delayms.a51

USB2.0原理与工程开发光盘(第二版)

$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