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

The communication parameters


Before starting to use a serial port in order to communicate with an external serial device, we must know the communication parameters it uses, that is, which are the specific configuration settings of the serial data we wish to transfer. So, we must know the speed, data-bits, parity, and stop-bits settings.

For the speed, only fixed values are typically allowed. In fact, we must choose from 75, 110, 300, 1200, 2400, 4800, 9600, 19200, 38400, 57600, and 115200 bit/s.

Tip

In reality, other speed settings can be used. You should carefully read the datasheet of the serial device to check the allowed baud rates.

Regarding data bits, the usual setting is 8 (that is, 8 bits are used to transfer the information) even if we can choose from 6 (rarely used), 7 (for ASCII), 8, or 9 (rarely used). In the upcoming examples, I'm going to use the value 8 for this setting.

The parity bits and stop bits are deeply related to the serial communication protocol that we have not exposed...