Rendering Functions; Character Mode Bg (Bg Modes 0-2); Control; Table 8 - Background Mode Registers - Nintendo GAME BOY ADVANCE Programming Manual

May 25, 2005
6

Rendering Functions

The Game Boy Advance CPU has 96 KB of built-in VRAM.
Its rendering functions include BG and OBJ display capability. The method used for BG rendering varies
with the BG mode, as described below.
6.1

Character Mode BG (BG Modes 0-2)

In character mode, the components of the BG screen are basic characters of 8 x 8 pixels.
6.1.1 BG Control
There are 4 BG control registers, corresponding to the maximum number of BG screens (registers
BG0CNT, BG1CNT, BG2CNT, and BG3CNT).
Registers BG0CNT and BG1CNT are exclusively for text BG control, while BG2CNT and BG3CNT also
support BG rotation and scaling control.
The registers used by the BG modes are as follows.

Table 8 - Background Mode Registers

BG Mode
0
1
2
© 1999-2005 NINTENDO
BG Control Register
BG0CNT BG1CNT
BG0 BG1
(text) (text)
BG0 BG1
(text) (text)
BG2CNT BG3CNT
BG2
(text)
BG2
(rotation/scaling)
BG2
(rotation/scaling) (rotation/scaling)
AGB-06-0001-002-B13
Released: May 27, 2005
25
BG3
(text)
BG3