Merge pull request #11004 from ejtagle/always_honor_maximum_step_rate

[2.0.x] Fix stepper pulse minimum period and timing calculations

Marlin/src/HAL/HAL_AVR/HAL.h

   int freeMemory(void);
 }
 
-// eeprom
-//void eeprom_write_byte(unsigned char *pos, unsigned char value);
-//unsigned char eeprom_read_byte(unsigned char *pos);
-
 // timers
 #define HAL_TIMER_RATE          ((F_CPU) / 8)    // i.e., 2MHz or 2.5MHz
 
 #define TEMP_TIMER_NUM          0
 #define PULSE_TIMER_NUM         STEP_TIMER_NUM
 
-#define STEPPER_TIMER_RATE      HAL_TIMER_RATE
-#define HAL_TICKS_PER_US        ((STEPPER_TIMER_RATE) / 1000000) // Cannot be of type double
-#define STEPPER_TIMER_PRESCALE  8
-#define STEP_TIMER_MIN_INTERVAL 8 // minimum time in µs between stepper interrupts
-
 #define TEMP_TIMER_FREQUENCY    ((F_CPU) / 64.0 / 256.0)
 
-#define TIMER_OCR_1             OCR1A
-#define TIMER_COUNTER_1         TCNT1
-
-#define TIMER_OCR_0             OCR0A
-#define TIMER_COUNTER_0         TCNT0
+#define STEPPER_TIMER_RATE      HAL_TIMER_RATE
+#define STEPPER_TIMER_PRESCALE  8
+#define STEPPER_TIMER_TICKS_PER_US ((STEPPER_TIMER_RATE) / 1000000) // Cannot be of type double
 
-#define PULSE_TIMER_PRESCALE    STEPPER_TIMER_PRESCALE
+#define PULSE_TIMER_RATE       STEPPER_TIMER_RATE   // frequency of pulse timer
+#define PULSE_TIMER_PRESCALE   STEPPER_TIMER_PRESCALE
+#define PULSE_TIMER_TICKS_PER_US STEPPER_TIMER_TICKS_PER_US
 
 #define ENABLE_STEPPER_DRIVER_INTERRUPT()  SBI(TIMSK1, OCIE1A)
 #define DISABLE_STEPPER_DRIVER_INTERRUPT() CBI(TIMSK1, OCIE1A)
   }
 }
 
+#define TIMER_OCR_1             OCR1A
+#define TIMER_COUNTER_1         TCNT1
+
+#define TIMER_OCR_0             OCR0A
+#define TIMER_COUNTER_0         TCNT0
+
 #define _CAT(a, ...) a ## __VA_ARGS__
 #define HAL_timer_set_compare(timer, compare) (_CAT(TIMER_OCR_, timer) = compare)
 #define HAL_timer_restrain(timer, interval_ticks) NOLESS(_CAT(TIMER_OCR_, timer), _CAT(TIMER_COUNTER_, timer) + interval_ticks)

Marlin/src/HAL/HAL_DUE/HAL_timers_Due.h

 typedef uint32_t hal_timer_t;
 #define HAL_TIMER_TYPE_MAX 0xFFFFFFFF
 
+#define HAL_TIMER_RATE         ((F_CPU) / 2)    // frequency of timers peripherals
+
 #define STEP_TIMER_NUM 3  // index of timer to use for stepper
 #define TEMP_TIMER_NUM 4  // index of timer to use for temperature
+#define PULSE_TIMER_NUM STEP_TIMER_NUM
 #define TONE_TIMER_NUM 6  // index of timer to use for beeper tones
 
-#define HAL_TIMER_RATE         ((F_CPU) / 2)    // frequency of timers peripherals
+#define TEMP_TIMER_FREQUENCY   1000 // temperature interrupt frequency
 
 #define STEPPER_TIMER_RATE     HAL_TIMER_RATE   // frequency of stepper timer (HAL_TIMER_RATE / STEPPER_TIMER_PRESCALE)
-#define HAL_TICKS_PER_US       ((STEPPER_TIMER_RATE) / 1000000) // stepper timer ticks per µs
-#define STEPPER_TIMER_PRESCALE (CYCLES_PER_MICROSECOND / HAL_TICKS_PER_US)
-#define STEP_TIMER_MIN_INTERVAL   8 // minimum time in µs between stepper interrupts
-
-#define TEMP_TIMER_FREQUENCY   1000 // temperature interrupt frequency
+#define STEPPER_TIMER_TICKS_PER_US ((STEPPER_TIMER_RATE) / 1000000) // stepper timer ticks per µs
+#define STEPPER_TIMER_PRESCALE (CYCLES_PER_MICROSECOND / STEPPER_TIMER_TICKS_PER_US)
 
-#define PULSE_TIMER_NUM STEP_TIMER_NUM
-#define PULSE_TIMER_PRESCALE STEPPER_TIMER_PRESCALE
+#define PULSE_TIMER_RATE       STEPPER_TIMER_RATE   // frequency of pulse timer
+#define PULSE_TIMER_PRESCALE   STEPPER_TIMER_PRESCALE
+#define PULSE_TIMER_TICKS_PER_US STEPPER_TIMER_TICKS_PER_US
 
 #define ENABLE_STEPPER_DRIVER_INTERRUPT() HAL_timer_enable_interrupt(STEP_TIMER_NUM)
 #define DISABLE_STEPPER_DRIVER_INTERRUPT()  HAL_timer_disable_interrupt(STEP_TIMER_NUM)

