audio_test_freertos & audio_4_channel_mic_freertos

20 files changed, 2218 insertions, 0 deletions

diff --git a/examples/device/audio_4_channel_mic_freertos/CMakeLists.txt b/examples/device/audio_4_channel_mic_freertos/CMakeLists.txt
new file mode 100644
index 000000000..639dde99a
--- /dev/null
+++ b/examples/device/audio_4_channel_mic_freertos/CMakeLists.txt
@@ -0,0 +1,22 @@
+cmake_minimum_required(VERSION 3.5)
+
+# TOP is absolute path to root directory of TinyUSB git repo
+# needed for esp32sx build. TOOD could be removed later on
+set(TOP "../../..")
+get_filename_component(TOP "${TOP}" REALPATH)
+
+include(${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})
+
+# Checks this example is valid for the family and initializes the project
+family_initialize_project(${PROJECT} ${CMAKE_CURRENT_LIST_DIR})
+
+# Check for -DFAMILY=
+if(FAMILY MATCHES "^esp32s[2-3]")
+else()
+  message(FATAL_ERROR "Invalid FAMILY specified: ${FAMILY}")
+endif()
diff --git a/examples/device/audio_4_channel_mic_freertos/Makefile b/examples/device/audio_4_channel_mic_freertos/Makefile
new file mode 100644
index 000000000..6c8c43ddd
--- /dev/null
+++ b/examples/device/audio_4_channel_mic_freertos/Makefile
@@ -0,0 +1,37 @@
+DEPS_SUBMODULES += lib/FreeRTOS-Kernel
+
+include ../../../tools/top.mk
+include ../../make.mk
+
+FREERTOS_SRC = lib/FreeRTOS-Kernel
+
+INC += \
+	src \
+	src/FreeRTOSConfig \
+	$(TOP)/hw \
+	$(TOP)/$(FREERTOS_SRC)/include \
+	$(TOP)/$(FREERTOS_SRC)/portable/GCC/$(FREERTOS_PORT)	
+
+# Example source
+EXAMPLE_SOURCE = \
+	src/freertos_hook.c \
+	src/main.c \
+	src/usb_descriptors.c
+	
+SRC_C += $(addprefix $(CURRENT_PATH)/, $(EXAMPLE_SOURCE))
+
+# FreeRTOS source, all files in port folder
+SRC_C += \
+	$(FREERTOS_SRC)/list.c \
+	$(FREERTOS_SRC)/queue.c \
+	$(FREERTOS_SRC)/tasks.c \
+	$(FREERTOS_SRC)/timers.c \
+	$(subst ../../../,,$(wildcard ../../../$(FREERTOS_SRC)/portable/GCC/$(FREERTOS_PORT)/*.c))
+
+# Suppress FreeRTOS warnings
+CFLAGS += -Wno-error=cast-qual -Wno-error=redundant-decls
+
+# FreeRTOS (lto + Os) linker issue
+LDFLAGS += -Wl,--undefined=vTaskSwitchContext
+
+include ../../rules.mk
diff --git a/examples/device/audio_4_channel_mic_freertos/README.md b/examples/device/audio_4_channel_mic_freertos/README.md
new file mode 100644
index 000000000..a35c16195
--- /dev/null
+++ b/examples/device/audio_4_channel_mic_freertos/README.md
@@ -0,0 +1,18 @@
+# How to build example for Esp32s3
+1. Load idf environment variables (eg. using the esp-idf alias `get_idf` if configured)
+
+2. cd into examples directory
+```
+$ cd /tinyusb/examples/device/audio_4_channel_mic_freertos
+```
+
+3. Run make in project directory specifying the board
+```
+$ make BOARD=espressif_s3_devkitc all
+```
+
+4. Flash the binary onto the esp32-s3 by copy-paste of the full command output by the esp-idf build system replacing **(PORT)** with eg. /dev/ttyUSB0
+
+eg.
+
+> /home/kaspernyhus/.espressif/python_env/idf4.4_py3.8_env/bin/python ../../../../esp-idf/components/esptool_py/esptool/esptool.py -p /dev/ttyUSB0 -b 460800 --before default_reset --after hard_reset --chip esp32s3  write_flash --flash_mode dio --flash_size detect --flash_freq 80m 0x0 _build/espressif_s3_devkitc/bootloader/bootloader.bin 0x8000 _build/espressif_s3_devkitc/partition_table/partition-table.bin 0x10000 _build/espressif_s3_devkitc/audio_4_channel_mic_freertos.bin
diff --git a/examples/device/audio_4_channel_mic_freertos/skip.txt b/examples/device/audio_4_channel_mic_freertos/skip.txt
new file mode 100644
index 000000000..ae9b57f1f
--- /dev/null
+++ b/examples/device/audio_4_channel_mic_freertos/skip.txt
@@ -0,0 +1,3 @@
+mcu:SAMD11
+mcu:SAME5X
+mcu:SAMG
\ No newline at end of file
diff --git a/examples/device/audio_4_channel_mic_freertos/src/CMakeLists.txt b/examples/device/audio_4_channel_mic_freertos/src/CMakeLists.txt
new file mode 100644
index 000000000..29e46d979
--- /dev/null
+++ b/examples/device/audio_4_channel_mic_freertos/src/CMakeLists.txt
@@ -0,0 +1,27 @@
+idf_component_register(SRCS "main.c" "usb_descriptors.c"
+  INCLUDE_DIRS "."
+  REQUIRES freertos soc)
+
+file(TO_NATIVE_PATH "${TOP}/hw/bsp/${FAMILY}/boards/${BOARD}/board.cmake" board_cmake)
+
+if(EXISTS ${board_cmake})
+  include(${board_cmake})
+endif()
+
+target_include_directories(${COMPONENT_TARGET} PUBLIC
+  "${TOP}/hw"
+  "${TOP}/src"
+)
+
+target_compile_definitions(${COMPONENT_TARGET} PUBLIC
+  ESP_PLATFORM
+)
+
+target_sources(${COMPONENT_TARGET} PUBLIC
+  "${TOP}/src/tusb.c"
+  "${TOP}/src/common/tusb_fifo.c"
+  "${TOP}/src/device/usbd.c"
+  "${TOP}/src/device/usbd_control.c"
+  "${TOP}/src/class/audio/audio_device.c"
+  "${TOP}/src/portable/espressif/esp32sx/dcd_esp32sx.c"
+)
\ No newline at end of file
diff --git a/examples/device/audio_4_channel_mic_freertos/src/FreeRTOSConfig/FreeRTOSConfig.h b/examples/device/audio_4_channel_mic_freertos/src/FreeRTOSConfig/FreeRTOSConfig.h
new file mode 100644
index 000000000..ccb620720
--- /dev/null
+++ b/examples/device/audio_4_channel_mic_freertos/src/FreeRTOSConfig/FreeRTOSConfig.h
@@ -0,0 +1,191 @@
+/*
+ * FreeRTOS Kernel V10.0.0
+ * Copyright (C) 2017 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
+ *
+ * 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. If you wish to use our Amazon
+ * FreeRTOS name, please do so in a fair use way that does not cause confusion.
+ *
+ * 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.
+ *
+ * http://www.FreeRTOS.org
+ * http://aws.amazon.com/freertos
+ *
+ * 1 tab == 4 spaces!
+ */
+
+
+#ifndef FREERTOS_CONFIG_H
+#define FREERTOS_CONFIG_H
+
+/*-----------------------------------------------------------
+ * Application specific definitions.
