USB
This module provides USB device management functions, including USB device list query, bulk data transfer, control transfer, and permission control.
NOTE
The initial APIs of this module are supported since API version 8. Newly added APIs will be marked with a superscript to indicate their earliest API version.
Modules to Import
import usb from "@ohos.usb";
usb.getDevices
getDevices(): Array<Readonly<USBDevice>>
Obtains the USB device list.
System capability: SystemCapability.USB.USBManager
- Return value
Type | Description |
---|---|
Array<Readonly<USBDevice>> | Device information list. |
- Example
let devicesList = usb.getDevices(); console.log(`devicesList = ${JSON.stringify(devicesList)}`); // devicesList is a list of USB devices. // A simple example of devicesList is provided as follows: [ { name: "1-1", serial: "", manufacturerName: "", productName: "", version: "", vendorId: 7531, productId: 2, clazz: 9, subclass: 0, protocol: 1, devAddress: 1, busNum: 1, configs: [ { id: 1, attributes: 224, isRemoteWakeup: true, isSelfPowered: true, maxPower: 0, name: "1-1", interfaces: [ { id: 0, protocol: 0, clazz: 9, subclass: 0, alternateSetting: 0, name: "1-1", endpoints: [ { address: 129, attributes: 3, interval: 12, maxPacketSize: 4, direction: 128, number: 1, type: 3, interfaceId: 0, }, ], }, ], }, ], }, ]
usb.connectDevice
connectDevice(device: USBDevice): Readonly<USBDevicePipe>
Connects to a USB device.
Before you do this, call usb.getDevices to obtain the USB device list, and then call usb.requestRight to request the device access permission.
System capability: SystemCapability.USB.USBManager
- Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
device | USBDevice | Yes | USB device information. |
- Return value
Type | Description |
---|---|
Readonly<USBDevicePipe> | USB device pipe for data transfer. |
- Example
let devicepipe= usb.connectDevice(device); console.log(`devicepipe = ${JSON.stringify(devicepipe)}`);
usb.hasRight
hasRight(deviceName: string): boolean
Checks whether the application has the permission to access the device.
System capability: SystemCapability.USB.USBManager
- Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
deviceName | string | Yes | Device name. |
- Return value
Type | Description |
---|---|
boolean | Returns true if the application has the permission to access the device; returns false otherwise. |
- Example
let devicesName="1-1"; let bool = usb.hasRight(devicesName); console.log(bool);
usb.requestRight
requestRight(deviceName: string): Promise<boolean>
Requests the temporary permission for the application to access the USB device.
System capability: SystemCapability.USB.USBManager
- Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
deviceName | string | Yes | Device name. |
- Return value
Type | Description |
---|---|
Promise<boolean> | Returns true if the temporary device access permissions are granted; returns false otherwise. |
- Example
let devicesName="1-1"; usb.requestRight(devicesName).then((ret) => { console.log(`requestRight = ${JSON.stringify(ret)}`); });
usb.claimInterface
claimInterface(pipe: USBDevicePipe, iface: USBInterface, force?: boolean): number
Claims a USB interface.
Before you do this, call usb.getDevices to obtain the USB device list and USB interfaces, call usb.requestRight to request the device access permission, and call usb.connectDevice to obtain devicepipe as an input parameter.
System capability: SystemCapability.USB.USBManager
- Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
pipe | USBDevicePipe | Yes | Device pipe, which is used to determine the bus number and device address. |
iface | USBInterface | Yes | USB interface, which is used to determine the index of the interface to claim. |
force | boolean | No | Whether to forcibly claim the USB interface. The default value is false, indicating not to forcibly claim the USB interface. |
- Return value
Type | Description |
---|---|
number | Returns 0 if the USB interface is successfully claimed; returns an error code otherwise. |
- Example
let ret = usb.claimInterface(devicepipe, interfaces); console.log(`claimInterface = ${ret}`);
usb.releaseInterface
releaseInterface(pipe: USBDevicePipe, iface: USBInterface): number
Releases a USB interface.
Before you do this, ensure that you have claimed the interface by calling usb.claimInterface.
System capability: SystemCapability.USB.USBManager
- Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
pipe | USBDevicePipe | Yes | Device pipe, which is used to determine the bus number and device address. |
iface | USBInterface | Yes | USB interface, which is used to determine the index of the interface to release. |
- Return value
Type | Description |
---|---|
number | Returns 0 if the USB interface is successfully released; returns an error code otherwise. |
- Example
let ret = usb.releaseInterface(devicepipe, interfaces); console.log(`releaseInterface = ${ret}`);
usb.setConfiguration
setConfiguration(pipe: USBDevicePipe, config: USBConfig): number
Sets the device configuration.
Before you do this, call usb.getDevices to obtain the USB device list and device configuration, call usb.requestRight to request the device access permission, and call usb.connectDevice to obtain devicepipe as an input parameter.
