adc reading problem

Hi every one,

I want to control light intensity within a room. I'm using adc0808 interfacing with at89c51. I have attached 3 sensors with adc. None of them give an accurate result. Instead it gives 255 whether light sensors are connected or not. I followed the code mentioned below. Please tell me the problem (if any) in my code or I will check my circuit. Thanks in advance.
<pre>
#include<reg51.h>

void se(unsigned char x);
void con(unsigned char value);
void ms(unsigned int value);

sbit clock=P3^2;
sbit ALE=P3^6;
sbit OE=P3^5;
sbit SC=P3^3;
sbit EOC=P3^4;

sbit Addr_A=P1^0;
sbit Addr_B=P1^1;
sbit Addr_C=P1^2;

sbit Relay1=P1^3;
sbit Relay2=P1^4;
sbit Relay3=P1^5;
sbit Relay4=P1^6;
sbit Relay5=P1^7;


unsigned char lux;
unsigned char array[]={'0','1','2','3','4','5','6','7','8','9'};

void timer0() interrupt 1
{
clock=~clock;
}

void serial0() interrupt 4
{
if(RI==1)
{
RI=0;
lux=SBUF;
se('P');
switch(lux)
{
case ('a'):
Relay1=1;
se('a');
break;

case ('A'):
Relay1=0;
se('A');
break;

case ('b'):
Relay2=1;
se('b');
break;

case ('B'):
Relay2=0;
se('B');
break;

case ('c'):
Relay3=1;
se('c');
break;

case ('C'):
Relay3=0;
se('C');
break;

case ('d'):
Relay4=1;
se('d');
break;

case ('D'):
Relay4=0;
se('D');
break;

case ('e'):
Relay5=1;
se('e');
break;

case ('E'):
Relay5=0;
se('E');
break;

default :
se('N');
}
RI=0;
}
}

void main(void)
{
unsigned char value;

P2=0xFF;
EOC=1;
ALE=0;
OE=0;
SC=0;

TMOD=0x22;
TH1=0xFD;
SCON=0x50;
//IE=0x92;
EA=1;
ES=1;
TR1=1;

TI=0;
RI=0;

// get data from adc
while(1)
{

//use channel 0
ms(30000);
se('x');
Addr_A=0;
Addr_B=0;
Addr_C=0;
ms(255);
ALE=1;
ms(255);
SC=1;
ms(255);
ALE=0;
SC=0;
while(EOC==1);
while(EOC==0);
OE=1;
ms(255);
value=P2;
OE=0;
con(value);
se('X');

//use channel 1

ms(30000);
se('y');
Addr_A=1;
Addr_B=0;
Addr_C=0;
ms(255);
ALE=1;
ms(255);
SC=1;
ms(255);
ALE=0;
SC=0;
while(EOC==1);
while(EOC==0);
OE=1;
ms(255);
value=P2;
OE=0;
con(value);
se('Y');

//use channel 2

ms(30000);
se('z');
Addr_A=0;
Addr_B=1;
Addr_C=0;
ms(255);
ALE=1;
ms(255);
SC=1;
ms(255);
ALE=0;
SC=0;
while(EOC==1);
while(EOC==0);
OE=1;
ms(255);
value=P2;
OE=0;
con(value);
se('Z');
}
}

void ms(unsigned int value)
{
unsigned int x,y;
for(x=0;x<value;x++);
for(y=0;y<1275;y++);
}

void con(unsigned char value)
{
unsigned char x,d1,d2,d3;
x=value/10;
d1=value%10;
d2=x%10;
d3=x/10;
se(array[d3]);
ms(255);
se(array[d2]);
ms(255);
se(array[d1]);
ms(255);
}

void se(unsigned char x)
{
SBUF=x;
while(TI==0);
TI=0;
}
</pre>