Merge branch 'master' into nxp_k64

64 files changed, 2193 insertions, 666 deletions

diff --git a/examples/device/CMakeLists.txt b/examples/device/CMakeLists.txt
index 5b077a5e1..0a2e49ef0 100644
--- a/examples/device/CMakeLists.txt
+++ b/examples/device/CMakeLists.txt
@@ -13,9 +13,11 @@ family_add_subdirectory(board_test)
 family_add_subdirectory(cdc_dual_ports)
 family_add_subdirectory(cdc_msc)
 family_add_subdirectory(cdc_msc_freertos)
+family_add_subdirectory(cdc_uac2)
 family_add_subdirectory(dfu)
 family_add_subdirectory(dfu_runtime)
 family_add_subdirectory(dynamic_configuration)
+family_add_subdirectory(hid_boot_interface)
 family_add_subdirectory(hid_composite)
 family_add_subdirectory(hid_composite_freertos)
 family_add_subdirectory(hid_generic_inout)
diff --git a/examples/device/audio_4_channel_mic/src/main.c b/examples/device/audio_4_channel_mic/src/main.c
index 2b9c5143d..94ac86d84 100644
--- a/examples/device/audio_4_channel_mic/src/main.c
+++ b/examples/device/audio_4_channel_mic/src/main.c
@@ -35,7 +35,7 @@
 #include <stdio.h>
 #include <string.h>
 
-#include "bsp/board.h"
+#include "bsp/board_api.h"
 #include "tusb.h"
 
 //--------------------------------------------------------------------+
@@ -84,6 +84,10 @@ int main(void)
   // init device stack on configured roothub port
   tud_init(BOARD_TUD_RHPORT);
 
+  if (board_init_after_tusb) {
+    board_init_after_tusb();
+  }
+
   // Init values
   sampFreq = AUDIO_SAMPLE_RATE;
   clkValid = 1;
@@ -129,7 +133,7 @@ void tud_suspend_cb(bool remote_wakeup_en)
 // Invoked when usb bus is resumed
 void tud_resume_cb(void)
 {
-  blink_interval_ms = BLINK_MOUNTED;
+  blink_interval_ms = tud_mounted() ? BLINK_MOUNTED : BLINK_NOT_MOUNTED;
 }
 
 //--------------------------------------------------------------------+
diff --git a/examples/device/audio_4_channel_mic/src/usb_descriptors.c b/examples/device/audio_4_channel_mic/src/usb_descriptors.c
index b77da9fac..728a5f9ce 100644
--- a/examples/device/audio_4_channel_mic/src/usb_descriptors.c
+++ b/examples/device/audio_4_channel_mic/src/usb_descriptors.c
@@ -23,6 +23,7 @@
  *
  */
 
+#include "bsp/board_api.h"
 #include "tusb.h"
 
 /* A combination of interfaces must have a unique product id, since PC will save device driver after the first plug.
@@ -116,50 +117,63 @@ uint8_t const * tud_descriptor_configuration_cb(uint8_t index)
 // 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)
-    "PaniRCorp",                   	// 1: Manufacturer
-    "MicNode_4_Ch",    		// 2: Product
-    "123458",                      	// 3: Serials, should use chip ID
-    "UAC2",                 	 	// 4: Audio Interface
+char const* string_desc_arr [] = {
+    (const char[]) { 0x09, 0x04 }, // 0: is supported language is English (0x0409)
+    "PaniRCorp",                   // 1: Manufacturer
+    "MicNode_4_Ch",                // 2: Product
+    NULL,                          // 3: Serials will use unique ID if possible
+    "UAC2",                        // 4: Audio Interface
 };
 
-static uint16_t _desc_str[32];
+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)
-{
+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;
 
-  uint8_t chr_count;
+    case STRID_SERIAL:
+      chr_count = board_usb_get_serial(_desc_str + 1, 32);
+      break;
 
-  if ( index == 0)
-  {
-    memcpy(&_desc_str[1], string_desc_arr[0], 2);
-    chr_count = 1;
-  }else
-  {
-    // Convert ASCII string into UTF-16
+    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;
+      if ( !(index < sizeof(string_desc_arr) / sizeof(string_desc_arr[0])) ) return NULL;
 
-    const char* str = string_desc_arr[index];
+      const char *str = string_desc_arr[index];
 
-    // Cap at max char
-    chr_count = (uint8_t) strlen(str);
-    if ( chr_count > 31 ) chr_count = 31;
+      // 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;
 
-    for(uint8_t i=0; i<chr_count; i++)
-    {
-      _desc_str[1+i] = str[i];
-    }
+      // 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));
+  _desc_str[0] = (uint16_t) ((TUSB_DESC_STRING << 8) | (2 * chr_count + 2));
 
   return _desc_str;
 }
diff --git a/examples/device/audio_test/src/main.c b/examples/device/audio_test/src/main.c
index b5ca41d36..06783ccfb 100644
--- a/examples/device/audio_test/src/main.c
+++ b/examples/device/audio_test/src/main.c
@@ -35,7 +35,7 @@
 #include <stdio.h>
 #include <string.h>
 
-#include "bsp/board.h"
+#include "bsp/board_api.h"
 #include "tusb.h"
 
 //--------------------------------------------------------------------+
@@ -85,6 +85,10 @@ int main(void)
   // init device stack on configured roothub port
   tud_init(BOARD_TUD_RHPORT);
 
+  if (board_init_after_tusb) {
+    board_init_after_tusb();
+  }
+
   // Init values
   sampFreq = AUDIO_SAMPLE_RATE;
   clkValid = 1;
@@ -130,7 +134,7 @@ void tud_suspend_cb(bool remote_wakeup_en)
 // Invoked when usb bus is resumed
 void tud_resume_cb(void)
 {
-  blink_interval_ms = BLINK_MOUNTED;
+  blink_interval_ms = tud_mounted() ? BLINK_MOUNTED : BLINK_NOT_MOUNTED;
 }
 
 //--------------------------------------------------------------------+
diff --git a/examples/device/audio_test/src/usb_descriptors.c b/examples/device/audio_test/src/usb_descriptors.c
index cc364ee88..9864377f6 100644
--- a/examples/device/audio_test/src/usb_descriptors.c
+++ b/examples/device/audio_test/src/usb_descriptors.c
@@ -23,6 +23,7 @@
  *
  */
 
+#include "bsp/board_api.h"
 #include "tusb.h"
 
 /* A combination of interfaces must have a unique product id, since PC will save device driver after the first plug.
@@ -116,50 +117,65 @@ uint8_t const * tud_descriptor_configuration_cb(uint8_t index)
 // 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)
-    "PaniRCorp",                   	// 1: Manufacturer
-    "MicNode",              		// 2: Product
-    "123456",                      	// 3: Serials, should use chip ID
-    "UAC2",                 	 	// 4: Audio Interface
+    (const char[]) { 0x09, 0x04 }, // 0: is supported language is English (0x0409)
+    "PaniRCorp",                   // 1: Manufacturer
+    "MicNode",                     // 2: Product
+    NULL,                          // 3: Serials will use unique ID if possible
+    "UAC2",                        // 4: Audio Interface
+
 };
 
-static uint16_t _desc_str[32];
+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)
-{
+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;
 
-  uint8_t chr_count;
+    case STRID_SERIAL:
+      chr_count = board_usb_get_serial(_desc_str + 1, 32);
+      break;
 
-  if ( index == 0)
-  {
-    memcpy(&_desc_str[1], string_desc_arr[0], 2);
-    chr_count = 1;
-  }else
-  {
-    // Convert ASCII string into UTF-16
+    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;
+      if ( !(index < sizeof(string_desc_arr) / sizeof(string_desc_arr[0])) ) return NULL;
 
-    const char* str = string_desc_arr[index];
+      const char *str = string_desc_arr[index];
 
-    // Cap at max char
-    chr_count = (uint8_t) strlen(str);
-    if ( chr_count > 31 ) chr_count = 31;
+      // 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;
 
-    for(uint8_t i=0; i<chr_count; i++)
-    {
-      _desc_str[1+i] = str[i];
-    }
+      // 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));
+  _desc_str[0] = (uint16_t) ((TUSB_DESC_STRING << 8) | (2 * chr_count + 2));
 
   return _desc_str;
 }
diff --git a/examples/device/audio_test_multi_rate/src/main.c b/examples/device/audio_test_multi_rate/src/main.c
index 078e783eb..3e7f40dac 100644
--- a/examples/device/audio_test_multi_rate/src/main.c
+++ b/examples/device/audio_test_multi_rate/src/main.c
@@ -36,7 +36,7 @@
 #include <stdio.h>
 #include <string.h>
 
-#include "bsp/board.h"
+#include "bsp/board_api.h"
 #include "tusb.h"
 #include "usb_descriptors.h"
 
@@ -99,6 +99,10 @@ int main(void)
   // init device stack on configured roothub port
   tud_init(BOARD_TUD_RHPORT);
 
+  if (board_init_after_tusb) {
+    board_init_after_tusb();
+  }
+
   // Init values
   sampFreq = sampleRatesList[0];
   clkValid = 1;
@@ -142,7 +146,7 @@ void tud_suspend_cb(bool remote_wakeup_en)
 // Invoked when usb bus is resumed
 void tud_resume_cb(void)
 {
-  blink_interval_ms = BLINK_MOUNTED;
+  blink_interval_ms = tud_mounted() ? BLINK_MOUNTED : BLINK_NOT_MOUNTED;
 }
 
 //--------------------------------------------------------------------+
diff --git a/examples/device/audio_test_multi_rate/src/usb_descriptors.c b/examples/device/audio_test_multi_rate/src/usb_descriptors.c
index 2c72edb17..f50e70a25 100644
--- a/examples/device/audio_test_multi_rate/src/usb_descriptors.c
+++ b/examples/device/audio_test_multi_rate/src/usb_descriptors.c
@@ -24,6 +24,7 @@
  *
  */
 
+#include "bsp/board_api.h"
 #include "tusb.h"
 #include "usb_descriptors.h"
 
@@ -120,50 +121,65 @@ uint8_t const * tud_descriptor_configuration_cb(uint8_t index)
 // 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)
-    "PaniRCorp",                   	// 1: Manufacturer
-    "MicNode",              		// 2: Product
-    "123456",                      	// 3: Serials, should use chip ID
-    "UAC2",                 	 	// 4: Audio Interface
+    (const char[]) { 0x09, 0x04 }, // 0: is supported language is English (0x0409)
+    "PaniRCorp",                   // 1: Manufacturer
+    "MicNode",                     // 2: Product
+    NULL,                          // 3: Serials will use unique ID if possible
+    "UAC2",                        // 4: Audio Interface
+
 };
 
-static uint16_t _desc_str[32];
+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)
-{
+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;
 
-  uint8_t chr_count;
+    case STRID_SERIAL:
+      chr_count = board_usb_get_serial(_desc_str + 1, 32);
+      break;
 
-  if ( index == 0)
-  {
-    memcpy(&_desc_str[1], string_desc_arr[0], 2);
-    chr_count = 1;
-  }else
-  {
-    // Convert ASCII string into UTF-16
+    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;
+      if ( !(index < sizeof(string_desc_arr) / sizeof(string_desc_arr[0])) ) return NULL;
 
-    const char* str = string_desc_arr[index];
+      const char *str = string_desc_arr[index];
 
-    // Cap at max char
-    chr_count = (uint8_t) strlen(str);
-    if ( chr_count > 31 ) chr_count = 31;
+      // 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;
 
-    for(uint8_t i=0; i<chr_count; i++)
-    {
-      _desc_str[1+i] = str[i];
-    }
+      // 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));
+  _desc_str[0] = (uint16_t) ((TUSB_DESC_STRING << 8) | (2 * chr_count + 2));
 
   return _desc_str;
 }
diff --git a/examples/device/board_test/src/main.c b/examples/device/board_test/src/main.c
index b11f6f2bb..0a134a2e6 100644
--- a/examples/device/board_test/src/main.c
+++ b/examples/device/board_test/src/main.c
@@ -27,7 +27,7 @@
 #include <stdio.h>
 #include <string.h>
 
-#include "bsp/board.h"
+#include "bsp/board_api.h"
 
 //--------------------------------------------------------------------+
 // MACRO CONSTANT TYPEDEF PROTOTYPES
diff --git a/examples/device/cdc_dual_ports/src/main.c b/examples/device/cdc_dual_ports/src/main.c
index 70eaea85d..98f3ab923 100644
--- a/examples/device/cdc_dual_ports/src/main.c
+++ b/examples/device/cdc_dual_ports/src/main.c
@@ -28,7 +28,7 @@
 #include <string.h>
 #include <ctype.h>
 
-#include "bsp/board.h"
+#include "bsp/board_api.h"
 #include "tusb.h"
 
 //------------- prototypes -------------//
@@ -42,6 +42,10 @@ int main(void)
   // init device stack on configured roothub port
   tud_init(BOARD_TUD_RHPORT);
 
+  if (board_init_after_tusb) {
+    board_init_after_tusb();
+  }
+
   while (1)
   {
     tud_task(); // tinyusb device task
diff --git a/examples/device/cdc_dual_ports/src/usb_descriptors.c b/examples/device/cdc_dual_ports/src/usb_descriptors.c
index 8be404cc9..de2505c07 100644
--- a/examples/device/cdc_dual_ports/src/usb_descriptors.c
+++ b/examples/device/cdc_dual_ports/src/usb_descriptors.c
@@ -23,13 +23,14 @@
  *
  */
 
+#include "bsp/board_api.h"
 #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]       MIDI | HID | MSC | CDC          [LSB]
+ *   [MSB]         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) | \
@@ -213,52 +214,64 @@ uint8_t const * tud_descriptor_configuration_cb(uint8_t index)
 // 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 [] =
+char const *string_desc_arr[] =
 {
   (const char[]) { 0x09, 0x04 }, // 0: is supported language is English (0x0409)
   "TinyUSB",                     // 1: Manufacturer
   "TinyUSB Device",              // 2: Product
-  "123456",                      // 3: Serials, should use chip ID
+  NULL,                          // 3: Serials will use unique ID if possible
   "TinyUSB CDC",                 // 4: CDC Interface
 };
 
-static uint16_t _desc_str[32];
+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)
-{
+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;
 
-  uint8_t chr_count;
+    case STRID_SERIAL:
+      chr_count = board_usb_get_serial(_desc_str + 1, 32);
+      break;
 
-  if ( index == 0)
-  {
-    memcpy(&_desc_str[1], string_desc_arr[0], 2);
-    chr_count = 1;
-  }else
-  {
-    // 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
+    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;
+      if ( !(index < sizeof(string_desc_arr) / sizeof(string_desc_arr[0])) ) return NULL;
 
-    const char* str = string_desc_arr[index];
+      const char *str = string_desc_arr[index];
 
-    // Cap at max char
-    chr_count = (uint8_t) strlen(str);
-    if ( chr_count > 31 ) chr_count = 31;
+      // 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(uint8_t i=0; i<chr_count; i++)
-    {
-      _desc_str[1+i] = str[i];
-    }
+      // 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));
+  _desc_str[0] = (uint16_t) ((TUSB_DESC_STRING << 8) | (2 * chr_count + 2));
 
   return _desc_str;
 }
diff --git a/examples/device/cdc_msc/src/main.c b/examples/device/cdc_msc/src/main.c
index 6dad73cbf..172f48ae0 100644
--- a/examples/device/cdc_msc/src/main.c
+++ b/examples/device/cdc_msc/src/main.c
@@ -27,7 +27,7 @@
 #include <stdio.h>
 #include <string.h>
 
