' =========================================================================
'
'   File....... SW21-EX03-Counter_LEDs.BS2
'   Purpose.... Advanced LED Flasher
'   Author..... (C) 2000 - 2005, Parallax, Inc.
'   E-mail..... support@parallax.com
'   Started....
'   Updated.... 01 SEP 2005
'
'   {$STAMP BS2}
'   {$PBASIC 2.5}
'
' =========================================================================


' -----[ Program Description ]---------------------------------------------
'
' Displays a 4-bit binary counter on LEDs connected to P0 - P3.  This
' program will work, unmodified, on any BS2-family module.


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

LEDs            VAR     OUTA                    ' LEDs on P0 - P3
LEDsDirs        VAR     DIRA                    ' DIRS control for LEDs


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

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

DelayTm         CON     100                     ' delay time for LEDs


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

cntr            VAR     Nib                     ' 4-bit counter variable


' -----[ Initialization ]--------------------------------------------------

Reset:
  LEDsDirs = %1111                              ' make LEDs outputs


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

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