Add UAC2 speaker with feedback example.

9 files changed, 1118 insertions, 0 deletions

diff --git a/examples/device/uac2_speaker_fb/CMakeLists.txt b/examples/device/uac2_speaker_fb/CMakeLists.txt
new file mode 100644
index 000000000..e92a57148
--- /dev/null
+++ b/examples/device/uac2_speaker_fb/CMakeLists.txt
@@ -0,0 +1,33 @@
+cmake_minimum_required(VERSION 3.17)
+
+include(${CMAKE_CURRENT_SOURCE_DIR}/../../../hw/bsp/family_support.cmake)
+
+# gets PROJECT name for the example (e.g. <BOARD>-<DIR_NAME>)
+family_get_project_name(PROJECT ${CMAKE_CURRENT_LIST_DIR})
+
+project(${PROJECT} C CXX ASM)
+
+# Checks this example is valid for the family and initializes the project
+family_initialize_project(${PROJECT} ${CMAKE_CURRENT_LIST_DIR})
+
+# Espressif has its own cmake build system
+if(FAMILY STREQUAL "espressif")
+  return()
+endif()
+
+add_executable(${PROJECT})
+
+# Example source
+target_sources(${PROJECT} PUBLIC
+        ${CMAKE_CURRENT_SOURCE_DIR}/src/main.c
+        ${CMAKE_CURRENT_SOURCE_DIR}/src/usb_descriptors.c
+        )
+
+# Example include
+target_include_directories(${PROJECT} PUBLIC
+        ${CMAKE_CURRENT_SOURCE_DIR}/src
+        )
+
+# Configure compilation flags and libraries for the example without RTOS.
+# See the corresponding function in hw/bsp/FAMILY/family.cmake for details.
+family_configure_device_example(${PROJECT} noos)
diff --git a/examples/device/uac2_speaker_fb/Makefile b/examples/device/uac2_speaker_fb/Makefile
new file mode 100644
index 000000000..7fa475da5
--- /dev/null
+++ b/examples/device/uac2_speaker_fb/Makefile
@@ -0,0 +1,11 @@
+include ../../build_system/make/make.mk
+
+INC += \
+  src \
+  $(TOP)/hw \
+
+# Example source
+EXAMPLE_SOURCE += $(wildcard src/*.c)
+SRC_C += $(addprefix $(CURRENT_PATH)/, $(EXAMPLE_SOURCE))
+
+include ../../build_system/make/rules.mk
diff --git a/examples/device/uac2_speaker_fb/skip.txt b/examples/device/uac2_speaker_fb/skip.txt
new file mode 100644
index 000000000..234f1ebed
--- /dev/null
+++ b/examples/device/uac2_speaker_fb/skip.txt
@@ -0,0 +1,8 @@
+mcu:LPC11UXX
+mcu:LPC13XX
+mcu:NUC121
+mcu:SAMD11
+mcu:SAME5X
+mcu:SAMG
+board:stm32l052dap52
+family:broadcom_64bit
diff --git a/examples/device/uac2_speaker_fb/src/audio_debug.py b/examples/device/uac2_speaker_fb/src/audio_debug.py
new file mode 100644
index 000000000..182d6ca89
--- /dev/null
+++ b/examples/device/uac2_speaker_fb/src/audio_debug.py
@@ -0,0 +1,63 @@
+# Install python3 HID package https://pypi.org/project/hid/
+import hid
+from ctypes import *
+import matplotlib.pyplot as plt
+import matplotlib.animation as animation
+
+# Example must be compiled with CFG_AUDIO_DEBUG=1
+VID = 0xcafe
+PID = 0x4014
+
+CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_RX = 2
+
+class audio_debug_info_t (Structure):
+    _fields_ = [("sample_rate", c_uint32),
+                ("alt_settings", c_uint8),
+                ("mute", (CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_RX + 1) * c_int8),
+                ("volume", (CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_RX + 1) * c_int16),
+                ("fifo_size", c_uint16),
+                ("fifo_count", c_uint16),
+                ("fifo_count_avg", c_uint16)
+                ]
+
+dev = hid.Device(VID, PID)
+
+if dev:
+    # Create figure for plotting
+    fig = plt.figure()
+    ax = fig.add_subplot(1, 1, 1)
+    fifo_avg = []
+    fifo_cnt = []
+    # This function is called periodically from FuncAnimation
+    def animate(i):
+        info = None
+        for i in range(30):
+            str_in = dev.read(64, 10)
+            if str_in:
+                info = audio_debug_info_t.from_buffer_copy(str_in)
+
+                global fifo_avg
+                global fifo_cnt
+                fifo_avg.append(info.fifo_count_avg)
+                fifo_cnt.append(info.fifo_count)
+
+        # Limit to 1000 items
+        fifo_avg = fifo_avg[-1000:]
+        fifo_cnt = fifo_cnt[-1000:]
+
+        if info is not None:
+            # Draw x and y lists
+            ax.clear()
+            ax.plot(fifo_cnt, label='FIFO count')
+            ax.plot(fifo_avg, label='FIFO average')
+            ax.legend()
+            ax.set_ylim(bottom=0, top=info.fifo_size)
+
+            # Format plot
+            plt.title('FIFO information')
+            plt.grid()
+
+            print(f'Sample rate:{info.sample_rate} | Alt settings:{info.alt_settings} | Volume:{info.volume[:]}')
+
+    ani = animation.FuncAnimation(fig, animate, interval=10)
+    plt.show()
diff --git a/examples/device/uac2_speaker_fb/src/common_types.h b/examples/device/uac2_speaker_fb/src/common_types.h
new file mode 100644
index 000000000..174e26671
--- /dev/null
+++ b/examples/device/uac2_speaker_fb/src/common_types.h
@@ -0,0 +1,52 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2023 HiFiPhile
+ *
+ * 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 _COMMON_TYPES_H_
