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

Using a memory protection unit (MPU)

A memory protection unit (MPU) continuously monitors memory access at a hardware level to make absolutely certain that only legal memory accesses are occurring; otherwise, an interrupt is raised and immediate action can be taken. This allows many common errors (which might otherwise go unnoticed for a period of time) to be immediately detected.

Problems like stack overflows that make a stack flow into the memory space reserved for another task are immediately caught when using an MPU, even if they can't be detected by vApplicationStackOverflowHook. Buffer overflows and pointer errors are also stopped dead in their tracks when an MPU is utilized, which makes for a more robust application.

The STM32F767 MCU includes an MPU. In order to make use of it, the MPU-enabled port must be used: GCC\ARM_CM4_MPU. This way, restricted tasks can be created...