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teensy-audio
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Add Teensy 4 PWM output 

Attention, only tested with my oscilloscopy, no audible test.

I'm a bit unsure about the different value(+120) for the MSB on Teensy. This may need a fix.
Also, T3 uses the 2.5xsamplerate - this is not implemented, too.
dds
Frank 4 years ago
parent
6decc27093
commit
b94f846231
No account linked to committer's email address
2 changed files with 230 additions and 6 deletions
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  1. +202
    -2
      output_pwm.cpp
  2. +28
    -4
      output_pwm.h

+ 202
- 2
output_pwm.cpp View File

@@ -27,10 +27,12 @@
#include <Arduino.h>
#include "output_pwm.h"

bool AudioOutputPWM::update_responsibility = false;

#if defined(KINETISK)
audio_block_t * AudioOutputPWM::block_1st = NULL;
audio_block_t * AudioOutputPWM::block_2nd = NULL;
uint32_t AudioOutputPWM::block_offset = 0;
bool AudioOutputPWM::update_responsibility = false;
uint8_t AudioOutputPWM::interrupt_count = 0;

DMAMEM uint32_t pwm_dma_buffer[AUDIO_BLOCK_SAMPLES*2];
@@ -39,7 +41,6 @@ DMAChannel AudioOutputPWM::dma(false);
// TODO: this code assumes F_BUS is 48 MHz.
// supporting other speeds is not easy, but should be done someday

#if defined(KINETISK)

void AudioOutputPWM::begin(void)
{
@@ -200,4 +201,203 @@ void AudioOutputPWM::update(void)
if (block) release(block);
}

#elif defined(__IMXRT1062__)

/*
* by Frank B
*/

static const uint8_t silence[2] = {0x80, 0x00};

extern uint8_t analog_write_res;
extern const struct _pwm_pin_info_struct pwm_pin_info[];
audio_block_t * AudioOutputPWM::block = NULL;
DMAMEM __attribute__((aligned(32))) static uint16_t pwm_tx_buffer[2][AUDIO_BLOCK_SAMPLES * 2];
DMAChannel AudioOutputPWM::dma[2](false);
_audio_info_flexpwm AudioOutputPWM::apins[2];

FLASHMEM
void AudioOutputPWM::begin(void) { begin(3, 4); }
FLASHMEM
void AudioOutputPWM::begin(uint8_t pin1, uint8_t pin2)
{
analogWriteResolution(8);
const uint8_t pins[2] = {pin1, pin2};

for (unsigned i = 0; i < 2; i++) {

// use the existing code here:
analogWriteFrequency(pins[i], AUDIO_SAMPLE_RATE_EXACT);
analogWrite(pins[i], silence[i]);

//Fill structure
apins[i].pin = pins[i];
apins[i].info = pwm_pin_info[apins[i].pin];

uint8_t dmamux_source;

if (apins[i].info.type == 1) { //only for valid flexPWM pin:
unsigned module = (apins[i].info.module >> 4) & 3;
unsigned submodule = apins[i].info.module & 3;
switch (module) {
case 0: {
apins[i].flexpwm = &IMXRT_FLEXPWM1;
switch (submodule) {
case 0: dmamux_source = DMAMUX_SOURCE_FLEXPWM1_WRITE0; break;
case 1: dmamux_source = DMAMUX_SOURCE_FLEXPWM1_WRITE1; break;
case 2: dmamux_source = DMAMUX_SOURCE_FLEXPWM1_WRITE2; break;
default: dmamux_source = DMAMUX_SOURCE_FLEXPWM1_WRITE3;
}
break;
}
case 1: {
apins[i].flexpwm = &IMXRT_FLEXPWM2;
switch (submodule) {
case 0: dmamux_source = DMAMUX_SOURCE_FLEXPWM2_WRITE0; break;
case 1: dmamux_source = DMAMUX_SOURCE_FLEXPWM2_WRITE1; break;
case 2: dmamux_source = DMAMUX_SOURCE_FLEXPWM2_WRITE2; break;
default: dmamux_source = DMAMUX_SOURCE_FLEXPWM2_WRITE3;
}
break;
}
case 2: {
apins[i].flexpwm = &IMXRT_FLEXPWM3;
switch (submodule) {
case 0: dmamux_source = DMAMUX_SOURCE_FLEXPWM3_WRITE0; break;
case 1: dmamux_source = DMAMUX_SOURCE_FLEXPWM3_WRITE1; break;
case 2: dmamux_source = DMAMUX_SOURCE_FLEXPWM3_WRITE2; break;
default: dmamux_source = DMAMUX_SOURCE_FLEXPWM3_WRITE3;
}
break;
}
default: {
apins[i].flexpwm = &IMXRT_FLEXPWM4;
switch (submodule) {
case 0: dmamux_source = DMAMUX_SOURCE_FLEXPWM4_WRITE0; break;
case 1: dmamux_source = DMAMUX_SOURCE_FLEXPWM4_WRITE1; break;
case 2: dmamux_source = DMAMUX_SOURCE_FLEXPWM4_WRITE2; break;
default: dmamux_source = DMAMUX_SOURCE_FLEXPWM4_WRITE3;
}
}
}

