Update doc and example

esp-hal/src/timer/systimer.rs

@@ -173,6 +173,10 @@ impl<'d> SystemTimer<'d> {
 
 impl SystemTimer<'static> {
     /// Split the System Timer into three alarms.
+    ///
+    /// This is a convenience method to create `'static` alarms of the same
+    /// type. You are encouraged to use [Alarm::new] over this very specific
+    /// helper.
     pub fn split<MODE>(self) -> SysTimerAlarms<MODE, Blocking> {
         static CONFIG: Mutex<Cell<Option<Config>>> = Mutex::new(Cell::new(None));
         static mut UNIT0: Option<Unit<'static, 0>> = None;
@@ -193,6 +197,10 @@ impl SystemTimer<'static> {
     }
 
     /// Split the System Timer into three alarms.
+    ///
+    /// This is a convenience method to create `'static` alarms of the same
+    /// type. You are encouraged to use [Alarm::new_async] over this very
+    /// specific helper.
     pub fn split_async<MODE>(self) -> SysTimerAlarms<MODE, Async> {
         static CONFIG: Mutex<Cell<Option<Config>>> = Mutex::new(Cell::new(None));
         static mut UNIT0: Option<Unit<'static, 0>> = None;

examples/src/bin/systimer.rs

@@ -7,7 +7,7 @@
 #![no_std]
 #![no_main]
 
-use core::cell::RefCell;
+use core::cell::{Cell, RefCell};
 
 use critical_section::Mutex;
 use esp_backtrace as _;
@@ -18,11 +18,12 @@ use esp_hal::{
     peripherals::{Interrupt, Peripherals},
     prelude::*,
     system::SystemControl,
-    timer::systimer::{Alarm, Periodic, SystemTimer, Target},
+    timer::systimer::{Alarm, Config, FrozenUnit, Periodic, SystemTimer, Target, Unit},
     Blocking,
 };
 use esp_println::println;
 use fugit::ExtU32;
+use static_cell::StaticCell;
 
 static ALARM0: Mutex<RefCell<Option<Alarm<Periodic, Blocking, 0, 0>>>> =
     Mutex::new(RefCell::new(None));
@@ -40,20 +41,28 @@ fn main() -> ! {
     let systimer = SystemTimer::new(peripherals.SYSTIMER);
     println!("SYSTIMER Current value = {}", SystemTimer::now());
 
-    let alarms = systimer.split();
+    static CONFIG: Mutex<Cell<Option<Config>>> = Mutex::new(Cell::new(None));
+    static UNIT0: StaticCell<Unit<'static, 0>> = StaticCell::new();
+
+    let unit0 = UNIT0.init(systimer.unit0);
+    critical_section::with(|cs| CONFIG.borrow(cs).set(Some(systimer.config)));
+
+    let frozen_unit = FrozenUnit::new(unit0);
+
+    let mut alarm0 = Alarm::new(systimer.comparator0, &frozen_unit, &CONFIG);
+    let mut alarm1 = Alarm::new(systimer.comparator1, &frozen_unit, &CONFIG);
+    let mut alarm2 = Alarm::new(systimer.comparator2, &frozen_unit, &CONFIG);
 
     critical_section::with(|cs| {
-        let mut alarm0 = alarms.alarm0.into_periodic();
+        let mut alarm0 = alarm0.into_periodic();
         alarm0.set_interrupt_handler(systimer_target0);
         alarm0.set_period(1u32.secs());
         alarm0.enable_interrupt(true);
 
-        let mut alarm1 = alarms.alarm1;
         alarm1.set_interrupt_handler(systimer_target1);
         alarm1.set_target(SystemTimer::now() + (SystemTimer::TICKS_PER_SECOND * 2));
         alarm1.enable_interrupt(true);
 
-        let mut alarm2 = alarms.alarm2;
         alarm2.set_interrupt_handler(systimer_target2);
         alarm2.set_target(SystemTimer::now() + (SystemTimer::TICKS_PER_SECOND * 3));
         alarm2.enable_interrupt(true);