Raspberry Pi A User manual
Raspberry Pi®
User Guide
2nd Edition
Raspberry Pi®
User Guide
2nd Edition
Eben Upton and Gareth Halfacree
is edition rst published 2014
© 2014 Eben Upton and Gareth Halfacree
Registered oce
John Wiley & Sons Ltd., e Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, United Kingdom
For details of our global editorial oces, for customer services and for information about how to apply for permission to
reuse the copyright material in this book please see our website at www.wiley.com.
e right of the authors to be identied as the authors of this work has been asserted in accordance with the Copyright,
Designs and Patents Act 1988.
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form
or by any means, electronic, mechanical, photocopying, recording or otherwise, except as permitted by the UK Copyright,
Designs and Patents Act 1988, without the prior permission of the publisher.
Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in
electronic books.
Designations used by companies to distinguish their products are often claimed as trademarks. All brand names and prod-
uct names used in this book are trade names, service marks, trademarks or registered trademarks of their respective own-
ers. e publisher is not associated with any product or vendor mentioned in this book. is publication is designed to
provide accurate and authoritative information in regard to the subject matter covered. It is sold on the understanding that
the publisher is not engaged in rendering professional services. If professional advice or other expert assistance is required,
the services of a competent professional should be sought.
Trademarks: Wiley and the Wiley logo are trademarks or registered trademarks of John Wiley & Sons, Inc. and/or its
aliates in the United States and/or other countries, and may not be used without written permission. Raspberry Pi and
the Raspberry Pi logo are registered trademarks of the Raspberry Pi Foundation. All other trademarks are the property of
their respective owners. John Wiley & Sons, Ltd. is not associated with any product or vendor mentioned in the book.
Google Drive™ is a registered trademark of Google™.
A catalogue record for this book is available from the British Library.
ISBN 978-1-118-79548-4 (Pbk); ISBN 978-1-118-79546-0 (ePDF); ISBN 978-1-118-79547-7 (ePub)
Set in 10 pt. Chaparral Pro by Indianapolis Composition Services
Printed simultaneously in Great Britain and the United States
Editorial and Production
VP Consumer and Technology
Publishing Director
Michelle Leete
Associate Director–Book Content
Management
Martin Tribe
Associate Publisher
Chris Webb
Executive Commissioning Editor
Craig Smith
Senior Project Editor
Sara Shlaer
Copy Editor
Kathryn Duggan, Grace Fairley
Technical Editors
Omer Kilic
Mike Cook
Russell Davis
Editorial Manager
Jodi Jensen
Editorial Assistant
Annie Sullivan
Marketing
Associate Marketing Director
Louise Breinholt
Marketing Manager
Lorna Mein
Marketing Assistant
Polly omas
Composition Services
Compositor
Erin Zeltner
Proofreader
Wordsmith Editorial
Indexer:
Potomac Indexing, LLC
Publisher’s Acknowledgements
Some of the people who helped bring this book to market include the following:
For Liz, who made it all possible.
—Eben
For my father, the enthusiastic past,
and my daughter, the exciting future.
—Gareth
About the Authors
Eben Upton is a founder and trustee of the Raspberry Pi Foundation, and serves as its
Executive Director. He is responsible for the overall software and hardware architecture of
the Raspberry Pi, and for the Foundation’s relationships with its key suppliers and custom-
ers. In an earlier life, he founded two successful mobile games and middleware companies,
Ideaworks 3d Ltd. and Podfun Ltd., and held the post of Director of Studies for Computer
Science at St John’s College, Cambridge. He holds a BA, a PhD and an MBA from the
University of Cambridge.
In his day job, Eben works for Broadcom as an ASIC architect and general troublemaker.
Gareth Halfacree is a freelance technology journalist and the co-author of the Raspberry Pi
User Guide alongside project co-founder Eben Upton. Formerly a system administrator working
in the education sector, Gareth’s passion for open source projects has followed him from one
career to another, and he can often be seen reviewing, documenting or even contributing to
projects including GNU/Linux, LibreOce, Fritzing and Arduino. He is also the creator of
the Sleepduino and Burnduino open hardware projects, which extend the capabilities of the
Arduino electronics prototyping system. A summary of his current work can be found at
http://freelance.halfacree.co.uk.
