I tried different search keywords combinations, but I couldn’t find a datasheet, nor a hint of what this IC could be. Maybe someone who’s familiar with it could give me a clue. 
The IC is on a board that was part of the control panel of a home theater. The options were volume up and down, surround 2.1 or 5.1 and mute. The brand was National Star, as far as I can recall. Thanks in advance.
Best Answer
Judging by the ceramic resonator and load capacitors connected to pins 15 and 16, it's almost surely a microcontroller with a custom program in OTP or flash memory. And typically the program memory is read-protected for the security of the manufacturer's firmware.
So more than likely it's not the sort of thing you'll be able to buy from other sources than the original, such as a used board or repair part.