPEED 4000         // X and Y axis travel speed between probes, in mm/min.
 
-  #define Z_RAISE_BEFORE_PROBING 15   //How much the extruder will be raised before traveling to the first probing point.
-  #define Z_RAISE_BETWEEN_PROBINGS 5  //How much the extruder will be raised when traveling from between next probing points
-  #define Z_RAISE_AFTER_PROBING 50    //How much the extruder will be raised after the last probing point.
+  #define Z_RAISE_BEFORE_PROBING 15   // How much the Z axis will be raised before traveling to the first probing point.
+  #define Z_RAISE_BETWEEN_PROBINGS 5  // How much the Z axis will be raised when traveling from between next probing points
+  #define Z_RAISE_AFTER_PROBING 50    // How much the Z axis will be raised after the last probing point.
 
-//   #define Z_PROBE_END_SCRIPT "G1 Z10 F12000\nG1 X15 Y330\nG1 Z0.5\nG1 Z10" //These commands will be executed in the end of G29 routine.
-                                                                            //Useful to retract a deployable probe.
+//   #define Z_PROBE_END_SCRIPT "G1 Z10 F12000\nG1 X15 Y330\nG1 Z0.5\nG1 Z10" // These commands will be executed in the end of G29 routine.
+                                                                            // Useful to retract a deployable Z probe.
 
-  //#define Z_PROBE_SLED // turn on if you have a z-probe mounted on a sled like those designed by Charles Bell
-  //#define SLED_DOCKING_OFFSET 5 // the extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
+  //#define Z_PROBE_SLED // Turn on if you have a Z probe mounted on a sled like those designed by Charles Bell.
+  //#define SLED_DOCKING_OFFSET 5 // The extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
 
   // Allen key retractable z-probe as seen on many Kossel delta printers - http://reprap.org/wiki/Kossel#Automatic_bed_leveling_probe
   // Deploys by touching z-axis belt. Retracts by pushing the probe down. Uses Z_MIN_PIN.
     //#define Z_PROBE_ALLEN_KEY_STOW_3_FEEDRATE HOMING_FEEDRATE_Z
   #endif
 
-//If you have enabled the Bed Auto Leveling and are using the same Z Probe for Z Homing,
-//it is highly recommended you let this Z_SAFE_HOMING enabled!!!
+// If you have enabled the bed auto leveling and are using the same Z probe for Z homing,
+// it is highly recommended you let this Z_SAFE_HOMING enabled!!!
 
-  #define Z_SAFE_HOMING   // This feature is meant to avoid Z homing with probe outside the bed area.
+  #define Z_SAFE_HOMING   // This feature is meant to avoid Z homing with Z probe outside the bed area.
                           // When defined, it will:
-                          // - Allow Z homing only after X and Y homing AND stepper drivers still enabled
-                          // - If stepper drivers timeout, it will need X and Y homing again before Z homing
-                          // - Position the probe in a defined XY point before Z Homing when homing all axis (G28)
-                          // - Block Z homing only when the probe is outside bed area.
+                          // - Allow Z homing only after X and Y homing AND stepper drivers still enabled.
+                          // - If stepper drivers timeout, it will need X and Y homing again before Z homing.
+                          // - Position the Z probe in a defined XY point before Z Homing when homing all axis (G28).
+                          // - Block Z homing only when the Z probe is outside bed area.
 
   #if ENABLED(Z_SAFE_HOMING)
 
-    #define Z_SAFE_HOMING_X_POINT ((X_MIN_POS + X_MAX_POS) / 2)    // X point for Z homing when homing all axis (G28)
-    #define Z_SAFE_HOMING_Y_POINT ((Y_MIN_POS + Y_MAX_POS) / 2)    // Y point for Z homing when homing all axis (G28)
+    #define Z_SAFE_HOMING_X_POINT ((X_MIN_POS + X_MAX_POS) / 2)    // X point for Z homing when homing all axis (G28).
+    #define Z_SAFE_HOMING_Y_POINT ((Y_MIN_POS + Y_MAX_POS) / 2)    // Y point for Z homing when homing all axis (G28).
 
   #endif
 
-  // Support for a dedicated Z PROBE endstop separate from the Z MIN endstop.
-  // If you would like to use both a Z PROBE and a Z MIN endstop together , uncomment #define Z_MIN_PROBE_ENDSTOP and read the instructions below.
-  // If you want to still use the Z min endstop for homing, disable Z_SAFE_HOMING above. Eg; to park the head outside the bed area when homing with G28.
-  // WARNING: The Z MIN endstop will need to set properly as it would without a Z PROBE to prevent head crashes and premature stopping during a print.
-  // To use a separate Z PROBE endstop, you must have a Z_MIN_PROBE_PIN defined in the pins.h file for your control board.
-  // If you are using a servo based Z PROBE, you will need to enable NUM_SERVOS, Z_ENDSTOP_SERVO_NR and SERVO_ENDSTOP_ANGLES in the R/C Servo below.
-  // RAMPS 1.3/1.4 boards may be able to use the 5V, Ground and the D32 pin in the Aux 4 section of the RAMPS board. Use 5V for powered sensors, otherwise connect to ground and D32
-  // for normally closed configuration and 5V and D32 for normally open configurations. Normally closed configuration is advised and assumed.
-  // The D32 pin in Aux 4 on RAMPS maps to the Arduino D32 pin. Z_MIN_PROBE_PIN is setting the pin to use on the Arduino. Since the D32 pin on the RAMPS maps to D32 on Arduino, this works.
-  // D32 is currently selected in the RAMPS 1.3/1.4 pin file. All other boards will need changes to the respective pins_XXXXX.h file.
-  // WARNING: Setting the wrong pin may have unexpected and potentially disastrous outcomes. Use with caution and do your homework.
-
+  // Support for a dedicated Z probe endstop separate from the Z min endstop.
+  // If you would like to use both a Z probe and a Z min endstop together,
+  // uncomment #define Z_MIN_PROBE_ENDSTOP and read the instructions below.
+  // If you still want to use the Z min endstop for homing, disable Z_SAFE_HOMING above.
+  // Example: To park the head outside the bed area when homing with G28.
+  //
+  // WARNING:
+  // The Z min endstop will need to set properly as it would without a Z probe
+  // to prevent head crashes and premature stopping during a print.
+  //
+  // To use a separate Z probe endstop, you must have a Z_MIN_PROBE_PIN
+  // defined in the pins_XXXXX.h file for your control board.
+  // If you are using a servo based Z probe, you will need to enable NUM_SERVOS,
+  // Z_ENDSTOP_SERVO_NR and SERVO_ENDSTOP_ANGLES in the R/C SERVO support below.
+  // RAMPS 1.3/1.4 boards may be able to use the 5V, Ground and the D32 pin
+  // in the Aux 4 section of the RAMPS board. Use 5V for powered sensors,
+  // otherwise connect to ground and D32 for normally closed configuration
+  // and 5V and D32 for normally open configurations.
+  // Normally closed configuration is advised and assumed.
+  // The D32 pin in Aux 4 on RAMPS maps to the Arduino D32 pin.
+  // Z_MIN_PROBE_PIN is setting the pin to use on the Arduino.
+  // Since the D32 pin on the RAMPS maps to D32 on Arduino, this works.
+  // D32 is currently selected in the RAMPS 1.3/1.4 pin file.
+  // All other boards will need changes to the respective pins_XXXXX.h file.
+  //
+  // WARNING:
+  // Setting the wrong pin may have unexpected and potentially disastrous outcomes.
+  // Use with caution and do your homework.
+  //
   //#define Z_MIN_PROBE_ENDSTOP
 
 #endif // ENABLE_AUTO_BED_LEVELING
   #define EEPROM_CHITCHAT // Please keep turned on if you can.
 #endif
 
+//
+// M100 Free Memory Watcher
+//
+//#define M100_FREE_MEMORY_WATCHER // uncomment to add the M100 Free Memory Watcher for debug purpose
+
 // @section temperature
 
 // Preheat Constants
 // Servo Endstops
 //
 // This allows for servo actuated endstops, primary usage is for the Z Axis to eliminate calibration or bed height changes.
-// Use M851 to set the z-probe vertical offset from the nozzle. Store that setting with M500.
+// Use M851 to set the Z probe vertical offset from the nozzle. Store that setting with M500.
 //
 //#define X_ENDSTOP_SERVO_NR 1
 //#define Y_ENDSTOP_SERVO_NR 2

Marlin/example_configurations/delta/kossel_mini/Configuration.h

 const bool Z_MAX_ENDSTOP_INVERTING = false; // set to true to invert the logic of the endstop.
 const bool Z_MIN_PROBE_ENDSTOP_INVERTING = false; // set to true to invert the logic of the endstop.
 //#define DISABLE_MAX_ENDSTOPS
-//#define DISABLE_MIN_ENDSTOPS // Deltas only use min endstops for probing
+//#define DISABLE_MIN_ENDSTOPS // Deltas only use min endstops for probing.
 
