Overactive interrupt triggering using internal pullups

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octavio
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Re: Overactive interrupt triggering using internal pullups

Post by octavio » Mon Sep 18, 2017 10:55 pm

Problem solved,it was electrical noise (problably caused by the serial line).There was a 4cm thin wire betwen the capacitor and the pin,this wire was a enought good antenna to make the chip (an me too) crazy. I solved the problem adding a 3k resistor in series with the pin and as close as possible to the mcu,the pin capacitance and the resitor makes a low band pass filter that cancels the high frecuency noise.
Last edited by octavio on Tue Sep 19, 2017 12:10 am, edited 1 time in total.

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Pito
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Re: Overactive interrupt triggering using internal pullups

Post by Pito » Mon Sep 18, 2017 11:01 pm

So it means your 10uF capacitor did not work as the capacitor at higher frequencies. Most probably you have not used a 10uF ceramic multilayer smd one :)
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octavio
Posts: 42
Joined: Sat Apr 15, 2017 6:41 pm
Location: barcelona
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Re: Overactive interrupt triggering using internal pullups

Post by octavio » Tue Sep 19, 2017 12:08 am

It was a multilayer ceramic capacitor,but there was a 4cm wire betwen the capacitor and the port pin and another 4cm betwen the capacitor and the board gnd.It seems that this wire has a good radiofrecuency coupling with the serial line.

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