313 lines
9.7 KiB
C++
313 lines
9.7 KiB
C++
#pragma once
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// https://github.com/Jean-MarcHarvengt/VGA_t4
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// https://forum.pjrc.com/threads/63243-Writing-Directly-to-SGTL5000-CODEC-DACs
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// https://community.nxp.com/t5/Kinetis-Microcontrollers/is-there-any-demo-code-for-using-I2S/m-p/196195/highlight/true
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// https://github.com/PaulStoffregen/Audio/blob/99b9472afd24bea13efc799742c0ea432ef2303a/output_i2s.cpp
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#include "../../Debug.h"
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#define I2S2_USE_DMA
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#ifdef I2S2_USE_DMA
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#include <DMAChannel.h>
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#endif
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// the buffer has a size of X samples,
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// and we receive an interrupt whenever ONE HALF was transmitted
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// 1152 = MP3 decode size, *2 (stereo), *2 (2 buffer halfs)
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static constexpr const uint32_t I2S2_BUFFER_SAMPLES = 1152*2*2;
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#include "I2SBase.h"
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class I2S2 {
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private:
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static constexpr const char* NAME = "I2S2";
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/** the actual PCM data buffer */
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static DMAMEM __attribute__((aligned(32))) int16_t buffer[I2S2_BUFFER_SAMPLES];
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/** helper class to map one half of above buffer */
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struct BufferHalf {
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int16_t* mem;
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volatile uint16_t samplesUsed = 0;
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uint16_t samplesFree() const {return I2S2_BUFFER_SAMPLES/2 - samplesUsed;}
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BufferHalf(int16_t* mem) : mem(mem) {}
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bool isFilled() const {return samplesFree() == 0;}
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void dropCache() {arm_dcache_flush_delete(mem, I2S2_BUFFER_SAMPLES/2*sizeof(int16_t));}
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};
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struct State {
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#ifdef I2S2_USE_DMA
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DMAChannel dma;
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volatile uint8_t transmittingHalf = 0;
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BufferHalf bufferHalf[2] = {
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BufferHalf(&buffer[0]),
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BufferHalf(&buffer[I2S2_BUFFER_SAMPLES/2]),
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};
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/** the current half was transmitted, switch to the next one */
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void halfTransmitted() {
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bufferHalf[transmittingHalf].samplesUsed = 0;
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//memset(bufferHalf[transmittingHalf].mem, 0, I2S2_BUFFER_SAMPLES/2*sizeof(int16_t));
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transmittingHalf = (transmittingHalf + 1) % 2;
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bufferHalf[transmittingHalf].dropCache();
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}
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/** the BufferHalf we are currently filling when adding new data */
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BufferHalf& fillingHalf() {
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return bufferHalf[(transmittingHalf+1)%2];
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}
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#else
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// TODO
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#endif
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};
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static State state;
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public:
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/** start the i2s transmission with the given values */
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static void setup(uint8_t channels, uint32_t sampleRate_hz) {
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Log::addInfo(NAME, "start(%d, %d)", channels, sampleRate_hz);
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// zero out the audio data buffer
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clearBuffer();
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// configure the I2S unit
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config_sai2(sampleRate_hz);
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#ifdef I2S2_USE_DMA
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state.dma.begin(true); // Allocate the DMA channel first
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state.dma.TCD->SADDR = buffer; // source address
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state.dma.TCD->SOFF = 2; // source buffer address increment per transfer in bytes
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state.dma.TCD->ATTR = DMA_TCD_ATTR_SSIZE(1) | DMA_TCD_ATTR_DSIZE(1); // specifies 16 bit source and destination
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state.dma.TCD->NBYTES_MLNO = 2; // bytes to transfer for each service request///////////////////////////////////////////////////////////////////
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state.dma.TCD->SLAST = -sizeof(buffer); // last source address adjustment
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state.dma.TCD->DOFF = 0; // increments at destination
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state.dma.TCD->CITER_ELINKNO = sizeof(buffer) / 2;
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state.dma.TCD->DLASTSGA = 0; // destination address offset
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state.dma.TCD->BITER_ELINKNO = sizeof(buffer) / 2;
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state.dma.TCD->CSR = DMA_TCD_CSR_INTHALF | DMA_TCD_CSR_INTMAJOR; // enables interrupt when transfers half complete. SET TO 0 to disable DMA interrupts
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state.dma.TCD->DADDR = (void *)((uint32_t)&I2S2_TDR0 + 2); // I2S2 register DMA writes to
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state.dma.triggerAtHardwareEvent(DMAMUX_SOURCE_SAI2_TX); // i2s channel that will trigger the DMA transfer when ready for data
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state.dma.enable();
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state.dma.attachInterrupt(I2S2::isrDMA);
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Log::addInfo(NAME, "DMA configured");
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#else
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attachInterruptVector(IRQ_SAI2, isrAudio);
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NVIC_ENABLE_IRQ(IRQ_SAI2);
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NVIC_SET_PRIORITY(IRQ_SAI2, 127);
