TheAliw1:
What is the function of this capacitor in parallel in #2 and what is the value of the DNP resistor and what does DNP stand for?
It's always a best practice to use capacitors coz they reduce any noise or fluctuations in power line. If you are using a simple push button with Arduino then you can use a resistor of 1 K ohm. Don't know what's DNP.
"Do Not Populate" is used when there are optional components. There will be holes or pads on the board but the normal manufacturing process won't place any component there. You can add that to the board yourself, if it turns out that your application needs it.
The capacitor is used to ensure a consistent reset when the power is first applied. It takes a little while for the capacitor to charge, so it holds the chip in reset state until (hopefully) the power voltage has come up enough for the chip to run properly. Without that, the chip may attempt to start in the first nanosecond that power starts coming up, which may be insufficient voltage for the chip to run properly.
If you are adding a reset button to an already-working Arduino board, use the first schematic.
MorganS:
Without that, the chip may attempt to start in the first nanosecond that power starts coming up, which may be insufficient voltage for the chip to run properly.
Although that functionality is necessarily built into the chip.
If you are adding a reset button to an already-working Arduino board, use the first schematic.
This is what I am going for. Thanks!
I'm still quite interested to what you guys are saying about the capacitor. I understand I don't need it for an external reset button but I'd love to learn more about it so I'm watching your posts