diff --git a/examples/obsolete/device/src/keyboard_device_app.c b/examples/obsolete/device/src/keyboard_device_app.c
index f6ef77c10..6c413464e 100644
--- a/examples/obsolete/device/src/keyboard_device_app.c
+++ b/examples/obsolete/device/src/keyboard_device_app.c
@@ -66,7 +66,7 @@ void keyboard_app_umount(uint8_t rhport)
 
 }
 
-void tud_hid_keyboard_cb(uint8_t rhport, tusb_event_t event, uint32_t xferred_bytes)
+void tud_hid_keyboard_cb(uint8_t rhport, xfer_result_t event, uint32_t xferred_bytes)
 {
   switch(event)
   {
diff --git a/examples/obsolete/device/src/mouse_device_app.c b/examples/obsolete/device/src/mouse_device_app.c
index db685daf6..4c4d322d7 100644
--- a/examples/obsolete/device/src/mouse_device_app.c
+++ b/examples/obsolete/device/src/mouse_device_app.c
@@ -66,7 +66,7 @@ void mouse_app_umount(uint8_t rhport)
 
 }
 
-void tud_hid_mouse_cb(uint8_t rhport, tusb_event_t event, uint32_t xferred_bytes)
+void tud_hid_mouse_cb(uint8_t rhport, xfer_result_t event, uint32_t xferred_bytes)
 {
   switch(event)
   {
diff --git a/examples/obsolete/host/src/cdc_serial_host_app.c b/examples/obsolete/host/src/cdc_serial_host_app.c
index d16a9b411..afb2b8937 100644
--- a/examples/obsolete/host/src/cdc_serial_host_app.c
+++ b/examples/obsolete/host/src/cdc_serial_host_app.c
@@ -75,7 +75,7 @@ void tuh_cdc_unmounted_cb(uint8_t dev_addr)
 }
 
 // invoked ISR context
-void tuh_cdc_xfer_isr(uint8_t dev_addr, tusb_event_t event, cdc_pipeid_t pipe_id, uint32_t xferred_bytes)
+void tuh_cdc_xfer_isr(uint8_t dev_addr, xfer_result_t event, cdc_pipeid_t pipe_id, uint32_t xferred_bytes)
 {
   (void) dev_addr; // compiler warnings
 
diff --git a/examples/obsolete/host/src/keyboard_host_app.c b/examples/obsolete/host/src/keyboard_host_app.c
index 6d10e96e1..27d10b9e7 100644
--- a/examples/obsolete/host/src/keyboard_host_app.c
+++ b/examples/obsolete/host/src/keyboard_host_app.c
@@ -77,7 +77,7 @@ void tuh_hid_keyboard_unmounted_cb(uint8_t dev_addr)
 }
 
 // invoked ISR context
-void tuh_hid_keyboard_isr(uint8_t dev_addr, tusb_event_t event)
+void tuh_hid_keyboard_isr(uint8_t dev_addr, xfer_result_t event)
 {
   switch(event)
   {
diff --git a/examples/obsolete/host/src/mouse_host_app.c b/examples/obsolete/host/src/mouse_host_app.c
index 563b911c2..05135693b 100644
--- a/examples/obsolete/host/src/mouse_host_app.c
+++ b/examples/obsolete/host/src/mouse_host_app.c
@@ -76,7 +76,7 @@ void tuh_hid_mouse_unmounted_cb(uint8_t dev_addr)
 }
 
 // invoked ISR context
-void tuh_hid_mouse_isr(uint8_t dev_addr, tusb_event_t event)
+void tuh_hid_mouse_isr(uint8_t dev_addr, xfer_result_t event)
 {
   switch(event)
   {
diff --git a/examples/obsolete/host/src/msc_host_app.c b/examples/obsolete/host/src/msc_host_app.c
index 3648cb94b..1cfe9ec60 100644
--- a/examples/obsolete/host/src/msc_host_app.c
+++ b/examples/obsolete/host/src/msc_host_app.c
@@ -129,7 +129,7 @@ void tuh_msc_unmounted_cb(uint8_t dev_addr)
 }
 
 // invoked ISR context
-void tuh_msc_isr(uint8_t dev_addr, tusb_event_t event, uint32_t xferred_bytes)
+void tuh_msc_isr(uint8_t dev_addr, xfer_result_t event, uint32_t xferred_bytes)
 {
   (void) dev_addr;
   (void) event;
diff --git a/src/class/cdc/cdc_device.c b/src/class/cdc/cdc_device.c
index a0abd42f6..b68a6a7ff 100644
--- a/src/class/cdc/cdc_device.c
+++ b/src/class/cdc/cdc_device.c
@@ -358,7 +358,7 @@ bool cdcd_control_request(uint8_t rhport, tusb_control_request_t const * request
   return true;
 }
 