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I2S2_TCSR |= 1<<8; // start generating TX FIFO interrupts
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#endif
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}
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/** zero-out the audio buffer */
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static void clearBuffer() {
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memset(buffer, 0, sizeof(buffer));
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state.bufferHalf[0].samplesUsed = 0;
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state.bufferHalf[1].samplesUsed = 0;
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}
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/** block until the given number of samples were added to the internal buffer */
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static void addBlocking(const int16_t* pcm, uint16_t numSamples) {
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while(numSamples) {
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const uint32_t samplesAdded = addNonBlocking(pcm, numSamples);
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numSamples -= samplesAdded;
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pcm += samplesAdded;
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}
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}
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/** add the given number of samples to the internal buffer, returns the number of actually added samples, dependent on how much space there was */
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static uint16_t addNonBlocking(const int16_t* pcm, uint16_t numSamples) {
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#ifdef I2S2_USE_DMA
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BufferHalf& bh = state.fillingHalf();
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const uint16_t addable = min(numSamples, bh.samplesFree());
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uint8_t* dst = (uint8_t*) (&bh.mem[bh.samplesUsed]);
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uint16_t numBytes = addable * sizeof(int16_t);
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memcpy(dst, pcm, numBytes);
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bh.samplesUsed += addable;
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return addable;
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#else
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// TODO, NOT YET IMPLEMENTED
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if (freeEntries < SAMPLES_PER_BUFFER) {return false;}
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//int16_t* dst = &audioBuffer[bufHead];
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//memcpy(dst, samples, SAMPLES_PER_BUFFER*sizeof(int16_t));
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//bufHead = (bufHead + SAMPLES_PER_BUFFER) % NUM_ENTRIES;
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//curBuffer = (curBuffer + 1) % NUM_BUFFERS;
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for (uint16_t i = 0; i < SAMPLES_PER_BUFFER; ++i) {
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audioBuffer[bufHead] = samples[i];
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bufHead = (bufHead + 1) % NUM_ENTRIES;
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}
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freeEntries -= SAMPLES_PER_BUFFER;
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arm_dcache_flush_delete(audioBuffer, NUM_ENTRIES*sizeof(int16_t));
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return true;
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#endif
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}
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private:
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#ifdef I2S2_USE_DMA
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FASTRUN static void isrDMA() {
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// one buffer half processed -> next
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state.dma.clearInterrupt();
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state.halfTransmitted();
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}
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#else
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// interrupt service routine
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static void isrAudio() {
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// TODO, not yet implemented
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static constexpr volatile uint16_t* txReg = (uint16_t *)((uint32_t)&I2S2_TDR0 + 2);
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//static constexpr uint16_t* txReg = (uint16_t *)((uint32_t)&I2S2_TDR0 );
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//if (CHANNELS == 2) {
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const uint16_t sample1 = audioBuffer[bufTail];
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//*txReg = sample1;
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bufTail = (bufTail + 1) & (NUM_ENTRIES-1);
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if (freeEntries < NUM_ENTRIES) {++freeEntries;}
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*txReg = sample1;
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//}
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}
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#endif
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private:
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static void config_sai2(uint32_t sampleRate_hz) {
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CCM_CCGR5 |= CCM_CCGR5_SAI2(CCM_CCGR_ON);
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double fs = sampleRate_hz;
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// PLL between 27*24 = 648MHz und 54*24=1296MHz
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int n1 = 4; //SAI prescaler 4 => (n1*n2) = multiple of 4
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int n2 = 1 + (24000000 * 27) / (fs * 256 * n1);
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double C = (fs * 256 * n1 * n2) / 24000000;
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int c0 = C;
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int c2 = 10000;
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int c1 = C * c2 - (c0 * c2);
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setAudioClock(c0, c1, c2, true);
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// clear SAI2_CLK register locations
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CCM_CSCMR1 = (CCM_CSCMR1 & ~(CCM_CSCMR1_SAI2_CLK_SEL_MASK))
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| CCM_CSCMR1_SAI2_CLK_SEL(2); // &0x03 // (0,1,2): PLL3PFD0, PLL5, PLL4
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//n1 = n1 / 2; //Double Speed for TDM
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CCM_CS2CDR = (CCM_CS2CDR & ~(CCM_CS2CDR_SAI2_CLK_PRED_MASK | CCM_CS2CDR_SAI2_CLK_PODF_MASK))
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| CCM_CS2CDR_SAI2_CLK_PRED(n1 - 1)
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| CCM_CS2CDR_SAI2_CLK_PODF(n2 - 1);
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// kazu: OK WITHOUT??
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IOMUXC_GPR_GPR1 = (IOMUXC_GPR_GPR1 & ~(IOMUXC_GPR_GPR1_SAI2_MCLK3_SEL_MASK)) | (IOMUXC_GPR_GPR1_SAI2_MCLK_DIR | IOMUXC_GPR_GPR1_SAI2_MCLK3_SEL(0)); //Select MCLK
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// configure transmitter
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const int rsync = 0;
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const int tsync = 1;
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uint16_t by = 32; // ??
