adv7189b Analog Devices, Inc., adv7189b Datasheet - Page 53

• Manufacturer Part Number: adv7189b
• Description: Multiformat Sdtv Video Decoder
• Manufacturer: Analog Devices, Inc.

Table 65. Data Byte Allocation
2×
1
1
0
0
Gemstar Bit Names
x
x
x
x
x
x
x
DID. The data identification value is 0x140 (10-bit value).
Care has been taken that in 8-bit systems, the 2 LSBs do
not carry vital information.
EP and !EP. The EP bit is set to ensure even parity on the
data-word D[8:0]. Even parity means there is always an
even number of 1s within the D[8:0] bit arrangement.
This includes the EP bit. !EP describes the logic inverse of
EP and is output on D[9]. The !EP is output to ensure that
the reserved codes of 00 and FF cannot happen.
EF. Even field identifier. EF = 1 indicates that the data was
recovered from a video line on an even field.
2×. This bit indicates whether the data sliced was in
Gemstar 1× or 2× format. A high indicates 2× format.
Line[3:0]. This entry provides a unique code for each of the
possible 16 source lines of video from which Gemstar data
may have been retrieved. See
DC[1:0]. Data count value. The number of user data-words
in the packet divided by 4. The number of user data-words
(UDW) in any packet must be an integral number of 4.
Padding is required at the end if necessary (requirement
as set in ITU-R BT.1364). See
The 2× bit determines whether the raw information
retrieved from the video line was 2 or 4 bytes. The state
of the GDECAD bit affects whether the bytes are trans-
mitted straight (that is, two bytes transmitted as two bytes)
or whether they are split into nibbles (that is, two bytes
transmitted as four half bytes). Padding bytes are then
added where necessary.
Raw Information Bytes
Retrieved from the Video Line
4
4
2
2
T able 74 and
2 2 5 H
T able 65.
2 2 7 H
2 2 6 H
T able 75.
GDECAD
0
1
0
1
Rev. B | Page 53 of 104
User Data-Words
(Including Padding)
8
4
4
4
x
T able 66 to
2 2 8 H
Gemstar 2× Format, Half-Byte Output
Half-byte output mode is selected by setting CDECAD = 0;
full-byte output mode is selected by setting CDECAD = 1.
See the
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
Address 0x4C[0] section.
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 2 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 that the reserved values of 0x00 and 0xFF do not
occur.
G DECAD Gemstar Decode Ancillary Data Format,
2 3 0 H
G DECAD Gemstar Decode Ancillary Data Format,
2 3 1 H
T able 69 outline the possible data packages.
2 2 9 H
Padding Bytes
0
0
0
2
ADV7189B
DC[1:0]
10
01
01
01