-tusb_error_t cdcd_xfer_cb(uint8_t rhport, uint8_t ep_addr, tusb_event_t event, uint32_t xferred_bytes)
+tusb_error_t cdcd_xfer_cb(uint8_t rhport, uint8_t ep_addr, xfer_result_t event, uint32_t xferred_bytes)
 {
   // TODO Support multiple interfaces
   uint8_t const itf = 0;
diff --git a/src/class/cdc/cdc_device.h b/src/class/cdc/cdc_device.h
index 749351a54..ad1100e9c 100644
--- a/src/class/cdc/cdc_device.h
+++ b/src/class/cdc/cdc_device.h
@@ -116,7 +116,7 @@ void         cdcd_init               (void);
 tusb_error_t cdcd_open               (uint8_t rhport, tusb_desc_interface_t const * p_interface_desc, uint16_t *p_length);
 bool cdcd_control_request (uint8_t rhport, tusb_control_request_t const * p_request);
 bool cdcd_control_request_complete (uint8_t rhport, tusb_control_request_t const * p_request);
-tusb_error_t cdcd_xfer_cb            (uint8_t rhport, uint8_t edpt_addr, tusb_event_t event, uint32_t xferred_bytes);
+tusb_error_t cdcd_xfer_cb            (uint8_t rhport, uint8_t edpt_addr, xfer_result_t event, uint32_t xferred_bytes);
 void         cdcd_reset              (uint8_t rhport);
 
 #endif
diff --git a/src/class/cdc/cdc_host.c b/src/class/cdc/cdc_host.c
index af2e2c444..0a3661878 100644
--- a/src/class/cdc/cdc_host.c
+++ b/src/class/cdc/cdc_host.c
@@ -221,7 +221,7 @@ tusb_error_t cdch_open_subtask(uint8_t dev_addr, tusb_desc_interface_t const *p_
   OSAL_SUBTASK_END
 }
 
-void cdch_isr(pipe_handle_t pipe_hdl, tusb_event_t event, uint32_t xferred_bytes)
+void cdch_isr(pipe_handle_t pipe_hdl, xfer_result_t event, uint32_t xferred_bytes)
 {
   tuh_cdc_xfer_isr( pipe_hdl.dev_addr, event, get_app_pipeid(pipe_hdl), xferred_bytes );
 }
diff --git a/src/class/cdc/cdc_host.h b/src/class/cdc/cdc_host.h
index b3e995470..8cfe6e5b7 100644
--- a/src/class/cdc/cdc_host.h
+++ b/src/class/cdc/cdc_host.h
@@ -118,7 +118,7 @@ void tuh_cdc_unmounted_cb(uint8_t dev_addr);
 
 /** \brief      Callback function that is invoked when an transferring event occurred
  * \param[in]		dev_addr	Address of device
- * \param[in]   event an value from \ref tusb_event_t
+ * \param[in]   event an value from \ref xfer_result_t
  * \param[in]   pipe_id value from \ref cdc_pipeid_t indicate the pipe
  * \param[in]   xferred_bytes Number of bytes transferred via USB bus
  * \note        event can be one of following
@@ -127,7 +127,7 @@ void tuh_cdc_unmounted_cb(uint8_t dev_addr);
  *              - TUSB_EVENT_XFER_STALLED : previously scheduled transfer is stalled by device.
  * \note
  */
-void tuh_cdc_xfer_isr(uint8_t dev_addr, tusb_event_t event, cdc_pipeid_t pipe_id, uint32_t xferred_bytes);
+void tuh_cdc_xfer_isr(uint8_t dev_addr, xfer_result_t event, cdc_pipeid_t pipe_id, uint32_t xferred_bytes);
 
 /// @} // group CDC_Serial_Host
 /// @}
@@ -151,7 +151,7 @@ extern cdch_data_t cdch_data[CFG_TUSB_HOST_DEVICE_MAX]; // TODO consider to move
 
 void         cdch_init(void);
 tusb_error_t cdch_open_subtask(uint8_t dev_addr, tusb_desc_interface_t const *p_interface_desc, uint16_t *p_length) ATTR_WARN_UNUSED_RESULT;
-void         cdch_isr(pipe_handle_t pipe_hdl, tusb_event_t event, uint32_t xferred_bytes);
+void         cdch_isr(pipe_handle_t pipe_hdl, xfer_result_t event, uint32_t xferred_bytes);
 void         cdch_close(uint8_t dev_addr);
 
 #endif
diff --git a/src/class/cdc/cdc_rndis_host.c b/src/class/cdc/cdc_rndis_host.c
index 42722fd0d..89ea3b32f 100644
--- a/src/class/cdc/cdc_rndis_host.c
+++ b/src/class/cdc/cdc_rndis_host.c
@@ -224,7 +224,7 @@ tusb_error_t rndish_open_subtask(uint8_t dev_addr, cdch_data_t *p_cdc)
   OSAL_SUBTASK_END
 }
 
