Xilinx Constraints Guide

PCF Syntax
item MAXDELAY = maxvalue [PRIORITY integer];
where
• item can be:
– ALLNETS
– NET name
– TIMEGRP name
– ALLPATHS
– PATH name
– path specification
• maxvalue can be a:
– numerical time value with units of micro, ms, ps, or ns
– numerical frequency value with units of GHz, MHz, or KHz
– TSidentifier
Constraints Editor Syntax
Chapter 4: Xilinx Constraints
To open Constraints Editor, select ISE® Design Suite > Processes > User Constraints >
Exceptions > Timing Constraints > Nets.
FPGA Editor Syntax
To set MAXDELAY to all paths or nets, select File > Main Properties > Global Physical
Constraints.
To set MAXDELAY to a selected path or net, with a routed net selected, select Edit >
Properties of Selected Items > Physical Constraints.
Constraints Guide
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