cortex-m-quickstart 0.1.2

//! Sends "Hello, world!" through the ITM port 0
//!
//! **IMPORTANT** Not all Cortex-M chips support ITM. You'll have to connect the
//! microcontroller's SWO pin to the SWD interface. Note that some development
//! boards don't provide this option.
//!
//! ITM is much faster than semihosting. Like 4 orders of magnitude or so.
//!
//! You'll need [`itmdump`] to receive the message on the host plus you'll need
//! to uncomment OpenOCD's ITM support in `.gdbinit`.
//!
//! [`itmdump`]: https://docs.rs/itm/0.1.1/itm/

#![feature(used)]
#![no_std]

#[macro_use]
extern crate cortex_m;
extern crate cortex_m_rt;

use cortex_m::{asm, interrupt, peripheral};

fn main() {
    interrupt::free(
        |cs| {
            let itm = peripheral::ITM.borrow(&cs);

            iprintln!(&itm.stim[0], "Hello, world!");
        },
    );
}

// As we are not using interrupts, we just register a dummy catch all handler
#[allow(dead_code)]
#[used]
#[link_section = ".rodata.interrupts"]
static INTERRUPTS: [extern "C" fn(); 240] = [default_handler; 240];

extern "C" fn default_handler() {
    asm::bkpt();
}