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

[Sajith_K_Intel]

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.

[sstrell]

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]

Hi,

May I know if you have any updates?

Thanks.

[Sajith_K_Intel]

@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 · Accepted solution]

Hi,

Yes. The attribute preserve is supported through HDL only.

Thanks.

Best regards,

KhaiY