Arduino UNO

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Arduino Uno has 14 digital I/O pins (0-13) and 6 analog pins (A0-A5).

This sketch initializes all the pins and includes a basic setup for reference, with comments on how you might handle different types of pins.

#include <Wire.h> //for I2C communication
#include <SPI.h> //for SPI communication
#include <Servo.h> //for controlling servos
#include <LiquidCrystal.h> //for controlling LCD displays
#include <EEPROM.h> //for working with EEPROM storage
#include <SD.h> //for interfacing with an SD card

Pin Definitions

// Pin definitions
const int digitalPins[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13};  // Digital I/O pins (0-13)
const int analogPins[] = {A0, A1, A2, A3, A4, A5};  // Analog pins (A0-A5)

Debugging

void setup() {
  // Start serial communication for debugging
  Serial.begin(9600);
  Serial.println("Print debug message");
}

Set the pin mode

  • to be input or output 
    void setup() {
  pinMode(digitalPins[i], OUTPUT);  // Set digital pins as OUTPUT
  digitalWrite(digitalPins[i], LOW); // Set them to LOW for safety
    
  pinMode(analogPins[i], INPUT);  // Set analog pins as INPUT
    
  // Configure pin 9 for PWM (Pulse Width Modulation)
  pinMode(9, OUTPUT);  // Pin 9 supports PWM
  Serial.println("Pin 9 initialized for PWM (Output)");
    
  // Configure pin 2 as an interrupt
pinMode(2, INPUT_PULLUP);  // Enable internal pull-up resistor for interrupt-based usage
Serial.println("Pin 2 initialized as INPUT_PULLUP for interrupt");
}

    Digital Pins (0-13):

  • Pin 13: The Arduino Uno has a built-in LED connected to pin 13 often used for basic testing.
  • Pins 2-13: These are general-purpose I/O pins that can be set as either INPUT or OUTPUT.
  • Pin 9 supports PWM (Pulse Width Modulation), so it can be used for dimming LEDs or controlling motors.

Analog Pins (A0-A5):

  • Analog pins (A0 to A5) are used for reading analog signals.
  • By default, they are in INPUT mode.
  • Read values from them using analogRead() and
  • write analog outputs using analogWrite() on PWM-capable pins.

PWM Pins:

The Arduino Uno has PWM capabilities on pins 3, 5, 6, 9, 10, and 11. These pins can be used to create a simulated analog output signal using analogWrite().

Interrupts:

Pin 2 and Pin 3 on the Arduino Uno are capable of handling interrupts. You can use attachInterrupt() to trigger actions when a signal changes on these pins.

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