BMX160 read uncompensated magnetometer data

[timmbo]

Hi all,

I have a very short but important question:

Ineed to read uncompensated magnetometer values from the BMX160 (no api compensation) in uT. Unfortunately I do not know the LSB to uT conversion factor on XY and on Z for the raw data. Is it just LSB * 0.3 for both? The result seems very inaccurate (compared to the temperature compensated values).

According to datasheet:

Range XY: +/- 1300uT, 13 bit signed integer -> I assumed -1300 / -4096 = 0.31738 as conversion factor (which seems to be quite correct when comparing it to compensated values)

Range Z: +/- 2500uT, 15 bit signed integer -> I assumed -2500 / -16384 = 0.15258 as conversion factor (values cannot be correct)

Can you please help about the conversion factor LSB to uT for raw data?

Thanks in advance,

Timm

[FAE_CA1 · Accepted solution]

Hi Timm,

Sorry about my mistake. BMM150 x and y axes (based on Bosch flip-core technology) also use z axis (based on Hall effect) r_hall input value for temperature compensation.

The factory trimmed dig_xyz1 value in each BMM150's NVM is used as a reference to the input of r_hall. If you don't want to do temperature compensation on BMM150 x/y/z axes, then you can pass constant r_hall = dig_xyz1 to those functions.

Thanks.

[timmbo]

Hey there, thanks a lot for your excellent support! Everything clear now 🙂