-void rndish_xfer_isr(cdch_data_t *p_cdc, pipe_handle_t pipe_hdl, tusb_event_t event, uint32_t xferred_bytes)
+void rndish_xfer_isr(cdch_data_t *p_cdc, pipe_handle_t pipe_hdl, xfer_result_t event, uint32_t xferred_bytes)
 {
   if ( pipehandle_is_equal(pipe_hdl, p_cdc->pipe_notification) )
   {
diff --git a/src/class/cdc/cdc_rndis_host.h b/src/class/cdc/cdc_rndis_host.h
index c4597daa8..3b92d3f23 100644
--- a/src/class/cdc/cdc_rndis_host.h
+++ b/src/class/cdc/cdc_rndis_host.h
@@ -65,7 +65,7 @@ typedef struct {
 
 void rndish_init(void);
 tusb_error_t rndish_open_subtask(uint8_t dev_addr, cdch_data_t *p_cdc) ATTR_WARN_UNUSED_RESULT;
-void rndish_xfer_isr(cdch_data_t *p_cdc, pipe_handle_t pipe_hdl, tusb_event_t event, uint32_t xferred_bytes);
+void rndish_xfer_isr(cdch_data_t *p_cdc, pipe_handle_t pipe_hdl, xfer_result_t event, uint32_t xferred_bytes);
 void rndish_close(uint8_t dev_addr);
 
 #endif
diff --git a/src/class/custom/custom_device.c b/src/class/custom/custom_device.c
index cc440fc7e..194963c17 100644
--- a/src/class/custom/custom_device.c
+++ b/src/class/custom/custom_device.c
@@ -94,7 +94,7 @@ bool cusd_control_request(uint8_t rhport, tusb_control_request_t const * p_reque
   return false;
 }
 
-tusb_error_t cusd_xfer_cb(uint8_t rhport, uint8_t edpt_addr, tusb_event_t event, uint32_t xferred_bytes)
+tusb_error_t cusd_xfer_cb(uint8_t rhport, uint8_t edpt_addr, xfer_result_t event, uint32_t xferred_bytes)
 {
   return TUSB_ERROR_NONE;
 }
diff --git a/src/class/custom/custom_device.h b/src/class/custom/custom_device.h
index 704c4127b..0a8f05e7d 100644
--- a/src/class/custom/custom_device.h
+++ b/src/class/custom/custom_device.h
@@ -66,7 +66,7 @@ void cusd_init(void);
 tusb_error_t cusd_open(uint8_t rhport, tusb_desc_interface_t const * p_interface_desc, uint16_t *p_length);
 bool cusd_control_request_st(uint8_t rhport, tusb_control_request_t const * p_request);
 bool cusd_control_request_complete (uint8_t rhport, tusb_control_request_t const * p_request);
-tusb_error_t cusd_xfer_cb(uint8_t rhport, uint8_t edpt_addr, tusb_event_t event, uint32_t xferred_bytes);
+tusb_error_t cusd_xfer_cb(uint8_t rhport, uint8_t edpt_addr, xfer_result_t event, uint32_t xferred_bytes);
 void cusd_reset(uint8_t rhport);
 #endif
 
diff --git a/src/class/custom/custom_host.c b/src/class/custom/custom_host.c
index 329012fda..9f0b70afb 100644
--- a/src/class/custom/custom_host.c
+++ b/src/class/custom/custom_host.c
@@ -131,7 +131,7 @@ tusb_error_t cush_open_subtask(uint8_t dev_addr, tusb_desc_interface_t const *p_
   return TUSB_ERROR_NONE;
 }
 
-void cush_isr(pipe_handle_t pipe_hdl, tusb_event_t event)
+void cush_isr(pipe_handle_t pipe_hdl, xfer_result_t event)
 {
 
 }
diff --git a/src/class/custom/custom_host.h b/src/class/custom/custom_host.h
index 2bf3a8d3c..5f9c25dda 100644
--- a/src/class/custom/custom_host.h
+++ b/src/class/custom/custom_host.h
@@ -73,7 +73,7 @@ tusb_error_t tusbh_custom_write(uint8_t dev_addr, uint16_t vendor_id, uint16_t p
 
 void         cush_init(void);
 tusb_error_t cush_open_subtask(uint8_t dev_addr, tusb_desc_interface_t const *p_interface_desc, uint16_t *p_length) ATTR_WARN_UNUSED_RESULT;
-void         cush_isr(pipe_handle_t pipe_hdl, tusb_event_t event);
+void         cush_isr(pipe_handle_t pipe_hdl, xfer_result_t event);
 void         cush_close(uint8_t dev_addr);
 
