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AMD Geode™ SC2200 Processor Data Book 333
Video Processor Module
32580B
Mixing/Blending Operation
Table 7-2 on page 333 shows the truth table used to create the flow diagram, Figure 7-12 on page 334, that the Mixer/
Blender logic uses to determine each pixels disposition.
Table 7-2. Truth Table for Alpha Blending
COLOR_
CHROMA_SEL
1
1. COLOR_CHROMA_SEL: F4BAR0+Memory Offset 04h[20].
Windows Configuration
2
2. GFX_INS_VIDEO: F4BAR0+Memory Offset 4Ch[8].
ALPHAx_COLOR_REG_EN: F4BAR0+Memory Offsets 68h[24], 78h[24], and 88h[24].
Graphics
Data Match
Cursor
Color Key
Graphics
Data Match
Normal
Color Key
Video Data
Match
Normal
Color Key Mixer Output
x x x Yes x x Cursor Color
x Not in Video
Window
x No x x Graphics Data
Graphics Color
Key
(COLOR_
CHROMA_SEL
= 0)
Not in an Alpha
Window
GFX_INS_VIDEO = 0 No Yes x Video Data
No No x Graphics Data
GFX_INS_VIDEO = 1 No x x Video Data
Inside Alpha
Window x
ALPHAx_COLOR_REG_EN = 1 No Yes x Color from
Color Register
ALPHAx_COLOR_REG_EN = 0 No Yes x Video Data
x No No x Alpha-blended
Data
Video Chroma
Key
(COLOR_
CHROMA_SEL
= 1)
Not in an Alpha
Window
GFX_INS_VIDEO = 0 No x Yes Graphics Data
No x No Video Data
GFX_INS_VIDEO = 1 No x x Graphics Data
Inside Alpha
Window x
ALPHAx_COLOR_REG_EN = 1 No x Yes Color from
Color Register
ALPHAx_COLOR_REG_EN = 0 No x Yes Graphics Data
x No x No Alpha-blended
Data