rp: Add PWM input example

examples/rp/src/bin/pwm_input.rs

@@ -0,0 +1,26 @@
+//! This example shows how to use the PWM module to measure the frequency of an input signal.
+
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+use defmt::*;
+use embassy_executor::Spawner;
+use embassy_rp::pwm::{Config, InputMode, Pwm};
+use embassy_time::{Duration, Ticker};
+use {defmt_rtt as _, panic_probe as _};
+
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) {
+    let p = embassy_rp::init(Default::default());
+
+    let mut cfg: Config = Default::default();
+    let mut pwm = Pwm::new_input(p.PWM_CH2, p.PIN_5, InputMode::RisingEdge, cfg);
+
+    let mut ticker = Ticker::every(Duration::from_secs(1));
+    loop {
+        info!("Input frequency: {} Hz", pwm.counter());
+        pwm.set_counter(0);
+        ticker.next().await;
+    }
+}