HAL function to ensure min stepper interrupt interval (#9985)

Marlin/src/HAL/HAL_AVR/HAL_AVR.h

@@ -126,6 +126,8 @@ extern "C" {
 #define HAL_STEPPER_TIMER_RATE  HAL_TIMER_RATE
 #define STEPPER_TIMER_PRESCALE  8
 
+#define STEP_TIMER_MIN_INTERVAL 8 // minimum time in µs between stepper interrupts
+
 #define STEP_TIMER_NUM          1
 #define TIMER_OCR_1             OCR1A
 #define TIMER_COUNTER_1         TCNT1
@@ -148,6 +150,8 @@ extern "C" {
 
 #define _CAT(a, ...) a ## __VA_ARGS__
 #define HAL_timer_set_compare(timer, compare) (_CAT(TIMER_OCR_, timer) = compare)
+#define HAL_timer_restrain(timer, interval_µs) NOLESS(_CAT(TIMER_OCR_, timer), _CAT(TIMER_COUNTER_, timer) + interval_µs * HAL_TICKS_PER_US)
+
 #define HAL_timer_get_compare(timer) _CAT(TIMER_OCR_, timer)
 #define HAL_timer_get_count(timer) _CAT(TIMER_COUNTER_, timer)
 

Marlin/src/HAL/HAL_AVR/HAL_spi_AVR.cpp

@@ -221,7 +221,7 @@ void spiBegin (void) {
   /** Soft SPI receive byte */
   uint8_t spiRec() {
     uint8_t data = 0;
-    // no interrupts during byte receive - about 8 us
+    // no interrupts during byte receive - about 8µs
     cli();
     // output pin high - like sending 0xFF
     WRITE(MOSI_PIN, HIGH);
@@ -252,7 +252,7 @@ void spiBegin (void) {
   //------------------------------------------------------------------------------
   /** Soft SPI send byte */
   void spiSend(uint8_t data) {
-    // no interrupts during byte send - about 8 us
+    // no interrupts during byte send - about 8µs
     cli();
     for (uint8_t i = 0; i < 8; i++) {
       WRITE(SCK_PIN, LOW);

Marlin/src/HAL/HAL_DUE/HAL_timers_Due.h

@@ -50,9 +50,10 @@ typedef uint32_t hal_timer_t;
 #define HAL_TIMER_RATE         ((F_CPU) / 2)    // frequency of timers peripherals
 #define STEPPER_TIMER_PRESCALE 1.0              // prescaler for setting stepper frequency
 #define HAL_STEPPER_TIMER_RATE HAL_TIMER_RATE   // frequency of stepper timer (HAL_TIMER_RATE / STEPPER_TIMER_PRESCALE)
-#define HAL_TICKS_PER_US       ((HAL_STEPPER_TIMER_RATE) / 1000000) // stepper timer ticks per us
+#define HAL_TICKS_PER_US       ((HAL_STEPPER_TIMER_RATE) / 1000000) // stepper timer ticks per µs
 
 #define TEMP_TIMER_FREQUENCY   1000 // temperature interrupt frequency
+#define STEP_TIMER_MIN_INTERVAL   8 // minimum time in µs between stepper interrupts
 
 #define ENABLE_STEPPER_DRIVER_INTERRUPT() HAL_timer_enable_interrupt(STEP_TIMER_NUM)
 #define DISABLE_STEPPER_DRIVER_INTERRUPT()  HAL_timer_disable_interrupt(STEP_TIMER_NUM)
@@ -108,6 +109,11 @@ FORCE_INLINE static hal_timer_t HAL_timer_get_count(const uint8_t timer_num) {
   return pConfig->pTimerRegs->TC_CHANNEL[pConfig->channel].TC_CV;
 }
 
