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Topic: Pin issue (Read 298 times) previous topic - next topic

lostre86

Hi everyone!

Every pin on my arduino works fine but when i set this

Code: [Select]

pinMode(13, INPUT);
digitalWrite(13, HIGH);


the tiny LED on the board near TX/RX LEDs is dimmed on..

Lucky number 13 ????


dhenry


Nick Gammon

As dhenry is trying to explain, doing that turns on the internal pull-up, which effectively connects the on-board LED to 5V via about a 50K resistor.
http://www.gammon.com.au/electronics

retrolefty

#3
Nov 15, 2012, 09:49 pm Last Edit: Nov 18, 2012, 05:36 pm by retrolefty Reason: 1

As dhenry is trying to explain, doing that turns on the internal pull-up, which effectively connects the on-board LED to 5V via about a 50K resistor.


That shows how efficient modern day leds can be where even 100 micro-amps can generate some light!

Lefty

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