GS2972 Datasheet, PDF (33/125 Pages) Semtech Corporation – 3G/HD/SD-SDI Serializer with Complete SMPTE Audio & Video Support

4.2.1 Parallel Input in SMPTE Mode
When the device is operating in SMPTE mode (SMPTE_BYPASS = HIGH), data must be
presented to the input bus in either multiplexed or demultiplexed form, depending on
the setting of the 20BIT/10BIT pin.
When operating in 20-bit mode (20BIT/10BIT = HIGH), the input data format must be
word aligned, demultiplexed Luma and Chroma data (SD or HD), or word aligned
demultiplexed Data Stream One and Data Stream Two data (3G).
In 3G Level B mode, by default, the device takes Data Stream One input from data port
DIN[19:10] and Data Stream Two input from DIN[9:0].
When operating in 10-bit mode (20BIT/10BIT = LOW), the input data format must be
multiplexed Luma (Y) and Chroma (C) data (SD, HD), or multiplexed Data Stream One
and Data Stream Two data (3G). C words precede Y words, and Data Stream 2 words
precede Data Stream 1 words. In this mode, the data must be presented on the
DIN[19:10] pins. The DIN[9:0] inputs are ignored.
In 3G 10-bit mode, the device operates in DDR mode. That is, the input data is sampled
on both the rising and falling edges of the PCLK. In 3G mode, Data Stream Two words
precede Data Stream One words. The Data Stream Two words are sampled on the rising
edge of the input PCLK, and the Data Stream One words are sampled on the following
falling edge. H, V and F timing pulses, if used, are sampled on the rising edge of PCLK.
4.2.1.1 Input Data Format in SDTI Mode
SDTI and HD-SDTI are a sub-set of SDI and HD-SDI formats. They may contain SDTI data
on any line in the frame. Those lines which contain SDTI or HD-SDTI data are identified
with an SDTI or HD-SDTI header packet in the HANC space.
The GS2972 does not differentiate between a signal carrying video and a signal carrying
SDTI or HD-SDTI data in SD or HD formats. The user is responsible for ensuring that the
headers and data are not corrupted.
4.2.2 Parallel Input in DVB-ASI Mode
The GS2972 is in DVB-ASI mode when the SMPTE_BYPASS pin is set LOW, the DVB_ASI
pin is set HIGH, and the RATE_SEL0 pin is set HIGH. In this mode, all SMPTE processing
features are disabled.
When operating in DVB-ASI mode, the device must be set to 10-bit mode by setting the
20BIT/10BIT pin LOW. The device will accept 8-bit data words on DIN[17:10], where
DIN17 = HIN is the most significant bit of the encoded transport stream data and
DIN10 = AIN is the least significant bit. In addition, DIN19 and DIN18 will be configured
as the DVB-ASI control signals INSSYNCIN and KIN respectively.
DIN19 = INSSYNCIN
DIN18 = KIN
DIN17~10 = HIN ~ AIN where AIN is the least significant bit of the transport stream data.
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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