GS6152 Datasheet, PDF (18/80 Pages) Semtech Corporation – Multi-Rate 6G UHD-SDI

Table 4-2: Pin and Register Settings for Input Selection (Continued)
Register Settings
INPUT_SELECTION_CONTROL
7_h[9:8]
DDI_SELECT
7_h[11]
11
1
Note: ‘X’ indicates ‘Do Not Care’
DDI_SELECT
7_h[10]
1
Pin Settings
Differential
DDI_SEL1
DDI_SEL0/
STROBE
High-speed
Input Selected
on
X
LOW-to-HIGH DDI3, DDI3
transition
The DDI_SEL0/STROBE and DDI_SEL1 pins include internal pull-downs, which pulls the
input voltage LOW if either pin is unconnected.
When using the STROBE pre-select method (#3 above), the pre-selected input buffer
and trace EQ is powered up in advance of the STROBE pulse.
4.2 Reference Clock
The GS6152 can operate with or without an external frequency reference. For
applications requiring rapid asynchronous locking, a 27MHz reference or crystal is
required.
The PLL lock times for both referenceless and external crystal reference operation are
given in Table 2-3: AC Electrical Characteristics.
If a reference is connected to the XTAL_CLK_IN pin or a crystal is connected to the
XTAL_CLK_IN and XTAL_CLK_OUT pins of the device, it will automatically be used as the
reference frequency for rapid asynchronous lock. If XTAL_CLK_IN is not connected to a
crystal, XTAL_CLK_OUT must be left unconnected.
The XTAL_CLK_IN pin operates correctly when connected directly to the
XTAL_BUF_OUT from another GS6152, or a 27MHz output of a different device.
4.3 Signal Monitoring
The GS6152 measures and reports the following signal status and quality monitoring
parameters:
• Loss of Signal
• Lock Detection
• Rate Detection
• Low/High Bit Rate Detection
GS6152
Final Data Sheet
PDS-060984
Rev.2
July 2015
www.semtech.com
18 of 80
Semtech
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