-// If you want to enable the Z Probe pin, but disable its use, uncomment the line below.
-// This only affects a Z Probe Endstop if you have separate Z min endstop as well and have
-// activated Z_MIN_PROBE_ENDSTOP below. If you are using the Z Min endstop on your Z Probe,
+// If you want to enable the Z probe pin, but disable its use, uncomment the line below.
+// This only affects a Z probe endstop if you have separate Z min endstop as well and have
+// activated Z_MIN_PROBE_ENDSTOP below. If you are using the Z Min endstop on your Z probe,
 // this has no effect.
 //#define DISABLE_Z_MIN_PROBE_ENDSTOP
 
 //=========================== Manual Bed Leveling ===========================
 //===========================================================================
 
-// #define MANUAL_BED_LEVELING  // Add display menu option for bed leveling
-// #define MESH_BED_LEVELING    // Enable mesh bed leveling
+// #define MANUAL_BED_LEVELING  // Add display menu option for bed leveling.
+// #define MESH_BED_LEVELING    // Enable mesh bed leveling.
 
 #if ENABLED(MANUAL_BED_LEVELING)
-  #define MBL_Z_STEP 0.025  // Step size while manually probing Z axis
+  #define MBL_Z_STEP 0.025  // Step size while manually probing Z axis.
 #endif  // MANUAL_BED_LEVELING
 
 #if ENABLED(MESH_BED_LEVELING)
   #define MESH_MAX_X (X_MAX_POS - MESH_MIN_X)
   #define MESH_MIN_Y 10
   #define MESH_MAX_Y (Y_MAX_POS - MESH_MIN_Y)
-  #define MESH_NUM_X_POINTS 3  // Don't use more than 7 points per axis, implementation limited
+  #define MESH_NUM_X_POINTS 3  // Don't use more than 7 points per axis, implementation limited.
   #define MESH_NUM_Y_POINTS 3
-  #define MESH_HOME_SEARCH_Z 4  // Z after Home, bed somewhere below but above 0.0
+  #define MESH_HOME_SEARCH_Z 4  // Z after Home, bed somewhere below but above 0.0.
 #endif  // MESH_BED_LEVELING
 
 //===========================================================================
 
 // @section bedlevel
 
-#define ENABLE_AUTO_BED_LEVELING // Delete the comment to enable (remove // at the start of the line)
-//#define Z_MIN_PROBE_REPEATABILITY_TEST // Z-Probe Repeatability test is not supported in Deltas yet.
+#define ENABLE_AUTO_BED_LEVELING // Delete the comment to enable (remove // at the start of the line).
+//#define Z_MIN_PROBE_REPEATABILITY_TEST // Z probe repeatability test is not supported in Deltas yet.
 
 #if ENABLED(ENABLE_AUTO_BED_LEVELING)
 
-  // There are 2 different ways to specify probing locations
+  // There are 2 different ways to specify probing locations:
   //
   // - "grid" mode
   //   Probe several points in a rectangular grid.
   //   Probe 3 arbitrary points on the bed (that aren't colinear)
   //   You specify the XY coordinates of all 3 points.
 
-  // Enable this to sample the bed in a grid (least squares solution)
-  // Note: this feature generates 10KB extra code size
-  #define AUTO_BED_LEVELING_GRID  // Deltas only support grid mode
+  // Enable this to sample the bed in a grid (least squares solution).
+  // Note: this feature generates 10KB extra code size.
+  #define AUTO_BED_LEVELING_GRID  // Deltas only support grid mode.
 
   #if ENABLED(AUTO_BED_LEVELING_GRID)
 
     #define FRONT_PROBE_BED_POSITION -DELTA_PROBABLE_RADIUS
     #define BACK_PROBE_BED_POSITION DELTA_PROBABLE_RADIUS
 
-    #define MIN_PROBE_EDGE 10 // The probe square sides can be no smaller than this
+    #define MIN_PROBE_EDGE 10 // The Z probe square sides can be no smaller than this.
 
     // Non-linear bed leveling will be used.
     // Compensate by interpolating between the nearest four Z probe values for each point.
 
   #else  // !AUTO_BED_LEVELING_GRID
 
-      // Arbitrary points to probe. A simple cross-product
-      // is used to estimate the plane of the bed.
+      // Arbitrary points to probe.
+      // A simple cross-product is used to estimate the plane of the bed.
       #define ABL_PROBE_PT_1_X 15
       #define ABL_PROBE_PT_1_Y 180
       #define ABL_PROBE_PT_2_X 15
 
   #endif // AUTO_BED_LEVELING_GRID
 
-  // Offsets to the probe relative to the extruder tip (Hotend - Probe)
-  // X and Y offsets must be integers
-  #define X_PROBE_OFFSET_FROM_EXTRUDER 0     // Probe on: -left  +right
-  #define Y_PROBE_OFFSET_FROM_EXTRUDER -10   // Probe on: -front +behind
-  #define Z_PROBE_OFFSET_FROM_EXTRUDER -3.5  // -below (always!)
+  // Offsets to the Z probe relative to the nozzle tip.
+  // X and Y offsets must be integers.
+  #define X_PROBE_OFFSET_FROM_EXTRUDER 0     // Z probe to nozzle X offset: -left  +right
+  #define Y_PROBE_OFFSET_FROM_EXTRUDER -10   // Z probe to nozzle Y offset: -front +behind
+  #define Z_PROBE_OFFSET_FROM_EXTRUDER -3.5  // Z probe to nozzle Z offset: -below (always!)
 
-  #define Z_RAISE_BEFORE_HOMING 15      // (in mm) Raise Z before homing (G28) for Probe Clearance.
-                                        // Be sure you have this distance over your Z_MAX_POS in case
+  #define Z_RAISE_BEFORE_HOMING 15      // (in mm) Raise Z axis before homing (G28) for Z probe clearance.
+                                        // Be sure you have this distance over your Z_MAX_POS in case.
 
-  #define XY_TRAVEL_SPEED 4000         // X and Y axis travel speed between probes, in mm/min
+  #define XY_TRAVEL_SPEED 4000         // X and Y axis travel speed between probes, in mm/min.
 
-  #define Z_RAISE_BEFORE_PROBING 15   //How much the extruder will be raised before traveling to the first probing point.
-  #define Z_RAISE_BETWEEN_PROBINGS 5  //How much the extruder will be raised when traveling from between next probing points
-  #define Z_RAISE_AFTER_PROBING 50    //How much the extruder will be raised after the last probing point.
+  #define Z_RAISE_BEFORE_PROBING 15   // How much the Z axis will be raised before traveling to the first probing point.
+  #define Z_RAISE_BETWEEN_PROBINGS 5  // How much the Z axis will be raised when traveling from between next probing points
+  #define Z_RAISE_AFTER_PROBING 50    // How much the Z axis will be raised after the last probing point.
 
-//   #define Z_PROBE_END_SCRIPT "G1 Z10 F12000\nG1 X15 Y330\nG1 Z0.5\nG1 Z10" //These commands will be executed in the end of G29 routine.
-                                                                            //Useful to retract a deployable probe.
+//   #define Z_PROBE_END_SCRIPT "G1 Z10 F12000\nG1 X15 Y330\nG1 Z0.5\nG1 Z10" // These commands will be executed in the end of G29 routine.
+                                                                            // Useful to retract a deployable Z probe.
 
