cancel
Showing results for 
Show  only  | Search instead for 
Did you mean: 
demetrio
Visitor
Visitor
5,436 Views
Registered: ‎10-26-2009

How can I preserver a module which has no output signals in XST

I know it can add syn_pronune attribute in Synplify tools, but what can I do in XST

 

 

0 Kudos
5 Replies
htsvn
Xilinx Employee
Xilinx Employee
5,429 Views
Registered: ‎08-02-2007

Hi,

 

Use a KEEP constraint.

 

This information is available in cgd.pdf that is available in the location ISE_Install\doc\usenglish\books\docs\cgd

 

This is under Xilinx Constraints Unit of cgd.

 

Thanks.

----------------------------------------------------------------------------------------------
Kindly note- Please mark the Answer as "Accept as solution" if information provided is helpful.

Give Kudos to a post which you think is helpful and reply oriented.
----------------------------------------------------------------------------------------------
0 Kudos
demetrio
Visitor
Visitor
5,405 Views
Registered: ‎10-26-2009

Thank you for your advice

 

But my question is about when I want to keep a module not only one signal

 

The artical show me that the KEEP attribute is only applied on signal? How do you define a signal, a wire or a reg definition?

0 Kudos
htsvn
Xilinx Employee
Xilinx Employee
5,395 Views
Registered: ‎08-02-2007

Hi,

 

Check the snapshot below to show how to keep a signal from being removed. As we see that the signals do exist in the netlist.

 

Use this as a part of your code.

 

attribute keep : string;attribute keep of sig_or2_2_z : signal is "TRUE";

attribute keep of sig_or2_1_z : signal is "TRUE";

 

Thanks   

 

 

----------------------------------------------------------------------------------------------
Kindly note- Please mark the Answer as "Accept as solution" if information provided is helpful.

Give Kudos to a post which you think is helpful and reply oriented.
----------------------------------------------------------------------------------------------
Keep_Constraint.JPG
0 Kudos
demetrio
Visitor
Visitor
5,355 Views
Registered: ‎10-26-2009

Sorry, you just misunderstand my question is how to preserver a module as its has no output for example

 

This module is almost not finished but need to evaluate its performance and area

 

Thank you again.

0 Kudos
ywu
Xilinx Employee
Xilinx Employee
5,299 Views
Registered: ‎11-28-2007

According to XST UG, syn_noprune attribute is automatically recognized by xst (see the attached snapshot). Does it not work for you?

 

Cheers,

Jim


demetrio wrote:

I know it can add syn_pronune attribute in Synplify tools, but what can I do in XST

 

 


 

 

Cheers,
Jim
ScreenHunter_05 Nov. 13 00.40.gif
0 Kudos