Initial commit

src/main.rs

@@ -0,0 +1,56 @@
+//! Blinks an LED
+//!
+//! This assumes that a LED is connected to pc13 as is the case on the blue pill board.
+//!
+//! Note: Without additional hardware, PC13 should not be used to drive an LED, see page 5.1.2 of
+//! the reference manual for an explanation. This is not an issue on the blue pill.
+
+#![deny(unsafe_code)]
+#![no_std]
+#![no_main]
+
+use panic_halt as _;
+
+use nb::block;
+
+use stm32f1xx_hal::{
+    prelude::*,
+    pac,
+    timer::Timer,
+};
+use cortex_m_rt::entry;
+use embedded_hal::digital::v2::OutputPin;
+
+#[entry]
+fn main() -> ! {
+    // Get access to the core peripherals from the cortex-m crate
+    let cp = cortex_m::Peripherals::take().unwrap();
+    // Get access to the device specific peripherals from the peripheral access crate
+    let dp = pac::Peripherals::take().unwrap();
+
+    // Take ownership over the raw flash and rcc devices and convert them into the corresponding
+    // HAL structs
+    let mut flash = dp.FLASH.constrain();
+    let mut rcc = dp.RCC.constrain();
+
+    // Freeze the configuration of all the clocks in the system and store the frozen frequencies in
+    // `clocks`
+    let clocks = rcc.cfgr.freeze(&mut flash.acr);
+
+    // Acquire the GPIOC peripheral
+    let mut gpioc = dp.GPIOC.split(&mut rcc.apb2);
+
+    // Configure gpio C pin 13 as a push-pull output. The `crh` register is passed to the function
+    // in order to configure the port. For pins 0-7, crl should be passed instead.
+    let mut led = gpioc.pc13.into_push_pull_output(&mut gpioc.crh);
+    // Configure the syst timer to trigger an update every second
+    let mut timer = Timer::syst(cp.SYST, &clocks).start_count_down(1.hz());
+
+    // Wait for the timer to trigger an update and change the state of the LED
+    loop {
+        block!(timer.wait()).unwrap();
+        led.set_high().unwrap();
+        block!(timer.wait()).unwrap();
+        led.set_low().unwrap();
+    }
+}