systick: Added example

Author: h2obrain

Cargo.toml

@@ -134,3 +134,7 @@ required-features = ["rt", "stm32f407"]
 [[example]]
 name = "qei"
 required-features = ["rt", "stm32f411"]
+
+[[example]]
+name = "systick-blinky"
+required-features = ["rt", "stm32f429"]

examples/systick-blinky.rs

@@ -0,0 +1,50 @@
+#![deny(unsafe_code)]
+#![no_main]
+#![no_std]
+
+// Halt on panic
+#[allow(unused_extern_crates)] // NOTE(allow) bug rust-lang/rust#53964
+extern crate panic_halt; // panic handler
+
+use cortex_m;
+use cortex_m_rt::entry;
+use stm32f4xx_hal as hal;
+
+use crate::hal::{prelude::*, stm32, systick::SysTickTime};
+
+#[entry]
+fn main() -> ! {
+    if let (Some(dp), Some(cp)) = (
+        stm32::Peripherals::take(),
+        cortex_m::peripheral::Peripherals::take(),
+    ) {
+        // Set up the LEDs. On the STM32F429I-DISC[O1] they are connected to pin PG13/14.
+        let gpiog = dp.GPIOG.split();
+        let mut led1 = gpiog.pg13.into_push_pull_output();
+        let mut led2 = gpiog.pg14.into_push_pull_output();
+
+        // Set up the system clock. We want to run at 48MHz for this one.
+        let rcc = dp.RCC.constrain();
+        let clocks = rcc.cfgr.sysclk(48.mhz()).freeze();
+
+        // Create a delay abstraction based on SysTick
+        let mut systime = cp.SYST.to_systemtime(1000.hz(), clocks);
+
+        loop {
+            // On for 1s, off for 1s.
+            led1.set_high().unwrap();
+            led2.set_low().unwrap();
+            systime.delay_ms(1000_u32);
+            led1.set_low().unwrap();
+            led2.set_high().unwrap();
+            systime.delay_ms(1000_u32);
+            // Also you can get the current time
+            let _t = systime.s(); // in seconds as double
+            let _t = systime.ms(); // in milliseconds as u64
+            let _t = systime.us(); // in microseconds as u64
+            let _t = systime.ns(); // in nanoseconds as u64
+        }
+    }
+
+    loop {}
+}