aiie/teensy/teensy-speaker.cpp

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#include <Arduino.h>
#include "teensy-speaker.h"
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#include "teensy-println.h"
#include <Audio.h>
TeensyAudio audioDriver;
AudioMixer4 mixer2; //xy=280,253
AudioMixer4 mixer1; //xy=280,175
//AudioOutputI2S i2s; //xy=452,189
AudioOutputMQS i2s; //xy=452,189
AudioConnection patchCord1(audioDriver, 0, mixer1, 0);
AudioConnection patchCord2(audioDriver, 0, mixer2, 0);
AudioConnection patchCord3(mixer2, 0, i2s, 1);
AudioConnection patchCord4(mixer1, 0, i2s, 0);
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#include "globals.h"
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#define HIGHVAL (0x4FFF)
#define LOWVAL (-0x4FFF)
// Ring buffer that we fill with 44.1kHz data
#define BUFSIZE (4096)
#define CACHEMULTIPLIER 10
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static volatile uint32_t bufIdx; // 0 .. BUFSIZE-1
static volatile uint64_t skippedSamples; // Who knows where this will
// wind up
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static volatile uint8_t audioRunning = 0; // FIXME: needs constants abstracted
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static volatile int64_t lastFilledTime = 0;
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// how full do we want the audio buffer before we start it playing?
#define AUDIO_WATERLEVEL 4096
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#define SAMPLEBYTES sizeof(short)
EXTMEM short soundBuf[BUFSIZE*CACHEMULTIPLIER];
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static bool toggleState = false;
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TeensySpeaker::TeensySpeaker(uint8_t sda, uint8_t scl) : PhysicalSpeaker()
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{
toggleState = false;
mixerValue = 0x80;
AudioMemory(8);
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}
TeensySpeaker::~TeensySpeaker()
{
}
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void TeensySpeaker::begin()
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{
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float curVolume = (float)g_volume / 15.0;
mixer1.gain(0, curVolume); // left channel
mixer1.gain(1, curVolume); // right channel
mixer2.gain(0, curVolume); // left channel
mixer2.gain(1, curVolume); // right channel
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memset(soundBuf, 0, sizeof(soundBuf));
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toggleState = false;
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bufIdx = 0;
skippedSamples = 0;
audioRunning = 0;
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}
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void TeensySpeaker::toggle(int64_t c)
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{
// Figure out when the last time was that we put data in the audio buffer;
// then figure out how many audio buffer cycles we have to fill from that
// CPU time to this one.
__disable_irq();
// We expect to have filled to this cycle number...
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int64_t expectedCycleNumber = (float)c * (float)AUDIO_SAMPLE_RATE_EXACT / (float)g_speed;
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// Dynamically initialize the lastFilledTime based on the start time of the
// audio channel.
if (lastFilledTime == 0)
lastFilledTime = expectedCycleNumber;
// and we have filled to cycle number lastFilledTime. So how many do
// we need? This subtracts skippedSamples because those were filled
// automatically by the audioCallback when we had no data.
int64_t audioBufferSamples = expectedCycleNumber - lastFilledTime - skippedSamples;
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// If audioBufferSamples < 0, then we need to keep some
// skippedSamples for later; otherwise we can keep moving forward.
if (audioBufferSamples < 0) {
skippedSamples = -audioBufferSamples;
audioBufferSamples = 0;
} else {
// Otherwise we consumed them and can forget about it.
skippedSamples = 0;
}
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int32_t newIdx = bufIdx + audioBufferSamples;
if (audioBufferSamples == 0) {
// If the toggle wouldn't result in at least 1 buffer sample
// change, then we'll blatantly skip it here. If this turns out to
// be a problem, we could try setting audioBufferSamples++ and
// then twiddle the lastFilledTime so it looks like it's more in
// the future, but I suspect that would mean missing more future
// events, just like we would have missed this one.
