benagricola · June 8, 2024 16:16 · benagricola · May 2, 2024 · benagricola · May 3, 2024
diff --git a/test.py b/test.py
 import array
 import math
 import time
 import os
 import usb.device

 from uac2 import AudioInterface

 print("Okay, configuring the audio interface now...")


 # Constants
 sample_rate = 48000
 frequency = 440  # 440Hz
 num_samples = 10  # number of samples to fit in 60 bytes

 # Generate the sine wave
 wave = [0.5 * math.sin(2 * math.pi * frequency * (i / sample_rate)) for i in range(num_samples)]

 # Convert to 24-bit PCM
 wave_pcm = [int(sample * (2**23 - 1)) for sample in wave]

 # Convert to bytes and interleave left and right channels (they are the same because it's mono)
 byte_array = bytearray()
 for sample in wave_pcm:
    # Convert sample to 24-bit little-endian
    sample_bytes = sample.to_bytes(3, 'little')
    # Add sample to left channel
    byte_array.extend(sample_bytes)
    # Add sample to right channel
    byte_array.extend(sample_bytes)

 print("Sample Len: {}".format(len(byte_array)))

 class AudioTest(AudioInterface):
    def __init__(self, sample):
        self.sample = sample
        super().__init__()

    def send_sample(self):
        self._tx.write(self.sample)


 # Create an AudioInterface instance

 print("Creating AudioTest instance...")
 # Replace 'AudioInterface' with your actual AudioInterface class
 m = AudioTest(sample=byte_array)

 print("Initializing USB device...")
 usb.device.get().init(m, builtin_driver=True)

 while not m.is_open():
    print("Waiting for USB host to configure the interface...")
    time.sleep_ms(100)

 print("USB host configured the interface")

 while m.is_open():
    m.send_sample()
    m._tx_xfer()


 print("Finished")
diff --git a/uac2.py b/uac2.py
 # MicroPython USB AUDIO INPUT module
 # MIT license; Copyright (c) 2023 Paul Hamshere, 2023-2024 Angus Gratton
 from micropython import const
 import struct, time

 from usb.device.core import Interface, Buffer

 _EP_IN_FLAG = const(1 << 7)

 _INTERFACE_CLASS_AUDIO = const(0x01)
 _INTERFACE_SUBCLASS_AUDIO_CONTROL = const(0x01)
 _INTERFACE_SUBCLASS_AUDIO_STREAMING = const(0x02)

 class AudioInterface(Interface):
    # Base class to implement a USB Audio input device in Python.

    def __init__(self, txlen=30):
        # Arguments are size of transmit and receive buffers in bytes.

        super().__init__()
        self.ep_in = None  # TX direction (device to host)
        self._tx = Buffer(txlen)

    def _tx_xfer(self):
        # Keep an active IN transfer to send data to the host, whenever
        # there is data to send.
        if self.is_open() and not self.xfer_pending(self.ep_in) and self._tx.readable():
            self.submit_xfer(self.ep_in, self._tx.pend_read(), self._tx_cb)

    def _tx_cb(self, ep, res, num_bytes):
        if res == 0:
           self._tx.finish_read(num_bytes)

    def desc_cfg(self, desc, itf_num, ep_num, strs):
        # By this point, standard device and configuration descriptors have been added.

        # Append the standard AudioControl interface descriptor
        desc.interface(itf_num, 0, _INTERFACE_CLASS_AUDIO, _INTERFACE_SUBCLASS_AUDIO_CONTROL)

        # Append the class-specific AC interface header descriptor
        desc.pack(
            "<BBBHHBB",
            9,  # bLength
            0x24,  # bDescriptorType CS_INTERFACE
            0x01,  # bDescriptorSubtype MS_HEADER
            0x0100,  # BcdADC
            0x0009,  # wTotalLength
            0x01,  # bInCollection,
            itf_num + 1,  # baInterfaceNr - points to the Audio Streaming interface
        )

        # Append the input terminal descriptor
        # Append input terminal name
        idx = len(strs)+1
        strs.append("MicroPython Audio Input")

        desc.pack(
            "<BBBBHBBHBB",
            12,    # bLength
            0x24,  # bDescriptorType CS_INTERFACE
            0x02,  # bDescriptorSubtype INPUT_TERMINAL
            0x01,  # bTerminalID
            0x0603,# wTerminalType - USB streaming
            0x00,  # bAssocTerminal - no association
            0x02,  # bNrChannels - 2 channels
            0x0003,  # wChannelConfig - left and right front speakers
            0x00,  # iChannelNames - no string
            idx,   # iTerminal - no string
        )

