0000 7FFF Cartridge
8000 9FFF Video RAM
A000 BFFF External RAM (Cartridge)
C000 DFFF Work RAM
E000 FCFF Copy of the work RAM
FE00 FE9F OAM (Sprite Attribute Table)
FEA0 FEFF Unused
FF00 FF7F Hardware IO 
FF80 FFFE High RAM
FFFF FFFF Interrupt switch

Hardware IO:
F00 Buttons -> 00000000 / state inverted
               XX01v^<>
                 10SSBA (start select)

Flags:
ZSHC????

Zero
Substraction
Half Carry
Carry