ADV7180
The ancillary data packet sequence is explained in Table 70 and
Table 71. The nibble output mode is the default mode of output
from the ancillary stream when ancillary stream output is
enabled. This format is in compliance with ITU-R BT.1364.
EP
•
•
—The MSB, B9, is the inverse of EP. This ensures that
restricted Codes 0x00 and 0xFF do not occur.
Line_number[9:0]—The line number of the line that
immediately precedes the ancillary data packet. The line
number is from the numbering system in ITU-R BT.470.
The line number runs from 1 to 625 in a 625-line system
and from 1 to 263 in a 525-line system. Note that, due to
the vertical delay through the comb filters, the line number
on which the packet is output differs from the line number
on which the VBI data was sliced.
Data Count—The data count specifies the number of
UDWs in the ancillary stream for the standard. The total
number of user data-words is four times the data count.
Padding words may be introduced to make the total
number of UDWs divisible by 4.
These abbreviations are used in Table 70 and Table 71:
•
•
EP—Even parity for Bit B8 to Bit B2. This means that the
parity bit’s EP is set so that an even number of 1s are in
Bit B8 to Bit B2, including the parity bit, D8.
CS—Checksum word. The CS word is used to increase
confidence of the integrity of the ancillary data packet
from the DID, SDID, and DC through user data-words
(UDWs). It consists of 10 bits: a 9-bit calculated value and
B9 as the inverse of B8. The checksum value B8 to B0 is
equal to the nine LSBs of the sum of the nine LSBs of the
DID, SDID, and DC and all UDWs in the packet. Prior to
the start of the checksum count cycle, all checksum and
carry bits are preset to 0. Any carry resulting from the
checksum count cycle is ignored.
•
Table 70. Ancillary Data in Nibble Output Format
Byte
B9
B8
B7
B6
B5
0
B4
0
B3
0
B2
0
B1
0
B0
0
Description
0
1
2
0
0
0
0
Ancillary data preamble.
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
DID (data identification
word).
EP
EP
3
4
EP
EP
0
I2C_DID6_2[4:0]
0
0
0
0
SDID (secondary data
identification word).
I2C_SDID7_2[5:0]
DC[4:0]
EP
EP
EP
EP
EP
EP
EP
EP
EP
EP
.
5
EP
EP
EP
EP
EP
EP
EP
EP
EP
EP
.
0
0
0
0
0
0
0
0
0
0
0
0
.
0
0
0
0
0
0
0
0
0
0
.
Data count.
6
padding[1:0]
VBI_DATA_STD[3:0]
Line_number[9:5]
ID0 (User Data-Word 1).
ID1 (User Data-Word 2).
ID2 (User Data-Word 3).
ID3 (User Data-Word 4).
ID4 (User Data-Word 5).
ID5 (User Data-Word 6).
ID6 (User Data-Word 7).
ID7 (User Data-Word 8).
ID8 (User Data-Word 9).
7
8
Even_Field
Line_number[4:0]
9
0
0
0
0
0
0
.
0
0
0
0
0
0
.
0
0
VDP_TTXT_TYPE[1:0]
VBI_WORD_1[7:4]
10
11
12
13
14
.
VBI_WORD_1[3:0]
VBI_WORD_2[7:4]
VBI_WORD_2[3:0]
VBI_WORD_3[7:4]
.
.
.
.
Pad 0x200. These
.
.
.
.
.
.
.
.
.
.
.
padding words may be
present depending on
ancillary data type. User
data-word xx.
.
.
.
.
.
.
.
.
.
.
.
n − 3
n − 2
n − 1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
B8
Checksum
CS (checksum word).
Rev. A | Page 54 of 112
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