Commit before sharing.

Setup a test example - UNTESTED!
Missing: Start transmitting audio data in set_interface.

8 files changed, 1431 insertions, 810 deletions

diff --git a/examples/device/audio_test/Makefile b/examples/device/audio_test/Makefile
new file mode 100644
index 000000000..5a455078e
--- /dev/null
+++ b/examples/device/audio_test/Makefile
@@ -0,0 +1,12 @@
+include ../../../tools/top.mk
+include ../../make.mk
+
+INC += \
+  src \
+  $(TOP)/hw \
+
+# Example source
+EXAMPLE_SOURCE += $(wildcard src/*.c)
+SRC_C += $(addprefix $(CURRENT_PATH)/, $(EXAMPLE_SOURCE))
+
+include ../../rules.mk
diff --git a/examples/device/audio_test/src/main.c b/examples/device/audio_test/src/main.c
new file mode 100644
index 000000000..e55c64c7c
--- /dev/null
+++ b/examples/device/audio_test/src/main.c
@@ -0,0 +1,367 @@
+/* 
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Reinhard Panhuber
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "bsp/board.h"
+#include "tusb.h"
+
+//--------------------------------------------------------------------+
+// MACRO CONSTANT TYPEDEF PROTYPES
+//--------------------------------------------------------------------+
+
+/* Blink pattern
+ * - 250 ms  : device not mounted
+ * - 1000 ms : device mounted
+ * - 2500 ms : device is suspended
+ */
+enum  {
+  BLINK_NOT_MOUNTED = 250,
+  BLINK_MOUNTED = 1000,
+  BLINK_SUSPENDED = 2500,
+};
+
+static uint32_t blink_interval_ms = BLINK_NOT_MOUNTED;
+
+// Audio controls
+// Current states
+bool mute[CFG_TUD_AUDIO_N_CHANNELS_TX + 1]; 						// +1 for master channel 0
+uint16_t volume[CFG_TUD_AUDIO_N_CHANNELS_TX + 1]; 					// +1 for master channel 0
+uint32_t sampFreq;
+uint8_t clkValid;
+
+// Range states
+audio_control_range_2_n_t(1) volumeRng[CFG_TUD_AUDIO_N_CHANNELS_TX+1]; 			// Volume range state
+audio_control_range_4_n_t(1) sampleFreqRng; 						// Sample frequency range state
+
+void led_blinking_task(void);
+void audio_task(void);
+
+/*------------- MAIN -------------*/
+int main(void)
+{
+  board_init();
+
+  tusb_init();
+
+  // Init values
+  sampFreq = 44100;
+  clkValid = 1;
+
+  sampleFreqRng.wNumSubRanges = 1;
+  sampleFreqRng.subrange[0].bMin = 44100;
+  sampleFreqRng.subrange[0].bMax = 44100;
+  sampleFreqRng.subrange[0].bRes = 0;
+
+  while (1)
+  {
+    tud_task(); // tinyusb device task
+    led_blinking_task();
+    audio_task();
+  }
+
+
+  return 0;
+}
+
+//--------------------------------------------------------------------+
+// Device callbacks
+//--------------------------------------------------------------------+
+
+// Invoked when device is mounted
+void tud_mount_cb(void)
+{
+  blink_interval_ms = BLINK_MOUNTED;
+}
+
+// Invoked when device is unmounted
+void tud_umount_cb(void)
+{
+  blink_interval_ms = BLINK_NOT_MOUNTED;
+}
+
+// Invoked when usb bus is suspended
+// remote_wakeup_en : if host allow us  to perform remote wakeup
+// Within 7ms, device must draw an average of current less than 2.5 mA from bus
+void tud_suspend_cb(bool remote_wakeup_en)
+{
+  (void) remote_wakeup_en;
+  blink_interval_ms = BLINK_SUSPENDED;
+}
+
+// Invoked when usb bus is resumed
+void tud_resume_cb(void)
+{
+  blink_interval_ms = BLINK_MOUNTED;
+}
+
+//--------------------------------------------------------------------+
+// AUDIO Task
+//--------------------------------------------------------------------+
+
+void audio_task(void)
+{
+  // Yet to be filled - e.g. put meas data into TX FIFOs etc.
+  asm("nop");
+}
+
+//--------------------------------------------------------------------+
+// Application Callback API Implementations
+//--------------------------------------------------------------------+
+
+// Invoked when audio class specific set request received for an EP
+bool tud_audio_set_req_ep_cb(uint8_t rhport, tusb_control_request_t const * p_request, uint8_t *pBuff)
+{
+  (void) rhport;
+
+  // We do not support any set range requests here, only current value requests
+  TU_VERIFY(p_request->bRequest == AUDIO_CS_REQ_CUR);
+
+  // Page 91 in UAC2 specification
+  uint8_t channelNum = TU_U16_LOW(p_request->wValue);
+  uint8_t ctrlSel = TU_U16_HIGH(p_request->wValue);
+  uint8_t ep = TU_U16_LOW(p_request->wIndex);
+
+  return false; 	// Yet not implemented
+}
+
+// Invoked when audio class specific set request received for an interface
+bool tud_audio_set_req_itf_cb(uint8_t rhport, tusb_control_request_t const * p_request, uint8_t *pBuff)
+{
+  (void) rhport;
+
+  // We do not support any set range requests here, only current value requests
+  TU_VERIFY(p_request->bRequest == AUDIO_CS_REQ_CUR);
+
+  // Page 91 in UAC2 specification
+  uint8_t channelNum = TU_U16_LOW(p_request->wValue);
+  uint8_t ctrlSel = TU_U16_HIGH(p_request->wValue);
+  uint8_t itf = TU_U16_LOW(p_request->wIndex);
+
+  return false; 	// Yet not implemented
+}
+
+// Invoked when audio class specific set request received for an entity
+bool tud_audio_set_req_entity_cb(uint8_t rhport, tusb_control_request_t const * p_request, uint8_t *pBuff)
+{
+  (void) rhport;
+
+  // Page 91 in UAC2 specification
+  uint8_t channelNum = TU_U16_LOW(p_request->wValue);
+  uint8_t ctrlSel = TU_U16_HIGH(p_request->wValue);
+  uint8_t itf = TU_U16_LOW(p_request->wIndex);
+  uint8_t entityID = TU_U16_HIGH(p_request->wIndex);
+
+  // We do not support any set range requests here, only current value requests
+  TU_VERIFY(p_request->bRequest == AUDIO_CS_REQ_CUR);
+
+  // If request is for our feature unit
+  if (entityID == 2)
+  {
+    switch (ctrlSel)
+    {
+      case AUDIO_FU_CTRL_MUTE:
+	// Request uses format layout 1
+	TU_VERIFY(p_request->wLength == sizeof(audio_control_cur_1_t));
+
+	mute[channelNum] = ((audio_control_cur_1_t *)pBuff)->bCur;
+
+	TU_LOG2("    Set Mute: %d of channel: %u\r\n", mute[channelNum], channelNum);
+
+	return true;
+
+      case AUDIO_FU_CTRL_VOLUME:
+	// Request uses format layout 2
+	TU_VERIFY(p_request->wLength == sizeof(audio_control_cur_2_t));
+
+	volume[channelNum] = ((audio_control_cur_2_t *)pBuff)->bCur;
+
+	TU_LOG2("    Set Volume: %d dB of channel: %u\r\n", volume[channelNum], channelNum);
+
+	return true;
+
+	// Unknown/Unsupported control
+      default: TU_BREAKPOINT(); return false;
+    }
+  }
+  return false; 	// Yet not implemented
+}
+
+// Invoked when audio class specific get request received for an EP
+bool tud_audio_get_req_ep_cb(uint8_t rhport, tusb_control_request_t const * p_request)
+{
+  (void) rhport;
+
+  // Page 91 in UAC2 specification
+  uint8_t channelNum = TU_U16_LOW(p_request->wValue);
+  uint8_t ctrlSel = TU_U16_HIGH(p_request->wValue);
+  uint8_t ep = TU_U16_LOW(p_request->wIndex);
+
+  //	return tud_control_xfer(rhport, p_request, &tmp, 1);
+
+  return false; 	// Yet not implemented
+}
+
+// Invoked when audio class specific get request received for an interface
+bool tud_audio_get_req_itf_cb(uint8_t rhport, tusb_control_request_t const * p_request)
+{
+  (void) rhport;
+
+  // Page 91 in UAC2 specification
+  uint8_t channelNum = TU_U16_LOW(p_request->wValue);
+  uint8_t ctrlSel = TU_U16_HIGH(p_request->wValue);
+  uint8_t itf = TU_U16_LOW(p_request->wIndex);
+
+  return false; 	// Yet not implemented
+}
+
+// Invoked when audio class specific get request received for an entity
+bool tud_audio_get_req_entity_cb(uint8_t rhport, tusb_control_request_t const * p_request)
+{
+  (void) rhport;
+
+  // Page 91 in UAC2 specification
+  uint8_t channelNum = TU_U16_LOW(p_request->wValue);
+  uint8_t ctrlSel = TU_U16_HIGH(p_request->wValue);
+  // uint8_t itf = TU_U16_LOW(p_request->wIndex); 			// Since we have only one audio function implemented, we do not need the itf value
+  uint8_t entityID = TU_U16_HIGH(p_request->wIndex);
+
+  // Input terminal (Microphone input)
+  if (entityID == 1)
+  {
+    switch (ctrlSel)
+    {
+      case AUDIO_TE_CTRL_CONNECTOR:;
+      // The terminal connector control only has a get request with only the CUR attribute.
+
+      audio_desc_channel_cluster_t ret;
+
+      // Those are dummy values for now
+      ret.bNrChannels = 1;
+      ret.bmChannelConfig = 0;
+      ret.iChannelNames = 0;
+
+      TU_LOG2("    Get terminal connector\r\n");
+
+      return tud_audio_buffer_and_schedule_control_xfer(rhport, p_request, (void*)&ret, sizeof(ret));
+
+      // Unknown/Unsupported control selector
+      default: TU_BREAKPOINT(); return false;
+    }
+  }
+
+  // Feature unit
+  if (entityID == 2)
+  {
+    switch (ctrlSel)
+    {
+      case AUDIO_FU_CTRL_MUTE:
+	// Audio control mute cur parameter block consists of only one byte - we thus can send it right away
+	// There does not exist a range parameter block for mute
+	TU_LOG2("    Get Mute of channel: %u\r\n", channelNum);
+	return tud_control_xfer(rhport, p_request, &mute[channelNum], 1);
+
+      case AUDIO_FU_CTRL_VOLUME:
+
+	switch (p_request->bRequest)
+	{
+	  case AUDIO_CS_REQ_CUR:
+	    TU_LOG2("    Get Volume of channel: %u\r\n", channelNum);
+	    return tud_control_xfer(rhport, p_request, &volume[channelNum], sizeof(volume[channelNum]));
+	  case AUDIO_CS_REQ_RANGE:
+	    TU_LOG2("    Get Volume range of channel: %u\r\n", channelNum);
+
+	    // Copy values - only for testing - better is version below
+	    audio_control_range_2_n_t(1) ret;
+
+	    ret.wNumSubRanges = 1;
+	    ret.subrange[0].bMin = -90; 	// -90 dB
+	    ret.subrange[0].bMax = 90;		// +90 dB
+	    ret.subrange[0].bRes = 1; 		// 1 dB steps
+
+	    return tud_audio_buffer_and_schedule_control_xfer(rhport, p_request, (void*)&ret, sizeof(ret));
+
+	    // Unknown/Unsupported control
+	  default: TU_BREAKPOINT(); return false;
+	}
+
+	// Unknown/Unsupported control
+	  default: TU_BREAKPOINT(); return false;
+    }
+  }
+
+  // Clock Source unit
+  if (entityID == 4)
+  {
+    switch (ctrlSel)
+    {
+      case AUDIO_CS_CTRL_SAM_FREQ:
+
+	// channelNum is always zero in this case
+
+	switch (p_request->bRequest)
+	{
+	  case AUDIO_CS_REQ_CUR:
+	    TU_LOG2("    Get Sample Freq.\r\n");
+	    return tud_control_xfer(rhport, p_request, &sampFreq, sizeof(sampFreq));
+	  case AUDIO_CS_REQ_RANGE:
+	    TU_LOG2("    Get Sample Freq. range\r\n");
+	    return tud_control_xfer(rhport, p_request, &sampleFreqRng, sizeof(sampleFreqRng));
+
+	    // Unknown/Unsupported control
+	  default: TU_BREAKPOINT(); return false;
+	}
+
+	  case AUDIO_CS_CTRL_CLK_VALID:
+	    // Only cur attribute exists for this request
+	    TU_LOG2("    Get Sample Freq. valid\r\n");
+	    return tud_control_xfer(rhport, p_request, &clkValid, sizeof(clkValid));
+
+	    // Unknown/Unsupported control
+	  default: TU_BREAKPOINT(); return false;
+    }
+  }
+
+  TU_LOG2("  Unsupported entity: %d\r\n", entityID);
+  return false; 	// Yet not implemented
+}
+
+//--------------------------------------------------------------------+
+// BLINKING TASK
+//--------------------------------------------------------------------+
+void led_blinking_task(void)
+{
+  static uint32_t start_ms = 0;
+  static bool led_state = false;
+
+  // Blink every interval ms
+  if ( board_millis() - start_ms < blink_interval_ms) return; // not enough time
+  start_ms += blink_interval_ms;
+
+  board_led_write(led_state);
+  led_state = 1 - led_state; // toggle
+}
diff --git a/examples/device/audio_test/src/tusb_config.h b/examples/device/audio_test/src/tusb_config.h
new file mode 100644
index 000000000..6cd6882bc
--- /dev/null
+++ b/examples/device/audio_test/src/tusb_config.h
@@ -0,0 +1,112 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2019 Ha Thach (tinyusb.org)
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ */
+
+#ifndef _TUSB_CONFIG_H_
+#define _TUSB_CONFIG_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+//--------------------------------------------------------------------
+// COMMON CONFIGURATION
+//--------------------------------------------------------------------
+
+// defined by compiler flags for flexibility
+#ifndef CFG_TUSB_MCU
+#error CFG_TUSB_MCU must be defined
+#endif
+
+#if CFG_TUSB_MCU == OPT_MCU_LPC43XX || CFG_TUSB_MCU == OPT_MCU_LPC18XX || CFG_TUSB_MCU == OPT_MCU_MIMXRT10XX
+#define CFG_TUSB_RHPORT0_MODE       (OPT_MODE_DEVICE | OPT_MODE_HIGH_SPEED)
+#else
+#define CFG_TUSB_RHPORT0_MODE       OPT_MODE_DEVICE
+#endif
+
+#define CFG_TUSB_OS                 OPT_OS_NONE
+
+// CFG_TUSB_DEBUG is defined by compiler in DEBUG build
+// #define CFG_TUSB_DEBUG           0
+
+/* USB DMA on some MCUs can only access a specific SRAM region with restriction on alignment.
+ * Tinyusb use follows macros to declare transferring memory so that they can be put
+ * into those specific section.
+ * e.g
+ * - CFG_TUSB_MEM SECTION : __attribute__ (( section(".usb_ram") ))
+ * - CFG_TUSB_MEM_ALIGN   : __attribute__ ((aligned(4)))
+ */
+#ifndef CFG_TUSB_MEM_SECTION
+#define CFG_TUSB_MEM_SECTION
+#endif
+
+#ifndef CFG_TUSB_MEM_ALIGN
+#define CFG_TUSB_MEM_ALIGN          __attribute__ ((aligned(4)))
+#endif
+
+//--------------------------------------------------------------------
+// DEVICE CONFIGURATION
+//--------------------------------------------------------------------
+
+#ifndef CFG_TUD_ENDPOINT0_SIZE
+#define CFG_TUD_ENDPOINT0_SIZE    64
+#endif
+
+//------------- CLASS -------------//
+#define CFG_TUD_CDC               0
+#define CFG_TUD_MSC               0
+#define CFG_TUD_HID               0
+#define CFG_TUD_MIDI              0
+#define CFG_TUD_AUDIO             1
+#define CFG_TUD_VENDOR            0
+
+//--------------------------------------------------------------------
+// AUDIO CLASS DRIVER CONFIGURATION
+//--------------------------------------------------------------------
+
+// Audio format type
+#define CFG_TUD_AUDIO_USE_TX_FIFO 				1
+#define CFG_TUD_AUDIO_FORMAT_TYPE_TX 				AUDIO_FORMAT_TYPE_I
+#define CFG_TUD_AUDIO_FORMAT_TYPE_RX 				AUDIO_FORMAT_TYPE_UNDEFINED
+
+// Audio format type I specifications
+#define CFG_TUD_AUDIO_FORMAT_TYPE_I_TX 				AUDIO_DATA_FORMAT_TYPE_I_PCM
+#define CFG_TUD_AUDIO_N_CHANNELS_TX 				1
+#define CFG_TUD_AUDIO_N_BYTES_PER_SAMPLE_TX			3
+
+// EP and buffer size - for isochronous EP´s, the buffer and EP size are equal (different sizes would not make sense)
+#define CFG_TUD_AUDIO_EPSIZE_IN    				45*CFG_TUD_AUDIO_N_BYTES_PER_SAMPLE_TX*CFG_TUD_AUDIO_N_CHANNELS_TX 	// 45 Samples (44.1 kHz) x 3 Bytes/Sample x 1 Channels
+#define CFG_TUD_AUDIO_TX_FIFO_SIZE 				45*4 									// 45 Samples (44.1 kHz) x 4 Bytes/Sample (1 word)
+
+// Number of Standard AS Interface Descriptors (4.9.1) defined per audio function - this is required to be able to remember the current alternate settings of these interfaces - We restrict us here to have a constant number for all audio functions (which means this has to be the maximum number of AS interfaces an audio function has and a second audio function with less AS interfaces just wastes a few bytes)
+#define CFG_TUD_AUDIO_N_AS_INT 			   		1
+
+// Size of control request buffer
+#define CFG_TUD_AUDIO_CTRL_BUF_SIZE 				64
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _TUSB_CONFIG_H_ */
diff --git a/examples/device/audio_test/src/usb_descriptors.c b/examples/device/audio_test/src/usb_descriptors.c
new file mode 100644
index 000000000..0b4f9b62c
--- /dev/null
+++ b/examples/device/audio_test/src/usb_descriptors.c
@@ -0,0 +1,167 @@
+/* 
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2019 Ha Thach (tinyusb.org)
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ */
+
+#include "tusb.h"
+
+/* A combination of interfaces must have a unique product id, since PC will save device driver after the first plug.
+ * Same VID/PID with different interface e.g MSC (first), then CDC (later) will possibly cause system error on PC.
+ *
+ * Auto ProductID layout's Bitmap:
+ *   [MSB]     AUDIO | MIDI | HID | MSC | CDC          [LSB]
+ */
+#define _PID_MAP(itf, n)  ( (CFG_TUD_##itf) << (n) )
+#define USB_PID           (0x4000 | _PID_MAP(CDC, 0) | _PID_MAP(MSC, 1) | _PID_MAP(HID, 2) | \
+    _PID_MAP(MIDI, 3) | _PID_MAP(AUDIO, 4) | _PID_MAP(VENDOR, 5) )
+
+//--------------------------------------------------------------------+
+// Device Descriptors
+//--------------------------------------------------------------------+
+tusb_desc_device_t const desc_device =
+{
+    .bLength            = sizeof(tusb_desc_device_t),
+    .bDescriptorType    = TUSB_DESC_DEVICE,
+    .bcdUSB             = 0x0200,
+
+    // Use Interface Association Descriptor (IAD) for CDC
+    // As required by USB Specs IAD's subclass must be common class (2) and protocol must be IAD (1)
+    .bDeviceClass       = TUSB_CLASS_MISC,
+    .bDeviceSubClass    = MISC_SUBCLASS_COMMON,
+    .bDeviceProtocol    = MISC_PROTOCOL_IAD,
+    .bMaxPacketSize0    = CFG_TUD_ENDPOINT0_SIZE,
+
+    .idVendor           = 0xCafe,
+    .idProduct          = USB_PID,
+    .bcdDevice          = 0x0100,
+
+    .iManufacturer      = 0x01,
+    .iProduct           = 0x02,
+    .iSerialNumber      = 0x03,
+
+    .bNumConfigurations = 0x01
+};
+
+// Invoked when received GET DEVICE DESCRIPTOR
+// Application return pointer to descriptor
+uint8_t const * tud_descriptor_device_cb(void)
+{
+  return (uint8_t const *) &desc_device;
+}
+
+//--------------------------------------------------------------------+
+// Configuration Descriptor
+//--------------------------------------------------------------------+
+enum
+{
+  ITF_NUM_AUDIO_CONTROL = 0,
+  ITF_NUM_AUDIO_STREAMING,
+  ITF_NUM_TOTAL
+};
+
+#define CONFIG_TOTAL_LEN    	(TUD_CONFIG_DESC_LEN + CFG_TUD_AUDIO * TUD_AUDIO_MIC_DESC_LEN)
+
+#if CFG_TUSB_MCU == OPT_MCU_LPC175X_6X || CFG_TUSB_MCU == OPT_MCU_LPC177X_8X || CFG_TUSB_MCU == OPT_MCU_LPC40XX
+// LPC 17xx and 40xx endpoint type (bulk/interrupt/iso) are fixed by its number
+// 0 control, 1 In, 2 Bulk, 3 Iso, 4 In etc ...
+#define EPNUM_AUDIO   0x03
+#else
+#define EPNUM_AUDIO   0x01
+#endif
+
+// These variables are required by the audio driver in audio_device.c
+
+// List of audio descriptor lengths which is required by audio driver - you need as many entries as CFG_TUD_AUDIO - unfortunately this is not possible to determine otherwise
+const uint16_t tud_audio_desc_lengths[] = {TUD_AUDIO_MIC_DESC_LEN};
+
+// TAKE CARE - THE NUMBER OF AUDIO STREAMING INTERFACES PER AUDIO FUNCTION MUST NOT EXCEED CFG_TUD_AUDIO_N_AS_INT - IF IT DOES INCREASE CFG_TUD_AUDIO_N_AS_INT IN tusb_config.h!
+
+uint8_t const desc_configuration[] =
+{
+    // Interface count, string index, total length, attribute, power in mA
+    TUD_CONFIG_DESCRIPTOR(1, ITF_NUM_TOTAL, 0, CONFIG_TOTAL_LEN, TUSB_DESC_CONFIG_ATT_REMOTE_WAKEUP, 100),
+
+    // Interface number, string index, EP Out & EP In address, EP size
+    TUD_AUDIO_MIC_DESCRIPTOR(/*_itfnum*/ ITF_NUM_AUDIO_CONTROL, /*_stridx*/ 0, /*_nBytesPerSample*/ 3, /*_nBitsUsedPerSample*/ 24, /*_epin*/ 0x80 | EPNUM_AUDIO, /*_epsize*/ 45*3)
+};
+
+// Invoked when received GET CONFIGURATION DESCRIPTOR
+// Application return pointer to descriptor
+// Descriptor contents must exist long enough for transfer to complete
+uint8_t const * tud_descriptor_configuration_cb(uint8_t index)
+{
+  (void) index; // for multiple configurations
+  return desc_configuration;
+}
+
+//--------------------------------------------------------------------+
+// String Descriptors
+//--------------------------------------------------------------------+
+
+// array of pointer to string descriptors
+char const* string_desc_arr [] =
+{
+    (const char[]) { 0x09, 0x04 }, 	// 0: is supported language is English (0x0409)
+    "PaniRCorp",                   	// 1: Manufacturer
+    "MicNode",              		// 2: Product
+    "123456",                      	// 3: Serials, should use chip ID
+    "UAC2",                 	 	// 4: Audio Interface
+};
+
+static uint16_t _desc_str[32];
+
+// Invoked when received GET STRING DESCRIPTOR request
+// Application return pointer to descriptor, whose contents must exist long enough for transfer to complete
+uint16_t const* tud_descriptor_string_cb(uint8_t index, uint16_t langid)
+{
+  (void) langid;
+
+  uint8_t chr_count;
+
+  if ( index == 0)
+  {
+    memcpy(&_desc_str[1], string_desc_arr[0], 2);
+    chr_count = 1;
+  }else
+  {
+    // Convert ASCII string into UTF-16
+
+    if ( !(index < sizeof(string_desc_arr)/sizeof(string_desc_arr[0])) ) return NULL;
+
+    const char* str = string_desc_arr[index];
+
+    // Cap at max char
+    chr_count = strlen(str);
+    if ( chr_count > 31 ) chr_count = 31;
+
+    for(uint8_t i=0; i<chr_count; i++)
+    {
+      _desc_str[1+i] = str[i];
+    }
+  }
+
+  // first byte is length (including header), second byte is string type
+  _desc_str[0] = (TUSB_DESC_STRING << 8 ) | (2*chr_count + 2);
+
+  return _desc_str;
+}
diff --git a/src/class/audio/audio.h b/src/class/audio/audio.h
index 8f2c0d214..1afacf0c4 100644
--- a/src/class/audio/audio.h
+++ b/src/class/audio/audio.h
@@ -2,6 +2,7 @@
  * The MIT License (MIT)
  *
  * Copyright (c) 2019 Ha Thach (tinyusb.org)
+ * Copyright (c) 2020 Reinhard Panhuber
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -38,786 +39,786 @@
 extern "C" {
 #endif
 
