Exploring BeagleBone

Introduction xxv Part I BeagleBone Basics 1 Chapter 1 The BeagleBone Hardware 3 Introduction to the Platform 3 Who Should Use the BeagleBone 5 When to Use the BeagleBone 6 When You Should Not Use the BeagleBone 6 BeagleBone Documentation 7 The BeagleBone Hardware 8 BeagleBone Versions 9 The BeagleBone Black Hardware 11 BeagleBone Accessories 14 Highly Recommended Accessories 14 Micro?]SD Card (for Flashing the BBB) 14 External 5V Power Supply (for Flashing and Peripherals) 15 Ethernet Cable (for Network Connection) 15 HDMI Cable (for Connection to Monitors/Televisions) 15 USB to Serial UART TTL 3.3 V (for Finding Problems) 16 Optional Accessories 17 USB Hub (to Connect Several USB Devices to a USB Host) 17 Micro-HDMI to VGA adapters (for VGA Video and Sound) 17 Wi-Fi Adapters (for Wireless Networking) 18 USB Webcam (for Capturing Images and Streaming Video) 18 USB Keyboard and Mouse (for General-Purpose Computing) 18 Capes 19 How to Destroy Your BeagleBone! 20 Summary 22 Support 22 Chapter 2 The BeagleBone Black Software 23 Linux on the BeagleBone 24 Linux Distributions 24 Communicating with the BBB 25 Installing Drivers 26 Network Connections 26 Internet?]over?]USB 26 Regular Ethernet 29 Ethernet Crossover Cable 30 Communicating with the BBB 31 Serial Connection over USB 31 Serial Connection with the USB?]to?]TTL 3.3 V Cable 33 Connecting through Secure Shell (SSH) 33 Secure Shell Connections using PuTTY 34 Chrome Apps: Secure Shell Client 34 Transferring Files Using PuTTY/psftp over SSH 35 Controlling the BeagleBone 37 Basic Linux Commands 37 First Steps 37 Basic File System Commands 38 Environment Variables 40 Basic File Editing 41 What Time Is It? 42 Package Management 44 Interacting with the BBB On?]board LEDs 45 Shutdown 47 Node.js, Cloud9, and BoneScript 48 Introduction to Node.js 48 Introduction to the Cloud9 IDE 50 Introduction to BoneScript 51 Summary 52 Further Reading 53 Chapter 3 Exploring Embedded Linux Systems 55 Embedded Linux Basics 55 What Embedded Linux Offers 57 Is Linux Open Source and Free? 57 Booting the BeagleBone 58 The BeagleBone Bootloaders 58 Kernel Space and User Space 62 System V init (SysVinit) 63 Managing Linux Systems 67 The Super User 67 System Administration 68 The Linux File System 68 Linking to Files and Directories 69 Users and Groups 71 File System Permissions 74 Exploring the File System 75 Commands for File Systems 75 find and whereis 81 more or less 82 Linux Commands 82 Standard Input and Output Redirection (>, >>, and Pipes (| and tee) 83 Filter Commands (from sort to xargs) 84 echo and cat 86 diff 87 tar 88 md5sum 88 Linux Processes 89 Controlling Linux Processes 89 Foreground and Background Processes 90 The BusyBox Multi?]call Binary 92 Other Linux Topics 93 Git 93 Getting Started with Git 94 Cloning a Repository (git clone) 95 Getting the Status (git status) 96 Adding to the Staging Area (git add) 96 Committing to the Local Repository (git commit) 97 Pushing to the Remote Repository (git push) 97 Advanced Git 98 Creating a Branch (git branch) 98 Merging the Branch (git merge) 100 Deleting a Branch (git branch ?]d) 100 Conclusions on Git 101 Desktop Virtualization 102 Code for This Book 103 Summary 104 Further Reading 104 Chapter 4 Interfacing Electronics 