#include void display_turnOffStatusLed(void); void display_turnOnStatusLed(void); void display_setVolume(int level); void display_setModeToMinimum(void); void display_setModeToMaximum(void); void display_setModeToAverage(void); bool display_isError(void); void display_powerDown(void); void display_updateData(int data, void(*updateCompleteCallback)(void)); /* The entry is returned (up to `length` bytes) in the provided `entry` buffer. */ void display_getKeyboardEntry(char * entry, int length);