embassy_stm32/rcc/
hsi48.rs

1#![allow(unused)]
2
3use crate::pac::crs::vals::Syncsrc;
4use crate::pac::{CRS, RCC};
5use crate::rcc::{self, SealedRccPeripheral};
6use crate::time::Hertz;
7
8/// HSI48 speed
9pub const HSI48_FREQ: Hertz = Hertz(48_000_000);
10
11/// Configuration for the HSI48 clock
12#[derive(Clone, Copy, Debug)]
13pub struct Hsi48Config {
14    /// Enable CRS Sync from USB Start Of Frame (SOF) events.
15    /// Required if HSI48 is going to be used as USB clock.
16    ///
17    /// Other use cases of CRS are not supported yet.
18    pub sync_from_usb: bool,
19}
20
21impl Default for Hsi48Config {
22    fn default() -> Self {
23        Self { sync_from_usb: false }
24    }
25}
26
27pub(crate) fn init_hsi48(config: Hsi48Config) -> Hertz {
28    // Enable VREFINT reference for HSI48 oscillator
29    #[cfg(stm32l0)]
30    crate::pac::SYSCFG.cfgr3().modify(|w| {
31        w.set_enref_hsi48(true);
32        w.set_en_vrefint(true);
33    });
34
35    // Enable HSI48
36    #[cfg(not(any(stm32u5, stm32g0, stm32h5, stm32h7, stm32h7rs, stm32u5, stm32wba, stm32f0)))]
37    let r = RCC.crrcr();
38    #[cfg(any(stm32u5, stm32g0, stm32h5, stm32h7, stm32h7rs, stm32u5, stm32wba))]
39    let r = RCC.cr();
40    #[cfg(any(stm32f0))]
41    let r = RCC.cr2();
42
43    r.modify(|w| w.set_hsi48on(true));
44    while r.read().hsi48rdy() == false {}
45
46    if config.sync_from_usb {
47        rcc::enable_and_reset::<crate::peripherals::CRS>();
48
49        CRS.cfgr().modify(|w| {
50            w.set_syncsrc(Syncsrc::USB);
51        });
52
53        // These are the correct settings for standard USB operation. If other settings
54        // are needed there will need to be additional config options for the CRS.
55        crate::pac::CRS.cr().modify(|w| {
56            w.set_autotrimen(true);
57            w.set_cen(true);
58        });
59    }
60
61    HSI48_FREQ
62}
embassy_stm32/rcc/hsi48.rs

embassy_stm32/rcc/
hsi48.rs