-  //#define Z_PROBE_SLED // turn on if you have a z-probe mounted on a sled like those designed by Charles Bell
-  //#define SLED_DOCKING_OFFSET 5 // the extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
+  //#define Z_PROBE_SLED // Turn on if you have a Z probe mounted on a sled like those designed by Charles Bell.
+  //#define SLED_DOCKING_OFFSET 5 // The extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
 
   // Allen key retractable z-probe as seen on many Kossel delta printers - http://reprap.org/wiki/Kossel#Automatic_bed_leveling_probe
   // Deploys by touching z-axis belt. Retracts by pushing the probe down. Uses Z_MIN_PIN.
     //#define Z_PROBE_ALLEN_KEY_STOW_3_FEEDRATE HOMING_FEEDRATE_Z
   #endif
 
-//If you have enabled the Bed Auto Leveling and are using the same Z Probe for Z Homing,
-//it is highly recommended you let this Z_SAFE_HOMING enabled!!!
+// If you have enabled the bed auto leveling and are using the same Z probe for Z homing,
+// it is highly recommended you let this Z_SAFE_HOMING enabled!!!
 
-  #define Z_SAFE_HOMING   // This feature is meant to avoid Z homing with probe outside the bed area.
+  #define Z_SAFE_HOMING   // This feature is meant to avoid Z homing with Z probe outside the bed area.
                           // When defined, it will:
-                          // - Allow Z homing only after X and Y homing AND stepper drivers still enabled
-                          // - If stepper drivers timeout, it will need X and Y homing again before Z homing
-                          // - Position the probe in a defined XY point before Z Homing when homing all axis (G28)
-                          // - Block Z homing only when the probe is outside bed area.
+                          // - Allow Z homing only after X and Y homing AND stepper drivers still enabled.
+                          // - If stepper drivers timeout, it will need X and Y homing again before Z homing.
+                          // - Position the Z probe in a defined XY point before Z Homing when homing all axis (G28).
+                          // - Block Z homing only when the Z probe is outside bed area.
 
   #if ENABLED(Z_SAFE_HOMING)
 
-    #define Z_SAFE_HOMING_X_POINT ((X_MIN_POS + X_MAX_POS) / 2)    // X point for Z homing when homing all axis (G28)
-    #define Z_SAFE_HOMING_Y_POINT ((Y_MIN_POS + Y_MAX_POS) / 2)    // Y point for Z homing when homing all axis (G28)
+    #define Z_SAFE_HOMING_X_POINT ((X_MIN_POS + X_MAX_POS) / 2)    // X point for Z homing when homing all axis (G28).
+    #define Z_SAFE_HOMING_Y_POINT ((Y_MIN_POS + Y_MAX_POS) / 2)    // Y point for Z homing when homing all axis (G28).
 
   #endif
 
-  // Support for a dedicated Z PROBE endstop separate from the Z MIN endstop.
-  // If you would like to use both a Z PROBE and a Z MIN endstop together , uncomment #define Z_MIN_PROBE_ENDSTOP and read the instructions below.
-  // If you want to still use the Z min endstop for homing, disable Z_SAFE_HOMING above. Eg; to park the head outside the bed area when homing with G28.
-  // WARNING: The Z MIN endstop will need to set properly as it would without a Z PROBE to prevent head crashes and premature stopping during a print.
-  // To use a separate Z PROBE endstop, you must have a Z_MIN_PROBE_PIN defined in the pins.h file for your control board.
-  // If you are using a servo based Z PROBE, you will need to enable NUM_SERVOS, Z_ENDSTOP_SERVO_NR and SERVO_ENDSTOP_ANGLES in the R/C Servo below.
-  // RAMPS 1.3/1.4 boards may be able to use the 5V, Ground and the D32 pin in the Aux 4 section of the RAMPS board. Use 5V for powered sensors, otherwise connect to ground and D32
-  // for normally closed configuration and 5V and D32 for normally open configurations. Normally closed configuration is advised and assumed.
-  // The D32 pin in Aux 4 on RAMPS maps to the Arduino D32 pin. Z_MIN_PROBE_PIN is setting the pin to use on the Arduino. Since the D32 pin on the RAMPS maps to D32 on Arduino, this works.
-  // D32 is currently selected in the RAMPS 1.3/1.4 pin file. All other boards will need changes to the respective pins_XXXXX.h file.
-  // WARNING: Setting the wrong pin may have unexpected and potentially disastrous outcomes. Use with caution and do your homework.
-
+  // Support for a dedicated Z probe endstop separate from the Z min endstop.
+  // If you would like to use both a Z probe and a Z min endstop together,
+  // uncomment #define Z_MIN_PROBE_ENDSTOP and read the instructions below.
+  // If you still want to use the Z min endstop for homing, disable Z_SAFE_HOMING above.
+  // Example: To park the head outside the bed area when homing with G28.
+  //
+  // WARNING:
+  // The Z min endstop will need to set properly as it would without a Z probe
+  // to prevent head crashes and premature stopping during a print.
+  //
+  // To use a separate Z probe endstop, you must have a Z_MIN_PROBE_PIN
+  // defined in the pins_XXXXX.h file for your control board.
+  // If you are using a servo based Z probe, you will need to enable NUM_SERVOS,
+  // Z_ENDSTOP_SERVO_NR and SERVO_ENDSTOP_ANGLES in the R/C SERVO support below.
+  // RAMPS 1.3/1.4 boards may be able to use the 5V, Ground and the D32 pin
+  // in the Aux 4 section of the RAMPS board. Use 5V for powered sensors,
+  // otherwise connect to ground and D32 for normally closed configuration
+  // and 5V and D32 for normally open configurations.
+  // Normally closed configuration is advised and assumed.
+  // The D32 pin in Aux 4 on RAMPS maps to the Arduino D32 pin.
+  // Z_MIN_PROBE_PIN is setting the pin to use on the Arduino.
+  // Since the D32 pin on the RAMPS maps to D32 on Arduino, this works.
+  // D32 is currently selected in the RAMPS 1.3/1.4 pin file.
+  // All other boards will need changes to the respective pins_XXXXX.h file.
+  //
+  // WARNING:
+  // Setting the wrong pin may have unexpected and potentially disastrous outcomes.
+  // Use with caution and do your homework.
+  //
   //#define Z_MIN_PROBE_ENDSTOP
 
 #endif // ENABLE_AUTO_BED_LEVELING
   #define EEPROM_CHITCHAT // Please keep turned on if you can.
 #endif
 
+//
+// M100 Free Memory Watcher
+//
+//#define M100_FREE_MEMORY_WATCHER // uncomment to add the M100 Free Memory Watcher for debug purpose
+
 // @section temperature
 
 // Preheat Constants
 // Servo Endstops
 //
 // This allows for servo actuated endstops, primary usage is for the Z Axis to eliminate calibration or bed height changes.
-// Use M851 to set the z-probe vertical offset from the nozzle. Store that setting with M500.
+// Use M851 to set the Z probe vertical offset from the nozzle. Store that setting with M500.
 //
 //#define X_ENDSTOP_SERVO_NR 1
 //#define Y_ENDSTOP_SERVO_NR 2

Marlin/example_configurations/delta/kossel_pro/Configuration.h

 const bool Z_MAX_ENDSTOP_INVERTING = false; // set to true to invert the logic of the endstop.
 const bool Z_MIN_PROBE_ENDSTOP_INVERTING = false; // set to true to invert the logic of the endstop.
 //#define DISABLE_MAX_ENDSTOPS
-//#define DISABLE_MIN_ENDSTOPS // Deltas only use min endstops for probing
+//#define DISABLE_MIN_ENDSTOPS // Deltas only use min endstops for probing.
 
-// If you want to enable the Z Probe pin, but disable its use, uncomment the line below.
-// This only affects a Z Probe Endstop if you have separate Z min endstop as well and have
-// activated Z_MIN_PROBE_ENDSTOP below. If you are using the Z Min endstop on your Z Probe,
+// If you want to enable the Z probe pin, but disable its use, uncomment the line below.
+// This only affects a Z probe endstop if you have separate Z min endstop as well and have
+// activated Z_MIN_PROBE_ENDSTOP below. If you are using the Z Min endstop on your Z probe,
 // this has no effect.
 //#define DISABLE_Z_MIN_PROBE_ENDSTOP
 
 //=========================== Manual Bed Leveling ===========================
 //===========================================================================
 
-// #define MANUAL_BED_LEVELING  // Add display menu option for bed leveling
-// #define MESH_BED_LEVELING    // Enable mesh bed leveling
+// #define MANUAL_BED_LEVELING  // Add display menu option for bed leveling.
+// #define MESH_BED_LEVELING    // Enable mesh bed leveling.
 
