Using differential inputs with Arduino IDE

[byoungblood]

I have a project that I originally wrote for an Arduino Uno, before I discovered/understood some of the pitfalls of what I was trying to accomplish.

To summarize, I am making 3 voltage measurements in an old piece of test equipment, and using a micro to do some simple math and then display the result that mimics what the old (not working) analog meter would have given. My complication arose in that the entire measurement circuit in the device floats, and just by the nature of what the device does (tube tester for anyone interested) I was getting odd interactions between a couple of the measurements if they all shared the same ground. I overcame that problem by using a few isolation amplifiers and isolated DC-DC power supplies so that each measurement is taken 100% in isolation from the other. However, these isolation amplifiers have a differential output.

Firstly I just tried tying the negative outputs together, and as I thought, caused the outputs to interact with each other again. I tested again using an LM358 to convert the differential output to single ended, and while this works, adds a lot of parts to the BOM (have to configure it as a differential amplifier).

I was attracted to the STM32 (specifically the STM32F303RE) due the ability to use differential inputs with its ADCs. If I can use this, it would eliminate the need for the extra op amps, resistors, etc..

What I can't find a straight answer to, is it possible to use the differential inputs on the STM32 using the Arduino IDE? And if so, is there a tutorial or could someone walk me though the steps to do it. All I need to do is to be able to do is just call the relevant pins on the STM32 the same way I do with the Uno using AnalogRead. Nothing fancy.