Table of Contents
Introduction ......................................... 1
Programming Is Fun! .........................................................1
A Bit of History ..............................................................3
So What Can You Do with the Raspberry Pi? .....................................8
Part I: Connecting the Board
CHAPTER 1
Meet the Raspberry Pi ................................. 13
A Trip Around the Board .....................................................14
Model A ...................................................................16
Model B ...................................................................17
A History of Model B PCB Revisions ...........................................18
Revision 1 ...............................................................18
Revision 2 ...............................................................18
A Bit of Background .........................................................18
ARM versus x86..........................................................19
Windows versus Linux ....................................................20
CHAPTER 2
Getting Started with the Raspberry Pi ...................... 21
Connecting a Display ........................................................22
Composite Video .........................................................22
HDMI Video .............................................................23
DSI Video ...............................................................24
Connecting Audio ...........................................................24
Connecting a Keyboard and Mouse ............................................25
Installing NOOBS on an SD Card..............................................27
Connecting External Storage..................................................28
Connecting the Network .....................................................29
Wired Networking ........................................................30
Wireless Networking......................................................31
Connecting Power ........................................................32
Installing the Operating System...............................................33
Installing Using NOOBS...................................................33
Installing Manually .......................................................35
xRASPBERRY PI USER GUIDE, 2ND EDITION
CHAPTER 3
Linux System Administration ............................ 41
Linux: An Overview .........................................................42
Linux Basics ................................................................44
Introducing Raspbian........................................................45
About Raspbian’s Parent, Debian ...........................................49
Alternatives to Raspbian. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Using External Storage Devices ...............................................50
Creating a New User Account .................................................51
File System Layout ..........................................................52
Logical Layout ...........................................................53
Physical Layout ..........................................................54
Installing and Uninstalling Software ...........................................55
Obtaining Software from the Pi Store .......................................55
Obtaining Software from Elsewhere.........................................57
Finding the Software You Want ............................................58
Installing Software........................................................59
Uninstalling Software .....................................................61
Upgrading Software.......................................................61
Shutting the Pi Down Safely ..................................................62
CHAPTER 4
Troubleshooting..................................... 63
Keyboard and Mouse Diagnostics .............................................64
Power Diagnostics...........................................................65
Display Diagnostics .........................................................67
Boot Diagnostics ............................................................68
Network Diagnostics ........................................................68
e Emergency Kernel .......................................................71
CHAPTER 5
Network Conguration................................. 73
Wired Networking ..........................................................74
Wireless Networking ........................................................77
Installing Firmware .......................................................78
Connecting to a Wireless Network via wpa_gui ...............................82
Connecting to a Wireless Network via the Terminal ...........................85
xi
TABLE OF CONTENTS
CHAPTER 6
The Raspberry Pi Software Conguration Tool ................ 93
Running the Tool ...........................................................94
e Setup Options Screen ....................................................95
1 Expand Filesystem ......................................................95
2 Change User Password. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
3 Enable Boot to Desktop..................................................96
4 Internationalisation Options .............................................97
5 Enable Camera .........................................................99
6 Add to Rastrack.........................................................99
7 Overclock.............................................................100
8 Advanced Options .....................................................101
9 About raspi-cong .....................................................105
CHAPTER 7
Advanced Raspberry Pi Conguration..................... 107
Editing Conguration Files via NOOBS .......................................108
Hardware Settings—cong.txt ...............................................110
Modifying the Display....................................................111
Boot Options ...........................................................114
Overclocking the Raspberry Pi.............................................114
Disabling L2 Cache .........................................................118
Enabling Test Mode .....................................................119
Memory Partitioning .......................................................119
Software Settings—cmdline.txt ..............................................120
Part II: Building a Media Centre, Productivity Machine
or Web Server
CHAPTER 8
The Pi as a Home Theatre PC........................... 125
Playing Music at the Console ................................................126
Dedicated HTPC with Raspbmc ..............................................128
Streaming Internet Media ................................................129
Streaming Local Network Media...........................................131
