add wifi

docs/en/tutorials/c3/get_started_with_arduino_c3.rst

@@ -25,6 +25,56 @@ Upload Code
   * Press **Button Reset**
   * Release **Button 9** When you hear the prompt tone on usb reconnection
 
+WIFI
+-----------------
+You need set WIFI Tx Power to 8.5dBm to use WIFI.
+
+Use **WiFi.setTxPower(WIFI_POWER_8_5dBm)** after 
+**WiFi.begin()** or **WiFi.softAP()**
+
+.. code-block:: arduino
+
+  WiFi.begin(ssid, password);
+  WiFi.setTxPower(WIFI_POWER_8_5dBm);
+
+.. code-block:: arduino
+
+  WiFi.softAP(ssid, password);
+  WiFi.setTxPower(WIFI_POWER_8_5dBm);
+
+**simple test:**
+
+.. code-block:: arduino
+
+  #include <WiFi.h>
+
+  const char* ssid = "yourssid";
+  const char* password = "yourpasswd";
+  void setup() {
+    Serial.begin(115200);
+    delay(1000);
+
+    Serial.println("Connecting...");
+    WiFi.mode(WIFI_STA);
+    WiFi.disconnect();
+    
+    WiFi.begin(ssid, password);
+
+    WiFi.setTxPower(WIFI_POWER_8_5dBm);
+
+    while (WiFi.status() != WL_CONNECTED){
+      Serial.print(".");
+      delay(500);
+    }
+
+    Serial.println("Connected");
+    Serial.print("IP address: ");
+    Serial.println(WiFi.localIP());
+  }
+
+  void loop() {
+  } 
+
 Documentation
 -------------------------
   * `ESP32-S2 and ESP32-C3 Support <https://github.com/espressif/arduino-esp32#esp32-s2-and-esp32-c3-support>`_