Merge remote-tracking branch 'origin/main' into nrf-pdm

examples/nrf52840/src/bin/pdm.rs

@@ -0,0 +1,55 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+use defmt::info;
+use embassy_executor::Spawner;
+use embassy_nrf::pdm::{self, Config, Pdm};
+use embassy_nrf::{bind_interrupts, peripherals};
+use embassy_time::{Duration, Timer};
+use fixed::types::I7F1;
+use num_integer::Roots;
+use {defmt_rtt as _, panic_probe as _};
+
+bind_interrupts!(struct Irqs {
+    PDM => pdm::InterruptHandler<peripherals::PDM>;
+});
+
+#[embassy_executor::main]
+async fn main(_p: Spawner) {
+    let p = embassy_nrf::init(Default::default());
+    let config = Config::default();
+    let mut pdm = Pdm::new(p.PDM, Irqs, p.P0_01, p.P0_00, config);
+
+    loop {
+        for gain in [I7F1::from_num(-20), I7F1::from_num(0), I7F1::from_num(20)] {
+            pdm.set_gain(gain, gain);
+            info!("Gain = {} dB", defmt::Debug2Format(&gain));
+            pdm.start().await;
+
+            // wait some time till the microphon settled
+            Timer::after(Duration::from_millis(1000)).await;
+
+            const SAMPLES: usize = 2048;
+            let mut buf = [0i16; SAMPLES];
+            pdm.sample(&mut buf).await.unwrap();
+
+            let mean = (buf.iter().map(|v| i32::from(*v)).sum::<i32>() / buf.len() as i32) as i16;
+            info!(
+                "{} samples, min {=i16}, max {=i16}, mean {=i16}, AC RMS {=i16}",
+                buf.len(),
+                buf.iter().min().unwrap(),
+                buf.iter().max().unwrap(),
+                mean,
+                (
+                    buf.iter().map(|v| i32::from(*v - mean).pow(2)).fold(0i32, |a,b| a.saturating_add(b))
+                / buf.len() as i32).sqrt() as i16,
+            );
+
+            info!("samples: {:?}", &buf);
+
+            pdm.stop().await;
+            Timer::after(Duration::from_millis(100)).await;
+        }
+    }
+}