embassy/embassy-stm32/src/rtc/low_power.rs
Gerzain Mata d9cd93ca22 Added RTC low-power support for STM32WBA65
Also added low-power feature for STM32WBA65RI build
2025-07-18 14:25:15 -07:00

258 lines
8.6 KiB
Rust

use super::{bcd2_to_byte, DateTimeError, Rtc, RtcError};
use crate::peripherals::RTC;
use crate::rtc::SealedInstance;
/// Represents an instant in time that can be substracted to compute a duration
pub(super) struct RtcInstant {
/// 0..59
second: u8,
/// 0..256
subsecond: u16,
}
impl RtcInstant {
#[cfg(not(rtc_v2f2))]
const fn from(second: u8, subsecond: u16) -> Result<Self, DateTimeError> {
if second > 59 {
Err(DateTimeError::InvalidSecond)
} else {
Ok(Self { second, subsecond })
}
}
}
#[cfg(feature = "defmt")]
impl defmt::Format for RtcInstant {
fn format(&self, fmt: defmt::Formatter) {
defmt::write!(
fmt,
"{}:{}",
self.second,
RTC::regs().prer().read().prediv_s() - self.subsecond,
)
}
}
#[cfg(feature = "time")]
impl core::ops::Sub for RtcInstant {
type Output = embassy_time::Duration;
fn sub(self, rhs: Self) -> Self::Output {
use embassy_time::{Duration, TICK_HZ};
let second = if self.second < rhs.second {
self.second + 60
} else {
self.second
};
let psc = RTC::regs().prer().read().prediv_s() as u32;
let self_ticks = second as u32 * (psc + 1) + (psc - self.subsecond as u32);
let other_ticks = rhs.second as u32 * (psc + 1) + (psc - rhs.subsecond as u32);
let rtc_ticks = self_ticks - other_ticks;
Duration::from_ticks(((rtc_ticks * TICK_HZ as u32) / (psc + 1)) as u64)
}
}
#[repr(u8)]
#[derive(Clone, Copy, Debug)]
pub(crate) enum WakeupPrescaler {
Div2 = 2,
Div4 = 4,
Div8 = 8,
Div16 = 16,
}
#[cfg(any(
stm32f4, stm32l0, stm32g4, stm32l4, stm32l5, stm32wb, stm32h5, stm32g0, stm32u5, stm32u0, stm32wba
))]
impl From<WakeupPrescaler> for crate::pac::rtc::vals::Wucksel {
fn from(val: WakeupPrescaler) -> Self {
use crate::pac::rtc::vals::Wucksel;
match val {
WakeupPrescaler::Div2 => Wucksel::DIV2,
WakeupPrescaler::Div4 => Wucksel::DIV4,
WakeupPrescaler::Div8 => Wucksel::DIV8,
WakeupPrescaler::Div16 => Wucksel::DIV16,
}
}
}
#[cfg(any(
stm32f4, stm32l0, stm32g4, stm32l4, stm32l5, stm32wb, stm32h5, stm32g0, stm32u5, stm32u0, stm32wba
))]
impl From<crate::pac::rtc::vals::Wucksel> for WakeupPrescaler {
fn from(val: crate::pac::rtc::vals::Wucksel) -> Self {
use crate::pac::rtc::vals::Wucksel;
match val {
Wucksel::DIV2 => WakeupPrescaler::Div2,
Wucksel::DIV4 => WakeupPrescaler::Div4,
Wucksel::DIV8 => WakeupPrescaler::Div8,
Wucksel::DIV16 => WakeupPrescaler::Div16,
_ => unreachable!(),
}
}
}
impl WakeupPrescaler {
pub fn compute_min(val: u32) -> Self {
*[
WakeupPrescaler::Div2,
WakeupPrescaler::Div4,
WakeupPrescaler::Div8,
WakeupPrescaler::Div16,
]
.iter()
.find(|psc| **psc as u32 > val)
.unwrap_or(&WakeupPrescaler::Div16)
}
}
impl Rtc {
/// Return the current instant.
