embassy/examples/stm32l4/src/bin/dac.rs

#![no_std]
#![no_main]
#![allow(incomplete_features)]
#![feature(trait_alias)]
#![feature(min_type_alias_impl_trait)]
#![feature(impl_trait_in_bindings)]
#![feature(type_alias_impl_trait)]

#[path = "../example_common.rs"]
mod example_common;

use defmt::panic;
use embassy::executor::Spawner;
use embassy_stm32::dac::{Channel, Dac, Value};
use embassy_stm32::gpio::NoPin;
use embassy_stm32::{pac, Peripherals};
use example_common::*;

#[embassy::main]
async fn main(_spawner: Spawner, p: Peripherals) {
    info!("Hello World!");

    unsafe {
        pac::DBGMCU.cr().modify(|w| {
            w.set_dbg_sleep(true);
            w.set_dbg_standby(true);
            w.set_dbg_stop(true);
        });
        pac::RCC.apb1enr1().modify(|w| {
            w.set_dac1en(true);
        });
    }

    let mut dac = Dac::new(p.DAC1, p.PA4, NoPin);

    loop {
        for v in 0..=255 {
            unwrap!(dac.set(Channel::Ch1, Value::Bit8(to_sine_wave(v))));
            unwrap!(dac.trigger(Channel::Ch1));
        }
    }
}

use micromath::F32Ext;

fn to_sine_wave(v: u8) -> u8 {
    if v >= 128 {
        // top half
        let r = 3.14 * ((v - 128) as f32 / 128.0);
        (r.sin() * 128.0 + 127.0) as u8
    } else {
        // bottom half
        let r = 3.14 + 3.14 * (v as f32 / 128.0);
        (r.sin() * 128.0 + 127.0) as u8
    }
}