Conguring Raspbmc ....................................................133
xii RASPBERRY PI USER GUIDE, 2ND EDITION
CHAPTER 9
The Pi as a Productivity Machine ........................ 135
Using Cloud-Based Apps ....................................................136
Using LibreOce ..........................................................139
Image Editing with e Gimp ................................................141
CHAPTER 10
The Pi as a Web Server............................... 145
Installing a LAMP Stack.....................................................146
Installing WordPress .......................................................150
Part III: Programming with the Raspberry Pi
CHAPTER 11
An Introduction to Scratch............................. 157
Introducing Scratch ........................................................158
Example 1: Hello World .....................................................159
Example 2: Animation and Sound ............................................162
Example 3: A Simple Game ..................................................165
Robotics and Sensors .......................................................171
Sensing with the PicoBoard ...............................................171
Robotics with LEGO .....................................................171
Further Reading ...........................................................172
CHAPTER 12
An Introduction to Python............................. 173
Introducing Python ........................................................174
Example 1: Hello World .....................................................174
Example 2: Comments, Inputs, Variables and Loops ............................180
Example 3: Gaming with pygame .............................................184
Example 4: Python and Networking ..........................................193
Further Reading ...........................................................199
xiii
TABLE OF CONTENTS
Part IV: Hardware Hacking
CHAPTER 13
Learning to Hack Hardware ............................ 203
Electronic Equipment.......................................................204
Reading Resistor Colour Codes...............................................206
Sourcing Components ......................................................208
Online Sources ..........................................................208
Oine Sources..........................................................209
Hobby Specialists........................................................209
Moving Up From the Breadboard.............................................210
A Brief Guide to Soldering ...................................................213
CHAPTER 14
The GPIO Port ..................................... 219
Identifying Your Board Revision..............................................220
GPIO Pinout Diagrams......................................................220
GPIO Features .............................................................222
UART Serial Bus.........................................................222
I2C Bus.................................................................223
SPI Bus ................................................................223
Using the GPIO Port in Python ..............................................223
GPIO Output: Flashing an LED............................................224
GPIO Input: Reading a Button.............................................228
CHAPTER 15
The Raspberry Pi Camera Module........................ 233
Why Use the Camera Module? ...............................................234
Installing the Camera Module................................................235
Enabling Camera Mode .....................................................238
Capturing Stills ............................................................239
Recording Video ...........................................................242
Command-Line Time-Lapse Photography .....................................243
xiv RASPBERRY PI USER GUIDE, 2ND EDITION
CHAPTER 16
Add-on Boards..................................... 249
Ciseco Slice of Pi ...........................................................250
Adafruit Prototyping Pi Plate ................................................254
Fen Logic Gertboard ........................................................257
Part V: Appendixes
APPENDIX A
Python Recipes..................................... 265
Raspberry Snake (Chapter 12, Example 3) .....................................266
IRC User List (Chapter 12, Example 4) ........................................268
GPIO Input and Output (Chapter 14) .........................................270
APPENDIX B
Camera Module Quick Reference ........................ 271
Shared Options ............................................................272
Raspistill Options ..........................................................275
Raspivid Options...........................................................276
Raspiyuv Options ..........................................................276
APPENDIX C
HDMI Display Modes................................. 277
Index............................................ 283
Introduction
“CHILDREN TODAY ARE digital natives”, said a man I got talking to at a reworks party
last year. “I don’t understand why you’re making this thing. My kids know more about set-
ting up our PC than I do.”
I asked him if they could program, to which he replied: “Why would they want to? e com-
puters do all the stu they need for them already, don’t they? Isn’t that the point?”
As it happens, plenty of kids today aren’t digital natives. We have yet to meet any of these
imagined wild digital children, swinging from ropes of twisted-pair cable and chanting war
songs in nicely parsed Python. In the Raspberry Pi Foundation’s educational outreach work, we
do meet a lot of kids whose entire interaction with technology is limited to closed platforms
with graphical user interfaces (GUIs) that they use to play movies, do a spot of word-processed
homework and play games. ey can browse the web, upload pictures and video, and even
design web pages. (ey’re often better at setting the satellite TV box than Mum or Dad, too.)
It’s a useful toolset, but it’s shockingly incomplete, and in a country where 20 percent of house-
holds still don’t have a computer in the home, even this toolset is not available to all children.
Despite the most fervent wishes of my new acquaintance at the reworks party, computers
don’t program themselves. We need an industry full of skilled engineers to keep technology
moving forward, and we need young people to be taking those jobs to ll the pipeline as older
engineers retire and leave the industry. But there’s much more to teaching a skill like pro-
grammatic thinking than breeding a new generation of coders and hardware hackers. Being
able to structure your creative thoughts and tasks in complex, non-linear ways is a learned
talent, and one that has huge benets for everyone who acquires it, from historians to
designers, lawyers and chemists.
