refactor for streamlining

tutorial/07-button-input/src/main.rs

@@ -0,0 +1,33 @@
+#![no_std]
+#![no_main]
+
+use cortex_m_rt::entry;
+use defmt::info;
+use nb::block;
+use stm32f1xx_hal::{pac, prelude::*, timer::Timer};
+use {defmt_rtt as _, panic_probe as _};
+
+#[entry]
+fn main() -> ! {
+    let cp = cortex_m::Peripherals::take().unwrap();
+    let dp = pac::Peripherals::take().unwrap();
+
+    let mut rcc = dp.RCC.constrain();
+    let mut gpioa = dp.GPIOA.split(&mut rcc);
+
+    // TODO: Button wiring: PA0 -> button -> GND
+
+    let mut timer = Timer::syst(cp.SYST, &rcc.clocks).counter_hz();
+    timer.start(40.Hz()).unwrap();
+
+    let mut last_pressed = false;
+
+    loop {
+        
+        // TODO: get the current button status
+        // TODO: print a message when the button is pressed and released
+
+        // Poll at 25ms to avoid too much log spam.
+        block!(timer.wait()).unwrap();
+    }
+}