Marlin/src/HAL/HAL_LPC1768/HAL_timers.h

 typedef uint32_t hal_timer_t;
 #define HAL_TIMER_TYPE_MAX 0xFFFFFFFF
 
+#define HAL_TIMER_RATE         ((SystemCoreClock) / 4)  // frequency of timers peripherals
+
 #define STEP_TIMER_NUM 0  // Timer Index for Stepper
 #define TEMP_TIMER_NUM 1  // Timer Index for Temperature
 #define PULSE_TIMER_NUM STEP_TIMER_NUM
 #define PWM_TIMER_NUM 3   // Timer Index for PWM
 
-#define HAL_TIMER_RATE         ((SystemCoreClock) / 4)  // frequency of timers peripherals
-#define STEPPER_TIMER_RATE     HAL_TIMER_RATE   // frequency of stepper timer (HAL_TIMER_RATE / STEPPER_TIMER_PRESCALE)
-#define HAL_TICKS_PER_US       ((STEPPER_TIMER_RATE) / 1000000) // stepper timer ticks per µs
-#define STEPPER_TIMER_PRESCALE (CYCLES_PER_MICROSECOND / HAL_TICKS_PER_US)
-
-#define STEP_TIMER_MIN_INTERVAL   8 // minimum time in µs between stepper interrupts
-
 #define TEMP_TIMER_RATE        1000000
 #define TEMP_TIMER_FREQUENCY   1000 // temperature interrupt frequency
 
-#define PULSE_TIMER_PRESCALE STEPPER_TIMER_PRESCALE
+#define STEPPER_TIMER_RATE     HAL_TIMER_RATE   // frequency of stepper timer (HAL_TIMER_RATE / STEPPER_TIMER_PRESCALE)
+#define STEPPER_TIMER_TICKS_PER_US ((STEPPER_TIMER_RATE) / 1000000) // stepper timer ticks per µs
+#define STEPPER_TIMER_PRESCALE (CYCLES_PER_MICROSECOND / STEPPER_TIMER_TICKS_PER_US)
+
+#define PULSE_TIMER_RATE       STEPPER_TIMER_RATE   // frequency of pulse timer
+#define PULSE_TIMER_PRESCALE   STEPPER_TIMER_PRESCALE
+#define PULSE_TIMER_TICKS_PER_US STEPPER_TIMER_TICKS_PER_US
 
 #define ENABLE_STEPPER_DRIVER_INTERRUPT() HAL_timer_enable_interrupt(STEP_TIMER_NUM)
 #define DISABLE_STEPPER_DRIVER_INTERRUPT() HAL_timer_disable_interrupt(STEP_TIMER_NUM)

Marlin/src/HAL/HAL_STM32F1/HAL_timers_Stm32f1.h

 typedef uint16_t hal_timer_t;
 #define HAL_TIMER_TYPE_MAX 0xFFFF
 
+#define HAL_TIMER_RATE         (F_CPU)  // frequency of timers peripherals
+
+#define STEP_TIMER_CHAN 1 // Channel of the timer to use for compare and interrupts
+#define TEMP_TIMER_CHAN 1 // Channel of the timer to use for compare and interrupts
+
 #if defined(MCU_STM32F103CB) || defined(MCU_STM32F103C8)
   #define STEP_TIMER_NUM 4 // For C8/CB boards, use timer 4
 #else
   #define STEP_TIMER_NUM 5 // for other boards, five is fine.
 #endif
-
-#define STEP_TIMER_CHAN 1 // Channel of the timer to use for compare and interrupts
 #define TEMP_TIMER_NUM 2  // index of timer to use for temperature
-#define TEMP_TIMER_CHAN 1 // Channel of the timer to use for compare and interrupts
 #define PULSE_TIMER_NUM STEP_TIMER_NUM
 
-timer_dev* get_timer_dev(int number);
-
-#define TIMER_DEV(num) get_timer_dev(num)
-
-#define STEP_TIMER_DEV TIMER_DEV(STEP_TIMER_NUM)
-#define TEMP_TIMER_DEV TIMER_DEV(TEMP_TIMER_NUM)
-
-//STM32_HAVE_TIMER(n);
+#define TEMP_TIMER_PRESCALE     1000 // prescaler for setting Temp timer, 72Khz
+#define TEMP_TIMER_FREQUENCY    1000 // temperature interrupt frequency
 
-#define HAL_TIMER_RATE         (F_CPU)  // frequency of timers peripherals
 #define STEPPER_TIMER_PRESCALE 18             // prescaler for setting stepper timer, 4Mhz
 #define STEPPER_TIMER_RATE     (HAL_TIMER_RATE / STEPPER_TIMER_PRESCALE)   // frequency of stepper timer
-#define HAL_TICKS_PER_US       ((STEPPER_TIMER_RATE) / 1000000) // stepper timer ticks per µs
-
-#define PULSE_TIMER_PRESCALE STEPPER_TIMER_PRESCALE
+#define STEPPER_TIMER_TICKS_PER_US ((STEPPER_TIMER_RATE) / 1000000) // stepper timer ticks per µs
 
-#define TEMP_TIMER_PRESCALE     1000 // prescaler for setting Temp timer, 72Khz
-#define TEMP_TIMER_FREQUENCY    1000 // temperature interrupt frequency
+#define PULSE_TIMER_RATE       STEPPER_TIMER_RATE   // frequency of pulse timer
+#define PULSE_TIMER_PRESCALE   STEPPER_TIMER_PRESCALE
+#define PULSE_TIMER_TICKS_PER_US STEPPER_TIMER_TICKS_PER_US
 
