Baud Rate:
The real meaning of baud rate is bits per second. means how many 0 or 1 passing in one second.

LED Blinking program

If you are working in keil software then copy and past this program:
use AT89S51/52 or AT89C51/52


At PIN 1 (P1.1) add a resistence of 220 Ohm and then connect positive leg of LED with resistance. Connect another end of LED with Ground. LED will starts blink.

Note: Connect PIN 31 and PIN 40 with +5 Volt
PIN 20 with ground
Reset circuit with pin 9

#include <reg51.h>

#include <intrins.h>

void Delay()

{

           unsigned int num;

           for(num=0;num<=5000;num++)

            _nop_();

}

void main()

{

           while(1)

           {

                    P1=    ~P1;

                    Delay();

           }

}