Book Image

The Insider's Guide to Arm Cortex-M Development

By : Zachary Lasiuk, Pareena Verma, Jason Andrews
Book Image

The Insider's Guide to Arm Cortex-M Development

By: Zachary Lasiuk, Pareena Verma, Jason Andrews

Overview of this book

Cortex-M has been around since 2004, so why a new book now? With new microcontrollers based on the Cortex-M55 and Cortex-M85 being introduced this year, Cortex-M continues to expand. New software concepts, such as standardized software reuse, have emerged alongside new topics including security and machine learning. Development methodologies have also significantly advanced, with more embedded development taking place in the cloud and increased levels of automation. Due to these advances, a single engineer can no longer understand an entire project and requires new skills to be successful. This book provides a unique view of how to navigate and apply the latest concepts in microcontroller development. The book is split into two parts. First, you’ll be guided through how to select the ideal set of hardware, software, and tools for your specific project. Next, you’ll explore how to implement essential topics for modern embedded developers. Throughout the book, there are examples for you to learn by working with real Cortex-M devices with all software available on GitHub. You will gain experience with the small Cortex-M0+, the powerful Cortex-M55, and more Cortex-M processors. By the end of this book, you’ll be able to practically apply modern Cortex-M software development concepts.
Table of Contents (15 chapters)
Part 1: Get Set Up
Part 2: Sharpen Your Skills

Example 2 – TF-M

As noted previously, TF-M is a reference implementation of PSA for Cortex-M-based platforms. TF-M implements PSA developer APIs and has initially been targeted to Armv8-M architecture cores. It is reliant on the isolation boundary between the Secure Processing Environment (SPE) and Non-Secure Processing Environment (NSPE) that we covered in the previous example. It can be broadly broken down into three components.

Let’s review each component in detail:

  • Secure boot: TF-M software needs a secure bootloader that authenticates the integrity of the runtime images. This helps achieve Security Goal 4 regarding secure boot. TF-M currently uses a two-stage secure bootloader that validates that the images are from a trustworthy source and only then passes the right of execution to them. This implies all images in TF-M should be hashed and digitally signed for authentication purposes.

TF-M uses MCUBoot as the secure bootloader. MCUBoot is open...