/**
* @brief Initializes the CRC polynomial if different from default one.
* @param hcrc: CRC handle
* @param Pol: CRC generating polynomial (7, 8, 16 or 32-bit long)
* This parameter is written in normal representation, e.g.
* for a polynomial of degree 7, X^7 + X^6 + X^5 + X^2 + 1 is written 0x65
* for a polynomial of degree 16, X^16 + X^12 + X^5 + 1 is written 0x1021
* @param PolyLength: CRC polynomial length
* This parameter can be one of the following values:
* @arg CRC_POLYLENGTH_7B: 7-bit long CRC (generating polynomial of degree 7)
* @arg CRC_POLYLENGTH_8B: 8-bit long CRC (generating polynomial of degree 8)
* @arg CRC_POLYLENGTH_16B: 16-bit long CRC (generating polynomial of degree 16)
* @arg CRC_POLYLENGTH_32B: 32-bit long CRC (generating polynomial of degree 32)
* @retval HAL status
*/
HAL_StatusTypeDef HAL_CRCEx_Polynomial_Set(CRC_HandleTypeDef *hcrc, uint32_t Pol, uint32_t PolyLength)
{
uint32_t msb = 31; /* polynomial degree is 32 at most, so msb is initialized to max value */
/* Check the parameters */
assert_param(IS_CRC_POL_LENGTH(PolyLength));
/* check polynomial definition vs polynomial size:
* polynomial length must be aligned with polynomial
* definition. HAL_ERROR is reported if Pol degree is
* larger than that indicated by PolyLength.
* Look for MSB position: msb will contain the degree of
* the second to the largest polynomial member. E.g., for
* X^7 + X^6 + X^5 + X^2 + 1, msb = 6. */
while (((Pol & ((uint32_t)(0x1) << msb)) == 0) && (msb-- > 0))
{
}
switch (PolyLength)
{
case CRC_POLYLENGTH_7B:
if (msb >= HAL_CRC_LENGTH_7B)
{
return HAL_ERROR;
}
break;
case CRC_POLYLENGTH_8B:
if (msb >= HAL_CRC_LENGTH_8B)
{
return HAL_ERROR;
}
break;
case CRC_POLYLENGTH_16B:
if (msb >= HAL_CRC_LENGTH_16B)
{
return HAL_ERROR;
}
break;
case CRC_POLYLENGTH_32B:
/* no polynomial definition vs. polynomial length issue possible */
break;
default:
break;
}
/* set generating polynomial */
WRITE_REG(hcrc->Instance->POL, Pol);
/* set generating polynomial size */
MODIFY_REG(hcrc->Instance->CR, CRC_CR_POLYSIZE, PolyLength);
/* Return function status */
return HAL_OK;
}
/**
* @brief Initializes the CRC according to the specified
* parameters in the CRC_InitTypeDef and creates the associated handle.
* @param hcrc: CRC handle
* @retval HAL status
*/
HAL_StatusTypeDef HAL_CRC_Init(CRC_HandleTypeDef *hcrc)
{
/* Check the CRC handle allocation */
if(hcrc == NULL)
{
return HAL_ERROR;
}
/* Check the parameters */
assert_param(IS_CRC_ALL_INSTANCE(hcrc->Instance));
if(hcrc->State == HAL_CRC_STATE_RESET)
{
/* Allocate lock resource and initialize it */
hcrc->Lock = HAL_UNLOCKED;
/* Init the low level hardware */
HAL_CRC_MspInit(hcrc);
}
/* Change CRC peripheral state */
hcrc->State = HAL_CRC_STATE_BUSY;
/* check whether or not non-default generating polynomial has been
* picked up by user */
assert_param(IS_DEFAULT_POLYNOMIAL(hcrc->Init.DefaultPolynomialUse));
if (hcrc->Init.DefaultPolynomialUse == DEFAULT_POLYNOMIAL_ENABLE)
{
/* initialize IP with default generating polynomial */
WRITE_REG(hcrc->Instance->POL, DEFAULT_CRC32_POLY);
MODIFY_REG(hcrc->Instance->CR, CRC_CR_POLYSIZE, CRC_POLYLENGTH_32B);
}
else
{
/* initialize CRC IP with generating polynomial defined by user */
assert_param(IS_CRC_POL_LENGTH(hcrc->Init.CRCLength));
if (HAL_CRCEx_Polynomial_Set(hcrc, hcrc->Init.GeneratingPolynomial, hcrc->Init.CRCLength) != HAL_OK)
{
return HAL_ERROR;
}
}
/* check whether or not non-default CRC initial value has been
* picked up by user */
assert_param(IS_DEFAULT_INIT_VALUE(hcrc->Init.DefaultInitValueUse));
if (hcrc->Init.DefaultInitValueUse == DEFAULT_INIT_VALUE_ENABLE)
{
WRITE_REG(hcrc->Instance->INIT, DEFAULT_CRC_INITVALUE);
}
else
{
WRITE_REG(hcrc->Instance->INIT, hcrc->Init.InitValue);
}
/* set input data inversion mode */
assert_param(IS_CRC_INPUTDATA_INVERSION_MODE(hcrc->Init.InputDataInversionMode));
MODIFY_REG(hcrc->Instance->CR, CRC_CR_REV_IN, hcrc->Init.InputDataInversionMode);
/* set output data inversion mode */
assert_param(IS_CRC_OUTPUTDATA_INVERSION_MODE(hcrc->Init.OutputDataInversionMode));
MODIFY_REG(hcrc->Instance->CR, CRC_CR_REV_OUT, hcrc->Init.OutputDataInversionMode);
/* makes sure the input data format (bytes, halfwords or words stream)
* is properly specified by user */
assert_param(IS_CRC_INPUTDATA_FORMAT(hcrc->InputDataFormat));
/* Change CRC peripheral state */
hcrc->State = HAL_CRC_STATE_READY;
/* Return function status */
return HAL_OK;
}