Troubleshooting USB, Bluetooth, and HID device access
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Troubleshooting USB, Bluetooth, and HID device access (Windows Store apps)

In Windows 8.1, all developers can use the device protocol APIs to write Windows Store apps that communicate with USB, Human Interface Devices (HID), Bluetooth GATT, and Bluetooth RFCOMM peripheral devices. The ways in which your app can communicate with these devices varies per API, so you may experience issues if you attempt to use an API in a way that's not supported. This topic provides an overview of the device protocol APIs, introduces the DeviceAccessInformation class, and lists some possible causes of device access issues. For more info about the USB, HID, and Bluetooth APIs, see Communicating with peripheral devices.

Note  OEMs can also use the device protocol APIs to access devices that are internal to the PC enclosure. To access internal devices, OEMs must specify their app in device metadata as a privileged app for the system container. For more info, see Windows Store device apps for internal devices.
 

API overview

Device access varies; it depends on the API you're using:

Device protocol APINamespaceAccess type
USB Windows.Devices.Usb exclusive read & exclusive write
Bluetooth GATT Windows.Devices.Bluetooth.GenericAttributeProfile exclusive read & exclusive write
Bluetooth RFCOMM Windows.Devices.Bluetooth.Rfcomm shared read & shared write
HID Windows.Devices.HumanInterfaceDevice shared read & exclusive write

 

Checking device access

In Windows 8.1, the user can grant or deny access to the device. To check if your app has access, you can use the DeviceAccessInformation class and the DeviceAccessStatus enumeration. If it's been denied access to the device, DeviceAccessStatus can indicate if the access was denied by the user or the system.

Device access issues

Issue: my app can't access a USB device

  • Possible cause: The device driver is not Winusb.sys or Winusb.sys is not installed. If the device driver is not installed automatically, you must do so manually. For more info, see Writing apps for USB devices.

  • Possible cause: Your app's manifest file is missing the DeviceCapability element or it's not properly configured. For more info, see How to specify device capabilities for USB.

  • Possible cause: Your device does not belong to one of the device classes supported by the API. For more info about the supported device classes, see Writing apps for USB devices.

  • Possible cause: The user has not granted the app permission to access the device. For more info, see FAQs for USB, Bluetooth, and HID APIs.

Issue: my app can't access a Bluetooth device

Issue: my app can't access a HID device

Issue: my app can't access an internal device

  • Unless you're an OEM (or a component supplier that's working with an OEM), this is by design.

    Internal device access is limited to OEMs. To access an internal device, the app must be specified in device metadata as a privileged app for the system container. For more info, see Windows Store device apps for internal devices.

Related topics

Integrating devices, printers, and sensors
Communicating with peripheral devices
Writing apps for USB devices
Supporting human interface devices (HID)
Supporting Bluetooth devices
How to specify device capabilities for USB
How to specify device capabilities for Bluetooth
How to specify device capabilities for HID

 

 

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