Learn FREERTOS with Real Code Examples

FreeRTOS allows multiple tasks (threads) to run seemingly simultaneously on microcontrollers.

Provides task scheduling with priorities, preemption, and time slicing.

Supports inter-task communication using queues, semaphores, and mutexes.

Highly portable across 8/16/32-bit MCUs and architectures like ARM, AVR, PIC, and RISC-V.

Used widely in industrial, IoT, automotive, and consumer embedded systems.

Tasks (threads)

Queues for message passing

Semaphores and mutexes

Event groups for synchronization

Tick-based software timers

Task - independent unit of execution

Queue - thread-safe message passing

Semaphore - signaling between tasks

Mutex - mutual exclusion for shared resources

Tick - periodic timer driving scheduling

FreeRTOS source folder (tasks, queue, timers)

Application C source files

Board support package (BSP) and driver files

FreeRTOSConfig.h

Makefile or IDE project configuration

Configure FreeRTOS kernel

Create tasks using xTaskCreate

Set up queues, semaphores, or mutexes

Start scheduler with vTaskStartScheduler

Test tasks and inter-task communication

Beginner: blink LED task with delay

Intermediate: multiple tasks with queues

Advanced: ISR + tasks + priority management

Expert: tickless low-power mode and dynamic memory

Architect: complex multitasking IoT device

FreeRTOS vs Zephyr: FreeRTOS simpler, Zephyr more full-featured

FreeRTOS vs ChibiOS: FreeRTOS more widely used, ChibiOS faster kernel

FreeRTOS vs bare-metal: RTOS adds multitasking & scheduling

FreeRTOS vs Linux RT: FreeRTOS lighter, Linux richer OS

FreeRTOS vs ThreadX: FreeRTOS open-source, ThreadX commercial with safety certifications

2003 - FreeRTOS created by Richard Barry

2006 - Kernel modularization

2012 - Tickless idle mode introduced

2015 - Amazon FreeRTOS announced

2018 - FreeRTOS+TCP and +FAT improvements

2020 - ARM Cortex-M MPU support enhancements

2022 - Latest FreeRTOS kernel updates

2024 - Expanded support for RISC-V and low-power MCUs

2025 - Continued integration with AWS IoT services

Task - independent thread

Queue - message passing structure

Semaphore - signaling mechanism

Mutex - mutual exclusion

Tick - system timer interrupt for scheduling