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85 lines
2.4 KiB
Rust
85 lines
2.4 KiB
Rust
#![no_main]
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#![no_std]
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use panic_halt;
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use stm32f0xx_hal as hal;
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use crate::hal::gpio::*;
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use crate::hal::prelude::*;
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use crate::hal::stm32;
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use cortex_m::interrupt::Mutex;
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use cortex_m::peripheral::syst::SystClkSource::Core;
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use cortex_m::peripheral::Peripherals;
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use cortex_m_rt::{entry, exception};
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use core::cell::RefCell;
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use core::ops::DerefMut;
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static GPIO: Mutex<RefCell<Option<gpioa::PA1<Output<PushPull>>>>> = Mutex::new(RefCell::new(None));
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#[entry]
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fn main() -> ! {
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if let (Some(p), Some(cp)) = (stm32::Peripherals::take(), Peripherals::take()) {
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let gpioa = p.GPIOA.split();
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let rcc = p.RCC.constrain();
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let _ = rcc.cfgr.sysclk(48.mhz()).freeze();
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let mut syst = cp.SYST;
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/* (Re-)configure PA1 as output */
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let led = gpioa.pa1.into_push_pull_output();
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cortex_m::interrupt::free(move |cs| {
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*GPIO.borrow(cs).borrow_mut() = Some(led);
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});
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/* Initialise SysTick counter with a defined value */
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unsafe { syst.cvr.write(1) };
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/* Set source for SysTick counter, here full operating frequency (== 8MHz) */
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syst.set_clock_source(Core);
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/* Set reload value, i.e. timer delay 48 MHz/4 Mcounts == 12Hz or 83ms */
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syst.set_reload(4_000_000 - 1);
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/* Start counter */
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syst.enable_counter();
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/* Start interrupt generation */
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syst.enable_interrupt();
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}
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loop {
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continue;
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}
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}
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/* Define an exception, i.e. function to call when exception occurs. Here if our SysTick timer
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* trips the flash function will be called and the specified stated passed in via argument */
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//, flash, state: u8 = 1);
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#[exception]
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fn SysTick() -> ! {
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static mut state: u8 = 1;
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/* Enter critical section */
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cortex_m::interrupt::free(|cs| {
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if let Some(ref mut led) = *GPIO.borrow(cs).borrow_mut().deref_mut() {
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/* Check state variable, keep LED off most of the time and turn it on every 10th tick */
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if *state < 10 {
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/* If set turn off the LED */
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led.set_low();
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/* And now increment state variable */
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*state += 1;
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} else {
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/* If not set, turn on the LED */
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led.set_high();
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/* And set new state variable back to 0 */
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*state = 0;
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}
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}
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});
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}
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