Data Sheet
ADV7180
The ancillary data packet sequence is explained in Table 74 and
Table 75. 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 Code 0x00 and Code 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 can be introduced to make the total
number of UDWs divisible by 4.
The following abbreviations are used in Table 74 and Table 75:
•
•
EP—Even parity for Bit B8 to Bit B2. 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 that include the following:
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 74. 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
3
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
EP
EP
0
I2C_DID6_2[4:0]
0
0
DID (data identification
word)
4
EP
EP
I2C_SDID7_2[5:0]
0
0
SDID (secondary data
identification word)
5
EP
EP
EP
EP
EP
EP
EP
EP
EP
EP
EP
EP
EP
EP
EP
EP
EP
EP
EP
EP
0
0
DC[4:0]
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]
LINE_NUMBER[4:0]
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
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
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
0
0
1
B8
Checksum (CS)
CS (checksum word)
Rev. G | Page 57 of 120
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