-#include "bsp/board.h"
+#include "bsp/board_api.h"
 #include "tusb.h"
 
 //--------------------------------------------------------------------+
@@ -58,6 +58,10 @@ int main(void)
   // init device stack on configured roothub port
   tud_init(BOARD_TUD_RHPORT);
 
+  if (board_init_after_tusb) {
+    board_init_after_tusb();
+  }
+
   while (1)
   {
     tud_task(); // tinyusb device task
@@ -95,7 +99,7 @@ void tud_suspend_cb(bool remote_wakeup_en)
 // Invoked when usb bus is resumed
 void tud_resume_cb(void)
 {
-  blink_interval_ms = BLINK_MOUNTED;
+  blink_interval_ms = tud_mounted() ? BLINK_MOUNTED : BLINK_NOT_MOUNTED;
 }
 
 
diff --git a/examples/device/cdc_msc/src/msc_disk.c b/examples/device/cdc_msc/src/msc_disk.c
index f8f37a577..d2f8628f1 100644
--- a/examples/device/cdc_msc/src/msc_disk.c
+++ b/examples/device/cdc_msc/src/msc_disk.c
@@ -23,7 +23,7 @@
  *
  */
 
-#include "bsp/board.h"
+#include "bsp/board_api.h"
 #include "tusb.h"
 
 #if CFG_TUD_MSC
diff --git a/examples/device/cdc_msc/src/usb_descriptors.c b/examples/device/cdc_msc/src/usb_descriptors.c
index 44c849277..2afa24903 100644
--- a/examples/device/cdc_msc/src/usb_descriptors.c
+++ b/examples/device/cdc_msc/src/usb_descriptors.c
@@ -23,6 +23,7 @@
  *
  */
 
+#include "bsp/board_api.h"
 #include "tusb.h"
 
 /* A combination of interfaces must have a unique product id, since PC will save device driver after the first plug.
@@ -41,35 +42,33 @@
 //--------------------------------------------------------------------+
 // Device Descriptors
 //--------------------------------------------------------------------+
-tusb_desc_device_t const desc_device =
-{
-  .bLength            = sizeof(tusb_desc_device_t),
-  .bDescriptorType    = TUSB_DESC_DEVICE,
-  .bcdUSB             = USB_BCD,
+tusb_desc_device_t const desc_device = {
+    .bLength            = sizeof(tusb_desc_device_t),
+    .bDescriptorType    = TUSB_DESC_DEVICE,
+    .bcdUSB             = USB_BCD,
 
-  // 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,
+    // 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,
+    .bMaxPacketSize0    = CFG_TUD_ENDPOINT0_SIZE,
 
-  .idVendor           = USB_VID,
-  .idProduct          = USB_PID,
-  .bcdDevice          = 0x0100,
+    .idVendor           = USB_VID,
+    .idProduct          = USB_PID,
+    .bcdDevice          = 0x0100,
 
-  .iManufacturer      = 0x01,
-  .iProduct           = 0x02,
-  .iSerialNumber      = 0x03,
+    .iManufacturer      = 0x01,
+    .iProduct           = 0x02,
+    .iSerialNumber      = 0x03,
 
-  .bNumConfigurations = 0x01
+    .bNumConfigurations = 0x01
 };
 
 // Invoked when received GET DEVICE DESCRIPTOR
 // Application return pointer to descriptor
-uint8_t const * tud_descriptor_device_cb(void)
-{
+uint8_t const *tud_descriptor_device_cb(void) {
   return (uint8_t const *) &desc_device;
 }
 
@@ -77,8 +76,7 @@ uint8_t const * tud_descriptor_device_cb(void)
 // Configuration Descriptor
 //--------------------------------------------------------------------+
 
-enum
-{
+enum {
   ITF_NUM_CDC = 0,
   ITF_NUM_CDC_DATA,
   ITF_NUM_MSC,
@@ -95,7 +93,7 @@ enum
   #define EPNUM_MSC_OUT     0x05
   #define EPNUM_MSC_IN      0x85
 
-#elif CFG_TUSB_MCU == OPT_MCU_SAMG  || CFG_TUSB_MCU ==  OPT_MCU_SAMX7X
+#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_CDC_NOTIF   0x81
@@ -140,67 +138,62 @@ enum
 #define CONFIG_TOTAL_LEN    (TUD_CONFIG_DESC_LEN + TUD_CDC_DESC_LEN + TUD_MSC_DESC_LEN)
 
 // full speed configuration
-uint8_t const desc_fs_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),
+uint8_t const desc_fs_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, EP notification address and size, EP data address (out, in) and size.
-  TUD_CDC_DESCRIPTOR(ITF_NUM_CDC, 4, EPNUM_CDC_NOTIF, 8, EPNUM_CDC_OUT, EPNUM_CDC_IN, 64),
+    // Interface number, string index, EP notification address and size, EP data address (out, in) and size.
+    TUD_CDC_DESCRIPTOR(ITF_NUM_CDC, 4, EPNUM_CDC_NOTIF, 8, EPNUM_CDC_OUT, EPNUM_CDC_IN, 64),
 
-  // Interface number, string index, EP Out & EP In address, EP size
-  TUD_MSC_DESCRIPTOR(ITF_NUM_MSC, 5, EPNUM_MSC_OUT, EPNUM_MSC_IN, 64),
+    // Interface number, string index, EP Out & EP In address, EP size
+    TUD_MSC_DESCRIPTOR(ITF_NUM_MSC, 5, EPNUM_MSC_OUT, EPNUM_MSC_IN, 64),
 };
 
 #if TUD_OPT_HIGH_SPEED
 // Per USB specs: high speed capable device must report device_qualifier and other_speed_configuration
 
 // high speed configuration
-uint8_t const desc_hs_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),
+uint8_t const desc_hs_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, EP notification address and size, EP data address (out, in) and size.
-  TUD_CDC_DESCRIPTOR(ITF_NUM_CDC, 4, EPNUM_CDC_NOTIF, 8, EPNUM_CDC_OUT, EPNUM_CDC_IN, 512),
+    // Interface number, string index, EP notification address and size, EP data address (out, in) and size.
+    TUD_CDC_DESCRIPTOR(ITF_NUM_CDC, 4, EPNUM_CDC_NOTIF, 8, EPNUM_CDC_OUT, EPNUM_CDC_IN, 512),
 
-  // Interface number, string index, EP Out & EP In address, EP size
-  TUD_MSC_DESCRIPTOR(ITF_NUM_MSC, 5, EPNUM_MSC_OUT, EPNUM_MSC_IN, 512),
+    // Interface number, string index, EP Out & EP In address, EP size
+    TUD_MSC_DESCRIPTOR(ITF_NUM_MSC, 5, EPNUM_MSC_OUT, EPNUM_MSC_IN, 512),
 };
 
 // other speed configuration
 uint8_t desc_other_speed_config[CONFIG_TOTAL_LEN];
 
 // device qualifier is mostly similar to device descriptor since we don't change configuration based on speed
-tusb_desc_device_qualifier_t const desc_device_qualifier =
-{
-  .bLength            = sizeof(tusb_desc_device_qualifier_t),
-  .bDescriptorType    = TUSB_DESC_DEVICE_QUALIFIER,
-  .bcdUSB             = USB_BCD,
+tusb_desc_device_qualifier_t const desc_device_qualifier = {
+    .bLength            = sizeof(tusb_desc_device_qualifier_t),
+    .bDescriptorType    = TUSB_DESC_DEVICE_QUALIFIER,
+    .bcdUSB             = USB_BCD,
 
-  .bDeviceClass       = TUSB_CLASS_MISC,
-  .bDeviceSubClass    = MISC_SUBCLASS_COMMON,
-  .bDeviceProtocol    = MISC_PROTOCOL_IAD,
+    .bDeviceClass       = TUSB_CLASS_MISC,
+    .bDeviceSubClass    = MISC_SUBCLASS_COMMON,
+    .bDeviceProtocol    = MISC_PROTOCOL_IAD,
 
-  .bMaxPacketSize0    = CFG_TUD_ENDPOINT0_SIZE,
-  .bNumConfigurations = 0x01,
-  .bReserved          = 0x00
+    .bMaxPacketSize0    = CFG_TUD_ENDPOINT0_SIZE,
+    .bNumConfigurations = 0x01,
+    .bReserved          = 0x00
 };
 
 // Invoked when received GET DEVICE QUALIFIER DESCRIPTOR request
 // Application return pointer to descriptor, whose contents must exist long enough for transfer to complete.
 // device_qualifier descriptor describes information about a high-speed capable device that would
 // change if the device were operating at the other speed. If not highspeed capable stall this request.
-uint8_t const* tud_descriptor_device_qualifier_cb(void)
-{
-  return (uint8_t const*) &desc_device_qualifier;
+uint8_t const *tud_descriptor_device_qualifier_cb(void) {
+  return (uint8_t const *) &desc_device_qualifier;
 }
 
 // Invoked when received GET OTHER SEED CONFIGURATION DESCRIPTOR request
 // Application return pointer to descriptor, whose contents must exist long enough for transfer to complete
 // Configuration descriptor in the other speed e.g if high speed then this is for full speed and vice versa
-uint8_t const* tud_descriptor_other_speed_configuration_cb(uint8_t index)
-{
+uint8_t const *tud_descriptor_other_speed_configuration_cb(uint8_t index) {
   (void) index; // for multiple configurations
 
   // if link speed is high return fullspeed config, and vice versa
@@ -220,13 +213,12 @@ uint8_t const* tud_descriptor_other_speed_configuration_cb(uint8_t index)
 // 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)
-{
+uint8_t const *tud_descriptor_configuration_cb(uint8_t index) {
   (void) index; // for multiple configurations
 
 #if TUD_OPT_HIGH_SPEED
   // Although we are highspeed, host may be fullspeed.
-  return (tud_speed_get() == TUSB_SPEED_HIGH) ?  desc_hs_configuration : desc_fs_configuration;
+  return (tud_speed_get() == TUSB_SPEED_HIGH) ? desc_hs_configuration : desc_fs_configuration;
 #else
   return desc_fs_configuration;
 #endif
@@ -236,53 +228,64 @@ uint8_t const * tud_descriptor_configuration_cb(uint8_t index)
 // 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 Device",              // 2: Product
-  "123456789012",                // 3: Serials, should use chip ID
-  "TinyUSB CDC",                 // 4: CDC Interface
-  "TinyUSB MSC",                 // 5: MSC Interface
+char const *string_desc_arr[] = {
+    (const char[]) { 0x09, 0x04 }, // 0: is supported language is English (0x0409)
+    "TinyUSB",                     // 1: Manufacturer
+    "TinyUSB Device",              // 2: Product
+    NULL,                          // 3: Serials will use unique ID if possible
+    "TinyUSB CDC",                 // 4: CDC Interface
+    "TinyUSB MSC",                 // 5: MSC Interface
 };
 
-static uint16_t _desc_str[32];
+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)
-{
+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;
 
-  uint8_t chr_count;
+    case STRID_SERIAL:
+      chr_count = board_usb_get_serial(_desc_str + 1, 32);
+      break;
 
-  if ( index == 0)
-  {
-    memcpy(&_desc_str[1], string_desc_arr[0], 2);
-    chr_count = 1;
-  }else
-  {
-    // 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
+    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;
+      if ( !(index < sizeof(string_desc_arr) / sizeof(string_desc_arr[0])) ) return NULL;
 
-    const char* str = string_desc_arr[index];
+      const char *str = string_desc_arr[index];
 
-    // Cap at max char
-    chr_count = (uint8_t) strlen(str);
-    if ( chr_count > 31 ) chr_count = 31;
+      // 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(uint8_t i=0; i<chr_count; i++)
-    {
-      _desc_str[1+i] = str[i];
-    }
+      // 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));
+  _desc_str[0] = (uint16_t) ((TUSB_DESC_STRING << 8) | (2 * chr_count + 2));
 
   return _desc_str;
 }
diff --git a/examples/device/cdc_msc_freertos/skip.txt b/examples/device/cdc_msc_freertos/skip.txt
index 49b8ee57b..a6f96b288 100644
--- a/examples/device/cdc_msc_freertos/skip.txt
+++ b/examples/device/cdc_msc_freertos/skip.txt
@@ -8,5 +8,6 @@ mcu:RP2040
 mcu:SAMD11
 mcu:SAMX7X
 mcu:VALENTYUSB_EPTRI
+mcu:RAXXX
 family:broadcom_32bit
 family:broadcom_64bit
diff --git a/examples/device/cdc_msc_freertos/src/FreeRTOSConfig/FreeRTOSConfig.h b/examples/device/cdc_msc_freertos/src/FreeRTOSConfig/FreeRTOSConfig.h
index 9bef9bbbf..69d638288 100644
--- a/examples/device/cdc_msc_freertos/src/FreeRTOSConfig/FreeRTOSConfig.h
+++ b/examples/device/cdc_msc_freertos/src/FreeRTOSConfig/FreeRTOSConfig.h
@@ -81,7 +81,7 @@
 #define configUSE_MUTEXES                       1
 #define configUSE_RECURSIVE_MUTEXES             1
 #define configUSE_COUNTING_SEMAPHORES           1
-#define configQUEUE_REGISTRY_SIZE               2
+#define configQUEUE_REGISTRY_SIZE               4
 #define configUSE_QUEUE_SETS                    0
 #define configUSE_TIME_SLICING                  0
 #define configUSE_NEWLIB_REENTRANT              0
diff --git a/examples/device/cdc_msc_freertos/src/main.c b/examples/device/cdc_msc_freertos/src/main.c
index 0e8a24d02..0b115a595 100644
--- a/examples/device/cdc_msc_freertos/src/main.c
+++ b/examples/device/cdc_msc_freertos/src/main.c
@@ -27,7 +27,7 @@
 #include <stdio.h>
 #include <string.h>
 
-#include "bsp/board.h"
+#include "bsp/board_api.h"
 #include "tusb.h"
 
 #if TU_CHECK_MCU(OPT_MCU_ESP32S2, OPT_MCU_ESP32S3)
@@ -136,6 +136,10 @@ void usb_device_task(void* param)
   // Otherwise it could cause kernel issue since USB IRQ handler does use RTOS queue API.
   tud_init(BOARD_TUD_RHPORT);
 
+  if (board_init_after_tusb) {
+    board_init_after_tusb();
+  }
+
   // RTOS forever loop
   while (1)
   {
@@ -175,7 +179,14 @@ void tud_suspend_cb(bool remote_wakeup_en)
 // Invoked when usb bus is resumed
 void tud_resume_cb(void)
 {
-  xTimerChangePeriod(blinky_tm, pdMS_TO_TICKS(BLINK_MOUNTED), 0);
+  if (tud_mounted())
+  {
+    xTimerChangePeriod(blinky_tm, pdMS_TO_TICKS(BLINK_MOUNTED), 0);
+  }
+  else
+  {
+    xTimerChangePeriod(blinky_tm, pdMS_TO_TICKS(BLINK_NOT_MOUNTED), 0);
+  }
 }
 
 //--------------------------------------------------------------------+
diff --git a/examples/device/cdc_msc_freertos/src/msc_disk.c b/examples/device/cdc_msc_freertos/src/msc_disk.c
index 707c8d578..9520dfec1 100644
--- a/examples/device/cdc_msc_freertos/src/msc_disk.c
+++ b/examples/device/cdc_msc_freertos/src/msc_disk.c
@@ -23,7 +23,7 @@
  *
  */
 