 #endif
diff --git a/src/class/hid/hid_device.c b/src/class/hid/hid_device.c
index cece06ea0..f1ecec3c7 100644
--- a/src/class/hid/hid_device.c
+++ b/src/class/hid/hid_device.c
@@ -510,7 +510,7 @@ bool hidd_control_request_complete(uint8_t rhport, tusb_control_request_t const
   return true;
 }
 
-tusb_error_t hidd_xfer_cb(uint8_t rhport, uint8_t edpt_addr, tusb_event_t event, uint32_t xferred_bytes)
+tusb_error_t hidd_xfer_cb(uint8_t rhport, uint8_t edpt_addr, xfer_result_t event, uint32_t xferred_bytes)
 {
   // nothing to do
   return TUSB_ERROR_NONE;
diff --git a/src/class/hid/hid_device.h b/src/class/hid/hid_device.h
index 357c71082..7aff7f34d 100644
--- a/src/class/hid/hid_device.h
+++ b/src/class/hid/hid_device.h
@@ -380,7 +380,7 @@ void hidd_init(void);
 tusb_error_t hidd_open(uint8_t rhport, tusb_desc_interface_t const * p_interface_desc, uint16_t *p_length);
 bool hidd_control_request(uint8_t rhport, tusb_control_request_t const * p_request);
 bool hidd_control_request_complete (uint8_t rhport, tusb_control_request_t const * p_request);
-tusb_error_t hidd_xfer_cb(uint8_t rhport, uint8_t edpt_addr, tusb_event_t event, uint32_t xferred_bytes);
+tusb_error_t hidd_xfer_cb(uint8_t rhport, uint8_t edpt_addr, xfer_result_t event, uint32_t xferred_bytes);
 void hidd_reset(uint8_t rhport);
 
 #endif
diff --git a/src/class/hid/hid_host.c b/src/class/hid/hid_host.c
index 7129562c5..6aa0748df 100644
--- a/src/class/hid/hid_host.c
+++ b/src/class/hid/hid_host.c
@@ -251,7 +251,7 @@ tusb_error_t hidh_open_subtask(uint8_t dev_addr, tusb_desc_interface_t const *p_
   OSAL_SUBTASK_END
 }
 
-void hidh_isr(pipe_handle_t pipe_hdl, tusb_event_t event, uint32_t xferred_bytes)
+void hidh_isr(pipe_handle_t pipe_hdl, xfer_result_t event, uint32_t xferred_bytes)
 {
   (void) xferred_bytes; // TODO may need to use this para later
 
diff --git a/src/class/hid/hid_host.h b/src/class/hid/hid_host.h
index 3acc05bf7..fb10a614f 100644
--- a/src/class/hid/hid_host.h
+++ b/src/class/hid/hid_host.h
@@ -93,14 +93,14 @@ tusb_error_t  tuh_hid_keyboard_get_report(uint8_t dev_addr, void * p_report) /*A
 //------------- Application Callback -------------//
 /** \brief      Callback function that is invoked when an transferring event occurred
  * \param[in]		dev_addr	Address of device
- * \param[in]   event an value from \ref tusb_event_t
+ * \param[in]   event an value from \ref xfer_result_t
  * \note        event can be one of following
  *              - TUSB_EVENT_XFER_COMPLETE : previously scheduled transfer completes successfully.
  *              - TUSB_EVENT_XFER_ERROR   : previously scheduled transfer encountered a transaction error.
  *              - TUSB_EVENT_XFER_STALLED : previously scheduled transfer is stalled by device.
  * \note        Application should schedule the next report by calling \ref tuh_hid_keyboard_get_report within this callback
  */
-void tuh_hid_keyboard_isr(uint8_t dev_addr, tusb_event_t event);
+void tuh_hid_keyboard_isr(uint8_t dev_addr, xfer_result_t event);
 
 /** \brief 			Callback function that will be invoked when a device with Keyboard interface is mounted
  * \param[in] 	dev_addr Address of newly mounted device
@@ -158,14 +158,14 @@ tusb_error_t  tuh_hid_mouse_get_report(uint8_t dev_addr, void* p_report) /*ATTR_
 //------------- Application Callback -------------//
 /** \brief      Callback function that is invoked when an transferring event occurred
  * \param[in]		dev_addr	Address of device
- * \param[in]   event an value from \ref tusb_event_t
+ * \param[in]   event an value from \ref xfer_result_t
  * \note        event can be one of following
  *              - TUSB_EVENT_XFER_COMPLETE : previously scheduled transfer completes successfully.
  *              - TUSB_EVENT_XFER_ERROR   : previously scheduled transfer encountered a transaction error.
  *              - TUSB_EVENT_XFER_STALLED : previously scheduled transfer is stalled by device.
  * \note        Application should schedule the next report by calling \ref tuh_hid_mouse_get_report within this callback
  */
-void tuh_hid_mouse_isr(uint8_t dev_addr, tusb_event_t event);
+void tuh_hid_mouse_isr(uint8_t dev_addr, xfer_result_t event);
 
