AK8811_12 Datasheet, PDF (18/36 Pages) Asahi Kasei Microsystems – NTSC/PAL Digital Video Encoder

ASAHI KASEI
[AK8811/12]
♦ Closed Caption and Extended Data
AK8811/12 supports both Closed Captioning and Extended Data. They are controlled “ON”
or ”OFF” respectively by [ Video Process 2 Register(02H) ]. Each data consists of 2 continuous
bytes register( Closed Caption R (16H,17H) ), and it is recognized as the data is renewed when
the second byte(17H register) is written in the register. After the data is renewed, AK8811/12
encodes Closed Captioning and Extended Data at the designated line. If the data isn’t renewed,
AK8811/12 outputs “ASCII-NULL” code. The data is supposed as Odd Parity and 7 bit US-
ASCII code. Host should provide a parity bit.
*In PAL encoding mode, AK8811/12 outputs them at the same timing and same pattern as NTSC.
*The line where Closed Captioning data is encoded is as follows.
525/60 System (SMPTE) 625/50 System (CCIR)
Closed Caption
21 Line default
21 Line default
Extended Data
284 Line default
334 Line default
10.5±0.25uS
12.91 uS
50±2IRE
40IRE
7 Cycles of
0.5035MHz
(Clock RUN-IN)
10.003±0.25uS
27.382 uS
TWO 7-Bit+PARITY
ASCII Characters
(DATA)
P
P
S
A
A
R
R
T
I
I
T
T
A
Y
Y
240±48nsec
RISE/FALL TIMES
(2T BAR SHAPING)
( 33.764 uS )
61 uS
Fig. 4 Closed Captioning Wave form
Rev.1.1
18
2000/01