analogReadResolution()

Set resolution of ADC used in analogRead(). This means that it will map input voltages between 0 and Vcc (about 3 V) into integer values between 0 and 2resolution-1. analogReadResolution(resolution) resolution the number bits to use: 1–16 None Most popular resolutions are:
resolution in bitsDescriptionrange of values returned by analogRead()
10 (default)Arduino Uno compatibility mode0–1023
12maximum possible in Z-Uno0–4095
8can save energy in battery devices (uses special mode of Z-Wave MCU to make ADC faster)0–255