horn_driver/src/main.rs

#![no_std]
#![no_main]

// Halt on all panics. If breaking on a panic is required use `rust_begin_unwind`.
#[allow(unused_imports)]
use panic_halt;

use cortex_m_rt::entry;
use stm32l4xx_hal::{
    delay::Delay, flash::FlashExt, gpio::GpioExt, pac, prelude::*, pwr::PwrExt, rcc::RccExt,
    time::Hertz,
};

#[entry]
fn main() -> ! {
    let dp = pac::Peripherals::take().unwrap();
    let cp = cortex_m::Peripherals::take().unwrap();

    let mut flash = dp.FLASH.constrain();
    let mut rcc = dp.RCC.constrain();
    let mut pwr = dp.PWR.constrain(&mut rcc.apb1r1);

    // Ok for now, but ideally actually think about what this does (especially when we have tim).
    let clocks = rcc
        .cfgr
        .sysclk(Hertz::MHz(64))
        .pclk1(Hertz::MHz(32))
        .freeze(&mut flash.acr, &mut pwr);

    let mut gpioa = dp.GPIOA.split(&mut rcc.ahb2);
    let mut led_pin = gpioa
        .pa0
        .into_push_pull_output(&mut gpioa.moder, &mut gpioa.otyper);

    let mut timer = Delay::new(cp.SYST, clocks);

    loop {
        timer.delay_ms(1000_u32);
        led_pin.set_high();
        timer.delay_ms(1000_u32);
        led_pin.set_low();
    }
}