-/// Audio Device Class Codes
+  /// Audio Device Class Codes
 
-/// A.2 - Audio Function Subclass Codes
-typedef enum
-{
-	AUDIO_FUNCTION_SUBCLASS_UNDEFINED = 0x00,
-} audio_function_subclass_type_t;
+  /// A.2 - Audio Function Subclass Codes
+  typedef enum
+  {
+    AUDIO_FUNCTION_SUBCLASS_UNDEFINED = 0x00,
+  } audio_function_subclass_type_t;
 
-/// A.3 - Audio Function Protocol Codes
-typedef enum
-{
-	AUDIO_FUNC_PROTOCOL_CODE_UNDEF       = 0x00,
-	AUDIO_FUNC_PROTOCOL_CODE_V2          = 0x20, ///< Version 2.0
-} audio_function_protocol_code_t;
+  /// A.3 - Audio Function Protocol Codes
+  typedef enum
+  {
+    AUDIO_FUNC_PROTOCOL_CODE_UNDEF       = 0x00,
+    AUDIO_FUNC_PROTOCOL_CODE_V2          = 0x20, ///< Version 2.0
+  } audio_function_protocol_code_t;
 
-/// A.5 - Audio Interface Subclass Codes
-typedef enum
-{
-	AUDIO_SUBCLASS_UNDEFINED = 0x00,
-	AUDIO_SUBCLASS_CONTROL 		   , ///< Audio Control
-	AUDIO_SUBCLASS_STREAMING       , ///< Audio Streaming
-	AUDIO_SUBCLASS_MIDI_STREAMING  , ///< MIDI Streaming
-} audio_subclass_type_t;
+  /// A.5 - Audio Interface Subclass Codes
+  typedef enum
+  {
+    AUDIO_SUBCLASS_UNDEFINED = 0x00,
+    AUDIO_SUBCLASS_CONTROL 		   , ///< Audio Control
+    AUDIO_SUBCLASS_STREAMING       , ///< Audio Streaming
+    AUDIO_SUBCLASS_MIDI_STREAMING  , ///< MIDI Streaming
+  } audio_subclass_type_t;
 
-/// A.6 - Audio Interface Protocol Codes
-typedef enum
-{
-	AUDIO_INT_PROTOCOL_CODE_UNDEF 		= 0x00,
-	AUDIO_INT_PROTOCOL_CODE_V2   		= 0x20, ///< Version 2.0
-} audio_interface_protocol_code_t;
+  /// A.6 - Audio Interface Protocol Codes
+  typedef enum
+  {
+    AUDIO_INT_PROTOCOL_CODE_UNDEF 		= 0x00,
+    AUDIO_INT_PROTOCOL_CODE_V2   		= 0x20, ///< Version 2.0
+  } audio_interface_protocol_code_t;
 
-/// A.7 - Audio Function Category Codes
-typedef enum
-{
-	AUDIO_FUNC_UNDEF 			  = 0x00,
-	AUDIO_FUNC_DESKTOP_SPEAKER    = 0x01,
-	AUDIO_FUNC_HOME_THEATER       = 0x02,
-	AUDIO_FUNC_MICROPHONE         = 0x03,
-	AUDIO_FUNC_HEADSET            = 0x04,
-	AUDIO_FUNC_TELEPHONE          = 0x05,
-	AUDIO_FUNC_CONVERTER          = 0x06,
-	AUDIO_FUNC_SOUND_RECODER      = 0x07,
-	AUDIO_FUNC_IO_BOX             = 0x08,
-	AUDIO_FUNC_MUSICAL_INSTRUMENT = 0x09,
-	AUDIO_FUNC_PRO_AUDIO          = 0x0A,
-	AUDIO_FUNC_AUDIO_VIDEO        = 0x0B,
-	AUDIO_FUNC_CONTROL_PANEL      = 0x0C,
-	AUDIO_FUNC_OTHER      		  = 0xFF,
-} audio_function_code_t;
+  /// A.7 - Audio Function Category Codes
+  typedef enum
+  {
+    AUDIO_FUNC_UNDEF 			  = 0x00,
+    AUDIO_FUNC_DESKTOP_SPEAKER    = 0x01,
+    AUDIO_FUNC_HOME_THEATER       = 0x02,
+    AUDIO_FUNC_MICROPHONE         = 0x03,
+    AUDIO_FUNC_HEADSET            = 0x04,
+    AUDIO_FUNC_TELEPHONE          = 0x05,
+    AUDIO_FUNC_CONVERTER          = 0x06,
+    AUDIO_FUNC_SOUND_RECODER      = 0x07,
+    AUDIO_FUNC_IO_BOX             = 0x08,
+    AUDIO_FUNC_MUSICAL_INSTRUMENT = 0x09,
+    AUDIO_FUNC_PRO_AUDIO          = 0x0A,
+    AUDIO_FUNC_AUDIO_VIDEO        = 0x0B,
+    AUDIO_FUNC_CONTROL_PANEL      = 0x0C,
+    AUDIO_FUNC_OTHER      		  = 0xFF,
+  } audio_function_code_t;
 
-/// A.9 - Audio Class-Specific AC Interface Descriptor Subtypes UAC2
-typedef enum
-{
-	AUDIO_CS_AC_INTERFACE_AC_DESCRIPTOR_UNDEF   = 0x00,
-	AUDIO_CS_AC_INTERFACE_HEADER                = 0x01,
-	AUDIO_CS_AC_INTERFACE_INPUT_TERMINAL        = 0x02,
-	AUDIO_CS_AC_INTERFACE_OUTPUT_TERMINAL       = 0x03,
-	AUDIO_CS_AC_INTERFACE_MIXER_UNIT            = 0x04,
-	AUDIO_CS_AC_INTERFACE_SELECTOR_UNIT         = 0x05,
-	AUDIO_CS_AC_INTERFACE_FEATURE_UNIT          = 0x06,
-	AUDIO_CS_AC_INTERFACE_EFFECT_UNIT           = 0x07,
-	AUDIO_CS_AC_INTERFACE_PROCESSING_UNIT       = 0x08,
-	AUDIO_CS_AC_INTERFACE_EXTENSION_UNIT        = 0x09,
-	AUDIO_CS_AC_INTERFACE_CLOCK_SOURCE          = 0x0A,
-	AUDIO_CS_AC_INTERFACE_CLOCK_SELECTOR        = 0x0B,
-	AUDIO_CS_AC_INTERFACE_CLOCK_MULTIPLIER      = 0x0C,
-	AUDIO_CS_AC_INTERFACE_SAMPLE_RATE_CONVERTER = 0x0D,
-} audio_cs_ac_interface_subtype_t;
+  /// A.9 - Audio Class-Specific AC Interface Descriptor Subtypes UAC2
+  typedef enum
+  {
+    AUDIO_CS_AC_INTERFACE_AC_DESCRIPTOR_UNDEF   = 0x00,
+    AUDIO_CS_AC_INTERFACE_HEADER                = 0x01,
+    AUDIO_CS_AC_INTERFACE_INPUT_TERMINAL        = 0x02,
+    AUDIO_CS_AC_INTERFACE_OUTPUT_TERMINAL       = 0x03,
+    AUDIO_CS_AC_INTERFACE_MIXER_UNIT            = 0x04,
+    AUDIO_CS_AC_INTERFACE_SELECTOR_UNIT         = 0x05,
+    AUDIO_CS_AC_INTERFACE_FEATURE_UNIT          = 0x06,
+    AUDIO_CS_AC_INTERFACE_EFFECT_UNIT           = 0x07,
+    AUDIO_CS_AC_INTERFACE_PROCESSING_UNIT       = 0x08,
+    AUDIO_CS_AC_INTERFACE_EXTENSION_UNIT        = 0x09,
+    AUDIO_CS_AC_INTERFACE_CLOCK_SOURCE          = 0x0A,
+    AUDIO_CS_AC_INTERFACE_CLOCK_SELECTOR        = 0x0B,
+    AUDIO_CS_AC_INTERFACE_CLOCK_MULTIPLIER      = 0x0C,
+    AUDIO_CS_AC_INTERFACE_SAMPLE_RATE_CONVERTER = 0x0D,
+  } audio_cs_ac_interface_subtype_t;
 
-/// A.10 - Audio Class-Specific AS Interface Descriptor Subtypes UAC2
-typedef enum
-{
-	AUDIO_CS_AS_INTERFACE_AS_DESCRIPTOR_UNDEF 	= 0x00,
-	AUDIO_CS_AS_INTERFACE_AS_GENERAL            = 0x01,
-	AUDIO_CS_AS_INTERFACE_FORMAT_TYPE        	= 0x02,
-	AUDIO_CS_AS_INTERFACE_ENCODER       		= 0x03,
-	AUDIO_CS_AS_INTERFACE_DECODER       		= 0x04,
-} audio_cs_as_interface_subtype_t;
+  /// A.10 - Audio Class-Specific AS Interface Descriptor Subtypes UAC2
+  typedef enum
+  {
+    AUDIO_CS_AS_INTERFACE_AS_DESCRIPTOR_UNDEF 	= 0x00,
+    AUDIO_CS_AS_INTERFACE_AS_GENERAL            = 0x01,
+    AUDIO_CS_AS_INTERFACE_FORMAT_TYPE        	= 0x02,
+    AUDIO_CS_AS_INTERFACE_ENCODER       		= 0x03,
+    AUDIO_CS_AS_INTERFACE_DECODER       		= 0x04,
+  } audio_cs_as_interface_subtype_t;
 
-/// A.11 - Effect Unit Effect Types
-typedef enum
-{
-	AUDIO_EFFECT_TYPE_UNDEF 					= 0x00,
-	AUDIO_EFFECT_TYPE_PARAM_EQ_SECTION			= 0x01,
-	AUDIO_EFFECT_TYPE_REVERBERATION				= 0x02,
-	AUDIO_EFFECT_TYPE_MOD_DELAY 				= 0x03,
-	AUDIO_EFFECT_TYPE_DYN_RANGE_COMP			= 0x04,
-} audio_effect_unit_effect_type_t;
+  /// A.11 - Effect Unit Effect Types
+  typedef enum
+  {
+    AUDIO_EFFECT_TYPE_UNDEF 					= 0x00,
+    AUDIO_EFFECT_TYPE_PARAM_EQ_SECTION			= 0x01,
+    AUDIO_EFFECT_TYPE_REVERBERATION				= 0x02,
+    AUDIO_EFFECT_TYPE_MOD_DELAY 				= 0x03,
+    AUDIO_EFFECT_TYPE_DYN_RANGE_COMP			= 0x04,
+  } audio_effect_unit_effect_type_t;
 
