CMDeviceMotion returns 0 values for magnetic field

Question

I am developing iOS app with compass functionality. I have tried to use CMMagnetometerData updates which give uncalibrated, but normal results.

After t

Answer 1

Finally, according to my own observations:

1) Use startDeviceMotionUpdatesUsingReferenceFrame:toQueue:withHandler:with referenceFrame NOT equal to allZeros or XArbitraryZVertical.

2) Set showsDeviceMovementDisplay to true.

After few zero-value updates with accuracy CMMagneticFieldCalibrationAccuracyUncalibrated it will normalise.