Skip to content

Bug fix: race condition in I2C cr1 read-modify-write #662

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
burrbull merged 3 commits into from
Jul 3, 2023
Merged

Bug fix: race condition in I2C cr1 read-modify-write #662

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
5fc1836
Bug fix: race condition in I2C cr1 read-modify-write
zyma98 Jul 2, 2023
2b27903
Merge branch 'stm32-rs:master' into master
zyma98 Jul 2, 2023
7cd25a5
A better fix and Change log update.
zyma98 Jul 2, 2023
File filter

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
2 changes: 2 additions & 0 deletions CHANGELOG.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -11,8 +11,10 @@ and this project adheres to [Semantic Versioning](http://semver.org/).

- move gpio, dma impls, adc pins in subdir, remove unused `From` impls [#658] [#664]
- Bump `embedded-hal` to `1.0.0-alpha.10`. See [their changelog][embedded-hal-1.0.0-alpha.10] for further details. Note that this included breaking changes to the previous alpha APIs. [#663]
- Fix race condition in sending start condition in I2C. [#662]

[#658]: https://github.com/stm32-rs/stm32f4xx-hal/pull/658
[#662]: https://github.com/stm32-rs/stm32f4xx-hal/pull/662
[#663]: https://github.com/stm32-rs/stm32f4xx-hal/pull/663
[#664]: https://github.com/stm32-rs/stm32f4xx-hal/pull/664
[embedded-hal-1.0.0-alpha.10]: https://github.com/rust-embedded/embedded-hal/blob/v1.0.0-alpha.10/embedded-hal/CHANGELOG.md
Expand Down
9 changes: 7 additions & 2 deletions src/i2c/dma.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -421,9 +421,14 @@ where

fn send_start(&mut self, read: bool) -> Result<(), super::Error> {
let i2c = &self.hal_i2c.i2c;
i2c.cr1.modify(|_, w| w.start().set_bit());

// Make sure the ack and start bit is set together in a single
// read-modify-write operation to avoid race condition.
// See PR: https://github.com/stm32-rs/stm32f4xx-hal/pull/662
if read {
i2c.cr1.modify(|_, w| w.ack().set_bit());
i2c.cr1.modify(|_, w| w.ack().set_bit().start().set_bit());
} else {
i2c.cr1.modify(|_, w| w.start().set_bit());
}

// Wait until START condition was generated
Expand Down