Hey all, It might be clear to some of you, but why is the LED13 driven by an OpAmp? In all examples, a LED is simply added with a resistor, but the official Arduino schematics show it with an OpAmp. I've read some guesses: "using left over port on OpAmp", "power drainage"... but that doesn't help …

Why is the LED (13) driven by an OpAmp?

MarkT April 2, 2014, 5:20pm 3

In particular it keeps the pin high enough impedance to work with
external pull-ups and pull-downs.

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