Book Image

Embedded Systems Architecture - Second Edition

By : Daniele Lacamera
5 (1)
Book Image

Embedded Systems Architecture - Second Edition

5 (1)
By: Daniele Lacamera

Overview of this book

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. This book will help you get the hang of the internal working of various components in real-world systems. You’ll start by setting up a development environment and then move on to the core system architectural concepts, exploring system designs, boot-up mechanisms, and memory management. As you progress through the topics, you’ll explore the programming interface and device drivers to establish communication via TCP/IP and take measures to increase the security of IoT solutions. Finally, you’ll be introduced to multithreaded operating systems through the development of a scheduler and the use of hardware-assisted trusted execution mechanisms. With the help of this book, you will gain the confidence to work with embedded systems at an architectural level and become familiar with various aspects of embedded software development on microcontrollers—such as memory management, multithreading, and RTOS—an approach oriented to memory isolation.
Table of Contents (18 chapters)
Part 1 – Introduction to Embedded Systems Development
Part 2 – Core System Architecture
Part 3 – Device Drivers and Communication Interfaces
Part 4 – Multithreading

The watchdog

A common feature in many microcontrollers is the presence of a watchdog timer. A watchdog ensures that the system is not stuck within an endless loop or any other blocking situation within the code. This is particularly useful in bare-metal applications that rely on an event-driven loop, where calls are required not to block, and to return to the main event loop within the allowed amount of time.

The watchdog must be seen as the very last resort to recover an unresponsive system, by triggering a forced reboot regardless of the current state of execution in the CPU.

The reference platform provides one independent watchdog timer, with a counter similar to those of the generic timers, with a 12-bit granularity and a prescaler factor. The prescaler of the watchdog, however, is expressed in multiples of 2 and has a range between 4 (represented by the value 0) and 256 (value 6).

The clock source is connected to a lower-speed oscillator, through an independent branch...