Nintendo 1504166 - Game Boy Advance SP Edition Console Programming Manual page 30

AGB Programming Manual
DISPCNT [d07] Forced Blank
Setting this bit causes the CPU to forcibly halt operation of the image
processing circuit, allowing access to VRAM, color palette RAM, OAM, and
the internal registers. The LCD screen displays white during a forced
blank. However, the internal HV synchronous counter continues to operate
even during a forced blank. When the internal HV synchronous counter
cancels a forced blank during a display period, the display begins from the
beginning, following the display of three vertical lines.
DISPCNT [d06] OBJ Character VRAM Mapping Format
Specifies the VRAM mapping format for an OBJ character.
A setting of 0 causes the OBJ character to be handled in memory mapped
2-dimensional. A setting of 1 causes the OBJ character to be handled in
memory mapped 1-dimensional.
For information on OBJ character VRAM mapping formats, see section
6.3.2, Character Data Mapping.
DISPCNT [d05] H-Blank Interval OBJ Processing Flag
A setting of 0 executes OBJ Render Processing with all H-Line
intervals(including H-Blank intervals).
A setting of 1 executes OBJ Render Processing with the display intervals
only and not for H-Blank intervals. Thus, when the user accesses OAM or
OBJ VRAM during an H-Blank interval, this bit needs to be set. However,
also in this situation, maximum OBJ display performance cannot be
obtained.
DISPCNT [d04] Display Frame Selection
When rendering in bitmap format in a mode in which there are 2 frame
buffers (BG modes 4 and 5), this bit allows selection of one of the frame
buffers for rendering. A setting of 0 selects the contents of frame buffer 0
for rendering; a setting of 1 selects the contents of frame buffer 1 for
rendering.
DISPCNT [d03] (CGB Mode)
AGB is equipped with 2 CPUs. In AGB mode, a 32-bit RISC CPU starts,
and in CGB mode, an 8-bit CISC CPU starts.
controlled by the system, it cannot be accessed by the user.
DISPCNT [d02-00] BG Mode
Selects the BG mode from a range of 0-5.
For more information on BG modes, see the following section.
©1999 - 2001 Nintendo of America Inc.
Because this bit is
30
Image System
D.C.N. AGB-06-0001-002B4