GS2961A Datasheet, PDF (72/104 Pages) Gennum Corporation – Ancillary data extraction

Additionally, the device sets the active picture and full field CRC 'V' bits HIGH in the
EDH packet. The AP_CRC_V and FF_CRC_V register bits only report the received EDH
validity flags.
EDH FF and AP CRC's are only inserted when the device is operating in SD mode, and if
the EDH data packet is detected in the received video data.
Although the GS2961A modifies and inserts EDH CRC's and EDH packet checksums,
EDH error flags are only updated when the EDH_FLAG_UPDATE_MASK bit is LOW.
This feature is enabled in SD mode, when the IOPROC_EN/DIS pin is HIGH and the
EDH_CRC_INS_MASK bit in the IOPROC_1 register is set LOW.
4.18.6 Illegal Word Re-mapping
All words within the active picture (outside the horizontal and vertical blanking
periods), between the values of 3FCh and 3FFh are re-mapped to 3FBh. All words within
the active picture area between the values of 000h and 003h are remapped to 004h.
This feature is enabled when the IOPROC_EN/DIS pin is HIGH and the
ILLEGAL_WORD_REMAP_DSX_MASK bit in the IOPROC_X register is set LOW.
4.18.7 TRS and Ancillary Data Preamble Remapping
8-bit TRS and ancillary data preambles are re-mapped to 10-bit values. 8-bit to 10-bit
mapping of TRS headers is only supported if the TRS values are 3FC 000 000. Other
values such as 3FD, 3FE, 3FF, 001, 002 and 003 are not supported. This feature is enabled
by default, and cannot be disabled via the IOPROC_X register.
4.18.8 Ancillary Data Extraction
Ancillary data may be extracted externally from the GS2961A output stream using the
Y/1ANC and C/2ANC signals, and external logic.
As an alternative, the GS2961A includes a FIFO, which extracts ancillary data using read
access via the host interface to ease system implementation. The FIFO stores up to 2048
x 16 bit words of ancillary data in two separate 1024 word memory banks.
The device writes the contents of ANC packets into the FIFO, starting with the first
Ancillary Data Flag (ADF), followed by up to 1024 words.
All Data Identification (DID), Secondary Data Identification (SDID), Data Count (DC),
user data, and checksum words are written into the device memory.
The device detects ancillary data packet DID's placed anywhere in the video data
stream, including the active picture area.
Ancillary data from the Y channel or Data Stream One is placed in the Least Significant
Word (LSW) of the FIFO, allocated to the lower 8 bits of each FIFO address.
Ancillary data from the C channel or Data Stream Two is placed in the Most Significant
Word (MSW) (upper 8 bits) of each FIFO address.
NOTE: Please refer to the ANC insertion and Extraction Application Note (Doc ID:
53410), for discrete steps and example of Ancillary data extraction.
GS2961A 3Gb/s, HD, SD SDI Integrated Receiver
Data Sheet
54385 - 2
September 2012
72 of 104