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embassy/embassy-stm32/src/rcc/h7.rs

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use core::marker::PhantomData;
use embassy_hal_common::into_ref;
pub use pll::PllConfig;
use stm32_metapac::rcc::vals::{Mco1, Mco2};
use crate::gpio::sealed::AFType;
use crate::gpio::Speed;
use crate::pac::rcc::vals::{Adcsel, Ckpersel, Dppre, Hpre, Hsidiv, Pllsrc, Sw, Timpre};
use crate::pac::{PWR, RCC, SYSCFG};
use crate::rcc::{set_freqs, Clocks};
use crate::time::Hertz;
use crate::{peripherals, Peripheral};
/// HSI speed
pub const HSI_FREQ: Hertz = Hertz(64_000_000);
/// CSI speed
pub const CSI_FREQ: Hertz = Hertz(4_000_000);
/// HSI48 speed
pub const HSI48_FREQ: Hertz = Hertz(48_000_000);
/// LSI speed
pub const LSI_FREQ: Hertz = Hertz(32_000);
/// Voltage Scale
///
/// Represents the voltage range feeding the CPU core. The maximum core
/// clock frequency depends on this value.
#[derive(Copy, Clone, PartialEq)]
pub enum VoltageScale {
/// VOS 0 range VCORE 1.26V - 1.40V
Scale0,
/// VOS 1 range VCORE 1.15V - 1.26V
Scale1,
/// VOS 2 range VCORE 1.05V - 1.15V
Scale2,
/// VOS 3 range VCORE 0.95V - 1.05V
Scale3,
}
#[derive(Clone, Copy)]
pub enum AdcClockSource {
Pll2PCk,
Pll3RCk,
PerCk,
}
impl AdcClockSource {
pub fn adcsel(&self) -> Adcsel {
match self {
AdcClockSource::Pll2PCk => Adcsel::PLL2_P,
AdcClockSource::Pll3RCk => Adcsel::PLL3_R,
AdcClockSource::PerCk => Adcsel::PER,
}
}
}
impl Default for AdcClockSource {
fn default() -> Self {
Self::Pll2PCk
}
}
/// Core clock frequencies
#[derive(Clone, Copy)]
pub struct CoreClocks {
pub hclk: Hertz,
pub pclk1: Hertz,
pub pclk2: Hertz,
pub pclk3: Hertz,
pub pclk4: Hertz,
pub ppre1: u8,
pub ppre2: u8,
pub ppre3: u8,
pub ppre4: u8,
pub csi_ck: Option<Hertz>,
pub hsi_ck: Option<Hertz>,
pub hsi48_ck: Option<Hertz>,
pub lsi_ck: Option<Hertz>,
pub per_ck: Option<Hertz>,
pub hse_ck: Option<Hertz>,
pub pll1_p_ck: Option<Hertz>,
pub pll1_q_ck: Option<Hertz>,
pub pll1_r_ck: Option<Hertz>,
pub pll2_p_ck: Option<Hertz>,
pub pll2_q_ck: Option<Hertz>,
pub pll2_r_ck: Option<Hertz>,
pub pll3_p_ck: Option<Hertz>,
pub pll3_q_ck: Option<Hertz>,
pub pll3_r_ck: Option<Hertz>,
pub timx_ker_ck: Option<Hertz>,
pub timy_ker_ck: Option<Hertz>,
pub adc_ker_ck: Option<Hertz>,
pub sys_ck: Hertz,
pub c_ck: Hertz,
}
/// Configuration of the core clocks
#[non_exhaustive]
#[derive(Default)]
pub struct Config {
pub hse: Option<Hertz>,
pub bypass_hse: bool,
pub sys_ck: Option<Hertz>,
pub per_ck: Option<Hertz>,
pub hclk: Option<Hertz>,
pub pclk1: Option<Hertz>,
pub pclk2: Option<Hertz>,
pub pclk3: Option<Hertz>,
pub pclk4: Option<Hertz>,
pub pll1: PllConfig,
pub pll2: PllConfig,
pub pll3: PllConfig,
pub adc_clock_source: AdcClockSource,
}
/// Setup traceclk
/// Returns a pll1_r_ck
fn traceclk_setup(config: &mut Config, sys_use_pll1_p: bool) {
let pll1_r_ck = match (sys_use_pll1_p, config.pll1.r_ck) {
// pll1_p_ck selected as system clock but pll1_r_ck not
// set. The traceclk mux is synchronous with the system
// clock mux, but has pll1_r_ck as an input. In order to
// keep traceclk running, we force a pll1_r_ck.