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// configure transmitter
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I2S2_TMR = 0;
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I2S2_TCR1 = I2S_TCR1_RFW(1);
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I2S2_TCR2 = I2S_TCR2_SYNC(tsync) | I2S_TCR2_BCP | (I2S_TCR2_BCD | I2S_TCR2_DIV((1)) | I2S_TCR2_MSEL(1)); // sync=0; tx is async;
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I2S2_TCR3 = I2S_TCR3_TCE;
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I2S2_TCR4 = I2S_TCR4_FRSZ((2-1)) | I2S_TCR4_SYWD((by-1)) | I2S_TCR4_MF | I2S_TCR4_FSD | I2S_TCR4_FSE | I2S_TCR4_FSP;
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I2S2_TCR5 = I2S_TCR5_WNW((by-1)) | I2S_TCR5_W0W((by-1)) | I2S_TCR5_FBT((by-1)); // page 1995
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I2S2_RMR = 0;
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I2S2_RCR1 = I2S_RCR1_RFW(1);
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I2S2_RCR2 = I2S_RCR2_SYNC(rsync) | I2S_RCR2_BCP | (I2S_RCR2_BCD | I2S_RCR2_DIV((1)) | I2S_RCR2_MSEL(1)); // sync=0; rx is async;
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I2S2_RCR3 = I2S_RCR3_RCE;
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I2S2_RCR4 = I2S_RCR4_FRSZ((2-1)) | I2S_RCR4_SYWD((by-1)) | I2S_RCR4_MF | I2S_RCR4_FSE | I2S_RCR4_FSP | I2S_RCR4_FSD;
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I2S2_RCR5 = I2S_RCR5_WNW((by-1)) | I2S_RCR5_W0W((by-1)) | I2S_RCR5_FBT((by-1));
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// configure pins (2,3,4) to their I2S functionality
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CORE_PIN4_CONFIG = 2; // RX_BCLK
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CORE_PIN3_CONFIG = 2; // RX_SYNC (left/right)
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CORE_PIN2_CONFIG = 2; // TX_DATA0
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I2S2_RCSR |= I2S_RCSR_RE | I2S_RCSR_BCE;
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#ifdef I2S2_USE_DMA
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I2S2_TCSR = I2S_TCSR_TE | I2S_TCSR_BCE | I2S_TCSR_FRDE; // | I2S_TCSR_FR ???
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#else
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I2S2_TCSR = I2S_TCSR_TE | I2S_TCSR_BCE;
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#endif
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}
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FLASHMEM static void setAudioClock(int nfact, int32_t nmult, uint32_t ndiv, bool force) {// sets PLL4
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if (!force && (CCM_ANALOG_PLL_AUDIO & CCM_ANALOG_PLL_AUDIO_ENABLE)) return;
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CCM_ANALOG_PLL_AUDIO = CCM_ANALOG_PLL_AUDIO_BYPASS | CCM_ANALOG_PLL_AUDIO_ENABLE
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| CCM_ANALOG_PLL_AUDIO_POST_DIV_SELECT(2) // 2: 1/4; 1: 1/2; 0: 1/1
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| CCM_ANALOG_PLL_AUDIO_DIV_SELECT(nfact);
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CCM_ANALOG_PLL_AUDIO_NUM = nmult & CCM_ANALOG_PLL_AUDIO_NUM_MASK;
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CCM_ANALOG_PLL_AUDIO_DENOM = ndiv & CCM_ANALOG_PLL_AUDIO_DENOM_MASK;
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CCM_ANALOG_PLL_AUDIO &= ~CCM_ANALOG_PLL_AUDIO_POWERDOWN;//Switch on PLL
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while (!(CCM_ANALOG_PLL_AUDIO & CCM_ANALOG_PLL_AUDIO_LOCK)) {}; //Wait for pll-lock
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const int div_post_pll = 1; // other values: 2,4
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CCM_ANALOG_MISC2 &= ~(CCM_ANALOG_MISC2_DIV_MSB | CCM_ANALOG_MISC2_DIV_LSB);
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if(div_post_pll>1) CCM_ANALOG_MISC2 |= CCM_ANALOG_MISC2_DIV_LSB;
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if(div_post_pll>3) CCM_ANALOG_MISC2 |= CCM_ANALOG_MISC2_DIV_MSB;
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CCM_ANALOG_PLL_AUDIO &= ~CCM_ANALOG_PLL_AUDIO_BYPASS;//Disable Bypass
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}
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};
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// init static class members
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#ifdef I2S2_IMPLEMENTATION
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DMAMEM __attribute__((aligned(32))) int16_t I2S2::buffer[I2S2_BUFFER_SAMPLES];
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I2S2::State I2S2::state;
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#endif
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