Hello，I encountered one problem when i was trying to using the audio part on the board Xillinx Ego1. Accroding to the user's reference book, i only need to give a square wave with the frequency of 10000Hz and tie this to the audio part on the board. But i just cannot hear the voice despite doing so. I really want to what do i miss？ Or did i misuse the board? Or did someone encountered the same problem as i did?