Functional Description
Microsemi Proprietary and Confidential UG0677 User Guide Revision 9.0 13
DFE can also be set in static mode where the user can specify the exact DFE coefficients required by the
design. DFE Coefficients are set through PDC commands (see DFE Coefficients, page 104) can be used
from the register rather than from calibration. This mode does not expose the CALIB_REQ pin or any of
the pins to trigger auto-calibration or incremental calibration.
Incremental DFE is another option of calibration to incrementally improve the performance of the DFE
path. A specific PF_XCVR_ERM core is generated by Libero which, exposes the required pins to trigger
the incremental calibration.
Two algorithms are available for re-calibration.
• Data Eye clock centering Re-calibration
• DFE Coefficient Re-calibration.
Both algorithms do eye-centering, however, they are independent operations. Full calibration and Static
calibration are mutually exclusive and Incremental calibration of any of the two algorithms can only be
applied after at least one ‘Full calibration’.
Users can enable one or both choices in PF_XCVR_ERM configurator depending on the mode of
operation and the receiver calibration options selected.
The calibration blocks are used at power-up calibration and user demanded recalibration. These are
Libero configured. The following table lists the summary of mode of operations.
Examples of the specific types of calibration are:
ON_DEMAND
The receiver does not calibrate automatically. The user must initiate an on-demand calibration using
either the wires on the XCVR interface or over the DRI. If the specific design performs dynamic
reconfiguration using DRI, then the user routine must perform a recalibration each time the XCVR locks
to a new data rate and/or data pattern.
In CDR modes where data rate ≤ 10312.5 Mbps, the device performs DC offset calibration of the CDR
and the CTLE calibration when the user toggles the CALIB_REQ port. When calibration is completed, the
best DC offset and RX CTLE settings are applied to the receiver.
In DFE modes where data rate > 10312.5 Mbps, the device performs the same optimization as in CDR
mode with the addition on performing full DFE calibration of the DFE coefficients. When calibration is
completed the best DC offset, RX CTLE, and DFE coefficient settings are applied to the receiver.
To successfully complete the RX (CTLE) calibration process, the reference clocks must be stable and
free running at device power-up and valid data must be present at the transceiver Rx input buffers. The
data should be approximately the actual data that is received but does not need to be any particular data
pattern. However, for DFE, calibration can be dependent on the data pattern used at DFE calibration. For
Table 3 • Mode of Operations
CDR Mode
(Data Rate ≤ 10312.5 Mbps) Incrementally Re-calibrate Data Eye
Incrementally Re-calibrate DFE
Coefficients
None_CDR Not supported Not supported
On Demand Supported Not supported
On Demand and First Lock Supported Not supported
None_DFE Not supported Not supported
DFE Mode
(Data Rate > 10312.5 Mbps) Incrementally Re-calibrate Data Eye
Incrementally Re-calibrate DFE
Coefficients
None_CDR Not supported Not supported
On Demand Supported Supported
On Demand and First Lock Supported Supported
None_DFE Not supported Not supported
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