// STM32 Nucleo C031C6
// Multiple LED Blinking
// D2, D3, D4 and D5 are used

#define LED1 D2
#define LED2 D3
#define LED3 D4
#define LED4 D5

void setup() {
  pinMode(LED1, OUTPUT);
  pinMode(LED2, OUTPUT);
  pinMode(LED3, OUTPUT);
  pinMode(LED4, OUTPUT);
}

void loop() {

  // All LEDs ON
  digitalWrite(LED1, HIGH);
  digitalWrite(LED2, HIGH);
  digitalWrite(LED3, HIGH);
  digitalWrite(LED4, HIGH);

  delay(500);

  // All LEDs OFF
  digitalWrite(LED1, LOW);
  digitalWrite(LED2, LOW);
  digitalWrite(LED3, LOW);
  digitalWrite(LED4, LOW);

  delay(500);
}