esp32: add engine->task_rate(uint8_t delay_ms) function to adjust the stepper task rate to e.g. 1ms (see #288 for reference)

Author: gin66

CHANGELOG.md

@@ -5,6 +5,9 @@ TODO:
 - rename RampConstAcceleration to e.g. RampControl
 - for esp-idf 5 make use of espressif resource management of rmt channels
 
+0.31.3:
+- esp32: add `engine->task_rate(uint8_t delay_ms)` function to adjust the stepper task rate to e.g. 1ms (see #288 for reference)
+
 0.31.2:
 - Move constants out of PoorManFloat.h and autogenerate these
 - Fix pmfl constant used by SAM Due aka 21MHz

library.properties

@@ -1,5 +1,5 @@
 name=FastAccelStepper
-version=0.31.2
+version=0.31.3
 license=MIT
 author=Jochen Kiemes <[email protected]>
 maintainer=Jochen Kiemes <[email protected]>

src/FastAccelStepper.h

@@ -94,6 +94,34 @@ class FastAccelStepperEngine {
                                         uint8_t driver_type = DRIVER_DONT_CARE);
 #endif
 
+#if defined(SUPPORT_TASK_RATE_CHANGE)
+  // For e.g. esp32 the repetition rate of the stepper task can be changed.
+  // The default delay is 4ms.
+  //
+  // The steppertask is looping with:
+  //       manageSteppers()
+  //       wdt_reset()
+  //       delay()
+  //
+  // The actual repetition rate of the stepper task is delay + execution time of manageSteppers()
+  //
+  // This function is primary of interest in conjunction with setForwardPlanningTimeInMs().
+  // If the delay is larger then forward planning time, then the stepper queue will always
+  // run out of commands, which lead to a sudden stop of the motor. If the delay is 0,
+  // then the stepper task will constantly looping, which may lead to the task blocking other
+  // tasks. Consequently, this function is intended for advanced users.
+  //
+  // There is not planned to test this functionality, because automatic testing is only
+  // available for avr devices and those continue to use fixed 4ms rate.
+  //
+  // Please be aware, that the configured tick rate aka portTICK_PERIOD_MS is relevant.
+  // Apparently, arduino-esp32 has FreeRTOS configured to have a tick-rate of 1000Hz
+  inline void task_rate(uint8_t delay_ms) {
+    _delay_ms = delay_ms;
+  };
+  uint8_t _delay_ms;
+#endif
+
   // Comments to valid pins:
   //
   // clang-format off

src/StepperISR_esp32.cpp

@@ -106,16 +106,15 @@ int8_t StepperQueue::queueNumForStepPin(uint8_t step_pin) { return -1; }
 //*************************************************************************************************
 void StepperTask(void *parameter) {
   FastAccelStepperEngine *engine = (FastAccelStepperEngine *)parameter;
-  const TickType_t delay_4ms =
-      (DELAY_MS_BASE + portTICK_PERIOD_MS - 1) / portTICK_PERIOD_MS;
   while (true) {
     engine->manageSteppers();
 #if ESP_IDF_VERSION_MAJOR == 4
     // not clear, if the wdt reset is needed. With idf-version 5, the reset
     // causes an issue.
     esp_task_wdt_reset();
 #endif
-    vTaskDelay(delay_4ms);
+    const TickType_t delay_time = (engine->_delay_ms + portTICK_PERIOD_MS - 1) / portTICK_PERIOD_MS;
+    vTaskDelay(delay_time);
   }
 }
 
@@ -131,6 +130,7 @@ void fas_init_engine(FastAccelStepperEngine *engine, uint8_t cpu_core) {
 #define STACK_SIZE 3000
 #define PRIORITY (configMAX_PRIORITIES - 1)
 #endif
+  engine->_delay_ms = DELAY_MS_BASE;
   if (cpu_core > 1) {
     xTaskCreate(StepperTask, "StepperTask", STACK_SIZE, engine, PRIORITY, NULL);
   } else {

src/fas_arch/common_esp32.h

@@ -45,6 +45,9 @@
 // have more than one core
 #define SUPPORT_CPU_AFFINITY
 
+// have adjustable stepper task rate
+#define SUPPORT_TASK_RATE_CHANGE
+
 #define LL_TOGGLE_PIN(dirPin)                  \
   gpio_ll_set_level(&GPIO, (gpio_num_t)dirPin, \
                     gpio_ll_get_level(&GPIO, (gpio_num_t)dirPin) ^ 1)