Welcome to Real-Time Bluetooth Networks – Shape the World. This book offers a format geared towards hands-on self-paced learning. The overarching goal is to give you the student an experience with real-time operating systems that is based on the design and development of a simplified RTOS that exercises all the fundamental concepts. To keep the discourse grounded in practice we have refrained from going too deep into any one topic. We believe this will equip the student with the knowledge necessary to explore more advanced topics on their own. In essence, we will teach you the skills of the trade, but mastery is the journey you will have to undertake on your own. An operating system (OS) is layer of software that sits on top of the hardware. It manages the hardware resources so that the applications have the illusion that they own the hardware all to themselves. A real-time system is one that not only gets the correct answer but gets the correct answer at the correct time. Design and development of an OS therefore requires both, understanding the underlying architecture in terms of the interface (instruction set architecture, ISA) it provides to the software, and organizing the software to exploit this interface and present it to user applications. The decisions made in effectively managing the underlying architecture becomes more crucial in real-time systems as the performance (specifically timing) demands go beyond simple logical correctness. The architecture we will focus on is the ARM ISA, which is a very popular architecture in the embedded device ecosystem where real-time systems proliferate. A quick introduction to the ISA will be followed by specifics of TI’s offering of this ISA as the Tiva and MSP432 Launchpad microcontroller. To make the development truly compelling we need a target application that has real-time constraints and multi-threading needs. To that end you will incrementally build a personal fitness device with Bluetooth connectivity. The Bluetooth connectivity will expose you to the evolving domain of Internet-of-things (IoT) where our personal fitness device running a custom RTOS will interact with a smartphone.