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Add support for 8 channel I2S mono audio output on RPi 5 (#657)
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* First implementation of using four PCM5102 I2S sound devices for 8-channel mono sound output on a Raspberry Pi 5.  Requires latest develop branch of circle.

* Update to required develop branch of circle

* Adjusted default chunk sizes to correctly support number of channels.

* Update queue size as per Rene's suggestion.

---------

Co-authored-by: probonopd <[email protected]>
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@diyelectromusic @probonopd
diyelectromusic and probonopd authored Jun 29, 2024
1 parent afa72d2 commit 98b5274
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Showing 5 changed files with 167 additions and 78 deletions.
18 changes: 15 additions & 3 deletions src/config.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -41,15 +41,22 @@ void CConfig::Load (void)
m_SoundDevice = m_Properties.GetString ("SoundDevice", "pwm");

m_nSampleRate = m_Properties.GetNumber ("SampleRate", 48000);
m_bQuadDAC8Chan = m_Properties.GetNumber ("QuadDAC8Chan", 0) != 0;
if (m_SoundDevice == "hdmi") {
m_nChunkSize = m_Properties.GetNumber ("ChunkSize", 384*6);
}
else
{
#ifdef ARM_ALLOW_MULTI_CORE
m_nChunkSize = m_Properties.GetNumber ("ChunkSize", m_SoundDevice == "hdmi" ? 384*6 : 256);
m_nChunkSize = m_Properties.GetNumber ("ChunkSize", m_bQuadDAC8Chan ? 1024 : 256); // 128 per channel
#else
m_nChunkSize = m_Properties.GetNumber ("ChunkSize", m_SoundDevice == "hdmi" ? 384*6 : 1024);
m_nChunkSize = m_Properties.GetNumber ("ChunkSize", 1024);
#endif
}
m_nDACI2CAddress = m_Properties.GetNumber ("DACI2CAddress", 0);
m_bChannelsSwapped = m_Properties.GetNumber ("ChannelsSwapped", 0) != 0;

unsigned newEngineType = m_Properties.GetNumber ("EngineType", 1);
unsigned newEngineType = m_Properties.GetNumber ("EngineType", 1);
if (newEngineType == 2) {
m_EngineType = MKI;
} else if (newEngineType == 3) {
Expand Down Expand Up @@ -243,6 +250,11 @@ bool CConfig::GetExpandPCAcrossBanks (void) const
return m_bExpandPCAcrossBanks;
}

bool CConfig::GetQuadDAC8Chan (void) const
{
return m_bQuadDAC8Chan;
}

bool CConfig::GetLCDEnabled (void) const
{
return m_bLCDEnabled;
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2 changes: 2 additions & 0 deletions src/config.h
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Original file line number Diff line number Diff line change
Expand Up @@ -87,6 +87,7 @@ class CConfig // Configuration for MiniDexed
bool GetMIDIAutoVoiceDumpOnPC (void) const; // false if not specified
bool GetHeaderlessSysExVoices (void) const; // false if not specified
bool GetExpandPCAcrossBanks (void) const; // true if not specified
bool GetQuadDAC8Chan (void) const; // false if not specified

// HD44780 LCD
// GPIO pin numbers are chip numbers, not header positions
Expand Down Expand Up @@ -208,6 +209,7 @@ class CConfig // Configuration for MiniDexed
bool m_bMIDIAutoVoiceDumpOnPC;
bool m_bHeaderlessSysExVoices;
bool m_bExpandPCAcrossBanks;
bool m_bQuadDAC8Chan;

bool m_bLCDEnabled;
unsigned m_nLCDPinEnable;
Expand Down
222 changes: 148 additions & 74 deletions src/minidexed.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -42,6 +42,7 @@ CMiniDexed::CMiniDexed (CConfig *pConfig, CInterruptSystem *pInterrupt,
m_PCKeyboard (this, pConfig, &m_UI),
m_SerialMIDI (this, pInterrupt, pConfig, &m_UI),
m_bUseSerial (false),
m_bQuadDAC8Chan (false),
m_pSoundDevice (0),
m_bChannelsSwapped (pConfig->GetChannelsSwapped ()),
#ifdef ARM_ALLOW_MULTI_CORE
Expand Down Expand Up @@ -125,10 +126,26 @@ CMiniDexed::CMiniDexed (CConfig *pConfig, CInterruptSystem *pInterrupt,
if (strcmp (pDeviceName, "i2s") == 0)
{
LOGNOTE ("I2S mode");