+#define _COMMON_TYPES_H_
+
+enum
+{
+  ITF_NUM_AUDIO_CONTROL = 0,
+  ITF_NUM_AUDIO_STREAMING,
+#if CFG_AUDIO_DEBUG
+  ITF_NUM_DEBUG,
+#endif
+  ITF_NUM_TOTAL
+};
+
+#if CFG_AUDIO_DEBUG
+typedef struct
+  {
+    uint32_t sample_rate;
+    uint8_t alt_settings;
+    int8_t mute[CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_RX + 1];
+    int16_t volume[CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_RX + 1];
+    uint16_t fifo_size;
+    uint16_t fifo_count;
+    uint16_t fifo_count_avg;
+  } audio_debug_info_t;
+#endif
+
+#endif
diff --git a/examples/device/uac2_speaker_fb/src/main.c b/examples/device/uac2_speaker_fb/src/main.c
new file mode 100644
index 000000000..6d0e7acff
--- /dev/null
+++ b/examples/device/uac2_speaker_fb/src/main.c
@@ -0,0 +1,478 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Jerzy Kasenberg
+ *
+ * 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 <stdio.h>
+#include <string.h>
+
+#include "bsp/board_api.h"
+#include "tusb.h"
+#include "usb_descriptors.h"
+#include "common_types.h"
+
+//--------------------------------------------------------------------+
+// MACRO CONSTANT TYPEDEF PROTOTYPES
+//--------------------------------------------------------------------+
+
+// List of supported sample rates
+#if defined(__RX__)
+  const uint32_t sample_rates[] = {44100, 48000};
+#else
+  const uint32_t sample_rates[] = {44100, 48000, 88200, 96000};
+#endif
+
+uint32_t current_sample_rate  = 44100;
+
+#define N_SAMPLE_RATES  TU_ARRAY_SIZE(sample_rates)
+
+/* Blink pattern
+ * - 25 ms   : streaming data
+ * - 250 ms  : device not mounted
+ * - 1000 ms : device mounted
+ * - 2500 ms : device is suspended
+ */
+enum
+{
+  BLINK_STREAMING = 25,
+  BLINK_NOT_MOUNTED = 250,
+  BLINK_MOUNTED = 1000,
+  BLINK_SUSPENDED = 2500,
+};
+
+enum
+{
+  VOLUME_CTRL_0_DB = 0,
+  VOLUME_CTRL_10_DB = 2560,
+  VOLUME_CTRL_20_DB = 5120,
+  VOLUME_CTRL_30_DB = 7680,
+  VOLUME_CTRL_40_DB = 10240,
+  VOLUME_CTRL_50_DB = 12800,
+  VOLUME_CTRL_60_DB = 15360,
+  VOLUME_CTRL_70_DB = 17920,
+  VOLUME_CTRL_80_DB = 20480,
+  VOLUME_CTRL_90_DB = 23040,
+  VOLUME_CTRL_100_DB = 25600,
+  VOLUME_CTRL_SILENCE = 0x8000,
+};
+
+static uint32_t blink_interval_ms = BLINK_NOT_MOUNTED;
+
+// Audio controls
+// Current states
+int8_t mute[CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_RX + 1];       // +1 for master channel 0
+int16_t volume[CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_RX + 1];    // +1 for master channel 0
+
+// Buffer for speaker data
+uint16_t i2s_dummy_buffer[CFG_TUD_AUDIO_FUNC_1_EP_OUT_SW_BUF_SZ/2];
+
+void led_blinking_task(void);
+void audio_task(void);
+
+#if CFG_AUDIO_DEBUG
+void audio_debug_task(void);
+uint8_t current_alt_settings;
+#endif
+
+/*------------- MAIN -------------*/
+int main(void)
+{
+  board_init();
+
+  // init device stack on configured roothub port
+  tud_init(BOARD_TUD_RHPORT);
+
+  if (board_init_after_tusb) {
+    board_init_after_tusb();
+  }
+
+  TU_LOG1("Speaker running\r\n");
+
+  while (1)
+  {
+    tud_task(); // TinyUSB device task
+    led_blinking_task();
+#if CFG_AUDIO_DEBUG
+    audio_debug_task();
+#endif
+    audio_task();
+  }
+}
+
+//--------------------------------------------------------------------+
+// 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 = tud_mounted() ? BLINK_MOUNTED : BLINK_NOT_MOUNTED;
+}
+
+//--------------------------------------------------------------------+
+// Application Callback API Implementations
+//--------------------------------------------------------------------+
+
+// Helper for clock get requests
+static bool tud_audio_clock_get_request(uint8_t rhport, audio_control_request_t const *request)
+{
+  TU_ASSERT(request->bEntityID == UAC2_ENTITY_CLOCK);
+
+  if (request->bControlSelector == AUDIO_CS_CTRL_SAM_FREQ)
+  {
+    if (request->bRequest == AUDIO_CS_REQ_CUR)
+    {
+      TU_LOG1("Clock get current freq %lu\r\n", current_sample_rate);
+
+      audio_control_cur_4_t curf = { (int32_t) tu_htole32(current_sample_rate) };
+      return tud_audio_buffer_and_schedule_control_xfer(rhport, (tusb_control_request_t const *)request, &curf, sizeof(curf));
+    }
+    else if (request->bRequest == AUDIO_CS_REQ_RANGE)
+    {
+      audio_control_range_4_n_t(N_SAMPLE_RATES) rangef =
+      {
+        .wNumSubRanges = tu_htole16(N_SAMPLE_RATES)
+      };
+      TU_LOG1("Clock get %d freq ranges\r\n", N_SAMPLE_RATES);
+      for(uint8_t i = 0; i < N_SAMPLE_RATES; i++)
+      {
+        rangef.subrange[i].bMin = (int32_t) sample_rates[i];
+        rangef.subrange[i].bMax = (int32_t) sample_rates[i];
+        rangef.subrange[i].bRes = 0;
+        TU_LOG1("Range %d (%d, %d, %d)\r\n", i, (int)rangef.subrange[i].bMin, (int)rangef.subrange[i].bMax, (int)rangef.subrange[i].bRes);
+      }
+
+      return tud_audio_buffer_and_schedule_control_xfer(rhport, (tusb_control_request_t const *)request, &rangef, sizeof(rangef));
