pwm.py

# Hardware PWM
MS_DISABLE = const(0)
MS_ENABLE  = const(1)

MODE_PWM        = const(0)
MODE_SERIALIZER = const(1)

DEFAULT_RANGE = const(960)

class PWM:
  def __init__(self, id, pin=-1, active=1, ms=MS_ENABLE, mode=MODE_PWM, polarity=0, silence=0, use_fifo=0, fifo_repeat=0):
    self._active = active
    self._flags = ms <<7 | use_fifo <<5 | polarity <<4 | silence <<3 |\
                  fifo_repeat <<2 | mode <<1
    if pin > 0:
      id_enabled = select_PWM_pin(pin)
      if id != id_enabled:
        raise ValueError
      else:
        self.id = id_enabled
    elif id == 0 or id == 1:
      self.id = id
    else:
      raise ValueError
    self.set_PWM_CTL(self.id, self._flags | active)
    # default settings: 1KHz output (19.2MHz / 960) / 20
    PWM_clock_config(CLK_OSC, 20)
    self.range(960)
      
  def PWM_CTL(self):
    return mem32[0x2020c000]

  def set_PWM_CTL(self, id, reg):
    mask = ~(0xff << id * 8)
    mem32[0x2020c000] = (mem32[0x2020c000] & mask) | reg << id * 8
  
  def range(self, rng=-1):
    if rng == -1:
      return mem32[0x2020c010 + 0x10 * self.id]
    else:
      save = self._active
      self.active(0)
      mem32[0x2020c010 + 0x10 * self.id] = rng
      self.active(save)
    
  def data(self, data=-1):
    if data == -1:
      return mem32[0x2020c014 + 0x10 * self.id]
    else:
      mem32[0x2020c014 + 0x10 * self.id] = data
  
  def active(self, bool=-1):
    if bool == -1:
      return (self.PWM_CTL() & 1 << 8 * self.id) > 0
    elif bool == 0 or bool == 1:
      self._active = bool
      self.set_PWM_CTL(self.id, self._flags | bool)
    else:
      raise ValueError 
  
  def duty(self, duty=-1):
    self.range(DEFAULT_RANGE)
    if duty == -1:
      return self.data(-1)
    self.data(duty)
  
  def freq(self, freq=-1):
    divi = (19200000 // DEFAULT_RANGE) // freq
    divf = round((((19200000 // DEFAULT_RANGE) / freq) - divi) * 4096)
    PWM_clock_config(CLK_OSC, divi, divf)