/* 
 Filename: intEx1 
 Author: Jhaved Jesus II Bucaling
 Date: 4/18/24
 Description: 
Code to test external interrupts: every time PCINT0 is triggered, 
 the red shield LED7 is toggled 
*/ 
#include <avr/io.h> 
#include <avr/interrupt.h> 
#include <avr/pgmspace.h> 
#include <util/delay.h> 
//user-defined function for the initialisation of the external interrupt PCINT0 
void pcint0_init(void); 
void pcint1_init(void); 
void pcint2_init(void); 
void pcint3_init(void); 
volatile unsigned char PinChange0 = 0; //global variable, initialised to False 
volatile unsigned char PinChange1 = 0; //global variable, initialised to False 
volatile unsigned char PinChange2 = 0;//global variable, initialised to False 

volatile unsigned char counter = 0; // Global variable for debugging code 
int main(void) 
{//--- User initializations. 
 DDRB = 0xF0; // NOTE: configure only PB0 (PCINT0) as input
 PORTB = 0x0F; // activate only its pull up resistor, and turn off LED
 DDRH = 0xF0; // NOTE: configure only PB0 (PCINT8) as input
 PORTH = 0x0F;// activate only its pull up resistor, and turn off LED
 DDRK = 0xF0; // NOTE: configure only PB0 (PCINT16) as input
 PORTK = 0x0F;// activate only its pull up resistor, and turn off LED
 DDRA = 0xFF; // All Port A configured as output 
 pcint0_init(); // initialise registers to enable PCINT0 
  pcint1_init();// initialise registers to enable PCINT8 
  pcint2_init();// initialise registers to enable PCINT16 
  

 while(1) 
 { 
 if(PinChange0) // Check if pin change detected 
 { 
 PORTA |= 0x80; 
 _delay_ms(1000); 
 PORTA &= ~0x80; 
 PinChange0 = 0; // Reset pin change detection 
 } 

 if(PinChange1) // Check if pin change detected 
 { 
 PORTA |= 0x40; 
 _delay_ms(1000); 
 PORTA &= ~0x40; 
 PinChange1 = 0; // Reset pin change detection 
 } 

 if(PinChange2) // Check if pin change detected 
 { 
 PORTA |= 0x20; 
 _delay_ms(1000); 
 PORTA &= ~0x20; 
 PinChange2 = 0; // Reset pin change detection 
 } 

 } 
} 
//user-defined function for the initialisation of the external interrupt PCINT0 
void pcint0_init(void) 
{ 
 cli(); // SREG = 0 
 PCICR |= (1 << PCIE0); 
 PCMSK0 |= (1 << PCINT0)|(1 << PCINT1); // Port B, Pin53
 PCIFR |= (1 << PCIF0); 
 sei(); // SREG = 1 
} 
void pcint1_init(void) 
{ 
 cli(); // SREG = 0 
 PCICR |= (1 << PCIE1); 
 PCMSK1 |= (1 << PCINT8); // Port H, pin 0
 PCIFR |= (1 << PCIF1); 
 sei(); // SREG = 1 
} 
void pcint2_init(void) 
{ 
 cli(); // SREG = 0 
 PCICR |= (1 << PCIE2); 
 PCMSK2 |= (1 << PCINT16)|(1 << PCINT17); // Port K, pin 8
 PCIFR |= (1 << PCIF2); 
 sei(); // SREG = 1 
} 

//interrupt-service routine 
ISR(PCINT0_vect) 
{ 
 PinChange0 = 1; 
 PCIFR = PCIFR | (1 << PCIF0);// re-arm the interrupt – IMPORTANT!!!
 } 

ISR(PCINT1_vect) 
{ 
 PinChange1 = 1; 
 PCIFR = PCIFR | (1 << PCIF1);// re-arm the interrupt – IMPORTANT!!!
 } 

ISR(PCINT2_vect) 
{ 
 PinChange2 = 1; 
 PCIFR = PCIFR | (1 << PCIF2);// re-arm the interrupt – IMPORTANT!!!
 }