[WIP/RFC] Improve GPIO API

CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [Unreleased]
 
+### Added
+
+- Add runtime-reconfigurable GPIO pins
+
 ### Fixed
 
 - Fix period retrieval for timers

examples/dynamic_gpio.rs

@@ -0,0 +1,49 @@
+#![deny(unsafe_code)]
+#![no_std]
+#![no_main]
+
+use panic_halt as _;
+
+use nb::block;
+
+use cortex_m_rt::entry;
+use cortex_m_semihosting::hprintln;
+use embedded_hal::digital::v2::{InputPin, OutputPin};
+use stm32f1xx_hal::{pac, prelude::*, timer::Timer};
+
+#[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);
+
+    let mut pin = gpioc.pc13.into_dynamic(&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 {
+        pin.make_floating_input(&mut gpioc.crh);
+        block!(timer.wait()).unwrap();
+        hprintln!("{}", pin.is_high().unwrap()).unwrap();
+
+        pin.make_push_pull_output(&mut gpioc.crh);
+        pin.set_high().unwrap();
+        block!(timer.wait()).unwrap();
+        pin.set_low().unwrap();
+        block!(timer.wait()).unwrap();
+    }
+}

examples/multi_mode_gpio.rs

@@ -0,0 +1,53 @@
+#![deny(unsafe_code)]
+#![no_std]
+#![no_main]
+
+use panic_halt as _;
+
+use nb::block;
+
+use cortex_m_rt::entry;
+use cortex_m_semihosting::hprintln;
+use embedded_hal::digital::v2::{InputPin, OutputPin};
+use stm32f1xx_hal::{gpio::State, pac, prelude::*, timer::Timer};
+
+#[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);
+
+    let mut pin = gpioc.pc13.into_floating_input(&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();
+        hprintln!("{}", pin.is_high().unwrap()).unwrap();
+        pin.as_push_pull_output(&mut gpioc.crh, |out| {
+            out.set_high().unwrap();
+            block!(timer.wait()).unwrap();
+            out.set_low().unwrap();
+            block!(timer.wait()).unwrap();
+        });
+        pin.as_push_pull_output_with_state(&mut gpioc.crh, State::High, |out| {
+            block!(timer.wait()).unwrap();
+            out.set_low().unwrap();
+            block!(timer.wait()).unwrap();
+        });
+    }
+}