gs9076 Gennum Corporation, gs9076 Datasheet - Page 19

• Manufacturer Part Number: gs9076
• Description: Sd-sdi Automatic Reclocker With Dual Differential Outputs
• Manufacturer: Gennum Corporation

4.6 4:1 Input Mux
4.7 Automatic and Manual Data Rate Selection
The 4:1 input mux allows the connection of four independent streams of video/data.
There are four differential inputs (DDI[3:0] and DDI[3:0]). The active channel can
be selected via the DDI_SEL[1:0] pins.
given state at DDI_SEL[1:0].
Table 4-1: Bit Pattern for Input Select
The DDI inputs are designed to be DC interfaced with the output of the GS9074A
Cable Equalizer. There are on chip 50Ω termination resistors which come to a
common point at the DDI_VT pins. Connect a 10nF capacitor to this pin and
connect the other end of the capacitor to ground. This terminates the transmission
line at the inputs for optimum performance.
If only one input pair is used, connect the unused positive inputs to +3.3V and leave
the unused negative inputs floating. This helps to eliminate crosstalk from potential
noise that would couple to the unused input pair.
The GS9076 can be configured to manually lock to a specific data rate or
automatically search for and lock to the incoming data rate. The AUTO/MAN pin
selects automatic data rate detection mode (Auto mode) when HIGH and manual
data rate selection mode (Manual mode) when LOW.
In Auto mode, the SS[2:0] bi-directional pins become outputs and the bit pattern
indicates the data rate that the PLL is locked to (or previously locked to).
In Manual mode, the data rate can be programmed and the SS[2:0] pins become
inputs. In this mode, the PLL will only lock to the data rate selected.
Table 4-2
Manual mode) or the data rate that the PLL has locked to (in Auto mode).
Table 4-2: Data Rate Indication/Selection Bit Pattern
44617 - 1
shows the SS[2:0] pin settings for either the data rate selected (in
DDI_SEL[1:0]
January 2008
SS[2:0]
00
01
10
11
010
Table 4-1
shows the input selected for a
Data Rate (Mb/s)
Selected Input
GS9076 Data Sheet
DDI0
DDI1
DDI2
DDI3
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