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

The watchdog

Another 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 the 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 of the...