Achronix ACE Version 5.0 Manuel d'utilisateur télécharger pdf (Page 378)

set input transition Chapter 5. Tcl Command Reference

set input delay

set input delay delay port pin list [-clock <arg>] [-combinational]

Specify an input delay constraint or clock

Argument Required/Optional Description

delay Required delay value (Note: this value is currently ignored)

port pin list Required port pin list (one or more ports)

[-clock <arg>] Optional clock name

[-combinational] Optional use combinational domain

Elaboration

This command speciﬁes an input delay constraint or clock using a structure speciﬁed by user directives that

have been applied to the design prior to run prepare.

For example user wants to use an input pin as a combinational pin, which is not registered input; below is

the example how to set the input delay inside the SDC ﬁle:

set_input_delay 0 <port_pin_list> -combinational

If the user design has input pins deﬁned as bus. Then in this case user needs to split the bus into a bit and

use the following constraint inside the SDC ﬁle:

set_input_delay 0 {<port_pin_list[bit_value_of_bus]>} -combinational

or in easier way user can use for loop in SDC ﬁle

for {set i 0} {$i < <bus_width>} {incr i} {

set_input_delay 0 <port_pin_list\[$i\]> -combinational

}

For example in user design an input pins (abus [18:0]) are deﬁned as 19-bit bus. Instead of using 19-line

with bit-split user can use this above sample. Below is the example how to deﬁne 19-bit bus inside the SDC

ﬁle:

for {set i 0} ($i < 19) {incr i} {

set_input_delay 0 abus\[$i\] -combinational

}

User can also set the constraint on the input pin with respect to clock. Below is the example how to do this

in the SDC constraint ﬁle

set_input_delay 0 <port_pin_list> -clock <clock_name>

or [If the input pins are bus]

set_input_delay 0 {<port_pin_list[bit_value_of_bus]>} -clock <clock_name>

But it is recommended for the user to register the input pins with respect to design clock instead of using

the above constraint ﬁle.

set input transition

set input transition slew port pin list

Specify an input slew/transition constraint

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Achronix ACE Version 5.0 Manuel d'utilisateur Page 378