Module cortex_m_quickstart::examples::_0_minimal

Minimal Cortex-M program

When executed this program will hit the breakpoint set in main.

All Cortex-M programs need to:

• Contain the #![no_main] and #![no_std] attributes. Embedded programs don't use the standard Rust main interface or the Rust standard (std) library.

• Define their entry point using entry! macro.

• Define their panicking behavior, i.e. what happens when panic! is called. The easiest way to define a panicking behavior is to link to a panic handler crate

• Define the HardFault handler using the exception! macro. This handler (function) is called when a hard fault exception is raised by the hardware.

• Define a default handler using the exception! macro. This function will be used to handle all interrupts and exceptions which have not been assigned a specific handler.

#![no_main] // <- IMPORTANT!
#![no_std]

extern crate cortex_m;

#[macro_use(entry, exception)]
extern crate cortex_m_rt as rt;

// makes `panic!` print messages to the host stderr using semihosting
extern crate panic_semihosting;

use cortex_m::asm;
use rt::ExceptionFrame;

// the program entry point is ...
entry!(main);

// ... this never ending function
fn main() -> ! {
    loop {
        asm::bkpt();
    }
}

// define the hard fault handler
exception!(HardFault, hard_fault);

fn hard_fault(ef: &ExceptionFrame) -> ! {
    panic!("HardFault at {:#?}", ef);
}

// define the default exception handler
exception!(*, default_handler);

fn default_handler(irqn: i16) {
    panic!("Unhandled exception (IRQn = {})", irqn);
}