AR# 16971

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5.2i xilinx2primetime - How can I obtain the global OFFSET constraints to be used in PrimeTime?

Description

Keywords: offset, clock

Urgency: Standard

General Description;
How can I obtain the global OFFSET constraints to be used in PrimeTime?

Solution

Global OFFSET IN and OFFSET OUT for Multi-clock Designs
These global constraints are not translated to bit-blasted SDC constraints. The xilinx2primetime program detects the presence of these constraints in the PCF file for multi-clock designs and informs you of this limitation. The work-around for this problem is to use the trace.tcl script. The trace.tcl script was co-developed with Synopsys to help you create the proper set_input_delay and set_output_delay constraints for the FPGA's inputs and outputs.

Example
set_input_delay 5 -clock "CLK_global" [remove_from_collection [all_inputs] [get_ports {CLK_global}]]
set_output_delay -5 -clock "CLK_global" [all_outputs]
set_input_delay 20 -clock "CLK_local" [remove_from_collection [all_inputs] [get_ports {CLK_local}]]
set_output_delay 5 -clock "CLK_local" [all_outputs]

NOTE: In the 6.1i release of ISE (scheduled for August 2003), this limitation will be fixed and you will no longer need the trace.tcl script.
AR# 16971
Date 03/06/2005
Status Archive
Type General Article
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