The photo below shows a part that I am trying to find a specification for. I suspect that it is a microcontroller, and is part of a larger device that is essentially a timer. It clearly bears the National Semiconductor logo.
However, I cannot find this device via searching, and it doesn't seem to fit into the National Semiconductor device naming conventions. Is it plausible that this might be a part custom-made by N.S. for the larger device manufacturer? Is this kind of thing done?