' =========================================================================
'
'   File....... Candles.BS2
'   Purpose.... Light faux candles (with LED wicks)
'   Author..... Parallax Team EFX
'   E-mail..... teamefx@parallax.com
'   Started....
'   Updated.... 28 SEP 2005
'
'   {$STAMP BS2}
'   {$PBASIC 2.5}
'
' =========================================================================


' -----[ Program Description ]---------------------------------------------
'
' This program controls six faux candles.  Each candle "flame" is comprised
' of three LEDs, a resistor, and a capacitor.  The capacitor allows the
' flame to fade when the BASIC Stamp output goes off, creating a more
' realistic effect.


' -----[ Revision History ]------------------------------------------------


' -----[ I/O Definitions ]-------------------------------------------------

Candles         VAR     OUTL                    ' candle outputs, P0-P5


' -----[ Constants ]-------------------------------------------------------

FlickBase       CON     10                      ' flicker base timing


' -----[ Variables ]-------------------------------------------------------

flicker         VAR     Word                    ' random flicker value
flickVar        VAR     flicker.BYTE1           ' affects flicker rate
wicks           VAR     Byte                    ' to test for dark
rate            VAR     Byte                    ' flicker rate


' -----[ EEPROM Data ]-----------------------------------------------------


' -----[ Initialization ]--------------------------------------------------

Reset:
  DIRL = %00111111                              ' make P0 - P5 outputs


' -----[ Program Code ]----------------------------------------------------

Main:
  RANDOM flicker                                ' tumble random generator

Check_Dark:
  wicks = flicker & %00111111                   ' test value
  IF wicks = %000000 THEN Main                  ' if dark, try again

Flame_On:
  Candles = wicks                               ' update outputs
  rate = flickVar & %00001111 + FlickBase       ' isolate lower 4 bits
  PAUSE rate                                    ' hold flames
  GOTO Main                                     ' start again


' -----[ Subroutines ]----------------------------------------------------- 