#define CRC_DR   *(__IO uint8_t*)&(CRC->DR)
  	RCC->AHBENR|=RCC_AHBENR_CRCEN;
      CRC->CR|=CRC_CR_POLSIZE_0|
    	CRC_CR_REV_IN_0|
    	CRC_CR_REV_OUT
                  ;
    	
    *(__IO uint16_t*)&(CRC->INIT)=0xFFFF;
    
    
    
      CRC->CR|=CRC_CR_POLSIZE_0;
    
    
      *(__IO uint16_t*)&(CRC->POL)=0x8005;
      //*(__IO uint16_t*)&(CRC->POL)=0xA001;

    CRC->CR|=CRC_CR_RESET; 

    //11 0F 00 13 00 0A 02 CD 01 BF 0B
	 
	 CRC_DR=0x11;
	 CRC_DR=0x0F;
	 CRC_DR=0x00;
	 CRC_DR=0x13;
	 CRC_DR=0x00;
	 CRC_DR=0x0A;
         CRC_DR=0x02;
	 CRC_DR=0xCD;
	 CRC_DR=0x01;
	 CRC_DR=0xBF;
	 CRC_DR=0x0B;
     
	temp_POL=*(__IO uint16_t*)&(CRC->POL);
	temp_CRC=CRC->DR;

// pay attention
// P_16 -- 0xA001 or 1010 0000 0000 0001 is a reversed form
// of the standard polynom 0x8005 or 1000 0000 0000 0101
#define  P_16        0xA001
 
static unsigned short   crc_tab16[ 256 ];
 
/*******************************************************************\
*                                                                   *
*   static void init_crc16_tab( void );                             *
*                                                                   *
*   The function init_crc16_tab() is used  to  fill  the  array     *
*   for calculation of the CRC-16 with values.                      *
*                                                                   *
\*******************************************************************/
 
void init_crc16_tab( void )
{
 
    unsigned int i, j;
    unsigned short crc, c;
 
    for ( i=0; i < 256; ++i )
    {
 
        crc = 0;
        c = i;
 
        for ( j = 0; j < 8; ++j )
        {
 
            if ( ( crc ^ c ) & 0x0001 )
            {
                crc = ( crc >> 1 ) ^ P_16;
            }
            else
            {
                crc =   crc >> 1;
            }
 
            c = c >> 1;
        }
 
        crc_tab16[ i ] = crc;
    }
   
}  /* init_crc16_tab */
 
 
/*******************************************************************\
*                                                                   *
*   unsigned short update_crc_16( unsigned short crc, char c );     *
*                                                                   *
*   The function update_crc_16 calculates a  new  CRC-16  value     *
*   based  on  the  previous value of the CRC and the next byte     *
*   of the data to be checked.                                      *
*                                                                   *
\*******************************************************************/
 
unsigned short update_crc_16( unsigned short crc, char c )
{
 
    unsigned short tmp, short_c;
 
    short_c = 0x00ff & ( unsigned short ) c;
 
    tmp =  crc         ^ short_c;
    crc = ( crc >> 8 ) ^ crc_tab16[ tmp & 0xff ];
 
    return crc;
 
}  /* update_crc_16 */