Raspberry Pi Computer Architecture Essentials

Table of Contents

Raspberry Pi Computer Architecture Essentials

Credits

About the Author

About the Reviewer

www.PacktPub.com

eBooks, discount offers, and more

Why subscribe?

Preface

What this book covers

What you need for this book

Who this book is for

Conventions

Reader feedback

Customer support

Downloading the example code

Errata

Piracy

Questions

1. Introduction to the Raspberry Pi's Architecture and Setup

History and background of the Raspberry Pi

Raspberry Pi hardware specifications

Dimensions

System on Chip

CPU

GPU

SDRAM

4 USB 2.0 ports and 1 SoC on-board USB

MicroSD card port

Ethernet port

Audio

GPIO pins

Video – analog TV out

Video – HDMI port

Basic hardware needed

The microSD card – the main storage and boot device of the Raspberry Pi 2

Preinstalled microSD card versus creating your own

The NOOBS operating system installation manager

Downloading the latest version of Raspbian

Setting up your microSD card and installing the Raspbian operating system

Raspbian installation wrap-up

Check SSH is running

RSA key generation for SSH

Linux and Mac RSA key generation

Windows RSA key generation

Assign a static IP to your Raspberry Pi 2

Installing Screen and Vim

Vim – an optional handy text editor

Running tests on the OS and configuration changes

Diagnostic tests

Over and underclocking the Raspberry Pi

Going further – testing the GPIO pins

Some handy Linux commands

Troubleshooting

Summary

2. Programming on Raspbian

Which programming languages?

Assembly language

Assembling and linking

The C and C++ languages

C – a brief introduction

A quick look at C++

Our first C program

Geany – a handy text editor and development environment

Creating a new C program

C libraries – a trove of reusable code

The C (and C++) compiler

Compiling and running our application

The Python language

A simple Python program

Running a Python program from a file

Summary

3. Low-Level Development with Assembly Language

Back to basics

Multiline comments

Directives

Single line comments

Registers

Branching

The assembler

The linker

Makefiles

Memory and addresses

The .data directive

The .balign directive

Words

Labels

The memory

The addresses

LDR and SUB

Running our program

Adding power to our program – control structures

If else statements

Iteration

Testing our control structures

Summary

4. Multithreaded Applications with C/C++

What are threads?

Thread types

User level threads

Kernel level threads

Hybrid threads

POSIX threads

Steps involved in implementing threads

Creation and termination

Synchronization

Scheduling

An example in C

Trying out our program

A C++ equivalent

The g++ command

Going further – mutexes and joins

Compile and test

Summary

5. Expanding on Storage Options

Booting up

Setting up the external HDD

Getting the disk name

Setting up the HDD

Modifying cmdline.txt

Network-attached storage (NAS)

Installing Samba

Testing the NAS

Mac

Linux

Windows

Summary

6. Low-Level Graphics Programming

VideoCore IV GPU

Sample programs

Accessing the frame buffer

Check the display settings

Testing our C code

Filling the screen with a color

A C program to turn the screen red

Compile and run the C program

Drawing a line

Plotting pixels and drawing lines

Compile and run

Next steps – polygons

Summary

7. Exploring the Raspberry Pi's GPIO Pins

Introduction to GPIO pins

Standard GPIO

I2C

Serial Rx and Tx

SPI

PWM and PPM

GPIO power voltages

Hardware choices

Prototyping shields and boards

Cooking Hacks Arduino bridge shield

Connecting directly to the GPIO pins

Switching an LED on and off

Setting up the hardware

C blinking LED program

Python blinking LED program

Reading data from the GPIO pins in Python

Summary

8. Exploring Sound with the Raspberry Pi 2

Introduction to the Raspberry Pi's sound

Configuring the audio output

Setting the audio output

Interacting with audio through GPIO

Installing the audio drivers

Hardware setup

Loading drivers

Getting some drum tracks

Python drum machine

Audio shields for the Raspberry Pi

C and ALSA

ALSA examples

Introducing Sonic Pi

Setup

Experimenting with Sonic Pi

Summary

9. Building a Web Server

Introduction to web servers

HTTP requests

HTML

Popular web servers available on the Raspberry Pi

Apache

NGINX

Building a Python web server

Python web server code

Adding an index page and a favicon

Adding database support

SQLite

SQL – a quick overview

Python program with SQLite support

Flask – displaying database data via Python

Next steps

Summary

10. Integrating with Third-Party Microcontrollers

Genuino/Arduino microcontroller

Setting up the Arduino software

Installing the IDE on your Raspberry Pi 2

A quick guide to the Arduino IDE

Integration with Arduino

Serial communication over USB

Communication between the Arduino and Raspberry Pi via GPIO

Communication over I2C

Communication over the Web

Summary

11. Final Project

Choose your storage mechanism

Building a Flask-based website

Adding a database

A basic website

Web forms

Add

Edit

Adding in an LED

Building the circuit – a recap

Integrating with our Python app

Extending the project further

Replace the LED with a screen

E-mail support

Playing a sound

Summary

Index

Raspberry Pi Computer Architecture Essentials

Raspberry Pi Computer Architecture Essentials

Copyright © 2016 Packt Publishing

All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embedded in critical articles or reviews.