-#define STEP_TIMER_MIN_INTERVAL    8 // minimum time in µs between stepper interrupts
+timer_dev* get_timer_dev(int number);
+#define TIMER_DEV(num) get_timer_dev(num)
+#define STEP_TIMER_DEV TIMER_DEV(STEP_TIMER_NUM)
+#define TEMP_TIMER_DEV TIMER_DEV(TEMP_TIMER_NUM)
 
 #define ENABLE_STEPPER_DRIVER_INTERRUPT() timer_enable_irq(STEP_TIMER_DEV, STEP_TIMER_CHAN)
 #define DISABLE_STEPPER_DRIVER_INTERRUPT() timer_disable_irq(STEP_TIMER_DEV, STEP_TIMER_CHAN)

Marlin/src/HAL/HAL_STM32F4/HAL_timers_STM32F4.h

 #define hal_timer_t uint32_t  // TODO: One is 16-bit, one 32-bit - does this need to be checked?
 #define HAL_TIMER_TYPE_MAX 0xFFFF
 
-#define STEP_TIMER_NUM 0  // index of timer to use for stepper
-#define TEMP_TIMER_NUM 1  // index of timer to use for temperature
-
 #define HAL_TIMER_RATE         (HAL_RCC_GetSysClockFreq() / 2)  // frequency of timer peripherals
-#define STEPPER_TIMER_PRESCALE 54            // was 40,prescaler for setting stepper timer, 2Mhz
-#define STEPPER_TIMER_RATE     (HAL_TIMER_RATE / STEPPER_TIMER_PRESCALE)   // frequency of stepper timer
-#define HAL_TICKS_PER_US       ((STEPPER_TIMER_RATE) / 1000000) // stepper timer ticks per µs
 
+#define STEP_TIMER_NUM 0  // index of timer to use for stepper
+#define TEMP_TIMER_NUM 1  // index of timer to use for temperature
 #define PULSE_TIMER_NUM STEP_TIMER_NUM
-#define PULSE_TIMER_PRESCALE STEPPER_TIMER_PRESCALE
 
 #define TEMP_TIMER_PRESCALE     1000 // prescaler for setting Temp timer, 72Khz
 #define TEMP_TIMER_FREQUENCY    1000 // temperature interrupt frequency
 
-#define STEP_TIMER_MIN_INTERVAL    8 // minimum time in µs between stepper interrupts
+#define STEPPER_TIMER_PRESCALE 54 // was 40,prescaler for setting stepper timer, 2Mhz
+#define STEPPER_TIMER_RATE     (HAL_TIMER_RATE / STEPPER_TIMER_PRESCALE)   // frequency of stepper timer
+#define STEPPER_TIMER_TICKS_PER_US ((STEPPER_TIMER_RATE) / 1000000) // stepper timer ticks per µs
+
+#define PULSE_TIMER_RATE       STEPPER_TIMER_RATE   // frequency of pulse timer
+#define PULSE_TIMER_PRESCALE   STEPPER_TIMER_PRESCALE
+#define PULSE_TIMER_TICKS_PER_US STEPPER_TIMER_TICKS_PER_US
 
 #define ENABLE_STEPPER_DRIVER_INTERRUPT() HAL_timer_enable_interrupt(STEP_TIMER_NUM)
 #define DISABLE_STEPPER_DRIVER_INTERRUPT() HAL_timer_disable_interrupt(STEP_TIMER_NUM)

Marlin/src/HAL/HAL_STM32F7/HAL_timers_STM32F7.h

 #define hal_timer_t uint32_t  // TODO: One is 16-bit, one 32-bit - does this need to be checked?
 #define HAL_TIMER_TYPE_MAX 0xFFFF
 
-#define STEP_TIMER_NUM 0  // index of timer to use for stepper
-#define TEMP_TIMER_NUM 1  // index of timer to use for temperature
-
 #define HAL_TIMER_RATE         (HAL_RCC_GetSysClockFreq() / 2)  // frequency of timer peripherals
-#define STEPPER_TIMER_PRESCALE 54            // was 40,prescaler for setting stepper timer, 2Mhz
-#define STEPPER_TIMER_RATE     (HAL_TIMER_RATE / STEPPER_TIMER_PRESCALE)   // frequency of stepper timer
-#define HAL_TICKS_PER_US       ((STEPPER_TIMER_RATE) / 1000000) // stepper timer ticks per µs
 
+#define STEP_TIMER_NUM 0  // index of timer to use for stepper
+#define TEMP_TIMER_NUM 1  // index of timer to use for temperature
 #define PULSE_TIMER_NUM STEP_TIMER_NUM
-#define PULSE_TIMER_PRESCALE STEPPER_TIMER_PRESCALE
 
-#define TEMP_TIMER_PRESCALE     1000 // prescaler for setting Temp timer, 72Khz
 #define TEMP_TIMER_FREQUENCY    1000 // temperature interrupt frequency
+#define TEMP_TIMER_PRESCALE     1000 // prescaler for setting Temp timer, 72Khz
+
+#define STEPPER_TIMER_PRESCALE 54    // was 40,prescaler for setting stepper timer, 2Mhz
+#define STEPPER_TIMER_RATE     (HAL_TIMER_RATE / STEPPER_TIMER_PRESCALE)   // frequency of stepper timer
+#define STEPPER_TIMER_TICKS_PER_US ((STEPPER_TIMER_RATE) / 1000000) // stepper timer ticks per µs
 
