BMA400 datasheet only provides rms noise for +/-4g range. What about 8 and 16g ranges?
I am using normal mode, 8g range, 200Hz sampling rate and x2 oversampling (osr=2), 24mg hysteresis, xyz,
Sensor is steady-state, no vibration. But once in a while I am getting falsely activity detection interrupts.
Trying to figure out whether it is because of noise, or noise + some slight vibration.
Hi,
Thanks for the detailed description. I used our APP2.0 base board and BMA400 shuttle board and DD2.0 GUI SW to test your settings. It works as expected. The VDD of BMA400 is 3.3V.
BMA400 Gen1 interrupt is mapped to INT1 pin with push-pull and active-low as shown below.
Gen1 configurations are as shown below the same as yours.
When I place the boards on the desk with no motion, Gen1 signal stays low while INT1 signal stays high. When I tap the boards, I can see many pulses on INT1 pin the same as yours. This is because INT is latched and when you read status register every time in ISR, INT pin will be cleared. If you don't read status, then INT pin will stay low all the time which means that the interrupt is latched. In order to reduce the number of pulses, you may do some tasks inside ISR or outside ISR after you see the Gen1 interrupt on INT pin. Then you may add delay of 100ms for example. Finally you can read status register to clear the latched INT1 signal.
To sum up, BMA400 noise level is not related to 3.3V or 1.8V, +/-4g or +/-8g, +/-16g. You can fine tune the threshold and duration values to adjust the sensitivities to motion detection.
Thanks.
