1# UsbInterfaceDescriptor 2<!--Kit: Driver Development Kit--> 3<!--Subsystem: Driver--> 4<!--Owner: @lixinsheng2--> 5<!--Designer: @w00373942--> 6<!--Tester: @dong-dongzhen--> 7<!--Adviser: @w_Machine_cc--> 8 9## Overview 10 11Defines standard interface descriptors, which correspond to **Standard Interface Descriptor** in the USB protocol. 12 13**Since**: 10 14 15**Related module**: [UsbDDK](capi-usbddk.md) 16 17**Header file:** [usb_ddk_types.h](capi-usb-ddk-types-h.md) 18 19## Summary 20 21### Member Variables 22 23| Name| Description| 24| -- | -- | 25| uint8_t bLength | Size of the descriptor, in bytes.| 26| uint8_t bDescriptorType | Descriptor type.| 27| uint8_t bInterfaceNumber | Interface ID.| 28| uint8_t bAlternateSetting | Value used to select the alternate setting of the interface.| 29| uint8_t bNumEndpoints | Number of endpoints (excluding endpoint 0) used by the interface.| 30| uint8_t bInterfaceClass | Interface class code allocated by the USB-IF.| 31| uint8_t bInterfaceSubClass | Device subclass code allocated by USB-IF. The value is limited by that of {@link bInterfaceClass}.| 32| uint8_t bInterfaceProtocol | Protocol code allocated by USB-IF. The value is limited by that of {@link bInterfaceClass} and {@link bInterfaceSubClass}.| 33| uint8_t iInterface | Index of the string descriptor that describes the interface.| 34