+    }
+  }
+  else if (request->bControlSelector == AUDIO_CS_CTRL_CLK_VALID &&
+           request->bRequest == AUDIO_CS_REQ_CUR)
+  {
+    audio_control_cur_1_t cur_valid = { .bCur = 1 };
+    TU_LOG1("Clock get is valid %u\r\n", cur_valid.bCur);
+    return tud_audio_buffer_and_schedule_control_xfer(rhport, (tusb_control_request_t const *)request, &cur_valid, sizeof(cur_valid));
+  }
+  TU_LOG1("Clock get request not supported, entity = %u, selector = %u, request = %u\r\n",
+          request->bEntityID, request->bControlSelector, request->bRequest);
+  return false;
+}
+
+// Helper for clock set requests
+static bool tud_audio_clock_set_request(uint8_t rhport, audio_control_request_t const *request, uint8_t const *buf)
+{
+  (void)rhport;
+
+  TU_ASSERT(request->bEntityID == UAC2_ENTITY_CLOCK);
+  TU_VERIFY(request->bRequest == AUDIO_CS_REQ_CUR);
+
+  if (request->bControlSelector == AUDIO_CS_CTRL_SAM_FREQ)
+  {
+    TU_VERIFY(request->wLength == sizeof(audio_control_cur_4_t));
+
+    current_sample_rate = (uint32_t) ((audio_control_cur_4_t const *)buf)->bCur;
+
+    TU_LOG1("Clock set current freq: %ld\r\n", current_sample_rate);
+
+    return true;
+  }
+  else
+  {
+    TU_LOG1("Clock set request not supported, entity = %u, selector = %u, request = %u\r\n",
+            request->bEntityID, request->bControlSelector, request->bRequest);
+    return false;
+  }
+}
+
+// Helper for feature unit get requests
+static bool tud_audio_feature_unit_get_request(uint8_t rhport, audio_control_request_t const *request)
+{
+  TU_ASSERT(request->bEntityID == UAC2_ENTITY_FEATURE_UNIT);
+
+  if (request->bControlSelector == AUDIO_FU_CTRL_MUTE && request->bRequest == AUDIO_CS_REQ_CUR)
+  {
+    audio_control_cur_1_t mute1 = { .bCur = mute[request->bChannelNumber] };
+    TU_LOG1("Get channel %u mute %d\r\n", request->bChannelNumber, mute1.bCur);
+    return tud_audio_buffer_and_schedule_control_xfer(rhport, (tusb_control_request_t const *)request, &mute1, sizeof(mute1));
+  }
+  else if (UAC2_ENTITY_FEATURE_UNIT && request->bControlSelector == AUDIO_FU_CTRL_VOLUME)
+  {
+    if (request->bRequest == AUDIO_CS_REQ_RANGE)
+    {
+      audio_control_range_2_n_t(1) range_vol = {
+        .wNumSubRanges = tu_htole16(1),
+        .subrange[0] = { .bMin = tu_htole16(-VOLUME_CTRL_50_DB), tu_htole16(VOLUME_CTRL_0_DB), tu_htole16(256) }
+      };
+      TU_LOG1("Get channel %u volume range (%d, %d, %u) dB\r\n", request->bChannelNumber,
+              range_vol.subrange[0].bMin / 256, range_vol.subrange[0].bMax / 256, range_vol.subrange[0].bRes / 256);
+      return tud_audio_buffer_and_schedule_control_xfer(rhport, (tusb_control_request_t const *)request, &range_vol, sizeof(range_vol));
+    }
+    else if (request->bRequest == AUDIO_CS_REQ_CUR)
+    {
+      audio_control_cur_2_t cur_vol = { .bCur = tu_htole16(volume[request->bChannelNumber]) };
+      TU_LOG1("Get channel %u volume %d dB\r\n", request->bChannelNumber, cur_vol.bCur / 256);
+      return tud_audio_buffer_and_schedule_control_xfer(rhport, (tusb_control_request_t const *)request, &cur_vol, sizeof(cur_vol));
+    }
+  }
+  TU_LOG1("Feature unit get request not supported, entity = %u, selector = %u, request = %u\r\n",
+          request->bEntityID, request->bControlSelector, request->bRequest);
+
+  return false;
+}
+
+// Helper for feature unit set requests
+static bool tud_audio_feature_unit_set_request(uint8_t rhport, audio_control_request_t const *request, uint8_t const *buf)
+{
+  (void)rhport;
+
+  TU_ASSERT(request->bEntityID == UAC2_ENTITY_FEATURE_UNIT);
+  TU_VERIFY(request->bRequest == AUDIO_CS_REQ_CUR);
+
+  if (request->bControlSelector == AUDIO_FU_CTRL_MUTE)
+  {
+    TU_VERIFY(request->wLength == sizeof(audio_control_cur_1_t));
+
+    mute[request->bChannelNumber] = ((audio_control_cur_1_t const *)buf)->bCur;
+
+    TU_LOG1("Set channel %d Mute: %d\r\n", request->bChannelNumber, mute[request->bChannelNumber]);
+
+    return true;
+  }
+  else if (request->bControlSelector == AUDIO_FU_CTRL_VOLUME)
+  {
+    TU_VERIFY(request->wLength == sizeof(audio_control_cur_2_t));
+
+    volume[request->bChannelNumber] = ((audio_control_cur_2_t const *)buf)->bCur;
+
+    TU_LOG1("Set channel %d volume: %d dB\r\n", request->bChannelNumber, volume[request->bChannelNumber] / 256);
+
+    return true;
+  }
+  else
+  {
+    TU_LOG1("Feature unit set request not supported, entity = %u, selector = %u, request = %u\r\n",
+            request->bEntityID, request->bControlSelector, request->bRequest);
+    return false;
+  }
+}
+
+// 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)
+{
+  audio_control_request_t const *request = (audio_control_request_t const *)p_request;
+
+  if (request->bEntityID == UAC2_ENTITY_CLOCK)
+    return tud_audio_clock_get_request(rhport, request);
+  if (request->bEntityID == UAC2_ENTITY_FEATURE_UNIT)
+    return tud_audio_feature_unit_get_request(rhport, request);
