Device methods

Device methods

The sensor firmware supports several helper methods that perform tasks like supporting events and managing power.

Device methods for intelligent sensors

For intelligent sensors (like HID), the firmware includes support for methods that handle events and manage power. The pseudocode demonstrates these tasks using the HIDSensorDeviceEvent and HIDDeviceManagePower methods.


HIDSensorDeviceEvent(sensorID) // Driver issues USB/HID “SEND_INPUT” command to the sensor
{
    // an event has occurred on the sensor device
    // this could be one of several things, not only just a data update event
    if (event == eventData) //ex data change exceeded effectiveCS[]
    {
        if (effectiveRS = reportingStateAllEvents)
        {
            Set sensorState = sensorStateReady
            Set sensorEvent = eventTypeCS (or data update as appropriate)
            Send async data to driver //received in driver by DDIHandleAsyncDataEvent()
        }
        else
        {
            //do nothing
        }
    }
    else if (event == eventStateChange)
    {
        // if this event is not a data update event
        // then no matter what the reporting state and
        // power state (as long as power is on) 
        // of the device then send the event
        // to the driver
        Set sensorState = current sensor state
        Set sensorEvent = type for this event
        Send async data to driver //received in driver by DDIHandleAsyncDataEvent()
    }
}



HIDDeviceManagePower(powerState)
{
    if (powerstate for all sensors is == powerStatePowerOff)
    {
        Turn the power off to all sensors
        Turn off power to the device
    }
    else if (powerState for any sensor is >= powerStateLowPower)
    {
        Turn on power to the device
        Turn on power to the sensor
        sensorState = sensorStateInitializing
        Send sensor state to sensor asynchronously using SEND_INPUT USB/HID command

        Initialize the sensor
        if (sensor is ready)
        {
            Set sensorState = sensorStateReady
            Send sensorState to sensor asynchronously using SEND_INPUT USB/HID command
        }
        else if (sensor is never is initialized and becomes ready)
        {
            Set sensorState = sensorStateError
            Send sensorstate to sensor asynchronously using SEND_INPUT USB/HID command
        }
    }
}


Device methods for simple sensors

For simple sensors (like SPB), the firmware includes support for a method that handles events. The pseudocode demonstrates this task using the SpbSensorDeviceEvent.


SpbSensorDeviceEvent(sensorID)
{
    // an interrupt has occurred on the sensor device
    // this could be one of several things, not only just a data update event
    if (event == eventData) //ex data change exceeded effectiveCS[]
    {
        if (effectiveRS = reportingStateAllEvents)
        {
            Acknowledge device interrupt
            Query data synchronously from the device via SPB

            Set sensorState = sensorStateReady
            Set sensorEvent = eventTypeCS (or data update as appropriate)
            
            Invoke DDIHandleAsyncDataEvent(sensorID)
        }
        else
        {
            //do nothing
        }
    }
    else if (event == eventStateChange)
    {
        // if this event is not a data update event
        // then no matter what the reporting state and
        // power state (as long as power is on) 
        // of the device then send the event
        // to the driver. Note not all simple devices
        // will support state change eventing. 
        
        Acknowledge device interrupt
        Query state synchronously from the device via SPB

        Set sensorState = current sensor state
        Set sensorEvent = type for this event
    }
}


 

 

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