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]

Hei Stein

Takk for ærlige tilbakemeldinger!

I'll continue in English since other users might read this as it is a public ticket.

Regarding sleep and optimizing current consumption. With the nRF52840, the idle current consumption should be in the single digit µA range, even in power ON idle. Drawing 900+µA means something external is most likely running, as very few of the peripherals on the nRF52840 are able to draw that much power. I assume this is the whole system's current consumption, correct?

We released a Power optimization course on DevAcademy here https://academy.nordicsemi.com/courses/designing-low-power-bluetooth-le-products/lessons/lesson-1-power-consumption-essentials/?version=v3.3.0 and also have the optimization recommendations from our documentation pages here: https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/test_and_optimize/optimizing/power_general.html 

In the Zephyr RTOS, the application should move to the idle thread (low power) as long as nothing else in the application is requesting any clocks/peripherals. So I assume either the microphone, SD card, or similar is left running in your application causing this 900µA current consumption.

Best regards,

Simon

[SteinC]

Hi, we have removed all io units from the Wisboard, measured the wisboard separate to 6 microamps, put the RAK4361 back in, still not gotten under 950µA. Got an example referred to us by RAK on Git but its to old using old PM routines. So we are struggling. Would be great to get a small example to verify that we understand the docs correctly.