AK8851 Datasheet, PDF (39/80 Pages) Asahi Kasei Microsystems – NTSC/PAL/SECAM Digital Video Decoder

ASAHI KASEI
[AK8851]
23. VBI Slice Function
The AK8851 has a function to slice VBI data. The sliced data is output in 601 digital format.
The VBI slice function is handled in the Luminance signal-processing path. In the VBI function, the 601-output codes for
Cb/Cr values for the selected Lines are equal to corresponding Luminance signals.
Slice level and the output code are set via register. Lines to be sliced include all Lines within the VBLANK interval that are
specified by the [Output Format Register].
* [mV]
N T S C /PA L
714/700
601 Code
235
100% W hite
357/350
127
180/175
63
Setting value “!” on [SLLVL1]/[SLLVL2]
Setting value “0” on [SLLVL1[/[SLLVL2]
*target value [mV] is approximately voltage
L L •• L L
•••
Cb / Y ••• Cr / Y
H H •• H H
Cb / Y ••• Cr / Y
L
•••
L
The Value which Is set on
[Low Data Set Register]
H
The Value
[High Data
which is set on
Set Register]
Bit allocation of [Output Format Register] is shown below.
Sub Address 0x02
bit 7
bit 6
VBIDEC1
VBIDEC0
0
0
bit 5
SLLVL
0
bit 4
bit 3
TRSVSEL 601LIMIT
Default Value
0
0
bit 2
VBIL2
0
Default Value : 0x00
bit 1
bit 0
VBIL1
VBIL0
0
0
[VBIDEC1:VBIDEC0]-bit:
* This is a control bit to set tasks during the Vertical Blanking interval which is specified by [VBIL2 :VBIL0]-bit.
[VBIDEC1:VBIDEC0]-bit
VBI data output
Note
00
Black Level Output
Y = 0x10
Cb/Cr = 0x80
Y = sampling data is converted to
01
Black and White mode
Rec.601 Level
Cb/Cr = 0x80
10
Sliced data is output during VBI Interval
Y/Cb/Cr = Sliced level which set at the
Slicer Register
11
Reserved
Reserved
MS0244-E-03
39
Confidential
2005 / 07