汇编源程序.asm

4-20MA信号发生器

		ORG	00H
		AJMP	START
START:		MOV	P1,#0FFH	//各口置初值
		MOV	P3,#0FFH
		MOV	R5,#00H
		MOV	33H,#00H	//显示缓冲置初值	
		MOV	34H,#04H
		MOV	35H,#00H
		MOV	SCON,#00H	//置串口为移位寄存器方式
		ACALL	DISP		//调显示子程序
WT:		JB	P3.3,DE		//加按键是否按下
		ACALL	DELAY10MS	//去抖动
		JB	P3.3,DE
		DEC	R5
		MOV	P1,R5		//有键按下,P1口减1
		MOV	A,R5
		CPL	A		//A取反
		MOV	B,#10H		//除以16
		DIV	AB
		MOV	33H,B		//余数送33H
		ADD	A,#04H
		DA	A
		MOV	R3,A
		ANL	A,#0FH		//屏蔽高4位
		MOV	34H,A		//个位送34H
		MOV	A,R3
		ANL	A,#0F0H		//屏蔽低4位
		RL	A
		RL	A		//左移4次
		RL	A
		RL	A
		MOV	35H,A		//十位送35H
		ACALL	DISP		
DE:		JB	P3.4,WT		//减按键是否按下
		ACALL	DELAY10MS
		JB	P3.4,WT
		INC	R5
		MOV	P1,R5
		MOV	A,R5
		CPL	A
		MOV	B,#10H
		DIV	AB
		MOV	33H,B
		ADD	A,#04H
		DA	A
		MOV	R3,A
		ANL	A,#0FH
		MOV	34H,A
		MOV	A,R3
		ANL	A,#0F0H
		RL	A
		RL	A
		RL	A
		RL	A
		MOV	35H,A
		ACALL	DISP
		AJMP	WT
DISP:		MOV	R0,#33H		//显示子程序
		MOV	R7,#03H
		MOV	A,@R0
		MOV	DPTR,#TAB
		MOVC	A,@A+DPTR
		MOV	SBUF,A
		JNB	TI,$
		CLR	TI
		MOV	R0,#34H
		MOV	A,@R0
		MOV	DPTR,#TAB1
		MOVC	A,@A+DPTR
		MOV	SBUF,A
		JNB	TI,$
		CLR	TI
		MOV	R0,#35H
		MOV	A,@R0
		MOV	DPTR,#TAB1
		MOVC	A,@A+DPTR
		MOV	SBUF,A
		JNB	TI,$
		CLR	TI
		RET
TAB:		DB	0FCH,60H,60H,0DAH,0DAH,0F2H,66H,66H,0B6H,0BEH,0E0H,0E0H,0FEH,0FEH,0F6H
TAB1:		DB	0FCH,60H,0DAH,0F2H,66H,0B6H,0BEH,0E0H,0FEH,0F6H			
DELAY10MS:	MOV	R6,#100
D1:		MOV	R7,#248
		DJNZ	R7,$
		DJNZ	R6,D1
		RET
		END