🐛 Minor Fixed-Time Motion patches

Marlin/src/MarlinCore.cpp

@@ -1624,6 +1624,11 @@ void setup() {
     SETUP_RUN(bdl.init(I2C_BD_SDA_PIN, I2C_BD_SCL_PIN, I2C_BD_DELAY));
   #endif
 
+
+  #if ENABLED(FT_MOTION)
+    SETUP_RUN(fxdTiCtrl.init());
+  #endif
+
   marlin_state = MF_RUNNING;
 
   #ifdef STARTUP_TUNE

Marlin/src/inc/SanityCheck.h

@@ -4030,6 +4030,13 @@ static_assert(_PLUS_TEST(4), "HOMING_FEEDRATE_MM_M values must be positive.");
   #endif
 #endif
 
+/**
+ * Fixed-Time Motion limitations
+ */
+#if ENABLED(FT_MOTION) && (NUM_AXES > 3 || E_STEPPERS > 1 || NUM_Z_STEPPERS > 1 || ANY(DUAL_X_CARRIAGE, HAS_DUAL_X_STEPPERS, HAS_DUAL_Y_STEPPERS, HAS_MULTI_EXTRUDER, MIXING_EXTRUDER))
+  #error "FT_MOTION is currently limited to machines with 3 linear axes and a single extruder."
+#endif
+
 // Multi-Stepping Limit
 static_assert(WITHIN(MULTISTEPPING_LIMIT, 1, 128) && IS_POWER_OF_2(MULTISTEPPING_LIMIT), "MULTISTEPPING_LIMIT must be 1, 2, 4, 8, 16, 32, 64, or 128.");
 

Marlin/src/module/ft_motion.cpp

@@ -211,9 +211,6 @@ void FxdTiCtrl::loop() {
 
   if (!cfg_mode) return;
 
-  static bool initd = false;
-  if (!initd) { init(); initd = true; }
-
   // Handle block abort with the following sequence:
   // 1. Zero out commands in stepper ISR.
   // 2. Drain the motion buffer, stop processing until they are emptied.

Marlin/src/module/stepper.cpp

@@ -3466,7 +3466,7 @@ void Stepper::report_positions() {
 
     #if HAS_Z_AXIS
       // Update step counts
-      if (z_step) count_position.z += z_dir ? -1 : 1;
+      if (z_step) count_position.z += z_dir ? 1 : -1;
     #endif
 
     AWAIT_HIGH_PULSE();