Arduino Tutorials

Getting Started with Arduino

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In this article, you are going to get an overview of Arduino and its specifications.

Introduction to Arduino

The Arduino Uno is a microcontroller board based on the ATmega328. It has 14 digital input/output pins (of which 6 can be used as PWM outputs), 6 analog inputs, a 16 MHz ceramic resonator, a USB connection, a power jack, an ICSP
header, and a reset button. It contains everything needed to support the microcontroller; simply connect it to a computer with a USB cable or power it with an AC-to-DC adapter or battery to get started.

 Arduino uno pin configuration  

Features of Arduino Uno Board

  • Microcontroller                               ATmega328
  • Operating Voltage                          5V
  • Input Voltage (recommended)       7-12V
  • Input Voltage (limits)                      6-20V
  • Digital I/O Pins                               14 (of which 6 provide PWM output)
  • Analog Input Pins                           6
  • DC Current per I/O Pin                   40 mA
  • DC Current for 3.3V Pin                  50 mA
  • Flash Memory                                 32 KB (ATmega328) of which 0.5 KB used by bootloader
  • SRAM                                              2 KB (ATmega328)
  • EEPROM                                          1 KB (ATmega328)
  • Clock Speed                                    16 MHz

Power

The Arduino Uno can be powered via the USB connection or with an external power supply. The power source is selected automatically.

External (non-USB) power can come either from an AC-to-DC adapter (wall-wart) or battery. The adapter can be connected by plugging a 2.1mm center-positive plug into the board’s power jack. Leads from a battery can be inserted in the Gnd and Vin pin headers of the POWER connector.

The board can operate on an external supply of 6 to 20 volts. If supplied with less than 7V, however, the 5V pin may supply less than five volts and the board may be unstable. If using more than 12V, the voltage regulator may overheat and damage the board. The recommended range is 7 to 12 volts. The power pins are as follows:

  • VIN. The input voltage to the Arduino board when it’s using an external power source (as opposed to 5 volts from the USB connection or other regulated power sources). You can supply voltage through this pin, or, if supplying voltage via the power jack, access it through this pin.
  • 5V.This pin outputs a regulated 5V from the regulator on the board. The board can be supplied with power either from the DC power jack (7 – 12V), the USB connector (5V), or the VIN pin of the board (7-12V).
  • 3V3. A 3.3 volt supply generated by the onboard regulator. The maximum current draw is 50 mA.
  • GND. Ground pins.

Each of the 14 digital pins (pins 0 to 13) on the Uno can be used as an input or output, using pinMode(), digitalWrite(), and digitalRead() functions. They operate at 5 volts. Each pin can provide or receive a maximum of 40 mA and has an internal pull-up resistor (disconnected by default). In addition, some pins have specialized functions as shown below.

Special Functions

  • Serial: 0 (RX) and 1 (TX). Used to receive (RX) and transmit (TX) TTL serial data.
    These pins are connected to the corresponding pins of the ATmega8U2 USB-to-TTL
    Serial chip.
  • External Interrupts: 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.
  • PWM: 3, 5, 6, 9, 10, and 11. Provide 8-bit PWM output with the analogWrite() function.
  • SPI:10(SS), 11(MOSI), 12 (MISO),13 (SCK). These pins support SPI communication using the SPI library.
  • LED: 13. There 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.

The Uno has 6 analog inputs, labeled A0 through A5, each of which provides 10 bits of resolution (i.e. 1024 different values). By default, they measure from ground to 5 volts, though it is possible to change the upper end of their range using the AREF pin and the analogReference() function.

Additionally, some pins have specialized functionality:

  • TWI (I2C): A4 or SDA pin and A5 or SCL pin. Support TWI communication using the Wire library.

Arduino Board Pin Mapping With Atmega 328 Controller

The mapping of an Arduino board with Atmega 328 microcontroller.

atmega328p pin configuration

 

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