#include <reg51.h>
#include <absacc.h>
void main()
  {
    unsigned char value;
    XDATA[0x4003]=0x90;		
    while(1)
      {
        value = XDATA[0x4000];	
        XDATA[0x4001]=value;	
        XDATA[0x4002]=value;	
      }
  }