+ *
+ * These definitions should be adjusted for your particular hardware and
+ * application requirements.
+ *
+ * THESE PARAMETERS ARE DESCRIBED WITHIN THE 'CONFIGURATION' SECTION OF THE
+ * FreeRTOS API DOCUMENTATION AVAILABLE ON THE FreeRTOS.org WEB SITE.
+ *
+ * See http://www.freertos.org/a00110.html.
+ *----------------------------------------------------------*/
+
+// Include MCU header
+#include "bsp/board_mcu.h"
+
+#if CFG_TUSB_MCU == OPT_MCU_ESP32S2 || CFG_TUSB_MCU == OPT_MCU_ESP32S3
+  #error "ESP32-Sx should use IDF's FreeRTOSConfig.h"
+#endif
+
+// TODO fix later
+#if CFG_TUSB_MCU == OPT_MCU_MM32F327X
+  extern u32 SystemCoreClock;
+#else
+  extern uint32_t SystemCoreClock;
+#endif
+
+/* Cortex M23/M33 port configuration. */
+#define configENABLE_MPU								        0
+#define configENABLE_FPU								        1
+#define configENABLE_TRUSTZONE					        0
+#define configMINIMAL_SECURE_STACK_SIZE					( 1024 )
+
+#define configUSE_PREEMPTION                    1
+#define configUSE_PORT_OPTIMISED_TASK_SELECTION 0
+#define configCPU_CLOCK_HZ                      SystemCoreClock
+#define configTICK_RATE_HZ                      ( 1000 )
+#define configMAX_PRIORITIES                    ( 5 )
+#define configMINIMAL_STACK_SIZE                ( 128 )
+#define configTOTAL_HEAP_SIZE                   ( 0*1024 ) // dynamic is not used
+#define configMAX_TASK_NAME_LEN                 16
+#define configUSE_16_BIT_TICKS                  0
+#define configIDLE_SHOULD_YIELD                 1
+#define configUSE_MUTEXES                       1
+#define configUSE_RECURSIVE_MUTEXES             1
+#define configUSE_COUNTING_SEMAPHORES           1
+#define configQUEUE_REGISTRY_SIZE               2
+#define configUSE_QUEUE_SETS                    0
+#define configUSE_TIME_SLICING                  0
+#define configUSE_NEWLIB_REENTRANT              0
+#define configENABLE_BACKWARD_COMPATIBILITY     1
+#define configSTACK_ALLOCATION_FROM_SEPARATE_HEAP   0
+
+#define configSUPPORT_STATIC_ALLOCATION         1
+#define configSUPPORT_DYNAMIC_ALLOCATION        0
+
+/* Hook function related definitions. */
+#define configUSE_IDLE_HOOK                    0
+#define configUSE_TICK_HOOK                    0
+#define configUSE_MALLOC_FAILED_HOOK           0 // cause nested extern warning
+#define configCHECK_FOR_STACK_OVERFLOW         2
+
+/* Run time and task stats gathering related definitions. */
+#define configGENERATE_RUN_TIME_STATS          0
+#define configUSE_TRACE_FACILITY               1 // legacy trace
+#define configUSE_STATS_FORMATTING_FUNCTIONS   0
+
+/* Co-routine definitions. */
+#define configUSE_CO_ROUTINES                  0
+#define configMAX_CO_ROUTINE_PRIORITIES        2
+
+/* Software timer related definitions. */
+#define configUSE_TIMERS                       1
+#define configTIMER_TASK_PRIORITY              (configMAX_PRIORITIES-2)
+#define configTIMER_QUEUE_LENGTH               32
+#define configTIMER_TASK_STACK_DEPTH           configMINIMAL_STACK_SIZE
+
+/* Optional functions - most linkers will remove unused functions anyway. */
+#define INCLUDE_vTaskPrioritySet               0
+#define INCLUDE_uxTaskPriorityGet              0
+#define INCLUDE_vTaskDelete                    0
+#define INCLUDE_vTaskSuspend                   1 // required for queue, semaphore, mutex to be blocked indefinitely with portMAX_DELAY
+#define INCLUDE_xResumeFromISR                 0
+#define INCLUDE_vTaskDelayUntil                1
+#define INCLUDE_vTaskDelay                     1
+#define INCLUDE_xTaskGetSchedulerState         0
+#define INCLUDE_xTaskGetCurrentTaskHandle      0
+#define INCLUDE_uxTaskGetStackHighWaterMark    0
+#define INCLUDE_xTaskGetIdleTaskHandle         0
+#define INCLUDE_xTimerGetTimerDaemonTaskHandle 0
+#define INCLUDE_pcTaskGetTaskName              0
+#define INCLUDE_eTaskGetState                  0
+#define INCLUDE_xEventGroupSetBitFromISR       0
+#define INCLUDE_xTimerPendFunctionCall         0
+
+/* Define to trap errors during development. */
+// Halt CPU (breakpoint) when hitting error, only apply for Cortex M3, M4, M7
+#if defined(__ARM_ARCH_7M__) || defined (__ARM_ARCH_7EM__)
+  #define configASSERT(_exp) \
+    do {\
+      if ( !(_exp) ) { \
+        volatile uint32_t* ARM_CM_DHCSR =  ((volatile uint32_t*) 0xE000EDF0UL); /* Cortex M CoreDebug->DHCSR */ \
+        if ( (*ARM_CM_DHCSR) & 1UL ) {  /* Only halt mcu if debugger is attached */ \
+          taskDISABLE_INTERRUPTS(); \
+           __asm("BKPT #0\n"); \
+        }\
+      }\
+    } while(0)
+#else
+  #define configASSERT( x )
+#endif
+
+#ifdef __RX__
+/* Renesas RX series */
+#define vSoftwareInterruptISR					INT_Excep_ICU_SWINT
+#define vTickISR								INT_Excep_CMT0_CMI0
+#define configPERIPHERAL_CLOCK_HZ				(configCPU_CLOCK_HZ/2)
+#define configKERNEL_INTERRUPT_PRIORITY			1
+#define configMAX_SYSCALL_INTERRUPT_PRIORITY	4
+
+#else
+
+/* FreeRTOS hooks to NVIC vectors */
+#define xPortPendSVHandler    PendSV_Handler
+#define xPortSysTickHandler   SysTick_Handler
+#define vPortSVCHandler       SVC_Handler
+
+//--------------------------------------------------------------------+
+// Interrupt nesting behavior configuration.
+//--------------------------------------------------------------------+
+#if defined(__NVIC_PRIO_BITS)
+  // For Cortex-M specific: __NVIC_PRIO_BITS is defined in core_cmx.h
+	#define configPRIO_BITS       __NVIC_PRIO_BITS
+#elif defined(__ECLIC_INTCTLBITS)
+  // RISC-V Bumblebee core from nuclei
+  #define configPRIO_BITS       __ECLIC_INTCTLBITS
+#else
+  #error "FreeRTOS configPRIO_BITS to be defined"
+#endif
+
+/* The lowest interrupt priority that can be used in a call to a "set priority" function. */
+#define configLIBRARY_LOWEST_INTERRUPT_PRIORITY			  ((1<<configPRIO_BITS) - 1)
+
+/* The highest interrupt priority that can be used by any interrupt service
+routine that makes calls to interrupt safe FreeRTOS API functions.  DO NOT CALL
+INTERRUPT SAFE FREERTOS API FUNCTIONS FROM ANY INTERRUPT THAT HAS A HIGHER
+PRIORITY THAN THIS! (higher priorities are lower numeric values. */
+#define configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY	2
+
+/* Interrupt priorities used by the kernel port layer itself.  These are generic
+to all Cortex-M ports, and do not rely on any particular library functions. */
+#define configKERNEL_INTERRUPT_PRIORITY 		          ( configLIBRARY_LOWEST_INTERRUPT_PRIORITY << (8 - configPRIO_BITS) )
+
+/* !!!! configMAX_SYSCALL_INTERRUPT_PRIORITY must not be set to zero !!!!
