Universal IO

The board have 3 universal I/O. Scheme of this:

You can use it in some scenario:

Analog input

Maximum input voltage: Vmax = 3.3V*(R16+R17)/R17. Please calculation R16/R17 for you voltage range.

Open-drain output

5V tolerance digital I/O

Termistor connect

AN1 also have addition resistor R8, it avail connect NTC-termistor:

The second termistor pin connect to ground.