dac08.asm

程序为达盛实验箱所带

;learn how to operate the I/O ports,how to  control motor

	.mmregs
	.global	_main
	
	.text
_main:
	stm		3000h,sp
	stm		1000h,ar1  ;define the address
	
;start palse  00h=0v 	
	st		00h,*ar1
	portw	*ar1,01h 
	portw	*ar1,00h
	nop 
	nop
	call delaya
	nop
	nop
	
loop:	
;positive pulse  +5v  
	st		00ffh,*ar1
	portw	*ar1,01h 
	portw	*ar1,00h
	nop 
	nop
	call	delay
	nop
	nop   ; set break point here to stop motor
;reverse pulse  0v
	st		0000h,*ar1
	portw	*ar1,01h 
	portw	*ar1,00h
	nop
	nop 
	call	delayb
	nop
	nop
    b loop
    nop
    nop
;----------------------------    
delay: 
	stm 	0400h,ar3
loop1:              
	stm 	08h,ar4
loop2:
	banz 	loop2,*ar4-
	banz 	loop1,*ar3-
	ret
	nop
	nop
;------------------------------	    
delayb: 
	stm 	100h,ar3
loopb1:              
	stm 	080h,ar4
loopb2:
	banz 	loopb2,*ar4-
	banz 	loopb1,*ar3-
	ret
	nop
	nop 

;-------------------------------
delaya: 
	stm 	4000h,ar3
loopa1:              
	stm 	080h,ar4
loopa2:
	banz 	loopb2,*ar4-
	banz 	loopb1,*ar3-
	ret
	nop
	nop     
    .end