49 lines
1.4 KiB
Rust
49 lines
1.4 KiB
Rust
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// Example inspired by RTIC's I2S demo: https://github.com/nrf-rs/nrf-hal/blob/master/examples/i2s-controller-demo/src/main.rs
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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::*;
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use embassy_executor::Spawner;
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use embassy_nrf::{i2s};
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use {defmt_rtt as _, panic_probe as _};
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#[repr(align(4))]
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pub struct Aligned<T: ?Sized>(T);
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#[embassy_executor::main]
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async fn main(_spawner: Spawner) {
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let p = embassy_nrf::init(Default::default());
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let config = i2s::Config::default();
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let mut i2s = i2s::I2s::new(p.I2S, p.P0_28, p.P0_29, p.P0_31, p.P0_11, p.P0_30, config);
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let mut signal_buf: Aligned<[i16; 32]> = Aligned([0i16; 32]);
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let len = signal_buf.0.len() / 2;
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for x in 0..len {
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signal_buf.0[2 * x] = triangle_wave(x as i32, len, 2048, 0, 1) as i16;
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signal_buf.0[2 * x + 1] = triangle_wave(x as i32, len, 2048, 0, 1) as i16;
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}
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let ptr = &signal_buf.0 as *const i16 as *const u8;
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let len = signal_buf.0.len() * core::mem::size_of::<i16>();
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i2s.start();
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i2s.set_tx_enabled(true);
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loop {
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i2s.tx(ptr, len).await;
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}
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}
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fn triangle_wave(x: i32, length: usize, amplitude: i32, phase: i32, periods: i32) -> i32 {
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let length = length as i32;
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amplitude
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- ((2 * periods * (x + phase + length / (4 * periods)) * amplitude / length)
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% (2 * amplitude)
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- amplitude)
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.abs()
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- amplitude / 2
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}
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