-#define STEP_TIMER_MIN_INTERVAL    8 // minimum time in µs between stepper interrupts
+#define PULSE_TIMER_RATE       STEPPER_TIMER_RATE   // frequency of pulse timer
+#define PULSE_TIMER_PRESCALE   STEPPER_TIMER_PRESCALE
+#define PULSE_TIMER_TICKS_PER_US STEPPER_TIMER_TICKS_PER_US
 
 #define ENABLE_STEPPER_DRIVER_INTERRUPT() HAL_timer_enable_interrupt(STEP_TIMER_NUM)
 #define DISABLE_STEPPER_DRIVER_INTERRUPT() HAL_timer_disable_interrupt(STEP_TIMER_NUM)

Marlin/src/HAL/HAL_TEENSY35_36/HAL_timers_Teensy.h

 typedef uint32_t hal_timer_t;
 #define HAL_TIMER_TYPE_MAX 0xFFFFFFFF
 
-#define STEP_TIMER_NUM 0
-#define TEMP_TIMER_NUM 1
-#define PULSE_TIMER_NUM STEP_TIMER_NUM
-
 #define FTM0_TIMER_PRESCALE 8
 #define FTM1_TIMER_PRESCALE 4
 #define FTM0_TIMER_PRESCALE_BITS 0b011
 #define FTM1_TIMER_RATE (F_BUS / FTM1_TIMER_PRESCALE) // 60MHz / 4 = 15MHz
 
 #define HAL_TIMER_RATE         (FTM0_TIMER_RATE)
-#define STEPPER_TIMER_RATE     HAL_TIMER_RATE
-#define HAL_TICKS_PER_US       ((STEPPER_TIMER_RATE) / 1000000)
-#define STEPPER_TIMER_PRESCALE (CYCLES_PER_MICROSECOND / HAL_TICKS_PER_US)
-#define STEP_TIMER_MIN_INTERVAL   8 // minimum time in µs between stepper interrupts
 
-#define TEMP_TIMER_FREQUENCY   1000
+#define STEP_TIMER_NUM 0
+#define TEMP_TIMER_NUM 1
+#define PULSE_TIMER_NUM STEP_TIMER_NUM
+
+#define TEMP_TIMER_FREQUENCY    1000
+
+#define STEPPER_TIMER_RATE     HAL_TIMER_RATE
+#define STEPPER_TIMER_TICKS_PER_US ((STEPPER_TIMER_RATE) / 1000000)
+#define STEPPER_TIMER_PRESCALE (CYCLES_PER_MICROSECOND / STEPPER_TIMER_TICKS_PER_US)
 
-#define PULSE_TIMER_PRESCALE STEPPER_TIMER_PRESCALE
+#define PULSE_TIMER_RATE       STEPPER_TIMER_RATE   // frequency of pulse timer
+#define PULSE_TIMER_PRESCALE   STEPPER_TIMER_PRESCALE
+#define PULSE_TIMER_TICKS_PER_US STEPPER_TIMER_TICKS_PER_US
 
 #define ENABLE_STEPPER_DRIVER_INTERRUPT() HAL_timer_enable_interrupt(STEP_TIMER_NUM)
 #define DISABLE_STEPPER_DRIVER_INTERRUPT() HAL_timer_disable_interrupt(STEP_TIMER_NUM)