+  else
+  {
+    TU_LOG1("Get request not handled, entity = %d, selector = %d, request = %d\r\n",
+            request->bEntityID, request->bControlSelector, request->bRequest);
+  }
+  return false;
+}
+
+// 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 *buf)
+{
+  audio_control_request_t const *request = (audio_control_request_t const *)p_request;
+
+  if (request->bEntityID == UAC2_ENTITY_FEATURE_UNIT)
+    return tud_audio_feature_unit_set_request(rhport, request, buf);
+  if (request->bEntityID == UAC2_ENTITY_CLOCK)
+    return tud_audio_clock_set_request(rhport, request, buf);
+  TU_LOG1("Set request not handled, entity = %d, selector = %d, request = %d\r\n",
+          request->bEntityID, request->bControlSelector, request->bRequest);
+
+  return false;
+}
+
+bool tud_audio_set_itf_close_EP_cb(uint8_t rhport, tusb_control_request_t const * p_request)
+{
+  (void)rhport;
+
+  uint8_t const itf = tu_u16_low(tu_le16toh(p_request->wIndex));
+  uint8_t const alt = tu_u16_low(tu_le16toh(p_request->wValue));
+
+  if (ITF_NUM_AUDIO_STREAMING == itf && alt == 0)
+      blink_interval_ms = BLINK_MOUNTED;
+
+  return true;
+}
+
+bool tud_audio_set_itf_cb(uint8_t rhport, tusb_control_request_t const * p_request)
+{
+  (void)rhport;
+  uint8_t const itf = tu_u16_low(tu_le16toh(p_request->wIndex));
+  uint8_t const alt = tu_u16_low(tu_le16toh(p_request->wValue));
+
+  TU_LOG2("Set interface %d alt %d\r\n", itf, alt);
+  if (ITF_NUM_AUDIO_STREAMING == itf && alt != 0)
+      blink_interval_ms = BLINK_STREAMING;
+
+#if CFG_AUDIO_DEBUG
+  current_alt_settings = alt;
+#endif
+
+  return true;
+}
+
+void tud_audio_feedback_params_cb(uint8_t func_id, uint8_t alt_itf, audio_feedback_params_t* feedback_param)
+{
+  (void)func_id;
+  (void)alt_itf;
+  // Set feedback method to fifo counting
+  feedback_param->method = AUDIO_FEEDBACK_METHOD_FIFO_COUNT;
+  feedback_param->sample_freq = current_sample_rate;
+}
+
+//--------------------------------------------------------------------+
+// AUDIO Task
+//--------------------------------------------------------------------+
+
+void audio_task(void)
+{
+  // Replace audio_task() with your I2S transmit callback.
+  // Here we simulate a callback called every 1ms.
+  static uint32_t start_ms = 0;
+  uint32_t curr_ms = board_millis();
+  if ( start_ms == curr_ms ) return; // not enough time
+  start_ms = curr_ms;
+
+  uint16_t length = current_sample_rate/1000 * CFG_TUD_AUDIO_FUNC_1_N_BYTES_PER_SAMPLE_RX * CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_RX;
+
+  if (current_sample_rate == 44100 && (curr_ms % 10 == 0))
+  {
+    // Take one more sample every 10 cycles, to have a average reading speed of 44.1
+    // This correction is not needed in real world cases
+    length += CFG_TUD_AUDIO_FUNC_1_N_BYTES_PER_SAMPLE_RX * CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_RX;
+  } else
+  if (current_sample_rate == 88200 && (curr_ms % 5 == 0))
+  {
+    // Take one more sample every 5 cycles, to have a average reading speed of 88.2
+    // This correction is not needed in real world cases
+    length += CFG_TUD_AUDIO_FUNC_1_N_BYTES_PER_SAMPLE_RX * CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_RX;
+  }
+
+  tud_audio_read(i2s_dummy_buffer, length);
+}
+
+//--------------------------------------------------------------------+
+// 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;
+  start_ms += blink_interval_ms;
+
+  board_led_write(led_state);
+  led_state = 1 - led_state;
+}
+
+#if CFG_AUDIO_DEBUG
+//--------------------------------------------------------------------+
+// HID interface for audio debug
+//--------------------------------------------------------------------+
+
+// Every 1ms, we will sent 1 debug information report
+void audio_debug_task(void)
+{
+  static uint32_t start_ms = 0;
+  uint32_t curr_ms = board_millis();
+  if ( start_ms == curr_ms ) return; // not enough time
+  start_ms = curr_ms;
+
+  uint16_t fifo_count = tud_audio_available();
+  static uint32_t fifo_count_avg;
+
+  // Same averaging method used in UAC2 class
+  fifo_count_avg = (uint32_t)(((uint64_t)fifo_count_avg * 63  + ((uint32_t)fifo_count << 16)) >> 6);
+
+  audio_debug_info_t debug_info;
+  debug_info.sample_rate    = current_sample_rate;
+  debug_info.alt_settings   = current_alt_settings;
+  debug_info.fifo_size      = CFG_TUD_AUDIO_FUNC_1_EP_OUT_SW_BUF_SZ;
+  debug_info.fifo_count     = fifo_count;
+  debug_info.fifo_count_avg = fifo_count_avg >> 16;
+  for (int i = 0; i < CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_RX + 1; i++)
+  {
+    debug_info.mute[i] = mute[i];
+    debug_info.volume[i] = volume[i];
+  }
+
+  if(tud_hid_ready())
+    tud_hid_report(0, &debug_info, sizeof(debug_info));
+}
+
+// Invoked when received GET_REPORT control request
+// Unused here
