Exploring BeagleBone E-Book

Derek Molloy

• Herausgeber: John Wiley & Sons
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch
• Veröffentlichungsjahr: 2014

Seitenzahl: 847

Beschreibung

In-depth instruction and practical techniques for buildingwith the BeagleBone embedded Linux platform Exploring BeagleBone is a hands-on guide to bringinggadgets, gizmos, and robots to life using the popular BeagleBoneembedded Linux platform. Comprehensive content and deep detailprovide more than just a BeagleBone instructionmanual--you'll also learn the underlying engineeringtechniques that will allow you to create your own projects. Thebook begins with a foundational primer on essential skills, andthen gradually moves into communication, control, and advancedapplications using C/C++, allowing you to learn at your own pace.In addition, the book's companion website featuresinstructional videos, source code, discussion forums, and more, toensure that you have everything you need. The BeagleBone's small size, high performance, low cost,and extreme adaptability have made it a favorite developmentplatform, and the Linux software base allows for complex yetflexible functionality. The BeagleBone has applications in smartbuildings, robot control, environmental sensing, to name a few;and, expansion boards and peripherals dramatically increase thepossibilities. Exploring BeagleBone provides areader-friendly guide to the device, including a crash coursein computer engineering. While following step by step, you can: * Get up to speed on embedded Linux, electronics, andprogramming * Master interfacing electronic circuits, buses and modules, withpractical examples * Explore the Internet-connected BeagleBone and the BeagleBonewith a display * Apply the BeagleBone to sensing applications, including videoand sound * Explore the BeagleBone's Programmable Real-TimeControllers Hands-on learning helps ensure that your new skills stay withyou, allowing you to design with electronics, modules, orperipherals even beyond the BeagleBone. Insightful guidance andonline peer support help you transition from beginner to expert asyou master the techniques presented in Exploring BeagleBone,the practical handbook for the popular computing platform.

Leseprobe

Contents

Introduction

Why the BeagleBone Black?

How This Book Is Structured

Conventions Used in This Book

What You'll Need

Errata

Digital Content and Source Code

Part I BeagleBone Basics

Chapter 1 The BeagleBone Hardware

Introduction to the Platform

BeagleBone Documentation

The BeagleBone Hardware

BeagleBone Accessories

Capes

How to Destroy Your BeagleBone!

Summary

Support

Notes

Chapter 2 The BeagleBone Black Software

Linux on the BeagleBone

Communicating with the BBB

Controlling the BeagleBone

Node.js, Cloud9, and BoneScript

Summary

Further Reading

Chapter 3 Exploring Embedded Linux Systems

Embedded Linux Basics

Booting the BeagleBone

Managing Linux Systems

Git

Desktop Virtualization

Code for This Book

Summary

Further Reading

Chapter 4 Interfacing Electronics

Recommended Equipment

Basic Circuit Principles

Discrete Components

Logic Gates

Analog‐to‐Digital Conversion

Concluding Advice

Summary

Further Reading

Notes

Chapter 5 Practical BeagleBone Programming

Introduction

Scripting Languages

JavaScript and Java

C and C++ on the BeagleBone

C++ with Classes

Summary

Further Reading

Notes

Part II Interfacing, Controlling, and Communicating

Chapter 6 Interfacing to the BeagleBone Input/Outputs

General-Purpose Input/Outputs

The Linux Device Tree

Analog Inputs and Outputs

Advanced GPIO Topics

Summary

Further Reading

Notes

Chapter 7 Cross‐Compilation and the Eclipse IDE

Setting Up a Cross‐Compilation Toolchain

Cross‐Compilation with Third‐Party Libraries (Multiarch)

Installing a Change Root

Cross‐Compilation Using Eclipse

Building Debian for the BBB

Summary

Further Reading

Chapter 8 Interfacing to the BeagleBone Buses

Introduction to Bus Communication

I

2

C

SPI

UART

Logic‐Level Translation

Summary

Further Reading

Note

Chapter 9 Interacting with the Physical Environment

Interfacing to Actuators

Interfacing to Analog Sensors

Interfacing to Display Modules

Remote Control BeagleBone

Building Dynamic Linked Libraries

Summary

Further Reading

Notes

Part III Advanced BeagleBone Systems

Chapter 10 The Internet of Things

The Internet of Things (IoT)

More Sensors (Things!)

