const int outputPin1 = 9; // choose the output pin number for PWM output 1
const int outputPin2 = 10; // choose the output pin number for PWM output 2
const int pwmSteps = 255; // set the number of PWM steps for full range
const int pwmIncrement = 5; // set the PWM increment for each step

unsigned long previousMillis1 = 0;
unsigned long previousMillis2 = 0;

void setup() {
  pinMode(outputPin1, OUTPUT);
  pinMode(outputPin2, OUTPUT);
}

void loop() {
  rampUpDownOutput1(outputPin1, 10); // ramp up and down PWM output 1 with a time interval of 10 milliseconds
  pulseOutput2(outputPin2, 500); // pulse PWM output 2 with a time interval of 500 milliseconds
}

void rampUpDownOutput1(int outputPin, unsigned long interval) {
  static int pwmValue = 0;
  static bool rampUp = true;
  
  unsigned long currentMillis = millis();
  if (currentMillis - previousMillis1 >= interval) {
    previousMillis1 = currentMillis;

    if (rampUp) {
      pwmValue += pwmIncrement;
      if (pwmValue >= pwmSteps) {
        pwmValue = pwmSteps;
        rampUp = false;
      }
    } else {
      pwmValue -= pwmIncrement;
      if (pwmValue <= 0) {
        pwmValue = 0;
        rampUp = true;
      }
    }
    
    analogWrite(outputPin, pwmValue);
  }
}

void pulseOutput2(int outputPin, unsigned long interval) {
  static bool pulseState = false;
  
  unsigned long currentMillis = millis();
  if (currentMillis - previousMillis2 >= interval) {
    previousMillis2 = currentMillis;

    pulseState = !pulseState;
    int pulseValue = pulseState ? pwmSteps : 0;
    analogWrite(outputPin, pulseValue);
  }
}