(true, None) => Some(Hertz(unwrap!(config.pll1.p_ck).0 / 2)),
// Either pll1 not selected as system clock, free choice
// of pll1_r_ck. Or pll1 is selected, assume user has set
// a suitable pll1_r_ck frequency.
_ => config.pll1.r_ck,
};
config.pll1.r_ck = pll1_r_ck;
}
/// Divider calculator for pclk 1 - 4
///
/// Returns real pclk, bits, ppre and the timer kernel clock
fn ppre_calculate(
requested_pclk: u32,
hclk: u32,
max_pclk: u32,
tim_pre: Option<Timpre>,
) -> (u32, u8, u8, Option<u32>) {
let (bits, ppre) = match (hclk + requested_pclk - 1) / requested_pclk {
0 => panic!(),
1 => (0b000, 1),
2 => (0b100, 2),
3..=5 => (0b101, 4),
6..=11 => (0b110, 8),
_ => (0b111, 16),
};
let real_pclk = hclk / u32::from(ppre);
assert!(real_pclk <= max_pclk);
let tim_ker_clk = if let Some(tim_pre) = tim_pre {
let clk = match (bits, tim_pre) {
(0b101, Timpre::DEFAULTX2) => hclk / 2,
(0b110, Timpre::DEFAULTX4) => hclk / 2,
(0b110, Timpre::DEFAULTX2) => hclk / 4,
(0b111, Timpre::DEFAULTX4) => hclk / 4,
(0b111, Timpre::DEFAULTX2) => hclk / 8,
_ => hclk,
};
Some(clk)
} else {
None
};
(real_pclk, bits, ppre, tim_ker_clk)
}
/// Setup sys_ck
/// Returns sys_ck frequency, and a pll1_p_ck
fn sys_ck_setup(config: &mut Config, srcclk: Hertz) -> (Hertz, bool) {
// Compare available with wanted clocks
let sys_ck = config.sys_ck.unwrap_or(srcclk);
if sys_ck != srcclk {
// The requested system clock is not the immediately available
// HSE/HSI clock. Perhaps there are other ways of obtaining
// the requested system clock (such as `HSIDIV`) but we will
// ignore those for now.
//
// Therefore we must use pll1_p_ck
let pll1_p_ck = match config.pll1.p_ck {
Some(p_ck) => {
assert!(
p_ck == sys_ck,
"Error: Cannot set pll1_p_ck independently as it must be used to generate sys_ck"
);
Some(p_ck)
}
None => Some(sys_ck),
};
config.pll1.p_ck = pll1_p_ck;
(sys_ck, true)
} else {
// sys_ck is derived directly from a source clock
// (HSE/HSI). pll1_p_ck can be as requested
(sys_ck, false)
}
}
fn flash_setup(rcc_aclk: u32, vos: VoltageScale) {
use crate::pac::FLASH;
// ACLK in MHz, round down and subtract 1 from integers. eg.
// 61_999_999 -> 61MHz
// 62_000_000 -> 61MHz
// 62_000_001 -> 62MHz
let rcc_aclk_mhz = (rcc_aclk - 1) / 1_000_000;
// See RM0433 Rev 7 Table 17. FLASH recommended number of wait
// states and programming delay
let (wait_states, progr_delay) = match vos {
// VOS 0 range VCORE 1.26V - 1.40V
VoltageScale::Scale0 => match rcc_aclk_mhz {
0..=69 => (0, 0),
70..=139 => (1, 1),
140..=184 => (2, 1),
185..=209 => (2, 2),
210..=224 => (3, 2),
225..=239 => (4, 2),
_ => (7, 3),
},
// VOS 1 range VCORE 1.15V - 1.26V
VoltageScale::Scale1 => match rcc_aclk_mhz {
0..=69 => (0, 0),
70..=139 => (1, 1),
140..=184 => (2, 1),
185..=209 => (2, 2),
210..=224 => (3, 2),
_ => (7, 3),
},
// VOS 2 range VCORE 1.05V - 1.15V
VoltageScale::Scale2 => match rcc_aclk_mhz {
0..=54 => (0, 0),
55..=109 => (1, 1),
110..=164 => (2, 1),
165..=224 => (3, 2),
_ => (7, 3),
},
// VOS 3 range VCORE 0.95V - 1.05V
VoltageScale::Scale3 => match rcc_aclk_mhz {
0..=44 => (0, 0),
45..=89 => (1, 1),
90..=134 => (2, 1),
135..=179 => (3, 2),
180..=224 => (4, 2),
_ => (7, 3),
},
};
// NOTE(unsafe) Atomic write
unsafe {
FLASH.acr().write(|w| {
w.set_wrhighfreq(progr_delay);
w.set_latency(wait_states)
});
while FLASH.acr().read().latency() != wait_states {}
}
}
pub enum McoClock {
Disabled,
Bypassed,
Divided(u8),
}
impl McoClock {
fn into_raw(&self) -> u8 {
match self {
McoClock::Disabled => 0,
McoClock::Bypassed => 1,
McoClock::Divided(divisor) => {
if *divisor > 15 {
panic!("Mco divisor must be less than 15. Refer to the reference manual for more information.")
