diff --git a/tests/project.yml b/tests/project.yml
index be644f147..c33818a15 100644
--- a/tests/project.yml
+++ b/tests/project.yml
@@ -48,6 +48,7 @@
     - MCU=MCU_LPC43XX
     - CORE_M4
     - __CODE_RED
+    - _TINY_USB_SOURCE_FILE_
   :test_preprocess:
     - *common_defines
     - _TEST_
diff --git a/tests/test/host/test_hid_host_keyboard.c b/tests/test/host/test_hid_host_keyboard.c
index 39e4303ac..aab1636fe 100644
--- a/tests/test/host/test_hid_host_keyboard.c
+++ b/tests/test/host/test_hid_host_keyboard.c
@@ -90,7 +90,7 @@ void tearDown(void)
 }
 
 //--------------------------------------------------------------------+
-// keyboard_install, keyboard_no_instances
+// keyboard_install, keyboard_no_instances, keybaord_init
 //--------------------------------------------------------------------+
 void test_keyboard_no_instances_invalid_para(void)
 {
@@ -107,6 +107,16 @@ void test_keyboard_install_ok(void)
   TEST_ASSERT_EQUAL(1, tusbh_hid_keyboard_no_instances(device_hdl));
 }
 
+void test_keyboard_init(void)
+{
+  class_hid_keyboard_info_t keyboard_info_zero[TUSB_CFG_HOST_DEVICE_MAX];
+  memset(&keyboard_info_zero, 0, sizeof(class_hid_keyboard_info_t)*TUSB_CFG_HOST_DEVICE_MAX);
+
+  class_hid_keyboard_init();
+
+  TEST_ASSERT_EQUAL_MEMORY(keyboard_info_zero, keyboard_info_pool, sizeof(class_hid_keyboard_info_t)*TUSB_CFG_HOST_DEVICE_MAX);
+}
+
 //--------------------------------------------------------------------+
 // keyboard_get
 //--------------------------------------------------------------------+
diff --git a/tinyusb/class/hid_host.c b/tinyusb/class/hid_host.c
index d71aa8d52..3853f2538 100644
--- a/tinyusb/class/hid_host.c
+++ b/tinyusb/class/hid_host.c
@@ -39,6 +39,8 @@
 
 #if defined TUSB_CFG_HOST && defined DEVICE_CLASS_HID
 
+#define _TINY_USB_SOURCE_FILE_
+
 //--------------------------------------------------------------------+
 // INCLUDE
 //--------------------------------------------------------------------+
@@ -55,7 +57,7 @@ class_hid_keyboard_info_t keyboard_info_pool[TUSB_CFG_HOST_DEVICE_MAX];
 
 
 //--------------------------------------------------------------------+
-// IMPLEMENTATION
+// PUBLIC API
 //--------------------------------------------------------------------+
 tusb_error_t tusbh_hid_keyboard_get(tusb_handle_device_t const device_hdl, uint8_t instance_num, tusb_keyboard_report_t * const report)
 {
@@ -83,6 +85,14 @@ uint8_t tusbh_hid_keyboard_no_instances(tusb_handle_device_t const device_hdl)
   return keyboard_info_pool[device_hdl].instance_count;
 }
 
+//--------------------------------------------------------------------+
+// CLASS-USBD API
+//--------------------------------------------------------------------+
+tusb_error_t class_hid_keyboard_init(void)
+{
+  memset(&keyboard_info_pool, 0, sizeof(class_hid_keyboard_info_t)*TUSB_CFG_HOST_DEVICE_MAX);
+}
+
 tusb_error_t class_hid_keyboard_install(uint8_t const dev_addr, uint8_t const *descriptor)
 {
   keyboard_info_pool[0].instance_count++;
@@ -90,6 +100,4 @@ tusb_error_t class_hid_keyboard_install(uint8_t const dev_addr, uint8_t const *d
   return TUSB_ERROR_NONE;
 }
 
-
 #endif
-
diff --git a/tinyusb/class/hid_host.h b/tinyusb/class/hid_host.h
index 0dab9f08b..a34a813d9 100644
--- a/tinyusb/class/hid_host.h
+++ b/tinyusb/class/hid_host.h
@@ -67,19 +67,24 @@ tusb_error_t tusbh_hid_keyboard_get(tusb_handle_device_t const handle, uint8_t i
 //--------------------------------------------------------------------+
 // INTERNAL API
 //--------------------------------------------------------------------+
+#ifdef _TINY_USB_SOURCE_FILE_
+
 typedef struct {
   pipe_handle_t pipe_in;
   uint8_t report_size;
   uint8_t buffer[TUSB_CFG_HOST_HID_KEYBOARD_ENDPOINT_SIZE];
 }keyboard_interface_t;
 
-typedef struct { // TODO internal structure
+typedef struct {
   uint8_t instance_count;
   keyboard_interface_t instance[TUSB_CFG_HOST_HID_KEYBOARD_NO_INSTANCES_PER_DEVICE];
 } class_hid_keyboard_info_t;
 
+tusb_error_t class_hid_keyboard_init(void);
 tusb_error_t class_hid_keyboard_install(uint8_t const dev_addr, uint8_t const *descriptor);
 
+#endif
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/tinyusb/host/usbd_host.h b/tinyusb/host/usbd_host.h
index 26e0b2ccf..8fb76a5a9 100644
--- a/tinyusb/host/usbd_host.h
+++ b/tinyusb/host/usbd_host.h
@@ -55,8 +55,14 @@
  extern "C" {
 #endif
 
+//--------------------------------------------------------------------+
+// INCLUDE
+//--------------------------------------------------------------------+
 #include "hcd.h"
 
+//--------------------------------------------------------------------+
+// MACRO CONSTANT TYPEDEF
+//--------------------------------------------------------------------+
 enum {
   TUSB_FLAGS_CLASS_UNSPECIFIED          = BIT_(0)    , ///< 0
   TUSB_FLAGS_CLASS_AUDIO                = BIT_(1)    , ///< 1
@@ -116,10 +122,11 @@ typedef enum {
   PIPE_STATUS_BUSY,
   PIPE_STATUS_COMPLETE
 } pipe_status_t;
-//--------------------------------------------------------------------+
-// Structures & Types
-//--------------------------------------------------------------------+
+
 typedef uint32_t tusb_handle_device_t;
+//--------------------------------------------------------------------+
+// INTERNAL OBJECT & FUNCTION DECLARATION
+//--------------------------------------------------------------------+
 
 //--------------------------------------------------------------------+
 // APPLICATION API
@@ -129,13 +136,16 @@ void         tusbh_device_mounted_cb (tusb_error_t const error, tusb_handle_devi
 tusb_error_t tusbh_configuration_set     (tusb_handle_device_t const device_hdl, uint8_t const configure_number);
 
 
-// TODO hiding from application include
 //--------------------------------------------------------------------+
-// CLASS API
+// CLASS-USBD API
 //--------------------------------------------------------------------+
+#ifdef _TINY_USB_SOURCE_FILE_
+
 bool          usbh_device_is_plugged(tusb_handle_device_t const device_hdl);
 pipe_status_t usbh_pipe_status_get(pipe_handle_t pipe_hdl);
 
+#endif
+
 #ifdef __cplusplus
  }
 #endif