Blinky on Arduino Nano 33 BLE Sense board

void setup() {
  pinMode(LED_BUILTIN, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  Serial.println("HIGH");
  digitalWrite(LED_BUILTIN, HIGH);
  delay(1000);

  Serial.println("LOW");
  digitalWrite(LED_BUILTIN, LOW);
  delay(1000);
}

BOARD?=arduino:mbed:nano33ble
PORT?=/dev/cu.usbmodem14*
BUILD=build

.PHONY: default lint all flash clean

default: lint all flash clean

lint:
	cpplint --extensions=ino --filter=-legal/copyright *.ino

all:
	arduino-cli compile --fqbn $(BOARD) --output-dir $(BUILD) ./

flash:
	arduino-cli upload --fqbn $(BOARD) --port $(PORT) --input-dir $(BUILD)

clean:
	rm -r build