Why tasks are the building blocks in FreeRTOS - See It in Action

Why tasks are the building blocks

📖 Scenario: You are working on a small embedded system project using FreeRTOS. You want to understand how tasks work as the main building blocks to run different parts of your program independently.

🎯 Goal: Build a simple FreeRTOS program that creates two tasks. Each task will print a message to show how tasks run separately and repeatedly.

📋 What You'll Learn

Create two tasks with specific names

Use the FreeRTOS API to create tasks

Each task should print a unique message

Use a delay to allow task switching

Print output to show tasks running independently

💡 Why This Matters

🌍 Real World

Embedded systems often need to run multiple functions at once, like reading sensors and controlling motors. Tasks let you organize these functions clearly.

💼 Career

Understanding tasks is essential for embedded software developers working with real-time operating systems like FreeRTOS.

1

Create two task functions

Write two functions called Task1 and Task2 that take a void *pvParameters argument and run an infinite loop. Inside each loop, add a comment // Task running to indicate where code will go.

FreeRTOS

void Task1(void *pvParameters) {
    // Task running
}

void Task2(void *pvParameters) {
    // Task running
}

Need a hint?

Each task function must have an infinite loop to keep running.

2

Create task handles and stack size

Declare two variables called xTaskHandle1 and xTaskHandle2 of type TaskHandle_t. Also, create a constant STACK_SIZE with value configMINIMAL_STACK_SIZE.

FreeRTOS

void Task1(void *pvParameters) {
    for (;;) {
        // Task running
    }
}

void Task2(void *pvParameters) {
    for (;;) {
        // Task running
    }
}

// Declare task handles and stack size
// Your code here

Need a hint?

Task handles are used to manage tasks after creation. Stack size defines memory for each task.

3

Create the two tasks in main

In the main function, use xTaskCreate to create Task1 and Task2. Use STACK_SIZE for stack size, NULL for parameters, priority 1, and store handles in xTaskHandle1 and xTaskHandle2. Then start the scheduler with vTaskStartScheduler().

FreeRTOS

void Task1(void *pvParameters) {
    for (;;) {
        // Task running
    }
}

void Task2(void *pvParameters) {
    for (;;) {
        // Task running
    }
}

TaskHandle_t xTaskHandle1;
TaskHandle_t xTaskHandle2;
const uint16_t STACK_SIZE = configMINIMAL_STACK_SIZE;

int main(void) {
    // Create Task1 and Task2
    // Start scheduler
    // Your code here
}

Need a hint?

Use xTaskCreate to make tasks and vTaskStartScheduler to run them.

4

Add print statements and delay inside tasks

Inside the infinite loop of Task1, add printf("Task1 is running\n") and vTaskDelay(pdMS_TO_TICKS(1000)). Inside Task2, add printf("Task2 is running\n") and vTaskDelay(pdMS_TO_TICKS(1500)). This will show each task running independently with delays.

FreeRTOS

void Task1(void *pvParameters) {
    for (;;) {
        // Print message and delay
        // Your code here
    }
}

void Task2(void *pvParameters) {
    for (;;) {
        // Print message and delay
        // Your code here
    }
}

TaskHandle_t xTaskHandle1;
TaskHandle_t xTaskHandle2;
const uint16_t STACK_SIZE = configMINIMAL_STACK_SIZE;

int main(void) {
    xTaskCreate(Task1, "Task1", STACK_SIZE, NULL, 1, &xTaskHandle1);
    xTaskCreate(Task2, "Task2", STACK_SIZE, NULL, 1, &xTaskHandle2);
    vTaskStartScheduler();
    for(;;); // Should never reach here
}

Need a hint?

Use printf to show task messages and vTaskDelay to pause each task.