blinky_msg2

examples/rtfm_blinky_msg2.rs

+#![deny(unsafe_code)]
+// #![deny(warnings)]
+#![no_main]
+#![no_std]
+
+use cortex_m::peripheral::DWT;
+use cortex_m_semihosting::hprintln;
+use panic_halt as _;
+use rtfm::cyccnt::{Instant, U32Ext as _};
+use stm32f4xx_hal::stm32;
+
+#[rtfm::app(device = stm32f4xx_hal::stm32, monotonic = rtfm::cyccnt::CYCCNT, peripherals = true)]
+const APP: () = {
+    #[init(schedule = [toggle])]
+    fn init(mut cx: init::Context) {
+        let mut core = cx.core;
+        let mut 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
+
+        // 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));
+
+        cx.schedule
+            .toggle(now + 8_000_000.cycles(), true, device.GPIOA);
+    }
+
+    #[task(schedule = [toggle])]
+    fn toggle(cx: toggle::Context, toggle: bool, gpioa: stm32::GPIOA) {
+        hprintln!("toggle  @ {:?}", Instant::now()).unwrap();
+
+        if toggle {
+            gpioa.bsrr.write(|w| w.bs5().set_bit());
+        } else {
+            gpioa.bsrr.write(|w| w.br5().set_bit());
+        }
+
+        cx.schedule
+            .toggle(cx.scheduled + 8_000_000.cycles(), !toggle, gpioa);
+    }
+
+    extern "C" {
+        fn EXTI0();
+    }
+};