unfortuantely docs on the sm83 and sm82 cores are very lacking
its been significantly customized too
the sm83 i/o area is from ff80-ffff, and 256 bytes of ram from fe80-ff7f
its been recently discovered that the dmg cpu is a sharp SM83 (or sm82?) IP core
the gameboy i/o area is from ff00-ff7f (PLUS FFFF) and 127 bytes of ram from ff80-fffe

Package

DMG-CPU B
(C) 1989 Nintendo
JAPAN
9029 W

Die

CE9L80A???