按你電路看，BZ和單片機之間應該接個3級管，不然帶不動，然后BZ的那個電阻應該去掉，不知道你單片機型號，你要用NPN管的話，沒有推挽輸出功能的單片機需要上拉電阻。用PNP管的話，要接VCC那頭，并且驅動蜂鳴器需要 CLR  P1.5

P1.5總給高電平是不會響的，要不斷改變狀態，可以把SETB P1.5改為CPL P1.5

播放 祝你平安

ORG 0000H
LJMP START
ORG 000BH
INC 20H ;中斷服務,中斷計數器加1
MOV TH0,#0D8H
MOV TL0,#0EFH ;12M晶振，形成10毫秒中斷
RETI
START:
MOV SP,#50H
MOV TH0,#0D8H
MOV TL0,#0EFH
MOV TMOD,#01H
MOV IE,#82H
MUSIC0:
NOP
MOV DPTR,#DAT ;表頭地址送DPTR
MOV 20H,#00H ;中斷計數器清0
MOV B,#00H ;表序號清0
MUSIC1:
NOP
CLR A
MOVC A,@A+DPTR ;查表取代碼
JZ END0 ;是00H,則結束
CJNE A,#0FFH,MUSIC5
LJMP MUSIC3
MUSIC5:
NOP
MOV R6,A
INC DPTR
MOV A,B
MOVC A,@A+DPTR ;取節拍代碼送R7
MOV R7,A
SETB TR0 ;啟動計數
MUSIC2:
NOP
CPL P3.3
MOV A,R6
MOV R3,A
LCALL DEL
MOV A,R7
CJNE A,20H,MUSIC2 ;中斷計數器(20H)=R7否?
;不等,則繼續循環
MOV 20H,#00H ;等于,則取下一代碼
INC DPTR
; INC B
LJMP MUSIC1
MUSIC3:
NOP
CLR TR0 ;休止100毫秒
MOV R2,#0DH
MUSIC4:
NOP
MOV R3,#0FFH
LCALL DEL
DJNZ R2,MUSIC4
INC DPTR
LJMP MUSIC1
END0:
NOP
MOV R2,#64H ;歌曲結束,延時1秒后繼續
MUSIC6:
MOV R3,#00H
LCALL DEL
DJNZ R2,MUSIC6
LJMP MUSIC0
DEL:
NOP
DEL3:
MOV R4,#02H
DEL4:
NOP
DJNZ R4,DEL4
NOP
DJNZ R3,DEL3
RET
NOP
DAT:
db 26h,20h,20h,20h,20h,20h,26h,10h,20h,10h,20h,80h,26h,20h,30h,20h
db 30h,20h,39h,10h,30h,10h,30h,80h,26h,20h,20h,20h,20h,20h,1ch,20h
db 20h,80h,2bh,20h,26h,20h,20h,20h,2bh,10h,26h,10h,2bh,80h,26h,20h
db 30h,20h,30h,20h,39h,10h,26h,10h,26h,60h,40h,10h,39h,10h,26h,20h
db 30h,20h,30h,20h,39h,10h,26h,10h,26h,80h,26h,20h,2bh,10h,2bh,10h
db 2bh,20h,30h,10h,39h,10h,26h,10h,2bh,10h,2bh,20h,2bh,40h,40h,20h
db 20h,10h,20h,10h,2bh,10h,26h,30h,30h,80h,18h,20h,18h,20h,26h,20h
db 20h,20h,20h,40h,26h,20h,2bh,20h,30h,20h,30h,20h,1ch,20h,20h,20h
db 20h,80h,1ch,20h,1ch,20h,1ch,20h,30h,20h,30h,60h,39h,10h,30h,10h
db 20h,20h,2bh,10h,26h,10h,2bh,10h,26h,10h,26h,10h,2bh,10h,2bh,80h
db 18h,20h,18h,20h,26h,20h,20h,20h,20h,60h,26h,10h,2bh,20h,30h,20h
db 30h,20h,1ch,20h,20h,20h,20h,80h,26h,20h,30h,10h,30h,10h,30h,20h
db 39h,20h,26h,10h,2bh,10h,2bh,20h,2bh,40h,40h,10h,40h,10h,20h,10h
db 20h,10h,2bh,10h,26h,30h,30h,80h,00H

END

BUZZER  BIT  P1.5