diff --git a/lib/main/STM32_USB_Device_Library/Class/cdc/inc/usbd_cdc_core.h b/lib/main/STM32_USB_Device_Library/Class/cdc/inc/usbd_cdc_core.h
index 7b63e90a69..b9afa7423d 100644
--- a/lib/main/STM32_USB_Device_Library/Class/cdc/inc/usbd_cdc_core.h
+++ b/lib/main/STM32_USB_Device_Library/Class/cdc/inc/usbd_cdc_core.h
@@ -95,7 +95,7 @@ typedef struct _CDC_IF_PROP
   uint16_t (*pIf_Init)     (void);   
   uint16_t (*pIf_DeInit)   (void);   
   uint16_t (*pIf_Ctrl)     (uint32_t Cmd, uint8_t* Buf, uint32_t Len);
-  uint16_t (*pIf_DataTx)   (void);
+  uint16_t (*pIf_DataTx)   (uint8_t* Buf, uint32_t Len);
   uint16_t (*pIf_DataRx)   (uint8_t* Buf, uint32_t Len);
 }
 CDC_IF_Prop_TypeDef;