doorbell.asm

做文字显示的

T5HZ		EQU 30H 
T7HZ		EQU 31H 
T05SA		EQU 32H 
T05SB		EQU 33H 
FLAG		BIT 00H 
STOP		BIT 01H 
SP1			BIT P3.7 
			ORG 00H 
			LJMP START 
			ORG 0BH 
			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 P1.0 
			LJMP DONE 
S5HZ:		INC T5HZ 
			MOV A,T5HZ 
			CJNE A,#04H,DONE 
			MOV T5HZ,#00H 
			CPL P1.0 
			LJMP DONE 
DONE:		RETI 
			END