-/// A.12 - Processing Unit Process Types
-typedef enum
-{
-	AUDIO_PROCESS_TYPE_UNDEF 					= 0x00,
-	AUDIO_PROCESS_TYPE_UP_DOWN_MIX 				= 0x01,
-	AUDIO_PROCESS_TYPE_DOLBY_PROLOGIC			= 0x02,
-	AUDIO_PROCESS_TYPE_STEREO_EXTENDER			= 0x03,
-} audio_processing_unit_process_type_t;
+  /// A.12 - Processing Unit Process Types
+  typedef enum
+  {
+    AUDIO_PROCESS_TYPE_UNDEF 					= 0x00,
+    AUDIO_PROCESS_TYPE_UP_DOWN_MIX 				= 0x01,
+    AUDIO_PROCESS_TYPE_DOLBY_PROLOGIC			= 0x02,
+    AUDIO_PROCESS_TYPE_STEREO_EXTENDER			= 0x03,
+  } audio_processing_unit_process_type_t;
 
-/// A.13 - Audio Class-Specific EP Descriptor Subtypes UAC2
-typedef enum
-{
-	AUDIO_CS_EP_SUBTYPE_UNDEF 					= 0x00,
-	AUDIO_CS_EP_SUBTYPE_GENERAL 				= 0x01,
-} audio_cs_ep_subtype_t;
+  /// A.13 - Audio Class-Specific EP Descriptor Subtypes UAC2
+  typedef enum
+  {
+    AUDIO_CS_EP_SUBTYPE_UNDEF 					= 0x00,
+    AUDIO_CS_EP_SUBTYPE_GENERAL 				= 0x01,
+  } audio_cs_ep_subtype_t;
 
-/// A.14 - Audio Class-Specific Request Codes
-typedef enum
-{
-	AUDIO_CS_REQ_UNDEF 							= 0x00,
-	AUDIO_CS_REQ_CUR 	 						= 0x01,
-	AUDIO_CS_REQ_RANGE 							= 0x02,
-	AUDIO_CS_REQ_MEM 							= 0x03,
-} audio_cs_req_t;
+  /// A.14 - Audio Class-Specific Request Codes
+  typedef enum
+  {
+    AUDIO_CS_REQ_UNDEF 							= 0x00,
+    AUDIO_CS_REQ_CUR 	 						= 0x01,
+    AUDIO_CS_REQ_RANGE 							= 0x02,
+    AUDIO_CS_REQ_MEM 							= 0x03,
+  } audio_cs_req_t;
 
-/// A.17 - Control Selector Codes
+  /// A.17 - Control Selector Codes
 
-/// A.17.1 - Clock Source Control Selectors
-typedef enum
-{
-	AUDIO_CS_CTRL_UNDEF 						= 0x00,
-	AUDIO_CS_CTRL_SAM_FREQ						= 0x01,
-	AUDIO_CS_CTRL_CLK_VALID						= 0x02,
-} audio_clock_src_control_selector_t;
+  /// A.17.1 - Clock Source Control Selectors
+  typedef enum
+  {
+    AUDIO_CS_CTRL_UNDEF 						= 0x00,
+    AUDIO_CS_CTRL_SAM_FREQ						= 0x01,
+    AUDIO_CS_CTRL_CLK_VALID						= 0x02,
+  } audio_clock_src_control_selector_t;
 
-/// A.17.2 - Clock Selector Control Selectors
-typedef enum
-{
-	AUDIO_CX_CTRL_UNDEF 						= 0x00,
-	AUDIO_CX_CTRL_CONTROL						= 0x01,
-} audio_clock_sel_control_selector_t;
+  /// A.17.2 - Clock Selector Control Selectors
+  typedef enum
+  {
+    AUDIO_CX_CTRL_UNDEF 						= 0x00,
+    AUDIO_CX_CTRL_CONTROL						= 0x01,
+  } audio_clock_sel_control_selector_t;
 
-/// A.17.3 - Clock Multiplier Control Selectors
-typedef enum
-{
-	AUDIO_CM_CTRL_UNDEF 						= 0x00,
-	AUDIO_CM_CTRL_NUMERATOR_CONTROL				= 0x01,
-	AUDIO_CM_CTRL_DENOMINATOR_CONTROL			= 0x02,
-} audio_clock_mul_control_selector_t;
+  /// A.17.3 - Clock Multiplier Control Selectors
+  typedef enum
+  {
+    AUDIO_CM_CTRL_UNDEF 						= 0x00,
+    AUDIO_CM_CTRL_NUMERATOR_CONTROL				= 0x01,
+    AUDIO_CM_CTRL_DENOMINATOR_CONTROL			= 0x02,
+  } audio_clock_mul_control_selector_t;
 
-/// A.17.4 - Terminal Control Selectors
-typedef enum
-{
-	AUDIO_TE_CTRL_UNDEF 						= 0x00,
-	AUDIO_TE_CTRL_COPY_PROTECT					= 0x01,
-	AUDIO_TE_CTRL_CONNECTOR						= 0x02,
-	AUDIO_TE_CTRL_OVERLOAD						= 0x03,
-	AUDIO_TE_CTRL_CLUSTER						= 0x04,
-	AUDIO_TE_CTRL_UNDERFLOW						= 0x05,
-	AUDIO_TE_CTRL_OVERFLOW						= 0x06,
-	AUDIO_TE_CTRL_LATENCY						= 0x07,
-} audio_terminal_control_selector_t;
+  /// A.17.4 - Terminal Control Selectors
+  typedef enum
+  {
+    AUDIO_TE_CTRL_UNDEF 						= 0x00,
+    AUDIO_TE_CTRL_COPY_PROTECT					= 0x01,
+    AUDIO_TE_CTRL_CONNECTOR						= 0x02,
+    AUDIO_TE_CTRL_OVERLOAD						= 0x03,
+    AUDIO_TE_CTRL_CLUSTER						= 0x04,
+    AUDIO_TE_CTRL_UNDERFLOW						= 0x05,
+    AUDIO_TE_CTRL_OVERFLOW						= 0x06,
+    AUDIO_TE_CTRL_LATENCY						= 0x07,
+  } audio_terminal_control_selector_t;
 
-/// A.17.5 - Mixer Control Selectors
-typedef enum
-{
-	AUDIO_MU_CTRL_UNDEF 						= 0x00,
-	AUDIO_MU_CTRL_MIXER							= 0x01,
-	AUDIO_MU_CTRL_CLUSTER						= 0x02,
-	AUDIO_MU_CTRL_UNDERFLOW						= 0x03,
-	AUDIO_MU_CTRL_OVERFLOW						= 0x04,
-	AUDIO_MU_CTRL_LATENCY						= 0x05,
-} audio_mixer_control_selector_t;
+  /// A.17.5 - Mixer Control Selectors
+  typedef enum
+  {
+    AUDIO_MU_CTRL_UNDEF 						= 0x00,
+    AUDIO_MU_CTRL_MIXER							= 0x01,
+    AUDIO_MU_CTRL_CLUSTER						= 0x02,
+    AUDIO_MU_CTRL_UNDERFLOW						= 0x03,
+    AUDIO_MU_CTRL_OVERFLOW						= 0x04,
+    AUDIO_MU_CTRL_LATENCY						= 0x05,
+  } audio_mixer_control_selector_t;
 
-/// A.17.6 - Selector Control Selectors
-typedef enum
-{
-	AUDIO_SU_CTRL_UNDEF 						= 0x00,
-	AUDIO_SU_CTRL_SELECTOR						= 0x01,
-	AUDIO_SU_CTRL_LATENCY 						= 0x02,
-} audio_sel_control_selector_t;
+  /// A.17.6 - Selector Control Selectors
+  typedef enum
+  {
+    AUDIO_SU_CTRL_UNDEF 						= 0x00,
+    AUDIO_SU_CTRL_SELECTOR						= 0x01,
+    AUDIO_SU_CTRL_LATENCY 						= 0x02,
+  } audio_sel_control_selector_t;
 
-/// A.17.7 - Feature Unit Control Selectors
-typedef enum
-{
-	AUDIO_FU_CTRL_UNDEF 						= 0x00,
-	AUDIO_FU_CTRL_MUTE  						= 0x01,
-	AUDIO_FU_CTRL_VOLUME						= 0x02,
-	AUDIO_FU_CTRL_BASS							= 0x03,
-	AUDIO_FU_CTRL_MID							= 0x04,
-	AUDIO_FU_CTRL_TREBLE						= 0x05,
-	AUDIO_FU_CTRL_GRAPHIC_EQUALIZER				= 0x06,
-	AUDIO_FU_CTRL_AGC							= 0x07,
-	AUDIO_FU_CTRL_DELAY							= 0x08,
-	AUDIO_FU_CTRL_BASS_BOOST					= 0x09,
-	AUDIO_FU_CTRL_LOUDNESS						= 0x0A,
-	AUDIO_FU_CTRL_INPUT_GAIN					= 0x0B,
-	AUDIO_FU_CTRL_GAIN_PAD						= 0x0C,
-	AUDIO_FU_CTRL_INVERTER						= 0x0D,
-	AUDIO_FU_CTRL_UNDERFLOW						= 0x0E,
-	AUDIO_FU_CTRL_OVERVLOW						= 0x0F,
-	AUDIO_FU_CTRL_LATENCY						= 0x10,
-} audio_feature_unit_control_selector_t;
+  /// A.17.7 - Feature Unit Control Selectors
+  typedef enum
+  {
+    AUDIO_FU_CTRL_UNDEF 						= 0x00,
+    AUDIO_FU_CTRL_MUTE  						= 0x01,
+    AUDIO_FU_CTRL_VOLUME						= 0x02,
+    AUDIO_FU_CTRL_BASS							= 0x03,
+    AUDIO_FU_CTRL_MID							= 0x04,
+    AUDIO_FU_CTRL_TREBLE						= 0x05,
+    AUDIO_FU_CTRL_GRAPHIC_EQUALIZER				= 0x06,
+    AUDIO_FU_CTRL_AGC							= 0x07,
+    AUDIO_FU_CTRL_DELAY							= 0x08,
+    AUDIO_FU_CTRL_BASS_BOOST					= 0x09,
+    AUDIO_FU_CTRL_LOUDNESS						= 0x0A,
+    AUDIO_FU_CTRL_INPUT_GAIN					= 0x0B,
+    AUDIO_FU_CTRL_GAIN_PAD						= 0x0C,
+    AUDIO_FU_CTRL_INVERTER						= 0x0D,
+    AUDIO_FU_CTRL_UNDERFLOW						= 0x0E,
+    AUDIO_FU_CTRL_OVERVLOW						= 0x0F,
+    AUDIO_FU_CTRL_LATENCY						= 0x10,
+  } audio_feature_unit_control_selector_t;
 
-/// A.17.8 Effect Unit Control Selectors
+  /// A.17.8 Effect Unit Control Selectors
 
-/// A.17.8.1 Parametric Equalizer Section Effect Unit Control Selectors
-typedef enum
-{
-	AUDIO_PE_CTRL_UNDEF 						= 0x00,
-	AUDIO_PE_CTRL_ENABLE 						= 0x01,
-	AUDIO_PE_CTRL_CENTERFREQ					= 0x02,
-	AUDIO_PE_CTRL_QFACTOR 						= 0x03,
-	AUDIO_PE_CTRL_GAIN	 						= 0x04,
-	AUDIO_PE_CTRL_UNDERFLOW						= 0x05,
-	AUDIO_PE_CTRL_OVERFLOW 						= 0x06,
-	AUDIO_PE_CTRL_LATENCY 						= 0x07,
-} audio_parametric_equalizer_control_selector_t;
+  /// A.17.8.1 Parametric Equalizer Section Effect Unit Control Selectors
+  typedef enum
+  {
+    AUDIO_PE_CTRL_UNDEF 						= 0x00,
+    AUDIO_PE_CTRL_ENABLE 						= 0x01,
+    AUDIO_PE_CTRL_CENTERFREQ					= 0x02,
+    AUDIO_PE_CTRL_QFACTOR 						= 0x03,
+    AUDIO_PE_CTRL_GAIN	 						= 0x04,
+    AUDIO_PE_CTRL_UNDERFLOW						= 0x05,
+    AUDIO_PE_CTRL_OVERFLOW 						= 0x06,
+    AUDIO_PE_CTRL_LATENCY 						= 0x07,
+  } audio_parametric_equalizer_control_selector_t;
 
-/// A.17.8.2 Reverberation Effect Unit Control Selectors
-typedef enum
-{
-	AUDIO_RV_CTRL_UNDEF 						= 0x00,
-	AUDIO_RV_CTRL_ENABLE 						= 0x01,
-	AUDIO_RV_CTRL_TYPE 							= 0x02,
-	AUDIO_RV_CTRL_LEVEL							= 0x03,
-	AUDIO_RV_CTRL_TIME 							= 0x04,
-	AUDIO_RV_CTRL_FEEDBACK						= 0x05,
-	AUDIO_RV_CTRL_PREDELAY 						= 0x06,
-	AUDIO_RV_CTRL_DENSITY						= 0x07,
-	AUDIO_RV_CTRL_HIFREQ_ROLLOFF				= 0x08,
-	AUDIO_RV_CTRL_UNDERFLOW						= 0x09,
-	AUDIO_RV_CTRL_OVERFLOW 						= 0x0A,
-	AUDIO_RV_CTRL_LATENCY 						= 0x0B,
-} audio_reverberation_effect_control_selector_t;
+  /// A.17.8.2 Reverberation Effect Unit Control Selectors
+  typedef enum
+  {
+    AUDIO_RV_CTRL_UNDEF 						= 0x00,
+    AUDIO_RV_CTRL_ENABLE 						= 0x01,
+    AUDIO_RV_CTRL_TYPE 							= 0x02,
+    AUDIO_RV_CTRL_LEVEL							= 0x03,
+    AUDIO_RV_CTRL_TIME 							= 0x04,
+    AUDIO_RV_CTRL_FEEDBACK						= 0x05,
+    AUDIO_RV_CTRL_PREDELAY 						= 0x06,
+    AUDIO_RV_CTRL_DENSITY						= 0x07,
+    AUDIO_RV_CTRL_HIFREQ_ROLLOFF				= 0x08,
+    AUDIO_RV_CTRL_UNDERFLOW						= 0x09,
+    AUDIO_RV_CTRL_OVERFLOW 						= 0x0A,
+    AUDIO_RV_CTRL_LATENCY 						= 0x0B,
+  } audio_reverberation_effect_control_selector_t;
 
-/// A.17.8.3 Modulation Delay Effect Unit Control Selectors
-typedef enum
-{
-	AUDIO_MD_CTRL_UNDEF 						= 0x00,
-	AUDIO_MD_CTRL_ENABLE 						= 0x01,
-	AUDIO_MD_CTRL_BALANCE 						= 0x02,
-	AUDIO_MD_CTRL_RATE 							= 0x03,
-	AUDIO_MD_CTRL_DEPTH 						= 0x04,
-	AUDIO_MD_CTRL_TIME 							= 0x05,
-	AUDIO_MD_CTRL_FEEDBACK 						= 0x06,
-	AUDIO_MD_CTRL_UNDERFLOW						= 0x07,
-	AUDIO_MD_CTRL_OVERFLOW						= 0x08,
-	AUDIO_MD_CTRL_LATENCY 						= 0x09,
-} audio_modulation_delay_control_selector_t;
+  /// A.17.8.3 Modulation Delay Effect Unit Control Selectors
+  typedef enum
+  {
+    AUDIO_MD_CTRL_UNDEF 						= 0x00,
+    AUDIO_MD_CTRL_ENABLE 						= 0x01,
+    AUDIO_MD_CTRL_BALANCE 						= 0x02,
+    AUDIO_MD_CTRL_RATE 							= 0x03,
+    AUDIO_MD_CTRL_DEPTH 						= 0x04,
+    AUDIO_MD_CTRL_TIME 							= 0x05,
+    AUDIO_MD_CTRL_FEEDBACK 						= 0x06,
+    AUDIO_MD_CTRL_UNDERFLOW						= 0x07,
+    AUDIO_MD_CTRL_OVERFLOW						= 0x08,
+    AUDIO_MD_CTRL_LATENCY 						= 0x09,
+  } audio_modulation_delay_control_selector_t;
 
-/// A.17.8.4 Dynamic Range Compressor Effect Unit Control Selectors
-typedef enum
-{
-	AUDIO_DR_CTRL_UNDEF 						= 0x00,
-	AUDIO_DR_CTRL_ENABLE 						= 0x01,
-	AUDIO_DR_CTRL_COMPRESSION_RATE				= 0x02,
-	AUDIO_DR_CTRL_MAXAMPL 						= 0x03,
-	AUDIO_DR_CTRL_THRESHOLD						= 0x04,
-	AUDIO_DR_CTRL_ATTACK_TIME					= 0x05,
-	AUDIO_DR_CTRL_RELEASE_TIME					= 0x06,
-	AUDIO_DR_CTRL_UNDERFLOW						= 0x07,
-	AUDIO_DR_CTRL_OVERFLOW 						= 0x08,
-	AUDIO_DR_CTRL_LATENCY 						= 0x09,
-} audio_dynamic_range_compression_control_selector_t;
+  /// A.17.8.4 Dynamic Range Compressor Effect Unit Control Selectors
+  typedef enum
+  {
+    AUDIO_DR_CTRL_UNDEF 						= 0x00,
+    AUDIO_DR_CTRL_ENABLE 						= 0x01,
+    AUDIO_DR_CTRL_COMPRESSION_RATE				= 0x02,
+    AUDIO_DR_CTRL_MAXAMPL 						= 0x03,
+    AUDIO_DR_CTRL_THRESHOLD						= 0x04,
+    AUDIO_DR_CTRL_ATTACK_TIME					= 0x05,
+    AUDIO_DR_CTRL_RELEASE_TIME					= 0x06,
+    AUDIO_DR_CTRL_UNDERFLOW						= 0x07,
+    AUDIO_DR_CTRL_OVERFLOW 						= 0x08,
+    AUDIO_DR_CTRL_LATENCY 						= 0x09,
+  } audio_dynamic_range_compression_control_selector_t;
 
-/// A.17.9 Processing Unit Control Selectors
+  /// A.17.9 Processing Unit Control Selectors
 
