Posted on September 09, 2016 at 12:30I could not find a way to use the HAL (created by cubemx) to calculate a CCIT 16 bit CRC.
I did this for the L476 and this workes
/** -------------------------------------------------------------------------
* @brief CRC peripheral initialization CRC_POLYNOMIAL_16B
*/
void initialise_crc16_ccit (void)
{
hcrc.Instance = CRC;
#ifdef STM32L476xx
// The default polynomial is not used. The one to be used must be defined
// in CrcHandle.Init.GeneratingPolynomial
hcrc.Init.DefaultPolynomialUse = DEFAULT_POLYNOMIAL_DISABLE;
// Set the value of the generating polynomial.
// The one used in that example is the 16-bit long CRC generating
// polynomial X^16 + X^12 + X^5 + 1 */
hcrc.Init.GeneratingPolynomial = CRC_POLYNOMIAL_16B;
// The user-defined generating polynomial yields a 16-bit long CRC
hcrc.Init.CRCLength = CRC_POLYLENGTH_16B;
// The default initialise value is not used
hcrc.Init.DefaultInitValueUse = DEFAULT_INIT_VALUE_DISABLE;
// User initialise value is used instead
hcrc.Init.InitValue = CRC_INIT_VALUE;
// The input data are inverted by word
hcrc.Init.InputDataInversionMode = CRC_INPUTDATA_FORMAT_BYTES;
// The bit reversal is done on a full word basis.
// The input stream yielded by CRC16_DATA8[] is the sequence of
// bytes 0x4D, 0x3C, 0x2B, 0x1A, 0xBE, 0x71, ...
// meaning that the first word written in the CRC DR register is
// 0x4D3C2B1A.
// Bit reversal done by the hardware on the full word leads to the actual
// CRC processing of
// 0x58D43CB2.
//
// Similarly, the second word written in the IP is 0xBE71C98A, leading to
// the processing of 0x51938E7D after hardware input data reversal.
//
// Note that when the software writes less than a word in the IP (to minimize the
// number of write accesses for a given number of bytes), the bit-reversal operation
// is carried out only on the input data.
// Therefore, the last written data is the last byte 0x5E, processed as 0x7A
// by the hardware after bit-reversal to wrap-up the CRC computation.
//
// This means that the field InputDataInversionMode set to CRC_INPUTDATA_INVERSION_WORD
// applied to {0x4D, 0x3C, 0x2B, 0x1A, 0xBE, 0x71, 0xC9, 0x8A, 0x5E}
// yields the same result as InputDataInversionMode set to CRC_INPUTDATA_INVERSION_NONE
// applied to {0x58, 0xD4, 0x3C, 0xB2, 0x51, 0x93, 0x8E, 0x7D, 0x7A}.
// The output data are inverted
hcrc.Init.OutputDataInversionMode = CRC_OUTPUTDATA_INVERSION_DISABLED;
// Output data reversal can only be done at bit level.
// The expected CRC is 0x5043 after output data reversal, meaning
// that the CRC before the reversal operation is 0xC20A. */
// The input data are bytes (8-bit long data)
hcrc.InputDataFormat = CRC_INPUTDATA_FORMAT_BYTES;
#endif
#ifdef STM32L151xB
//// @todo Christo we need the CRC for the L151 here
#endif
// De-initialize the CRC peripheral
if (HAL_CRC_DeInit(&hcrc) != HAL_OK)
{
// Initialization Error
Error_Handler();
}
// Then, initialize the CRC handle
if (HAL_CRC_Init(&hcrc) != HAL_OK)
{
// Initialization Error
Error_Handler();
}
}
