Config and Pinout

RE: Config and Pinout

SteinC — Fri, 24 Apr 2026 18:50:21 GMT

Hi , thanks for feedback. We are disabling uart0 in main because we have found that we need to "shut down" PDM after recording before starting up SD to write the recording-data.(SPI sync) We did this successflly with RAK11720 and a analog mic but are struggling with the PDM and the SD on this kit. We are using DMIC. Have not been focusing on the PDM clock so far. We got some test software from RAK which they claime worked on this kit but it failed. Do you have some test routines that we could use just to verify the setup of this kit?

RE: Config and Pinout

Maria Gilje — Fri, 24 Apr 2026 12:54:56 GMT

Hello,

Thank you for your patience and for updating with the proper overlay file.

Pins P0.20 and P0.19 are configured to uart0 by default. Where do you disable uart0 or change its pin configuration? Potentially, choose other pins for PDM if you are using uart0.

If the pins are not the issue, verifying the PDM clock frequency is a good next step.

Best regards,

Maria

RE: Config and Pinout

SteinC — Mon, 20 Apr 2026 07:46:27 GMT

Hi, sorry did not see that. But its my mailsystem that "helps". Here is the code from VSC.

/ {

aliases {

disk0 = &sdhc0;

};

/* Enable PDM */

&pdm0 {

status = "okay";

pinctrl-0 = <&pdm0_default>;

pinctrl-names = "default";

};

/* Define PDM pins */

&pinctrl {

pdm0_default: pdm0_default {

group1 {

psels = <NRF_PSEL(PDM_CLK, 0, 20)>,

<NRF_PSEL(PDM_DIN, 0, 19)>;

};

/* Enable SPI0 for SD card */

&spi0 {

status = "okay";

compatible = "nordic,nrf-spim";

cs-gpios = <&gpio0 26 GPIO_ACTIVE_LOW>;

sdhc0: sdhc@0 {

compatible = "zephyr,sdhc-spi-slot";

reg = <0>;

status = "okay";

spi-max-frequency = <400000>;

mmc {

compatible = "zephyr,sdmmc-disk";

disk-name = "SD";

status = "okay";

};

RE: Config and Pinout

Turbo J — Mon, 20 Apr 2026 07:01:49 GMT

That overlay looks like it gotten heavily maimed by AI translation. You MUST NOT translate overlay files - switch any information source to native english without any translation active.

RE: Config and Pinout

SteinC — Sun, 19 Apr 2026 13:01:15 GMT

Hi, thanks for swift answer, this is how our overlay looks like.:

/ {

aliaser

disk0 = &sdhc0;

};

/* Aktiver PDM */

&pdm0 {

status = "ok";

pinctrl-0 = <&pdm0_standard>;

pinctrl-navn = "standard";

};

/* Definer PDM-pinner */

&pinctrl {

pdm0_standard: pdm0_standard {

gruppe1

psels = <NRF_PSEL(PDM_CLK, 0, 20)>,

<NRF_PSEL(PDM_DIN, 0, 19)>;

};

/* Aktiver SPI0 for SD-kort */

&spi0 {

status = "ok";

kompatibel = "nordisk, nrf-spim";

cs-gpios = <&gpio0 26 GPIO_ACTIVE_LOW>;

sdhc0: sdhc@0 {

kompatibel = "zephyr, sdhc-spi-spor";

reg = <0>;

status = "ok";

spi-maks-frekvens = <400000>;

mmc

kompatibel = "zephyr, sdmmc-disk";

disknavn = "SD";

status = "ok";

};

RE: Config and Pinout

Maria Gilje — Thu, 16 Apr 2026 14:15:00 GMT

Hello,

You need to ensure that the pins you are using are correctly configured. I.e. that NFC are pins configured as GPIOS with &uicr { nfct-pins-as-gpios; }; in your board overlay if you are using them, or that the module have the pins accessible/routed to the base board. Other than that you should be able to choose pins freely.

May I ask if you are using some sample firmware for your application? I.e. the DMIC driver sample? Please note that the frequency settings need to be changed in main.c to reflect the frequencies the ones which the RAK18030 microphone supports.

It is also possible to share your overlay to get a second opinion on it from me (or community members), but please note that I am not familiar with the WisBlock system, so I would need some time to get to know it to provide proper feedback.

Best regards,

Maria