Marlin/src/inc/Conditionals_post.h

   #define USE_EXECUTE_COMMANDS_IMMEDIATE
 #endif
 
-// Calculate a default maximum stepper rate, if not supplied
-#ifndef MAXIMUM_STEPPER_RATE
-  #if MINIMUM_STEPPER_PULSE
-    #define MAXIMUM_STEPPER_RATE (1000000UL / (2UL * (MINIMUM_STEPPER_PULSE)))
-  #else
-    #define MAXIMUM_STEPPER_RATE 500000UL
-  #endif
-#endif
-
-//
-// Estimate the amount of time the ISR will take to execute
-//
-#ifdef CPU_32_BIT
-
-  // The base ISR takes 792 cycles
-  #define ISR_BASE_CYCLES  792UL
-
-  // Linear advance base time is 64 cycles
-  #if ENABLED(LIN_ADVANCE)
-    #define ISR_LA_BASE_CYCLES 64UL
-  #else
-    #define ISR_LA_BASE_CYCLES 0UL
-  #endif
-
-  // S curve interpolation adds 40 cycles
-  #if ENABLED(S_CURVE_ACCELERATION)
-    #define ISR_S_CURVE_CYCLES 40UL
-  #else
-    #define ISR_S_CURVE_CYCLES 0UL
-  #endif
-
-  // Stepper Loop base cycles
-  #define ISR_LOOP_BASE_CYCLES 4UL
-
-  // And each stepper takes 16 cycles
-  #define ISR_STEPPER_CYCLES 16UL
-
-#else
-
-  // The base ISR takes 752 cycles
-  #define ISR_BASE_CYCLES  752UL
-
-  // Linear advance base time is 32 cycles
-  #if ENABLED(LIN_ADVANCE)
-    #define ISR_LA_BASE_CYCLES 32UL
-  #else
-    #define ISR_LA_BASE_CYCLES 0UL
-  #endif
-
-  // S curve interpolation adds 160 cycles
-  #if ENABLED(S_CURVE_ACCELERATION)
-    #define ISR_S_CURVE_CYCLES 160UL
-  #else
-    #define ISR_S_CURVE_CYCLES 0UL
-  #endif
-
-  // Stepper Loop base cycles
-  #define ISR_LOOP_BASE_CYCLES 32UL
-
-  // And each stepper takes 88 cycles
-  #define ISR_STEPPER_CYCLES 88UL
-
-#endif
-
-// For each stepper, we add its time
-#ifdef HAS_X_STEP
-  #define ISR_X_STEPPER_CYCLES ISR_STEPPER_CYCLES
-#else
-  #define ISR_X_STEPPER_CYCLES 0UL
-#endif
-
-// For each stepper, we add its time
-#ifdef HAS_Y_STEP
-  #define ISR_Y_STEPPER_CYCLES ISR_STEPPER_CYCLES
-#else
-  #define ISR_Y_STEPPER_CYCLES 0UL
-#endif
-
-// For each stepper, we add its time
-#ifdef HAS_Z_STEP
-  #define ISR_Z_STEPPER_CYCLES ISR_STEPPER_CYCLES
-#else
-  #define ISR_Z_STEPPER_CYCLES 0UL
-#endif
-
-// E is always interpolated, even for mixing extruders
-#define ISR_E_STEPPER_CYCLES ISR_STEPPER_CYCLES
-
-// If linear advance is disabled, then the loop also handles them
-#if DISABLED(LIN_ADVANCE) && ENABLED(MIXING_EXTRUDER)
-  #define ISR_MIXING_STEPPER_CYCLES ((MIXING_STEPPERS) * ISR_STEPPER_CYCLES)
-#else
-  #define ISR_MIXING_STEPPER_CYCLES  0UL
-#endif
-
-// And the total minimum loop time is, without including the base
-#define MIN_ISR_LOOP_CYCLES (ISR_X_STEPPER_CYCLES + ISR_Y_STEPPER_CYCLES + ISR_Z_STEPPER_CYCLES + ISR_E_STEPPER_CYCLES + ISR_MIXING_STEPPER_CYCLES)
-
-// Calculate the minimum MPU cycles needed per pulse to enforce not surpassing the maximum stepper rate
-#define _MIN_STEPPER_PULSE_CYCLES(N) MAX((F_CPU) / (MAXIMUM_STEPPER_RATE), ((F_CPU) / 500000UL) * (N))
-#if MINIMUM_STEPPER_PULSE
-  #define MIN_STEPPER_PULSE_CYCLES _MIN_STEPPER_PULSE_CYCLES(MINIMUM_STEPPER_PULSE)
-#else
-  #define MIN_STEPPER_PULSE_CYCLES _MIN_STEPPER_PULSE_CYCLES(1)
-#endif
-
-// But the user could be enforcing a minimum time, so the loop time is
-#define ISR_LOOP_CYCLES (ISR_LOOP_BASE_CYCLES + MAX(MIN_STEPPER_PULSE_CYCLES, MIN_ISR_LOOP_CYCLES))
-
-// If linear advance is enabled, then it is handled separately
-#if ENABLED(LIN_ADVANCE)
-
-  // Estimate the minimum LA loop time
-  #if ENABLED(MIXING_EXTRUDER)
-    #define MIN_ISR_LA_LOOP_CYCLES ((MIXING_STEPPERS) * (ISR_STEPPER_CYCLES))
-  #else
-    #define MIN_ISR_LA_LOOP_CYCLES ISR_STEPPER_CYCLES
-  #endif
-
-  // And the real loop time
-  #define ISR_LA_LOOP_CYCLES MAX(MIN_STEPPER_PULSE_CYCLES, MIN_ISR_LA_LOOP_CYCLES)
-
-#else
-  #define ISR_LA_LOOP_CYCLES 0UL
-#endif
-
-// Now estimate the total ISR execution time in cycles given a step per ISR multiplier
-#define ISR_EXECUTION_CYCLES(rate) (((ISR_BASE_CYCLES + ISR_S_CURVE_CYCLES + (ISR_LOOP_CYCLES * rate) + ISR_LA_BASE_CYCLES + ISR_LA_LOOP_CYCLES)) / rate)
-
-// The maximum allowable stepping frequency when doing x128-x1 stepping (in Hz)
-#define MAX_128X_STEP_ISR_FREQUENCY (F_CPU / ISR_EXECUTION_CYCLES(128))
-#define MAX_64X_STEP_ISR_FREQUENCY  (F_CPU / ISR_EXECUTION_CYCLES(64))
-#define MAX_32X_STEP_ISR_FREQUENCY  (F_CPU / ISR_EXECUTION_CYCLES(32))
-#define MAX_16X_STEP_ISR_FREQUENCY  (F_CPU / ISR_EXECUTION_CYCLES(16))
-#define MAX_8X_STEP_ISR_FREQUENCY   (F_CPU / ISR_EXECUTION_CYCLES(8))
-#define MAX_4X_STEP_ISR_FREQUENCY   (F_CPU / ISR_EXECUTION_CYCLES(4))
-#define MAX_2X_STEP_ISR_FREQUENCY   (F_CPU / ISR_EXECUTION_CYCLES(2))
-#define MAX_1X_STEP_ISR_FREQUENCY   (F_CPU / ISR_EXECUTION_CYCLES(1))
-
-// The minimum allowable frequency for step smoothing will be 1/10 of the maximum nominal frequency (in Hz)
-#define MIN_STEP_ISR_FREQUENCY    MAX_1X_STEP_ISR_FREQUENCY
-
-// Disable multiple steps per ISR
-//#define DISABLE_MULTI_STEPPING
-
 #endif // CONDITIONALS_POST_H

