zephyr 3.5.0 I2S on nrf52840

RE: zephyr 3.5.0 I2S on nrf52840

ms360 — Tue, 14 Oct 2025 22:28:00 GMT

Elfving, My Salae logic analyzer was damaged.
The hexfiles are working and all 4 i2s lines are working.

RE: zephyr 3.5.0 I2S on nrf52840

ms360 — Tue, 14 Oct 2025 15:03:35 GMT

1817.zephyr.hex only shows me LRCLK and SDOUT. Same failure mode.
What are the chances I have 2 faulty PCA10056 PCBS?
The blinky test proved those pins are working.

I'll send him my hex file. good call.

RE: zephyr 3.5.0 I2S on nrf52840

Elfving — Tue, 14 Oct 2025 09:19:48 GMT

devzone.nordicsemi.com/.../1817.zephyr.hex

Have you tried sending him your hex file? The only thing I can imagine being wrong then is the sw on your side/build environment.

Regards,

Elfving

RE: zephyr 3.5.0 I2S on nrf52840

ms360 — Mon, 13 Oct 2025 14:10:15 GMT

you mentioned you had an i2s build with some pins wiggling.
The aforementioned build from a colleague is working for him, but he sent me the same hexfile and it does NOT work for me.

RE: zephyr 3.5.0 I2S on nrf52840

ms360 — Fri, 10 Oct 2025 15:51:45 GMT

looking good.

can I try your i2s build?

RE: zephyr 3.5.0 I2S on nrf52840

Elfving — Fri, 10 Oct 2025 11:08:31 GMT

[quote user="ms360"]

Thanks Elfving. That didn't make a difference.

[/quote]

Hahah alright. Sorry about that.

[quote user="ms360"]However my colleague was able to get all four lines working in the ZMK tree. [/quote]

I am a bit surprised though because I believe that did get some wiggling on my side. Are you able to get Blinky working on those pins, using eg this hex?devzone.nordicsemi.com/.../5466.zephyr.hex

Regards,

Elfving

RE: zephyr 3.5.0 I2S on nrf52840

ms360 — Thu, 09 Oct 2025 16:54:28 GMT

Thanks Elfving. That didn't make a difference.

However my colleague was able to get all four lines working in the ZMK tree. I pulled that and ran it on my fresh dev kit and still not seeing it wiggle. I have a brand new v3.0.3 PCA10056 and just double checked those pins and don't see any solder bridges on those pins

RE: zephyr 3.5.0 I2S on nrf52840

Elfving — Thu, 09 Oct 2025 13:36:13 GMT

Trying this myself now I see that there are seemingly some overlapping assignments, not sure how I didn't see this earlier. Are you seeing this on your side as well? And could you try either deleting or moving the spi pins?

Eg. add this:

&spi1 {
    status = "disabled";
};

Regards,

Elfving

RE: zephyr 3.5.0 I2S on nrf52840

ms360 — Wed, 08 Oct 2025 18:30:34 GMT

I just tried this on a fresh dev kit to rule out any hardware damage, and got the same result.

RE: zephyr 3.5.0 I2S on nrf52840

ms360 — Tue, 07 Oct 2025 22:22:25 GMT

I thought I saw an i2s loopback example somewhere but that may have been nrf sdk. Do you have any suggestions of something to try that doesn't require a codec/shield?

RE: zephyr 3.5.0 I2S on nrf52840

ms360 — Tue, 07 Oct 2025 14:21:47 GMT

I thought the same things.
I'm using ncs v3.1.1

RE: zephyr 3.5.0 I2S on nrf52840

Elfving — Tue, 07 Oct 2025 07:42:21 GMT

There are two obvious things that could be at fault here that comes to mind. One would be if you chose pins that were assigned to something else in the HW of the DK, and would maybe need to cut a SB to fix that (you can find these pins in the table underneath the DK). Another would be if you assigned another peripheral to the same pins. I am not seeing neither of this being at fault here.

What NCS version were you using btw?

Regards,

Elfving

RE: zephyr 3.5.0 I2S on nrf52840

ms360 — Mon, 06 Oct 2025 23:29:51 GMT

yeah I just tried with NCS. same result. Only LRCK and SDOUT are wiggling on the logic analyzer. I attached my project.
devzone.nordicsemi.com/.../ncs_5F00_i2s_5F00_test.zip

RE: zephyr 3.5.0 I2S on nrf52840

Elfving — Wed, 01 Oct 2025 13:44:43 GMT

Hi,

[quote user=""]Hi. I have a new project using zephyr 3.5.0 and ZMK, so I don't think NCS SDK is an option.
[/quote]

No if you need that then I guess not. I am not that familiar with ZMK, and since you're not able to use NCS here either I think you might be able to get more support in the Zephyr Discord group. A quick search here shows me that people might've asked there for help with this before.

[quote user=""]

I am trying to configure I2S, and the examples I'm seeing for the above toolchain are inconsistent.
For starters I just want to see MCK, SCK, LRCK and SDOUT on the logic analyzer before managing buffering.
I am obviously not a zephyr pro, I've used it twice before for brief projects.

[/quote]

I also feel forced to mention that using a supported NCS version, and trying the courses in our DevAcademy is a great starting point if you are somewhat new. Though this doesn't really get you what you are trying to do here. We do offer other frameworks like nRF Desktop and CAF, but I guess we haven't gotten to ZMK yet.

[quote user=""]

eg - I try the following, but I only see LRCK and SDOUT on the logic analyzer.
I had MCK working at one point but have lost that configuration with trial and error.

i2s0_default: i2s0_default {

group1 {

psels = <NRF_PSEL(I2S_MCK, 0, 28)>,

<NRF_PSEL(I2S_SCK_M, 0, 30)>,

<NRF_PSEL(I2S_LRCK_M, 0, 29)>,

<NRF_PSEL(I2S_SDOUT, 0, 31)>;

};

[/quote]

When it comes to this problem, are you seeing it on NCS versions as well?

Regards,

Elfving

RE: zephyr 3.5.0 I2S on nrf52840

ms360 — Tue, 30 Sep 2025 23:46:27 GMT

This is my nrf52840dk_nrf52840.overlay
With the above code, SDOUT and LRCLK_M look great, but I cannot see SCK_M or MCK.

/ {

};

&i2c1 {
    status = "okay";
    compatible = "nordic,nrf-twim";
    pinctrl-0 = <&i2c1_default>;    

    tas2110_i2c: tas2110_i2c@48 {
        compatible = "i2c-device";
        reg = <0x48>;
        status = "okay";
    };
};

&i2s0 {
    compatible = "nordic,nrf-i2s";
    status = "okay";
	pinctrl-0 = <&i2s0_default>;
	pinctrl-names = "default";
};

&pinctrl {
    i2c1_default: i2c1_default {
        group1 {
            psels = <NRF_PSEL(TWIM_SDA, 0, 26)>, // P0.26 for SDA
                    <NRF_PSEL(TWIM_SCL, 0, 27)>; // P0.27 for SCL
        };
    };
    i2s0_default: i2s0_default {
        group1 {
            psels = <NRF_PSEL(I2S_MCK, 0, 28)>, 
                    <NRF_PSEL(I2S_SCK_M, 0, 30)>, 
                    <NRF_PSEL(I2S_LRCK_M, 0, 29)>, 
                    <NRF_PSEL(I2S_SDOUT, 0, 31)>;
        };
    };
};