//
// But I think this is probably okay - because something that's
// toggling the speaker fast enough that our 44k audio can't keep
// up with the individual changes is likely to toggle again in a
// moment without significant distortion?
__enable_irq();
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return;
}
if (newIdx >= sizeof(soundBuf)/SAMPLEBYTES) {
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// Buffer overrun error. Shouldn't happen?
println("OVERRUN");
newIdx = (sizeof(soundBuf)/SAMPLEBYTES) - 1;
}
lastFilledTime = expectedCycleNumber;
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// Flip the toggle state
toggleState = !toggleState;
// Fill from bufIdx .. newIdx and set bufIdx to newIdx when done.
if (newIdx > bufIdx) {
long count = (long)newIdx - bufIdx;
for (long i=0; i<count; i++) {
if (bufIdx+i+1 < sizeof(soundBuf)/sizeof(short)) {
soundBuf[bufIdx+i] = toggleState ? HIGHVAL : LOWVAL;
}
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}
bufIdx = newIdx;
}
__enable_irq();
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}
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void TeensySpeaker::maintainSpeaker(int64_t c, uint64_t microseconds)
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{
begin(); // flush! Hack. FIXME.
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}
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void TeensySpeaker::maintainSpeaker()
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{
}
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void TeensySpeaker::beginMixing()
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{
// unused
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}
void TeensySpeaker::mixOutput(uint8_t v)
{
// unused
}
void TeensyAudio::update(void)
{
audio_block_t *block;
short *stream;
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if (audioRunning == 0)
audioRunning = 1;
block = allocate();
if (!block) {
return;
}
stream = block->data;
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if (g_biosInterrupt) {
// While the BIOS is running, we don't put samples in the audio queue.
audioRunning = 0;
memset(stream, 0, AUDIO_BLOCK_SAMPLES * SAMPLEBYTES);
goto done;
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}
if (audioRunning == 1 && bufIdx >= AUDIO_WATERLEVEL) {
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// We have enough samples in the buffer to fill it, so we're fully
// up and running.
audioRunning = 2;
} else if (audioRunning == 1) {
// Still waiting for the first fill; return an empty buffer.
memset(stream, 0, AUDIO_BLOCK_SAMPLES * SAMPLEBYTES);
goto done;
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}
static short lastKnownSample = 0; // saved for when the apple is quiescent
if (bufIdx >= AUDIO_BLOCK_SAMPLES) {
memcpy(stream, (void *)soundBuf, AUDIO_BLOCK_SAMPLES * SAMPLEBYTES);
lastKnownSample = stream[AUDIO_BLOCK_SAMPLES-1];
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if (bufIdx > AUDIO_BLOCK_SAMPLES) {
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// move the remaining data down
memcpy((void *)soundBuf, (void *)&soundBuf[AUDIO_BLOCK_SAMPLES], (bufIdx - AUDIO_BLOCK_SAMPLES + 1)*SAMPLEBYTES);
bufIdx -= AUDIO_BLOCK_SAMPLES;
}
} else {
if (bufIdx) {
// partial buffer exists
memcpy(stream, (void *)soundBuf, bufIdx * SAMPLEBYTES);
// and it's a partial underrun. Track the number of samples we skipped
// so we can keep the audio buffer in sync.
skippedSamples += AUDIO_BLOCK_SAMPLES - bufIdx;
for (int32_t i=0; i<AUDIO_BLOCK_SAMPLES-bufIdx; i++) {
stream[i+bufIdx] = lastKnownSample;
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}
bufIdx = 0;
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} else {
// No big deal - buffer underrun might just mean nothing is
// trying to play audio right now.
skippedSamples += AUDIO_BLOCK_SAMPLES;
for (int32_t i=0; i<AUDIO_BLOCK_SAMPLES; i++) {
stream[i] = 0;
}
// memset(stream, 0, AUDIO_BLOCK_SAMPLES * SAMPLEBYTES);
}
}
done:
transmit(block, 0);
release(block);
}