原理图在 http://hi.baidu.com/%CD%F5%C1%BC%C5%DC/blog/item/5d4e2002f97282027aec2c60.html
这个程序中为何没有写T1(P3.5)中断的入口地址



MOV 20H,#00H ;20H单元置初值，电机正转位置指针

MOV 21H,#00H ;21H单元置初值，电机反转位置指针

MOV P1,#0C0H ;P1口置初值，防止电机上电短路

MOV TMOD,#60H ;T1计数器置初值,开中断

MOV TL1,#0FFH

MOV TH1,#0FFH

SETB ET1

SETB EA

SETB TR1

SJMP $

;***********计数器1中断程序************

IT1P: JB P3.7,FAN ;电机正、反转指针

;*************电机正转*****************

JB 00H,LOOP0

JB 01H,LOOP1

JB 02H,LOOP2

JB 03H,LOOP3

JB 04H,LOOP4

JB 05H,LOOP5

JB 06H,LOOP6

JB 07H,LOOP7

LOOP0: MOV P1,#0D0H

MOV 20H,#02H

MOV 21H,#40H

AJMP QUIT

LOOP1: MOV P1,#090H

MOV 20H,#04H

MOV 21H,#20H

AJMP QUIT

LOOP2: MOV P1,#0B0H

MOV 20H,#08H

MOV 21H,#10H

AJMP QUIT

LOOP3: MOV P1,#030H

MOV 20H,#10H

MOV 21H,#08H

AJMP QUIT

LOOP4: MOV P1,#070H

MOV 20H,#20H

MOV 21H,#04H

AJMP QUIT

LOOP5: MOV P1,#060H

MOV 20H,#40H

MOV 21H,#02H

AJMP QUIT

LOOP6: MOV P1,#0E0H

MOV 20H,#80H

MOV 21H,#01H

AJMP QUIT

LOOP7: MOV P1,#0C0H

MOV  20H,#01H

MOV 21H,#80H

AJMP QUIT

;***************电机反转*****************

FAN: JB 08H,LOOQ0

JB 09H,LOOQ1

JB 0AH,LOOQ2

JB 0BH,LOOQ3

JB 0CH,LOOQ4

JB 0DH,LOOQ5

JB 0EH,LOOQ6

JB 0FH,LOOQ7

LOOQ0: MOV P1,#0A0H

MOV 21H,#02H

MOV 20H,#40H

AJMP QUIT

LOOQ1: MOV P1,#0E0H

MOV 21H,#04H

MOV 20H,#20H

AJMP QUIT

LOOQ2: MOV P1,#0C0H

MOV 21H,#08H

MOV 20H,#10H

AJMP QUIT

LOOQ3: MOV P1,#0D0H

MOV 21H,#10H

MOV 20H,#08H

AJMP QUIT

LOOQ4: MOV P1,#050H

MOV 21H,#20H

MOV 20H,#04H

AJMP QUIT

LOOQ5: MOV P1,#070H

MOV 21H,#40H

MOV 20H,#02H

AJMP QUIT

LOOQ6: MOV P1,#030H

MOV 21H,#80H

MOV 20H,#01H

AJMP QUIT

LOOQ7: MOV P1,#0B0H

MOV 21H,#01H

MOV 20H,#80H

QUIT: RETI

END