/* Blink an LED without using delay() */

#define LED 9
#define BUTTON 12

unsigned long timeOn = 500;
unsigned long changeTime = 0;

void setup() {
  pinMode(LED, OUTPUT);
  pinMode(BUTTON, INPUT_PULLUP);

}

unsigned char ledValue = 0;
void loop() {
  if (millis() >= changeTime)  {
    ledValue = !ledValue;
    analogWrite(LED, ledValue);
    changeTime = millis() + timeOn;
  }

  if (digitalRead(BUTTON) == 0) {
    ledValue = ledValue + 20;
    if (ledValue > 240) {
      ledValue = 0;
    }
  }
}