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Constraint set up for delta and tolerance

jemarods

Hi all,

 What is the difference of setting up a delta of 0 , tolerance of 50.... (so 0:50)

with

no delta, tolerance of 100...... (so :100)

since in my case, a target appears if a delta is used.

follow up question:, how does constraint manager identifies a target net....?

Thanks in advance!!

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  • OK, let's say you have a 16-bit bus, a tolerance means that the length, in this case, of all 16 must be within the specified tolerance +/- 100 (:100) with no particular preference to any of the nets, called a "matched delay". As you found, a delta means that ONE of the nets is picked as a target, typically the longest unrouted but PCB Editor takes a "guess" at this and you can use right-click>Set as Target in CM if you want another target, you then get the delta and tolerance, delta could be 0, applied to the other 15 nets, with respect to the target, called a "relative delay". (See cmug.pdf, doc\cmug in the installation, page 56 for 16.6 for the description)
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  • OK, let's say you have a 16-bit bus, a tolerance means that the length, in this case, of all 16 must be within the specified tolerance +/- 100 (:100) with no particular preference to any of the nets, called a "matched delay". As you found, a delta means that ONE of the nets is picked as a target, typically the longest unrouted but PCB Editor takes a "guess" at this and you can use right-click>Set as Target in CM if you want another target, you then get the delta and tolerance, delta could be 0, applied to the other 15 nets, with respect to the target, called a "relative delay". (See cmug.pdf, doc\cmug in the installation, page 56 for 16.6 for the description)
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