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→Input Reading
>>> p = Pin( 15, Pin.IN )
>>> p = Pin( 15, Pin.IN )
>>> p.value()
>>> p.value()
0 <--- Pin tied to GND
0 <--- Pin tied to GND
>>> p.value()
>>> p.value()
1 <--- Pin tied to 3.3V
1 <--- Pin tied to 3.3V
</syntaxhighlight>
</syntaxhighlight>
When the Pin is neither tied to GND, neither to 3.3V, then the pin voltage is said "floating".
The logical state of a floating pin is unpredictable, it may be High, it may be Low... we don't know.
To avoids that issue, the best is to use a pull-up resistor. Many microcontroler have internal pull-up resistor (it just needs to be activated).
== Analog Reading ==
== Analog Reading ==