Merge pull request #5 from tannewt/pwm_support

Support PWM output.

Author: kattni

adafruit_rtttl.py

@@ -32,37 +32,76 @@
 __repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_RTTTL"
 
 import time
-from adafruit_waveform import sine
-import audioio
-
-PIANO = {"4a#": 466.16,
- "4b" : 493.88,
- "5c" : 523.25,
- "5c#": 554.37,
- "5d" : 587.33,
- "5d#": 622.25,
- "5e" : 659.26,
- "5f" : 698.46,
- "5f#": 739.99,
- "5g" : 783.99,
- "5g#": 830.61,
+import pulseio
+
+AUDIOIO_AVAILABLE = False
+try:
+ import audioio
+ from adafruit_waveform import sine
+ AUDIOIO_AVAILABLE = True
+except ImportError:
+ pass
+
+PIANO = {"4c" : 261.626,
+ "4c#": 277.183,
+ "4d" : 293.665,
+ "4d#": 311.127,
+ "4e" : 329.628,
+ "4f" : 349.228,
+ "4f#": 369.994,
+ "4g" : 391.995,
+ "4g#": 415.305,
+ "4a" : 440,
+ "4a#": 466.164,
+ "4b" : 493.883,
+ "5c" : 523.251,
+ "5c#": 554.365,
+ "5d" : 587.330,
+ "5d#": 622.254,
+ "5e" : 659.255,
+ "5f" : 698.456,
+ "5f#": 739.989,
+ "5g" : 783.991,
+ "5g#": 830.609,
  "5a" : 880,
- "5a#": 932.33,
- "5b" : 987.77,
- "6c" : 1046.5,
- "6c#": 1108.7,
- "6d" : 1174.7,
- "6d#": 1244.5,
- "6e" : 1318.5,
- "6f" : 1396.9,
- "6f#": 1480,
- "6g" : 1568,
- "6g#": 1661.2,
+ "5a#": 932.328,
+ "5b" : 987.767,
+ "6c" : 1046.50,
+ "6c#": 1108.73,
+ "6d" : 1174.66,
+ "6d#": 1244.51,
+ "6e" : 1318.51,
+ "6f" : 1396.91,
+ "6f#": 1479.98,
+ "6g" : 1567.98,
+ "6g#": 1661.22,
  "6a" : 1760,
- "6a#": 1864.7,
- "6b" : 1975.5,
+ "6a#": 1864.66,
+ "6b" : 1975.53,
  "7c" : 2093,
- "7c#": 2217.5}
+ "7c#": 2217.46}
+
+def _parse_note(note, duration=2, octave="6"):
+ note = note.strip()
+ piano_note = None
+ note_duration = duration
+ if note[0].isdigit() and note[1].isdigit():
+ note_duration = int(note[:2])
+ piano_note = note[2]
+ elif note[0].isdigit():
+ note_duration = int(note[0])
+ piano_note = note[1]
+ else:
+ piano_note = note[0]
+ if "." in note:
+ note_duration *= 1.5
+ if "#" in note:
+ piano_note += "#"
+ note_octave = octave
+ if note[-1].isdigit():
+ note_octave = note[-1]
+ piano_note = note_octave + piano_note
+ return piano_note, note_duration
 
 def _get_wave(tune, octave):
  """Returns the proper waveform to play the song along with the minimum
@@ -71,17 +110,7 @@ def _get_wave(tune, octave):
  min_freq = 13000
 
  for note in tune.split(","):
- piano_note = None
- if note[0].isdigit():
- piano_note = note[1]
- else:
- piano_note = note[0]
- if "#" in note:
- piano_note += "#"
- note_octave = octave
- if note[-1].isdigit():
- note_octave = note[-1]
- piano_note = note_octave + piano_note
+ piano_note, _ = _parse_note(note, octave=octave)
  if piano_note[-1] != "p" and PIANO[piano_note] < min_freq:
  min_freq = PIANO[piano_note]
  return sine.sine_wave(16000, min_freq), min_freq
@@ -91,28 +120,22 @@ def _get_wave(tune, octave):
 def _play_to_pin(tune, base_tone, min_freq, duration, octave, tempo):
  """Using the prepared input send the notes to the pin
  """
+ pwm = isinstance(base_tone, pulseio.PWMOut)
  for note in tune.split(","):
- piano_note = None
- note_duration = duration
- if note[0].isdigit():
- note_duration = int(note[0])
- piano_note = note[1]
- else:
- piano_note = note[0]
- if "." in note:
- note_duration *= 1.5
- if "#" in note:
- piano_note += "#"
- note_octave = octave
- if note[-1].isdigit():
- note_octave = note[-1]
- piano_note = note_octave + piano_note
+ piano_note, note_duration = _parse_note(note, duration, octave)
  if piano_note in PIANO:
- base_tone.frequency = int(16000 * (PIANO[piano_note] / min_freq))
- base_tone.play(loop=True)
+ if pwm:
+ base_tone.frequency = int(PIANO[piano_note])
+ base_tone.duty_cycle = 2 ** 15
+ else:
+ base_tone.frequency = int(16000 * (PIANO[piano_note] / min_freq))
+ base_tone.play(loop=True)
  print(piano_note, note_duration)
  time.sleep(4 / note_duration * 60 / tempo)
- base_tone.stop()
+ if pwm:
+ base_tone.duty_cycle = 0
+ else:
+ base_tone.stop()
  time.sleep(0.02)
 
 #pylint: disable-msg=too-many-arguments
@@ -124,7 +147,7 @@ def play(pin, rtttl, octave=None, duration=None, tempo=None):
  :param int duration: length of notes (default 4 quarter note)
  :param int tempo: how fast (default 63 beats per minute)
  """
- _, defaults, tune = rtttl.split(":")
+ _, defaults, tune = rtttl.lower().split(":")
  for default in defaults.split(","):
  if default[0] == "d" and not duration:
  duration = int(default[2:])
@@ -141,8 +164,18 @@ def play(pin, rtttl, octave=None, duration=None, tempo=None):
 
  print("tempo", tempo, "octave", octave, "duration", duration)
 
- wave, min_freq = _get_wave(tune, octave)
+ base_tone = None
+ min_freq = 440
+ if AUDIOIO_AVAILABLE:
+ wave, min_freq = _get_wave(tune, octave)
+ try:
+ base_tone = audioio.AudioOut(pin, wave)
+ except ValueError:
+ # No DAC on the pin so use PWM.
+ pass
 
- base_tone = audioio.AudioOut(pin, wave)
+ # Fall back to PWM
+ if not base_tone:
+ base_tone = pulseio.PWMOut(pin, duty_cycle=0, variable_frequency=True)
 
  _play_to_pin(tune, base_tone, min_freq, duration, octave, tempo)

docs/conf.py

@@ -15,7 +15,7 @@
  'sphinx.ext.viewcode',
 ]
 
-autodoc_mock_imports = ["audioio", "adafruit_waveform"]
+autodoc_mock_imports = ["audioio", "adafruit_waveform", "pulseio"]
 
 intersphinx_mapping = {'python': ('https://docs.python.org/3.4', None),'CircuitPython': ('https://circuitpython.readthedocs.io/en/latest/', None)}