蜂鸣器之兰花草.asm

AT89S52单片机程序50例（00-50）

;蜂鸣器之兰花草
;P1.0接蜂鸣器

      SPK EQU P1.0  ;蜂鸣器所在端口

      ORG 0000H
      JMP START
	
START:MOV R3,#00H  ;R3清零
 NEXT:MOV A,R3  ;A清零，R3为表的偏移量
      MOV DPTR,#TABLE  ;取歌曲表的首地址
      MOVC A,@A+DPTR  ;查表
      JZ START  ;A=0时，跳转至START
      MOV R7,A  ;A的内容给R7，R7存放低地址数据
      INC R3  ;R3加1
      MOV A,R3
      MOVC A,@A+DPTR
      MOV R2,A  ;R2存放高地址数据
      ACALL SONG  ;调用歌曲播放子程序
      INC R3
      SJMP NEXT
	
;===  歌曲播放子程序 ===
 SONG:MOV A,R2  ;取出节拍
      RL A  ;左移
      JNZ KEEP  ;A不为0时，跳转至KEEP
      MOV A,#01H
 KEEP:MOV R2,A
REPEAT:ACALL EIGHTH
       DJNZ R2,REPEAT
  RET
	
;===  产生1/8拍延时子程序  ===		
 EIGHTH:MOV A,R7  ;查表取出廷时参数,保存到R4
        MOV DPTR,#DELAY_T
        MOVC A,@A+DPTR
        MOV R4,A

        MOV A,R7  ;查表取出1/8拍周期数,保存到R5
        MOV DPTR,#S_PARA
        MOVC A,@A+DPTR
        MOV R5,A
NEXTCYC:ACALL SOUND
	DJNZ R5,NEXTCYC
  RET

;===  发声子程序 ===	
SOUND:SETB SPK
      ACALL SDELAY
      CLR SPK
      ACALL SDELAY
  RET
	
;===  延时子程序  ===
SDELAY:MOV A,R4  ;延时值在R4内
       MOV R0,A
   XL2:MOV R1,#03H
   DL1:NOP
       DJNZ R1,DL1
       DJNZ R0,XL2
  RET
	
;===  1/8拍周期表  ===
S_PARA:DS 1DH  ;定义1DH个程序存储器空间
       DB 15H,16H,00
       DB 19H,00H,1CH,00H,1FH,21H,00H,25H
       DB 00H,29H,2CH,00H,31H,34H,37H,00H
       DB 3EH,41H,00H,49H,00H,52H,57H,00H
       DB 62H
	
;===  延时参数表  ===
DELAY_T:DS 1DH  ;定义1DH个程序存储器空间
	DB 7EH,77H,00H
	DB 6AH,00H,5EH,00H,54H,4FH,00H,46H
	DB 00H,3FH,3BH,00H,35H,32H,2FH,00H
	DB 2AH,27H,00H,23H,00H,1FH,1DH,0C0H
	DB 1AH
	
;===  歌曲表  ===
TABLE:DW 2202H,2902H,2902H,2902H,2906H,2702H  ;我从山中来
      DW 2502H,2702H,2502H,2402H,2208H        ;带着兰花草
      DW 2E02H,2E02H,2E02H,2E02H,2E06H,2C02H  ;种在小园中
      DW 2902H,2C02H,2D02H,2A02H,2908H        ;祈祷花开早
      DW 2902H,2E02H,2E02H,2C02H,2906H,2702H  ;一日看三回
      DW 2502H,2702H,2502H,2402H,2206H,1D02H  ;看得花时过
      DW 1D02H,2502H,2502H,2402H,2206H,2902H  ;兰花却依然
      DW 2702H,2502H,2402H,2002H,2208H        ;苞也无一个
      DW 0000H				      ;
	
END