The BeagleBone as a Web Server

A C/C++ Web Client

The BeagleBone as a Web Sensor

The C++ Client/Server

Managing Remote IoT Devices

IoT Physical Networking

Summary

Further Reading

Notes

Chapter 11 BeagleBone with a Rich User Interface

Rich UI BBB Architectures

Rich UI Application Development

Qt Primer

Remote UI Application Development

Cross‐Compiling Qt Applications

Summary

Further Reading

Notes

Chapter 12 Images, Video, and Audio

Capturing Images and Video

Streaming Video

Image Processing and Computer Vision

BeagleBone Audio

Summary

Further Reading

Chapter 13 Real‐Time BeagleBone Interfacing

Real‐Time BeagleBone

The PRU‐ICSS Architecture

Getting Started with the PRU‐ICSS

The PRU‐ICSS in Detail

Applications of the PRU‐ICSS

Additional PRU‐ICSS Tools

Summary

Further Reading

Notes

Titlepage

Copyright

Dedication

About the Author

About the Technical Editors

Credits

Acknowledgments

End User License Agreement

List of Tables

Chapter 1

Table 1-1

Chapter 2

Table 2-1

Table 2-2

Table 2-3

Table 2-4

Table 2-5

Table 2-6

Table 2-7

Table 2-8

Chapter 3

Table 3-1

Table 3-2

Table 3-3

Table 3-4

Table 3-5

Table 3-6

Table 3-7

Chapter 4

Table 4-1

Chapter 5

Table 5-1

Table 5-2

Table 5-3

Table 5-4

Chapter 6

Table 6-1

Chapter 8

Table 8-1

Table 8-2

Table 8-3

Table 8-4

Table 8-5

Table 8-6

Chapter 9

Table 9-1

Table 9-2

Table 9-3

Table 9-4

Chapter 10

Table 10-1

Table 10-2

Table 10-3

Chapter 11

Table 11-1

Table 11-2

List of Illustrations

Chapter 1

Figure 1-1

The BeagleBone Black computing platform (revision C board with printed pin labels)

Figure 1-2

(a) The BeagleBone Black (BBB) in an Altoids tin box; (b) the BeagleBone White (BBW)

Figure 1-3

Table of BBB subsystems and connectors

Figure 1-4

The BeagleBone Black (BBB) top and bottom views

Figure 1-5

Table of functionality available on the P8 and P9 headers

Figure 1-6

(a) BBB connected to micro‐HDMI‐to‐HDMI adapter and then to a low‐cost HDMI‐A‐to‐DVI‐D cable (b) A micro‐HDMI‐to‐VGA adapter with audio line output

Figure 1-7

The USB‐to‐TTL 3.3V serial cable and its connection to the BBB (connection colors are black, brown, red, orange, yellow, and green)

Figure 1-8

(a) USB Wi‐Fi adapters; (b) the Logitech C920 camera; and (c) a Velleman USB hub (bus powered)

Figure 1-9

The LCD4 cape (top and bottom view)

Figure 1-10

(a) The Proto cape; (b) Valent F(x) LOGi‐Bone; (c) Camera cape; and (d) Adafruit BBB case

Chapter 2

Figure 2-1

The BBB START.htm guide to setting up your BBB

Figure 2-2

Windows Network Connections with Internet‐over‐USB connection LAN 9, and a web browser connection

Figure 2-3

Configuring the Network Connection Sharing Properties under Windows

Figure 2-4

Windows Device Manager and opening a PuTTY serial connection to the BBB

Figure 2-5

PuTTY SSH Configuration settings beside an open SSH terminal connection

Figure 2-6

The SSH Chrome App

Figure 2-7

The GNU nano editor being used to edit an example file in a PuTTY Linux terminal window