Programming Is Fun!
It’s enormous, rewarding, creative fun. You can create gorgeous intricacies, as well as (much
more gorgeous, in my opinion) clever, devastatingly quick and deceptively simple-looking
routes through, under and over obstacles. You can make stu that’ll have other people looking
on jealously, and that’ll make you feel wonderfully smug all afternoon. In my day job, where I
design the sort of silicon chips that we use in the Raspberry Pi as a processor and work on the
low-level software that runs on them, I basically get paid to sit around all day playing. What
could be better than equipping people to be able to spend a lifetime doing that?
RASPBERRY PI USER GUIDE, SECOND EDITION
2
It’s not even as if we’re coming from a position where children don’t want to get involved in
the computer industry. A big kick up the backside came a few years ago, when we were mov-
ing quite slowly on the Raspberry Pi project. All the development work on Raspberry Pi was
done in the spare evenings and weekends of the Foundation’s trustees and volunteers—
we’re a charity, so the trustees aren’t paid by the Foundation, and we all have full-time jobs
to pay the bills. is meant that occasionally, motivation was hard to come by when all I
wanted to do in the evening was slump in front of the Arrested Development boxed set with a
glass of wine. One evening, when not slumping, I was talking to a neighbour’s nephew about
the subjects he was taking for his General Certicate of Secondary Education (GCSE, the
British system of public examinations taken in various subjects from the age of about 16),
and I asked him what he wanted to do for a living later on.
“I want to write computer games”, he said.
“Awesome. What sort of computer do you have at home? I’ve got some programming books
you might be interested in.”
“A Wii and an Xbox.”
On talking with him a bit more, it became clear that this perfectly smart kid had never done
any real programming at all; that there wasn’t any machine that he could program in the
house; and that his information and communication technology (ICT) classes—where he
shared a computer and was taught about web page design, using spreadsheets and word pro-
cessing—hadn’t really equipped him to use a computer even in the barest sense. But com-
puter games were a passion for him (and there’s nothing peculiar about wanting to work on
something you’re passionate about). So that was what he was hoping the GCSE subjects he’d
chosen would enable him to do. He certainly had the artistic skills that the games industry
looks for, and his maths and science marks weren’t bad. But his schooling had skirted around
any programming—there were no Computing options on his syllabus, just more of the same
ICT classes, with its emphasis on end users rather than programming. And his home interac-
tions with computing meant that he stood a vanishingly small chance of acquiring the skills
he needed in order to do what he really wanted to do with his life.
is is the sort of situation I want to see the back of, where potential and enthusiasm is
squandered to no purpose. Now, obviously, I’m not monomaniacal enough to imagine that
simply making the Raspberry Pi is enough to eect all the changes that are needed. But I do
believe that it can act as a catalyst. We’re already seeing big changes in the UK schools’ cur-
riculum, where Computing is arriving on the syllabus and ICT is being reshaped, and we’ve
seen a massive change in awareness of a gap in our educational and cultural provision for
kids just in the short time since the Raspberry Pi was launched.
INTRODUCTION 3
Too many of the computing devices a child will interact with daily are so locked down that they
can’t be used creatively as a tool—even though computing is a creative subject. Try using your
iPhone to act as the brains of a robot, or getting your PS3 to play a game you’ve written. Sure,
you can program the home PC, but there are signicant barriers in doing that which a lot of
children don’t overcome: the need to download special software, and having the sort of parents
who aren’t worried about you breaking something that they don’t know how to x. And plenty
of kids aren’t even aware that doing such a thing as programming the home PC is possible. ey
think of the PC as a machine with nice clicky icons that give you an easy way to do the things
you need to do so you don’t need to think much. It comes in a sealed box, which Mum and Dad
use to do the banking and which will cost lots of money to replace if something goes wrong!
e Raspberry Pi is cheap enough to buy with a few weeks’ pocket money, and you probably
have all the equipment you need to make it work: a TV, an SD card that can come from an old
camera, a mobile phone charger, a keyboard and a mouse. It’s not shared with the family; it
belongs to the kid; and it’s small enough to put in a pocket and take to a friend’s house. If
something goes wrong, it’s no big deal—you just swap out a new SD card and your Raspberry
Pi is factory-new again. And all the tools, environments and learning materials that you need
to get started on the long, smooth curve to learning how to program your Raspberry Pi are
right there, waiting for you as soon as you turn it on.