volatile uint16_t *valReg;
switch (apins[i].info.channel) {
case 0: valReg = &apins[i].flexpwm->SM[submodule].VAL0; break;
case 1: valReg = &apins[i].flexpwm->SM[submodule].VAL3; break;
default: valReg = &apins[i].flexpwm->SM[submodule].VAL5; break;
}

dma[i].begin(true);
dma[i].TCD->SADDR = &pwm_tx_buffer[i][0];
dma[i].TCD->SOFF = 2;
dma[i].TCD->ATTR = DMA_TCD_ATTR_SSIZE(1) | DMA_TCD_ATTR_DSIZE(1);
dma[i].TCD->NBYTES_MLNO = 2;
dma[i].TCD->SLAST = -sizeof(pwm_tx_buffer[0]);
dma[i].TCD->DOFF = 0;
dma[i].TCD->CITER_ELINKNO = sizeof(pwm_tx_buffer[0]) / 2;
dma[i].TCD->DLASTSGA = 0;
dma[i].TCD->BITER_ELINKNO = sizeof(pwm_tx_buffer[0]) / 2;
dma[i].TCD->DADDR = valReg;
dma[i].triggerAtHardwareEvent(dmamux_source);
if (i == 1) { //One interrupt only
dma[i].TCD->CSR = DMA_TCD_CSR_INTHALF | DMA_TCD_CSR_INTMAJOR;
dma[i].attachInterrupt(isr);
}

//set PWM-DMA-Enable
apins[i].flexpwm->SM[submodule].DMAEN = FLEXPWM_SMDMAEN_VALDE;

//clear inital dma data:
uint32_t modulo = apins[i].flexpwm->SM[apins[i].info.module & 3].VAL1;
for (unsigned j=0; j<AUDIO_BLOCK_SAMPLES * 2; j++) {
uint32_t cval = (silence[i] * (modulo + 1)) >> analog_write_res;
if (cval > modulo) cval = modulo;
pwm_tx_buffer[i][j] = cval;
}
arm_dcache_flush_delete(&pwm_tx_buffer[i][0], sizeof(pwm_tx_buffer[0]) / 2 );
}
}

dma[0].enable();
dma[1].enable();
update_responsibility = update_setup();
//pinMode(13,OUTPUT);
}

void AudioOutputPWM::isr(void)
{
dma[1].clearInterrupt();

uint16_t *dest, *dest1;

uint32_t saddr = (uint32_t)(dma[0].TCD->SADDR);
if (saddr < (uint32_t)&pwm_tx_buffer[0][AUDIO_BLOCK_SAMPLES]) {
// DMA is transmitting the first half of the buffer
// so we must fill the second half
dest = &pwm_tx_buffer[0][AUDIO_BLOCK_SAMPLES];
dest1 = &pwm_tx_buffer[1][AUDIO_BLOCK_SAMPLES];
} else {
// DMA is transmitting the second half of the buffer
// so we must fill the first half
dest = &pwm_tx_buffer[0][0];
dest1 = &pwm_tx_buffer[1][0];
}

