GS2972 Datasheet, PDF (34/125 Pages) Semtech Corporation – 3G/HD/SD-SDI Serializer with Complete SMPTE Audio & Video Support

4.2.3 Parallel Input in Data-Through Mode
Data-Through mode is enabled when the SMPTE_BYPASS pin and the DVB_ASI pin are
LOW.
In this mode, data at the input bus is serialized without any encoding, scrambling or
word alignment taking place.
The input data width is controlled by the setting of the 20BIT/10BIT pin as shown in
Table 4-2 above.
Note: When in HD 10-bit mode, asserting the SMPTE_BYPASS LOW to put the device in
SMPTE-BYPASS mode will create video errors. If the user desires to use the device as a
simple serializer in HD 10-bit mode, all video processing features may be disabled by
setting the IOPROC_EN/DIS pin LOW.
4.2.4 Parallel Input Clock (PCLK)
The frequency of the PCLK input signal of the GS2972 is determined by the input data
format and operating mode selection.
Table 4-3 below lists the input PCLK rates and input signal formats according to the
external selection pins for the GS2972.
Table 4-3: GS2972 PCLK Input Rates
Input Data Format
20-bit demultiplexed
3G format
20-bit demultiplexed
HD format
20-bit data Input
3G format
20-bit data input
HD format
20-bit demultiplexed
SD format
20-bit data input
SD format
10-bit multiplexed
3G DDR format
10-bit multiplexed
HD format
10-bit data input
HD format
10-bit multiplexed
SD format
20BIT/10BIT
HIGH
HIGH
HIGH
HIGH
HIGH
HIGH
LOW
LOW
LOW
LOW
Pin Settings
RATE_
SEL0
RATE_
SEL1
SMPTE_
BYPASS
LOW
HIGH
HIGH
LOW
LOW
HIGH
LOW
HIGH
LOW
LOW
LOW
LOW
HIGH
X
HIGH
HIGH
X
LOW
LOW
HIGH
HIGH
LOW
LOW
HIGH
LOW
LOW
LOW
HIGH
X
HIGH
DVB-ASI
PCLK Rate
X
X
LOW
LOW
LOW
LOW
LOW
LOW
LOW
X
148.5 or 148.5/1.001MHz
74.25 or 74.25/1.001MHz
148.5 or 148.5/1.001MHz
74.25 or 74.25/1.001MHz
13.5MHz
13.5MHz
148.5 or 148.5/1.001MHz
148.5 or 148.5/1.001MHz
148.5 or 148.5/1.001MHz
27MHz
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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