I want to use ADXL372 sensor in instant-on mode. In my code, configurations are as follows.
-High instant-on threshold(30-40g)
-High-pass, low-pass filters are disabled, filter settling=16ms
For instant-on mode, datasheet says that when an impact beyond the selected threshold is detected(30-40g for me) the ADXL372 switches to full bandwidth measurement mode and begins outputting digital data.Therefore, I set INT2_MAP register to 0x01( Map data ready interrupt onto INT2). When the sensor is in instant-on mode and there is no external impact(sensor is stationary) , there is no interrupt on INT2. I confirmed this by using oscilloscope. When I apply around 10g shock, sensor interrupts although the threshold is 30-40g. Is there any problem about my configurations ? or Is there a problem about instant-on threshold? Even small shock values, sensor interrupts regardless of instant-on threshold. I am also sure that sensor is in instant on mode. I confirmed it by looking at power consumption.
Thank you for your post. I'm very sorry for the delay in response. Have you checked the POWER_CTL register? It might be that the INSTANT_ON_THRESH bit is set to trigger for 10 g.
I checked the POWER_CTL register. I set INSTANT_ON_THRESH bit for 30-40g. There is no problem in this register.
Have you tried quantifying the applied shock using a reference sensor? Do you have the impact profile measured from ADXL372? The impact that you have created could also depend on the contact material, impact angle, etc.
As shown in the data sheet, there might be some shift from part to part due to process. Do you have another part to test just to compare if that certain part has a higher shift?