clignotante.py
The first MicroPython program: the LED blinks once per second with serial console tracing. It shows Pin as output, value() and time.sleep, the basis of every embedded script on the board.
Hardware
A Raspberry Pi Pico (RP2040 dual Cortex-M0+ @ 133 MHz) with MicroPython installed, powered over USB. No external part (external LED + 330 Ω resistor only if the user LED is unavailable).
Wiring
Nothing to wire: the user LED sits on GP25. For an external LED: any GP pin through a 330 Ω resistor to GND.
How it works
Pin(LED_PIN, Pin.OUT) sets the pin as output. The infinite loop alternates value(1)/value(0) with a one-second pause; print() goes to the USB serial (Thonny).
Running it
Install MicroPython if needed (hold BOOTSEL, plug USB, drop the .uf2 file), then copy the script to the board drive or via Thonny. The script auto-starts when named main.py.
Variants
Save as main.py for auto-start, or replace sleep(1) with sleep_ms(100) for fast blinking.
clignotante.py
# Clignotement d'une LED avec MicroPython (module machine.Pin).
# LED utilisateur integree (GP25 sur la majorite des cartes)
from machine import Pin
import time
LED_PIN = 25
led = Pin(LED_PIN, Pin.OUT) # broche en sortie numerique
print("Clignotement demarre sur GP" + str(LED_PIN))
compteur = 0
while True:
led.value(1) # LED allumee
compteur += 1
print("LED ON (cycle %d)" % compteur)
time.sleep(1) # 1 seconde
led.value(0) # LED eteinte
print("LED OFF")
time.sleep(1)
# Pour arreter : bouton Stop dans Thonny (le script tourne aussi
# tout seul s'il est enregistre sous main.py sur la carte).