m_pSoundDevice = new CI2SSoundBaseDevice (pInterrupt, pConfig->GetSampleRate (),
pConfig->GetChunkSize (), false,
pI2CMaster, pConfig->GetDACI2CAddress ());
#if RASPPI==5
// Quad DAC 8-channel mono only an option for RPI 5
m_bQuadDAC8Chan = pConfig->GetQuadDAC8Chan ();
#endif
if (m_bQuadDAC8Chan) {
LOGNOTE ("Configured for Quad DAC 8-channel Mono audio");
m_pSoundDevice = new CI2SSoundBaseDevice (pInterrupt, pConfig->GetSampleRate (),
pConfig->GetChunkSize (), false,
pI2CMaster, pConfig->GetDACI2CAddress (),
CI2SSoundBaseDevice::DeviceModeTXOnly,
8); // 8 channels - L+R x4 across 4 I2S lanes
}
else
{
m_pSoundDevice = new CI2SSoundBaseDevice (pInterrupt, pConfig->GetSampleRate (),
pConfig->GetChunkSize (), false,
pI2CMaster, pConfig->GetDACI2CAddress (),
CI2SSoundBaseDevice::DeviceModeTXOnly,
2); // 2 channels - L+R
}
}
else if (strcmp (pDeviceName, "hdmi") == 0)
{
Expand Down Expand Up @@ -251,18 +268,30 @@ bool CMiniDexed::Initialize (void)
}

// setup and start the sound device
if (!m_pSoundDevice->AllocateQueueFrames (m_pConfig->GetChunkSize ()))
int Channels = 1; // 16-bit Mono
#ifdef ARM_ALLOW_MULTI_CORE
if (m_bQuadDAC8Chan)
{
Channels = 8; // 16-bit 8-channel mono
}
else
{
Channels = 2; // 16-bit Stereo
}
#endif
// Need 2 x ChunkSize / Channel queue frames as the audio driver uses
// two DMA channels each of ChunkSize and one single single frame
// contains a sample for each of all the channels.
//
// See discussion here: https://github.com/rsta2/circle/discussions/453
if (!m_pSoundDevice->AllocateQueueFrames (2 * m_pConfig->GetChunkSize () / Channels))
{
LOGERR ("Cannot allocate sound queue");

return false;
}

#ifndef ARM_ALLOW_MULTI_CORE
m_pSoundDevice->SetWriteFormat (SoundFormatSigned16, 1); // 16-bit Mono
#else
m_pSoundDevice->SetWriteFormat (SoundFormatSigned16, 2); // 16-bit Stereo
#endif
m_pSoundDevice->SetWriteFormat (SoundFormatSigned16, Channels);

m_nQueueSizeFrames = m_pSoundDevice->GetQueueSizeFrames ();

Expand Down Expand Up @@ -1128,85 +1157,130 @@ void CMiniDexed::ProcessSound (void)

assert (CConfig::ToneGenerators == 8);

uint8_t indexL=0, indexR=1;

// BEGIN TG mixing
float32_t tmp_float[nFrames*2];
int16_t tmp_int[nFrames*2];
if (m_bQuadDAC8Chan) {
// No mixing is performed by MiniDexed, sound is output in 8 channels.
// Note: one TG per audio channel; output=mono; no processing.
const int Channels = 8; // One TG per channel
float32_t tmp_float[nFrames*Channels];
int16_t tmp_int[nFrames*Channels];

