Here is my program about a motion security system.This system got one pir sensor,rfid module rdm6300 and a lcd.The problem is 

1;>RFID DATA READING ERROR.The AT89S52 read the data with start bit and stop bit,While i<12……But give correct data when i<14.But compare failed.Means i cant compare the rfid data properly.

2;>LCD giving garbage after running more than 12 hours.What should i do ????

#include<reg52.h>

#include<lcd.h>

#include<string.h>

sbit RELAY = P2^5;

sbit RS = P0^7;

sbit EN = P0^6;

sbit D4 = P0^5;

sbit D5 = P0^4;

sbit D6 = P0^3;

sbit D7 = P0^2;

sbit PIR = P0^0;

sbit SRED = P2^4;

sbit SGREEN = P2^3;

sbit RGREEN = P2^0;

sbit RRED = P2^2;

sbit RBLUE = P2^1;

sbit ALARM=P2^7;

sbit CARD = P3^0;

unsigned char card_id[12] = {"F0200CE7E8D3"} ;

char Data,k;

char j=0,i=0,flag=0;

 

volatile char id[12];                                       

void Delay(int a)

 {

   int j;

   int i;

   for(i=0;i<a;i++)

    {

      for(j=0;j<100;j++)

         {

         }

    }

}

 

 char rcv(void)

  {

 TR1 = 1;

     while(!RI);

 RI = 0;

 TR1 = 0;

    return SBUF;

  }

 

void main()

 {

    P0 = 0;

    P1 = 0;

    P2 = 0;

    P3 = 0;

    RELAY = 0;

    Delay(1000);

    RELAY = 1;

    Delay(500);

    card_id[12]=0;

    id[12]=0;

    Delay(100);

    TMOD = 0x20;

TH1 = 0xFD;

SCON = 0x50;

TR1 =0;

Lcd4_Init();

SBUF = 0;

while(1)

  {

         Lcd4_Clear();

     Lcd4_Set_Cursor(1,0);

     Lcd4_Write_String("Unique ID:");

     id[12]=0;

 Lcd4_Set_Cursor(2,0);

 for(i=0;i<12;i++)

   id = rcv();

 i=0;

 Delay(100);

 Lcd4_Write_String(id);

     Delay(1000);

 if((id[0]=='F')||(id[1]==0)||(id[2]==2)||(id[3]==0)||(id[4]==0)||(id[5]=='C')||(id[6]=='E')||(id[7]==7)||(id[8]=='E')||(id[9]==||(id[10]=='D')||(id[11]=))

 {

   Lcd4_Set_Cursor(1,0);

   Lcd4_Write_String("Access Granted");

   RGREEN = 1;

   SRED = 0;

   Delay(1000);

   Lcd4_Clear();

   RGREEN = 0;

 }

else

 {

   Lcd4_Set_Cursor(1,0);

   Lcd4_Write_String("Acces Denied");

   SRED = 1;

   RGREEN = 0;

   Delay(1000);

   Lcd4_Clear();

   SRED = 0;

}

  }

 }