Demonstrate the use of an external interrupt to toggle an LED On/Off
Program:-
#include<lpc214x.h>
void Extint0_Isr(void) __irq; //declaration of ISR
unsigned char int_flag = 0, flag = 0;
int main(void)
{
IO1DIR = 0X02000000;
IO1SET = 0X02000000;
PINSEL1 =0X00000001; //Setup P0.16 to alternate function EINT0
EXTMODE =0x01; //edge i.e falling egge trigger and active low
EXTPOLAR= 0X00;
VICVectAddr0 = (unsigned long) Extint0_Isr; //Assign the EINT0 ISR function
VICVectCntl0 = 0x20 | 14; //Assign the VIC channel EINT0 to interrupt priority
0
VICIntEnable = 0x00004000; //Enable the EINT0 interrupt
while(1) //waiting for interrupt to occur
{
if(int_flag == 0x01)
{
if(flag == 0)
{
IO1CLR = 0X02000000;
flag = 1;
}
else if(flag == 1)
{
IO1SET = 0x02000000;
flag = 0;
}
int_flag = 0x00;
}
}
}