' =========================================================================
'   File....... SSW21-EX03-Counter_LEDs.SXB
'   Purpose.... Advanced LED Flasher
'   Author..... (C) 2000 - 2005, Parallax, Inc.
'   E-mail..... support@parallax.com
'   Started.... 01 SEP 2005
'   Updated.... 23 MAR 2007 by TSaavik for SX28
' =========================================================================
' -----[ Program Description ]---------------------------------------------
'
' Displays a 4-bit binary counter on LEDs connected to RB.0 - RB.3.  This
' program will work, unmodified, on the SX28.

'------{ Device Settings ]-------------------------------------------------

DEVICE 		SX28,TURBO,BANKS8,OSCHS3,SYNC,OPTIONX
FREQ            50_000_000
ID		"EX03"

' -----[ I/O Definitions ]-------------------------------------------------

LEDs            VAR     RB			' LEDs on RB.0 - RB.3

' -----[ Constants ]-------------------------------------------------------

MinCount        CON     0                       ' counter start value
MaxCount        CON     15                      ' counter end value

'DelayTm         CON     100			' delay time for LEDs
DelayTm         CON     1			' delay time for LEDs in SXSIM

' -----[ Variables ]-------------------------------------------------------

cntr            VAR     Byte                 	' 4-bit counter variable, but not really

' -----[ Initialization ]-------------------------------------------------
PROGRAM Start

watch cntr
watch RB,8,ubin

' -----[ Program Code ]----------------------------------------------------

Start:
  TRIS_B = %11110000  
Main:
  DO
    FOR cntr = MinCount TO MaxCount             ' loop through all values
      LEDs = cntr                               ' move count to LEDs
      PAUSE DelayTm                             ' hold a bit
    break
    NEXT
  LOOP                                          ' repeat forever