Figure 2-8

Connecting to the Node.js web server

Figure 2-9

The Cloud9 IDE (light theme) running on the BBB, executing the SimpleWebServer.js example

Chapter 3

Figure 3-1

The full boot sequence on the BBB

Figure 3-2

The Linux user space and kernel space

Figure 3-3

Linux directory listing and file permissions

Figure 3-4

The basic Git workflow

Figure 3-5

VirtualBox running Debian as a guest OS on a Windows host machine

Chapter 4

Figure 4-1

The Waveforms application generating a signal and displaying the response from the physical circuit

Figure 4-2

(a) Ohm’s law circuit example (b) Voltage divider example

Figure 4-3

(a) Potentiometers and using a variable voltage supply (b) Current divider example

Figure 4-4

The breadboard with a 7408 IC (quad two‐input AND gates)

Figure 4-5

Measuring voltage, current, and resistance

Figure 4-6

The KA7805A/LM7805 voltage regulator and an example regulator circuit

Figure 4-7

Circuit and behavior of a 1N4001 diode with a 5 V AC supply and a 1 kΩ load resistor

Figure 4-8

LED example and a circuit to drive an LED with appropriate forward current and voltage levels

Figure 4-9

Duty cycles of pulse width modulation (PWM) signals

Figure 4-10

Circuit and behavior of a 1N4001 diode with a 5 V AC supply, 1 kΩ load, and parallel 10 μF capacitor

Figure 4-11

Ceramic (nonpolarized) and electrolytic (polarized) capacitors and an example decoupling circuit

Figure 4-12

Bipolar junction transistors (BJTs)

Figure 4-13

The BJT as a switch

Figure 4-14

Realization of the transistor as a switch (saturation) and confirmation that all relationships hold true

Figure 4-15

Frequency response of the BJT circuit (frequency is 500 kHz and 1 MHz)

Figure 4-16

Field effect transistor (FET) as a switch

Figure 4-17

Frequency response of the FET circuit as the switching frequency is set at 1 MHz and 5 MHz

Figure 4-18

Optocoupler (617A) circuit with the captured input and output characteristics

Figure 4-19

Various switches and configurations

Figure 4-20

(a) Switch bouncing with no components other than the switch and 10 kΩ resistor (b) Low‐pass filtered output at point B (c) A Schmitt trigger circuit (d) Output of the Schmitt trigger circuit at point C, versus the input at point A

Figure 4-21

General logic gates

Figure 4-22

(a) IC package examples (b) The JK flip‐flop

Figure 4-23

Gate signal levels on the input and output of logic gates (a) TTL (b) CMOS at 5 V

Figure 4-24

An AND gate with the inputs accidentally left floating when the switches are open

Figure 4-25

Pull‐down and pull‐up resistors, used to ensure that the switches do not create floating inputs

Figure 4-26

Open‐drain level‐shifting example

Figure 4-27

(a) Sinking current on the output (b) TTL fan‐out example

Figure 4-28

(a) The ideal op‐amp (b) An open‐loop comparator example

Figure 4-29

Output of the comparator circuit

Figure 4-30

The voltage follower op‐amp circuit

Chapter 5

Figure 5-1

Building C/C++ applications on the BBB

Figure 5-2

Memory allocation for variables running on the 32‐bit BBB

Figure 5-3

Example of pointers in C/C++ on the BBB (with 32‐bit addresses)

Chapter 6

Figure 6-1

The BBB P8/P9 headers with pin names, which describe each pin's default functionality

Figure 6-2

A FET-driven LED circuit

Figure 6-3

Scope output measuring the current through the LED for the flash.sh script

Figure 6-4

A GPIO button input example

Figure 6-5

Internal pull-down resistor example, with an external resistor connected (a) from the pin to GND, and (b) from the pin to the 3.3 V supply

