embassy/examples/stm32f2/src/bin/pll.rs

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2022-04-29 17:13:59 +02:00
#![no_std]
#![no_main]
#![feature(type_alias_impl_trait)]
use core::convert::TryFrom;
use defmt::*;
use embassy::executor::Spawner;
use embassy::time::{Duration, Timer};
use embassy_stm32::{
rcc::{
APBPrescaler, ClockSrc, HSEConfig, HSESrc, PLL48Div, PLLConfig, PLLMainDiv, PLLMul,
PLLPreDiv, PLLSrc,
},
time::Hertz,
Config, Peripherals,
};
use defmt_rtt as _; // global logger
use panic_probe as _;
// Example config for maximum performance on a NUCLEO-F207ZG board
fn config() -> Config {
let mut config = Config::default();
// By default, HSE on the board comes from a 8 MHz clock signal (not a crystal)
config.rcc.hse = Some(HSEConfig {
frequency: Hertz(8_000_000),
source: HSESrc::Bypass,
});
// PLL uses HSE as the clock source
config.rcc.pll_mux = PLLSrc::HSE;
config.rcc.pll = PLLConfig {
// 8 MHz clock source / 8 = 1 MHz PLL input
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pre_div: unwrap!(PLLPreDiv::try_from(8)),
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// 1 MHz PLL input * 240 = 240 MHz PLL VCO
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mul: unwrap!(PLLMul::try_from(240)),
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// 240 MHz PLL VCO / 2 = 120 MHz main PLL output
main_div: PLLMainDiv::Div2,
// 240 MHz PLL VCO / 5 = 48 MHz PLL48 output
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pll48_div: unwrap!(PLL48Div::try_from(5)),
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};
// System clock comes from PLL (= the 120 MHz main PLL output)
config.rcc.mux = ClockSrc::PLL;
// 120 MHz / 4 = 30 MHz APB1 frequency
config.rcc.apb1_pre = APBPrescaler::Div4;
// 120 MHz / 2 = 60 MHz APB2 frequency
config.rcc.apb2_pre = APBPrescaler::Div2;
config
}
#[embassy::main(config = "config()")]
async fn main(_spawner: Spawner, _p: Peripherals) {
loop {
Timer::after(Duration::from_millis(1000)).await;
info!("1s elapsed");
}
}