/**
*     Copyright (c) 2022, Nations Technologies Inc.
* 
*     All rights reserved.
*
*     This software is the exclusive property of Nations Technologies Inc. (Hereinafter 
* referred to as NATIONS). This software, and the product of NATIONS described herein 
* (Hereinafter referred to as the Product) are owned by NATIONS under the laws and treaties
* of the People's Republic of China and other applicable jurisdictions worldwide.
*
*     NATIONS does not grant any license under its patents, copyrights, trademarks, or other 
* intellectual property rights. Names and brands of third party may be mentioned or referred 
* thereto (if any) for identification purposes only.
*
*     NATIONS reserves the right to make changes, corrections, enhancements, modifications, and 
* improvements to this software at any time without notice. Please contact NATIONS and obtain 
* the latest version of this software before placing orders.

*     Although NATIONS has attempted to provide accurate and reliable information, NATIONS assumes 
* no responsibility for the accuracy and reliability of this software.
* 
*     It is the responsibility of the user of this software to properly design, program, and test 
* the functionality and safety of any application made of this information and any resulting product. 
* In no event shall NATIONS be liable for any direct, indirect, incidental, special,exemplary, or 
* consequential damages arising in any way out of the use of this software or the Product.
*
*     NATIONS Products are neither intended nor warranted for usage in systems or equipment, any
* malfunction or failure of which may cause loss of human life, bodily injury or severe property 
* damage. Such applications are deemed, "Insecure Usage".
*
*     All Insecure Usage shall be made at user's risk. User shall indemnify NATIONS and hold NATIONS 
* harmless from and against all claims, costs, damages, and other liabilities, arising from or related 
* to any customer's Insecure Usage.

*     Any express or implied warranty with regard to this software or the Product, including,but not 
* limited to, the warranties of merchantability, fitness for a particular purpose and non-infringement
* are disclaimed to the fullest extent permitted by law.

*     Unless otherwise explicitly permitted by NATIONS, anyone may not duplicate, modify, transcribe
* or otherwise distribute this software for any purposes, in whole or in part.
*
*     NATIONS products and technologies shall not be used for or incorporated into any products or systems
* whose manufacture, use, or sale is prohibited under any applicable domestic or foreign laws or regulations. 
* User shall comply with any applicable export control laws and regulations promulgated and administered by 
* the governments of any countries asserting jurisdiction over the parties or transactions.
**/

/**
*\*\file main.c
*\*\author Nations
*\*\version v1.0.0
*\*\copyright Copyright (c) 2022, Nations Technologies Inc. All rights reserved.
**/
#include "n32a003.h"
#include "main.h"

#define CRC_DFE_POLY 0x8005

static const uint8_t Buffer[8] = {0x7e, 0x11, 0x36, 0x4e, 0x55, 0x0a, 0xf1, 0x1a};

__IO uint32_t CRCValue   = 0;
__IO uint16_t CRC16Value = 0;

/**
*\*\name    ReverseBits.
*\*\fun     Bitwise reversal.
*\*\param   bufin
*\*\return  bufout
**/
uint8_t ReverseBits(uint8_t bufin)
{
    uint8_t bufout = 0;
    uint8_t j      = 0;
    for (j = 0; j < 4; j++)
    {
        bufout |= (bufin & (0x01 << j)) << (7 - 2 * j);
        bufout |= (bufin & (0x10 << (j))) >> (2 * j + 1);
    }
    return bufout;
}

/**
*\*\name    GetCRC16_Software.
*\*\fun     Software calculates CRC16.
*\*\param   buf
*\*\param   len
*\*\param   initcrc
*\*\return  crc16
**/
uint16_t GetCRC16_Software(uint8_t* buf, uint32_t len, uint16_t initcrc)
{
    uint16_t crc16 = initcrc;
    uint8_t i = 0, j = 0;

    for (i = 0; i < len; i++)
    {
        crc16 ^= (uint16_t)(buf[i] << 8);
        for (j = 0; j < 8; j++)
        {
            if ((crc16 & 0x8000) > 0)
            {
                crc16 = (uint16_t)((crc16 << 1) ^ CRC_DFE_POLY);
            }
            else
            {
                crc16 <<= 1;
            }
        }
    }
    return crc16;
}

/**
*\*\name    main.
*\*\fun     Main program.
*\*\param   none
*\*\return  none
**/
int main(void)
{    
    /* Enable CRC clock */
    RCC_AHB_Peripheral_Clock_Enable(RCC_AHB_PERIPH_CRC);

    /* Compute the 16bit CRC of an array */
    CRC16Value = CRC16_Buffer_Calculate((uint8_t*)Buffer, 8);
    
    /* Compute the 16bit CRC of an array by software*/
    CRCValue   = GetCRC16_Software((uint8_t*)Buffer, 8, 0x00);

    while (1)
    {
    }
}