        # Next add the Audio Streaming interface descriptor
        desc.interface(
            itf_num + 1, 1, _INTERFACE_CLASS_AUDIO, _INTERFACE_SUBCLASS_AUDIO_STREAMING
        )

        # Append the class-specific AS interface descriptor
        desc.pack(
            "<BBBBBH",
            7,     # bLength
            0x24,  # bDescriptorType CS_INTERFACE
            0x01,  # bDescriptorSubtype AS_GENERAL
            0x01,  # bTerminalLink - points to the Terminal ID of the Terminal to which the endpoint of this interface is connected
            0x01,  # bDelay - delay introduced by the data path
            0x0001,# wFormatTag - PCM
        )

        # Append the Type I format type descriptor
        desc.pack(
            "<BBBBBBBB3B",
            11,    # bLength
            0x24,  # bDescriptorType CS_INTERFACE
            0x02,  # bDescriptorSubtype FORMAT_TYPE
            0x01,  # bFormatType - Type I
            2,     # bNrChannels - 2 channels
            3,     # bSubframeSize - 3 bytes per audio subframe
            24,    # bBitResolution - 24 bits per sample
            1,     # bSamFreqType - 1 discrete sampling frequencies
            0x80, 0xBB, 0x00,  # tSamFreq - 48000 Hz
        )

        self.ep_in = ep_num | _EP_IN_FLAG

        # # rx side, USB "in" endpoint
        _audio_endpoint(desc, self.ep_in)

    def num_itfs(self):
        return 2

    def num_eps(self):
        return 1

    def on_open(self):
        super().on_open()
        # kick off any transfers that may have queued while the device was not open
        self._tx_xfer()

 def _audio_endpoint(desc, bEndpointAddress):
    # Append the standard AS Isochronous Audio Data Endpoint descriptor
    desc.pack(
        "<BBBBHB",
        7,      # bLength
        0x05,   # bDescriptorType ENDPOINT
        bEndpointAddress,  # bEndpointAddress
        0x01,   # bmAttributes - Isochronous
        0x0120, # wMaxPacketSize
        0x01,   # bInterval
    )

    # Append the class-specific AS Isochronous Audio Data Endpoint descriptor
    desc.pack(
        "<BBBBBH",
        7,  # bLength
        0x25,  # bDescriptorType CS_ENDPOINT
        0x01,  # bDescriptorSubtype EP_GENERAL
        0x00,  # bmAttributes
        0x00,  # bLockDelayUnits
        0x0000,  # wLockDelay
    )
	import array
	import math
	import time
	import os
	import usb.device

	from uac2 import AudioInterface

	print("Okay, configuring the audio interface now...")


	# Constants
	sample_rate = 48000
	frequency = 440 # 440Hz
	num_samples = 10 # number of samples to fit in 60 bytes

	# Generate the sine wave
	wave = [0.5 * math.sin(2 * math.pi * frequency * (i / sample_rate)) for i in range(num_samples)]

	# Convert to 24-bit PCM
	wave_pcm = [int(sample * (2**23 - 1)) for sample in wave]

	# Convert to bytes and interleave left and right channels (they are the same because it's mono)
	byte_array = bytearray()
	for sample in wave_pcm:
	# Convert sample to 24-bit little-endian
	sample_bytes = sample.to_bytes(3, 'little')
	# Add sample to left channel
	byte_array.extend(sample_bytes)
	# Add sample to right channel
	byte_array.extend(sample_bytes)

	print("Sample Len: {}".format(len(byte_array)))

	class AudioTest(AudioInterface):
	def __init__(self, sample):
	self.sample = sample
	super().__init__()

	def send_sample(self):
	self._tx.write(self.sample)


	# Create an AudioInterface instance

	print("Creating AudioTest instance...")
	# Replace 'AudioInterface' with your actual AudioInterface class
	m = AudioTest(sample=byte_array)

	print("Initializing USB device...")
	usb.device.get().init(m, builtin_driver=True)

	while not m.is_open():
	print("Waiting for USB host to configure the interface...")
	time.sleep_ms(100)

	print("USB host configured the interface")

	while m.is_open():
	m.send_sample()
	m._tx_xfer()


	print("Finished")
	# MicroPython USB AUDIO INPUT module
	# MIT license; Copyright (c) 2023 Paul Hamshere, 2023-2024 Angus Gratton
	from micropython import const
	import struct, time

	from usb.device.core import Interface, Buffer

	_EP_IN_FLAG = const(1 << 7)

	_INTERFACE_CLASS_AUDIO = const(0x01)
	_INTERFACE_SUBCLASS_AUDIO_CONTROL = const(0x01)
	_INTERFACE_SUBCLASS_AUDIO_STREAMING = const(0x02)

	class AudioInterface(Interface):
	# Base class to implement a USB Audio input device in Python.