-#include "bsp/board.h"
+#include "bsp/board_api.h"
 #include "tusb.h"
 
 #if CFG_TUD_MSC
diff --git a/examples/device/cdc_msc_freertos/src/usb_descriptors.c b/examples/device/cdc_msc_freertos/src/usb_descriptors.c
index 822442724..9c29701c7 100644
--- a/examples/device/cdc_msc_freertos/src/usb_descriptors.c
+++ b/examples/device/cdc_msc_freertos/src/usb_descriptors.c
@@ -23,6 +23,7 @@
  *
  */
 
+#include "bsp/board_api.h"
 #include "tusb.h"
 
 /* A combination of interfaces must have a unique product id, since PC will save device driver after the first plug.
@@ -212,53 +213,65 @@ uint8_t const * tud_descriptor_configuration_cb(uint8_t index)
 // 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 [] =
+char const *string_desc_arr[] =
 {
   (const char[]) { 0x09, 0x04 }, // 0: is supported language is English (0x0409)
   "TinyUSB",                     // 1: Manufacturer
   "TinyUSB Device",              // 2: Product
-  "123456789012",                // 3: Serials, should use chip ID
+  NULL,                          // 3: Serials will use unique ID if possible
   "TinyUSB CDC",                 // 4: CDC Interface
   "TinyUSB MSC",                 // 5: MSC Interface
 };
 
-static uint16_t _desc_str[32];
+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)
-{
+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;
 
-  uint8_t chr_count;
+    case STRID_SERIAL:
+      chr_count = board_usb_get_serial(_desc_str + 1, 32);
+      break;
 
-  if ( index == 0)
-  {
-    memcpy(&_desc_str[1], string_desc_arr[0], 2);
-    chr_count = 1;
-  }else
-  {
-    // 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
+    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;
+      if ( !(index < sizeof(string_desc_arr) / sizeof(string_desc_arr[0])) ) return NULL;
 
-    const char* str = string_desc_arr[index];
+      const char *str = string_desc_arr[index];
 
-    // Cap at max char
-    chr_count = (uint8_t) strlen(str);
-    if ( chr_count > 31 ) chr_count = 31;
+      // 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(uint8_t i=0; i<chr_count; i++)
-    {
-      _desc_str[1+i] = str[i];
-    }
+      // 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));
+  _desc_str[0] = (uint16_t) ((TUSB_DESC_STRING << 8) | (2 * chr_count + 2));
 
