Interrupt with C - c

Question

#include <msp430.h>
#define BUTTON BIT3 // Port 1.3
#define REDLED BIT0 // Port 1.0
#define GRNLED BIT6 // Port 1.6
#define ZERO 0x08
#define ONE 0x48
#define TWO 0x09
#define THREE 0x49
int counter = 0;
int main(void) {
// Watchdog setup
WDTCTL = WDTPW + WDTHOLD; // stop watchdog (password + hold counter)
// LED initial setup
P1DIR |= REDLED + GRNLED; // set P1.0 and P1.6 as output (1) pins
P1OUT &= ~REDLED; // Disable REDLED
P1OUT &= ~GRNLED; // Disable GRNLED
// Button setup
P1DIR &= ~BUTTON; // button is an input
P1OUT |= BUTTON; // pull-up resistor
P1REN |= BUTTON; // resistor enabled
P1IE |= 0x08; //P1.3 interrupt enable
P1IES &= ~0x08; //lower edge
P1IFG &= ~0x08; //zero flag
while(1){
}
}
#pragma vector=PORT1_VECTOR
__interrupt void Port_1(void){
counter += 1;
counter = (counter % 4);
switch(counter){
case 0:
P1OUT = ZERO;
break;
case 1:
P1OUT = ONE;
break;
case 2:
P1OUT = TWO;
break;
case 3:
P1OUT = THREE;
break;
}
P1IFG &= ~0x08;
}
I can not enter the ınterrup routine .I checked interrup flag ,when I push the button flag will 1 but the leds are not change ,I think that I can not enter interrup.If I can , the led must be changed.What is the wrong ?

Answer 1

Global interrupts are disabled by default on program's startup. You need to add code that sets the global interrupt enable (GIE) bit at the end of main(). The most platform-independent (not really) way to do it is by calling __enable_interrupts() function.
#include <msp430.h>
#include <intrinsics.h>
...
__enable_interrupts();
Alternatively, set the GIE bit directly:
__bis_status_register(GIE);
To check whether interrupts are enabled (not that inside the interrupt handler they always will be disabled by default):
if (__get_SR_register() & GIE) {
printf("interrupts enabled\n");
} else {
printf("interrupts disabled\n");
}