On page 2 of this schematic, section A5, a reset button can be seen. In series with it is a 39 ohm resistor and a 330 ohm resistor:
https://www.arduino.cc/en/uploads/Main/Arduino-Zero-schematic.pdfI know the 330 ohm resistor is for limiting the current just in case the pin is switched to an output. But what purpose does the 39 ohm resistor and capacitor serve?
I can read well enough, so I know the capacitor is for noise reduction. But why would one need to reduce noise on a reset switch? And how does the 39 ohm resistor come into play? It would slow down the rate at which the capacitor discharges when you press the switch I suppose, but why is that necessary?
I do have a theory about what it's there for. I know that on the original Arduino they had added a diode to the reset circuit because the voltage was spiking negative when the reset button was pressed and this would cause the microcontroller to lock up. But in that circuit there was a capacitor in series with the reset pin, so it's not quite the same here. But could the 39 ohm resistor be to prevent a negative spike when the capacitor is discharged through the reset switch?