sd_crc.c

Atmega64单片机程序（完整工程）

/*--------------File Info-------------------------------------------------------
** 文   件   名:    SD_CRC.c
** 最后修改日期:    2008.3.28
** 版        本:    V1.0
** 描        述:    CRC校验		
**------------------------------------------------------------------------------
** Created   by:    		
** Created date:			
*******************************************************************************/

#include "SYS_Config.h" 
#include "SD_Config.h" 
#include "SD_Hal.h" 
#include "SD_Drive.h" 


#if SD_CRC_EN 

INT16U const CRCTable[256]=     //X16 + X12 + X5 + 1 余式表
{
    0x0000,0x1021,0x2042,0x3063,0x4084,0x50a5,0x60c6,0x70e7,
    0x8108,0x9129,0xa14a,0xb16b,0xc18c,0xd1ad,0xe1ce,0xf1ef,
    0x1231,0x0210,0x3273,0x2252,0x52b5,0x4294,0x72f7,0x62d6,
    0x9339,0x8318,0xb37b,0xa35a,0xd3bd,0xc39c,0xf3ff,0xe3de,
    0x2462,0x3443,0x0420,0x1401,0x64e6,0x74c7,0x44a4,0x5485,
    0xa56a,0xb54b,0x8528,0x9509,0xe5ee,0xf5cf,0xc5ac,0xd58d,
    0x3653,0x2672,0x1611,0x0630,0x76d7,0x66f6,0x5695,0x46b4,
    0xb75b,0xa77a,0x9719,0x8738,0xf7df,0xe7fe,0xd79d,0xc7bc,
    0x48c4,0x58e5,0x6886,0x78a7,0x0840,0x1861,0x2802,0x3823,
    0xc9cc,0xd9ed,0xe98e,0xf9af,0x8948,0x9969,0xa90a,0xb92b,
    0x5af5,0x4ad4,0x7ab7,0x6a96,0x1a71,0x0a50,0x3a33,0x2a12,
    0xdbfd,0xcbdc,0xfbbf,0xeb9e,0x9b79,0x8b58,0xbb3b,0xab1a,
    0x6ca6,0x7c87,0x4ce4,0x5cc5,0x2c22,0x3c03,0x0c60,0x1c41,
    0xedae,0xfd8f,0xcdec,0xddcd,0xad2a,0xbd0b,0x8d68,0x9d49,
    0x7e97,0x6eb6,0x5ed5,0x4ef4,0x3e13,0x2e32,0x1e51,0x0e70,
    0xff9f,0xefbe,0xdfdd,0xcffc,0xbf1b,0xaf3a,0x9f59,0x8f78,
    0x9188,0x81a9,0xb1ca,0xa1eb,0xd10c,0xc12d,0xf14e,0xe16f,
    0x1080,0x00a1,0x30c2,0x20e3,0x5004,0x4025,0x7046,0x6067,
    0x83b9,0x9398,0xa3fb,0xb3da,0xc33d,0xd31c,0xe37f,0xf35e,
    0x02b1,0x1290,0x22f3,0x32d2,0x4235,0x5214,0x6277,0x7256,
    0xb5ea,0xa5cb,0x95a8,0x8589,0xf56e,0xe54f,0xd52c,0xc50d,
    0x34e2,0x24c3,0x14a0,0x0481,0x7466,0x6447,0x5424,0x4405,
    0xa7db,0xb7fa,0x8799,0x97b8,0xe75f,0xf77e,0xc71d,0xd73c,
    0x26d3,0x36f2,0x0691,0x16b0,0x6657,0x7676,0x4615,0x5634,
    0xd94c,0xc96d,0xf90e,0xe92f,0x99c8,0x89e9,0xb98a,0xa9ab,
    0x5844,0x4865,0x7806,0x6827,0x18c0,0x08e1,0x3882,0x28a3,
    0xcb7d,0xdb5c,0xeb3f,0xfb1e,0x8bf9,0x9bd8,0xabbb,0xbb9a,
    0x4a75,0x5a54,0x6a37,0x7a16,0x0af1,0x1ad0,0x2ab3,0x3a92,
    0xfd2e,0xed0f,0xdd6c,0xcd4d,0xbdaa,0xad8b,0x9de8,0x8dc9,
    0x7c26,0x6c07,0x5c64,0x4c45,0x3ca2,0x2c83,0x1ce0,0x0cc1,
    0xef1f,0xff3e,0xcf5d,0xdf7c,0xaf9b,0xbfba,0x8fd9,0x9ff8,
    0x6e17,0x7e36,0x4e55,0x5e74,0x2e93,0x3eb2,0x0ed1,0x1ef0 
};

/*******************************************************************************
** 函数名称: INT8U SD_GetCRC16()					
** 功能描述: 计算CRC16								
** 输　  入: INT8U *pSource: 数据					
	     INT16U len    : 长度							
** 输 　 出: CRC16码								
*******************************************************************************/
INT16U SD_GetCRC16(INT8U *pSource,INT16U len)
{
    INT16U i ;
    INT16U result=0 ;
    
    for(i=0;i<len;i++)
        result=(result<<8)^(INT16U)CRCTable[(result>>8)^ *pSource++];
    
    return result ;
}

/*******************************************************************************
** 函数名称: INT8U SD_GetCmdByte6()					
** 功能描述: 获取SD卡命令的CRC7						
** 输　  入: INT8U cmd   : 命令						
	     INT8U *param: 命令的参数,长度为4字节			 
** 输 　 出: CRC7码									
*******************************************************************************/
INT8U SD_GetCmdByte6(INT8U cmd,INT8U *param)
{
    INT8U i,j ;
    INT8U reg=0 ;
    INT8U array[5];
    
    array[0]=cmd ;
    /* 将参数的顺序重新排列 */
    for(i=1;i<5;i++)
        array[i]=param[4-i];
    
    /* 计算5个字节的CRC7 */
    for(i=0;i<5;i++)
    {
        for(j=0;j<8;j++)
        {
            reg<<=1 ;
            reg^=( (((array[i]<<j)^reg)&0x80)?0x9:0 );
        }
    }
    
    return((reg<<1)+0x01);
    /* 计算结果的CRC7左移一位,并将最低位置1 */
}
/*******************************************************************************
** 函数名称: INT8U SD_GetCRC7()						
** 功能描述: 计算 CRC7								
** 输　  入: INT8U *pSource: 数据					
	         INT16U len    : 数据长度					
** 输 　 出: CRC7码									
*******************************************************************************/
INT8U SD_GetCRC7(INT8U *pSource,INT16U len)
{
    INT8U i=0,j ;
    INT8U reg=0 ;
    
    do 
    {
        for(j=0;j<8;j++)
        {
            reg<<=1 ;
            reg^=((((pSource[i]<<j)^reg)&0x80)?0x9:0);
        }
        i++;
    }
    while(i<len);
    return reg ;
}

#endif