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//! An application with one task
#![deny(unsafe_code)]
#![deny(warnings)]
#![feature(proc_macro)]
#![no_std]
extern crate cortex_m;
extern crate cortex_m_rtfm as rtfm;
extern crate stm32f103xx;
use cortex_m::peripheral::syst::SystClkSource;
use rtfm::{app, Threshold};
use stm32f103xx::GPIOC;
app! {
device: stm32f103xx,
// Here data resources are declared
//
// Data resources are static variables that are safe to share across tasks
resources: {
// Declaration of resources looks exactly like declaration of static
// variables
static ON: bool = false;
},
// Here tasks are declared
//
// Each task corresponds to an interrupt or an exception. Every time the
// interrupt or exception becomes *pending* the corresponding task handler
// will be executed.
tasks: {
// Here we declare that we'll use the SYS_TICK exception as a task
SYS_TICK: {
// Path to the task handler
path: sys_tick,
// These are the resources this task has access to.
//
// The resources listed here must also appear in `app.resources`
resources: [ON],
},
}
}
fn init(mut p: init::Peripherals, r: init::Resources) {
// `init` can modify all the `resources` declared in `app!`
r.ON;
// power on GPIOC
p.device.RCC.apb2enr.modify(|_, w| w.iopcen().enabled());
// configure PC13 as output
p.device.GPIOC.bsrr.write(|w| w.bs13().set());
p.device
.GPIOC
.crh
.modify(|_, w| w.mode13().output().cnf13().push());
// configure the system timer to generate one interrupt every second
p.core.SYST.set_clock_source(SystClkSource::Core);
p.core.SYST.set_reload(8_000_000); // 1s
p.core.SYST.enable_interrupt();
p.core.SYST.enable_counter();
}
fn idle() -> ! {
loop {
rtfm::wfi();
}
}
// This is the task handler of the SYS_TICK exception
//
// `_t` is the preemption threshold token. We won't use it in this program.
//
// `r` is the set of resources this task has access to. `SYS_TICK::Resources`
// has one field per resource declared in `app!`.
#[allow(unsafe_code)]
fn sys_tick(_t: &mut Threshold, mut r: SYS_TICK::Resources) {
// toggle state
*r.ON = !*r.ON;
if *r.ON {
// set the pin PC13 high
// NOTE(unsafe) atomic write to a stateless register
unsafe {
(*GPIOC::ptr()).bsrr.write(|w| w.bs13().set());
}
} else {
// set the pin PC13 low
// NOTE(unsafe) atomic write to a stateless register
unsafe {
(*GPIOC::ptr()).bsrr.write(|w| w.br13().reset());
}
}
}
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