}
*divisor
}
}
}
}
#[derive(Copy, Clone)]
pub enum Mco1Source {
Hsi,
Lse,
Hse,
Pll1Q,
Hsi48,
}
impl Default for Mco1Source {
fn default() -> Self {
Self::Hsi
}
}
pub trait McoSource {
type Raw;
fn into_raw(&self) -> Self::Raw;
}
impl McoSource for Mco1Source {
type Raw = Mco1;
fn into_raw(&self) -> Self::Raw {
match self {
Mco1Source::Hsi => Mco1::HSI,
Mco1Source::Lse => Mco1::LSE,
Mco1Source::Hse => Mco1::HSE,
Mco1Source::Pll1Q => Mco1::PLL1_Q,
Mco1Source::Hsi48 => Mco1::HSI48,
}
}
}
#[derive(Copy, Clone)]
pub enum Mco2Source {
SysClk,
Pll2Q,
Hse,
Pll1Q,
Csi,
Lsi,
}
impl Default for Mco2Source {
fn default() -> Self {
Self::SysClk
}
}
impl McoSource for Mco2Source {
type Raw = Mco2;
fn into_raw(&self) -> Self::Raw {
match self {
Mco2Source::SysClk => Mco2::SYSCLK,
Mco2Source::Pll2Q => Mco2::PLL2_P,
Mco2Source::Hse => Mco2::HSE,
Mco2Source::Pll1Q => Mco2::PLL1_P,
Mco2Source::Csi => Mco2::CSI,
Mco2Source::Lsi => Mco2::LSI,
}
}
}
pub(crate) mod sealed {
pub trait McoInstance {
type Source;
unsafe fn apply_clock_settings(source: Self::Source, prescaler: u8);
}
}
pub trait McoInstance: sealed::McoInstance + 'static {}
pin_trait!(McoPin, McoInstance);
macro_rules! impl_peri {
($peri:ident, $source:ident, $set_source:ident, $set_prescaler:ident) => {
impl sealed::McoInstance for peripherals::$peri {
type Source = $source;
unsafe fn apply_clock_settings(source: Self::Source, prescaler: u8) {
RCC.cfgr().modify(|w| {
w.$set_source(source);
w.$set_prescaler(prescaler);
});
}
}
impl McoInstance for peripherals::$peri {}
};
}
impl_peri!(MCO1, Mco1, set_mco1, set_mco1pre);
impl_peri!(MCO2, Mco2, set_mco2, set_mco2pre);
pub struct Mco<'d, T: McoInstance> {
phantom: PhantomData<&'d mut T>,
}
impl<'d, T: McoInstance> Mco<'d, T> {
pub fn new(
_peri: impl Peripheral<P = T> + 'd,
pin: impl Peripheral<P = impl McoPin<T>> + 'd,
source: impl McoSource<Raw = T::Source>,
prescaler: McoClock,
) -> Self {
into_ref!(pin);
critical_section::with(|_| unsafe {
T::apply_clock_settings(source.into_raw(), prescaler.into_raw());
pin.set_as_af(pin.af_num(), AFType::OutputPushPull);
pin.set_speed(Speed::VeryHigh);
});
Self { phantom: PhantomData }
}
}
pub(crate) unsafe fn init(mut config: Config) {
// TODO make configurable?
let enable_overdrive = false;
// NB. The lower bytes of CR3 can only be written once after
// POR, and must be written with a valid combination. Refer to
// RM0433 Rev 7 6.8.4. This is partially enforced by dropping
// `self` at the end of this method, but of course we cannot
// know what happened between the previous POR and here.