+See http://www.FreeRTOS.org/RTOS-Cortex-M3-M4.html. */
+#define configMAX_SYSCALL_INTERRUPT_PRIORITY 	        ( configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY << (8 - configPRIO_BITS) )
+
+#endif
+
+#endif /* __FREERTOS_CONFIG__H */
diff --git a/examples/device/audio_4_channel_mic_freertos/src/main.c b/examples/device/audio_4_channel_mic_freertos/src/main.c
new file mode 100644
index 000000000..3b9795946
--- /dev/null
+++ b/examples/device/audio_4_channel_mic_freertos/src/main.c
@@ -0,0 +1,488 @@
+/*
+ * 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.
+ *
+ */
+
+/* plot_audio_samples.py requires following modules:
+ * $ sudo apt install libportaudio
+ * $ pip3 install sounddevice matplotlib
+ *
+ * Then run
+ * $ python3 plot_audio_samples.py
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "bsp/board.h"
+#include "tusb.h"
+
+// ESP-IDF need "freertos/" prefix in include path.
+// CFG_TUSB_OS_INC_PATH should be defined accordingly.
+#include "freertos/FreeRTOS.h"
+#include "freertos/semphr.h"
+#include "freertos/queue.h"
+#include "freertos/task.h"
+#include "freertos/timers.h"
+
+#define USBD_STACK_SIZE     4096
+
+
+//--------------------------------------------------------------------+
+// MACRO CONSTANT TYPEDEF PROTYPES
+//--------------------------------------------------------------------+
+
+#ifndef AUDIO_SAMPLE_RATE
+#define AUDIO_SAMPLE_RATE   48000
+#endif
+
+/* 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 timer
+StaticTimer_t blinky_tmdef;
+TimerHandle_t blinky_tm;
+StackType_t  usb_device_stack[USBD_STACK_SIZE];
+StaticTask_t usb_device_taskdef;
+
+
+// Audio controls
+// Current states
+bool mute[CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_TX + 1]; 				          // +1 for master channel 0
+uint16_t volume[CFG_TUD_AUDIO_FUNC_1_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_FUNC_1_N_CHANNELS_TX+1]; 			// Volume range state
+audio_control_range_4_n_t(1) sampleFreqRng; 						// Sample frequency range state
+
+// Audio test data
+uint16_t i2s_dummy_buffer[CFG_TUD_AUDIO_EP_SZ_IN/2];   // Ensure half word aligned
+uint16_t samples[] = {0, 0, 0, 0};
+
+void led_blinky_cb(TimerHandle_t xTimer);
+void usb_device_task(void* param);
+void audio_task(void);
+
+/*------------- MAIN -------------*/
+int main(void)
+{
+  board_init();
+
+  // soft timer for blinky
+  blinky_tm = xTimerCreateStatic(NULL, pdMS_TO_TICKS(BLINK_NOT_MOUNTED), true, NULL, led_blinky_cb, &blinky_tmdef);
+  xTimerStart(blinky_tm, 0);
+
+  // Init values
+  sampFreq = AUDIO_SAMPLE_RATE;
+  clkValid = 1;
+
+  sampleFreqRng.wNumSubRanges = 1;
+  sampleFreqRng.subrange[0].bMin = AUDIO_SAMPLE_RATE;
+  sampleFreqRng.subrange[0].bMax = AUDIO_SAMPLE_RATE;
+  sampleFreqRng.subrange[0].bRes = 0;
+
+  // Create a task for tinyusb device stack
+  (void) xTaskCreateStatic( usb_device_task, "usbd", USBD_STACK_SIZE, NULL, configMAX_PRIORITIES-1, usb_device_stack, &usb_device_taskdef);
+
+  // skip starting scheduler (and return) for ESP32-S2 or ESP32-S3
+  #if !TU_CHECK_MCU(OPT_MCU_ESP32S2, OPT_MCU_ESP32S3)
+    vTaskStartScheduler();
+  #endif
+
+  return 0;
+}
+
+#if TU_CHECK_MCU(OPT_MCU_ESP32S2, OPT_MCU_ESP32S3)
+void app_main(void)
+{
+  main();
+}
+#endif
+
+// USB Device Driver task
+// This top level thread process all usb events and invoke callbacks
+void usb_device_task(void* param)
+{
+  (void) param;
+
+  // This should be called after scheduler/kernel is started.
+  // Otherwise it could cause kernel issue since USB IRQ handler does use RTOS queue API.
+  tusb_init();
+
+  // RTOS forever loop
+  while (1)
+  {
+    // tinyusb device task
+    tud_task();
+  }
+}
+
+//--------------------------------------------------------------------+
+// Device callbacks
+//--------------------------------------------------------------------+
+
+// Invoked when device is mounted
+void tud_mount_cb(void)
+{
+  xTimerChangePeriod(blinky_tm, pdMS_TO_TICKS(BLINK_MOUNTED), 0);
+}
+
+// Invoked when device is unmounted
+void tud_umount_cb(void)
+{
+  xTimerChangePeriod(blinky_tm, pdMS_TO_TICKS(BLINK_NOT_MOUNTED), 0);
+}
+
+// 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;
+  xTimerChangePeriod(blinky_tm, pdMS_TO_TICKS(BLINK_SUSPENDED), 0);
+}
+
+// Invoked when usb bus is resumed
+void tud_resume_cb(void)
+{
+  xTimerChangePeriod(blinky_tm, pdMS_TO_TICKS(BLINK_MOUNTED), 0);
+}
+
+//--------------------------------------------------------------------+
+// 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;
+  (void) pBuff;
+
+  // 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);
+
+  (void) channelNum; (void) ctrlSel; (void) ep;
+
+  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;
+  (void) pBuff;
+
+  // 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);
+
+  (void) channelNum; (void) ctrlSel; (void) itf;
+
+  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);
+
+  (void) itf;
+
+  // 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);
+
+  (void) channelNum; (void) ctrlSel; (void) ep;
+
+  //	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);
+
+  (void) channelNum; (void) ctrlSel; (void) itf;
+
+  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));
+      }
+      break;
+
+        // 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;
+        }
+      break;
+
+        // 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;
+        }
+      break;
+
+      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
+}
+
+bool tud_audio_tx_done_pre_load_cb(uint8_t rhport, uint8_t itf, uint8_t ep_in, uint8_t cur_alt_setting)
+{
+  (void) rhport;
+  (void) itf;
+  (void) ep_in;
+  (void) cur_alt_setting;
+
+  tud_audio_write((uint8_t*)i2s_dummy_buffer, CFG_TUD_AUDIO_EP_SZ_IN);
+
+  return true;
+}
+
+bool tud_audio_tx_done_post_load_cb(uint8_t rhport, uint16_t n_bytes_copied, uint8_t itf, uint8_t ep_in, uint8_t cur_alt_setting)
+{
+  (void) rhport;
+  (void) n_bytes_copied;
+  (void) itf;
+  (void) ep_in;
+  (void) cur_alt_setting;
+
+  uint16_t* p_buff = i2s_dummy_buffer;
+  for (int samples_num = 0; samples_num < AUDIO_SAMPLE_RATE/1000; samples_num++) {
+    for (int ch=0; ch < CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_TX; ch++) {
+      *p_buff++ = samples[ch];
+      samples[ch] = samples[ch]+(ch+1);
+    }
+  }
+
+  return true;
+}
+
+bool tud_audio_set_itf_close_EP_cb(uint8_t rhport, tusb_control_request_t const * p_request)
+{
+  (void) rhport;
+  (void) p_request;
+
+  return true;
+}
+
+///--------------------------------------------------------------------+
+// BLINKING TASK
+//--------------------------------------------------------------------+
+void led_blinky_cb(TimerHandle_t xTimer)
+{
+  (void) xTimer;
