diff --git a/demos/device/device_os_none/cdcd_app.c b/demos/device/device_os_none/cdcd_app.c
index def783435..76acad9af 100644
--- a/demos/device/device_os_none/cdcd_app.c
+++ b/demos/device/device_os_none/cdcd_app.c
@@ -117,10 +117,10 @@ void tusbd_cdc_xfer_isr(uint8_t coreid, tusb_event_t event, cdc_pipeid_t pipe_id
 
 OSAL_TASK_FUNCTION( cdcd_serial_app_task ) (void* p_task_para)
 {
-  tusb_error_t error;
-
   OSAL_TASK_LOOP_BEGIN
 
+  tusb_error_t error;
+
   osal_semaphore_wait(sem_hdl, OSAL_TIMEOUT_WAIT_FOREVER, &error);
 
   if ( tusbd_cdc_is_configured(0) )
diff --git a/demos/device/device_os_none/keyboardd_app.c b/demos/device/device_os_none/keyboardd_app.c
index 130a9fa30..b6808400f 100644
--- a/demos/device/device_os_none/keyboardd_app.c
+++ b/demos/device/device_os_none/keyboardd_app.c
@@ -46,6 +46,8 @@
 //--------------------------------------------------------------------+
 // MACRO CONSTANT TYPEDEF
 //--------------------------------------------------------------------+
+OSAL_TASK_DEF(keyboardd_app_task, 128, KEYBOARDD_APP_TASK_PRIO);
+
 ATTR_USB_MIN_ALIGNMENT hid_keyboard_report_t keyboard_report TUSB_CFG_ATTR_USBRAM;
 
 //--------------------------------------------------------------------+
@@ -62,11 +64,13 @@ void tusbd_hid_keyboard_isr(uint8_t coreid, tusb_event_t event, uint32_t xferred
 
 void keyboardd_app_init(void)
 {
-
+  ASSERT( TUSB_ERROR_NONE == osal_task_create( OSAL_TASK_REF(keyboardd_app_task) ), VOID_RETURN);
 }
 
 OSAL_TASK_FUNCTION( keyboardd_app_task ) (void* p_task_para)
 {
+  OSAL_TASK_LOOP_BEGIN
+
   if (tusbd_is_configured(0))
   {
     static uint32_t count =0;
@@ -79,6 +83,10 @@ OSAL_TASK_FUNCTION( keyboardd_app_task ) (void* p_task_para)
       }
     }
   }
+
+  osal_task_delay(1000);
+
+  OSAL_TASK_LOOP_END
 }
 
 #endif
diff --git a/demos/device/device_os_none/moused_app.c b/demos/device/device_os_none/moused_app.c
index eb8814f7f..1551ee39c 100644
--- a/demos/device/device_os_none/moused_app.c
+++ b/demos/device/device_os_none/moused_app.c
@@ -50,6 +50,8 @@
 //--------------------------------------------------------------------+
 // INTERNAL OBJECT & FUNCTION DECLARATION
 //--------------------------------------------------------------------+
+OSAL_TASK_DEF(moused_app_task, 128, MOUSED_APP_TASK_PRIO);
+
 ATTR_USB_MIN_ALIGNMENT hid_mouse_report_t mouse_report TUSB_CFG_ATTR_USBRAM;
 
 //--------------------------------------------------------------------+
@@ -62,11 +64,13 @@ void tusbd_hid_mouse_isr(uint8_t coreid, tusb_event_t event, uint32_t xferred_by
 
 void moused_app_init(void)
 {
-
+  ASSERT( TUSB_ERROR_NONE == osal_task_create( OSAL_TASK_REF(moused_app_task) ), VOID_RETURN);
 }
 
 OSAL_TASK_FUNCTION( moused_app_task ) (void* p_task_para)
 {
+  OSAL_TASK_LOOP_BEGIN
+
   if (tusbd_is_configured(0))
   {
     static uint32_t count =0;
@@ -79,6 +83,10 @@ OSAL_TASK_FUNCTION( moused_app_task ) (void* p_task_para)
       }
     }
   }
+
+  osal_task_delay(1000);
+
+  OSAL_TASK_LOOP_END
 }
 