105 Recommended Equipment 105 Digital Multimeter 106 Oscilloscopes 106 Basic Circuit Principles 108 Voltage, Current, Resistance, and Ohm's Law 109 Voltage Division 110 Current Division 112 Implementing Circuits on a Breadboard 113 Digital Multimeters (DMMs) and Breadboards 114 Example Circuit: Voltage Regulation 115 Discrete Components 117 Diodes 117 Light?]Emitting Diodes (LEDs) 118 Smoothing and Decoupling Capacitors 121 Transistors 123 Transistors as Switches 124 Field Effect Transistors (FETs) as Switches 127 Optocouplers/Opto?]isolators 128 Switches and Buttons 130 Hysteresis 132 Logic Gates 133 Floating Inputs 137 Pull?]Up and Pull?]Down Resistors 138 Open?]Collector and Open?]Drain Outputs 139 Interconnecting Gates 140 Analog?]to?]Digital Conversion 141 Sampling Rate 142 Quantization 142 Operational Amplifiers 143 Ideal Operational Amplifiers 143 Negative Feedback and Voltage Follower 146 Positive Feedback 146 Concluding Advice 147 Summary 147 Further Reading 148 Chapter 5 Practical BeagleBone Programming 149 Introduction 149 Performance of Different Languages 150 Setting the BBB CPU Frequency 153 Scripting Languages 153 Scripting Language Options 154 Bash 155 Perl 157 Python 158 JavaScript and Java 161 JavaScript and Node.js on the BBB 161 Java on the BBB 164 C and C++ on the BeagleBone 167 C and C++ Language Overview 169 Compiling and Linking 170 Writing the Shortest C/C++ Program 172 Variables and Operators in C/C++ 174 Pointers in C/C++ 177 C?]Style Strings 180 LED Flashing Application in C 181 The C of C++ 183 First Example and Strings in C++ 183 Passing by Value, Pointer, and Reference 185 Flashing the LEDs Using C++ (non?]OO) 186 Writing Your Own Multi?]Call Binary 186 C++ with Classes 187 Overview of Object?]Oriented Programming 188 Classes and Objects 188 Encapsulation 189 Inheritance 190 Object?]Oriented LED Flashing Code 191 /Proc--Process Information File System 195 GLIBC and Syscall 195 Summary 197 Further Reading 197 Part II Interfacing, Controlling, and Communicating 199 Chapter 6 Interfacing to the BeagleBone Input/Outputs 201 General?]Purpose Input/Outputs 201 Introduction to GPIO Interfacing 202 GPIO Digital Output 204 GPIO Digital Input 207 GPIO Confi guration 208 Internal Pull?]up and Pull?]down Resistors 208 GPIO Pin Configuration Settings 209 C++ Control of GPIOs 214 The Linux Device Tree 219 The Flattened Device Tree (FDT) 219 Device Tree Overlays (DTOs) 221 Writing an Overlay 221 Compiling and Deploying an Overlay 222 The BBB Cape Manager 222 Loading a Device Tree Overlay 223 Removing an Overlay 225 Loading an Overlay on Boot 226 Analog Inputs and Outputs 226 Analog Inputs 226 Enabling the Analog Inputs 227 Input Application--A Simple Light Meter 228 Analog Outputs (PWM) 231 Output Application--Controlling a Servo Motor 233 Advanced GPIO Topics 235 More C++ Programming 235 Callback Functions 235 POSIX Threads 236 Linux poll (sys/poll.h) 238 Enhanced GPIO Class 239 GPIO?]KEYS 243 Using GPIOs without Using sudo 247 Summary 248 Further Reading 249 Chapter 7 Cross?]Compilation and the Eclipse IDE 251 Setting Up a Cross?]Compilation Toolchain 251 A Toolchain for Debian 252 Testing the Toolchain 254 Cross?]Compilation with Third?]Party Libraries (Multiarch) 255 Installing a Change Root 257 