I am wondering how do you draw user IO (not used anywhere else) in the schematic?
I have a 20-pin header for user IO. Some of the pins in that header are not internally connected to any other part of the design. If I keep that pin unconnected, then there are ERC error. I had to place the no connect flag (X) to get rid of the ERC.
Is that the right thing to do?
Personally, I always break out unused header pins to at least a resistor to power or ground. Then I leave it unconnected. My main goal is to always have a place to easily solder wires to when things go wrong.
Otherwise, if you’re really not going to use it, I think marking it unconnected/NC is the way to go.
Yes, if you’re deliberately leaving any pin unconnected using the “Place not-connected flag” tool and putting a blue cross on the pin is the correct way to tell the ERC that this isn’t a mistake. This is true for any pin, IC, connector etc. It’s saved me a few times from forgetting to hook things up that I’d intended to go back to then forgotten about.
I do the same, I place the “no connect flag” there. I see no downside of doing so, why would you not want to place one?