Add RTC timer for stm32f4

embassy-stm32f4-examples/src/bin/rtc_async.rs

@@ -0,0 +1,65 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+#[path = "../example_common.rs"]
+mod example_common;
+use example_common::*;
+
+use cortex_m_rt::entry;
+use defmt::panic;
+use embassy::executor::{task, Executor};
+use embassy::time::{Duration, Timer};
+use embassy::util::Forever;
+use embassy_stm32f4::{interrupt, pac, rtc};
+use stm32f4xx_hal::prelude::*;
+
+#[task]
+async fn run1() {
+    loop {
+        info!("BIG INFREQUENT TICK");
+        Timer::after(Duration::from_ticks(32768 * 2)).await;
+    }
+}
+
+#[task]
+async fn run2() {
+    loop {
+        info!("tick");
+        Timer::after(Duration::from_ticks(13000)).await;
+    }
+}
+
+static RTC: Forever<rtc::RTC<pac::TIM2>> = Forever::new();
+static ALARM: Forever<rtc::Alarm<pac::TIM2>> = Forever::new();
+static EXECUTOR: Forever<Executor> = Forever::new();
+
+#[entry]
+fn main() -> ! {
+    info!("Hello World!");
+
+    let p = unwrap!(pac::Peripherals::take());
+
+    p.RCC.ahb1enr.modify(|_, w| w.dma1en().enabled());
+    let rcc = p.RCC.constrain();
+    let clocks = rcc.cfgr.freeze();
+
+    p.DBGMCU.cr.modify(|_, w| {
+        w.dbg_sleep().set_bit();
+        w.dbg_standby().set_bit();
+        w.dbg_stop().set_bit()
+    });
+
+    let rtc = RTC.put(rtc::RTC::new(p.TIM2, interrupt::take!(TIM2), clocks));
+    rtc.start();
+
+    unsafe { embassy::time::set_clock(rtc) };
+
+    let alarm = ALARM.put(rtc.alarm1());
+    let executor = EXECUTOR.put(Executor::new());
+    executor.set_alarm(alarm);
+    executor.run(|spawner| {
+        unwrap!(spawner.spawn(run1()));
+        unwrap!(spawner.spawn(run2()));
+    });
+}