usbrw.a51

基于USB接口的GPS驱动程序.gps后段接受以及输出,及usp驱动读写

;*********************************************************************************
; Module description:
;   This file is used to read/write USB regs, 
;   It is written in ASM in order to fast the access
;
;
;Author : Yu Lu ,
;         [e-mail]
;
;*********************************************************************************/


NAME   USBRW_MD
PUBLIC _read_usb, _write_usb, _bunch_read_usb, _bunch_write_usb

USING 0
SUB_USBRW  SEGMENT CODE
DAT_USBRW  SEGMENT DATA OVERLAYABLE

;AUXR1 EQU 0A2H // this is old control register of dual DPTRs in AT89C51RB2
DPS    EQU 86H  ; this is control register of dual DPTRs in DS89C420 
                ; ID1: DPS.7
                ; ID0: DPS.6
                ; TSL: DPS.5
                ; AID: DPS.4
                ; SEL: DPS.0
DPH1   EQU 85H
DPL1   EQU 84H  

EXTRN CODE (ser_dispchar)

	RSEG DAT_USBRW
TEMP:  DS 1
	RSEG SUB_USBRW

;***************************************************************
; This subroutine is used to access USBN9603 regs , read
; USAGE:     char read_usb(unsigned int usbadr);
; Argument : 
;           INPUT:   R6&R7: address of USBN9603's reg
;           OUTPUT:  R7: value of that reg
;***************************************************************
_read_usb:
	PUSH DPH
	PUSH DPL

        MOV  DPH, R6 
	MOV  DPL, R7
	MOVX  A, @DPTR
	MOV  R7,A

	POP  DPL
	POP  DPH
	RET

;***************************************************************
; This subroutine is used to access USBN9603 regs ,write
; USAGE:     write_usb(unsigned int usbadr, char dta);
; Argument  :
;           INPUT: 
;                 R6&R7: address of USBN9603's reg
;                 R5   : value to be written
;          OUTPUT: 
;                 none;
;***************************************************************
_write_usb:
	PUSH DPH
	PUSH DPL

	MOV  DPH, R6
	MOV  DPL, R7
	MOV  A,R5
	MOVX @DPTR, A

	POP  DPL
	POP  DPH
	RET

;***************************************************************
;This subroutine is used to read a bundle of data from USBN9603's reg
;usually from the data FIFO
; USAGE     : bunch_read_usb( unsigned int usbadr, unsigned int datadd, unsigned char count)
; Argument  :
;           INPUT:
;                R6&R7 : address of USBN9603's reg
;                R3    : count of data
;;         OUTPUT: 
;                R4&R5 : address of the data array
;***************************************************************
_bunch_read_usb:
	PUSH  DPH
	PUSH  DPL
	
	CJNE  R3, #00, BUN_R1   ; if the count is 0, do nothing

	RET
BUN_R1:
	MOV   DPS, #04
	MOV   DPH, R6           ; set the address of USBN9603
	MOV   DPL, R7 

	INC   DPS               ; toggle DPTR

	MOV   DPH1, R4          ;set address of xram
	MOV   DPL1, R5 
BUN_R0:
	INC   DPS               ; back to USBN9603 
	MOVX   A, @DPTR         ; read from fifo
	INC   DPS               ; back to xram
	MOVX   @DPTR, A         ; write data to xram
	INC   DPTR              ; point to next xram addr
	DJNZ  R3,  BUN_R0       ; if not done, 	
        
	INC   DPS
	POP   DPL
	POP   DPH
	RET
;***************************************************************
;This subroutine is used to write a bundle of data to USBN9603's reg
; usually to the data FIFO
; USAGE     : bunch_write_usb( unsigned int usbadr, unsigned int datadd, unsigned char count)     
; Argument  :
;           INPUT: 
;                 R6&R7: address of USBN9603's reg
;                 R4&R5: address of the data array
;                 R3:    count of data
;***************************************************************
_bunch_write_usb:

	PUSH  DPH
	PUSH  DPL

	CJNE  R3, #00, BUN_S1  ; if the count is 0 , do nothing
	RET
BUN_S1:

	MOV DPS, #04
	MOV DPH,R6           ; set the address of USBN9603
	MOV DPL,R7
 
	INC DPS              ; toggle DPTR

        MOV DPH1, R4          ; set the address of xram
        MOV DPL1, R5

BUN_S0:
	MOVX A, @DPTR        ; get the data from xram
        INC DPTR             ; xram DPTR ++
	INC DPS            ; toggle back DPTR
	MOVX @DPTR, A        ; send data to USBN9603
	INC  DPS            ; toggle back DPTR
	DJNZ  R3, BUN_S0

 	INC DPS            ; recover the original DPTR
	
	POP  DPL
	POP  DPH

	RET

END