*
* bled.asm  ---- Example program for the Ep2711E9 Rev. C board
*               (c)2003, EVBplus.com
*
*     Function:	It makes PB7 blink
*
*
*
PORTB:	equ	$4		; portB offset
REGBASE	equ	$1000

stack:	equ	$FF
*
        org     $9000
main:
	ldx	#$7a12		; load reg. X with the counting value for the 
				; off cycle ($7A12)
	ldy 	#$f424		; load reg. Y with the counting value on cycle 
*
loop	ldaa	#$7f		; OFF LOOP:
	anda	PORTB+REGBASE	; A (01111111) is "anded" with the pattern 
				; currently hold in PORTB. The result is 
				; put in A. In this way we affect only the 
				; pin 7 of PORTB.
	staa	PORTB+REGBASE
	nop			; delay (nop takes 2 cycles)
	nop			
	nop
	nop
	nop
	nop
	nop
	nop
	dex			; decrement reg. X (3 cycles)
	bne	loop		; branch on not equal to Zero (3 cycles)
*
	ldx	#$7A12		; reload the counter value to reg. X (7A12)
*
loop2	ldaa	#$80		; ON LOOP: 
	oraa	PORTB+REGBASE	; complement bit 7 of PORTB
	staa	PORTB+REGBASE
	nop			; delay (nop takes 2 cycles)
	nop
	nop
	nop
	nop
	nop
	nop
	dey			; decrement reg. Y (4 cycles)
	bne	loop2		; branch on not equal to Z (3 cycles)
*
	ldy     #$f424		;reload the counter value to reg. Y ($f424)
*	
        bra	loop		;the loop will continue forever
        

	org	$FFFE           ; reset vector
	fdb	main            ; start of the program (text)
	end