:mod:`audiopwmio`
=================

.. py:module:: audiopwmio

.. autoapi-nested-parse::

   Audio output via digital PWM

   The `audiopwmio` module contains classes to provide access to audio IO.

   All classes change hardware state and should be deinitialized when they
   are no longer needed if the program continues after use. To do so, either
   call :py:meth:`!deinit` or use a context manager. See
   :ref:`lifetime-and-contextmanagers` for more info.

   Since CircuitPython 5, `Mixer`, `RawSample` and `WaveFile` are moved
   to :mod:`audiocore`.



.. raw:: html

    <p>
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    </details>
    </p>




.. py:class:: PWMAudioOut(left_channel: microcontroller.Pin, *, right_channel: Optional[microcontroller.Pin] = None, quiescent_value: int = 32768)

   Output an analog audio signal by varying the PWM duty cycle.

   Create a PWMAudioOut object associated with the given pin(s). This allows you to
   play audio signals out on the given pin(s).  In contrast to mod:`audioio`,
   the pin(s) specified are digital pins, and are driven with a device-dependent PWM
   signal.

   :param ~microcontroller.Pin left_channel: The pin to output the left channel to
   :param ~microcontroller.Pin right_channel: The pin to output the right channel to
   :param int quiescent_value: The output value when no signal is present. Samples should start
       and end with this value to prevent audible popping.

   Simple 8ksps 440 Hz sin wave::

     import audiocore
     import audiopwmio
     import board
     import array
     import time
     import math

     # Generate one period of sine wav.
     length = 8000 // 440
     sine_wave = array.array("H", [0] * length)
     for i in range(length):
         sine_wave[i] = int(math.sin(math.pi * 2 * i / length) * (2 ** 15) + 2 ** 15)

     dac = audiopwmio.PWMAudioOut(board.SPEAKER)
     sine_wave = audiocore.RawSample(sine_wave, sample_rate=8000)
     dac.play(sine_wave, loop=True)
     time.sleep(1)
     dac.stop()

   Playing a wave file from flash::

     import board
     import audiocore
     import audiopwmio
     import digitalio

     # Required for CircuitPlayground Express
     speaker_enable = digitalio.DigitalInOut(board.SPEAKER_ENABLE)
     speaker_enable.switch_to_output(value=True)

     data = open("cplay-5.1-16bit-16khz.wav", "rb")
     wav = audiocore.WaveFile(data)
     a = audiopwmio.PWMAudioOut(board.SPEAKER)

     print("playing")
     a.play(wav)
     while a.playing:
       pass
     print("stopped")

   .. py:attribute:: playing
      :annotation: :bool

      True when an audio sample is being output even if `paused`. (read-only)


   .. py:attribute:: paused
      :annotation: :bool

      True when playback is paused. (read-only)


   .. py:method:: deinit() -> None

      Deinitialises the PWMAudioOut and releases any hardware resources for reuse.


   .. py:method:: __enter__() -> PWMAudioOut

      No-op used by Context Managers.


   .. py:method:: __exit__() -> None

      Automatically deinitializes the hardware when exiting a context. See
      :ref:`lifetime-and-contextmanagers` for more info.


   .. py:method:: play(sample: _typing.AudioSample, *, loop: bool = False) -> None

      Plays the sample once when loop=False and continuously when loop=True.
      Does not block. Use `playing` to block.

      Sample must be an `audiocore.WaveFile`, `audiocore.RawSample`, `audiomixer.Mixer` or `audiomp3.MP3Decoder`.

      The sample itself should consist of 16 bit samples. Microcontrollers with a lower output
      resolution will use the highest order bits to output.


   .. py:method:: stop() -> None

      Stops playback and resets to the start of the sample.


   .. py:method:: pause() -> None

      Stops playback temporarily while remembering the position. Use `resume` to resume playback.


   .. py:method:: resume() -> None

      Resumes sample playback after :py:func:`pause`.