+uint16_t tud_hid_get_report_cb(uint8_t itf, uint8_t report_id, hid_report_type_t report_type, uint8_t* buffer, uint16_t reqlen)
+{
+  // TODO not Implemented
+  (void) itf;
+  (void) report_id;
+  (void) report_type;
+  (void) buffer;
+  (void) reqlen;
+
+  return 0;
+}
+
+// Invoked when received SET_REPORT control request or
+// Unused here
+void tud_hid_set_report_cb(uint8_t itf, uint8_t report_id, hid_report_type_t report_type, uint8_t const* buffer, uint16_t bufsize)
+{
+  // This example doesn't use multiple report and report ID
+  (void) itf;
+  (void) report_id;
+  (void) report_type;
+  (void) buffer;
+  (void) bufsize;
+}
+
+#endif
diff --git a/examples/device/uac2_speaker_fb/src/tusb_config.h b/examples/device/uac2_speaker_fb/src/tusb_config.h
new file mode 100644
index 000000000..497104541
--- /dev/null
+++ b/examples/device/uac2_speaker_fb/src/tusb_config.h
@@ -0,0 +1,157 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Ha Thach (tinyusb.org)
+ * Copyright (c) 2020 Jerzy Kasenberg
+ *
+ * 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
+
+#include "usb_descriptors.h"
+
+//--------------------------------------------------------------------+
+// Board Specific Configuration
+//--------------------------------------------------------------------+
+
+// RHPort number used for device can be defined by board.mk, default to port 0
+#ifndef BOARD_TUD_RHPORT
+#define BOARD_TUD_RHPORT      0
+#endif
+
+// RHPort max operational speed can defined by board.mk
+#ifndef BOARD_TUD_MAX_SPEED
+#define BOARD_TUD_MAX_SPEED   OPT_MODE_DEFAULT_SPEED
+#endif
+
+//--------------------------------------------------------------------
+// Common Configuration
+//--------------------------------------------------------------------
+
+// defined by compiler flags for flexibility
+#ifndef CFG_TUSB_MCU
+#error CFG_TUSB_MCU must be defined
+#endif
+
+#ifndef CFG_TUSB_OS
+#define CFG_TUSB_OS           OPT_OS_NONE
+#endif
+
+// It's recommended to disable debug unless for control requests debugging,
+// as the extra time needed will impact data stream !
+#ifndef CFG_TUSB_DEBUG
+#define CFG_TUSB_DEBUG        0
+#endif
+
+// Enable Device stack
+#define CFG_TUD_ENABLED       1
+
+// Default is max speed that hardware controller could support with on-chip PHY
+#define CFG_TUD_MAX_SPEED     BOARD_TUD_MAX_SPEED
+
+/* 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
+//--------------------------------------------------------------------
+
+// Expose audio class debug information via HID interface
+#ifndef CFG_AUDIO_DEBUG
+#define CFG_AUDIO_DEBUG           1
+#endif
+
+#ifndef CFG_TUD_ENDPOINT0_SIZE
+#define CFG_TUD_ENDPOINT0_SIZE    64
+#endif
+
+#define CFG_TUD_HID_EP_BUFSIZE    64
+
+//------------- CLASS -------------//
+#define CFG_TUD_AUDIO             1
+
+#if CFG_AUDIO_DEBUG
+#define CFG_TUD_HID               1
+#else
+#define CFG_TUD_HID               0
+#endif
+
+#define CFG_TUD_CDC               0
+#define CFG_TUD_MSC               0
+#define CFG_TUD_MIDI              0
+#define CFG_TUD_VENDOR            0
+
+//--------------------------------------------------------------------
+// AUDIO CLASS DRIVER CONFIGURATION
+//--------------------------------------------------------------------
+
+#define CFG_TUD_AUDIO_FUNC_1_DESC_LEN                                TUD_AUDIO_SPEAKER_STEREO_FB_DESC_LEN
+
+// Audio format type I specifications
+#if defined(__RX__)
+#define CFG_TUD_AUDIO_FUNC_1_MAX_SAMPLE_RATE                         48000
+#else
+#define CFG_TUD_AUDIO_FUNC_1_MAX_SAMPLE_RATE                         96000
+#endif
+
+#define CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_RX                           2
+
+// 16bit in 16bit slots
+#define CFG_TUD_AUDIO_FUNC_1_N_BYTES_PER_SAMPLE_RX                   2
+#define CFG_TUD_AUDIO_FUNC_1_RESOLUTION_RX                           16
+
+// 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_ENABLE_EP_OUT                                  1
+
+#define CFG_TUD_AUDIO_FUNC_1_EP_OUT_SZ_MAX        TUD_AUDIO_EP_SIZE(CFG_TUD_AUDIO_FUNC_1_MAX_SAMPLE_RATE, CFG_TUD_AUDIO_FUNC_1_N_BYTES_PER_SAMPLE_RX, CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_RX)
+#define CFG_TUD_AUDIO_FUNC_1_EP_OUT_SW_BUF_SZ     (TUD_OPT_HIGH_SPEED ? 32 : 4) * CFG_TUD_AUDIO_FUNC_1_EP_OUT_SZ_MAX // Example read FIFO every 1ms, so it should be 8 times larger for HS device
+
+// Enable feedback EP
+#define CFG_TUD_AUDIO_ENABLE_FEEDBACK_EP                             1
+
+// 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_FUNC_1_N_AS_INT 	                             1
+
+// Size of control request buffer
+#define CFG_TUD_AUDIO_FUNC_1_CTRL_BUF_SZ	                         64
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _TUSB_CONFIG_H_ */
diff --git a/examples/device/uac2_speaker_fb/src/usb_descriptors.c b/examples/device/uac2_speaker_fb/src/usb_descriptors.c
new file mode 100644
index 000000000..864b689ff
--- /dev/null
