I'm currently working on a control system for a hot water solar panel and as part of the system I want to have the current solar irradiation displayed on an LCD.
I have a 2 wire calibrated solar cell (pyranometer) which gives a linear voltage output to a linear solar irradiation input, measured in W/m2. The voltage is very low, 0.158 V at 1000 W/m2 solar irradiation. So to get better resolution I use the internal 1.1 voltage reference.
But if I understand it correct, when I set the internal reference to 1.1 V, I do so for all pins. This is not so great, since I would like to use other temperature sensors and motor controls (pump) with the same board which require a different voltage reference.
Is it possible to set the 1.1V reference only to the pin which the pyranometer connects to and have 5V for the rest of the pins?