Cannot build I2S echo application for NRF5340

[TomHe]

Hi, I am a beginner into the embedded audio space, and happened upon this board to use for our university project. Our team's current plan would be to produce audio directly on the board and play it through the headphone jack, but have not found much success with the NRF5340 Audio application, as it has a lot of integration with Bluetooth (which we don't need for now). Right now we just need a simple application that plays a tune on the board.

In my search I have found the I2S echo application, which seems like a simple start for our use case. However, when trying to build the application we encountered the following error:

-- Found BOARD.dts: C:/ncs/v2.6.2/zephyr/boards/arm/nrf5340_audio_dk_nrf5340/nrf5340_audio_dk_nrf5340_cpuapp.dts
-- Found devicetree overlay: boards/nrf5340dk_nrf5340_cpuapp.overlay
devicetree error: pinctrl-names property in /soc/peripheral@50000000/i2s@28000 in C:/ncs/v2.6.2/zephyr/misc/empty_file.c has 1 strings, expected 2 strings

This is our build configuration (all other options left as default):

SDK version:

Any help would be appreciated! Thanks!

[ace.johnny]

 Alexander,

Your informative comments are extremely appreciated.

Part of the difficulty in deciphering the nrf5340_audio application is the stunningly genius method of compensating the clocks to achieve synchronous stereo across disparate devices. It's truly amazing, but incredibly intricate.

I've also spent a good amount of time studying the CS47L63, and I think I understand it fairly well. My original attempts to use the FLLs with only Nordic's hex register values as example were frustrating, so I instead started with SYSCLK using the internal RCO oscillator at 12.288MHz, and then switched source to the bypassed ACLK/MCK directly by skipping FLL1 entirely.

I eventually discovered the FLL functions in cs47l63.c which solved most of my FLL1 woes, and now I feel confident using it with a much more flexible MCK of 6.144MHz to accommodate many more sample rates.

And thank you so much for pointing out my math illiteracy by missing the flooring notation in the frequency equation. What a revelation to finally understand why I kept reaching the wrong value.

Again, your assistance has been invaluable, and I sincerely thank you for taking the time to respond. Kudos.

[Alexander Svensen]

No problem, glad I could help