1e41f4b71Sopenharmony_ci# UsbInterfaceDescriptor 2e41f4b71Sopenharmony_ci 3e41f4b71Sopenharmony_ci 4e41f4b71Sopenharmony_ci## Overview 5e41f4b71Sopenharmony_ci 6e41f4b71Sopenharmony_ciDefines standard interface descriptors, which correspond to **Standard Interface Descriptor** in the USB protocol. 7e41f4b71Sopenharmony_ci 8e41f4b71Sopenharmony_ci**Since** 9e41f4b71Sopenharmony_ci 10e41f4b71Sopenharmony_ci10 11e41f4b71Sopenharmony_ci 12e41f4b71Sopenharmony_ci**Related Modules** 13e41f4b71Sopenharmony_ci 14e41f4b71Sopenharmony_ci[USB DDK](_usb_ddk.md) 15e41f4b71Sopenharmony_ci 16e41f4b71Sopenharmony_ci 17e41f4b71Sopenharmony_ci## Summary 18e41f4b71Sopenharmony_ci 19e41f4b71Sopenharmony_ci 20e41f4b71Sopenharmony_ci### Member Variables 21e41f4b71Sopenharmony_ci 22e41f4b71Sopenharmony_ci| Name| Description| 23e41f4b71Sopenharmony_ci| -------- | -------- | 24e41f4b71Sopenharmony_ci| [bLength](#blength) | Size of the descriptor, in bytes.| 25e41f4b71Sopenharmony_ci| [bDescriptorType](#bdescriptortype) | Descriptor type.| 26e41f4b71Sopenharmony_ci| [bInterfaceNumber](#binterfacenumber) | Interface ID.| 27e41f4b71Sopenharmony_ci| [bAlternateSetting](#balternatesetting) | Value used to select the alternate setting of the interface.| 28e41f4b71Sopenharmony_ci| [bNumEndpoints](#bnumendpoints) | Number of endpoints (excluding endpoint 0) used by the interface.| 29e41f4b71Sopenharmony_ci| [bInterfaceClass](#binterfaceclass) | Interface class code allocated by the USB-IF.| 30e41f4b71Sopenharmony_ci| [bInterfaceSubClass](#binterfacesubclass) | Device subclass code allocated by USB-IF. The value is limited by that of [bInterfaceClass](#binterfaceclass).| 31e41f4b71Sopenharmony_ci| [bInterfaceProtocol](#binterfaceprotocol) | Protocol code allocated by USB-IF. The value is limited by that of [bInterfaceClass](#binterfaceclass) and [bInterfaceSubClass](#binterfacesubclass).| 32e41f4b71Sopenharmony_ci| [iInterface](#iinterface) | Index of the string descriptor that describes the interface.| 33e41f4b71Sopenharmony_ci 34e41f4b71Sopenharmony_ci 35e41f4b71Sopenharmony_ci## Member Variable Description 36e41f4b71Sopenharmony_ci 37e41f4b71Sopenharmony_ci 38e41f4b71Sopenharmony_ci### bAlternateSetting 39e41f4b71Sopenharmony_ci 40e41f4b71Sopenharmony_ci 41e41f4b71Sopenharmony_ci``` 42e41f4b71Sopenharmony_ciuint8_t UsbInterfaceDescriptor::bAlternateSetting 43e41f4b71Sopenharmony_ci``` 44e41f4b71Sopenharmony_ci 45e41f4b71Sopenharmony_ci**Description** 46e41f4b71Sopenharmony_ci 47e41f4b71Sopenharmony_ciValue used to select the alternate setting of the interface. 48e41f4b71Sopenharmony_ci 49e41f4b71Sopenharmony_ci 50e41f4b71Sopenharmony_ci### bDescriptorType 51e41f4b71Sopenharmony_ci 52e41f4b71Sopenharmony_ci 53e41f4b71Sopenharmony_ci``` 54e41f4b71Sopenharmony_ciuint8_t UsbInterfaceDescriptor::bDescriptorType 55e41f4b71Sopenharmony_ci``` 56e41f4b71Sopenharmony_ci 57e41f4b71Sopenharmony_ci**Description** 58e41f4b71Sopenharmony_ci 59e41f4b71Sopenharmony_ciDescriptor type. 60e41f4b71Sopenharmony_ci 61e41f4b71Sopenharmony_ci 62e41f4b71Sopenharmony_ci### bInterfaceClass 63e41f4b71Sopenharmony_ci 64e41f4b71Sopenharmony_ci 