Module f3::examples::_6_concurrency

LED roulette and serial loopback running concurrently

#![feature(const_fn)]
#![feature(used)]
#![no_std]
 
// version = "0.2.2", default-features = false
extern crate cast;
 
// 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 cast::{u8, usize};
use f3::led::{self, LEDS};
use f3::serial::Serial;
use f3::stm32f30x::interrupt::{Tim7, Usart1Exti25};
use f3::stm32f30x;
use f3::timer::Timer;
use rtfm::{Local, P0, P1, T0, T1, TMax};
 
// CONFIGURATION
pub const BAUD_RATE: u32 = 115_200; // bits per second
const FREQUENCY: u32 = 4; // Hz
 
// RESOURCES
peripherals!(stm32f30x, {
    GPIOA: Peripheral {
        register_block: Gpioa,
        ceiling: C0,
    },
    GPIOE: Peripheral {
        register_block: Gpioe,
        ceiling: C0,
    },
    RCC: Peripheral {
        register_block: Rcc,
        ceiling: C0,
    },
    TIM7: Peripheral {
        register_block: Tim7,
        ceiling: C1,
    },
    USART1: Peripheral {
        register_block: Usart1,
        ceiling: C1,
    },
});
 
// INITIALIZATION PHASE
fn init(ref priority: P0, threshold: &TMax) {
    let gpioa = GPIOA.access(priority, threshold);
    let gpioe = GPIOE.access(priority, threshold);
    let rcc = RCC.access(priority, threshold);
    let tim7 = TIM7.access(priority, threshold);
    let usart1 = USART1.access(priority, threshold);
 
    let timer = Timer(&tim7);
    let serial = Serial(&usart1);
 
    led::init(&gpioe, &rcc);
    timer.init(&rcc, FREQUENCY);
    serial.init(&gpioa, &rcc, BAUD_RATE);
 
    timer.resume();
}
 
// IDLE LOOP
fn idle(_priority: P0, _threshold: T0) -> ! {
    // Sleep
    loop {
        rtfm::wfi();
    }
}
 
// TASKS
tasks!(stm32f30x, {
    loopback: Task {
        interrupt: Usart1Exti25,
        priority: P1,
        enabled: true,
    },
    roulette: Task {
        interrupt: Tim7,
        priority: P1,
        enabled: true,
    },
});
 
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!()
    }
}
 
fn roulette(mut task: Tim7, ref priority: P1, ref threshold: T1) {
    static STATE: Local<u8, Tim7> = Local::new(0);
 
    let tim7 = TIM7.access(priority, threshold);
    let timer = Timer(&tim7);
 
    if timer.clear_update_flag().is_ok() {
        let state = STATE.borrow_mut(&mut task);
 
        let curr = *state;
        let next = (curr + 1) % u8(LEDS.len()).unwrap();
 
        LEDS[usize(curr)].off();
        LEDS[usize(next)].on();
 
        *state = next;
    } else {
        // Only reachable through `rtfm::request(roulette)`
        #[cfg(debug_assertion)]
        unreachable!()
    }
}