 #endif
diff --git a/demos/device/device_os_none/tusb_config.h b/demos/device/device_os_none/tusb_config.h
index 2d7ef1ff3..c2f17a4a9 100644
--- a/demos/device/device_os_none/tusb_config.h
+++ b/demos/device/device_os_none/tusb_config.h
@@ -81,17 +81,16 @@
 #define TUSB_CFG_DEVICE_FULLSPEED               1 // TODO refractor, remove
 
 //------------- CLASS -------------//
-#define TUSB_CFG_DEVICE_HID_KEYBOARD  0
-#define TUSB_CFG_DEVICE_HID_MOUSE     0
+#define TUSB_CFG_DEVICE_HID_KEYBOARD  1
+#define TUSB_CFG_DEVICE_HID_MOUSE     1
 #define TUSB_CFG_DEVICE_HID_GENERIC   0
 #define TUSB_CFG_DEVICE_MSC           1
-#define TUSB_CFG_DEVICE_CDC           0
+#define TUSB_CFG_DEVICE_CDC           1
 
 
 //--------------------------------------------------------------------+
 // COMMON CONFIGURATION
 //--------------------------------------------------------------------+
-
 #define TUSB_CFG_DEBUG                3
 
 #define TUSB_CFG_OS                   TUSB_OS_NONE // defined using eclipse build
diff --git a/tinyusb/class/cdc_device.c b/tinyusb/class/cdc_device.c
index 8c9cf1300..29f38c3f5 100644
--- a/tinyusb/class/cdc_device.c
+++ b/tinyusb/class/cdc_device.c
@@ -194,7 +194,7 @@ tusb_error_t cdcd_open(uint8_t coreid, tusb_descriptor_interface_t const * p_int
   return TUSB_ERROR_NONE;
 }
 
-void cdcd_bus_reset(uint8_t coreid)
+void cdcd_close(uint8_t coreid)
 {
   // no need to close opened pipe, dcd bus reset will put controller's endpoints to default state
   memclr_(&cdcd_data[coreid], sizeof(cdcd_data_t));
diff --git a/tinyusb/class/cdc_device.h b/tinyusb/class/cdc_device.h
index e1f298b76..03ad676f4 100644
--- a/tinyusb/class/cdc_device.h
+++ b/tinyusb/class/cdc_device.h
@@ -63,11 +63,13 @@ bool tusbd_cdc_is_busy(uint8_t coreid, cdc_pipeid_t pipeid)  ATTR_PURE ATTR_WARN
 tusb_error_t tusbd_cdc_send(uint8_t coreid, void * p_data, uint32_t length, bool is_notify);
 tusb_error_t tusbd_cdc_receive(uint8_t coreid, void * p_buffer, uint32_t length, bool is_notify);
 
-//------------- Callback -------------//
+//--------------------------------------------------------------------+
+// APPLICATION CALLBACK API
+//--------------------------------------------------------------------+
 void tusbd_cdc_mounted_cb(uint8_t coreid);
 void tusbd_cdc_unmounted_cb(uint8_t coreid);
 void tusbd_cdc_xfer_isr(uint8_t coreid, tusb_event_t event, cdc_pipeid_t pipe_id, uint32_t xferred_bytes);
-void tusbd_cdc_line_coding_changed_cb(uint8_t coreid, cdc_line_coding_t* p_line_coding);
+//void tusbd_cdc_line_coding_changed_cb(uint8_t coreid, cdc_line_coding_t* p_line_coding);
 
 //--------------------------------------------------------------------+
 // USBD-CLASS DRIVER API
@@ -76,9 +78,9 @@ void tusbd_cdc_line_coding_changed_cb(uint8_t coreid, cdc_line_coding_t* p_line_
 
 void cdcd_init(void);
 tusb_error_t cdcd_open(uint8_t coreid, tusb_descriptor_interface_t const * p_interface_desc, uint16_t *p_length);
-void cdcd_bus_reset(uint8_t coreid);
 tusb_error_t cdcd_control_request(uint8_t coreid, tusb_control_request_t const * p_request);
 void cdcd_isr(endpoint_handle_t edpt_hdl, tusb_event_t event, uint32_t xferred_bytes);
+void cdcd_close(uint8_t coreid);
 
