//! Delays.
/// Nanoseconds per microsecond
const NANOS_PER_MICRO: u32 = 1_000;
/// Nanoseconds per millisecond
const NANOS_PER_MILLI: u32 = 1_000_000;
/// Delay with up to nanosecond precision.
pub trait DelayNs {
/// Pauses execution for at minimum `ns` nanoseconds. Pause can be longer
/// if the implementation requires it due to precision/timing issues.
fn delay_ns(&mut self, ns: u32);
/// Pauses execution for at minimum `us` microseconds. Pause can be longer
/// if the implementation requires it due to precision/timing issues.
fn delay_us(&mut self, mut us: u32) {
const MAX_MICROS: u32 = u32::MAX / NANOS_PER_MICRO;
// Avoid potential overflow if micro -> nano conversion is too large
while us > MAX_MICROS {
us -= MAX_MICROS;
self.delay_ns(MAX_MICROS * NANOS_PER_MICRO);
}
self.delay_ns(us * NANOS_PER_MICRO);
}
/// Pauses execution for at minimum `ms` milliseconds. Pause can be longer
/// if the implementation requires it due to precision/timing issues.
#[inline]
fn delay_ms(&mut self, mut ms: u32) {
const MAX_MILLIS: u32 = u32::MAX / NANOS_PER_MILLI;
// Avoid potential overflow if milli -> nano conversion is too large
while ms > MAX_MILLIS {
ms -= MAX_MILLIS;
self.delay_ns(MAX_MILLIS * NANOS_PER_MILLI);
}
self.delay_ns(ms * NANOS_PER_MILLI);
}
}
impl<T> DelayNs for &mut T
where
T: DelayNs + ?Sized,
{
#[inline]
fn delay_ns(&mut self, ns: u32) {
T::delay_ns(self, ns);
}
#[inline]
fn delay_us(&mut self, us: u32) {
T::delay_us(self, us);
}
#[inline]
fn delay_ms(&mut self, ms: u32) {
T::delay_ms(self, ms);
}
}