TomSoft's midi converter window with a splash logo included.
TomSoft MegaDrive SDK was created by Tommy Xie, the lead programmer of Dragon Co., and used by Dragon Co. itself during their Mega Drive era.
The package includes a debugger, C++ compiler, MIDI-2-GYM converter and a lot of English documentation on Mega Drive's chip architecture. In addition, it has an audio player ROM with a lot of reconverted Madonna's songs.
The SDK is available for download for free on Tommy Xie's site, yet a few additional mirrors for this SDK have been provided on Pirated Games Central.