What are the BT_FUNC2 and BT_FUNC5 pins used for?

Answer

When BT is awake and active, BT_WU (BT_FUNC2) is high (from host to module). This is an active high signal. The host puts the BT section to sleep by de-asserting (logic low level) the BT_WU signal (input to the module). The module then drives HOST_WU (BT_FUNC5) low to acknowledge to the host that it is has been put into sleep mode.