mcrc.src

关于温度传感器和电机测速的单片机程序

NAME	MCRC

?PR?_m_CRC?MCRC      SEGMENT CODE INBLOCK 
	PUBLIC	_m_CRC

	RSEG  ?PR?_m_CRC?MCRC
_m_CRC:
	USING	0
;CRC0 'R7' ----
;InByt'R5' ----
	MOV	A,R5
	PUSH 	ACC 		;save bits to be shifted
	MOV 	B,#8 		;set shift = 8 bits ;
CRC_LOOP: 
	XRL 	A,R7 		;calculate CRC
	RRC 	A 		;move it to the carry
	MOV 	A,R7 		;get the last CRC value
	JNC 	ZERO 		;skip if data = 0
	XRL 	A,#18H 		;update the CRC value;
ZERO: 	RRC 	A 		;position the new CRC
	MOV 	R7,A 		;store the new CRC
	POP 	ACC 		;get the remaining bits
	RR 	A 		;position the next bit
	PUSH 	ACC 		;save the remaining bits
	DJNZ 	B,CRC_LOOP 	;repeat for eight bits
	POP 	ACC 		;clean up the stack
;	MOV	AR7,R5
	RET
	END