iRobot COMMAND MODULE User manual

iRobot®Command Module
OWNERS MANUAL
www.irobot.com

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iRobot Command Module Owner’s Manual
Important Safety Instructions
GENERAL SAFETY INSTRUCTIONS
• Read all safety and operating instructions before
operating iRobot Command Module.
• Retain the safety and operating instructions for
future reference.
• Follow all operating and use instructions.
• Refer all non-routine servicing to iRobot.
COMMAND MODULE USE RESTRICTIONS
• The Command Module is for indoor use only.
• Do not sit or stand on this device.
• Keep the switch in the off position, otherwise the Create
robot battery will drain when iRobot Command Module
is on.
• Do not pour or spray water onto iRobot Command Module.
• Do not expose iRobot Command Module to
anything hazardous, or anything that is burning
or smoking.
• iRobot Create has built-in safety sensors to keep it
from falling down stairs and bumping hard into walls.
iRobot is not responsible for any product issues that
may arise if you disable those sensors using the
Command Module.
• Never handle the Command Module with wet hands.
• Only experienced users should attempt to design
and build their own circuitr y.
ePort SAFETY INSTRUCTIONS
The maximum voltage available on the ePort is 21V, so
the ePort pins will not shock you if they contact your skin.
However, the ePort can supply over 20 watts of electrical
power. In the event of an electrical fault, this can generate
enough heat to burn you or star t a fire in the event of an
electrical fault. Only experienced users should attempt to
design and build their own circuitr y.Prebuilt ePort modules
are available from a supplier listed in the Appendix A and
are suitable for users who lack the experience to design
their own circuitr y.
• Always use care when wiring custom circuitry to an ePort.
• Never run your iRobot Create unattended.
• Always fully test your new designs under close supervision.
• Always remove the batter y from Create or remove the
ePort add-on circuitry from Create before handling it.
• Never touch the circuitry with the power turned on.
• Enclose your add-on circuitry so it is not inadvertently
shorted during operation.
• The Vcc and Vpwr supplies are protected by a
self-resetting fuse within Create. If you exceed the
current ratings, power Create off for 30 seconds
to reset the fuse.

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iRobot Command Module Owner’s Manual
Introduction ...........................................................................................5
1.1 Anatomy.........................................................................................5
1.2 Over view ........................................................................................5
1.3 Example applications ......................................................................5
2. Getting Started ..................................................................................6
2.1 Plugging in the Command Module ....................................................6
2.2 Running the preinstalled “drive” demo program ................................6
2.3 Installing the development tools ......................................................7
2.4 Installing the USB serial port ...........................................................8
3. Your First Project ...............................................................................10
3.1 Developing for the Command Module ...............................................10
3.2 Setting up a new project..................................................................10
3.3 Compiling your project.....................................................................11
3.4 Downloading your project over the USB link ......................................12
3.5 Testing the “input” example program................................................13
3.6 Creating your own project ................................................................14
4. Software Reference ............................................................................15
4.1 Declaring and using variables and registers on the ATMega168 .........15
4.2 I/O Pin Basics ................................................................................15
4.3 The Command Module’s connectors ................................................15
4.4 The Digital I/O control registers .......................................................16
4.5 DDRx: Setting the direction of a pin..................................................16
4.6 PORTx: Setting pullups on an input pin .............................................16
4.7 PORTx: Setting the state of an output pin .........................................16
4.8 PINx: Reading the state of an input or output pin ..............................16
4.9 Using bitwise operators to selectively change bit values ....................17
Table of Contents

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iRobot Command Module Owner’s Manual
4.10 Command Module Internal Pins .....................................................17
4.11 Adding a button and LED to the input example program ...................18
4.12 Taking an analog measurement using the ADC................................18
4.13 Using an analog measurement in the light example program............19
4.14 Using a timer................................................................................20
4.15 Debouncing a Button Input ............................................................21
4.16 Setting up and using the serial port ...............................................22
4.17 Using the USB Port for Serial Debugging ........................................23
4.18 Powering Create ...........................................................................23
4.19 Putting the Command Module to Sleep...........................................24
5. Open Interface Reference ...................................................................25
5.1 Starting the Open Interface .............................................................25
5.2 Changing the baud rate ...................................................................25
5.3 Controlling Create’s LEDs................................................................26
5.4 Composing and playing songs..........................................................26
5.5 Moving Create ................................................................................27
5.6 Controlling Create’s low-side power drivers .......................................27
5.7 Sending an Infrared Character .........................................................28
5.8 Reading Create’s sensors ...............................................................28
6.Microcontroller reference.....................................................................29
7. Bootloader reference ..........................................................................30
8. Hardware reference ............................................................................31
8.1 ePort Pinouts .................................................................................31
8.2 ePort I/O connections.....................................................................31
8.3 ePort connection types and interfacing.............................................32
8.4 ePort electrical specifications ..........................................................33
8.5 ePort safety and cautions................................................................33
8.6 Component Suppliers......................................................................34

