Task function signature in FreeRTOS - Step-by-Step Execution

Concept Flow - Task function signature

Start Task Function

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Function receives void* parameter

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Function runs infinite loop

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Task does work inside loop

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Optionally uses vTaskDelay or other FreeRTOS APIs

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Loop repeats forever

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Task never returns

A FreeRTOS task function starts with a void pointer parameter and runs an infinite loop doing its work without returning.

Execution Sample

FreeRTOS

void TaskFunction(void *pvParameters) {
    for(;;) {
        // Task code here
        vTaskDelay(1000 / portTICK_PERIOD_MS);
    }
}

This task function runs forever, delaying 1 second each loop iteration.

Execution Table

Step	Action	Parameter (pvParameters)	Loop Condition	Task Behavior
1	Task starts	Pointer to parameters	Enter infinite loop	Begin task work
2	Inside loop iteration 1	Pointer unchanged	Loop continues	Execute task code, call vTaskDelay(1000 / portTICK_PERIOD_MS)
3	Inside loop iteration 2	Pointer unchanged	Loop continues	Execute task code, call vTaskDelay(1000 / portTICK_PERIOD_MS)
4	Inside loop iteration 3	Pointer unchanged	Loop continues	Execute task code, call vTaskDelay(1000 / portTICK_PERIOD_MS)
...	Loop repeats forever	Pointer unchanged	Loop continues	Task keeps running, never returns

💡 Task function never exits; it runs an infinite loop to keep the task alive.

Variable Tracker

Variable	Start	After 1	After 2	After 3	Final
pvParameters	Pointer to input data	Same pointer	Same pointer	Same pointer	Same pointer

Key Moments - 3 Insights

Why does the task function use an infinite loop?

Because FreeRTOS tasks must keep running to stay alive; the infinite loop ensures the task does not return and get deleted (see execution_table rows 2-5).

What is the purpose of the void* parameter?

It allows passing any data to the task when created; the pointer stays the same throughout the task execution (see variable_tracker).

Can the task function return to end the task?

No, returning would delete the task; tasks should run forever or call vTaskDelete explicitly if they want to end.

Visual Quiz - 3 Questions

Look at the execution_table, what happens to pvParameters after the first loop iteration?

A It stays the same pointer

B It becomes NULL

C It changes to a new pointer

D It is freed automatically

💡 Hint

Check the 'Parameter (pvParameters)' column in execution_table rows 2 and 3.

At which step does the task function exit the infinite loop?

A Step 1

B Step 3

C It never exits

D After the third iteration

💡 Hint

See the 'Loop Condition' column in execution_table; the loop continues forever.

If the infinite loop was removed, what would happen to the task?

A The task would run forever anyway

B The task would run once and then delete itself

C The task would never start

D The task would crash the system

💡 Hint

Refer to key_moments about why the infinite loop is needed to keep the task alive.

Concept Snapshot

FreeRTOS task functions have this signature:
void TaskFunction(void *pvParameters)
{
    for(;;) {
        // task code
        vTaskDelay(...);
    }
}
They receive a void pointer parameter and run an infinite loop to stay alive.

Full Transcript

A FreeRTOS task function must have the signature void TaskFunction(void *pvParameters). It receives a pointer to any data passed when the task is created. The function runs an infinite loop to keep the task alive and perform its work repeatedly. Inside the loop, it can call FreeRTOS APIs like vTaskDelay to wait or yield. The task function never returns; returning would delete the task. The parameter pointer remains unchanged during execution. This pattern ensures the task runs continuously until explicitly deleted.