Would this work? I'm pretty sure in theory it should, but I don't see it often or at all. In theory, the voltage divider from 2:1 to 1:2 should give 3.3v at one end and 1.6v at the other end of the pot, giving the ADC a wide range to work with. And if the button is pressed, the R1+RV will act as a max 20k pullup, so the line would be down to 0v, which the ADC can be coded to recognize as a unique event, allowing both a button and a pot to exist on the same input pin, allowing the ADC to serve both purposes.

An input pin is saved, without any significant code changes, as the adc is already being polled for the pot.

![schematic](https://i.stack.imgur.com/WMopd.png)

[simulate this circuit](/plugins/schematics?image=http%3a%2f%2fi.stack.imgur.com%2fWMopd.png) – Schematic created using [CircuitLab](https://www.circuitlab.com/)

Would this work, and if so, as a curiosity, why isn't this more popular.