// Pin Definitions
const int analogPin = A0;    // Potentiometer connected to A0
const int ledPin = 9;        // LED connected to PWM pin 9

int adcValue = 0;            // Variable to store ADC value
int ledBrightness = 0;       // Variable for LED brightness

void setup() {
  // Set pin 9 as output for PWM
  DDRB |= (1 << PB1);  // Set pin 9 (PB1) as output
  
  // Initialize Timer1 for Fast PWM mode
  TCCR1A = (1 << COM1A1) | (1 << WGM11) | (1 << WGM10);  // Fast PWM mode, non-inverted
  TCCR1B = (1 << WGM12) | (1 << CS11);  // Prescaler = 8, Fast PWM mode
  
  // Start serial communication for debugging
  Serial.begin(9600);
}

void loop() {
  // Start ADC conversion for channel A0
  ADMUX = (1 << MUX0);  // Select channel A0 (pin 0)
  ADCSRA |= (1 << ADSC); // Start ADC conversion
  
  // Wait until conversion is complete
  while (ADCSRA & (1 << ADSC));
  
  // Get ADC result from the ADC Data Register (ADCL and ADCH)
  adcValue = ADC; 
  
  // Map ADC value (0-1023) to PWM range (0-255)
  ledBrightness = (adcValue * 255) / 1023;

  // Set PWM duty cycle for LED on pin 9
  OCR1A = ledBrightness;  // Update the PWM duty cycle
  
  // Print ADC and LED brightness values to Serial Monitor for debugging
  Serial.print("ADC Value: ");
  Serial.print(adcValue);
  Serial.print(" | LED Brightness: ");
  Serial.println(ledBrightness);

  // Small delay for stability
  delay(100);  
}