Marlin/src/module/stepper.cpp

       #else
         1
       #endif
-      * (HAL_TICKS_PER_US)
+      * (STEPPER_TIMER_TICKS_PER_US)
     );
 
     /**
   // Just update the value we will get at the end of the loop
   step_events_completed += events_to_do;
 
-  #if MINIMUM_STEPPER_PULSE
-    // Get the timer count and estimate the end of the pulse
-    hal_timer_t pulse_end = HAL_timer_get_count(PULSE_TIMER_NUM) + hal_timer_t((HAL_TICKS_PER_US) * (MINIMUM_STEPPER_PULSE));
-  #endif
+  // Get the timer count and estimate the end of the pulse
+  hal_timer_t pulse_end = HAL_timer_get_count(PULSE_TIMER_NUM) + hal_timer_t(MIN_PULSE_TICKS);
+
+  const hal_timer_t added_step_ticks = ADDED_STEP_TICKS;
 
   // Take multiple steps per interrupt (For high speed moves)
   do {
     #if MINIMUM_STEPPER_PULSE
       // Just wait for the requested pulse duration
       while (HAL_timer_get_count(PULSE_TIMER_NUM) < pulse_end) { /* nada */ }
-      // Add to the value, the value needed for the pulse end and ensuring the maximum driver rate is enforced
-      pulse_end += hal_timer_t(MIN_STEPPER_PULSE_CYCLES) - hal_timer_t((HAL_TICKS_PER_US) * (MINIMUM_STEPPER_PULSE));
     #endif
 
+    // Add the delay needed to ensure the maximum driver rate is enforced
+    if (signed(added_step_ticks) > 0) pulse_end += hal_timer_t(added_step_ticks);
+
     // Pulse stop
     #if HAS_X_STEP
       PULSE_STOP(X);
     // Decrement the count of pending pulses to do
     --events_to_do;
 
-    #if MINIMUM_STEPPER_PULSE
-      // For minimum pulse time wait after stopping pulses also
-      if (events_to_do) {
-        // Just wait for the requested pulse duration
-        while (HAL_timer_get_count(PULSE_TIMER_NUM) < pulse_end) { /* nada */ }
+    // For minimum pulse time wait after stopping pulses also
+    if (events_to_do) {
+      // Just wait for the requested pulse duration
+      while (HAL_timer_get_count(PULSE_TIMER_NUM) < pulse_end) { /* nada */ }
+      #if MINIMUM_STEPPER_PULSE
         // Add to the value, the time that the pulse must be active (to be used on the next loop)
-        pulse_end += hal_timer_t((HAL_TICKS_PER_US) * (MINIMUM_STEPPER_PULSE));
-      }
-    #endif
+        pulse_end += hal_timer_t(MIN_PULSE_TICKS);
+      #endif
+    }
 
   } while (events_to_do);
 }
         uint32_t max_rate = current_block->nominal_rate;  // Get the maximum rate (maximum event speed)
         while (max_rate < MIN_STEP_ISR_FREQUENCY) {
           max_rate <<= 1;
-          if (max_rate >= MAX_1X_STEP_ISR_FREQUENCY) break;
+          if (max_rate >= MAX_STEP_ISR_FREQUENCY_1X) break;
           ++oversampling;
         }
         oversampling_factor = oversampling;
           REV_E_DIR(active_extruder);
       #endif
 
+    // Get the timer count and estimate the end of the pulse
+    hal_timer_t pulse_end = HAL_timer_get_count(PULSE_TIMER_NUM) + hal_timer_t(MIN_PULSE_TICKS);
+
+    const hal_timer_t added_step_ticks = ADDED_STEP_TICKS;
+
     // Step E stepper if we have steps
     while (LA_steps) {
 
-      #if MINIMUM_STEPPER_PULSE
-        hal_timer_t pulse_end = HAL_timer_get_count(PULSE_TIMER_NUM) + hal_timer_t((HAL_TICKS_PER_US) * (MINIMUM_STEPPER_PULSE));
-      #endif
-
+      // Set the STEP pulse ON
       #if ENABLED(MIXING_EXTRUDER)
         MIXING_STEPPERS_LOOP(j) {
           // Step mixing steppers (proportionally)
         E_STEP_WRITE(active_extruder, !INVERT_E_STEP_PIN);
       #endif
 
+      // Enforce a minimum duration for STEP pulse ON
       #if MINIMUM_STEPPER_PULSE
         // Just wait for the requested pulse duration
         while (HAL_timer_get_count(PULSE_TIMER_NUM) < pulse_end) { /* nada */ }
-        // Add to the value, the value needed for the pulse end and ensuring the maximum driver rate is enforced
-        pulse_end += hal_timer_t(MIN_STEPPER_PULSE_CYCLES) - hal_timer_t((HAL_TICKS_PER_US) * (MINIMUM_STEPPER_PULSE));
       #endif
 
+      // Add the delay needed to ensure the maximum driver rate is enforced
+      if (signed(added_step_ticks) > 0) pulse_end += hal_timer_t(added_step_ticks);
+
       LA_steps < 0 ? ++LA_steps : --LA_steps;
 
+      // Set the STEP pulse OFF
       #if ENABLED(MIXING_EXTRUDER)
         MIXING_STEPPERS_LOOP(j) {
           if (delta_error_m[j] >= 0) {
         E_STEP_WRITE(active_extruder, INVERT_E_STEP_PIN);
       #endif
 
