I have a UNO board. The 5 V reference / 1023 gives +_ 5 Degree between steps of the 1023 divisor since the output of the Temp device is mv = Deg F. 140 mv = 140 deg F. I'm looking for the difference between 130 deg and 140 deg F, which is about the error of the decoded Analog. steps. I could amplify the signal to V = Degrees, or use a 1 volt reference instead of 5 V.. I see the MEGA has 1.1 V ref. Are those two the only options?