/**
  @page CRC_CalculateAndCheck CRC : CRC calculation and computed CRC value checking
  
  @verbatim
  ******************** (C) COPYRIGHT 2016 STMicroelectronics *******************
  * @file    Examples_LL/CRC/CRC_CalculateAndCheck/readme.txt 
  * @author  MCD Application Team
  * @version V1.0.0
  * @date    14-April-2017
  * @brief   Description of the CRC_CalculateAndCheck example.
  ******************************************************************************
  *
  * 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.
  *
  ******************************************************************************
  @endverbatim

@par Example Description

How to configure the CRC calculation unit to compute a CRC code for a given data
buffer, based on a fixed generator polynomial (default value 0x4C11DB7). The
peripheral initialization is done using LL unitary service functions for
optimization purposes (performance and size).

CRC Peripheral is configured to work with default polynomial value (32-bit long).
Normal representation of this polynomial value is :
 X^32 + X^26 + X^23 + X^22 + X^16 + X^12 + X^11 + X^10 +X^8 + X^7 + X^5 + X^4 + X^2 + X + 1.
Generated CRC value is then 32 bits long.

Example execution:
After startup from reset and system configuration, CRC configuration is performed.
CRC code of a given data buffer is computed. 
Data buffer length has been chosen as an exact nb of u32 (32-bit words).
Once calculated, CRC value (uwCRCValue) is compared to the CRC expected value (uwExpectedCRCValue),
and if both are equal, LED2 is turned On. 
In case of errors, LED2 is blinking (1sec period).

@par Directory contents 

  - CRC/CRC_CalculateAndCheck/Inc/stm32f1xx_it.h          Interrupt handlers header file
  - CRC/CRC_CalculateAndCheck/Inc/main.h                  Header for main.c module
  - CRC/CRC_CalculateAndCheck/Inc/stm32_assert.h          Template file to include assert_failed function
  - CRC/CRC_CalculateAndCheck/Src/stm32f1xx_it.c          Interrupt handlers
  - CRC/CRC_CalculateAndCheck/Src/main.c                  Main program
  - CRC/CRC_CalculateAndCheck/Src/system_stm32f1xx.c      STM32F1xx system source file


@par Hardware and Software environment

  - This example runs on STM32F103xB devices.
    
  - This example has been tested with STM32F103RB-Nucleo board and can be
    easily tailored to any other supported device and development board.

@par How to use it ? 

In order to make the program work, you must do the following :
 - Open your preferred toolchain
 - Rebuild all files and load your image into target memory
 - Run the example

 * <h3><center>&copy; COPYRIGHT STMicroelectronics</center></h3>
 */
 