#include <math.h>  // For round()
#include "driver/ledc.h"


// --- Configuration Constants ---
const int pwmPin = 13;           // GPIO where LED is connected
const int pwmChannel = 0;        // Use PWM channel 0
const int frequency = 5000;      // 5 kHz PWM frequency
const uint8_t resolution = 8;    // 8-bit resolution (0-255)

// Duty cycle in percentage
const float fixedDutyCyclePercent = 75.0;

// Calculate max duty cycle value
const uint32_t maxDutyCycle = (1 << resolution) - 1;

// Helper: Convert percentage to raw duty cycle
uint32_t percentageToDuty(float percentage) {
  if (percentage < 0.0) percentage = 0.0;
  if (percentage > 100.0) percentage = 100.0;

  return (uint32_t)round((percentage / 100.0) * maxDutyCycle);
}

void setup() {
  Serial.begin(115200);
  Serial.println("ESP32 Fixed PWM (Using Correct API)");

  // Step 1: Configure PWM channel
  ledcSetup(pwmChannel, frequency, resolution);

  // Step 2: Attach PWM channel to pin
  ledcAttachPin(pwmPin, pwmChannel);

  // Step 3: Set duty cycle
  uint32_t duty = percentageToDuty(fixedDutyCyclePercent);
  ledcWrite(pwmChannel, duty);

  Serial.printf("PWM setup complete on pin %d with %.1f%% duty cycle\n", pwmPin, fixedDutyCyclePercent);
}

void loop() {
  // Nothing needed in loop for fixed output
  delay(1000);
}