+FORCE_INLINE static void HAL_timer_restrain(const uint8_t timer_num, const uint16_t interval_µs) {
+  const hal_timer_t mincmp = HAL_timer_get_count(timer_num) + interval_µs * HAL_TICKS_PER_US;
+  if (HAL_timer_get_compare(timer_num) < mincmp) HAL_timer_set_compare(timer_num, mincmp);
+}
+
 void HAL_timer_enable_interrupt(const uint8_t timer_num);
 void HAL_timer_disable_interrupt(const uint8_t timer_num);
 bool HAL_timer_interrupt_enabled(const uint8_t timer_num);

Marlin/src/HAL/HAL_LPC1768/HAL_timers.h

@@ -49,10 +49,12 @@ typedef uint32_t hal_timer_t;
 #define HAL_TIMER_RATE         ((SystemCoreClock) / 4)  // frequency of timers peripherals
 #define STEPPER_TIMER_PRESCALE 1.0              // prescaler for setting stepper frequency
 #define HAL_STEPPER_TIMER_RATE HAL_TIMER_RATE   // frequency of stepper timer (HAL_TIMER_RATE / STEPPER_TIMER_PRESCALE)
-#define HAL_TICKS_PER_US       ((HAL_STEPPER_TIMER_RATE) / 1000000) // stepper timer ticks per us
+#define HAL_TICKS_PER_US       ((HAL_STEPPER_TIMER_RATE) / 1000000) // stepper timer ticks per µs
 #define HAL_TEMP_TIMER_RATE    1000000
 #define TEMP_TIMER_FREQUENCY   1000 // temperature interrupt frequency
 
+#define STEP_TIMER_MIN_INTERVAL   8 // minimum time in µs between stepper interrupts
+
 #define PULSE_TIMER_NUM STEP_TIMER_NUM
 #define PULSE_TIMER_PRESCALE STEPPER_TIMER_PRESCALE
 
@@ -118,6 +120,11 @@ FORCE_INLINE static hal_timer_t HAL_timer_get_count(const uint8_t timer_num) {
   return 0;
 }
 
+FORCE_INLINE static void HAL_timer_restrain(const uint8_t timer_num, const uint16_t interval_µs) {
+  const hal_timer_t mincmp = HAL_timer_get_count(timer_num) + interval_µs * HAL_TICKS_PER_US;
+  if (HAL_timer_get_compare(timer_num) < mincmp) HAL_timer_set_compare(timer_num, mincmp);
+}
+
 void HAL_timer_enable_interrupt(const uint8_t timer_num);
 void HAL_timer_disable_interrupt(const uint8_t timer_num);
 bool HAL_timer_interrupt_enabled(const uint8_t timer_num);

Marlin/src/HAL/HAL_STM32F1/HAL_timers_Stm32f1.h

@@ -67,7 +67,7 @@ typedef uint16_t hal_timer_t;
 #define HAL_TIMER_RATE         (F_CPU)  // frequency of timers peripherals
 #define STEPPER_TIMER_PRESCALE 18             // prescaler for setting stepper timer, 4Mhz
 #define HAL_STEPPER_TIMER_RATE (HAL_TIMER_RATE / STEPPER_TIMER_PRESCALE)   // frequency of stepper timer (HAL_TIMER_RATE / STEPPER_TIMER_PRESCALE)
-#define HAL_TICKS_PER_US       ((HAL_STEPPER_TIMER_RATE) / 1000000) // stepper timer ticks per us
+#define HAL_TICKS_PER_US       ((HAL_STEPPER_TIMER_RATE) / 1000000) // stepper timer ticks per µs
 
 #define PULSE_TIMER_NUM STEP_TIMER_NUM
 #define PULSE_TIMER_PRESCALE STEPPER_TIMER_PRESCALE
@@ -75,6 +75,8 @@ typedef uint16_t hal_timer_t;
 #define TEMP_TIMER_PRESCALE     1000 // prescaler for setting Temp timer, 72Khz
 #define TEMP_TIMER_FREQUENCY     100 // temperature interrupt frequency
 
