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Merge pull request #1667 from quentinmit/nrf-pdm

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nrf/pdm: Add continuous sampling API
This commit is contained in:
Dario Nieuwenhuis 2023-07-19 10:15:39 +00:00 committed by GitHub
commit 3382ca1a54
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GPG Key ID: 4AEE18F83AFDEB23
4 changed files with 329 additions and 19 deletions
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226
embassy-nrf/src/pdm.rs
View File

@ -8,12 +8,22 @@ use core::task::Poll;
use embassy_hal_common::drop::OnDrop;
use embassy_hal_common::{into_ref, PeripheralRef};
use fixed::types::I7F1;
use futures::future::poll_fn;
use crate::chip::EASY_DMA_SIZE;
use crate::gpio::sealed::Pin;
use crate::gpio::{AnyPin, Pin as GpioPin};
use crate::interrupt::typelevel::Interrupt;
use crate::pac::pdm::mode::{EDGE_A, OPERATION_A};
pub use crate::pac::pdm::pdmclkctrl::FREQ_A as Frequency;
#[cfg(any(
feature = "nrf52840",
feature = "nrf52833",
feature = "_nrf5340-app",
feature = "_nrf9160",
))]
pub use crate::pac::pdm::ratio::RATIO_A as Ratio;
use crate::{interrupt, Peripheral};
/// Interrupt handler.
@ -23,7 +33,20 @@ pub struct InterruptHandler<T: Instance> {
impl<T: Instance> interrupt::typelevel::Handler<T::Interrupt> for InterruptHandler<T> {
unsafe fn on_interrupt() {
T::regs().intenclr.write(|w| w.end().clear());
let r = T::regs();
if r.events_end.read().bits() != 0 {
r.intenclr.write(|w| w.end().clear());
}
if r.events_started.read().bits() != 0 {
r.intenclr.write(|w| w.started().clear());
}
if r.events_stopped.read().bits() != 0 {
r.intenclr.write(|w| w.stopped().clear());
}
T::state().waker.wake();
}
}
@ -44,10 +67,24 @@ pub enum Error {
BufferZeroLength,
/// PDM is not running
NotRunning,
/// PDM is already running
AlreadyRunning,
}
static DUMMY_BUFFER: [i16; 1] = [0; 1];
/// The state of a continuously running sampler. While it reflects
/// the progress of a sampler, it also signals what should be done
/// next. For example, if the sampler has stopped then the Pdm implementation
/// can then tear down its infrastructure.
#[derive(PartialEq)]
pub enum SamplerState {
/// The sampler processed the samples and is ready for more.
Sampled,
/// The sampler is done processing samples.
Stopped,
}
impl<'d, T: Instance> Pdm<'d, T> {
/// Create PDM driver
pub fn new(
@ -79,18 +116,24 @@ impl<'d, T: Instance> Pdm<'d, T> {
r.psel.clk.write(|w| unsafe { w.bits(clk.psel_bits()) });
// configure
// use default for
// - gain right
// - gain left
// - clk
// - ratio
r.pdmclkctrl.write(|w| w.freq().variant(config.frequency));
#[cfg(any(
feature = "nrf52840",
feature = "nrf52833",
feature = "_nrf5340-app",
feature = "_nrf9160",
))]
r.ratio.write(|w| w.ratio().variant(config.ratio));
r.mode.write(|w| {
w.edge().bit(config.edge == Edge::LeftRising);
w.operation().bit(config.operation_mode == OperationMode::Mono);
w.operation().variant(config.operation_mode.into());
w.edge().variant(config.edge.into());
w
});
r.gainl.write(|w| w.gainl().default_gain());
r.gainr.write(|w| w.gainr().default_gain());
Self::_set_gain(r, config.gain_left, config.gain_right);
// Disable all events interrupts
r.intenclr.write(|w| unsafe { w.bits(0x003F_FFFF) });
// IRQ
T::Interrupt::unpend();
@ -101,6 +144,25 @@ impl<'d, T: Instance> Pdm<'d, T> {
Self { _peri: pdm }
}
fn _set_gain(r: &crate::pac::pdm::RegisterBlock, gain_left: I7F1, gain_right: I7F1) {
let gain_left = gain_left
.saturating_add(I7F1::from_bits(40))
.saturating_to_num::<u8>()
.clamp(0, 0x50);
let gain_right = gain_right
.saturating_add(I7F1::from_bits(40))
.saturating_to_num::<u8>()
.clamp(0, 0x50);
r.gainl.write(|w| unsafe { w.gainl().bits(gain_left) });
r.gainr.write(|w| unsafe { w.gainr().bits(gain_right) });
}
/// Adjust the gain of the PDM microphone on the fly
pub fn set_gain(&mut self, gain_left: I7F1, gain_right: I7F1) {
Self::_set_gain(T::regs(), gain_left, gain_right)
}
/// Start sampling microphon data into a dummy buffer
/// Usefull to start the microphon and keep it active between recording samples
pub async fn start(&mut self) {
@ -198,6 +260,108 @@ impl<'d, T: Instance> Pdm<'d, T> {
compiler_fence(Ordering::SeqCst);
}
/// Continuous sampling with double buffers.
///
/// A sampler closure is provided that receives the buffer of samples, noting
/// that the size of this buffer can be less than the original buffer's size.
/// A command is return from the closure that indicates whether the sampling
/// should continue or stop.
///