65e41f4b71Sopenharmony_ci``` 66e41f4b71Sopenharmony_ciuint8_t UsbInterfaceDescriptor::bInterfaceClass 67e41f4b71Sopenharmony_ci``` 68e41f4b71Sopenharmony_ci 69e41f4b71Sopenharmony_ci**Description** 70e41f4b71Sopenharmony_ci 71e41f4b71Sopenharmony_ciInterface class code allocated by the USB-IF. 72e41f4b71Sopenharmony_ci 73e41f4b71Sopenharmony_ci 74e41f4b71Sopenharmony_ci### bInterfaceNumber 75e41f4b71Sopenharmony_ci 76e41f4b71Sopenharmony_ci 77e41f4b71Sopenharmony_ci``` 78e41f4b71Sopenharmony_ciuint8_t UsbInterfaceDescriptor::bInterfaceNumber 79e41f4b71Sopenharmony_ci``` 80e41f4b71Sopenharmony_ci 81e41f4b71Sopenharmony_ci**Description** 82e41f4b71Sopenharmony_ci 83e41f4b71Sopenharmony_ciInterface ID. 84e41f4b71Sopenharmony_ci 85e41f4b71Sopenharmony_ci 86e41f4b71Sopenharmony_ci### bInterfaceProtocol 87e41f4b71Sopenharmony_ci 88e41f4b71Sopenharmony_ci 89e41f4b71Sopenharmony_ci``` 90e41f4b71Sopenharmony_ciuint8_t UsbInterfaceDescriptor::bInterfaceProtocol 91e41f4b71Sopenharmony_ci``` 92e41f4b71Sopenharmony_ci 93e41f4b71Sopenharmony_ci**Description** 94e41f4b71Sopenharmony_ci 95e41f4b71Sopenharmony_ciProtocol code allocated by USB-IF. The value is limited by that of [bInterfaceClass](#binterfaceclass) and [bInterfaceSubClass](#binterfacesubclass). 96e41f4b71Sopenharmony_ci 97e41f4b71Sopenharmony_ci 98e41f4b71Sopenharmony_ci### bInterfaceSubClass 99e41f4b71Sopenharmony_ci 100e41f4b71Sopenharmony_ci 101e41f4b71Sopenharmony_ci``` 102e41f4b71Sopenharmony_ciuint8_t UsbInterfaceDescriptor::bInterfaceSubClass 103e41f4b71Sopenharmony_ci``` 104e41f4b71Sopenharmony_ci 105e41f4b71Sopenharmony_ci**Description** 106e41f4b71Sopenharmony_ci 107e41f4b71Sopenharmony_ciDevice subclass code allocated by USB-IF. The value is limited by that of [bInterfaceClass](#binterfaceclass). 108e41f4b71Sopenharmony_ci 109e41f4b71Sopenharmony_ci 110e41f4b71Sopenharmony_ci### bLength 111e41f4b71Sopenharmony_ci 112e41f4b71Sopenharmony_ci 113e41f4b71Sopenharmony_ci``` 114e41f4b71Sopenharmony_ciuint8_t UsbInterfaceDescriptor::bLength 115e41f4b71Sopenharmony_ci``` 116e41f4b71Sopenharmony_ci 117e41f4b71Sopenharmony_ci**Description** 118e41f4b71Sopenharmony_ci 119e41f4b71Sopenharmony_ciSize of the descriptor, in bytes. 120e41f4b71Sopenharmony_ci 121e41f4b71Sopenharmony_ci 122e41f4b71Sopenharmony_ci### bNumEndpoints 123e41f4b71Sopenharmony_ci 124e41f4b71Sopenharmony_ci 125e41f4b71Sopenharmony_ci``` 126e41f4b71Sopenharmony_ciuint8_t UsbInterfaceDescriptor::bNumEndpoints 127e41f4b71Sopenharmony_ci``` 128e41f4b71Sopenharmony_ci 129e41f4b71Sopenharmony_ci**Description** 130e41f4b71Sopenharmony_ci 131e41f4b71Sopenharmony_ciNumber of endpoints (excluding endpoint 0) used by the interface. 132e41f4b71Sopenharmony_ci 133e41f4b71Sopenharmony_ci 134e41f4b71Sopenharmony_ci### iInterface 135e41f4b71Sopenharmony_ci 136e41f4b71Sopenharmony_ci 137e41f4b71Sopenharmony_ci``` 138e41f4b71Sopenharmony_ciuint8_t UsbInterfaceDescriptor::iInterface 139e41f4b71Sopenharmony_ci``` 140e41f4b71Sopenharmony_ci 141e41f4b71Sopenharmony_ci**Description** 142e41f4b71Sopenharmony_ci 143e41f4b71Sopenharmony_ciIndex of the string descriptor that describes the interface. 144