fn instant(&self) -> Result<RtcInstant, RtcError> {
self.time_provider().read(|_, tr, ss| {
let second = bcd2_to_byte((tr.st(), tr.su()));
RtcInstant::from(second, ss).map_err(RtcError::InvalidDateTime)
})
}
/// start the wakeup alarm and with a duration that is as close to but less than
/// the requested duration, and record the instant the wakeup alarm was started
pub(crate) fn start_wakeup_alarm(
&self,
requested_duration: embassy_time::Duration,
cs: critical_section::CriticalSection,
) {
use embassy_time::{Duration, TICK_HZ};
#[cfg(any(rtc_v3, rtc_v3u5, rtc_v3l5))]
use crate::pac::rtc::vals::Calrf;
// Panic if the rcc mod knows we're not using low-power rtc
#[cfg(any(rcc_wb, rcc_f4, rcc_f410))]
unsafe { crate::rcc::get_freqs() }.rtc.to_hertz().unwrap();
let requested_duration = requested_duration.as_ticks().clamp(0, u32::MAX as u64);
let rtc_hz = Self::frequency().0 as u64;
let rtc_ticks = requested_duration * rtc_hz / TICK_HZ;
let prescaler = WakeupPrescaler::compute_min((rtc_ticks / u16::MAX as u64) as u32);
// adjust the rtc ticks to the prescaler and subtract one rtc tick
let rtc_ticks = rtc_ticks / prescaler as u64;
let rtc_ticks = rtc_ticks.clamp(0, (u16::MAX - 1) as u64).saturating_sub(1) as u16;
self.write(false, |regs| {
regs.cr().modify(|w| w.set_wute(false));
#[cfg(any(
rtc_v2f0, rtc_v2f2, rtc_v2f3, rtc_v2f4, rtc_v2f7, rtc_v2h7, rtc_v2l0, rtc_v2l1, rtc_v2l4, rtc_v2wb
))]
{
regs.isr().modify(|w| w.set_wutf(false));
while !regs.isr().read().wutwf() {}
}
#[cfg(any(rtc_v3, rtc_v3u5, rtc_v3l5))]
{
regs.scr().write(|w| w.set_cwutf(Calrf::CLEAR));
while !regs.icsr().read().wutwf() {}
}
regs.cr().modify(|w| w.set_wucksel(prescaler.into()));
regs.wutr().write(|w| w.set_wut(rtc_ticks));
regs.cr().modify(|w| w.set_wute(true));
regs.cr().modify(|w| w.set_wutie(true));
});
let instant = self.instant().unwrap();
trace!(
"rtc: start wakeup alarm for {} ms (psc: {}, ticks: {}) at {}",
Duration::from_ticks(rtc_ticks as u64 * TICK_HZ * prescaler as u64 / rtc_hz).as_millis(),
prescaler as u32,
rtc_ticks,
instant,
);
assert!(self.stop_time.borrow(cs).replace(Some(instant)).is_none())
}
/// stop the wakeup alarm and return the time elapsed since `start_wakeup_alarm`
/// was called, otherwise none
pub(crate) fn stop_wakeup_alarm(&self, cs: critical_section::CriticalSection) -> Option<embassy_time::Duration> {
use crate::interrupt::typelevel::Interrupt;
#[cfg(any(rtc_v3, rtc_v3u5, rtc_v3l5))]
use crate::pac::rtc::vals::Calrf;
let instant = self.instant().unwrap();
if RTC::regs().cr().read().wute() {
trace!("rtc: stop wakeup alarm at {}", instant);
self.write(false, |regs| {
regs.cr().modify(|w| w.set_wutie(false));
regs.cr().modify(|w| w.set_wute(false));
#[cfg(any(
rtc_v2f0, rtc_v2f2, rtc_v2f3, rtc_v2f4, rtc_v2f7, rtc_v2h7, rtc_v2l0, rtc_v2l1, rtc_v2l4, rtc_v2wb
))]
regs.isr().modify(|w| w.set_wutf(false));
#[cfg(any(rtc_v3, rtc_v3u5, rtc_v3l5))]
regs.scr().write(|w| w.set_cwutf(Calrf::CLEAR));
// Check RM for EXTI and/or NVIC section, "Event event input mapping" or "EXTI interrupt/event mapping" or something similar,
// there is a table for every "Event input" / "EXTI Line".
// If you find the EXTI line related to "RTC wakeup" marks as "Configurable" (not "Direct"),
// then write 1 to related field of Pending Register, to clean it's pending state.
#[cfg(any(exti_v1, stm32h7, stm32wb))]
crate::pac::EXTI
.pr(0)
.modify(|w| w.set_line(RTC::EXTI_WAKEUP_LINE, true));
<RTC as crate::rtc::SealedInstance>::WakeupInterrupt::unpend();
});
}
self.stop_time.borrow(cs).take().map(|stop_time| instant - stop_time)
}
pub(crate) fn enable_wakeup_line(&self) {
use crate::interrupt::typelevel::Interrupt;
<RTC as crate::rtc::SealedInstance>::WakeupInterrupt::unpend();
unsafe { <RTC as crate::rtc::SealedInstance>::WakeupInterrupt::enable() };
#[cfg(not(any(stm32u5, stm32u0, stm32wba)))]
{
use crate::pac::EXTI;
EXTI.rtsr(0).modify(|w| w.set_line(RTC::EXTI_WAKEUP_LINE, true));
#[cfg(not(stm32wb))]
{
EXTI.imr(0).modify(|w| w.set_line(RTC::EXTI_WAKEUP_LINE, true));
}
#[cfg(stm32wb)]
{
EXTI.cpu(0).imr(0).modify(|w| w.set_line(RTC::EXTI_WAKEUP_LINE, true));
}
}
#[cfg(stm32u5)]
{
use crate::pac::RCC;
RCC.srdamr().modify(|w| w.set_rtcapbamen(true));
RCC.apb3smenr().modify(|w| w.set_rtcapbsmen(true));
}
#[cfg(stm32wba)]
{
use crate::pac::RCC;
// RCC.srdamr().modify(|w| w.set_rtcapbamen(true));
RCC.apb7smenr().modify(|w| w.set_rtcapbsmen(true));
}
}
}