#include <reg51.h>
void main(void)
  {
    unsigned char mydata[]={0x25,0x62,0x3F,0x52,0xE8};
    unsigned char chksum=0;
    unsigned char x;
    for(x=0;x<5;x++)
      chksum=chksum+mydata[x];	
    if(chksum==0)
      P0='G';
    else
      P0='B';
  }