Yes but only if you have a common ground. That's because the terminal of an external power supply could be at very different potential (relative to the earth) and break the FOX board.
Please explain better what you want to do. Sergio cchechio wrote: > > > I have read http://www.acmesystems.it/?id=17, > <http://www.acmesystems.it/?id=17,> the title > > "Connect an external switch". > > Can I connect the external switch with an external 3.3 volts ? > > If yes , how ?
