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

Getting access to SPI devices


Now, we are ready to manage real SPI devices. We can find tons of supported devices in Linux's tree that are usually grouped according to their specific operations in complete analogy to the I2C case.

In the next section, we will see several different kinds of devices all connected to the main CPU through the SPI bus. Also, we will use different embedded kits to test them, but as said earlier, every command can be easily repeated on every GNU-/Linux-based boards with a similar configuration.

LCD display

As the first example, we will use the following tiny LCD display, which can be used in simple applications because it's cheap and well supported by BeagleBone Black's kernel:

Note

The device can be purchased at http://www.cosino.io/product/color-tft-lcd-1-8-160x128 or by surfing the Internet. The LCD is based on the chip ST7735R, which has its datasheet at:  https://www.adafruit.com/datasheets/ST7735R_V0.2.pdf.

First of all, we must do the following electrical...