单片机电子琴电路结构及工作原理 第4页
DELAY:MOV R7,#100 ;延长时间等待，键盘消抖
D1: MOV R6,#10
D2: DJNZ R6,D2
DJNZ R7,D1
RET
END
生日快乐歌：（扩展功能部分程序）
ORG 0000H
JMP MAIN
ORG 000BH
JMP TT0
MAIN: MOV TMOD,#01H ；设置定时器0工作方式
MOV IE,#82H ；设置中断
MAIN0:MOV 30H,#00H
NEXT: MOV A,30H
MOV DPTR,#TABLE ；查表
MOVC A,@A+DPTR
MOV R2,A
JZ STOP
ANL A,0FH
MOV R5,A
MOV A,R2
SWAP A
ANL A,#0FH
JNZ SING
CLR TR0
JMP W1
SING: DEC A
MOV 22H,A
RL A
MOV DPTR,#TABLE1 ；查表
MOVC A,@A+DPTR
MOV TH0,A
MOV 21H,A
MOV A,22H
RL A
INC A
MOVC A,@A+DPTR
MOV TL0,A
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JMP NEXT
STOP: CLR TR0
JMP MAIN0
TT0: PUSH ACC ；中断服务程序
PUSH PSW
MOV TL0,20H
MOV TH0,21H
CPL P1.0
POP PSW
POP ACC
RETI
DELAY:MOV R7,#2 ；延时187ms
W2: MOV R4,#187
W3: MOV R3,#248
DJNZ R3,$
DJNZ R4,W3
DJNZ R7,W2
DJNZ R5,DELAY
RET
TABLE1:DW 64260,64400,64524,64580 ；音符计数植
DW 64684,64777,64820,64898
DW 64968,65030,65058,65110
DW 65157,65178,65217
TABLE:DB 82H,01H,81H,94H,84H ；节拍表
DB 0B4H,0A4H,04H
DB 82H,01H,81H,94H,84H
DB 0C4H,0B4H,04H
DB 82H,01H,81H,0F4H,0D4H
DB 0B4H,0A4H,94H
DB 0E2H,01H,0E1H,0D4H,0B4H
DB 0C4H,0B4H,04H
DB 82H,01H,81H,94H,84H
DB 0B4H,0A4H,04H