Installing an armhf Change Root 257 Emulating the armhf Architecture 258 Cross?]Compilation Using Eclipse 260 Installing Eclipse on Desktop Linux 260 Configuring Eclipse for Cross?]Compilation 261 Remote System Explorer 263 Integrating GitHub into Eclipse 265 Remote Debugging 266 Automatic Documentation (Doxygen) 269 Adding Doxygen Support in Eclipse 270 Building Debian for the BBB 271 Summary 273 Further Reading 274 Chapter 8 Interfacing to the BeagleBone Buses 275 Introduction to Bus Communication 276 I2C 276 I2C Hardware 277 The ADXL345 Accelerometer 279 Using Linux I2C?]Tools 280 i2cdetect 280 i2cdump 281 i2cget 283 i2cset 285 I2C Communication in C 286 Wrapping I2C Devices with C++ Classes 288 SPI 291 SPI Hardware 291 SPI on the BBB 293 Enabling the First SPI Bus (SPI0) 294 Testing the SPI Bus 295 A First SPI Application (74HC595) 296 Wiring the 74HC595 Circuit 296 SPI Communication Using C 297 Bidirectional SPI Communication in C++ 300 The Second SPI Bus (SPI1) 301 The ADXL345 SPI Interface 301 Connecting the ADXL345 to the BBB 302 Wrapping SPI Devices with C++ Classes 303 Three?]Wire SPI Communication 307 Multiple SPI Slave Devices on the BBB 308 UART 309 UARTs on the BBB 310 The Arduino UART Example 312 BeagleBone to Arduino Serial Communication 314 Echoing the Minicom Program 314 UART Echo Example in C 316 UART Command Control of an Arduino 318 Logic?]Level Translation 321 Summary 324 Further Reading 324 Chapter 9 Interacting with the Physical Environment 325 Interfacing to Actuators 326 DC Motors 327 A BBB DC Motor Driver Circuit 329 Controlling a DC Motor Using sysfs 330 Controlling a DC Motor Using C++ 331 Stepper Motors 333 The EasyDriver Stepper Motor Driver 334 A BBB Stepper Motor Driver Circuit 335 Controlling a Stepper Motor Using C++ 336 Relays 338 Interfacing to Analog Sensors 340 Protecting the BBB ADC Inputs 342 Diode Clamping 342 Op?]Amp Clamping 343 Analog Sensor Signal Conditioning 345 Scaling Using Voltage Division 345 Signal Offsetting and Scaling 346 Analog Interfacing Examples 349 Infrared Distance Sensing 349 ADXL335 Conditioning Example 353 Interfacing to Display Modules 354 Seven?]Segment Displays 354 Character LCD Modules 359 Remote Control BeagleBone 363 Managing Services with Systemd 364 BBB Serial Connection to Desktop 366 Starting a Custom Service on Boot 369 Bluetooth 370 Installing an Adapter 370 Loadable Kernel Modules 371 Configuring a Bluetooth Adapter 372 Making the BBB Discoverable 373 Android Application Development with Bluetooth 374 Building Dynamic Linked Libraries 376 Summary 376 Further Reading 377 Part III Advanced BeagleBone Systems 379 Chapter 10 The Internet of Things 381 The Internet of Things (IoT) 382 More Sensors (Things!) 384 A Room Temperature Sensor 384 Texas Instruments SensorTag 385 Connecting to Bluetooth Smart Devices 385 Building a Linux Package 386 Controlling a Bluetooth Smart Device 387 The BeagleBone as a Web Server 388 Installing a Web Server 389 Configuring an Apache Web Server 389 Creating Web Pages and Web Scripts 390 PHP on the BeagleBone 392 Replacing Bone101 with the Custom Web Server 393 A C/C++ Web Client 394 Network Communications Primer 395 A C/C++ Web Client 396 Secure Communication Using OpenSSL 398 The BeagleBone as a Web Sensor 399 ThingSpeak 