with KEIL4 where the lpc2148 Interrupts or IRQs wont execute - c

Question

When the timer match MR0, run the interrupt service routine At the end of the interrupt service routine. I don't return from service routine to main program. Why does my program not return from service routine?
See answer below for complete code

Answer 1

the code is /* Timer.h */
#include "LPC214x.h"
#include "main.h"
#define VIC_EN 5
#define VIC_TIMER0 4
#define MR0 0
void timer_init(void);
void timer_isr(void);
/* Timer.c */
volatile uint8_t flag;
void timer_init()
{
//disable and reset timer counters
T0TCR = BV(1);
//use T0 as TIMER:
T0CTCR = 0x00;
//set prescalar
T0PR = 15000000-1;
//setup MR0 for 5 sec
T0MR0 = 4; //4+1
//enable intr on MR0, reset
T0MCR |= BV(0) | BV(1);
//enable T0 intr in VIC
VICVectAddr1 = (uint32_t)timer_isr;
VICVectCntl1 = BV(VIC_TIMER0) | VIC_EN;
VICIntSelect &= ~BV(VIC_TIMER0);
VICIntEnable |= BV(VIC_TIMER0);
//enable timer counter
T0TCR = BV(0);
}
void timer_isr()
{
flag=1;
//clear intr in TIMER regrs
T0IR |= BV(0);
//clear intr in VIC
VICVectAddr = 0x00000000;
}
/* Main.c*/
int main (void)
{
int cnt=0;
char str[32];
timer_init();
lcd_init();
lcd_putstring(LCD_LINE1," *TIMER* ");
_delay_ms(1000);
str_printf(str,"Count:%d",cnt);
//lcd_putstring(LCD_LINE2,str);
while(1)
{
while(flag==0);
flag = 0;
cnt++;
str_printf(str,"Count:%d",cnt);
lcd_putstring(LCD_LINE2,str);
}
return 0;
}