Program:
#include <pic18f4550.h>
//#include<xc.h>
#define RELAY_PIN LATAbits.LATA4
void __interrupt() extint_isr(void)
{
unsigned int i;
if(INT1IF)
{
INT1IF = 0;
INT1IE = 0;
RELAY_PIN = ~RELAY_PIN;
for(i=0; i<10000; i++); //small delay for debouncing
INT1IE = 1;
}
}
int main(){
ADCON1 = 0x0F; //set pins as Digital in Analog To Digital Control Register 1
TRISAbits.TRISA4 = 0; //set relay pin RA4 as output
TRISBbits.TRISB1 = 1; //Interrupt pin as input
RELAY_PIN = 1;
INT1IE = 1; //Enable external interrupt INT1
INTEDG1 = 0; //Interrupt on falling edge
GIE = 1; // Enable global interrupt
while(1);
}
Output:
