This part is a kind of semiconductor called HD6303.

Function of this product has User Manual.

Manufacturers : Hitachi Semiconductor

Image and pinout :

Some of the text within the PDF file :

HD6301 / HD6303 User Manual Hitachi Semiconductor http://www.jaapsch.net/psion/pdffiles/hd6301-3_handbook.pdf [ ... ]

HD6303 PDF Datasheet Download