+#define STEP_TIMER_MIN_INTERVAL    8 // minimum time in µs between stepper interrupts
+
 #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)
 #define STEPPER_ISR_ENABLED() HAL_timer_interrupt_enabled(STEP_TIMER_NUM)
@@ -152,6 +154,11 @@ FORCE_INLINE static hal_timer_t HAL_timer_get_compare(const uint8_t timer_num) {
   }
 }
 
+FORCE_INLINE static void HAL_timer_restrain(const uint8_t timer_num, const uint16_t interval_µs) {
+  const hal_timer_t mincmp = HAL_timer_get_count(timer_num) + interval_µs * HAL_TICKS_PER_US;
+  if (HAL_timer_get_compare(timer_num) < mincmp) HAL_timer_set_compare(timer_num, mincmp);
+}
+
 FORCE_INLINE static void HAL_timer_isr_prologue(const uint8_t timer_num) {
   switch (timer_num) {
   case STEP_TIMER_NUM:

Marlin/src/HAL/HAL_STM32F7/HAL_timers_STM32F7.cpp

@@ -137,6 +137,11 @@ uint32_t HAL_timer_get_count(const uint8_t timer_num) {
   return __HAL_TIM_GetCounter(&timerConfig[timer_num].timerdef);
 }
 
+void HAL_timer_restrain(const uint8_t timer_num, const uint16_t interval_µs) {
+  const hal_timer_t mincmp = HAL_timer_get_count(timer_num) + interval_µs * HAL_TICKS_PER_US;
+  if (HAL_timer_get_compare(timer_num) < mincmp) HAL_timer_set_compare(timer_num, mincmp);
+}
+
 void HAL_timer_isr_prologue(const uint8_t timer_num) {
   if (__HAL_TIM_GET_FLAG(&timerConfig[timer_num].timerdef, TIM_FLAG_UPDATE) == SET) {
     __HAL_TIM_CLEAR_FLAG(&timerConfig[timer_num].timerdef, TIM_FLAG_UPDATE);

Marlin/src/HAL/HAL_STM32F7/HAL_timers_STM32F7.h

@@ -44,7 +44,7 @@
 #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 HAL_STEPPER_TIMER_RATE (HAL_TIMER_RATE / STEPPER_TIMER_PRESCALE)   // frequency of stepper timer (HAL_TIMER_RATE / STEPPER_TIMER_PRESCALE)
-#define HAL_TICKS_PER_US       ((HAL_STEPPER_TIMER_RATE) / 1000000) // stepper timer ticks per us
+#define HAL_TICKS_PER_US       ((HAL_STEPPER_TIMER_RATE) / 1000000) // stepper timer ticks per µs
 
 #define PULSE_TIMER_NUM STEP_TIMER_NUM
 #define PULSE_TIMER_PRESCALE STEPPER_TIMER_PRESCALE
@@ -52,6 +52,8 @@
 #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 ENABLE_STEPPER_DRIVER_INTERRUPT() HAL_timer_enable_interrupt(STEP_TIMER_NUM)
 #define DISABLE_STEPPER_DRIVER_INTERRUPT() HAL_timer_disable_interrupt(STEP_TIMER_NUM)
 
@@ -94,6 +96,7 @@ void HAL_timer_disable_interrupt(const uint8_t timer_num);
 void HAL_timer_set_compare(const uint8_t timer_num, const uint32_t compare);
 hal_timer_t HAL_timer_get_compare(const uint8_t timer_num);
 uint32_t HAL_timer_get_count(const uint8_t timer_num);
+void HAL_timer_restrain(const uint8_t timer_num, const uint16_t interval_µs);
 
 void HAL_timer_isr_prologue(const uint8_t timer_num);
 

Marlin/src/HAL/HAL_TEENSY35_36/HAL_timers_Teensy.h

@@ -66,6 +66,8 @@ typedef uint32_t hal_timer_t;
 