+++ b/examples/device/uac2_speaker_fb/src/usb_descriptors.c
@@ -0,0 +1,234 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2023 HiFiPhile
+ *
+ * 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 "bsp/board_api.h"
+#include "tusb.h"
+#include "usb_descriptors.h"
+#include "common_types.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 Audio
+    // 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;
+}
+
+#if CFG_AUDIO_DEBUG
+//--------------------------------------------------------------------+
+// HID Report Descriptor
+//--------------------------------------------------------------------+
+
+uint8_t const desc_hid_report[] =
+{
+  HID_USAGE_PAGE_N ( HID_USAGE_PAGE_VENDOR, 2   ),\
+  HID_USAGE        ( 0x01                       ),\
+  HID_COLLECTION   ( HID_COLLECTION_APPLICATION ),\
+  HID_USAGE       ( 0x02                                   ),\
+  HID_LOGICAL_MIN ( 0x00                                   ),\
+  HID_LOGICAL_MAX_N ( 0xff, 2                              ),\
+  HID_REPORT_SIZE ( 8                                      ),\
+  HID_REPORT_COUNT( sizeof(audio_debug_info_t)             ),\
+  HID_INPUT       ( HID_DATA | HID_VARIABLE | HID_ABSOLUTE ),\
+  HID_COLLECTION_END
+};
+
+// Invoked when received GET HID REPORT DESCRIPTOR
+// Application return pointer to descriptor
+// Descriptor contents must exist long enough for transfer to complete
+uint8_t const * tud_hid_descriptor_report_cb(uint8_t itf)
+{
+  (void) itf;
+  return desc_hid_report;
+}
+#endif
+
+//--------------------------------------------------------------------+
+// Configuration Descriptor
+//--------------------------------------------------------------------+
+
+#if CFG_AUDIO_DEBUG
+  #define CONFIG_TOTAL_LEN    	(TUD_CONFIG_DESC_LEN + TUD_AUDIO_SPEAKER_STEREO_FB_DESC_LEN + TUD_HID_DESC_LEN)
+#else
+  #define CONFIG_TOTAL_LEN    	(TUD_CONFIG_DESC_LEN + TUD_AUDIO_SPEAKER_STEREO_FB_DESC_LEN)
+#endif
+
+#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_FB    0x03
+  #define EPNUM_AUDIO_OUT   0x03
+  #define EPNUM_DEBUG       0x04
+
+#elif CFG_TUSB_MCU == OPT_MCU_NRF5X
+  // ISO endpoints for NRF5x are fixed to 0x08 (0x88)
+  #define EPNUM_AUDIO_FB    0x08
+  #define EPNUM_AUDIO_OUT   0x08
+  #define EPNUM_DEBUG       0x01
+
+#elif CFG_TUSB_MCU == OPT_MCU_SAMG  || CFG_TUSB_MCU ==  OPT_MCU_SAMX7X
+  // SAMG & SAME70 don't support a same endpoint number with different direction IN and OUT
+  //    e.g EP1 OUT & EP1 IN cannot exist together
+  #define EPNUM_AUDIO_FB    0x01
+  #define EPNUM_AUDIO_OUT   0x02
+  #define EPNUM_DEBUG       0x03
+
+#elif CFG_TUSB_MCU == OPT_MCU_FT90X || CFG_TUSB_MCU == OPT_MCU_FT93X
+  // FT9XX doesn't support a same endpoint number with different direction IN and OUT
+  //    e.g EP1 OUT & EP1 IN cannot exist together
+  #define EPNUM_AUDIO_FB    0x01
+  #define EPNUM_AUDIO_OUT   0x02
+  #define EPNUM_DEBUG       0x03
+
+#else
+  #define EPNUM_AUDIO_FB    0x01
+  #define EPNUM_AUDIO_OUT   0x01
+  #define EPNUM_DEBUG       0x02
+#endif
+
+uint8_t const desc_configuration[] =
+{
+    // Config number, interface count, string index, total length, attribute, power in mA
+    TUD_CONFIG_DESCRIPTOR(1, ITF_NUM_TOTAL, 0, CONFIG_TOTAL_LEN, 0x00, 100),
+
+    // Interface number, string index, byte per sample, bit per sample, EP Out, EP size, EP feedback
+    TUD_AUDIO_SPEAKER_STEREO_FB_DESCRIPTOR(0, 4, CFG_TUD_AUDIO_FUNC_1_N_BYTES_PER_SAMPLE_RX, CFG_TUD_AUDIO_FUNC_1_RESOLUTION_RX, EPNUM_AUDIO_OUT, CFG_TUD_AUDIO_FUNC_1_EP_OUT_SZ_MAX, EPNUM_AUDIO_FB | 0x80),
+
+#if CFG_AUDIO_DEBUG
+    // Interface number, string index, protocol, report descriptor len, EP In address, size & polling interval
+    TUD_HID_DESCRIPTOR(ITF_NUM_DEBUG, 0, HID_ITF_PROTOCOL_NONE, sizeof(desc_hid_report), EPNUM_DEBUG | 0x80, CFG_TUD_HID_EP_BUFSIZE, 7)
+#endif
+};
+
+// 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
+//--------------------------------------------------------------------+
+
+// String Descriptor Index
+enum {
+  STRID_LANGID = 0,
+  STRID_MANUFACTURER,
+  STRID_PRODUCT,
+  STRID_SERIAL,
+};
+
+// array of pointer to string descriptors
+char const *string_desc_arr[] =
+{
+  (const char[]) { 0x09, 0x04 },  // 0: is supported language is English (0x0409)
+  "TinyUSB",                      // 1: Manufacturer
+  "TinyUSB Speaker",              // 2: Product
+  NULL,                           // 3: Serials will use unique ID if possible
+  "UAC2 Speaker",                 // 4: Audio Interface
+};
+
+static uint16_t _desc_str[32 + 1];
+
+// 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;
+  size_t chr_count;
+
+  switch ( index ) {
+    case STRID_LANGID:
+      memcpy(&_desc_str[1], string_desc_arr[0], 2);
+      chr_count = 1;
+      break;
+
+    case STRID_SERIAL:
+      chr_count = board_usb_get_serial(_desc_str + 1, 32);
+      break;
+
+    default:
+      // Note: the 0xEE index string is a Microsoft OS 1.0 Descriptors.
