DS125DF1610 Datasheet, PDF (73/81 Pages) Texas Instruments – 9.8 to 12.5 Gbps 16-Channel Retimer

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DS125DF1610
SNLS482A – APRIL 2014 – REVISED DECEMBER 2015
8.3 Initialization Setup
The typical device initialization sequence for a DS125DF1610 includes the following:
• Shared Register Configurations:
– Reference Clock Divider Setting (default is 25MHz)
– Lock Sequencer Configuration (default is 8 channels allowed lock concurrently)
• Channel Register Configurations repeated for all desired channels:
– CDR reset
– Adapt Mode Configuration
– Data rate selection
– Output driver VOD and FIR configuration
– Optional Continuous DFE adaption configuration
– Optional Interrupt enable
– Optional Reference clock loop through enable
– Optional Cross point switch configuration
– CDR reset release
8.3.1 Data Rate Selection (Rate/Sub-Rate Table)
The data rates for the DS125DF1610 must be known and programmed into each desired channel. The
DS125DF1610 will only lock to programmed data rates and the programmed divider settings. For ease of use
several common data rates have been preprogrammed into the DS125DF1610 along with the associated sub-
rates for those various standards. These rate/sub-rate settings comprise the Rate/Sub-rate Table 18. Note that
each channel operates independently, so different channels in the DS125DF1610 can operate at different data
rates at the same time.
The Rate/Sub-rate Table 18 for the DS125DF1610 shown below includes all of the available preprogrammed
data rates and associated divider groupings.
CHANNEL REGISTER
0x2F[7:4] SETTING
0x6
0x7
0x8
0x9
0xA
0xB
Table 18. Rate/Sub-Rate Options
STANDARD
Custom
Interlaken
CPRI 1
CPRI 2
Infiniband
Ethernet
DATA RATES (Gbps)
11.5
12.5, 6.25, 3.125
9.8304, 4.9152, 2.4576
6.144, 3.072
10, 5, 2.5
10.3125, 1.25
FIRST GROUP DIVIDER
SETTINGS
1
1, 2, 4
1, 2, 4
2, 4
1, 2, 4
8
SECOND GROUP
DIVIDER SETTINGS
1
1, 2, 4
1, 2, 4
2, 4
1, 2, 4
1
8.3.2 Data Rate Selection (Manual Programming)
The DS125DF1610 is capable of supporting any data rate within the specified range of 9.8 Gbps to 12.5 Gbps
including the divide by 2, 4, and 8 sub-rates of this range. If it is desired to operate the DS125DF1610 at a data
rate or data rate and sub-rate combination that is not available in the Rate/Sub-rate Table 18, then these desired
data rates can be programmed into the device manually.
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