   return _desc_str;
 }
diff --git a/examples/device/cdc_uac2/CMakeLists.txt b/examples/device/cdc_uac2/CMakeLists.txt
new file mode 100644
index 000000000..64e4374e9
--- /dev/null
+++ b/examples/device/cdc_uac2/CMakeLists.txt
@@ -0,0 +1,38 @@
+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/cdc_app.c
+  ${CMAKE_CURRENT_SOURCE_DIR}/src/main.c
+  ${CMAKE_CURRENT_SOURCE_DIR}/src/uac2_app.c
+  ${CMAKE_CURRENT_SOURCE_DIR}/src/usb_descriptors.c
+  )
+
+# Example include
+target_include_directories(${PROJECT} PUBLIC
+  ${CMAKE_CURRENT_SOURCE_DIR}/src
+  )
+
+# Configure compilation flags and libraries for the example... see the corresponding function
+# in hw/bsp/FAMILY/family.cmake for details.
+family_configure_device_example(${PROJECT} noos)
+
+# Uncomment me to enable UART based debugging
+# pico_enable_stdio_uart(${PROJECT} 1)
diff --git a/examples/device/cdc_uac2/Makefile b/examples/device/cdc_uac2/Makefile
new file mode 100644
index 000000000..b7a8302ce
--- /dev/null
+++ b/examples/device/cdc_uac2/Makefile
@@ -0,0 +1,16 @@
+include ../../make.mk
+
+INC += \
+	src \
+	$(TOP)/hw \
+
+# Example source
+EXAMPLE_SOURCE += \
+  src/cdc_app.c \
+  src/main.c \
+  src/uac2_app.c \
+  src/usb_descriptors.c \
+
+SRC_C += $(addprefix $(CURRENT_PATH)/, $(EXAMPLE_SOURCE))
+
+include ../../rules.mk
diff --git a/examples/device/cdc_uac2/README.md b/examples/device/cdc_uac2/README.md
new file mode 100644
index 000000000..5d120be7d
--- /dev/null
+++ b/examples/device/cdc_uac2/README.md
@@ -0,0 +1,52 @@
+#### Composite CDC + UAC2 on Pico
+
+This example provides a composite CDC + UAC2 device on top of a Raspberry Pi
+Pico board.
+
+
+#### Use Cases
+
+- The CDC + UAC2 composite device happens to be important, especially in the
+  amateur radio community.
+
+  Modern radios (`rigs`) like Icom IC-7300 + IC-705 expose a sound card and a
+  serial device (`composite device`) to the computer over a single USB cable.
+  This allows for Audio I/O and CAT control over a single USB cable which is
+  very convenient.
+
+  By including and maintaining this example in TinyUSB repository, we enable
+  the amateur radio community to build (`homebrew`) radios with similar
+  functionality as the (expensive) commercial rigs.
+
+  This PR is important in bridging this specific gap between the commercial
+  rigs and homebrew equipment.
+
+- https://digirig.net/digirig-mobile-rev-1-9/ is a digital interface for
+  interfacing radios (that lack an inbuilt digital interface) with computers.
+  Digirig Mobile works brilliantly (is OSS!) and is a big improvement over
+  traditional digital interfaces (like the SignaLink USB Interface). By using a
+  Raspberry Pi Pico powered CDC + UAC2 composite device, we can simplify the
+  Digirig Mobile schematic, drastically reduce the manufacturing cost, and
+  (again) enable the homebrewers community to homebrew a modern digital interface
+  with ease themselves.
+
+
+#### Build Steps
+
+```
+cd examples/device/cdc_uac2
+
+export PICO_SDK_PATH=$HOME/pico-sdk
+
+cmake -DFAMILY=rp2040 pico .
+
+cmake -DFAMILY=rp2040 -DCMAKE_BUILD_TYPE=Debug # use this for debugging
+
+make BOARD=raspberry_pi_pico all
+```
+
+
+#### Development Notes
+
+Please try to keep this code synchronized with the `uac2_headset` example
+included in this repository.
diff --git a/examples/device/cdc_uac2/src/cdc_app.c b/examples/device/cdc_uac2/src/cdc_app.c
new file mode 100644
index 000000000..2166c1d6b
--- /dev/null
+++ b/examples/device/cdc_uac2/src/cdc_app.c
@@ -0,0 +1,72 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2019 Ha Thach (tinyusb.org)
+ * Copyright (c) 2022 Angel Molina ([email protected])
+ *
+ * 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 "common.h"
+
+// Invoked when cdc when line state changed e.g connected/disconnected
+void tud_cdc_line_state_cb(uint8_t itf, bool dtr, bool rts)
+{
+  (void) itf;
+  (void) rts;
+
+  if (dtr)
+  {
+    // Terminal connected
+  }
+  else
+  {
+    // Terminal disconnected
+  }
+}
+
+// Invoked when CDC interface received data from host
+void tud_cdc_rx_cb(uint8_t itf)
+{
+  uint8_t buf[64];
+  uint32_t count;
+
+  // connected() check for DTR bit
+  // Most but not all terminal client set this when making connection
+  if (tud_cdc_connected())
+  {
+    if (tud_cdc_available()) // data is available
+    {
+      count = tud_cdc_n_read(itf, buf, sizeof(buf));
+      (void) count;
+
+      tud_cdc_n_write(itf, buf, count);
+      tud_cdc_n_write_flush(itf);
+      // dummy code to check that cdc serial is responding
+      board_led_write(0);
+      board_delay(50);
+      board_led_write(1);
+      board_delay(50);
+      board_led_write(0);
+    }
+  }
+}
diff --git a/examples/device/cdc_uac2/src/common.h b/examples/device/cdc_uac2/src/common.h
new file mode 100644
index 000000000..f281024c7
--- /dev/null
+++ b/examples/device/cdc_uac2/src/common.h
@@ -0,0 +1,34 @@
+#ifndef __COMMON_H__
+#define __COMMON_H__
+
+/* 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,
+};
+
+#endif
diff --git a/examples/device/cdc_uac2/src/main.c b/examples/device/cdc_uac2/src/main.c
new file mode 100644
index 000000000..7afa96c1a
--- /dev/null
+++ b/examples/device/cdc_uac2/src/main.c
@@ -0,0 +1,99 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Jerzy Kasenberg
+ * Copyright (c) 2022 Angel Molina <[email protected]>
+ * Copyright (c) 2023 Dhiru Kholia <[email protected]>
+ *
+ * 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 "common.h"
+
+extern uint32_t blink_interval_ms;
+
+#if (CFG_TUSB_MCU == OPT_MCU_RP2040)
+#include "pico/stdlib.h"
+#endif
+
+void led_blinking_task(void);
+
+/*------------- MAIN -------------*/
+int main(void)
+{
+  board_init();
+
+  // init device stack on configured roothub port
+  tud_init(BOARD_TUD_RHPORT);
+
+#if (CFG_TUSB_MCU == OPT_MCU_RP2040)
+  stdio_init_all();
+#endif
+
+  TU_LOG1("CDC UAC2 example running\r\n");
+
+  while (1)
+  {
+    tud_task(); // TinyUSB device task
+    led_blinking_task();
+
+#if (CFG_TUSB_MCU == OPT_MCU_RP2040)
+    // printf("Hello, world!\n");
+#endif
+  }
+
+  return 0;
+}
+
+//--------------------------------------------------------------------+
+// Device callbacks
+//--------------------------------------------------------------------+
+
+// Invoked when device is mounted
+void tud_mount_cb(void)
+{
+  blink_interval_ms = BLINK_MOUNTED;
+}
+
+// Invoked when device is unmounted
+void tud_umount_cb(void)
+{
+  blink_interval_ms = BLINK_NOT_MOUNTED;
+}
+
+// Invoked when usb bus is suspended
+// remote_wakeup_en : if host allow us  to perform remote wakeup
+// Within 7ms, device must draw an average of current less than 2.5 mA from bus
+void tud_suspend_cb(bool remote_wakeup_en)
+{
+  (void)remote_wakeup_en;
+  blink_interval_ms = BLINK_SUSPENDED;
+}
+
+// Invoked when usb bus is resumed
+void tud_resume_cb(void)
+{
+  blink_interval_ms = BLINK_MOUNTED;
+}
diff --git a/examples/device/cdc_uac2/src/tusb_config.h b/examples/device/cdc_uac2/src/tusb_config.h
new file mode 100644
index 000000000..373f0b01f
--- /dev/null
+++ b/examples/device/cdc_uac2/src/tusb_config.h
@@ -0,0 +1,174 @@
+/*
+ * 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
+
+#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
+//--------------------------------------------------------------------
+
+#ifndef CFG_TUD_ENDPOINT0_SIZE
+#define CFG_TUD_ENDPOINT0_SIZE    64
+#endif
+
+//------------- CLASS -------------//
+#define CFG_TUD_CDC               1
+#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
+//--------------------------------------------------------------------
+
+#define CFG_TUD_AUDIO_FUNC_1_DESC_LEN                                TUD_AUDIO_HEADSET_STEREO_DESC_LEN
+
+// How many formats are used, need to adjust USB descriptor if changed
+#define CFG_TUD_AUDIO_FUNC_1_N_FORMATS                               2
+
+// Audio format type I specifications
+#if defined(__RX__)
+#define CFG_TUD_AUDIO_FUNC_1_MAX_SAMPLE_RATE                         48000     // 16bit/48kHz is the best quality for Renesas RX
+#else
+#define CFG_TUD_AUDIO_FUNC_1_MAX_SAMPLE_RATE                         96000     // 24bit/96kHz is the best quality for full-speed, high-speed is needed beyond this
+#endif
+#define CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_TX                           1
+#define CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_RX                           1         // Changed
+
+// 16bit in 16bit slots
+#define CFG_TUD_AUDIO_FUNC_1_FORMAT_1_N_BYTES_PER_SAMPLE_TX          2
+#define CFG_TUD_AUDIO_FUNC_1_FORMAT_1_RESOLUTION_TX                  16
+#define CFG_TUD_AUDIO_FUNC_1_FORMAT_1_N_BYTES_PER_SAMPLE_RX          2
+#define CFG_TUD_AUDIO_FUNC_1_FORMAT_1_RESOLUTION_RX                  16
+
+#if defined(__RX__)
+// 8bit in 8bit slots
+#define CFG_TUD_AUDIO_FUNC_1_FORMAT_2_N_BYTES_PER_SAMPLE_TX          1
+#define CFG_TUD_AUDIO_FUNC_1_FORMAT_2_RESOLUTION_TX                  8
+#define CFG_TUD_AUDIO_FUNC_1_FORMAT_2_N_BYTES_PER_SAMPLE_RX          1
+#define CFG_TUD_AUDIO_FUNC_1_FORMAT_2_RESOLUTION_RX                  8
+#else
+// 24bit in 32bit slots
+#define CFG_TUD_AUDIO_FUNC_1_FORMAT_2_N_BYTES_PER_SAMPLE_TX          4
+#define CFG_TUD_AUDIO_FUNC_1_FORMAT_2_RESOLUTION_TX                  24
+#define CFG_TUD_AUDIO_FUNC_1_FORMAT_2_N_BYTES_PER_SAMPLE_RX          4
+#define CFG_TUD_AUDIO_FUNC_1_FORMAT_2_RESOLUTION_RX                  24
+#endif
+
+// 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_IN                1
+
+#define CFG_TUD_AUDIO_FUNC_1_FORMAT_1_EP_SZ_IN    TUD_AUDIO_EP_SIZE(CFG_TUD_AUDIO_FUNC_1_MAX_SAMPLE_RATE, CFG_TUD_AUDIO_FUNC_1_FORMAT_1_N_BYTES_PER_SAMPLE_TX, CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_TX)
+#define CFG_TUD_AUDIO_FUNC_1_FORMAT_2_EP_SZ_IN    TUD_AUDIO_EP_SIZE(CFG_TUD_AUDIO_FUNC_1_MAX_SAMPLE_RATE, CFG_TUD_AUDIO_FUNC_1_FORMAT_2_N_BYTES_PER_SAMPLE_TX, CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_TX)
+
+#define CFG_TUD_AUDIO_FUNC_1_EP_IN_SW_BUF_SZ      TU_MAX(CFG_TUD_AUDIO_FUNC_1_FORMAT_1_EP_SZ_IN, CFG_TUD_AUDIO_FUNC_1_FORMAT_1_EP_SZ_IN)
+#define CFG_TUD_AUDIO_FUNC_1_EP_IN_SZ_MAX         TU_MAX(CFG_TUD_AUDIO_FUNC_1_FORMAT_1_EP_SZ_IN, CFG_TUD_AUDIO_FUNC_1_FORMAT_1_EP_SZ_IN) // Maximum EP IN size for all AS alternate settings used
+
+// 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_UNC_1_FORMAT_1_EP_SZ_OUT    TUD_AUDIO_EP_SIZE(CFG_TUD_AUDIO_FUNC_1_MAX_SAMPLE_RATE, CFG_TUD_AUDIO_FUNC_1_FORMAT_1_N_BYTES_PER_SAMPLE_RX, CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_RX)
+#define CFG_TUD_AUDIO_UNC_1_FORMAT_2_EP_SZ_OUT    TUD_AUDIO_EP_SIZE(CFG_TUD_AUDIO_FUNC_1_MAX_SAMPLE_RATE, CFG_TUD_AUDIO_FUNC_1_FORMAT_2_N_BYTES_PER_SAMPLE_RX, CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_RX)
+
+#define CFG_TUD_AUDIO_FUNC_1_EP_OUT_SW_BUF_SZ     TU_MAX(CFG_TUD_AUDIO_UNC_1_FORMAT_1_EP_SZ_OUT, CFG_TUD_AUDIO_UNC_1_FORMAT_1_EP_SZ_OUT)
+#define CFG_TUD_AUDIO_FUNC_1_EP_OUT_SZ_MAX        TU_MAX(CFG_TUD_AUDIO_UNC_1_FORMAT_1_EP_SZ_OUT, CFG_TUD_AUDIO_UNC_1_FORMAT_1_EP_SZ_OUT) // Maximum EP IN size for all AS alternate settings used
+
+// 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 	          2
+
+// Size of control request buffer
+#define CFG_TUD_AUDIO_FUNC_1_CTRL_BUF_SZ          64
+
+// CDC FIFO size of TX and RX
+#define CFG_TUD_CDC_RX_BUFSIZE                    64
+#define CFG_TUD_CDC_TX_BUFSIZE                    64
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _TUSB_CONFIG_H_ */
diff --git a/examples/device/cdc_uac2/src/uac2_app.c b/examples/device/cdc_uac2/src/uac2_app.c
new file mode 100644
index 000000000..98659ea68
--- /dev/null
+++ b/examples/device/cdc_uac2/src/uac2_app.c
@@ -0,0 +1,316 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Jerzy Kasenberg
+ * Copyright (c) 2022 Angel Molina ([email protected])
+ *
+ * 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.h"
+
+//--------------------------------------------------------------------+
+// MACRO CONSTANT TYPEDEF PROTOTYPES
+//--------------------------------------------------------------------+
+
+// List of supported sample rates
+const uint32_t sample_rates[] = {44100, 48000};
+uint32_t current_sample_rate  = 44100;
+
+#define N_SAMPLE_RATES  TU_ARRAY_SIZE(sample_rates)
+
+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 microphone data
+int32_t mic_buf[CFG_TUD_AUDIO_FUNC_1_EP_IN_SW_BUF_SZ / 4];
+// Buffer for speaker data
+int32_t spk_buf[CFG_TUD_AUDIO_FUNC_1_EP_OUT_SW_BUF_SZ / 4];
+// Speaker data size received in the last frame
+int spk_data_size;
+// Resolution per format
+const uint8_t resolutions_per_format[CFG_TUD_AUDIO_FUNC_1_N_FORMATS] = {CFG_TUD_AUDIO_FUNC_1_FORMAT_1_RESOLUTION_RX};
+// Current resolution, update on format change
+uint8_t current_resolution;
+
+// 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_SPK_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_SPK_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_SPK_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;
+  }
+}
+
+//--------------------------------------------------------------------+
+// Application Callback API Implementations
+//--------------------------------------------------------------------+
+
+// 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_SPK_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_SPK_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_SPK == itf && alt == 0) {
+    // Audio streaming stop
+    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_SPK == itf && alt != 0) {
+    // Audio streaming start
+    blink_interval_ms = BLINK_STREAMING;
+  }
+
+  // Clear buffer when streaming format is changed
+  spk_data_size = 0;
+  if(alt != 0)
+  {
+    current_resolution = resolutions_per_format[alt-1];
+  }
+
+  return true;
+}
+
+bool tud_audio_rx_done_pre_read_cb(uint8_t rhport, uint16_t n_bytes_received, uint8_t func_id, uint8_t ep_out, uint8_t cur_alt_setting)
+{
+  (void)rhport;
+  (void)func_id;
+  (void)ep_out;
+  (void)cur_alt_setting;
+
+  spk_data_size = tud_audio_read(spk_buf, n_bytes_received);
+  tud_audio_write(spk_buf, n_bytes_received);
+
+  return true;
+}
+
+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;
+
+  // This callback could be used to fill microphone data separately
+  return true;
+}
+
+//--------------------------------------------------------------------+
+// 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;
+}
diff --git a/examples/device/cdc_uac2/src/usb_descriptors.c b/examples/device/cdc_uac2/src/usb_descriptors.c
new file mode 100644
index 000000000..72a695622
--- /dev/null
+++ b/examples/device/cdc_uac2/src/usb_descriptors.c
@@ -0,0 +1,216 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Ha Thach (tinyusb.org)
+ * Copyright (c) 2020 Jerzy Kasenberg
+ * Copyright (c) 2022 Angel Molina ([email protected])
+ *
+ * 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"
+
+/* 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)
+    // 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
+//--------------------------------------------------------------------+
+#define CONFIG_TOTAL_LEN    	(TUD_CONFIG_DESC_LEN + CFG_TUD_AUDIO * TUD_AUDIO_HEADSET_STEREO_DESC_LEN + CFG_TUD_CDC * TUD_CDC_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_IN    0x03
+  #define EPNUM_AUDIO_OUT   0x03
+
+  #define EPNUM_CDC_NOTIF   0x84
+  #define EPNUM_CDC_OUT     0x05
+  #define EPNUM_CDC_IN      0x85
+
+#elif CFG_TUSB_MCU == OPT_MCU_NRF5X
+  // ISO endpoints for NRF5x are fixed to 0x08 (0x88)
+  #define EPNUM_AUDIO_IN    0x08
+  #define EPNUM_AUDIO_OUT   0x08
+
+  #define EPNUM_CDC_NOTIF   0x81
+  #define EPNUM_CDC_OUT     0x02
+  #define EPNUM_CDC_IN      0x82
+
+#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_IN    0x01
+  #define EPNUM_AUDIO_OUT   0x02
+
+  #define EPNUM_CDC_NOTIF   0x83
+  #define EPNUM_CDC_OUT     0x04
+  #define EPNUM_CDC_IN      0x85
+
+#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_IN    0x01
+  #define EPNUM_AUDIO_OUT   0x02
+
+  #define EPNUM_CDC_NOTIF   0x83
+  #define EPNUM_CDC_OUT     0x04
+  #define EPNUM_CDC_IN      0x85
+
+#else
+  #define EPNUM_AUDIO_IN    0x01
+  #define EPNUM_AUDIO_OUT   0x01
+
+  #define EPNUM_CDC_NOTIF   0x83
+  #define EPNUM_CDC_OUT     0x04
+  #define EPNUM_CDC_IN      0x84
+#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, EP Out & EP In address, EP size
+    TUD_AUDIO_HEADSET_STEREO_DESCRIPTOR(2, EPNUM_AUDIO_OUT, EPNUM_AUDIO_IN | 0x80),
+
+    // CDC: Interface number, string index, EP notification address and size, EP data address (out, in) and size.
+    TUD_CDC_DESCRIPTOR(ITF_NUM_CDC, 6, EPNUM_CDC_NOTIF, 8, EPNUM_CDC_OUT, EPNUM_CDC_IN, 64)
+};
+
+// 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 headset",              // 2: Product
+  NULL,                           // 3: Serials will use unique ID if possible
+  "TinyUSB Speakers",             // 4: Audio Interface
+  "TinyUSB Microphone",           // 5: Audio Interface
+  "TinyUSB CDC",                  // 6: 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/cdc_uac2/src/usb_descriptors.h b/examples/device/cdc_uac2/src/usb_descriptors.h
new file mode 100644
index 000000000..736feeefe
--- /dev/null
+++ b/examples/device/cdc_uac2/src/usb_descriptors.h
@@ -0,0 +1,158 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Jerzy Kasenbreg
+ * Copyright (c) 2022 Angel Molina ([email protected])
+ *
+ * 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_
+
+// #include "tusb.h"
+
+// Unit numbers are arbitrary selected
+#define UAC2_ENTITY_CLOCK               0x04
+// Speaker path
+#define UAC2_ENTITY_SPK_INPUT_TERMINAL  0x01
+#define UAC2_ENTITY_SPK_FEATURE_UNIT    0x02
+#define UAC2_ENTITY_SPK_OUTPUT_TERMINAL 0x03
+// Microphone path
+#define UAC2_ENTITY_MIC_INPUT_TERMINAL  0x11
+#define UAC2_ENTITY_MIC_OUTPUT_TERMINAL 0x13
+
+enum
+{
+  ITF_NUM_AUDIO_CONTROL = 0,
+  ITF_NUM_AUDIO_STREAMING_SPK,
+  ITF_NUM_AUDIO_STREAMING_MIC,
+  ITF_NUM_CDC,
+  ITF_NUM_CDC_DATA,
+  ITF_NUM_TOTAL
+};
+
+#define TUD_AUDIO_HEADSET_STEREO_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_FEATURE_UNIT_TWO_CHANNEL_LEN\
+    + TUD_AUDIO_DESC_OUTPUT_TERM_LEN\
+    + TUD_AUDIO_DESC_INPUT_TERM_LEN\
+    + TUD_AUDIO_DESC_OUTPUT_TERM_LEN\
+    /* Interface 1, Alternate 0 */\
+    + TUD_AUDIO_DESC_STD_AS_INT_LEN\
+    /* Interface 1, Alternate 0 */\
+    + 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\
+    /* Interface 1, Alternate 2 */\
+    + 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\
+    /* Interface 2, Alternate 0 */\
+    + TUD_AUDIO_DESC_STD_AS_INT_LEN\
+    /* Interface 2, Alternate 1 */\
+    + 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\
+    /* Interface 2, Alternate 2 */\
+    + 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)
+
+#define TUD_AUDIO_HEADSET_STEREO_DESCRIPTOR(_stridx, _epout, _epin) \
+    /* Standard Interface Association Descriptor (IAD) */\
+    TUD_AUDIO_DESC_IAD(/*_firstitfs*/ ITF_NUM_AUDIO_CONTROL, /*_nitfs*/ 3, /*_stridx*/ 0x00),\
+    /* Standard AC Interface Descriptor(4.7.1) */\
+    TUD_AUDIO_DESC_STD_AC(/*_itfnum*/ ITF_NUM_AUDIO_CONTROL, /*_nEPs*/ 0x00, /*_stridx*/ _stridx),\
+    /* Class-Specific AC Interface Header Descriptor(4.7.2) */\
+    TUD_AUDIO_DESC_CS_AC(/*_bcdADC*/ 0x0200, /*_category*/ AUDIO_FUNC_HEADSET, /*_totallen*/ TUD_AUDIO_DESC_CLK_SRC_LEN+TUD_AUDIO_DESC_FEATURE_UNIT_TWO_CHANNEL_LEN+TUD_AUDIO_DESC_INPUT_TERM_LEN+TUD_AUDIO_DESC_OUTPUT_TERM_LEN+TUD_AUDIO_DESC_INPUT_TERM_LEN+TUD_AUDIO_DESC_OUTPUT_TERM_LEN, /*_ctrl*/ AUDIO_CS_AS_INTERFACE_CTRL_LATENCY_POS),\
+    /* Clock Source Descriptor(4.7.2.1) */\
+    TUD_AUDIO_DESC_CLK_SRC(/*_clkid*/ UAC2_ENTITY_CLOCK, /*_attr*/ 3, /*_ctrl*/ 7, /*_assocTerm*/ 0x00,  /*_stridx*/ 0x00),    \
+    /* Input Terminal Descriptor(4.7.2.4) */\
+    TUD_AUDIO_DESC_INPUT_TERM(/*_termid*/ UAC2_ENTITY_SPK_INPUT_TERMINAL, /*_termtype*/ AUDIO_TERM_TYPE_USB_STREAMING, /*_assocTerm*/ 0x00, /*_clkid*/ UAC2_ENTITY_CLOCK, /*_nchannelslogical*/ 0x02, /*_channelcfg*/ AUDIO_CHANNEL_CONFIG_NON_PREDEFINED, /*_idxchannelnames*/ 0x00, /*_ctrl*/ 0 * (AUDIO_CTRL_R << AUDIO_IN_TERM_CTRL_CONNECTOR_POS), /*_stridx*/ 0x00),\
+    /* Feature Unit Descriptor(4.7.2.8) */\
+    TUD_AUDIO_DESC_FEATURE_UNIT_TWO_CHANNEL(/*_unitid*/ UAC2_ENTITY_SPK_FEATURE_UNIT, /*_srcid*/ UAC2_ENTITY_SPK_INPUT_TERMINAL, /*_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),\
+    /* Output Terminal Descriptor(4.7.2.5) */\
+    TUD_AUDIO_DESC_OUTPUT_TERM(/*_termid*/ UAC2_ENTITY_SPK_OUTPUT_TERMINAL, /*_termtype*/ AUDIO_TERM_TYPE_OUT_HEADPHONES, /*_assocTerm*/ 0x00, /*_srcid*/ UAC2_ENTITY_SPK_FEATURE_UNIT, /*_clkid*/ UAC2_ENTITY_CLOCK, /*_ctrl*/ 0x0000, /*_stridx*/ 0x00),\
+    /* Input Terminal Descriptor(4.7.2.4) */\
+    TUD_AUDIO_DESC_INPUT_TERM(/*_termid*/ UAC2_ENTITY_MIC_INPUT_TERMINAL, /*_termtype*/ AUDIO_TERM_TYPE_IN_GENERIC_MIC, /*_assocTerm*/ 0x00, /*_clkid*/ UAC2_ENTITY_CLOCK, /*_nchannelslogical*/ 0x01, /*_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*/ UAC2_ENTITY_MIC_OUTPUT_TERMINAL, /*_termtype*/ AUDIO_TERM_TYPE_USB_STREAMING, /*_assocTerm*/ 0x00, /*_srcid*/ UAC2_ENTITY_MIC_INPUT_TERMINAL, /*_clkid*/ UAC2_ENTITY_CLOCK, /*_ctrl*/ 0x0000, /*_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)(ITF_NUM_AUDIO_STREAMING_SPK), /*_altset*/ 0x00, /*_nEPs*/ 0x00, /*_stridx*/ 0x05),\
+    /* 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)(ITF_NUM_AUDIO_STREAMING_SPK), /*_altset*/ 0x01, /*_nEPs*/ 0x01, /*_stridx*/ 0x05),\
+    /* Class-Specific AS Interface Descriptor(4.9.2) */\
+    TUD_AUDIO_DESC_CS_AS_INT(/*_termid*/ UAC2_ENTITY_SPK_INPUT_TERMINAL, /*_ctrl*/ AUDIO_CTRL_NONE, /*_formattype*/ AUDIO_FORMAT_TYPE_I, /*_formats*/ AUDIO_DATA_FORMAT_TYPE_I_PCM, /*_nchannelsphysical*/ CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_RX, /*_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(CFG_TUD_AUDIO_FUNC_1_FORMAT_1_N_BYTES_PER_SAMPLE_RX, CFG_TUD_AUDIO_FUNC_1_FORMAT_1_RESOLUTION_RX),\
+    /* Standard AS Isochronous Audio Data Endpoint Descriptor(4.10.1.1) */\
+    TUD_AUDIO_DESC_STD_AS_ISO_EP(/*_ep*/ _epout, /*_attr*/ (uint8_t) (TUSB_XFER_ISOCHRONOUS | TUSB_ISO_EP_ATT_ADAPTIVE | TUSB_ISO_EP_ATT_DATA), /*_maxEPsize*/ TUD_AUDIO_EP_SIZE(CFG_TUD_AUDIO_FUNC_1_MAX_SAMPLE_RATE, CFG_TUD_AUDIO_FUNC_1_FORMAT_1_N_BYTES_PER_SAMPLE_RX, CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_RX), /*_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),\
+    /* Interface 1, Alternate 2 - alternate interface for data streaming */\
+    TUD_AUDIO_DESC_STD_AS_INT(/*_itfnum*/ (uint8_t)(ITF_NUM_AUDIO_STREAMING_SPK), /*_altset*/ 0x02, /*_nEPs*/ 0x01, /*_stridx*/ 0x05),\
+    /* Class-Specific AS Interface Descriptor(4.9.2) */\
+    TUD_AUDIO_DESC_CS_AS_INT(/*_termid*/ UAC2_ENTITY_SPK_INPUT_TERMINAL, /*_ctrl*/ AUDIO_CTRL_NONE, /*_formattype*/ AUDIO_FORMAT_TYPE_I, /*_formats*/ AUDIO_DATA_FORMAT_TYPE_I_PCM, /*_nchannelsphysical*/ CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_RX, /*_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(CFG_TUD_AUDIO_FUNC_1_FORMAT_2_N_BYTES_PER_SAMPLE_RX, CFG_TUD_AUDIO_FUNC_1_FORMAT_2_RESOLUTION_RX),\
+    /* Standard AS Isochronous Audio Data Endpoint Descriptor(4.10.1.1) */\
+    TUD_AUDIO_DESC_STD_AS_ISO_EP(/*_ep*/ _epout, /*_attr*/ (uint8_t) (TUSB_XFER_ISOCHRONOUS | TUSB_ISO_EP_ATT_ADAPTIVE | TUSB_ISO_EP_ATT_DATA), /*_maxEPsize*/ TUD_AUDIO_EP_SIZE(CFG_TUD_AUDIO_FUNC_1_MAX_SAMPLE_RATE, CFG_TUD_AUDIO_FUNC_1_FORMAT_2_N_BYTES_PER_SAMPLE_RX, CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_RX), /*_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 Interface Descriptor(4.9.1) */\
+    /* Interface 2, Alternate 0 - default alternate setting with 0 bandwidth */\
+    TUD_AUDIO_DESC_STD_AS_INT(/*_itfnum*/ (uint8_t)(ITF_NUM_AUDIO_STREAMING_MIC), /*_altset*/ 0x00, /*_nEPs*/ 0x00, /*_stridx*/ 0x04),\
+    /* Standard AS Interface Descriptor(4.9.1) */\
+    /* Interface 2, Alternate 1 - alternate interface for data streaming */\
+    TUD_AUDIO_DESC_STD_AS_INT(/*_itfnum*/ (uint8_t)(ITF_NUM_AUDIO_STREAMING_MIC), /*_altset*/ 0x01, /*_nEPs*/ 0x01, /*_stridx*/ 0x04),\
+    /* Class-Specific AS Interface Descriptor(4.9.2) */\
+    TUD_AUDIO_DESC_CS_AS_INT(/*_termid*/ UAC2_ENTITY_MIC_OUTPUT_TERMINAL, /*_ctrl*/ AUDIO_CTRL_NONE, /*_formattype*/ AUDIO_FORMAT_TYPE_I, /*_formats*/ AUDIO_DATA_FORMAT_TYPE_I_PCM, /*_nchannelsphysical*/ CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_TX, /*_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(CFG_TUD_AUDIO_FUNC_1_FORMAT_1_N_BYTES_PER_SAMPLE_TX, CFG_TUD_AUDIO_FUNC_1_FORMAT_1_RESOLUTION_TX),\
+    /* Standard AS Isochronous Audio Data Endpoint Descriptor(4.10.1.1) */\
+    TUD_AUDIO_DESC_STD_AS_ISO_EP(/*_ep*/ _epin, /*_attr*/ (uint8_t) (TUSB_XFER_ISOCHRONOUS | TUSB_ISO_EP_ATT_ASYNCHRONOUS | TUSB_ISO_EP_ATT_DATA), /*_maxEPsize*/ TUD_AUDIO_EP_SIZE(CFG_TUD_AUDIO_FUNC_1_MAX_SAMPLE_RATE, CFG_TUD_AUDIO_FUNC_1_FORMAT_1_N_BYTES_PER_SAMPLE_TX, CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_TX), /*_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_UNDEFINED, /*_lockdelay*/ 0x0000),\
+    /* Interface 2, Alternate 2 - alternate interface for data streaming */\
+    TUD_AUDIO_DESC_STD_AS_INT(/*_itfnum*/ (uint8_t)(ITF_NUM_AUDIO_STREAMING_MIC), /*_altset*/ 0x02, /*_nEPs*/ 0x01, /*_stridx*/ 0x04),\
+    /* Class-Specific AS Interface Descriptor(4.9.2) */\
+    TUD_AUDIO_DESC_CS_AS_INT(/*_termid*/ UAC2_ENTITY_MIC_OUTPUT_TERMINAL, /*_ctrl*/ AUDIO_CTRL_NONE, /*_formattype*/ AUDIO_FORMAT_TYPE_I, /*_formats*/ AUDIO_DATA_FORMAT_TYPE_I_PCM, /*_nchannelsphysical*/ CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_TX, /*_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(CFG_TUD_AUDIO_FUNC_1_FORMAT_2_N_BYTES_PER_SAMPLE_TX, CFG_TUD_AUDIO_FUNC_1_FORMAT_2_RESOLUTION_TX),\
+    /* Standard AS Isochronous Audio Data Endpoint Descriptor(4.10.1.1) */\
+    TUD_AUDIO_DESC_STD_AS_ISO_EP(/*_ep*/ _epin, /*_attr*/ (uint8_t) (TUSB_XFER_ISOCHRONOUS | TUSB_ISO_EP_ATT_ASYNCHRONOUS | TUSB_ISO_EP_ATT_DATA), /*_maxEPsize*/ TUD_AUDIO_EP_SIZE(CFG_TUD_AUDIO_FUNC_1_MAX_SAMPLE_RATE, CFG_TUD_AUDIO_FUNC_1_FORMAT_2_N_BYTES_PER_SAMPLE_TX, CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_TX), /*_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_UNDEFINED, /*_lockdelay*/ 0x0000)
+
+#endif
diff --git a/examples/device/dfu/src/main.c b/examples/device/dfu/src/main.c
index 5f37f25e1..81fc0a62c 100644
--- a/examples/device/dfu/src/main.c
+++ b/examples/device/dfu/src/main.c
@@ -42,7 +42,7 @@
 #include <stdio.h>
 #include <string.h>
 
