Specifications

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4.8. SRAM BUFFER SETUP
The CL765 has internally SRAM of 256KByte and the SRAM is classified into its
purpose for use. SRAM Read/Write is performed by 2btye unit. SRAM buffer
areas are Video buffer area, OSD buffer area, and PIP buffer area. Each buffer area
is used only when the relevant functions are used, so it is available for each buffer
to share SRAM area. Following description details each buffer.
1) Video Buffer
Scales down the size of images entered from Camera according to Preview
setup and save. When one frame is completed in Camera, Video buffer
writes data on LCD. The capacity of Video buffer should be set according to
Preview Resolution.
a) Video buffer capacity
If Preview is 128 x 160, Video buffer should be set to 40K byte SRAM area.
b) Data format
Data is saved in Video buffer as YCbCr 4:2:2 format transmitted by
Camera.
2) OSD Buffer
OSD Buffer saves OSD BMP image. The capacity of OSD buffer depends on
OSD Resolution and the maximum capacity is same with that of Video
buffer. In OSD buffer, OSD1 area is set separated from OSD2 area. If OSD
Menu is used, it is available to use OSD1 and OSD2 Buffers.
3) PIP Buffer of CL765
PIP buffer is the SRAM area that saves PIP data. The capacity of PIP buffer
depends on PIP Resolution. In PIP, 4bit is data of 1 pixel and 16bit is data of
4 pixels. Generally, if PIP is set to 128x16, 1K byte is required as a PIP buffer
area.
Following Figure shows the example of SRAM buffer setup. This is the case that
Preview Resolution is set to 128*128, OSD1 and OSD2 buffers are set to 128*16,
and PIP buffer is set to 128*16.
SRAM buffer should be initialized according to Preview, OSD, and PIP setup
when starting Camera Mode. Also, the point of each buffer should be changed in
operating Camera Mode for efficient use of Memory.