Book Image

GNU/Linux Rapid Embedded Programming

By : Rodolfo Giometti
Book Image

GNU/Linux Rapid Embedded Programming

By: Rodolfo Giometti

Overview of this book

Embedded computers have become very complex in the last few years and developers need to easily manage them by focusing on how to solve a problem without wasting time in finding supported peripherals or learning how to manage them. The main challenge with experienced embedded programmers and engineers is really how long it takes to turn an idea into reality, and we show you exactly how to do it. This book shows how to interact with external environments through specific peripherals used in the industry. We will use the latest Linux kernel release 4.4.x and Debian/Ubuntu distributions (with embedded distributions like OpenWrt and Yocto). The book will present popular boards in the industry that are user-friendly to base the rest of the projects on - BeagleBone Black, SAMA5D3 Xplained, Wandboard and system-on-chip manufacturers. Readers will be able to take their first steps in programming the embedded platforms, using C, Bash, and Python/PHP languages in order to get access to the external peripherals. More about using and programming device driver and accessing the peripherals will be covered to lay a strong foundation. The readers will learn how to read/write data from/to the external environment by using both C programs or a scripting language (Bash/PHP/Python) and how to configure a device driver for a specific hardware. After finishing this book, the readers will be able to gain a good knowledge level and understanding of writing, configuring, and managing drivers, controlling and monitoring applications with the help of efficient/quick programming and will be able to apply these skills into real-world projects.
Table of Contents (26 chapters)
GNU/Linux Rapid Embedded Programming
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

What is the CAN bus?


The Controller Area Network (CAN) bus is a half-duplex, multi-master, multi-slave, asynchronous serial data bus designed for connecting Electronic Control Units (ECU), also known as nodes, using two wires bus. From the electrical point of view, data is sent on these wires in a differential mode (as the USB bus does), so we can send the information across long distances with a large quantities of connected devices.

Each node is able to send and receive messages, but not simultaneously, and a message (or frame) consists primarily of the identifier (or ID, which represents the priority of the message) and up to 8 (or 64, in the case of extended messages) data bytes followed by some acknowledge and other control data.

To do its job, each node requires:

  • A CPU (microprocessor or host processor), which decides what received messages mean and which messages want to transmit.

  • A CAN controller, which is often an integral part of the CPU (but it can be added as an external peripheral...