Add G38.4 and G38.5

Marlin/Configuration_adv.h

@@ -1068,11 +1068,17 @@
 // Support for G5 with XYZE destination and IJPQ offsets. Requires ~2666 bytes.
 //#define BEZIER_CURVE_SUPPORT
 
-// G38.2 and G38.3 Probe Target
-// Set MULTIPLE_PROBING if you want G38 to double touch
+/**
+ * G38 Probe Target
+ *
+ * This option adds G38.2 and G38.3 (probe towards target)
+ * and optionally G38.4 and G38.5 (probe away from target).
+ * Set MULTIPLE_PROBING for G38 to probe more than once.
+ */
 //#define G38_PROBE_TARGET
 #if ENABLED(G38_PROBE_TARGET)
-  #define G38_MINIMUM_MOVE 0.0275 // minimum distance in mm that will produce a move (determined using the print statement in check_move)
+  //#define G38_PROBE_AWAY        // Include G38.4 and G38.5 to probe away from target
+  #define G38_MINIMUM_MOVE 0.0275 // (mm) Minimum distance that will produce a move.
 #endif
 
 // Moves (or segments) with fewer steps than this will be joined with the next move

Marlin/src/Marlin.cpp

@@ -114,8 +114,8 @@
 #endif
 
 #if ENABLED(G38_PROBE_TARGET)
-  bool G38_move = false,
-       G38_endstop_hit = false;
+  uint8_t G38_move; // = 0
+  bool G38_did_trigger; // = false
 #endif
 
 #if ENABLED(DELTA)

Marlin/src/Marlin.h

@@ -309,8 +309,8 @@ void manage_inactivity(const bool ignore_stepper_queue=false);
 #endif
 
 #if ENABLED(G38_PROBE_TARGET)
-  extern bool G38_move,        // flag to tell the interrupt handler that a G38 command is being run
-              G38_endstop_hit; // flag from the interrupt handler to indicate if the endstop went active
+  extern uint8_t G38_move;          // Flag to tell the ISR that G38 is in progress, and the type
+  extern bool G38_did_trigger;      // Flag from the ISR to indicate the endstop changed
 #endif
 
 /**

Marlin/src/gcode/gcode.cpp

@@ -258,9 +258,14 @@ void GcodeSuite::process_parsed_command(
       #endif
 
       #if ENABLED(G38_PROBE_TARGET)
-        case 38:                                                  // G38.2 & G38.3: Probe towards target
-          if (parser.subcode == 2 || parser.subcode == 3)
-            G38(parser.subcode == 2);
+        case 38:                                                  // G38.2, G38.3: Probe towards target
+          if (WITHIN(parser.subcode, 2,
+            #if ENABLED(G38_PROBE_AWAY)
+              5
+            #else
+              3
+            #endif
+          )) G38(parser.subcode);                                 // G38.4, G38.5: Probe away from target
           break;
       #endif
 

Marlin/src/gcode/gcode.h

@@ -415,7 +415,7 @@ class GcodeSuite {
   #endif
 
   #if ENABLED(G38_PROBE_TARGET)
-    static void G38(const bool is_38_2);
+    static void G38(const int8_t subcode);
   #endif
 
   #if HAS_MESH

Marlin/src/gcode/probe/G38.cpp

@@ -31,7 +31,18 @@
 #include "../../module/stepper.h"
 #include "../../module/probe.h"
 
-static bool G38_run_probe() {
+inline void G38_single_probe(const uint8_t move_value) {
+  endstops.enable(true);
+  G38_move = move_value;
+  prepare_move_to_destination();
+  planner.synchronize();
+  G38_move = 0;
+  endstops.hit_on_purpose();
+  set_current_from_steppers_for_axis(ALL_AXES);
+  sync_plan_position();
+}
+
+inline bool G38_run_probe() {
 
   bool G38_pass_fail = false;
 
@@ -46,19 +57,19 @@ static bool G38_run_probe() {
 
   planner.synchronize();  // wait until the machine is idle
 
-  // Move until destination reached or target hit
-  endstops.enable(true);
-  G38_move = true;
-  G38_endstop_hit = false;
-  prepare_move_to_destination();
-  planner.synchronize();
-  G38_move = false;
+  // Move flag value
+  #if ENABLED(G38_PROBE_AWAY)
+    const uint8_t move_value = parser.subcode;
+  #else
+    constexpr uint8_t move_value = 1;
+  #endif
 
-  endstops.hit_on_purpose();
-  set_current_from_steppers_for_axis(ALL_AXES);
-  sync_plan_position();
+  G38_did_trigger = false;
 