if(nMasterVolume > 0.0)
{
for (uint8_t i = 0; i < CConfig::ToneGenerators; i++)
if(nMasterVolume > 0.0)
{
tg_mixer->doAddMix(i,m_OutputLevel[i]);
reverb_send_mixer->doAddMix(i,m_OutputLevel[i]);
// Convert dual float array (8 chan) to single int16 array (8 chan)
for(uint16_t i=0; i<nFrames;i++)
{
// TGs will alternate on L/R channels for each output
// reading directly from the TG OutputLevel buffer with
// no additional processing.
for (uint8_t tg = 0; tg < Channels; tg++)
{
if(nMasterVolume >0.0 && nMasterVolume <1.0)
{
tmp_float[(i*Channels)+tg]=m_OutputLevel[tg][i] * nMasterVolume;
}
else if(nMasterVolume == 1.0)
{
tmp_float[(i*Channels)+tg]=m_OutputLevel[tg][i];
}
}
}
arm_float_to_q15(tmp_float,tmp_int,nFrames*Channels);
}
// END TG mixing

// BEGIN create SampleBuffer for holding audio data
float32_t SampleBuffer[2][nFrames];
// END create SampleBuffer for holding audio data

// get the mix of all TGs
tg_mixer->getMix(SampleBuffer[indexL], SampleBuffer[indexR]);

// BEGIN adding reverb
if (m_nParameter[ParameterReverbEnable])
else
{
float32_t ReverbBuffer[2][nFrames];
float32_t ReverbSendBuffer[2][nFrames];

arm_fill_f32(0.0f, ReverbBuffer[indexL], nFrames);
arm_fill_f32(0.0f, ReverbBuffer[indexR], nFrames);
arm_fill_f32(0.0f, ReverbSendBuffer[indexR], nFrames);
arm_fill_f32(0.0f, ReverbSendBuffer[indexL], nFrames);

m_ReverbSpinLock.Acquire ();

reverb_send_mixer->getMix(ReverbSendBuffer[indexL], ReverbSendBuffer[indexR]);
reverb->doReverb(ReverbSendBuffer[indexL],ReverbSendBuffer[indexR],ReverbBuffer[indexL], ReverbBuffer[indexR],nFrames);

// scale down and add left reverb buffer by reverb level
arm_scale_f32(ReverbBuffer[indexL], reverb->get_level(), ReverbBuffer[indexL], nFrames);
arm_add_f32(SampleBuffer[indexL], ReverbBuffer[indexL], SampleBuffer[indexL], nFrames);
// scale down and add right reverb buffer by reverb level
arm_scale_f32(ReverbBuffer[indexR], reverb->get_level(), ReverbBuffer[indexR], nFrames);
arm_add_f32(SampleBuffer[indexR], ReverbBuffer[indexR], SampleBuffer[indexR], nFrames);

m_ReverbSpinLock.Release ();
arm_fill_q15(0, tmp_int, nFrames*Channels);
}
// END adding reverb

// swap stereo channels if needed prior to writing back out
if (m_bChannelsSwapped)

if (m_pSoundDevice->Write (tmp_int, sizeof(tmp_int)) != (int) sizeof(tmp_int))
{
indexL=1;
indexR=0;
LOGERR ("Sound data dropped");
}
}
else
{
// Mix everything down to stereo
uint8_t indexL=0, indexR=1;

// BEGIN TG mixing
float32_t tmp_float[nFrames*2];
int16_t tmp_int[nFrames*2];

// Convert dual float array (left, right) to single int16 array (left/right)
for(uint16_t i=0; i<nFrames;i++)
if(nMasterVolume > 0.0)
{
if(nMasterVolume >0.0 && nMasterVolume <1.0)
for (uint8_t i = 0; i < CConfig::ToneGenerators; i++)
{
tmp_float[i*2]=SampleBuffer[indexL][i] * nMasterVolume;
tmp_float[(i*2)+1]=SampleBuffer[indexR][i] * nMasterVolume;
tg_mixer->doAddMix(i,m_OutputLevel[i]);
reverb_send_mixer->doAddMix(i,m_OutputLevel[i]);
}
else if(nMasterVolume == 1.0)
// END TG mixing

// BEGIN create SampleBuffer for holding audio data
float32_t SampleBuffer[2][nFrames];
// END create SampleBuffer for holding audio data

