This guide will get you up and running with simulating the analog OPAMP module in AVR DB family devices using the Mindi simulation tool. For a larger overview, see "Getting Started with Analog Signal Conditioning (OPAMP)".
The differential amplifier op amp configuration outputs the amplified difference between two signals. The amplification can be configured by setting the feedback divider.
Download and open the Mindi schematic here
Press the play button to simulate with an example stimulus source.
The amplification of the differential amplifier can be adjusted to any of 8 levels from 0.06 to 15 by changing the MUXWIP value in the control register. The Mindi schematic contains a table detailing the levels of gain and their associated register and resistor values.
Once the desired result has been verified with Mindi simulation, the corrected values should be moved back into MCC/Start by copying resistor configurations across to the composer of your preference.
You can download and install the Mindi simulation tool, or use another SPICE simulator of your own preference. For use with different simulators, a plain spice model can be found in "Opamp_AVR_DB.txt" to replace the mindi-optimized ".lb"