Module f3::examples::_5_loopback

Serial interface loopback

#![feature(const_fn)]
#![feature(used)]
#![no_std]
 
// version = "0.2.0"
extern crate cortex_m_rt;
 
// version = "0.1.0"
#[macro_use]
extern crate cortex_m_rtfm as rtfm;
 
extern crate f3;
 
use f3::serial::Serial;
use f3::stm32f30x::interrupt::Usart1Exti25;
use f3::stm32f30x;
use rtfm::{P0, P1, T0, T1, TMax};
 
// CONFIGURATION
pub const BAUD_RATE: u32 = 115_200; // bits per second
 
// RESOURCES
peripherals!(stm32f30x, {
    GPIOA: Peripheral {
        register_block: Gpioa,
        ceiling: C0,
    },
    RCC: Peripheral {
        register_block: Rcc,
        ceiling: C0,
    },
    USART1: Peripheral {
        register_block: Usart1,
        ceiling: C1,
    },
});
 
// INITIALIZATION PHASE
fn init(ref priority: P0, threshold: &TMax) {
    let gpioa = GPIOA.access(priority, threshold);
    let rcc = RCC.access(priority, threshold);
    let usart1 = USART1.access(priority, threshold);
 
    let serial = Serial(&usart1);
 
    serial.init(&gpioa, &rcc, BAUD_RATE);
}
 
// IDLE LOOP
fn idle(_priority: P0, _threshold: T0) -> ! {
    // Sleep
    loop {
        rtfm::wfi();
    }
}
 
// TASKS
tasks!(stm32f30x, {
    loopback: Task {
        interrupt: Usart1Exti25,
        priority: P1,
        enabled: true,
    },
});
 
// Send back the received byte
fn loopback(_task: Usart1Exti25, ref priority: P1, ref threshold: T1) {
    let usart1 = USART1.access(priority, threshold);
    let serial = Serial(&usart1);
 
    if let Ok(byte) = serial.read() {
        if serial.write(byte).is_err() {
            // As we are echoing the bytes as soon as they arrive, it should
            // be impossible to have a TX buffer overrun
            #[cfg(debug_assertions)]
            unreachable!()
        }
    } else {
        // Only reachable through `rtfm::request(loopback)`
        #[cfg(debug_assertions)]
        unreachable!()
    }
}