RIOT/tests/sys_arduino_analog/arduino-test.sketch

// Example sketch given in analogWrite documentation
// https://www.arduino.cc/reference/en/language/functions/analog-io/analogwrite/

int ledPin = LED_PIN;         // LED connected to digital pin 3 by default
int analogPin = 1;            // potentiometer connected to analog pin 1
int val = 0;                  // variable to store the read value

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

void loop() {
  val = analogRead(analogPin);  // read the input pin
  analogWrite(ledPin, val / 4); // analogRead values go from 0 to 1023, analogWrite values from 0 to 255
}