Hello,
I wrote a small code to check it

#include<reg51.h>

sbit pin = 0xb0; //p3.0
void main()
{
char count=20 ;
pin = 0; //Clr P3.0
while(count)
{
TMOD = 0x01;
TH0 = 0x3c;
TL0 = 0xaf;
TR0 = 1;
while(!TF0);
TF0 = 0;
count--;
}
pin = 1; //Set P3.0
while(1);
}

I checked on DSO, it takes 4 seconds to enter main().
Again the same code is on AT89c2051.

Keil Compiler version is 6.23a

I dont understand the reason for 4 seconds delay.

Pravin