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Arduino UNO

The Arduino UNO is a standard board of Arduino. Here UNO means 'one' in Italian. It was named as UNO to label the first release of Arduino Software. It was also the first USB board released by Arduino. It is considered as the powerful board used in various projects. developed the Arduino UNO board.

Arduino UNO is based on an ATmega328P microcontroller. It is easy to use compared to other boards, such as the Arduino Mega board, etc. The board consists of digital and analog Input/Output pins (I/O), shields, and other circuits.

The Arduino UNO includes 6 analog pin inputs, 14 digital pins, a USB connector, a power jack, and an ICSP (In-Circuit Serial Programming) header. It is programmed based on IDE, which stands for Integrated Development Environment. It can run on both online and offline platforms.

The IDE is common to all available boards of Arduino.

The Arduino board is shown below:

Arduino UNO

The components of Arduino UNO board are shown below:

Arduino UNO

Let's discuss each component in detail.

  • ATmega328 Microcontroller- It is a single chip Microcontroller of the ATmel family. The processor code inside it is of 8-bit. It combines Memory (SRAM, EEPROM, and Flash), Analog to Digital Converter, SPI serial ports, I/O lines, registers, timer, external and internal interrupts, and oscillator.
  • ICSP pin - The In-Circuit Serial Programming pin allows the user to program using the firmware of the Arduino board.
  • Power LED Indicator- The ON status of LED shows the power is activated. When the power is OFF, the LED will not light up.
  • Digital I/O pins- The digital pins have the value HIGH or LOW. The pins numbered from D0 to D13 are digital pins.
  • TX and RX LED's- The successful flow of data is represented by the lighting of these LED's.
  • AREF- The Analog Reference (AREF) pin is used to feed a reference voltage to the Arduino UNO board from the external power supply.
  • Reset button- It is used to add a Reset button to the connection.
  • USB- It allows the board to connect to the computer. It is essential for the programming of the Arduino UNO board.
  • Crystal Oscillator- The Crystal oscillator has a frequency of 16MHz, which makes the Arduino UNO a powerful board.
  • Voltage Regulator- The voltage regulator converts the input voltage to 5V.
  • GND- Ground pins. The ground pin acts as a pin with zero voltage.
  • Vin- It is the input voltage.
  • Analog Pins- The pins numbered from A0 to A5 are analog pins. The function of Analog pins is to read the analog sensor used in the connection. It can also act as GPIO (General Purpose Input Output) pins.

Why is Arduino recommended over other boards for beginners?

The USB port in the Arduino board is used to connect the board to the computer using the USB cable. The cable acts as a serial port and as the power supply to interface the board. Such dual functioning makes it unique to recommend and easy to use for beginners.

What is the main difference between Arduino UNO and Arduino Nano?

The Arduino Nano has a compact size and mini USB cable than the Arduino UNO.

What is the main difference between Arduino UNO and Arduino Mega?

The Arduino UNO is a standard board recommended to beginners, while Arduino Mega is used for complex projects due to its greater memory space.


The memory structure is shown in the below image:

Arduino UNO

The preinstalled flash has a bootloader, which takes the memory of 0.5 Kb.

Here, SRAM stands for Static Random Access Memory, and EEPROM stands for Electrically Erasable Programmable Read-Only Memory.

Technical Specifications of Arduino UNO

The technical specifications of the Arduino UNO are listed below:

  • There are 20 Input/Output pins present on the Arduino UNO board. These 20 pis include 6 PWM pins, 6 analog pins, and 8 digital I/O pins.
  • The PWM pins are Pulse Width Modulation capable pins.
  • The crystal oscillator present in Arduino UNO comes with a frequency of 16MHz.
  • It also has a Arduino integrated WiFi module. Such Arduino UNO board is based on the Integrated WiFi ESP8266 Module and ATmega328P microcontroller.
  • The input voltage of the UNO board varies from 7V to 20V.
  • Arduino UNO automatically draws power from the external power supply. It can also draw power from the USB.

How to get started with Arduino UNO?

We can program the Arduino UNO using the Arduino IDE. The Arduino IDE is the Integral Development program, which is common to all the boards.

We can also use Arduino Web Editor, which allows us to upload sketches and write the code from our web browser (Google Chrome recommended) to any Arduino Board. It is an online platform.

The USB connection is essential to connect the computer with the board. After the connection, the PWR pins will light in green. It is a green power LED.

The steps to get started with Arduino UNO are listed below:

  • Install the drivers of the board.

As soon we connect the board to the computer, Windows from XP to 10 will automatically install the board drivers.

But, if you have expanded or downloaded the zip package, follow the below steps:

  1. Click on Start -> Control Panel -> System and Security.
  2. Click on System -> Device Manager -> Ports (COM &LPT) -> Arduino UNO (COMxx). If the COM &LPT is absent, look Other Devices -> Unknown Device.
  3. Right-click to Arduino UNO (COmxx) -> Update Driver Software -> Browse my computer for driver software.
  4. Select the file "inf" to navigate else, select "ArduinoUNO.inf" .
  5. Installation Finished.
  • Open the code or sketch written in the Arduino software.
  • Select the type of board.
    Click on 'Tools' and select Board, as shown below:
    Arduino UNO
  • Select the port. Click on the Tools -> Port (select the port). The port likely will be COM3 or higher. For example, COM6, etc. The COM1 and COM2 ports will not appear, because these two ports are reserved for the hardware serial ports.
  • Now, upload and run the written code or sketch.

To upload and run, click on the button present on the top panel of the Arduino display, as shown below:

Arduino UNO

Within the few seconds after the compile and run of code or sketch, the RX and TX light present on the Arduino board will flash.

The 'Done Uploading' message will appear after the code is successfully uploaded. The message will be visible in the status bar.

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