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Topic: pin 2 pullup res (Read 611 times) previous topic - next topic

Boffin1

On a freestanding board I saw it is recommended to put a 10 k pullup resistor from pin2 to Vcc to avoid noise.

Can I just set it to an input and take it high to enable the internal pullup?  
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robtillaart

As allways it depends on the context, Why was it recommend on the freestanding board? What was the question/application there? What type of noise?

Rob Tillaart

Nederlandse sectie - http://arduino.cc/forum/index.php/board,77.0.html -
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retrolefty

If the chip has a fairly recent arduino bootloader installed I believe it already sets the internal pull-up on to prevent the bootloader from responding to noise on pin 2 and hanging the chip up waiting for an upload that is not coming. If the chip does not use a bootloader then there is not concern about noise on pin 2.

Lefty


Boffin1

Thanks, it did seem odd when there are pull ups in the chip... I have seen it mentioned several times.
With my mobile phone I can call people and talk to them -  how smart can you get ?

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