-/// A.17.9.1 Up/Down-mix Processing Unit Control Selectors
-typedef enum
-{
-	AUDIO_UD_CTRL_UNDEF 						= 0x00,
-	AUDIO_UD_CTRL_ENABLE 						= 0x01,
-	AUDIO_UD_CTRL_MODE_SELECT					= 0x02,
-	AUDIO_UD_CTRL_CLUSTER 						= 0x03,
-	AUDIO_UD_CTRL_UNDERFLOW						= 0x04,
-	AUDIO_UD_CTRL_OVERFLOW 						= 0x05,
-	AUDIO_UD_CTRL_LATENCY 						= 0x06,
-} audio_up_down_mix_control_selector_t;
+  /// A.17.9.1 Up/Down-mix Processing Unit Control Selectors
+  typedef enum
+  {
+    AUDIO_UD_CTRL_UNDEF 						= 0x00,
+    AUDIO_UD_CTRL_ENABLE 						= 0x01,
+    AUDIO_UD_CTRL_MODE_SELECT					= 0x02,
+    AUDIO_UD_CTRL_CLUSTER 						= 0x03,
+    AUDIO_UD_CTRL_UNDERFLOW						= 0x04,
+    AUDIO_UD_CTRL_OVERFLOW 						= 0x05,
+    AUDIO_UD_CTRL_LATENCY 						= 0x06,
+  } audio_up_down_mix_control_selector_t;
 
-/// A.17.9.2 Dolby Prologic ™ Processing Unit Control Selectors
-typedef enum
-{
-	AUDIO_DP_CTRL_UNDEF 						= 0x00,
-	AUDIO_DP_CTRL_ENABLE 						= 0x01,
-	AUDIO_DP_CTRL_MODE_SELECT					= 0x02,
-	AUDIO_DP_CTRL_CLUSTER 						= 0x03,
-	AUDIO_DP_CTRL_UNDERFLOW						= 0x04,
-	AUDIO_DP_CTRL_OVERFLOW 						= 0x05,
-	AUDIO_DP_CTRL_LATENCY 						= 0x06,
-} audio_dolby_prologic_control_selector_t;
+  /// A.17.9.2 Dolby Prologic ™ Processing Unit Control Selectors
+  typedef enum
+  {
+    AUDIO_DP_CTRL_UNDEF 						= 0x00,
+    AUDIO_DP_CTRL_ENABLE 						= 0x01,
+    AUDIO_DP_CTRL_MODE_SELECT					= 0x02,
+    AUDIO_DP_CTRL_CLUSTER 						= 0x03,
+    AUDIO_DP_CTRL_UNDERFLOW						= 0x04,
+    AUDIO_DP_CTRL_OVERFLOW 						= 0x05,
+    AUDIO_DP_CTRL_LATENCY 						= 0x06,
+  } audio_dolby_prologic_control_selector_t;
 
-/// A.17.9.3 Stereo Extender Processing Unit Control Selectors
-typedef enum
-{
-	AUDIO_ST_EXT_CTRL_UNDEF 					= 0x00,
-	AUDIO_ST_EXT_CTRL_ENABLE 					= 0x01,
-	AUDIO_ST_EXT_CTRL_WIDTH 					= 0x02,
-	AUDIO_ST_EXT_CTRL_UNDERFLOW					= 0x03,
-	AUDIO_ST_EXT_CTRL_OVERFLOW 					= 0x04,
-	AUDIO_ST_EXT_CTRL_LATENCY 					= 0x05,
-} audio_stereo_extender_control_selector_t;
+  /// A.17.9.3 Stereo Extender Processing Unit Control Selectors
+  typedef enum
+  {
+    AUDIO_ST_EXT_CTRL_UNDEF 					= 0x00,
+    AUDIO_ST_EXT_CTRL_ENABLE 					= 0x01,
+    AUDIO_ST_EXT_CTRL_WIDTH 					= 0x02,
+    AUDIO_ST_EXT_CTRL_UNDERFLOW					= 0x03,
+    AUDIO_ST_EXT_CTRL_OVERFLOW 					= 0x04,
+    AUDIO_ST_EXT_CTRL_LATENCY 					= 0x05,
+  } audio_stereo_extender_control_selector_t;
 
-/// A.17.10 Extension Unit Control Selectors
-typedef enum
-{
-	AUDIO_XU_CTRL_UNDEF 						= 0x00,
-	AUDIO_XU_CTRL_ENABLE 						= 0x01,
-	AUDIO_XU_CTRL_CLUSTER 						= 0x02,
-	AUDIO_XU_CTRL_UNDERFLOW						= 0x03,
-	AUDIO_XU_CTRL_OVERFLOW 						= 0x04,
-	AUDIO_XU_CTRL_LATENCY 						= 0x05,
-} audio_extension_unit_control_selector_t;
+  /// A.17.10 Extension Unit Control Selectors
+  typedef enum
+  {
+    AUDIO_XU_CTRL_UNDEF 						= 0x00,
+    AUDIO_XU_CTRL_ENABLE 						= 0x01,
+    AUDIO_XU_CTRL_CLUSTER 						= 0x02,
+    AUDIO_XU_CTRL_UNDERFLOW						= 0x03,
+    AUDIO_XU_CTRL_OVERFLOW 						= 0x04,
+    AUDIO_XU_CTRL_LATENCY 						= 0x05,
+  } audio_extension_unit_control_selector_t;
 
-/// A.17.11 AudioStreaming Interface Control Selectors
-typedef enum
-{
-	AUDIO_AS_CTRL_UNDEF 						= 0x00,
-	AUDIO_AS_CTRL_ACT_ALT_SETTING				= 0x01,
-	AUDIO_AS_CTRL_VAL_ALT_SETTINGS				= 0x02,
-	AUDIO_AS_CTRL_AUDIO_DATA_FORMAT				= 0x03,
-} audio_audiostreaming_interface_control_selector_t;
+  /// A.17.11 AudioStreaming Interface Control Selectors
+  typedef enum
+  {
+    AUDIO_AS_CTRL_UNDEF 						= 0x00,
+    AUDIO_AS_CTRL_ACT_ALT_SETTING				= 0x01,
+    AUDIO_AS_CTRL_VAL_ALT_SETTINGS				= 0x02,
+    AUDIO_AS_CTRL_AUDIO_DATA_FORMAT				= 0x03,
+  } audio_audiostreaming_interface_control_selector_t;
 
-/// A.17.12 Encoder Control Selectors
-typedef enum
-{
-	AUDIO_EN_CTRL_UNDEF 						= 0x00,
-	AUDIO_EN_CTRL_BIT_RATE 						= 0x01,
-	AUDIO_EN_CTRL_QUALITY 						= 0x02,
-	AUDIO_EN_CTRL_VBR  							= 0x03,
-	AUDIO_EN_CTRL_TYPE	 						= 0x04,
-	AUDIO_EN_CTRL_UNDERFLOW						= 0x05,
-	AUDIO_EN_CTRL_OVERFLOW 						= 0x06,
-	AUDIO_EN_CTRL_ENCODER_ERROR					= 0x07,
-	AUDIO_EN_CTRL_PARAM1 						= 0x08,
-	AUDIO_EN_CTRL_PARAM2 						= 0x09,
-	AUDIO_EN_CTRL_PARAM3 						= 0x0A,
-	AUDIO_EN_CTRL_PARAM4 						= 0x0B,
-	AUDIO_EN_CTRL_PARAM5 						= 0x0C,
-	AUDIO_EN_CTRL_PARAM6 						= 0x0D,
-	AUDIO_EN_CTRL_PARAM7 						= 0x0E,
-	AUDIO_EN_CTRL_PARAM8 						= 0x0F,
-} audio_encoder_control_selector_t;
+  /// A.17.12 Encoder Control Selectors
+  typedef enum
+  {
+    AUDIO_EN_CTRL_UNDEF 						= 0x00,
+    AUDIO_EN_CTRL_BIT_RATE 						= 0x01,
+    AUDIO_EN_CTRL_QUALITY 						= 0x02,
+    AUDIO_EN_CTRL_VBR  							= 0x03,
+    AUDIO_EN_CTRL_TYPE	 						= 0x04,
+    AUDIO_EN_CTRL_UNDERFLOW						= 0x05,
+    AUDIO_EN_CTRL_OVERFLOW 						= 0x06,
+    AUDIO_EN_CTRL_ENCODER_ERROR					= 0x07,
+    AUDIO_EN_CTRL_PARAM1 						= 0x08,
+    AUDIO_EN_CTRL_PARAM2 						= 0x09,
+    AUDIO_EN_CTRL_PARAM3 						= 0x0A,
+    AUDIO_EN_CTRL_PARAM4 						= 0x0B,
+    AUDIO_EN_CTRL_PARAM5 						= 0x0C,
+    AUDIO_EN_CTRL_PARAM6 						= 0x0D,
+    AUDIO_EN_CTRL_PARAM7 						= 0x0E,
+    AUDIO_EN_CTRL_PARAM8 						= 0x0F,
+  } audio_encoder_control_selector_t;
 
-/// A.17.13 Decoder Control Selectors
+  /// A.17.13 Decoder Control Selectors
 
-/// A.17.13.1 MPEG Decoder Control Selectors
-typedef enum
-{
-	AUDIO_MPD_CTRL_UNDEF 						= 0x00,
-	AUDIO_MPD_CTRL_DUAL_CHANNEL					= 0x01,
-	AUDIO_MPD_CTRL_SECOND_STEREO				= 0x02,
-	AUDIO_MPD_CTRL_MULTILINGUAL					= 0x03,
-	AUDIO_MPD_CTRL_DYN_RANGE					= 0x04,
-	AUDIO_MPD_CTRL_SCALING 						= 0x05,
-	AUDIO_MPD_CTRL_HILO_SCALING					= 0x06,
-	AUDIO_MPD_CTRL_UNDERFLOW					= 0x07,
-	AUDIO_MPD_CTRL_OVERFLOW 					= 0x08,
-	AUDIO_MPD_CTRL_DECODER_ERROR				= 0x09,
-} audio_MPEG_decoder_control_selector_t;
+  /// A.17.13.1 MPEG Decoder Control Selectors
+  typedef enum
+  {
+    AUDIO_MPD_CTRL_UNDEF 						= 0x00,
+    AUDIO_MPD_CTRL_DUAL_CHANNEL					= 0x01,
+    AUDIO_MPD_CTRL_SECOND_STEREO				= 0x02,
+    AUDIO_MPD_CTRL_MULTILINGUAL					= 0x03,
+    AUDIO_MPD_CTRL_DYN_RANGE					= 0x04,
+    AUDIO_MPD_CTRL_SCALING 						= 0x05,
+    AUDIO_MPD_CTRL_HILO_SCALING					= 0x06,
+    AUDIO_MPD_CTRL_UNDERFLOW					= 0x07,
+    AUDIO_MPD_CTRL_OVERFLOW 					= 0x08,
+    AUDIO_MPD_CTRL_DECODER_ERROR				= 0x09,
+  } audio_MPEG_decoder_control_selector_t;
 
-/// A.17.13.2 AC-3 Decoder Control Selectors
-typedef enum
-{
-	AUDIO_AD_CTRL_UNDEF 						= 0x00,
-	AUDIO_AD_CTRL_MODE	 						= 0x01,
-	AUDIO_AD_CTRL_DYN_RANGE						= 0x02,
-	AUDIO_AD_CTRL_SCALING 						= 0x03,
-	AUDIO_AD_CTRL_HILO_SCALING					= 0x04,
-	AUDIO_AD_CTRL_UNDERFLOW						= 0x05,
-	AUDIO_AD_CTRL_OVERFLOW 						= 0x06,
-	AUDIO_AD_CTRL_DECODER_ERROR					= 0x07,
-} audio_AC3_decoder_control_selector_t;
+  /// A.17.13.2 AC-3 Decoder Control Selectors
+  typedef enum
+  {
+    AUDIO_AD_CTRL_UNDEF 						= 0x00,
+    AUDIO_AD_CTRL_MODE	 						= 0x01,
+    AUDIO_AD_CTRL_DYN_RANGE						= 0x02,
+    AUDIO_AD_CTRL_SCALING 						= 0x03,
+    AUDIO_AD_CTRL_HILO_SCALING					= 0x04,
+    AUDIO_AD_CTRL_UNDERFLOW						= 0x05,
+    AUDIO_AD_CTRL_OVERFLOW 						= 0x06,
+    AUDIO_AD_CTRL_DECODER_ERROR					= 0x07,
+  } audio_AC3_decoder_control_selector_t;
 
-/// A.17.13.3 WMA Decoder Control Selectors
-typedef enum
-{
-	AUDIO_WD_CTRL_UNDEF 						= 0x00,
-	AUDIO_WD_CTRL_UNDERFLOW						= 0x01,
-	AUDIO_WD_CTRL_OVERFLOW 						= 0x02,
-	AUDIO_WD_CTRL_DECODER_ERROR					= 0x03,
-} audio_WMA_decoder_control_selector_t;
+  /// A.17.13.3 WMA Decoder Control Selectors
+  typedef enum
+  {
+    AUDIO_WD_CTRL_UNDEF 						= 0x00,
+    AUDIO_WD_CTRL_UNDERFLOW						= 0x01,
+    AUDIO_WD_CTRL_OVERFLOW 						= 0x02,
+    AUDIO_WD_CTRL_DECODER_ERROR					= 0x03,
+  } audio_WMA_decoder_control_selector_t;
 
-/// A.17.13.4 DTS Decoder Control Selectors
-typedef enum
-{
-	AUDIO_DD_CTRL_UNDEF 						= 0x00,
-	AUDIO_DD_CTRL_UNDERFLOW						= 0x01,
-	AUDIO_DD_CTRL_OVERFLOW 						= 0x02,
-	AUDIO_DD_CTRL_DECODER_ERROR					= 0x03,
-} audio_DTS_decoder_control_selector_t;
+  /// A.17.13.4 DTS Decoder Control Selectors
+  typedef enum
+  {
+    AUDIO_DD_CTRL_UNDEF 						= 0x00,
+    AUDIO_DD_CTRL_UNDERFLOW						= 0x01,
+    AUDIO_DD_CTRL_OVERFLOW 						= 0x02,
+    AUDIO_DD_CTRL_DECODER_ERROR					= 0x03,
+  } audio_DTS_decoder_control_selector_t;
 
-/// A.17.14 Endpoint Control Selectors
-typedef enum
-{
-	AUDIO_EP_CTRL_UNDEF 						= 0x00,
-	AUDIO_EP_CTRL_PITCH 						= 0x01,
-	AUDIO_EP_CTRL_DATA_OVERRUN					= 0x02,
-	AUDIO_EP_CTRL_DATA_UNDERRUN					= 0x03,
-} audio_EP_control_selector_t;
+  /// A.17.14 Endpoint Control Selectors
+  typedef enum
+  {
+    AUDIO_EP_CTRL_UNDEF 						= 0x00,
+    AUDIO_EP_CTRL_PITCH 						= 0x01,
+    AUDIO_EP_CTRL_DATA_OVERRUN					= 0x02,
+    AUDIO_EP_CTRL_DATA_UNDERRUN					= 0x03,
+  } audio_EP_control_selector_t;
 
-/// Terminal Types
+  /// Terminal Types
 
-/// 2.1 - Audio Class-Terminal Types UAC2
-typedef enum
-{
-	AUDIO_TERM_TYPE_USB_UNDEFINED 		= 0x0100,
-	AUDIO_TERM_TYPE_USB_STREAMING 		= 0x0101,
-	AUDIO_TERM_TYPE_USB_VENDOR_SPEC		= 0x01FF,
-} audio_terminal_type_t;
+  /// 2.1 - Audio Class-Terminal Types UAC2
+  typedef enum
+  {
+    AUDIO_TERM_TYPE_USB_UNDEFINED 		= 0x0100,
+    AUDIO_TERM_TYPE_USB_STREAMING 		= 0x0101,
+    AUDIO_TERM_TYPE_USB_VENDOR_SPEC		= 0x01FF,
+  } audio_terminal_type_t;
 
-/// 2.2 - Audio Class-Input Terminal Types UAC2
-typedef enum
-{
-	AUDIO_TERM_TYPE_IN_UNDEFINED 		= 0x0200,
-	AUDIO_TERM_TYPE_IN_GENERIC_MIC 		= 0x0201,
-	AUDIO_TERM_TYPE_IN_DESKTOP_MIC 		= 0x0202,
-	AUDIO_TERM_TYPE_IN_PERSONAL_MIC 	= 0x0203,
-	AUDIO_TERM_TYPE_IN_OMNI_MIC 		= 0x0204,
-	AUDIO_TERM_TYPE_IN_ARRAY_MIC 		= 0x0205,
-	AUDIO_TERM_TYPE_IN_PROC_ARRAY_MIC 	= 0x0206,
-} audio_terminal_input_type_t;
+  /// 2.2 - Audio Class-Input Terminal Types UAC2
+  typedef enum
+  {
+    AUDIO_TERM_TYPE_IN_UNDEFINED 		= 0x0200,
+    AUDIO_TERM_TYPE_IN_GENERIC_MIC 		= 0x0201,
+    AUDIO_TERM_TYPE_IN_DESKTOP_MIC 		= 0x0202,
+    AUDIO_TERM_TYPE_IN_PERSONAL_MIC 	= 0x0203,
+    AUDIO_TERM_TYPE_IN_OMNI_MIC 		= 0x0204,
+    AUDIO_TERM_TYPE_IN_ARRAY_MIC 		= 0x0205,
+    AUDIO_TERM_TYPE_IN_PROC_ARRAY_MIC 	= 0x0206,
+  } audio_terminal_input_type_t;
 
