I2S - Unable to generate MCK and SCK on nRF 52 board

RE: I2S - Unable to generate MCK and SCK on nRF 52 board

Morten — Thu, 16 Mar 2017 12:31:46 GMT

Hi, I had what I think is the same problem with a Knowles microphone(SPH0645LM4H-B). A similar question(duplicate?) is located here

And I think that we are all struggling with these two conditions from the product specification:

When configuring these registers, the user is responsible for fulfilling the following requirements:

  1. SCK frequency can never exceed the MCK frequency, which can be formulated as:

      CONFIG.RATIO >= 2 * CONFIG.SWIDTH

  2. The MCK/LRCK ratio shall be a multiple of 2 * CONFIG.SWIDTH, which can be formulated as:

      Integer = (CONFIG.RATIO / (2 * CONFIG.SWIDTH))

We all have a microphone that has a bit width of 24, that excludes all ratio settings except for 48,96,192,384. The SCL/LRCLK is required from the datasheet to be 64, but the only ratio from these settings are 48.

Please correct me if I am wrong, I would really like to get my microphone up and running.

RE: I2S - Unable to generate MCK and SCK on nRF 52 board

Johan — Thu, 07 Apr 2016 14:33:32 GMT

I think you would probably want to use some other GPIO pins than 0 and 1 since they are used by the crystal on the NRF52 DK board. Check the backside of the board to see which pins are already in use by the board.

RE: I2S - Unable to generate MCK and SCK on nRF 52 board

Shashi — Thu, 11 Feb 2016 20:47:03 GMT

Hi Aryan,

Thank you for looking in to this.

Yes. I've spent a lot of time trying to get this working on nRF52. At this point, is there anything you can do to help resolve this issue? I'm thinking of giving up on nRF52. Do you have any ETA for the 1.0 version of nRF52 SDK and the example/driver for i2S? Does the above code look right? Do I have to use the low-level API to work with i2S?

Thanks again.

Cheers, Shashi

RE: I2S - Unable to generate MCK and SCK on nRF 52 board

Susheel Nuguru — Thu, 11 Feb 2016 07:28:18 GMT

Shashi, do you still have this problem?