🐛 Fix FTM E value overflow; 🔧 FTM_DIR_CHANGE_HOLD_* (#28277)

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

Marlin/Configuration_adv.h

@@ -1238,6 +1238,25 @@
   #define FTM_FS                     1000   // (Hz) Frequency for trajectory generation.
   #define FTM_MIN_SHAPE_FREQ           20   // (Hz) Minimum shaping frequency, lower consumes more RAM
 
+  /**
+   * TMC2208 / TMC2208_STANDALONE drivers require a brief pause after a DIR change
+   * to prevent a standstill shutdown when using StealthChop (the standalone default).
+   * These options cause FT Motion to delay for > 750µs after a DIR change on a given axis.
+   * Disable only if you are certain that this can never happen with your TMC2208s.
+   */
+  #if AXIS_DRIVER_TYPE_X(TMC2208) || AXIS_DRIVER_TYPE_X(TMC2208_STANDALONE)
+    #define FTM_DIR_CHANGE_HOLD_X
+  #endif
+  #if AXIS_DRIVER_TYPE_Y(TMC2208) || AXIS_DRIVER_TYPE_Y(TMC2208_STANDALONE)
+    #define FTM_DIR_CHANGE_HOLD_Y
+  #endif
+  #if AXIS_DRIVER_TYPE_Z(TMC2208) || AXIS_DRIVER_TYPE_Z(TMC2208_STANDALONE)
+    #define FTM_DIR_CHANGE_HOLD_Z
+  #endif
+  #if HAS_E_DRIVER(TMC2208) || HAS_E_DRIVER(TMC2208_STANDALONE)
+    #define FTM_DIR_CHANGE_HOLD_E
+  #endif
+
 #endif // FT_MOTION
 
 /**

Marlin/src/inc/Conditionals-4-adv.h

@@ -360,30 +360,6 @@
     #define HAS_FTM_EI_SHAPING 1
   #endif
 
-  /**
-   * TMC2208 Direction-Flip Delay
-   *
-   * Some TMC2208 / TMC2208_STANDALONE drivers may require a short delay after a DIR change
-   * to prevent a standstill error, especially when using stealthChop (the standalone default).
-   *
-   * When enabled for an axis, FT Motion will hold that axis for > 750µs after a DIR change
-   * by holding its trajectory coordinate constant for a multiple of FTM_TS frames. For the
-   * default FTM_FS = 1000, it is a single 1ms frame.
-   *
-   * Other axes keep moving normally, and the wait is canceled if the axis flips again.
-   */
-  #if AXIS_DRIVER_TYPE_X(TMC2208) || AXIS_DRIVER_TYPE_X(TMC2208_STANDALONE)
-    #define FTM_DIR_CHANGE_HOLD_X 1
-  #endif
-  #if AXIS_DRIVER_TYPE_Y(TMC2208) || AXIS_DRIVER_TYPE_Y(TMC2208_STANDALONE)
-    #define FTM_DIR_CHANGE_HOLD_Y 1
-  #endif
-  #if AXIS_DRIVER_TYPE_Z(TMC2208) || AXIS_DRIVER_TYPE_Z(TMC2208_STANDALONE)
-    #define FTM_DIR_CHANGE_HOLD_Z 1
-  #endif
-  #if HAS_E_DRIVER(TMC2208) || HAS_E_DRIVER(TMC2208_STANDALONE)
-    #define FTM_DIR_CHANGE_HOLD_E 1
-  #endif
   #if ANY(FTM_DIR_CHANGE_HOLD_X, FTM_DIR_CHANGE_HOLD_Y, FTM_DIR_CHANGE_HOLD_Z, FTM_DIR_CHANGE_HOLD_E)
     #define HAS_FTM_DIR_CHANGE_HOLD 1
   #endif

Marlin/src/module/ft_motion.cpp

@@ -380,7 +380,7 @@ bool FTMotion::plan_next_block() {
       if (current_block->is_sync_pos()) stepper._set_position(current_block->position);
       continue;
     }
-    ensure_float_precision();
+    ensure_extruder_float_precision();
 
     #if ENABLED(POWER_LOSS_RECOVERY)
       recovery.info.sdpos = current_block->sdpos;
@@ -441,7 +441,7 @@ bool FTMotion::plan_next_block() {
    * resolution = 2^(floor(log2(|x|)) - 23)
    * By resetting at ±1'000mm (1 meter), we get a minimum resolution of ~ 0.00006mm, enough for smoothing to work well.
    */
-  void FTMotion::ensure_float_precision() {
+  void FTMotion::ensure_extruder_float_precision() {
     constexpr float FTM_POSITION_WRAP_THRESHOLD = 1000; // (mm) Reset when position exceeds this to prevent floating point precision loss
     if (ABS(endPos_prevBlock.E) < FTM_POSITION_WRAP_THRESHOLD) return;
 
@@ -462,6 +462,9 @@ bool FTMotion::plan_next_block() {
     // Offset linear advance previous position
     prev_traj_e += offset;
 
+    // Make sure the difference is accounted-for in the past
+    last_target_traj.e += offset;
+
     // Offset stepper current position
     const int64_t delta_steps_q48_16 = offset * planner.settings.axis_steps_per_mm[block_extruder_axis] * (1ULL << 16);
     stepping.curr_steps_q48_16.E += delta_steps_q48_16;

Marlin/src/module/ft_motion.h

@@ -403,7 +403,7 @@ class FTMotion {
     static void fill_stepper_plan_buffer();
     static xyze_float_t calc_traj_point(const float dist);
     static bool plan_next_block();
-    static void ensure_float_precision() IF_DISABLED(HAS_EXTRUDERS, {});
+    static void ensure_extruder_float_precision() IF_DISABLED(HAS_EXTRUDERS, {});
 
 }; // class FTMotion