Intel® Quartus® Prime Software
Intel® Quartus® Prime Design Software, Design Entry, Synthesis, Simulation, Verification, Timing Analysis, System Design (Platform Designer, formerly Qsys)
Announcements
Intel Support hours are Monday-Fridays, 8am-5pm PST, except Holidays. Thanks to our community members who provide support during our down time or before we get to your questions. We appreciate you!

Need Forum Guidance? Click here
Search our FPGA Knowledge Articles here.
15558 Discussions

How do we set a "keep" or "preserve" attribute to a wire, from QSF or without modifying the code?

Sajith_K_Intel
Employee
447 Views

How do we set a "keep" or preserve attribute to a wire in my design, from QSF without modifying the code?

 

Quartus 19.4 have PRESERVE_REGISTER setting, but for registers. What I would like to place attribute is on a wire. The wire name is getting changed due to packing/merging to LUTs and other combo nets.

0 Kudos
1 Solution
KhaiChein_Y_Intel
201 Views

Hi,

 

Yes. The attribute preserve is supported through HDL only.

 

Thanks.

Best regards,

KhaiY

View solution in original post

4 Replies
sstrell
Honored Contributor III
201 Views

Unfortunately, I don't think this is possible without using a synthesis attribute in the code. However, have you tried preserving the registers before or after the logic where you're seeing the name changes?

 

And if you don't want the packing and merging you mention to occur at all, look at some of the logic options/assignments that start with "Auto" that might prevent the changes from happening.

 

#iwork4intel

KhaiChein_Y_Intel
201 Views

Hi,

 

May I know if you have any updates?

 

Thanks.

 

 

Sajith_K_Intel
Employee
201 Views

@sstrell​ it did not work as expected. Also since the design is large, there are multiple registers on either side of the node. it is hard to put preserve on those every registers.

I was wondering why Quartus do not support this feature, while they support it through HDL modification.

KhaiChein_Y_Intel
202 Views

Hi,

 

Yes. The attribute preserve is supported through HDL only.

 

Thanks.

Best regards,

KhaiY

Reply