Intel® Quartus® Prime Pro Edition User Guide: Scripting

ID 683432
Date 10/04/2021
Public

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Document Table of Contents

3.1.27.27. set_max_delay (::quartus::sdc)

The following table displays information for the set_max_delay Tcl command:

Tcl Package and Version

Belongs to ::quartus::sdc

Syntax set_max_delay [-h | -help] [-long_help] [-fall_from <names> ] [-fall_to <names> ] [-from <names> ] [-rise_from <names> ] [-rise_to <names> ] [-through <names> ] [-to <names> ] <value>
Arguments -h | -help Short help
-long_help Long help with examples and possible return values
-fall_from <names> Valid source clocks (string patterns are matched using Tcl string matching)
-fall_to <names> Valid destination clocks (string patterns are matched using Tcl string matching)
-from <names> Valid sources (string patterns are matched using Tcl string matching)
-rise_from <names> Valid source clocks (string patterns are matched using Tcl string matching)
-rise_to <names> Valid destination clocks (string patterns are matched using Tcl string matching)
-through <names> Valid through nodes (string patterns are matched using Tcl string matching)
-to <names> Valid destinations (string patterns are matched using Tcl string matching)
<value> Time Value
Description

Specifies a maximum delay exception for a given path. The maximum delay is similar to changing the setup relationship (latching clock edge - launching clock edge), except that it can be applied to input or output ports without input or output delays assigned to them. Maximum delays are always relative to any clock network delays (if the source or destination is a register) or any input or output delays (if the source or destination is a port). Therefore, input delays and clock latencies are added to the data arrival times. Clock latencies also added to data required times and output delays are subtracted from data required times. The -from and -to values are collections of clocks, registers, ports, pins, or cells in the design. If the -from or -to values are not specified, the collection is converted automatically into [get_keepers *]. It is worth noting that if the counterpart to the unspecified collection is a clock collection, it is more efficient to explicitly specify this collection as a clock collection but only if the clock collection also generates the desired assignment. Applying exceptions between clocks applies the exception from all register or ports driven by the -from clock to all registers or ports driven by the -to clock. Applying exceptions between a pair of clocks is more efficient than for specific node to node or node to clock paths. If pin names or collections are used, the -from value must be a clock pin and the -to value must be any non-clock input pin