1//! Delays.
2
3/// Nanoseconds per microsecond
4const NANOS_PER_MICRO: u32 = 1_000;
5/// Nanoseconds per millisecond
6const NANOS_PER_MILLI: u32 = 1_000_000;
7
8/// Delay with up to nanosecond precision.
9pub trait DelayNs {
10 /// Pauses execution for at minimum `ns` nanoseconds. Pause can be longer
11 /// if the implementation requires it due to precision/timing issues.
12 fn delay_ns(&mut self, ns: u32);
13
14 /// Pauses execution for at minimum `us` microseconds. Pause can be longer
15 /// if the implementation requires it due to precision/timing issues.
16 fn delay_us(&mut self, mut us: u32) {
17 const MAX_MICROS: u32 = u32::MAX / NANOS_PER_MICRO;
18
19 // Avoid potential overflow if micro -> nano conversion is too large
20 while us > MAX_MICROS {
21 us -= MAX_MICROS;
22 self.delay_ns(MAX_MICROS * NANOS_PER_MICRO);
23 }
24
25 self.delay_ns(us * NANOS_PER_MICRO);
26 }
27
28 /// Pauses execution for at minimum `ms` milliseconds. Pause can be longer
29 /// if the implementation requires it due to precision/timing issues.
30 #[inline]
31 fn delay_ms(&mut self, mut ms: u32) {
32 const MAX_MILLIS: u32 = u32::MAX / NANOS_PER_MILLI;
33
34 // Avoid potential overflow if milli -> nano conversion is too large
35 while ms > MAX_MILLIS {
36 ms -= MAX_MILLIS;
37 self.delay_ns(MAX_MILLIS * NANOS_PER_MILLI);
38 }
39
40 self.delay_ns(ms * NANOS_PER_MILLI);
41 }
42}
43
44impl<T> DelayNs for &mut T
45where
46 T: DelayNs + ?Sized,
47{
48 #[inline]
49 fn delay_ns(&mut self, ns: u32) {
50 T::delay_ns(self, ns);
51 }
52
53 #[inline]
54 fn delay_us(&mut self, us: u32) {
55 T::delay_us(self, us);
56 }
57
58 #[inline]
59 fn delay_ms(&mut self, ms: u32) {
60 T::delay_ms(self, ms);
61 }
62}
63