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Chapter 7
Autorouting and Autoplacement
Caution
The Default button sets default values for all tabs in the Routing Options dialog
box.
In general, high rip-up control values increase the persistence and intensity of the
Note
rip-up and routing process. Thus, high values are especially useful for special tasks, such
as achieving 100 percent completion without intermediate router passes.
NI Ultiboard User Manual
4.
Edit one or both of the following fields in the Optimization area:
•
Change Direction Cost Factor—A high direction cost factor
limits the number of trace corners the optimizer creates. A low
factor allows frequent changes in routing direction.
•
Equi-Space Trace Cost Factor—A high value here indicates that
traces will be spread out more during optimization, with a
resultingly higher cost.
5.
If you wish to return the values to the default settings for Ultiboard,
click Default.
Routing Options: Rip-Up Tab
Complete the following steps to set up rip-up parameters:
1.
Select the Rip-Up tab in the Routing Options dialog box.
2.
Edit one or more of the fields in the Rip-up Trees area:
•
Maximum Rip-Up Trees—Sets the maximum number of traces
that can be ripped up during each rip-up cycle.
•
Maximum Rip-Up Depth—Controls the persistence of the
rip-up process. The higher the value you set, the greater the
persistence each rip-up cycle has (that is, the more ways the
placement is analyzed before a final placement is made).
•
Maximum Rip-Up Retries—Sets the maximum number of
rip-up retries for each trace. The higher the number of retries you
set, the greater the rip-up intensity in each trace.
•
Distance-1 (0 or 1 Grid) Cost Factor—Controls the use of
channels left by ripped-up traces in the near distance (0-1 grid
point, trace-to-trace). A high value results in infrequent use of
these channels, forcing relatively more local changes during
rip-up and retry routing. A low factor permits the router to use
these channels freely.
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