rtic/examples/late.rs

//! examples/late.rs

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

extern crate panic_semihosting;

use cortex_m_semihosting::debug;
use heapless::{
    consts::*,
    spsc::{Consumer, Producer, Queue},
};
use lm3s6965::Interrupt;
use rtfm::app;

macro_rules! println {
    ($($tt:tt)*) => {
        if let Ok(mut stdout) = cortex_m_semihosting::hio::hstdout() {
            use core::fmt::Write;

            writeln!(stdout, $($tt)*).ok();
        }
    };
}

#[app(device = lm3s6965)]
const APP: () = {
    // Late resources
    static mut P: Producer<'static, u32, U4> = ();
    static mut C: Consumer<'static, u32, U4> = ();

    #[init]
    fn init() {
        // NOTE: we use `Option` here to work around the lack of
        // a stable `const` constructor
        static mut Q: Option<Queue<u32, U4>> = None;

        *Q = Some(Queue::new());
        let (p, c) = Q.as_mut().unwrap().split();

        // Initialization of late resources
        P = p;
        C = c;
    }

    #[idle(resources = [C])]
    fn idle() -> ! {
        loop {
            if let Some(byte) = resources.C.dequeue() {
                println!("received message: {}", byte);

                debug::exit(debug::EXIT_SUCCESS);
            } else {
                rtfm::pend(Interrupt::UART0);
            }
        }
    }

    #[interrupt(resources = [P])]
    fn UART0() {
        resources.P.enqueue(42).unwrap();
    }
};