The software is available for Windows or Linux and the AVR/Arduino emulation is built in. It allows you to simulate analog circuits, LCDs, stepper and servo motors and can include programmable PIC or AVR (including Arduino) processors in your simulation. I recently found an open source project called Simulide that has a few issues but does a credible job of mixed simulation. However, both of those don’t do a lot for you if a microcontroller is a major part of your design. I’ve done quite a few posts on LTSpice and I’m also a big fan of the Falstad simulator in the browser. Sure, there’s no substitute for actually building a circuit but it sure is handy if you can fix a lot of easy problems before you start soldering and making PCBs. I’ve always appreciated simulation tools.