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iRobot Command Module Owner’s Manual
1Introduction
1.1 Anatomy LED 1
LED 2
Top Left ePort USB Indicator
USB
Hold Down Screws
Soft Button
Reset
Top Center ePort
Power LED
Power Switch
Cargo Bay ePort Top Right ePort
iRobot Create Connector
(under the Command Module)
1.2 Overview
The iRobot Command Module works with iRobot Create,
giving you a way to write your own programs in C or C++
to control Create and to add custom hardware to expand
Create’s capabilities without tethering the robot to a PC.
The Command Module plugs into Create’s Cargo Bay
Connector, and it has four expansion ports that provide
additional inputs and outputs for your custom hardware.
Three of the connectors are on the top surface, spaced
to provide easy attachment points for an array of sensors,
and one connector is on the back for easy access from the
cargo bay.
The Command Module is powered by an Atmel AVR
ATMega168 microcontroller which can be reprogrammed
by downloading programs from your Windows XP computer
with the included USB cable. Your programs can use the
iRobot Open Interface serial protocol to control Create’s
motors, lights, and speaker, and read its sensors. At the
same time, the microcontroller can directly interface with
your own custom hardware through its I/O connections.
Start with one of the example programs and expand and
change it to add your own functionality. Updates and more
information are available at www.irobot.com/create.
This manual assumes intermediate knowledge of the C or
C++ programming languages, including bitwise operators.
If you don’t know either of these languages, pick up a book
on C from a library or bookstore. You can also find a lot of
good reference materials and tutorials online by searching
for “C language” in an internet search engine.
The manual also assumes a basic familiarity with
microcontrollers, including I/O pins, registers, and
interrupts, as well as experience with compilers and
interactive development environments (IDEs).
For more information on how to use the Command Module’s
software capabilities, please see the Software Reference
chapter and the Open Interface reference guide found at
www.irobot.com/create.
1.3 Example applications
Whether you are a hacker, educator, or robotics hobbyist,
the Command Module opens many exciting possibilities.
The applications are limited only by your imagination:
• Teach robotics and programming at high schools or
universities. iRobot Create is a robust, affordable
robotic platform that enables students to each have
their own robot.
• Add new sensors and carry out your own robotics
experiments.
• Create a low-cost swarm of robots to investigate
collective behavior.
• Have fun with robot “art” exhibits, song and dances or
other entertaining behaviors.
• Add a camera and internet connection to create a low
cost sentry robot.

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iRobot Command Module Owner’s Manual
2.1 Plugging in the iRobot Command Module
Turn off Create.
Plug the Command Module into the Create’s Cargo Bay
Connector as shown in Figure 1. Make sure it is firmly
seated.
Command
Module
Cargo Bay
Connector
iRobot Create
Create Figure 1 Inserting the Command Module into Create connector
Tighten the two hold-down screws on either end of the
Command Module with a Phillips head screwdriver, as
shown in Figure 2.
Command Module
Hold-Down Screws
Command Module
iRobot Create
Philips-head
Screwdriver
Create Figure 2 Securing the Command Module with the hold-down screws
2.2 Running the preinstalled “drive” demo program
The Command Module comes pre-installed with a demo
program to let you know that everything is working.
Turn on Create and wait two seconds until Create’s Power
LED stops flashing, which indicates that Create is now
running its main code.
Press the “reset” button on the Command Module and
listen for a series of fast beeps. The LEDs on the Command
Module and Create will blink slowly.
Place Create on the ground and press the black “soft”
button on the Command Module. The robot will play
another song and then start driving around and flashing
its LEDs in sequence, beeping and turning when it bumps
into something. To stop the robot, press the “soft” button
again or pick the robot up.
Troubleshooting:
• After turning on Create, always wait until Create’s Power
LED stops flashing rapidly before starting a Command
Module program.
• Make sure the Command Module is securely seated.
• Make sure that your iRobot Create has a full set of
charged batteries (see Create documentation for more
information on batteries).
• Disconnect the USB cable from the Command Module.
• Ensure that Create’s serial cable is not connected to its
Mini-DIN connector.
2Getting Started

