harmony 鸿蒙USB Usage Guidelines

2022-08-09
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USB Usage Guidelines

The following procedure uses bulk transfer as an example.

Procedure

Obtain a USB service instance.

static OHOS::USB::UsbSrvClient &g_usbClient = OHOS::USB::UsbSrvClient::GetInstance();

Obtain the USB device list.

std::vector<OHOS::USB::UsbDevice> deviceList;
int32_t ret = g_usbClient.GetDevices(deviceList);

Apply for device access permissions.

int32_t ret = g_usbClient.RequestRight(device.GetName());

Open the USB device.

USBDevicePipe pip;
int32_t et = g_usbClient.OpenDevice(device, pip);

Configure the USB interface.

ret = g_usbClient.ClaimInterface(pip, interface, true); // **interface** indicates an interface of the USB device in **deviceList**.

Transfer data.

srvClient.BulkTransfer(pipe, endpoint, vdata, timeout);

Parameter description: - pipe: pipe for data transfer of the USB device opened. - endpoint: endpoint for data transfer on the USB device. - vdata: binary data block to be transferred or read. - timeout: timeout duration of data transfer.