🔧 Expose MULTISTEPPING_LIMIT option

Co-Authored-By: tombrazier <68918209+tombrazier@users.noreply.github.com>

Marlin/Configuration_adv.h

@@ -1267,6 +1267,12 @@
   #endif
 #endif
 
+/**
+ * Multi-stepping sends steps in bursts to reduce MCU usage for high step-rates.
+ * This allows higher feedrates than the MCU could otherwise support.
+ */
+#define MULTISTEPPING_LIMIT   16  //: [1, 2, 4, 8, 16, 32, 64, 128]
+
 /**
  * Adaptive Step Smoothing increases the resolution of multi-axis moves, particularly at step frequencies
  * below 1kHz (for AVR) or 10kHz (for ARM), where aliasing between axes in multi-axis moves causes audible

Marlin/src/inc/Conditionals_adv.h

@@ -1219,3 +1219,9 @@
   #undef TC_GCODE_USE_GLOBAL_Y
   #undef TC_GCODE_USE_GLOBAL_Z
 #endif
+
+// Multi-Stepping Limit
+#ifndef MULTISTEPPING_LIMIT
+  #define MULTISTEPPING_LIMIT 128
+  #define MULTISTEPPING_LIMIT_WARNING 1
+#endif

Marlin/src/inc/SanityCheck.h

@@ -4500,6 +4500,9 @@ static_assert(_PLUS_TEST(4), "HOMING_FEEDRATE_MM_M values must be positive.");
   #endif
 #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.");
+
 // Misc. Cleanup
 #undef _TEST_PWM
 #undef _NUM_AXES_STR

Marlin/src/inc/Warnings.cpp

@@ -797,3 +797,7 @@
 #if HAS_SHAPING && ANY(CORE_IS_XY, MARKFORGED_XY, MARKFORGED_YX)
   #warning "Input Shaping for CORE / MARKFORGED kinematic axes is still experimental."
 #endif
+
+#if MULTISTEPPING_LIMIT_WARNING
+  #warning "MULTISTEPPING_LIMIT has been automatically set to 128. Use a lower value if the machine is slow to respond."
+#endif

Marlin/src/module/stepper.cpp

@@ -189,7 +189,10 @@ bool Stepper::abort_current_block;
 #endif
 
 uint32_t Stepper::acceleration_time, Stepper::deceleration_time;
-uint8_t Stepper::steps_per_isr = 1;   // Count of steps to perform per Stepper ISR call
+
+#if MULTISTEPPING_LIMIT > 1
+  uint8_t Stepper::steps_per_isr = 1; // Count of steps to perform per Stepper ISR call
+#endif
 
 #if ENABLED(FREEZE_FEATURE)
   bool Stepper::frozen; // = false
@@ -2089,7 +2092,7 @@ hal_timer_t Stepper::calc_timer_interval(uint32_t step_rate) {
 
 // Get the timer interval and the number of loops to perform per tick
 hal_timer_t Stepper::calc_multistep_timer_interval(uint32_t step_rate) {
-  #if ENABLED(DISABLE_MULTI_STEPPING)
+  #if MULTISTEPPING_LIMIT == 1
 
     // Just make sure the step rate is doable
     NOMORE(step_rate, uint32_t(MAX_STEP_ISR_FREQUENCY_1X));
@@ -2098,19 +2101,31 @@ hal_timer_t Stepper::calc_multistep_timer_interval(uint32_t step_rate) {
 
     // The stepping frequency limits for each multistepping rate
     static const uint32_t limit[] PROGMEM = {
-      (  MAX_STEP_ISR_FREQUENCY_1X     ),
+          (  MAX_STEP_ISR_FREQUENCY_1X     )
-      (  MAX_STEP_ISR_FREQUENCY_2X >> 1),
+        , (  MAX_STEP_ISR_FREQUENCY_2X >> 1)
-      (  MAX_STEP_ISR_FREQUENCY_4X >> 2),
+      #if MULTISTEPPING_LIMIT >= 4
-      (  MAX_STEP_ISR_FREQUENCY_8X >> 3),
+        , (  MAX_STEP_ISR_FREQUENCY_4X >> 2)
-      ( MAX_STEP_ISR_FREQUENCY_16X >> 4),
+      #endif
-      ( MAX_STEP_ISR_FREQUENCY_32X >> 5),
+      #if MULTISTEPPING_LIMIT >= 8
-      ( MAX_STEP_ISR_FREQUENCY_64X >> 6),
+        , (  MAX_STEP_ISR_FREQUENCY_8X >> 3)
-      (MAX_STEP_ISR_FREQUENCY_128X >> 7)
+      #endif
+      #if MULTISTEPPING_LIMIT >= 16
+        , ( MAX_STEP_ISR_FREQUENCY_16X >> 4)
+      #endif
+      #if MULTISTEPPING_LIMIT >= 32
+        , ( MAX_STEP_ISR_FREQUENCY_32X >> 5)
+      #endif
+      #if MULTISTEPPING_LIMIT >= 64
+        , ( MAX_STEP_ISR_FREQUENCY_64X >> 6)
+      #endif
+      #if MULTISTEPPING_LIMIT >= 128
+        , (MAX_STEP_ISR_FREQUENCY_128X >> 7)
+      #endif
     };
 
     // Find a doable step rate using multistepping
     uint8_t multistep = 1;
-    for (uint8_t i = 0; i < 7 && step_rate > uint32_t(pgm_read_dword(&limit[i])); ++i) {
+    for (uint8_t i = 0; i < COUNT(limit) && step_rate > uint32_t(pgm_read_dword(&limit[i])); ++i) {
       step_rate >>= 1;
       multistep <<= 1;
     }

Marlin/src/module/stepper.h

@@ -49,9 +49,6 @@
   #include "stepper/speed_lookuptable.h"
 #endif
 
-// Disable multiple steps per ISR
-//#define DISABLE_MULTI_STEPPING
-
 //
 // Estimate the amount of time the Stepper ISR will take to execute
 //
@@ -259,7 +256,7 @@
 
 // The minimum step ISR rate used by ADAPTIVE_STEP_SMOOTHING to target 50% CPU usage
 // This does not account for the possibility of multi-stepping.
-// Perhaps DISABLE_MULTI_STEPPING should be required with ADAPTIVE_STEP_SMOOTHING.
+// Should a MULTISTEPPING_LIMIT of 1 should be required with ADAPTIVE_STEP_SMOOTHING?
 #define MIN_STEP_ISR_FREQUENCY (MAX_STEP_ISR_FREQUENCY_1X / 2)
 
 #define ENABLE_COUNT (NUM_AXES + E_STEPPERS)
@@ -543,7 +540,12 @@ class Stepper {
     #endif
 
     static uint32_t acceleration_time, deceleration_time; // time measured in Stepper Timer ticks
-    static uint8_t steps_per_isr;         // Count of steps to perform per Stepper ISR call
+
+    #if MULTISTEPPING_LIMIT == 1
+      static constexpr uint8_t steps_per_isr = 1; // Count of steps to perform per Stepper ISR call
+    #else
+      static uint8_t steps_per_isr;
+    #endif
 
     #if ENABLED(ADAPTIVE_STEP_SMOOTHING)
       static uint8_t oversampling_factor; // Oversampling factor (log2(multiplier)) to increase temporal resolution of axis