Figure 6-6

The BBB P8 header pins

Figure 6-7

The BBB P9 header pins

Figure 6-8

The BBB C++ class flashing the LED

Figure 6-9

ADC LDR circuit (not recommended)

Figure 6-10

ADC LDR circuit using a voltage-follower circuit (recommended)

Figure 6-11

Measured voltages and current values with the op-amp in a voltage-follower configuration

Figure 6-12

PWM cycle with period 10,000 ns (100 kHz) and duty cycle of 50%

Figure 6-13

PWM cycle with period 1,000 ns (1 MHz) and duty cycle of 50%

Figure 6-14

Controlling a servo motor using PWM, positioning from –90° to +90° using different pulse widths

Figure 6-15

Time delay in lighting an LED in response to a button press at ∼0% CPU usage (a) using sys/poll.h (b) integrating callback functions and Pthreads

Figure 6-16

(a) Push button configured with an internal pull-up resistor making it active low, and (b) the time response of the Bone Keys C++ example

Chapter 7

Figure 7-1

Creating a new C++ project in Eclipse: (a) the project settings, and (b) the cross-compiler prefix

Figure 7-2

The Eclipse IDE cross‐compiling a Hello World C++ example application

Figure 7-3

Eclipse Luna settings for cross‐compilation

Figure 7-4

Connecting to the BBB for the first time

Figure 7-5

The built‐in Terminals window, connected to the BBB and executing the cross‐compiled BBBTest C++ application

Figure 7-6

Eclipse GitHub integration, displaying the exploringBB repository

Figure 7-7

Setting the debug configuration

Figure 7-8

Setting up gdb‐multiarch

Figure 7-9

Setting the BBB gdbserver port

Figure 7-10

The Debug Perspective view

Figure 7-11

Example Doxygen HTML output

Figure 7-12

Doxygen Eclox plug‐in running within Eclipse

Figure 7-13

The Kernel Configuration tool

Chapter 8

Figure 8-1

(a) The I

2

C bus configuration; (b) connecting the ADXL345 to the I2C2 bus on the BBB

Figure 8-2

Timings required for single/multiple read/write operations on the ADXL345 device

Figure 8-3

Using i2cget to read the DEVID register value

Figure 8-4

(a) Using SPI to connect to one slave; (b) testing SPI using a Linux configuration

Figure 8-5

The 74HC595 SPI example

Figure 8-6

The 74HC595 SPI signal and output

Figure 8-7

The ADXL345 SPI communication timing chart (from the ADXL345 datasheet)

Figure 8-8

SPI1 Connection to the ADXL345

Figure 8-9

(a) Simple OOP structure (not recommended); (b) more appropriate OOP design

Figure 8-10

Reading the 0x00 register on the ADXL345 using SPI

Figure 8-11

ADXL345 three‐wire SPI communication

Figure 8-12

BBB control of more than one slave device using GPIO pins and additional logic

Figure 8-13

UART transmission format for a one‐byte transfer

Figure 8-14

(a) Loopback testing the UART; (b) configuring the minicom program settings

Figure 8-15

The Arduino platform

Figure 8-16

UART communication between the BBB and the Arduino Pro Mini 3.3 V

Figure 8-17

Analysis of the UART communication between the BBB and the Arduino Pro Mini 3.3 V

Figure 8-18

Sending the command “On\0” to the Arduino and receiving the response string “LED On”

Figure 8-19

Adafruit four‐channel, Adafruit eight‐channel, and Watterott four‐channel logic‐level translators

Figure 8-20

Switching BSS138‐based translators from 3.3 V to 5 V logic levels at 50 kHz, 200 kHz, and 1 MHz

Figure 8-21

Connecting a 5 V Arduino UART to the BBB UART using a logic‐level converter

Chapter 9

Figure 9-1

(a) A small DC motor with an integrated gearbox; (b) unidirectional control of a DC motor

