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

Video in Linux


In a GNU/Linux-based system, all video devices are managed by a standard API called Video4Linux (Video for Linux), which is a collection of device drivers to support real-time video capture. It supports many USB webcams, TV tuners, and similar devices in such a way that they have a common interface so that users can get access to to the underlying hardware in the same manner independently and programmers can easily add video support to their applications. The Video4Linux (V4L2) API is currently in its second version, which can be referred as Video4Linux2. Using the name Video4Linux only is not erroneous since the first release of the API was dropped several years ago from the kernel main line.

In a GNU/Linux-based system, each Video4Linux device appears in the system as a /dev/video0, /dev/video1 file. For example, to our BeagleBone Black, we have connected a webcam, and the video file we get is as follows:

root@bbb:~# ls -l /dev/video*
crw-rw---- 1 root video 81, 0 Oct 10...