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Add PWM support for NRF52
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- Give up on I2S playback and resort to PWM
- Very basic mock-up, 16-bit audio at 16khz cannot be modified currently
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@TMRh20
TMRh20 committed Dec 17, 2023
1 parent fcb2323 commit 9aaf553
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Showing 2 changed files with 86 additions and 38 deletions.
10 changes: 8 additions & 2 deletions src/AutoAnalogAudio.h
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Original file line number Diff line number Diff line change
Expand Up @@ -29,6 +29,7 @@
#include "driver/i2s.h"
#endif


#define AAA_CHANNEL0 0
#define AAA_CHANNEL1 1
#define AAA_MODE_STEREO 2
Expand Down Expand Up @@ -99,7 +100,7 @@ class AutoAnalog
* 10 or 12-bit samples are read directly from this buffer after calling getADC() <br>
* @see adcBitsPerSample
*/
#if !defined(ARDUINO_ARCH_NRF52840)
#if !defined(ARDUINO_ARCH_NRF52840) && !defined (ARDUINO_ARCH_NRF52) || defined ARDUINO_NRF52840_FEATHER
uint16_t adcBuffer16[MAX_BUFFER_SIZE];
#else
inline static int16_t adcBuffer16[MAX_BUFFER_SIZE];
Expand Down Expand Up @@ -188,7 +189,7 @@ class AutoAnalog

/**@}*/

#if defined (ARDUINO_ARCH_NRF52840)
#if defined (ARDUINO_ARCH_NRF52840) || defined (ARDUINO_ARCH_NRF52) && !defined ARDUINO_NRF52840_FEATHER
inline static uint8_t aCtr;
inline static uint32_t aSize;
inline static uint16_t *buf0 = NULL;
Expand All @@ -207,6 +208,11 @@ class AutoAnalog
inline static uint32_t sampleCounter;
#endif

#if defined ARDUINO_NRF52840_FEATHER
uint16_t dacBuf0[MAX_BUFFER_SIZE];
uint16_t dacBuf1[MAX_BUFFER_SIZE];
#endif

private:

/**
Expand Down
114 changes: 78 additions & 36 deletions src/NRF52840/AutoAnalogAudio.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -18,20 +18,22 @@

/****************************************************************************/

#if defined (ARDUINO_ARCH_NRF52840)
#if defined (ARDUINO_ARCH_NRF52840) || defined (ARDUINO_ARCH_NRF52)

#include "../AutoAnalogAudio.h"
#include <hal/nrf_pdm.h>
#include <hal/nrf_i2s.h>

#define PDM_IRQ_PRIORITY 7
#define NRF_PDM_FREQ_1280K (nrf_pdm_freq_t)(0x0A000000UL) ///< PDM_CLK= 1.280 MHz (32 MHz / 25) => Fs= 20000 Hz
#define DEFAULT_PDM_GAIN 20
#define PIN_MCK (13)
#define PIN_SCK (14)
#define PIN_LRCK (15)
#define PIN_SDOUT (2)

#if !defined ARDUINO_NRF52840_FEATHER
#define PDM_IRQ_PRIORITY 7
#define NRF_PDM_FREQ_1280K (nrf_pdm_freq_t)(0x0A000000UL) ///< PDM_CLK= 1.280 MHz (32 MHz / 25) => Fs= 20000 Hz
#define DEFAULT_PDM_GAIN 20
#endif
#define PIN_MCK 12//(13)
#define PIN_SCK 13//(14)
#define PIN_LRCK 14//(15)
#define PIN_SDOUT (28)
#define DEFAULT_PWM_PIN 5
/****************************************************************************/
/* Public Functions */
/****************************************************************************/
Expand All @@ -44,26 +46,29 @@
//int16_t sine_table[] = { 0, 0, 23170, 23170, 32767, 32767, 23170, 23170, 0, 0, -23170, -23170, -32768, -32768, -23170, -23170};

