# Modules.CoreMotion.DeviceMotion

A bitmask that you can bitwise-AND with the ATTITUDE_REFERENCE constants.

For example to determine if ATTITUDE_REFERENCE_FRAME_X_MAGNETIC_NORTH_Z_VERTICAL is available on device.

var frames = CoreMotion.DeviceMotion.availableAttitudeReferenceFrames();
if (frames & CoreMotion.ATTITUDE_REFERENCE_FRAME_X_MAGNETIC_NORTH_Z_VERTICAL) {
    // do something here
}

If device motion is active, this property returns the reference frame currently in use. If device motion is not active but has been active since the app was last launched, this property returns the last frame used. If device motion has not been active since the app was last launched, this property returns the default attitude reference frame for the device. Possible reference frames include ATTITUDE_REFERENCE_FRAME_X_ARBITRARY_Z_VERTICAL, ATTITUDE_REFERENCE_FRAME_X_ARBITRARY_CORRECTED_Z_VERTICAL, ATTITUDE_REFERENCE_FRAME_X_MAGNETIC_NORTH_Z_VERTICAL, and ATTITUDE_REFERENCE_FRAME_X_TRUE_NORTH_Z_VERTICAL.

An app that is receiving device-motion data after calling startDeviceMotionUpdatesUsingReferenceFrame or startDeviceMotionUpdates with no callback, need to periodically check the value returned by this method and process the device-motion data.

Indicates whether startDeviceMotionUpdates or startDeviceMotionUpdatesUsingReferenceFrame has been called since stopDeviceMotionUpdates.

The system supplies device-motion updates to the callback passed to startDeviceMotionUpdatesUsingReferenceFrame or startDeviceMotionUpdates at regular intervals determined by the value passed to this method. The interval units are in milliseconds. The value of this property is capped to minimum and maximum values; the maximum value is determined by the maximum frequency supported by the hardware. If your app is sensitive to the intervals of device-motion data, it should always check the timestamps of the delivered device-motion event to determine the true update interval.

When a device requires movement (for example, to calibrate the compass), the value of this property indicates if the system's device-movement display should be shown. When a device requires movement, the callback for setDeviceMotionUpdateInterval or startDeviceMotionUpdatesUsingReferenceFrame reports the ERROR_DEVICE_REQUIRES_MOVEMENT error once. By default, this is set to false.

If a callback is passed to this method, it will be called whenever there is an update. The frequency of these updates can be controlled using the setDeviceMotionUpdateInterval method. If no callback is passed, the device-motion data can be accessed using the getDeviceMotion method. To stop the delivery of events, call the stopDeviceMotionUpdates method.

If a callback is passed to this method, it will be called whenever there is an update. The frequency of these updates can be controlled using the setDeviceMotionUpdateInterval method. If no callback is passed, the device-motion data can be accessed using the getDeviceMotion method. To stop the delivery of events, call the stopDeviceMotionUpdates method.