+      // https://docs.microsoft.com/en-us/windows-hardware/drivers/usbcon/microsoft-defined-usb-descriptors
+
+      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);
+      size_t const max_count = sizeof(_desc_str) / sizeof(_desc_str[0]) - 1; // -1 for string type
+      if ( chr_count > max_count ) chr_count = max_count;
+
+      // Convert ASCII string into UTF-16
+      for ( size_t i = 0; i < chr_count; i++ ) {
+        _desc_str[1 + i] = str[i];
+      }
+      break;
+  }
+
+  // first byte is length (including header), second byte is string type
+  _desc_str[0] = (uint16_t) ((TUSB_DESC_STRING << 8) | (2 * chr_count + 2));
+
+  return _desc_str;
+}
diff --git a/examples/device/uac2_speaker_fb/src/usb_descriptors.h b/examples/device/uac2_speaker_fb/src/usb_descriptors.h
new file mode 100644
index 000000000..8157f02a0
--- /dev/null
+++ b/examples/device/uac2_speaker_fb/src/usb_descriptors.h
@@ -0,0 +1,82 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2023 HiFiPhile
+ *
+ * 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 _USB_DESCRIPTORS_H_
+#define _USB_DESCRIPTORS_H_
+
+// Defined in TUD_AUDIO_SPEAKER_STEREO_FB_DESCRIPTOR
+#define UAC2_ENTITY_CLOCK               0x04
+#define UAC2_ENTITY_INPUT_TERMINAL      0x01
+#define UAC2_ENTITY_FEATURE_UNIT        0x02
+#define UAC2_ENTITY_OUTPUT_TERMINAL     0x03
+
+#define TUD_AUDIO_SPEAKER_STEREO_FB_DESC_LEN (TUD_AUDIO_DESC_IAD_LEN\
+  + TUD_AUDIO_DESC_STD_AC_LEN\
+  + TUD_AUDIO_DESC_CS_AC_LEN\
+  + TUD_AUDIO_DESC_CLK_SRC_LEN\
+  + TUD_AUDIO_DESC_INPUT_TERM_LEN\
+  + TUD_AUDIO_DESC_OUTPUT_TERM_LEN\
+  + TUD_AUDIO_DESC_FEATURE_UNIT_TWO_CHANNEL_LEN\
+  + TUD_AUDIO_DESC_STD_AS_INT_LEN\
+  + TUD_AUDIO_DESC_STD_AS_INT_LEN\
+  + TUD_AUDIO_DESC_CS_AS_INT_LEN\
+  + TUD_AUDIO_DESC_TYPE_I_FORMAT_LEN\
+  + TUD_AUDIO_DESC_STD_AS_ISO_EP_LEN\
+  + TUD_AUDIO_DESC_CS_AS_ISO_EP_LEN\
+  + TUD_AUDIO_DESC_STD_AS_ISO_FB_EP_LEN)
+
+#define TUD_AUDIO_SPEAKER_STEREO_FB_DESCRIPTOR(_itfnum, _stridx, _nBytesPerSample, _nBitsUsedPerSample, _epout, _epsize, _epfb) \
+  /* Standard Interface Association Descriptor (IAD) */\
+  TUD_AUDIO_DESC_IAD(/*_firstitf*/ _itfnum, /*_nitfs*/ 0x02, /*_stridx*/ 0x00),\
+  /* Standard AC Interface Descriptor(4.7.1) */\
+  TUD_AUDIO_DESC_STD_AC(/*_itfnum*/ _itfnum, /*_nEPs*/ 0x00, /*_stridx*/ _stridx),\
+  /* Class-Specific AC Interface Header Descriptor(4.7.2) */\
+  TUD_AUDIO_DESC_CS_AC(/*_bcdADC*/ 0x0200, /*_category*/ AUDIO_FUNC_DESKTOP_SPEAKER, /*_totallen*/ TUD_AUDIO_DESC_CLK_SRC_LEN+TUD_AUDIO_DESC_INPUT_TERM_LEN+TUD_AUDIO_DESC_OUTPUT_TERM_LEN+TUD_AUDIO_DESC_FEATURE_UNIT_TWO_CHANNEL_LEN, /*_ctrl*/ AUDIO_CS_AS_INTERFACE_CTRL_LATENCY_POS),\
+  /* Clock Source Descriptor(4.7.2.1) */\
+  TUD_AUDIO_DESC_CLK_SRC(/*_clkid*/ 0x04, /*_attr*/ AUDIO_CLOCK_SOURCE_ATT_INT_PRO_CLK, /*_ctrl*/ (AUDIO_CTRL_RW << AUDIO_CLOCK_SOURCE_CTRL_CLK_FRQ_POS), /*_assocTerm*/ 0x01,  /*_stridx*/ 0x00),\
