GS2972 Datasheet, PDF (77/125 Pages) Semtech Corporation – 3G/HD/SD-SDI Serializer with Complete SMPTE Audio & Video Support

4.9.8 SMPTE ST 352 Payload Identifier Packet Insertion
When enabled by the SMPTE_352M_INS bit in the IOPROC register, new SMPTE ST 352
payload identifier packets are inserted into the data stream. These packets are supplied
by the user via the host interface. Setting the SMPTE_352M_INS bit LOW enables this
insertion.
The device will automatically calculate the checksum and generate Version One
compliant ST 352 ancillary data preambles: DID, SDID, DBN, DC.
The SMPTE ST 352 packet is inserted into the data stream according to the line number
and sample position rules defined in the 2002 standard.
For HDTV video systems the SMPTE ST 352 packet is placed in the Y channel only.
By default (at power up or after system reset), the four VIDEO_FORMAT_IN_DS1
registers and the four VIDEO_FORMAT_OUT_DS1 registers are set to zero.
4.9.8.1 3G SMPTE ST 352 Payload Identifier Packet Insertion
When enabled by the SMPTE_352M_INS bit in the IOPROC register (000h), new
SMPTE ST 352 payload identifier packets are inserted into the data streams. Setting this
bit LOW enables insertion.
Insertion of SMPTE ST 352 packets into each data stream is controlled by the status
format describing bit, SDTI_TDM_DS1 and SDTI_TDM_DS2 for Data Stream One and
Data Stream Two. If SDTI_TDM_DS1 (default LOW) is set HIGH by the user, the GS2972
does not insert SMPTE ST 352 packets into Data Stream One. Similarly, SMPTE ST 352
packets are inserted in Data Stream Two only if SDTI_TDM_DS2 is set LOW. This allows
the user to individually disable SMPTE ST 352 packets where the data stream is carrying
an HD-SDTI or TDM signal, which must not have SMPTE ST 352 packets embedded.
Note: The user must ensure that there is sufficient space in the horizontal blanking
interval for the insertion of the SMPTE ST 352 packets. If the FIRST_AVAIL_POSITION bit
in the host interface registers is set HIGH (by default), the SMPTE ST 352 packets are
inserted in the first available position following any existing ancillary data. If the
FIRST_AVAIL_POSITION CSR bit is set LOW, then the packets are inserted immediately
after the EAV/CRC1. If the first available position is HIGH and there is insufficient space,
ST 352 packets will not be inserted.
If there are pre-existing ST 352 packets, they will be overwritten, independent of the
setting of the FIRST_AVAIL_POSITION CSR bit.
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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