51 lines
1.9 KiB
Rust
51 lines
1.9 KiB
Rust
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#![no_std]
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#![no_main]
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#![feature(type_alias_impl_trait)]
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use defmt::info;
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use embassy_executor::Spawner;
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use embassy_nrf::interrupt;
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use embassy_nrf::pdm::{Config, Channels, Pdm, SamplerState};
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use embassy_nrf::timer::Frequency;
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use fixed::types::I7F1;
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use num_integer::Roots;
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use {defmt_rtt as _, panic_probe as _};
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// Demonstrates both continuous sampling and scanning multiple channels driven by a PPI linked timer
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#[embassy_executor::main]
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async fn main(_p: Spawner) {
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let mut p = embassy_nrf::init(Default::default());
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let mut config = Config::default();
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// Pins are correct for the onboard microphone on the Feather nRF52840 Sense.
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config.channels = Channels::Mono;
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config.gain_left = I7F1::from_bits(5); // 2.5 dB
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let mut pdm = Pdm::new(p.PDM, interrupt::take!(PDM), &mut p.P0_00, &mut p.P0_01, config);
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let mut bufs = [[0; 500]; 2];
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pdm
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.run_task_sampler(
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&mut bufs,
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move |buf| {
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// NOTE: It is important that the time spent within this callback
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// does not exceed the time taken to acquire the 1500 samples we
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// have in this example, which would be 10us + 2us per
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// sample * 1500 = 18ms. You need to measure the time taken here
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// and set the sample buffer size accordingly. Exceeding this
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// time can lead to the peripheral re-writing the other buffer.
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info!(
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"{} samples, min {=i16}, max {=i16}, RMS {=i16}",
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buf.len(),
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buf.iter().min().unwrap(),
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buf.iter().max().unwrap(),
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(
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buf.iter().map(|v| i32::from(*v).pow(2)).fold(0i32, |a,b| a.saturating_add(b))
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/ buf.len() as i32).sqrt() as i16,
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);
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SamplerState::Sampled
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},
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)
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.await;
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}
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