System capability: SystemCapability.USB.USBManager
- Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
pipe | USBDevicePipe | Yes | Device pipe, which is used to determine the bus number and device address. |
config | USBConfig | Yes | USB configuration to set. |
- Return value
Type | Description |
---|---|
number | Returns 0 if the USB configuration is successfully set; returns an error code otherwise. |
- Example
let ret = usb.setConfiguration(devicepipe, config); console.log(`setConfiguration = ${ret}`);
usb.setInterface
setInterface(pipe: USBDevicePipe, iface: USBInterface): number
Sets a USB interface.
Before you do this, call usb.getDevices to obtain the USB device list and interfaces, call usb.requestRight to request the device access permission, call usb.connectDevice to obtain devicepipe as an input parameter, and call usb.claimInterface to claim a USB interface..
System capability: SystemCapability.USB.USBManager
- Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
pipe | USBDevicePipe | Yes | Device pipe, which is used to determine the bus number and device address. |
iface | USBInterface | Yes | USB interface to set. |
- Return value
Type | Description |
---|---|
number | Returns 0 if the USB interface is successfully set; returns an error code otherwise. |
- Example
let ret = usb.setInterface(devicepipe, interfaces); console.log(`setInterface = ${ret}`);
usb.getRawDescriptor
getRawDescriptor(pipe: USBDevicePipe): Uint8Array
Obtains the raw USB descriptor.
Before you do this, call usb.getDevices to obtain the USB device list, call usb.requestRight to request the device access permission, and call usb.connectDevice to obtain devicepipe as an input parameter.
System capability: SystemCapability.USB.USBManager
- Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
pipe | USBDevicePipe | Yes | Device pipe, which is used to determine the bus number and device address. |
- Return value
Type | Description |
---|---|
Uint8Array | Raw descriptor data. The value undefined indicates that the operation has failed. |
- Example
let ret = usb.getRawDescriptor(devicepipe);
usb.getFileDescriptor
getFileDescriptor(pipe: USBDevicePipe): number
Obtains the file descriptor.
Before you do this, call usb.getDevices to obtain the USB device list, call usb.requestRight to request the device access permission, and call usb.connectDevice to obtain devicepipe as an input parameter.
System capability: SystemCapability.USB.USBManager
- Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
pipe | USBDevicePipe | Yes | Device pipe, which is used to determine the bus number and device address. |
- Return value
Type | Description |
---|---|
number | File descriptor of the USB device. The value -1 indicates that the operation has failed. |
- Example
let ret = usb.getFileDescriptor(devicepipe);
usb.controlTransfer
controlTransfer(pipe: USBDevicePipe, contrlparam: USBControlParams, timeout?: number): Promise<number>
Performs control transfer.
Before you do this, call usb.getDevices to obtain the USB device list, call usb.requestRight to request the device access permission, and call usb.connectDevice to obtain devicepipe as an input parameter.
System capability: SystemCapability.USB.USBManager
- Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
pipe | USBDevicePipe | Yes | USB device pipe, which is used to determine the USB device. |
contrlparam | USBControlParams | Yes | Control transfer parameters. |
timeout | number | No | Timeout duration. The default value is 0, indicating no timeout. |
- Return value
Type | Description |
---|---|
Promise<number> | Returns the size of the transmitted or received data block if the control transfer is successful; returns -1 if an exception occurs. |
- Example
usb.controlTransfer(devicepipe, USBControlParams).then((ret) => { console.log(`controlTransfer = ${JSON.stringify(ret)}`); })
usb.bulkTransfer
bulkTransfer(pipe: USBDevicePipe, endpoint: USBEndpoint, buffer: Uint8Array, timeout?: number): Promise<number>
Performs bulk transfer.
Before you do this, call usb.getDevices to obtain the USB device list and endpoints, call usb.requestRight to request the device access permission, call usb.connectDevice to obtain devicepipe as an input parameter, and call usb.claimInterface to claim a USB interface.
System capability: SystemCapability.USB.USBManager
- Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
pipe | USBDevicePipe | Yes | USB device pipe, which is used to determine the USB device. |
endpoint | USBEndpoint | Yes | USB endpoint, which is used to determine the USB port for data transfer. |
buffer | Uint8Array | Yes | Buffer for writing or reading data. |
timeout | number | No | Timeout duration. The default value is 0, indicating no timeout. |
- Return value
Type | Description |
---|---|
Promise<number> | Returns the size of the transmitted or received data block if the control transfer is successful; returns -1 if an exception occurs. |
- Example
// Call usb.getDevices to obtain a data set. Then, obtain a USB device and its access permission. // Pass the obtained USB device as a parameter to usb.connectDevice. Then, call usb.connectDevice to connect the USB device. // Call usb.claimInterface to claim a USB interface. After that, call usb.bulkTransfer to start bulk transfer. usb.bulkTransfer(devicepipe, endpoint, buffer).then((ret) => { console.log(`bulkTransfer = ${JSON.stringify(ret)}`); });
usb.closePipe
closePipe(pipe: USBDevicePipe): number
Closes a USB device pipe.