AutoAnalog::AutoAnalog(){

#if !defined ARDUINO_NRF52840_FEATHER
adcReady = false;
adcBitsPerSample = 8;
#endif
dacBitsPerSample = 8;
autoAdjust = true;
for(int i=0; i<MAX_BUFFER_SIZE; i++){
dacBuffer[i] = 0;
}

#if !defined ARDUINO_NRF52840_FEATHER
aSize = MAX_BUFFER_SIZE;//&buf_size;
buf0 = &adcBuf0[0];
buf1 = &adcBuf1[0];
aCtr = 0;
micOn = 0;
sampleCounter = 0;
#endif
}

void AutoAnalog::begin(bool enADC, bool enDAC){

#if !defined ARDUINO_NRF52840_FEATHER
if(enADC){

set_callback(adcCallback);
Expand All @@ -81,6 +86,7 @@ void AutoAnalog::begin(bool enADC, bool enDAC){
//Set default 16khz sample rate
NRF_PDM->RATIO = ((PDM_RATIO_RATIO_Ratio80 << PDM_RATIO_RATIO_Pos) & PDM_RATIO_RATIO_Msk);
nrf_pdm_clock_set(NRF_PDM_FREQ_1280K);
//nrf_pdm_clock_set(NRF_PDM_FREQ_1032K);
//nrf_pdm_clock_set(NRF_PDM_FREQ_1067K);
// NRF_PDM_FREQ_1000K = PDM_PDMCLKCTRL_FREQ_1000K, ///< PDM_CLK = 1.000 MHz.
// NRF_PDM_FREQ_1032K = PDM_PDMCLKCTRL_FREQ_Default, ///< PDM_CLK = 1.032 MHz.
Expand Down Expand Up @@ -128,30 +134,30 @@ void AutoAnalog::begin(bool enADC, bool enDAC){

//Serial.println("ADC START");



}

#endif


if(enDAC){
// Enable transmission
NRF_I2S->CONFIG.TXEN = (I2S_CONFIG_TXEN_TXEN_ENABLE << I2S_CONFIG_TXEN_TXEN_Pos);
/*NRF_I2S->CONFIG.TXEN = (I2S_CONFIG_TXEN_TXEN_ENABLE << I2S_CONFIG_TXEN_TXEN_Pos);
// Enable MCK generator
NRF_I2S->CONFIG.MCKEN = (I2S_CONFIG_MCKEN_MCKEN_ENABLE << I2S_CONFIG_MCKEN_MCKEN_Pos);
// MCKFREQ = 4 MHz
//NRF_I2S->CONFIG.MCKFREQ = I2S_CONFIG_MCKFREQ_MCKFREQ_32MDIV11 << I2S_CONFIG_MCKFREQ_MCKFREQ_Pos;
NRF_I2S->CONFIG.MCKFREQ = I2S_CONFIG_MCKFREQ_MCKFREQ_32MDIV63 << I2S_CONFIG_MCKFREQ_MCKFREQ_Pos;
NRF_I2S->CONFIG.MCKFREQ = I2S_CONFIG_MCKFREQ_MCKFREQ_32MDIV31 << I2S_CONFIG_MCKFREQ_MCKFREQ_Pos;
//NRF_I2S->CONFIG.MCKFREQ = I2S_CONFIG_MCKFREQ_MCKFREQ_32MDIV63 << I2S_CONFIG_MCKFREQ_MCKFREQ_Pos;
// Ratio = 64
NRF_I2S->CONFIG.RATIO = I2S_CONFIG_RATIO_RATIO_64X << I2S_CONFIG_RATIO_RATIO_Pos;
//NRF_I2S->CONFIG.RATIO = I2S_CONFIG_RATIO_RATIO_256X << I2S_CONFIG_RATIO_RATIO_Pos;
// Master mode, 16Bit, left aligned
NRF_I2S->CONFIG.MODE = I2S_CONFIG_MODE_MODE_MASTER << I2S_CONFIG_MODE_MODE_Pos;
NRF_I2S->CONFIG.SWIDTH = I2S_CONFIG_SWIDTH_SWIDTH_8BIT << I2S_CONFIG_SWIDTH_SWIDTH_Pos;
NRF_I2S->CONFIG.SWIDTH = I2S_CONFIG_SWIDTH_SWIDTH_16BIT << I2S_CONFIG_SWIDTH_SWIDTH_Pos;
NRF_I2S->CONFIG.ALIGN = I2S_CONFIG_ALIGN_ALIGN_LEFT << I2S_CONFIG_ALIGN_ALIGN_Pos;
// Format = I2S
Expand All @@ -166,16 +172,35 @@ void AutoAnalog::begin(bool enADC, bool enDAC){
NRF_I2S->PSEL.LRCK = (PIN_LRCK << I2S_PSEL_LRCK_PIN_Pos);
NRF_I2S->PSEL.SDOUT = (PIN_SDOUT << I2S_PSEL_SDOUT_PIN_Pos);
NRF_I2S->ENABLE = 1;
// Configure data pointer
NRF_I2S->TXD.PTR = (uint32_t)&dacBuf0[0];
NRF_I2S->TXD.PTR = (uint32_t)dacBuf0;
NRF_I2S->RXD.PTR = (uint32_t)dacBuf1;
NRF_I2S->RXTXD.MAXCNT = MAX_BUFFER_SIZE / sizeof(uint32_t);
//NRF_I2S->TXD.PTR = (uint32_t)&sine_table[0];
//NRF_I2S->RXTXD.MAXCNT = sizeof(sine_table) / sizeof(uint32_t);