#[cfg(pwr_h7)]
PWR.cr3().modify(|w| {
w.set_scuen(true);
w.set_ldoen(true);
w.set_bypass(false);
});
#[cfg(pwr_h7smps)]
PWR.cr3().modify(|w| {
// hardcode "Direct SPMS" for now, this is what works on nucleos with the
// default solderbridge configuration.
w.set_sden(true);
w.set_ldoen(false);
});
// Validate the supply configuration. If you are stuck here, it is
// because the voltages on your board do not match those specified
// in the D3CR.VOS and CR3.SDLEVEL fields. By default after reset
// VOS = Scale 3, so check that the voltage on the VCAP pins =
// 1.0V.
while !PWR.csr1().read().actvosrdy() {}
// Go to Scale 1
PWR.d3cr().modify(|w| w.set_vos(0b11));
while !PWR.d3cr().read().vosrdy() {}
let pwr_vos = if !enable_overdrive {
VoltageScale::Scale1
} else {
critical_section::with(|_| {
RCC.apb4enr().modify(|w| w.set_syscfgen(true));
SYSCFG.pwrcr().modify(|w| w.set_oden(1));
});
while !PWR.d3cr().read().vosrdy() {}
VoltageScale::Scale0
};
// Freeze the core clocks, returning a Core Clocks Distribution
// and Reset (CCDR) structure. The actual frequency of the clocks
// configured is returned in the `clocks` member of the CCDR
// structure.
//
// Note that `freeze` will never result in a clock _faster_ than
// that specified. It may result in a clock that is a factor of [1,
// 2) slower.
//
// `syscfg` is required to enable the I/O compensation cell.
//
// # Panics
//
// If a clock specification cannot be achieved within the
// hardware specification then this function will panic. This
// function may also panic if a clock specification can be
// achieved, but the mechanism for doing so is not yet
// implemented here.
let srcclk = config.hse.unwrap_or(HSI_FREQ); // Available clocks
let (sys_ck, sys_use_pll1_p) = sys_ck_setup(&mut config, srcclk);
// Configure traceclk from PLL if needed
traceclk_setup(&mut config, sys_use_pll1_p);
// NOTE(unsafe) We have exclusive access to the RCC
let (pll1_p_ck, pll1_q_ck, pll1_r_ck) = pll::pll_setup(srcclk.0, &config.pll1, 0);
let (pll2_p_ck, pll2_q_ck, pll2_r_ck) = pll::pll_setup(srcclk.0, &config.pll2, 1);
let (pll3_p_ck, pll3_q_ck, pll3_r_ck) = pll::pll_setup(srcclk.0, &config.pll3, 2);
let sys_ck = if sys_use_pll1_p {
Hertz(unwrap!(pll1_p_ck)) // Must have been set by sys_ck_setup
} else {
sys_ck
};
// This routine does not support HSIDIV != 1. To
// do so it would need to ensure all PLLxON bits are clear
// before changing the value of HSIDIV
let cr = RCC.cr().read();
assert!(cr.hsion());
assert!(cr.hsidiv() == Hsidiv::DIV1);
RCC.csr().modify(|w| w.set_lsion(true));
while !RCC.csr().read().lsirdy() {}
// per_ck from HSI by default
let (per_ck, ckpersel) = match (config.per_ck == config.hse, config.per_ck) {
(true, Some(hse)) => (hse, Ckpersel::HSE), // HSE
(_, Some(CSI_FREQ)) => (CSI_FREQ, Ckpersel::CSI), // CSI
_ => (HSI_FREQ, Ckpersel::HSI), // HSI
};
// D1 Core Prescaler
// Set to 1
let d1cpre_bits = 0;
let d1cpre_div = 1;
let sys_d1cpre_ck = sys_ck.0 / d1cpre_div;
// Refer to part datasheet "General operating conditions"
// table for (rev V). We do not assert checks for earlier
// revisions which may have lower limits.