-  if (G38_endstop_hit) {
+  // Move until destination reached or target hit
+  G38_single_probe(move_value);
+
+  if (G38_did_trigger) {
 
     G38_pass_fail = true;
 
@@ -70,45 +81,50 @@ static bool G38_run_probe() {
       prepare_move_to_destination();
       planner.synchronize();
 
-      feedrate_mm_s /= 4;
+      REMEMBER(fr, feedrate_mm_s, feedrate_mm_s * 0.25);
 
       // Bump the target more slowly
       LOOP_XYZ(i) destination[i] -= retract_mm[i] * 2;
 
-      endstops.enable(true);
-      G38_move = true;
-      prepare_move_to_destination();
-      planner.synchronize();
-      G38_move = false;
-
-      set_current_from_steppers_for_axis(ALL_AXES);
-      sync_plan_position();
+      G38_single_probe(move_value);
     #endif
   }
 
-  endstops.hit_on_purpose();
   endstops.not_homing();
   return G38_pass_fail;
 }
 
 /**
- * G38.2 - probe toward workpiece, stop on contact, signal error if failure
- * G38.3 - probe toward workpiece, stop on contact
+ * G38 Probe Target
+ *
+ *  G38.2 - Probe toward workpiece, stop on contact, signal error if failure
+ *  G38.3 - Probe toward workpiece, stop on contact
  *
- * Like G28 except uses Z min probe for all axes
+ * With G38_PROBE_AWAY:
+ *
+ *  G38.4 - Probe away from workpiece, stop on contact break, signal error if failure
+ *  G38.5 - Probe away from workpiece, stop on contact break
  */
-void GcodeSuite::G38(const bool is_38_2) {
+void GcodeSuite::G38(const int8_t subcode) {
   // Get X Y Z E F
   get_destination_from_command();
 
   setup_for_endstop_or_probe_move();
 
+  const bool error_on_fail =
+    #if ENABLED(G38_PROBE_AWAY)
+      !TEST(subcode, 0)
+    #else
+      (subcode == 2)
+    #endif
+  ;
+
   // If any axis has enough movement, do the move
   LOOP_XYZ(i)
     if (ABS(destination[i] - current_position[i]) >= G38_MINIMUM_MOVE) {
       if (!parser.seenval('F')) feedrate_mm_s = homing_feedrate((AxisEnum)i);
       // If G38.2 fails throw an error
-      if (!G38_run_probe() && is_38_2) SERIAL_ERROR_MSG("Failed to reach target");
+      if (!G38_run_probe() && error_on_fail) SERIAL_ERROR_MSG("Failed to reach target");
       break;
     }
 

Marlin/src/module/endstops.cpp

@@ -672,14 +672,17 @@ void Endstops::update() {
   }while(0)
 
   #if ENABLED(G38_PROBE_TARGET) && PIN_EXISTS(Z_MIN_PROBE) && !(CORE_IS_XY || CORE_IS_XZ)
+    #if ENABLED(G38_PROBE_AWAY)
+      #define _G38_OPEN_STATE (G38_move >= 4)
+    #else
+      #define _G38_OPEN_STATE LOW
+    #endif
     // If G38 command is active check Z_MIN_PROBE for ALL movement
-    if (G38_move) {
-      if (TEST_ENDSTOP(_ENDSTOP(Z, MIN_PROBE))) {
-        if      (stepper.axis_is_moving(X_AXIS)) { _ENDSTOP_HIT(X, MIN); planner.endstop_triggered(X_AXIS); }
-        else if (stepper.axis_is_moving(Y_AXIS)) { _ENDSTOP_HIT(Y, MIN); planner.endstop_triggered(Y_AXIS); }
-        else if (stepper.axis_is_moving(Z_AXIS)) { _ENDSTOP_HIT(Z, MIN); planner.endstop_triggered(Z_AXIS); }
-        G38_endstop_hit = true;
-      }
+    if (G38_move && TEST_ENDSTOP(_ENDSTOP(Z, MIN_PROBE)) != _G38_OPEN_STATE) {
+           if (stepper.axis_is_moving(X_AXIS)) { _ENDSTOP_HIT(X, MIN); planner.endstop_triggered(X_AXIS); }
+      else if (stepper.axis_is_moving(Y_AXIS)) { _ENDSTOP_HIT(Y, MIN); planner.endstop_triggered(Y_AXIS); }
+      else if (stepper.axis_is_moving(Z_AXIS)) { _ENDSTOP_HIT(Z, MIN); planner.endstop_triggered(Z_AXIS); }
+      G38_did_trigger = true;
     }
   #endif
 

config/default/Configuration_adv.h

@@ -1068,11 +1068,17 @@
 // Support for G5 with XYZE destination and IJPQ offsets. Requires ~2666 bytes.
 //#define BEZIER_CURVE_SUPPORT
 