 #if ENABLED(MANUAL_BED_LEVELING)
-  #define MBL_Z_STEP 0.025  // Step size while manually probing Z axis
+  #define MBL_Z_STEP 0.025  // Step size while manually probing Z axis.
 #endif  // MANUAL_BED_LEVELING
 
 #if ENABLED(MESH_BED_LEVELING)
   #define MESH_MAX_X (X_MAX_POS - MESH_MIN_X)
   #define MESH_MIN_Y 10
   #define MESH_MAX_Y (Y_MAX_POS - MESH_MIN_Y)
-  #define MESH_NUM_X_POINTS 3  // Don't use more than 7 points per axis, implementation limited
+  #define MESH_NUM_X_POINTS 3  // Don't use more than 7 points per axis, implementation limited.
   #define MESH_NUM_Y_POINTS 3
-  #define MESH_HOME_SEARCH_Z 4  // Z after Home, bed somewhere below but above 0.0
+  #define MESH_HOME_SEARCH_Z 4  // Z after Home, bed somewhere below but above 0.0.
 #endif  // MESH_BED_LEVELING
 
 //===========================================================================
 
 // @section bedlevel
 
-#define ENABLE_AUTO_BED_LEVELING // Delete the comment to enable (remove // at the start of the line)
-//#define Z_MIN_PROBE_REPEATABILITY_TEST  // If not commented out, Z-Probe Repeatability test will be included if Auto Bed Leveling is Enabled.
+#define ENABLE_AUTO_BED_LEVELING // Delete the comment to enable (remove // at the start of the line).
+//#define Z_MIN_PROBE_REPEATABILITY_TEST  // If not commented out, Z probe repeatability test will be included if auto bed leveling is enabled.
 
 #if ENABLED(ENABLE_AUTO_BED_LEVELING)
 
-  // There are 2 different ways to specify probing locations
+  // There are 2 different ways to specify probing locations:
   //
   // - "grid" mode
   //   Probe several points in a rectangular grid.
   //   Probe 3 arbitrary points on the bed (that aren't colinear)
   //   You specify the XY coordinates of all 3 points.
 
-  // Enable this to sample the bed in a grid (least squares solution)
-  // Note: this feature generates 10KB extra code size
-  #define AUTO_BED_LEVELING_GRID  // Deltas only support grid mode
+  // Enable this to sample the bed in a grid (least squares solution).
+  // Note: this feature generates 10KB extra code size.
+  #define AUTO_BED_LEVELING_GRID  // Deltas only support grid mode.
 
   #if ENABLED(AUTO_BED_LEVELING_GRID)
 
     #define FRONT_PROBE_BED_POSITION -DELTA_PROBABLE_RADIUS
     #define BACK_PROBE_BED_POSITION DELTA_PROBABLE_RADIUS
 
-    #define MIN_PROBE_EDGE 10 // The probe square sides can be no smaller than this
+    #define MIN_PROBE_EDGE 10 // The Z probe square sides can be no smaller than this.
 
     // Non-linear bed leveling will be used.
     // Compensate by interpolating between the nearest four Z probe values for each point.
 
   #else  // !AUTO_BED_LEVELING_GRID
 
-      // Arbitrary points to probe. A simple cross-product
-      // is used to estimate the plane of the bed.
+      // Arbitrary points to probe.
+      // A simple cross-product is used to estimate the plane of the bed.
       #define ABL_PROBE_PT_1_X 15
       #define ABL_PROBE_PT_1_Y 180
       #define ABL_PROBE_PT_2_X 15
 
   #endif // AUTO_BED_LEVELING_GRID
 
-  // Offsets to the probe relative to the extruder tip (Hotend - Probe)
-  // X and Y offsets must be integers
+  // Offsets to the Z probe relative to the nozzle tip.
+  // X and Y offsets must be integers.
   #define X_PROBE_OFFSET_FROM_EXTRUDER -23 // KosselPro actual: -22.919
   #define Y_PROBE_OFFSET_FROM_EXTRUDER -6  // KosselPro actual: -6.304
   // Kossel Pro note: The correct value is likely -17.45 but I'd rather err on the side of
   // not giving someone a head crash. Use something like G29 Z-0.2 to adjust as needed.
   #define Z_PROBE_OFFSET_FROM_EXTRUDER -17.25  // Increase this if the first layer is too thin (remember: it's a negative number so increase means closer to zero).
 
-  #define Z_RAISE_BEFORE_HOMING 4       // (in mm) Raise Z before homing (G28) for Probe Clearance.
-                                        // Be sure you have this distance over your Z_MAX_POS in case
+  #define Z_RAISE_BEFORE_HOMING 4       // (in mm) Raise Z axis before homing (G28) for Z probe clearance.
+                                        // Be sure you have this distance over your Z_MAX_POS in case.
 
-  #define XY_TRAVEL_SPEED 8000         // X and Y axis travel speed between probes, in mm/min
+  #define XY_TRAVEL_SPEED 8000         // X and Y axis travel speed between probes, in mm/min.
 
-  #define Z_RAISE_BEFORE_PROBING 100  //How much the extruder will be raised before traveling to the first probing point.
-  #define Z_RAISE_BETWEEN_PROBINGS 5  //How much the extruder will be raised when traveling from between next probing points
-  #define Z_RAISE_AFTER_PROBING 15    //How much the extruder will be raised after the last probing point.
+  #define Z_RAISE_BEFORE_PROBING 100  // How much the Z axis will be raised before traveling to the first probing point.
+  #define Z_RAISE_BETWEEN_PROBINGS 5  // How much the Z axis will be raised when traveling from between next probing points.
+  #define Z_RAISE_AFTER_PROBING 15    // How much the Z axis will be raised after the last probing point.
 
-//   #define Z_PROBE_END_SCRIPT "G1 Z10 F12000\nG1 X15 Y330\nG1 Z0.5\nG1 Z10" //These commands will be executed in the end of G29 routine.
-                                                                            //Useful to retract a deployable probe.
+//   #define Z_PROBE_END_SCRIPT "G1 Z10 F12000\nG1 X15 Y330\nG1 Z0.5\nG1 Z10" // These commands will be executed in the end of G29 routine.
+                                                                            // Useful to retract a deployable Z probe.
 
-  //#define Z_PROBE_SLED // turn on if you have a z-probe mounted on a sled like those designed by Charles Bell
-  //#define SLED_DOCKING_OFFSET 5 // the extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
+  //#define Z_PROBE_SLED // Turn on if you have a Z probe mounted on a sled like those designed by Charles Bell.
+  //#define SLED_DOCKING_OFFSET 5 // The extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
 
   // Allen key retractable z-probe as seen on many Kossel delta printers - http://reprap.org/wiki/Kossel#Automatic_bed_leveling_probe
   // Deploys by touching z-axis belt. Retracts by pushing the probe down. Uses Z_MIN_PIN.
     #define Z_PROBE_ALLEN_KEY_STOW_3_FEEDRATE HOMING_FEEDRATE_Z
   #endif
 
-//If you have enabled the Bed Auto Leveling and are using the same Z Probe for Z Homing,
-//it is highly recommended you let this Z_SAFE_HOMING enabled!!!
+// If you have enabled the bed auto leveling and are using the same Z probe for Z homing,
+// it is highly recommended you let this Z_SAFE_HOMING enabled!!!
 
-  #define Z_SAFE_HOMING   // This feature is meant to avoid Z homing with probe outside the bed area.
+  #define Z_SAFE_HOMING   // This feature is meant to avoid Z homing with Z probe outside the bed area.
                           // When defined, it will:
-                          // - Allow Z homing only after X and Y homing AND stepper drivers still enabled
-                          // - If stepper drivers timeout, it will need X and Y homing again before Z homing
-                          // - Position the probe in a defined XY point before Z Homing when homing all axis (G28)
-                          // - Block Z homing only when the probe is outside bed area.
+                          // - Allow Z homing only after X and Y homing AND stepper drivers still enabled.
+                          // - If stepper drivers timeout, it will need X and Y homing again before Z homing.
+                          // - Position the Z probe in a defined XY point before Z Homing when homing all axis (G28).
+                          // - Block Z homing only when the Z probe is outside bed area.
 
   #if ENABLED(Z_SAFE_HOMING)
 
-    #define Z_SAFE_HOMING_X_POINT ((X_MIN_POS + X_MAX_POS) / 2)    // X point for Z homing when homing all axis (G28)
-    #define Z_SAFE_HOMING_Y_POINT ((Y_MIN_POS + Y_MAX_POS) / 2)    // Y point for Z homing when homing all axis (G28)
+    #define Z_SAFE_HOMING_X_POINT ((X_MIN_POS + X_MAX_POS) / 2)    // X point for Z homing when homing all axis (G28).
+    #define Z_SAFE_HOMING_Y_POINT ((Y_MIN_POS + Y_MAX_POS) / 2)    // Y point for Z homing when homing all axis (G28).
 
