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Audio I/O Fixes #17

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Merged
CorvusPrudens merged 2 commits into from
Mar 23, 2026
Merged

Audio I/O Fixes #17

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bf879b4
initial fix: blanket i/o channel swap for mismatch in expected SAI/I2…
stephenhensley Mar 23, 2026
78c83f1
secondary fix: resolves secondary channel-swap, and audio input buzz …
stephenhensley Mar 23, 2026
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55 changes: 25 additions & 30 deletions src/audio.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -23,7 +23,7 @@
stm32,
stm32::rcc::d2ccip1r::SAI1SEL_A,
time::Hertz,
traits::i2s::FullDuplex,

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unused import: `traits::i2s::FullDuplex`
};

// Process samples at 1000 Hz
Expand Down Expand Up @@ -182,6 +182,8 @@
.memory_increment(true)
.peripheral_increment(false)
.circular_buffer(true)
.transfer_complete_interrupt(true)
.half_transfer_interrupt(true)
.fifo_enable(false);
let mut output_stream = dma::Transfer::init(
dma1_stream0,
Expand All @@ -206,11 +208,10 @@

info!("Set up SAI...");
let sai1_rec = sai1_p.kernel_clk_mux(SAI1SEL_A::Pll3P);
let master_config =
I2SChanConfig::new(I2SDir::Rx).set_frame_sync_active_high(false);
let master_config = I2SChanConfig::new(I2SDir::Rx).set_frame_sync_active_high(true);
let slave_config = I2SChanConfig::new(I2SDir::Tx)
.set_sync_type(I2SSync::Internal)
.set_frame_sync_active_high(false);
.set_frame_sync_active_high(true);

let pins_a = (
sai_mclk_a.into_alternate(),
Expand Down Expand Up @@ -258,16 +259,9 @@
input_stream.start(|_sai1_rb| {
sai.enable_dma(SaiChannel::ChannelA);
});

output_stream.start(|sai1_rb| {
sai.enable();
output_stream.start(|_sai1_rb| {
sai.enable_dma(SaiChannel::ChannelB);

// wait until sai1's fifo starts to receive data
info!("Sai1 fifo waiting to receive data.");
while sai1_rb.chb().sr.read().flvl().is_empty() {}
info!("Audio started!");
sai.enable();
sai.try_send(0, 0).unwrap();
});

let max_transfer_size = block_size * 2;
Expand Down Expand Up @@ -334,11 +328,10 @@

info!("Setup up SAI...");
let sai1_rec = sai1_p.kernel_clk_mux(SAI1SEL_A::Pll3P);
let master_config =
I2SChanConfig::new(I2SDir::Tx).set_frame_sync_active_high(false);
let master_config = I2SChanConfig::new(I2SDir::Tx).set_frame_sync_active_high(true);
let slave_config = I2SChanConfig::new(I2SDir::Rx)
.set_sync_type(I2SSync::Internal)
.set_frame_sync_active_high(false);
.set_frame_sync_active_high(true);

let pins_a = (
sai_mclk_a.into_alternate(),
Expand Down Expand Up @@ -453,6 +446,8 @@
.memory_increment(true)
.peripheral_increment(false)
.circular_buffer(true)
.transfer_complete_interrupt(true)
.half_transfer_interrupt(true)
.fifo_enable(false);

let mut output_stream = dma::Transfer::init(
Expand Down Expand Up @@ -480,10 +475,10 @@
info!("Set up SAI...");
let sai1_rec = sai1_p.kernel_clk_mux(SAI1SEL_A::Pll3P);
let master_config =
sai::I2SChanConfig::new(sai::I2SDir::Rx).set_frame_sync_active_high(false);
sai::I2SChanConfig::new(sai::I2SDir::Rx).set_frame_sync_active_high(true);
let slave_config = sai::I2SChanConfig::new(sai::I2SDir::Tx)
.set_sync_type(sai::I2SSync::Internal)
.set_frame_sync_active_high(false);
.set_frame_sync_active_high(true);

let pins_a = (
sai_mclk_a.into_alternate(),
Expand Down Expand Up @@ -569,12 +564,12 @@
}

info!("Start audio stream...");
input_stream.start(|_sai1_rb| sai.enable_dma(sai::SaiChannel::ChannelA));
output_stream.start(|sai1_rb| {
sai.enable_dma(sai::SaiChannel::ChannelB);
while sai1_rb.chb().sr.read().flvl().is_empty() {}
sai.enable();
sai.try_send(0, 0).unwrap();
input_stream.start(|_sai1_rb| {
sai.enable_dma(SaiChannel::ChannelA);
});
sai.enable();
output_stream.start(|_sai1_rb| {
sai.enable_dma(SaiChannel::ChannelB);
});

let max_transfer_size = block_size * 2;
Expand Down Expand Up @@ -604,15 +599,15 @@
// Check interrupt(s)
match &mut self.audio_stream {
AudioStream::Normal { input, output } => {
output.clear_interrupts();
input.clear_interrupts();

if input.get_half_transfer_flag() {
input.clear_half_transfer_interrupt();
if output.get_half_transfer_flag() {
output.clear_half_transfer_interrupt();
self.input.set_index(0);
self.output.set_index(0);
true
} else if input.get_transfer_complete_flag() {
input.clear_transfer_complete_interrupt();
} else if output.get_transfer_complete_flag() {
output.clear_transfer_complete_interrupt();
self.input.set_index(self.max_transfer_size);
self.output.set_index(self.max_transfer_size);
true
Expand Down Expand Up @@ -645,8 +640,8 @@
// Check interrupt(s)
match &mut self.audio_stream {
AudioStream::Normal { input, output } => {
output.clear_interrupts();
input.get_half_transfer_flag() || input.get_transfer_complete_flag()
input.clear_interrupts();
output.get_half_transfer_flag() || output.get_transfer_complete_flag()
}
AudioStream::S2dfm { output, input } => {
input.clear_interrupts();
Expand All @@ -671,7 +666,7 @@
}
}

fn get_stereo_iter(&mut self) -> Option<StereoIterator> {

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hiding a lifetime that's elided elsewhere is confusing
if self.read() {
return Some(StereoIterator::new(
&self.input.buffer[self.input.index..self.input.index + self.max_transfer_size],
Expand Down Expand Up @@ -803,7 +798,7 @@
}

/// Get StereoIterator(interleaved) iterator
pub fn get_stereo_iter(&self) -> Option<StereoIterator> {

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hiding a lifetime that's elided elsewhere is confusing
Some(StereoIterator::new(&self.buffer[..2]))
}
}
Expand Down
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