;步進(jìn)電機(jī)正轉(zhuǎn)，反轉(zhuǎn)各3圈
;***************************************************************************
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;*  Create by :石學(xué)軍      www.51c51.com 更多例程請登陸網(wǎng)站        	   *
;***************************************************************************
org 00h
x1:mov r3,#250
start:mov r0,#00h
start1:
mov p1,#0ffh
mov a,r0
mov dptr,#table
movc a,@a+dptr
jz start
cpl a
mov p1,a
call delay
inc r0
djnz r3,start1
mov r3,#250
start2:
mov p1,#0ffh
 mov r0,#05
start3:mov a,r0
mov dptr,#table
movc a,@a+dptr

jz start2
cpl a
mov p1,a
call delay
inc r0
djnz r3,start3
jmp x1
delay:	mov r5,#40;延時。
d1: 	mov r6,#10
d2:	mov r7,#18
	djnz r7,$
	djnz r6,d2
	djnz r5,d1
	ret
table:
db 03h,09h,0ch,06h
db 00
db 06h,0ch,09h,03h
db 00
end