In a nutshell, I want to simulate a project with a controlled voltage source. Let's assume it is a simple SPST between 9V and Arduino's VIN.
To my awareness, Proteus is the only software to support ATmega328P simulation. However it doesn't allow me to connect something to VIN (it is internally autopowered instead). Do you guys know of any circuit simulator which may allow me such a (seemingly inordinary) action?