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AR# 12747

7.1i XST - Does XST support cross-clock domain analysis?


General Description:

XST does not automatically take inter-clock domains into account during timing optimization. Does XST support cross-clock domain analysis?


Yes. To activate cross-clock domain analysis, you must set a switch in XST. This is only supported in command line mode (it is not supported in ISE). You can set this switch via the following option:

-cross_clock_analysis YES

For example:

run -ifn <INPUT_FILE_NAME>.vhd -ifmt VHDL -p xcv50-bg256-6 -ofmt NGC -ofn xst_demo -cross_clock_analysis YES


"-ifn" is the input file name

"-ifmt" is the input HDL format (Verilog or VHDL)

"-p" is the target part

"-ofmt" is the output format (EDIF or NGC)

"-ofn" is the output file name

This is a GUI option in 10.1 under synthesis properties.
AR# 12747
Date Created 08/29/2007
Last Updated 04/12/2012
Status Archive
Type General Article