[−][src]Crate embedded_time
embedded-time
provides a comprehensive library for implementing Clock
abstractions over
hardware to generate Instant
s and using Duration
s (Seconds
, Milliseconds
, etc)
in embedded systems. The approach is similar to the C++ chrono
library. A Duration
consists of an integer (whose type is chosen by the user to be either i32
or i64
) as
well as a const
ratio where the integer value multiplied by the ratio is the Duration
in
seconds. Put another way, the ratio is the precision of the LSbit of the integer. This structure
avoids unnecessary arithmetic. For example, if the Duration
type is Milliseconds
, a call
to the Duration::count()
method simply returns the stored integer value directly which is
the number of milliseconds being represented. Conversion arithmetic is only performed when
explicitly converting between time units.
Definitions
Clock: Any entity that periodically counts (ie a hardware timer peripheral). Generally, this needs to be monotonic. A wrapping clock is considered monotonic in this context as long as it fulfills the other requirements.
Wrapping Clock: A clock that when at its maximum value, the next count is the minimum value.
Instant: A specific instant in time ("time-point") returned by calling Clock::now()
.
Duration: The difference of two instances. The duration of time elapsed from one instant until another. A span of time.
Notes
Some parts of this crate were derived from various sources:
RTFM
time
(Specifically thetime::NumbericalDuration
implementations for primitive integers)
Example Usage
struct SomeClock; impl embedded_time::Clock for SomeClock { type Rep = i64; const PERIOD: Period = Period::new_raw(1, 16_000_000); fn now() -> Instant<Self> { // ... } } let instant1 = SomeClock::now(); // ... let instant2 = SomeClock::now(); assert!(instant1 < instant2); // instant1 is *before* instant2 // duration is the difference between the instances let duration: Option<Microseconds<i64>> = instant2.duration_since(&instant1); assert!(duration.is_some()); assert_eq!(instant1 + duration.unwrap(), instant2);
Re-exports
pub use duration::time_units; |
pub use duration::Duration; |
Modules
duration | Duration types/units creation and conversion. |
instant | An instant of time |
prelude | A collection of imports that are widely useful. |
Traits
Clock | |
TimeRep | Create |
Type Definitions
Period |