Book Image

Hands-On RTOS with Microcontrollers

By : Brian Amos
Book Image

Hands-On RTOS with Microcontrollers

By: Brian Amos

Overview of this book

A real-time operating system (RTOS) is used to develop systems that respond to events within strict timelines. Real-time embedded systems have applications in various industries, from automotive and aerospace through to laboratory test equipment and consumer electronics. These systems provide consistent and reliable timing and are designed to run without intervention for years. This microcontrollers book starts by introducing you to the concept of RTOS and compares some other alternative methods for achieving real-time performance. Once you've understood the fundamentals, such as tasks, queues, mutexes, and semaphores, you'll learn what to look for when selecting a microcontroller and development environment. By working through examples that use an STM32F7 Nucleo board, the STM32CubeIDE, and SEGGER debug tools, including SEGGER J-Link, Ozone, and SystemView, you'll gain an understanding of preemptive scheduling policies and task communication. The book will then help you develop highly efficient low-level drivers and analyze their real-time performance and CPU utilization. Finally, you'll cover tips for troubleshooting and be able to take your new-found skills to the next level. By the end of this book, you'll have built on your embedded system skills and will be able to create real-time systems using microcontrollers and FreeRTOS.
Table of Contents (24 chapters)
Section 1: Introduction and RTOS Concepts
Section 2: Toolchain Setup
Section 3: RTOS Application Examples
Section 4: Advanced RTOS Techniques


The Portable Operating System Interface (POSIX) was developed to provide a unified interface for interacting with operating systems, making code more portable between systems.

At the time of writing, FreeRTOS has a beta implementation for a subset of the POSIX API. The POSIX headers that have been (partly) ported are listed here:

  • errno.h
  • fcntl.h
  • mqueue.h
  • mqueue.h
  • sched.h
  • semaphore.h
  • signal.h
  • sys/types.h
  • time.h
  • unistd.h

Generally speaking, threading, queues, mutexes, semaphores, timers, sleep, and some clock functions are implemented by the port. This feature set sometimes covers enough of a real-world use case to enable porting applications that have been written to be POSIX-compliant to an MCU supporting FreeRTOS. Keep in mind that FreeRTOS does not supply a filesystem on its own without additional middleware, so any application requiring filesystem access...