nrf/i2s: allow master mode without MCK pin #4843
Open
+3
−2
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Outputting the generated master clock is optional as per Nordic docs: "The MCK signal can be routed to an output pin (specified in PSEL.MCK) to supply external I2S devices that require the MCK to be supplied from the outside." [1] Some I2S DACs, such as MAX98357A, don't require a master clock input so it can be left disconnected. nRF Connect SDK supports this. [1] https://docs.nordicsemi.com/bundle/ps_nrf52833/page/i2s.html [2] https://www.analog.com/media/en/technical-documentation/data-sheets/max98357a-max98357b.pdf
lulf
reviewed
Nov 14, 2025
Member
lulf
left a comment
lulf
left a comment
There was a problem hiding this comment.
I think what I'd prefer is that you rename the current to fn new_master_with_mck(), then remove mck from new_master(), and have both call into a new_inner or something that is not public.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Outputting the generated master clock is optional as per Nordic docs: "The MCK signal can be routed to an output pin (specified in PSEL.MCK) to supply external I2S devices that require the MCK to be supplied from the outside." [1]
Some I2S DACs, such as MAX98357A, don't require a master clock input so it can be left disconnected. nRF Connect SDK supports this.
[1] https://docs.nordicsemi.com/bundle/ps_nrf52833/page/i2s.html
[2] https://www.analog.com/media/en/technical-documentation/data-sheets/max98357a-max98357b.pdf
Not sure whether this API is ideal as it requires the caller to write
None::<Peri<'static, AnyPin>>. Maybe these functions should be changed to take AnyPin like some other APIs?