 #endif
 
diff --git a/tinyusb/class/hid_device.c b/tinyusb/class/hid_device.c
index 662691946..4b184c9ad 100644
--- a/tinyusb/class/hid_device.c
+++ b/tinyusb/class/hid_device.c
@@ -124,7 +124,7 @@ void hidd_init(void)
   // TODO not implemented yet
 }
 
-void hidd_bus_reset(uint8_t coreid)
+void hidd_close(uint8_t coreid)
 {
   // TODO not implemented yet
 }
@@ -148,6 +148,8 @@ tusb_error_t hidd_control_request(uint8_t coreid, tusb_control_request_t const *
     uint8_t const desc_type  = u16_high_u8(p_request->wValue);
     uint8_t const desc_index = u16_low_u8 (p_request->wValue);
 
+    (void) desc_index;
+
     ASSERT ( p_request->bRequest == TUSB_REQUEST_GET_DESCRIPTOR && desc_type == HID_DESC_TYPE_REPORT,
              TUSB_ERROR_DCD_CONTROL_REQUEST_NOT_SUPPORT);
 
@@ -170,6 +172,9 @@ tusb_error_t hidd_control_request(uint8_t coreid, tusb_control_request_t const *
         hid_request_report_type_t report_type = u16_high_u8(p_request->wValue);
         uint8_t report_id = u16_low_u8(p_request->wValue);
 
+        (void) report_id;
+        (void) report_type;
+
         dcd_pipe_control_xfer(coreid, TUSB_DIR_HOST_TO_DEV, &set_report, p_request->wLength);
       }
       break;
diff --git a/tinyusb/class/hid_device.h b/tinyusb/class/hid_device.h
index 57cebaebb..ed50c8e75 100644
--- a/tinyusb/class/hid_device.h
+++ b/tinyusb/class/hid_device.h
@@ -49,13 +49,21 @@
 
 
 //--------------------------------------------------------------------+
-// KEYBOARD Application API
+// KEYBOARD APPLICATION API
 //--------------------------------------------------------------------+
 /** \addtogroup ClassDriver_HID_Keyboard Keyboard
  *  @{ */
 /** \defgroup Keyboard_Device Device
  *  @{ */
 
+/** \brief      Check if the interface is configured and ready to use
+ * \param[in]   coreid USB Controller ID
+ * \retval      true if the interface is configured
+ * \retval      false if the interface is not configured (e.g device is not attached)
+ * \note        This function should be call frequently or before any xfer attempt to check if device is still attached
+ */
+bool tusbd_hid_keyboard_is_configured(uint8_t coreid);
+
 /** \brief      Check if the interface is currently busy or not
  * \param[in]   coreid USB Controller ID
  * \retval      true if the interface is busy meaning the stack is still transferring/waiting data from/to host
@@ -77,7 +85,9 @@ bool tusbd_hid_keyboard_is_busy(uint8_t coreid);
  */
 tusb_error_t tusbd_hid_keyboard_send(uint8_t coreid, hid_keyboard_report_t const *p_report);
 
-//------------- Application Callback -------------//
+//--------------------------------------------------------------------+
+// APPLICATION CALLBACK API
+//--------------------------------------------------------------------+
 /** \brief      Callback function that is invoked when an transferring event occurred
  * \param[in]		coreid	USB Controller ID
  * \param[in]   event an value from \ref tusb_event_t
@@ -88,6 +98,8 @@ tusb_error_t tusbd_hid_keyboard_send(uint8_t coreid, hid_keyboard_report_t const
  * \note        Application should schedule the next report by calling \ref tusbh_hid_keyboard_get_report within this callback
  */
 void tusbd_hid_keyboard_isr(uint8_t coreid, tusb_event_t event, uint32_t xferred_bytes);
+void tusbd_hid_keyboard_mounted_cb(uint8_t coreid);
+void tusbd_hid_keyboard_unmounted_cb(uint8_t coreid);
 