/// NOTE: The time spent within the callback supplied should not exceed the time
/// taken to acquire the samples into a single buffer. You should measure the
/// time taken by the callback and set the sample buffer size accordingly.
/// Exceeding this time can lead to samples becoming dropped.
pub async fn run_task_sampler<S, const N: usize>(
&mut self,
bufs: &mut [[i16; N]; 2],
mut sampler: S,
) -> Result<(), Error>
where
S: FnMut(&[i16; N]) -> SamplerState,
{
let r = T::regs();
if r.events_started.read().bits() != 0 {
return Err(Error::AlreadyRunning);
}
r.sample
.ptr
.write(|w| unsafe { w.sampleptr().bits(bufs[0].as_mut_ptr() as u32) });
r.sample.maxcnt.write(|w| unsafe { w.buffsize().bits(N as _) });
// Reset and enable the events
r.events_end.reset();
r.events_started.reset();
r.events_stopped.reset();
r.intenset.write(|w| {
w.end().set();
w.started().set();
w.stopped().set();
w
});
// Don't reorder the start event before the previous writes. Hopefully self
// wouldn't happen anyway.
compiler_fence(Ordering::SeqCst);
r.tasks_start.write(|w| unsafe { w.bits(1) });
let mut current_buffer = 0;
let mut done = false;
let drop = OnDrop::new(|| {
r.tasks_stop.write(|w| unsafe { w.bits(1) });
// N.B. It would be better if this were async, but Drop only support sync code.
while r.events_stopped.read().bits() != 0 {}
});
// Wait for events and complete when the sampler indicates it has had enough.
poll_fn(|cx| {
let r = T::regs();
T::state().waker.register(cx.waker());
if r.events_end.read().bits() != 0 {
compiler_fence(Ordering::SeqCst);
r.events_end.reset();
r.intenset.write(|w| w.end().set());
if !done {
// Discard the last buffer after the user requested a stop.
if sampler(&bufs[current_buffer]) == SamplerState::Sampled {
let next_buffer = 1 - current_buffer;
current_buffer = next_buffer;
} else {
r.tasks_stop.write(|w| unsafe { w.bits(1) });
done = true;
};
};
}
if r.events_started.read().bits() != 0 {
r.events_started.reset();
r.intenset.write(|w| w.started().set());
let next_buffer = 1 - current_buffer;
r.sample
.ptr
.write(|w| unsafe { w.sampleptr().bits(bufs[next_buffer].as_mut_ptr() as u32) });
}
if r.events_stopped.read().bits() != 0 {
return Poll::Ready(());
}
Poll::Pending
})
.await;
drop.defuse();
Ok(())
}
}
/// PDM microphone driver Config
@ -206,6 +370,20 @@ pub struct Config {
pub operation_mode: OperationMode,
/// On which edge the left channel should be samples
pub edge: Edge,
/// Clock frequency
pub frequency: Frequency,
/// Clock ratio
#[cfg(any(
feature = "nrf52840",
feature = "nrf52833",
feature = "_nrf5340-app",
feature = "_nrf9160",
))]
pub ratio: Ratio,
/// Gain left in dB
pub gain_left: I7F1,
/// Gain right in dB
pub gain_right: I7F1,
}
impl Default for Config {
@ -213,6 +391,16 @@ impl Default for Config {
Self {
operation_mode: OperationMode::Mono,
edge: Edge::LeftFalling,
frequency: Frequency::DEFAULT,
#[cfg(any(
feature = "nrf52840",
feature = "nrf52833",
feature = "_nrf5340-app",
feature = "_nrf9160",
))]
ratio: Ratio::RATIO80,
gain_left: I7F1::ZERO,
gain_right: I7F1::ZERO,
}
}
}
@ -226,6 +414,15 @@ pub enum OperationMode {
Stereo,
}
impl From<OperationMode> for OPERATION_A {
fn from(mode: OperationMode) -> Self {
match mode {
OperationMode::Mono => OPERATION_A::MONO,
OperationMode::Stereo => OPERATION_A::STEREO,
}
}
}
/// PDM edge polarity
#[derive(PartialEq)]
pub enum Edge {
@ -235,6 +432,15 @@ pub enum Edge {
LeftFalling,
}
impl From<Edge> for EDGE_A {
fn from(edge: Edge) -> Self {
match edge {
Edge::LeftRising => EDGE_A::LEFT_RISING,
Edge::LeftFalling => EDGE_A::LEFT_FALLING,
}
}
}
impl<'d, T: Instance> Drop for Pdm<'d, T> {
fn drop(&mut self) {
let r = T::regs();

3
examples/nrf52840/Cargo.toml
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@ -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" }

38
examples/nrf52840/src/bin/pdm.rs
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@ -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;
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;
// 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();
const SAMPLES: usize = 2048;
let mut buf = [0i16; SAMPLES];
pdm.sample(&mut buf).await.unwrap();
info!("samples: {:?}", &buf);
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,
);
pdm.stop().await;
Timer::after(Duration::from_millis(100)).await;
info!("samples: {:?}", &buf);
pdm.stop().await;
Timer::after(Duration::from_millis(100)).await;
}
}
}

81
examples/nrf52840/src/bin/pdm_continuous.rs Normal file
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@ -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()
}