This part is a kind of semiconductor called UPD75304B.

Function of this product has 4-BIT SINGLE-CHIP MICROCOMPUTER.

Manufacturers : NEC

Image and pinout :

Some of the text within the PDF file :

DATA SHEET µPD75304B,75306B,75308B 4-BIT SINGLE-CHIP MICROCOMPUTER MOS INTEGRATED CIRCUIT DESCRIPTION The µPD75308B is a 75X Series 4-bit single-chip microcomputer capable of the same data processing as an 8-bit microcomputer. It is a low voltage operation version of the µPD75308 with on-chip LCD controller/driver. Operation at an ultra-low voltage of 2.0 V is possible. An ultra small-sized plastic QFP (12 × 12 mm) is also provided and it is perfect for small-sized set that uses an LCD panel. Functions, etc., are described in detail in the User's Manual. Please be sure to read this manual when carrying out design work. µPD75308 User's Manual: IEM-5016 FEATURES • Ultra-low-voltage operation possible: VDD = 2.0 to 6.0 V • Can be driven by two 1.5 V manganese batteries. • On-c [ ... ]

UPD75304B PDF Datasheet Download