Using Arduino Mega/RAMPS 1.4 with z-probe pin = z-min end-stop pin, if my z-probe triggers high do I need to implement a pull-down resistor on the signal line, or is it pulled down by default?
There is no pull down with avr chips. They can be configured to have pull high in case you trigger against gnd. But for the other way around there is no config option. Is this a mechanical switch? Then all you need is a pullup configured. It does not matter if you get 5v or 0v by default - for that we can invert the signal.
Comments
gnd---- Switch ---- pin ( --- 5v from pullup internally)
so when shorted it is low and when switch is open you have high from pullup.