GS2972 Datasheet, PDF (67/125 Pages) Semtech Corporation – 3G/HD/SD-SDI Serializer with Complete SMPTE Audio & Video Support

4.8.2 3G ANC Insertion
4.8.2.1 Level A Mode
When operating in 3G (RATE _SEL0 = LOW, RATE_SEL1 = HIGH) Level A mode, the
GS2972 inserts VANC or HANC data packets into Data Stream One (default) or Data
Stream Two.
The data stream for insertion is selectable for each of the ANC insertion lines selected via
the host interface. Data Stream One is selected when the STREAM_TYPE_1 bit in the
register associated with the insertion line is set LOW (default). Data Stream Two is
selected when the STREAM_TYPE_1 bit associated with the insertion line is set HIGH.
ANC data should be placed in DS1 first in Level A mode, and only in DS2 as an overflow
if DS1 is full. Data insertion starts at the first available location in the HANC space
following any audio and pre-existing arbitrary data packets.
All Data Words identified by the user are inserted in a contiguous fashion starting at the
first available data space. HANC data insertion terminates when all Data Words
identified by the user have been inserted; or by the start of the four word TRS SAV code,
regardless of the number of Data Words actually inserted. The rest of the packet will be
ignored.
Vertical Ancillary data (VANC), is inserted into the data stream on the video line(s)
defined by the user. Data insertion starts at the first active pixel immediately following
the last word of the TRS SAV code.
All Data Words identified by the user are inserted in a contiguous fashion, starting at the
first active pixel. VANC data insertion terminates when all data words identified by the
user have been inserted; or by the start of the four word TRS EAV code, regardless of the
number of Data Words actually inserted.
The total number of Data Words to be inserted and the line number on which the ANC
data insertion takes place is provided by the user via the host interface as part of the
configuration of the ANC data insertion function.
The user data for insertion is provided via the host interface register STREAM_TYPE_1
(02Dh).
GS2972 3G/HD/SD-SDI Serializer with Complete
SMPTE Audio & Video Support
Final Data Sheet Rev. 9
GENDOC-047479 September 2013
www.semtech.com
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