Next two digits - length of the note. It will represent the length exactly as it is shown in MML - 01 is a whole note (C1 for example), 04 is a quarter note (E4), and so on. Since SmileBASIC usually runs at 60 fps, the cap will be 1/60th. I highly doubt you'd want a note that short anyways! If this value is over 60, then this will be a dotted note - 61 is 1., 6F is 15., and so on.