 can be either <code>INPUT</code>, which is the default, <code>OUTPUT</code>, or <code>INPUT_PULLUP</code> to enable the built-in pull-up resistors for GPIO 0-15. To enable the pull-down resistor for GPIO16, you have to use <code>INPUT_PULLDOWN_16</code>.</p>
   <p>(*) NodeMCU uses a different pin mapping, read more <a href="https://github.com/esp8266/Arduino/blob/master/doc/boards.md#nodemcu-09">here</a>. To address a NodeMCU pin, e.g. pin 5, use D5: for instance: <code>pinMode(D5, OUTPUT);</code></p>
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