text: /**
    ******************************************************************************
    * @file    stm32h7xx_hal_crc.c
    * @author  MCD Application Team
    * @version V1.1.0
    * @date    31-August-2017
    * @brief   CRC HAL module driver.
    *          This file provides firmware functions to manage the following 
    *          functionalities of the Cyclic Redundancy Check (CRC) peripheral:
    *           + Initialization and de-initialization functions
    *           + Peripheral Control functions 
    *           + Peripheral State functions
    *
    @verbatim
   ===============================================================================
                       ##### CRC How to use this driver #####
   ===============================================================================
      [..]
  
      (#) Enable CRC AHB clock using __HAL_RCC_CRC_CLK_ENABLE();
  
      (#) Initialize CRC calculator
           (++) specify generating polynomial (IP default or non-default one)
           (++) specify initialization value (IP default or non-default one)
           (++) specify input data format
           (++) specify input or output data inversion mode if any
  
      (#) Use HAL_CRC_Accumulate() function to compute the CRC value of the 
          input data buffer starting with the previously computed CRC as 
          initialization value
  
      (#) Use HAL_CRC_Calculate() function to compute the CRC value of the 
          input data buffer starting with the defined initialization value 
          (default or non-default) to initiate CRC calculation
  
    @endverbatim
    ******************************************************************************
    * @attention
    *
    * <h2><center>&copy; COPYRIGHT(c) 2017 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 "stm32h7xx_hal.h"
  
  /** @addtogroup STM32H7xx_HAL_Driver
    * @{
    */
  
  /** @defgroup CRC CRC
    * @brief CRC HAL module driver.
    * @{
    */
  
  #ifdef HAL_CRC_MODULE_ENABLED
  
  /* Private typedef -----------------------------------------------------------*/
  /* Private define ------------------------------------------------------------*/
  /* Private macro -------------------------------------------------------------*/
  /* Private variables ---------------------------------------------------------*/
  /* Private function prototypes -----------------------------------------------*/
  static uint32_t CRC_Handle_8(CRC_HandleTypeDef *hcrc, uint8_t pBuffer[], uint32_t BufferLength);
  static uint32_t CRC_Handle_16(CRC_HandleTypeDef *hcrc, uint16_t pBuffer[], uint32_t BufferLength);
  /* Exported functions --------------------------------------------------------*/
  
  /** @defgroup CRC_Exported_Functions CRC Exported Functions
    * @{
    */
  
  /** @defgroup HAL_CRC_Group1 Initialization/de-initialization functions 
    *  @brief    Initialization and Configuration functions. 
    *
  @verbatim    
   ===============================================================================
              ##### Initialization and de-initialization functions #####
   ===============================================================================
      [..]  This section provides functions allowing to:
        (+) Initialize the CRC according to the specified parameters 
            in the CRC_InitTypeDef and create the associated handle
        (+) DeInitialize the CRC peripheral
        (+) Initialize the CRC MSP
        (+) DeInitialize CRC MSP 
   
  @endverbatim
    * @{
    */
  
  /**
    * @brief  Initialize the CRC according to the specified
    *         parameters in the CRC_InitTypeDef and create 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 */
      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;
  }
  
  /**
    * @brief  DeInitialize the CRC peripheral.
    * @param  hcrc: CRC handle
    * @retval HAL status
    */
  HAL_StatusTypeDef HAL_CRC_DeInit(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));
    
    /* Check the CRC peripheral state */
    if(hcrc->State == HAL_CRC_STATE_BUSY)
    {
      return HAL_BUSY;
    }
    
    /* Change CRC peripheral state */
    hcrc->State = HAL_CRC_STATE_BUSY;
    
    /* Reset CRC calculation unit */
    __HAL_CRC_DR_RESET(hcrc);
    
    /* Reset IDR register content */
    CLEAR_BIT(hcrc->Instance->IDR, CRC_IDR_IDR);
  
    /* DeInit the low level hardware */
    HAL_CRC_MspDeInit(hcrc);
  
    /* Change CRC peripheral state */
    hcrc->State = HAL_CRC_STATE_RESET;
  
    /* Process unlocked */
    __HAL_UNLOCK(hcrc);
  
    /* Return function status */
    return HAL_OK;
  }
  
  /**
    * @brief  Initialize the CRC MSP.
    * @param  hcrc: CRC handle
    * @retval None
    */
  __weak void HAL_CRC_MspInit(CRC_HandleTypeDef *hcrc)
  {
    /* Prevent unused argument(s) compilation warning */
    UNUSED(hcrc);
    
    /* NOTE : This function should not be modified, when the callback is needed,
              the HAL_CRC_MspInit can be implemented in the user file
     */
  }
  
  /**
    * @brief  DeInitialize the CRC MSP.
    * @param  hcrc: CRC handle
    * @retval None
    */
  __weak void HAL_CRC_MspDeInit(CRC_HandleTypeDef *hcrc)
  {
    /* Prevent unused argument(s) compilation warning */
    UNUSED(hcrc);
    
    /* NOTE : This function should not be modified, when the callback is needed,
              the HAL_CRC_MspDeInit can be implemented in the user file
     */
  }
  
  /**
    * @}
    */
  
  /** @defgroup HAL_CRC_Group2 Peripheral Control functions 
    *  @brief   Peripheral Control functions 
    *
  @verbatim  
   ==============================================================================
                        ##### Peripheral Control functions #####
   ==============================================================================  
      [..]  This section provides functions allowing to:
        (+) Compute the 7, 8, 16 or 32-bit CRC value of an 8, 16 or 32-bit data buffer
            using combination of the previous CRC value and the new one.
            
            or
            
        (+) Compute the 7, 8, 16 or 32-bit CRC value of an 8, 16 or 32-bit data buffer
            independently of the previous CRC value.
  
