Arduino Datasheet

8/17/2019 Arduino Datasheet

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The Uno is a microcontroller board

based on the ATmega328P. It has

14 digital input/output pins (o!hich " can be used as P#$

outputs%& " analog inputs& a 1" $'

)uart cr*stal& a U+, connection& a

po!er -ac& an I+P header and areset button. It contains e0er*thing

needed to support the

microcontroller simpl* connect it to

a computer !ith a U+, cable or

po!er it !ith a Ato adapter orbatter* to get started.. ou can

tiner !ith *our U56 !ithout

!orr*ing too much about doing

something !rong& !orst casescenario *ou can replace the chip

or a e! dollars and start o0er

again.

http://www.atmel.com/images/Atmel-8271-8-bit-AVR-Microcontroller-ATmega48A-48PA-88A-88PA-168A-168PA-328-328P_datasheet_Complete.pdfhttp://www.atmel.com/images/Atmel-8271-8-bit-AVR-Microcontroller-ATmega48A-48PA-88A-88PA-168A-168PA-328-328P_datasheet_Complete.pdfhttp://www.atmel.com/images/Atmel-8271-8-bit-AVR-Microcontroller-ATmega48A-48PA-88A-88PA-168A-168PA-328-328P_datasheet_Complete.pdf


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7Uno7 means one in Italian and !as

chosen to mar the release o

Arduino +ot!are (I% 1.9. TheUno board and 0ersion 1.9 o

Arduino +ot!are (I% !ere the

reerence 0ersions o Arduino& no!

e0ol0ed to ne!er releases. The Unoboard is the irst in a series o U+,

Arduino boards& and the reerence

model or the Arduino platorm or

an e:tensi0e list o current& past or

outdated boards see the Arduinoinde: o boards.

ou can ind here *our board

!arrant* inormations.

https://www.arduino.cc/en/Main/warrantyhttps://www.arduino.cc/en/Main/warranty


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;etting +tarted

ou can ind in the ;etting +tarted

section all the inormation *ou needto conigure *our board& use

the Arduino +ot!are (I%& and

start tiner !ith coding and

electronics.

https://www.arduino.cc/en/Guide/HomePagehttps://www.arduino.cc/en/Guide/HomePagehttps://www.arduino.cc/en/Main/Softwarehttps://www.arduino.cc/en/Guide/HomePagehttps://www.arduino.cc/en/Guide/HomePagehttps://www.arduino.cc/en/Main/Software


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Technical specsMicrocontroller ATmega328P

Operating Voltage 5V

Input Voltage (recommended) 7-12V

Input Voltage (limit) -2!V

"igital I#O Pin$ 1% (o& 'ic proide P*M output)

P*M "igital I#O Pin$

Analog Input Pin$ "+ +urrent per I#O Pin 2! mA

"+ +urrent &or 3,3V Pin 5! mA

la$ Memor. 32 /0 (ATmega328P)o& 'ic !,5 /0 u$ed . ootloader

AM 2 /0 (ATmega328P)

44POM 1 /0 (ATmega328P)

+loc peed 1 M6

engt 8, mm

*idt 53,% mm

*eigt 25 g

http://www.atmel.com/Images/doc8161.pdfhttp://www.atmel.com/Images/doc8161.pdf


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Documentation

Programming The Uno can be programmed with

the Arduino Software (IDE). Select

Arduino!"enuino Uno from the

Tools # $oard menu (according to

the microcontroller on %our board).

&or details' see

the reference and tutorials.

The ATmega* on the Uno comes

preprogrammed witha bootloader that allows %ou to

upload new code to it without the

use of an e+ternal hardware

programmer. It communicates usingthe original ST,- protocol

(reference' / header 0les).

https://www.arduino.cc/en/Main/Softwarehttps://www.arduino.cc/en/Reference/HomePagehttps://www.arduino.cc/en/Tutorial/HomePagehttps://www.arduino.cc/en/Hacking/Bootloader?from=Tutorial.Bootloaderhttp://www.atmel.com/Images/doc2525.pdfhttp://www.atmel.com/dyn/resources/prod_documents/avr061.ziphttps://www.arduino.cc/en/Main/Softwarehttps://www.arduino.cc/en/Reference/HomePagehttps://www.arduino.cc/en/Tutorial/HomePagehttps://www.arduino.cc/en/Hacking/Bootloader?from=Tutorial.Bootloaderhttp://www.atmel.com/Images/doc2525.pdfhttp://www.atmel.com/dyn/resources/prod_documents/avr061.zip


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1ou can also b%pass the bootloader

and program the microcontroller

through the I/SP (In2/ircuit SerialProgramming) header using Arduino

ISP or similar3 see these

instructions for details.

