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

Designing low-power embedded applications


In this section, a few design patterns are proposed to achieve a better energy profile on the target device, by evaluating the power demand of all the components and the states of the system we are about to design. Once we know how to measure the values in the target, and the details about the low-power mode in the selected architecture and microprocessor family, the application can be programmed keeping other parameters in mind, such as the energy efficiency of the software we are writing.

Replacing busy loops with sleep mode

The reason busy loops are very popular among hobbyists is that they are so easy to implement. Suppose that the system needs to wait for a digital input to switch to a low-logic state, and this input is mapped to a certain GPIO. This can be easily done with the following one-liner:

while((GPIOX_IDR & (1 << INPUT_PINX)) != 0)
    ;

While this is perfectly working as expected, it will force the CPU in a loop of fetch-decode...