Every effort has been made in the preparation of this book to ensure the accuracy of the information presented. However, the information contained in this book is sold without warranty, either express or implied. Neither the author, nor Packt Publishing, and its dealers and distributors will be held liable for any damages caused or alleged to be caused directly or indirectly by this book.

Packt Publishing has endeavored to provide trademark information about all of the companies and products mentioned in this book by the appropriate use of capitals. However, Packt Publishing cannot guarantee the accuracy of this information.

First published: March 2016

Production reference: 1170316

Published by Packt Publishing Ltd.

Livery Place

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Birmingham B3 2PB, UK.

ISBN 978-1-78439-797-5

www.packtpub.com

Credits

Author

Andrew K. Dennis

Reviewer

Ed Snajder

Commissioning Editor

Amarabha Banerjee

Acquisition Editor

Divya Poojari

Content Development Editor

Trusha Shriyan

Technical Editor

Shivani Kiran Mistry

Copy Editor

Safis Editing

Project Coordinator

Kinjal Bari

Proofreader

Safis Editing

Indexer

Rekha Nair

Production Coordinator

Melwyn Dsa

Cover Work

Melwyn Dsa

About the Author

Andrew K. Dennis is the manager of professional services software development at Prometheus Research. Prometheus Research is a leading provider of integrated data management for research and is the home of HTSQL, an open source navigational query language for RDBMS.

Andrew has a diploma in computing, a BSc in software engineering, and is currently studying for a second BSc in creative computing in his spare time.

He has over 12 years of experience working in the software industry in the UK, Canada, and the USA. This experience includes e-learning courseware development, custom CMS and LMS development, SCORM consultancy, web development in a variety of languages, open source application development, blogging about the integration of web technologies with electronics for home automation, and punching lots of Cat5 cables.

His interests include web development, e-learning, 3D printing, Linux, the Raspberry Pi and Arduino, open source projects, home automation and the use of web technology in this sphere, amateur electronics, home networking, and software engineering.

About the Reviewer

Ed Snajder is a database engineer and hardware hacker working at Jive Software. When not breaking databases and distributed data systems, Ed spends a lot of time in the community evangelizing Raspberry Pi, Arduino, and open source 3D printing. His belief is that if every child could have a Raspberry Pi, we will soon have the flying cars we've always dreamed of. He lives in Portland, Oregon, with his partner, Lindsay and his Shih-Tzus, Obi-wan and Gizmo.

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Preface

Are you interested in the myriad features of your Raspberry Pi 2? From the hardware to the software, do you wish to understand how you can interact with these features?

Then this is the book for you!

The Raspberry Pi 2 is one of the latest hardware offerings in the Raspberry Pi family. With many new and improved features than previous versions, there is so much more an enthusiast can do.

This book will walk you through how you can get the most out of your device.

You will learn about how to program on the Raspberry Pi using the Assembly language, Python, and C/C++. This will include building a web server in Python and saving data to an SQLite database. Ever wondered what threads are? These are covered here too.

In addition to this, you will explore the various types of GPIO pins and how these can be used to interact with third party microcontrollers and electronic circuits.

The sound and graphics capabilities of the Raspberry Pi 2 are also experimented with through a number of projects. And to expand the Raspberry Pi's storage option, we will also set up an external HDD via USB.

Finally, the book concludes with a project that brings together many of the technologies explained throughout the chapters.

By the time you finish reading this book, you'll have a firm knowledge of the Raspberry Pi 2 and how you can devise your own projects that use its capabilities.

What this book covers

Chapter 1, Introduction to the Raspberry Pi's Architecture and Setup, provides an introduction to the Raspberry Pi and its hardware architecture. We will explore the various hardware components in detail, and this will provide a basis for the programming projects in future chapters. A quick guide to getting Raspbian installed and SSH enabled is also provided.

Chapter 2, Programming on Raspbian, provides an introduction to the programming languages used in this book. An explanation will be provided of which language is used and why. This chapter will also guide you through setting up the tools for Assembler, C/C++, and Python. Three introduction programs will then be walked through to give you the opportunity to test that your setup works.

Chapter 3, Low-Level Development with Assembly Language, explores programming in the Raspbian operating system using the Assembler programming language.

Chapter 4, Multithreaded Applications with C/C++, having looked at Assembler, we move up the programming hierarchy to C/C++. We learn how to write multithreaded applications and understand their usefulness. Through these applications, we learn more about the multi-core CPU of the Raspberry Pi 2.

