Following is the video tutorial on Arduino, which explains the Hardware and Software point of view,
Covers Following points,
1. Schematic of Arduino board is Explained
2. Bootloader Concept
3. How to use Web Editor
4. How to Use Arduino IDE
5. Example on LED Blink
6. Example on Serial Interface
7. Example on Switch interface using polling method
8. Example on Switch interface using interrupt method
9. Example on ADC

Here is the link,

Hope you like it,
[Note : Please move the post if it not in correct Section]

 

Here is code for interrupt based key interface

#define KEY_IN  2

void keypress(void)
{
  Serial.println("Key Pressed !!!");
}


// the setup function runs once when you press reset or power the board
void setup() {
  // initialize digital pin LED_BUILTIN as an output.
  pinMode(LED_BUILTIN, OUTPUT);
  pinMode(KEY_IN,INPUT_PULLUP);
  Serial.begin(9600);
  attachInterrupt(digitalPinToInterrupt(2),keypress,LOW);
}



// the loop function runs over and over again forever
void loop() {
  digitalWrite(LED_BUILTIN,HIGH);
  delay(1000);
  digitalWrite(LED_BUILTIN,LOW);
  delay(1000);
}

 

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