AK8850 Datasheet, PDF (25/99 Pages) Asahi Kasei Microsystems – NTSC Digital Video Decoder

ASAHI KASEI
[AK8850]
7-2. Analog Signal Process Functional Specifications
7-2-1. Input Signal Selector Module
The AK8850 has six (6) input pins. The input signal selector module selects one of the video sources. The Video
sources available are single-pin Composite, 2-pin Y / C and 3-pin Component signals. A Video source to be decoded is
selected by the [INPUT SIGNAL SELECT REGISTER].
The type of Video signal to be decoded is set by the [INPUT VIDEO STANDARD REGISTER].
COMPOSITE SIGNAL INPUT:
This input is digitized by the CLAMP1, PGA1 and ADC1 in the Analog Signal Processing Block Diagram. When decoding
composite video, the ADC2 and ADC3 blocks can be placed in power save mode by programming the [ POWER SAVE
REGISTER].
Y/C SIGNAL (S-VIDEO ) INPUT:
The Y-signal is digitized by the CLAMP1, PGA1 and ADC1 as in the Composite signal input case. The C Signal is
digitized by the CLAMP2, PGA2 and ADC2. The ADC3 block can be placed in Power Save mode by programming the
[ POWER SAVE REGISTER ].
COMPONENT SIGNAL INPUT:
In this case, the Y signal is digitized by the CLAMP1, PGA1 and ADC1 as in the Composite signal input case. The Pb
signal is digitized by the CLAMP2, PGA2 and ADC2, while the Pr signal is digitized by the CLAMP3, PGA3 and ADC3.
Description of the input signal-type set register and input signal select control register:
The input signal type is set by the [ INPUT VIDEO STANDARD REGISTER ] and input signal path is selected by the
[ INPUT SIGNAL SELECT REGISTER ].
[Input Video Standard Register]
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
Reserved
NENT
B/W
SETUP
VS3
VS2
VS1
VS0
Default Value
0
0
0
0
0
0
0
0
[Input Signal Select Register]
bit 7
bit 6
bit 5
Reserved Reserved SYNCIN1
0
0
0
bit 4
bit 3
SYNCIN0 INSEL3
Default Value
1
0
bit 2
INSEL2
0
bit 1
INSEL1
0
bit 0
INSEL0
1
[ VS3 : VS0]-bit and NENT-bit setting are also described.
[Input Video Standard Register] [VS3:VS0]-bit setting
[VS3:VS0]-bit Input Signal source
0000
NTSC
1111
Component 625 (EBU N10)
Note
SETUP-bit :
SETUP-bit
0
1
Setup or No-Setup
No Setup in
With Setup signal in
Note
B/W-bit : for Black and White video signal
B/W-bit
B/W signal or not
0
Color video signal
1
Black and White video Signal
Note
YC separation function turns off
Rev.0
25
2002/01