   #endif
 
-  // Support for a dedicated Z PROBE endstop separate from the Z MIN endstop.
-  // If you would like to use both a Z PROBE and a Z MIN endstop together , uncomment #define Z_MIN_PROBE_ENDSTOP and read the instructions below.
-  // If you want to still use the Z min endstop for homing, disable Z_SAFE_HOMING above. Eg; to park the head outside the bed area when homing with G28.
-  // WARNING: The Z MIN endstop will need to set properly as it would without a Z PROBE to prevent head crashes and premature stopping during a print.
-  // To use a separate Z PROBE endstop, you must have a Z_MIN_PROBE_PIN defined in the pins.h file for your control board.
-  // If you are using a servo based Z PROBE, you will need to enable NUM_SERVOS, Z_ENDSTOP_SERVO_NR and SERVO_ENDSTOP_ANGLES in the R/C Servo below.
-  // RAMPS 1.3/1.4 boards may be able to use the 5V, Ground and the D32 pin in the Aux 4 section of the RAMPS board. Use 5V for powered sensors, otherwise connect to ground and D32
-  // for normally closed configuration and 5V and D32 for normally open configurations. Normally closed configuration is advised and assumed.
-  // The D32 pin in Aux 4 on RAMPS maps to the Arduino D32 pin. Z_MIN_PROBE_PIN is setting the pin to use on the Arduino. Since the D32 pin on the RAMPS maps to D32 on Arduino, this works.
-  // D32 is currently selected in the RAMPS 1.3/1.4 pin file. All other boards will need changes to the respective pins_XXXXX.h file.
-  // WARNING: Setting the wrong pin may have unexpected and potentially disastrous outcomes. Use with caution and do your homework.
-
+  // Support for a dedicated Z probe endstop separate from the Z min endstop.
+  // If you would like to use both a Z probe and a Z min endstop together,
+  // uncomment #define Z_MIN_PROBE_ENDSTOP and read the instructions below.
+  // If you still want to use the Z min endstop for homing, disable Z_SAFE_HOMING above.
+  // Example: To park the head outside the bed area when homing with G28.
+  //
+  // WARNING:
+  // The Z min endstop will need to set properly as it would without a Z probe
+  // to prevent head crashes and premature stopping during a print.
+  //
+  // To use a separate Z probe endstop, you must have a Z_MIN_PROBE_PIN
+  // defined in the pins_XXXXX.h file for your control board.
+  // If you are using a servo based Z probe, you will need to enable NUM_SERVOS,
+  // Z_ENDSTOP_SERVO_NR and SERVO_ENDSTOP_ANGLES in the R/C SERVO support below.
+  // RAMPS 1.3/1.4 boards may be able to use the 5V, Ground and the D32 pin
+  // in the Aux 4 section of the RAMPS board. Use 5V for powered sensors,
+  // otherwise connect to ground and D32 for normally closed configuration
+  // and 5V and D32 for normally open configurations.
+  // Normally closed configuration is advised and assumed.
+  // The D32 pin in Aux 4 on RAMPS maps to the Arduino D32 pin.
+  // Z_MIN_PROBE_PIN is setting the pin to use on the Arduino.
+  // Since the D32 pin on the RAMPS maps to D32 on Arduino, this works.
+  // D32 is currently selected in the RAMPS 1.3/1.4 pin file.
+  // All other boards will need changes to the respective pins_XXXXX.h file.
+  //
+  // WARNING:
+  // Setting the wrong pin may have unexpected and potentially disastrous outcomes.
+  // Use with caution and do your homework.
+  //
   //#define Z_MIN_PROBE_ENDSTOP
 
 #endif // ENABLE_AUTO_BED_LEVELING
   #define EEPROM_CHITCHAT // Please keep turned on if you can.
 #endif
 
+//
+// M100 Free Memory Watcher
+//
+//#define M100_FREE_MEMORY_WATCHER // uncomment to add the M100 Free Memory Watcher for debug purpose
+
 // @section temperature
 
 // Preheat Constants
 // Servo Endstops
 //
 // This allows for servo actuated endstops, primary usage is for the Z Axis to eliminate calibration or bed height changes.
-// Use M851 to set the z-probe vertical offset from the nozzle. Store that setting with M500.
+// Use M851 to set the Z probe vertical offset from the nozzle. Store that setting with M500.
 //
 //#define X_ENDSTOP_SERVO_NR 1
 //#define Y_ENDSTOP_SERVO_NR 2

Marlin/example_configurations/makibox/Configuration.h

 //#define DISABLE_MAX_ENDSTOPS
 //#define DISABLE_MIN_ENDSTOPS
 
-// If you want to enable the Z Probe pin, but disable its use, uncomment the line below.
-// This only affects a Z Probe Endstop if you have separate Z min endstop as well and have
-// activated Z_MIN_PROBE_ENDSTOP below. If you are using the Z Min endstop on your Z Probe,
+// If you want to enable the Z probe pin, but disable its use, uncomment the line below.
+// This only affects a Z probe endstop if you have separate Z min endstop as well and have
+// activated Z_MIN_PROBE_ENDSTOP below. If you are using the Z Min endstop on your Z probe,
 // this has no effect.
 //#define DISABLE_Z_MIN_PROBE_ENDSTOP
 
 //=========================== Manual Bed Leveling ===========================
 //===========================================================================
 
-// #define MANUAL_BED_LEVELING  // Add display menu option for bed leveling
-// #define MESH_BED_LEVELING    // Enable mesh bed leveling
+// #define MANUAL_BED_LEVELING  // Add display menu option for bed leveling.
+// #define MESH_BED_LEVELING    // Enable mesh bed leveling.
 
 #if ENABLED(MANUAL_BED_LEVELING)
-  #define MBL_Z_STEP 0.025  // Step size while manually probing Z axis
+  #define MBL_Z_STEP 0.025  // Step size while manually probing Z axis.
 #endif  // MANUAL_BED_LEVELING
 
 #if ENABLED(MESH_BED_LEVELING)
   #define MESH_MAX_X (X_MAX_POS - MESH_MIN_X)
   #define MESH_MIN_Y 10
   #define MESH_MAX_Y (Y_MAX_POS - MESH_MIN_Y)
-  #define MESH_NUM_X_POINTS 3  // Don't use more than 7 points per axis, implementation limited
+  #define MESH_NUM_X_POINTS 3  // Don't use more than 7 points per axis, implementation limited.
   #define MESH_NUM_Y_POINTS 3
-  #define MESH_HOME_SEARCH_Z 4  // Z after Home, bed somewhere below but above 0.0
+  #define MESH_HOME_SEARCH_Z 4  // Z after Home, bed somewhere below but above 0.0.
 #endif  // MESH_BED_LEVELING
 
 //===========================================================================
 
 // @section bedlevel
 
-//#define ENABLE_AUTO_BED_LEVELING // Delete the comment to enable (remove // at the start of the line)
-#define Z_MIN_PROBE_REPEATABILITY_TEST  // If not commented out, Z-Probe Repeatability test will be included if Auto Bed Leveling is Enabled.
+//#define ENABLE_AUTO_BED_LEVELING // Delete the comment to enable (remove // at the start of the line).
+#define Z_MIN_PROBE_REPEATABILITY_TEST  // If not commented out, Z probe repeatability test will be included if auto bed leveling is enabled.
 
 #if ENABLED(ENABLE_AUTO_BED_LEVELING)
 
-  // There are 2 different ways to specify probing locations
+  // There are 2 different ways to specify probing locations:
   //
   // - "grid" mode
   //   Probe several points in a rectangular grid.
   //   Probe 3 arbitrary points on the bed (that aren't colinear)
   //   You specify the XY coordinates of all 3 points.
 
-  // Enable this to sample the bed in a grid (least squares solution)
-  // Note: this feature generates 10KB extra code size
+  // Enable this to sample the bed in a grid (least squares solution).
+  // Note: this feature generates 10KB extra code size.
   #define AUTO_BED_LEVELING_GRID
 
   #if ENABLED(AUTO_BED_LEVELING_GRID)
     #define FRONT_PROBE_BED_POSITION 20
     #define BACK_PROBE_BED_POSITION 170
 
-    #define MIN_PROBE_EDGE 10 // The probe square sides can be no smaller than this
+    #define MIN_PROBE_EDGE 10 // The Z probe square sides can be no smaller than this.
 
