changelog and migration

esp-hal/CHANGELOG.md

@@ -11,14 +11,20 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - ESP32-S3: Added SDMMC signals (#2556)
 - `dma::{Channel, ChannelRx, ChannelTx}::set_priority` for GDMA devices (#2403)
+- `SystemTimer::set_unit_count` & `SystemTimer::configure_unit` (#2576)
 
 ### Changed
 
+- `SystemTimer` no longer uses peripheral ref (#2576)
+- `SystemTimer::now` has been renamed `SystemTimer::unit_count(Unit)` (#2576)
+
 ### Fixed
 
 ### Removed
 
 - The `configure` and `configure_for_async` DMA channel functions has been removed (#2403)
+- `SysTimerAlarms` has been removed, alarms are now part of the `SystemTimer` struct (#2576)
+- `FrozenUnit`, `AnyUnit`, `SpecificUnit`, `SpecificComparator`, `AnyComparator` have been removed from `systimer` (#2576)
 
 ## [0.22.0] - 2024-11-20
 

esp-hal/MIGRATING-0.22.md

@@ -15,3 +15,21 @@
 -.with_dma(dma_channel.configure(false, DmaPriority::Priority0));
 +.with_dma(dma_channel);
 ```
+
+## Timer changes
+
+The low level timers, `SystemTimer` and `TimerGroup` are now "dumb". They contain no logic for operating modes or trait implementations (except the low level `Timer` trait).
+
+### SystemTimer
+
+```diff
+let systimer = SystemTimer::new(peripherals.SYSTIMER);
+- static UNIT0: StaticCell<SpecificUnit<'static, 0>> = StaticCell::new();
+- let unit0 = UNIT0.init(systimer.unit0);
+- let frozen_unit = FrozenUnit::new(unit0);
+- let alarm0 = Alarm::new(systimer.comparator0, &frozen_unit);
+- alarm0.set_period(1u32.secs());
++ let alarm0 = systimer.alarm0;
++ let mut timer = PeriodicTimer::new(alarm0);
++ timer.start(1u64.secs());
+```