create_clock with pre map signals....

Either nobody else has a clue, or this is such a clueless question no one wants to waste their time with it :)

For what it is worth, it does appear the (* keep = 1 *) and /* synthesis keep = 1 */ don't work with vqm files in particular. I guess I'm leaning towards one of two things

1) declaring that this feature only works in source code (modulo restrictions listed on page 9-47 of the user manual) before processed by the gui in particular ??

2) doing timing driven synthesis from the start may allow certain timing requirements to car through mapping to the fit stage... Otherwise, one needs to presume a clock net or device is there and won't be optimized away or else one always does timing interactively, which I have a hard time believing is the case (hmm, that certainly that's what timequest, etc, implies)...

I'll ping support and let y'all know what I find out...

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I've gone through the online training for timing quest, I've read everything I can find in the user manual, and I'm still missing something..

I really want to be able to use create_clock and create_generated_clock on a pre map net name. After mapping, the net names a all changed up (and with fine reason - optimization and all), and SDC files are not read until after mapping and before fitting....

It seems like there must be a way to do this more automatically without mapping first, running the gui, doing a bunch of searching, getting it wrong a bunch of times, retrying etc...

One idea I had was the try to keep the wire around, even though that certainly may be less optiimal with

wire generatedClockA /* synthesis keep = 1 */; // verilog

But this doesn't keep the net around, or at least I can't see that it does (hmm, can I dump out a dump map netlist to verify this or not ? Meaning that if I try to use that net in the create clock command, it doesn't find that net.

I guess the clock divider always sticks around, but it's buried down a few levels of hierarchy, as the report tells me *after* I've run fit...

I'm must be missing something basic here, or are clocks really always a completely interactive setup everytime you change add or delete internal clocks???

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Hi,

normally timing constraints are applied to a design before synthesis and mapping, because the constraint should guide the tool to reach the design requirements.

Why do you want to set the contraints on the pre-mapped netlist ?

Kind regards

GPK