msm7654 Oki Semiconductor, msm7654 Datasheet - Page 45

• Manufacturer Part Number: msm7654
• Description: Ntsc/pal Digital Video Encoder
• Manufacturer: Oki Semiconductor

OLR, OLG
CLKX2
3-BIT TITLE/GRAPHICS MULTI-FUNCTION
When composite or S-video output is selected, it is possible to impose characters or graphics on
the image by inputting the overlay color RGB signal from the external pins OLR, OLG, and OLB.
Switching between overlay input and image data output is made by using the external pin OLC.
When the RGB signal output is selected, the graphics multi-function is invalid. If the input image
signal does not exist, the blue back display can be output by setting OLC and OLB to "1".
The overlay input timing in the ITU-R BT.656 input mode is different from that in the 8-bit YCbCr
or RGB input mode. The overlay input data in the ITU-R BT.656 input mode becomes valid
immediately after fetching the 4th EAV signal. The overlay input data in the 8-bit YCbCr or RGB
input mode becomes valid after HSYNC_L becomes "L" and Tstart passes and 4 CLKX2 pulses
are input. In the above two cases, the OLC input should be "H" when data becomes valid.
However, "data becomes valid" means that data is internally processed, and does not means that
data can be output.
¡ Semiconductor
DATA
OLC
OLB
SAV(1st)
OLR, OLG,
don't care
HSYNC_L
SAV(2nd)
CLKX2
OLC
OLB
Overlay input timing (8-bit YCbCr or RGB input mode)
YD
SAV(3rd)
Overlay input timing (ITU-R BT.656 input mode)
SAV(4th)
Invalid Data
Invalid Data
Cb0
VALID DATA
Y00
t
STA
Cr0
VALID DATA
Y01
Invalid Data
Cb1
VALID DATA
Y10
Cb0
Invalid Data
Cr1
VALID DATA
Y00
Y11
Cr0
4 CLKX2
Y01
EAV(1st)
Cb1
EAV(2nd)
Valid Data
Y10
don't care
EAV(3rd)
MSM7654
EAV(4th)
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