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Ancillary Data
7
Ancillary Data
An option is available to enable transmission of sliced VBI data as ancillary data in the ITU-R BT.656
video data stream. In this mode, the sliced data is inserted on the Y[7:0] output terminals during the
horizontal blanking interval. An 8-byte header containing information about the sliced data is also inserted
in the data stream prior to the sliced data. The header includes a 00h, FFh, FFh preamble that identifies
the data as VBI ancillary data, so the host or backend must be able to distinguish between this preamble
and the ITU-R BT.656 embedded sync codes (FFh, 00h, 00h, E/SAV). The first header byte is inserted
immediately following the EAV code during the horizontal blanking interval of the digital line where it
occurred. The ancillary data header is summarized in
The ancillary data mode is enabled by setting bit 6 in the appropriate line-mode register to a logic 1 and
the host-access enable bit (bit 0) in register CDh to a logic 0. When the ancillary data mode is enabled in
register CDh, sliced data is not routed to the internal 512-byte FIFO.
Table 5. Ancillary Data Header
Byte No.
D7 (MSB)
D6
D5
D4
D3
D2
D1
D0 (LSB)
Description
0
0
0
0
0
0
0
0
0
Ancillary data preamble
1
1
1
1
1
1
1
1
1
2
1
1
1
1
1
1
1
1
3
NEP
EP
0
1
0
DID2
DID1
DID0
Data ID (DID)
4
NEP
EP
F5
F4
F3
F2
F1
F0
Secondary data ID (SDID)
5
NEP
EP
N5
N4
N3
N2
N1
N0
Number of 32 bit data (NN)
6
Video line # [7:0]
Internal Data ID0 (IDID0)
7
0
0
0
Data error
Match #1
Match #2
Video line # [9:8]
Internal Data ID1 (IDID1)
8
1. Data
Data byte
1
st
word
9
2. Data
Data byte
10
3. Data
Data byte
11
4. Data
Data byte
...
...
...
m-1. Data
Data byte
N
th
word
m. data
Data byte
CS [7:0]
Checksum
4N+7
0
0
0
0
0
0
0
0
Fill byte
EP:
Even parity for D0-D5
NEP:
Negate even parity
DID:
91h:
Sliced data from the vertical blanking interval of first field
53h:
Sliced data from outside of the vertical blanking interval of first field
55h:
Sliced data from the vertical blanking interval of second field
97h:
Sliced data from outside of the vertical blanking interval of second field
SDID:
This field holds the data format taken from the line-mode register of the corresponding line.
NN:
Number of Dwords beginning with byte 8 through 4N+7. Note that each Dword is 4 bytes.
IDID0:
Transaction video line number [7:0]
IDID1:
Bit
Transaction video line number [9:8].
0/1:
Bit 2:
Match 2 flag.
Bit 3:
Match 1 flag.
Bit 4:
Value = 1 if a single error was detected in the EDC block. Value = 0 if no error was detected.
CS:
Sum of D0-D7 of 1.Data through last data byte.
Fill byte:
Fill byte makes a multiple of 4 bytes from byte zero to last fill byte.
Note: The number of bytes (m) varies depending on the VBI data service.
9
SLEA104 – July 2010
TVP5154A VBI Quick Start
Copyright © 2010, Texas Instruments Incorporated
