Hi,
I'm using smoothie board v1 and I'm trying to connect a proximity sensor by my level converter board to endstop input so I need to configure the pin with a pull-down function. To do it I use the proper "v" symbol after pin assignment in the configuration file. Unfortunately the pull-down selection doesn't work correctly because on the pin there are 4 volts also when the pin is not connected (floating). When try to connect the sensor, Smoothie board recognizes correctly the transition state of the sensor despite 4 volts.
I figured out the problem is the external pull-up resistor (1Kohm before the filter 5K6ohm + 0.1uF) pulled to 5V like showed in the schematic.
I can imagine it's necessary when you need of a pull-up function but you can't use the internal one in the micro because it's pulled to 3,3V. I think a jumper for each endstop input it would be a good thing.
Is it correct?
Thanks
Luca