BELL  	BIT  P1.3
LCOUNT1      	DATA 30H	;循環次數1
LCOUNT2 	DATA 31H	;循環次數2

         ORG      8000H
         LJMP     MAIN
	 ORG	  8100H

MAIN: 	 MOV      SP,#80H
	 CALL 	  MUSIC
	 JMP	  MAIN
	
MUSIC:
      MOV 	R7,#0
SLONG:MOV 	DPTR,#SOUND_LONG
      MOV 	A,R7
      MOVC 	A,@A+DPTR
      MOV 	LCOUNT1,A		      ;送發音的長短到LONGT1
      MOV 	A,R7
      MOV       DPTR,#SOUND_TONE
      MOVC 	A,@A+DPTR
      MOV 	LCOUNT2,A		     ;送音符的周期到LCOUNT2／即音的高低
      MOV 	R4,LCOUNT1		;循環 音長
LONG: MOV 	R6,#12    		;循環節拍
MUSI: MOV 	R5,LCOUNT2		;產生音調所需要的方波
MUSI1:CLR 	BELL			     ;開蜂鳴器
      DJNZ 	R5,MUSI1 		    ;開蜂鳴器 音調次后退出
      MOV 	R5,LCOUNT2
MUSI2:SETB 	BELL			    ;關蜂鳴器
      DJNZ 	R5,MUSI2		    ; 關蜂鳴器音調次后退出
      DJNZ 	R6,MUSI
      DJNZ 	R4,LONG
      PUSH 	7
      PUSH 	6
LONGS:CALL 	DELAY
      POP 	6
      POP 	7
      INC 	R7
      CJNE	R7,#40,SLONG
      RET

DELAY:;延時10ms
      MOV 	R7,#90H;
D1:   MOV 	R6,#0A0H;
D0:   NOP
      DJNZ 	R6,D0
      DJNZ 	R7,D1
      RET
SOUND_LONG:                                     ;MUSIC中每一個音符的長度
DB 60,30,30,60,30,30,60,30,120,60
DB 30,30,60,30,30,30,30,30,120,60
DB 30,30,30,30,30,30,30,30,60,30
DB 120,60,60,60,30,30,30,60,30,120
SOUND_TONE:                                     ;MUSIC中每一個音符的音調
DB 142,159,189,142,159,189,142,142,159,142
DB 142,159,189,142,159,189,212,212,239,212
DB 189,189,159,142,120,142,159,189,189,159
DB 239,189,189,189,189,189,142,142,159,142
END