If you truly need free and legal simulation with Arduino, consider:
The combination of and Arduino IDE 1.8 provides an essential virtual laboratory for engineering students and hobbyists to design, test, and debug electronic systems without physical hardware. By integrating these two platforms, users can bridge the gap between firmware development and circuit simulation, ensuring that designs work perfectly before moving to a physical breadboard. The Power of Proteus 8.9 SP2 Professional proteus 8.9 sp2 professional with arduino 1.8 free
To run Proteus 8.9 SP2 smoothly alongside Arduino 1.8, your PC should meet these specs: If you truly need free and legal simulation
: In Proteus, double-click the Arduino board in your schematic. proteus 8.9 sp2 professional with arduino 1.8 free
The integration of Proteus 8.9 SP2 Professional Arduino 1.8 IDE