-    // Set the number of grid points per dimension
-    // You probably don't need more than 3 (squared=9)
+    // Set the number of grid points per dimension.
+    // You probably don't need more than 3 (squared=9).
     #define AUTO_BED_LEVELING_GRID_POINTS 2
 
   #else  // !AUTO_BED_LEVELING_GRID
 
-      // Arbitrary points to probe. A simple cross-product
-      // is used to estimate the plane of the bed.
+      // Arbitrary points to probe.
+      // A simple cross-product is used to estimate the plane of the bed.
       #define ABL_PROBE_PT_1_X 15
       #define ABL_PROBE_PT_1_Y 180
       #define ABL_PROBE_PT_2_X 15
 
   #endif // AUTO_BED_LEVELING_GRID
 
-  // Offsets to the probe relative to the extruder tip (Hotend - Probe)
-  // X and Y offsets must be integers
-  #define X_PROBE_OFFSET_FROM_EXTRUDER -25     // Probe on: -left  +right
-  #define Y_PROBE_OFFSET_FROM_EXTRUDER -29     // Probe on: -front +behind
-  #define Z_PROBE_OFFSET_FROM_EXTRUDER -12.35  // -below (always!)
+  // Offsets to the Z probe relative to the nozzle tip.
+  // X and Y offsets must be integers.
+  #define X_PROBE_OFFSET_FROM_EXTRUDER -25     // Z probe to nozzle X offset: -left  +right
+  #define Y_PROBE_OFFSET_FROM_EXTRUDER -29     // Z probe to nozzle Y offset: -front +behind
+  #define Z_PROBE_OFFSET_FROM_EXTRUDER -12.35  // Z probe to nozzle Z offset: -below (always!)
 
-  #define Z_RAISE_BEFORE_HOMING 4       // (in mm) Raise Z before homing (G28) for Probe Clearance.
-                                        // Be sure you have this distance over your Z_MAX_POS in case
+  #define Z_RAISE_BEFORE_HOMING 4       // (in mm) Raise Z axis before homing (G28) for Z probe clearance.
+                                        // Be sure you have this distance over your Z_MAX_POS in case.
 
-  #define XY_TRAVEL_SPEED 8000         // X and Y axis travel speed between probes, in mm/min
+  #define XY_TRAVEL_SPEED 8000         // X and Y axis travel speed between probes, in mm/min.
 
-  #define Z_RAISE_BEFORE_PROBING 15   //How much the extruder will be raised before traveling to the first probing point.
-  #define Z_RAISE_BETWEEN_PROBINGS 5  //How much the extruder will be raised when traveling from between next probing points
-  #define Z_RAISE_AFTER_PROBING 15    //How much the extruder will be raised after the last probing point.
+  #define Z_RAISE_BEFORE_PROBING 15   // How much the Z axis will be raised before traveling to the first probing point.
+  #define Z_RAISE_BETWEEN_PROBINGS 5  // How much the Z axis will be raised when traveling from between next probing points.
+  #define Z_RAISE_AFTER_PROBING 15    // How much the Z axis will be raised after the last probing point.
 
-//   #define Z_PROBE_END_SCRIPT "G1 Z10 F12000\nG1 X15 Y330\nG1 Z0.5\nG1 Z10" //These commands will be executed in the end of G29 routine.
-                                                                            //Useful to retract a deployable probe.
+//   #define Z_PROBE_END_SCRIPT "G1 Z10 F12000\nG1 X15 Y330\nG1 Z0.5\nG1 Z10" // These commands will be executed in the end of G29 routine.
+                                                                            // Useful to retract a deployable Z probe.
 
-  //#define Z_PROBE_SLED // turn on if you have a z-probe mounted on a sled like those designed by Charles Bell
-  //#define SLED_DOCKING_OFFSET 5 // the extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
+  //#define Z_PROBE_SLED // Turn on if you have a Z probe mounted on a sled like those designed by Charles Bell.
+  //#define SLED_DOCKING_OFFSET 5 // The extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
 
-//If you have enabled the Bed Auto Leveling and are using the same Z Probe for Z Homing,
-//it is highly recommended you let this Z_SAFE_HOMING enabled!!!
+// If you have enabled the bed auto leveling and are using the same Z probe for Z homing,
+// it is highly recommended you let this Z_SAFE_HOMING enabled!!!
 
-  #define Z_SAFE_HOMING   // This feature is meant to avoid Z homing with probe outside the bed area.
+  #define Z_SAFE_HOMING   // This feature is meant to avoid Z homing with Z probe outside the bed area.
                           // When defined, it will:
-                          // - Allow Z homing only after X and Y homing AND stepper drivers still enabled
-                          // - If stepper drivers timeout, it will need X and Y homing again before Z homing
-                          // - Position the probe in a defined XY point before Z Homing when homing all axis (G28)
-                          // - Block Z homing only when the probe is outside bed area.
+                          // - Allow Z homing only after X and Y homing AND stepper drivers still enabled.
+                          // - If stepper drivers timeout, it will need X and Y homing again before Z homing.
+                          // - Position the Z probe in a defined XY point before Z Homing when homing all axis (G28).
+                          // - Block Z homing only when the Z probe is outside bed area.
 
   #if ENABLED(Z_SAFE_HOMING)
 
-    #define Z_SAFE_HOMING_X_POINT ((X_MIN_POS + X_MAX_POS) / 2)    // X point for Z homing when homing all axis (G28)
-    #define Z_SAFE_HOMING_Y_POINT ((Y_MIN_POS + Y_MAX_POS) / 2)    // Y point for Z homing when homing all axis (G28)
+    #define Z_SAFE_HOMING_X_POINT ((X_MIN_POS + X_MAX_POS) / 2)    // X point for Z homing when homing all axis (G28).
+    #define Z_SAFE_HOMING_Y_POINT ((Y_MIN_POS + Y_MAX_POS) / 2)    // Y point for Z homing when homing all axis (G28).
 
   #endif
 
-  // Support for a dedicated Z PROBE endstop separate from the Z MIN endstop.
-  // If you would like to use both a Z PROBE and a Z MIN endstop together , uncomment #define Z_MIN_PROBE_ENDSTOP and read the instructions below.
-  // If you want to still use the Z min endstop for homing, disable Z_SAFE_HOMING above. Eg; to park the head outside the bed area when homing with G28.
-  // WARNING: The Z MIN endstop will need to set properly as it would without a Z PROBE to prevent head crashes and premature stopping during a print.
-  // To use a separate Z PROBE endstop, you must have a Z_MIN_PROBE_PIN defined in the pins.h file for your control board.
-  // If you are using a servo based Z PROBE, you will need to enable NUM_SERVOS, Z_ENDSTOP_SERVO_NR and SERVO_ENDSTOP_ANGLES in the R/C Servo below.
-  // RAMPS 1.3/1.4 boards may be able to use the 5V, Ground and the D32 pin in the Aux 4 section of the RAMPS board. Use 5V for powered sensors, otherwise connect to ground and D32
-  // for normally closed configuration and 5V and D32 for normally open configurations. Normally closed configuration is advised and assumed.
-  // The D32 pin in Aux 4 on RAMPS maps to the Arduino D32 pin. Z_MIN_PROBE_PIN is setting the pin to use on the Arduino. Since the D32 pin on the RAMPS maps to D32 on Arduino, this works.
-  // D32 is currently selected in the RAMPS 1.3/1.4 pin file. All other boards will need changes to the respective pins_XXXXX.h file.
-  // WARNING: Setting the wrong pin may have unexpected and potentially disastrous outcomes. Use with caution and do your homework.
-
+  // Support for a dedicated Z probe endstop separate from the Z min endstop.
+  // If you would like to use both a Z probe and a Z min endstop together,
+  // uncomment #define Z_MIN_PROBE_ENDSTOP and read the instructions below.
+  // If you still want to use the Z min endstop for homing, disable Z_SAFE_HOMING above.
+  // Example: To park the head outside the bed area when homing with G28.
+  //
+  // WARNING:
+  // The Z min endstop will need to set properly as it would without a Z probe
+  // to prevent head crashes and premature stopping during a print.
+  //
+  // To use a separate Z probe endstop, you must have a Z_MIN_PROBE_PIN
+  // defined in the pins_XXXXX.h file for your control board.
+  // If you are using a servo based Z probe, you will need to enable NUM_SERVOS,
+  // Z_ENDSTOP_SERVO_NR and SERVO_ENDSTOP_ANGLES in the R/C SERVO support below.
+  // RAMPS 1.3/1.4 boards may be able to use the 5V, Ground and the D32 pin
+  // in the Aux 4 section of the RAMPS board. Use 5V for powered sensors,
+  // otherwise connect to ground and D32 for normally closed configuration
+  // and 5V and D32 for normally open configurations.
+  // Normally closed configuration is advised and assumed.
+  // The D32 pin in Aux 4 on RAMPS maps to the Arduino D32 pin.
+  // Z_MIN_PROBE_PIN is setting the pin to use on the Arduino.
+  // Since the D32 pin on the RAMPS maps to D32 on Arduino, this works.
+  // D32 is currently selected in the RAMPS 1.3/1.4 pin file.
+  // All other boards will need changes to the respective pins_XXXXX.h file.
+  //
+  // WARNING:
+  // Setting the wrong pin may have unexpected and potentially disastrous outcomes.
+  // Use with caution and do your homework.
+  //
   //#define Z_MIN_PROBE_ENDSTOP
 