-// G38.2 and G38.3 Probe Target
-// Set MULTIPLE_PROBING if you want G38 to double touch
+/**
+ * G38 Probe Target
+ *
+ * This option adds G38.2 and G38.3 (probe towards target)
+ * and optionally G38.4 and G38.5 (probe away from target).
+ * Set MULTIPLE_PROBING for G38 to probe more than once.
+ */
 //#define G38_PROBE_TARGET
 #if ENABLED(G38_PROBE_TARGET)
-  #define G38_MINIMUM_MOVE 0.0275 // minimum distance in mm that will produce a move (determined using the print statement in check_move)
+  //#define G38_PROBE_AWAY        // Include G38.4 and G38.5 to probe away from target
+  #define G38_MINIMUM_MOVE 0.0275 // (mm) Minimum distance that will produce a move.
 #endif
 
 // Moves (or segments) with fewer steps than this will be joined with the next move

config/examples/3DFabXYZ/Migbot/Configuration_adv.h

@@ -1068,11 +1068,17 @@
 // Support for G5 with XYZE destination and IJPQ offsets. Requires ~2666 bytes.
 //#define BEZIER_CURVE_SUPPORT
 
-// G38.2 and G38.3 Probe Target
-// Set MULTIPLE_PROBING if you want G38 to double touch
+/**
+ * G38 Probe Target
+ *
+ * This option adds G38.2 and G38.3 (probe towards target)
+ * and optionally G38.4 and G38.5 (probe away from target).
+ * Set MULTIPLE_PROBING for G38 to probe more than once.
+ */
 //#define G38_PROBE_TARGET
 #if ENABLED(G38_PROBE_TARGET)
-  #define G38_MINIMUM_MOVE 0.0275 // minimum distance in mm that will produce a move (determined using the print statement in check_move)
+  //#define G38_PROBE_AWAY        // Include G38.4 and G38.5 to probe away from target
+  #define G38_MINIMUM_MOVE 0.0275 // (mm) Minimum distance that will produce a move.
 #endif
 
 // Moves (or segments) with fewer steps than this will be joined with the next move

config/examples/AlephObjects/TAZ4/Configuration_adv.h

@@ -1068,11 +1068,17 @@
 // Support for G5 with XYZE destination and IJPQ offsets. Requires ~2666 bytes.
 //#define BEZIER_CURVE_SUPPORT
 
-// G38.2 and G38.3 Probe Target
-// Set MULTIPLE_PROBING if you want G38 to double touch
+/**
+ * G38 Probe Target
+ *
+ * This option adds G38.2 and G38.3 (probe towards target)
+ * and optionally G38.4 and G38.5 (probe away from target).
+ * Set MULTIPLE_PROBING for G38 to probe more than once.
+ */
 //#define G38_PROBE_TARGET
 #if ENABLED(G38_PROBE_TARGET)
-  #define G38_MINIMUM_MOVE 0.0275 // minimum distance in mm that will produce a move (determined using the print statement in check_move)
+  //#define G38_PROBE_AWAY        // Include G38.4 and G38.5 to probe away from target
+  #define G38_MINIMUM_MOVE 0.0275 // (mm) Minimum distance that will produce a move.
 #endif
 
 // Moves (or segments) with fewer steps than this will be joined with the next move

config/examples/AliExpress/UM2pExt/Configuration_adv.h

@@ -1068,11 +1068,17 @@
 // Support for G5 with XYZE destination and IJPQ offsets. Requires ~2666 bytes.
 //#define BEZIER_CURVE_SUPPORT
 
-// G38.2 and G38.3 Probe Target
-// Set MULTIPLE_PROBING if you want G38 to double touch
+/**
+ * G38 Probe Target
+ *
+ * This option adds G38.2 and G38.3 (probe towards target)
+ * and optionally G38.4 and G38.5 (probe away from target).
+ * Set MULTIPLE_PROBING for G38 to probe more than once.
+ */
 //#define G38_PROBE_TARGET
 #if ENABLED(G38_PROBE_TARGET)
-  #define G38_MINIMUM_MOVE 0.0275 // minimum distance in mm that will produce a move (determined using the print statement in check_move)
+  //#define G38_PROBE_AWAY        // Include G38.4 and G38.5 to probe away from target
+  #define G38_MINIMUM_MOVE 0.0275 // (mm) Minimum distance that will produce a move.
 #endif
 