const uint32_t modulo[2] = { apins[0].flexpwm->SM[apins[0].info.module & 3].VAL1, apins[1].flexpwm->SM[apins[1].info.module & 3].VAL1};

if (block) {

for (unsigned i=0; i < AUDIO_BLOCK_SAMPLES; i++) {
uint32_t sample = (uint16_t)block->data[i] + 0x8000;
uint32_t msb = ((sample >> 8) & 255)/* + 120 ???*/;
uint32_t cval0 = (msb * (modulo[0] + 1)) >> analog_write_res;
if (cval0 > modulo[0]) cval0 = modulo[0]; // TODO: is this check correct?
*dest++ = cval0;
uint32_t lsb = sample & 255;
uint32_t cval1 = (lsb * (modulo[1] + 1)) >> analog_write_res;
if (cval1 > modulo[1]) cval1 = modulo[1];
*dest1++ = cval1;
}
arm_dcache_flush_delete(dest, sizeof(pwm_tx_buffer[0]) / 2 );
arm_dcache_flush_delete(dest1, sizeof(pwm_tx_buffer[1]) / 2 );
AudioStream::release(block);
block = NULL;
} else {
//Serial.println(".");

// fill with silence when no data available
uint32_t cval0 = (silence[0] * (modulo[0] + 1)) >> analog_write_res;
if (cval0 > modulo[0]) cval0 = modulo[0];

uint32_t cval1 = (silence[1] * (modulo[1] + 1)) >> analog_write_res;
if (cval1 > modulo[1]) cval1 = modulo[1];

for (unsigned i=0; i < AUDIO_BLOCK_SAMPLES / 2; i++) {
*dest++ = cval0;
*dest++ = cval0;
*dest1++ = cval1;
*dest1++ = cval1;
}

arm_dcache_flush_delete(dest, sizeof(pwm_tx_buffer[0]) / 2 );
arm_dcache_flush_delete(dest1, sizeof(pwm_tx_buffer[1]) / 2 );
}

AudioStream::update_all();
//digitalWriteFast(13, !digitalRead(13));
}

void AudioOutputPWM::update(void)
{
audio_block_t *tblock;
tblock = receiveReadOnly();
if (!tblock) return;
__disable_irq();
block = tblock;
__enable_irq();
}
#endif

+ 28
- 4
output_pwm.h View File

@@ -31,21 +31,45 @@
#include "AudioStream.h"
#include "DMAChannel.h"

#if defined(__IMXRT1062__)
struct _pwm_pin_info_struct {
uint8_t type; // 0=no pwm, 1=flexpwm, 2=quad
uint8_t module; // 0-3, 0-3
uint8_t channel; // 0=X, 1=A, 2=B
uint8_t muxval; //
};
struct _audio_info_flexpwm {
IMXRT_FLEXPWM_t *flexpwm;
_pwm_pin_info_struct info;
uint8_t pin;
};
#endif

class AudioOutputPWM : public AudioStream
{
public:
AudioOutputPWM(void) : AudioStream(1, inputQueueArray) { begin(); }
virtual void update(void);
private:
static bool update_responsibility;
audio_block_t *inputQueueArray[1];
static void isr(void);
void begin(void);
#if defined(KINETISK)
static audio_block_t *block_1st;
static audio_block_t *block_2nd;
static uint32_t block_offset;
static bool update_responsibility;
static uint8_t interrupt_count;
audio_block_t *inputQueueArray[1];
static DMAChannel dma;
static void isr(void);
void begin(void);
#elif defined(__IMXRT1062__)
public:
AudioOutputPWM(uint8_t pin1, uint8_t pin2) : AudioStream(1, inputQueueArray) { begin(pin1, pin2); }
private:
void begin(uint8_t pin1, uint8_t pin2); //FlexPWM pins only
static audio_block_t *block;
static DMAChannel dma[2];
static _audio_info_flexpwm apins[2];
#endif
};

#endif

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