display.asm

基于UCM40的超声波测距函数,可测0.08---2.5米距离,数值精确

			NAME	DISPLAY
?PR?_DISPLAY?DISPLAY	SEGMENT	CODE
?CO?_DISPLAY?DISPLAY	SEGMENT	DATA
			EXTRN	CODE	(_DELAY)
			PUBLIC	_DISPLAY
			RSEG	?CO?_DISPLAY?DISPLAY
?_DISPLAY?BYTE:
DISPBIT:		DS	1
DISPNUM:		DS	1
			RSEG	?PR?_DISPLAY?DISPLAY
_DISPLAY:		PUSH	ACC
			PUSH	DPH
			PUSH	DPL
			PUSH	PSW
			INC	DISPNUM
			MOV	A,DISPNUM
			CJNE	A,#4D,DISP1
DISP1:			JC	DISP2
			MOV	DISPNUM,#00H
			MOV	DISPBIT,#0FEH
DISP2:			MOV	A,R1
			ADD	A,DISPNUM
			MOV	R0,A
			MOV	A,@R0
			MOV	DPTR,#DISPTABLE
			MOVC	A,@A+DPTR
			MOV	P0,A
			MOV 	A,DISPNUM
			CJNE	A,#2D,DISP3
			CLR	P0.7
DISP3:			MOV	P2,DISPBIT
			MOV	R6,#00H
			MOV	R7,#0AH
			LCALL	_DELAY
			MOV	P0,#0FFH
			MOV	P2,#0FFH
			MOV	A,DISPBIT
			RL	A
			MOV	DISPBIT,A
			POP	PSW
			POP	DPL	
			POP	DPH
			POP	ACC
			RET
DISPTABLE:DB		0C0H,0F9H,0A4H,0B0H,99H,92H,82H,0F8H,80H,90H,88H,83H,0C6H,0A1H,86H,8EH,0BFH,0FFH
			END