AK8856VN Datasheet, PDF (33/98 Pages) Asahi Kasei Microsystems – NTSC/PAL Video Decoder

ASAHI KASEI
[AK8856VN]
Closed Caption / Closed Caption Extended Data / VBID (CGMS) / WSS
Closed Caption data, Closed Caption Extended data, VBID (CGMS) and WSS signals that are super-imposed
during the VBI interval are decoded in the AK8856. The decoded data is written into a register. When the
request bits [bit3 : bit 0] of the Request VBI Info Register ( W ) [ Sub Address 0x0A] are set, the AK8856
acknowledges that a decode request of the data has been made, and it is placed into a data wait condition. After
data is detected and decoded, the host is notified, using [bit7 : bit 5] of the Status Register (R/W) [Sub
Address 0x10] that decoding has been completed.
The results are written into the Closed Caption 1 Register ( R ) [ Sub Address 0x12 ] / Closed Caption 2
Register ( R ) [ Sub Address 0x13 ], Extended Data 1 Register ( R ) [ Sub Address 0x14 ] / Extended Data
2 Register ( R ) [ Sub Address 0x15 ], VBID / WSS1 Register ( R ) [ Sub Address 0x16 ] / VBID / WSS2
Register ( R ) [ Sub Address 0x17 ] respectively.
The data are super-imposed on the respective line:
CRCC code of VBID data (CGMS-A) is decoded and the result is stored in the register.
Signal
Line
Note
Closed Caption
NTSC : Line-21
525-Line
Closed Caption Extended
NTSC : Line-284
525-Line
VBID
NTSC : Line-20/283
525-Line
WSS
PAL : Line-23
625-Line
Configuration of Request VBI INFO Register:
Sub Address 0x0A
bit 7
bit 6
Reserved
Reserved
0
0
bit 5
Reserved
0
bit 4
bit 3
Reserved
Reserved
Default Value
0
0
bit 2
VBWSRQ
0
Default Value: 0x00
bit 1
bit 0
EXTRQ
CCRQ
0
0
Configuration of Status Register is as follows
Sub Address 0x10
bit 7
bit 6
VBWSSDET EXTDET
bit 5
CCDET
bit 4
AGCSTS
bit 3
VLOCKSTS
bit 2
PKWHITE
bit 1
COLKILST
bit 0
NSIG
MS0522-E-00
33
2006/Dec