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

RTOS tasks versus super loops – pros and cons

Super loops are great for simple systems with limited responsibilities. If a system is simple enough, they can provide very low jitter in response to an event, but only if the loop is tight enough. As a system grows more complex and acquires more responsibility, polling rates decrease. This decreased polling rate causes much larger jitter in response to events. Interrupts can be introduced into the system to combat the increased jitter. As a super loop-based system becomes more complex, it becomes harder to track and guarantee responsiveness to events.

An RTOS becomes very valuable with more complex systems that have not only time-consuming tasks, but also require good responsiveness to external events. With an RTOS, an increase in system complexity, ROM, RAM, and initial setup time is the trade-off for a more easily understood...