Samsung S3C2451X User Manual page 563

S3C2451X RISC MICROPROCESSOR
BLENDING DIAGRAM/DETAILS
LCD controller could blend 2-Layer for the only one pixel at the same time. The Blending factor, alpha value is
controlled by ALPHA0_R/G/B and ALPHA1_R/G/B fields in Window 1 Alpha Value register or DATA[27:24] in
frame buffer, which are implemented for each window layer and color(R,G,B). As a special feature, between two
windows have two kinds of alpha blending value. One is ALPHA0_R/G/B(AEN=0) and the other is
ALPHA1_R/G/B(AEN=1).
BLD_PIX = 0
(WINCON1[6])
BLD_PIX = 1
@WINCON1[6]
COLOR-KEY FUNCTION
The LCD controller can support color-key function for the various effect of image mapping. Color image of OSD
layer, which is specified by COLOR-KEY register, will be substituted by background image for special
functionality, as cursor image or pre-view image of the camera.
The register value to ColorKey reg must be set in 24bit RGB format.
DIRCON (in Win1 Color Key 0 register) bit selects the window to be compared with COLVAL (in Win1 Color Key 1
Register). If this bit is set to '0', the comparison window is window1 (foreground window).
COMPKEY (in Win1 Color Key 0 register) value decides whether to compare COLVAL and selected window color.
In other words, the comparator only compares COLVAL and selected window color bits where the corresponding
bit in COMPKEY is '0'.
Table 22-4. Alpha Value Selection Table for Blending
ALPHA_SEL = 0
@WINCON1[1]
ALPHA_SEL = 1
@WINCON1[1]
ALPHA_SEL = 0
@WINCON1[1]
ALPHA_SEL = 1
@WINCON1[1]
Preliminary product information describe products that are in development,
for which full characterization data and associated errata are not yet available.
Specifications and information herein are subject to change without notice.
KEYBLEND = 0
@W1KEYCON0[26]
KEYBLEND = 1
@W1KEYCON0[26]
DATA[27:24] in frame buffer for 28bpp mode
ALPHA0_R/G/B
ALPHA1_R/G/B
AEN = 0
AEN = 1
Non-Key area
Key area
LCD CONTROLLER
ALPHA0_R/G/B
ALPHA1_R/G/B
ALPHA0_R/G/B
ALPHA1_R/G/B
22-23