You're reading from Hands-On RTOS with Microcontrollers Create high-performance, real-time embedded systems using FreeRTOS, STM32 MCUs, and SEGGER debug tools

Product type Paperback

Published in Sep 2025

Publisher Packt

ISBN-13 9781803237725

Length 570 pages

Edition 2nd Edition

Languages

Concepts

Operating Systems

Authors (2):

Jim Yuill

Penn Linder

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Table of Contents (27) Chapters

Preface

1. Part 1: Introduction to RTOSes, the Dev-Board, and Tools

2. Introducing Real-Time Systems FREE CHAPTER

3. Introducing the Development Board

4. Introducing the Development-Tools

5. Understanding Super-Loops

6. Implementing the Super-Loop

7. Part 2: The FreeRTOS Scheduler, Tasks, and Primary APIs

8. Understanding RTOS Tasks

9. Running the FreeRTOS Scheduler

10. Protecting Data and Synchronizing Tasks

11. Intertask Communication

12. Part 3: Using FreeRTOS to Build Systems

13. Drivers and ISRs

14. More Efficient Drivers and ISRs

15. Sharing Hardware Peripherals among Tasks

16. Creating Loose Coupling with Queues

17. Part 4: System Design and Troubleshooting

18. FreeRTOS Memory Management

19. Multi-Processor and Multi-Core Systems

20. Troubleshooting Tips and Next Steps

21. Part 5: Reference Information and FreeRTOS Installation

22. Other Books You May Enjoy

23. Index

Appendix A: Tools Quick-Reference

1. Appendix B: Reference Information

2. Appendix C: Creating FreeRTOS Projects, and Installing FreeRTOS

Task notifications

Queues are an excellent workhorse of an RTOS because of their flexibility. Sometimes, all of this flexibility isn’t needed and we’d prefer a more lightweight alternative for tasks to communicate with each other. FreeRTOS provides this with its task notifications feature.

A task notification has two main components: the notification itself, and a 32-bit value. A task can send a notification to another task. Conversely, a task can read a notification that has been sent to it. Each task has a notification state, which can be pending or not-pending. Each task also has a notification value, which is a 32-bit unsigned integer. The notification value is stored in the task’s Task Control Block (TCB). The TCB is defined in Middleware\Third_Party\FreeRTOS\Source\tasks.c.

When a notification is sent to a task, its notification state is set to pending. When a task reads its notification value, its notification state is set to not-pending. When a...