 /** \brief 			Callback function that will be invoked when a device with Mouse interface is mounted
  * \param[in]	  dev_addr Address of newly mounted device
@@ -199,7 +199,7 @@ tusb_interface_status_t tuh_hid_generic_get_status(uint8_t dev_addr) ATTR_WARN_U
 tusb_interface_status_t tuh_hid_generic_set_status(uint8_t dev_addr) ATTR_WARN_UNUSED_RESULT;
 
 //------------- Application Callback -------------//
-void tuh_hid_generic_isr(uint8_t dev_addr, tusb_event_t event);
+void tuh_hid_generic_isr(uint8_t dev_addr, xfer_result_t event);
 
 /** @} */ // Generic_Host
 /** @} */ // ClassDriver_HID_Generic
@@ -217,7 +217,7 @@ typedef struct {
 
 void         hidh_init(void);
 tusb_error_t hidh_open_subtask(uint8_t dev_addr, tusb_desc_interface_t const *p_interface_desc, uint16_t *p_length) ATTR_WARN_UNUSED_RESULT;
-void         hidh_isr(pipe_handle_t pipe_hdl, tusb_event_t event, uint32_t xferred_bytes);
+void         hidh_isr(pipe_handle_t pipe_hdl, xfer_result_t event, uint32_t xferred_bytes);
 void         hidh_close(uint8_t dev_addr);
 
 #endif
diff --git a/src/class/msc/msc_device.c b/src/class/msc/msc_device.c
index 78e6d0a6b..1f4252f22 100644
--- a/src/class/msc/msc_device.c
+++ b/src/class/msc/msc_device.c
@@ -324,7 +324,7 @@ int32_t proc_builtin_scsi(msc_cbw_t const * p_cbw, uint8_t* buffer, uint32_t buf
   return ret;
 }
 
-tusb_error_t mscd_xfer_cb(uint8_t rhport, uint8_t ep_addr, tusb_event_t event, uint32_t xferred_bytes)
+tusb_error_t mscd_xfer_cb(uint8_t rhport, uint8_t ep_addr, xfer_result_t event, uint32_t xferred_bytes)
 {
   mscd_interface_t* p_msc = &_mscd_itf;
   msc_cbw_t const * p_cbw = &p_msc->cbw;
@@ -337,7 +337,7 @@ tusb_error_t mscd_xfer_cb(uint8_t rhport, uint8_t ep_addr, tusb_event_t event, u
       // Complete IN while waiting for CMD is usually Status of previous SCSI op, ignore it
       if(ep_addr != p_msc->ep_out) return TUSB_ERROR_NONE;
 
-      TU_ASSERT( event == DCD_XFER_SUCCESS  &&
+      TU_ASSERT( ((uint8_t) event) == DCD_XFER_SUCCESS &&
                  xferred_bytes == sizeof(msc_cbw_t) && p_cbw->signature == MSC_CBW_SIGNATURE, TUSB_ERROR_INVALID_PARA );
 
       p_csw->signature    = MSC_CSW_SIGNATURE;
diff --git a/src/class/msc/msc_device.h b/src/class/msc/msc_device.h
index c1c51255a..c4476f56f 100644
--- a/src/class/msc/msc_device.h
+++ b/src/class/msc/msc_device.h
@@ -180,7 +180,7 @@ void mscd_init(void);
 tusb_error_t mscd_open(uint8_t rhport, tusb_desc_interface_t const * p_interface_desc, uint16_t *p_length);
 bool mscd_control_request(uint8_t rhport, tusb_control_request_t const * p_request);
 bool mscd_control_request_complete (uint8_t rhport, tusb_control_request_t const * p_request);
-tusb_error_t mscd_xfer_cb(uint8_t rhport, uint8_t edpt_addr, tusb_event_t event, uint32_t xferred_bytes);
+tusb_error_t mscd_xfer_cb(uint8_t rhport, uint8_t edpt_addr, xfer_result_t event, uint32_t xferred_bytes);
 void mscd_reset(uint8_t rhport);
 
 #endif
diff --git a/src/class/msc/msc_host.c b/src/class/msc/msc_host.c
index bd3e92de1..baef7ff44 100644
--- a/src/class/msc/msc_host.c
+++ b/src/class/msc/msc_host.c
@@ -397,7 +397,7 @@ tusb_error_t msch_open_subtask(uint8_t dev_addr, tusb_desc_interface_t const *p_
   OSAL_SUBTASK_END
 }
 
