USB Usage Guidelines

The following procedure uses bulk transfer as an example.

Procedure

  1. Obtain a USB service instance.
static OHOS::USB::UsbSrvClient &g_usbClient = OHOS::USB::UsbSrvClient::GetInstance();
  1. Obtain the USB device list.
std::vector<OHOS::USB::UsbDevice> deviceList;
int32_t ret = g_usbClient.GetDevices(deviceList);
  1. Apply for device access permissions.
int32_t ret = g_usbClient.RequestRight(device.GetName());
  1. Open the USB device.
USBDevicePipe pip;
int32_t et = g_usbClient.OpenDevice(device, pip);
  1. Configure the USB interface.
ret = g_usbClient.ClaimInterface(pip, interface, true);
**interface** indicates an interface of the USB device in **deviceList**.
  1. Transfer data.
srvClient.BulkTransfer(pipe, endpoint, vdata, timeout);
  • pipe indicates the pipe for data transfer of the USB device opened.
  • endpoint indicates the endpoint for data transfer on the USB device.
  • vdata indicates the binary data block to be transferred or read.
  • timeout indicates the timeout duration of data transfer.
  1. Close the USB device.
ret = g_usbClient.Close(pip);