renum.a51

fx2 gpifFIFOREAD方式实现高速数据传输数据固件

NAME		RENUM
PUBLIC		EZUSB_RENUM

$include (..\..\inc\ezregs.inc)

EZUSB		segment	code

		rseg	EZUSB		
EZUSB_RENUM:	mov	dptr,#USBCS
		mov	a,#000001010b	; set DISCON and RENUM
		movx	@dptr,a		; do it
;
; Hold disconnect low for 12 milliseconds (12000 microseconds).
; 10 cycles * 166.6 ns per cycle is 1.66 microseconds per loop.
; 12000 microseconds / 1.66 = 7229.  [assumes 24 MHz clock]
;								
		mov	a, #0			; Clear dps so that we're using dph and dpl!	
		mov	dps, a			; 
		mov	dptr,#(0ffffH - 6024) 	; long pulse for operating
		mov	r4,#5

time12msec:     inc     dptr            ; 3 cycles
		mov     a,dpl           ; 2 cycles
                orl     a,dph           ; 2 cycles
                jnz     time12msec      ; 3 cycles
 		djnz	r4,time12msec
;
		mov	dptr,#USBCS
		mov	a,#00000010b	; discon LO, renum HI
		movx	@dptr,a
		ret
		end