This demo uses the Comparator (comp) peripheral to compare the differential voltages between two pins. If the voltage on Pin 30 is higher than Pin 31 (reference voltage) the built in LED will switch off otherwise it will switch on. The demo uses nrf52840-hal but this can be swapped out with an alternative if required.
If using cargo-embed, just run
$ cargo embed --release --target=thumbv7em-none-eabihf