Merge #741

741: Docs 2 r=korken89 a=datdenkikniet

Working on the migration guide and other docs

TODO:
- [x] Migration guide
- [x] Hardcoded examples should link to example code that is tested (this was already done, AFAICT)
- [x] Address #699 
- [x] Discuss: should we remove references to non-v2, apart from the migration guide and link to the book for v1? (Off-github conclusion: yes)
- [x] RTIC {vs,and} Embassy (important: distinction between embassy runtime & HALs)
- [x] More descriptive docs on how to implement & PR implementations of `Monotonic` to `rtic-monotonics` 


Co-authored-by: datdenkikniet <jcdra1@gmail.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/book/en/src/migration_v1_v2/monotonics.md b/book/en/src/migration_v1_v2/monotonics.md
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+# Migrating to `rtic-monotonics`
+
+In previous versions of `rtic`, monotonics were an integral, tightly coupled part of the `#[rtic::app]`. In this new version, [`rtic-monotonics`] provides them in a more decoupled way.
+
+The `#[monotonic]` attribute is no longer used. Instead, you use a `create_X_token` from [`rtic-monotonics`]. An invocation of this macro returns an interrupt registration token, which can be used to construct an instance of your desired monotonic.
+
+`spawn_after` and `spawn_at` are no longer available. Instead, you use the async functions `delay` and `delay_until` provided by ipmlementations of the `rtic_time::Monotonic` trait, available through [`rtic-monotonics`].
+
+Check out the [code example](./complete_example.md) for an overview of the required changes.
+
+For more information on current monotonic implementations, see [the `rtic-monotonics` documentation](https://docs.rs/rtic-monotonics), and [the examples](https://github.com/rtic-rs/rtic/tree/master/examples).
+
+[`rtic-monotonics`]: ghttps://github.com/rtic/rtic-monotonics
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