Arduino explanation

 Arduino

The arduino uno is a micro controller board on the ATmega328. It has digital input and output  pins,6 analog input, 16MHZ ceramic resonator, a USB connections, apower jack, and ICSP header,and reset button. 

It was used to hardware and software purpose

If you can easily connect to a computer with a USB cable cable or power it with a AC toDC adapter or battery to get start

Special features of arduino 

It has 1.0 pinout: added SDA and SCL pins that are near to the ARFF pin two other new pins placed near to the RESET PIN, the IOREF that allow the shields to adapt to the voltage provided from the board.

UNO ARDUINO board

Uno means one of the Italian. It named to mark the upcoming release of arduino 1.0.the UNO and version 1.0 will be reference version of arduino. Moving forward.it is latest version of arduino board.

SPECIFICATIONS 

Micro controller                            ATmega328

OPEARATING VOLTAGE                5V

INPUT VOLTAGE                             6- 20V

DIGITAL I/O PINS                             14

ANALIG INPUT PINS                        6

DC CURRENT PER I/O PINS            40MA

DC CURRENT PER 3.3V PIN           50 MA

FLASH MEMORY                              32KB

SRAM                                                    2 KB

PIN DESCRIPTION 

Power

The arduino uno can be powered via the USB connections or with an external power supply.tje power source is selected automatically. 

External power can be come either from an AC to DC adapter. The adapter can be connected by plugging a 2.1mm center positive plug into the board power jack.

VIN

The input voltage to the arduino board when it's using an external power source opposed to 5 volts from the USB connections or other regulated power source.you can supply voltage in this PIN.

5v

Thes PIN output a regulated on the board the board can be supplied with power either from the DC power jack.,the USB connector.

3v3

A 3.3 volts supply generated by the on board regulator .maximum current draw is 50MA.

GND

This is ground PIN

IOREF

this PIN on the arduini board provided the voltage reference with which the microcontroller operates. A properly configuration shield can read the IORREF PIN voltage and select the approximate power source 

I/o pins

each 14 pins on the UNO can be used as an input or output using PIN mode(),digital read()functions.they operate at 5 volts.each pins can provide or receive a maximum of 40 MA and has an internal pull-up resistor of 20-50 pins.

SERIAL PINS 0 AND 1

used to receive and transmitted serial data.this pins are commercial to the corresponding pins of the ATmega8U2 USB-To-TTL 

External interrupts

these PIN can be configured to trigger an interrupts on a low value,a rising or falling edge.

PWS:3, 5, 6, 9, 10, 11.

provide 8-bit PWM output with the analog write() function.

SPI:10(SS), 11(MOSI), 12(MISO), 13(SCK)

these pins support SPI Communication using the SPU library 

LED:13

these 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.

TW1: A4 or SDA pin orA5 or SCL pin support TW1 Communication using the wire library 

AREF

reference voltage for the analog inputs.used with analog reference ()

COMMUNICATION 

The arduino UNO has a number of facilities for Communication with a computer,another arduino, or other microcontroller. The ATmega328 provides UART TTL (5v) serial communications, which is available on digital pin 0 and 1.

PROGRAMMING 

the arduino uno can be programmed with the arduino software ATMEGA328 on the arduino ZNi comes per burned with a boot loader that allows you to upload new code to it without the use of an external  hardware programmer. 

RESET

this is used re start the uploading program for arduino .if you have any error in uploading a program easily the press the reset button.

CONCLUSION 

This are the briefly explanation of the arduino boards , specifications, and pin descriptions.