AK8850 Datasheet, PDF (58/99 Pages) Asahi Kasei Microsystems – NTSC Digital Video Decoder

ASAHI KASEI
[AK8850]
A procedure to read out each data is described here.
Start
[Request VBI Info Register]
xxRQ-bit = 1
(Decode Request)
[Status 2 Regsiter] Read
(Check decode status bit)
If Closed Caption, then CCRQ-bit
If VBID, then VBIDRQ-bit
If WSS, then WSSRQ-bit
If xx-bit = 1
Yes
Read Data Register
No
If Closed Caption, then CC-bit
If VBID, then VBID-bit
If WSS, then WSS-bit
If Closed Caption, then[Closed Caption 1 2 Register]
If VBID, then [VBID 1 2 Register]
If WSS, then [VBID 1 Register][WSS 2 & ASPECT Data Register]
READ OPERATION OF CLOSED CAPTION DATA :
To read closed-caption data, write “1” to the CCRQ-bit. The AK8850 will enter a wait state for the Closed Caption data
decoding. Upon receipt of the data, it is decoded and when decoding is completed, ”1” is sent back to CC-bit of the
[ STATUS 2 REGISTER ].
The CC-bit is usually at “1” right after a reset ( it becomes “0” by writing “1” at CCRQ-bit ).
The decoded data is written into the [ CLOSED CAPTION 1.2 REGISTER ] as shown. Data in the [ CLOSED CAPTION
1.2 REGISTER ] is remains in this register until it is over-written.
* [ CLOSED CAPTION 1 REGISTER ]
bit 7
bit 6
bit 5
CC7
CC6
CC5
bit 4
CC4
bit 3
CC3
bit 2
CC2
bit 1
CC1
bit 0
CC0
* [ CLOSED CAPTION 2 REGISTER ]
bit 7
bit 6
bit 5
CC15
CC14
CC13
bit 4
CC12
bit 3
CC11
bit 2
CC10
bit 1
CC9
bit 0
CC8
READ OPERATION OF CLOSED CAPTION EXTENDED DATA :
Write “1” at EXTRQ-bit, which places the AK8850 into a wait state while Extended Data decoding occurs. The received
data is decoded and after the decoding is completed,”1” is sent back to EXT-bit of the [ STATUS 2 REGISTER ]. EXT-bit
is usually at “1” right after the reset ( it becomes “0” by writing “1” at EXTRQ-bit ).
Then the decoded data is written into the [ EXTENDED DATA 1.2 REGISTER ] as shown. Data in the [ EXTENDED DATA
1.2 REGISTER ] remains in this register it is over-written.
* [ EXTENDED DATA 1 REGISTER ]
bit 7
bit 6
bit 5
EXT7
EXT6
EXT5
bit 4
EXT4
bit 3
EXT3
bit 2
EXT2
bit 1
EXT1
bit 0
EXT0
* [ EXTENDED DATA 2 REGISTER ]
bit 7
bit 6
bit 5
EXT15
EXT14
EXT13
bit 4
EXT12
bit 3
EXT11
bit 2
EXT10
bit 1
EXT9
bit 0
EXT8
Rev.0
58
2003/01