Idle task and idle hook in FreeRTOS - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define the FreeRTOS idle hook function.

FreeRTOS

void vApplicationIdleHook(void) {
    [1];
}

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Aprintf("Idle\n")

BvTaskDelay(100)

CtaskYIELD()

DxTaskCreate()

Attempts:

3 left

💡 Hint

Common Mistakes

Using vTaskDelay() inside the idle hook causes unexpected delays.

Calling xTaskCreate() inside the idle hook is incorrect.

The idle hook function often calls taskYIELD() to allow other tasks to run.

2fill in blank

medium

Complete the code to enable the idle hook in FreeRTOSConfig.h.

FreeRTOS

#define configUSE_IDLE_HOOK [1]

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A1

Btrue

C2

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Using 0 disables the idle hook.

Using 'true' instead of 1 may cause configuration errors.

Setting configUSE_IDLE_HOOK to 1 enables the idle hook function.

3fill in blank

hard

Fix the error in the idle hook function to prevent blocking calls.

FreeRTOS

void vApplicationIdleHook(void) {
    [1];
}

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AtaskYIELD()

Bwhile(1) {}

CvTaskSuspend(NULL)

DvTaskDelay(10)

Attempts:

3 left

💡 Hint

Common Mistakes

Using vTaskDelay() blocks the idle task and can cause system issues.

Infinite loops without yielding prevent other tasks from running.

The idle hook must not block. Using taskYIELD() allows other tasks to run without blocking.

4fill in blank

hard

Fill both blanks to create a dictionary comprehension that maps task names to their states if the task is running.

FreeRTOS

task_states = {task->pcTaskName: task->eCurrentState for task in [1] if task->eCurrentState [2] eRunning}

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ApxTaskGetSystemState()

BeSuspended

C==

D!=

Attempts:

3 left

💡 Hint

Common Mistakes

Using != eRunning selects non-running tasks.

Using eSuspended instead of a function causes errors.

Use pxTaskGetSystemState() to get tasks and == to check if the task is running.

5fill in blank

hard

Fill all three blanks to define an idle hook that toggles an LED when the system is idle and yields control.

FreeRTOS

void vApplicationIdleHook(void) {
    [1]();
    [2] = ![3];
    taskYIELD();
}

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AToggleLED

BledState

DvTaskDelay

Attempts:

3 left

💡 Hint

Common Mistakes

Using vTaskDelay() inside idle hook causes blocking.

Not toggling the LED state variable causes no visible change.

The idle hook toggles the LED by calling ToggleLED() and flipping ledState, then yields.