-#include "bsp/board.h"
+#include "bsp/board_api.h"
 #include "tusb.h"
 
 //--------------------------------------------------------------------+
@@ -77,6 +77,10 @@ int main(void)
   // init device stack on configured roothub port
   tud_init(BOARD_TUD_RHPORT);
 
+  if (board_init_after_tusb) {
+    board_init_after_tusb();
+  }
+
   while (1)
   {
     tud_task(); // tinyusb device task
@@ -112,7 +116,7 @@ void tud_suspend_cb(bool remote_wakeup_en)
 // Invoked when usb bus is resumed
 void tud_resume_cb(void)
 {
-  blink_interval_ms = BLINK_MOUNTED;
+  blink_interval_ms = tud_mounted() ? BLINK_MOUNTED : BLINK_NOT_MOUNTED;
 }
 
 //--------------------------------------------------------------------+
diff --git a/examples/device/dfu/src/usb_descriptors.c b/examples/device/dfu/src/usb_descriptors.c
index 51a0d09f5..fd469aaf2 100644
--- a/examples/device/dfu/src/usb_descriptors.c
+++ b/examples/device/dfu/src/usb_descriptors.c
@@ -23,6 +23,7 @@
  *
  */
 
+#include "bsp/board_api.h"
 #include "tusb.h"
 #include "class/dfu/dfu_device.h"
 
@@ -116,56 +117,65 @@ uint8_t const * tud_descriptor_configuration_cb(uint8_t index)
 // 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 [] =
+char const *string_desc_arr[] =
 {
   (const char[]) { 0x09, 0x04 }, // 0: is supported language is English (0x0409)
   "TinyUSB",                     // 1: Manufacturer
   "TinyUSB Device",              // 2: Product
-  "123456",                      // 3: Serials, should use chip ID
+  NULL,                          // 3: Serials will use unique ID if possible
   "FLASH",                       // 4: DFU Partition 1
   "EEPROM",                      // 5: DFU Partition 2
 };
 
-static uint16_t _desc_str[32];
+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)
-{
+uint16_t const *tud_descriptor_string_cb(uint8_t index, uint16_t langid) {
   (void) langid;
-
   size_t chr_count;
 
-  if ( index == 0)
-  {
-    memcpy(&_desc_str[1], string_desc_arr[0], 2);
-    chr_count = 1;
-  }
-  else
-  {
-    // 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
+  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;
+      if ( !(index < sizeof(string_desc_arr) / sizeof(string_desc_arr[0])) ) return NULL;
 
-    const char* str = string_desc_arr[index];
+      const char *str = string_desc_arr[index];
 
-    // Cap at max char
-    chr_count = (uint8_t) strlen(str);
-    if ( chr_count > 31 ) {
-      chr_count = 31;
-    }
+      // 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(uint8_t i=0; i<chr_count; i++)
-    {
-      _desc_str[1+i] = str[i];
-    }
+      // 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)((((uint16_t)TUSB_DESC_STRING) << 8 ) | (2u*chr_count + 2u));
+  _desc_str[0] = (uint16_t) ((TUSB_DESC_STRING << 8) | (2 * chr_count + 2));
 
   return _desc_str;
 }
diff --git a/examples/device/dfu_runtime/src/main.c b/examples/device/dfu_runtime/src/main.c
index 4ec3cb188..170dde932 100644
--- a/examples/device/dfu_runtime/src/main.c
+++ b/examples/device/dfu_runtime/src/main.c
@@ -40,7 +40,7 @@
 #include <stdio.h>
 #include <string.h>
 
-#include "bsp/board.h"
+#include "bsp/board_api.h"
 #include "tusb.h"
 
 //--------------------------------------------------------------------+
@@ -72,6 +72,10 @@ int main(void)
   // init device stack on configured roothub port
   tud_init(BOARD_TUD_RHPORT);
 
+  if (board_init_after_tusb) {
+    board_init_after_tusb();
+  }
+
   while (1)
   {
     tud_task(); // tinyusb device task
@@ -107,7 +111,7 @@ void tud_suspend_cb(bool remote_wakeup_en)
 // Invoked when usb bus is resumed
 void tud_resume_cb(void)
 {
-  blink_interval_ms = BLINK_MOUNTED;
+  blink_interval_ms = tud_mounted() ? BLINK_MOUNTED : BLINK_NOT_MOUNTED;
 }
 
 // Invoked on DFU_DETACH request to reboot to the bootloader
diff --git a/examples/device/dfu_runtime/src/usb_descriptors.c b/examples/device/dfu_runtime/src/usb_descriptors.c
index 1b0a60551..7ac53d255 100644
--- a/examples/device/dfu_runtime/src/usb_descriptors.c
+++ b/examples/device/dfu_runtime/src/usb_descriptors.c
@@ -23,6 +23,7 @@
  *
  */
 
+#include "bsp/board_api.h"
 #include "tusb.h"
 #include "class/dfu/dfu_rt_device.h"
 
@@ -112,55 +113,64 @@ uint8_t const * tud_descriptor_configuration_cb(uint8_t index)
 // 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 [] =
+char const *string_desc_arr[] =
 {
   (const char[]) { 0x09, 0x04 }, // 0: is supported language is English (0x0409)
   "TinyUSB",                     // 1: Manufacturer
   "TinyUSB Device",              // 2: Product
-  "123456",                      // 3: Serials, should use chip ID
+  NULL,                          // 3: Serials will use unique ID if possible
   "TinyUSB DFU runtime",         // 4: DFU runtime
 };
 
-static uint16_t _desc_str[32];
+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)
-{
+uint16_t const *tud_descriptor_string_cb(uint8_t index, uint16_t langid) {
   (void) langid;
-
   size_t chr_count;
 
-  if ( index == 0)
-  {
-    memcpy(&_desc_str[1], string_desc_arr[0], 2);
-    chr_count = 1;
-  }
-  else
-  {
-    // 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
+  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;
+      if ( !(index < sizeof(string_desc_arr) / sizeof(string_desc_arr[0])) ) return NULL;
 
-    const char* str = string_desc_arr[index];
+      const char *str = string_desc_arr[index];
 
-    // Cap at max char
-    chr_count = (uint8_t) strlen(str);
-    if ( chr_count > 31 ) {
-      chr_count = 31;
-    }
+      // 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(uint8_t i=0; i<chr_count; i++)
-    {
-      _desc_str[1+i] = str[i];
-    }
+      // 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));
+  _desc_str[0] = (uint16_t) ((TUSB_DESC_STRING << 8) | (2 * chr_count + 2));
 
   return _desc_str;
 }
diff --git a/examples/device/dynamic_configuration/src/main.c b/examples/device/dynamic_configuration/src/main.c
index 578f01d8c..b6409c8e1 100644
--- a/examples/device/dynamic_configuration/src/main.c
+++ b/examples/device/dynamic_configuration/src/main.c
@@ -27,7 +27,7 @@
 #include <stdio.h>
 #include <string.h>
 
-#include "bsp/board.h"
+#include "bsp/board_api.h"
 #include "tusb.h"
 
 //--------------------------------------------------------------------+
@@ -59,6 +59,10 @@ int main(void)
   // init device stack on configured roothub port
   tud_init(BOARD_TUD_RHPORT);
 
+  if (board_init_after_tusb) {
+    board_init_after_tusb();
+  }
+
   while (1)
   {
     tud_task(); // tinyusb device task
@@ -96,7 +100,7 @@ void tud_suspend_cb(bool remote_wakeup_en)
 // Invoked when usb bus is resumed
 void tud_resume_cb(void)
 {
-  blink_interval_ms = BLINK_MOUNTED;
+  blink_interval_ms = tud_mounted() ? BLINK_MOUNTED : BLINK_NOT_MOUNTED;
 }
 
 
diff --git a/examples/device/dynamic_configuration/src/msc_disk.c b/examples/device/dynamic_configuration/src/msc_disk.c
index 27856a1a4..10c3ac6fe 100644
--- a/examples/device/dynamic_configuration/src/msc_disk.c
+++ b/examples/device/dynamic_configuration/src/msc_disk.c
@@ -23,7 +23,7 @@
  *
  */
 
-#include "bsp/board.h"
+#include "bsp/board_api.h"
 #include "tusb.h"
 
 #if CFG_TUD_MSC
diff --git a/examples/device/dynamic_configuration/src/usb_descriptors.c b/examples/device/dynamic_configuration/src/usb_descriptors.c
index 71348abef..7f35b4b22 100644
--- a/examples/device/dynamic_configuration/src/usb_descriptors.c
+++ b/examples/device/dynamic_configuration/src/usb_descriptors.c
@@ -23,8 +23,8 @@
  *
  */
 
+#include "bsp/board_api.h"
 #include "tusb.h"
-#include "bsp/board.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.
@@ -206,51 +206,63 @@ uint8_t const * tud_descriptor_configuration_cb(uint8_t index)
 // 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 [] =
+char const *string_desc_arr[] =
 {
   (const char[]) { 0x09, 0x04 }, // 0: is supported language is English (0x0409)
   "TinyUSB",                     // 1: Manufacturer
   "TinyUSB Device",              // 2: Product
-  "123456",                      // 3: Serials, should use chip ID
+  NULL,                          // 3: Serials will use unique ID if possible
 };
 
