Lcd Display Registers - Nintendo GAME BOY Programming Manual

1.6 LCD Display Registers

NAME ADDRESS
FF40h
LCDC
BIT 7 6 5 4
LCD Controller Operation Stop Flag
0: LCDC Off
1: LCDC On
* In CGB, the liquid crystal protection circuit functions when
the LCDC is turned on. Consequently, a white screen is
displayed for up to 2 frames. In DMG, the LCDC should be
off during vertical blanking periods.
3 2 1 0
BG Code Area Selection Flag
0: 9800h-9BFFh
1: 9C00h-9FFFh
BG Character Data Selection Flag
0: 8800h-97FFh
1: 8000h-8FFFh
Windowing On Flag
0: Off
1: On
Window Code Area Selection Flag
0: 9800h-9BFFh
1: 9C00h-9FFFh
57
Chapter 2: Display Functions
R/W LCD Control Register
CGB Mode: BG display always on
DMG Mode: 0: BG display off
1: BG display on
OBJ On Flag
0: Off
1: On
OBJ Block Composition Selection Flag
0: 8 x 8 dots
1: 8 x 16 dots