🛠 Se connecter au WiFi et lire l'heure NTP (WiFiS3)

Objectives

Leverage the board's second chip: the embedded ESP32-S3 acts as a WiFi (2.4 GHz only) and Bluetooth Low Energy modem, controlled from the RA4M1 via the official WiFiS3 library. You will connect to a WPA2 network, retrieve the time from an NTP server, and understand the "two brains" model: the RA4M1 runs your sketch, while the ESP32-S3 runs its own WiFi stack and communicates with the RA4M1 over UART.

Hardware

• 1 Arduino UNO R4 WiFi + USB-C cable
• A 2.4 GHz WiFi access point (not 5 GHz: the ESP32-S3 does not support it)
• Outgoing Internet access (NTP = UDP 123) for the clock step.

Full Code

#include <WiFiS3.h>

const char* SSID = "votre-reseau";
const char* PASS = "votre-cle";

void setup {
  Serial.begin(115200);
  while (!Serial && millis < 5000) { }  // laisse le temps d'ouvrir le Moniteur

  Serial.print(F("Connexion a ")); Serial.println(SSID);
  WiFi.setTimeout(20000);          // patience : 20 s max
  int status = WiFi.begin(SSID, PASS);
  if (status != WL_CONNECTED) {
    Serial.print(F("Echec, code ")); Serial.println(status);
    while (true) { }               // en prod : réessayer, pas boucler
  }
  Serial.print(F("IP = ")); Serial.println(WiFi.localIP);

  unsigned long epoch = WiFi.getTime;   // requête NTP via l'ESP32-S3
  Serial.print(F("Epoch NTP = ")); Serial.println(epoch);
}

void loop {
  if (WiFi.status != WL_CONNECTED) {
    Serial.println(F("WiFi perdu, reconnexion..."));
    WiFi.disconnect;
    WiFi.begin(SSID, PASS);
  }
  delay(1000);
}

Expected Verification

The Monitor displays a local IP address (192.168.x.x) followed by a consistent Unix timestamp (≈ 1.7–1.8 billion seconds). Unplug the WiFi router: WiFi.status goes offline and the reconnection loop takes over.

Common Errors

• 5 GHz network: connection fails systematically — the ESP32-S3 is strictly 2.4 GHz.
• Special characters or accents in the password entered in the sketch: escaping and encoding can cause issues; test with a simple key first.
• Calling WiFi.begin without a timeout followed by code that proceeds too quickly: use WiFi.setTimeout and check the return code.
• Having reflashed the ESP32-S3 with custom firmware: the WiFiS3 modem is no longer present — you must reflash the original firmware (official tutorial "custom firmware ESP32-S3", see advanced tutorial).
• Confusing the two chips in the logs: a status that never changes often signals a problem with the RA4M1↔ESP32-S3 UART link, not your network.