 /** @} */
 /** @} */
@@ -100,6 +112,14 @@ void tusbd_hid_keyboard_isr(uint8_t coreid, tusb_event_t event, uint32_t xferred
 /** \defgroup Mouse_Device Device
  *  @{ */
 
+/** \brief      Check if the interface is configured and ready to use
+ * \param[in]   coreid USB Controller ID
+ * \retval      true if the interface is configured
+ * \retval      false if the interface is not configured (e.g device is not attached)
+ * \note        This function should be call frequently or before any xfer attempt to check if device is still attached
+ */
+bool tusbd_hid_mouse_is_configured(uint8_t coreid);
+
 /** \brief      Check if the interface is currently busy or not
  * \param[in]   coreid USB Controller ID
  * \retval      true if the interface is busy meaning the stack is still transferring/waiting data from/to host
@@ -121,7 +141,12 @@ bool tusbd_hid_mouse_is_busy(uint8_t coreid);
  */
 tusb_error_t tusbd_hid_mouse_send(uint8_t coreid, hid_mouse_report_t const *p_report);
 
+//--------------------------------------------------------------------+
+// APPLICATION CALLBACK API
+//--------------------------------------------------------------------+
 void tusbd_hid_mouse_isr(uint8_t coreid, tusb_event_t event, uint32_t xferred_bytes);
+void tusbd_hid_mouse_mounted_cb(uint8_t coreid);
+void tusbd_hid_mouse_unmounted_cb(uint8_t coreid);
 
 /** @} */
 /** @} */
@@ -134,10 +159,10 @@ void tusbd_hid_mouse_isr(uint8_t coreid, tusb_event_t event, uint32_t xferred_by
 #ifdef _TINY_USB_SOURCE_FILE_
 
 void hidd_init(void);
-void hidd_bus_reset(uint8_t coreid);
 tusb_error_t hidd_open(uint8_t coreid, tusb_descriptor_interface_t const * p_interface_desc, uint16_t *p_length);
 tusb_error_t hidd_control_request(uint8_t coreid, tusb_control_request_t const * p_request);
 void hidd_isr(endpoint_handle_t edpt_hdl, tusb_event_t event, uint32_t xferred_bytes);
+void hidd_close(uint8_t coreid);
 
 #endif
 
diff --git a/tinyusb/class/msc_device.c b/tinyusb/class/msc_device.c
index a975e759e..1ed33a3c9 100644
--- a/tinyusb/class/msc_device.c
+++ b/tinyusb/class/msc_device.c
@@ -75,7 +75,7 @@ void mscd_init(void)
   // TODO not implemented
 }
 
-void mscd_bus_reset(uint8_t coreid)
+void mscd_close(uint8_t coreid)
 {
   // TODO not implemented yet
 }
diff --git a/tinyusb/class/msc_device.h b/tinyusb/class/msc_device.h
index 3e6d9737f..5311a14f0 100644
--- a/tinyusb/class/msc_device.h
+++ b/tinyusb/class/msc_device.h
@@ -50,6 +50,20 @@
 //--------------------------------------------------------------------+
 // APPLICATION API
 //--------------------------------------------------------------------+
+/** \brief      Check if the interface is configured and ready to use
+ * \param[in]   coreid USB Controller ID
+ * \retval      true if the interface is configured
+ * \retval      false if the interface is not configured (e.g device is not attached)
+ * \note        This function should be call frequently or before any xfer attempt to check if device is still attached
+ */
+bool tusbd_msc_is_configured(uint8_t coreid);
+
+//--------------------------------------------------------------------+
+// APPLICATION CALLBACK API
+//--------------------------------------------------------------------+
+void tusbd_msc_mounted_cb(uint8_t coreid);
+void tusbd_msc_unmounted_cb(uint8_t coreid);
+
 // p_length [in,out] allocated/maximum length, application update with actual length
 msc_csw_status_t tusbd_msc_scsi_received_isr (uint8_t coreid, uint8_t lun, uint8_t scsi_cmd[16], void ** pp_buffer, uint16_t* p_length);
 
