ADV7181BCP Analog Devices Inc, ADV7181BCP Datasheet - Page 50

• Manufacturer Part Number: ADV7181BCP
• Description: IC VIDEO DECODER NTSC 64-LFCSP
• Manufacturer: Analog Devices Inc
• Type: Video Decoderr

Specifications of ADV7181BCP

• Applications: Recorders, Set-Top Boxes
• Voltage - Supply, Analog: 3.15 V ~ 3.45 V
• Voltage - Supply, Digital: 1.65 V ~ 2 V
• Mounting Type: Surface Mount
• Package / Case: 64-LFCSP
• Adc/dac Resolution: 9b
• Screening Level: Industrial
• Package Type: LFCSP EP
• Pin Count: 64
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With: EVAL-ADV7181BEB - BOARD EVALUATION FOR ADV7181
• Lead Free Status / RoHS Status: Compliant, Contains lead / RoHS non-compliant

ADV7181
VBI DATA DECODE
The following low data rate VBI signals can be decoded by the
ADV7181:
•
•
•
•
•
The presence of any of the above signals is detected and, if
applicable, a parity check is performed. The result of this testing
is contained in a confidence bit in the VBI Info[7:0] register.
Users are encouraged to first examine the VBI Info register
before reading the corresponding data registers. All VBI data
decode bits are read-only.
All VBI data registers are double-buffered with the field signals.
This means that data is extracted from the video lines and
appears in the appropriate I
transition. They are then static until the next field.
The user should start an I
examining the VBI Info register. Then, depending on the data
detected, the appropriate data registers should be read.
The data registers are filled with decoded VBI data even if their
corresponding detection bits are low; it is likely that bits within
the decoded data stream are wrong.
Notes
•
•
WSSD Wide Screen Signaling Detected, Address 0x90 [0]
Logic 1 for this bit indicates that the data in the WSS1 and
WSS2 registers is valid.
The WSSD bit goes high if the rising edge of the start bit is
detected within a time window, and if the polarity of the parity
bit matches the data transmitted.
Table 136. WSSD Function
WSSD
0
1
Wide screen signaling (WSS)
Copy generation management systems (CGMS)
Closed captioning (CCAP)
EDTV
Gemstar 1×- and 2×-compatible data recovery
The closed captioning data (CCAP) is available in the I
registers, and is also inserted into the output video data
stream during horizontal blanking.
The Gemstar-compatible data is not available in the I
registers, and is inserted into the data stream only during
horizontal blanking.
No WSS detected. Confidence in decoded data is low.
WSS detected. Confidence in decoded data is high.
Description
2
C read sequence with VS by first
2
C registers with the next field
2
C
2
Rev. B | Page 50 of 104
C
CCAPD Closed Caption Detected, Address 0x90 [1]
Logic 1 for this bit indicates that the data in the CCAP1 and
CCAP2 registers is valid.
The CCAPD bit goes high if the rising edge of the start bit is
detected within a time window, and if the polarity of the parity
bit matches the data transmitted.
Table 137. CCAPD Function
CCAPD
0
1
EDTVD EDTV Sequence Detected, Address 0x90 [2]
Logic 1 for this bit indicates that the data in the EDTV1, 2, 3
registers is valid.
The EDTVD bit goes high if the rising edge of the start bit is
detected within a time window, and if the polarity of the parity
bit matches the data transmitted.
Table 138. EDTVD Function
EDTVD
0
1
CGMSD CGMS-A Sequence Detected, Address 0x90 [3]
Logic 1 for this bit indicates that the data in the CGMS1, 2, 3
registers is valid. The CGMSD bit goes high if a valid CRC
checksum has been calculated from a received CGMS packet.
Table 139. CGMSD Function
CGMSD
0
1
CRC_ENABLE CRC CGMS-A Sequence, Address 0xB2 [2]
For certain video sources, the CRC data bits may have an
invalid format. In such circumstances, the CRC checksum
validation procedure can be disabled. The CGMSD bit goes
high if the rising edge of the start bit is detected within a time
window.
Table 140. CRC_ENABLE Function
CRC_ENABLE
0
1 (default)
Description
No CCAP signals detected. Confidence in
decoded data is low.
CCAP sequence detected. Confidence in
decoded data is high.
Description
No EDTV sequence detected. Confidence in
decoded data is low.
EDTV sequence detected. Confidence in
decoded data is high.
Description
No CGMS transmission detected, confidence
low.
CGMS sequence decoded, confidence high.
Description
No CRC check performed. The CGMSD bit goes
high if the rising edge of the start bit is detected
within a time window.
Use CRC checksum to validate the CGMS-A
sequence. The CGMSD bit goes high for a valid
checksum. ADI recommended setting.