bcd273.asm

来自「BCD码波盘 BCD码波盘」· 汇编 代码 · 共 73 行

;读BCD码拨盘程序 
;4 位BCD码存放30H~33H

		ORG		0000H
		AJMP	MAIN
		ORG		0030H
MAIN:	CLR		P3.0												   
		CLR		P3.1
		MOV		R0,#30H
		CLR		P3.6
		MOV		P0,#0FFH
		CLR		P2.7
 		CLR		P2.6
		CLR		P2.5

		ACALL	GET_BCD
		SETB	P2.7
		ACALL	GET_BCD
		ACALL	DISPLAY
		AJMP	MAIN
GET_BCD:
		MOV		A,P0 
		ANL		A,#0FH
		MOV		@R0,A
		INC		R0
		MOV		A,P0
		SWAP	A
		ANL		A,#0FH
		MOV		@R0,A
		CJNE	R0,#33H,OUT
		RET
OUT:	INC		R0
		RET
DISPLAY:SETB	P3.6
		MOV		R2,#0FEH
		MOV		R1,#4
		MOV		R0,#30H
DISP1:	MOV		P0,R2
		SETB	P3.0
		CLR		P3.0
		MOV		A,@R0
		MOV 	DPTR,#NUMTAB
		MOVC	A,@A+DPTR
		MOV		P0,A
		SETB	P3.1
		CLR		P3.1
		ACALL	D1MS
		MOV		A,R2
		RL		A
		MOV		R2,A
		INC		R0
	    MOV		P0,#00H
		SETB	P3.1
		CLR		P3.1
		DJNZ	R1,DISP1
		RET	   
D1MS:	MOV		R3,#2
		MOV		R4,#25
		DJNZ	R4,$
		DJNZ	R3,$-4
		RET
NUMTAB:	DB      03FH;0
        DB      006H;1
        DB      05BH;2
        DB      04FH;3
        DB      066H;4
        DB      06DH;5
        DB      07DH;6
        DB      007H;7
        DB      07FH;8
        DB      06FH;9	
		END