Basics of open source embedded development board (

What is a Microcontroller
(µC, MCU)
Computer on a single integrated chip•
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Processor (CPU)
Memory (RAM / ROM / Flash)
I/O ports (USB, I2C, SPI, ADC)
• Common microcontroller families:
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Intel: 4004, 8008, etc.
Atmel: AT and AVR
Microchip: PIC
ARM: (multiple manufacturers)
• Used in:
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Cellphones,
Toys
Household appliances
Cars
Cameras

Arduino Overview
 The Arduino microcontroller is an easy to use yet powerful
single board computer that has gained considerable
traction in the hobby and professional market. The
Arduino is open-source, which means hardware is
reasonably priced and development software is free.
 The Arduino project was started in Italy to develop low cost
hardware for interaction design.
 The Arduino hardware comes in several flavors. In the
United States, Sparkfun (www.sparkfun.com) is a good
source for Arduino hardware.
 With the Arduino board, you can write programs and
create interface circuits to read switches and other sensors,
and to control motors and lights with very little effort.

Continue
 The Arduino programming language is a simplified version of
C/C++. If you know C, programming the Arduino will be
familiar. If you do not know C, no need to worry as only a few
commands are needed to perform useful functions. An
important feature of the Arduino is that you can create a control
program on the host PC, download it to the Arduino and it will
run automatically. Remove the USB cable connection to the PC,
and the program will still run from the top each time you push
the reset button. Remove the battery and put the Arduino board
in a closet for six months. When you reconnect the battery, the
last program you stored will run. This means that you connect
the board to the host PC to develop and debug your program,
but once that is done, you no longer need the PC to run the
program.

The ATmega328P Microcontroller
(used by the Arduino)
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•
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AVR 8-bit RISC architecture
Available in DIP package
Up to 20 MHz clock
32kB flash memory
1 kB SRAM
23 programmable I/O
channels
Six 10-bit ADC inputs
Three timers/counters
Six PWM outputs
•
•
•

What is Arduino Not?
•
•
•
•
•
It
It
It
It
It
is
is
is
is
is
not
not
not
not
not
a
a
a
a
a
chip (IC)
board (PCB)
company or a manufacturer
programming language
computer architecture
(although it involves all of these things...)

So what is Arduino?
It’s a movement, not a microcontroller:
• Founded by Massimo Banzi and David
Cuartielles in 2005
Based on “Wiring Platform”, which dates
2003
Open-source hardware platform
Open source development environment
• to
•
•
– Easy-to learn language and libraries (based
on Wiring language)
Integrated development environment (based
on Processing programming environment)
Available for Windows / Mac / Linux
–
–

What is Arduino?
Arduino is a popular “open source” single board
microcontroller. It is designed to make the process of
using electronics in multidisciplinary projects more
accessible.
This idea began in Italy and its initial
purpose was to make STUDENT design
projects more affordable than other
prototyping projects at the time.

Continue…
 Open Source Hardware, you can make your own
board, or buy one.
 Cheap, easily available.
 Open Source Software.
 Very widespread, many projects openly available.
 Extra HW (shields) available.

The Many Flavors of Arduino
•
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•
•
•
•
•
•
Arduino
Arduino
Arduino
Arduino
Arduino
Arduino
Arduino
Arduino
Uno
Leonardo
LilyPad
Mega
Nano
Mini
Mini Pro
BT

Arduino-like Systems
•
•
•
Cortino (ARM)
Xduino (ARM)
LeafLabs Maple
(ARM)
BeagleBoard (Linux)
Wiring Board
(Arduino
predecessor)
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•

Arduino Add-ons (Shields)
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TFT Touch Screen
Data logger
Motor/Servo shield
Ethernet shield
Audio wave shield
Cellular/GSM shield
WiFi shield
...many more

Where to Get an Arduino Board
• Purchase from
worldwide)
online vendor (available
–
–
–
...
Sparkfun
Adafruit
DFRobot
or build your• own
– PC board
– Solderless breadboard http://itp.nyu.edu/physcomp/Tutorials/ArduinoBreadboard

Different types of Arduinos
Arduino Mega 2560
Arduino LilyPad
Arduino Uno
DIY Arduino
Boarduino Kit