-      #if MINIMUM_STEPPER_PULSE
-        // For minimum pulse time wait before looping
-        // Just wait for the requested pulse duration
-        if (LA_steps) while (HAL_timer_get_count(PULSE_TIMER_NUM) < pulse_end) { /* nada */ }
-      #endif
-
+      // For minimum pulse time wait before looping
+      // Just wait for the requested pulse duration
+      if (LA_steps) {
+        while (HAL_timer_get_count(PULSE_TIMER_NUM) < pulse_end) { /* nada */ }
+        #if MINIMUM_STEPPER_PULSE
+          // Add to the value, the time that the pulse must be active (to be used on the next loop)
+          pulse_end += hal_timer_t(MIN_PULSE_TICKS);
+        #endif
+      }
     } // LA_steps
 
     return interval;

Marlin/src/module/stepper.h

 #ifndef STEPPER_H
 #define STEPPER_H
 
+#include "../inc/MarlinConfig.h"
+
+// Disable multiple steps per ISR
+//#define DISABLE_MULTI_STEPPING
+
+//
+// Estimate the amount of time the Stepper ISR will take to execute
+//
+
+#ifndef MINIMUM_STEPPER_PULSE
+  #define MINIMUM_STEPPER_PULSE 0
+#endif
+
+#ifndef MAXIMUM_STEPPER_RATE
+  #if MINIMUM_STEPPER_PULSE
+    #define MAXIMUM_STEPPER_RATE (1000000UL / (2UL * (MINIMUM_STEPPER_PULSE)))
+  #else
+    #define MAXIMUM_STEPPER_RATE 500000UL
+  #endif
+#endif
+
+#ifdef CPU_32_BIT
+
+  // The base ISR takes 792 cycles
+  #define ISR_BASE_CYCLES  792UL
+
+  // Linear advance base time is 64 cycles
+  #if ENABLED(LIN_ADVANCE)
+    #define ISR_LA_BASE_CYCLES 64UL
+  #else
+    #define ISR_LA_BASE_CYCLES 0UL
+  #endif
+
+  // S curve interpolation adds 40 cycles
+  #if ENABLED(S_CURVE_ACCELERATION)
+    #define ISR_S_CURVE_CYCLES 40UL
+  #else
+    #define ISR_S_CURVE_CYCLES 0UL
+  #endif
+
+  // Stepper Loop base cycles
+  #define ISR_LOOP_BASE_CYCLES 4UL
+
+  // And each stepper takes 16 cycles
+  #define ISR_STEPPER_CYCLES 16UL
+
+#else
+
+  // The base ISR takes 752 cycles
+  #define ISR_BASE_CYCLES  752UL
+
+  // Linear advance base time is 32 cycles
+  #if ENABLED(LIN_ADVANCE)
+    #define ISR_LA_BASE_CYCLES 32UL
+  #else
+    #define ISR_LA_BASE_CYCLES 0UL
+  #endif
+
+  // S curve interpolation adds 160 cycles
+  #if ENABLED(S_CURVE_ACCELERATION)
+    #define ISR_S_CURVE_CYCLES 160UL
+  #else
+    #define ISR_S_CURVE_CYCLES 0UL
+  #endif
+
+  // Stepper Loop base cycles
+  #define ISR_LOOP_BASE_CYCLES 32UL
+
+  // And each stepper takes 88 cycles
+  #define ISR_STEPPER_CYCLES 88UL
+
+#endif
+
+// Add time for each stepper
+#ifdef HAS_X_STEP
+  #define ISR_X_STEPPER_CYCLES ISR_STEPPER_CYCLES
+#else
+  #define ISR_X_STEPPER_CYCLES 0UL
+#endif
+#ifdef HAS_Y_STEP
+  #define ISR_Y_STEPPER_CYCLES ISR_STEPPER_CYCLES
+#else
+  #define ISR_Y_STEPPER_CYCLES 0UL
+#endif
+#ifdef HAS_Z_STEP
+  #define ISR_Z_STEPPER_CYCLES ISR_STEPPER_CYCLES
+#else
+  #define ISR_Z_STEPPER_CYCLES 0UL
+#endif
+
+// E is always interpolated, even for mixing extruders
+#define ISR_E_STEPPER_CYCLES ISR_STEPPER_CYCLES
+
+// If linear advance is disabled, then the loop also handles them
+#if DISABLED(LIN_ADVANCE) && ENABLED(MIXING_EXTRUDER)
+  #define ISR_MIXING_STEPPER_CYCLES ((MIXING_STEPPERS) * (ISR_STEPPER_CYCLES))
+#else
+  #define ISR_MIXING_STEPPER_CYCLES  0UL
+#endif
+
+// And the total minimum loop time, not including the base
+#define MIN_ISR_LOOP_CYCLES (ISR_X_STEPPER_CYCLES + ISR_Y_STEPPER_CYCLES + ISR_Z_STEPPER_CYCLES + ISR_E_STEPPER_CYCLES + ISR_MIXING_STEPPER_CYCLES)
+
+// Calculate the minimum MPU cycles needed per pulse to enforce, limited to the max stepper rate
+#define _MIN_STEPPER_PULSE_CYCLES(N) max((F_CPU) / (MAXIMUM_STEPPER_RATE), ((F_CPU) / 500000UL) * (N))
+#if MINIMUM_STEPPER_PULSE
+  #define MIN_STEPPER_PULSE_CYCLES _MIN_STEPPER_PULSE_CYCLES(MINIMUM_STEPPER_PULSE)
+#else
+  #define MIN_STEPPER_PULSE_CYCLES _MIN_STEPPER_PULSE_CYCLES(1)
+#endif
+
+#define MIN_PULSE_TICKS  ((PULSE_TIMER_TICKS_PER_US) * (MINIMUM_STEPPER_PULSE))
+#define ADDED_STEP_TICKS ((MIN_STEPPER_PULSE_CYCLES) / (PULSE_TIMER_PRESCALE) - MIN_PULSE_TICKS)
+
+// But the user could be enforcing a minimum time, so the loop time is
+#define ISR_LOOP_CYCLES (ISR_LOOP_BASE_CYCLES + max(MIN_STEPPER_PULSE_CYCLES, MIN_ISR_LOOP_CYCLES))
+
+// If linear advance is enabled, then it is handled separately
+#if ENABLED(LIN_ADVANCE)
+
+  // Estimate the minimum LA loop time
+  #if ENABLED(MIXING_EXTRUDER)
+    #define MIN_ISR_LA_LOOP_CYCLES ((MIXING_STEPPERS) * (ISR_STEPPER_CYCLES))
+  #else
+    #define MIN_ISR_LA_LOOP_CYCLES ISR_STEPPER_CYCLES
+  #endif
+
+  // And the real loop time
+  #define ISR_LA_LOOP_CYCLES max(MIN_STEPPER_PULSE_CYCLES, MIN_ISR_LA_LOOP_CYCLES)
+
+#else
+  #define ISR_LA_LOOP_CYCLES 0UL
+#endif
+
+// Now estimate the total ISR execution time in cycles given a step per ISR multiplier
+#define ISR_EXECUTION_CYCLES(R) (((ISR_BASE_CYCLES + ISR_S_CURVE_CYCLES + (ISR_LOOP_CYCLES) * (R) + ISR_LA_BASE_CYCLES + ISR_LA_LOOP_CYCLES)) / (R))
+
+// The maximum allowable stepping frequency when doing x128-x1 stepping (in Hz)
+#define MAX_STEP_ISR_FREQUENCY_128X ((F_CPU) / ISR_EXECUTION_CYCLES(128))
+#define MAX_STEP_ISR_FREQUENCY_64X  ((F_CPU) / ISR_EXECUTION_CYCLES(64))
+#define MAX_STEP_ISR_FREQUENCY_32X  ((F_CPU) / ISR_EXECUTION_CYCLES(32))
+#define MAX_STEP_ISR_FREQUENCY_16X  ((F_CPU) / ISR_EXECUTION_CYCLES(16))
+#define MAX_STEP_ISR_FREQUENCY_8X   ((F_CPU) / ISR_EXECUTION_CYCLES(8))
+#define MAX_STEP_ISR_FREQUENCY_4X   ((F_CPU) / ISR_EXECUTION_CYCLES(4))
+#define MAX_STEP_ISR_FREQUENCY_2X   ((F_CPU) / ISR_EXECUTION_CYCLES(2))
+#define MAX_STEP_ISR_FREQUENCY_1X   ((F_CPU) / ISR_EXECUTION_CYCLES(1))
+
+// The minimum allowable frequency for step smoothing will be 1/10 of the maximum nominal frequency (in Hz)
+#define MIN_STEP_ISR_FREQUENCY MAX_STEP_ISR_FREQUENCY_1X
+
+//
+// Stepper class definition
+//
+
 #include "stepper_indirection.h"
 
