PWMComplementaryDriverESP32.h

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#pragma once
#ifdef ESP32
#include "AudioTools/CoreAudio/AudioPWM/PWMDriverBase.h"
#include "driver/mcpwm.h"
 
namespace audio_tools {
 
struct PinInfoESP32Compl {
  int gpio_high;          // high-side pin (PWMxA)
  int gpio_low;           // low-side pin (PWMxB)
  mcpwm_unit_t unit;      // 0..1
  mcpwm_timer_t timer;    // 0..2
};
 
class PWMComplementaryDriverESP32 : public DriverPWMBase {
 public:
  // friend void pwm_callback(void*ptr);
 
  PWMComplementaryDriverESP32() { TRACED(); }
 
  // Ends the output
  virtual void end() {
    TRACED();
    timer.end();
    is_timer_started = false;
    for (int j = 0; j < pins.size(); j++) {
      mcpwm_stop(pins[j].unit, pins[j].timer);
    }
    deleteBuffer();
  }
 
  virtual void startTimer() {
    if (!timer) {
      TRACEI();
      timer.begin(pwm_callback, effectiveOutputSampleRate(), HZ);
      actual_timer_frequency = effectiveOutputSampleRate();
      is_timer_started = true;
    }
  }
 
  virtual void setupPWM() {
    // frequency is driven by selected resolution
    if (audio_config.pwm_frequency == 0) {
      audio_config.pwm_frequency = frequency(audio_config.resolution) * 1000;
    }
    if (audio_config.channels > maxChannels()) {
      LOGE("Only %d complementary channels supported", maxChannels());
      audio_config.channels = maxChannels();
    }
    bool has_pairs = audio_config.pins().size() >= (size_t)(audio_config.channels * 2);
    if (!has_pairs) {
      LOGW("Expected %d pins for %d complementary channels, got %d - assuming consecutive pin+1 as low-side", audio_config.channels*2, audio_config.channels, audio_config.pins().size());
    }
    pins.resize(audio_config.channels);
    for (int j = 0; j < audio_config.channels; j++) {
      pins[j].unit = (mcpwm_unit_t)(j / 3);
      pins[j].timer = (mcpwm_timer_t)(j % 3);
      if (pins[j].unit > MCPWM_UNIT_1) { LOGE("Too many channels for MCPWM: %d", j); break; }
      if (has_pairs) {
        pins[j].gpio_high = audio_config.pins()[j*2];
        pins[j].gpio_low  = audio_config.pins()[j*2 + 1];
      } else {
        pins[j].gpio_high = audio_config.pins()[j];
        pins[j].gpio_low  = pins[j].gpio_high + 1;
      }
      mcpwm_io_signals_t sigA = (mcpwm_io_signals_t)(MCPWM0A + (pins[j].timer * 2));
      mcpwm_io_signals_t sigB = (mcpwm_io_signals_t)(MCPWM0B + (pins[j].timer * 2));
      esp_err_t err = mcpwm_gpio_init(pins[j].unit, sigA, pins[j].gpio_high);
      if (err != ESP_OK) LOGE("mcpwm_gpio_init high error=%d", (int)err);
      err = mcpwm_gpio_init(pins[j].unit, sigB, pins[j].gpio_low);
      if (err != ESP_OK) LOGE("mcpwm_gpio_init low error=%d", (int)err);
      mcpwm_config_t cfg; cfg.frequency = audio_config.pwm_frequency; cfg.cmpr_a = 0; cfg.cmpr_b = 0; cfg.counter_mode = MCPWM_UP_COUNTER; cfg.duty_mode = MCPWM_DUTY_MODE_0;
      err = mcpwm_init(pins[j].unit, pins[j].timer, &cfg);
      if (err != ESP_OK) LOGE("mcpwm_init error=%d", (int)err);
      if (audio_config.dead_time_us > 0) {
        uint32_t dead_ticks = audio_config.dead_time_us * 80u; // 80MHz APB
        uint32_t period_ticks = 80000000UL / audio_config.pwm_frequency;
        if (dead_ticks * 2 >= period_ticks) dead_ticks = period_ticks / 4;
        if (dead_ticks > 0) {
          err = mcpwm_deadtime_enable(pins[j].unit, pins[j].timer, MCPWM_ACTIVE_HIGH_COMPLIMENT_MODE, dead_ticks, dead_ticks);
          if (err != ESP_OK) LOGE("deadtime_enable error=%d", (int)err);
        }
      }
      LOGI("Complementary PWM ch=%d unit=%d timer=%d high=%d low=%d freq=%u dead_us=%u", j,(int)pins[j].unit,(int)pins[j].timer,pins[j].gpio_high,pins[j].gpio_low,(unsigned)audio_config.pwm_frequency,(unsigned)audio_config.dead_time_us);
    }
  }
 
 
  virtual void setupTimer() {
    timer.setCallbackParameter(this);
    timer.setIsSave(false);
 
    if (actual_timer_frequency != effectiveOutputSampleRate()) {
      timer.end();
      startTimer();
    }
  }
 
  virtual void pwmWrite(int channel, int value) {
    if (channel < 0 || channel >= pins.size()) return;
    int duty = (int)((int64_t)value * 100 / maxOutputValue());
    if (duty < 0) duty = 0; else if (duty > 100) duty = 100;
    mcpwm_set_duty(pins[channel].unit, pins[channel].timer, MCPWM_OPR_A, duty);
    mcpwm_set_duty_type(pins[channel].unit, pins[channel].timer, MCPWM_OPR_A, MCPWM_DUTY_MODE_0);
    if (audio_config.dead_time_us == 0) {
      // software complementary: invert
      mcpwm_set_duty(pins[channel].unit, pins[channel].timer, MCPWM_OPR_B, 100 - duty);
      mcpwm_set_duty_type(pins[channel].unit, pins[channel].timer, MCPWM_OPR_B, MCPWM_DUTY_MODE_0);
    }
  }
 
 protected:
  Vector<PinInfoESP32Compl> pins;
  TimerAlarmRepeating timer;
  uint32_t actual_timer_frequency = 0;
 
  int maxUnsignedValue(int resolution) { return pow(2, resolution); }
 
  virtual int maxChannels() { return 6; };
 
  virtual int maxOutputValue() {
    return maxUnsignedValue(audio_config.resolution);
  }
 
  float frequency(int resolution) {
// On ESP32S2 and S3, the frequncy seems off by a factor of 2
#if defined(ESP32S2) || defined(ESP32S3)
    switch (resolution) {
      case 7:
        return 312.5;
      case 8:
        return 156.25;
      case 9:
        return 78.125;
      case 10:
        return 39.0625;
      case 11:
        return 19.53125;
    }
    return 312.5;
#else
    switch (resolution) {
      case 8:
        return 312.5;
      case 9:
        return 156.25;
      case 10:
        return 78.125;
      case 11:
        return 39.0625;
    }
    return 312.5;
#endif
  }
 
  static void pwm_callback(void *ptr) {
    PWMComplementaryDriverESP32 *drv = (PWMComplementaryDriverESP32 *)ptr;
    if (drv != nullptr) {
      drv->playNextFrame();
    }
  }
};
 
}  // namespace audio_tools
 
#endif