【MCS-51】【A51】LED单灯PWM调光

        LED单灯PWM调光

申明：本程序绝对原创，请转载本博文注明出处：http://blog.csdn.net/fly928sky/article/details/7668663

        1.本程序电路图，请参考http://blog.csdn.net/fly928sky/article/details/7645591

        2.程序中PWM调光的LED灯为DS9

        3.本程序相同流程对应A51程序，请参考http://blog.csdn.net/fly928sky/article/details/7668673

代码如下：

DelayNH	EQU		1000H
DelayNL	EQU		1001H
PwmLowH	EQU		1002H
PwmLowL	EQU		1003H
PwmCylH	EQU		1004H
PwmCylL	EQU		1005H

		ORG		0000H
		LJMP	Start
					 	;程序开始
Start:	ACALL	Init
						;主程序段
Main:	ACALL	PwmM
		LJMP	Main
						;初始化函数
Init:	SETB	P1.1	;关闭数码管
		MOV		P0,#0FFH
		CLR		P1.1
		SETB	P1.3	;关闭点阵
		MOV		P0,#00H
		CLR		P1.3
		RET
						;PWM函数
PwmM:	SETB	P1.2	;LED使能
		MOV		DelayNH,#00H	;延时函数参数DelayN的H位	
		MOV		DelayNL,#00H	;延时函数参数DelayN的L位
		MOV		PwmLowH,#00H	;PwmLow参数H位	
		MOV		PwmLowL,#00H	;PwmLow参数L位
		MOV		PwmCylH,#02H	;PwmCyl参数H位	
		MOV		PwmCylL,#58H	;PwmCyl参数L位
PwmS:	MOV		P0,#0FFH
		ACALL	Delay60000
		ACALL	PwmToBright					//逐渐变亮
		MOV		P0,#07FH
		ACALL	PwmToDark					//逐渐变暗
		LJMP	PwmS	
		RET
						;带参数的延时函数
DelayUS:MOV		R0,DelayNH
		MOV		R1,DelayNL
ULoop:	SETB	C
		MOV		A,R1
		SUBB	A,#00H
		MOV		A,R0
		SUBB	A,#00H
		JC		DUEnd
		MOV   	A,R1    
       	DEC   	R1
       	JNZ   	ULoop
       	DEC   	R0
		SJMP	ULoop
DUEnd:	RET	  

Delay60000:					;0xEA60十进制数为60000
		MOV		DelayNH,#0EAH
		MOV		DelayNL,#060H
		ACALL	DelayUS
		RET

DelayPL:					;参数为PwmLow
		MOV		DelayNH,R2
		MOV		DelayNL,R3
		ACALL	DelayUS
		RET

DelayPCL:					;参数为PwmCyl-PwmLow
		CLR		C			;减法运算
		MOV		A,R5
		SUBB	A,R3
		MOV		DelayNL,A
		MOV		A,R4
		SUBB	A,R2
		MOV		DelayNH,A
		ACALL	DelayUS
		RET
							;逐渐变亮函数
PwmToBright:
		ACALL	PwmInit
		MOV		R3,#01H
PTBS:	MOV		P0,#07FH
		ACALL	DelayPL
		MOV		P0,#0FFH
		ACALL	DelayPCL
							;加1
		CLR		C
		MOV		A,R3
		ADD		A,#01H
		MOV		R3,A
		MOV		A,R2
		ADDC	A,#00H
		MOV		R2,A
							;PwmLow与PwmCyl的比较，PwmLow是否小于PwmCyl
		ACALL	CylCLow
		JC		PTBEnd		;判断CY是否有借位，有借位直接结束函数，否则继续下一条指令
		JNZ		PTBS		;判断差值的H位和L位相或值是否等于零，不等于零跳转到PTBS，否则继续下一条指令
PTBEnd:	RET
							;逐渐变暗函数
PwmToDark:
		ACALL	PwmInit
		CLR		C			;将PwmCyl-1赋给PwmLow
		MOV		A,R5
		SUBB	A,#01H
		MOV		R3,A		;PwmCyl减1后将L位赋值给PwmLowL
		MOV		A,R4
		SUBB	A,#00H
		MOV		R2,A	   	;PwmCyl减1后将H位赋值给PwmLowH

PTDS:	MOV		P0,#07FH
		ACALL	DelayPL
		MOV		P0,#0FFH
		ACALL	DelayPCL
							;减1
		CLR		C			;PwmLow-1
		MOV		A,R3
		SUBB	A,#01H
		MOV		R3,A		;减1后PwmLowL
		MOV		A,R2
		SUBB	A,#00H
		MOV		R2,A	   	;减1后PwmLowH
							;判断PwmLow是否大于1
		JC		PTDEnd		;判断CY是否有借位，有借位直接结束函数，否则继续下一条指令
		MOV		A,R2
		JNZ		PTDS		;PwmLow的H位不为零跳转到PTDS，否则继续下一条指令
		MOV		A,R3	
		CJNE	A,#01H,LowCOne	;PwmLow的L位不等于1跳转到LowCOne，否则继续下一条指令
		LJMP	PTDEnd			;PwmLow的L位等于1跳转到PTDEnd结束函数
LowCOne:JNC		PTDS		;判断CY是否有为零，为零（PwmLow大于1）跳转到PTDS，否则继续下一条指令
		
PTDEnd:	RET

PwmInit:
		MOV		R2,PwmLowH
		MOV		R3,PwmLowL
		MOV		R4,PwmCylH
		MOV		R5,PwmCylL
		RET
							;PwmLow与PwmCyl的比较
CylCLow:
		CLR		C			;减法运算
		MOV		A,R5
		SUBB	A,R3
		MOV		1010H,A		;减法低位结果暂存1010H中
		MOV		A,R4
		SUBB	A,R2
		ORL		A,1010H		;将低位与高位相或存入累加器A
		RET
		 				;程序结束
		END