GS2972 Datasheet, PDF (76/125 Pages) Semtech Corporation – 3G/HD/SD-SDI Serializer with Complete SMPTE Audio & Video Support

The insertion of TRS ID words only take place if the IOPROC_EN/DIS pin is HIGH and the
SMPTE_BYPASS pin is HIGH.
In addition to this, the GS2972 requires the TRS_INS bit to be set LOW in the IOPROC
register.
If the TIM_861 pin is HIGH, then the timing circuits are locked to CEA-861 timing.
4.9.6 HD and 3G Line Number Calculation and Insertion
The GS2972 is capable of line number generation and insertion, in accordance with the
relevant HD video standard, as determined by the automatic video standard detector.
Line numbers are inserted into both the Y and C channels.
Note: Line number generation and insertion only occurs in HD and 3G modes
(RATE_SEL0 = LOW).
The insertion of line numbers only take place if the IOPROC_EN/DIS pin is HIGH and
SMPTE_BYPASS pin is HIGH.
In addition to this, the GS2972 requires the LNUM_INS bit to be set LOW in the IOPROC
register.
4.9.7 Illegal Code Re-Mapping
The GS2972 detects and corrects illegal code words within the active picture area.
All codes within the active picture (outside the horizontal and vertical blanking periods),
between the values of 3FCh and 3FFh are re-mapped to 3FBh. All codes within the active
picture area between the values of 000h and 003h are remapped to 004h.
8-bit TRS code words are re-mapped to 10-bit values.
The illegal code re-mapping will only take place if the IOPROC_EN/DIS pin is HIGH and
SMPTE_BYPASS is HIGH.
In addition to this, the GS2972 requires the ILLEGAL_WORD_REMAP bit to be set LOW
in the IOPROC register.
Note: Due to the architecture of the GS2972 serializer, illegal code words appearing in
the middle of a line that look like TRS sequences will be treated as such by the device.
For example, any sequence in the middle of a line that produces 3FFh 000h 000h
followed by another 10-bit word will be treated as a TRS, even if that following word
does not match the XYZh code words allowed by SMPTE.
To avoid this issue, any groupings of words that look like TRS sequence must be kept out
of the active picture portion of the video line or it will not be remapped.
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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