AREF: Used to provide reference voltage for analog inputs with analogReference() function.

Analog pin 4 (SDA) and pin 5 (SCA) also used for TWI communication using Wire library.Īrduino Uno has a couple of other pins as explained below:.

They measure from 0 to 5 volts but this limit can be increased by using AREF pin with analog Reference() function.

In-built LED Pin 13: This pin is connected with an built-in LED, when pin 13 is HIGH – LED is on and when pin 13 is LOW, its off.Īlong with 14 Digital pins, there are 6 analog input pins, each of which provide 10 bits of resolution, i.e.

SPI Pins 10 (SS), 11 (MOSI), 12 (MISO) and 13 (SCK): These pins are used for SPI communication.

PWM Pins 3, 5, 6, 9 and 11: These pins provide an 8-bit PWM output by using analogWrite() function.

External Interrupt Pins 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.

They are connected with the corresponding ATmega328P USB to TTL serial chip.

Serial Pins 0 (Rx) and 1 (Tx): Rx and Tx pins are used to receive and transmit TTL serial data.

Out of these 14 pins, some pins have specific functions as listed below: Each pin operate at 5V and can provide or receive a maximum of 40mA current, and has an internal pull-up resistor of 20-50 KOhms which are disconnected by default. The 14 digital input/output pins can be used as input or output pins by using pinMode(), digitalRead() and digitalWrite() functions in arduino programming.

Arduino Uno has 14 digital input/output pins (out of which 6 can be used as PWM outputs), 6 analog input pins, a USB connection, A Power barrel jack, an ICSP header and a reset button. Along with ATmega328P, it consists other components such as crystal oscillator, serial communication, voltage regulator, etc. Note: Complete technical information can be found in the Arduino UNO Datasheet, linked at the bottom of this page.Īrduino Nano, Arduino Pro Mini, Arduino Mega, Arduino Due, Arduino MKR1000 Wi-Fi Board, Arduino LeonardoĪrduino Uno is a microcontroller board based on 8-bit ATmega328P microcontroller. To provide reference voltage for input voltage.ĪTmega328P – 8 bit AVR family microcontroller Used to receive and transmit TTL serial data.ġ0 (SS), 11 (MOSI), 12 (MISO) and 13 (SCK) Used to provide analog input in the range of 0-5V Vin: Input voltage to Arduino when using an external power source.ĥV: Regulated power supply used to power microcontroller and other components on the board.ģ.3V: 3.3V supply generated by on-board voltage regulator. Along with ATmega328P MCU IC, it consists other components such as crystal oscillator, serial communication, voltage regulator, etc.

Arduino Uno is a popular microcontroller development board based on 8-bit ATmega328P microcontroller.

Arduino uno r2 datasheet