let (sys_d1cpre_ck_max, rcc_hclk_max, pclk_max) = match pwr_vos {
VoltageScale::Scale0 => (480_000_000, 240_000_000, 120_000_000),
VoltageScale::Scale1 => (400_000_000, 200_000_000, 100_000_000),
VoltageScale::Scale2 => (300_000_000, 150_000_000, 75_000_000),
_ => (200_000_000, 100_000_000, 50_000_000),
};
assert!(sys_d1cpre_ck <= sys_d1cpre_ck_max);
let rcc_hclk = config.hclk.map(|v| v.0).unwrap_or(sys_d1cpre_ck / 2);
assert!(rcc_hclk <= rcc_hclk_max);
// Estimate divisor
let (hpre_bits, hpre_div) = match (sys_d1cpre_ck + rcc_hclk - 1) / rcc_hclk {
0 => panic!(),
1 => (Hpre::DIV1, 1),
2 => (Hpre::DIV2, 2),
3..=5 => (Hpre::DIV4, 4),
6..=11 => (Hpre::DIV8, 8),
12..=39 => (Hpre::DIV16, 16),
40..=95 => (Hpre::DIV64, 64),
96..=191 => (Hpre::DIV128, 128),
192..=383 => (Hpre::DIV256, 256),
_ => (Hpre::DIV512, 512),
};
// Calculate real AXI and AHB clock
let rcc_hclk = sys_d1cpre_ck / hpre_div;
assert!(rcc_hclk <= rcc_hclk_max);
let rcc_aclk = rcc_hclk; // AXI clock is always equal to AHB clock on H7
// Timer prescaler selection
let timpre = Timpre::DEFAULTX2;
let requested_pclk1 = config.pclk1.map(|v| v.0).unwrap_or_else(|| pclk_max.min(rcc_hclk / 2));
let (rcc_pclk1, ppre1_bits, ppre1, rcc_timerx_ker_ck) =
ppre_calculate(requested_pclk1, rcc_hclk, pclk_max, Some(timpre));
let requested_pclk2 = config.pclk2.map(|v| v.0).unwrap_or_else(|| pclk_max.min(rcc_hclk / 2));
let (rcc_pclk2, ppre2_bits, ppre2, rcc_timery_ker_ck) =
ppre_calculate(requested_pclk2, rcc_hclk, pclk_max, Some(timpre));
let requested_pclk3 = config.pclk3.map(|v| v.0).unwrap_or_else(|| pclk_max.min(rcc_hclk / 2));
let (rcc_pclk3, ppre3_bits, ppre3, _) = ppre_calculate(requested_pclk3, rcc_hclk, pclk_max, None);
let requested_pclk4 = config.pclk4.map(|v| v.0).unwrap_or_else(|| pclk_max.min(rcc_hclk / 2));
let (rcc_pclk4, ppre4_bits, ppre4, _) = ppre_calculate(requested_pclk4, rcc_hclk, pclk_max, None);
flash_setup(rcc_aclk, pwr_vos);
// Start switching clocks -------------------
// Ensure CSI is on and stable
RCC.cr().modify(|w| w.set_csion(true));
while !RCC.cr().read().csirdy() {}
// Ensure HSI48 is on and stable
RCC.cr().modify(|w| w.set_hsi48on(true));
while !RCC.cr().read().hsi48on() {}
// XXX: support MCO ?