@@ -62,10 +76,10 @@ tusb_error_t tusbh_msc_write10(uint8_t dev_addr, uint8_t lun, void const * p_buf
 #ifdef _TINY_USB_SOURCE_FILE_
 
 void mscd_init(void);
-void mscd_bus_reset(uint8_t coreid);
 tusb_error_t mscd_open(uint8_t coreid, tusb_descriptor_interface_t const * p_interface_desc, uint16_t *p_length);
 tusb_error_t mscd_control_request(uint8_t coreid, tusb_control_request_t const * p_request);
 void mscd_isr(endpoint_handle_t edpt_hdl, tusb_event_t event, uint32_t xferred_bytes);
+void mscd_close(uint8_t coreid);
 
 #endif
 
diff --git a/tinyusb/device/dcd_lpc175x_6x.c b/tinyusb/device/dcd_lpc175x_6x.c
index ad04cea18..cebe31ea3 100644
--- a/tinyusb/device/dcd_lpc175x_6x.c
+++ b/tinyusb/device/dcd_lpc175x_6x.c
@@ -73,42 +73,6 @@ STATIC_ dcd_data_t dcd_data TUSB_CFG_ATTR_USBRAM;
 static void bus_reset(void);
 static tusb_error_t pipe_control_read(void * buffer, uint16_t length);
 
-//--------------------------------------------------------------------+
-// SIE Command
-//--------------------------------------------------------------------+
-static inline void sie_cmd_code (sie_cmdphase_t phase, uint8_t code_data) ATTR_ALWAYS_INLINE;
-static inline void sie_cmd_code (sie_cmdphase_t phase, uint8_t code_data)
-{
-  LPC_USB->USBDevIntClr = (DEV_INT_COMMAND_CODE_EMPTY_MASK | DEV_INT_COMMAND_DATA_FULL_MASK);
-  LPC_USB->USBCmdCode   = (phase << 8) | (code_data << 16);
-
-  uint32_t const wait_flag = (phase == SIE_CMDPHASE_READ) ? DEV_INT_COMMAND_DATA_FULL_MASK : DEV_INT_COMMAND_CODE_EMPTY_MASK;
-#ifndef _TEST_
-  while ((LPC_USB->USBDevIntSt & wait_flag) == 0); // TODO blocking forever potential
-#endif
-  LPC_USB->USBDevIntClr = wait_flag;
-}
-
-static inline void sie_write (uint8_t cmd_code, uint8_t data_len, uint8_t data) ATTR_ALWAYS_INLINE;
-static inline void sie_write (uint8_t cmd_code, uint8_t data_len, uint8_t data)
-{
-  sie_cmd_code(SIE_CMDPHASE_COMMAND, cmd_code);
-
-  if (data_len)
-  {
-    sie_cmd_code(SIE_CMDPHASE_WRITE, data);
-  }
-}
-
-static inline uint32_t sie_read (uint8_t cmd_code, uint8_t data_len) ATTR_ALWAYS_INLINE;
-static inline uint32_t sie_read (uint8_t cmd_code, uint8_t data_len)
-{
-  // TODO multiple read
-  sie_cmd_code(SIE_CMDPHASE_COMMAND , cmd_code);
-  sie_cmd_code(SIE_CMDPHASE_READ    , cmd_code);
-  return LPC_USB->USBCmdData;
-}
-
 //--------------------------------------------------------------------+
 // PIPE HELPER
 //--------------------------------------------------------------------+
@@ -239,22 +203,29 @@ void endpoint_control_isr(void)
 
 void dcd_isr(uint8_t coreid)
 {
+  (void) coreid;
   uint32_t const device_int_status = LPC_USB->USBDevIntSt & LPC_USB->USBDevIntEn;
   LPC_USB->USBDevIntClr = device_int_status;// Acknowledge handled interrupt
 
