Flowcharts - Nintendo GAME BOY Programming Manual

Game Boy Programming Manual

6.3 Flowcharts

1) Branched Processing for CGB and DMG/MGB/MGL
CGB support code (0x80) written to ROM
01h (DMG)
FFh (MGB/MGL)
(DMG/MGB/MGL)
data area (address 0x143)
Start
Unit Discrimination:
Value of register A is
read
Initialization
Color Palette Transfer (rewrite)
OAM Transfer
BG CHR Code Transfer
CGB?
CGB Flag Check
=0
LCDC ON
Color display in CGB
Monochrome display in DMG/MGB/MGL
LCDC OFF
or blanking
134
Supplemental processing
for CGB support
0x11 CGB
CGB flag
(LCD Display RAM Bank 0)
= 1 (CGB)
LCD display RAM switched to bank 1,
BG attributes transferred.
1