TronDS is a Nintendo 3DS Emulator for Windows that has now ended in development. TronDS was one of three promising 3DS Emulators that all started up around the same time, each making significant inroads into 3DS emulation. Tron3DS made the least inroads into being able to run commercial games out of the 3, but it was good at emulating homebrew.
TronDS did manage to achieve a certain level of emulation, with an ARM9/ARM11 interpreter for the Nintendo 3DS appcore, the core that is dedicated to running user applications. HLE support of the base 3DS operating system to help support userland applications. Basic framebuffer rendering and also featured a ARM11 debugger.
TronDS appears to have now completely ceased development, with the majority of developers and users now focusing on the effortos of the Nintendo 3DS Emulator Citra.