nRF52 with MPU9255: Power Save

[AlamKh]

Hi,

I am using the example nrf5-ble-mpu-simple from nrf5-mpu-examples-master to do the following:

a) send a BLE beacon advertisement (non connectable)

b) periodically sample the accelerometer readings from the connected MPU9255

c) change the advertisement data as per the read values

I am connecting the nRF52 as per the instructions on https://devzone.nordicsemi.com/f/nordic-q-a/31155/nrf52-with-mpu9255 (as given in the image below)

The problem I am facing is that the MPU is drawing too much current. Is there a simple way to configure the MPU so that it wakes up only when I need to read the accelerometer readings and

then put it in sleep mode (low current)?

[Jared]

Hi,

I'm not sure how the accelerometer will react when the nRF is configured to sleep in SYSTEM OFF ( you would have to test and see) but there are several ways to wake up the nRF from  SYSTEM OFF sleep as described here. Note that waking up from SYSTEM OFF will reset the application. If you don't want to reset the application upon wake-up, then you could try using SYSTEM ON sleep instead by calling a  __WFE. This will keep the nRF in IDLE mode while it waits for an event, the tradeoff is the higher current consumption versus using SYSTEM OFF.