 #define TEMP_TIMER_FREQUENCY   1000
 
+#define STEP_TIMER_MIN_INTERVAL   8 // minimum time in µs between stepper interrupts
+
 #define ENABLE_STEPPER_DRIVER_INTERRUPT() HAL_timer_enable_interrupt(STEP_TIMER_NUM)
 #define DISABLE_STEPPER_DRIVER_INTERRUPT() HAL_timer_disable_interrupt(STEP_TIMER_NUM)
 #define STEPPER_ISR_ENABLED() HAL_timer_interrupt_enabled(STEP_TIMER_NUM)
@@ -103,6 +105,11 @@ FORCE_INLINE static hal_timer_t HAL_timer_get_count(const uint8_t timer_num) {
   return 0;
 }
 
+FORCE_INLINE static void HAL_timer_restrain(const uint8_t timer_num, const uint16_t interval_µs) {
+  const hal_timer_t mincmp = HAL_timer_get_count(timer_num) + interval_µs * HAL_TICKS_PER_US;
+  if (HAL_timer_get_compare(timer_num) < mincmp) HAL_timer_set_compare(timer_num, mincmp);
+}
+
 void HAL_timer_enable_interrupt(const uint8_t timer_num);
 void HAL_timer_disable_interrupt(const uint8_t timer_num);
 bool HAL_timer_interrupt_enabled(const uint8_t timer_num);

Marlin/src/module/stepper.cpp

@@ -365,11 +365,7 @@ void Stepper::isr() {
     _NEXT_ISR(ocr_val);
 
     #if DISABLED(LIN_ADVANCE)
-      #ifdef CPU_32_BIT
+      HAL_timer_restrain(STEP_TIMER_NUM, STEP_TIMER_MIN_INTERVAL);
-        HAL_timer_set_compare(STEP_TIMER_NUM, ocr_val);
-      #else
-        NOLESS(OCR1A, TCNT1 + 16);
-      #endif
       HAL_ENABLE_ISRs(); // re-enable ISRs
     #endif
 
@@ -731,14 +727,7 @@ void Stepper::isr() {
   }
 
   #if DISABLED(LIN_ADVANCE)
-    #ifdef CPU_32_BIT
+    HAL_timer_restrain(STEP_TIMER_NUM, STEP_TIMER_MIN_INTERVAL);
-      // Make sure stepper interrupt does not monopolise CPU by adjusting count to give about 8 us room
-      hal_timer_t stepper_timer_count = HAL_timer_get_compare(STEP_TIMER_NUM),
-                  stepper_timer_current_count = HAL_timer_get_count(STEP_TIMER_NUM) + 8 * HAL_TICKS_PER_US;
-      HAL_timer_set_compare(STEP_TIMER_NUM, max(stepper_timer_count, stepper_timer_current_count));
-    #else
-      NOLESS(OCR1A, TCNT1 + 16);
-    #endif
   #endif
 
   // If current block is finished, reset pointer
@@ -901,14 +890,8 @@ void Stepper::isr() {
     }
 
     // Don't run the ISR faster than possible
-    #ifdef CPU_32_BIT
+    // Make sure stepper interrupt does not monopolise CPU by adjusting compare to give about 8µs room
-      // Make sure stepper interrupt does not monopolise CPU by adjusting count to give about 8 us room
+    HAL_timer_restrain(STEP_TIMER_NUM, STEP_TIMER_MIN_INTERVAL);
-      uint32_t stepper_timer_count = HAL_timer_get_compare(STEP_TIMER_NUM),
-               stepper_timer_current_count = HAL_timer_get_count(STEP_TIMER_NUM) + 8 * HAL_TICKS_PER_US;
-      HAL_timer_set_compare(STEP_TIMER_NUM, max(stepper_timer_count, stepper_timer_current_count));
-    #else
-      NOLESS(OCR1A, TCNT1 + 16);
-    #endif
 
     // Restore original ISR settings
     HAL_ENABLE_ISRs();