cpu/sam0_common: fix DAC on SAM D5x/E5x#21548
Merged
crasbe merged 2 commits intoRIOT-OS:masterfrom Jun 11, 2025
Merged
Conversation
github-actions
bot
added
Platform: ARM
benpicco
added
the
CI: ready for build
crasbe
added
the
Type: bug
crasbe
reviewed
Jun 10, 2025
crasbe
approved these changes
Jun 11, 2025
github-merge-queue
bot
removed this pull request from the merge queue due to failed status checks
Using the external reference produces no output when no voltage is connected, which makes for a confusing non-functional DAC on the eval board.
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
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
5 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Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be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.
Contribution description
When writing data too quickly on SAM E54, the DAC driver would hang on
while (DAC->SYNCBUSY.reg & mask) {}.The errata sheet suggests to check for
INTFLAG.EMPTYinstead when using internal reference, so just do that.Also use the internal voltage reference by default on
same54-xproto avoid seeing no output at all when using the external reference (and not connecting it to Vref, which is a pretty obscure thing to do).We only get a 1V amplitude, but that's still better than 0V.
Testing procedure
tests/drivers/dac_ddsproduces a neat sine wave for 2s withsine 440 2.Verified this both on
same54-xproandsamd21-xproto avoid introducing a regression there.Issues/PRs references