Analog Devices ADV7181BCP Manual page 52

ADV7181B
•
CS[8:2]. The checksum is provided to determine the
integrity of the ancillary data packet. It is calculated by
summing up D[8:2] of DID, SDID, the data count byte, and
all UDWs, and ignoring any overflow during the
summation. Since all data bytes that are used to calculate
the checksum have their two LSBs set to 0, the CS[1:0] bits
are also always 0.
!CS[8] describes the logic inversion of CS[8]. The value
!CS[8] is included in the checksum entry of the data
packet to ensure the reserved values of 0x00 and 0xFF do
not occur.
Table 65 to Table 68 outline the possible data packages.
Table 65. Gemstar 2× Data, Half-Byte Mode
Byte D[9] D[8]
0 0 0
1 1 1
2 1 1
3 0 1
4 !EP EP
5 !EP EP
6 !EP EP
7 !EP EP
8 !EP EP
9 !EP EP
10 !EP EP
11 !EP EP
12 !EP EP
13 !EP EP
14 !CS[8] CS[8]
Table 66. Gemstar 2× Data, Full-Byte Mode
Byte D[9] D[8]
0 0 0
1 1 1
2 1 1
3 0 1
4 !EP EP
5 !EP EP
6
7
8
9
10 !CS[8] CS[8]
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D[7] D[6] D[5]
0 0 0
1 1 1
1 1 1
0 1 0
EF 1
0 0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
CS[7] CS[6] CS[5]
D[7] D[6] D[5] D[4]
0 0 0 0
1 1 1 1
1 1 1 1
0 1 0 0
EF 1
0 0 0 0
Gemstar Word1[7:0]
Gemstar Word2[7:0]
Gemstar Word3[7:0]
Gemstar Word4[7:0]
CS[7] CS[6] CS[5] CS[4]
Rev. B | Page 52 of 100
Gemstar 2× Format, Half-Byte Output Mode
Half-byte output mode is selected by setting CDECAD = 0;
full-byte output mode is selected by setting CDECAD = 1.
See the GDECAD Gemstar Decode Ancillary Data Format,
Address 0x4C[0] section.
Gemstar 1× Format
Half-byte output mode is selected by setting CDECAD = 0;
full-byte output mode is selected by setting CDECAD = 1.
See the GDECAD Gemstar Decode Ancillary Data Format,
Address 0x4C[0] section.
D[4] D[3] D[2]
0 0 0
1 1 1
1 1 1
0 0 0
Line[3:0]
0 1 0
Gemstar Word1[7:4]
Gemstar Word1[3:0]
Gemstar Word2[7:4]
Gemstar Word2[3:0]
Gemstar Word3[7:4]
Gemstar Word3[3:0]
Gemstar Word4[7:4]
Gemstar Word4[3:0]
CS[4] CS[3] CS[2]
D[3] D[2] D[1]
0 0 0
1 1 1
1 1 1
0 0 0
Line[3:0] 0
0 1 0
0
0
0
0
CS[3] CS[2] CS[1]
D[1] D[0] Description
0 0 Fixed preamble
1 1 Fixed preamble
1 1 Fixed preamble
0 0 DID
0 0 SDID
0 0 Data count
0 0 User data-words
0 0 User data-words
0 0 User data-words
0 0 User data-words
0 0 User data-words
0 0 User data-words
0 0 User data-words
0 0 User data-words
CS[1] CS[0] Checksum
D[0] Description
0 Fixed preamble
1 Fixed preamble
1 Fixed preamble
0 DID
0 SDID
0 Data count
0 User data-words
0 User data-words
0 User data-words
0 User data-words
CS[0] Checksum