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AR# 60040

PC-CFR v5.0- Update auto generated XDC Constraint file when core target for UltraScale devices.

Description

PC-CFR v5.0 uses an xdc constraint file during the implementation phase to convert all of the BRAMs from READ_FIRST to WRITE_FIRST mode.

This conversion is critical to achieving high F-max for PC-CFR v5.0.

The current .xdc  file that is being generated by Vivado during the IP generation does not do READ_FIRST to WRITE_FIRST conversion for UltraScale devices.

Solution

This is known issue with PC-CFR v5.0 and only arises with UltraScale devices in Vivado 2014.1


The corresponding lines have to be updated in the .xdc file to make it work for UltraScale devices.
 

The below lines can be found in the existing XDC file.
set_property WRITE_MODE_A WRITE_FIRST [get_cells -hierarchical -filter { PRIMITIVE_TYPE =~ BMEM.bram.* } ]
set_property WRITE_MODE_B WRITE_FIRST [get_cells -hierarchical -filter { PRIMITIVE_TYPE =~ BMEM.bram.* } ]

They need to be replaced with the lines below for UltraScale devices.
set_property WRITE_MODE_B WRITE_FIRST [get_cells -hierarchical -filter { PRIMITIVE_TYPE =~ BMEM.bram.* || PRIMITIVE_TYPE =~ BLOCKRAM.BRAM.* } ]

set_property WRITE_MODE_A WRITE_FIRST [get_cells -hierarchical -filter { PRIMITIVE_TYPE =~ BMEM.bram.* || PRIMITIVE_TYPE =~ BLOCKRAM.BRAM.* } ]

A sample XDC file is attached for reference.

Attachments

Associated Attachments

Name File Size File Type
pc_cfr_v5_0.xdc 947 Bytes XDC
AR# 60040
Date Created 04/01/2014
Last Updated 05/06/2014
Status Active
Type General Article
IP
  • Peak Cancellation Crest Factor Reduction (PC-CFR)