GX4002 Datasheet, PDF (16/74 Pages) Gennum Corporation – Dynamic on-chip power management control

CH0RATEDETPERIOD (address 68) and CH1RATEDETPERIOD (address 73) control the
frequency at which the automatic rate detection block checks the lock state of the PLL.
The recommended setting for shortest lock time is 1001b.
3.1.1.4 Application-Dependent Rate Select Profiles
The RATEDETFCGBEN and RATEDETFCGBENVAL bits indicate whether the
application traffic is running Fibre Channel, Ethernet or unspecified (for example: the
transceiver may be required to handle either Fibre Channel or Ethernet traffic in mission
mode). The default setting is Fibre Channel traffic.
Register Name
Register
Address^d
CH0RDET_REG1
67
Parameter Name
RATEDETFCGBEN
RATEDETFCGBENVAL
Bit
Position
Access
2:2
RW
3:3
RW
Reset Value^b
1
1
Valid
Range^d
Function
When HIGH, the application is Fibre
0-1
Channel. When LOW, the application is
Ethernet.
0-1
When HIGH, indicates that RATEDETFCGBEN
is valid. When LOW, it is ignored.
Table 3-2: Summary of Rate Selection and Rate Detection Control
CH1PLLRATESELVAL
CH0PLLRATESELVAL
0
0
1
1
RATEDETFCGBENVAL
0
1
0
1
Data Rate
Configuration Profile
Undefined
Auto Rate Detect
Auto Rate Detect
Fixed rate determined by the
combination of
RATEDETFCGBEN and rate
select (hard or soft)
Undefined
Profile selected based on
detected rate
Profile selected by hard or soft
rate select
Profile selected by hard or soft
rate select
3.1.2 Auto Retimer Bypass
The GX4002 supports an automatic rate detect feature for legacy Fibre Channel data
rates when configured in 16G mode. Upon enabling the automatic rate detect feature,
the device constantly monitors incoming data for a valid 14.025Gb/s data rate. If the
input data rate is a legacy Fibre Channel rate, the CDR is automatically bypassed.
While the automatic rate detect feature is enabled, and the CDR is in bypass mode, the
device continues monitoring the incoming data rate. If the data rate changes to
14.025Gb/s, the CDR goes back into retimed mode.
The auto retimer bypass feature also applies to Ethernet mode.
GX4002 2x2 14.025Gb/s Crosspoint Switch with Trace
Equalization and Output De-Emphasis
Data Sheet
55972 - 0
March 2012
16 of 74
Proprietary & Confidential