-/// 2.3 - Audio Class-Output Terminal Types UAC2
-typedef enum
-{
-	AUDIO_TERM_TYPE_OUT_UNDEFINED 				= 0x0300,
-	AUDIO_TERM_TYPE_OUT_GENERIC_SPEAKER 		= 0x0301,
-	AUDIO_TERM_TYPE_OUT_HEADPHONES 				= 0x0302,
-	AUDIO_TERM_TYPE_OUT_HEAD_MNT_DISP_AUIDO 	= 0x0303,
-	AUDIO_TERM_TYPE_OUT_DESKTOP_SPEAKER 		= 0x0304,
-	AUDIO_TERM_TYPE_OUT_ROOM_SPEAKER	 		= 0x0305,
-	AUDIO_TERM_TYPE_OUT_COMMUNICATION_SPEAKER 	= 0x0306,
-	AUDIO_TERM_TYPE_OUT_LOW_FRQ_EFFECTS_SPEAKER = 0x0307,
-} audio_terminal_output_type_t;
+  /// 2.3 - Audio Class-Output Terminal Types UAC2
+  typedef enum
+  {
+    AUDIO_TERM_TYPE_OUT_UNDEFINED 				= 0x0300,
+    AUDIO_TERM_TYPE_OUT_GENERIC_SPEAKER 		= 0x0301,
+    AUDIO_TERM_TYPE_OUT_HEADPHONES 				= 0x0302,
+    AUDIO_TERM_TYPE_OUT_HEAD_MNT_DISP_AUIDO 	= 0x0303,
+    AUDIO_TERM_TYPE_OUT_DESKTOP_SPEAKER 		= 0x0304,
+    AUDIO_TERM_TYPE_OUT_ROOM_SPEAKER	 		= 0x0305,
+    AUDIO_TERM_TYPE_OUT_COMMUNICATION_SPEAKER 	= 0x0306,
+    AUDIO_TERM_TYPE_OUT_LOW_FRQ_EFFECTS_SPEAKER = 0x0307,
+  } audio_terminal_output_type_t;
 
-/// Rest is yet to be implemented
+  /// Rest is yet to be implemented
 
-/// Additional Audio Device Class Codes - Source: Audio Data Formats
+  /// Additional Audio Device Class Codes - Source: Audio Data Formats
 
-/// A.1 - Audio Class-Format Type Codes UAC2
-typedef enum
-{
-	AUDIO_FORMAT_TYPE_UNDEFINED 	= 0x00,
-	AUDIO_FORMAT_TYPE_I 			= 0x01,
-	AUDIO_FORMAT_TYPE_II 			= 0x02,
-	AUDIO_FORMAT_TYPE_III 			= 0x03,
-	AUDIO_FORMAT_TYPE_IV 			= 0x04,
-	AUDIO_EXT_FORMAT_TYPE_I 		= 0x81,
-	AUDIO_EXT_FORMAT_TYPE_II 		= 0x82,
-	AUDIO_EXT_FORMAT_TYPE_III 		= 0x83,
-} audio_format_type_t;
+  /// A.1 - Audio Class-Format Type Codes UAC2
+  typedef enum
+  {
+    AUDIO_FORMAT_TYPE_UNDEFINED 	= 0x00,
+    AUDIO_FORMAT_TYPE_I 			= 0x01,
+    AUDIO_FORMAT_TYPE_II 			= 0x02,
+    AUDIO_FORMAT_TYPE_III 			= 0x03,
+    AUDIO_FORMAT_TYPE_IV 			= 0x04,
+    AUDIO_EXT_FORMAT_TYPE_I 		= 0x81,
+    AUDIO_EXT_FORMAT_TYPE_II 		= 0x82,
+    AUDIO_EXT_FORMAT_TYPE_III 		= 0x83,
+  } audio_format_type_t;
 
-/// A.2.1 - Audio Class-Audio Data Format Type I UAC2
-typedef enum
-{
-	AUDIO_DATA_FORMAT_TYPE_I_PCM 			= (uint32_t) (1 << 0),
-	AUDIO_DATA_FORMAT_TYPE_I_PCM8 			= (uint32_t) (1 << 1),
-	AUDIO_DATA_FORMAT_TYPE_I_IEEE_FLOAT 	= (uint32_t) (1 << 2),
-	AUDIO_DATA_FORMAT_TYPE_I_ALAW 			= (uint32_t) (1 << 3),
-	AUDIO_DATA_FORMAT_TYPE_I_MULAW 			= (uint32_t) (1 << 4),
-	AUDIO_DATA_FORMAT_TYPE_I_RAW_DATA		= (uint32_t) (1 << 31),
-} audio_data_format_type_I_t;
+  /// A.2.1 - Audio Class-Audio Data Format Type I UAC2
+  typedef enum
+  {
+    AUDIO_DATA_FORMAT_TYPE_I_PCM 			= (uint32_t) (1 << 0),
+    AUDIO_DATA_FORMAT_TYPE_I_PCM8 			= (uint32_t) (1 << 1),
+    AUDIO_DATA_FORMAT_TYPE_I_IEEE_FLOAT 	= (uint32_t) (1 << 2),
+    AUDIO_DATA_FORMAT_TYPE_I_ALAW 			= (uint32_t) (1 << 3),
+    AUDIO_DATA_FORMAT_TYPE_I_MULAW 			= (uint32_t) (1 << 4),
+    AUDIO_DATA_FORMAT_TYPE_I_RAW_DATA		= (uint32_t) (1 << 31),
+  } audio_data_format_type_I_t;
 
-/// All remaining definitions are taken from the descriptor descriptions in the UAC2 main specification
+  /// All remaining definitions are taken from the descriptor descriptions in the UAC2 main specification
 
-/// Isochronous End Point Attributes
-typedef enum
-{
-	TUSB_ISO_EP_ATT_ASYNCHRONOUS 	= 0x04,
-	TUSB_ISO_EP_ATT_ADAPTIVE 		= 0x08,
-	TUSB_ISO_EP_ATT_SYNCHRONOUS 	= 0x0C,
-	TUSB_ISO_EP_ATT_DATA 			= 0x00,	///< Data End Point
-	TUSB_ISO_EP_ATT_FB 				= 0x20, ///< Feedback End Point
-} tusb_iso_ep_attribute_t;
+  /// Isochronous End Point Attributes
+  typedef enum
+  {
+    TUSB_ISO_EP_ATT_ASYNCHRONOUS 	= 0x04,
+    TUSB_ISO_EP_ATT_ADAPTIVE 		= 0x08,
+    TUSB_ISO_EP_ATT_SYNCHRONOUS 	= 0x0C,
+    TUSB_ISO_EP_ATT_DATA 			= 0x00,	///< Data End Point
+    TUSB_ISO_EP_ATT_FB 				= 0x20, ///< Feedback End Point
+  } tusb_iso_ep_attribute_t;
 
-/// Audio Class-Control Values UAC2
-typedef enum
-{
-	AUDIO_CTRL_NONE		= 0x00, 		///< No Host access
-	AUDIO_CTRL_R 		= 0x01, 		///< Host read access only
-	AUDIO_CTRL_RW 		= 0x03, 		///< Host read write access
-} audio_control_t;
+  /// Audio Class-Control Values UAC2
+  typedef enum
+  {
+    AUDIO_CTRL_NONE		= 0x00, 		///< No Host access
+    AUDIO_CTRL_R 		= 0x01, 		///< Host read access only
+    AUDIO_CTRL_RW 		= 0x03, 		///< Host read write access
+  } audio_control_t;
 
-/// Audio Class-Specific AC Interface Descriptor Controls UAC2
-typedef enum
-{
-	AUDIO_CS_AS_INTERFACE_CTRL_LATENCY_POS 	= 0,
-} audio_cs_ac_interface_control_pos_t;
+  /// Audio Class-Specific AC Interface Descriptor Controls UAC2
+  typedef enum
+  {
+    AUDIO_CS_AS_INTERFACE_CTRL_LATENCY_POS 	= 0,
+  } audio_cs_ac_interface_control_pos_t;
 
-/// Audio Class-Specific AS Interface Descriptor Controls UAC2
-typedef enum
-{
-	AUDIO_CS_AS_INTERFACE_CTRL_ACTIVE_ALT_SET_POS 	= 0,
-	AUDIO_CS_AS_INTERFACE_CTRL_VALID_ALT_SET_POS	= 2,
-} audio_cs_as_interface_control_pos_t;
+  /// Audio Class-Specific AS Interface Descriptor Controls UAC2
+  typedef enum
+  {
+    AUDIO_CS_AS_INTERFACE_CTRL_ACTIVE_ALT_SET_POS 	= 0,
+    AUDIO_CS_AS_INTERFACE_CTRL_VALID_ALT_SET_POS	= 2,
+  } audio_cs_as_interface_control_pos_t;
 
-/// Audio Class-Specific AS Isochronous Data EP Attributes UAC2
-typedef enum
-{
-	AUDIO_CS_AS_ISO_DATA_EP_ATT_MAX_PACKETS_ONLY 	= 0x80,
-	AUDIO_CS_AS_ISO_DATA_EP_ATT_NON_MAX_PACKETS_OK 	= 0x00,
-} audio_cs_as_iso_data_ep_attribute_t;
+  /// Audio Class-Specific AS Isochronous Data EP Attributes UAC2
+  typedef enum
+  {
+    AUDIO_CS_AS_ISO_DATA_EP_ATT_MAX_PACKETS_ONLY 	= 0x80,
+    AUDIO_CS_AS_ISO_DATA_EP_ATT_NON_MAX_PACKETS_OK 	= 0x00,
+  } audio_cs_as_iso_data_ep_attribute_t;
 
-/// Audio Class-Specific AS Isochronous Data EP Controls UAC2
-typedef enum
-{
-	AUDIO_CS_AS_ISO_DATA_EP_CTRL_PITCH_POS 			= 0,
-	AUDIO_CS_AS_ISO_DATA_EP_CTRL_DATA_OVERRUN_POS 	= 2,
-	AUDIO_CS_AS_ISO_DATA_EP_CTRL_DATA_UNDERRUN_POS 	= 4,
-} audio_cs_as_iso_data_ep_control_pos_t;
+  /// Audio Class-Specific AS Isochronous Data EP Controls UAC2
+  typedef enum
+  {
+    AUDIO_CS_AS_ISO_DATA_EP_CTRL_PITCH_POS 			= 0,
+    AUDIO_CS_AS_ISO_DATA_EP_CTRL_DATA_OVERRUN_POS 	= 2,
+    AUDIO_CS_AS_ISO_DATA_EP_CTRL_DATA_UNDERRUN_POS 	= 4,
+  } audio_cs_as_iso_data_ep_control_pos_t;
 
-/// Audio Class-Specific AS Isochronous Data EP Lock Delay Units UAC2
-typedef enum
-{
-	AUDIO_CS_AS_ISO_DATA_EP_LOCK_DELAY_UNIT_UNDEFINED 		= 0x00,
-	AUDIO_CS_AS_ISO_DATA_EP_LOCK_DELAY_UNIT_MILLISEC 		= 0x01,
-	AUDIO_CS_AS_ISO_DATA_EP_LOCK_DELAY_UNIT_PCM_SAMPLES 	= 0x02,
-} audio_cs_as_iso_data_ep_lock_delay_unit_t;
+  /// Audio Class-Specific AS Isochronous Data EP Lock Delay Units UAC2
+  typedef enum
+  {
+    AUDIO_CS_AS_ISO_DATA_EP_LOCK_DELAY_UNIT_UNDEFINED 		= 0x00,
+    AUDIO_CS_AS_ISO_DATA_EP_LOCK_DELAY_UNIT_MILLISEC 		= 0x01,
+    AUDIO_CS_AS_ISO_DATA_EP_LOCK_DELAY_UNIT_PCM_SAMPLES 	= 0x02,
+  } audio_cs_as_iso_data_ep_lock_delay_unit_t;
 
-/// Audio Class-Clock Source Attributes UAC2
-typedef enum
-{
-	AUDIO_CLOCK_SOURCE_ATT_EXT_CLK 		= 0x00,
-	AUDIO_CLOCK_SOURCE_ATT_INT_FIX_CLK 	= 0x01,
-	AUDIO_CLOCK_SOURCE_ATT_INT_VAR_CLK 	= 0x02,
-	AUDIO_CLOCK_SOURCE_ATT_INT_PRO_CLK 	= 0x03,
-	AUDIO_CLOCK_SOURCE_ATT_CLK_SYC_SOF 	= 0x04,
-} audio_clock_source_attribute_t;
+  /// Audio Class-Clock Source Attributes UAC2
+  typedef enum
+  {
+    AUDIO_CLOCK_SOURCE_ATT_EXT_CLK 		= 0x00,
+    AUDIO_CLOCK_SOURCE_ATT_INT_FIX_CLK 	= 0x01,
+    AUDIO_CLOCK_SOURCE_ATT_INT_VAR_CLK 	= 0x02,
+    AUDIO_CLOCK_SOURCE_ATT_INT_PRO_CLK 	= 0x03,
+    AUDIO_CLOCK_SOURCE_ATT_CLK_SYC_SOF 	= 0x04,
+  } audio_clock_source_attribute_t;
 
-/// Audio Class-Clock Source Controls UAC2
-typedef enum
-{
-	AUDIO_CLOCK_SOURCE_CTRL_CLK_FRQ_POS 	= 0,
-	AUDIO_CLOCK_SOURCE_CTRL_CLK_VAL_POS 	= 2,
-} audio_clock_source_control_pos_t;
+  /// Audio Class-Clock Source Controls UAC2
+  typedef enum
+  {
+    AUDIO_CLOCK_SOURCE_CTRL_CLK_FRQ_POS 	= 0,
+    AUDIO_CLOCK_SOURCE_CTRL_CLK_VAL_POS 	= 2,
+  } audio_clock_source_control_pos_t;
 
-/// Audio Class-Clock Selector Controls UAC2
-typedef enum
-{
-	AUDIO_CLOCK_SELECTOR_CTRL_POS 	= 0,
-} audio_clock_selector_control_pos_t;
+  /// Audio Class-Clock Selector Controls UAC2
+  typedef enum
+  {
+    AUDIO_CLOCK_SELECTOR_CTRL_POS 	= 0,
+  } audio_clock_selector_control_pos_t;
 
-/// Audio Class-Clock Multiplier Controls UAC2
-typedef enum
-{
-	AUDIO_CLOCK_MULTIPLIER_CTRL_NUMERATOR_POS 		= 0,
-	AUDIO_CLOCK_MULTIPLIER_CTRL_DENOMINATOR_POS 	= 2,
-} audio_clock_multiplier_control_pos_t;
+  /// Audio Class-Clock Multiplier Controls UAC2
+  typedef enum
+  {
+    AUDIO_CLOCK_MULTIPLIER_CTRL_NUMERATOR_POS 		= 0,
+    AUDIO_CLOCK_MULTIPLIER_CTRL_DENOMINATOR_POS 	= 2,
+  } audio_clock_multiplier_control_pos_t;
 
-/// Audio Class-Input Terminal Controls UAC2
-typedef enum
-{
-	AUDIO_IN_TERM_CTRL_CPY_PROT_POS 	= 0,
-	AUDIO_IN_TERM_CTRL_CONNECTOR_POS 	= 2,
-	AUDIO_IN_TERM_CTRL_OVERLOAD_POS 	= 4,
-	AUDIO_IN_TERM_CTRL_CLUSTER_POS 		= 6,
-	AUDIO_IN_TERM_CTRL_UNDERFLOW_POS 	= 8,
-	AUDIO_IN_TERM_CTRL_OVERFLOW_POS 	= 10,
-} audio_terminal_input_control_pos_t;
+  /// Audio Class-Input Terminal Controls UAC2
+  typedef enum
+  {
+    AUDIO_IN_TERM_CTRL_CPY_PROT_POS 	= 0,
+    AUDIO_IN_TERM_CTRL_CONNECTOR_POS 	= 2,
+    AUDIO_IN_TERM_CTRL_OVERLOAD_POS 	= 4,
+    AUDIO_IN_TERM_CTRL_CLUSTER_POS 		= 6,
+    AUDIO_IN_TERM_CTRL_UNDERFLOW_POS 	= 8,
+    AUDIO_IN_TERM_CTRL_OVERFLOW_POS 	= 10,
+  } audio_terminal_input_control_pos_t;
 
-/// Audio Class-Output Terminal Controls UAC2
-typedef enum
-{
-	AUDIO_OUT_TERM_CTRL_CPY_PROT_POS 	= 0,
-	AUDIO_OUT_TERM_CTRL_CONNECTOR_POS 	= 2,
-	AUDIO_OUT_TERM_CTRL_OVERLOAD_POS 	= 4,
-	AUDIO_OUT_TERM_CTRL_UNDERFLOW_POS 	= 6,
-	AUDIO_OUT_TERM_CTRL_OVERFLOW_POS 	= 8,
-} audio_terminal_output_control_pos_t;
+  /// Audio Class-Output Terminal Controls UAC2
+  typedef enum
+  {
+    AUDIO_OUT_TERM_CTRL_CPY_PROT_POS 	= 0,
+    AUDIO_OUT_TERM_CTRL_CONNECTOR_POS 	= 2,
+    AUDIO_OUT_TERM_CTRL_OVERLOAD_POS 	= 4,
+    AUDIO_OUT_TERM_CTRL_UNDERFLOW_POS 	= 6,
+    AUDIO_OUT_TERM_CTRL_OVERFLOW_POS 	= 8,
+  } audio_terminal_output_control_pos_t;
 
