Merge branch 'main' of https://github.com/embassy-rs/embassy into mac

3 files changed, 117 insertions, 13 deletions

diff --git a/examples/nrf52840/Cargo.toml b/examples/nrf52840/Cargo.toml
index 7b9c371bb..9b41ec5ab 100644
--- a/examples/nrf52840/Cargo.toml
+++ b/examples/nrf52840/Cargo.toml
@@ -43,6 +43,7 @@ embassy-net-esp-hosted = { version = "0.1.0", path = "../../embassy-net-esp-host
 defmt = "0.3"
 defmt-rtt = "0.4"
 
+fixed = "1.10.0"
 static_cell = "1.1"
 cortex-m = { version = "0.7.6", features = ["inline-asm", "critical-section-single-core"] }
 cortex-m-rt = "0.7.0"
@@ -53,6 +54,8 @@ embedded-storage = "0.3.0"
 usbd-hid = "0.6.0"
 serde = { version = "1.0.136", default-features = false }
 embedded-hal-async = { version = "0.2.0-alpha.2", optional = true }
+num-integer = { version = "0.1.45", default-features = false }
+microfft = "0.5.0"
 
 [patch.crates-io]
 lora-phy = { git = "https://github.com/embassy-rs/lora-phy", rev = "ad289428fd44b02788e2fa2116445cc8f640a265" }
diff --git a/examples/nrf52840/src/bin/pdm.rs b/examples/nrf52840/src/bin/pdm.rs
index 6b41320ca..444b9137f 100644
--- a/examples/nrf52840/src/bin/pdm.rs
+++ b/examples/nrf52840/src/bin/pdm.rs
@@ -7,6 +7,8 @@ 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 {
@@ -20,18 +22,36 @@ async fn main(_p: Spawner) {
     let mut pdm = Pdm::new(p.PDM, Irqs, p.P0_01, p.P0_00, config);
 
     loop {
-        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();
-
-        info!("samples: {:?}", &buf);
-
-        pdm.stop().await;
-        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));
+            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;
+        }
     }
 }
diff --git a/examples/nrf52840/src/bin/pdm_continuous.rs b/examples/nrf52840/src/bin/pdm_continuous.rs
new file mode 100644
index 000000000..7d8531475
--- /dev/null
+++ b/examples/nrf52840/src/bin/pdm_continuous.rs
@@ -0,0 +1,81 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+use core::cmp::Ordering;
+
+use defmt::info;
+use embassy_executor::Spawner;
+use embassy_nrf::pdm::{self, Config, Frequency, OperationMode, Pdm, Ratio, SamplerState};
+use embassy_nrf::{bind_interrupts, peripherals};
+use fixed::types::I7F1;
+use microfft::real::rfft_1024;
+use num_integer::Roots;
+use {defmt_rtt as _, panic_probe as _};
+
+// Demonstrates both continuous sampling and scanning multiple channels driven by a PPI linked timer
+
+bind_interrupts!(struct Irqs {
+    PDM => pdm::InterruptHandler<peripherals::PDM>;
+});
+
+#[embassy_executor::main]
+async fn main(_p: Spawner) {
+    let mut p = embassy_nrf::init(Default::default());
+    let mut config = Config::default();
+    // Pins are correct for the onboard microphone on the Feather nRF52840 Sense.
+    config.frequency = Frequency::_1280K; // 16 kHz sample rate
+    config.ratio = Ratio::RATIO80;
+    config.operation_mode = OperationMode::Mono;
+    config.gain_left = I7F1::from_bits(5); // 2.5 dB
+    let mut pdm = Pdm::new(p.PDM, Irqs, &mut p.P0_00, &mut p.P0_01, config);
+
+    let mut bufs = [[0; 1024]; 2];
+
+    pdm.run_task_sampler(&mut bufs, move |buf| {
+        // NOTE: It is important that the time spent within this callback
+        // does not exceed the time taken to acquire the 1500 samples we
+        // have in this example, which would be 10us + 2us per
+        // sample * 1500 = 18ms. You need to measure the time taken here
+        // and set the sample buffer size accordingly. Exceeding this
+        // time can lead to the peripheral re-writing the other buffer.
+        let mean = (buf.iter().map(|v| i32::from(*v)).sum::<i32>() / buf.len() as i32) as i16;
+        let (peak_freq_index, peak_mag) = fft_peak_freq(&buf);
+        let peak_freq = peak_freq_index * 16000 / buf.len();
+        info!(
+            "{} samples, min {=i16}, max {=i16}, mean {=i16}, AC RMS {=i16}, peak {} @ {} Hz",
+            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,
+            peak_mag,
+            peak_freq,
+        );
+        SamplerState::Sampled
+    })
+    .await
+    .unwrap();
+}
+
+fn fft_peak_freq(input: &[i16; 1024]) -> (usize, u32) {
+    let mut f = [0f32; 1024];
+    for i in 0..input.len() {
+        f[i] = (input[i] as f32) / 32768.0;
+    }
+    // N.B. rfft_1024 does the FFT in-place so result is actually also a reference to f.
+    let result = rfft_1024(&mut f);
+    result[0].im = 0.0;
+
+    result
+        .iter()
+        .map(|c| c.norm_sqr())
+        .enumerate()
+        .max_by(|(_, a), (_, b)| a.partial_cmp(b).unwrap_or(Ordering::Equal))
+        .map(|(i, v)| (i, ((v * 32768.0) as u32).sqrt()))
+        .unwrap()
+}