text: /**
    ******************************************************************************
    * @file    stm32f0xx_hal_crc_ex.c
    * @author  MCD Application Team
    * @version V1.5.0
    * @date    04-November-2016
    * @brief   Extended CRC HAL module driver.
    *          This file provides firmware functions to manage the following 
    *          functionalities of the CRC peripheral:
    *           + Extended initialization functions
    *         
    @verbatim
  ================================================================================
              ##### How to use this driver #####
  ================================================================================
      [..]
           (+) Extended initialization
           (+) Set or not user-defined generating
              polynomial other than default one
  
    @endverbatim
    ******************************************************************************
    * @attention
    *
    * <h2><center>&copy; COPYRIGHT(c) 2016 STMicroelectronics</center></h2>
    *
    * Redistribution and use in source and binary forms, with or without modification,
    * are permitted provided that the following conditions are met:
    *   1. Redistributions of source code must retain the above copyright notice,
    *      this list of conditions and the following disclaimer.
    *   2. Redistributions in binary form must reproduce the above copyright notice,
    *      this list of conditions and the following disclaimer in the documentation
    *      and/or other materials provided with the distribution.
    *   3. Neither the name of STMicroelectronics nor the names of its contributors
    *      may be used to endorse or promote products derived from this software
    *      without specific prior written permission.
    *
    * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
    * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
    * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
    * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
    * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
    * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
    * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
    * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
    * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
    * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
    *
    ******************************************************************************  
    */
  
  /* Includes ------------------------------------------------------------------*/
  #include "stm32f0xx_hal.h"
  
  /** @addtogroup STM32F0xx_HAL_Driver
    * @{
    */
  
  /** @defgroup CRCEx CRCEx 
    * @brief CRC Extended HAL module driver
    * @{
    */
  
  #ifdef HAL_CRC_MODULE_ENABLED
  
  /* Private typedef -----------------------------------------------------------*/
  /* Private define ------------------------------------------------------------*/
  /* Private macro -------------------------------------------------------------*/
  /* Private variables ---------------------------------------------------------*/
  /* Private function prototypes -----------------------------------------------*/
  /* Private functions ---------------------------------------------------------*/
  
  /** @defgroup CRCEx_Exported_Functions CRCEx Exported Functions
    * @{
    */
  
  /** @defgroup CRCEx_Exported_Functions_Group1 Extended Initialization/de-initialization functions
    * @brief    Extended Initialization and Configuration functions.
    *
  @verbatim    
   ===============================================================================
              ##### Initialization and Configuration functions #####
   ===============================================================================
      [..]  This section provides functions allowing to:
        (+) Initialize the CRC generating polynomial: if programmable polynomial 
            feature is applicable to device, set default or non-default generating 
            polynomial according to hcrc->Init.DefaultPolynomialUse parameter.
            If feature is non-applicable to device in use, HAL_CRCEx_Init straight 
            away reports HAL_OK.
        (+) Set the generating polynomial
   
  @endverbatim
    * @{
    */
  
  
  /**
    * @brief  Extended initialization to set generating polynomial
    * @param  hcrc: CRC handle             
    * @retval HAL status
    */             
  HAL_StatusTypeDef HAL_CRCEx_Init(CRC_HandleTypeDef *hcrc)
  {
  #if defined(STM32F071xB) || defined(STM32F072xB) || defined(STM32F078xx) || defined(STM32F091xC) || defined (STM32F098xx)
    /* 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 */
      if (HAL_CRCEx_Polynomial_Set(hcrc, hcrc->Init.GeneratingPolynomial, hcrc->Init.CRCLength) != HAL_OK)
      {
        return HAL_ERROR;
      }
    }
  #endif /* defined(STM32F071xB) || defined(STM32F072xB) || defined(STM32F078xx) || defined(STM32F091xC) || defined (STM32F098xx) */    
  
     return HAL_OK;
  }
  
  /**
    * @brief  Set the Reverse Input data mode.
    * @param  hcrc: CRC handle
    * @param  InputReverseMode: Input Data inversion mode
    *         This parameter can be one of the following values:
    *          @arg CRC_INPUTDATA_NOINVERSION: no change in bit order (default value)
    *          @arg CRC_INPUTDATA_INVERSION_BYTE: Byte-wise bit reversal
    *          @arg CRC_INPUTDATA_INVERSION_HALFWORD: HalfWord-wise bit reversal
    *          @arg CRC_INPUTDATA_INVERSION_WORD: Word-wise bit reversal              
    * @retval HAL status
    */                                   
  HAL_StatusTypeDef HAL_CRCEx_Input_Data_Reverse(CRC_HandleTypeDef *hcrc, uint32_t InputReverseMode)
  {  
    /* Check the parameters */
    assert_param(IS_CRC_INPUTDATA_INVERSION_MODE(InputReverseMode));
    
    /* Change CRC peripheral state */
    hcrc->State = HAL_CRC_STATE_BUSY;
  
    /* set input data inversion mode */
    MODIFY_REG(hcrc->Instance->CR, CRC_CR_REV_IN, InputReverseMode);    
    /* Change CRC peripheral state */
    hcrc->State = HAL_CRC_STATE_READY;
    
    /* Return function status */
    return HAL_OK;
  }
  
  /**
    * @brief  Set the Reverse Output data mode.
    * @param  hcrc: CRC handle
    * @param  OutputReverseMode: Output Data inversion mode
    *         This parameter can be one of the following values:
    *          @arg CRC_OUTPUTDATA_INVERSION_DISABLE: no CRC inversion (default value)
    *          @arg CRC_OUTPUTDATA_INVERSION_ENABLE: bit-level inversion (e.g for a 8-bit CRC: 0xB5 becomes 0xAD)            
    * @retval HAL status
    */                                   
  HAL_StatusTypeDef HAL_CRCEx_Output_Data_Reverse(CRC_HandleTypeDef *hcrc, uint32_t OutputReverseMode)
  {
    /* Check the parameters */
    assert_param(IS_CRC_OUTPUTDATA_INVERSION_MODE(OutputReverseMode));
    
    /* Change CRC peripheral state */
    hcrc->State = HAL_CRC_STATE_BUSY;
  
    /* set output data inversion mode */
    MODIFY_REG(hcrc->Instance->CR, CRC_CR_REV_OUT, OutputReverseMode); 
        
    /* Change CRC peripheral state */
    hcrc->State = HAL_CRC_STATE_READY;
    
    /* Return function status */
    return HAL_OK;
  }
  
  #if defined (STM32F071xB) || defined (STM32F072xB) || defined (STM32F078xx) || defined (STM32F091xC) || defined (STM32F098xx)
  /**
    * @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 = 31U; /* 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 & (1U << msb)) == 0U) && (msb-- > 0U))
    {}
  
    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;
  }
  #endif /* #if defined (STM32F071xB) || defined (STM32F072xB) || defined (STM32F078xx) || defined (STM32F091xC) || defined (STM32F098xx) */
  
  /**
    * @}
    */
  
  
  /**
    * @}
    */
  
  
  #endif /* HAL_CRC_MODULE_ENABLED */
  /**
    * @}
    */
  
  /**
    * @}
    */
  
  /************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/
  