Other Hardware Choices-Sheilds
 Xbee Shield
The Xbee shield allows an Arduino board to communicate wirelessly using
Zigbee. The module can communicate up to 100 feet indoors or 300 feet outdoors (with
line-of-sight). It can be used as a serial/usb replacement or you can put it into a
command mode and configure it for a variety of broadcast and mesh networking options.
The Xbee shield was created in collaboration with Libelium, who developed it
for use in their SquidBee motes (used for creating sensor networks).
 Adafruit Servo/Stepper/DC Motor shield
A shield that can control 2 hobby servos and up to 2 unipolar/bipolar stepper
motors or 4 bi-directional DC motors.
 Battery Shield
A shield from Liquidware that connects to the back of the Arduino, with a USB-
rechargable lithium ion battery that can power an Arduino for 14-28 hours depending on
the circuit
 Liquidware TouchShield
OLED touch screen shield.

Continue
 Adafruit Wave shield
Plays any size 22KHz audio files from an SD memory card
for music, effects and interactive sound art
 Adafruit GPS & Datalogging shield
Connects up a GPS module and can log location, time/date
as well as sensor data to an SD memory flash card.
 Adafruit XPort/Ethernet shield
Allows use of an XPort module for connecting to the Internet
as a client or server.

Continue…
 Liquidware TouchShield
OLED touch screen shield.
 Adafruit Servo/Stepper/DC Motor shield
A shield that can control 2 hobby servos and up to 2
unipolar/bipolar stepper motors or 4 bi-directional DC
motors.

Basics of open source embedded development board (

Pins on Arduino
Starting clockwise from the top center:
 Analog Reference pin (orange)
 Digital Ground (light green)
 Digital Pins 2-13 (green)
 Digital Pins 0-1/Serial In/Out - TX/RX (dark green) - These pins cannot be used
for digital i/o (digitalRead and digitalWrite) if you are also using serial
communication (e.g. Serial.begin).
 Reset Button - S1 (dark blue)
 In-circuit Serial Programmer (blue-green)
 Analog In Pins 0-5 (light blue)
 Power and Ground Pins (power: orange, grounds: light orange)
 External Power Supply In (9-12VDC) - X1 (pink)
 Toggles External Power and USB Power (place jumper on two pins closest to
desired supply) - SV1 (purple)
 USB (used for uploading sketches to the board and for serial communication
between the board and the computer; can be used to power the board) (yellow)

Digital Pins
 In addition to the specific functions listed below, the
digital pins on an Arduino board can be used for
general purpose input and output via the pinMode(),
digitalRead(), and digitalWrite() commands. Each pin
has an internal pull-up resistor which can be turned on
and off using digitalWrite() (w/ a value of HIGH or
LOW, respectively) when the pin is configured as an
input. The maximum current per pin is 40 mA.

 Serial: 0 (RX) and 1 (TX). Used to receive (RX) and transmit (TX) TTL
serial data. On the Arduino Diecimila, these pins are connected to the
corresponding pins of the FTDI USB-to-TTL Serial chip. On the
Arduino BT, they are connected to the corresponding pins of the WT11
Bluetooth module. On the Arduino Mini and LilyPad Arduino, they are
intended for use with an external TTL serial module (e.g. the Mini-USB
Adapter).
 External Interrupts: 2 and 3. These pins can be configured to trigger
an interrupt on a low value, a rising or falling edge, or a change in value.
See the attachInterrupt() function for details.
 PWM: 3, 5, 6, 9, 10, and 11. Provide 8-bit PWM output with the
analogWrite() function. On boards with an ATmega8, PWM output is
available only on pins 9, 10, and 11.
 Reset: 7. (Arduino BT-only) Connected to the reset line of the
bluetooth module.
 SPI: 10 (SS), 11 (MOSI), 12 (MISO), 13 (SCK). These pins support SPI
communication, which, although provided by the underlying
hardware. It allow serial communication with another interface by
connecting it serially.
 LED: 13. On the Diecimila and LilyPad, there is a built-in LED
connected to digital pin 13. When the pin is HIGH value, the LED is on,
when the pin is LOW, it's off.

