What does the 'Microtonal switch' do? It's one of the options in the MIDI parameter list on the MIDI mapping page. It can be on or off, and a MIDI parameter can be set to control it. (Could it be triggered by a MIDI note? The list gives only continuous controllers and program changes.)
But what is it? It's undocumented.
English manual section 4.2 page 32.
Section 4.2. is not on page 32, and the microtonal switch MIDI parameter is not explained, nor do the words 'microtonal switch' appear in the manual but I take it that it makes the µ button (diapason/scale) available through MIDI. It's not possible to change the .scl / .kbm files through MIDI, so is the intended use for this button to A/B between diapason+temperamet and scale+keymap?
Sorry I had not noticed the change in pagination. The µ button is indeed a switch to select between diapason+temperament and scale+keymap. It can be switched via a MIDI control unit that sends two values, 0 and 127 (like a simple on/off sustain pedal for instance, if you change the MIDI mapping accordingly).
Its use is mostly static I guess, in the construction of a preset.
I figured as much, now that you pointed out the paragraph in the manual. It's just that it's not called 'microtonal switch' in any place else than the midi parameter menu itself, so making a search for the words 'microtonal' or 'switch' in the manual did not lead to the explanation. (In the French manual it's the same.)
But thanks for clearing this out!