400 The Linux Cron Scheduler 402 System crontab 402 User crontab 404 Xively 405 Getting Started with Xively's PaaS 406 The Xively C Library 407 Sending E-mail from the BBB 409 If This Then That (IFTTT) 411 The C++ Client/Server 412 Managing Remote IoT Devices 415 BeagleBone Remote Monitoring 416 Linux Watchdog Timer 416 IoT Physical Networking 418 The BeagleBone and Wi-Fi 418 Wireless Network Adapters 419 Static IP Addresses 422 Power over Ethernet (PoE) 423 PoE Power Extraction Modules (PEMs) (Advanced Topic) 424 Summary 425 Further Reading 426 Note 426 Chapter 11 BeagleBone with a Rich User Interface 427 Rich UI BBB Architectures 428 The BBB as a General?]Purpose Computer 428 Connecting a Bluetooth Input Peripheral 430 BBB with a LCD Touch Screen Cape 431 Virtual Network Computing (VNC) 432 VNC Using VNC Viewer 433 VNC with Xming and PuTTY 433 VNC with a Linux Desktop Computer 434 Fat?]Client Applications 435 Rich UI Application Development 435 Introduction to GTK+ on the BBB 436 The "Hello World" GTK+ Application 436 The Event?]Driven Programming Model 437 The GTK+ Temperature Application 438 Introduction to Qt on the BBB 441 Installing Qt Development Tools on the BBB 442 The "Hello World" Qt Application 442 Qt Primer 444 Qt Concepts 444 The QObject Class 445 Signals and Slots 446 Qt Development Tools 447 A Qt Temperature Sensor GUI Application 448 Simple Qt Cross?]Platform Development 453 Remote UI Application Development 455 Fat?]Client Qt GUI Application 455 Multi?]Threaded Server Applications 458 A Multi?]Threaded Temperature Service 461 The Fat?]Client as a Server 463 Parsing Stream Data 465 The BBB Client Application 467 Cross?]Compiling Qt Applications 468 Building the Qt Libraries from Source 470 Remote Deploying a Test Application 470 Summary 471 Further Reading 472 Chapter 12 Images, Video, and Audio 473 Capturing Images and Video 474 USB Webcams 474 Video4Linux2 (V4L2) 476 Image Capture Utility 477 Video4Linux2 Utilities 479 Writing Video4Linux2 Programs 480 Streaming Video 482 Image Processing and Computer Vision 483 Image Processing with OpenCV 484 Computer Vision with OpenCV 486 Boost 489 BeagleBone Audio 489 Core Audio Software Tools 490 Audio Devices for the BBB 491 HDMI and USB Audio Playback Devices 491 Internet Radio Playback 493 Recording Audio 494 Audio Network Streaming 496 Bluetooth A2DP Audio 496 Text?]to?]Speech 499 Online Text-to-Speech 499 Offline Text-to-Speech 500 A Bluetooth Speaking Clock and Temperature Sensor 500 Summary 502 Further Reading 502 Chapter 13 Real?]Time BeagleBone Interfacing 503 Real?]Time BeagleBone 504 Real?]Time Kernels 504 Real?]Time Hardware Solutions 505 The PRU?]ICSS Architecture 506 Important Documents 508 Getting Started with the PRU?]ICSS 508 PRU?]ICSS Enhanced GPIOs 509 PRU?]ICSS Device Tree Overlay 509 The PRU?]ICSS Package 511 A First PRU Program 512 The PRU?]ICSS in Detail 516 Registers 516 Local and Global Memory 517 PRU Assembly Instruction Set 519 Applications of the PRU?]ICSS 521 PRU?]ICSS Performance Tests 522 Utilizing Regular Linux GPIOs 522 A PRU PWM Generator 525 A PRU Sine Wave Generator 527 An Ultrasonic Sensor Application 530 Additional PRU?]ICSS Tools 535 The PRU Debugger 535 The TI PRU C Compiler 536 Summary 538 Further Reading 539 Index 541