*
* Ex2.asm  ---- Example program 2 for the Ep2711E9 Rev.C board
*		(c)2003, EVBplus.com, Written by Wayne Chu
*
*     Function:	Makes the port B as a binary counter.
*
* The 68HC11 control register address is the offset address from the
* register base address $1000, so index addressing mode can also be used,
* otherwise only extended addressing mode can be used.
*
*
        ORG  $c4
*** Vector jump table for BUFFALO monitor ***
JSCI    RMB   3
JSPI    RMB   3
JPAIE   RMB   3
JPAO    RMB   3
JTOF    RMB   3
JTOC5   RMB   3
JTOC4   RMB   3
JTOC3   RMB   3
JTOC2   RMB   3
JTOC1   RMB   3
JTIC3   RMB   3
JTIC2   RMB   3
JTIC1   RMB   3
JRTI    RMB   3
JIRQ    RMB   3
JXIRQ   RMB   3
JSWI    RMB   3
JILLOP  RMB   3
JCOP    RMB   3
JCLM    RMB   3
	
portb:		equ	$4
REGBLK:		equ	$1000
SPEED:          equ     $2500    ; change this number to change counting speed

STACK:	equ	$8FFF
*
	
	org	$D000		; user program starts at $D000
	
start:
	lds	#STACK
	ldx	#REGBLK
back:	inca
	staa 	portb,x
	jsr	delay
	jmp	back
*
delay:	pshx
	ldx	#SPEED		; delay 2500 loops =2000 cycles = 10ms
dly:	dex			; 3 cycles
	nop			; 2 cycle
	bne	dly		; 3 cycles
	pulx
	rts

*	
	end