added rtt_rtic_blinky, rtt_rtic_hello

examples/rtt_rtic_blinky.rs

+#![deny(unsafe_code)]
+#![deny(warnings)]
+#![no_main]
+#![no_std]
+
+use cortex_m::peripheral::DWT;
+use panic_rtt_target as _;
+use rtic::cyccnt::{Instant, U32Ext as _};
+use rtt_target::{rprintln, rtt_init_print};
+use stm32f4xx_hal::stm32;
+
+#[rtic::app(device = stm32f4xx_hal::stm32, monotonic = rtic::cyccnt::CYCCNT, peripherals = true)]
+const APP: () = {
+    struct Resources {
+        // late resources
+        GPIOA: stm32::GPIOA,
+    }
+    #[init(schedule = [toggle])]
+    fn init(cx: init::Context) -> init::LateResources {
+        rtt_init_print!();
+        rprintln!("init");
+
+        let mut core = cx.core;
+        let device = cx.device;
+
+        // Initialize (enable) the monotonic timer (CYCCNT)
+        core.DCB.enable_trace();
+        // required on Cortex-M7 devices that software lock the DWT (e.g. STM32F7)
+        DWT::unlock();
+        core.DWT.enable_cycle_counter();
+
+        // semantically, the monotonic timer is frozen at time "zero" during `init`
+        // NOTE do *not* call `Instant::now` in this context; it will return a nonsense value
+        let now = cx.start; // the start time of the system
+
+        // Schedule `toggle` to run 8e6 cycles (clock cycles) in the future
+        cx.schedule.toggle(now + 8_000_000.cycles()).unwrap();
+
+        // power on GPIOA, RM0368 6.3.11
+        device.RCC.ahb1enr.modify(|_, w| w.gpioaen().set_bit());
+        // configure PA5 as output, RM0368 8.4.1
+        device.GPIOA.moder.modify(|_, w| w.moder5().bits(1));
+
+        // pass on late resources
+        init::LateResources {
+            GPIOA: device.GPIOA,
+        }
+    }
+
+    #[idle]
+    fn idle(_cx: idle::Context) -> ! {
+        rprintln!("idle");
+        loop {
+            continue;
+        }
+    }
+
+    #[task(resources = [GPIOA], schedule = [toggle])]
+    fn toggle(cx: toggle::Context) {
+        static mut TOGGLE: bool = false;
+        rprintln!("toggle  @ {:?}", Instant::now());
+
+        if *TOGGLE {
+            cx.resources.GPIOA.bsrr.write(|w| w.bs5().set_bit());
+        } else {
+            cx.resources.GPIOA.bsrr.write(|w| w.br5().set_bit());
+        }
+
+        *TOGGLE = !*TOGGLE;
+        cx.schedule
+            .toggle(cx.scheduled + 8_000_000.cycles())
+            .unwrap();
+    }
+
+    extern "C" {
+        fn EXTI0();
+    }
+};

examples/rtt_rtic_hello.rs

+// cargo run --example rtt_rtic_hello
+
+#![no_main]
+#![no_std]
+
+use panic_halt as _;
+use rtt_target::{rprintln, rtt_init_print};
+use stm32f4;
+
+#[rtic::app(device = stm32f4)]
+const APP: () = {
+    #[init]
+    fn init(_cx: init::Context) {
+        rtt_init_print!();
+        for i in 0..11 {
+            rprintln!("RTIC Says Hello, world {}!!", i);
+        }
+    }
+
+    #[idle]
+    fn idle(_cx: idle::Context) -> ! {
+        rprintln!("lets get lazy");
+        loop {
+            continue;
+        }
+    }
+};