Figure 9-2

Simplified H‐bridge description

Figure 9-3

Driving a DC motor using an example H‐Bridge driver breakout board

Figure 9-4

(a) Stepper motor external and internal structure; (b) full-step drive signals

Figure 9-5

Driving a stepper motor using the open‐hardware EasyDriver board

Figure 9-6

Wiring configuration for different stepper motor types

Figure 9-7

Driving a stepper motor using the BBB and the EasyDriver interface board

Figure 9-8

(a) Controlling a relay using the BBB; (b) an example breakout board

Figure 9-9

(a) A typical diode clamping circuit (not recommended); (b) the signal response of the circuit to an input signal that is in range; (c) the clipped signal response of the circuit to an input signal that is out of range

Figure 9-10

Protecting the ADC inputs using 1.8 V powered op-amps (recommended); (a) the circuit to protect all BBB analog inputs; (b) linear response characteristic; (c) clipped response to an out-of-range input; (d) clipped response to a significantly out-of-range input

Figure 9-11

Scaling an input signal using voltage division with op‐amp ADC protection in place

Figure 9-12

(a) A general op‐amp signal conditioning circuit that inverts the input; (b) conditioned output when Vin is 0 V to 5 V; (c) output when Vin is −5 V to +5 V; (d) conditioned and amplified output when the input signal is 1.9 V to 2.1 V

Figure 9-13

Signal conditioning circuit connected to the BBB with gain set using R

1

and R

2

and offset set using R

3

and R

4

Figure 9-14

(a) Sharp infrared distance measurement sensor; (b) its analog output response

Figure 9-15

(a) A voltage divider circuit configured for the GP2D12 sensor; (b) the plot of the exponentially fitted data

Figure 9-16

The ADXL335 analog accelerometer and its connection to the BBB with further signal conditioning

Figure 9-17

(a) Seven‐segment display; (b) typical pin ordering; (c) typical common anode and cathode display configurations

Figure 9-18

SPI interfacing to arrays of common cathode seven‐segment displays using daisy‐chained 74HC595 8‐bit serial shift registers

Figure 9-19

SPI interfacing to character LCD modules using a 74HC595 8‐bit serial shift register

Figure 9-20

Output from Listing 9‐10 on a Newhaven display module.

Figure 9-21

The COM20 serial console on the desktop machine as connected to the custom service

Figure 9-22

The COM20 serial console on the desktop machine as connected to the custom service

Figure 9-23

Bluetooth‐connected BeagleBone

Figure 9-24

Windows connecting to the BeagleBone using an on‐board Bluetooth interface

Figure 9-25

RealTerm connected to the BBB using the Bluetooth Port 22

Figure 9-26

An example App Inventor Android application that uses the Bluetooth code library

Chapter 10

Figure 10-1

Different software communication architectures implemented in this chapter

Figure 10-2

(a) The Analog Device TMP36 Temperature Sensor; (b) the Texas Instruments SensorTag

Figure 10-3

A first web page on the BBB

Figure 10-4

A simple CGI script example

Figure 10-5

Temperature sensor web page

Figure 10-6

A PHP temperature sensor

Figure 10-7

A ThingSpeak web sensor example

Figure 10-8

Xively channel with API keys

Figure 10-9

Example IFTTT recipe

Figure 10-10

Client/server example

Figure 10-11

BBB remote monitoring

Figure 10-12

A selection of Wi-Fi adapters and test results when they are connected to the BBB

Figure 10-13

AdaFruit

pseudo

-PoE cable

Figure 10-14

True PoE connection for the T-568B wiring scheme

Chapter 11

Figure 11-1

(a) Connection to an HDMI and a Bluetooth adapter (b) a Bluetooth keyboard/touchpad

