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|
use crate::{
analog::AcCapture,
fixpt::Fixpt,
mutex::{MainCtx, MutexCell},
timer::{timer_get, RelTimestamp, Timestamp, TIMER_TICK_US},
};
/// 2 edge (rising falling) in AC capture.
/// 4 speedometer edges per motor revolution
const SPEEDO_FACT: u32 = 4 * 2;
const OK_THRES: u8 = 4;
pub struct MotorSpeed(Fixpt);
impl MotorSpeed {
const FACT_16HZ: u16 = 16;
pub fn zero() -> Self {
Self(Fixpt::from_int(0))
}
fn from_period_dur(dur: RelTimestamp) -> Self {
let dur: i8 = dur.into();
let dur: u8 = dur as _;
// fact 2 to avoid rounding error.
let num = (1_000_000 / (TIMER_TICK_US as u32 * (SPEEDO_FACT / 2))) as u16;
let denom = dur as u16 * Self::FACT_16HZ * 2;
Self(Fixpt::from_fraction(num as i16, denom as i16))
}
pub fn as_16hz(&self) -> Fixpt {
self.0
}
}
pub struct Speedo {
ok_count: MutexCell<u8>,
prev_stamp: MutexCell<Timestamp>,
dur: [MutexCell<u8>; 4],
}
impl Speedo {
pub const fn new() -> Self {
Self {
ok_count: MutexCell::new(0),
prev_stamp: MutexCell::new(Timestamp::new()),
dur: [
MutexCell::new(0),
MutexCell::new(0),
MutexCell::new(0),
MutexCell::new(0),
],
}
}
pub fn get_speed(&self, m: &MainCtx<'_>) -> Option<MotorSpeed> {
if self.ok_count.get(m) < OK_THRES {
None
} else {
Some(MotorSpeed::from_period_dur(self.get_dur(m)))
}
}
pub fn get_dur(&self, m: &MainCtx<'_>) -> RelTimestamp {
let a = self.dur[0].get(m) as u16;
let b = self.dur[1].get(m) as u16;
let c = self.dur[2].get(m) as u16;
let d = self.dur[3].get(m) as u16;
let dur: u8 = ((a + b + c + d) / 4) as _;
let dur: i8 = dur as _;
dur.into()
}
fn new_duration(&self, m: &MainCtx<'_>, dur: RelTimestamp) {
let dur: i8 = dur.into();
self.dur[0].set(m, self.dur[1].get(m));
self.dur[1].set(m, self.dur[2].get(m));
self.dur[2].set(m, self.dur[3].get(m));
self.dur[3].set(m, dur as _);
self.ok_count.set(m, self.ok_count.get(m).saturating_add(1));
}
pub fn update(&self, m: &MainCtx<'_>, ac: &AcCapture) {
let now = timer_get(&m.to_any());
let prev_stamp = self.prev_stamp.get(m);
if now < prev_stamp {
// prev_stamp wrapped. Drop it.
self.ok_count.set(m, 0);
}
if ac.is_new() {
let ac_stamp = ac.stamp();
if ac_stamp >= prev_stamp {
let dur = ac_stamp - prev_stamp;
self.new_duration(m, dur);
} else {
// prev_stamp wrapped.
self.ok_count.set(m, 0);
}
self.prev_stamp.set(m, ac_stamp);
}
}
}
// vim: ts=4 sw=4 expandtab
|
