ADV7180
Data Sheet
Each data packet starts immediately after the EAV code of the
preceding line. Figure 50 and Table 86 show the overall structure
of the data packet.
•
Data count byte, giving the number of user data-words that
follow.
User data section.
Optional padding to ensure that the length of the user
data-word section of a packet is a multiple of four bytes
(requirement as set in ITU-R BT.1364).
Checksum byte.
•
•
Entries within the packet are as follows:
•
•
Fixed preamble sequence of 0x00, 0xFF, and 0xFF.
DID. The value for the DID marking a Gemstar or CCAP
data packet is 0x140 (10-bit value).
•
Table 86 lists the values within a generic data packet that is
output by the ADV7180 in 8-bit format.
•
SDID, which contains information about the video line
from which data was retrieved, whether the Gemstar
transmission was in 1× or 2× format, and whether it was
retrieved from an even or odd field.
DATA IDENTIFICATION
SECONDARY DATA IDENTIFICATION
DATA
COUNT
OPTIONAL PADDING CHECK
00
FF
FF
DID
SDID
USER DATA
BYTES
SUM
PREAMBLE FOR ANCILLARY DATA
USER DATA (4 OR 8 WORDS)
Figure 50. Gemstar- and CCAP-Embedded Data Packet (Generic)
Table 86. Generic Data Output Packet
Byte
D[9]
D[8]
D[7]
D[6]
D[5]
D[4]
D[3]
D[2]
D[1]
D[0]
0
Description
Fixed preamble
Fixed preamble
Fixed preamble
DID
0
0
0
0
0
0
1
1
0
0
1
1
0
0
0
1
1
0
0
1
1
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
2
1
1
1
1
1
3
0
1
0
1
0
0
4
EP
EP
EP
EP
EP
EP
EP
EP
EP
EP
CS[8]
EP
EP
EP
EP
EP
EP
EP
EP
EP
EP
CS[8]
EF
0
2X
0
0
SDID
Line[3:0]
DC[1]
5
0
0
DC[0]
0
Data count (DC)
6
0
0
0
Word1[7:4]
Word1[3:0]
Word2[7:4]
Word2[3:0]
Word3[7:4]
Word3[3:0]
Word4[7:4]
Word4[3:0]
User data-words
User data-words
User data-words
User data-words
User data-words
User data-words
User data-words
User data-words
Checksum
7
0
0
0
8
0
0
0
9
0
0
0
10
11
12
13
14
0
0
0
0
0
0
0
0
0
0
0
0
CS[7]
CS[6]
CS[5]
CS[4]
CS[3]
CS[2]
0
Table 87. Data Byte Allocation
2× Raw Information Bytes Retrieved from the Video Line
User Data-Words
(Including Padding)
GDECAD
Padding Bytes
DC[1:0]
10
01
01
01
1
1
0
0
4
4
2
2
0
1
0
1
8
4
4
4
0
0
0
2
Rev. G | Page 68 of 120
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