109 lines
3.0 KiB
Rust
109 lines
3.0 KiB
Rust
//! Quadrature decoder using a timer.
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use core::marker::PhantomData;
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use embassy_hal_internal::{into_ref, PeripheralRef};
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use stm32_metapac::timer::vals;
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use super::low_level::Timer;
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use super::{Channel1Pin, Channel2Pin, GeneralInstance4Channel};
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use crate::gpio::{AFType, AnyPin};
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use crate::Peripheral;
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/// Counting direction
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pub enum Direction {
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/// Counting up.
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Upcounting,
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/// Counting down.
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Downcounting,
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}
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/// Channel 1 marker type.
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pub enum Ch1 {}
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/// Channel 2 marker type.
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pub enum Ch2 {}
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/// Wrapper for using a pin with QEI.
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pub struct QeiPin<'d, T, Channel> {
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_pin: PeripheralRef<'d, AnyPin>,
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phantom: PhantomData<(T, Channel)>,
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}
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macro_rules! channel_impl {
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($new_chx:ident, $channel:ident, $pin_trait:ident) => {
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impl<'d, T: GeneralInstance4Channel> QeiPin<'d, T, $channel> {
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#[doc = concat!("Create a new ", stringify!($channel), " QEI pin instance.")]
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pub fn $new_chx(pin: impl Peripheral<P = impl $pin_trait<T>> + 'd) -> Self {
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into_ref!(pin);
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critical_section::with(|_| {
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pin.set_low();
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pin.set_as_af(pin.af_num(), AFType::Input);
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#[cfg(gpio_v2)]
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pin.set_speed(crate::gpio::Speed::VeryHigh);
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});
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QeiPin {
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_pin: pin.map_into(),
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phantom: PhantomData,
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}
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}
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}
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};
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}
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channel_impl!(new_ch1, Ch1, Channel1Pin);
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channel_impl!(new_ch2, Ch2, Channel2Pin);
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/// Quadrature decoder driver.
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pub struct Qei<'d, T: GeneralInstance4Channel> {
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inner: Timer<'d, T>,
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}
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impl<'d, T: GeneralInstance4Channel> Qei<'d, T> {
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/// Create a new quadrature decoder driver.
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pub fn new(tim: impl Peripheral<P = T> + 'd, _ch1: QeiPin<'d, T, Ch1>, _ch2: QeiPin<'d, T, Ch2>) -> Self {
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Self::new_inner(tim)
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}
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fn new_inner(tim: impl Peripheral<P = T> + 'd) -> Self {
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let inner = Timer::new(tim);
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let r = inner.regs_gp16();
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// Configure TxC1 and TxC2 as captures
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r.ccmr_input(0).modify(|w| {
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w.set_ccs(0, vals::CcmrInputCcs::TI4);
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w.set_ccs(1, vals::CcmrInputCcs::TI4);
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});
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// enable and configure to capture on rising edge
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r.ccer().modify(|w| {
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w.set_cce(0, true);
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w.set_cce(1, true);
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w.set_ccp(0, false);
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w.set_ccp(1, false);
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});
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r.smcr().modify(|w| {
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w.set_sms(vals::Sms::ENCODER_MODE_3);
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});
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r.arr().modify(|w| w.set_arr(u16::MAX));
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r.cr1().modify(|w| w.set_cen(true));
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Self { inner }
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}
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/// Get direction.
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pub fn read_direction(&self) -> Direction {
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match self.inner.regs_gp16().cr1().read().dir() {
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vals::Dir::DOWN => Direction::Downcounting,
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vals::Dir::UP => Direction::Upcounting,
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}
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}
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/// Get count.
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pub fn count(&self) -> u16 {
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self.inner.regs_gp16().cnt().read().cnt()
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}
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}
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