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Required descriptors

This topic describes the required descriptors that a Windows pointer device must provide.

Required operating system descriptors

If your device uses the internal USB bus, you must enable the USB selective suspend feature for your human interface device (HID) device by using the USB Microsoft OS Descriptors. With a properly formatted Microsoft OS extended property descriptor, the USB selective suspend feature can be enabled automatically whenever the HID device is connected.

For more details about how the Microsoft OS extended property descriptor can be used to automatically enable selective suspend, see Microsoft OS Descriptors.

Required USB HID descriptor

The following table shows the required USB HID descriptor. For more information, see section 6.2.1 in Device Class Definition for Human Interface Devices (HID) Version 1.11.

Member Size in bytes Description

bLength

1

Size of the descriptor

bDescriptorType

1

Type of descriptor

bcdHID

2

HID version number

bCountryCode

1

Country code

bNumDescriptors

1

Number of descriptors

bDescriptorType

1

Descriptor type

bDescriptorLength

2

Length of the descriptor

 

Required I2C HID descriptor

The following table shows the required I2C HID descriptor.

Member Size in bytes Description

bLength

2

The length of the complete HID descriptor, in bytes

bcdVersion

2

The version number, in binary coded decimal (BCD) format

dwReportDescLength

2

The length of the Report descriptor, in bytes

wReportDescRegister

2

The register index containing the Report descriptor

wInputRegister

2

The register number to read the input report, in unsigned bytes

wOutputRegister

2

The register number to send the output, in unsigned bytes

wVendorID

2

USB-IF assigned Vendor ID

wDeviceID

2

Device ID

wRevisionID

2

Firmware version number

 

Required device attributes

The following HID properties must be provided in the device attributes. The reporting of these device attributes is bus specific. Consult the HID specific guidance for your choice of bus.

Member Description

bSize

Size of the Device descriptor

wVendorID

Vendor Id

wProduct

Product Id

Version Number

Firmware version number

 

Required HID strings

The following strings must be supported by devices that support Windows pointer functionality:

  • Manufacturer Name
  • Product String

For more information, see section E.11 in Device Class Definition for Human Interface Devices (HID) Version 1.11.

 

 

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