+  static bool led_state = false;
+
+  board_led_write(led_state);
+  led_state = 1 - led_state; // toggle
+}
diff --git a/examples/device/audio_4_channel_mic_freertos/src/plot_audio_samples.py b/examples/device/audio_4_channel_mic_freertos/src/plot_audio_samples.py
new file mode 100644
index 000000000..9ab15135d
--- /dev/null
+++ b/examples/device/audio_4_channel_mic_freertos/src/plot_audio_samples.py
@@ -0,0 +1,34 @@
+import sounddevice as sd
+import matplotlib.pyplot as plt
+import numpy as np
+import platform
+
+if __name__ == '__main__':
+
+    # If you got "ValueError: No input device matching", that is because your PC name example device
+    # differently from tested list below. Uncomment the next line to see full list and try to pick correct one
+    # print(sd.query_devices())
+
+    fs = 48000  		# Sample rate
+    duration = 100e-3   # Duration of recording
+
+    if platform.system() == 'Windows':
+        # WDM-KS is needed since there are more than one MicNode device APIs (at least in Windows)
+        device = 'Microphone (MicNode_4_Ch), Windows WDM-KS'
+    elif platform.system() == 'Darwin':
+        device = 'MicNode_4_Ch'
+    else:
+        device ='default'
+
+    myrecording = sd.rec(int(duration * fs), samplerate=fs, channels=4, dtype='int16', device=device)
+    print('Waiting...')
+    sd.wait()  # Wait until recording is finished
+    print('Done!')
+
+    time = np.arange(0, duration, 1 / fs)  # time vector
+    plt.plot(time, myrecording)
+    plt.xlabel('Time [s]')
+    plt.ylabel('Amplitude')
+    plt.title('MicNode 4 Channel')
+    plt.show()
+    
\ No newline at end of file
diff --git a/examples/device/audio_4_channel_mic_freertos/src/tusb_config.h b/examples/device/audio_4_channel_mic_freertos/src/tusb_config.h
new file mode 100644
index 000000000..f13865084
--- /dev/null
+++ b/examples/device/audio_4_channel_mic_freertos/src/tusb_config.h
@@ -0,0 +1,128 @@
+/*
+ * 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
+
+// RHPort number used for device can be defined by board.mk, default to port 0
+#ifndef BOARD_DEVICE_RHPORT_NUM
+  #define BOARD_DEVICE_RHPORT_NUM     0
+#endif
+
+#ifndef BOARD_DEVICE_RHPORT_SPEED
+  #define BOARD_DEVICE_RHPORT_SPEED   OPT_MODE_FULL_SPEED
+#endif
+
+#define CFG_TUSB_RHPORT0_MODE       OPT_MODE_DEVICE
+
+#ifndef CFG_TUSB_OS
+  #define CFG_TUSB_OS                 OPT_OS_FREERTOS
+#endif
+
+// Espressif IDF requires "freertos/" prefix in include path
+#if TU_CHECK_MCU(OPT_MCU_ESP32S2, OPT_MCU_ESP32S3)
+  #define CFG_TUSB_OS_INC_PATH    freertos/
+#endif
+
+#ifndef CFG_TUSB_DEBUG
+  #define CFG_TUSB_DEBUG              0
+#endif
+
+// 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
+//--------------------------------------------------------------------
+
+// Have a look into audio_device.h for all configurations
+
+#define CFG_TUD_AUDIO_FUNC_1_DESC_LEN                                 TUD_AUDIO_MIC_FOUR_CH_DESC_LEN
+
+#define CFG_TUD_AUDIO_FUNC_1_N_AS_INT                                 1
+#define CFG_TUD_AUDIO_FUNC_1_CTRL_BUF_SZ                              64
+
+#define CFG_TUD_AUDIO_ENABLE_EP_IN                                    1
+#define CFG_TUD_AUDIO_FUNC_1_N_BYTES_PER_SAMPLE_TX                    2         // This value is not required by the driver, it parses this information from the descriptor once the alternate interface is set by the host - we use it for the setup
+#define CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_TX                            4         // This value is not required by the driver, it parses this information from the descriptor once the alternate interface is set by the host - we use it for the setup
+#define CFG_TUD_AUDIO_EP_SZ_IN                                        48 * CFG_TUD_AUDIO_FUNC_1_N_BYTES_PER_SAMPLE_TX * CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_TX      // 48 Samples (48 kHz) x 2 Bytes/Sample x CFG_TUD_AUDIO_N_CHANNELS_TX Channels - the Windows driver always needs an extra sample per channel of space more, otherwise it complains... found by trial and error
+#define CFG_TUD_AUDIO_FUNC_1_EP_IN_SZ_MAX                             CFG_TUD_AUDIO_EP_SZ_IN
+#define CFG_TUD_AUDIO_FUNC_1_EP_IN_SW_BUF_SZ                          CFG_TUD_AUDIO_EP_SZ_IN
+
+#define CFG_TUD_AUDIO_ENABLE_ENCODING                                 0
+#define CFG_TUD_AUDIO_ENABLE_TYPE_I_ENCODING                          0
+#define CFG_TUD_AUDIO_FUNC_1_CHANNEL_PER_FIFO_TX                      2         // One I2S stream contains two channels, each stream is saved within one support FIFO - this value is currently fixed, the driver does not support a changing value
+#define CFG_TUD_AUDIO_FUNC_1_N_TX_SUPP_SW_FIFO                        (CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_TX / CFG_TUD_AUDIO_FUNC_1_CHANNEL_PER_FIFO_TX)
+#define CFG_TUD_AUDIO_FUNC_1_TX_SUPP_SW_FIFO_SZ                       (CFG_TUD_AUDIO_EP_SZ_IN / CFG_TUD_AUDIO_FUNC_1_N_TX_SUPP_SW_FIFO)
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _TUSB_CONFIG_H_ */
diff --git a/examples/device/audio_4_channel_mic_freertos/src/usb_descriptors.c b/examples/device/audio_4_channel_mic_freertos/src/usb_descriptors.c
new file mode 100644
index 000000000..16355a7fc
--- /dev/null
+++ b/examples/device/audio_4_channel_mic_freertos/src/usb_descriptors.c
@@ -0,0 +1,165 @@
+/*
+ * 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_FOUR_CH_DESC_LEN)
+
+#if TU_CHECK_MCU(OPT_MCU_LPC175X_6X, OPT_MCU_LPC177X_8X, 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
+
+#elif TU_CHECK_MCU(OPT_MCU_NRF5X)
+  // nRF5x ISO can only be endpoint 8
+  #define EPNUM_AUDIO   0x08
+
+#else
+  #define EPNUM_AUDIO   0x01
+#endif
+
+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, 0x00, 100),
+
+  // Interface number, string index, EP Out & EP In address, EP size
+  TUD_AUDIO_MIC_FOUR_CH_DESCRIPTOR(/*_itfnum*/ ITF_NUM_AUDIO_CONTROL, /*_stridx*/ 0, /*_nBytesPerSample*/ CFG_TUD_AUDIO_FUNC_1_N_BYTES_PER_SAMPLE_TX, /*_nBitsUsedPerSample*/ CFG_TUD_AUDIO_FUNC_1_N_BYTES_PER_SAMPLE_TX*8, /*_epin*/ 0x80 | EPNUM_AUDIO, /*_epsize*/ CFG_TUD_AUDIO_EP_SZ_IN)
+};
+
+// 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_4_Ch",    		          // 2: Product
+    "123458",                      	// 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/examples/device/audio_test_freertos/CMakeLists.txt b/examples/device/audio_test_freertos/CMakeLists.txt
new file mode 100644
index 000000000..639dde99a
--- /dev/null
+++ b/examples/device/audio_test_freertos/CMakeLists.txt
@@ -0,0 +1,22 @@
+cmake_minimum_required(VERSION 3.5)
+
+# TOP is absolute path to root directory of TinyUSB git repo
+# needed for esp32sx build. TOOD could be removed later on
+set(TOP "../../..")
