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ADXL362 Activity and Inactivity detection

Hi

I am FAE in Jaoanese distributor.

Our customer evaluates ADX362 using Activity and Inactivity detection with Link mode and configured as referenced.

The ADXL362 often switches between standby and measurement modes due to customer’s product specifications.

Our customer has already made several prototypes, but depending on the device, there are devices that detect ACT immediately after switching from standby to measurement mode and devices that detect INACT.

Is it undecided whether it will be in the Activity detection waiting state or the  Inactivity  detection waiting state immediately after switching to the measurement mode?

Best regards

N.Kokubo

  • Hi Kokubo, 

    can you please share the register configurations? that will help me to understand where the issue might be. 

    thanks, 

    Pablo.

  • Hi Pablo san

    ADXL372 is configured the followg register setting.

    address  data

    0x2d 00
    0x27 1F
    0x23 FF
    0x24 07
    0x25 01
    0x26 00
    0x20 32
    0x21 00
    0x22 0d
    0x2d 02

    ADXL362 often switches between 0x2d 00 and 0x2d 02.

    In Resting state, there are devices that detect ACT immediately after switching from standby to measurement mode and devices that detect INACT.

    Is it undecided whether it will be in the Activity detection waiting state or the  Inactivity  detection waiting state immediately after switching to the measurement mode?

    Best regards

    N.Kokubo

  • Hi Kokubo, 

    What you provided is not the complete register map configurations, from the setting looks like activity is enabled in referenced mode only for X axis to a value near 200g, but there is no information about inactivity threshold and modes. 

    If possible i would like to have settings from register 0x20 to 0x3F. 

    Can you please confirm if the customer is taking this precaution ? 

    Thanks, 

    Pablo. 

  • Hi Pablo san

      I am consultng about ADXL362. ADXL372 is my typo.

      ADXL362. regsiter adress is from 0x00 to 0x2E.

      ADXL362 is configured the followg register setting.

       Inactivity threshold is defind at 0x23 and 0x24.

    address  data

    0x2d 00
    0x27 1F
    0x23 FF
    0x24 07
    0x25 01
    0x26 00
    0x20 32
    0x21 00
    0x22 0d
    0x2d 02

    ADXL362 often switches between 0x2d 00 and 0x2d 02.

    In Resting state, there are devices that detect ACT immediately after switching from standby to measurement mode and devices that detect INACT.

    Is it undecided whether it will be in the Activity detection waiting state or the  Inactivity  detection waiting state immediately after switching to the measurement mode?

    Best regrads

    N.Kokubo

  • Hi Kokubo, 

    Below is a summary of the customer configurations: 

    - 2g range, 100Hz ODR and BW = 1/4 of ODR 

    - Activity: threshold = 50mg, timer = 13 samples 

    - Inactivity: threshold = 1.024g timer, 1 sample

    In referenced mode, the first sample is taken in absolute mode and used as the "reference" value. being the activity threshold so low and the inactivity threshold higher, either of them can trigger an interrupt. 

    Can I ask what is the application and why is the activity threshold so low and inactivity so high? I general, activity threshold is set to a higher value than inactivity threshold.  Is the customer interested in detecting activity or inactivity?

    Please provide as many details as possible about the applications, so I can help figure out what should be the correct settings. 

    Thanks, 

    Pablo. 

     

  • Hi Pablo san, 

    Our customer has already made several prototypes, but depending on the device, there are devices that detect ACT immediately after switching from standby to measurement mode and devices that detect INACT.

    Our customer original Inactivity threshold is 50mg and had the same problem then.

    They experimentally changed the Inactivity threshold from 50mg to 1g and found the same problem.

    Is it undecided whether it will be in the Activity detection waiting state or the  Inactivity  detection waiting state immediately after switching to the measurement mode?

    Could you please my question?

     

    Best regards

    N.Kokubo

  • Hi Kokubo, 

    for activity and inactivity = 50mg they just need to make the inactivity timer higher than the activity timer, so for their case inactivity timer should be >13 samples. 

    0x2d 00
    0x27 1F
    0x23 32
    0x24 00
    0x25 0E
    0x26 00
    0x20 32
    0x21 00
    0x22 0d
    0x2d 02

    That should solve the issue. 

    Let me know if it works! 

    Pablo. 

  • Hi

    I confirmed the correct result.

    But our customer has 2 questions.

    (1)Is it undecided whether it will be in the Activity detection waiting state or the  Inactivity  detection waiting state immediately after switching to the measurement mode?

    (2)Why should inactivity timer be >13 samples. 

    Could you please my questions?

    Best regards

    N.Kokubo

  • Hi Kokubo, 

    1) yes, depending the settings for activity and inactivity. If activity and inactivity are set to a very low threshold either of them can happen. 

    2) for the customer configs increasing the inactivity timer ensures that activity should happen first, as its timer is lower. 

    Regards, 
    Pablo. 

  • Hi Pablo san

    1)I understood it was undecided whether it will be in the Activity detection waiting state or the  Inactivity  detection waiting state after switching to the measurement mode when activity and inactivity was set to a very low threshold. 

    2)My I confirm your answer? 

     If Inactivity timer is shorter than Activity timer, does ADXL362 go to inactivity waiting state first?

           If Inactivity timer is longer than Activity timer, does ADXL362 go to activity waiting state first?

    Regards, 
    Kokubo,