Figure 11-2

Screen capture of the BBB monitor display

Figure 11-3

The CircuitCo LCD4 cape

Figure 11-4

VNC Viewer on Windows

Figure 11-5

The GTKsimple application

Figure 11-6

The GTKtemperature application

Figure 11-7

Qt “hello world” BBB example executing using VNC

Figure 11-8

QTimer signals and slots example

Figure 11-9

Qt Creator IDE visual design editor

Figure 11-10

The Qt EBB Temperature Sensor GUI application

Figure 11-11

The UI components and associated slots

Figure 11-12

The Qt fat‐client GUI application client/server architecture

Figure 11-13

The Menu and the Server Settings dialog

Figure 11-14

A multi‐threaded server

Figure 11-15

The Qt Accelerometer Client/Server application

Figure 11-16

The Qt Accelerometer Client/Server application program structure

Figure 11-17

Qt Creator “BeagleBone Kit” configuration

Chapter 12

Figure 12-1

Logitech USB HD webcams (a) C270, (b) C310, and (c) C920

Figure 12-2

The fswebcam webcam capture (640x360) displayed using gpicview via Xming

Figure 12-3

The OpenCV image processing example: (a) the webcam image; (b) the edge-processed image

Figure 12-4

OpenCV face detection on the BBB: (a) grabbed live using the C270 webcam; (b) loaded from the Lena image file

Figure 12-5

(a) Seven‐port USB hub with multiple adapters; (b) the Sound Blaster audio adapter; (c) the Dynamode USB audio adapter

Figure 12-6

Bluetooth A2DP connections: (a) Sony Hi‐Fi; (b) Windows machine via motherboard Bluetooth

Chapter 13

Figure 13-1

The PRU‐ICSS architecture

Figure 13-2

Summary of the steps involved in deploying a PRU‐ICSS program

Figure 13-3

An example BBB PRU circuit

Figure 13-4

The PRU example output

Figure 13-5

PRU register bit field notation

Figure 13-6

The PRU‐ICSS memory address maps

Figure 13-7

Summary of the PRU instruction set

Figure 13-8

(a) Button press test; (b) high‐frequency switching test output

Figure 13-9

The PWM generator output

Figure 13-10

User‐defined waveform output

Figure 13-11

The HC‐SR04 ultrasonic distance sensor circuit

Figure 13-12

Signal response of the HC‐SR04

Figure 13-13

Signal response of the HC‐SR04

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Introduction

The BeagleBone is amazing! Given the proliferation of smartphones, the idea of holding in one hand a computer that is capable of performing two billion instructions per second is easy to take for granted—but the fact that you can modify the hardware and software of such a small yet powerful device and adapt it to suit your own needs and create your own inventions is nothing short of amazing. Even better, you can purchase it for as little as $45–$55.

The BeagleBone board on its own is too complex a device to be used by a general audience; it is the ability of the BeagleBone to run embedded Linux that makes the resulting platform accessible, adaptable, and powerful. Together, Linux and embedded systems enable ease of development for devices that can meet future challenges in smart buildings, the Internet of Things (IoT), robotics, smart energy, smart cities, human-computer interaction (HCI), cyber-physical systems, 3D printing, advanced vehicular systems, and many, many more applications.

The integration of high-level Linux software and low-level electronics represents a paradigm shift in embedded systems development. It is revolutionary that you can build a low-level electronics circuit and then install a Linux web server, using only a few short commands, so that the circuit can be controlled over the Internet. You can easily use the BeagleBone as a general-purpose Linux computer, but it is vastly more challenging and interesting to get underneath the hood and fully interface it to electronic circuits of your own design—and that is where this book comes in!

This book should have widespread appeal for inventors, makers, students, entrepreneurs, hackers, artists, dreamers—in short, anybody who wants to bring the power of embedded Linux to their products, inventions, creations, or projects and truly understand the BeagleBone in detail. This is not a recipe book—with few exceptions, everything demonstrated here is explained at a level that will enable you to design, build, and debug your own extensions of the concepts presented here. Nor is there any grand design project at the end of this book for which you must purchase a prescribed set of components and peripherals in order to achieve a very specific outcome. Rather, this book is about providing you with enough background knowledge and “under-the-hood” technical details to enable and motivate your own explorations.

I strongly believe in learning by doing, so I present low-cost, widely available hardware examples in order that you can follow along. Using these hands-on examples, I describe what each step means in detail, so that when you substitute your own hardware components, modules, and peripherals you will be able to adapt the content in this book to suit your needs. As for that grand project or invention—that is left up to you and your imagination!