Before you do this, call usb.getDevices to obtain the USB device list, call usb.requestRight to request the device access permission, and call usb.connectDevice to obtain devicepipe as an input parameter.
System capability: SystemCapability.USB.USBManager
- Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
pipe | USBDevicePipe | Yes | USB device pipe. |
- Return value
Type | Description |
---|---|
number | Returns 0 if the USB device pipe is closed successfully; returns an error code otherwise. |
- Example
let ret = usb.closePipe(devicepipe); console.log(`closePipe = ${ret}`);
USBEndpoint
Represents the USB endpoint from which data is sent or received. You can obtain the USB endpoint through USBInterface.
System capability: SystemCapability.USB.USBManager
Name | Type | Description |
---|---|---|
address | number | Endpoint address. |
attributes | number | Endpoint attributes. |
interval | number | Endpoint interval. |
maxPacketSize | number | Maximum size of data packets on the endpoint. |
direction | USBRequestDirection | Endpoint direction. |
number | number | Endpoint number. |
type | number | Endpoint type. |
interfaceId | number | Unique ID of the interface to which the endpoint belongs. |
USBInterface
Represents a USB interface. One USBConfig can contain multiple USBInterface instances, each providing a specific function.
System capability: SystemCapability.USB.USBManager
Name | Type | Description |
---|---|---|
id | number | Unique ID of the USB interface. |
protocol | number | Interface protocol. |
clazz | number | Device type. |
subClass | number | Device subclass. |
alternateSetting | number | Settings for alternating between descriptors of the same USB interface. |
name | string | Interface name. |
endpoints | Array<USBEndpoint> | Endpoints that belong to the USB interface. |
USBConfig
Represents the USB configuration. One USBDevice can contain multiple USBConfig instances.
System capability: SystemCapability.USB.USBManager
Name | Type | Description |
---|---|---|
id | number | Unique ID of the USB configuration. |
attributes | number | Configuration attributes. |
maxPower | number | Maximum power consumption, in mA. |
name | string | Configuration name, which can be left empty. |
isRemoteWakeup | boolean | Support for remote wakeup. |
isSelfPowered | boolean | Support for independent power supplies. |
interfaces | Array <USBInterface> | Supported interface attributes. |
USBDevice
Represents USB device information.
System capability: SystemCapability.USB.USBManager
Name | Type | Description |
---|---|---|
busNum | number | Bus address. |
devAddress | number | Device address. |
serial | string | Device SN. |
name | string | Device name. |
manufacturerName | string | Device manufacturer. |
productName | string | Product information. |
version | string | Version. |
vendorId | number | Vendor ID. |
productId | number | Product ID. |
clazz | number | Device class. |
subClass | number | Device subclass. |
protocol | number | Device protocol code. |
configs | Array<USBConfig> | Device configuration descriptor information. |
USBDevicePipe
Represents a USB device pipe, which is used to determine a USB device.
System capability: SystemCapability.USB.USBManager
Name | Type | Description |
---|---|---|
busNum | number | Bus address. |
devAddress | number | Device address. |
USBControlParams
Represents control transfer parameters.
System capability: SystemCapability.USB.USBManager
Name | Type | Description |
---|---|---|
request | number | Request type. |
target | USBRequestTargetType | Type of the request target. |
reqType | USBControlRequestType | Request control type. |
value | number | Request parameters |
index | number | Index of the request parameter value. |
data | Uint8Array | Buffer for writing or reading data. |
USBRequestTargetType
Represents the request target type.
System capability: SystemCapability.USB.USBManager
Name | Default Value | Description |
---|---|---|
USB_REQUEST_TARGET_DEVICE | 0 | Device. |
USB_REQUEST_TARGET_INTERFACE | 1 | Interface. |
USB_REQUEST_TARGET_ENDPOINT | 2 | Endpoint |
USB_REQUEST_TARGET_OTHER | 3 | Others |
USBControlRequestType
Enumerates control request types.
System capability: SystemCapability.USB.USBManager
Name | Default Value | Description |
---|---|---|
USB_REQUEST_TYPE_STANDARD | 0 | Standard |
USB_REQUEST_TYPE_CLASS | 1 | Class. |
USB_REQUEST_TYPE_VENDOR | 2 | Vendor |
USBRequestDirection
Enumerates request directions.
System capability: SystemCapability.USB.USBManager
Name | Default Value | Description |
---|---|---|
USB_REQUEST_DIR_TO_DEVICE | 0 | Request for writing data from the host to the device. |
USB_REQUEST_DIR_FROM_DEVICE | 0x80 | Request for reading data from the device to the host. |