AGB Programming Manual
Rendering Functions
©1999 - 2001 Nintendo of America Inc.
53
D.C.N. AGB-06-0001-002B4
6.2 Bitmap Mode BGs (BG Modes 3-5)
In the bitmap modes, the components of the BG screen are handled in pixel units, and
the contents of VRAM (frame buffer) are displayed as color data for each dot on the
screen.
6.2.1 BG Control
The bitmap BG will be treated as BG2. Therefore, in order to display the
content of the frame buffer on the LCD screen, you need to set the BG2
display flag to ON in the DISPCNT Register. For BG Control the BG2CNT
Register is used.
15 14
13
12 11
10
09 08
07
06 05
04
03 02
01
00
BG2CNT
00Ch
0000h
R/W
Address
Register
Attributes Initial Value
Priority Specification
00: 1st priority
01: 2nd priority
10: 3rd priority
11: 4th priority
0
0
Mosaic
0: Disable
1: Enable
BG2CNT [d06] Mosaic
This controls the ON/OFF of mosaic processing for BG2. When ON, the
settings for the Mosaic Size Register, MOSAIC, are referenced. For
information on Mosaic, see “6.1.2 Mosaic Size”.
BG2CNT [d01-00] Priority Among BGs
Due to the fact that in Bitmap Mode there is only one BG plane(other than
the backdrop plane), there is no priority relationship among BGs, but you
can set up priorities with OBJ. For information on this, see “6.4 Display
Priority of OBJ and BG”.