py32-hal 0.4.0

// The following code is modified from embassy-stm32
// https://github.com/embassy-rs/embassy/tree/main/embassy-stm32
// Special thanks to the Embassy Project and its contributors for their work!

use embassy_hal_internal::into_ref;

use super::blocking_delay_us;
use crate::adc::{Adc, AdcChannel, Instance, Resolution, SampleTime};
use crate::pac::adc::vals::Extsel;
use crate::pac::RCC;
use crate::peripherals::ADC1;
use crate::time::Hertz;
use crate::{rcc, Peripheral};

mod ringbuffered_v2;
pub use ringbuffered_v2::{RingBufferedAdc, Sequence};

/// Default VREF voltage used for sample conversion to millivolts.
pub const VREF_DEFAULT_MV: u32 = 3300;
/// VREF voltage used for factory calibration of VREFINTCAL register.
pub const VREF_CALIB_MV: u32 = 3300;

pub struct VrefInt;
impl AdcChannel<ADC1> for VrefInt {}
impl super::SealedAdcChannel<ADC1> for VrefInt {
    fn channel(&self) -> u8 {
        17
    }
}

impl VrefInt {
    /// Time needed for internal voltage reference to stabilize
    pub fn start_time_us() -> u32 {
        10
    }
}

pub struct Temperature;
impl AdcChannel<ADC1> for Temperature {}
impl super::SealedAdcChannel<ADC1> for Temperature {
    fn channel(&self) -> u8 {
        16
    }
}

impl Temperature {
    /// Time needed for temperature sensor readings to stabilize
    pub fn start_time_us() -> u32 {
        10
    }
}

// pub struct Vbat;
// impl AdcChannel<ADC1> for Vbat {}
// impl super::SealedAdcChannel<ADC1> for Vbat {
//     fn channel(&self) -> u8 {
//         18
//     }
// }

pub enum Prescaler {
    Div2,
    Div4,
    Div6,
    Div8,
}

impl Prescaler {
    fn from_pclk(freq: Hertz) -> Self {
        #[cfg(py32f072)]
        const MAX_FREQUENCY: Hertz = Hertz(16_000_000);
        let raw_div = freq.0 / MAX_FREQUENCY.0;
        match raw_div {
            0..=1 => Self::Div2,
            2..=3 => Self::Div4,
            4..=5 => Self::Div6,
            6..=7 => Self::Div8,
            _ => panic!(
                "Selected PCLK frequency is too high for ADC with largest possible prescaler."
            ),
        }
    }

    fn adcdiv(&self) -> crate::pac::rcc::vals::Adcdiv {
        match self {
            Prescaler::Div2 => crate::pac::rcc::vals::Adcdiv::DIV2,
            Prescaler::Div4 => crate::pac::rcc::vals::Adcdiv::DIV4,
            Prescaler::Div6 => crate::pac::rcc::vals::Adcdiv::DIV6,
            Prescaler::Div8 => crate::pac::rcc::vals::Adcdiv::DIV8,
        }
    }
}

impl<'d, T> Adc<'d, T>
where
    T: Instance,
{
    pub fn new(adc: impl Peripheral<P = T> + 'd) -> Self {
        let presc = Prescaler::from_pclk(T::frequency());
        Self::new_with_prediv(adc, presc)
    }

    /// adc_div: The PCLK division factor
    pub fn new_with_prediv(adc: impl Peripheral<P = T> + 'd, adc_div: Prescaler) -> Self {
        into_ref!(adc);
        rcc::enable_and_reset::<T>();

        RCC.cr().modify(|reg| {
            reg.set_adcdiv(adc_div.adcdiv());
        });
        T::regs().cr2().modify(|reg| {
            reg.set_extsel(Extsel::SWSTART);
        });

        Self::calibrate();

        T::regs().cr2().modify(|reg| {
            reg.set_adon(true);
        });

        blocking_delay_us(3);

        Self {
            adc,
            sample_time: SampleTime::from_bits(0),
        }
    }

    pub fn set_sample_time(&mut self, sample_time: SampleTime) {
        self.sample_time = sample_time;
    }

    pub fn set_resolution(&mut self, resolution: Resolution) {
        T::regs().cr1().modify(|reg| reg.set_res(resolution.into()));
    }

