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#![no_std]
pub use groundhog::RollingTimer;
use embedded_hal::blocking::delay::{DelayUs, DelayMs};
use core::sync::atomic::{AtomicPtr, Ordering};
use stm32g0xx_hal::{
stm32::{
TIM2,
RCC,
tim2::RegisterBlock as Tim2Rb,
},
};
static TIMER_PTR: AtomicPtr<Tim2Rb> = AtomicPtr::new(core::ptr::null_mut());
pub struct GlobalRollingTimer;
impl GlobalRollingTimer {
pub const fn new() -> Self {
Self
}
pub fn init(timer: TIM2) {
let rcc = unsafe {&*RCC::ptr()};
rcc.apbenr1.modify(|_, w| w.tim2en().set_bit());
rcc.apbrstr1.modify(|_, w| w.tim2rst().set_bit());
rcc.apbrstr1.modify(|_, w| w.tim2rst().clear_bit());
timer.cr1.modify(|_, w| w.cen().clear_bit());
timer.cnt.reset();
timer.psc.write(|w| unsafe { w.psc().bits(63) });
timer.arr.write(|w| unsafe { w.bits(0xFFFFFFFF) });
timer.egr.write(|w| w.ug().set_bit());
timer.cr1.modify(|_, w| w.cen().set_bit().urs().set_bit());
let old_ptr = TIMER_PTR.load(Ordering::SeqCst);
TIMER_PTR.store(TIM2::ptr() as *mut _, Ordering::SeqCst);
debug_assert!(old_ptr == core::ptr::null_mut());
}
}
impl RollingTimer for GlobalRollingTimer {
type Tick = u32;
const TICKS_PER_SECOND: u32 = 1_000_000;
fn get_ticks(&self) -> u32 {
if let Some(t0) = unsafe { TIMER_PTR.load(Ordering::SeqCst).as_ref() } {
t0.cnt.read().bits()
} else {
0
}
}
}
impl DelayUs<u32> for GlobalRollingTimer {
fn delay_us(&mut self, us: u32) {
let start = self.get_ticks();
while self.ticks_since(start) < us { }
}
}
impl DelayMs<u32> for GlobalRollingTimer {
fn delay_ms(&mut self, ms: u32) {
for _ in 0..ms {
self.delay_us(1000)
}
}
}