nRF52840 Low Frequency Noise Sources

[mstanisz]

Hi,

I am using an Adafruit nRF52840 Express with a sensor board attached to it.  I'm noticing that my sensor IC is reading about 3-6dB higher noise in the 10-50Hz range (and likely higher) when the Bluefruit BLE stack is running from Adafruit which is based on the s140 6.1.1 softdevice.  I have been unable to dig into the BLE subsystem so far and find the possible noise source.

Would you have a suggestion as to where in the softdevice I should focus on to review possible noise sources?

Best,
Matt

[mstanisz]

Hi Carl!

Thanks for your input, that does make a lot more sense that the clock configruation is getting programmed twice.  We have gone through each sensor and tuned the HW as best we can for the issue.  I think we've gotten it as clean as it's going to get given we're using a module + shield, so I think we're all set.  I went ahead and marked your answer as the clock configuration was my main question.  If Adafruit comes up with more input, I'll post again.

Cheers,

Matt