// get the mix of all TGs
tg_mixer->getMix(SampleBuffer[indexL], SampleBuffer[indexR]);

// BEGIN adding reverb
if (m_nParameter[ParameterReverbEnable])
{
tmp_float[i*2]=SampleBuffer[indexL][i];
tmp_float[(i*2)+1]=SampleBuffer[indexR][i];
float32_t ReverbBuffer[2][nFrames];
float32_t ReverbSendBuffer[2][nFrames];

arm_fill_f32(0.0f, ReverbBuffer[indexL], nFrames);
arm_fill_f32(0.0f, ReverbBuffer[indexR], nFrames);
arm_fill_f32(0.0f, ReverbSendBuffer[indexR], nFrames);
arm_fill_f32(0.0f, ReverbSendBuffer[indexL], nFrames);

m_ReverbSpinLock.Acquire ();

reverb_send_mixer->getMix(ReverbSendBuffer[indexL], ReverbSendBuffer[indexR]);
reverb->doReverb(ReverbSendBuffer[indexL],ReverbSendBuffer[indexR],ReverbBuffer[indexL], ReverbBuffer[indexR],nFrames);

// scale down and add left reverb buffer by reverb level
arm_scale_f32(ReverbBuffer[indexL], reverb->get_level(), ReverbBuffer[indexL], nFrames);
arm_add_f32(SampleBuffer[indexL], ReverbBuffer[indexL], SampleBuffer[indexL], nFrames);
// scale down and add right reverb buffer by reverb level
arm_scale_f32(ReverbBuffer[indexR], reverb->get_level(), ReverbBuffer[indexR], nFrames);
arm_add_f32(SampleBuffer[indexR], ReverbBuffer[indexR], SampleBuffer[indexR], nFrames);

m_ReverbSpinLock.Release ();
}
// END adding reverb

// swap stereo channels if needed prior to writing back out
if (m_bChannelsSwapped)
{
indexL=1;
indexR=0;
}

// Convert dual float array (left, right) to single int16 array (left/right)
for(uint16_t i=0; i<nFrames;i++)
{
if(nMasterVolume >0.0 && nMasterVolume <1.0)
{
tmp_float[i*2]=SampleBuffer[indexL][i] * nMasterVolume;
tmp_float[(i*2)+1]=SampleBuffer[indexR][i] * nMasterVolume;
}
else if(nMasterVolume == 1.0)
{
tmp_float[i*2]=SampleBuffer[indexL][i];
tmp_float[(i*2)+1]=SampleBuffer[indexR][i];
}
}
arm_float_to_q15(tmp_float,tmp_int,nFrames*2);
}
else
{
arm_fill_q15(0, tmp_int, nFrames * 2);
}
arm_float_to_q15(tmp_float,tmp_int,nFrames*2);
}
else
arm_fill_q15(0, tmp_int, nFrames * 2);

if (m_pSoundDevice->Write (tmp_int, sizeof(tmp_int)) != (int) sizeof(tmp_int))
{
LOGERR ("Sound data dropped");
}
if (m_pSoundDevice->Write (tmp_int, sizeof(tmp_int)) != (int) sizeof(tmp_int))
{
LOGERR ("Sound data dropped");
}
} // End of Stereo mixing

if (m_bProfileEnabled)
{
Expand Down
1 change: 1 addition & 0 deletions src/minidexed.h
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Original file line number Diff line number Diff line change
Expand Up @@ -298,6 +298,7 @@ class CMiniDexed
CPCKeyboard m_PCKeyboard;
CSerialMIDIDevice m_SerialMIDI;
bool m_bUseSerial;
bool m_bQuadDAC8Chan;

CSoundBaseDevice *m_pSoundDevice;
bool m_bChannelsSwapped;
Expand Down
2 changes: 1 addition & 1 deletion submod.sh
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Original file line number Diff line number Diff line change
Expand Up @@ -12,7 +12,7 @@ cd -
#
# Optional update submodules explicitly
cd circle-stdlib/libs/circle
git checkout 4155f43
git checkout fff3764
cd -
cd circle-stdlib/libs/circle-newlib
#git checkout develop
Expand Down

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