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Remove Initial delay not taken into account in DDRx wizard?

Question asked by pascal_pardo on Feb 11, 2011
Latest reply on Feb 14, 2011 by pascal_pardo

Hi,

 

i've been simulating a DDR3 interface by means of the DDRx wizard. The interface consists out of 1 controller and 4 memory devices. Address/Cmd are connected using flyby topology. In the controller there are 2 clock drivers which are routed in a T-branch.

For the Third and Fourth RAM some hold-time margin errors occur.

 

In the DDR_report_data_violations_xxx.xls the Min Hold Time (column Q) is calculated by subtracting the initial delay from the simulated holdtime.

 

If I remove the initial delays from the IBIS model (by means of the command remove initial delays in the visual Ibis editor) I still see the same figures after simulating.

I've expected my Min Hold Time to be equal to the Hold Time since the initial delay has been removed.

Is this a correct assumption?

Is there a difference between initial delay and initial delay delta (mentioned in column Q) ?

If so, what is the difference and how is the initial delay delta calculated or where is it retrieved from?

 

thanks in advance,

 

Best regards,

 

Pascal

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