My first blinky with Rust embedded

main.rs

#![no_std]
#![no_main]

use panic_halt as _; // you can put a breakpoint on `rust_begin_unwind` to catch panics
use cortex_m_rt::entry;
use stm32f4xx_hal as hal;

use crate::hal::{prelude::*, stm32};

#[entry]
fn main() -> ! {

    loop {

        if let (Some(dp), Some(cp)) = (
            stm32::Peripherals::take(),
            cortex_m::peripheral::Peripherals::take(),
        ) {
            let gpiod = dp.GPIOD.split();
            let mut led1 = gpiod.pd13.into_push_pull_output();
            let mut led2 = gpiod.pd12.into_push_pull_output();
            let mut led3 = gpiod.pd14.into_push_pull_output();
            let mut led4 = gpiod.pd15.into_push_pull_output();

            // Set up the system clock. We want to run at 48MHz for this one.
            let rcc = dp.RCC.constrain();
            let clocks = rcc.cfgr.sysclk(48.mhz()).freeze();

            // Create a delay abstraction based on SysTick
            let mut delay = hal::delay::Delay::new(cp.SYST, clocks);

            let ms_delay = 300_u32;
            loop {
                led1.set_high().unwrap();
                delay.delay_ms(ms_delay);
                led1.set_low().unwrap();
                led2.set_high().unwrap();
                delay.delay_ms(ms_delay);
                led2.set_low().unwrap();
                led3.set_high().unwrap();
                delay.delay_ms(ms_delay);
                led3.set_low().unwrap();
                led4.set_high().unwrap();
                delay.delay_ms(ms_delay);
                led4.set_low().unwrap();
            }
        }

    }
}