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iRobot Command Module Owner’s Manual
2.3 Installing the development tools
The development tools provided on the included CD-ROM
allow you to create your own Command Module programs.
The Command Module uses the WinAVR set of open-source
development tools to let you write your own programs in
the C or C++ languages. The development tools include
an editor, compiler, and a downloader for loading your
program onto the Command Module. For more information
on WinAVR, please check the project website at
http://winavr.sourceforge.net
To install WinAVR on your Windows XP computer, perform the
steps below. If you have a previous version of WinAVR installed
on your computer, please uninstall it before proceeding.
NOTE: WinAVR places its access paths at the front
of Window’s PATH environment variable. This can cause
conflicts with application that use executables or dlls
that are also in WinAVR (e.g. make.exe; tclsh84.dll).To
fix this, after installing, move WinAVR’s paths to the end
of the PATH environment variable. Open Settings>Control
Panel>System, click on Advanced, click on Environment
Variables, Select Path under System Variables, click on
Edit, move C:\WinAVR\utils\bin and C:\WinAVR\bin
to the end of the list (after a semicolon), and click OK
3 times. On one occasion, installing WinAVR wiped out
the installer’s entire path. For safety, copy the value of
your path variable to a spare text file in case you need to
restore it later.
1. Insert the Command Module product CD into your
computer. Start the WinAVR installation program
(WinAVR-20060421-install.exe) by double-clicking on it.
2. Select your language.
3. Click through the rest of the install screens, accepting
the defaults.
4. The last screen says that WinAVR has been installed
on your computer. The installation is now complete.
Click Finish.

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iRobot Command Module Owner’s Manual
2.4 Installing the USB serial port
To install the drivers for the USB serial port, connect your
Command Module to your PC using the provided USB cable
as shown in Figure 3.
Create Figure 3 Connecting the Command Module to your computer’s USB port
The Command Module should be automatically detected
and the New Hardware Wizard window will pop up.
Select Yes to allow Windows to connect to Windows Update
to find the driver.
Select the Install the software automatically option
It should install the driver and return without errors saying
that the hardware is installed and ready to use.
If the wizard says that it is unable to find the software,
quit the wizard and open the Command Module product
CD. Install the drivers manually by double-clicking on
CDM_Setup_32.exe (if you have 32-bit Windows XP) or
CDM_Setup_64.exe (if you have 64-bit Windows XP).
USB Port on PC
Included USB Cable
USB Port on
Command Module Command Module
iRobot Create

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iRobot Command Module Owner’s Manual
The New Hardware Wizard window will then pop up a
second time, showing that it has found a USB Serial Port.
Repeat the above procedure, again selecting the Install the
software automatically option. Once the driver installation
has completed, click the Finish button and proceed to the
next step.
Next, find the COM port number which was assigned to
the Command Module.
On your PC, go to Start->Settings->Control Panel->System.
Go to the Hardware tab and click the Device Manager
button.
Scroll down and expand the Ports (COM & LPT) category by
clicking on the + sign.
Double click on the USB Serial Port line to launch the
properties window.
Select the Port Settings tab and then click on the
Advanced button.
Change the COM Port Number to COM9 or another unused
port between COM1 and COM9 using the pull-down menu.
Using a high port number will reduce the chances that the
port setting will interfere with other hardware that you may
install on your computer in the future. All of the example
programs assume that you are using COM9. If you use a
COM port other than COM9, you will need to update the
example program’s makefile before you download to the
Command Module. The installation is now complete.

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iRobot Command Module Owner’s Manual
3Your First Project
The example programs are a good place to start using the
Command Module. The program that came preprogrammed
on your Command Module is called drive and its source
code is in the “Sample Projects” directory on the Command
Module Product CD. This chapter will guide you through
compiling and downloading one of the other example programs
named input, and will then give you directions for creating
your own project. The input example program is designed
to demonstrate how to use all of the Command Module’s
input and output capabilities using buttons and LEDs.
3.1 Developing for the Command Module
The Command Module is built around an Atmel AVR
ATMega168 microcontroller. All of the programs that you
write and load onto the Command Module are run on this 8-bit
processor. For more information on the microcontroller,
please see the microcontroller reference section in chapter
7 and the microcontroller spec sheet on the Product CD.
The Command Module uses the WinAVR suite of open
source development tools to compile and download your
C or C++ programs. The WinAVR tools include the GNU
GCC compiler, avrdude downloader, and the Programmers
Notepad IDE.
The WinAVR installer installs a lot of useful documentation
in the C:\WinAVR\doc directory. In the avr-libc sub-directory
you’ll find the avr-libc user’s manual, which has information
on many functions designed for AVR microcontrollers which
you can use in your programs. Another good resource for
developing with AVR microcontrollers and using WinAVR in
particular is the avrfreaks website at http://www.avr freaks.
net. One of the best sources of information on the website
is the forum, where you can find answers to most of your
development questions. Be sure to search the forum
before posting your own question because most common
questions have already been answered already.
3.2 Setting up a new project
In this example, you will set up a new project for the input
example program. The steps are similar for any new project
you create.
1. Get the source files. Make a new directory on your
computer and name it “input.” Copy the files input.c,
oi.h, and makefile from the examples/input directory
on the Command Module CD to this directory. The file
input.c is the main C source code file, oi.h is the Open
Interface header file, and makefile contains instructions
for Programmers Notepad on how to compile and
download the project.
2. Start Programmers Notepad using the desktop shortcut.
If you don’t have the shortcut, find Programmers Notepad
directly at C:\WinAVR\pn\pn.exe (if you used the
default installation directory)
3. Create a new project. In Programmers Notepad, go to
File->New and click on Project.