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Timing constraint and $recovery system task (Read 4821 times)
Patislas
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Timing constraint and $recovery system task
Apr 01st, 2011, 2:09am
 
Hello,

I'm using verilog models of a dual port ram memory.
When operations are done simultaneously at the same address on the two ports without respecting the Tcc timing constraint a collision occurs, WriteA/ReadB for example. In this case the Read on the port B fails and the output is corrupted (put at X). In order to check the Tcc timing constraint the task $recovery is used:
$recovery(posedge CLKA &&& csba_en,posedge CLKB &&& (flag_collisionB ==1'b1), tcc, warningCCB);
Using this task makes it possible to back annotate the tcc timing constraint (with SDF file) and to check collision violations.

Unfortunately the $recovery task generates an error message in the log when the collision occurs.
I do not want to have these error message, so I was wondering if it is possible to skip this error messages, or to modify this system task in order to delete the error message. Any idea ?
Thank you
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boe
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Re: Timing constraint and $recovery system task
Reply #1 - Apr 1st, 2011, 1:28pm
 
Patislas,

That depends on your simulator - check the manual. Our simulator usually generates warnings, which can be disabled by command line option.

B O E

[Edit:]PS: "Try to ask specific and bounded questions. You are much more likely to get a response." (Forum guidelines)
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Patislas
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Re: Timing constraint and $recovery system task
Reply #2 - Apr 4th, 2011, 2:36am
 
Thank you for your response.
I write the models and It will be used by other persons, so setting the simulator may not be an optimal solution.

Is it possible to get the code of this system task in order to rewrite it ?

My aim is just to be able to back-annotate the tcc timing and check collisions whitout generating error/warning messages
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boe
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Re: Timing constraint and $recovery system task
Reply #3 - Apr 4th, 2011, 4:29am
 
Patislas wrote on Apr 4th, 2011, 2:36am:
Is it possible to get the code of this system task in order to rewrite it ?

My aim is just to be able to back-annotate the tcc timing and check collisions whitout generating error/warning messages
I haven't done this yet, I suppose the PLI (programming language interface) might offer a solution. You can ask your tool vendor for support, they may be able to help.

B O E
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haykp
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Re: Timing constraint and $recovery system task
Reply #4 - Apr 5th, 2011, 3:59am
 
I certainly remember that for ncverilog and vcs simulators there was some input option which suppress he messages. Unfortunately don't remember the name.

Regarding to PLI,not sure that you will fins a solution because displaying warnings is simulator option.
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boe
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Re: Timing constraint and $recovery system task
Reply #5 - Apr 5th, 2011, 11:25am
 
haykp,

I assumed that Patislas does not want to globally turn off all the timing error messages.

B O E
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