-static uint16_t _desc_str[32];
+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)
-{
+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;
 
-  uint8_t chr_count;
+    case STRID_SERIAL:
+      chr_count = board_usb_get_serial(_desc_str + 1, 32);
+      break;
 
-  if ( index == 0)
-  {
-    memcpy(&_desc_str[1], string_desc_arr[0], 2);
-    chr_count = 1;
-  }else
-  {
-    // 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
+    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;
+      if ( !(index < sizeof(string_desc_arr) / sizeof(string_desc_arr[0])) ) return NULL;
 
-    const char* str = string_desc_arr[index];
+      const char *str = string_desc_arr[index];
 
-    // Cap at max char
-    chr_count = (uint8_t) strlen(str);
-    if ( chr_count > 31 ) chr_count = 31;
+      // 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(uint8_t i=0; i<chr_count; i++)
-    {
-      _desc_str[1+i] = str[i];
-    }
+      // 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));
+  _desc_str[0] = (uint16_t) ((TUSB_DESC_STRING << 8) | (2 * chr_count + 2));
 
   return _desc_str;
 }
diff --git a/examples/device/hid_boot_interface/src/main.c b/examples/device/hid_boot_interface/src/main.c
index 1a155996a..7ad5c53c2 100644
--- a/examples/device/hid_boot_interface/src/main.c
+++ b/examples/device/hid_boot_interface/src/main.c
@@ -27,7 +27,7 @@
 #include <stdio.h>
 #include <string.h>
 
-#include "bsp/board.h"
+#include "bsp/board_api.h"
 #include "tusb.h"
 #include "usb_descriptors.h"
 
@@ -59,6 +59,10 @@ int main(void)
   // init device stack on configured roothub port
   tud_init(BOARD_TUD_RHPORT);
 
+  if (board_init_after_tusb) {
+    board_init_after_tusb();
+  }
+
   while (1)
   {
     tud_task(); // tinyusb device task
@@ -98,7 +102,7 @@ void tud_suspend_cb(bool remote_wakeup_en)
 // Invoked when usb bus is resumed
 void tud_resume_cb(void)
 {
-  blink_interval_ms = BLINK_MOUNTED;
+  blink_interval_ms = tud_mounted() ? BLINK_MOUNTED : BLINK_NOT_MOUNTED;
 }
 
 //--------------------------------------------------------------------+
diff --git a/examples/device/hid_boot_interface/src/usb_descriptors.c b/examples/device/hid_boot_interface/src/usb_descriptors.c
index 10345ab41..d68ef16d9 100644
--- a/examples/device/hid_boot_interface/src/usb_descriptors.c
+++ b/examples/device/hid_boot_interface/src/usb_descriptors.c
@@ -23,6 +23,7 @@
  *
  */
 
+#include "bsp/board_api.h"
 #include "tusb.h"
 #include "usb_descriptors.h"
 
@@ -130,51 +131,63 @@ uint8_t const * tud_descriptor_configuration_cb(uint8_t index)
 // 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 [] =
+char const *string_desc_arr[] =
 {
   (const char[]) { 0x09, 0x04 }, // 0: is supported language is English (0x0409)
   "TinyUSB",                     // 1: Manufacturer
   "TinyUSB Device",              // 2: Product
-  "123456",                      // 3: Serials, should use chip ID
+  NULL,                          // 3: Serials will use unique ID if possible
 };
 
-static uint16_t _desc_str[32];
+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)
-{
+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;
 
-  uint8_t chr_count;
+    case STRID_SERIAL:
+      chr_count = board_usb_get_serial(_desc_str + 1, 32);
+      break;
 
-  if ( index == 0)
-  {
-    memcpy(&_desc_str[1], string_desc_arr[0], 2);
-    chr_count = 1;
-  }else
-  {
-    // 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
+    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;
+      if ( !(index < sizeof(string_desc_arr) / sizeof(string_desc_arr[0])) ) return NULL;
 
-    const char* str = string_desc_arr[index];
+      const char *str = string_desc_arr[index];
 
-    // Cap at max char
-    chr_count = (uint8_t) strlen(str);
-    if ( chr_count > 31 ) chr_count = 31;
+      // 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(uint8_t i=0; i<chr_count; i++)
-    {
-      _desc_str[1+i] = str[i];
-    }
+      // 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));
+  _desc_str[0] = (uint16_t) ((TUSB_DESC_STRING << 8) | (2 * chr_count + 2));
 
   return _desc_str;
 }
diff --git a/examples/device/hid_composite/src/main.c b/examples/device/hid_composite/src/main.c
index 8d0e6bece..dcf13079f 100644
--- a/examples/device/hid_composite/src/main.c
+++ b/examples/device/hid_composite/src/main.c
@@ -27,7 +27,7 @@
 #include <stdio.h>
 #include <string.h>
 
-#include "bsp/board.h"
+#include "bsp/board_api.h"
 #include "tusb.h"
 
 #include "usb_descriptors.h"
@@ -60,6 +60,10 @@ int main(void)
   // init device stack on configured roothub port
   tud_init(BOARD_TUD_RHPORT);
 
+  if (board_init_after_tusb) {
+    board_init_after_tusb();
+  }
+
   while (1)
   {
     tud_task(); // tinyusb device task
@@ -97,7 +101,7 @@ void tud_suspend_cb(bool remote_wakeup_en)
 // Invoked when usb bus is resumed
 void tud_resume_cb(void)
 {
-  blink_interval_ms = BLINK_MOUNTED;
+  blink_interval_ms = tud_mounted() ? BLINK_MOUNTED : BLINK_NOT_MOUNTED;
 }
 
 //--------------------------------------------------------------------+
diff --git a/examples/device/hid_composite/src/usb_descriptors.c b/examples/device/hid_composite/src/usb_descriptors.c
index 347bbf29a..e174db46d 100644
--- a/examples/device/hid_composite/src/usb_descriptors.c
+++ b/examples/device/hid_composite/src/usb_descriptors.c
@@ -23,6 +23,7 @@
  *
  */
 
+#include "bsp/board_api.h"
 #include "tusb.h"
 #include "usb_descriptors.h"
 
@@ -177,51 +178,63 @@ uint8_t const * tud_descriptor_configuration_cb(uint8_t index)
 // 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 [] =
+char const *string_desc_arr[] =
 {
   (const char[]) { 0x09, 0x04 }, // 0: is supported language is English (0x0409)
   "TinyUSB",                     // 1: Manufacturer
   "TinyUSB Device",              // 2: Product
-  "123456",                      // 3: Serials, should use chip ID
+  NULL,                          // 3: Serials will use unique ID if possible
 };
 
-static uint16_t _desc_str[32];
+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)
-{
+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;
 
-  uint8_t chr_count;
+    case STRID_SERIAL:
+      chr_count = board_usb_get_serial(_desc_str + 1, 32);
+      break;
 
-  if ( index == 0)
-  {
-    memcpy(&_desc_str[1], string_desc_arr[0], 2);
-    chr_count = 1;
-  }else
-  {
-    // 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
+    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;
+      if ( !(index < sizeof(string_desc_arr) / sizeof(string_desc_arr[0])) ) return NULL;
 
-    const char* str = string_desc_arr[index];
+      const char *str = string_desc_arr[index];
 
-    // Cap at max char
-    chr_count = (uint8_t) strlen(str);
-    if ( chr_count > 31 ) chr_count = 31;
+      // 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(uint8_t i=0; i<chr_count; i++)
-    {
-      _desc_str[1+i] = str[i];
-    }
+      // 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));
+  _desc_str[0] = (uint16_t) ((TUSB_DESC_STRING << 8) | (2 * chr_count + 2));
 
   return _desc_str;
 }
diff --git a/examples/device/hid_composite_freertos/skip.txt b/examples/device/hid_composite_freertos/skip.txt
index 49b8ee57b..a6f96b288 100644
--- a/examples/device/hid_composite_freertos/skip.txt
+++ b/examples/device/hid_composite_freertos/skip.txt
@@ -8,5 +8,6 @@ mcu:RP2040
 mcu:SAMD11
 mcu:SAMX7X
 mcu:VALENTYUSB_EPTRI
+mcu:RAXXX
 family:broadcom_32bit
 family:broadcom_64bit
diff --git a/examples/device/hid_composite_freertos/src/FreeRTOSConfig/FreeRTOSConfig.h b/examples/device/hid_composite_freertos/src/FreeRTOSConfig/FreeRTOSConfig.h
index 9bef9bbbf..69d638288 100644
--- a/examples/device/hid_composite_freertos/src/FreeRTOSConfig/FreeRTOSConfig.h
+++ b/examples/device/hid_composite_freertos/src/FreeRTOSConfig/FreeRTOSConfig.h
@@ -81,7 +81,7 @@
 #define configUSE_MUTEXES                       1
 #define configUSE_RECURSIVE_MUTEXES             1
 #define configUSE_COUNTING_SEMAPHORES           1
-#define configQUEUE_REGISTRY_SIZE               2
+#define configQUEUE_REGISTRY_SIZE               4
 #define configUSE_QUEUE_SETS                    0
 #define configUSE_TIME_SLICING                  0
 #define configUSE_NEWLIB_REENTRANT              0
diff --git a/examples/device/hid_composite_freertos/src/main.c b/examples/device/hid_composite_freertos/src/main.c
index ca02af100..ff2cb635e 100644
--- a/examples/device/hid_composite_freertos/src/main.c
+++ b/examples/device/hid_composite_freertos/src/main.c
@@ -27,7 +27,7 @@
 #include <stdio.h>
 #include <string.h>
 
-#include "bsp/board.h"
+#include "bsp/board_api.h"
 #include "tusb.h"
 #include "usb_descriptors.h"
 
@@ -138,6 +138,10 @@ void usb_device_task(void* param)
   // Otherwise it could cause kernel issue since USB IRQ handler does use RTOS queue API.
   tud_init(BOARD_TUD_RHPORT);
 
+  if (board_init_after_tusb) {
+    board_init_after_tusb();
+  }
+
   // RTOS forever loop
   while (1)
   {
@@ -176,7 +180,14 @@ void tud_suspend_cb(bool remote_wakeup_en)
 // Invoked when usb bus is resumed
 void tud_resume_cb(void)
 {
-  xTimerChangePeriod(blinky_tm, pdMS_TO_TICKS(BLINK_MOUNTED), 0);
+  if (tud_mounted())
+  {
+    xTimerChangePeriod(blinky_tm, pdMS_TO_TICKS(BLINK_MOUNTED), 0);
+  }
+  else
+  {
+    xTimerChangePeriod(blinky_tm, pdMS_TO_TICKS(BLINK_NOT_MOUNTED), 0);
+  }
 }
 
 //--------------------------------------------------------------------+
diff --git a/examples/device/hid_composite_freertos/src/usb_descriptors.c b/examples/device/hid_composite_freertos/src/usb_descriptors.c
index 30f327d5e..85820de55 100644
--- a/examples/device/hid_composite_freertos/src/usb_descriptors.c
+++ b/examples/device/hid_composite_freertos/src/usb_descriptors.c
@@ -23,6 +23,7 @@
  *
  */
 
+#include "bsp/board_api.h"
 #include "tusb.h"
 #include "usb_descriptors.h"
 
@@ -175,51 +176,63 @@ uint8_t const * tud_descriptor_configuration_cb(uint8_t index)
 // 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 [] =
+char const *string_desc_arr[] =
 {
   (const char[]) { 0x09, 0x04 }, // 0: is supported language is English (0x0409)
   "TinyUSB",                     // 1: Manufacturer
   "TinyUSB Device",              // 2: Product
-  "123456",                      // 3: Serials, should use chip ID
+  NULL,                          // 3: Serials will use unique ID if possible
 };
 
-static uint16_t _desc_str[32];
+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)
-{
+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;
 
-  uint8_t chr_count;
+    case STRID_SERIAL:
+      chr_count = board_usb_get_serial(_desc_str + 1, 32);
+      break;
 
-  if ( index == 0)
-  {
-    memcpy(&_desc_str[1], string_desc_arr[0], 2);
-    chr_count = 1;
-  }else
-  {
-    // 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
+    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;
+      if ( !(index < sizeof(string_desc_arr) / sizeof(string_desc_arr[0])) ) return NULL;
 
-    const char* str = string_desc_arr[index];
+      const char *str = string_desc_arr[index];
 
-    // Cap at max char
-    chr_count = (uint8_t) strlen(str);
-    if ( chr_count > 31 ) chr_count = 31;
+      // 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(uint8_t i=0; i<chr_count; i++)
-    {
-      _desc_str[1+i] = str[i];
-    }
+      // 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));
+  _desc_str[0] = (uint16_t) ((TUSB_DESC_STRING << 8) | (2 * chr_count + 2));
 
   return _desc_str;
 }
diff --git a/examples/device/hid_generic_inout/src/main.c b/examples/device/hid_generic_inout/src/main.c
index 5db8f5581..cfa9f6283 100644
--- a/examples/device/hid_generic_inout/src/main.c
+++ b/examples/device/hid_generic_inout/src/main.c
@@ -27,7 +27,7 @@
 #include <stdio.h>
 #include <string.h>
 
-#include "bsp/board.h"
+#include "bsp/board_api.h"
 #include "tusb.h"
 
 /* This example demonstrate HID Generic raw Input & Output.
@@ -83,6 +83,10 @@ int main(void)
   // init device stack on configured roothub port
   tud_init(BOARD_TUD_RHPORT);
 
+  if (board_init_after_tusb) {
+    board_init_after_tusb();
+  }
+
   while (1)
   {
     tud_task(); // tinyusb device task
@@ -118,7 +122,7 @@ void tud_suspend_cb(bool remote_wakeup_en)
 // Invoked when usb bus is resumed
 void tud_resume_cb(void)
 {
-  blink_interval_ms = BLINK_MOUNTED;
+  blink_interval_ms = tud_mounted() ? BLINK_MOUNTED : BLINK_NOT_MOUNTED;
 }
 
 //--------------------------------------------------------------------+
diff --git a/examples/device/hid_generic_inout/src/usb_descriptors.c b/examples/device/hid_generic_inout/src/usb_descriptors.c
index 8377a0f47..64f6d17ae 100644
--- a/examples/device/hid_generic_inout/src/usb_descriptors.c
+++ b/examples/device/hid_generic_inout/src/usb_descriptors.c
@@ -23,6 +23,7 @@
  *
  */
 
+#include "bsp/board_api.h"
 #include "tusb.h"
 
 /* A combination of interfaces must have a unique product id, since PC will save device driver after the first plug.
@@ -120,51 +121,63 @@ uint8_t const * tud_descriptor_configuration_cb(uint8_t index)
 // 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 [] =
+char const *string_desc_arr[] =
 {
   (const char[]) { 0x09, 0x04 }, // 0: is supported language is English (0x0409)
   "TinyUSB",                     // 1: Manufacturer
   "TinyUSB Device",              // 2: Product
-  "123456",                      // 3: Serials, should use chip ID
+  NULL,                          // 3: Serials will use unique ID if possible
 };
 
-static uint16_t _desc_str[32];
+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)
-{
+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;
 
-  uint8_t chr_count;
+    case STRID_SERIAL:
+      chr_count = board_usb_get_serial(_desc_str + 1, 32);
+      break;
 
-  if ( index == 0)
-  {
-    memcpy(&_desc_str[1], string_desc_arr[0], 2);
-    chr_count = 1;
-  }else
-  {
-    // 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
+    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;
+      if ( !(index < sizeof(string_desc_arr) / sizeof(string_desc_arr[0])) ) return NULL;
 