Chapter 5, Expanding on Storage Options, offers a guide to expanding the storage options of the Raspberry Pi beyond the SD card.

Chapter 6, Low-Level Graphics Programming, shows you how to interact with the graphics hardware on the Raspberry Pi 2. Here you will learn how to draw to the screen via the frame buffer.

Chapter 7, Exploring the Raspberry Pi's GPIO Pins, shows you how to interact with electronic components using the Raspberry PI's GPIO pins. Here we look at how Python libraries can be used to simplify the process.

Chapter 8, Exploring Sound with the Raspberry Pi 2, gives an introduction to the basics of sound programming using the Raspberry Pi's hardware. Learn about live coding via the Sonic-Pi IDE to generate your own algorithmic music.

Chapter 9, Building a Web Server, expands upon your knowledge of Python to build a web server via Flask. This chapter explores the Ethernet and Wi-Fi capabilities of the Raspberry Pi for delivering web-based applications. In this chapter, you will also learn about using SQLite to store data and display it via a web page. Topics covered also include Apache and NGINX.

Chapter 10, Integrating with Third-Party Microcontrollers, in this chapter we learn how to interact with third-party microcontrollers such as the Arduino. These devices can form the basis of robotics projects and augment the abilities of the Raspberry Pi.

Chapter 11, Final Project, will conclude the book with a final project that brings together many of the topics explored throughout previous chapters.

What you need for this book

The following list provides an overview of the recommended and optional hardware needed for the projects in this book. Where hardware is needed for a specific chapter, the relevant chapter is listed:

Raspberry Pi 2.

USB keyboard.

HDMI monitor.

USB mouse.

MicroSD card.

Wall power unit for the Raspberry Pi 2.

A working Internet connection.

A selection of wires for connecting to the GPIO pins; 12 recommended for Chapter 7, Exploring the Raspberry Pi's GPIO pins, Chapter 10, Integrating with Third-Party Microcontrollers, and Chapter 11, Final Project.

An LED for Chapter 7, Exploring the Raspberry Pi's GPIO pins and Chapter 11, Final Project.

1.6K, 3.3k Ohm resistor for Chapter 10, Integrating with Third-Party Microcontrollers.

270 Ohm resistor for Chapter 7, Exploring the Raspberry Pi's GPIO pins and Chapter 11, Final Project.

USB hard drive for Chapter 5, Expanding on Storage Options.

Cooking Hacks Raspberry Pi to Arduino Bridge Shield or Pi Cobbler. These are optional and not necessary, as the breadboard can replace these.

Breadboard. Only required if not using a third-party shield. Needed for Chapter 7, Exploring the Raspberry Pi's GPIO pins, Chapter 10, Integrating with Third-Party Microcontrollers, and Chapter 11, Final Project.

Arduino Uno. Needed for Chapter 10, Integrating with Third-Party Microcontrollers.

USB cable to connect Arduino to Raspberry Pi. Needed for Chapter 10, Integrating with Third-Party Microcontrollers.

Who this book is for

Are you interested in the architecture that forms the Raspberry Pi 2? Would you like to learn how its components work through interactive projects?

This book provides a hands-on guide to the Raspberry Pi 2's hardware and software. Each chapter builds upon the last to develop applications and electronics that leverage many of the features of the Raspberry Pi 2. From programming sound to integrating with third party microcontrollers, it's all covered here.

Aimed at the Raspberry Pi enthusiast, this is a perfect introductory text on how to get the most out of your new device.

While understanding programming concepts is helpful, no prior knowledge of the programming languages covered in this book is required.

Some simple electronics projects are included but no soldering is required.

Conventions

In this book, you will find a number of text styles that distinguish between different kinds of information. Here are some examples of these styles and an explanation of their meaning.

Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: The cd command allows you to change directories.

A block of code is set as follows:

int main(void)

{

int a;

printf(Please input an integer: );

scanf(%d, &a);

printf(You entered the number: %d\n, a);

return 0;

}

Any command-line input or output is written as follows:

mv /home/pi/test.txt /home/pi/test2.txt

New terms and important words are shown in bold. Words that you see on the screen, for example, in menus or dialog boxes, appear in the text like this: Click on the Generate button.

Note

Warnings or important notes appear in a box like this.

Tip

Tips and tricks appear like this.

Reader feedback

Feedback from our readers is always welcome. Let us know what you think about this book—what you liked or disliked. Reader feedback is important for us as it helps us develop titles that you will really get the most out of.

To send us general feedback, simply e-mail <[email protected]>, and mention the book's title in the subject of your message.

If there is a topic that you have expertise in and you are interested in either writing or contributing to a book, see our author guide at www.packtpub.com/authors.

Customer support

Now that you are the proud owner of a Packt book, we have a number of things to help you to get the most from your purchase.

Downloading the example code

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Errata

Although we have taken every care to ensure the accuracy of our content, mistakes do happen. If you find a mistake in one