When writing this book I had the following aims and objectives:

To explain embedded Linux and its interaction with electronic circuits—taking you through the topics from mystery to mastery!

To provide in-depth information and instruction on the Linux, electronics, and programming skills that are required to master a pretty wide and comprehensive variety of topics in this domain.

To create a collection of practical “Hello World” hardware and software examples on each and every topic in the book, from low-level interfacing, general-purpose input/outputs (GPIOs), analog-to-digital converters (ADCs), buses, and UARTs, to high-level libraries such as OpenCV, Qt, and complex and powerful topics, such as real-time interfacing with the PRU-ICSS.

To ensure that each circuit and segment of code is specifically designed to work on the BeagleBone. Every single circuit and code example in this book was built and tested on the BeagleBone.

To use the “Hello World” examples to build a library of code that you can use and adapt for your own BeagleBone projects.

To make all of the code available on GitHub in an easy-to-use form.

To support this book with strong digital content, such as the videos on the DerekMolloyDCU YouTube channel, and a custom website

www.exploringbeaglebone.com

, which has been developed specifically to support this book.

To ensure that by the end of this book you have everything you need to imagine, create, and build

advanced

BeagleBone projects.

Why the BeagleBone Black?

The BeagleBone Black is a powerful single-board computer (SBC), and while there are other SBCs available on the market such as the Raspberry PI and the Intel Galileo, the BeagleBone has one key differentiator—it was built to be interfaced to! For example, the BeagleBone's microprocessor even contains two additional on-chip microcontrollers that can be used for real-time interfacing—an area in which other Linux SBCs have significant difficulty.

Unlike most other SBCs, the BeagleBone is fully open source hardware. The BeagleBoard.org Foundation provides source schematics, hardware layout, a full bill of materials, and technical reference manuals, enabling you to modify the design of the BeagleBone platform and integrate it into your own product. In fact, you can even fork the hardware design on Upverter (www.upverter.com) under a Creative Commons Attribution-ShareAlike license (see tiny.cc/ebb002 for the full schematics). This is a very useful feature should you decide to take your newest invention to market!

How This Book Is Structured

There is no doubt that some of the topics in this book are quite complex—the BeagleBone is a complex device! However, everything that you need to master the device is present in the book within three major parts:

Part I: BeagleBone Basics

Part II: Interfacing, Controlling, and Communicating

Part III: Advanced BeagleBone Systems

In the first part in the book, I introduce the hardware and software of the BeagleBone platform in Chapters 1 and 2, and subsequently provide three primer chapters:

Chapter 3: Exploring Embedded Linux Systems

Chapter 4: Interfacing Electronics

Chapter 5: Practical BeagleBone Programming

If you are a Linux expert, electronics wizard, and/or software guru, then feel free to skip the primer chapters; however, for everyone else I have put in place a concise but detailed set of materials to ensure that you gain all the knowledge required to effectively and safely interface to the BeagleBone.

In the second part of the book, Chapters 6 to 9, I provide detailed information on interfacing to the BeagleBone GPIOs, analog inputs, buses (I2C, SPI), UART devices, and USB peripherals. You'll learn how you can configure a cross-compilation environment so that you can build large-scale software applications for the BeagleBone. This part also describes how you can combine hardware and software in order to provide the BeagleBone with the ability to interact effectively with its physical environment.

The final part of the book, Chapters 10 to 13, describe how the BeagleBone can be used for advanced applications such as Internet of Things (IoT); rich user interfaces; images, video, and audio; and real-time interfacing. Along the way you will meet many technologies, including TCP/IP, ThingSpeak, Xively, PoE, Wi-Fi, Bluetooth, cron, Apache, PHP, e-mail, IFTTT, VNC, GTK+, Qt, XML, multi-threading, client/server programming, V4L2, video streaming, OpenCV, Boost, USB audio, Bluetooth A2DP, text-to-speech, and the PRU-ICSS.

