Specifications

60 Issue Date: 2004/11/05 │ CONFIDENTIAL
CL765 │ Camera Application Processor
Datasheet │ Doc. #: CLQP-DS-743
4.13. DISPLAY UNIT
The Display Unit of the CL765 includes alpha-blender and output device interface.
The alpha-blender blends input source images – video image and OSD images –
and compose one image which will be displayed on output devices, LCD’s and TV.
For external visual device interface, the CL765 provides three types of external
visual equipment interfaces: 80-Type LCD, RGB-Type LCD and TV encoder. The
selection of output visual device type is made by programming REG_0x72.
For LCD interface, the CL765 can control two LCD’s – generally one for main-LCD
and the other for sub-LCD. The interface consists of common data and control
signals (18-bit data bus and read/write strobes) and dedicated chip selects for each
LCD. The two LCD’s can be activated exclusively: they share data bus and control
signals, and hence they can not be activated at the same time.
Internal Memory
OSD 2
OSD 1
Video_image
Frame
Background
CCR656/601
Controller
RGB_type
LCD
Controller
80_ type
LCD
Controller
to 80_ type LCD
to RGB_ type LCD
to TV encoder
DISPLAY UNIT
Figure 4-14. Data-flow of Display Unit
Figure 4-16 shows the data-flow of Display Unit. Inputs to the Display Unit are
one video image in 4:2:2-YUV format and two OSD images. The OSD bitmaps are
one of three formats: 8bit-indexed, 4444-αRGB, and 565-RGB. Before alpha-
blending, the source video image is converted into 18-bit RGB format, while OSD
images are converted into 18-bit RGB with 4-bit alpha channel.
The Display Unit has layered architecture: The background is the bottom-layer
and the OSD2 image is the top-layer. The Background and the Frame layer are
only visible when the output visual device is TV. The sequence of making result
image is as follows (For LCD output, STEP1 and STEP2 are skipped):
STEP1 : Background and Frame are multiplexed
STEP2 : The image after STEP1 and video image are multiplexed
STEP3 : The image after STEP2 and OSD1 image are alpha blended
STEP4 : The image after STEP3 and OSD2 image are alpha blended