-/// Audio Class-Feature Unit Controls UAC2
-typedef enum
-{
-	AUDIO_FEATURE_UNIT_CTRL_MUTE_POS 			= 0,
-	AUDIO_FEATURE_UNIT_CTRL_VOLUME_POS 			= 2,
-	AUDIO_FEATURE_UNIT_CTRL_BASS_POS 			= 4,
-	AUDIO_FEATURE_UNIT_CTRL_MID_POS 			= 6,
-	AUDIO_FEATURE_UNIT_CTRL_TREBLE_POS 			= 8,
-	AUDIO_FEATURE_UNIT_CTRL_GRAPHIC_EQU_POS 	= 10,
-	AUDIO_FEATURE_UNIT_CTRL_AGC_POS 			= 12,
-	AUDIO_FEATURE_UNIT_CTRL_DELAY_POS 			= 14,
-	AUDIO_FEATURE_UNIT_CTRL_BASS_BOOST_POS 		= 16,
-	AUDIO_FEATURE_UNIT_CTRL_LOUDNESS_POS		= 18,
-	AUDIO_FEATURE_UNIT_CTRL_INPUT_GAIN_POS		= 20,
-	AUDIO_FEATURE_UNIT_CTRL_INPUT_GAIN_PAD_POS	= 22,
-	AUDIO_FEATURE_UNIT_CTRL_PHASE_INV_POS		= 24,
-	AUDIO_FEATURE_UNIT_CTRL_UNDERFLOW_POS		= 26,
-	AUDIO_FEATURE_UNIT_CTRL_OVERFLOW_POS		= 28,
-} audio_feature_unit_control_pos_t;
+  /// Audio Class-Feature Unit Controls UAC2
+  typedef enum
+  {
+    AUDIO_FEATURE_UNIT_CTRL_MUTE_POS 			= 0,
+    AUDIO_FEATURE_UNIT_CTRL_VOLUME_POS 			= 2,
+    AUDIO_FEATURE_UNIT_CTRL_BASS_POS 			= 4,
+    AUDIO_FEATURE_UNIT_CTRL_MID_POS 			= 6,
+    AUDIO_FEATURE_UNIT_CTRL_TREBLE_POS 			= 8,
+    AUDIO_FEATURE_UNIT_CTRL_GRAPHIC_EQU_POS 	= 10,
+    AUDIO_FEATURE_UNIT_CTRL_AGC_POS 			= 12,
+    AUDIO_FEATURE_UNIT_CTRL_DELAY_POS 			= 14,
+    AUDIO_FEATURE_UNIT_CTRL_BASS_BOOST_POS 		= 16,
+    AUDIO_FEATURE_UNIT_CTRL_LOUDNESS_POS		= 18,
+    AUDIO_FEATURE_UNIT_CTRL_INPUT_GAIN_POS		= 20,
+    AUDIO_FEATURE_UNIT_CTRL_INPUT_GAIN_PAD_POS	= 22,
+    AUDIO_FEATURE_UNIT_CTRL_PHASE_INV_POS		= 24,
+    AUDIO_FEATURE_UNIT_CTRL_UNDERFLOW_POS		= 26,
+    AUDIO_FEATURE_UNIT_CTRL_OVERFLOW_POS		= 28,
+  } audio_feature_unit_control_pos_t;
 
-/// Audio Class-Audio Channel Configuration UAC2
-typedef enum
-{
-	AUDIO_CHANNEL_CONFIG_NON_PREDEFINED 			= 0x00000000,
-	AUDIO_CHANNEL_CONFIG_FRONT_LEFT 				= 0x00000001,
-	AUDIO_CHANNEL_CONFIG_FRONT_RIGHT 				= 0x00000002,
-	AUDIO_CHANNEL_CONFIG_FRONT_CENTER 				= 0x00000004,
-	AUDIO_CHANNEL_CONFIG_LOW_FRQ_EFFECTS 			= 0x00000008,
-	AUDIO_CHANNEL_CONFIG_BACK_LEFT 					= 0x00000010,
-	AUDIO_CHANNEL_CONFIG_BACK_RIGHT 				= 0x00000020,
-	AUDIO_CHANNEL_CONFIG_FRONT_LEFT_OF_CENTER 		= 0x00000040,
-	AUDIO_CHANNEL_CONFIG_FRONT_RIGHT_OF_CENTER 		= 0x00000080,
-	AUDIO_CHANNEL_CONFIG_BACK_CENTER 				= 0x00000100,
-	AUDIO_CHANNEL_CONFIG_SIDE_LEFT 					= 0x00000200,
-	AUDIO_CHANNEL_CONFIG_SIDE_RIGHT 				= 0x00000400,
-	AUDIO_CHANNEL_CONFIG_TOP_CENTER 				= 0x00000800,
-	AUDIO_CHANNEL_CONFIG_TOP_FRONT_LEFT				= 0x00001000,
-	AUDIO_CHANNEL_CONFIG_TOP_FRONT_CENTER			= 0x00002000,
-	AUDIO_CHANNEL_CONFIG_TOP_FRONT_RIGHT			= 0x00004000,
-	AUDIO_CHANNEL_CONFIG_TOP_BACK_LEFT 				= 0x00008000,
-	AUDIO_CHANNEL_CONFIG_TOP_BACK_CENTER			= 0x00010000,
-	AUDIO_CHANNEL_CONFIG_TOP_BACK_RIGHT				= 0x00020000,
-	AUDIO_CHANNEL_CONFIG_TOP_FRONT_LEFT_OF_CENTER	= 0x00040000,
-	AUDIO_CHANNEL_CONFIG_TOP_FRONT_RIGHT_OF_CENTER	= 0x00080000,
-	AUDIO_CHANNEL_CONFIG_LEFT_LOW_FRQ_EFFECTS		= 0x00100000,
-	AUDIO_CHANNEL_CONFIG_RIGHT_LOW_FRQ_EFFECTS		= 0x00200000,
-	AUDIO_CHANNEL_CONFIG_TOP_SIDE_LEFT				= 0x00400000,
-	AUDIO_CHANNEL_CONFIG_TOP_SIDE_RIGHT				= 0x00800000,
-	AUDIO_CHANNEL_CONFIG_BOTTOM_CENTER				= 0x01000000,
-	AUDIO_CHANNEL_CONFIG_BACK_LEFT_OF_CENTER		= 0x02000000,
-	AUDIO_CHANNEL_CONFIG_BACK_RIGHT_OF_CENTER		= 0x04000000,
-	AUDIO_CHANNEL_CONFIG_RAW_DATA					= 0x80000000,
-} audio_channel_config_t;
+  /// Audio Class-Audio Channel Configuration UAC2
+  typedef enum
+  {
+    AUDIO_CHANNEL_CONFIG_NON_PREDEFINED 			= 0x00000000,
+    AUDIO_CHANNEL_CONFIG_FRONT_LEFT 				= 0x00000001,
+    AUDIO_CHANNEL_CONFIG_FRONT_RIGHT 				= 0x00000002,
+    AUDIO_CHANNEL_CONFIG_FRONT_CENTER 				= 0x00000004,
+    AUDIO_CHANNEL_CONFIG_LOW_FRQ_EFFECTS 			= 0x00000008,
+    AUDIO_CHANNEL_CONFIG_BACK_LEFT 					= 0x00000010,
+    AUDIO_CHANNEL_CONFIG_BACK_RIGHT 				= 0x00000020,
+    AUDIO_CHANNEL_CONFIG_FRONT_LEFT_OF_CENTER 		= 0x00000040,
+    AUDIO_CHANNEL_CONFIG_FRONT_RIGHT_OF_CENTER 		= 0x00000080,
+    AUDIO_CHANNEL_CONFIG_BACK_CENTER 				= 0x00000100,
+    AUDIO_CHANNEL_CONFIG_SIDE_LEFT 					= 0x00000200,
+    AUDIO_CHANNEL_CONFIG_SIDE_RIGHT 				= 0x00000400,
+    AUDIO_CHANNEL_CONFIG_TOP_CENTER 				= 0x00000800,
+    AUDIO_CHANNEL_CONFIG_TOP_FRONT_LEFT				= 0x00001000,
+    AUDIO_CHANNEL_CONFIG_TOP_FRONT_CENTER			= 0x00002000,
+    AUDIO_CHANNEL_CONFIG_TOP_FRONT_RIGHT			= 0x00004000,
+    AUDIO_CHANNEL_CONFIG_TOP_BACK_LEFT 				= 0x00008000,
+    AUDIO_CHANNEL_CONFIG_TOP_BACK_CENTER			= 0x00010000,
+    AUDIO_CHANNEL_CONFIG_TOP_BACK_RIGHT				= 0x00020000,
+    AUDIO_CHANNEL_CONFIG_TOP_FRONT_LEFT_OF_CENTER	= 0x00040000,
+    AUDIO_CHANNEL_CONFIG_TOP_FRONT_RIGHT_OF_CENTER	= 0x00080000,
+    AUDIO_CHANNEL_CONFIG_LEFT_LOW_FRQ_EFFECTS		= 0x00100000,
+    AUDIO_CHANNEL_CONFIG_RIGHT_LOW_FRQ_EFFECTS		= 0x00200000,
+    AUDIO_CHANNEL_CONFIG_TOP_SIDE_LEFT				= 0x00400000,
+    AUDIO_CHANNEL_CONFIG_TOP_SIDE_RIGHT				= 0x00800000,
+    AUDIO_CHANNEL_CONFIG_BOTTOM_CENTER				= 0x01000000,
+    AUDIO_CHANNEL_CONFIG_BACK_LEFT_OF_CENTER		= 0x02000000,
+    AUDIO_CHANNEL_CONFIG_BACK_RIGHT_OF_CENTER		= 0x04000000,
+    AUDIO_CHANNEL_CONFIG_RAW_DATA					= 0x80000000,
+  } audio_channel_config_t;
 
-/// AUDIO Channel Cluster Descriptor (4.1)
-typedef struct TU_ATTR_PACKED {
-	uint8_t 				bNrChannels; 		///< Number of channels currently connected.
-	audio_channel_config_t 	bmChannelConfig; 	///< Bitmap according to 'audio_channel_config_t' with a 1 set if channel is connected and 0 else. In case channels are non-predefined ignore them here (see UAC2 specification 4.1 Audio Channel Cluster Descriptor.
-	uint8_t 				iChannelNames; 		///< Index of a string descriptor, describing the name of the first inserted channel with a non-predefined spatial location.
-} audio_desc_channel_cluster_t;
+  /// AUDIO Channel Cluster Descriptor (4.1)
+  typedef struct TU_ATTR_PACKED {
+    uint8_t 				bNrChannels; 		///< Number of channels currently connected.
+    audio_channel_config_t 	bmChannelConfig; 	///< Bitmap according to 'audio_channel_config_t' with a 1 set if channel is connected and 0 else. In case channels are non-predefined ignore them here (see UAC2 specification 4.1 Audio Channel Cluster Descriptor.
+    uint8_t 				iChannelNames; 		///< Index of a string descriptor, describing the name of the first inserted channel with a non-predefined spatial location.
+  } audio_desc_channel_cluster_t;
 
-/// AUDIO Class-Specific AC Interface Header Descriptor (4.7.2)
-typedef struct TU_ATTR_PACKED
-{
-	uint8_t bLength            ; ///< Size of this descriptor in bytes: 9.
-	uint8_t bDescriptorType    ; ///< Descriptor Type. Value: TUSB_DESC_CS_INTERFACE.
-	uint8_t bDescriptorSubType ; ///< Descriptor SubType. Value: AUDIO_CS_AC_INTERFACE_HEADER.
-	uint16_t bcdADC            ; ///< Audio Device Class Specification Release Number in Binary-Coded Decimal. Value: U16_TO_U8S_LE(0x0200).
-	uint8_t bCategory 		 ; ///< Constant, indicating the primary use of this audio function, as intended by the manufacturer. See: audio_function_t.
-	uint16_t wTotalLength      ; ///< Total number of bytes returned for the class-specific AudioControl interface descriptor. Includes the combined length of this descriptor header and all Clock Source, Unit and Terminal descriptors.
-	uint8_t bmControls 		 ; ///< See: audio_cs_ac_interface_control_pos_t.
-} audio_desc_cs_ac_interface_t;
+  /// AUDIO Class-Specific AC Interface Header Descriptor (4.7.2)
+  typedef struct TU_ATTR_PACKED
+  {
+    uint8_t bLength            ; ///< Size of this descriptor in bytes: 9.
+    uint8_t bDescriptorType    ; ///< Descriptor Type. Value: TUSB_DESC_CS_INTERFACE.
+    uint8_t bDescriptorSubType ; ///< Descriptor SubType. Value: AUDIO_CS_AC_INTERFACE_HEADER.
+    uint16_t bcdADC            ; ///< Audio Device Class Specification Release Number in Binary-Coded Decimal. Value: U16_TO_U8S_LE(0x0200).
+    uint8_t bCategory 		 ; ///< Constant, indicating the primary use of this audio function, as intended by the manufacturer. See: audio_function_t.
+    uint16_t wTotalLength      ; ///< Total number of bytes returned for the class-specific AudioControl interface descriptor. Includes the combined length of this descriptor header and all Clock Source, Unit and Terminal descriptors.
+    uint8_t bmControls 		 ; ///< See: audio_cs_ac_interface_control_pos_t.
+  } audio_desc_cs_ac_interface_t;
 
-/// AUDIO Clock Source Descriptor (4.7.2.1)
-typedef struct TU_ATTR_PACKED
-{
-	uint8_t bLength            ; ///< Size of this descriptor in bytes: 8.
-	uint8_t bDescriptorType    ; ///< Descriptor Type. Value: TUSB_DESC_CS_INTERFACE.
-	uint8_t bDescriptorSubType ; ///< Descriptor SubType. Value: AUDIO_CS_AC_INTERFACE_CLOCK_SOURCE.
-	uint8_t bClockID 		 	 ; ///< Constant uniquely identifying the Clock Source Entity within the audio function. This value is used in all requests to address this Entity.
-	uint8_t bmAttributes 		 ; ///< See: audio_clock_source_attribute_t.
-	uint8_t bmControls 		 ; ///< See: audio_clock_source_control_pos_t.
-	uint8_t bAssocTerminal	 ; ///< Terminal ID of the Terminal that is associated with this Clock Source.
-	uint8_t iClockSource	 	 ; ///< Index of a string descriptor, describing the Clock Source Entity.
-} audio_desc_clock_source_t;
+  /// AUDIO Clock Source Descriptor (4.7.2.1)
+  typedef struct TU_ATTR_PACKED
+  {
+    uint8_t bLength            ; ///< Size of this descriptor in bytes: 8.
+    uint8_t bDescriptorType    ; ///< Descriptor Type. Value: TUSB_DESC_CS_INTERFACE.
+    uint8_t bDescriptorSubType ; ///< Descriptor SubType. Value: AUDIO_CS_AC_INTERFACE_CLOCK_SOURCE.
+    uint8_t bClockID 		 	 ; ///< Constant uniquely identifying the Clock Source Entity within the audio function. This value is used in all requests to address this Entity.
+    uint8_t bmAttributes 		 ; ///< See: audio_clock_source_attribute_t.
+    uint8_t bmControls 		 ; ///< See: audio_clock_source_control_pos_t.
+    uint8_t bAssocTerminal	 ; ///< Terminal ID of the Terminal that is associated with this Clock Source.
+    uint8_t iClockSource	 	 ; ///< Index of a string descriptor, describing the Clock Source Entity.
+  } audio_desc_clock_source_t;
 
-/// AUDIO Clock Selector Descriptor (4.7.2.2) for ONE pin
-typedef struct TU_ATTR_PACKED
-{
-	uint8_t bLength            ; ///< Size of this descriptor, in bytes: 7+p.
-	uint8_t bDescriptorType    ; ///< Descriptor Type. Value: TUSB_DESC_CS_INTERFACE.
-	uint8_t bDescriptorSubType ; ///< Descriptor SubType. Value: AUDIO_CS_AC_INTERFACE_CLOCK_SELECTOR.
-	uint8_t bClockID 		 	 ; ///< Constant uniquely identifying the Clock Selector Entity within the audio function. This value is used in all requests to address this Entity.
-	uint8_t bNrInPins 		 ; ///< Number of Input Pins of this Unit: p = 1 thus bNrInPins = 1.
-	uint8_t baCSourceID 		 ; ///< ID of the Clock Entity to which the first Clock Input Pin of this Clock Selector Entity is connected..
-	uint8_t bmControls 		 ; ///< See: audio_clock_selector_control_pos_t.
-	uint8_t iClockSource	 	 ; ///< Index of a string descriptor, describing the Clock Selector Entity.
-} audio_desc_clock_selector_t;
+  /// AUDIO Clock Selector Descriptor (4.7.2.2) for ONE pin
+  typedef struct TU_ATTR_PACKED
+  {
+    uint8_t bLength            ; ///< Size of this descriptor, in bytes: 7+p.
+    uint8_t bDescriptorType    ; ///< Descriptor Type. Value: TUSB_DESC_CS_INTERFACE.
+    uint8_t bDescriptorSubType ; ///< Descriptor SubType. Value: AUDIO_CS_AC_INTERFACE_CLOCK_SELECTOR.
+    uint8_t bClockID 		 	 ; ///< Constant uniquely identifying the Clock Selector Entity within the audio function. This value is used in all requests to address this Entity.
+    uint8_t bNrInPins 		 ; ///< Number of Input Pins of this Unit: p = 1 thus bNrInPins = 1.
+    uint8_t baCSourceID 		 ; ///< ID of the Clock Entity to which the first Clock Input Pin of this Clock Selector Entity is connected..
+    uint8_t bmControls 		 ; ///< See: audio_clock_selector_control_pos_t.
+    uint8_t iClockSource	 	 ; ///< Index of a string descriptor, describing the Clock Selector Entity.
+  } audio_desc_clock_selector_t;
 
-/// AUDIO Clock Selector Descriptor (4.7.2.2) for multiple pins
+  /// AUDIO Clock Selector Descriptor (4.7.2.2) for multiple pins
 #define audio_desc_clock_selector_n_t(source_num) \
-		struct TU_ATTR_PACKED {         \
-	uint8_t bLength            	; \
-	uint8_t bDescriptorType    	; \
-	uint8_t bDescriptorSubType 	; \
-	uint8_t bClockID 		 	; \
-	uint8_t bNrInPins 		 	; \
-	struct TU_ATTR_PACKED {    	  \
-		uint8_t baSourceID		; \
-	} sourceID[source_num]		; \
-	uint8_t bmControls			; \
-	uint8_t iClockSource		; \
+    struct TU_ATTR_PACKED {         \
+  uint8_t bLength            	; \
+  uint8_t bDescriptorType    	; \
+  uint8_t bDescriptorSubType 	; \
+  uint8_t bClockID 		 	; \
+  uint8_t bNrInPins 		 	; \
+  struct TU_ATTR_PACKED {    	  \
+    uint8_t baSourceID		; \
+  } sourceID[source_num]		; \
+  uint8_t bmControls			; \
+  uint8_t iClockSource		; \
 }
 