   //------------- usb bus event -------------//
   if (device_int_status & DEV_INT_DEVICE_STATUS_MASK)
   {
-    uint32_t const dev_status_reg = sie_read(SIE_CMDCODE_DEVICE_STATUS, 1);
+    uint8_t const dev_status_reg = sie_read(SIE_CMDCODE_DEVICE_STATUS, 1);
     if (dev_status_reg & SIE_DEV_STATUS_RESET_MASK)
     {
       bus_reset();
-      usbd_bus_reset(coreid);
+      usbd_dcd_bus_event_isr(0, USBD_BUS_EVENT_RESET);
     }
 
-    // TODO invoke some callbacks
-    if (dev_status_reg & SIE_DEV_STATUS_CONNECT_CHANGE_MASK) { }
-    if (dev_status_reg & SIE_DEV_STATUS_SUSPEND_CHANGE_MASK) { }
+    if ( (dev_status_reg & SIE_DEV_STATUS_CONNECT_CHANGE_MASK) && !(dev_status_reg & SIE_DEV_STATUS_CONNECT_STATUS_MASK))
+    { // device is disconnected, require using VBUS (P1_30)
+      usbd_dcd_bus_event_isr(0, USBD_BUS_EVENT_UNPLUGGED);
+    }
+
+    if ( (dev_status_reg & SIE_DEV_STATUS_SUSPEND_CHANGE_MASK) && (dev_status_reg & SIE_DEV_STATUS_SUSPEND_MASK) )
+    {
+      usbd_dcd_bus_event_isr(0, USBD_BUS_EVENT_SUSPENDED);
+    }
   }
 
   //------------- Control Endpoint (Slave Mode) -------------//
@@ -323,16 +294,19 @@ void dcd_isr(uint8_t coreid)
 //--------------------------------------------------------------------+
 void dcd_controller_connect(uint8_t coreid)
 {
+  (void) coreid;
   sie_write(SIE_CMDCODE_DEVICE_STATUS, 1, 1);
 }
 
 void dcd_controller_set_address(uint8_t coreid, uint8_t dev_addr)
 {
+  (void) coreid;
   sie_write(SIE_CMDCODE_SET_ADDRESS, 1, 0x80 | dev_addr); // 7th bit is : device_enable
 }
 
 void dcd_controller_set_configuration(uint8_t coreid)
 {
+  (void) coreid;
   sie_write(SIE_CMDCODE_CONFIGURE_DEVICE, 1, 1);
 }
 
diff --git a/tinyusb/device/dcd_lpc175x_6x.h b/tinyusb/device/dcd_lpc175x_6x.h
index aed21edeb..f66438702 100644
--- a/tinyusb/device/dcd_lpc175x_6x.h
+++ b/tinyusb/device/dcd_lpc175x_6x.h
@@ -161,7 +161,7 @@ enum {
 
 //------------- SIE Device Status (get/set from SIE_CMDCODE_DEVICE_STATUS) -------------//
 enum {
-  SIE_DEV_STATUS_CONNECT_MASK        = BIT_(0),
+  SIE_DEV_STATUS_CONNECT_STATUS_MASK = BIT_(0),
   SIE_DEV_STATUS_CONNECT_CHANGE_MASK = BIT_(1),
   SIE_DEV_STATUS_SUSPEND_MASK        = BIT_(2),
   SIE_DEV_STATUS_SUSPEND_CHANGE_MASK = BIT_(3),
@@ -196,6 +196,42 @@ enum {
   DD_STATUS_SYSTEM_ERROR
 };
 
