#pragma interrupt_handler timer0_ovf_isr:10  //TIMER0 定時2ms中斷.
void timer0_ovf_isr(void)
{
 TCNT0 = 0xD9; //reload counter value
 timer2ms++;
    if(timer2ms >= 5)
    {
     timer2ms = 0;
     timer10ms ++;
     systimer10ms ++;
      if(systimer10ms >= 22)  //內部1M晶振
       {
       systimer10ms = 0;
       timer1s ++;
}
}
網上找到的