Arduino Pro Mini - Advanced I/O Function
analogReference() Function Configures the reference voltage used for analog input (i.e. the value used as the top of the input range). The options are − DEFAULT − The default analog reference of 5 volts (on 5V Arduino boards) or 3.3 volts (on 3.3V Arduino boards) INTERNAL − An built-in reference, equal to 1.1 volts on the ATmega168 or ATmega328 and 2.56 volts on the ATmega8 (not available on the Arduino Mega) INTERNAL1V1 − A built-in 1.1V reference (Arduino Mega only) INTERNAL2V56 − A built-in 2.56V reference (Arduino Mega only) EXTERNAL − The voltage applied to the AREF pin (0 to 5V only) is used as the reference analogReference() Function Syntax analogReference (type); type − can use any type of the follow (DEFAULT, INTERNAL, INTERNAL1V1, INTERNAL2V56, EXTERNAL) Do not use anything less than 0V or more than 5V for external reference voltage on the AREF pin. If you are using an external reference on the AREF pin, you must s...