8051_timerAutoReload.c

#include<reg51.h>
sbit LED = P0^0;

void timer0_isr() interrupt 1
{
    LED =! LED;       // Toggle the LED pin,
                      //Note Timer value is not reloaded, It is automatically taken care 
}

void main()
{
    TMOD = 0x02;       //Timer0 mode 2
    TH0 = 0X1A;        //Load the timer value
    TR0 = 1;           //turn ON Timer zero
    ET0 = 1;           //Enable TImer0 Interrupt
    EA = 1;            //Enable Global Interrupt bit
    while(1)
    {
        // Do nothing
    } 
}