Analog Pins
In addition to the specific functions listed below,
the analog input pins support 10-bit analog-to-digital
conversion (ADC) using the analogRead() function.
Most of the analog inputs can also be used as digital
pins: analog input 0 as digital pin 14 through analog
input 5 as digital pin 19. Analog inputs 6 and 7
(present on the Mini and BT) cannot be used as digital
pins.
 I2C: 4 (SDA) and 5 (SCL). Support I2C (TWI)
communication using the Wire library

Power Pins
 VIN (sometimes labelled "9V"). The input voltage to the Arduino
board when it's using an external power source (as opposed to 5
volts from the USB connection or other regulated power source).
You can supply voltage through this pin, or, if supplying voltage
via the power jack, access it through this pin. Note that different
boards accept different input voltages ranges, please see the
documentation for your board. Also note that the LilyPad has no
VIN pin and accepts only a regulated input.
 5V. The regulated power supply used to power the
microcontroller and other components on the board. This can
come either from VIN via an on-board regulator, or be supplied
by USB or another regulated 5V supply.
 3V3. (Diecimila-only) A 3.3 volt supply generated by the on-
board FTDI chip.
 GND. Ground pins.

Other Pins
 AREF. Reference voltage for the analog inputs. It
provide the analog reference voltage for analog to
digital conversion
 Reset. (Diecimila-only) Bring this line LOW to reset
the microcontroller. Typically used to add a reset
button to shields which block the one on the board.

Function of Each block
 USB Plug: By using this plug we can download hex file of
our program by connecting it with PC. It also provide
supply to arduino board. This USB plug is connected with
FTDI Chip internally
 FTDI Chip: This chip is nothing but voltage level converter
chip. This chip is used to convert USB voltage level to TTL
level and vice versa.
 Digital I/O and PWM section: This section is used as for
general purpose input output usage. By using this section
we can perform digital input and output functions. In this
section some pins are also used as PWM output pins. It is
used for PWM based application like servo motors.

Continue…
 Serial Tx and Rx Section: These two pins are used for serial
communication in arduino. It is internally connected with USB
plug through FTDI chip.
 Power Supply: Power supply section provide different voltage
level to different part of arduino board. This part contain bridge
rectifier and voltage regulator.
 AVR Atmega CPU: This block is the heart of the controller.
Generally Atmega 8, Atmega 16, Atmega 32, Atmega 328
controller are used in arduino board. This block execute all the
fuctions that written in arduino program.
 SPI Interface section: This section is used for serial peripheral
interfacing.
 Power Pins section: This section include various voltage level
pins including ground pins.
 Analog input section: We know that Atmega 8 CPU has
inbuilt 6 channel 10 – bit ADC. This ADC can convert analog
data from analog pin into digital. So, for taking analog value for
digital conversion we have to use this section.

Comments
• Comments can be anywhere
• Comments created with // or /* and */
• // is used for single line comment.
• /* */ is used for multiline
comments
• Comments do not affect code
• You may not need comments, but
think about the community!

//- Single line comment
/* */ - Multiline comment
{ } – used to define a block of code that starts and ends.
; - used to define the end of a line of code.
Programming Symbols

Math Operators
= (assignment) makes something equal to something else. For example,
x = 10*2, thus x = 20.
% (modulo) – this gives the remainder when one number is divided by
another. For example 12 % 10 gives 2.
+ (addition)
- (subtraction)
* (multiplication)
/ (division)

Comparison Operators
These are used to make logical comparisons.
== (equal to) - For example 12==10 is FALSE and 12 ==12 is
TRUE.
!= (not equal to) - For example 12!=10 is TRUE and 12!=12 is
FALSE.
< (less than)
> (greater than)

Control Structures
These execute code based on CONDITIONS. Here are
just a few.
if(condition) { }
else if (condition) { }
else(condition) { }
This will execute the code between the curly braces if the condition
is true, and if not test the condition of the “else if”. If that is false ,
the “else” code will execute.
for (int i =0; i < #repeats; i ++) { }
Used when you would like to repeat a line of code a specific # of times. Often
called a FOR LOOP.

