$regfile = "attiny2313.dat"                                 ' the used chip
$crystal = 1000000                                          ' frequency used
$hwstack = 40
$swstack = 0
$framesize = 24
$baud = 38400

Config Portd = &B0000_1100 : Portd = 255                    'D2 &D3
 Sw Alias Pinb.0 : Portb = 255


Dim Period As Word , Adc_val As Word
Dim On_off As Byte , Sound_on As Byte , Sound_time As Byte , Idle_time As Byte
Dim T0_ticks As Byte , 100ms As Byte

Config Timer0 = Timer , Prescale = 1024 , Compare_a = Disconnect , Compare_b = Disconnect , Clear_timer = 1
 Compare0a = 96                                             '100ms @1MHz/1024
  On Compare0a Timer0_isr
   Enable Compare0a


 Set Acsr.acd                                               'disable AD
 Stop Watchdog

 Enable Interrupts

Do

 If 100ms = 0 Then
  100ms = 9
     If Idle_time = 0 Then                                  'we reboot or its time
      Sound_on = 1                                          'sound will be played
      T0_ticks = 0                                          'reset time counter to be compared
      Do                                                    'draw new time for pause
       Idle_time = Rnd(99)                                  '99 maximum
      Loop Until Idle_time > 9                              '9  minimum

     Else
      Decr Idle_time                                        'countdown
     End If
 End If

 Do                                                         'draw freq everytime for better randomness
  Period = Rnd(60)
 Loop Until Period > 3

 Do
  Sound_time = Rnd(30)                                      'draw period for sound
 Loop Until Sound_time > 15


 '-------[PLAYING HERE]--- (24mA)
 While Sound_on = 1                                         'this flag will be cleared in ISR
  Portd = &B0000_1000
  Waitus Period
  Portd = &B0000_0100
  Waitus Period
 Wend
 '------------------------
 Portd = 255                                                'playing end

 Config Powermode = Idle                                    'go to sleep (~9uA)

Loop
End

'ISR is needed to jump from While-Wend to measure time
Timer0_isr:                                                 '100ms
  If Sound_on = 1 Then
    Incr T0_ticks
    If T0_ticks = Sound_time Then                           'compare with drawn time
     Sound_on = 0

    End If
  Else
     If 100ms > 0 Then Decr 100ms
  End If
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