-void msch_isr(pipe_handle_t pipe_hdl, tusb_event_t event, uint32_t xferred_bytes)
+void msch_isr(pipe_handle_t pipe_hdl, xfer_result_t event, uint32_t xferred_bytes)
 {
   if ( pipehandle_is_equal(pipe_hdl, msch_data[pipe_hdl.dev_addr-1].bulk_in) )
   {
diff --git a/src/class/msc/msc_host.h b/src/class/msc/msc_host.h
index 6d95cfe34..0afe5c515 100644
--- a/src/class/msc/msc_host.h
+++ b/src/class/msc/msc_host.h
@@ -171,7 +171,7 @@ void tuh_msc_unmounted_cb(uint8_t dev_addr);
 
 /** \brief      Callback function that is invoked when an transferring event occurred
  * \param[in]		dev_addr	Address of device
- * \param[in]   event an value from \ref tusb_event_t
+ * \param[in]   event an value from \ref xfer_result_t
  * \param[in]   xferred_bytes Number of bytes transferred via USB bus
  * \note        event can be one of following
  *              - TUSB_EVENT_XFER_COMPLETE : previously scheduled transfer completes successfully.
@@ -179,7 +179,7 @@ void tuh_msc_unmounted_cb(uint8_t dev_addr);
  *              - TUSB_EVENT_XFER_STALLED : previously scheduled transfer is stalled by device.
  * \note
  */
-void tuh_msc_isr(uint8_t dev_addr, tusb_event_t event, uint32_t xferred_bytes);
+void tuh_msc_isr(uint8_t dev_addr, xfer_result_t event, uint32_t xferred_bytes);
 
 
 //--------------------------------------------------------------------+
@@ -205,7 +205,7 @@ typedef struct {
 
 void         msch_init(void);
 tusb_error_t msch_open_subtask(uint8_t dev_addr, tusb_desc_interface_t const *p_interface_desc, uint16_t *p_length) ATTR_WARN_UNUSED_RESULT;
-void         msch_isr(pipe_handle_t pipe_hdl, tusb_event_t event, uint32_t xferred_bytes);
+void         msch_isr(pipe_handle_t pipe_hdl, xfer_result_t event, uint32_t xferred_bytes);
 void         msch_close(uint8_t dev_addr);
 #endif
 
diff --git a/src/common/tusb_types.h b/src/common/tusb_types.h
index 32632cd90..7b5268d4f 100644
--- a/src/common/tusb_types.h
+++ b/src/common/tusb_types.h
@@ -197,11 +197,10 @@ typedef enum
 
 typedef enum
 {
-  TUSB_EVENT_NONE = 0,
   TUSB_EVENT_XFER_COMPLETE,
   TUSB_EVENT_XFER_ERROR,
   TUSB_EVENT_XFER_STALLED,
-}tusb_event_t;
+}xfer_result_t;
 
 enum
 {
diff --git a/src/device/usbd.c b/src/device/usbd.c
index f39605987..710eba553 100644
--- a/src/device/usbd.c
+++ b/src/device/usbd.c
@@ -92,7 +92,7 @@ typedef struct {
   tusb_error_t (* open           ) (uint8_t rhport, tusb_desc_interface_t const * desc_intf, uint16_t* p_length);
   bool         (* control_request ) (uint8_t rhport, tusb_control_request_t const * request);
   bool (* control_request_complete ) (uint8_t rhport, tusb_control_request_t const * request);
-  tusb_error_t (* xfer_cb        ) (uint8_t rhport, uint8_t ep_addr, tusb_event_t, uint32_t);
+  tusb_error_t (* xfer_cb        ) (uint8_t rhport, uint8_t ep_addr, xfer_result_t, uint32_t);
   void         (* sof            ) (uint8_t rhport);
   void         (* reset          ) (uint8_t);
 } usbd_class_driver_t;
@@ -174,7 +174,7 @@ static bool process_set_config(uint8_t rhport, uint8_t config_number);
 static void const* get_descriptor(tusb_control_request_t const * p_request, uint16_t* desc_len);
 
 void usbd_control_reset (uint8_t rhport);
-bool usbd_control_xfer_cb (uint8_t rhport, uint8_t ep_addr, tusb_event_t event, uint32_t xferred_bytes);
+bool usbd_control_xfer_cb (uint8_t rhport, uint8_t ep_addr, xfer_result_t event, uint32_t xferred_bytes);
 void usbd_control_set_complete_callback( bool (*fp) (uint8_t, tusb_control_request_t const * ) );
 
 //--------------------------------------------------------------------+
diff --git a/src/device/usbd_control.c b/src/device/usbd_control.c
index 33de6d064..31d74edf0 100644
--- a/src/device/usbd_control.c
+++ b/src/device/usbd_control.c
@@ -126,7 +126,7 @@ bool usbd_control_xfer(uint8_t rhport, tusb_control_request_t const * request, v
 }
 
