ezbulk.a51

A Simple bulk transfer. Example code of the EZ-USB

;--------------------------------------------------------------
; ezbulk.A51 6-17-98   LTH
;
; A Simple bulk transfer.  Updated and corrected version of the
; example code on page 81 of the EZ-USB TRM v1.0.  Use this to study bulk transfers
; between the EZ-USB Development Board and the Anchor Control Panel.
;
; 1. Fills the EP2IN buffer with a decrementing count from 64 to 1.
; 2. Maintains counts of number of IN and OUT transfers to EP2.
; 3. Does nothing with the data received over EP2OUT.
; 4. Updates the first two bytes of the EP2IN buffer with the number
;    of EP2IN transfers (byte 0) and the number of OUT transfers (byte 1).
;
; To exercise with the Anchor control panel:
; 1. Download the code, either from the Keil environment or by clicking the 
;    'Download' button and selecting ezbulk.hex.
; 2. Set Interface 0, alternate setting 1.  This establishes the EP2 endpoints
;    with MaxPacketSizes of 64.
; 3. Select Endpoint 2 IN in the Bulk Transfer button bar.
; 4. Click the Blk Trans button.  You should see the 64 bytes decrementing from 
;    64 to 1.
; 5. Click Blk Trans button again to perform another EP2IN transfer.  The pattern
;    should now be the same except for byte 0, which indicates 1 IN transfer has
;    previously happened.  Each click of BlkTrans button with EP2IN selected transfers
;    another 64 bytes with the first byte incrementing.
; 6. Select Endpoint 2 OUT in the Bulk Transfer button bar.
; 7. Click BlkTrans.  This sends 64 bytes to EP2OUT.  The data is ignored.
; 8. Select Endpoint 2 IN, click BlkTrans.  The second byte should now be 1, indicating
;    that one EP2OUT transfer has previously happened. 
;
; This code polls the endpoint busy bits.  A more advanced example would use the vectored
; interrupts.
;--------------------------------------------------------------
$NOMOD51		; disable predefined 8051 registers
$nolist
$include (..\..\..\target\inc\ezregs.inc)	; EZ-USB register assignments
$list
;
NAME	        ezbulk
;
		ISEG AT 60H		; stack (this app doesn't use it)
stack:		ds	20
;
		CSEG AT 0
 		ljmp	start
; -------------------------------------------------
		org	200h		
; -------------------------------------------------
start:		mov	SP,#STACK-1	; set stack
		mov	dptr,#IN2BUF
 		mov	r7,#64		; fill EP2IN buffer with 64 bytes
fill:		mov	a,r7
		movx	@dptr,a
 		inc	dptr
  		djnz	r7,fill		; load decrementing counter starting w. 64
;
		mov	r1,#0		; count the IN transfers
 		mov	r2,#0		; count the OUT transfers
  		mov	dptr,#IN2BC	; load the IN2 Byte Count register
   		mov	a,#64		; 64 bytes
    		movx	@dptr,a		; arm the IN transfer
;
loop:		mov	dptr,#IN2CS	; EP2IN Control & Status register
		movx	a,@dptr
 		jnb	acc.1,service_IN2 ; check the busy bit, service if LOW
  		mov	dptr,#OUT2CS	; EP2OUT Control & Status reg
   		movx	a,@dptr
    		jb	acc.1,loop	; busy-keep checking
;
service_OUT2:	inc	r2		; OUT packet counter
		mov	dptr,#IN2BUF+1	; load OUT packet count into second IN2BUF byte
 		mov	a,r2
  		movx	@dptr,a
		mov	dptr,#OUT2BC	; load anything to byte count to re-arm
 		mov	a,#1		; any value
 		movx	@dptr,a		
  		sjmp	loop
;
service_IN2:	inc	r1		; IN packet countr
		mov	dptr,#IN2BUF
 		mov	a,r1		; load IN packet count into first IN2BUF byte
  		movx	@dptr,a
      		mov	dptr,#IN2BC	; load the EP2IN byte count to re-arm IN transfer
       		mov	a,#64		; 64 byte payload
       		movx	@dptr,a
       		sjmp	loop	
;
		END