-    const char* str = string_desc_arr[index];
+      const char *str = string_desc_arr[index];
 
-    // Cap at max char
-    chr_count = (uint8_t) strlen(str);
-    if ( chr_count > 31 ) chr_count = 31;
+      // 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(uint8_t i=0; i<chr_count; i++)
-    {
-      _desc_str[1+i] = str[i];
-    }
+      // 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));
+  _desc_str[0] = (uint16_t) ((TUSB_DESC_STRING << 8) | (2 * chr_count + 2));
 
   return _desc_str;
 }
diff --git a/examples/device/hid_multiple_interface/src/main.c b/examples/device/hid_multiple_interface/src/main.c
index 72240b208..30b4ae055 100644
--- a/examples/device/hid_multiple_interface/src/main.c
+++ b/examples/device/hid_multiple_interface/src/main.c
@@ -27,7 +27,7 @@
 #include <stdio.h>
 #include <string.h>
 
-#include "bsp/board.h"
+#include "bsp/board_api.h"
 #include "tusb.h"
 
 //--------------------------------------------------------------------+
@@ -64,6 +64,10 @@ int main(void)
   // init device stack on configured roothub port
   tud_init(BOARD_TUD_RHPORT);
 
+  if (board_init_after_tusb) {
+    board_init_after_tusb();
+  }
+
   while (1)
   {
     tud_task(); // tinyusb device task
@@ -101,7 +105,7 @@ void tud_suspend_cb(bool remote_wakeup_en)
 // Invoked when usb bus is resumed
 void tud_resume_cb(void)
 {
-  blink_interval_ms = BLINK_MOUNTED;
+  blink_interval_ms = tud_mounted() ? BLINK_MOUNTED : BLINK_NOT_MOUNTED;
 }
 
 //--------------------------------------------------------------------+
diff --git a/examples/device/hid_multiple_interface/src/usb_descriptors.c b/examples/device/hid_multiple_interface/src/usb_descriptors.c
index 42471a961..86f567e8e 100644
--- a/examples/device/hid_multiple_interface/src/usb_descriptors.c
+++ b/examples/device/hid_multiple_interface/src/usb_descriptors.c
@@ -23,6 +23,7 @@
  *
  */
 
+#include "bsp/board_api.h"
 #include "tusb.h"
 
 /* A combination of interfaces must have a unique product id, since PC will save device driver after the first plug.
@@ -136,53 +137,65 @@ uint8_t const * tud_descriptor_configuration_cb(uint8_t index)
 // 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 [] =
+char const *string_desc_arr[] =
 {
   (const char[]) { 0x09, 0x04 },  // 0: is supported language is English (0x0409)
   "TinyUSB",                      // 1: Manufacturer
   "TinyUSB Device",               // 2: Product
-  "123456",                       // 3: Serials, should use chip ID
+  NULL,                           // 3: Serials will use unique ID if possible
   "Keyboard Interface",           // 4: Interface 1 String
   "Mouse Interface",              // 5: Interface 2 String
 };
 
-static uint16_t _desc_str[32];
+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)
-{
+uint16_t const *tud_descriptor_string_cb(uint8_t index, uint16_t langid) {
   (void) langid;
+  size_t chr_count;
 
-  uint8_t chr_count;
+  switch ( index ) {
+    case STRID_LANGID:
+      memcpy(&_desc_str[1], string_desc_arr[0], 2);
+      chr_count = 1;
+      break;
 
-  if ( index == 0)
-  {
-    memcpy(&_desc_str[1], string_desc_arr[0], 2);
-    chr_count = 1;
-  }else
-  {
-    // 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
+    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;
+      if ( !(index < sizeof(string_desc_arr) / sizeof(string_desc_arr[0])) ) return NULL;
 
-    const char* str = string_desc_arr[index];
+      const char *str = string_desc_arr[index];
 
-    // Cap at max char
-    chr_count = (uint8_t) strlen(str);
-    if ( chr_count > 31 ) chr_count = 31;
+      // 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(uint8_t i=0; i<chr_count; i++)
-    {
-      _desc_str[1+i] = str[i];
-    }
+      // 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));
+  _desc_str[0] = (uint16_t) ((TUSB_DESC_STRING << 8) | (2 * chr_count + 2));
 
   return _desc_str;
 }
diff --git a/examples/device/midi_test/src/main.c b/examples/device/midi_test/src/main.c
index 2c3e9d954..b1d51598f 100644
--- a/examples/device/midi_test/src/main.c
+++ b/examples/device/midi_test/src/main.c
@@ -27,7 +27,7 @@
 #include <stdio.h>
 #include <string.h>
 
-#include "bsp/board.h"
+#include "bsp/board_api.h"
 #include "tusb.h"
 
 /* This MIDI example send sequence of note (on/off) repeatedly. To test on PC, you need to install
@@ -65,6 +65,10 @@ int main(void)
   // init device stack on configured roothub port
   tud_init(BOARD_TUD_RHPORT);
 
+  if (board_init_after_tusb) {
+    board_init_after_tusb();
+  }
+
   while (1)
   {
     tud_task(); // tinyusb device task
@@ -101,7 +105,7 @@ void tud_suspend_cb(bool remote_wakeup_en)
 // Invoked when usb bus is resumed
 void tud_resume_cb(void)
 {
-  blink_interval_ms = BLINK_MOUNTED;
+  blink_interval_ms = tud_mounted() ? BLINK_MOUNTED : BLINK_NOT_MOUNTED;
 }
 
 //--------------------------------------------------------------------+
diff --git a/examples/device/midi_test/src/usb_descriptors.c b/examples/device/midi_test/src/usb_descriptors.c
index 4845dcf57..9781d3d6f 100644
--- a/examples/device/midi_test/src/usb_descriptors.c
+++ b/examples/device/midi_test/src/usb_descriptors.c
@@ -23,13 +23,14 @@
  *
  */
 
+#include "bsp/board_api.h"
 #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]       MIDI | HID | MSC | CDC          [LSB]
+ *   [MSB]         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) | \
@@ -133,51 +134,63 @@ uint8_t const * tud_descriptor_configuration_cb(uint8_t index)
 // 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 [] =
+char const *string_desc_arr[] =
 {
   (const char[]) { 0x09, 0x04 }, // 0: is supported language is English (0x0409)
   "TinyUSB",                     // 1: Manufacturer
   "TinyUSB Device",              // 2: Product
-  "123456",                      // 3: Serials, should use chip ID
+  NULL,                          // 3: Serials will use unique ID if possible
 };
 
-static uint16_t _desc_str[32];
+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)
-{
+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;
 
-  uint8_t chr_count;
+    case STRID_SERIAL:
+      chr_count = board_usb_get_serial(_desc_str + 1, 32);
+      break;
 
-  if ( index == 0)
-  {
-    memcpy(&_desc_str[1], string_desc_arr[0], 2);
-    chr_count = 1;
-  }else
-  {
-    // 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
+    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;
+      if ( !(index < sizeof(string_desc_arr) / sizeof(string_desc_arr[0])) ) return NULL;
 
-    const char* str = string_desc_arr[index];
+      const char *str = string_desc_arr[index];
 
-    // Cap at max char
-    chr_count = (uint8_t) strlen(str);
-    if ( chr_count > 31 ) chr_count = 31;
+      // 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(uint8_t i=0; i<chr_count; i++)
-    {
-      _desc_str[1+i] = str[i];
-    }
+      // 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));
+  _desc_str[0] = (uint16_t) ((TUSB_DESC_STRING << 8) | (2 * chr_count + 2));
 
   return _desc_str;
 }
diff --git a/examples/device/msc_dual_lun/src/main.c b/examples/device/msc_dual_lun/src/main.c
index c7f6de7bf..de402d3da 100644
--- a/examples/device/msc_dual_lun/src/main.c
+++ b/examples/device/msc_dual_lun/src/main.c
@@ -27,7 +27,7 @@
 #include <stdio.h>
 #include <string.h>
 
-#include "bsp/board.h"
+#include "bsp/board_api.h"
 #include "tusb.h"
 
 //--------------------------------------------------------------------+
@@ -57,6 +57,10 @@ int main(void)
   // init device stack on configured roothub port
   tud_init(BOARD_TUD_RHPORT);
 
+  if (board_init_after_tusb) {
+    board_init_after_tusb();
+  }
+
   while (1)
   {
     tud_task(); // tinyusb device task
@@ -92,7 +96,7 @@ void tud_suspend_cb(bool remote_wakeup_en)
 // Invoked when usb bus is resumed
 void tud_resume_cb(void)
 {
-  blink_interval_ms = BLINK_MOUNTED;
+  blink_interval_ms = tud_mounted() ? BLINK_MOUNTED : BLINK_NOT_MOUNTED;
 }
 
 //--------------------------------------------------------------------+
diff --git a/examples/device/msc_dual_lun/src/msc_disk_dual.c b/examples/device/msc_dual_lun/src/msc_disk_dual.c
index b1047acdb..4f0f6410f 100644
--- a/examples/device/msc_dual_lun/src/msc_disk_dual.c
+++ b/examples/device/msc_dual_lun/src/msc_disk_dual.c
@@ -23,7 +23,7 @@
  *
  */
 
-#include "bsp/board.h"
+#include "bsp/board_api.h"
 #include "tusb.h"
 
 #if CFG_TUD_MSC
diff --git a/examples/device/msc_dual_lun/src/usb_descriptors.c b/examples/device/msc_dual_lun/src/usb_descriptors.c
index 2de81111c..c0610945f 100644
--- a/examples/device/msc_dual_lun/src/usb_descriptors.c
+++ b/examples/device/msc_dual_lun/src/usb_descriptors.c
@@ -23,6 +23,7 @@
  *
  */
 
+#include "bsp/board_api.h"
 #include "tusb.h"
 
 /* A combination of interfaces must have a unique product id, since PC will save device driver after the first plug.
@@ -141,51 +142,63 @@ uint8_t const * tud_descriptor_configuration_cb(uint8_t index)
 // 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 [] =
+char const *string_desc_arr[] =
 {
   (const char[]) { 0x09, 0x04 }, // 0: is supported language is English (0x0409)
   "TinyUSB",                     // 1: Manufacturer
   "TinyUSB Device",              // 2: Product
-  "123456789012",                // 3: Serials, should use chip ID
+  NULL,                          // 3: Serials will use unique ID if possible
 };
 
-static uint16_t _desc_str[32];
+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)
-{
+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;
 
-  uint8_t chr_count;
+    case STRID_SERIAL:
+      chr_count = board_usb_get_serial(_desc_str + 1, 32);
+      break;
 
-  if ( index == 0)
-  {
-    memcpy(&_desc_str[1], string_desc_arr[0], 2);
-    chr_count = 1;
-  }else
-  {
-    // 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
+    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;
+      if ( !(index < sizeof(string_desc_arr) / sizeof(string_desc_arr[0])) ) return NULL;
 
-    const char* str = string_desc_arr[index];
+      const char *str = string_desc_arr[index];
 
-    // Cap at max char
-    chr_count = (uint8_t) strlen(str);
-    if ( chr_count > 31 ) chr_count = 31;
+      // 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(uint8_t i=0; i<chr_count; i++)
-    {
-      _desc_str[1+i] = str[i];
-    }
+      // 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));
+  _desc_str[0] = (uint16_t) ((TUSB_DESC_STRING << 8) | (2 * chr_count + 2));
 
   return _desc_str;
 }
diff --git a/examples/device/net_lwip_webserver/CMakeLists.txt b/examples/device/net_lwip_webserver/CMakeLists.txt
index 1e34428fe..a16b8bd71 100644
--- a/examples/device/net_lwip_webserver/CMakeLists.txt
+++ b/examples/device/net_lwip_webserver/CMakeLists.txt
@@ -2,15 +2,15 @@ cmake_minimum_required(VERSION 3.17)
 
 include(${CMAKE_CURRENT_LIST_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})
+
 set(LWIP ${TOP}/lib/lwip)
 if (NOT EXISTS ${LWIP}/src)
-  MESSAGE(WARNING "lib/lwip submodule not found, please run 'python tools/get_deps.py lib/lwip' to fetch it")
+  family_example_missing_dependency(${PROJECT} "lib/lwip")
   return()
 endif()
 
-# 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
diff --git a/examples/device/net_lwip_webserver/src/main.c b/examples/device/net_lwip_webserver/src/main.c
index 19a0eae9d..7d98aacbc 100644
--- a/examples/device/net_lwip_webserver/src/main.c
+++ b/examples/device/net_lwip_webserver/src/main.c
@@ -43,7 +43,7 @@ The smartphone may be artificially picky about which Ethernet MAC address to rec
 try changing the first byte of tud_network_mac_address[] below from 0x02 to 0x00 (clearing bit 1).
 */
 
-#include "bsp/board.h"
+#include "bsp/board_api.h"
 #include "tusb.h"
 
 #include "dhserver.h"
@@ -232,6 +232,10 @@ int main(void)
   // init device stack on configured roothub port
   tud_init(BOARD_TUD_RHPORT);
 
+  if (board_init_after_tusb) {
+    board_init_after_tusb();
+  }
+
   /* initialize lwip, dhcp-server, dns-server, and http */
   init_lwip();
   while (!netif_is_up(&netif_data));
diff --git a/examples/device/net_lwip_webserver/src/usb_descriptors.c b/examples/device/net_lwip_webserver/src/usb_descriptors.c
index 3c0ed3db7..da628c8be 100644
--- a/examples/device/net_lwip_webserver/src/usb_descriptors.c
+++ b/examples/device/net_lwip_webserver/src/usb_descriptors.c
@@ -23,6 +23,7 @@
  *
  */
 
+#include "bsp/board_api.h"
 #include "tusb.h"
 
 /* A combination of interfaces must have a unique product id, since PC will save device driver after the first plug.
@@ -190,55 +191,56 @@ static char const* string_desc_arr [] =
   [STRID_LANGID]       = (const char[]) { 0x09, 0x04 }, // supported language is English (0x0409)
   [STRID_MANUFACTURER] = "TinyUSB",                     // Manufacturer
   [STRID_PRODUCT]      = "TinyUSB Device",              // Product
-  [STRID_SERIAL]       = "123456",                      // Serial
+  [STRID_SERIAL]       = NULL,                          // Serials will use unique ID if possible
   [STRID_INTERFACE]    = "TinyUSB Network Interface"    // Interface Description
 
   // STRID_MAC index is handled separately
 };
 
-static uint16_t _desc_str[32];
+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)
-{
+uint16_t const* tud_descriptor_string_cb(uint8_t index, uint16_t langid) {
   (void) langid;
-
   unsigned int chr_count = 0;
 
-  if (STRID_LANGID == index)
-  {
-    memcpy(&_desc_str[1], string_desc_arr[STRID_LANGID], 2);
-    chr_count = 1;
-  }
-  else if (STRID_MAC == index)
-  {
-    // Convert MAC address into UTF-16
+  switch ( index ) {
+    case STRID_LANGID:
+      memcpy(&_desc_str[1], string_desc_arr[0], 2);
+      chr_count = 1;
+      break;
 
