LIS3DH high-pass filter not working

[microbob]

Posted on March 16, 2015 at 07:14

At work I am using the LIS3DH accelerometer to detect body motion.  It is configured for +/-2 gs, 50 samples per second, with Streaming FIFO.  The watermark works fine for determining when the FIFO needs to be emptied. 

The specification says that all three XY&Z axis can be high-pass filtered using CTRL_REG2 (address 0x21), but documentation is not totally clear.  I'm writing 0x11 to the filter register with no luck.   HPM1-HPM0 are set to 1, 0.  The cut off frequency bits are set to 0, 0 which should give a 1Hz cutoff at 50 samples per second.  Hopefully someone has documentation on configuring the high-pass filter that I do not.  Or someone has successfully implemented the filter and can tell me what they used. #lis3dh-hpfilter

[lovera]

Posted on September 06, 2015 at 22:58

Hi, I'm having a similar problem. Were you able to set it up properly? It seems that the datasheet is incomplete in order to properly set it up.

Could you let me know how to set up the cut off frequency? How do you know a 00 for the HPM bits correspond to a 1 hz cut off with 50 samples? Also do you know the difference between the Normal mode vs the reference signal filtering?

[alexanderpolleti9]

Posted on November 14, 2016 at 11:22

You find that kind of information not in the Datasheet but in the Application note AN3308