Config and Pinout

[SteinC]

Hi, I'm using a WisBlock setup with:
• RAK19001 base board
• RAK4631 core
RAK18030 microphone in IO slot A
• RAK15002 microSD in IO slot B
I'm running Zephyr / nRF Connect SDK v3.2.4 on nRF52840.
The SD card works and WAV files are written correctly. The PDM driver also initializes and captures buffers successfully. However, the captured microphone data is not real audio. The raw blocks show a large startup transient, then an exponential decay, and then all samples become a constant value (around 7). Speaking or playing a tone directly into the microphone does not change the captured pattern.
We have already tested multiple PDM pin combinations in the Zephyr overlay, different channel selections, and also tried another microphone module. The behavior stays the same.
Could you please confirm the correct routing / pinapping / enable requirements for using RAK18030 on RAK19001 with RAK4631, specifically with RAK152 also installed in the other IO slot?

[Simonr]

Hi again Stein

What kind of sample are you looking for here? We don't test specifically with RAK boards since they are a third party module. But the low power sample projects in the previously linked DevAcademy course showcase how to put the device in a low power mode. Repos for that can be found here: https://github.com/NordicDeveloperAcademy/bt-lowpow 

Regarding the example you got from RAK, what nRF Connect SDK version is this based on? If it's not too long ago, migrating to a newer SDK version that supports the newer PM routines should be possible.

If you want to send us a couple of modules so we can try on our end, that's something we can do as well. It's hard for us to guess to what this 950µA comes from without having the HW ourselves.

Best regards,

Simon