Hi , you can refer to the library of MusicPlayer.cpp , and you can find that when you run the function (myplayer.playSong(“test.mp3”); ), you can’t do anything but wait.The program run in this function and could be released still the song have stoped. So if you want to run a another function while runing myplay.playSong, you need a interrupt funciton.
By the way,the D1 will flash while the song playing, and digital 8 has connected to D1. So you can also connect a external Led to digital 8,and the external Led will flash too while the song playing .
too prolix…