NRF_I2S->ENABLE = 1;
// Start transmitting I2S data
NRF_I2S->TASKS_START = 1;
NRF_I2S->TASKS_START = 1;*/

pinMode(DEFAULT_PWM_PIN,OUTPUT);
digitalWrite(DEFAULT_PWM_PIN,LOW);

NRF_PWM0->PSEL.OUT[0] = (DEFAULT_PWM_PIN << PWM_PSEL_OUT_PIN_Pos) | (PWM_PSEL_OUT_CONNECT_Connected << PWM_PSEL_OUT_CONNECT_Pos);
NRF_PWM0->ENABLE = (PWM_ENABLE_ENABLE_Enabled << PWM_ENABLE_ENABLE_Pos);
NRF_PWM0->MODE = (PWM_MODE_UPDOWN_Up << PWM_MODE_UPDOWN_Pos);
NRF_PWM0->PRESCALER = (PWM_PRESCALER_PRESCALER_DIV_1 << PWM_PRESCALER_PRESCALER_Pos);
NRF_PWM0->COUNTERTOP = (1000 << PWM_COUNTERTOP_COUNTERTOP_Pos); //1 msec
NRF_PWM0->LOOP = (1 << PWM_LOOP_CNT_Pos);
NRF_PWM0->DECODER = (PWM_DECODER_LOAD_Common << PWM_DECODER_LOAD_Pos) | (PWM_DECODER_MODE_RefreshCount << PWM_DECODER_MODE_Pos);
NRF_PWM0->SEQ[0].PTR = ((uint32_t)(&dacBuf0[0]) << PWM_SEQ_PTR_PTR_Pos);
NRF_PWM0->SEQ[0].CNT = ((sizeof(dacBuf0) / sizeof(uint16_t)) << PWM_SEQ_CNT_CNT_Pos);
NRF_PWM0->SEQ[0].REFRESH = 0;
NRF_PWM0->SEQ[0].ENDDELAY = 0;

NRF_PWM0->TASKS_SEQSTART[0] = 1;