+get_filename_component(TOP "${TOP}" REALPATH)
+
+include(${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})
+
+# Checks this example is valid for the family and initializes the project
+family_initialize_project(${PROJECT} ${CMAKE_CURRENT_LIST_DIR})
+
+# Check for -DFAMILY=
+if(FAMILY MATCHES "^esp32s[2-3]")
+else()
+  message(FATAL_ERROR "Invalid FAMILY specified: ${FAMILY}")
+endif()
diff --git a/examples/device/audio_test_freertos/Makefile b/examples/device/audio_test_freertos/Makefile
new file mode 100644
index 000000000..e5b88df5e
--- /dev/null
+++ b/examples/device/audio_test_freertos/Makefile
@@ -0,0 +1,38 @@
+DEPS_SUBMODULES += lib/FreeRTOS-Kernel
+
+include ../../../tools/top.mk
+include ../../make.mk
+
+FREERTOS_SRC = lib/FreeRTOS-Kernel
+
+INC += \
+	src \
+	src/FreeRTOSConfig \
+	$(TOP)/hw \
+	$(TOP)/$(FREERTOS_SRC)/include \
+	$(TOP)/$(FREERTOS_SRC)/portable/GCC/$(FREERTOS_PORT)
+	
+# Example source
+EXAMPLE_SOURCE = \
+	src/freertos_hook.c \
+	src/main.c \
+	src/msc_disk.c \
+	src/usb_descriptors.c
+
+SRC_C += $(addprefix $(CURRENT_PATH)/, $(EXAMPLE_SOURCE))
+
+# FreeRTOS source, all files in port folder
+SRC_C += \
+	$(FREERTOS_SRC)/list.c \
+	$(FREERTOS_SRC)/queue.c \
+	$(FREERTOS_SRC)/tasks.c \
+	$(FREERTOS_SRC)/timers.c \
+	$(subst ../../../,,$(wildcard ../../../$(FREERTOS_SRC)/portable/GCC/$(FREERTOS_PORT)/*.c))
+
+# Suppress FreeRTOS warnings
+CFLAGS += -Wno-error=cast-qual
+
+# FreeRTOS (lto + Os) linker issue
+LDFLAGS += -Wl,--undefined=vTaskSwitchContext
+
+include ../../rules.mk
\ No newline at end of file
diff --git a/examples/device/audio_test_freertos/README.md b/examples/device/audio_test_freertos/README.md
new file mode 100644
index 000000000..077a2a1b6
--- /dev/null
+++ b/examples/device/audio_test_freertos/README.md
@@ -0,0 +1,18 @@
+# How to build example for Esp32s3
+1. Load idf environment variables (eg. using the esp-idf alias `get_idf` if configured)
+
+2. cd into examples directory
+```
+$ cd /tinyusb/examples/device/audio_test_freertos
+```
+
+3. Run make in project directory specifying the board
+```
+$ make BOARD=espressif_s3_devkitc all
+```
+
+4. Flash the binary onto the esp32-s3 by copy-paste of the full command output by the esp-idf build system replacing **(PORT)** with eg. /dev/ttyUSB0
+
+eg.
+
+> /home/kaspernyhus/.espressif/python_env/idf4.4_py3.8_env/bin/python ../../../../esp-idf/components/esptool_py/esptool/esptool.py -p /dev/ttyUSB0 -b 460800 --before default_reset --after hard_reset --chip esp32s3  write_flash --flash_mode dio --flash_size detect --flash_freq 80m 0x0 _build/espressif_s3_devkitc/bootloader/bootloader.bin 0x8000 _build/espressif_s3_devkitc/partition_table/partition-table.bin 0x10000 _build/espressif_s3_devkitc/audio_test_freertos.bin
\ No newline at end of file
diff --git a/examples/device/audio_test_freertos/skip.txt b/examples/device/audio_test_freertos/skip.txt
new file mode 100644
index 000000000..ae9b57f1f
--- /dev/null
+++ b/examples/device/audio_test_freertos/skip.txt
@@ -0,0 +1,3 @@
+mcu:SAMD11
+mcu:SAME5X
+mcu:SAMG
\ No newline at end of file
diff --git a/examples/device/audio_test_freertos/src/CMakeLists.txt b/examples/device/audio_test_freertos/src/CMakeLists.txt
new file mode 100644
index 000000000..29e46d979
--- /dev/null
+++ b/examples/device/audio_test_freertos/src/CMakeLists.txt
@@ -0,0 +1,27 @@
+idf_component_register(SRCS "main.c" "usb_descriptors.c"
+  INCLUDE_DIRS "."
+  REQUIRES freertos soc)
+
+file(TO_NATIVE_PATH "${TOP}/hw/bsp/${FAMILY}/boards/${BOARD}/board.cmake" board_cmake)
+
+if(EXISTS ${board_cmake})
+  include(${board_cmake})
+endif()
+
+target_include_directories(${COMPONENT_TARGET} PUBLIC
+  "${TOP}/hw"
+  "${TOP}/src"
+)
+
+target_compile_definitions(${COMPONENT_TARGET} PUBLIC
+  ESP_PLATFORM
+)
+
+target_sources(${COMPONENT_TARGET} PUBLIC
+  "${TOP}/src/tusb.c"
+  "${TOP}/src/common/tusb_fifo.c"
+  "${TOP}/src/device/usbd.c"
+  "${TOP}/src/device/usbd_control.c"
+  "${TOP}/src/class/audio/audio_device.c"
+  "${TOP}/src/portable/espressif/esp32sx/dcd_esp32sx.c"
+)
\ No newline at end of file
diff --git a/examples/device/audio_test_freertos/src/FreeRTOSConfig/FreeRTOSConfig.h b/examples/device/audio_test_freertos/src/FreeRTOSConfig/FreeRTOSConfig.h
new file mode 100644
index 000000000..ccb620720
--- /dev/null
+++ b/examples/device/audio_test_freertos/src/FreeRTOSConfig/FreeRTOSConfig.h
@@ -0,0 +1,191 @@
+/*
+ * FreeRTOS Kernel V10.0.0
+ * Copyright (C) 2017 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
+ *
+ * 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. If you wish to use our Amazon
+ * FreeRTOS name, please do so in a fair use way that does not cause confusion.
