Merge pull request #1827 from kattni/pico-i2s-mp3

Adding Pico I2S code.

Author: kattni

MP3_Playback_RP2040/Pico_I2S_MP3/code.py

@@ -0,0 +1,17 @@
+"""
+CircuitPython I2S MP3 playback example.
+Plays a single MP3 once.
+"""
+import board
+import audiomp3
+import audiobusio
+
+audio = audiobusio.I2SOut(board.GP0, board.GP1, board.GP2)
+
+mp3 = audiomp3.MP3Decoder(open("slow.mp3", "rb"))
+
+audio.play(mp3)
+while audio.playing:
+    pass
+
+print("Done playing!")

MP3_Playback_RP2040/Pico_I2S_MP3/slow.mp3

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+"""
+CircuitPython I2S Tone playback example.
+Plays a tone for one second on, one
+second off, in a loop.
+"""
+import time
+import array
+import math
+import audiocore
+import board
+import audiobusio
+
+audio = audiobusio.I2SOut(board.GP0, board.GP1, board.GP2)
+
+tone_volume = 0.1  # Increase this to increase the volume of the tone.
+frequency = 440  # Set this to the Hz of the tone you want to generate.
+length = 8000 // frequency
+sine_wave = array.array("h", [0] * length)
+for i in range(length):
+    sine_wave[i] = int((math.sin(math.pi * 2 * i / length)) * tone_volume * (2 ** 15 - 1))
+sine_wave_sample = audiocore.RawSample(sine_wave)
+
+while True:
+    audio.play(sine_wave_sample, loop=True)
+    time.sleep(1)
+    audio.stop()
+    time.sleep(1)

MP3_Playback_RP2040/Pico_I2S_Tone/code.py

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+"""
+CircuitPython I2S WAV file playback.
+Plays a WAV file for six seconds, pauses
+for two seconds, then resumes and plays
+the file to the end.
+"""
+import time
+import audiocore
+import board
+import audiobusio
+
+audio = audiobusio.I2SOut(board.GP0, board.GP1, board.GP2)
+
+wave_file = open("StreetChicken.wav", "rb")
+wav = audiocore.WaveFile(wave_file)
+
+print("Playing wav file!")
+audio.play(wav)
+t = time.monotonic()
+while time.monotonic() - t < 6:
+    pass
+
+print("Pausing!")
+audio.pause()
+time.sleep(2)
+print("Resuming!")
+audio.resume()
+while audio.playing:
+    pass
+print("Done!")