I am pretty new to the analog microcontrollers and I was hoping someone might be able to answer a ouple of questions. I read in the data sheet that ADC1 can be used as 4 differential inputs, but only has gains of 1,2,4, and 8. In my application I am using a resistive bridge transducer that outputs 2mV/V. I want to use a 5V excitation voltage which gives me a max range of 0-10mV. How can I use an external voltage source to provide 5V to the ADC and bridge? The second question is: if I want a 0-10mV, can I tie vref+ and vref- to ground to get a unipolar input?