docs: brief intro to critical-section

Author: duskmoon314

CHANGELOG.md

@@ -17,6 +17,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - Make writing raw bits to a whole register safe if the SVD indicates
   so through the <WriteConstraint> element (see [v0.7.1] too).
 - Remove lint #![deny(const_err)] as it is a hard error in Rust now
+- Add doc of using `critical-section`
 
 ## [v0.26.0] - 2022-10-07
 

src/lib.rs

@@ -185,6 +185,10 @@
 //! let panics = stm32f30x::Peripherals::take().unwrap();
 //! ```
 //!
+//! This method needs an implementation of `critical-section`. You can implement it yourself or
+//! use the implementation provided by the target crate like `cortex-m`, `riscv` and `*-hal` crates.
+//! See more details in the [`critical-section`](https://crates.io/crates/critical-section) crate documentation.
+//!
 //! The singleton property can be *unsafely* bypassed using the `ptr` static method which is
 //! available on all the peripheral types. This method is useful for implementing safe higher
 //! level abstractions.