I2S, or SPI Compatibility with PCM Short, and Long Synch frames

[Beshoy]

Hello 
I'm developing a project that would communicate with a cellular module using AT-Commands, and voice data using PCM, these cellular modules are always using PCM Short, and Long Synch frames to send, and receive audio, here I'm using NRF54L15 to interface with the cellular module.
the questions are:
1 - is I2S peripheral compatible with PCM Short, or Long Synch frames. as I've read documentation, and I cannot find that there's configuration that has PCM Short, or Long Synch frames. or is there any hack to make them compatible with each other?

2 - Can I make SPI peripheral communicate with PCM directly or, there's hardware limitations?

[Håkon Alseth]

Hi,

 

The I2S peripheral is similar as for the former nRF52- and nRF53-series devices, meaning it supports:

* Standard I2S (data starts one SCK after the LRCK edge) and Aligned/left-justified (data starts on the LRCK edge).
* A 50% duty-cycle LRCK with left/right channel semantics.
* 8/16/24-bit sample widths and master or slave operation.

1 - is I2S peripheral compatible with PCM Short, or Long Synch frames. as I've read documentation, and I cannot find that there's configuration that has PCM Short, or Long Synch frames. or is there any hack to make them compatible with each other?

This is not supported directly in nRF54L15.

2 - Can I make SPI peripheral communicate with PCM directly or, there's hardware limitations?

I would recommend that you rather look into the nRF54LM20, which has a TDM peripheral:

https://docs.nordicsemi.com/r/bundle/ps_nrf54lm20a/page/tdm.html

 

This can potentially fit your needs.

Another option is to check with the external module vendor to hear if they support I2S mode on that device.

 

Kind regards,

Håkon