Activity 1: LED Blink
• Load the “Blink” example
(FileExamplesBasicsBlink)
Use pin 13 as digital output
Set output high (+5V)
Wait 1000 milliseconds
Set output low (0V)
•
•
Compile, then upload the program
Congratulations! you are now blinkers!
void setup() {
// initialize the digital pin as an output.
// Pin 13 has an LED connected on most Arduino boards:
pinMode(13, OUTPUT);
}
void loop() {
digitalWrite(13, HIGH); // set the LED on
delay(1000); // wait for a second
digitalWrite(13, LOW); // set the LED off
delay(1000); // wait for a second
}

Now connect your own LED
Anatomy of an LED:
Notes:
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Resistor is needed to limit current
Resistor and LED may be
interchanged
(but polarity of LED is important)
Pin 13 is special: has built-in
resistor and LED
Change program and upload
http://www.wikipedia.org/ •
•

Aside: Using a Solderless
Breadboard
Connected together
300 mils
Connected together

Example: Using a Solderless
Breadboard

Experimenting
• Change the blink rate
– how fast can the LED blink (before you
no longer perceive the blinking?)
can
• How would you make the LED dimmer?
– (...without changing the resistor?)

Digital Input: Reading
and Buttons
Switches
Writing HIGH to an input pin:
enables an internal pull-up
resistor
•
•
•
Turn on/off LED based on switch
Pin 12 reads
Pin 12 reads
LOW when switch is closed
HIGH when switch is open (pull-up)
Without the internal pull-up resistor,
unconnected digital inputs
could read either high or low
void setup() {
pinMode(11, OUTPUT); // Use pin 11 for digital out
pinMode(12, INPUT); // Use pin 12 for digital input
digitalWrite(12, HIGH); // Enable pull‐up resistor
}
void loop() {
boolean state;
state = digitalRead(12); // read state of pin 12
digitalWrite(11, state); // set state of pin 11 (LED)
delay(100); // wait for a 1/10 second
}

Activity 2: Seven-Segment
Display
Write a that program that counts from 0
9 and displays the result on a seven-
segment LED display
• to
• Consider writing a function:
void writeDigit(int n)
that writes a single digit

Seven-Segment Display Table
Useful:
• bitRead(x,n)
Get the value of the
Example:
nth bit of an integer x
– bitRead(0x7E,7); // returns 1 (see table above)
Digit ABCDEFG A B C D E F G
0 0×7E on on on on on on off
1 0×30 off on on off off off off
2 0×6D on on off on on off on
3 0×79 on on on on off off on
4 0×33 off on on off off on on
5 0×5B on off on on off on on
6 0×5F on off on on on on on
7 0×70 on on on off off off off
8 0×7F on on on on on on on
9 0×7B on on on on off on on

•
•
Serial Communication - Writing
IMPORTANT:
USB serial
communication is
shared with
Arduino pins 0
and 1 (RX/TX)
Initialize serial
rate)
Example:
port for communication (and sets baud
Note: Serial.end()
command is usually
unnecessary, unless you need
to use pins 0 & 1
– Serial.begin(9600); // 9600 baud
Format can be:
BIN, HEX, OCT,
or an integer
specifying the
number of digits
to display
Prints data to the serial
Examples:
port
–
–
–
–
Serial.print(“Hi”);
Serial.print(78);
Serial.print(variable);
Serial.print(78,BIN);
//
//
//
//
print
works
works
a string
with
with
numbers, too
variables
1001110will print
•
Same as Serial.print(), but with line-feed
Serial.println(val)
Serial.print(val), Serial.print(val,fmt)
Serial.begin(baud)

Activity 3: Hello World!
Serial Monitor:
• Write an Arduino
program that prints the
message “Hello world”
to the serial port
...whenever you press
a switch/button
Use the Serial Monitor
to see the output
(Ctrl-Shift-M)
Try increasing baud
rate
•
•
•
Make sure this agrees with your
program, i.e.,
Serial.begin(9600);

Program for serial transmission

Serial Communication - Reading
•
Returns the number of bytes
Example:
if (Serial.available() > 0)
data = Serial.read();
}
available to be read, if any
{
To read data from serial port:
•
•
•
•
letter = Serial.read()
letters = Serial.readBytesUntil(character, buffer, length)
number = Serial.parseInt()
number = Serial.parseFloat()
Serial.available()

Basics of open source embedded development board (

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