AMD Geode SC1201 - Manual (Page 326)

326 AMD Geode™ SC1200/SC1201 Processor Data Book
Video Processor Module 32579B
Graphics Window
The graphics window is defined in the GX1 module’s dis-
play controller and is always the full screen resolution.
Video Window
The video window tells the Mixer/Blender where the video
window is and its size. If Direct Video mode is enabled (see
Section 7.2.1.1 "Direct Video Mode" on page 316), the
video window must be defined as full screen (720x480 for
NTSC, 720x576 for PAL). Vertical scaling is not allowed.
Horizontal scaling is allowed. If the video source is from the
GX1 module’s video frame buffer (which includes Capture
Video mode, see Section 7.2.1.3 "Capture Video Mode" on
page 316) then the video data can be scaled both horizon-
tally and vertically. The video data size, scaled or unscaled,
must equal the video window size. The Video X Position
(horizontal) and Video Y Position (vertical) registers
(F4BAR0+Memory Offset 08h and 0Ch) define the video
window.
Cursor Window
The cursor window can be managed two ways: with the
GX1 module’s hardware cursor or a software cursor. When
using the hardware cursor, the displayed colors of the hard-
ware cursor must be the cursor color keys (see Section
5.5.3 “Hardware Cursor” in the AMD Geode™ GX1 Pro-
cessor Data Book). When the software cursor is used, the
cursor size and position are not defined using registers.
The cursor size, position, and image are determined
through the use of the cursor color key colors in the graph-
ics frame buffer. When the cursor is described in this man-
ner, the cursor can be of any size and shape.
Alpha Windows
Up to three alpha windows can be defined. They are used
only for blending. They can be of any size up to the graph-
ics window size and they may overlap. To support overlap-
ping of the alpha windows they can be prioritized as to
which one is on top (F4BAR0+Memory Offset 4Ch[20:16]).
The alpha windows are programmed at F4BAR0+Memory
Offset 60h-88h.
Figure 7-11. Graphics/Video Frame with Alpha Windows
Graphics Window (GFX_INS_VIDEO = 0)
Video Window
Alpha Window #3
Cursor
Window
ALPHA1_WIN_PRIORITY = 10
ALPHA2_WIN_PRIORITY = 01
ALPHA3_WIN_PRIORITY = 00
Video X
Video Y
Position
Register
Alpha Window 3
X Position
Alpha
Window 3
Y Position
Register
Register
Al
ph
a W
ind
o
w
#2 Alpha Window #1
Position Register