Set gain at runtime

2 files changed, 20 insertions, 10 deletions

diff --git a/examples/nrf/Cargo.toml b/examples/nrf/Cargo.toml
index 673bcfc6b..d0567ba8e 100644
--- a/examples/nrf/Cargo.toml
+++ b/examples/nrf/Cargo.toml
@@ -31,3 +31,4 @@ fixed = "1.10.0"
 embedded-storage = "0.3.0"
 usbd-hid = "0.5.2"
 serde = { version = "1.0.136", default-features = false }
+num-integer = { version = "0.1.45", default-features = false }
diff --git a/examples/nrf/src/bin/pdm.rs b/examples/nrf/src/bin/pdm.rs
index d5e90e27a..a73d01fb9 100644
--- a/examples/nrf/src/bin/pdm.rs
+++ b/examples/nrf/src/bin/pdm.rs
@@ -8,6 +8,7 @@ use embassy_nrf::interrupt;
 use embassy_nrf::pdm::{Config, Channels, Pdm};
 use embassy_time::{Duration, Timer};
 use fixed::types::I7F1;
+use num_integer::Roots;
 use {defmt_rtt as _, panic_probe as _};
 
 #[embassy_executor::main]
@@ -20,15 +21,23 @@ async fn main(_p: Spawner) {
     let mut pdm = Pdm::new(p.PDM, interrupt::take!(PDM), &mut p.P0_00, &mut p.P0_01, config);
 
     loop {
-        let mut buf = [0; 128];
-        pdm.sample(&mut buf).await;
-        info!(
-            "{} samples, min {=i16}, max {=i16}, mean {=i16}",
-            buf.len(),
-            buf.iter().min().unwrap(),
-            buf.iter().max().unwrap(),
-            (buf.iter().map(|v| i32::from(*v)).sum::<i32>() / buf.len() as i32) as i16,
-        );
-        Timer::after(Duration::from_millis(100)).await;
+        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));
+            for _ in 0..10 {
+                let mut buf = [0; 128];
+                pdm.sample(&mut buf).await;
+                info!(
+                    "{} samples, min {=i16}, max {=i16}, RMS {=i16}",
+                    buf.len(),
+                    buf.iter().min().unwrap(),
+                    buf.iter().max().unwrap(),
+                    (
+                        buf.iter().map(|v| i32::from(*v).pow(2)).fold(0i32, |a,b| a.saturating_add(b))
+                    / buf.len() as i32).sqrt() as i16,
+                );
+                Timer::after(Duration::from_millis(100)).await;
+            }
+        }
     }
 }