analogReference(INTERNAL) ArduinoMEGA

Forum 2005-2010 (read only) Hardware Interfacing
1

Hi,
I've tryng to use may Arduino MEGA with temperature detector LM35 in range 2°C-100°C. In this situations, the best setting of analog conversion is 1,1V for AREF pin.
This selection in Arduino Duemilanove is performed by analogReference(INTERNAL), but the same function in Arduino MEGA return 2,5V in AREF.

How to obtain 1.1V in MEGA breadbord?
From data sheet:
The reference voltage for the ADC (V ) indicates the conversion range for the ADC. Single
REF
ended channels that exceed V will result in codes close to 0x3FF. V can be selected as
REF REF
either AVCC, internal 1.1V reference, internal 2.56V reference or external AREF pin.

Thanks for your Help.

2

Use analogReference(EXTERNAL) and feed the AREF pin from a voltage divider ?. You could get 1 V from 5V with a 1K and a 4K resistor.