Conventions Used in This Book

This book is filled with source code examples and snippets that you can use to build your own applications. Code and commands are shown as follows:

This is what source code looks like.

When presenting work performed in a Linux terminal it is often necessary to display both input and output in a single example. A bold type is used to distinguish the user input from the output—for example:

molloyd@beaglebone:~$

ping

www.exploringbeaglebone.com

PING lb1.reg365.net (195.7.226.20) 56(84) bytes of data. 64 bytes from lb1.reg365.net (195.7.226.20): icmp_req=1 ttl=55 time=25.6 ms 64 bytes from lb1.reg365.net (195.7.226.20): icmp_req=2 ttl=55 time=25.6 ms ...

The $ prompt indicates that a regular Linux user is executing a command, and a # prompt indicates that a Linux superuser is executing a command. The ellipsis symbol “...” is used whenever code or output not vital to understanding a topic has been cut. Editing the output like this enables you to focus on only the most useful information. You are encouraged to repeat the steps in this book yourself, whereupon you will see the full output. In addition, the full source code for all examples is provided along with the book.

There are some additional styles in the text. For example:

New terms and important words appear in

italics

when introduced.

Keyboard strokes appear like this: Ctrl+C.

All URLs in the book refer to HTTP addresses and appear like this:

www.exploringbeaglebone.com

.

A URL shortening service is used to create aliases for long URLs that are presented in the book. These aliases have the form

tiny.cc/ebb102

(e.g., link two in Chapter 1). Should the link address change after this book is published, the alias will be updated.

There are several features used in this book to identify when content is of particular importance or when additional information is available:

      WARNING     This type of feature contains important information that can help you avoid damaging your BeagleBone.

      NOTE     This type of feature contains useful additional information, such as links to digital resources and useful tips, which can make it easier to understand the task at hand.

FEATURE TITLE

This type of feature goes into detail about the current topic or a related topic.

What You'll Need

Ideally you should have a BeagleBone Black before you begin reading this book so that you can follow along with the numerous examples in the text. Presently the board is manufactured by both CircuitCo and Embest—the boards from either manufacturer are compatible with the designs and operations in this book. You can purchase one of the boards in the U.S. from online stores such as Adafruit Industries, Digi-Key, Mouser, SparkFun, and Jameco Electronics. They are available internationally from stores such as Farnell, Radionics, Watterott, and Tigal.

A full list of recommended and optional accessories for the BeagleBone is provided in Chapter 1—if you do not yet have a BeagleBone, it would be worth reading that chapter before placing an order. In addition, each chapter contains a list of the electronics components and modules required if you wish to follow along with the text. The book website provides details about where these components can be acquired.

Errata

We have worked really hard to ensure that this book is error free; however, it is always possible that some were overlooked. A full list of errata is available on each chapter's web page at the companion website. If you find any errors in the text or in the source code examples, I would be grateful if you could please use the companion website to send them to me so that I can update the web page errata list and the source code examples in the code repository.

Digital Content and Source Code

The primary companion site for this book is www.exploringbeaglebone.com. It is maintained by the book's author and contains videos, source code examples, and links to further reading. Each chapter has its own individual web page. In the unlikely event that the website is unavailable, you can find the code at www.wiley.com/go/exploringbeaglebone.

I have provided all of the source code through GitHub, which allows you to download the code to your BeagleBone with one command. You can also easily view the code online at tiny.cc/ebb001. Downloading the source code to your BeagleBone is as straightforward as typing the following at the Linux shell prompt:

$

git clone

https://github.com/derekmolloy/exploringBB.git

If you have never used Git before, don't worry—it is explained in detail in Chapter 3. Now, on with the adventures!

Part IBeagleBone Basics

In This Part

Chapter 1: The BeagleBone Hardware

Chapter 2: The BeagleBone Black Software

Chapter 3: Exploring Embedded Linux Systems

Chapter 4: Interfacing Electronics

Chapter 5: Practical BeagleBone Programming