 // Moves (or segments) with fewer steps than this will be joined with the next move

config/examples/Anet/A2/Configuration_adv.h

@@ -1068,11 +1068,17 @@
 // Support for G5 with XYZE destination and IJPQ offsets. Requires ~2666 bytes.
 //#define BEZIER_CURVE_SUPPORT
 
-// G38.2 and G38.3 Probe Target
-// Set MULTIPLE_PROBING if you want G38 to double touch
+/**
+ * G38 Probe Target
+ *
+ * This option adds G38.2 and G38.3 (probe towards target)
+ * and optionally G38.4 and G38.5 (probe away from target).
+ * Set MULTIPLE_PROBING for G38 to probe more than once.
+ */
 //#define G38_PROBE_TARGET
 #if ENABLED(G38_PROBE_TARGET)
-  #define G38_MINIMUM_MOVE 0.0275 // minimum distance in mm that will produce a move (determined using the print statement in check_move)
+  //#define G38_PROBE_AWAY        // Include G38.4 and G38.5 to probe away from target
+  #define G38_MINIMUM_MOVE 0.0275 // (mm) Minimum distance that will produce a move.
 #endif
 
 // Moves (or segments) with fewer steps than this will be joined with the next move

config/examples/Anet/A2plus/Configuration_adv.h

@@ -1068,11 +1068,17 @@
 // Support for G5 with XYZE destination and IJPQ offsets. Requires ~2666 bytes.
 //#define BEZIER_CURVE_SUPPORT
 
-// G38.2 and G38.3 Probe Target
-// Set MULTIPLE_PROBING if you want G38 to double touch
+/**
+ * G38 Probe Target
+ *
+ * This option adds G38.2 and G38.3 (probe towards target)
+ * and optionally G38.4 and G38.5 (probe away from target).
+ * Set MULTIPLE_PROBING for G38 to probe more than once.
+ */
 //#define G38_PROBE_TARGET
 #if ENABLED(G38_PROBE_TARGET)
-  #define G38_MINIMUM_MOVE 0.0275 // minimum distance in mm that will produce a move (determined using the print statement in check_move)
+  //#define G38_PROBE_AWAY        // Include G38.4 and G38.5 to probe away from target
+  #define G38_MINIMUM_MOVE 0.0275 // (mm) Minimum distance that will produce a move.
 #endif
 
 // Moves (or segments) with fewer steps than this will be joined with the next move

config/examples/Anet/A6/Configuration_adv.h

@@ -1067,11 +1067,17 @@
 // Support for G5 with XYZE destination and IJPQ offsets. Requires ~2666 bytes.
 //#define BEZIER_CURVE_SUPPORT
 
-// G38.2 and G38.3 Probe Target
-// Set MULTIPLE_PROBING if you want G38 to double touch
+/**
+ * G38 Probe Target
+ *
+ * This option adds G38.2 and G38.3 (probe towards target)
+ * and optionally G38.4 and G38.5 (probe away from target).
+ * Set MULTIPLE_PROBING for G38 to probe more than once.
+ */
 //#define G38_PROBE_TARGET
 #if ENABLED(G38_PROBE_TARGET)
-  #define G38_MINIMUM_MOVE 0.0275 // minimum distance in mm that will produce a move (determined using the print statement in check_move)
+  //#define G38_PROBE_AWAY        // Include G38.4 and G38.5 to probe away from target
+  #define G38_MINIMUM_MOVE 0.0275 // (mm) Minimum distance that will produce a move.
 #endif
 
 // Moves (or segments) with fewer steps than this will be joined with the next move

config/examples/Anet/A8/Configuration_adv.h

@@ -1068,11 +1068,17 @@
 // Support for G5 with XYZE destination and IJPQ offsets. Requires ~2666 bytes.
 //#define BEZIER_CURVE_SUPPORT
 
-// G38.2 and G38.3 Probe Target
-// Set MULTIPLE_PROBING if you want G38 to double touch
+/**
+ * G38 Probe Target
+ *
+ * This option adds G38.2 and G38.3 (probe towards target)
+ * and optionally G38.4 and G38.5 (probe away from target).
+ * Set MULTIPLE_PROBING for G38 to probe more than once.
+ */
 //#define G38_PROBE_TARGET
 #if ENABLED(G38_PROBE_TARGET)
-  #define G38_MINIMUM_MOVE 0.0275 // minimum distance in mm that will produce a move (determined using the print statement in check_move)
+  //#define G38_PROBE_AWAY        // Include G38.4 and G38.5 to probe away from target
+  #define G38_MINIMUM_MOVE 0.0275 // (mm) Minimum distance that will produce a move.
 #endif
 
 // Moves (or segments) with fewer steps than this will be joined with the next move