diff --git a/embassy-stm32/src/rcc/l4.rs b/embassy-stm32/src/rcc/l4.rs index f8c1a6e0..f7f3b904 100644 --- a/embassy-stm32/src/rcc/l4.rs +++ b/embassy-stm32/src/rcc/l4.rs @@ -1,6 +1,7 @@ use core::marker::PhantomData; use embassy_hal_common::into_ref; +use stm32_metapac::rcc::regs::Cfgr; use stm32_metapac::rcc::vals::{Lsedrv, Mcopre, Mcosel}; use crate::gpio::sealed::AFType; @@ -439,6 +440,26 @@ impl<'d, T: McoInstance> Mco<'d, T> { } pub(crate) unsafe fn init(config: Config) { + // Switch to MSI to prevent problems with PLL configuration. + if !RCC.cr().read().msion() { + // Turn on MSI and configure it to 4MHz. + RCC.cr().modify(|w| { + w.set_msirgsel(true); // MSI Range is provided by MSIRANGE[3:0]. + w.set_msirange(MSIRange::default().into()); + w.set_msipllen(false); + w.set_msion(true) + }); + + // Wait until MSI is running + while !RCC.cr().read().msirdy() {} + } + if RCC.cfgr().read().sws() != Sw::MSI { + // Set MSI as a clock source, reset prescalers. + RCC.cfgr().write_value(Cfgr::default()); + // Wait for clock switch status bits to change. + while RCC.cfgr().read().sws() != Sw::MSI {} + } + match config.rtc_mux { RtcClockSource::LSE32 => { // 1. Unlock the backup domain @@ -660,6 +681,8 @@ pub(crate) unsafe fn init(config: Config) { } }; + RCC.apb1enr1().modify(|w| w.set_pwren(true)); + set_freqs(Clocks { sys: Hertz(sys_clk), ahb1: Hertz(ahb_freq), diff --git a/examples/stm32l4/src/bin/rtc.rs b/examples/stm32l4/src/bin/rtc.rs new file mode 100644 index 00000000..0de70895 --- /dev/null +++ b/examples/stm32l4/src/bin/rtc.rs @@ -0,0 +1,50 @@ +#![no_std] +#![no_main] +#![feature(type_alias_impl_trait)] + +use chrono::{NaiveDate, NaiveDateTime}; +use defmt::*; +use embassy_executor::Spawner; +use embassy_stm32::rcc::{self, ClockSrc, PLLClkDiv, PLLMul, PLLSource, PLLSrcDiv}; +use embassy_stm32::rtc::{Rtc, RtcConfig}; +use embassy_stm32::time::Hertz; +use embassy_stm32::Config; +use embassy_time::{Duration, Timer}; +use {defmt_rtt as _, panic_probe as _}; + +#[embassy_executor::main] +async fn main(_spawner: Spawner) { + let p = { + let mut config = Config::default(); + config.rcc.mux = ClockSrc::PLL( + PLLSource::HSE(Hertz::mhz(8)), + PLLClkDiv::Div2, + PLLSrcDiv::Div1, + PLLMul::Mul20, + None, + ); + config.rcc.rtc_mux = rcc::RtcClockSource::LSE32; + embassy_stm32::init(config) + }; + info!("Hello World!"); + + let now = NaiveDate::from_ymd_opt(2020, 5, 15) + .unwrap() + .and_hms_opt(10, 30, 15) + .unwrap(); + + let mut rtc = Rtc::new( + p.RTC, + RtcConfig::default().clock_config(embassy_stm32::rtc::RtcClockSource::LSE), + ); + info!("Got RTC! {:?}", now.timestamp()); + + rtc.set_datetime(now.into()).expect("datetime not set"); + + // In reality the delay would be much longer + Timer::after(Duration::from_millis(20000)).await; + + let then: NaiveDateTime = rtc.now().unwrap().into(); + info!("Got RTC! {:?}", then.timestamp()); + +}