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

Static and dynamic allocation of FreeRTOS primitives

Details on the mechanics of creating tasks were covered in Chapter 7, The FreeRTOS Scheduler. Here, we will only focus on the differences in where the memory is coming from and what its lifetime is. This will help illuminate the implications of choosing different allocation schemes.

Memory for tasks can either be allocated dynamically or statically. Dynamic allocation allows the memory used by the task to be returned by calling vTaskDelete() if the task no longer needs to run (see Chapter 7, The FreeRTOS Scheduler, for details). Dynamic allocation can occur at any point in the program, whereas static allocation occurs before the program starts. The static variants of FreeRTOS API calls follow the same initialization scheme—the standard calls use dynamic allocation (pulling memory from the FreeRTOS heap). All FreeRTOS...