+ *
+ * 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.
+ *
+ * http://www.FreeRTOS.org
+ * http://aws.amazon.com/freertos
+ *
+ * 1 tab == 4 spaces!
+ */
+
+
+#ifndef FREERTOS_CONFIG_H
+#define FREERTOS_CONFIG_H
+
+/*-----------------------------------------------------------
+ * Application specific definitions.
+ *
+ * These definitions should be adjusted for your particular hardware and
+ * application requirements.
+ *
+ * THESE PARAMETERS ARE DESCRIBED WITHIN THE 'CONFIGURATION' SECTION OF THE
+ * FreeRTOS API DOCUMENTATION AVAILABLE ON THE FreeRTOS.org WEB SITE.
+ *
+ * See http://www.freertos.org/a00110.html.
+ *----------------------------------------------------------*/
+
+// Include MCU header
+#include "bsp/board_mcu.h"
+
+#if CFG_TUSB_MCU == OPT_MCU_ESP32S2 || CFG_TUSB_MCU == OPT_MCU_ESP32S3
+  #error "ESP32-Sx should use IDF's FreeRTOSConfig.h"
+#endif
+
+// TODO fix later
+#if CFG_TUSB_MCU == OPT_MCU_MM32F327X
+  extern u32 SystemCoreClock;
+#else
+  extern uint32_t SystemCoreClock;
+#endif
+
+/* Cortex M23/M33 port configuration. */
+#define configENABLE_MPU								        0
+#define configENABLE_FPU								        1
+#define configENABLE_TRUSTZONE					        0
+#define configMINIMAL_SECURE_STACK_SIZE					( 1024 )
+
+#define configUSE_PREEMPTION                    1
+#define configUSE_PORT_OPTIMISED_TASK_SELECTION 0
+#define configCPU_CLOCK_HZ                      SystemCoreClock
+#define configTICK_RATE_HZ                      ( 1000 )
+#define configMAX_PRIORITIES                    ( 5 )
+#define configMINIMAL_STACK_SIZE                ( 128 )
+#define configTOTAL_HEAP_SIZE                   ( 0*1024 ) // dynamic is not used
+#define configMAX_TASK_NAME_LEN                 16
+#define configUSE_16_BIT_TICKS                  0
+#define configIDLE_SHOULD_YIELD                 1
+#define configUSE_MUTEXES                       1
+#define configUSE_RECURSIVE_MUTEXES             1
+#define configUSE_COUNTING_SEMAPHORES           1
+#define configQUEUE_REGISTRY_SIZE               2
+#define configUSE_QUEUE_SETS                    0
+#define configUSE_TIME_SLICING                  0
+#define configUSE_NEWLIB_REENTRANT              0
+#define configENABLE_BACKWARD_COMPATIBILITY     1
+#define configSTACK_ALLOCATION_FROM_SEPARATE_HEAP   0
+
+#define configSUPPORT_STATIC_ALLOCATION         1
+#define configSUPPORT_DYNAMIC_ALLOCATION        0
+
+/* Hook function related definitions. */
+#define configUSE_IDLE_HOOK                    0
+#define configUSE_TICK_HOOK                    0
+#define configUSE_MALLOC_FAILED_HOOK           0 // cause nested extern warning
+#define configCHECK_FOR_STACK_OVERFLOW         2
+
+/* Run time and task stats gathering related definitions. */
+#define configGENERATE_RUN_TIME_STATS          0
+#define configUSE_TRACE_FACILITY               1 // legacy trace
+#define configUSE_STATS_FORMATTING_FUNCTIONS   0
+
+/* Co-routine definitions. */
+#define configUSE_CO_ROUTINES                  0
+#define configMAX_CO_ROUTINE_PRIORITIES        2
+
+/* Software timer related definitions. */
+#define configUSE_TIMERS                       1
+#define configTIMER_TASK_PRIORITY              (configMAX_PRIORITIES-2)
+#define configTIMER_QUEUE_LENGTH               32
+#define configTIMER_TASK_STACK_DEPTH           configMINIMAL_STACK_SIZE
+
+/* Optional functions - most linkers will remove unused functions anyway. */
+#define INCLUDE_vTaskPrioritySet               0
+#define INCLUDE_uxTaskPriorityGet              0
+#define INCLUDE_vTaskDelete                    0
+#define INCLUDE_vTaskSuspend                   1 // required for queue, semaphore, mutex to be blocked indefinitely with portMAX_DELAY
+#define INCLUDE_xResumeFromISR                 0
+#define INCLUDE_vTaskDelayUntil                1
+#define INCLUDE_vTaskDelay                     1
+#define INCLUDE_xTaskGetSchedulerState         0
+#define INCLUDE_xTaskGetCurrentTaskHandle      0
+#define INCLUDE_uxTaskGetStackHighWaterMark    0
+#define INCLUDE_xTaskGetIdleTaskHandle         0
+#define INCLUDE_xTimerGetTimerDaemonTaskHandle 0
+#define INCLUDE_pcTaskGetTaskName              0
+#define INCLUDE_eTaskGetState                  0
+#define INCLUDE_xEventGroupSetBitFromISR       0
+#define INCLUDE_xTimerPendFunctionCall         0
+
+/* Define to trap errors during development. */
+// Halt CPU (breakpoint) when hitting error, only apply for Cortex M3, M4, M7
+#if defined(__ARM_ARCH_7M__) || defined (__ARM_ARCH_7EM__)
+  #define configASSERT(_exp) \
+    do {\
+      if ( !(_exp) ) { \
+        volatile uint32_t* ARM_CM_DHCSR =  ((volatile uint32_t*) 0xE000EDF0UL); /* Cortex M CoreDebug->DHCSR */ \
+        if ( (*ARM_CM_DHCSR) & 1UL ) {  /* Only halt mcu if debugger is attached */ \
+          taskDISABLE_INTERRUPTS(); \
+           __asm("BKPT #0\n"); \
+        }\
+      }\
+    } while(0)
+#else
+  #define configASSERT( x )
+#endif
+
+#ifdef __RX__
+/* Renesas RX series */
+#define vSoftwareInterruptISR					INT_Excep_ICU_SWINT
+#define vTickISR								INT_Excep_CMT0_CMI0
+#define configPERIPHERAL_CLOCK_HZ				(configCPU_CLOCK_HZ/2)
+#define configKERNEL_INTERRUPT_PRIORITY			1
+#define configMAX_SYSCALL_INTERRUPT_PRIORITY	4
+
+#else
+
+/* FreeRTOS hooks to NVIC vectors */
+#define xPortPendSVHandler    PendSV_Handler
+#define xPortSysTickHandler   SysTick_Handler
+#define vPortSVCHandler       SVC_Handler
+
+//--------------------------------------------------------------------+
+// Interrupt nesting behavior configuration.
