Add example of GPIO input mode

Cargo.toml

@@ -146,3 +146,7 @@ required-features = ["has-can"]
 [[example]]
 name = "can-rtic"
 required-features = ["has-can", "rt"]
+
+[[example]]
+name = "gpio_input"
+required-features = ["stm32f103"]

examples/gpio_input.rs

@@ -0,0 +1,73 @@
+//! Through buttons to control the LED.
+//!
+//! This assumes that has two LEDs, the red light is connected to pa8 and the green light is connected to pd2.
+//!
+//! Meanwhile, it has two buttons, we can call them key_0 and key_1.
+//! The key_0 is connected to pc5, and the key_1 is connected to pa15.
+//!
+//! We need to set into_pull_up_input for pc5 and pa15, for the reason that the key_0 and key_1 were connected to GND.
+//!
+//! Use key_0 to control the red light, key_1 to control the green light.
+//! Only press a button after releasing the button to turns on the led, again turns down the led.
+//!
+//! And the long press was a nullity.
+
+#![deny(unsafe_code)]
+#![no_std]
+#![no_main]
+use cortex_m_rt::entry;
+use embedded_hal::digital::v2::InputPin;
+use panic_halt as _;
+use stm32f1xx_hal::{delay::Delay, pac, prelude::*};
+
+#[entry]
+fn main() -> ! {
+    let dp = pac::Peripherals::take().unwrap();
+    let cp = cortex_m::Peripherals::take().unwrap();
+
+    let mut flash = dp.FLASH.constrain();
+    let mut rcc = dp.RCC.constrain();
+
+    let clock = rcc.cfgr.freeze(&mut flash.acr);
+
+    let mut gpioa = dp.GPIOA.split(&mut rcc.apb2);
+    let mut _gpiob = dp.GPIOB.split(&mut rcc.apb2);
+    let mut gpioc = dp.GPIOC.split(&mut rcc.apb2);
+    let mut gpiod = dp.GPIOD.split(&mut rcc.apb2);
+
+    // red_led and green_led
+    let mut red_led = gpioa
+        .pa8
+        .into_push_pull_output_with_state(&mut gpioa.crh, stm32f1xx_hal::gpio::State::High);
+    let mut green_led = gpiod
+        .pd2
+        .into_push_pull_output_with_state(&mut gpiod.crl, stm32f1xx_hal::gpio::State::High);
+
+    let mut afio = dp.AFIO.constrain(&mut rcc.apb2);
+    let (gpioa_pa15, _gpiob_pb3, _gpiob_pb4) =
+        afio.mapr.disable_jtag(gpioa.pa15, _gpiob.pb3, _gpiob.pb4);
+
+    // key_0 and key_1
+    let key_0 = gpioc.pc5.into_pull_up_input(&mut gpioc.crl);
+    let key_1 = gpioa_pa15.into_pull_up_input(&mut gpioa.crh);
+
+    // The key_up for check buttons if long press.
+    // if key_up is true, and buttons were not long press.
+    let mut key_up: bool = true;
+    let mut delay = Delay::new(cp.SYST, clock);
+    loop {
+        let key_result = (key_0.is_low().unwrap(), key_1.is_low().unwrap());
+        if key_up && (key_result.0 || key_result.1) {
+            key_up = false;
+            delay.delay_ms(10u8);
+            match key_result {
+                (x, _) if x == true => red_led.toggle().unwrap(),
+                (_, y) if y == true => green_led.toggle().unwrap(),
+                (_, _) => (),
+            }
+        } else if !key_result.0 && !key_result.1 {
+            key_up = true;
+            delay.delay_ms(10u8);
+        }
+    }
+}