stage3 [option ... ]
where option is one or more of the following:mask none
mask auto
mask bbox
mask value
debug
route net
force
step
effort number
The stage3 command performs the third stage routing, in which each net is in turn removed and re-routed. The option "mask" (one optional argument) sets the type of mask to be used to limit the search space of the net. See the "stage2" command reference for a complete list. Normally "mask bbox" is used with stage3 routing, as it ensures that there must be at least one route solution (the existing one).The option "route" (one mandatory argument) will attempt a third stage route of the net named net only.
The option "debug" (no arguments) creates a visual display of the search algorithm in the graphics window. This greatly slows down the routing process; it is intended only for diagnostic use.
The option "force" (no arguments) tells qrouter to force a connection to a terminal node, even if qrouter has evaluated all grid positions for the terminal as blocked by obstructions. This will enable a route solution, but will likely cause a DRC error. In rare cases this may allow routing where the vendor cell uses tighter DRC rules for the standard cell than are specified for the routing.
Option "limit" (one mandatory integer argument) will limit the number of colliding routes that can be ripped up in order to make way for a single route solution. If stage 2 routing is done with a mask other than "none", then many simple route solutions may require large numbers of routes in the way to be removed, causing the list of unrouted nets to remain constant or even increase over time. With the limit set, such routes are abandoned, but allows stage 2 to reduce the number of unrouted nets without resorting to using "mask none". This option is only available in qrouter version 1.3.31 and higher.
The option "effort" (one mandatory integer argument) gives the level of effort to find solutions. See the "stage2" command reference for a complete description of the option. Generally, this is not needed for stage3 because routes are guaranteed. However, if stage3 is run while some routes remain, then it will behave more like a stage2 route, and the level of effort becomes meaningful. Option "step" runs the third stage routing on a single net. It is similar to the option "route net", but routes the net that is at the top of the list, as the full stage3 run would do.
stage3 is implemented as a built-in command in qrouter, only in the Tcl version.
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Last updated: June 14, 2017 at 9:18am