I'm trying to perform acquisition of very small analog signals. I have been using an instrumentation amplifier with a gain of ~500, but I would like to try using the differential gain on the ATmega1280's analog inputs. The user manual has a table (Table 26-4, to be precise) with details on how to set the register ADCSRB for a particular choice of single-ended input or pairs of differential inputs, optionally with gain.
Normally, to perform ADC on the Arduino, I write:
but this is for a single-ended input.
My question is: how do I perform differential amplification and conversion within the Arduino language?