Blink Fade without delay

blink_fade.ino

const byte ledPin =  13;      // the number of the LED pin
const byte fadeLed = 11;

// Variables will change :
int ledState = LOW;             // ledState used to set the LED

// Generally, you shuould use "unsigned long" for variables that hold time
// The value will quickly become too large for an int to store
unsigned long previousMillis = 0;        // will store last time LED was updated

unsigned long fadeLast = 0;
const long fadeInterval = 30;

// constants won't change :
const long interval = 1000;           // interval at which to blink (milliseconds)

byte fadeDirection = 0;
int fadeValue = 0;

void setup() {
  // set the digital pin as output:
  pinMode(ledPin, OUTPUT);
}

void loop()
{
  // here is where you'd put code that needs to be running all the time.

  // check to see if it's time to blink the LED; that is, if the
  // difference between the current time and last time you blinked
  // the LED is bigger than the interval at which you want to
  // blink the LED.
  unsigned long currentMillis = millis();
 
  if(currentMillis - previousMillis >= interval) {
    // save the last time you blinked the LED 
    previousMillis = currentMillis;   

    // if the LED is off turn it on and vice-versa:
    if (ledState == LOW)
      ledState = HIGH;
    else
      ledState = LOW;

    // set the LED with the ledState of the variable:
    digitalWrite(ledPin, ledState);
  }
  
  if(currentMillis - fadeLast >= fadeInterval) {
    fadeLast = currentMillis;  
    
    if (fadeDirection == 0) {
      fadeValue += 5;
      if (fadeValue >= 251) {
        fadeDirection = 1;
        fadeValue = 255;
      }
    } else if (fadeDirection == 1) {
      fadeValue -= 5;
      if (fadeValue <= 5) {
        fadeDirection = 0;
        fadeValue = 0;
      }
    }
    analogWrite(fadeLed, fadeValue);
    
  }

}