16位数据拆分成2个8位数据例子：

unsigned int _16wei;
unsigned char gao8,di8;
gao8	= (_16wei >> 8) & 0xff; 
di8	= _16wei & 0xff;

unsigned int _16wei;
unsigned char gao8,di8;
_16wei	= (gao8 << 8) | di8;