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Thingy:91's ADXL372 instant on high treshold issue

Hi.

I'm having issues setting the instant on high threshold on the ADXL372 on the Thingy:91. I'm new to this, so I might be missing something obvious. I've updated the thingy firmware as specified on the getting started page. I'm setting the bit like this with the zephyr driver provided:

adxl372_reg_write_mask(dev_372, 
                    ADXL372_POWER_CTL,
        			ADXL372_POWER_CTL_INSTANT_ON_TH_MSK,
        			ADXL372_POWER_CTL_INSTANT_ON_TH_MODE(ADXL372_INSTANT_ON_HIGH_TH));

And have ensured that the 5th bit in the power control register (0x3F) is set before putting it into instant on mode, and that it stays that way.

adxl372_reg_write_mask(dev_372, 
                    ADXL372_POWER_CTL,
                    ADXL372_POWER_CTL_MODE_MSK,
                    ADXL372_POWER_CTL_MODE(ADXL372_INSTANT_ON));

From what i understand this is in accordance with the data sheet. Nevertheless the trigger seems to be just as sensitive when this bit is set, although the threshold should be 10-15g for low and 30-40g for high.

I've also tried to modify the driver in order so set the the accelerometer into high threshold from the start, but that doesn't seem to make a difference. Any insight to what could cause the issue, or what I am missing would be much appreciated. Im on NCS 1.4.0, but also tested briefly with a newer version.

-Sigurd

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  • Hello, 

    The latest official release is NCS v1.5.0, which was released yesterday.

    What application are you working on? Have you looked at our Asset Tracker application? Or the Zephyr ADXL372 sample found in: zephyr\samples\sensor\adxl372\
    Both samples uses the Sensors API (zephyr\include\drivers\sensor.h) to read from this sensor.

    Let me know how that works for you. 

    Kind regards,
    Øyvind

  • Yes, I've looked at both of those, and the program I'm working on is based on the ADXL372 sample. I'm using the sensor api to fetch data/read from the sensor and have no issues with that.

    The only issue i have is that when setting the the ADXL372 into INSTANT_ON mode (where it wakes from a low power sleep like state when it detects an impact) it doesn't seem to make a difference if I set the trigger to be high (30-40g) rather than low (10-15g) which is the default. It wakes up and starts to spit out data by equally light impacts. 

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  • Yes, I've looked at both of those, and the program I'm working on is based on the ADXL372 sample. I'm using the sensor api to fetch data/read from the sensor and have no issues with that.

    The only issue i have is that when setting the the ADXL372 into INSTANT_ON mode (where it wakes from a low power sleep like state when it detects an impact) it doesn't seem to make a difference if I set the trigger to be high (30-40g) rather than low (10-15g) which is the default. It wakes up and starts to spit out data by equally light impacts. 

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