FXOS8700CQ on FRDM-K64F-AGM01 board calibration questions.

[shawncrossland]

All,

I hope this was not already asked and answered somewhere else. I am using NXP's FXOS8700CQ magnetic sensor with FRDM-K64F-AGM01 board. I have downloaded from NXP website the Freedom Sensor Toolbox (CE) V2.5.0 software for NXP's 9-axis orientation sensor demonstration project, specifically. In the main form, I click the "start" icon, then I click the "Sensors" tab, allowing to view the real-time calibrated magnetometer sensor frame data, Bc[X], Bc[Y], and Bc[Z], in micro Tesla. 

Question #1:

As soon as I move the magnetic sensor (FXOS8700CQ with the Freedom board), is auto-calibration done automatically and continuously without stop, in this demonstration project? 

Question #2:

If so, according to document AN4459, I understand that this will be the hard-iron calibration only (which is fine with me).

Will this be in the "calibrate-then-compensate" state, or in the "calibrate-and-compensate" state? These two states are differentiated in AN4459.

Thank you very much,

-Shawn

[shubhadippaul-b]

Hi Shawn,

Answer to your Question #1:

Yes, Magnetic Calibration (MagCal Algorithm) run automatically and continuously as long as the Demo is running. When you run the Demo for the first time, there will be a Magnet Icon below Start Button indicating calibration is pending. After you Hit start button calibration starts and you should now rotate the Board across all AXIS or figure of 8 to enable the algorithm to acquire diverse samples and get an acceptable degree of Hard and Soft Iron calibration.

Answer to your Question #2:

The Demo employs Hard as well as Soft iron Calibration which is applicable for eCompass (FXOS8700).

Please refer to Application Note AN4246 for details.

[shawncrossland]

Thank you very much for your responses. :smileyhappy:

-Shawn