+//--------------------------------------------------------------------+
+#if defined(__NVIC_PRIO_BITS)
+  // For Cortex-M specific: __NVIC_PRIO_BITS is defined in core_cmx.h
+	#define configPRIO_BITS       __NVIC_PRIO_BITS
+#elif defined(__ECLIC_INTCTLBITS)
+  // RISC-V Bumblebee core from nuclei
+  #define configPRIO_BITS       __ECLIC_INTCTLBITS
+#else
+  #error "FreeRTOS configPRIO_BITS to be defined"
+#endif
+
+/* The lowest interrupt priority that can be used in a call to a "set priority" function. */
+#define configLIBRARY_LOWEST_INTERRUPT_PRIORITY			  ((1<<configPRIO_BITS) - 1)
+
+/* The highest interrupt priority that can be used by any interrupt service
+routine that makes calls to interrupt safe FreeRTOS API functions.  DO NOT CALL
+INTERRUPT SAFE FREERTOS API FUNCTIONS FROM ANY INTERRUPT THAT HAS A HIGHER
+PRIORITY THAN THIS! (higher priorities are lower numeric values. */
+#define configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY	2
+
+/* Interrupt priorities used by the kernel port layer itself.  These are generic
+to all Cortex-M ports, and do not rely on any particular library functions. */
+#define configKERNEL_INTERRUPT_PRIORITY 		          ( configLIBRARY_LOWEST_INTERRUPT_PRIORITY << (8 - configPRIO_BITS) )
+
+/* !!!! configMAX_SYSCALL_INTERRUPT_PRIORITY must not be set to zero !!!!
+See http://www.FreeRTOS.org/RTOS-Cortex-M3-M4.html. */
+#define configMAX_SYSCALL_INTERRUPT_PRIORITY 	        ( configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY << (8 - configPRIO_BITS) )
+
+#endif
+
+#endif /* __FREERTOS_CONFIG__H */
diff --git a/examples/device/audio_test_freertos/src/main.c b/examples/device/audio_test_freertos/src/main.c
new file mode 100644
index 000000000..5744b1b48
--- /dev/null
+++ b/examples/device/audio_test_freertos/src/main.c
@@ -0,0 +1,486 @@
+/*
+ * 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.
+ *
+ */
+
+/* plot_audio_samples.py requires following modules:
+ * $ sudo apt install libportaudio
+ * $ pip3 install sounddevice matplotlib
+ *
+ * Then run
+ * $ python3 plot_audio_samples.py
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "bsp/board.h"
+#include "tusb.h"
+
+// ESP-IDF need "freertos/" prefix in include path.
+// CFG_TUSB_OS_INC_PATH should be defined accordingly.
+#include "freertos/FreeRTOS.h"
+#include "freertos/semphr.h"
+#include "freertos/queue.h"
+#include "freertos/task.h"
+#include "freertos/timers.h"
+
+#define USBD_STACK_SIZE     4096
+
+
+//--------------------------------------------------------------------+
+// MACRO CONSTANT TYPEDEF PROTYPES
+//--------------------------------------------------------------------+
+
+#ifndef AUDIO_SAMPLE_RATE
+#define AUDIO_SAMPLE_RATE   48000
+#endif
+
+/* 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 timer
+StaticTimer_t blinky_tmdef;
+TimerHandle_t blinky_tm;
+StackType_t  usb_device_stack[USBD_STACK_SIZE];
+StaticTask_t usb_device_taskdef;
+
+
+// Audio controls
+// Current states
+bool mute[CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_TX + 1]; 				          // +1 for master channel 0
+uint16_t volume[CFG_TUD_AUDIO_FUNC_1_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_FUNC_1_N_CHANNELS_TX+1]; 			// Volume range state
+audio_control_range_4_n_t(1) sampleFreqRng; 						// Sample frequency range state
+
+// Audio test data
+uint16_t test_buffer_audio[CFG_TUD_AUDIO_EP_SZ_IN/2];
+uint16_t startVal = 0;
+
+void led_blinky_cb(TimerHandle_t xTimer);
+void usb_device_task(void* param);
+void audio_task(void);
+
+/*------------- MAIN -------------*/
+int main(void)
+{
+  board_init();
+
+  // soft timer for blinky
+  blinky_tm = xTimerCreateStatic(NULL, pdMS_TO_TICKS(BLINK_NOT_MOUNTED), true, NULL, led_blinky_cb, &blinky_tmdef);
+  xTimerStart(blinky_tm, 0);
+
+  // Init values
+  sampFreq = AUDIO_SAMPLE_RATE;
+  clkValid = 1;
+
+  sampleFreqRng.wNumSubRanges = 1;
+  sampleFreqRng.subrange[0].bMin = AUDIO_SAMPLE_RATE;
+  sampleFreqRng.subrange[0].bMax = AUDIO_SAMPLE_RATE;
+  sampleFreqRng.subrange[0].bRes = 0;
+
+  // Create a task for tinyusb device stack
+  (void) xTaskCreateStatic( usb_device_task, "usbd", USBD_STACK_SIZE, NULL, configMAX_PRIORITIES-1, usb_device_stack, &usb_device_taskdef);
+
+  // skip starting scheduler (and return) for ESP32-S2 or ESP32-S3
+  #if !TU_CHECK_MCU(OPT_MCU_ESP32S2, OPT_MCU_ESP32S3)
+    vTaskStartScheduler();
+  #endif
+
+  return 0;
+}
+
+#if TU_CHECK_MCU(OPT_MCU_ESP32S2, OPT_MCU_ESP32S3)
+void app_main(void)
+{
+  main();
+}
+#endif
+
+// USB Device Driver task
+// This top level thread process all usb events and invoke callbacks
+void usb_device_task(void* param)
+{
+  (void) param;
+
+  // This should be called after scheduler/kernel is started.
+  // Otherwise it could cause kernel issue since USB IRQ handler does use RTOS queue API.