    /// Enables internal voltage reference and returns [VrefInt], which can be used in
    /// [Adc::read_internal()] to perform conversion.
    pub fn enable_vrefint(&self) -> VrefInt {
        T::regs().cr2().modify(|reg| {
            reg.set_tsvrefe(true);
        });

        VrefInt {}
    }

    /// Enables internal temperature sensor and returns [Temperature], which can be used in
    /// [Adc::read_internal()] to perform conversion.
    ///
    /// On STM32F42 and STM32F43 this can not be used together with [Vbat]. If both are enabled,
    /// temperature sensor will return vbat value.
    pub fn enable_temperature(&self) -> Temperature {
        T::regs().cr2().modify(|reg| {
            reg.set_tsvrefe(true);
        });

        Temperature {}
    }

    // /// Enables vbat input and returns [Vbat], which can be used in
    // /// [Adc::read_internal()] to perform conversion.
    // pub fn enable_vbat(&self) -> Vbat {
    //     T::common_regs().ccr().modify(|reg| {
    //         reg.set_vbate(true);
    //     });

    //     Vbat {}
    // }

    /// Perform a single conversion.
    fn convert(&mut self) -> u16 {
        // clear end of conversion flag
        T::regs().sr().modify(|reg| {
            reg.set_eoc(false);
        });

        // Start conversion
        T::regs().cr2().modify(|reg| {
            reg.set_swstart(true);
            reg.set_exttrig(true);
        });

        while T::regs().sr().read().strt() == false {
            // spin //wait for actual start
        }
        while T::regs().sr().read().eoc() == false {
            // spin //wait for finish
        }

        T::regs().dr().read().0 as u16
    }

    pub fn blocking_read(&mut self, channel: &mut impl AdcChannel<T>) -> u16 {
        channel.setup();

        // Configure ADC
        let channel = channel.channel();

        // Select channel
        T::regs().sqr3().write(|reg| reg.set_sq(0, channel));

        // Configure channel
        Self::set_channel_sample_time(channel, self.sample_time);

        self.convert()
    }

    fn set_channel_sample_time(ch: u8, sample_time: SampleTime) {
        let sample_time = sample_time.into();
        match ch {
            ..=9 => T::regs()
                .smpr3()
                .modify(|reg| reg.set_smp(ch as _, sample_time)),
            ..=19 => T::regs()
                .smpr2()
                .modify(|reg| reg.set_smp((ch - 10) as _, sample_time)),
            _ => T::regs()
                .smpr3()
                .modify(|reg| reg.set_smp((ch - 20) as _, sample_time)),
        }
    }

    /// Perform ADC automatic self-calibration
    pub fn calibrate() {
        T::regs().cr2().modify(|reg| {
            reg.set_adon(false);
        });

        while T::regs().cr2().read().adon() {}

        // Wait for ADC to be fully disabled
        // Compute and wait for required ADC clock cycles

        let adc_clock_mhz = 72_u32; // MAX
        let cpu_clock_mhz = unsafe { rcc::get_freqs() }.sys.to_hertz().unwrap().0 / 1_000_000;
        #[cfg(py32f072)]
        let precalibration_cycles = 2_u32;

        let delay_us = (precalibration_cycles * adc_clock_mhz) / cpu_clock_mhz;
        blocking_delay_us(delay_us);

        // Check if ADC is enabled
        if T::regs().cr2().read().adon() {
            panic!();
        }

        // Reset calibration
        T::regs().cr2().modify(|reg| {
            reg.set_rstcal(true);
        });

        // Wait for calibration reset to complete
        while T::regs().cr2().read().rstcal() {}

        // Start calibration
        T::regs().cr2().modify(|reg| {
            reg.set_cal(true);
        });

        // Wait for calibration to complete
        while T::regs().cr2().read().cal() {}
    }
}

impl<'d, T: Instance> Drop for Adc<'d, T> {
    fn drop(&mut self) {
        T::regs().cr2().modify(|reg| {
            reg.set_adon(false);
        });

        rcc::disable::<T>();
    }
}