Book Image

Embedded Systems Architecture

By : Daniele Lacamera
Book Image

Embedded Systems Architecture

By: Daniele Lacamera

Overview of this book

Embedded systems are self-contained devices with a dedicated purpose. We come across a variety of fields of applications for embedded systems in industries such as automotive, telecommunications, healthcare and consumer electronics, just to name a few. Embedded Systems Architecture begins with a bird's eye view of embedded development and how it differs from the other systems that you may be familiar with. You will first be guided to set up an optimal development environment, then move on to software tools and methodologies to improve the work flow. You will explore the boot-up mechanisms and the memory management strategies typical of a real-time embedded system. Through the analysis of the programming interface of the reference microcontroller, you'll look at the implementation of the features and the device drivers. Next, you'll learn about the techniques used to reduce power consumption. Then you will be introduced to the technologies, protocols and security aspects related to integrating the system into IoT solutions. By the end of the book, you will have explored various aspects of embedded architecture, including task synchronization in a multi-threading environment, and the safety models adopted by modern real-time operating systems.
Table of Contents (18 chapters)
Title Page
Copyright and Credits
Packt Upsell
Contributors
Preface
Index

The memory protection unit


In a system without virtual address mapping, it is harder to create a separation among sections that can be accessed by the software at runtime. The memory protection unit, often referred to as the MPU, is an optional component present in many ARM-based microcontrollers. The MPU is used to separate sections in memory by setting local permissions and attributes. This mechanism has several uses in real-life scenarios, such as preventing access to the memory when the CPU is running in user mode, or preventing fetching code to execute from writable locations in RAM. When the MPU is enabled, it enforces the rules by triggering a memory exception interrupt when those are violated.

While commonly used by operating systems to create process stack separation and enforce privileged access to system memory, the MPU can be useful in a number of other cases, including bare-metal applications.

MPU configuration registers

In Cortex-M, the control block region related to MPU configuration...