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

Reusing a queue definition for a new target

On the surface, it might be hard to appreciate just how flexible a setup such as this one is. On the command-entry side, we have the ability to acquire commands from anything, not just the binary framed protocol over USB. Since the data being placed into the queue was abstracted to not include any protocol-specific information, the underlying protocol could change without requiring any changes downstream.

Let's take a look at a few examples:

  • We could write a different routine for parsing incoming data that uses a comma-separated ASCII string, where duty cycles are represented by percentages between 0 and 100 and a string-based enumeration, terminated by a new line: BLINK, 20, 30, 100\n. This would result in the following value being placed in ledCmdQueue:
LedCmd cmd = {.cmdNum=3, .red=20, .blue=30, .green=100};