BMI270: SPI current consumption

[peterl]

What is the expected current consumption when reading and writing via SPI to the BMI270?

We have noticed an increase in current consumption of roughly 1mA when reading sensor data from the BMI270 at a measurement rate of 50Hz. Is this expected?

Thank you very much.

[Minhwan]

Hello Peterl, 

I think the bmi270 is not in low power mode so that the current consumption would be higher than you expect. 

Once interface is ready, please follow our sequence page 15 ~ 18. 

Especially, page 18 is talking about setting low power 🙂 

Thanks, 

[peterl]

Thank you very much for your response.

We believe we are following the instructions and are in low power mode. Just as an side, we are using the latest version of the Bosch Sensortec API to configure the IMU.

For reference, the current consumption is around 10uA when the IMU is running and we are not communicating via SPI. 

As soon as we attempt to read the sensor data via SPI this increases to 1mA. We are struggling to understand why the act of reading the measurement data via SPI increases the power consumption.

Would you have any suggestions of how this can be avoided?

Thank you very much and all the best

Peter

[Minhwan]

Hello peterl, 

Could you capture your data log using logic analyzer and share it with me? 

As long as you totally follow our API and hardware is okay, it should work. 

Thanks, 

[peterl]

Dear Minhwan,

Thank you very much for your message.

Unfortunately, we don't have a logic analsyer, so can't caputre the data.

We carried out some further tests. We also have got a BMM150 connected ot the aux interface and we noticed that it it is the data read from this device via the aux interface which si causing the issue with the increased current. We are using the Bosch API to read the data.

Would you know why this increased current consumption occurs? It is much more than what we expect, when running the magnetometer.

Thank you very much and all the best

Peter

[Minhwan]

Hello Peterl, 

Okay, let me clear your issue. 

Now, you are using BMI270 and BMM150 both, and BMM150 is using thru BMI270 right? 

And, BMI270 current consumption is 1mA when you read some data regarding BMM150. 

Is that correct? 

Thanks,