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17–8 Chapter 17: Transceiver PHY Reset Controller IP Core
Timing Constraints for Reset Signals when Using Bonded PCS Channels
Altera Transceiver PHY IP Core November 2012 Altera Corporation
User Guide
Timing Constraints for Reset Signals when Using Bonded PCS Channels
For designs that use bonded TX PCS channels, the reset signal to all TX PCS channels
within a bonded group must meet a maximum skew tolerance. This skew tolerance is
one-half the TX parallel clock cycle.
You must provide a Synopsys Design Constraint (SDC) for the reset signals to
guarantee that your design meets timing. Example 17–1 shows the general form for
this constraint. If your design includes the Transceiver PHY Reset Controller IP Core
or the embedded reset controller, you can substitute your instance and interface
names for the generic names shown in Example 17–1.
In Example 17–1, you must make the following substitutions:
<IP_INSTANCE_NAME>—substitute the name of your reset controller IP instance
or PHY IP instance
<1/2 coreclk period in ps>—substitute the 1/2 the clock period of your design in
picoseconds
If your design has custom reset logic, replace the
*<IP_INSTANCE_NAME>*tx_digital_reset*r_reset with the source register for the
TX PCS reset signal,
tx_digital_reset
.
Altera believes that most designs will meet this maximum skew requirement without
this constraint; however, it cannot be guaranteed without including this constraint.
f For more information about the
set_max_skew
constraint, refer to the SDC and
TimeQuest API Reference Manual.
Example 17–1. SDC Constraint for TX Digital Reset When Bonded Clocks Are Used
set_max_skew -from *<IP_INSTANCE_NAME>*tx_digitalreset*r_reset -to *pld_pcs_interface*
<1/2 coreclk period in ps>
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