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# -*- tcl -*-

# $Id: cdc_signal_s1.xdc 759 2016-04-09 10:13:57Z mueller $

#

# Copyright 2016- by Walter F.J. Mueller 

# License disclaimer see LICENSE_gpl_v2.txt in $RETROBASE directory

#

# cdc constraints for cdc_signal_s1

#

# Revision History:

# Date         Rev Version  Comment

# 2016-04-08   759   1.0    Initial version

#

set clko [get_clocks -of_objects  [get_cells R_DO_S0_reg]]

set clko_per80 [expr {0.8 * [get_property -min PERIOD $clko]}]

#

# CLKI->CLK0

# ensure timing delay in DI smaller than a receiver clock cycle

#   Note: -datapath_only requires -from to be specified; -from must be a

#         clock (or primary port); a -from clock can't be reliably determined

#         because 'single signal' synchronizer might be driven by logic or

#         even by a constant. So simply use [get_clock], thus all clocks.

set_max_delay \

  -from [get_clocks] \

  -to   [get_cells {R_DO_S0_reg}] \

  -datapath_only  $clko_per80