+  /* Input Terminal Descriptor(4.7.2.4) */\
+  TUD_AUDIO_DESC_INPUT_TERM(/*_termid*/ 0x01, /*_termtype*/ AUDIO_TERM_TYPE_USB_STREAMING, /*_assocTerm*/ 0x00, /*_clkid*/ 0x04, /*_nchannelslogical*/ 0x02, /*_channelcfg*/ AUDIO_CHANNEL_CONFIG_NON_PREDEFINED, /*_idxchannelnames*/ 0x00, /*_ctrl*/ 0 * (AUDIO_CTRL_R << AUDIO_IN_TERM_CTRL_CONNECTOR_POS), /*_stridx*/ 0x00),\
+  /* Output Terminal Descriptor(4.7.2.5) */\
+  TUD_AUDIO_DESC_OUTPUT_TERM(/*_termid*/ 0x03, /*_termtype*/ AUDIO_TERM_TYPE_OUT_DESKTOP_SPEAKER, /*_assocTerm*/ 0x01, /*_srcid*/ 0x02, /*_clkid*/ 0x04, /*_ctrl*/ 0x0000, /*_stridx*/ 0x00),\
+  /* Feature Unit Descriptor(4.7.2.8) */\
+  TUD_AUDIO_DESC_FEATURE_UNIT_TWO_CHANNEL(/*_unitid*/ 0x02, /*_srcid*/ 0x01, /*_ctrlch0master*/ AUDIO_CTRL_RW << AUDIO_FEATURE_UNIT_CTRL_MUTE_POS | AUDIO_CTRL_RW << AUDIO_FEATURE_UNIT_CTRL_VOLUME_POS, /*_ctrlch1*/ AUDIO_CTRL_RW << AUDIO_FEATURE_UNIT_CTRL_MUTE_POS | AUDIO_CTRL_RW << AUDIO_FEATURE_UNIT_CTRL_VOLUME_POS, /*_ctrlch2*/ AUDIO_CTRL_RW << AUDIO_FEATURE_UNIT_CTRL_MUTE_POS | AUDIO_CTRL_RW << AUDIO_FEATURE_UNIT_CTRL_VOLUME_POS,/*_stridx*/ 0x00),\
+  /* Standard AS Interface Descriptor(4.9.1) */\
+  /* Interface 1, Alternate 0 - default alternate setting with 0 bandwidth */\
+  TUD_AUDIO_DESC_STD_AS_INT(/*_itfnum*/ (uint8_t)((_itfnum) + 1), /*_altset*/ 0x00, /*_nEPs*/ 0x00, /*_stridx*/ 0x00),\
+  /* Standard AS Interface Descriptor(4.9.1) */\
+  /* Interface 1, Alternate 1 - alternate interface for data streaming */\
+  TUD_AUDIO_DESC_STD_AS_INT(/*_itfnum*/ (uint8_t)((_itfnum) + 1), /*_altset*/ 0x01, /*_nEPs*/ 0x02, /*_stridx*/ 0x00),\
+  /* Class-Specific AS Interface Descriptor(4.9.2) */\
+  TUD_AUDIO_DESC_CS_AS_INT(/*_termid*/ 0x01, /*_ctrl*/ AUDIO_CTRL_NONE, /*_formattype*/ AUDIO_FORMAT_TYPE_I, /*_formats*/ AUDIO_DATA_FORMAT_TYPE_I_PCM, /*_nchannelsphysical*/ 0x02, /*_channelcfg*/ AUDIO_CHANNEL_CONFIG_NON_PREDEFINED, /*_stridx*/ 0x00),\
+  /* Type I Format Type Descriptor(2.3.1.6 - Audio Formats) */\
+  TUD_AUDIO_DESC_TYPE_I_FORMAT(_nBytesPerSample, _nBitsUsedPerSample),\
+  /* Standard AS Isochronous Audio Data Endpoint Descriptor(4.10.1.1) */\
+  TUD_AUDIO_DESC_STD_AS_ISO_EP(/*_ep*/ _epout, /*_attr*/ (uint8_t) ((uint8_t)TUSB_XFER_ISOCHRONOUS | (uint8_t)TUSB_ISO_EP_ATT_ASYNCHRONOUS | (uint8_t)TUSB_ISO_EP_ATT_DATA), /*_maxEPsize*/ _epsize, /*_interval*/ 0x01),\
+  /* Class-Specific AS Isochronous Audio Data Endpoint Descriptor(4.10.1.2) */\
+  TUD_AUDIO_DESC_CS_AS_ISO_EP(/*_attr*/ AUDIO_CS_AS_ISO_DATA_EP_ATT_NON_MAX_PACKETS_OK, /*_ctrl*/ AUDIO_CTRL_NONE, /*_lockdelayunit*/ AUDIO_CS_AS_ISO_DATA_EP_LOCK_DELAY_UNIT_MILLISEC, /*_lockdelay*/ 0x0001),\
+  /* Standard AS Isochronous Feedback Endpoint Descriptor(4.10.2.1) */\
+  TUD_AUDIO_DESC_STD_AS_ISO_FB_EP(/*_ep*/ _epfb, /*_interval*/ TUD_OPT_HIGH_SPEED ? 4 : 1)\
+
+#endif