+//--------------------------------------------------------------------+
+// SIE Command
+//--------------------------------------------------------------------+
+static inline void sie_cmd_code (sie_cmdphase_t phase, uint8_t code_data) ATTR_ALWAYS_INLINE;
+static inline void sie_cmd_code (sie_cmdphase_t phase, uint8_t code_data)
+{
+  LPC_USB->USBDevIntClr = (DEV_INT_COMMAND_CODE_EMPTY_MASK | DEV_INT_COMMAND_DATA_FULL_MASK);
+  LPC_USB->USBCmdCode   = (phase << 8) | (code_data << 16);
+
+  uint32_t const wait_flag = (phase == SIE_CMDPHASE_READ) ? DEV_INT_COMMAND_DATA_FULL_MASK : DEV_INT_COMMAND_CODE_EMPTY_MASK;
+#ifndef _TEST_
+  while ((LPC_USB->USBDevIntSt & wait_flag) == 0); // TODO blocking forever potential
+#endif
+  LPC_USB->USBDevIntClr = wait_flag;
+}
+
+static inline void sie_write (uint8_t cmd_code, uint8_t data_len, uint8_t data) ATTR_ALWAYS_INLINE;
+static inline void sie_write (uint8_t cmd_code, uint8_t data_len, uint8_t data)
+{
+  sie_cmd_code(SIE_CMDPHASE_COMMAND, cmd_code);
+
+  if (data_len)
+  {
+    sie_cmd_code(SIE_CMDPHASE_WRITE, data);
+  }
+}
+
+static inline uint32_t sie_read (uint8_t cmd_code, uint8_t data_len) ATTR_ALWAYS_INLINE;
+static inline uint32_t sie_read (uint8_t cmd_code, uint8_t data_len)
+{
+  // TODO multiple read
+  sie_cmd_code(SIE_CMDPHASE_COMMAND , cmd_code);
+  sie_cmd_code(SIE_CMDPHASE_READ    , cmd_code);
+  return LPC_USB->USBCmdData;
+}
+
 #ifdef __cplusplus
  }
 #endif
diff --git a/tinyusb/device/usbd.c b/tinyusb/device/usbd.c
index 328b881ea..aefdb78e1 100644
--- a/tinyusb/device/usbd.c
+++ b/tinyusb/device/usbd.c
@@ -71,7 +71,7 @@ static usbd_class_driver_t const usbd_class_drivers[TUSB_CLASS_MAPPED_INDEX_STAR
         .open            = hidd_open,
         .control_request = hidd_control_request,
         .isr             = hidd_isr,
-        .bus_reset       = hidd_bus_reset
+        .close           = hidd_close
     },
 #endif
 
@@ -82,7 +82,7 @@ static usbd_class_driver_t const usbd_class_drivers[TUSB_CLASS_MAPPED_INDEX_STAR
         .open            = mscd_open,
         .control_request = mscd_control_request,
         .isr             = mscd_isr,
-        .bus_reset       = mscd_bus_reset
+        .close           = mscd_close
     },
 #endif
 
@@ -93,7 +93,7 @@ static usbd_class_driver_t const usbd_class_drivers[TUSB_CLASS_MAPPED_INDEX_STAR
         .open            = cdcd_open,
         .control_request = cdcd_control_request,
         .isr             = cdcd_isr,
-        .bus_reset       = cdcd_bus_reset
+        .close           = cdcd_close
     },
 #endif
 
@@ -251,19 +251,6 @@ OSAL_TASK_FUNCTION(usbd_task) (void* p_task_para)
   OSAL_TASK_LOOP_END
 }
 
-void usbd_bus_reset(uint32_t coreid)
-{
-  memclr_(&usbd_devices[coreid], sizeof(usbd_device_info_t));
-
-  for (tusb_std_class_code_t class_code = TUSB_CLASS_AUDIO; class_code <= TUSB_CLASS_AUDIO_VIDEO; class_code++)
-  {
-    if ( usbd_class_drivers[class_code].bus_reset )
-    {
-      usbd_class_drivers[class_code].bus_reset( coreid );
-    }
-  }
-}
-
 tusb_error_t usbd_init (void)
 {
   ASSERT_STATUS ( dcd_init() );
@@ -368,8 +355,29 @@ tusb_error_t get_descriptor_subtask(uint8_t coreid, tusb_control_request_t * p_r
 //--------------------------------------------------------------------+
 