let hse_ck = match config.hse {
Some(hse) => {
// Ensure HSE is on and stable
RCC.cr().modify(|w| {
w.set_hseon(true);
w.set_hsebyp(config.bypass_hse);
});
while !RCC.cr().read().hserdy() {}
Some(hse)
}
None => None,
};
let pllsrc = if config.hse.is_some() { Pllsrc::HSE } else { Pllsrc::HSI };
RCC.pllckselr().modify(|w| w.set_pllsrc(pllsrc));
let enable_pll = |pll| {
RCC.cr().modify(|w| w.set_pllon(pll, true));
while !RCC.cr().read().pllrdy(pll) {}
};
if pll1_p_ck.is_some() {
enable_pll(0);
}
if pll2_p_ck.is_some() {
enable_pll(1);
}
if pll3_p_ck.is_some() {
enable_pll(2);
}
// Core Prescaler / AHB Prescaler / APB3 Prescaler
RCC.d1cfgr().modify(|w| {
w.set_d1cpre(Hpre(d1cpre_bits));
w.set_d1ppre(Dppre(ppre3_bits));
w.set_hpre(hpre_bits)
});
// Ensure core prescaler value is valid before future lower
// core voltage
while RCC.d1cfgr().read().d1cpre().0 != d1cpre_bits {}
// APB1 / APB2 Prescaler
RCC.d2cfgr().modify(|w| {
w.set_d2ppre1(Dppre(ppre1_bits));
w.set_d2ppre2(Dppre(ppre2_bits));
});
// APB4 Prescaler
RCC.d3cfgr().modify(|w| w.set_d3ppre(Dppre(ppre4_bits)));
// Peripheral Clock (per_ck)
RCC.d1ccipr().modify(|w| w.set_ckpersel(ckpersel));
// ADC clock MUX
RCC.d3ccipr().modify(|w| w.set_adcsel(config.adc_clock_source.adcsel()));
let adc_ker_ck = match config.adc_clock_source {
AdcClockSource::Pll2PCk => pll2_p_ck.map(Hertz),
AdcClockSource::Pll3RCk => pll3_r_ck.map(Hertz),
AdcClockSource::PerCk => Some(per_ck),
};
// Set timer clocks prescaler setting
RCC.cfgr().modify(|w| w.set_timpre(timpre));
// Select system clock source
let sw = match (sys_use_pll1_p, config.hse.is_some()) {
(true, _) => Sw::PLL1,
(false, true) => Sw::HSE,
_ => Sw::HSI,
};
RCC.cfgr().modify(|w| w.set_sw(sw));
while RCC.cfgr().read().sws() != sw.0 {}
// IO compensation cell - Requires CSI clock and SYSCFG
assert!(RCC.cr().read().csirdy());
RCC.apb4enr().modify(|w| w.set_syscfgen(true));
// Enable the compensation cell, using back-bias voltage code
// provide by the cell.
critical_section::with(|_| {
SYSCFG.cccsr().modify(|w| {
w.set_en(true);
w.set_cs(false);
w.set_hslv(false);
})
});
while !SYSCFG.cccsr().read().ready() {}
let core_clocks = CoreClocks {
hclk: Hertz(rcc_hclk),
pclk1: Hertz(rcc_pclk1),
pclk2: Hertz(rcc_pclk2),
pclk3: Hertz(rcc_pclk3),
pclk4: Hertz(rcc_pclk4),
ppre1,
ppre2,
ppre3,
ppre4,
csi_ck: Some(CSI_FREQ),
hsi_ck: Some(HSI_FREQ),
hsi48_ck: Some(HSI48_FREQ),
lsi_ck: Some(LSI_FREQ),
per_ck: Some(per_ck),
hse_ck,
pll1_p_ck: pll1_p_ck.map(Hertz),
pll1_q_ck: pll1_q_ck.map(Hertz),
pll1_r_ck: pll1_r_ck.map(Hertz),
pll2_p_ck: pll2_p_ck.map(Hertz),
pll2_q_ck: pll2_q_ck.map(Hertz),
pll2_r_ck: pll2_r_ck.map(Hertz),
pll3_p_ck: pll3_p_ck.map(Hertz),
pll3_q_ck: pll3_q_ck.map(Hertz),
pll3_r_ck: pll3_r_ck.map(Hertz),
timx_ker_ck: rcc_timerx_ker_ck.map(Hertz),
timy_ker_ck: rcc_timery_ker_ck.map(Hertz),
adc_ker_ck,
sys_ck,
c_ck: Hertz(sys_d1cpre_ck),
};
set_freqs(Clocks {
sys: core_clocks.c_ck,
ahb1: core_clocks.hclk,
ahb2: core_clocks.hclk,
ahb3: core_clocks.hclk,
ahb4: core_clocks.hclk,
apb1: core_clocks.pclk1,
apb2: core_clocks.pclk2,
apb4: core_clocks.pclk4,
apb1_tim: core_clocks.timx_ker_ck.unwrap_or(core_clocks.pclk1),
apb2_tim: core_clocks.timy_ker_ck.unwrap_or(core_clocks.pclk2),
adc: core_clocks.adc_ker_ck,
});
}
mod pll {
