门铃.asm

51的是门铃程程序是汇编程序

;***** 通过1*4按键的第3号键按下可听到门铃的声音     
       T5HZ EQU 30H
       T7HZ EQU 31H
       T05SA EQU 32H
       T05SB EQU 33H
       FLAG BIT 00H
       STOP BIT 01H
       SP1 BIT P1.0
       ORG 0000H
       LJMP START
       ORG 000BH
       LJMP INT_T0
START: MOV TMOD,#02H
       MOV TH0,#06H
       MOV TL0,#06H
       SETB ET0
       SETB EA
NSP:   JB SP1,NSP
       LCALL DELY10MS
       JB SP1,NSP
       SETB TR0
       MOV T5HZ,#00H
       MOV T7HZ,#00H
       MOV T05SA,#00H
       MOV T05SB,#00H
       CLR FLAG
       CLR STOP
       JNB STOP,$
       LJMP NSP
DELY10MS: MOV R6,#20
D1:    MOV R7,#248
       DJNZ R7,$
       DJNZ R6,D1
       RET
INT_T0:INC T05SA
       MOV A,T05SA
       CJNE A,#100,NEXT
       MOV T05SA,#00H
       INC T05SB
       MOV A,T05SB
       CJNE A,#20,NEXT
       MOV T05SB,#00H
       JB FLAG,STP
       CPL FLAG
       LJMP NEXT
STP:   SETB STOP
       CLR TR0
       LJMP DONE
NEXT:  JB FLAG,S5HZ
       INC T7HZ
       MOV A,T7HZ
       CJNE A,#03H,DONE
       MOV T7HZ,#00H
       CPL P3.7
       LJMP DONE
S5HZ:  INC T5HZ
       MOV A,T5HZ
       CJNE A,#04H,DONE
       MOV T5HZ,#00H
       CPL P3.7
       LJMP DONE
DONE:  RETI
       END