 //--------------------------------------------------------------------+
-// DCD Callback API
+// USBD-DCD Callback API
 //--------------------------------------------------------------------+
+void usbd_dcd_bus_event_isr(uint8_t coreid, usbd_bus_event_type_t bus_event)
+{
+  switch(bus_event)
+  {
+    case USBD_BUS_EVENT_RESET     :
+    case USBD_BUS_EVENT_UNPLUGGED :
+      memclr_(&usbd_devices[coreid], sizeof(usbd_device_info_t));
+      for (tusb_std_class_code_t class_code = TUSB_CLASS_AUDIO; class_code <= TUSB_CLASS_AUDIO_VIDEO; class_code++)
+      {
+        if ( usbd_class_drivers[class_code].close ) usbd_class_drivers[class_code].close( coreid );
+      }
+    break;
+
+    case USBD_BUS_EVENT_SUSPENDED:
+      usbd_devices[coreid].state = TUSB_DEVICE_STATE_SUSPENDED;
+    break;
+
+    default: break;
+  }
+}
+
 void usbd_setup_received_isr(uint8_t coreid, tusb_control_request_t * p_request)
 {
   usbd_devices[coreid].control_request = (*p_request);
diff --git a/tinyusb/device/usbd.h b/tinyusb/device/usbd.h
index e8e10e98b..d9b74c788 100644
--- a/tinyusb/device/usbd.h
+++ b/tinyusb/device/usbd.h
@@ -72,7 +72,7 @@ typedef struct {
   tusb_error_t (* const open)(uint8_t, tusb_descriptor_interface_t const *, uint16_t*);
   tusb_error_t (* const control_request) (uint8_t, tusb_control_request_t const *);
   void (* const isr) (endpoint_handle_t, tusb_event_t, uint32_t);
-  void (* const bus_reset) (uint8_t);
+  void (* const close) (uint8_t);
 } usbd_class_driver_t;
 
 //--------------------------------------------------------------------+
diff --git a/tinyusb/device/usbd_dcd.h b/tinyusb/device/usbd_dcd.h
index e72cdf060..8fbcc317c 100644
--- a/tinyusb/device/usbd_dcd.h
+++ b/tinyusb/device/usbd_dcd.h
@@ -55,24 +55,31 @@
  extern "C" {
 #endif
 
-#define USBD_MAX_INTERFACE  16 // TODO refractor later
-#define USBD_MAX_ENDPOINT   32 // TODO refractor later
+enum {
+  USBD_INTERFACE_NUM_MAX = 16 // USB specs specify up to 16 endpoints per device
+};
 
+typedef enum {
+  USBD_BUS_EVENT_RESET = 1,
+  USBD_BUS_EVENT_UNPLUGGED,
+  USBD_BUS_EVENT_SUSPENDED
+}usbd_bus_event_type_t;
 
 typedef struct {
   volatile uint8_t state;
   uint8_t is_waiting_control_xfer;             // set if task is waiting for control xfer to complete to proceed
   tusb_control_request_t control_request;
-  uint8_t interface2class[USBD_MAX_INTERFACE]; // determine interface number belongs to which class
+  uint8_t interface2class[USBD_INTERFACE_NUM_MAX]; // determine interface number belongs to which class
 }usbd_device_info_t;
 
 extern usbd_device_info_t usbd_devices[CONTROLLER_DEVICE_NUMBER];
 //--------------------------------------------------------------------+
 // callback from DCD ISR
 //--------------------------------------------------------------------+
-void usbd_xfer_isr(endpoint_handle_t edpt_hdl, tusb_event_t event, uint32_t xferred_bytes);
-void usbd_bus_reset(uint32_t coreid);
+void usbd_dcd_bus_event_isr(uint8_t coreid, usbd_bus_event_type_t bus_event);
 void usbd_setup_received_isr(uint8_t coreid, tusb_control_request_t * p_request);
+void usbd_xfer_isr(endpoint_handle_t edpt_hdl, tusb_event_t event, uint32_t xferred_bytes);
+
 
 #ifdef __cplusplus
  }