Task handle usage in FreeRTOS - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a Task Handle in FreeRTOS?

A Task Handle is a reference or pointer to a task in FreeRTOS. It allows you to identify and manage the task after it is created, such as suspending, resuming, or deleting the task.

beginner

How do you create a task and get its handle in FreeRTOS?

You use the xTaskCreate() function, which has a parameter to store the task handle. For example: <br>

TaskHandle_t xHandle = NULL;
xTaskCreate(TaskFunction, "TaskName", stackSize, NULL, priority, &xHandle);

beginner

Why is it useful to keep a Task Handle after creating a task?

Keeping a Task Handle lets you control the task later. You can suspend, resume, delete, or change its priority by passing the handle to FreeRTOS API functions.

intermediate

How do you suspend and resume a task using its handle?

Use vTaskSuspend() to pause the task and vTaskResume() to continue it. Both functions take the Task Handle as an argument. For example:<br>

vTaskSuspend(xHandle);
vTaskResume(xHandle);

intermediate

What happens if you pass NULL as the Task Handle to vTaskSuspend() or vTaskResume()?

Passing NULL means the function will act on the current running task. So, vTaskSuspend(NULL) suspends the task that calls it.

What type is used to store a task handle in FreeRTOS?

A TaskHandle_t

B int

C void*

D TaskID

TaskHandle_t is the FreeRTOS type specifically for task handles.

Which function creates a task and can return its handle?

A vTaskStartScheduler()

B xQueueCreate()

C xTaskCreate()

D vTaskDelete()

xTaskCreate() creates a task and can provide its handle via a pointer parameter.

How do you suspend a task using its handle?

A xTaskCreate(handle)

B vTaskDelete(handle)

C vTaskResume(handle)

D vTaskSuspend(handle)

vTaskSuspend() pauses the task identified by the handle.

What does passing NULL to vTaskResume() do?

A Resumes all tasks

B Resumes the current running task

C Causes an error

D Resumes the idle task

Passing NULL means the function acts on the current task.

Why should you store a task handle when creating a task?

A To control the task later (suspend, resume, delete)

B To increase the task's stack size

C To change the task's name

D To start the scheduler

The handle lets you manage the task after creation.

Explain what a Task Handle is and how it is used in FreeRTOS.

Think about how you keep a reference to a task to control it later.

Describe the steps to create a task and then suspend and resume it using its handle.

Focus on the functions and the role of the handle.