The ATmega45U (or *U in there64 and re6 boards) 0rmware

source code is a6ailable in the

Arduino repositor%. The

ATmega45U!*U is loaded with a

D&U bootloader' which can be

acti6ated b%7

• 8n 9e64 boards7 connecting the

solder :umper on the bac; of the

board (near the map of Ital%) andthen rese ing the *U.

https://www.arduino.cc/en/Main/ArduinoISPhttps://www.arduino.cc/en/Main/ArduinoISPhttps://www.arduino.cc/en/Hacking/Programmerhttps://www.arduino.cc/en/Hacking/Programmerhttps://www.arduino.cc/en/Main/ArduinoISPhttps://www.arduino.cc/en/Main/ArduinoISPhttps://www.arduino.cc/en/Hacking/Programmerhttps://www.arduino.cc/en/Hacking/Programmer


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• 8n 9e6 or later boards7 there is

a resistor that pulling the *U!45U


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Although most computers pro6ide

their own internal protection' the

fuse pro6ides an e+tra la%er ofprotection. If more than - mA is

applied to the US$ port' the fuse

will automaticall% brea; the

connection until the short oro6erload is remo6ed.

DiBerences with other boards

The Uno diBers from all preceding

boards in that it does not use the

&TDI US$2to2serial dri6er chip.Instead' it features the Atmega45U

(Atmega*U up to 6ersion 9)


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programmed as a US$2to2serial

con6erter.

Power

The Uno board can be powered 6ia

the US$ connection or with an

e+ternal power suppl%. The powersource is selected automaticall%.

E+ternal (non2US$) power can come

either from an A/2to2D/ adapter

(wall2wart) or batter%. The adaptercan be connected b% plugging a

.4mm center2positi6e plug into the

board>s power :ac;. ?eads from a

batter% can be inserted in the "CD

and in pin headers of the P8=E9

connector.


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The board can operate on an

e+ternal suppl% from 5 to 6olts. If

supplied with less than 'howe6er' the - pin ma% suppl%

less than 06e 6olts and the board

ma% become unstable. If using more

than 4' the 6oltage regulator ma%o6erheat and damage the board.

The recommended range is to 4

6olts.

The power pins are as follows7

• in. The input 6oltage to the Uno

board when it>s using an e+ternal

power source (as opposed to - 6olts

from the US$ connection or otherregulated power source). 1ou can

suppl% 6oltage through this pin' or'


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if suppl%ing 6oltage 6ia the power

:ac;' access it through this pin.

• -.This pin outputs a regulated

- from the regulator on the board.

The board can be supplied with

power either from the D/ power

:ac; ( 2 4)' the US$ connector(-)' or the IC pin of the board (2

4). Suppl%ing 6oltage 6ia the -

or . pins b%passes the regulator'

and can damage %our board. =e

don>t ad6ise it.

• . A . 6olt suppl% generated

b% the on2board regulator.

@a+imum current draw is - mA.

• "CD. "round pins.

• I89E&. This pin on the Uno board

pro6ides the 6oltage reference with


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which the microcontroller operates.

A properl% con0gured shield can

read the I89E& pin 6oltage andselect the appropriate power source

or enable 6oltage translators on the

outputs to wor; with the - or ..

@emor% The ATmega* has ,$ (with .-

,$ occupied b% the bootloader). It

also has ,$ of S9A@ and 4 ,$ of

EEP98@ (which can be read and

written with the EEP98@ librar%).

Input and 8utput

See the mapping between Arduino

pins and ATmega*P ports. The

mapping for the Atmega*' 45*' and* is identical.

https://www.arduino.cc/en/Reference/EEPROMhttps://www.arduino.cc/en/Reference/EEPROM


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Each of the 4F digital pins on the

Uno can be used as an input or

output'using pin@ode()'digital=rite()'

and digital9ead() functions. The%

operate at - 6olts. Each pin can

pro6ide or recei6e mA asrecommended operating condition

and has an internal pull2up resistor

(disconnected b% default) of 2-;

ohm. A ma+imum of FmA is the

6alue that must not be e+ceeded onan% I!8 pin to a6oid permanent

damage to the microcontroller.

In addition' some pins ha6e

specialiGed functions7

https://www.arduino.cc/en/Reference/PinModehttps://www.arduino.cc/en/Reference/DigitalWritehttps://www.arduino.cc/en/Reference/DigitalReadhttps://www.arduino.cc/en/Reference/PinModehttps://www.arduino.cc/en/Reference/DigitalWritehttps://www.arduino.cc/en/Reference/DigitalRead


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• Serial7 (9) and 4 (T). Used to

recei6e (9) and transmit (T) TT?

serial data. These pins areconnected to the corresponding

pins of the ATmega*U US$2to2TT?