 // callback when a transaction complete on DATA stage of control endpoint
-bool usbd_control_xfer_cb (uint8_t rhport, uint8_t ep_addr, tusb_event_t event, uint32_t xferred_bytes)
+bool usbd_control_xfer_cb (uint8_t rhport, uint8_t ep_addr, xfer_result_t event, uint32_t xferred_bytes)
 {
   if ( _control_state.request.bmRequestType_bit.direction == TUSB_DIR_OUT )
   {
diff --git a/src/host/ehci/ehci.c b/src/host/ehci/ehci.c
index b3d897537..2fc99ffcd 100644
--- a/src/host/ehci/ehci.c
+++ b/src/host/ehci/ehci.c
@@ -638,7 +638,7 @@ static void qhd_xfer_error_isr(ehci_qhd_t * p_qhd)
         qhd_has_xact_error(p_qhd) )
   { // current qhd has error in transaction
     tusb_xfer_type_t const xfer_type = qhd_get_xfer_type(p_qhd);
-    tusb_event_t error_event;
+    xfer_result_t error_event;
 
     // no error bits are set, endpoint is halted due to STALL
     error_event = qhd_has_xact_error(p_qhd) ? TUSB_EVENT_XFER_ERROR : TUSB_EVENT_XFER_STALLED;
diff --git a/src/host/hub.c b/src/host/hub.c
index e4c08c9d1..9635bcc0b 100644
--- a/src/host/hub.c
+++ b/src/host/hub.c
@@ -209,7 +209,7 @@ tusb_error_t hub_open_subtask(uint8_t dev_addr, tusb_desc_interface_t const *p_i
 }
 
 // is the response of interrupt endpoint polling
-void hub_isr(pipe_handle_t pipe_hdl, tusb_event_t event, uint32_t xferred_bytes)
+void hub_isr(pipe_handle_t pipe_hdl, xfer_result_t event, uint32_t xferred_bytes)
 {
   (void) xferred_bytes; // TODO can be more than 1 for hub with lots of ports
 
diff --git a/src/host/hub.h b/src/host/hub.h
index 67c02f2e3..9376a2698 100644
--- a/src/host/hub.h
+++ b/src/host/hub.h
@@ -196,7 +196,7 @@ tusb_error_t hub_status_pipe_queue(uint8_t dev_addr);
 
 void         hub_init(void);
 tusb_error_t hub_open_subtask(uint8_t dev_addr, tusb_desc_interface_t const *p_interface_desc, uint16_t *p_length) ATTR_WARN_UNUSED_RESULT;
-void         hub_isr(pipe_handle_t pipe_hdl, tusb_event_t event, uint32_t xferred_bytes);
+void         hub_isr(pipe_handle_t pipe_hdl, xfer_result_t event, uint32_t xferred_bytes);
 void         hub_close(uint8_t dev_addr);
 
 #endif
diff --git a/src/host/ohci/ohci.c b/src/host/ohci/ohci.c
index f058f8348..58738a236 100644
--- a/src/host/ohci/ohci.c
+++ b/src/host/ohci/ohci.c
@@ -617,7 +617,7 @@ static void done_queue_isr(uint8_t hostid)
     // TODO check if td_head is iso td
     //------------- Non ISO transfer -------------//
     ohci_gtd_t * const p_qtd = (ohci_gtd_t *) td_head;
-    tusb_event_t const event = (p_qtd->condition_code == OHCI_CCODE_NO_ERROR) ? TUSB_EVENT_XFER_COMPLETE :
+    xfer_result_t const event = (p_qtd->condition_code == OHCI_CCODE_NO_ERROR) ? TUSB_EVENT_XFER_COMPLETE :
                                (p_qtd->condition_code == OHCI_CCODE_STALL) ? TUSB_EVENT_XFER_STALLED : TUSB_EVENT_XFER_ERROR;
 
