HID_USAGE_SENSOR_PROPERTY_REPORTING_STATE, It includes minimum and maximum values and the count and size of individual fields. Note the self-descriptive nature of this report. The following code example shows the HID feature report for the accelerometer. The input reports contain sensor readings: True or False for a switch, G-force values for an accelerometer or LUX for an ambient light sensor. The feature reports include a sensor’s current reporting state, its status, change sensitivity, and reporting interval (in addition to other possible properties). If your sensor supports one of the seven categories native to the class driver, its firmware will need to support specific feature and input reports. The following diagram illustrates the I/O model: For example, when the application requests a new change sensitivity or report interval, the driver packages these values into a feature report and uses this report to send the request to the sensor’s firmware.

The HID class driver sends feature reports to the sensor.

For example, for an accelerometer, the report contains the G-forces along the x-, y-, and z-axes). This report contains the actual sensor data. An input report is sent either upon request, or asynchronously in response to an event.

This report contains property data including the sensor’s change-sensitivity setting, its report interval, and its reporting state. A feature report is sent in response to a request from the driver.

The sensor sends either a feature report or an input report to the HID class driver.

If you are creating the firmware for a compatible sensor, you’ll need a basic understanding of the I/O model supported by the class driver. The custom sensor presents itself to the sensor API as a custom device with unique properties. This class allows a sensor manufacturer to integrate a device not found in the previous list: For example, a carbon monoxide sensor. In addition to the eleven sensors covered in the previous lists, the class driver also supports a Custom class. The following illustration depicts the flow of data back and forth from two sensor applications down through the driver stack and, finally, to the hardware itself. Starting with Windows 8, the Windows operating system includes an in-box sensor HID Class driver (SensorsHIDClassDriver.dll), that supports eleven types of sensors that communicate using the HID transport.

Hp what is hidclass driver