 #endif // ENABLE_AUTO_BED_LEVELING
   #define EEPROM_CHITCHAT // Please keep turned on if you can.
 #endif
 
+//
+// M100 Free Memory Watcher
+//
+//#define M100_FREE_MEMORY_WATCHER // uncomment to add the M100 Free Memory Watcher for debug purpose
+
 // @section temperature
 
 // Preheat Constants
 // Servo Endstops
 //
 // This allows for servo actuated endstops, primary usage is for the Z Axis to eliminate calibration or bed height changes.
-// Use M851 to set the z-probe vertical offset from the nozzle. Store that setting with M500.
+// Use M851 to set the Z probe vertical offset from the nozzle. Store that setting with M500.
 //
 //#define X_ENDSTOP_SERVO_NR 1
 //#define Y_ENDSTOP_SERVO_NR 2

Marlin/example_configurations/tvrrug/Round2/Configuration.h

 //#define DISABLE_MAX_ENDSTOPS
 //#define DISABLE_MIN_ENDSTOPS
 
-// If you want to enable the Z Probe pin, but disable its use, uncomment the line below.
-// This only affects a Z Probe Endstop if you have separate Z min endstop as well and have
-// activated Z_MIN_PROBE_ENDSTOP below. If you are using the Z Min endstop on your Z Probe,
+// If you want to enable the Z probe pin, but disable its use, uncomment the line below.
+// This only affects a Z probe endstop if you have separate Z min endstop as well and have
+// activated Z_MIN_PROBE_ENDSTOP below. If you are using the Z Min endstop on your Z probe,
 // this has no effect.
 //#define DISABLE_Z_MIN_PROBE_ENDSTOP
 
 //=========================== Manual Bed Leveling ===========================
 //===========================================================================
 
-// #define MANUAL_BED_LEVELING  // Add display menu option for bed leveling
-// #define MESH_BED_LEVELING    // Enable mesh bed leveling
+// #define MANUAL_BED_LEVELING  // Add display menu option for bed leveling.
+// #define MESH_BED_LEVELING    // Enable mesh bed leveling.
 
 #if ENABLED(MANUAL_BED_LEVELING)
-  #define MBL_Z_STEP 0.025  // Step size while manually probing Z axis
+  #define MBL_Z_STEP 0.025  // Step size while manually probing Z axis.
 #endif  // MANUAL_BED_LEVELING
 
 #if ENABLED(MESH_BED_LEVELING)
   #define MESH_MAX_X (X_MAX_POS - MESH_MIN_X)
   #define MESH_MIN_Y 10
   #define MESH_MAX_Y (Y_MAX_POS - MESH_MIN_Y)
-  #define MESH_NUM_X_POINTS 3  // Don't use more than 7 points per axis, implementation limited
+  #define MESH_NUM_X_POINTS 3  // Don't use more than 7 points per axis, implementation limited.
   #define MESH_NUM_Y_POINTS 3
-  #define MESH_HOME_SEARCH_Z 4  // Z after Home, bed somewhere below but above 0.0
+  #define MESH_HOME_SEARCH_Z 4  // Z after Home, bed somewhere below but above 0.0.
 #endif  // MESH_BED_LEVELING
 
 //===========================================================================
 
 // @section bedlevel
 
-//#define ENABLE_AUTO_BED_LEVELING // Delete the comment to enable (remove // at the start of the line)
-#define Z_MIN_PROBE_REPEATABILITY_TEST  // If not commented out, Z-Probe Repeatability test will be included if Auto Bed Leveling is Enabled.
+//#define ENABLE_AUTO_BED_LEVELING // Delete the comment to enable (remove // at the start of the line).
+#define Z_MIN_PROBE_REPEATABILITY_TEST  // If not commented out, Z probe repeatability test will be included if auto bed leveling is enabled.
 
 #if ENABLED(ENABLE_AUTO_BED_LEVELING)
 
-  // There are 2 different ways to specify probing locations
+  // There are 2 different ways to specify probing locations:
   //
   // - "grid" mode
   //   Probe several points in a rectangular grid.
   //   Probe 3 arbitrary points on the bed (that aren't colinear)
   //   You specify the XY coordinates of all 3 points.
 
-  // Enable this to sample the bed in a grid (least squares solution)
-  // Note: this feature generates 10KB extra code size
+  // Enable this to sample the bed in a grid (least squares solution).
+  // Note: this feature generates 10KB extra code size.
   #define AUTO_BED_LEVELING_GRID
 
   #if ENABLED(AUTO_BED_LEVELING_GRID)
     #define FRONT_PROBE_BED_POSITION 20
     #define BACK_PROBE_BED_POSITION 170
 
-    #define MIN_PROBE_EDGE 10 // The probe square sides can be no smaller than this
+    #define MIN_PROBE_EDGE 10 // The Z probe square sides can be no smaller than this.
 
-    // Set the number of grid points per dimension
-    // You probably don't need more than 3 (squared=9)
+    // Set the number of grid points per dimension.
+    // You probably don't need more than 3 (squared=9).
     #define AUTO_BED_LEVELING_GRID_POINTS 2
 
   #else  // !AUTO_BED_LEVELING_GRID
 
-      // Arbitrary points to probe. A simple cross-product
-      // is used to estimate the plane of the bed.
+      // Arbitrary points to probe.
+      // A simple cross-product is used to estimate the plane of the bed.
       #define ABL_PROBE_PT_1_X 15
       #define ABL_PROBE_PT_1_Y 180
       #define ABL_PROBE_PT_2_X 15
 
   #endif // AUTO_BED_LEVELING_GRID
 
-  // Offsets to the probe relative to the extruder tip (Hotend - Probe)
-  // X and Y offsets must be integers
-  #define X_PROBE_OFFSET_FROM_EXTRUDER -25     // Probe on: -left  +right
-  #define Y_PROBE_OFFSET_FROM_EXTRUDER -29     // Probe on: -front +behind
-  #define Z_PROBE_OFFSET_FROM_EXTRUDER -12.35  // -below (always!)
+  // Offsets to the Z probe relative to the nozzle tip.
+  // X and Y offsets must be integers.
+  #define X_PROBE_OFFSET_FROM_EXTRUDER -25     // Z probe to nozzle X offset: -left  +right
+  #define Y_PROBE_OFFSET_FROM_EXTRUDER -29     // Z probe to nozzle Y offset: -front +behind
+  #define Z_PROBE_OFFSET_FROM_EXTRUDER -12.35  // Z probe to nozzle Z offset: -below (always!)
 
-  #define Z_RAISE_BEFORE_HOMING 4       // (in mm) Raise Z before homing (G28) for Probe Clearance.
-                                        // Be sure you have this distance over your Z_MAX_POS in case
+  #define Z_RAISE_BEFORE_HOMING 4       // (in mm) Raise Z axis before homing (G28) for Z probe clearance.
+                                        // Be sure you have this distance over your Z_MAX_POS in case.
 
-  #define XY_TRAVEL_SPEED 8000         // X and Y axis travel speed between probes, in mm/min
+  #define XY_TRAVEL_SPEED 8000         // X and Y axis travel speed between probes, in mm/min.
 
