Add timer example

Author: david-sawatzke

examples/blinky_timer.rs

@@ -0,0 +1,40 @@
+#![no_main]
+#![no_std]
+
+use panic_halt;
+
+use stm32f0xx_hal as hal;
+
+use crate::hal::prelude::*;
+use crate::hal::stm32;
+use crate::hal::time::*;
+use crate::hal::timers::*;
+
+use cortex_m_rt::entry;
+use nb::block;
+
+#[entry]
+fn main() -> ! {
+    if let Some(p) = stm32::Peripherals::take() {
+        let gpioa = p.GPIOA.split();
+        /* (Re-)configure PA1 as output */
+        let mut led = gpioa.pa1.into_push_pull_output();
+
+        /* Constrain clocking registers */
+        let rcc = p.RCC.constrain();
+
+        /* Configure clock to 8 MHz (i.e. the default) and freeze it */
+        let clocks = rcc.cfgr.sysclk(8.mhz()).freeze();
+
+        let mut timer = Timer::tim1(p.TIM1, Hertz(1), clocks);
+
+        loop {
+            led.toggle();
+            block!(timer.wait()).ok();
+        }
+    }
+
+    loop {
+        continue;
+    }
+}