/*
Arduino function                                                              Arduion function
reset                   (PCINT14/RESET) PC6  1    28 PC5 (ADC5/SCL/PCINT13)       analog input 5
digital pin 0(RX)         (PCINT16/RXD) PD0  2    27 PC4 (ADC4/SDA/PCINT12)       analog input 4
digital pin 1(TX)         (PCINT17/TXD) PD1  3    26 PC3 (ADC3/PCINT11)           analog input 3
digital pin 2            (PCINT18/INT0) PD2  4    25 PC2 (ADC2/PCINT10)           analog input 2
digital pin 3(PWM)  (PCINT19/OC2B/INT1) PD3  5    24 PC1 (ADC1/PCINT9)            analog input 1
digital pin 4          (PCINT20/XCK/T0) PD4  6    23 PC0 (ADC0/PCINT8)            analog input 0
VCC                                     VCC  7    22 GND                                     GND
GND                                     GND  8    21 AREF                       analog reference
crystal            (PCINT6/XTAL1/TOSC1) PB6  9    20 AVCC                                    VCC
crystal            (PCINT7/XTAL2/TOSC2) PB7 10    19 PB5 (SCK/PCINT5)             digital pin 13
digital pin 5(PWM)    (PCINT21/OC0B/T1) PD5 11    18 PB4 (MISO/PCINT4)            digital pin 12
digital pin 6(PWM)  (PCINT22/OC0A/AIN0) PD6 12    17 PB3 (MOSI/OC2A/PCINT3) digital pin 11 (PWM)
digital pin 7            (PCINT23/AIN1) PD7 13    16 PB2 (SS/OC1B/PCINT2)   digital pin 10 (PWM)
digital pin 8        (PCINT0/CLK0/ICP1) PB0 14    15 PB1 (OC1A/PCINT1)      digital pin  9 (PWM)
*/

// Interfacing of Push Buttons with Arduino | Register Level Programming in Arduino T - 15
// https://www.youtube.com/watch?v=FNA0SUYIWCc&list=PL_zvrXFdKgZqiTxipn7WjT_T9hU7ughQH&index=18

void setup() {
  DDRB |= (1 << DDB0);  // PB0 = O/P
  DDRD &= ~(1 << DDD7); // PD7 = I/P
}

void loop() {
  if(PIND & (1 << PIND7))
  {
    PORTB |= (1 << PB0);
  }
  else
  {
    PORTB &= ~(1 << PB0);
  }
}