Implement play_wav, record_voice, and host-side voice assistant coordinator script

audio_util.py

@@ -283,3 +283,117 @@ def play_tone(frequency=440, duration_ms=1000, volume=50):
     print("Tone playback complete.")
     return True
 
+
+def play_wav(filename, volume=50):
+    """Plays a standard WAV audio file on the board speaker.
+    
+    Standard format: 16-bit PCM, 16kHz sample rate (recommended).
+    """
+    import struct
+    
+    print(f"Playing WAV: {filename} (vol={volume})...")
+    
+    try:
+        f = open(filename, 'rb')
+    except OSError:
+        print(f"Error: Cannot open WAV file '{filename}'")
+        return False
+        
+    try:
+        # 1. Parse WAV header chunk by chunk
+        riff_header = f.read(12)
+        if len(riff_header) < 12 or riff_header[0:4] != b'RIFF' or riff_header[8:12] != b'WAVE':
+            print("Error: Invalid WAV file format")
+            f.close()
+            return False
+            
+        channels = 1
+        sample_rate = 16000
+        bits = 16
+        
+        while True:
+            chunk_header = f.read(8)
+            if len(chunk_header) < 8:
+                break
+            chunk_id, chunk_size = struct.unpack('<4sI', chunk_header)
+            
+            if chunk_id == b'fmt ':
+                fmt_data = f.read(chunk_size)
+                if len(fmt_data) >= 16:
+                    audio_format, channels, sample_rate, byte_rate, block_align, bits = struct.unpack('<HHIIHH', fmt_data[:16])
+                    if audio_format != 1:
+                        print(f"Warning: Non-PCM audio format ({audio_format})")
+                else:
+                    print("Error: fmt chunk too small")
+                    f.close()
+                    return False
+            elif chunk_id == b'data':
+                # Audio data begins immediately after this chunk size
+                break
+            else:
+                # Skip unknown chunk (align to even byte)
+                skip_bytes = (chunk_size + 1) & ~1
+                f.seek(skip_bytes, 1)
+                
+        print(f"WAV Info: {sample_rate}Hz, {bits} bits, {'Mono' if channels == 1 else 'Stereo'}")
+        
+        # 2. Setup Master Clock (MCLK) on GPIO 16 using PWM
+        mclk_pin = Pin(16, Pin.OUT)
+        mclk_pwm = machine.PWM(mclk_pin)
+        mclk_pwm.freq(12288000)
+        mclk_pwm.duty_u16(32768)
+        
+        # 3. Start I2C Control Bus (SDA=13, SCL=14)
+        i2c = I2C(0, sda=Pin(13), scl=Pin(14))
+        
+        # 4. Initialize the ES8311 DAC
+        dac = ES8311(i2c)
+        if not dac.init(sample_rate=16000):
+            mclk_pwm.deinit()
+            f.close()
+            return False
+            
+        dac.set_volume(volume)
+        
+        # 5. Configure I2S TX
+        # Pins: sck=BCLK (GPIO 9), ws=WS/LRCK (GPIO 45), sd=DOUT (GPIO 8)
+        i2s_format = I2S.MONO if channels == 1 else I2S.STEREO
+        i2s = I2S(1,
+                  sck=Pin(9),
+                  ws=Pin(45),
+                  sd=Pin(8),
+                  mode=I2S.TX,
+                  ibuf=4096,
+                  rate=sample_rate,
+                  bits=bits,
+                  format=i2s_format)
+                  
+        # 6. Enable Speaker Amplifier (GPIO 46)
+        amp_pin = Pin(46, Pin.OUT, value=1)
+        
+        # 7. Read and stream chunks to I2S
+        buf = bytearray(2048)
+        while True:
+            bytes_read = f.readinto(buf)
+            if bytes_read == 0:
+                break
+            i2s.write(buf[:bytes_read])
+            
+        # 8. Clean up
+        time.sleep_ms(100) # Let the remaining buffer play out
+        amp_pin.value(0)
+        i2s.deinit()
+        mclk_pwm.deinit()
+        f.close()
+        print("WAV playback complete.")
+        return True
+        
+    except Exception as e:
+        print(f"Error during WAV playback: {e}")
+        try:
+            f.close()
+        except:
+            pass
+        return False
+
+