✨ Instant Freeze/Resume Function (#17462)

Co-authored-by: Scott Lahteine <thinkyhead@users.noreply.github.com>

Marlin/src/module/stepper.cpp

@@ -179,6 +179,10 @@ bool Stepper::abort_current_block;
 uint32_t Stepper::acceleration_time, Stepper::deceleration_time;
 uint8_t Stepper::steps_per_isr;
 
+#if HAS_FREEZE_PIN
+  bool Stepper::frozen; // = false
+#endif
+
 IF_DISABLED(ADAPTIVE_STEP_SMOOTHING, constexpr) uint8_t Stepper::oversampling_factor;
 
 xyze_long_t Stepper::delta_error{0};
@@ -1531,6 +1535,9 @@ void Stepper::pulse_phase_isr() {
   // If there is no current block, do nothing
   if (!current_block) return;
 
+  // Skipping step processing causes motion to freeze
+  if (TERN0(HAS_FREEZE_PIN, frozen)) return;
+
   // Count of pending loops and events for this iteration
   const uint32_t pending_events = step_event_count - step_events_completed;
   uint8_t events_to_do = _MIN(pending_events, steps_per_isr);

Marlin/src/module/stepper.h

@@ -266,6 +266,10 @@ class Stepper {
       static constexpr uint8_t last_moved_extruder = 0;
     #endif
 
+    #if HAS_FREEZE_PIN
+      static bool frozen;                   // Set this flag to instantly freeze motion
+    #endif
+
   private:
 
     static block_t* current_block;          // A pointer to the block currently being traced