	def __init__(self, txlen=30):
	# Arguments are size of transmit and receive buffers in bytes.

	super().__init__()
	self.ep_in = None # TX direction (device to host)
	self._tx = Buffer(txlen)

	def _tx_xfer(self):
	# Keep an active IN transfer to send data to the host, whenever
	# there is data to send.
	if self.is_open() and not self.xfer_pending(self.ep_in) and self._tx.readable():
	self.submit_xfer(self.ep_in, self._tx.pend_read(), self._tx_cb)

	def _tx_cb(self, ep, res, num_bytes):
	if res == 0:
	self._tx.finish_read(num_bytes)

	def desc_cfg(self, desc, itf_num, ep_num, strs):
	# By this point, standard device and configuration descriptors have been added.

	# Append the standard AudioControl interface descriptor
	desc.interface(itf_num, 0, _INTERFACE_CLASS_AUDIO, _INTERFACE_SUBCLASS_AUDIO_CONTROL)

	# Append the class-specific AC interface header descriptor
	desc.pack(
	"<BBBHHBB",
	9, # bLength
	0x24, # bDescriptorType CS_INTERFACE
	0x01, # bDescriptorSubtype MS_HEADER
	0x0100, # BcdADC
	0x0009, # wTotalLength
	0x01, # bInCollection,
	itf_num + 1, # baInterfaceNr - points to the Audio Streaming interface
	)

	# Append the input terminal descriptor
	# Append input terminal name
	idx = len(strs)+1
	strs.append("MicroPython Audio Input")

	desc.pack(
	"<BBBBHBBHBB",
	12, # bLength
	0x24, # bDescriptorType CS_INTERFACE
	0x02, # bDescriptorSubtype INPUT_TERMINAL
	0x01, # bTerminalID
	0x0603,# wTerminalType - USB streaming
	0x00, # bAssocTerminal - no association
	0x02, # bNrChannels - 2 channels
	0x0003, # wChannelConfig - left and right front speakers
	0x00, # iChannelNames - no string
	idx, # iTerminal - no string
	)

	# Next add the Audio Streaming interface descriptor
	desc.interface(
	itf_num + 1, 1, _INTERFACE_CLASS_AUDIO, _INTERFACE_SUBCLASS_AUDIO_STREAMING
	)

	# Append the class-specific AS interface descriptor
	desc.pack(
	"<BBBBBH",
	7, # bLength
	0x24, # bDescriptorType CS_INTERFACE
	0x01, # bDescriptorSubtype AS_GENERAL
	0x01, # bTerminalLink - points to the Terminal ID of the Terminal to which the endpoint of this interface is connected
	0x01, # bDelay - delay introduced by the data path
	0x0001,# wFormatTag - PCM
	)

	# Append the Type I format type descriptor
	desc.pack(
	"<BBBBBBBB3B",
	11, # bLength
	0x24, # bDescriptorType CS_INTERFACE
	0x02, # bDescriptorSubtype FORMAT_TYPE
	0x01, # bFormatType - Type I
	2, # bNrChannels - 2 channels
	3, # bSubframeSize - 3 bytes per audio subframe
	24, # bBitResolution - 24 bits per sample
	1, # bSamFreqType - 1 discrete sampling frequencies
	0x80, 0xBB, 0x00, # tSamFreq - 48000 Hz
	)

	self.ep_in = ep_num \| _EP_IN_FLAG

	# # rx side, USB "in" endpoint
	_audio_endpoint(desc, self.ep_in)

	def num_itfs(self):
	return 2

	def num_eps(self):
	return 1

	def on_open(self):
	super().on_open()
	# kick off any transfers that may have queued while the device was not open
	self._tx_xfer()

	def _audio_endpoint(desc, bEndpointAddress):
	# Append the standard AS Isochronous Audio Data Endpoint descriptor
	desc.pack(
	"<BBBBHB",
	7, # bLength
	0x05, # bDescriptorType ENDPOINT
	bEndpointAddress, # bEndpointAddress
	0x01, # bmAttributes - Isochronous
	0x0120, # wMaxPacketSize
	0x01, # bInterval
	)

	# Append the class-specific AS Isochronous Audio Data Endpoint descriptor
	desc.pack(
	"<BBBBBH",
	7, # bLength
	0x25, # bDescriptorType CS_ENDPOINT
	0x01, # bDescriptorSubtype EP_GENERAL
	0x00, # bmAttributes
	0x00, # bLockDelayUnits
	0x0000, # wLockDelay
	)