Task Idle Hook Revision as of 10:38, 28 June 2016 by Explorer (Talk | contribs) (diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)

In the earlier example, we created 2 high priority task and an Idle task.
In this tutorial, we will see how to use the scheduler Idle task to run the user function.

What is Idle Task

Idle task is automatically created when the scheduler starts.
When no tasks are available for the CPU then this task will run.
When a task is deleted, the memory used by it will not be free immediately. This will be done in the idle task.

Using Idle Task Hook

To use the Idle task, configUSE_IDLE_HOOK should be set to 1.
In Arduino the loop() function is hooked to freeRtos Idle Task and will be called whenever the scheduler runs its Idle Task.

Example

	/***************************************************************************************************
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	****************************************************************************************************
	* File: 02-TaskIdleHook
	* Version: 15.0
	* Author: ExploreEmbedded
	* Website: http://www.exploreembedded.com/wiki
	* Description: File contains the free rtos example to demonstarte the task switching along with task hook function.
	This code has been developed and tested on ExploreEmbedded boards.
	We strongly believe that the library works on any of development boards for respective controllers.
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	RELATED TO UPDATES.
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	and without fee is hereby granted, provided that this copyright notices appear in all copies
	and that both those copyright notices and this permission notice appear in supporting documentation.
	**************************************************************************************************/
	#include <Arduino_FreeRTOS.h>
	void setup()
	{
	Serial.begin(9600);
	Serial.println(F("In Setup function"));
	/* Create two tasks with priorities 1 and 2.
	* Enable the Idle Task Hook by setting configUSE_IDLE_HOOK to 1, by this the loop function can be used as Idle task*/
	xTaskCreate(MyTask1, "Task1", 100, NULL, 1, NULL);
	xTaskCreate(MyTask2, "Task2", 100, NULL, 2, NULL);
	}
	void loop()
	{
	// Hooked to IDle task, it will run whenever CPU is idle
	Serial.println(F("Loop function"));
	delay(50);
	}
	/* Task1 with priority 1 */
	static void MyTask1(void* pvParameters)
	{
	while(1)
	{
	Serial.println(F("Task1"));
	vTaskDelay(100/portTICK_PERIOD_MS);
	}
	}
	/* Task2 with priority 2 */
	static void MyTask2(void* pvParameters)
	{
	while(1)
	{
	Serial.println(F("Task2"));
	vTaskDelay(150/portTICK_PERIOD_MS);
	}
	}

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