🛠 Se connecter à un réseau Wi-Fi (station, WPA2/WPA3)

Objectives

The first real networking step with the Pico W: joining a Wi-Fi access point in station mode. The CYW43439 is a Wi-Fi 4 (802.11n) single-band 2.4 GHz only radio — forget about 5 GHz networks — with WPA3 support. You will use MicroPython's network module (the recommended path in the datasheet: MicroPython is "the fastest way to get code running on Pico W"), understand the active → connect → isconnected cycle, and retrieve the IP address.

Hardware

• 1 × Raspberry Pi Pico W + micro-USB data cable
• MicroPython firmware raspberry_pi_pico_w (_picow build, includes the cyw43 driver)
• A 2.4 GHz access point (WPA2 or WPA3) — no 5 GHz
• Serial console (Thonny, picocom…) at 115200 baud

Complete code

# main.py — connexion Wi-Fi station sur Pico W (MicroPython)
# Sauvegardé sous main.py, il se lance à chaque mise sous tension.
import machine, network, time

def do_connect:
    wlan = network.WLAN          # interface station (par défaut)
    wlan.active(True)              # alimente l'interface du CYW43439
    if not wlan.isconnected:
        print('connecting to network...')
        wlan.connect('my_ssid', 'my_password')   # identifiants WPA2/WPA3
        while not wlan.isconnected:
            machine.idle         # dort entre les tentatives (économise)
    print('network config:', wlan.ipconfig('addr4'))

do_connect
# Dépannage : wlan.status donne le code d'échec d'association.
# Après wlan.connect, MicroPython réessaie indéfiniment par défaut.

Expected verification

The console displays network config: ('192.168.x.x', '255.255.255.0', ...): the Pico W has obtained its DHCP lease. You can ping it from your PC (same network). The CYW43 LED may blink during association. Test WPA3 if your router supports it: the cyw43 driver handles it.

Common errors

• 5 GHz network: the CYW43439 is 2.4 GHz only — the connection fails silently or times out. Check the 2.4 GHz band SSID on your router.
• Standard MicroPython firmware (not _picow): network.WLAN returns an error or no interface — re-flash the Pico W build.
• Credentials with special characters improperly escaped in the Python string: test with a simple password first.
• Waiting loop without machine.idle: it works, but you unnecessarily saturate the CPU; idle puts the core in a waiting state between attempts.
• Obstructed antenna: the 14 × 9 mm keep-out area at the edge of the board must not be covered by anything, especially not metal (metal case = Faraday cage, degraded gain — documented in the datasheet).
• Using wlan.status instead of blocking on isconnected: this is the diagnostic tool for association failures (wrong password, AP not found…).