84 lines
2.4 KiB
Rust
84 lines
2.4 KiB
Rust
// This example is written for an STM32F411 chip communicating with an external
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// PCM5102a DAC. Remap pins, change clock speeds, etc. as necessary for your own
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// hardware.
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//
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// NOTE: This example outputs potentially loud audio. Please run responsibly.
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#![no_std]
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#![no_main]
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use embassy_executor::Spawner;
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use embassy_stm32::i2s::{Config, Format, I2S};
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use embassy_stm32::time::Hertz;
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use {defmt_rtt as _, panic_probe as _};
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#[embassy_executor::main]
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async fn main(_spawner: Spawner) {
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let config = {
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use embassy_stm32::rcc::*;
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let mut config = embassy_stm32::Config::default();
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config.rcc.hse = Some(Hse {
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freq: Hertz::mhz(25),
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mode: HseMode::Oscillator,
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});
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config.rcc.pll_src = PllSource::HSE;
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config.rcc.pll = Some(Pll {
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prediv: PllPreDiv::DIV25,
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mul: PllMul::MUL192,
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divp: Some(PllPDiv::DIV2),
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divq: Some(PllQDiv::DIV4),
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divr: None,
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});
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config.rcc.sys = Sysclk::PLL1_P;
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config.rcc.ahb_pre = AHBPrescaler::DIV1;
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config.rcc.apb1_pre = APBPrescaler::DIV2;
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config.rcc.apb2_pre = APBPrescaler::DIV1;
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// reference your chip's manual for proper clock settings; this config
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// is recommended for a 32 bit frame at 48 kHz sample rate
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config.rcc.plli2s = Some(Pll {
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prediv: PllPreDiv::DIV25,
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mul: PllMul::MUL384,
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divp: None,
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divq: None,
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divr: Some(PllRDiv::DIV5),
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});
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config.enable_debug_during_sleep = true;
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config
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};
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let p = embassy_stm32::init(config);
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// stereo wavetable generation
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let mut wavetable = [0u16; 1200];
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for (i, frame) in wavetable.chunks_mut(2).enumerate() {
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frame[0] = ((((i / 150) % 2) * 2048) as i16 - 1024) as u16; // 160 Hz square wave in left channel
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frame[1] = ((((i / 100) % 2) * 2048) as i16 - 1024) as u16; // 240 Hz square wave in right channel
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}
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// i2s configuration
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let mut dma_buffer = [0u16; 2400];
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let mut i2s_config = Config::default();
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i2s_config.format = Format::Data16Channel32;
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i2s_config.master_clock = false;
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let mut i2s = I2S::new_txonly_nomck(
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p.SPI3,
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p.PB5, // sd
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p.PA15, // ws
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p.PB3, // ck
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p.DMA1_CH7,
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&mut dma_buffer,
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Hertz(48_000),
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i2s_config,
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);
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i2s.start();
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loop {
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i2s.write(&wavetable).await.ok();
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}
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}
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