  @endverbatim
    * @{
    */
  
  /**                  
    * @brief  Compute the 7, 8, 16 or 32-bit CRC value of an 8, 16 or 32-bit data buffer
    *         starting with the previously computed CRC as initialization value.
    * @param  hcrc: CRC handle
    * @param  pBuffer: pointer to the input data buffer, exact input data format is
    *         provided by hcrc->InputDataFormat.  
    * @param  BufferLength: input data buffer length (number of bytes if pBuffer
    *         type is * uint8_t, number of half-words if pBuffer type is * uint16_t,
    *         number of words if pBuffer type is * uint32_t).
    * @note  By default, the API expects a uint32_t pointer as input buffer parameter.
    *        Input buffer pointers with other types simply need to be cast in uint32_t
    *        and the API will internally adjust its input data processing based on the  
    *        handle field hcrc->InputDataFormat.  
    * @retval uint32_t CRC (returned value LSBs for CRC shorter than 32 bits)
    */
  uint32_t HAL_CRC_Accumulate(CRC_HandleTypeDef *hcrc, uint32_t pBuffer[], uint32_t BufferLength)
  {
    uint32_t index = 0; /* CRC input data buffer index */
    uint32_t temp = 0;  /* CRC output (read from hcrc->Instance->DR register) */
    
    /* Process locked */
    __HAL_LOCK(hcrc); 
      
    /* Change CRC peripheral state */  
    hcrc->State = HAL_CRC_STATE_BUSY;
    
    switch (hcrc->InputDataFormat)
    {
      case CRC_INPUTDATA_FORMAT_WORDS:  
        /* Enter Data to the CRC calculator */
        for(index = 0; index < BufferLength; index++)
        {
          hcrc->Instance->DR = pBuffer[index];
        }
        temp = hcrc->Instance->DR;
        break;
        
      case CRC_INPUTDATA_FORMAT_BYTES: 
        temp = CRC_Handle_8(hcrc, (uint8_t*)pBuffer, BufferLength);
        break;
        
      case CRC_INPUTDATA_FORMAT_HALFWORDS: 
        temp = CRC_Handle_16(hcrc, (uint16_t*)pBuffer, BufferLength);
        break;
      default:
        break;  
    }
    
    /* Change CRC peripheral state */    
    hcrc->State = HAL_CRC_STATE_READY; 
    
    /* Process unlocked */
    __HAL_UNLOCK(hcrc);
    
    /* Return the CRC computed value */ 
    return temp;
  }
  
  /**                  
    * @brief  Compute the 7, 8, 16 or 32-bit CRC value of an 8, 16 or 32-bit data buffer
    *         starting with hcrc->Instance->INIT as initialization value.
    * @param  hcrc: CRC handle
    * @param  pBuffer: pointer to the input data buffer, exact input data format is
    *         provided by hcrc->InputDataFormat.  
    * @param  BufferLength: input data buffer length (number of bytes if pBuffer
    *         type is * uint8_t, number of half-words if pBuffer type is * uint16_t,
    *         number of words if pBuffer type is * uint32_t).
    * @note  By default, the API expects a uint32_t pointer as input buffer parameter.
    *        Input buffer pointers with other types simply need to be cast in uint32_t
    *        and the API will internally adjust its input data processing based on the  
    *        handle field hcrc->InputDataFormat.   
    * @retval uint32_t CRC (returned value LSBs for CRC shorter than 32 bits)
    */  
  uint32_t HAL_CRC_Calculate(CRC_HandleTypeDef *hcrc, uint32_t pBuffer[], uint32_t BufferLength)
  {
    uint32_t index = 0; /* CRC input data buffer index */
    uint32_t temp = 0;  /* CRC output (read from hcrc->Instance->DR register) */
      
    /* Process locked */
    __HAL_LOCK(hcrc); 
    
    /* Change CRC peripheral state */  
    hcrc->State = HAL_CRC_STATE_BUSY;
    
