--- Middlewares/ST/STM32_USB_Device_Library/Core/Inc/usbd_def.h	(date 1511202099000)
+++ Middlewares/ST/STM32_USB_Device_Library/Core/Inc/usbd_def.h	(revision )
@@ -99,6 +99,7 @@
 #define  USB_DESC_TYPE_ENDPOINT                            5
 #define  USB_DESC_TYPE_DEVICE_QUALIFIER                    6
 #define  USB_DESC_TYPE_OTHER_SPEED_CONFIGURATION           7
+#define  USB_DESC_TYPE_IFACE_ASSOCIATION                   11
 #define  USB_DESC_TYPE_BOS                                 0x0F
 
 #define USB_CONFIG_REMOTE_WAKEUP                           2
@@ -147,7 +148,7 @@
 
 typedef  struct  usb_setup_req 
 {
-    
+
     uint8_t   bmRequest;                      
     uint8_t   bRequest;                           
     uint16_t  wValue;                             
@@ -230,7 +231,7 @@
   uint32_t                dev_config_status; 
   USBD_SpeedTypeDef       dev_speed; 
   USBD_EndpointTypeDef    ep_in[15];
-  USBD_EndpointTypeDef    ep_out[15];  
+  USBD_EndpointTypeDef    ep_out[15];
   uint32_t                ep0_state;  
   uint32_t                ep0_data_len;     
   uint8_t                 dev_state;
@@ -242,10 +243,14 @@
 
   USBD_SetupReqTypedef    request;
   USBD_DescriptorsTypeDef *pDesc;
-  USBD_ClassTypeDef       *pClass;
-  void                    *pClassData;  
-  void                    *pUserData;    
-  void                    *pData;    
+  USBD_ClassTypeDef       *pClass; // the composite class
+  void                    *pClassData;
+  void                    *pUserData;
+  void                    *pClassData2; // used for secondary class
+  void                    *pUserData2; // used for secondary class
+  void                    *pClassData3; // used for tertiary class
+  void                    *pUserData3; // used for tertiary class
+  void                    *pData; // this is a pointer to the low level registers struct
 } USBD_HandleTypeDef;
 
 /**
@@ -262,8 +267,14 @@
 
 #define LOBYTE(x)  ((uint8_t)(x & 0x00FF))
 #define HIBYTE(x)  ((uint8_t)((x & 0xFF00) >>8))
+
+#ifndef MIN
 #define MIN(a, b)  (((a) < (b)) ? (a) : (b))
+#endif
+
+#ifndef MAX
 #define MAX(a, b)  (((a) > (b)) ? (a) : (b))
+#endif
 
 
 #if  defined ( __GNUC__ )