🛠 Faire clignoter la LED builtin (broche 13)

Objectives

Discover the Arduino Nano Every — ATmega4809 clocked at 20 MHz, 48 KB of flash, 6 KB of RAM — by blinking the built-in LED on pin 13 (LED_BUILTIN), with no external wiring. This is the getting-started tutorial: it validates the entire chain IDE → cable → USB serial bridge → bootloader → program.

Hardware

• 1 × Arduino Nano Every
• 1 × micro-USB data cable (not a charge-only cable)
• PC with the Arduino IDE and the Arduino core package including the "Arduino Nano Every" board (megaAVR core, the same as the Uno WiFi Rev2)

Complete code

// Clignotement de la LED builtin — broche 13 sur Nano Every
const uint8_t LED = LED_BUILTIN; // 13 sur cette carte

void setup {
  pinMode(LED, OUTPUT);
}

void loop {
  digitalWrite(LED, HIGH);
  delay(500);
  digitalWrite(LED, LOW);
  delay(500);
}

Expected verification

In the IDE, select "Arduino Nano Every" under Tools > Board, then the COM port that appeared. After uploading, LED 13 blinks every 500 ms. The USB serial port is provided by an onboard bridge module (not a classic FTDI/CH340 chip): the port must remain visible in the serial monitor even when the code prints nothing.

Common errors

• Charge-only USB cable: the COM port never appears — test with another cable.
• Wrong board type: "Arduino Nano" (classic, ATmega328P) instead of "Nano Every" causes the upload to fail.
• The "1200 bauds then reset" reflex of the classic Nano (FTDI chip) does not apply here: the Every uses a serial bootloader via its bridge module; if an old tutorial recommends this, ignore it.

• The LED blinks but the serial monitor is empty: normal, this code prints nothing; move on to the Serial tutorial.