The code is here for nostalgic reasons. The Monster was based on the AT90S2313. The two MIDI-Outputs with one UART were faked using two NAND-Gates, which allowed controlling of the START/STOPP-byte to the appropriate MIDI-OUT.
I don't even know why I have written this in assembler. I guess this happened under the impression that it hat to be timing solid. Hm.
What I really don't know anymore is the type of the really nice display.