1e41f4b71Sopenharmony_ci# usb_ddk_api.h 2e41f4b71Sopenharmony_ci 3e41f4b71Sopenharmony_ci 4e41f4b71Sopenharmony_ci## Overview 5e41f4b71Sopenharmony_ci 6e41f4b71Sopenharmony_ciDeclares the USB DDK APIs used by the USB host to access USB devices. 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### Functions 21e41f4b71Sopenharmony_ci 22e41f4b71Sopenharmony_ci| Name| Description| 23e41f4b71Sopenharmony_ci| -------- | -------- | 24e41f4b71Sopenharmony_ci| [OH_Usb_Init](_usb_ddk.md#oh_usb_init) (void) | Initializes the DDK.| 25e41f4b71Sopenharmony_ci| [OH_Usb_Release](_usb_ddk.md#oh_usb_release) (void) | Releases the USB DDK.| 26e41f4b71Sopenharmony_ci| [OH_Usb_GetDeviceDescriptor](_usb_ddk.md#oh_usb_getdevicedescriptor) (uint64_t deviceId, struct [UsbDeviceDescriptor](_usb_device_descriptor.md) \*desc) | Obtains the device descriptor.| 27e41f4b71Sopenharmony_ci| [OH_Usb_GetConfigDescriptor](_usb_ddk.md#oh_usb_getconfigdescriptor) (uint64_t deviceId, uint8_t configIndex, struct [UsbDdkConfigDescriptor](_usb_ddk_config_descriptor.md) \*\*const config) | Obtains the configuration descriptor. To avoid memory leakage, use [OH_Usb_FreeConfigDescriptor()](_usb_ddk.md#oh_usb_freeconfigdescriptor) to release a descriptor after use.| 28e41f4b71Sopenharmony_ci| [OH_Usb_FreeConfigDescriptor](_usb_ddk.md#oh_usb_freeconfigdescriptor) (const struct [UsbDdkConfigDescriptor](_usb_ddk_config_descriptor.md) \*const config) | Releases the configuration descriptor. To avoid memory leakage, release a descriptor after use.| 29e41f4b71Sopenharmony_ci| [OH_Usb_ClaimInterface](_usb_ddk.md#oh_usb_claiminterface) (uint64_t deviceId, uint8_t interfaceIndex, uint64_t \*[interfaceHandle](usb__ddk__types_8h.md#interfacehandle)) | Declares a USB interface.| 30e41f4b71Sopenharmony_ci| [OH_Usb_ReleaseInterface](_usb_ddk.md#oh_usb_releaseinterface) (uint64_t [interfaceHandle](usb__ddk__types_8h.md#interfacehandle)) | Releases a USB interface.| 31e41f4b71Sopenharmony_ci| [OH_Usb_SelectInterfaceSetting](_usb_ddk.md#oh_usb_selectinterfacesetting) (uint64_t [interfaceHandle](usb__ddk__types_8h.md#interfacehandle), uint8_t settingIndex) | Activates the alternate setting of a USB interface.| 32e41f4b71Sopenharmony_ci| [OH_Usb_GetCurrentInterfaceSetting](_usb_ddk.md#oh_usb_getcurrentinterfacesetting) (uint64_t [interfaceHandle](usb__ddk__types_8h.md#interfacehandle), uint8_t \*settingIndex) | Obtains the activated alternate setting of a USB interface.| 33e41f4b71Sopenharmony_ci| [OH_Usb_SendControlReadRequest](_usb_ddk.md#oh_usb_sendcontrolreadrequest) (uint64_t [interfaceHandle](usb__ddk__types_8h.md#interfacehandle), const struct [UsbControlRequestSetup](_usb_control_request_setup.md) \*setup, uint32_t [timeout](usb__ddk__types_8h.md#timeout), uint8_t \*data, uint32_t \*dataLen) | Sends a control read transfer request. This API works in a synchronous manner.| 34e41f4b71Sopenharmony_ci| [OH_Usb_SendControlWriteRequest](_usb_ddk.md#oh_usb_sendcontrolwriterequest) (uint64_t [interfaceHandle](usb__ddk__types_8h.md#interfacehandle), const struct [UsbControlRequestSetup](_usb_control_request_setup.md) \*setup, uint32_t [timeout](usb__ddk__types_8h.md#timeout), const uint8_t \*data, uint32_t dataLen) | Sends a control write transfer request. This API works in a synchronous manner.| 35e41f4b71Sopenharmony_ci| [OH_Usb_SendPipeRequest](_usb_ddk.md#oh_usb_sendpiperequest) (const struct [UsbRequestPipe](_usb_request_pipe.md) \*pipe, [UsbDeviceMemMap](_usb_device_mem_map.md) \*devMmap) | Sends a pipe request. This API works in a synchronous manner. It applies to interrupt transfer and bulk transfer.| 36e41f4b71Sopenharmony_ci| [OH_Usb_SendPipeRequestWithAshmem](_usb_ddk.md#oh_usb_sendpiperequestwithashmem) (const struct [UsbRequestPipe](_usb_request_pipe.md) \*pipe, [DDK_Ashmem](_ddk_ashmem.md) \*ashmem) | Sends a pipe request for the shared memory. This API returns the result synchronously. It applies to interrupt transfer and bulk transfer.| 37e41f4b71Sopenharmony_ci| [OH_Usb_CreateDeviceMemMap](_usb_ddk.md#oh_usb_createdevicememmap) (uint64_t deviceId, size_t size, [UsbDeviceMemMap](_usb_device_mem_map.md) \*\*devMmap) | Creates a buffer. To avoid memory leakage, use [OH_Usb_DestroyDeviceMemMap()](_usb_ddk.md#oh_usb_destroydevicememmap) to destroy a buffer after use.| 38e41f4b71Sopenharmony_ci| [OH_Usb_DestroyDeviceMemMap](_usb_ddk.md#oh_usb_destroydevicememmap) ([UsbDeviceMemMap](_usb_device_mem_map.md) \*devMmap) | Destroys a buffer. To avoid resource leakage, destroy a buffer in time after use.| 39