const int redPin = PA1;
const int greenPin = PA2;
const int bluePin = PA13;

int r = 0, g = 0, b = 0; // Store RGB values

void setup() {
  pinMode(redPin, OUTPUT);
  pinMode(greenPin, OUTPUT);
  pinMode(bluePin, OUTPUT);
  Serial.begin(115200);
  Serial.println("RGB Controller Ready. Send commands like 'R255', 'G100', 'B000'.");
}

void loop() {
  // Check if a command is waiting. We look for 4 bytes: Letter, 3 digits.
  if (Serial.available() >= 4) {
    char color = Serial.read(); // Read the first character (R, G, or B)
    // Read the next 3 characters and convert them from text to an integer
    String valueStr = "";
    for (int i = 0; i < 3; i++) {
      valueStr += (char)Serial.read();
    }
    int value = valueStr.toInt(); // Convert string "255" to integer 255

    // Assign the value to the correct color variable
    switch (color) {
      case 'R': r = value; break;
      case 'G': g = value; break;
      case 'B': b = value; break;
      default: Serial.println("Error: First char must be R, G, or B."); return;
    }

    // Print what we received and update the LED
    Serial.print("Set ");
    Serial.print(color);
    Serial.print(" to ");
    Serial.println(value);

    analogWrite(redPin, r);   // Control LED brightness (PWM)
    analogWrite(greenPin, g);
    analogWrite(bluePin, b);
  }
}