-    for (unsigned i=0; i<sizeof(tud_network_mac_address); i++)
-    {
-      _desc_str[1+chr_count++] = "0123456789ABCDEF"[(tud_network_mac_address[i] >> 4) & 0xf];
-      _desc_str[1+chr_count++] = "0123456789ABCDEF"[(tud_network_mac_address[i] >> 0) & 0xf];
-    }
-  }
-  else
-  {
-    // 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
+    case STRID_SERIAL:
+      chr_count = board_usb_get_serial(_desc_str + 1, 32);
+      break;
+
+    case STRID_MAC:
+      // Convert MAC address into UTF-16
+      for (unsigned i=0; i<sizeof(tud_network_mac_address); i++) {
+        _desc_str[1+chr_count++] = "0123456789ABCDEF"[(tud_network_mac_address[i] >> 4) & 0xf];
+        _desc_str[1+chr_count++] = "0123456789ABCDEF"[(tud_network_mac_address[i] >> 0) & 0xf];
+      }
+      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;
+      if ( !(index < sizeof(string_desc_arr) / sizeof(string_desc_arr[0])) ) return NULL;
 
-    const char* str = string_desc_arr[index];
+      const char *str = string_desc_arr[index];
 
-    // Cap at max char
-    chr_count = (uint8_t) strlen(str);
-    if ( chr_count > (TU_ARRAY_SIZE(_desc_str) - 1)) chr_count = TU_ARRAY_SIZE(_desc_str) - 1;
+      // 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 (unsigned int i=0; i<chr_count; i++)
-    {
-      _desc_str[1+i] = str[i];
-    }
+      // 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
diff --git a/examples/device/uac2_headset/src/main.c b/examples/device/uac2_headset/src/main.c
index 19a3f7bae..0ab72b2f3 100644
--- a/examples/device/uac2_headset/src/main.c
+++ b/examples/device/uac2_headset/src/main.c
@@ -26,7 +26,7 @@
 #include <stdio.h>
 #include <string.h>
 
-#include "bsp/board.h"
+#include "bsp/board_api.h"
 #include "tusb.h"
 #include "usb_descriptors.h"
 
@@ -105,6 +105,10 @@ int main(void)
   // init device stack on configured roothub port
   tud_init(BOARD_TUD_RHPORT);
 
+  if (board_init_after_tusb) {
+    board_init_after_tusb();
+  }
+
   TU_LOG1("Headset running\r\n");
 
   while (1)
@@ -143,7 +147,7 @@ void tud_suspend_cb(bool remote_wakeup_en)
 // Invoked when usb bus is resumed
 void tud_resume_cb(void)
 {
-  blink_interval_ms = BLINK_MOUNTED;
+  blink_interval_ms = tud_mounted() ? BLINK_MOUNTED : BLINK_NOT_MOUNTED;
 }
 
 // Helper for clock get requests
diff --git a/examples/device/uac2_headset/src/usb_descriptors.c b/examples/device/uac2_headset/src/usb_descriptors.c
index 682774b72..6d1e6a23f 100644
--- a/examples/device/uac2_headset/src/usb_descriptors.c
+++ b/examples/device/uac2_headset/src/usb_descriptors.c
@@ -24,6 +24,7 @@
  *
  */
 
+#include "bsp/board_api.h"
 #include "tusb.h"
 #include "usb_descriptors.h"
 
@@ -126,52 +127,65 @@ uint8_t const * tud_descriptor_configuration_cb(uint8_t index)
 // 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 [] =
+char const *string_desc_arr[] =
 {
   (const char[]) { 0x09, 0x04 },  // 0: is supported language is English (0x0409)
   "TinyUSB",                      // 1: Manufacturer
   "TinyUSB headset",              // 2: Product
-  "000001",                       // 3: Serials, should use chip ID
+  NULL,                           // 3: Serials will use unique ID if possible
   "TinyUSB Speakers",             // 4: Audio Interface
   "TinyUSB Microphone",           // 5: Audio Interface
 };
 
-static uint16_t _desc_str[32];
+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;
+uint16_t const *tud_descriptor_string_cb(uint8_t index, uint16_t langid) {
+  (void) langid;
+  size_t chr_count;
 
-  uint8_t chr_count;
+  switch ( index ) {
+    case STRID_LANGID:
+      memcpy(&_desc_str[1], string_desc_arr[0], 2);
+      chr_count = 1;
+      break;
 
-  if (index == 0)
-  {
-    memcpy(&_desc_str[1], string_desc_arr[0], 2);
-    chr_count = 1;
-  }
-  else
-  {
-    // Convert ASCII string into UTF-16
+    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;
+      if ( !(index < sizeof(string_desc_arr) / sizeof(string_desc_arr[0])) ) return NULL;
 
-    const char* str = string_desc_arr[index];
+      const char *str = string_desc_arr[index];
 
-    // Cap at max char
-    chr_count = (uint8_t) strlen(str);
-    if (chr_count > 31) chr_count = 31;
+      // 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;
 
-    for (uint8_t i = 0; i < chr_count; i++)
-    {
-      _desc_str[1 + i] = str[i];
-    }
+      // 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));
+  _desc_str[0] = (uint16_t) ((TUSB_DESC_STRING << 8) | (2 * chr_count + 2));
 
   return _desc_str;
 }
diff --git a/examples/device/usbtmc/src/main.c b/examples/device/usbtmc/src/main.c
index 2bba336f1..9d8f0783d 100644
--- a/examples/device/usbtmc/src/main.c
+++ b/examples/device/usbtmc/src/main.c
@@ -27,7 +27,7 @@
 #include <stdio.h>
 #include <string.h>
 
-#include "bsp/board.h"
+#include "bsp/board_api.h"
 #include "tusb.h"
 #include "usbtmc_app.h"
 //--------------------------------------------------------------------+
@@ -57,6 +57,10 @@ int main(void)
   // init device stack on configured roothub port
   tud_init(BOARD_TUD_RHPORT);
 
+  if (board_init_after_tusb) {
+    board_init_after_tusb();
+  }
+
   while (1)
   {
     tud_task(); // tinyusb device task
@@ -93,7 +97,7 @@ void tud_suspend_cb(bool remote_wakeup_en)
 // Invoked when usb bus is resumed
 void tud_resume_cb(void)
 {
-  blink_interval_ms = BLINK_MOUNTED;
+  blink_interval_ms = tud_mounted() ? BLINK_MOUNTED : BLINK_NOT_MOUNTED;
 }
 
 //--------------------------------------------------------------------+
diff --git a/examples/device/usbtmc/src/usb_descriptors.c b/examples/device/usbtmc/src/usb_descriptors.c
index ff682ff97..54948291e 100644
--- a/examples/device/usbtmc/src/usb_descriptors.c
+++ b/examples/device/usbtmc/src/usb_descriptors.c
@@ -23,6 +23,7 @@
  *
  */
 
+#include "bsp/board_api.h"
 #include "tusb.h"
 #include "class/usbtmc/usbtmc.h"
 #include "class/usbtmc/usbtmc_device.h"
@@ -188,55 +189,64 @@ uint8_t const * tud_descriptor_configuration_cb(uint8_t index)
 // 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 [] =
+char const *string_desc_arr[] =
 {
   (const char[]) { 0x09, 0x04 }, // 0: is supported language is English (0x0409)
   "TinyUSB",                     // 1: Manufacturer
   "TinyUSB Device",              // 2: Product
-  "123456",                      // 3: Serials, should use chip ID
+  NULL,                          // 3: Serials will use unique ID if possible
   "TinyUSB USBTMC",              // 4: USBTMC
 };
 
-static uint16_t _desc_str[32];
+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)
-{
+uint16_t const *tud_descriptor_string_cb(uint8_t index, uint16_t langid) {
   (void) langid;
-
   size_t chr_count;
 
-  if ( index == 0)
-  {
-    memcpy(&_desc_str[1], string_desc_arr[0], 2);
-    chr_count = 1;
-  }
-  else
-  {
-    // 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
+  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;
+      if ( !(index < sizeof(string_desc_arr) / sizeof(string_desc_arr[0])) ) return NULL;
 
-    const char* str = string_desc_arr[index];
+      const char *str = string_desc_arr[index];
 
-    // Cap at max char
-    chr_count = (uint8_t) strlen(str);
-    if ( chr_count > 31 ) {
-      chr_count = 31;
-    }
+      // 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(uint8_t i=0; i<chr_count; i++)
-    {
-      _desc_str[1+i] = str[i];
-    }
+      // 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)((((uint16_t)TUSB_DESC_STRING) << 8 ) | (2u*chr_count + 2u));
+  _desc_str[0] = (uint16_t) ((TUSB_DESC_STRING << 8) | (2 * chr_count + 2));
 
   return _desc_str;
 }
diff --git a/examples/device/usbtmc/src/usbtmc_app.c b/examples/device/usbtmc/src/usbtmc_app.c
index 72989b4fe..fb25982c7 100644
--- a/examples/device/usbtmc/src/usbtmc_app.c
+++ b/examples/device/usbtmc/src/usbtmc_app.c
@@ -26,7 +26,7 @@
 #include <string.h>
 #include <stdlib.h>     /* atoi */
 #include "tusb.h"
-#include "bsp/board.h"
+#include "bsp/board_api.h"
 #include "main.h"
 
 #if (CFG_TUD_USBTMC_ENABLE_488)
diff --git a/examples/device/video_capture/src/main.c b/examples/device/video_capture/src/main.c
index 5654e0b61..c653761c1 100644
--- a/examples/device/video_capture/src/main.c
+++ b/examples/device/video_capture/src/main.c
@@ -27,7 +27,7 @@
 #include <stdio.h>
 #include <string.h>
 
-#include "bsp/board.h"
+#include "bsp/board_api.h"
 #include "tusb.h"
 #include "usb_descriptors.h"
 
@@ -59,6 +59,10 @@ int main(void)
   // init device stack on configured roothub port
   tud_init(BOARD_TUD_RHPORT);
 
+  if (board_init_after_tusb) {
+    board_init_after_tusb();
+  }
+
   while (1)
   {
     tud_task(); // tinyusb device task
@@ -96,7 +100,7 @@ void tud_suspend_cb(bool remote_wakeup_en)
 // Invoked when usb bus is resumed
 void tud_resume_cb(void)
 {
-  blink_interval_ms = BLINK_MOUNTED;
+  blink_interval_ms = tud_mounted() ? BLINK_MOUNTED : BLINK_NOT_MOUNTED;
 }
 
 
diff --git a/examples/device/video_capture/src/usb_descriptors.c b/examples/device/video_capture/src/usb_descriptors.c
index 9847cf7c5..292d86cd9 100644
--- a/examples/device/video_capture/src/usb_descriptors.c
+++ b/examples/device/video_capture/src/usb_descriptors.c
@@ -23,6 +23,7 @@
  *
  */
 
+#include "bsp/board_api.h"
 #include "tusb.h"
 #include "usb_descriptors.h"
 
@@ -150,52 +151,64 @@ uint8_t const * tud_descriptor_configuration_cb(uint8_t index)
 // 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 [] =
+char const *string_desc_arr[] =
 {
   (const char[]) { 0x09, 0x04 }, // 0: is supported language is English (0x0409)
   "TinyUSB",                     // 1: Manufacturer
   "TinyUSB Device",              // 2: Product
-  "123456",                      // 3: Serials, should use chip ID
+  NULL,                          // 3: Serials will use unique ID if possible
   "TinyUSB UVC",                 // 4: UVC Interface
 };
 
-static uint16_t _desc_str[32];
+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)
-{
+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;
 
-  uint8_t chr_count;
+    case STRID_SERIAL:
+      chr_count = board_usb_get_serial(_desc_str + 1, 32);
+      break;
 
-  if ( index == 0)
-  {
-    memcpy(&_desc_str[1], string_desc_arr[0], 2);
-    chr_count = 1;
-  }else
-  {
-    // 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
+    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;
+      if ( !(index < sizeof(string_desc_arr) / sizeof(string_desc_arr[0])) ) return NULL;
 
-    const char* str = string_desc_arr[index];
+      const char *str = string_desc_arr[index];
 
-    // Cap at max char
-    chr_count = (uint8_t) strlen(str);
-    if ( chr_count > 31 ) chr_count = 31;
+      // 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(uint8_t i=0; i<chr_count; i++)
-    {
-      _desc_str[1+i] = str[i];
-    }
+      // 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));
+  _desc_str[0] = (uint16_t) ((TUSB_DESC_STRING << 8) | (2 * chr_count + 2));
 
   return _desc_str;
 }
diff --git a/examples/device/webusb_serial/src/main.c b/examples/device/webusb_serial/src/main.c
index eaca78c73..800d435b8 100644
--- a/examples/device/webusb_serial/src/main.c
+++ b/examples/device/webusb_serial/src/main.c
@@ -47,7 +47,7 @@
 #include <stdio.h>
 #include <string.h>
 
-#include "bsp/board.h"
+#include "bsp/board_api.h"
 #include "tusb.h"
 #include "usb_descriptors.h"
 
@@ -96,6 +96,10 @@ int main(void)
   // init device stack on configured roothub port
   tud_init(BOARD_TUD_RHPORT);
 
+  if (board_init_after_tusb) {
+    board_init_after_tusb();
+  }
+
   while (1)
   {
     tud_task(); // tinyusb device task
@@ -156,7 +160,7 @@ void tud_suspend_cb(bool remote_wakeup_en)
 // Invoked when usb bus is resumed
 void tud_resume_cb(void)
 {
-  blink_interval_ms = BLINK_MOUNTED;
+  blink_interval_ms = tud_mounted() ? BLINK_MOUNTED : BLINK_NOT_MOUNTED;
 }
 
 //--------------------------------------------------------------------+
diff --git a/examples/device/webusb_serial/src/usb_descriptors.c b/examples/device/webusb_serial/src/usb_descriptors.c
index b2593001c..b01fae8e3 100644
--- a/examples/device/webusb_serial/src/usb_descriptors.c
+++ b/examples/device/webusb_serial/src/usb_descriptors.c
@@ -23,6 +23,7 @@
  *
  */
 
+#include "bsp/board_api.h"
 #include "tusb.h"
 #include "usb_descriptors.h"
 
@@ -207,53 +208,65 @@ TU_VERIFY_STATIC(sizeof(desc_ms_os_20) == MS_OS_20_DESC_LEN, "Incorrect size");
 // 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 [] =
+char const *string_desc_arr[] =
 {
   (const char[]) { 0x09, 0x04 }, // 0: is supported language is English (0x0409)
   "TinyUSB",                     // 1: Manufacturer
   "TinyUSB Device",              // 2: Product
-  "123456",                      // 3: Serials, should use chip ID
+  NULL,                          // 3: Serials will use unique ID if possible
   "TinyUSB CDC",                 // 4: CDC Interface
   "TinyUSB WebUSB"               // 5: Vendor Interface
 };
 
-static uint16_t _desc_str[32];
+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)
-{
+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;
 
-  uint8_t chr_count;
+    case STRID_SERIAL:
+      chr_count = board_usb_get_serial(_desc_str + 1, 32);
+      break;
 
-  if ( index == 0)
-  {
-    memcpy(&_desc_str[1], string_desc_arr[0], 2);
-    chr_count = 1;
-  }else
-  {
-    // 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
+    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;
+      if ( !(index < sizeof(string_desc_arr) / sizeof(string_desc_arr[0])) ) return NULL;
 
-    const char* str = string_desc_arr[index];
+      const char *str = string_desc_arr[index];
 
-    // Cap at max char
-    chr_count = (uint8_t) strlen(str);
-    if ( chr_count > 31 ) chr_count = 31;
+      // 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(uint8_t i=0; i<chr_count; i++)
-    {
-      _desc_str[1+i] = str[i];
-    }
+      // 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));
+  _desc_str[0] = (uint16_t) ((TUSB_DESC_STRING << 8) | (2 * chr_count + 2));
 
   return _desc_str;
 }