-  #define Z_RAISE_BEFORE_PROBING 15   //How much the extruder will be raised before traveling to the first probing point.
-  #define Z_RAISE_BETWEEN_PROBINGS 5  //How much the extruder will be raised when traveling from between next probing points
-  #define Z_RAISE_AFTER_PROBING 15    //How much the extruder will be raised after the last probing point.
+  #define Z_RAISE_BEFORE_PROBING 15   // How much the Z axis will be raised before traveling to the first probing point.
+  #define Z_RAISE_BETWEEN_PROBINGS 5  // How much the Z axis will be raised when traveling from between next probing points.
+  #define Z_RAISE_AFTER_PROBING 15    // How much the Z axis will be raised after the last probing point.
 
-//   #define Z_PROBE_END_SCRIPT "G1 Z10 F12000\nG1 X15 Y330\nG1 Z0.5\nG1 Z10" //These commands will be executed in the end of G29 routine.
-                                                                            //Useful to retract a deployable probe.
+//   #define Z_PROBE_END_SCRIPT "G1 Z10 F12000\nG1 X15 Y330\nG1 Z0.5\nG1 Z10" // These commands will be executed in the end of G29 routine.
+                                                                            // Useful to retract a deployable Z probe.
 
-  //#define Z_PROBE_SLED // turn on if you have a z-probe mounted on a sled like those designed by Charles Bell
-  //#define SLED_DOCKING_OFFSET 5 // the extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
+  //#define Z_PROBE_SLED // Turn on if you have a Z probe mounted on a sled like those designed by Charles Bell.
+  //#define SLED_DOCKING_OFFSET 5 // The extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
 
-//If you have enabled the Bed Auto Leveling and are using the same Z Probe for Z Homing,
-//it is highly recommended you let this Z_SAFE_HOMING enabled!!!
+// If you have enabled the bed auto leveling and are using the same Z probe for Z homing,
+// it is highly recommended you let this Z_SAFE_HOMING enabled!!!
 
-  #define Z_SAFE_HOMING   // This feature is meant to avoid Z homing with probe outside the bed area.
+  #define Z_SAFE_HOMING   // This feature is meant to avoid Z homing with Z probe outside the bed area.
                           // When defined, it will:
-                          // - Allow Z homing only after X and Y homing AND stepper drivers still enabled
-                          // - If stepper drivers timeout, it will need X and Y homing again before Z homing
-                          // - Position the probe in a defined XY point before Z Homing when homing all axis (G28)
-                          // - Block Z homing only when the probe is outside bed area.
+                          // - Allow Z homing only after X and Y homing AND stepper drivers still enabled.
+                          // - If stepper drivers timeout, it will need X and Y homing again before Z homing.
+                          // - Position the Z probe in a defined XY point before Z Homing when homing all axis (G28).
+                          // - Block Z homing only when the Z probe is outside bed area.
 
   #if ENABLED(Z_SAFE_HOMING)
 
-    #define Z_SAFE_HOMING_X_POINT ((X_MIN_POS + X_MAX_POS) / 2)    // X point for Z homing when homing all axis (G28)
-    #define Z_SAFE_HOMING_Y_POINT ((Y_MIN_POS + Y_MAX_POS) / 2)    // Y point for Z homing when homing all axis (G28)
+    #define Z_SAFE_HOMING_X_POINT ((X_MIN_POS + X_MAX_POS) / 2)    // X point for Z homing when homing all axis (G28).
+    #define Z_SAFE_HOMING_Y_POINT ((Y_MIN_POS + Y_MAX_POS) / 2)    // Y point for Z homing when homing all axis (G28).
 
   #endif
 
-  // Support for a dedicated Z PROBE endstop separate from the Z MIN endstop.
-  // If you would like to use both a Z PROBE and a Z MIN endstop together , uncomment #define Z_MIN_PROBE_ENDSTOP and read the instructions below.
-  // If you want to still use the Z min endstop for homing, disable Z_SAFE_HOMING above. Eg; to park the head outside the bed area when homing with G28.
-  // WARNING: The Z MIN endstop will need to set properly as it would without a Z PROBE to prevent head crashes and premature stopping during a print.
-  // To use a separate Z PROBE endstop, you must have a Z_MIN_PROBE_PIN defined in the pins.h file for your control board.
-  // If you are using a servo based Z PROBE, you will need to enable NUM_SERVOS, Z_ENDSTOP_SERVO_NR and SERVO_ENDSTOP_ANGLES in the R/C Servo below.
-  // RAMPS 1.3/1.4 boards may be able to use the 5V, Ground and the D32 pin in the Aux 4 section of the RAMPS board. Use 5V for powered sensors, otherwise connect to ground and D32
-  // for normally closed configuration and 5V and D32 for normally open configurations. Normally closed configuration is advised and assumed.
-  // The D32 pin in Aux 4 on RAMPS maps to the Arduino D32 pin. Z_MIN_PROBE_PIN is setting the pin to use on the Arduino. Since the D32 pin on the RAMPS maps to D32 on Arduino, this works.
-  // D32 is currently selected in the RAMPS 1.3/1.4 pin file. All other boards will need changes to the respective pins_XXXXX.h file.
-  // WARNING: Setting the wrong pin may have unexpected and potentially disastrous outcomes. Use with caution and do your homework.
-
+  // Support for a dedicated Z probe endstop separate from the Z min endstop.
+  // If you would like to use both a Z probe and a Z min endstop together,
+  // uncomment #define Z_MIN_PROBE_ENDSTOP and read the instructions below.
+  // If you still want to use the Z min endstop for homing, disable Z_SAFE_HOMING above.
+  // Example: To park the head outside the bed area when homing with G28.
+  //
+  // WARNING:
+  // The Z min endstop will need to set properly as it would without a Z probe
+  // to prevent head crashes and premature stopping during a print.
+  //
+  // To use a separate Z probe endstop, you must have a Z_MIN_PROBE_PIN
+  // defined in the pins_XXXXX.h file for your control board.
+  // If you are using a servo based Z probe, you will need to enable NUM_SERVOS,
+  // Z_ENDSTOP_SERVO_NR and SERVO_ENDSTOP_ANGLES in the R/C SERVO support below.
+  // RAMPS 1.3/1.4 boards may be able to use the 5V, Ground and the D32 pin
+  // in the Aux 4 section of the RAMPS board. Use 5V for powered sensors,
+  // otherwise connect to ground and D32 for normally closed configuration
+  // and 5V and D32 for normally open configurations.
+  // Normally closed configuration is advised and assumed.
+  // The D32 pin in Aux 4 on RAMPS maps to the Arduino D32 pin.
+  // Z_MIN_PROBE_PIN is setting the pin to use on the Arduino.
+  // Since the D32 pin on the RAMPS maps to D32 on Arduino, this works.
+  // D32 is currently selected in the RAMPS 1.3/1.4 pin file.
+  // All other boards will need changes to the respective pins_XXXXX.h file.
+  //
+  // WARNING:
+  // Setting the wrong pin may have unexpected and potentially disastrous outcomes.
+  // Use with caution and do your homework.
+  //
   //#define Z_MIN_PROBE_ENDSTOP
 
 #endif // ENABLE_AUTO_BED_LEVELING
   #define EEPROM_CHITCHAT // Please keep turned on if you can.
 #endif
 
+//
+// M100 Free Memory Watcher
+//
+//#define M100_FREE_MEMORY_WATCHER // uncomment to add the M100 Free Memory Watcher for debug purpose
+
 // @section temperature
 
 // Preheat Constants
 // Servo Endstops
 //
 // This allows for servo actuated endstops, primary usage is for the Z Axis to eliminate calibration or bed height changes.
-// Use M851 to set the z-probe vertical offset from the nozzle. Store that setting with M500.
+// Use M851 to set the Z probe vertical offset from the nozzle. Store that setting with M500.
 //
 //#define X_ENDSTOP_SERVO_NR 1
 //#define Y_ENDSTOP_SERVO_NR 2

Marlin/pins_BRAINWAVE_PRO.h

 #define Z_DIR_PIN          28
 #define Z_ENABLE_PIN       37
 #define Z_MAX_PIN          36
-#define Z_MIN_PIN          17  // Bed probe
+#define Z_MIN_PIN          17  // Bed Z probe
 
 #define E0_STEP_PIN        35
 #define E0_DIR_PIN         34