rtic/examples/periodic.rs

//! examples/periodic.rs

#![deny(unsafe_code)]
#![deny(warnings)]
#![no_main]
#![no_std]

use cortex_m_semihosting::hprintln;
use panic_semihosting as _;
use rtic::cyccnt::{Instant, U32Ext};

const PERIOD: u32 = 8_000_000;

// NOTE: does NOT work on QEMU!
#[rtic::app(device = lm3s6965, monotonic = rtic::cyccnt::CYCCNT)]
mod app {

    #[init]
    fn init(cx: init::Context) -> init::LateResources {
        // omitted: initialization of `CYCCNT`

        foo::schedule(cx.start + PERIOD.cycles()).unwrap();

        init::LateResources {}
    }

    #[task]
    fn foo(cx: foo::Context) {
        let now = Instant::now();
        hprintln!("foo(scheduled = {:?}, now = {:?})", cx.scheduled, now).unwrap();

        foo::schedule(cx.scheduled + PERIOD.cycles()).unwrap();
    }

    // RTIC requires that unused interrupts are declared in an extern block when
    // using software tasks; these free interrupts will be used to dispatch the
    // software tasks.
    extern "C" {
        fn SSI0();
    }
}