p15_1.asm

单片机原理与应用实例教程 单片机原理与应用实例教程

		SPK	 EQU P2.3
		ORG 0000H
		LJMP MAIN
		ORG 000BH
		LJMP INT_T0
		ORG 3000H

S_TH:	DB 0FCH, 0FCH, 0FDH, 0FDH, 0FDH, 0FDH, 0FEH, 0FEH
S_TL:	DB 044H, 0ACH, 009H, 034H, 082H, 0C8H, 006H, 022H

MAIN:	MOV TMOD, #01H
		MOV TH0, #0FCH
		MOV TL0, #044H
		MOV R0, #0H
		CLR SPK
		SETB EA
		SETB ET0
		SETB TR0
LOOP:	INC R0
		CJNE R0, #8, NEXT
		MOV R0, #0H
NEXT:	ACALL DELAY
		AJMP LOOP

INT_T0:	CPL SPK
		MOV DPTR, #S_TH
		MOV A, R0
		MOVC A, @A+DPTR
		MOV TH0, A
		MOV DPTR, #S_TL
		MOV A, R0
		MOVC A, @A+DPTR
		MOV TL0, A
		RETI

DELAY: 	MOV R5, #0FFH
DL1:	MOV R6, #082H
DL2:	MOV R7, #005H
DL3:	DJNZ R7, DL3
		DJNZ R6, DL2
		DJNZ R5, DL1
		RET

		END