eziso.a51

A Simple isochronous transfer. Reads 8051 ports A,B and C, and continuously sends a five byte packet

;-----------------------------------------------------------------
; eziso.A51 6-17-98   LTH
;
; A Simple isochronous transfer.  Reads 8051 ports A,B and C, and
; continuously sends a five byte packet over EP8IN:  
;
; Byte0:	Frame Count H
; Byte1:	Frame Count L
; Byte2:	PORTA pins
; Byte3:	PORTB pins
; Byte4:	PORTC pins
;
; You can observe and study USB Isochronous transfers using this code with
; the Using the EZ-USB development board with the Anchor Control Panel.
; The code illustrates how to transport IO PORT data to the isochronous
; endpoint buffer EP8IN.  For simplicity the interrupt system is not used,
; instead the SOF (Start of Frame) bit is polled to detect the arrival of 
; and SOF token.
;
; To use with the Anchor Control Panel:
; 1. Download 'eziso.hex'.  
; 2. On the Iso Trans bar, set: 
;	Pipe to '7:Endpoint 8 IN'
;       PktCount=1
;	PktSize=5
; 	BuffCount=1
;	FrmPerBuff=1
;
; Then click the 'Iso Trans' button as many times as you wish.  The frame
; count and all 24 input port lines appear in the data window.
;-----------------------------------------------------------------
$NOMOD51		; disable predefined 8051 registers
$nolist
$include (..\..\..\target\inc\ezregs.inc)	; EZ-USB register assignments
$list
;
NAME	        eziso
;
		CSEG AT 0
        mov     dptr,#IN8ADDR   ; set the FIFO start for EP8 to 0
        mov     a,#0
        movx    @dptr,a
 		ljmp	loop
; -------------------------------------------------
		org	100h		
; -------------------------------------------------
loop:		mov	dptr,#USBIRQ	; wait for SOF IRQ bit
		movx	a,@dptr
 		jnb	acc.1,loop
;
		mov	a,#00000010b	; SOFIR bit 
		movx	@dptr,a		; writing 1 clears the SOF IRQ bit
;
		mov	dptr,#USBFRAMEH	; put the frame number into first two EP8IN bytes
 		movx	a,@dptr
  		mov	dptr,#IN8DATA	; "IN8DATA" is a FIFO inside the EZ-USB chip
   		movx	@dptr,a		; byte 0	
		mov	dptr,#USBFRAMEL
 		movx	a,@dptr
  		mov	dptr,#IN8DATA
   		movx	@dptr,a 	; byte 1
    		
  		mov	dptr,#PINSA	; read PORTA pins
   		movx	a,@dptr
    		mov	dptr,#IN8DATA
     		movx	@dptr,a		; byte 2
  		mov	dptr,#PINSB	; read PORTB pins
   		movx	a,@dptr
    		mov	dptr,#IN8DATA
     		movx	@dptr,a		; byte 3
  		mov	dptr,#PINSC	; read PORTC pins
   		movx	a,@dptr
    		mov	dptr,#IN8DATA
     		movx	@dptr,a		; byte 4
;
      		sjmp	loop
;
		END