 #ifdef __AVR__
   #include "speed_lookuptable.h"
 #endif
 
-#include "../inc/MarlinConfig.h"
 #include "../module/planner.h"
 #include "../core/language.h"
 
-class Stepper;
-extern Stepper stepper;
-
 class Stepper {
 
   public:
 
         // The stepping frequency limits for each multistepping rate
         static const uint32_t limit[] PROGMEM = {
-          (  MAX_1X_STEP_ISR_FREQUENCY     ),
-          (  MAX_2X_STEP_ISR_FREQUENCY >> 1),
-          (  MAX_4X_STEP_ISR_FREQUENCY >> 2),
-          (  MAX_8X_STEP_ISR_FREQUENCY >> 3),
-          ( MAX_16X_STEP_ISR_FREQUENCY >> 4),
-          ( MAX_32X_STEP_ISR_FREQUENCY >> 5),
-          ( MAX_64X_STEP_ISR_FREQUENCY >> 6),
-          (MAX_128X_STEP_ISR_FREQUENCY >> 7)
+          (  MAX_STEP_ISR_FREQUENCY_1X     ),
+          (  MAX_STEP_ISR_FREQUENCY_2X >> 1),
+          (  MAX_STEP_ISR_FREQUENCY_4X >> 2),
+          (  MAX_STEP_ISR_FREQUENCY_8X >> 3),
+          ( MAX_STEP_ISR_FREQUENCY_16X >> 4),
+          ( MAX_STEP_ISR_FREQUENCY_32X >> 5),
+          ( MAX_STEP_ISR_FREQUENCY_64X >> 6),
+          (MAX_STEP_ISR_FREQUENCY_128X >> 7)
         };
 
         // Select the proper multistepping
           ++idx;
         };
       #else
-        NOMORE(step_rate, uint32_t(MAX_1X_STEP_ISR_FREQUENCY));
+        NOMORE(step_rate, uint32_t(MAX_STEP_ISR_FREQUENCY_1X));
       #endif
       *loops = multistep;
 
 
 };
 
+extern Stepper stepper;
+
 #endif // STEPPER_H