    /* Reset CRC Calculation Unit (hcrc->Instance->INIT is 
    *  written in hcrc->Instance->DR) */
    __HAL_CRC_DR_RESET(hcrc);
    
    switch (hcrc->InputDataFormat)
    {
      case CRC_INPUTDATA_FORMAT_WORDS:  
        /* Enter 32-bit input data to the CRC calculator */
        for(index = 0; index < BufferLength; index++)
        {
          hcrc->Instance->DR = pBuffer[index];
        }
        temp = hcrc->Instance->DR;
        break;
        
      case CRC_INPUTDATA_FORMAT_BYTES: 
        /* Specific 8-bit input data handling  */
        temp = CRC_Handle_8(hcrc, (uint8_t*)pBuffer, BufferLength);
        break;
        
      case CRC_INPUTDATA_FORMAT_HALFWORDS: 
        /* Specific 16-bit input data handling  */
        temp = CRC_Handle_16(hcrc, (uint16_t*)pBuffer, BufferLength);
        break;
      default:
        break;
    }
  
    /* Change CRC peripheral state */
    hcrc->State = HAL_CRC_STATE_READY;
  
    /* Process unlocked */
    __HAL_UNLOCK(hcrc);
    
    /* Return the CRC computed value */ 
    return temp;
  }
  
  /**             
    * @brief  Enter 8-bit input data to the CRC calculator.
    *         Specific data handling to optimize processing time.  
    * @param  hcrc: CRC handle
    * @param  pBuffer: pointer to the input data buffer
    * @param  BufferLength: input data buffer length
    * @retval uint32_t CRC (returned value LSBs for CRC shorter than 32 bits)
    */
  static uint32_t CRC_Handle_8(CRC_HandleTypeDef *hcrc, uint8_t pBuffer[], uint32_t BufferLength)
  {
    uint32_t i = 0; /* input data buffer index */
    
     /* Processing time optimization: 4 bytes are entered in a row with a single word write,
      * last bytes must be carefully fed to the CRC calculator to ensure a correct type
      * handling by the IP */
     for(i = 0; i < (BufferLength/4); i++)
     {
       hcrc->Instance->DR = (uint32_t)(((uint32_t)(pBuffer[4*i])<<24) | ((uint32_t)(pBuffer[4*i+1])<<16) | ((uint32_t)(pBuffer[4*i+2])<<8) | (uint32_t)(pBuffer[4*i+3]));
     }
     /* last bytes specific handling */
     if((BufferLength%4) != 0)
     {
       if(BufferLength%4 == 1)
       {
         *(__IO uint8_t*) (&hcrc->Instance->DR) = pBuffer[4*i];
       }
       if(BufferLength%4 == 2)
       {
         *(__IO uint16_t*) (&hcrc->Instance->DR) = (uint16_t)((uint16_t)((uint16_t)(pBuffer[4*i])<<8) | (uint16_t)(pBuffer[4*i+1]));       
       }
       if(BufferLength%4 == 3)
       {
         *(__IO uint16_t*) (&hcrc->Instance->DR) = (uint16_t)((uint16_t)((uint16_t)(pBuffer[4*i])<<8) | (uint16_t)(pBuffer[4*i+1]));
         *(__IO uint8_t*) (&hcrc->Instance->DR) = pBuffer[4*i+2];       
       }
     }
    
    /* Return the CRC computed value */ 
    return hcrc->Instance->DR;
  }
  
  /**             
    * @brief  Enter 16-bit input data to the CRC calculator.
    *         Specific data handling to optimize processing time.  
    * @param  hcrc: CRC handle
    * @param  pBuffer: pointer to the input data buffer
    * @param  BufferLength: input data buffer length
    * @retval uint32_t CRC (returned value LSBs for CRC shorter than 32 bits)
    */  
  static uint32_t CRC_Handle_16(CRC_HandleTypeDef *hcrc, uint16_t pBuffer[], uint32_t BufferLength)
  {
    uint32_t i = 0;  /* input data buffer index */
    
    /* Processing time optimization: 2 HalfWords are entered in a row with a single word write,
     * in case of odd length, last HalfWord must be carefully fed to the CRC calculator to ensure 
     * a correct type handling by the IP */
    for(i = 0; i < (BufferLength/2); i++)
    {
      hcrc->Instance->DR = (((uint32_t)(pBuffer[2*i])<<16) | (uint32_t)(pBuffer[2*i+1]));
    }
    if((BufferLength%2) != 0)
    {
       *(__IO uint16_t*) (&hcrc->Instance->DR) = pBuffer[2*i]; 
    }
     
    /* Return the CRC computed value */ 
    return hcrc->Instance->DR;
  }
  
  /**
    * @}
    */
  
  /** @defgroup HAL_CRC_Group3 Peripheral State functions 
    *  @brief    Peripheral State functions. 
    *
  @verbatim   
   ==============================================================================
                        ##### Peripheral State functions #####
   ==============================================================================  
      [..]
      This subsection permits to get in run-time the status of the peripheral 
      and the data flow.
  
  @endverbatim
    * @{
    */
  
  /**
    * @brief  Return the CRC state.
    * @param  hcrc: CRC handle
    * @retval HAL state
    */
  HAL_CRC_StateTypeDef HAL_CRC_GetState(CRC_HandleTypeDef *hcrc)
  {
    return hcrc->State;
  }
  
  /**
    * @}
    */
  
  /**
    * @}
    */
  
  #endif /* HAL_CRC_MODULE_ENABLED */
  /**
    * @}
    */
  
  /**
    * @}
    */
  
  /************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/
  