crc._c

AVR16源代码 ICC编译器

#include	<iom16v.h>
#include	"Crc.h"

//============================================================
//函	数：unsigned short CRC16(unsigned char *Message, int Len)
//功	能：CRC16计算
//入口参数：Message 要进行CRC16计算字符串，Len字符串长度  
//返 回 值：CRC16计算结果  
//设 计 者：覃道堂 
//创作时间：2004-03-30
//修改时间：
//修改目的：
//============================================================
unsigned int  BlockCRC16UsingAlgorithm(unsigned char *Block, unsigned int Len)
{
   unsigned int CRC;
   unsigned int uiCharShifted;
   unsigned int i;
   unsigned char v;

   CRC = 0;
   for (i=0; i<Len; i++)
     {
     uiCharShifted = ((unsigned int)(Block[i]) & 0x00FF) << 8;
     CRC = (CRC) ^ uiCharShifted;
     for (v = 0; v < 8; ++v)
       {
       if ( CRC & 0x8000 )
         CRC = (CRC << 1) ^ 0x1021;
       else
         CRC = CRC << 1;
       }
     CRC = CRC & 0xFFFF;
     }
     // ByteCRC16UsingAlgorithm(CRC, Block[i]);
   return CRC;
}
//============================================================
//函	数：unsigned char Verify_Command(unsigned char *ReceiveBuf,int Len)
//功	能：CRC校验处理
//入口参数：校验数据，校验数据长度
//返 回 值：0校验成功。否则不正确
//设 计 者：覃道堂 
//创作时间：2006-03-16
//修改时间：
//修改目的：
//============================================================
unsigned char Verify_Command(unsigned char *ReceiveBuf,int Len)
{
	unsigned short 	Crc_Tmp;

	if(ReceiveBuf[4] != (Len - 2))//整包数据长度减去校验和为命令长度
		return 1;

	Crc_Tmp = ReceiveBuf[Len-2]*0x100 + ReceiveBuf[Len-1];
	
	if((CRC16(ReceiveBuf, Len-2)) !=Crc_Tmp)
		return 3;
	return 0;
}