-/// AUDIO Clock Multiplier Descriptor (4.7.2.3)
-typedef struct TU_ATTR_PACKED
-{
-	uint8_t bLength            ; ///< Size of this descriptor, in bytes: 7.
-	uint8_t bDescriptorType    ; ///< Descriptor Type. Value: TUSB_DESC_CS_INTERFACE.
-	uint8_t bDescriptorSubType ; ///< Descriptor SubType. Value: AUDIO_CS_AC_INTERFACE_CLOCK_MULTIPLIER.
-	uint8_t bClockID 		 	 ; ///< Constant uniquely identifying the Clock Multiplier Entity within the audio function. This value is used in all requests to address this Entity.
-	uint8_t bCSourceID 		 ; ///< ID of the Clock Entity to which the last Clock Input Pin of this Clock Selector Entity is connected.
-	uint8_t bmControls 		 ; ///< See: audio_clock_multiplier_control_pos_t.
-	uint8_t iClockSource	 	 ; ///< Index of a string descriptor, describing the Clock Multiplier Entity.
-} audio_desc_clock_multiplier_t;
+  /// AUDIO Clock Multiplier Descriptor (4.7.2.3)
+  typedef struct TU_ATTR_PACKED
+  {
+    uint8_t bLength            ; ///< Size of this descriptor, in bytes: 7.
+    uint8_t bDescriptorType    ; ///< Descriptor Type. Value: TUSB_DESC_CS_INTERFACE.
+    uint8_t bDescriptorSubType ; ///< Descriptor SubType. Value: AUDIO_CS_AC_INTERFACE_CLOCK_MULTIPLIER.
+    uint8_t bClockID 		 	 ; ///< Constant uniquely identifying the Clock Multiplier Entity within the audio function. This value is used in all requests to address this Entity.
+    uint8_t bCSourceID 		 ; ///< ID of the Clock Entity to which the last Clock Input Pin of this Clock Selector Entity is connected.
+    uint8_t bmControls 		 ; ///< See: audio_clock_multiplier_control_pos_t.
+    uint8_t iClockSource	 	 ; ///< Index of a string descriptor, describing the Clock Multiplier Entity.
+  } audio_desc_clock_multiplier_t;
 
-/// AUDIO Input Terminal Descriptor(4.7.2.4)
-typedef struct TU_ATTR_PACKED
-{
-	uint8_t bLength            ; ///< Size of this descriptor, in bytes: 17.
-	uint8_t bDescriptorType    ; ///< Descriptor Type. Value: TUSB_DESC_CS_INTERFACE.
-	uint8_t bDescriptorSubType ; ///< Descriptor SubType. Value: AUDIO_CS_AC_INTERFACE_INPUT_TERMINAL.
-	uint16_t wTerminalType 	 ; ///< Constant characterizing the type of Terminal. See: audio_terminal_type_t for USB streaming and audio_terminal_input_type_t for other input types.
-	uint8_t bAssocTerminal	 ; ///< ID of the Output Terminal to which this Input Terminal is associated.
-	uint8_t bCSourceID 		 ; ///< ID of the Clock Entity to which this Input Terminal is connected.
-	uint8_t bNrChannels	 	 ; ///< Number of logical output channels in the Terminal’s output audio channel cluster.
-	uint32_t bmChannelConfig	 ; ///< Describes the spatial location of the logical channels. See:audio_channel_config_t.
-	uint16_t bmControls	 	 ; ///< See: audio_terminal_input_control_pos_t.
-	uint8_t iTerminal	 	 	 ; ///< Index of a string descriptor, describing the Input Terminal.
-} audio_desc_input_terminal_t;
+  /// AUDIO Input Terminal Descriptor(4.7.2.4)
+  typedef struct TU_ATTR_PACKED
+  {
+    uint8_t bLength            ; ///< Size of this descriptor, in bytes: 17.
+    uint8_t bDescriptorType    ; ///< Descriptor Type. Value: TUSB_DESC_CS_INTERFACE.
+    uint8_t bDescriptorSubType ; ///< Descriptor SubType. Value: AUDIO_CS_AC_INTERFACE_INPUT_TERMINAL.
+    uint16_t wTerminalType 	 ; ///< Constant characterizing the type of Terminal. See: audio_terminal_type_t for USB streaming and audio_terminal_input_type_t for other input types.
+    uint8_t bAssocTerminal	 ; ///< ID of the Output Terminal to which this Input Terminal is associated.
+    uint8_t bCSourceID 		 ; ///< ID of the Clock Entity to which this Input Terminal is connected.
+    uint8_t bNrChannels	 	 ; ///< Number of logical output channels in the Terminal’s output audio channel cluster.
+    uint32_t bmChannelConfig	 ; ///< Describes the spatial location of the logical channels. See:audio_channel_config_t.
+    uint16_t bmControls	 	 ; ///< See: audio_terminal_input_control_pos_t.
+    uint8_t iTerminal	 	 	 ; ///< Index of a string descriptor, describing the Input Terminal.
+  } audio_desc_input_terminal_t;
 
-/// AUDIO Output Terminal Descriptor(4.7.2.5)
-typedef struct TU_ATTR_PACKED
-{
-	uint8_t bLength            ; ///< Size of this descriptor, in bytes: 12.
-	uint8_t bDescriptorType    ; ///< Descriptor Type. Value: TUSB_DESC_CS_INTERFACE.
-	uint8_t bDescriptorSubType ; ///< Descriptor SubType. Value: AUDIO_CS_AC_INTERFACE_OUTPUT_TERMINAL.
-	uint8_t bTerminalID 	 	 ; ///< Constant uniquely identifying the Terminal within the audio function. This value is used in all requests to address this Terminal.
-	uint16_t wTerminalType	 ; ///< Constant characterizing the type of Terminal. See: audio_terminal_type_t for USB streaming and audio_terminal_output_type_t for other output types.
-	uint8_t bAssocTerminal 	 ; ///< Constant, identifying the Input Terminal to which this Output Terminal is associated.
-	uint8_t bSourceID		 	 ; ///< ID of the Unit or Terminal to which this Terminal is connected.
-	uint8_t bCSourceID	 	 ; ///< ID of the Clock Entity to which this Output Terminal is connected.
-	uint16_t bmControls	 	 ; ///< See: audio_terminal_output_type_t.
-	uint8_t iTerminal	 	 	 ; ///< Index of a string descriptor, describing the Output Terminal.
-} audio_desc_output_terminal_t;
+  /// AUDIO Output Terminal Descriptor(4.7.2.5)
+  typedef struct TU_ATTR_PACKED
+  {
+    uint8_t bLength            ; ///< Size of this descriptor, in bytes: 12.
+    uint8_t bDescriptorType    ; ///< Descriptor Type. Value: TUSB_DESC_CS_INTERFACE.
+    uint8_t bDescriptorSubType ; ///< Descriptor SubType. Value: AUDIO_CS_AC_INTERFACE_OUTPUT_TERMINAL.
+    uint8_t bTerminalID 	 	 ; ///< Constant uniquely identifying the Terminal within the audio function. This value is used in all requests to address this Terminal.
+    uint16_t wTerminalType	 ; ///< Constant characterizing the type of Terminal. See: audio_terminal_type_t for USB streaming and audio_terminal_output_type_t for other output types.
+    uint8_t bAssocTerminal 	 ; ///< Constant, identifying the Input Terminal to which this Output Terminal is associated.
+    uint8_t bSourceID		 	 ; ///< ID of the Unit or Terminal to which this Terminal is connected.
+    uint8_t bCSourceID	 	 ; ///< ID of the Clock Entity to which this Output Terminal is connected.
+    uint16_t bmControls	 	 ; ///< See: audio_terminal_output_type_t.
+    uint8_t iTerminal	 	 	 ; ///< Index of a string descriptor, describing the Output Terminal.
+  } audio_desc_output_terminal_t;
 
-/// AUDIO Feature Unit Descriptor(4.7.2.8) for ONE channel
-typedef struct TU_ATTR_PACKED
-{
-	uint8_t bLength            ; ///< Size of this descriptor, in bytes: 14.
-	uint8_t bDescriptorType    ; ///< Descriptor Type. Value: TUSB_DESC_CS_INTERFACE.
-	uint8_t bDescriptorSubType ; ///< Descriptor SubType. Value: AUDIO_CS_AC_INTERFACE_FEATURE_UNIT.
-	uint8_t bUnitID    	 	 ; ///< Constant uniquely identifying the Unit within the audio function. This value is used in all requests to address this Unit.
-	uint8_t bSourceID	 		 ; ///< ID of the Unit or Terminal to which this Feature Unit is connected.
-	struct TU_ATTR_PACKED {
-		uint32_t bmaControls	 ; ///< See: audio_feature_unit_control_pos_t. Controls0 is master channel 0 (always present) and Controls1 is logical channel 1.
-	} controls[2] 		     ;
-	uint8_t iTerminal	 	 	 ; ///< Index of a string descriptor, describing this Feature Unit.
-} audio_desc_feature_unit_t;
+  /// AUDIO Feature Unit Descriptor(4.7.2.8) for ONE channel
+  typedef struct TU_ATTR_PACKED
+  {
+    uint8_t bLength            ; ///< Size of this descriptor, in bytes: 14.
+    uint8_t bDescriptorType    ; ///< Descriptor Type. Value: TUSB_DESC_CS_INTERFACE.
+    uint8_t bDescriptorSubType ; ///< Descriptor SubType. Value: AUDIO_CS_AC_INTERFACE_FEATURE_UNIT.
+    uint8_t bUnitID    	 	 ; ///< Constant uniquely identifying the Unit within the audio function. This value is used in all requests to address this Unit.
+    uint8_t bSourceID	 		 ; ///< ID of the Unit or Terminal to which this Feature Unit is connected.
+    struct TU_ATTR_PACKED {
+      uint32_t bmaControls	 ; ///< See: audio_feature_unit_control_pos_t. Controls0 is master channel 0 (always present) and Controls1 is logical channel 1.
+    } controls[2] 		     ;
+    uint8_t iTerminal	 	 	 ; ///< Index of a string descriptor, describing this Feature Unit.
+  } audio_desc_feature_unit_t;
 
-/// AUDIO Feature Unit Descriptor(4.7.2.8) for multiple channels
+  /// AUDIO Feature Unit Descriptor(4.7.2.8) for multiple channels
 #define audio_desc_feature_unit_n_t(ch_num) \
-		struct TU_ATTR_PACKED {         \
-	uint8_t bLength            	; /* 6+(ch_num+1)*4 */\
-		uint8_t bDescriptorType    	; \
-		uint8_t bDescriptorSubType 	; \
-		uint8_t bUnitID 		 	; \
-		uint8_t bSourceID 		 	; \
-		struct TU_ATTR_PACKED {    	  \
-			uint32_t bmaControls	; \
-		} controls[ch_num+1]		; \
-		uint8_t iTerminal			; \
+    struct TU_ATTR_PACKED {         \
+  uint8_t bLength            	; /* 6+(ch_num+1)*4 */\
+    uint8_t bDescriptorType    	; \
+    uint8_t bDescriptorSubType 	; \
+    uint8_t bUnitID 		 	; \
+    uint8_t bSourceID 		 	; \
+    struct TU_ATTR_PACKED {    	  \
+      uint32_t bmaControls	; \
+    } controls[ch_num+1]		; \
+    uint8_t iTerminal			; \
 }
 
 /// AUDIO Class-Specific AS Interface Descriptor(4.9.2)
 typedef struct TU_ATTR_PACKED
 {
-	uint8_t bLength            ; ///< Size of this descriptor, in bytes: 16.
-	uint8_t bDescriptorType    ; ///< Descriptor Type. Value: TUSB_DESC_CS_INTERFACE.
-	uint8_t bDescriptorSubType ; ///< Descriptor SubType. Value: AUDIO_CS_AS_INTERFACE_AS_GENERAL.
-	uint8_t bTerminalLink	 	 ; ///< The Terminal ID of the Terminal to which this interface is connected.
-	uint8_t bmControls	 	 ; ///< See: audio_cs_as_interface_control_pos_t.
-	uint8_t bFormatType 	 	 ; ///< Constant identifying the Format Type the AudioStreaming interface is using. See: audio_format_type_t.
-	uint32_t bmFormats	 	 ; ///< The Audio Data Format(s) that can be used to communicate with this interface.See: audio_data_format_type_I_t.
-	uint8_t bNrChannels	 	 ; ///< Number of physical channels in the AS Interface audio channel cluster.
-	uint32_t bmChannelConfig	 ; ///< Describes the spatial location of the physical channels. See: audio_channel_config_t.
-	uint8_t iChannelNames	 	 ; ///< Index of a string descriptor, describing the name of the first physical channel.
+  uint8_t bLength            ; ///< Size of this descriptor, in bytes: 16.
+  uint8_t bDescriptorType    ; ///< Descriptor Type. Value: TUSB_DESC_CS_INTERFACE.
+  uint8_t bDescriptorSubType ; ///< Descriptor SubType. Value: AUDIO_CS_AS_INTERFACE_AS_GENERAL.
+  uint8_t bTerminalLink	 	 ; ///< The Terminal ID of the Terminal to which this interface is connected.
+  uint8_t bmControls	 	 ; ///< See: audio_cs_as_interface_control_pos_t.
+  uint8_t bFormatType 	 	 ; ///< Constant identifying the Format Type the AudioStreaming interface is using. See: audio_format_type_t.
+  uint32_t bmFormats	 	 ; ///< The Audio Data Format(s) that can be used to communicate with this interface.See: audio_data_format_type_I_t.
+  uint8_t bNrChannels	 	 ; ///< Number of physical channels in the AS Interface audio channel cluster.
+  uint32_t bmChannelConfig	 ; ///< Describes the spatial location of the physical channels. See: audio_channel_config_t.
+  uint8_t iChannelNames	 	 ; ///< Index of a string descriptor, describing the name of the first physical channel.
 } audio_desc_cs_as_interface_t;
 
 /// AUDIO Type I Format Type Descriptor(2.3.1.6 - Audio Formats)
 typedef struct TU_ATTR_PACKED
 {
-	uint8_t bLength            ; ///< Size of this descriptor, in bytes: 6.
-	uint8_t bDescriptorType    ; ///< Descriptor Type. Value: TUSB_DESC_CS_INTERFACE.
-	uint8_t bDescriptorSubType ; ///< Descriptor SubType. Value: AUDIO_CS_AS_INTERFACE_FORMAT_TYPE.
-	uint8_t bFormatType	 	 ; ///< Constant identifying the Format Type the AudioStreaming interface is using. Value: AUDIO_FORMAT_TYPE_I.
-	uint8_t bSubslotSize	 	 ; ///< The number of bytes occupied by one audio subslot. Can be 1, 2, 3 or 4.
-	uint8_t bBitResolution 	 ; ///< The number of effectively used bits from the available bits in an audio subslot.
+  uint8_t bLength            ; ///< Size of this descriptor, in bytes: 6.
+  uint8_t bDescriptorType    ; ///< Descriptor Type. Value: TUSB_DESC_CS_INTERFACE.
+  uint8_t bDescriptorSubType ; ///< Descriptor SubType. Value: AUDIO_CS_AS_INTERFACE_FORMAT_TYPE.
+  uint8_t bFormatType	 	 ; ///< Constant identifying the Format Type the AudioStreaming interface is using. Value: AUDIO_FORMAT_TYPE_I.
+  uint8_t bSubslotSize	 	 ; ///< The number of bytes occupied by one audio subslot. Can be 1, 2, 3 or 4.
+  uint8_t bBitResolution 	 ; ///< The number of effectively used bits from the available bits in an audio subslot.
 } audio_desc_type_I_format_t;
 
 /// AUDIO Class-Specific AS Isochronous Audio Data Endpoint Descriptor(4.10.1.2)
 typedef struct TU_ATTR_PACKED
 {
-	uint8_t bLength            ; ///< Size of this descriptor, in bytes: 8.
-	uint8_t bDescriptorType    ; ///< Descriptor Type. Value: TUSB_DESC_CS_ENDPOINT.
-	uint8_t bDescriptorSubType ; ///< Descriptor SubType. Value: AUDIO_CS_EP_SUBTYPE_GENERAL.
-	uint8_t bmAttributes	 	 ; ///< See: audio_cs_as_iso_data_ep_attribute_t.
-	uint8_t bmControls	 	 ; ///< See: audio_cs_as_iso_data_ep_control_pos_t.
-	uint8_t bLockDelayUnits 	 ; ///< Indicates the units used for the wLockDelay field. See: audio_cs_as_iso_data_ep_lock_delay_unit_t.
-	uint16_t wLockDelay 		 ; ///< Indicates the time it takes this endpoint to reliably lock its internal clock recovery circuitry. Units used depend on the value of the bLockDelayUnits field.
+  uint8_t bLength            ; ///< Size of this descriptor, in bytes: 8.
+  uint8_t bDescriptorType    ; ///< Descriptor Type. Value: TUSB_DESC_CS_ENDPOINT.
+  uint8_t bDescriptorSubType ; ///< Descriptor SubType. Value: AUDIO_CS_EP_SUBTYPE_GENERAL.
+  uint8_t bmAttributes	 	 ; ///< See: audio_cs_as_iso_data_ep_attribute_t.
+  uint8_t bmControls	 	 ; ///< See: audio_cs_as_iso_data_ep_control_pos_t.
+  uint8_t bLockDelayUnits 	 ; ///< Indicates the units used for the wLockDelay field. See: audio_cs_as_iso_data_ep_lock_delay_unit_t.
+  uint16_t wLockDelay 		 ; ///< Indicates the time it takes this endpoint to reliably lock its internal clock recovery circuitry. Units used depend on the value of the bLockDelayUnits field.
 } audio_desc_cs_as_iso_data_ep_t;
 
 //// 5.2.3 Control Request Parameter Block Layout
@@ -825,91 +826,91 @@ typedef struct TU_ATTR_PACKED
 // 5.2.3.1 1-byte Control CUR Parameter Block
 typedef struct TU_ATTR_PACKED
 {
-	int8_t bCur            	; 	///< The setting for the CUR attribute of the addressed Control
+  int8_t bCur            	; 	///< The setting for the CUR attribute of the addressed Control
 } audio_control_cur_1_t;
 
