runtime: improve timers on nrf, and samd chips #1870
Merged
Conversation
This file contains 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
This commit improves the timers on various microcontrollers to better deal with counter wraparound. The result is a reduction in RAM size of around 12 bytes and a small effect (sometimes positive, sometimes negative) on flash consumption. But perhaps more importantly: getting the current time is now interrupt-safe (it previously could result in a race condition) and the timer will now be correct when the timer isn't retrieved for a long duration. Before this commit, a call to `time.Now` more than 8 minutes after the previous call could result in an incorrect time. For more details, see: https://www.eevblog.com/forum/microcontrollers/correct-timing-by-timer-overflow-count/msg749617/#msg749617
|
This is a very clever technique indeed. Now merging, good ⌚ @aykevl |
This was referenced Feb 9, 2022
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
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Outdated suggestions cannot be applied.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.
This commit improves the timers on various microcontrollers to better
deal with counter wraparound. The result is a reduction in RAM size of
around 12 bytes and a small effect (sometimes positive, sometimes
negative) on flash consumption. But perhaps more importantly: getting
the current time is now interrupt-safe (it previously could result in a
race condition) and the timer will now be correct when the timer isn't
retrieved for a long duration. Before this commit, a call to
time.Nowmore than 8 minutes after the previous call could result in an incorrect
time.
For more details, see:
https://www.eevblog.com/forum/microcontrollers/correct-timing-by-timer-overflow-count/msg749617/#msg749617
I have made this improvement while working on better documentation for adding new chip support to TinyGo, in particular how to add support for keeping time and for sleeping.
CC @kenbell and @ofauchon: this might be of interest.