_VCC);</code> at the top of your sketch, and use <code>ESP.getVcc();</code> to actually get the voltage.<br>
    If you use it to read the supply voltage, you can’t connect anything else to the analog pin.</p>
   <h3>Communication</h3>
   <h4>Serial communication</h4>
   <p>To use UART0 (TX = GPIO1, RX = GPIO3), you can use the <code>Serial</code> object, just like on an Arduino: <code>Serial.begin(baud)</code>.</p>
   <p></p>
   <p>To use the alternative pins (TX = GPIO15, RX = GPIO13), use <code>Serial.