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use crate::pac::{PWR, RCC};
use crate::rcc::{set_freqs, Clocks};
use crate::time::Hertz;
use crate::time::U32Ext;
/// HSI speed
pub const HSI_FREQ: u32 = 16_000_000;
/// LSI speed
pub const LSI_FREQ: u32 = 32_000;
/// System clock mux source
#[derive(Clone, Copy)]
pub enum ClockSrc {
HSE(Hertz),
HSI16,
}
/// AHB prescaler
#[derive(Clone, Copy, PartialEq)]
pub enum AHBPrescaler {
NotDivided,
Div2,
Div4,
Div8,
Div16,
Div64,
Div128,
Div256,
Div512,
}
/// APB prescaler
#[derive(Clone, Copy)]
pub enum APBPrescaler {
NotDivided,
Div2,
Div4,
Div8,
Div16,
}
impl Into<u8> for APBPrescaler {
fn into(self) -> u8 {
match self {
APBPrescaler::NotDivided => 1,
APBPrescaler::Div2 => 0x04,
APBPrescaler::Div4 => 0x05,
APBPrescaler::Div8 => 0x06,
APBPrescaler::Div16 => 0x07,
}
}
}
impl Into<u8> for AHBPrescaler {
fn into(self) -> u8 {
match self {
AHBPrescaler::NotDivided => 1,
AHBPrescaler::Div2 => 0x08,
AHBPrescaler::Div4 => 0x09,
AHBPrescaler::Div8 => 0x0a,
AHBPrescaler::Div16 => 0x0b,
AHBPrescaler::Div64 => 0x0c,
AHBPrescaler::Div128 => 0x0d,
AHBPrescaler::Div256 => 0x0e,
AHBPrescaler::Div512 => 0x0f,
}
}
}
/// Clocks configutation
pub struct Config {
pub mux: ClockSrc,
pub ahb_pre: AHBPrescaler,
pub apb1_pre: APBPrescaler,
pub apb2_pre: APBPrescaler,
pub low_power_run: bool,
}
impl Default for Config {
#[inline]
fn default() -> Config {
Config {
mux: ClockSrc::HSI16,
ahb_pre: AHBPrescaler::NotDivided,
apb1_pre: APBPrescaler::NotDivided,
apb2_pre: APBPrescaler::NotDivided,
low_power_run: false,
}
}
}
pub(crate) unsafe fn init(config: Config) {
let (sys_clk, sw) = match config.mux {
ClockSrc::HSI16 => {
// Enable HSI16
RCC.cr().write(|w| w.set_hsion(true));
while !RCC.cr().read().hsirdy() {}
(HSI_FREQ, 0x01)
}
ClockSrc::HSE(freq) => {
// Enable HSE
RCC.cr().write(|w| w.set_hseon(true));
while !RCC.cr().read().hserdy() {}
(freq.0, 0x02)
}
};
RCC.cfgr().modify(|w| {
w.set_sw(sw.into());
w.set_hpre(config.ahb_pre.into());
w.set_ppre1(config.apb1_pre.into());
w.set_ppre2(config.apb2_pre.into());
});
let ahb_freq: u32 = match config.ahb_pre {
AHBPrescaler::NotDivided => sys_clk,
pre => {
let pre: u8 = pre.into();
let pre = 1 << (pre as u32 - 7);
sys_clk / pre
}
};
let (apb1_freq, apb1_tim_freq) = match config.apb1_pre {
APBPrescaler::NotDivided => (ahb_freq, ahb_freq),
pre => {
let pre: u8 = pre.into();
let pre: u8 = 1 << (pre - 3);
let freq = ahb_freq / pre as u32;
(freq, freq * 2)
}
};
let (apb2_freq, apb2_tim_freq) = match config.apb2_pre {
APBPrescaler::NotDivided => (ahb_freq, ahb_freq),
pre => {
let pre: u8 = pre.into();
let pre: u8 = 1 << (pre - 3);
let freq = ahb_freq / pre as u32;
(freq, freq * 2)
}
};
if config.low_power_run {
assert!(sys_clk.hz() <= 2_000_000.hz());
PWR.cr1().modify(|w| w.set_lpr(true));
}
set_freqs(Clocks {
sys: sys_clk.hz(),
ahb1: ahb_freq.hz(),
ahb2: ahb_freq.hz(),
apb1: apb1_freq.hz(),
apb1_tim: apb1_tim_freq.hz(),
apb2: apb2_freq.hz(),
apb2_tim: apb2_tim_freq.hz(),
});
}
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