Aruino Introuction

The Arduino Uno is a microcontroller board based on the ATmega328,Very popular on open source hardware and software.

  • Operating Voltage-5V.
  • Input Voltage (recommended)7-12V.
  • Input Voltage (limits) 6-20V.
  • DC Current per I/O Pin 40mA.
  • DC Current for 3.3V Pin50 mA.
  • Flash Memory32 KB.
  • SRAM2 KB.
  • Lock Speed 16 MHz.



  • Most of these pins are used to connect to I/O devices.
  • Arduino have 28 pins.
  • It has 14 Digital I/O Pins (of which 6 provide PWM output).
  • It has 6 Analog Input Pins.

Input / Output Pin

  • Serial: 0 (RX) and 1 (TX).Used to receive (RX) and transmit (TX) TTL serial data.
  • The External Interrupts 2 and 3 pin can be configured to trigger an interrupt on a low value, a rising or falling edge, or a change in value.
  • The pins 3, 5, 6, 9, 10, and 11,Provide 8-bit PWM output.
  • SPI: 10 (SS), 11 (MOSI), 12 (MISO), 13 (SCK) these pins support SPI communication.
  • LED: 13.There is a built-in LED connected to digital pin 13.
  • The Uno has 6 analog inputs, labeled A0 through A5, each of which provide 10 bits of resolution (i.e. 1024 different values).
  • TWI: A4 or SDA pin and A5 or SCL pin, Support TWI communication.
  • AREF.Reference voltage for the analog inputs.
  • Reset.Bring this line LOW to reset the microcontroller.
  • Typically used to add a reset button to shields which block the one on the board.