use super::{Hertz, RCC};
const VCO_MIN: u32 = 150_000_000;
const VCO_MAX: u32 = 420_000_000;
#[derive(Default)]
pub struct PllConfig {
pub p_ck: Option<Hertz>,
pub q_ck: Option<Hertz>,
pub r_ck: Option<Hertz>,
}
pub(super) struct PllConfigResults {
pub ref_x_ck: u32,
pub pll_x_m: u32,
pub pll_x_p: u32,
pub vco_ck_target: u32,
}
fn vco_output_divider_setup(output: u32, plln: usize) -> (u32, u32) {
let pll_x_p = if plln == 0 {
if output > VCO_MAX / 2 {
1
} else {
((VCO_MAX / output) | 1) - 1 // Must be even or unity
}
} else {
// Specific to PLL2/3, will subtract 1 later
if output > VCO_MAX / 2 {
1
} else {
VCO_MAX / output
}
};
let vco_ck = output + pll_x_p;
assert!(pll_x_p < 128);
assert!(vco_ck >= VCO_MIN);
assert!(vco_ck <= VCO_MAX);
(vco_ck, pll_x_p)
}
/// # Safety
///
/// Must have exclusive access to the RCC register block
unsafe fn vco_setup(pll_src: u32, requested_output: u32, plln: usize) -> PllConfigResults {
use crate::pac::rcc::vals::{Pllrge, Pllvcosel};
let (vco_ck_target, pll_x_p) = vco_output_divider_setup(requested_output, plln);
// Input divisor, resulting in a reference clock in the range
// 1 to 2 MHz. Choose the highest reference clock (lowest m)
let pll_x_m = (pll_src + 1_999_999) / 2_000_000;
assert!(pll_x_m < 64);
// Calculate resulting reference clock
let ref_x_ck = pll_src / pll_x_m;
assert!((1_000_000..=2_000_000).contains(&ref_x_ck));
RCC.pllcfgr().modify(|w| {
w.set_pllvcosel(plln, Pllvcosel::MEDIUMVCO);
w.set_pllrge(plln, Pllrge::RANGE1);
});
PllConfigResults {
ref_x_ck,
pll_x_m,
pll_x_p,
vco_ck_target,
}
}
/// # Safety
///
/// Must have exclusive access to the RCC register block
pub(super) unsafe fn pll_setup(
pll_src: u32,
config: &PllConfig,
plln: usize,
) -> (Option<u32>, Option<u32>, Option<u32>) {
use crate::pac::rcc::vals::Divp;
match config.p_ck {
Some(requested_output) => {
let config_results = vco_setup(pll_src, requested_output.0, plln);
let PllConfigResults {
ref_x_ck,
pll_x_m,
pll_x_p,
vco_ck_target,
} = config_results;
RCC.pllckselr().modify(|w| w.set_divm(plln, pll_x_m as u8));
// Feedback divider. Integer only
let pll_x_n = vco_ck_target / ref_x_ck;
assert!(pll_x_n >= 4);
assert!(pll_x_n <= 512);
RCC.plldivr(plln).modify(|w| w.set_divn1((pll_x_n - 1) as u16));
// No FRACN
RCC.pllcfgr().modify(|w| w.set_pllfracen(plln, false));
let vco_ck = ref_x_ck * pll_x_n;
RCC.plldivr(plln).modify(|w| w.set_divp1(Divp((pll_x_p - 1) as u8)));
RCC.pllcfgr().modify(|w| w.set_divpen(plln, true));
// Calulate additional output dividers
let q_ck = match config.q_ck {
Some(Hertz(ck)) if ck > 0 => {
let div = (vco_ck + ck - 1) / ck;
RCC.plldivr(plln).modify(|w| w.set_divq1((div - 1) as u8));
RCC.pllcfgr().modify(|w| w.set_divqen(plln, true));
Some(vco_ck / div)
}
_ => None,
};
let r_ck = match config.r_ck {
Some(Hertz(ck)) if ck > 0 => {
let div = (vco_ck + ck - 1) / ck;
RCC.plldivr(plln).modify(|w| w.set_divr1((div - 1) as u8));
RCC.pllcfgr().modify(|w| w.set_divren(plln, true));
Some(vco_ck / div)
}
_ => None,
};
(Some(vco_ck / pll_x_p), q_ck, r_ck)
}
None => {
assert!(
config.q_ck.is_none(),
"Must set PLL P clock for Q clock to take effect!"
);
assert!(
config.r_ck.is_none(),
"Must set PLL P clock for R clock to take effect!"
);
(None, None, None)
}
}
}
}
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