A Bit of History
I started work on a tiny, aordable, bare-bones computer about seven years ago, when I was
a Director of Studies in Computer Science at Cambridge University. I’d received a degree at
the University Computer Lab as well as studying for a PhD while teaching there, and over
that period, I’d noticed a distinct decline in the skillset of the young people who were apply-
ing to read Computer Science at the Lab. From a position in the mid-1990s, when 17-year-
olds wanting to read Computer Science had come to the University with a grounding in
several computer languages, knew a bit about hardware hacking, and often even worked in
assembly language, we gradually found ourselves in a position where, by 2005, those kids
were arriving having done some HTML—with a bit of PHP and Cascading Style Sheets if you
were lucky. ey were still fearsomely clever kids with lots of potential, but their experience
with computers was entirely dierent from what we’d been seeing before.
e Computer Science course at Cambridge includes about 60 weeks of lecture and seminar
time over three years. If you’re using the whole rst year to bring students up to speed, it’s
harder to get them to a position where they can start a PhD or go into industry over the next
two years. e best undergraduates—the ones who performed the best at the end of their
three-year course—were the ones who weren’t just programming when they’d been told to
for their weekly assignment or for a class project. ey were the ones who were programming
RASPBERRY PI USER GUIDE, SECOND EDITION
4
in their spare time. So the initial idea behind the Raspberry Pi was a very parochial one with
a very tight (and pretty unambitious) focus: I wanted to make a tool to get the small number
of applicants to this small university course a kick start. My colleagues and I imagined we’d
hand out these devices to schoolkids at open days, and if they came to Cambridge for an
interview a few months later, we’d ask what they’d done with the free computer we’d given
them. ose who had done something interesting would be the ones that we’d be interested
in having in the program. We thought maybe we’d make a few hundred of these devices, or
best case, a lifetime production run of a few thousand.
Of course, once work was seriously underway on the project, it became obvious that there was
a lot more we could address with a cheap little computer like this. What we started with is a
long way indeed from the Raspberry Pi you see today. I began by soldering up the longest piece
of breadboard you can buy at Maplin with an Atmel chip at our kitchen table, and the rst
crude prototypes used cheap microcontroller chips to drive a standard-denition TV set
directly. With only 512 K of RAM, and a few MIPS of processing power, these prototypes were
very similar in performance to the original 8-bit microcomputers. It was hard to imagine these
machines capturing the imaginations of kids used to modern games consoles and iPads.
ere had been discussions at the University Computer Lab about the general state of com-
puter education, and when I left the Lab for a non-academic job in the industry, I noticed
that I was seeing the same issues in young job applicants as I’d been seeing at the University.
So I got together with my colleagues Dr Rob Mullins and Professor Alan Mycroft (two col-
leagues from the Computer Lab), Jack Lang (who lectures in entrepreneurship at the
University), Pete Lomas (a hardware guru) and David Braben (a Cambridge games industry
leading light with an invaluable address book), and over beers (and, in Jack’s case, cheese and
wine), we set up the Raspberry Pi Foundation—a little charity with big ideas.
Why “Raspberry Pi”?
We get asked a lot where the name “Raspberry Pi” came from. Bits of the name came from
different trustees. It’s one of the very few successful bits of design by committee I’ve seen, and
to be honest, I hated it at rst. (I have since come to love the name, because it works really
well—but it took a bit of getting used to since I’d been calling the project the “ABC Micro” in my
head for years.) It’s “Raspberry” because there’s a long tradition of fruit names in computer
companies (besides the obvious, there are the old Tangerine and Apricot computers—and we
like to think of the Acorn as a fruit as well). “Pi” is a mangling of “Python”, which we thought
early on in development would be the only programming language available on a much less
powerful platform than the Raspberry Pi we ended up with. As it happens, we still recommend
Python as our favourite language for learning and development, but there is a world of other
language options you can explore on the Raspberry Pi too.
Other manuals for A
2
This manual suits for next models
1
Table of contents
Other Raspberry Pi Motherboard manuals