 // 5.2.3.2 2-byte Control CUR Parameter Block
 typedef struct TU_ATTR_PACKED
 {
-	int16_t bCur            	;	///< The setting for the CUR attribute of the addressed Control
+  int16_t bCur            	;	///< The setting for the CUR attribute of the addressed Control
 } audio_control_cur_2_t;
 
 // 5.2.3.3 4-byte Control CUR Parameter Block
 typedef struct TU_ATTR_PACKED
 {
-	int32_t bCur            	;	///< The setting for the CUR attribute of the addressed Control
+  int32_t bCur            	;	///< The setting for the CUR attribute of the addressed Control
 } audio_control_cur_4_t;
 
 // Use the following ONLY for RECEIVED data - compiler does not know how many subranges are defined! Use the one below for predefined lengths - or if you know what you are doing do what you like
 // 5.2.3.1 1-byte Control RANGE Parameter Block
 typedef struct TU_ATTR_PACKED {
-	uint16_t wNumSubRanges;
-	struct TU_ATTR_PACKED {
-		int8_t bMin			; /*The setting for the MIN attribute of the nth subrange of the addressed Control*/
-		int8_t bMax			; /*The setting for the MAX attribute of the nth subrange of the addressed Control*/
-		uint8_t bRes			; /*The setting for the RES attribute of the nth subrange of the addressed Control*/
-	} subrange[]				;
+  uint16_t wNumSubRanges;
+  struct TU_ATTR_PACKED {
+    int8_t bMin			; /*The setting for the MIN attribute of the nth subrange of the addressed Control*/
+    int8_t bMax			; /*The setting for the MAX attribute of the nth subrange of the addressed Control*/
+    uint8_t bRes			; /*The setting for the RES attribute of the nth subrange of the addressed Control*/
+  } subrange[]				;
 } audio_control_range_1_t;
 
 // 5.2.3.2 2-byte Control RANGE Parameter Block
 typedef struct TU_ATTR_PACKED {
-	uint16_t wNumSubRanges;
-	struct TU_ATTR_PACKED {
-		int16_t bMin			; /*The setting for the MIN attribute of the nth subrange of the addressed Control*/
-		int16_t bMax			; /*The setting for the MAX attribute of the nth subrange of the addressed Control*/
-		uint16_t bRes			; /*The setting for the RES attribute of the nth subrange of the addressed Control*/
-	} subrange[]				;
+  uint16_t wNumSubRanges;
+  struct TU_ATTR_PACKED {
+    int16_t bMin			; /*The setting for the MIN attribute of the nth subrange of the addressed Control*/
+    int16_t bMax			; /*The setting for the MAX attribute of the nth subrange of the addressed Control*/
+    uint16_t bRes			; /*The setting for the RES attribute of the nth subrange of the addressed Control*/
+  } subrange[]				;
 } audio_control_range_2_t;
 
 // 5.2.3.3 4-byte Control RANGE Parameter Block
 typedef struct TU_ATTR_PACKED {
-	uint16_t wNumSubRanges;
-	struct TU_ATTR_PACKED {
-		int32_t bMin			; /*The setting for the MIN attribute of the nth subrange of the addressed Control*/
-		int32_t bMax			; /*The setting for the MAX attribute of the nth subrange of the addressed Control*/
-		uint32_t bRes			; /*The setting for the RES attribute of the nth subrange of the addressed Control*/
-	} subrange[]				;
+  uint16_t wNumSubRanges;
+  struct TU_ATTR_PACKED {
+    int32_t bMin			; /*The setting for the MIN attribute of the nth subrange of the addressed Control*/
+    int32_t bMax			; /*The setting for the MAX attribute of the nth subrange of the addressed Control*/
+    uint32_t bRes			; /*The setting for the RES attribute of the nth subrange of the addressed Control*/
+  } subrange[]				;
 } audio_control_range_4_t;
 
 // 5.2.3.1 1-byte Control RANGE Parameter Block
 #define audio_control_range_1_n_t(numSubRanges) \
-		struct TU_ATTR_PACKED {         		\
-	uint16_t wNumSubRanges; 					\
-	struct TU_ATTR_PACKED {    	  				\
-			int8_t bMin				; /*The setting for the MIN attribute of the nth subrange of the addressed Control*/\
-		int8_t bMax					; /*The setting for the MAX attribute of the nth subrange of the addressed Control*/\
-		uint8_t bRes				; /*The setting for the RES attribute of the nth subrange of the addressed Control*/\
-		} subrange[numSubRanges]	; \
-}
+    struct TU_ATTR_PACKED {         		\
+  uint16_t wNumSubRanges; 					\
+  struct TU_ATTR_PACKED {    	  				\
+      int8_t bMin				; /*The setting for the MIN attribute of the nth subrange of the addressed Control*/\
+    int8_t bMax					; /*The setting for the MAX attribute of the nth subrange of the addressed Control*/\
+    uint8_t bRes				; /*The setting for the RES attribute of the nth subrange of the addressed Control*/\
+    } subrange[numSubRanges]	; \
+  }
 
-		// 5.2.3.2 2-byte Control RANGE Parameter Block
+    // 5.2.3.2 2-byte Control RANGE Parameter Block
 #define audio_control_range_2_n_t(numSubRanges) \
-		struct TU_ATTR_PACKED {         		\
-	uint16_t wNumSubRanges; 					\
-	struct TU_ATTR_PACKED {    	  				\
-			int16_t bMin			; /*The setting for the MIN attribute of the nth subrange of the addressed Control*/\
-		int16_t bMax			; /*The setting for the MAX attribute of the nth subrange of the addressed Control*/\
-		uint16_t bRes			; /*The setting for the RES attribute of the nth subrange of the addressed Control*/\
-		} subrange[numSubRanges]		; \
-	}
+    struct TU_ATTR_PACKED {         		\
+  uint16_t wNumSubRanges; 					\
+  struct TU_ATTR_PACKED {    	  				\
+      int16_t bMin			; /*The setting for the MIN attribute of the nth subrange of the addressed Control*/\
+    int16_t bMax			; /*The setting for the MAX attribute of the nth subrange of the addressed Control*/\
+    uint16_t bRes			; /*The setting for the RES attribute of the nth subrange of the addressed Control*/\
+    } subrange[numSubRanges]		; \
+  }
 
-		// 5.2.3.3 4-byte Control RANGE Parameter Block
+    // 5.2.3.3 4-byte Control RANGE Parameter Block
 #define audio_control_range_4_n_t(numSubRanges) \
-		struct TU_ATTR_PACKED {         		\
-	uint16_t wNumSubRanges; 					\
-	struct TU_ATTR_PACKED {    	  				\
-			int32_t bMin			; /*The setting for the MIN attribute of the nth subrange of the addressed Control*/\
-		int32_t bMax			; /*The setting for the MAX attribute of the nth subrange of the addressed Control*/\
-		uint32_t bRes			; /*The setting for the RES attribute of the nth subrange of the addressed Control*/\
-		} subrange[numSubRanges]		; \
-	}
+    struct TU_ATTR_PACKED {         		\
+  uint16_t wNumSubRanges; 					\
+  struct TU_ATTR_PACKED {    	  				\
+      int32_t bMin			; /*The setting for the MIN attribute of the nth subrange of the addressed Control*/\
+    int32_t bMax			; /*The setting for the MAX attribute of the nth subrange of the addressed Control*/\
+    uint32_t bRes			; /*The setting for the RES attribute of the nth subrange of the addressed Control*/\
+    } subrange[numSubRanges]		; \
+  }
 
-		/** @} */
+    /** @} */
 
 #ifdef __cplusplus
-	}
+  }
 #endif
 
 #endif
 
-	/** @} */
+  /** @} */
diff --git a/src/class/audio/audio_device.c b/src/class/audio/audio_device.c
index 2e3625825..129aed481 100644
--- a/src/class/audio/audio_device.c
+++ b/src/class/audio/audio_device.c
@@ -384,7 +384,8 @@ static bool audio_tx_done_cb(uint8_t rhport, audiod_interface_t* audio, uint16_t
   {
     case AUDIO_FORMAT_TYPE_UNDEFINED:
       // INDIVIDUAL ENCODING PROCEDURE REQUIRED HERE!
-      asm("nop");
+      TU_LOG2("  Desired CFG_TUD_AUDIO_FORMAT encoding not implemented!\r\n");
+      TU_BREAKPOINT();
       break;
 
     case AUDIO_FORMAT_TYPE_I:
@@ -402,19 +403,21 @@ static bool audio_tx_done_cb(uint8_t rhport, audiod_interface_t* audio, uint16_t
 
 	default:
 	  // YOUR ENCODING AND SENDING IS REQUIRED HERE!
-	  asm("nop");
+	  TU_LOG2("  Desired CFG_TUD_AUDIO_FORMAT_TYPE_I_TX encoding not implemented!\r\n");
+	  TU_BREAKPOINT();
 	  break;
       }
       break;
 
 	default:
 	  // Desired CFG_TUD_AUDIO_FORMAT_TYPE_TX not implemented!
-	  asm("nop");
+	  TU_LOG2("  Desired CFG_TUD_AUDIO_FORMAT_TYPE_TX not implemented!\r\n");
+	  TU_BREAKPOINT();
 	  break;
   }
 
   // Call a weak callback here - a possibility for user to get informed TX was completed
-  TU_VERIFY(tud_audio_tx_done_cb(rhport, n_bytes_copied));
+  if (tud_audio_tx_done_cb) TU_VERIFY(tud_audio_tx_done_cb(rhport, n_bytes_copied));
   return true;
 }
 
@@ -497,7 +500,7 @@ static uint16_t audio_fb_done_cb(uint8_t rhport, audiod_interface_t* audio)
   // Here we need to return the feedback value
 #error RETURN YOUR FEEDBACK VALUE HERE!
 
-  TU_VERIFY(tud_audio_fb_done_cb(rhport));
+  if (tud_audio_fb_done_cb) TU_VERIFY(tud_audio_fb_done_cb(rhport));
   return 0;
 }
 
@@ -522,57 +525,12 @@ static bool audio_int_ctr_done_cb(uint8_t rhport, audiod_interface_t* audio, uin
 
   *n_bytes_copied = cnt;
 
-  TU_VERIFY(tud_audio_int_ctr_done_cb(rhport, n_bytes_copied));
+  if (tud_audio_int_ctr_done_cb) TU_VERIFY(tud_audio_int_ctr_done_cb(rhport, n_bytes_copied));
 
   return true;
 }
 #endif
 
-// Callback functions
-// Currently the return value has to effect so far. The return value finally is discarded in tud_task(void) in usbd.c - we just incorporate that for later use
-
-#if CFG_TUD_AUDIO_EPSIZE_IN
-TU_ATTR_WEAK bool tud_audio_tx_done_cb(uint8_t rhport, uint16_t * n_bytes_copied)
-{
-  (void) rhport;
-  (void) n_bytes_copied;
-
-  /* NOTE: This function should not be modified, when the callback is needed,
-           the tud_audio_tx_done_cb could be implemented in the user file
-   */
-
-  return true;
-}
-#endif
-
-#if CFG_TUD_AUDIO_EPSIZE_OUT && CFG_TUD_AUDIO_ENABLE_FEEDBACK_EP
-TU_ATTR_WEAK bool tud_audio_fb_done_cb(uint8_t rhport)
-{
-  (void) rhport;
-
-  /* NOTE: This function should not be modified, when the callback is needed,
-           the tud_audio_fb_done_cb could be implemented in the user file
-   */
-
-  return true;
-}
-#endif
-
-#if CFG_TUD_AUDIO_INT_CTR_EPSIZE_IN
-TU_ATTR_WEAK bool tud_audio_int_ctr_done_cb(uint8_t rhport, uint16_t * n_bytes_copied)
-{
-  (void) rhport;
-  (void) n_bytes_copied;
-
-  /* NOTE: This function should not be modified, when the callback is needed,
-	           the tud_audio_int_ctr_done_cb could be implemented in the user file
-   */
-
-  return true;
-}
-
-#endif
-
 //--------------------------------------------------------------------+
 // USBD Driver API
 //--------------------------------------------------------------------+
@@ -755,6 +713,8 @@ static bool audiod_set_interface(uint8_t rhport, tusb_control_request_t const *
   }
 #endif
 
+  // Save current alternative interface setting
+  _audiod_itf[idxDriver].altSetting[idxItf] = alt;
 
   // Open new EP if necessary - EPs are only to be closed or opened for AS interfaces - Look for AS interface with correct alternate interface
   // Get pointer at end
@@ -778,8 +738,16 @@ static bool audiod_set_interface(uint8_t rhport, tusb_control_request_t const *
 #if CFG_TUD_AUDIO_EPSIZE_IN > 0
 	  if (tu_edpt_dir(ep_addr) == TUSB_DIR_IN && ((tusb_desc_endpoint_t const *) p_desc)->bmAttributes.usage == 0x00) 	// Check if usage is data EP
 	  {
+	    // Save address
 	    _audiod_itf[idxDriver].ep_in = ep_addr;
 	    _audiod_itf[idxDriver].ep_in_as_intf_num = itf;
+
+	    // HERE WE WOULD NEED TO SCHEDULE OUR FIRST TRANSMIT, HOWEVER, WE ALSO WOULD FIRST NEED TO ENABLE SAMPLING AT ALL - HOW TO HANDLE THIS?
+	    // Invoke callback - fill something in the FIFO here for now
+	    if (tud_audio_set_itf_cb) TU_VERIFY(tud_audio_set_itf_cb(rhport, p_request));
+
+	    uint16_t n_bytes_copied;
+	    TU_VERIFY(audio_tx_done_cb(rhport, &_audiod_itf[idxDriver], &n_bytes_copied));
 	  }
 #endif
 
@@ -791,6 +759,9 @@ static bool audiod_set_interface(uint8_t rhport, tusb_control_request_t const *
 	    _audiod_itf[idxDriver].ep_out = ep_addr;
 	    _audiod_itf[idxDriver].ep_out_as_intf_num = itf;
 
+	    // Invoke callback
+	    if (tud_audio_set_itf_cb) TU_VERIFY(tud_audio_set_itf_cb(rhport, p_request));
+
 	    // Prepare for incoming data
 	    TU_ASSERT(usbd_edpt_xfer(rhport, ep_addr, _audiod_itf[idxDriver].epout_buf, CFG_TUD_AUDIO_EPSIZE_OUT), false);
 	  }
@@ -799,6 +770,9 @@ static bool audiod_set_interface(uint8_t rhport, tusb_control_request_t const *
 	  if (tu_edpt_dir(ep_addr) == TUSB_DIR_IN && ((tusb_desc_endpoint_t const *) p_desc)->bmAttributes.usage == 0x10) 	// Check if usage is implicit data feedback
 	  {
 	    _audiod_itf[idxDriver].ep_fb = ep_addr;
+
+	    // Invoke callback
+	    if (tud_audio_set_itf_cb) TU_VERIFY(tud_audio_set_itf_cb(rhport, p_request));
 	  }
 #endif
 
@@ -818,20 +792,6 @@ static bool audiod_set_interface(uint8_t rhport, tusb_control_request_t const *
     p_desc = tu_desc_next(p_desc);
   }
 
-//  // Check for nothing found - we can rely on this since EP descriptors are never the last descriptors, there are always also class specific EP descriptors following!
-//  TU_VERIFY(p_desc < p_desc_end);
-
-  // Save current alternative interface setting
-  _audiod_itf[idxDriver].altSetting[idxItf] = alt;
-
-  // Invoke callback
-  if (tud_audio_set_itf_cb)
-  {
-    if (!tud_audio_set_itf_cb(rhport, p_request)) return false;
-  }
-
-  // Start sending or receiving?
-
   tud_control_status(rhport, p_request);
 
   return true;
diff --git a/src/class/audio/audio_device.h b/src/class/audio/audio_device.h
index 9766eb5f9..b745ceb09 100644
--- a/src/class/audio/audio_device.h
+++ b/src/class/audio/audio_device.h
@@ -1,7 +1,8 @@
 /* 
  * The MIT License (MIT)
  *
- * Copyright (c) 2020 Ha Thach (tinyusb.org) and Reinhard Panhuber
+ * Copyright (c) 2020 Ha Thach (tinyusb.org)
+ * Copyright (c) 2020 Reinhard Panhuber
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -217,15 +218,15 @@ bool tud_audio_buffer_and_schedule_control_xfer(uint8_t rhport, tusb_control_req
 //--------------------------------------------------------------------+
 
 #if CFG_TUD_AUDIO_EPSIZE_IN
-bool tud_audio_tx_done_cb(uint8_t rhport, uint16_t * n_bytes_copied);
+TU_ATTR_WEAK bool tud_audio_tx_done_cb(uint8_t rhport, uint16_t * n_bytes_copied);
 #endif
 
 #if CFG_TUD_AUDIO_EPSIZE_OUT
-bool tud_audio_rx_done_cb(uint8_t rhport, uint8_t * buffer, uint16_t bufsize);
+TU_ATTR_WEAK bool tud_audio_rx_done_cb(uint8_t rhport, uint8_t * buffer, uint16_t bufsize);
 #endif
 
 #if CFG_TUD_AUDIO_EPSIZE_OUT > 0 && CFG_TUD_AUDIO_ENABLE_FEEDBACK_EP
-bool tud_audio_fb_done_cb(uint8_t rhport);
+TU_ATTR_WEAK bool tud_audio_fb_done_cb(uint8_t rhport);
 #endif
 
 #if CFG_TUD_AUDIO_INT_CTR_EPSIZE_IN
diff --git a/src/portable/st/synopsys/dcd_synopsys.c b/src/portable/st/synopsys/dcd_synopsys.c
index 2d42dd43b..c188bb485 100644
--- a/src/portable/st/synopsys/dcd_synopsys.c
+++ b/src/portable/st/synopsys/dcd_synopsys.c
@@ -4,6 +4,7 @@
  * Copyright (c) 2018 Scott Shawcroft, 2019 William D. Jones for Adafruit Industries
  * Copyright (c) 2019 Ha Thach (tinyusb.org)
  * Copyright (c) 2020 Jan Duempelmann
+ * Copyright (c) 2020 Reinhard Panhuber
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal