delayms.a51

来自「学习USB2.0驱动程序设计源码」· A51 代码 · 共 45 行

$NOMOD51 

NAME		DELAY1MS
PUBLIC		EZUSB_DELAY1MS, EZUSB_SUSP 

$include (testregs.inc)

EZUSB		segment	code
EZUSB1		segment	code

		rseg	EZUSB		
EZUSB_DELAY1MS:
		mov	a, #0		
		mov	dps, a		
		mov	dptr,#(0ffffH - 602)
		mov	r4,#5

loop:	     	inc     dptr         
		mov     a,dpl        
                orl     a,dph        
                jnz     loop		
;
er_end:		ret


		rseg	EZUSB1		
EZUSB_SUSP:	
        mov     dptr,#WAKEUPCS     
	movx	a,@dptr		 
	orl	a,#0C0H   
	movx	@dptr,a

        mov     dptr,#SUSPEND   
        movx    @dptr,a         

	orl	PCON,#00000001b	  

	nop			  
	nop			  
	nop			  
	nop
	nop
er_end1:	ret

end