uint16 crc16l(unsigned char *buf,uint16 len)
{
unsigned int crc=0x0000;
unsigned short c,i;
while(len!=0)
{
c=*buf;
for(i=0;i<8;i++)
{
if((crc ^ c) & 1)
crc=(crc>>1)^0xa001;
else
crc>>=1;
c>>=1;
}
len--;
buf++;
}
return crc;
}