From 15f9ca67e478c792792b8dac8ab18c9eb8fc2437 Mon Sep 17 00:00:00 2001
From: Maxime Borges <contact@maximeborg.es>
Date: Fri, 28 Jan 2022 17:57:46 +0100
Subject: [PATCH 1/2] example/timer: Clear the interrupt flag

---
 examples/timer.rs | 21 ++++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/examples/timer.rs b/examples/timer.rs
index 10677f0..85ca39d 100644
--- a/examples/timer.rs
+++ b/examples/timer.rs
@@ -7,18 +7,23 @@
 extern crate panic_semihosting;
 
 use core::fmt::Write;
+use core::cell::{RefCell};
 
+use cortex_m::interrupt::{free, Mutex};
 use cortex_m_rt::entry;
 use cortex_m_semihosting::hio;
 
 use cortex_m::peripheral::NVIC;
 
 use stm32f7xx_hal::{
-    interrupt, pac,
+    interrupt,
+    pac::{self, TIM2},
     prelude::*,
     timer::{Event, Timer},
 };
 
+static TIMER: Mutex<RefCell<Option<Timer<TIM2>>>> = Mutex::new(RefCell::new(None));
+
 #[entry]
 fn main() -> ! {
     let mut hstdout = hio::hstdout().unwrap();
@@ -29,17 +34,27 @@ fn main() -> ! {
     let mut rcc = dp.RCC.constrain();
     let clocks = rcc.cfgr.freeze();
 
+    let mut timer = Timer::tim2(dp.TIM2, 1.Hz(), clocks, &mut rcc.apb1);
+    timer.listen(Event::TimeOut);
+
+    // Save information needed by the interrupt handler to the global variable
+    free(|cs| {
+        TIMER.borrow(cs).replace(Some(timer));
+    });
+
     unsafe {
         NVIC::unmask(pac::Interrupt::TIM2);
     }
-    let mut timer = Timer::tim2(dp.TIM2, 1.Hz(), clocks, &mut rcc.apb1);
-    timer.listen(Event::TimeOut);
 
     loop {}
 }
 
 #[interrupt]
 fn TIM2() {
+    free(|cs| {
+        TIMER.borrow(cs).borrow_mut().as_mut().unwrap().clear_interrupt(Event::TimeOut)
+    });
+
     let mut hstdout = hio::hstdout().unwrap();
     writeln!(hstdout, "TIM2 intr!").unwrap();
 }

From 96285139ae5bb6adb47681235e70c7086369fe8b Mon Sep 17 00:00:00 2001
From: Maxime Borges <contact@maximeborg.es>
Date: Tue, 8 Feb 2022 18:05:53 +0100
Subject: [PATCH 2/2] Fix formating

---
 examples/timer.rs | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/examples/timer.rs b/examples/timer.rs
index 85ca39d..b22e2b3 100644
--- a/examples/timer.rs
+++ b/examples/timer.rs
@@ -6,8 +6,8 @@
 
 extern crate panic_semihosting;
 
+use core::cell::RefCell;
 use core::fmt::Write;
-use core::cell::{RefCell};
 
 use cortex_m::interrupt::{free, Mutex};
 use cortex_m_rt::entry;
@@ -52,7 +52,12 @@ fn main() -> ! {
 #[interrupt]
 fn TIM2() {
     free(|cs| {
-        TIMER.borrow(cs).borrow_mut().as_mut().unwrap().clear_interrupt(Event::TimeOut)
+        TIMER
+            .borrow(cs)
+            .borrow_mut()
+            .as_mut()
+            .unwrap()
+            .clear_interrupt(Event::TimeOut)
     });
 
     let mut hstdout = hio::hstdout().unwrap();