A simple library for context-switching on ARM Cortex-M ( 0, 0+, 3, 4, 4F ) micro-processors

Supports pre-emptive, priority based switching

This project is meant for learning and should be used only at the user's risk. For practical and mature rust alternatives, see Awesome Embedded Rust

Processor support:

• Cortex-M0
• Cortex-M0+
• Cortex-M3
• Cortex-M4
• Cortex-M4F

Features:

• Preemptive, priority-based switching
• Efficient sleep
• Accept stack memory area as a vec (arrayvec?, smallvec?) instead of &[]
• Non-privileged mode
• Mutex implementation aware of thread scheduling

The example_crates folder contains crates showing how to use cortexm-threads for different boards.

Available examples:

• stm32f3 - 2 threads with one thread running an LED roulette, and the other periodically printing magnetometer readings. Currently compiles for target thumbv7m-none-eabi instead of thumbv7em-none-eabihf. See Roadmap#1
• microbit - 2 threads printing messages with co-operative context switching
• qemu-m4 - (set up to run on qemu) 2 threads printing messages via semi-hosting. Run cargo run from example_crates/qemu-m4 directory to see it running. You must have qemu-system-arm on the system PATH.

Sample:

#![no_std]
#![no_main]
extern crate panic_semihosting;
use cortex_m::peripheral::syst::SystClkSource;
use cortex_m_rt::{entry, exception};
use cortex_m_semihosting::{hprintln};
use cortexm_threads::{init, create_thread, create_thread_with_config, sleep};
#[entry]
fn main() -> ! {
	let cp = cortex_m::Peripherals::take().unwrap();
	let mut syst = cp.SYST;
	syst.set_clock_source(SystClkSource::Core);
	syst.set_reload(80_000);
	syst.enable_counter();
	syst.enable_interrupt();
	let mut stack1 = [0xDEADBEEF; 512];
	let mut stack2 = [0xDEADBEEF; 512];
	let _ = create_thread(
		&mut stack1, 
		|| {
			loop {
				let _ = hprintln!("in task 1 !!");
				sleep(50); // sleep for 50 ticks
			}
		});
	let _ = create_thread_with_config(
		&mut stack2, 
		|| {
			loop {
				let _ = hprintln!("in task 2 !!");
				sleep(30); // sleep for 30 ticks
			}
		},
		0x01, // priority, higher numeric value means higher priority
		true  // privileged thread
		);
    init();
}

See LICENSE.md