i am sorry for las post.
i need to tell that no any problem in hardware.
when i give input by 555 timer at p3.4
it is not displaying that frquency which i give input.
as example
when input frequency is 120khz then out put is 222khz
and when input frequency is 960khz then out out is 1288khz.

sir as i think the problem is that wrong measure of duration of 1 cycle.
so plz

/*******************************************/
/* Frequency Counter With */
/* 89s52 + 4094 */
/*******************************************/
#include <REGX52.H>
#include <math.h>

sbit CLK = P1^1;
sbit DIN = P1^0;
sbit strobe = P1^2;
sbit key = P3^2;

unsigned int calc_del;
unsigned char scale =6;
unsigned char buffer[4],dig[4];
float sample[5];
unsigned long f;
unsigned char segment[10]={0x40,0xF9,0x24,0x30,0x19,0x12,0x02,0xF8,0x00,0x10};
unsigned char a,b,c,d,e;

void delay(y){
unsigned int i;
for(i=0;i<y;i++){;}
}


void int_to_digits(unsigned long number) //store the digits of an integer number in the variable a,b,c,d
{
float itd_a,itd_b,itd_c,itd_d,itd_e;
itd_a = itd_a = number / 10.0;
dig[3] = floor((modf(itd_a,&itd_b)* 10));
itd_b = itd_b / 10.0;
dig[2] = floor((modf(itd_b,&itd_c)* 10));
itd_c = itd_c / 10.0;
dig[1] = floor((modf(itd_c,&itd_d)* 10));
itd_d = itd_d / 10.0;
dig[0] = floor((modf(itd_d,&itd_e)* 10));
}

void count_pulses() interrupt 1 //counter 0 interrupt
{
if (scale < 200)
scale++;
//ex_pulses++;
}


void write_led()

{
char i,j;

for(j=0;j<4;j++)
{
for(i=0;i<8; i++)
{
if(buffer[j]&0x80)
DIN = 1;
else DIN=0;
CLK= 1;
buffer[j] <<=1;
CLK = 0;
}
}
strobe = 1;
;
strobe = 0;
}

void move_Buffer()
{
buffer[3] = segment[dig[0]];
buffer[2] = segment[dig[1]];
buffer[1] = segment[dig[2]];
buffer[0] = segment[dig[3]];
}

void reset() // reset display

{
if( key == 0)
{
f=0;
}
}

void main()
{
EA = 1;
EX0 = 0;
EX1 = 0;
ET0 = 1; //Enable the Timer/counter 0 interrupt
TR0 = 1; //Enable Timer/counter 0 to count
TMOD = 0x25; //counter 0 in mode 1 (16 bit counter) , timer 1 in mode 2 (auto reload from TH1)
TL0 = 0; //empty the counting registers
TH0 = 0; //empty the counting registers
TH1 = 100; //start timer 1 from 0
ET1 = 1; //enable timer 1 interrrupt
TR1 = 1; //Enable Timer/counter 1 to count
PT0 = 1;
PT1 = 0;
while(1)
{
calc_del++;
if (calc_del > (2248/scale)) // update data
{
calc_del = 0;
f = (TL0 +TH0*256);
sample[4] = sample[0] ;
sample[3] = sample[1] ;
sample[2] = sample[2] ;
sample[1] = sample[3] ;
sample[0] = f;
{
TL0=0;
TH0=0;
if (TH0 < 10)
{
if (scale > 9)
{
scale--;
}
}
}

f = floor((sample[0]+sample[1]+sample[2]+sample[3]+sample[4])/5)*scale; // calculate the average of 5 readings
reset();
int_to_digits(f);
move_Buffer();
write_led();
delay(20);
}
}
}


thanks
anil kumar