Added support for Input Capture timer mode for frequency and pulse duration measurement

Author: Nilolay

CHANGELOG.md

@@ -15,6 +15,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
  - Use `write` instead of `modify` to clear flags [#829]
  - Bump `stm32f4-staging` to 0.18, update other dependencies [#831]
  - `serial` mod refactor [#833] [#839]
+ - Add "capture" support for timers [#830]
  - FMPI2c APB timings [#770]
  - Fefactor FMPI2c `embedded-hal` implementations [#784]
  - remove `NoPin`, use `Option` instead [#813]
@@ -23,6 +24,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 [#784]: https://github.com/stm32-rs/stm32f4xx-hal/pull/784
 [#813]: https://github.com/stm32-rs/stm32f4xx-hal/pull/813
 [#829]: https://github.com/stm32-rs/stm32f4xx-hal/pull/829
+[#830]: https://github.com/stm32-rs/stm32f4xx-hal/pull/830
 [#831]: https://github.com/stm32-rs/stm32f4xx-hal/pull/831
 [#832]: https://github.com/stm32-rs/stm32f4xx-hal/pull/832
 [#833]: https://github.com/stm32-rs/stm32f4xx-hal/pull/833

Cargo.toml

@@ -781,3 +781,7 @@ required-features = []
 [[example]]
 name = "fmc-sdram"
 required-features = ["stm32f469", "stm32-fmc"]
+
+[[example]]
+name = "rtic2-timer-input-capture"
+required-features = ["rtic2"]

examples/rtic2-timer-input-capture.rs

@@ -0,0 +1,78 @@
+#![no_main]
+#![no_std]
+
+use defmt_rtt as _;
+use panic_probe as _;
+use stm32f4xx_hal::{
+    pac,
+    pac::{TIM2, TIM5},
+    prelude::*,
+    timer::{CaptureChannel, CaptureHzManager, CapturePolarity, Event, Flag, PwmChannel, Timer},
+};
+
+use rtic::app;
+
+#[app(device = pac, dispatchers = [USART1], peripherals = true)]
+mod app {
+    use super::*;
+
+    #[shared]
+    struct Shared {}
+
+    #[local]
+    struct Local {
+        tim5: CaptureHzManager<TIM5>,
+        ch1: CaptureChannel<TIM5, 0>,
+    }
+
+    #[init]
+    fn init(ctx: init::Context) -> (Shared, Local) {
+        let dp = ctx.device;
+        let rcc = dp.RCC.constrain();
+        let clocks = rcc.cfgr.sysclk(48.MHz()).freeze();
+        let gpioa = dp.GPIOA.split();
+
+        // Configuration of TIM2 in PWM mode
+        let timer = Timer::new(dp.TIM2, &clocks);
+        let (_, (ch1, ..)) = timer.pwm_hz(893.Hz());
+        let mut tim_2: PwmChannel<TIM2, 0> = ch1.with(gpioa.pa5);
+        tim_2.set_duty(50);
+        tim_2.enable();
+
+        // It is necessary to connect pins PA0 and PA5 through a resistor of 1 kΩ - 10 kΩ
+
+        // Configuration of TIM5 in input capture mode
+        let (mut tim5, (ch1, ..)) = Timer::new(dp.TIM5, &clocks).capture_hz(48.MHz());
+        let mut ch1 = ch1.with(gpioa.pa0);
+        tim5.listen(Event::C1);
+
+        ch1.set_polarity(CapturePolarity::ActiveHigh);
+        ch1.enable();
+
+        defmt::info!("Start");
+
+        (Shared {}, Local { tim5, ch1 })
+    }
+
+    #[task(binds = TIM5, local = [tim5, ch1, prev_capture: u32 = 0], priority = 3)]
+    fn tim5_interrupt(cx: tim5_interrupt::Context) {
+        if cx.local.tim5.flags().contains(Flag::C1) {
+            let timer_clock = cx.local.tim5.get_timer_clock();
+            let max_auto_reload = cx.local.tim5.get_max_auto_reload();
+            let current_capture = cx.local.ch1.get_capture();
+
+            let delta = if current_capture >= *cx.local.prev_capture {
+                current_capture - *cx.local.prev_capture
+            } else {
+                (max_auto_reload - *cx.local.prev_capture) + current_capture
+            };
+
+            let freq = timer_clock as f32 / delta as f32;
+
+            defmt::info!("Freq: {} Hz", freq); // Output = Freq: 893.00665 Hz
+
+            *cx.local.prev_capture = current_capture;
+            cx.local.tim5.clear_flags(Flag::C1);
+        }
+    }
+}