rust-stm32f1xx-hal-zrymod-20210426/examples/serial.rs

//! Serial interface loopback test
//!
//! You have to short the TX and RX pins to make this program work

#![deny(unsafe_code)]
#![deny(warnings)]
#![no_main]
#![no_std]

extern crate panic_halt;

use cortex_m::asm;

use nb::block;

use stm32f1xx_hal::{
    prelude::*,
    pac,
    serial::Serial,
};
use cortex_m_rt::entry;

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

    let mut flash = p.FLASH.constrain();
    let mut rcc = p.RCC.constrain();

    let clocks = rcc.cfgr.freeze(&mut flash.acr);

    let mut afio = p.AFIO.constrain(&mut rcc.apb2);

    // let mut gpioa = p.GPIOA.split(&mut rcc.apb2);
    let mut gpiob = p.GPIOB.split(&mut rcc.apb2);

    // USART1
    // let tx = gpioa.pa9.into_alternate_push_pull(&mut gpioa.crh);
    // let rx = gpioa.pa10;

    // USART1
    // let tx = gpiob.pb6.into_alternate_push_pull(&mut gpiob.crl);
    // let rx = gpiob.pb7;

    // USART2
    // let tx = gpioa.pa2.into_alternate_push_pull(&mut gpioa.crl);
    // let rx = gpioa.pa3;

    // USART3
    let tx = gpiob.pb10.into_alternate_push_pull(&mut gpiob.crh);
    let rx = gpiob.pb11;

    let serial = Serial::usart3(
        p.USART3,
        (tx, rx),
        &mut afio.mapr,
        9_600.bps(),
        clocks,
        &mut rcc.apb1,
    );

    let (mut tx, mut rx) = serial.split();

    let sent = b'X';

    block!(tx.write(sent)).ok();

    let received = block!(rx.read()).unwrap();

    assert_eq!(received, sent);

    asm::bkpt();

    loop {}
}