+  tusb_init();
+
+  // RTOS forever loop
+  while (1)
+  {
+    // tinyusb device task
+    tud_task();
+  }
+}
+
+//--------------------------------------------------------------------+
+// Device callbacks
+//--------------------------------------------------------------------+
+
+// Invoked when device is mounted
+void tud_mount_cb(void)
+{
+  xTimerChangePeriod(blinky_tm, pdMS_TO_TICKS(BLINK_MOUNTED), 0);
+}
+
+// Invoked when device is unmounted
+void tud_umount_cb(void)
+{
+  xTimerChangePeriod(blinky_tm, pdMS_TO_TICKS(BLINK_NOT_MOUNTED), 0);
+}
+
+// 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;
+  xTimerChangePeriod(blinky_tm, pdMS_TO_TICKS(BLINK_SUSPENDED), 0);
+}
+
+// Invoked when usb bus is resumed
+void tud_resume_cb(void)
+{
+  xTimerChangePeriod(blinky_tm, pdMS_TO_TICKS(BLINK_MOUNTED), 0);
+}
+
+//--------------------------------------------------------------------+
+// 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;
+  (void) pBuff;
+
+  // 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);
+
+  (void) channelNum; (void) ctrlSel; (void) ep;
+
+  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;
+  (void) pBuff;
+
+  // 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);
+
+  (void) channelNum; (void) ctrlSel; (void) itf;
+
+  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);
+
+  (void) itf;
+
+  // 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);
+
+  (void) channelNum; (void) ctrlSel; (void) ep;
+
+  //	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);
+
+  (void) channelNum; (void) ctrlSel; (void) itf;
+
+  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));
+      }
+      break;
+
+        // 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;
+        }
+      break;
+
+        // 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;
+        }
+      break;
+
+      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
+}
+
+bool tud_audio_tx_done_pre_load_cb(uint8_t rhport, uint8_t itf, uint8_t ep_in, uint8_t cur_alt_setting)
+{
+  (void) rhport;
+  (void) itf;
+  (void) ep_in;
+  (void) cur_alt_setting;
+
+  tud_audio_write ((uint8_t *)test_buffer_audio, CFG_TUD_AUDIO_EP_SZ_IN);
+
+  return true;
+}
+
+bool tud_audio_tx_done_post_load_cb(uint8_t rhport, uint16_t n_bytes_copied, uint8_t itf, uint8_t ep_in, uint8_t cur_alt_setting)
+{
+  (void) rhport;
+  (void) n_bytes_copied;
+  (void) itf;
+  (void) ep_in;
+  (void) cur_alt_setting;
+
+  for (size_t cnt = 0; cnt < CFG_TUD_AUDIO_EP_SZ_IN/2; cnt++)
+  {
+    test_buffer_audio[cnt] = startVal++;
+  }
+
+  return true;
+}
+
+bool tud_audio_set_itf_close_EP_cb(uint8_t rhport, tusb_control_request_t const * p_request)
+{
+  (void) rhport;
+  (void) p_request;
+  startVal = 0;
+
+  return true;
+}
+
+///--------------------------------------------------------------------+
+// BLINKING TASK
+//--------------------------------------------------------------------+
+void led_blinky_cb(TimerHandle_t xTimer)
+{
+  (void) xTimer;
+  static bool led_state = false;
+
+  board_led_write(led_state);
+  led_state = 1 - led_state; // toggle
+}
diff --git a/examples/device/audio_test_freertos/src/plot_audio_samples.py b/examples/device/audio_test_freertos/src/plot_audio_samples.py
new file mode 100644
index 000000000..6e3c4978e
--- /dev/null
+++ b/examples/device/audio_test_freertos/src/plot_audio_samples.py
@@ -0,0 +1,34 @@
+import sounddevice as sd
+import matplotlib.pyplot as plt
+import numpy as np
+import platform
+
+if __name__ == '__main__':
+
+    # If you got "ValueError: No input device matching", that is because your PC name example device
+    # differently from tested list below. Uncomment the next line to see full list and try to pick correct one
+    # print(sd.query_devices())
+
+    fs = 48000           # Sample rate
+    duration = 100e-3    # Duration of recording
+
+    if platform.system() == 'Windows':
+        # MME is needed since there are more than one MicNode device APIs (at least in Windows)
+        device = 'Microphone (MicNode) MME'
+    elif platform.system() == 'Darwin':
+        device = 'MicNode'
+    else:
+        device ='default'
+
+    myrecording = sd.rec(int(duration * fs), samplerate=fs, channels=1, dtype='int16', device=device)
+    print('Waiting...')
+    sd.wait()  # Wait until recording is finished
+    print('Done!')
+
+    time = np.arange(0, duration, 1 / fs)  # time vector
+    plt.plot(time, myrecording)
+    plt.xlabel('Time [s]')
+    plt.ylabel('Amplitude')
+    plt.title('MicNode')
+    plt.show()
+    
\ No newline at end of file
diff --git a/examples/device/audio_test_freertos/src/tusb_config.h b/examples/device/audio_test_freertos/src/tusb_config.h
new file mode 100644
index 000000000..598706e78
--- /dev/null
+++ b/examples/device/audio_test_freertos/src/tusb_config.h
@@ -0,0 +1,121 @@
+/*
+ * 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
+
+// RHPort number used for device can be defined by board.mk, default to port 0
+#ifndef BOARD_DEVICE_RHPORT_NUM
+  #define BOARD_DEVICE_RHPORT_NUM     0
+#endif
+
+#ifndef BOARD_DEVICE_RHPORT_SPEED
+  #define BOARD_DEVICE_RHPORT_SPEED   OPT_MODE_FULL_SPEED
+#endif
+
+#define CFG_TUSB_RHPORT0_MODE       OPT_MODE_DEVICE
+
+#ifndef CFG_TUSB_OS
+  #define CFG_TUSB_OS                 OPT_OS_FREERTOS
+#endif
+
+// Espressif IDF requires "freertos/" prefix in include path
+#if TU_CHECK_MCU(OPT_MCU_ESP32S2, OPT_MCU_ESP32S3)
+  #define CFG_TUSB_OS_INC_PATH    freertos/
+#endif
+
+#ifndef CFG_TUSB_DEBUG
+  #define CFG_TUSB_DEBUG              0
+#endif
+
+// 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
+//--------------------------------------------------------------------
+
+// Have a look into audio_device.h for all configurations
+
+#define CFG_TUD_AUDIO_FUNC_1_DESC_LEN                                 TUD_AUDIO_MIC_ONE_CH_DESC_LEN
+#define CFG_TUD_AUDIO_FUNC_1_N_AS_INT                                 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_CTRL_BUF_SZ                              64                                      // Size of control request buffer
+
+#define CFG_TUD_AUDIO_ENABLE_EP_IN                                    1
+#define CFG_TUD_AUDIO_FUNC_1_N_BYTES_PER_SAMPLE_TX                    2                                       // Driver gets this info from the descriptors - we define it here to use it to setup the descriptors and to do calculations with it below
+#define CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_TX                            1                                       // Driver gets this info from the descriptors - we define it here to use it to setup the descriptors and to do calculations with it below - be aware: for different number of channels you need another descriptor!
+#define CFG_TUD_AUDIO_EP_SZ_IN                                        48 * CFG_TUD_AUDIO_FUNC_1_N_BYTES_PER_SAMPLE_TX * CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_TX      // 48 Samples (48 kHz) x 2 Bytes/Sample x 1 Channel
+#define CFG_TUD_AUDIO_FUNC_1_EP_IN_SZ_MAX                             CFG_TUD_AUDIO_EP_SZ_IN                  // Maximum EP IN size for all AS alternate settings used
+#define CFG_TUD_AUDIO_FUNC_1_EP_IN_SW_BUF_SZ                          CFG_TUD_AUDIO_EP_SZ_IN + 1
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _TUSB_CONFIG_H_ */
diff --git a/examples/device/audio_test_freertos/src/usb_descriptors.c b/examples/device/audio_test_freertos/src/usb_descriptors.c
new file mode 100644
index 000000000..b8df75e71
--- /dev/null
+++ b/examples/device/audio_test_freertos/src/usb_descriptors.c
@@ -0,0 +1,165 @@
+/*
+ * 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_ONE_CH_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
+
+#elif TU_CHECK_MCU(OPT_MCU_NRF5X)
+  // nRF5x ISO can only be endpoint 8
+  #define EPNUM_AUDIO   0x08
+
+#else
+  #define EPNUM_AUDIO   0x01
+#endif
+
+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, 0x00, 100),
+
+  // Interface number, string index, EP Out & EP In address, EP size
+  TUD_AUDIO_MIC_ONE_CH_DESCRIPTOR(/*_itfnum*/ ITF_NUM_AUDIO_CONTROL, /*_stridx*/ 0, /*_nBytesPerSample*/ CFG_TUD_AUDIO_FUNC_1_N_BYTES_PER_SAMPLE_TX, /*_nBitsUsedPerSample*/ CFG_TUD_AUDIO_FUNC_1_N_BYTES_PER_SAMPLE_TX*8, /*_epin*/ 0x80 | EPNUM_AUDIO, /*_epsize*/ CFG_TUD_AUDIO_EP_SZ_IN)
+};
+
+// 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;
+}