rootnote audio loop player

[yall]

2nd question of the day :)
I have an audio loop player. I would like to be able to recover the values ​​of the RootNote button. rootnote ranges from 0 to 127.
I would like to be able to change 0, 127 by A # B C C # ...... thing not very complicated with a normal button but, how to recover this data knowing that one cannot create custom callback on the modules?
this will display the note of the sample we have just imported