Serial chip.

•

E+ternal Interrupts7 and . These pins can be con0gured to

trigger an interrupt on a low 6alue'

a rising or falling edge' or a change

in 6alue. See the attachInterrupt()

function for details.

• P=@7 ' -' 5' H' 4' and 44.

Pro6ide *2bit P=@ output with the

analog=rite() function.

• SPI7 4 (SS)' 44 (@8SI)' 4

(@IS8)' 4 (S/,). These pins


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support SPI communication using

the SPI librar%.

• ?ED7 4. There is a built2in ?ED

dri6en b% digital pin 4. =hen the

pin is


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There are a couple of other pins on

the board7

• A9E&. 9eference 6oltage for the

analog inputs. Used with

analog9eference().

• 9eset. $ring this line ?8= to

reset the microcontroller. T%picall%

used to add a reset button to

shields which bloc; the one on the

board./ommunication

The Uno has a number of facilities

for communicating with a computer'

another Uno board' or othermicrocontrollers. The ATmega*

pro6ides UA9T TT? (-) serial

communication' which is a6ailable


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on digital pins (9) and 4 (T). An

ATmega45U on the board channels

this serial communication o6er US$and appears as a 6irtual com port to

software on the computer. The 45U

0rmware uses the standard US$

/8@ dri6ers' and no e+ternal dri6eris needed.


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A SoftwareSerial librar% allows serial

communication on an% of the Uno>s

digital pins.

The ATmega* also supports I/

(T=I) and SPI communication. The

Arduino Software (IDE) includes a

=ire librar% to simplif% use of theI/ bus3 see the documentation for

details. &or SPI communication' use

the SPI librar%.

Automatic (Software) 9eset9ather than reuiring a ph%sical

press of the reset button before an

upload' the Uno board is designed

in a wa% that allows it to be reset b%

software running on a connected

computer. 8ne of the hardware Jow

control lines (DT9) of the

https://www.arduino.cc/en/Reference/SoftwareSerialhttps://www.arduino.cc/en/Reference/Wirehttps://www.arduino.cc/en/Reference/SPIhttps://www.arduino.cc/en/Reference/SoftwareSerialhttps://www.arduino.cc/en/Reference/Wirehttps://www.arduino.cc/en/Reference/SPI


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ATmega*U!45U is connected to

the reset line of the ATmega* 6ia

a 4 nanofarad capacitor. =henthis line is asserted (ta;en low)' the

reset line drops long enough to

reset the chip. The Arduino Software

(IDE) uses this capabilit% to allow%ou to upload code b% simpl%

pressing the upload button in the

interface toolbar. This means that

the bootloader can ha6e a shorter

timeout' as the lowering of DT9 canbe well2coordinated with the start of

the upload.

This setup has other implications.

=hen the Uno is connected toeither a computer running @ac 8S

or ?inu+' it resets each time a


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connection is made to it from

software (6ia US$). &or the following

half2second or so' the bootloader isrunning on the Uno. =hile it is

programmed to ignore malformed

data (i.e. an%thing besides an

upload of new code)' it will interceptthe 0rst few b%tes of data sent to

the board after a connection is

opened. If a s;etch running on the

board recei6es one2time

con0guration or other data when it0rst starts' ma;e sure that the

software with which it

communicates waits a second after

opening the connection and beforesending this data.


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The Uno board contains a trace that

can be cut to disable the auto2reset.

The pads on either side of the tracecan be soldered together to re2

enable it. It>s labeled 9ESET2EC.

1ou ma% also be able to disable the

auto2reset b% connecting a 44 ohmresistor from - to the reset line3

see this forum thread for details.

9e6isions

9e6ision of the board has the

following new features7

• 4. pinout7 added SDA and S/?

pins that are near to the A9E& pin

and two other new pins placed nearto the 9ESET pin' the I89E& that

allow the shields to adapt to the

http://forum.arduino.cc/index.php/topic,22974.0.htmlhttp://forum.arduino.cc/index.php/topic,22974.0.html


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6oltage pro6ided from the board. In

future' shields will be compatible

with both the board that uses theA9' which operates with - and

with the Arduino Due that operates

with .. The second one is a not

connected pin' that is reser6ed for

future purposes.

• Stronger 9ESET circuit.

• Atmega 45U replace the *U.

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