CRC8 校验：
datBuff:8 ;assign 8 byte data buffer
bit_cnt ;bit counting
CRC_COUNT ;number of bytes for CRC
CRC_RESULT ;CRC resulr
crc_temp ;temporary data buffer during CRC
#define skp0 btfsc
#define skp1 btfss
org 0x000
movlw 07H
movwf CRC_COUNT
movlw datBuff
movwf FSR ;FSR point to data buffer
call CRC_CHECK
movwf datBuff+7
goto $
CRC_CHECK clrf CRC_RESULT ;initialize the CRC buffer
crc_00 movlw 08H ;number of bits for one byte
movwf bit_cnt ;set bit counter
movf INDF,w ;get one data byte
movwf crc_temp ;copy to temporary location
crc_01 rrf crc_temp,f ;get LSB in C
skpc ;is this LSB=1?
goto crc_02 ;go if LSB=0
movlw 01H ;do if LSB=1
xorwf CRC_RESULT,f
crc_02 rrf CRC_RESULT,w ;get LSB of CRC
skpc ;test LSB
goto crc_03 ;go if LSB=0
movlw 018H ;do if LSB=1
xorwf CRC_RESULT,f ;polynomial implementation
crc_03 rrf CRC_RESULT,w ;whole byte right rotate
rrf CRC_RESULT,f
decfsz bit_cnt,f ;bit counting
goto crc_01 ;go on until aa 8 bits done
incf FSR,f ;pointer update to next byte
decfsz CRC_COUNT,f ;byte counting
goto crc_00 ;go on until all byte done
movf CRC_RESULT,w ;get CRC, Z set if CRC=0
return ;return with CRC in W
END