     p_qtd->used = 0; // free TD
diff --git a/src/host/usbh.c b/src/host/usbh.c
index 196a45ee7..ed21bf3da 100644
--- a/src/host/usbh.c
+++ b/src/host/usbh.c
@@ -256,7 +256,7 @@ static inline uint8_t std_class_code_to_index(uint8_t std_class_code)
 // USBH-HCD ISR/Callback API
 //--------------------------------------------------------------------+
 // interrupt caused by a TD (with IOC=1) in pipe of class class_code
-void usbh_xfer_isr(pipe_handle_t pipe_hdl, uint8_t class_code, tusb_event_t event, uint32_t xferred_bytes)
+void usbh_xfer_isr(pipe_handle_t pipe_hdl, uint8_t class_code, xfer_result_t event, uint32_t xferred_bytes)
 {
   uint8_t class_index = std_class_code_to_index(class_code);
   if (TUSB_XFER_CONTROL == pipe_hdl.xfer_type)
diff --git a/src/host/usbh.h b/src/host/usbh.h
index 5aaeb4186..22fdef162 100644
--- a/src/host/usbh.h
+++ b/src/host/usbh.h
@@ -66,7 +66,7 @@ typedef enum tusb_interface_status_{
 typedef struct {
   void (* const init) (void);
   tusb_error_t (* const open_subtask)(uint8_t, tusb_desc_interface_t const *, uint16_t*);
-  void (* const isr) (pipe_handle_t, tusb_event_t, uint32_t);
+  void (* const isr) (pipe_handle_t, xfer_result_t, uint32_t);
   void (* const close) (uint8_t);
 } host_class_driver_t;
 //--------------------------------------------------------------------+
diff --git a/src/host/usbh_hcd.h b/src/host/usbh_hcd.h
index 1c2c4ad0b..f6b72273a 100644
--- a/src/host/usbh_hcd.h
+++ b/src/host/usbh_hcd.h
@@ -101,7 +101,7 @@ extern usbh_device_info_t usbh_devices[CFG_TUSB_HOST_DEVICE_MAX+1]; // including
 //--------------------------------------------------------------------+
 // callback from HCD ISR
 //--------------------------------------------------------------------+
-void usbh_xfer_isr(pipe_handle_t pipe_hdl, uint8_t class_code, tusb_event_t event, uint32_t xferred_bytes);
+void usbh_xfer_isr(pipe_handle_t pipe_hdl, uint8_t class_code, xfer_result_t event, uint32_t xferred_bytes);
 void usbh_hcd_rhport_plugged_isr(uint8_t hostid);
 void usbh_hcd_rhport_unplugged_isr(uint8_t hostid);
 
diff --git a/tests/lpc18xx_43xx/test/host/cdc/cdc_callback.h b/tests/lpc18xx_43xx/test/host/cdc/cdc_callback.h
index b1aea64b0..1eb608b91 100644
--- a/tests/lpc18xx_43xx/test/host/cdc/cdc_callback.h
+++ b/tests/lpc18xx_43xx/test/host/cdc/cdc_callback.h
@@ -55,7 +55,7 @@
 
 void tusbh_cdc_mounted_cb(uint8_t dev_addr);
 void tusbh_cdc_unmounted_cb(uint8_t dev_addr);
-void tusbh_cdc_xfer_isr(uint8_t dev_addr, tusb_event_t event, cdc_pipeid_t pipe_id, uint32_t xferred_bytes);
+void tusbh_cdc_xfer_isr(uint8_t dev_addr, xfer_result_t event, cdc_pipeid_t pipe_id, uint32_t xferred_bytes);
 
 void tusbh_cdc_rndis_mounted_cb(uint8_t dev_addr);
 void tusbh_cdc_rndis_unmounted_isr(uint8_t dev_addr);
diff --git a/tests/lpc18xx_43xx/test/host/hid/hidh_callback.h b/tests/lpc18xx_43xx/test/host/hid/hidh_callback.h
index 4b76bd3cd..b0945c1d1 100644
--- a/tests/lpc18xx_43xx/test/host/hid/hidh_callback.h
+++ b/tests/lpc18xx_43xx/test/host/hid/hidh_callback.h
@@ -59,11 +59,11 @@
 #include "common/common.h"
 
 //------------- hidh -------------//
-void tusbh_hid_keyboard_isr(uint8_t dev_addr, tusb_event_t event);
+void tusbh_hid_keyboard_isr(uint8_t dev_addr, xfer_result_t event);
 void tusbh_hid_keyboard_mounted_cb(uint8_t dev_addr);
 void tusbh_hid_keyboard_unmounted_cb(uint8_t dev_addr);
 
-void tusbh_hid_mouse_isr(uint8_t dev_addr, tusb_event_t event);
+void tusbh_hid_mouse_isr(uint8_t dev_addr, xfer_result_t event);
 void tusbh_hid_mouse_mounted_cb(uint8_t dev_addr);
 void tusbh_hid_mouse_unmounted_cb(uint8_t dev_addr);
 
diff --git a/tests/lpc18xx_43xx/test/host/msc/msch_callback.h b/tests/lpc18xx_43xx/test/host/msc/msch_callback.h
index 26b301a00..275245bec 100644
--- a/tests/lpc18xx_43xx/test/host/msc/msch_callback.h
+++ b/tests/lpc18xx_43xx/test/host/msc/msch_callback.h
@@ -54,7 +54,7 @@
 
 void tusbh_msc_mounted_cb(uint8_t dev_addr);
 void tusbh_msc_unmounted_cb(uint8_t dev_addr);
-void tusbh_msc_isr(uint8_t dev_addr, tusb_event_t event, uint32_t xferred_bytes);
+void tusbh_msc_isr(uint8_t dev_addr, xfer_result_t event, uint32_t xferred_bytes);
 
 
 #ifdef __cplusplus