}


Expand All @@ -200,46 +225,60 @@ void AutoAnalog::triggerADC(){
/****************************************************************************/

void AutoAnalog::enableAdcChannel(uint8_t pinAx){

#if !defined ARDUINO_NRF52840_FEATHER
nrf_pdm_enable();

#endif
}

/****************************************************************************/

void AutoAnalog::disableAdcChannel(uint8_t pinAx){

#if !defined ARDUINO_NRF52840_FEATHER
nrf_pdm_disable();

#endif
}

/****************************************************************************/

void AutoAnalog::getADC(uint32_t samples){

#if !defined ARDUINO_NRF52840_FEATHER
while(!adcReady){__WFE();};
aSize = samples;
adcReady = false;

#endif
}

/****************************************************************************/
bool dacBufCtr = 0;

void AutoAnalog::feedDAC(uint8_t dacChannel, uint32_t samples, bool startInterrupts){

uint32_t ctr = millis();
/*uint32_t ctr = millis();
while(!nrf_i2s_event_check(NRF_I2S,NRF_I2S_EVENT_TXPTRUPD));//{ if(millis() - ctr > 5){break;}};
nrf_i2s_event_clear(NRF_I2S,NRF_I2S_EVENT_TXPTRUPD);
for(uint32_t i=0; i<samples; i++){
dacBuf0[i] = dacBuffer16[i];
}
//memcpy(dacBuf0, dacBuffer16, samples * 2);
//for(uint32_t i=0; i<samples; i++){
// dacBuf0[i] = dacBuffer16[i];
//}
memcpy(dacBuf0, dacBuffer, samples);
//NRF_I2S->TXD.PTR = (uint32_t)&dacBuf0[0];
//memcpy(&dacBuf[0], &dacBuffer16[0], samples);
NRF_I2S->RXTXD.MAXCNT = samples /4;//sizeof(uint32_t);
nrf_i2s_event_clear(NRF_I2S,NRF_I2S_EVENT_TXPTRUPD);
NRF_I2S->RXTXD.MAXCNT = 8;// * 2 / sizeof(uint32_t);*/
uint32_t timer = millis();
while(NRF_PWM0->EVENTS_SEQEND[0] == 0){
if(millis() - timer > 10){ break; }
NRF_PWM0->EVENTS_SEQEND[0] = 0;
}
memcpy(dacBuf0, dacBuffer16, samples);
NRF_PWM0->SEQ[0].PTR = ((uint32_t)(&dacBuf0[0]) << PWM_SEQ_PTR_PTR_Pos);
NRF_PWM0->SEQ[0].CNT = (samples << PWM_SEQ_CNT_CNT_Pos);
NRF_PWM0->TASKS_SEQSTART[0] = 1;



}

/****************************************************************************/
Expand All @@ -256,6 +295,7 @@ void AutoAnalog::dacBufferStereo(uint8_t dacChannel){

uint32_t AutoAnalog::frequencyToTimerCount(uint32_t frequency){

return 1;
}

/****************************************************************************/
Expand All @@ -281,7 +321,8 @@ void AutoAnalog::dacSetup(void){
/****************************************************************************/

void AutoAnalog::disableDAC(bool withinTask){
NRF_I2S->ENABLE = 0;
//NRF_I2S->ENABLE = 0;
NRF_PWM0->TASKS_STOP = 1;
}

/****************************************************************************/
Expand All @@ -308,7 +349,7 @@ void AutoAnalog::tc2Setup (uint32_t sampRate)
}

/****************************************************************************/

#if !defined ARDUINO_NRF52840_FEATHER
extern "C" {
__attribute__((__used__)) void PDM_IRQHandler_v(void)
{
Expand Down Expand Up @@ -357,4 +398,5 @@ void AutoAnalog::adcCallback(uint16_t *buf, uint32_t buf_len){

adcReady = true;
}
#endif //#if !defined ARDUINO_NRF52840_FEATHER
#endif //#if defined (ARDUINO_ARCH_SAM)

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